JANUARY 27, 1977

THE

NAUTILUS

Vol. 91

No. 1

A quarterly

devoted to

malacology and

the interests of

conchologists

Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker.

Editor-in-Chief: R. Tucker Abbott

EDITORIAL COMMITTEE

CONSULTING EDITORS

Dr. Arthur H. Clarke, Jr.

Department of Mollusks

National Museum of Canada

Ottawa, Ontario, Canada K1A-0M8

Dr. William J. Clench

Curator Emeritus

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. William K. Emerson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 10024

Mr. Morris K. Jacobson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 10024

Dr. Aurele La Rocque

Department of Geology

The Ohio State University

Columbus, Ohio 43210

Dr. James H. McLean

Los Angeles County Museum of Natural History

900 Exposition Boulevard

Los Angeles, California 90007

Dr. Arthur S. Merrill

Biological Laboratory

National Marine Fisheries Service

Oxford, Maryland 21654

Dr. Donald R. Moore

Division of Marine Geology

School of Marine and Atmospheric Science

10 Rickenbacker Causeway

Miami, Florida 33149

Dr. Joseph Rosewater

Division of MoUusks

U. S. National Museum

Washington, D.C. 20560

Dr. G. Alan Solem

Department of Invertebrates

Field Museum of Natural History

Chicago, Illinois 60605

Dr. David H. Stansbery

duseum of Zoology

/he Ohio State University

Columbus, Ohio 43210

Dr. Ruth D. Turner

Department of Mollusks

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. Gilbert L. Voss

Division of Biology

School of Marine and Atmospheric Science

1 0 Rickenbacker Causeway

Miami, Florida 33149

Dr. Charles B. Wurtz

3220 Penn Street

Philadelphia, Pennsylvania 19129

KDITOR-IN-CHIEF

Dr. R. Tucker Abbott

Delaware Museum of Natural History

Box 3937, GreenvUle, Delaware 19807

Mrs. Horace B. Baker

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Havertown, Pennsylvania 1 9083

OFFICE OF PUBLICATION

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Sut)scrlptlon Price: $7.00 (see inside back cover)

THE

NAUTILUS

Volume 91, Number 1— January 27, 1977

CONTENTS

Raymond W. Neck

Geographical Range of Praticolla griseola (Polygyridae, Correction and Analysis 1

David Nicol

Geographic Relationship of Benthic Marine Molluscs of Florida 4

William F. Gale

Growth of the Fingernail Clam, Sphaerium transversum (Say) in the Field

and Laboratory Experiments 8

Eileen H. Jokinen

The Formation and Structure of the Shell Varix in Stagnicola elodes (Say)

(Gastropoda: Lymnaeidae) 13

WiUiam H. Gilbert and Ellen F. Suchow

Predation by Winter Flounder (Psevdopleuronectes amerkanus) on the

Siphons of the Clam, Tellina agilis 16

Dee S. Dundee and Anna Paine

Ecology of the Snail, Melanoides tuberculata (Miiller), Intermediate Host of the

Human Liver Fluke (Opisthorrhiii sinerms) in New Orleans, Louisiana 17

Joseph C. Britton and Clifford E. Murphy

New Records and Ex;ological Notes for Corincvla manilensis in Texas 20

Elizabeth V. Gardo

Opisthobranchs Found Off Little Egg Inlet, New Jersey, with Notes on Three

Species New to the State 23

William G. Lyons

Notes on Occurence of Eupleura sulcidentata Dall (Gastropoda: Muricidae) 28

Henk K. Mienis

North American Land Snails in Israel 30

S. K. Raut and K. C. Ghose

Effect of Upwardly-directed Shell Aperture on the Aestivating Land Snail, Achatina fuiica 31

Ralph W. Taylor and Clement L. Counts, III

The Asiatic Clam, Corbicula manilensis, as a Food of the Northern Racoon, Procyon lotor 34

Obituary of Allyn Goodwin Smith (1893-1976) 37

Publications received 7

Book review: (of) S. van der Spoel 36

STATEMENT OF OWNERSHIP, MANAGEMENT AND CIR-

CULATION (Required by) Act of October 23, 1962: Section

4396 Title 39. United States Code, and postal regulation

132-622.

1.

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a

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Titleof publication: THE NAUTILUS

Date of filing, September 25, 1976.

Frequency of Issue: Quarterly (4 per year).

Location of known office of publication: Delaware

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Greenville, De. 19807.

Location of the Headquarters of General Business

Offices of the Publishers: Delaware Museum of

Natural History, Kennett Pike, Box 3937, Greenville,

De 19807.

Names and addresses of publisher, editor, and

managing editor: Publisher, Mrs. Horace Burrington

Baker, 11 Chelten Rd., Havertown, Pa. 19083. Editor,

R. Tucker Abbott, Delaware Museum of Natural

History, Box 3937, Greenville, De. 19807. Managing

editor, none.

Owner: Mrs. Horace Burrington Baker, 11 Chelten

Rd., Havertown, Pa. 19803.

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LIVING MARINE

MOLLUSCS

C. M. Yonge and T. E. Thompson

BEHAVIOUR

Two distinguished British marine biologists have combined their knowledge and talents to

produce a compact, well-rounded account of the largest marine group of animals.

"The first modem book on the biology of marine moUusks

that is of textbook quality, yet so beautifully written

and illustrated that the legions of amateur conchologists

will readily absorb its wealth of information"—/?. Tucker

Abbott, Ph.D.

Send check or money order to:

American Mulacologistx, Puhl.

P.O. Box 4208

Greenville, De. 19807 U.S.A.

Available March 1977

Clothbound, 288 pp., 162 text figures, 16 plates with 18 glorious color photographs of living

marine molluscs. Only $13.9.5.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 1

GEOGRAPHICAL RANGE OF PRATICOLELLA GRISEOLA (POLYGYRIDAE)

CORRECTION AND ANALYSIS

Raymond W. Neck

Texas Parks & Wildlife Department

John H. Reagan Office Bldg.

Austin, Texas 78701

ABSTRACT

The geographical range of Praticolella griseola (Pfeiffer) in Texas and Mexico is

discussed; erroneous but published collecting sites are discussed. The climatic

causes of the discontinuity of geographic range of the species are discussed.

Three species of Praticolella von Martens

(Polygyridae) occur in Texas: pachyloma (Menke),

berlandieriana (Moricand) and griseola (Pfeiffer).

Early records placed griseola over much of

southern and central Texas; these records were

later corrected only to be subsequently

republished. In light of the reoccurrence of

this misinformation, all literature records are

reconsidered and the geographical range of

griseola is re-evaluated. Mexican and Central

American records of this species are also discussed.

Confusion of the range of griseola is no doubt

due to a lack of definite phenotypic breaking

points between griseola and berlandieriana even

though the classic types are quite different. Some

workers have felt that these two species definite-

ly blend together (von Martens 1892; Singley

1893) while others such as Pilsbry (1940:695) felt

that there were "no common links" between

them. Genitalia of berlandieriana and griseola

are similar but distinguishable (Webb 1967). A

definitive solution to the taxonomic problem wall

be difficult to obtain and may be impossible due

to contemporary habitat destruction. Adding to

the complexity is the possibility of hybridization

involving all three species in southern Texas

(Hubricht 1961; in Cheatum and Fullington 1971).

The first published records of P. griseola that I

have found are those of Binney (1885:394) for

Calhoun (at Indianola) and Bosque Counties.

Townsend (1897) reported it on the "lower Rio

Grande." Pilsbry (1940:690-692) completely dis-

counted the Bosque County record and doubted

the Indianola record. P. griseola is native in

neither county. Pilsbry gave the range of griseola

as "environs of Brownsville" which is in Cameron

County.

In the first synthesis of Texas molluscan

records, J. A. Singley (1893) reported griseola

from the following counties: Caldwell, Cameron,

Duval, Gillespie, Goliad, Gonzales, Kendall,

Milam (from Askew); Lampasas (from Mrs.

Sinks); Williamson (from Walker); Bexar, Comal,

Hays, Travis (Strecker's personal records).

In the next compilation of Texas snail records,

J. K. Strecker (1935) reported specimens in his

collection from Cameron and Hidalgo Counties.

He stated that "all other counties Singley men-

tions for P. griseola are no doubt based on P.

berlandienana" except Duval County. No reason

was given for acceptance of the Duval County

record.

The latest compilation of Texas polygyrid snail

records (Cheatum & Fullington 1971) re-publishes

the suspect records of Singley with no mention of

the intervening correction by Strecker. No men-

tion is made, however, of the records of Binney.

Significantly, all post-Singley records listed by

Cheatum and Fullington come from Cameron and

Hidalgo Counties in south Texas along the Rio

Grande River.

Thus, we are left with positive records for only

two counties for griseola in Texas. Personal col-

lecting in most of the central Texas counties has

revealed no populations of griseola. I have per-

sonal records from Brownsville (southern

Cameron County) and Laguna Atascosa Wildlife

Refuge (northeastern Cameron County). Webb

2 THE NAUTILUS

January 27, 1977

Vol. HI (1)

(1967) worked with griseola collected at Harl-

ingen (central Cameron County) by J. Campbell.

Such a restricted Texas range for land snails is

not unique, as Euglandina texasiana (Pfeiffer)

and Thiisdiinphiira plaginpt i)cha (Shuttlewnrth)

exhibit similar distributions. These snails in

Texas are restricted to soils of the modem delta

of the Rio Grande River which includes southern

and eastern Hidalgo County, all of Cameron

County and most of Willacy County. Shells of

griseola have not yet been repwrted from Willacy

County although the Laguna Atascosa locality is

no more than thirteen kilometers from the

Cameron-Willacy county line. Shells collected by

Ideker in Willacy County in 1974 included no

definite griseola shells although some berlan-

dieriana shells from this area may indicate in-

trogression with griseola. Populations of gyiseola

are to be expected in southern Willacy County.

The south Texas populations of g-riseola are

isolated from Mexican populations (except for

those in the southern Rio Grande delta) which oc-

cur no further north than the Tampico area at the

border between Vera Cruz and Tamaulipas. Other

populations occur at scattered localities in north-

ern Yucatan, Guatemala and Nicaragua (Rehder

1966).

Other populations have resulted from introduc-

tions. McLellan (19.50) reported griseola (could it

have been berlandieriana?) to be abundant in his

yard and adjacent lots in Bellaire, Harris County,

Texas. Other adventive populations include Cuba

(probably from Vera Cruz) and Key West,

possibly from Cuba (Pilsbry 1940:642).

The disjunction of populations of griseola is

similar to the dry lowland tropical Gulf Arc

distribution as exhibited by several species of

reptiles and amphibians (Martin 1958:92-94).

Herptile migration between these areas may have

occurred via a dry corridor through presently wet

tropical woodland areas at some time in the

Pleistocene. The occurrence of the Texas popula-

tions of griseola indicates a northward extension

of its normal range. At some time in the recent

past grifiPola apparently existed over large areas

of coastal Central America, Mexico and (at least

southern) Texas.

Environmental change may have resulted in

widespread extinction of griseola, with survival

occurring only in a few scattered refugia. The

restriction of griseola in Texas to the relatively

mesic deltaic soils of the Rio Grande River in-

dicates that increased aridity was the en-

vironmental factor involved. The area between

the Rio Grande delta and the Panuco River

floodplain (Tampico area) contains only one

significant drainage system. The floodplain of the

Rio Soto La Marina in Tamaulipas should be ex-

amined for populations of griseola. Although the

entire area is arid, these rivers provide suitable

moisture as a result of periodic flooding. The

decline of griseola may have been accompanied

by an expansion of berlandieriana, as the latter

species occurs (possibly sparingly) in the area

between the Rio Grande River and Rio Soto La

Marina (Rehder 1966). A similar range disjunc-

tion in northeastern Mexico is exhibited by the

Texas pocket gopher (Selander et al. 1962).

The second break is apparently not due to

aridity. On the contrary, the break below Vera

Cruz may result from excess moisture in the

humid forest of the Campeche Lowlands. This

area exhibits higher temperature, rainfall and

humidity levels than either bordering area which

contains griseola (Vivo E. 1964), Competition

from tropical snail species specifically adapted to

warm, moist habitats may exclude griseola.

Much additional field work on geographic and

habitat distribution of griseola is needed before a

definitive answer to the reasons for range

fragmentation and existence of particular refugia.

It is difficult at best to correlate the distributions

of organisms with compilations of environmental

data from the literature. The refugia of griseola

apparently represent areas of varied vegetation,

geological and climatic regimes (Leopold 1950;

Wagner 1964; West 1964; Vivo E. 1964). Alter-

nate wet-dry cycles could be important because

Webb (1967) indicated such conditions were

necessary for the culture of both griseola and

berlandieriana.

Fragmentation of the species range of griseola

would be favorable for genetic differentiation be-

tween refugia. This has, apparently, occurred as

Rehder (1966) reported "P. griseola consists of a

number of more or less well-characterized races"

which he based on shell characters.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 3

One additional factor may be involved in the

spotty distribution of griseola. A number of

workers have suggested that griseola is not native

to Yucatan and Guatemala (Bequaert & Clench

1936; Harry 1950). All Guatemalan material (see

Goodrich & van der Schalie 1957) was probably

collected within a 20 km radius of each other ac-

cording to Harry (1950); furthermore all Yucatan

material collected by Harry (1950) definitely was

from such a small area. These two centers of

distribution are about 500 km apart. In these

areas griseola is found exclusively in sites with

orchards, railroad embankments, urban areas and

savannahs managed for cattle grazing (see Be-

quaert & Clench 1933; Goodrich & van der

Schalie 1937). Basch (1959) did not find griseola

in Tikal National Park, Guatemala. Other

workers failed to find griseola when collecting in

various parts of Guatemala and the Yucatan

(Hinkley 1920: Pilsbry 1891; van der Schalie 1940).

Stating that griseola is a species of open, rather

than forested areas, Branson & McCoy (1963) felt

that "man may augment the distribution of this

form by his clearing activities, rather than ac-

tually transporting it to new localities."

Time and source of these putative introduc-

tions into these southern areas are unknown. The

existence of noticeable phenotypic types or

"races" in the various areas of occurrence in-

dicates the possibility of early introduction

(pre-Conquest). Mayan and pre-Mayan set-

tlements have existed in this area for centuries.

Introduction of a limited stock (founder effect)

and/or natural selection for individuals better

adapted to local conditions would result in such

genetic differentiation. The most likely source

would be the Tampico-Vera Cruz populations,

simply because of its close proximity. Branson &

McCoy (1965) reported that specimens from

Campeche were intermediate between Yucatan

and Guatemalan material but closer to the

Guatemalan specimens.

The possibility of these populations being in-

troduced to southern Texas is a strong possibility.

Although almost all areas of the southern tip of

Texas have been cleared or overgrazed at some

time in the past century, griseola does not appear

to be particularly associated with human impact

areas. One would not expect a snail from tropical

Mexico to flourish in natural habitats of sub-

tropical Texas. Frosts occur in most years and

hard freezes are not unkown. Additionally, long

periods of dryness accompanied by high temper-

atures are common in this area. A number of

foreign snails have become established in this

area (Neck, R. W. 1976). These snails, however, are

generally restricted to human -associated sites.

LITERATURE CITED

Basch. P. F. 19.59. Land molluscs of the Tikal National Park.

Guatemala. Mas. Zoot. Univ. Mich. Occ. Pap. 612: 1.5 pp.

Bequaert, J. C. and W. J. Clench. 19,33. The non-marine

mollusks of Yucatan. Carnegie Inst. Wash. Pub.

431:525-545.

Bequaert, J. C. and W. J. Clench. 1936. A second contribution

to the moUuscan fauna of Yucatan. Carnegie Inst. Wash.

Pub. 457:61-75.

Binney, W. G. 1885. A manual of American land snails. Bidl.

U.S.N.M.2S:52Spp.

Branson. B. A. and C. J. McCoy. 1963. Gastropoda of the 1961

University of Colorado Museum expedition in Mexico. The

NautUus'76:Wl-im.

Branson, B. A. and C. J. McCoy. 1965. Gastropoda of the 1962

University of Colorado Museum expedition in Mexico. Univ.

Colo. Stud. Ser. Biol. 13:16 pp.

Cheatum, E. P. and R. W. Fullington. 1971. The Recent and

Pleistocene members of the gastropod family Polygyridae in

Texas. Bull. Dallas Mus. Nat. Hist. 1(1):74 pp.

Goodrich, C. and H. van der Schalie. 1937. Mollusca of Peten

and North Alta Vera Paz, Guatemala. Univ. Mich. Mus.

Zool. Misc. Pubt. 34:.50 pp.

Harry. H. W. 1950. Studies on the nonmarine mollusca of

Yucatan. Mus. Zool. Univ. Mich. Occ. Pap. 524:34 pp.

Hinkley. A. A. 1920. Guatemala mollusca. The Nautilus

34:.37-.55.

Hubricht, L. 1961. Eight new species of land snails from the

southern United States. The Nautilus 75:26-32. 60-63.

Leopold. A. S. 1950. Vegetation zones of Mexico. Ecology

32:.507-518.

von Martens, E. 1892. Land and fresh-water molluscs.

Bioldgia Centrali-Americana. 708 pp.

Martin. P. S. 1958. A biogeography of reptiles and amphibians

in the Gomez Farias region, Tamaulipas, Mexico. Mus. Zool.

Utiiv. Mich. Misc. Pub. 101:102 pp.

McClellan. J. H. 1950. Texas snails. The Nautilus 64:41.

Neck, R. W. 1976. Adventive land snails in the Brownsville.

Texas aLTea.Southwestem Nai uralist 21: 133-135.

Pilsbry, H. A. 1891. Land and fresh-water mollusks collected

in Yucatan and Mexico. Pr(x. Adad. Nat. Sci. Phil, for

1891:310-334.

Pilsbry, H. A. 1940. Land mollusca of North America (north

of Mexico). Monoy. Acad. Nat. Sci. Phil. (3): vol. 1, pt. 2.

4 THE NAUTILUS

January 27, 1977

Vol. 91(1)

Rehder, H. A. 1966. TTie non-marine molluscs of Quintana

Roo, Mexico, with the description of a new species of

IMfmaeus (Pu!monata:Buiimulidae). /Vw. BioL Soc. Wash.

79:27.3-296.

van der Schalie. H. 1940. Notes on mollusca from Alta Vera

Paz, Guatemala. Mxis. Zool. Univ. Mich. Orr. Pap. 413:11 pp.

Selander. R. K.. R. F. .Johnston, B. .J. Wilks and G. G. Raun.

1962. Vertebrates from the barrier islands of Tamaulipas.

Mexico. Univ. Kan. Pub. Mus. Nat. Huit. 12:309-.34.5.

Singley, J. A. 189.3. A preliminar>' list of the land.

fresh-water, and marine mollusca of Texas. Fourth Annual

Rep. Geol. Survey Tex. (1892), Contri. Nat. Hist. Tex. Part

1:299-34.3.

Strecker, .J. K. .Jr. 193.5. Land and fresh-water snails of Texas.

Trans. Tex. Acad. Sci. 17:4-44.

Townsend, C. H. T. 1897. On the biogeography of Mexico and

the southwestern United States. II. Thins. Tex. Acad. Sd.

2(1): 33-86.

Vivo E., J. A. 1964. Weather and climate of Mexico and Cen-

tral .America. In Natural environment and early cultures

(R. C. West. ed.). Handbook of Middle American Indians

1:187-21.5.

Wagner, P. L. 1964. Natural vegetation of Middle America. In

Natural environment and early cultures (R. C. West, ed.).

Handbook of Middle American htdians 1:216-264.

Webb, G. R. 1967. Erotology of three species of Pratieolella,

and ofPolygifra pustula. The Nautilus 80:133-140; 81:11-18.

West. R. C. 196^1. Surface configuration and asscx-iated

geology of Middle America. In Natural environment and

early cultures (R. C. West, ed.). Handbook <f Middle

America Indians 1:43-83.

GEOGRAPHIC RELATIONSHIP OF

BENTHIC MARINE MOLLUSCS OF FLORIDA

David Nicol

Box 14376, University Station,

Gainesville, Florida 32604

ABSTRACT

The geographic distributions of 1,137 species of benthic marine molluscs of

Florida were analyzed. The number of Floridian endemics i'; 110, and those species

not ranging north of Cape Hatteras is 159. The number of boreal or arctic species

that range southward to Florida is only ki. Some species have migrated easticard

to Florida along the Gulf Coast, and these number 158. The majority of Florida's

benthic molluscs appear to have originated in the Caribbean region, and these

species number 779 or 68.i percent of all the species analyzed.

The gastropods have a higher percentage of species endemic to Florida (12. 7 per

cent) as compared to only 3.6 per cent of all the species of pelecypods. and the

pelecypods aymmonly have a higher percentage of geographically wide-ranging

species than the gastropods.

Florida probably has the most diverse marine

shallow-water molluscan fauna in the con-

tinental United States. Because of this, it has

long been a favorite site for shell collectors, and

the molluscs have been thoroughly described by

malacologists. Certainly one of the reasons for

the richness of this molluscan fauna is the fact

that Florida is surrounded by warm shallow

water, and the Florida Keys are less than two

degrees north of the Trupic of Cancer. The

powerful Florida Current sweeps between Cuba

and the Florida Keys and can easily carry

planktonic larvae of Caribbean species north-

ward from Florida to Cape Hatteras, North

Carolina.

In order to show the close relation.ship of the

Caribbean and Floridian molluscan faunas, the

geographic distributions given in two molluscan

faunal monographs were analyzed: Abbott's

American .'<eashplls (second edition, 1974) and

Warmke and Abbott's Caribbean .^eashrlls

(1961). Only the distributions of the benthic

gastropods (mainly prosobranchs), the

pelecypods, the scaphopods, and the

Vol. 91(1)

January 27, 1977

THE NAUTILUS 5

polyplacophorans were studied. Species living at

depths of 200 metere or more were largely

eliminated because they commonly were known

from only one or two dredging stations. The

sample of molluscs analyzed included 750

species of gastropods, 335 species of pelecypods,

30 species of scaphopods, and 22 species of

polyplacophorans. The total number of species

analyzed was 1,137.

The derivation of Florida's benthic marine

molluscan species can be summarized by

grouping them into four categories of

distribution: (1) species probably originating in

Florida and Floridian endemics; (2) species ex-

panding their range southward to Florida along

the Atlantic Coast or those mainly of boreal or

arctic origin; (3) species expanding their range

eastward in the Gulf of Mexico to Florida; (4)

species expanding their range northward to

Florida from the Caribbean region. These are

the categories shown in Table 1.

TABLE 1. Derivation of the benthic molluscs of Florida.

Region

N'l I'J. species Pi'r cent

The number of endemic species, those con-

fined to Florida, is 110. This comprises a sur-

prising 9.7 per cent of all of the molluscs whose

distributions were studied. Besides the species

that are Floridian endemics, there are a few

that are limited to the region extending from

Florida to Cape Hatteras. Most of these

probably originated in Florida and have ex-

panded their range northward. The number of

species that have this limited geographic

distribution is 49, or only 4.3 per cent of all of

the molluscan species studied. K one combines

the number of Floridian endemic species with

those that have a limited range from Florida to

no farther north than Cape Hatteras, the per-

centage of the total fauna in these two classes

is 14 per cent.

The number of boreal or arctic species that

also live in Florida, commonly in moderately

deep water, is only 42, or 3.7 per cent of the

total benthic fauna. Most of these species range

as far north as New England and eastern

Canada and some even have a circum-boreal

and arctic distribution. Some of these boreal

and arctic species that reach Florida are

Solemya velum Say, Nitcula proxima Say,

Niwulana acuta (Conrad), Limopsis cristata Jef-

freys, Limnpsis minuta Philippi, Argopecten

uradians (Lamarck), Limatula subauriculata

(Montagu), Astarie crenata subequilatera Sower-

by, Tlujasira tiisimiata Orbigny, Hiatella arctica

(Linne), Calliostoma bairdii Verrill and Smith,

Crepidula fomicata (Linne), Urosalpinx cinerea

(Say), Anachis lafresnayi (Fischer and Bernardi),

and Ilyanassa obsoleta (Say).

Some of Florida's molluscs are probably im-

migrants from the Gulf Coast that migrated

eastward into Floridian waters. The number of

these species is 158 or 13.9 per cent of the total

fauna analyzed.

The majority of the molluscs of Florida ap-

pear to have had a Caribbean or West Indian

origin. These species number 779 or 68.4 per

cent of all of the species studied. Many of these

species range as far north as Cape Hatteras,

but some are found only in the Florida Keys.

Some of these Caribbean species range as far

north as Cape Canaveral on the east coast of

Florida, and a few live as far north on the

west coast of Florida as Tampa Bay. The mol-

luscan fauna of Florida has been enriched by

many tropical genera from the West Indies

such as: Astraea, Nenta (four species each),

Strombus (five of six species), Triiia (seven

species), Cypraea (five species). Cassis (three

species), Cymatium (eleven species), Tonna (two

species). Bursa (six species), Mitrv, (five species).

Area (two species), Barbatia (four species),

Isognomon (three species), Pinctada (one

species), Spondylus (two species), Lima (three

species), Chama (six species), Pseudochama (one

of two species), and Asaphis (one species). There

are a few notable exceptions to the rule that

6 THE NAUTILUS

January 27. 1977

Vol. 91 (1)

m(jst genera and species originated in the West

Indian area. One of these is the genus Busycon.

with five species living in Florida, and none

found in the Caribbean region proper. Other e.x-

ceptions are Dinocardium robu.'itum (Lightfoot)

and Scaphella junonia (Lamarck).

Waller (1973. p. 32) states that the West In-

dian character of the moUuscan fauna of Ber-

muda has long been known. Many species of

molluscs of Caribbean origin are found in

Florida and also Bermuda. It appears that

almost all of the non-endemic molluscan species

of Bermuda were derived from the Caribbean

region. The distribution maps presented by

Warmke and Abbott (1961) are most helpful in

obtaining some idea of the distribution of the

molluscs of Florida. These distribution maps

clearly show that many of the benthic marine

molluscan species came to Florida from the

Caribbean region. For the Florida Keys and

much of peninsular Florida, more than two

thirds of the molluscan species came from the

Caribbean area.

'Riere are some striking differences in

geographic distribution when one compares the

ranges of the gastropods, pelecypods.

scaphopods, and polyplacophorans with one

another. There are at least two main factors

that influence the differences among these four

classes of molluscs. One is the type of sub-

strate; whether the bottom consists of soft

sediments, which is ideal for burrowing or in-

faunal animals, or whether the substrate is

rockj', which is ideal for epifaunal animals. The

other factor is the mode of reproduction. Are

eggs and sperm simply released into the water

and the eggs fertilized and followed by a long

free-swimming larval stage as. for example, most

pelecypods? Or is fertilization commonly internal

and with a short free-swimming larval stage or

none at all as, for example, in many gastropods?

The comparison of the scaphopod and

polyplacophoran distributions is an example of

TABLE 2. Species endemic to FJimda

Cla^.t Size of sample No. of species Percent

Gastropoda

Peleo'poda

Scaphopcxia

Polyplacophora

750

335

30

22

95 12.7

12 ae

1 3.3

2 9.1

two groups that occupy different types of sub-

strates. The fX)lyplacophorans are found on a

rock or hard shelly substrates or are epifaunal,

whereas the scaphopods live partially buried in

soft sediments, or are basically infaunal. In

Table 4 one sees that five, or 16.7 per cent, of

all scaphopod species appear to have migrated

eastward into Florida along the Gulf Coast, but

none of the polyplacophoran species has this

distribution. Perhaps the lack of a rocky

shoreline along much of the Gulf Coast has

prevented species of polyplacophorans from

moving eastward into Florida. As shown in

Table 3. only one scaphopod species and no

polyplacophorans appear to have a boreal or arctic

origin. Table 2 shows that Floridian endemics are

higher among the polyplacophorans. (two species

or 9.1 per cent as compared to the scaphopods with

one species or 3.3 per cent of thier total species.

This higher rate of endemism among the

polyplacophorans may be caused by the lack of

a rocky shoreline in areas adjacent to Florida.

The polyplacophorans have a higher percentage

of species originating in Caribbean waters as

compared to the scaphopods as shown in Table

5. However, these differences between the

scaphopod and polyplacophoran distributions in

the latter three instances may not be

significant because of the small sample sizes in

these two classes of molluscs.

TABLE 3. Species migrating southivard along the

Atlantic Coast to Florida.

Ga^ Size of sample No. of species Per cent

TABLE 4. Species migrating ecustwat-d along the

Gulf of Mexico to Floiida.

Owi-s

Size of sample Xo. of species Percent

(lastropoda

Pelerypoda

Scaphopcxia

Polyplacophora

TTie pelecypods have a higher percentage of

infaunal species and also a higher percentage of

species that have a free-swimming larval stage

VoJ. 91 (1)

January 27, 1977

THE NAUTILUS 7

TABLE 5. Species migrating northtmrdfrnm the

Caribbean region to Florida.

(IfLss Size o/Saviple No. of species Percent

than the benthic gastropods. The latter factor

is probably the main one as to why the

gastropods have a much higher percentage than

the pelecypods (12.7 per cent as compared to 3.6

per cent) of endemic species. This marked dif-

ference in endemic species is seen in Table 2.

However, some of the apparent greater amount

of endemism among the gastropods may be

because there are many smaller-sized species of

gastropods than pelecypods and because of this,

their geographic distributions are less com-

pletely known. Some of the gastropod species

that Abbott (1974) states are endemic to

Florida are species of small size, 10.0 mm or

less. This does not explain all of the difference

in amount of endemism between the gastropods

and the pelecypods, and it is generally true that

the pelecypods in the Floridian fauna have a

higher percentage of wide-ranging species than

the gastropods. This comparison between the geo-

graphic distributions of benthic pelecypods and

gastropods should be made in other regions to see

if it holds true everywhere because of its

significance to biostratigraphy.

The type of substrate is probably the main

factor that causes pelecypods to have 17.3 per

cent of their species migrating eastward along

the Gulf Coast into Florida as compared to

only 12.7 per cent of all of the species of

gastropods. This difference is seen in Table 4.

As seen in Table 3, the pelecypods also have a

higher percentage of species of boreal or arctic

origin, 6.3 as compared to 2.7 per cent among

all gastropod species. The fact that a higher

percentage of the pelecypods are infaunal as

compared to the gastropods is probably the

main factor because as Thorson (19-57) has faint-

ed out, the diversity of infaunal sf)ecies in-

creases little from the polar regions to the

tropics, but the diversity of the epifaunal

species increases greatly from the polar regions

to the tropics. The percentage of pelecypod

species and gastropod species migrating from

the Caribbean region to Florida is nearly iden-

tical. This is shown in Table 5.

LITERATURE CITED

Abbott, R. T. 1974. American seashells. 2nd. ed., Van Nos-

trand Reinhold Co., New York, 663 p.

Thorson. G. 1957. Bottom communities (sublittoral or shallow

shelf), in Treatise on marine ecology and paleoecology. 1

Ecology, Geol. Soc. Am. Mem. 67, p. 461-.534.

Waller, T. R. 1973. The habits and habitats of some Ber-

mudian marine mollusks. The Nautilus 87(3): 31-52.

Warmke, G. L., and R. T. Abbott. 1%1. Caribbean seashells.

Livingston Publishing G)., Narberth, Penn., 346 p. (Dover

Paperback. 1975).

PUBLICATIONS RECEIVED

Tebble, Norman. 1976. British Bivalve Seashells. Edinburgh.

212 pp. Second Edition. Evidently no changes, except for

four previously black-and-white plates now being in color.

This is really a second printing.

Narchi, Walter. 1974. Functional Morphology of Petricola

(Rupellarm) typica (Bivalvia; Petricolidae). Marine Biology,

vol. 27, pp. 123-129, 9 figs. Excellent.

Sandved, K. B. and R. T. Abbott. Sept. 1976. Shells in Color

112 pp., 101 colored plates. Viking Penguin Books,

Baltimore. Paperback, $4.95.

Leathem, Wayne and Don Maurer. Oct. 1976. Phylum

Mollusca: A Ouide to the Mollusca of the Delaware Bay

Region 43 pp., mimeographed. Contains list, keys and

bibliographies. $3.00. Publications Office, College of Marine

Studies, Newark, De. 19711.

Mayissian, S. 1974. Coquillages de No^ivelle-Caledonie et de

Melanesie. 72 pp., 28 colored plates. Privately printed, S.

Mayissian, Noumea. Sumptious.

Lefevre, George and W. C. Curtis. 1912 (1976 reprint). Studies

on the Reproduction and Artificial Propagation of

Freshwater Mussels. Bull. Bureau Fish., vol. 30, for 1910.

Softback reprint by Aurele La Rocque, Columbus, Ohio.

$4.00.

Pojeta, John Jr. and Bruce Runnegar. 1976. T^e Paleontology

of Rostroconch Mollusks and the Early History of the

Phylum Mollusca. U.S. Geol. Survey Prof. Paper 968, 88 pp.,

54 pis. $3.40. Four subphyla and eight classes of mollusks

are recognized. New are two families, six genera and 18

species in the fossil Rostroconchia.

Colloque International de Malacologie Marine Appliqee. 1976.

Haliotis, vol. 5, pp. 1-300. Research reviews on various aspects

of conchyliculture, pollution and commercial shellfisheries

in Europe.

Abbott. R. Tucker. 1975. Muscheln and Schnecken des Meeres.

Delphin Verlag, Stuttgart. German translation of Golden

Nature Guide, 1962.

Chen. T. P. 1976. Aquaculture Practices in Taiwan. 162 pp., 98

figs. Fishing News Books, Ltd., Surrey, England £2. Covers

culture of oysters, Meretrix, Anadara and Corbiatla, as well

as fish and frogs.

Dance, S. Peter. Nov. 1976. TTie Shell Collector's Guide, An In-

troduction to the World of Shells. 192 pp., 34 color pis., text

figs. Entertaining and well-done beginner's guide to con-

chology. David and Charles, London.

8 THE NAUTILUS

January 27, 1977

Vol, 91(1)

GROWTH OF THE FINGERNAIL CLAM, SPHAERIUM TRANSVERSUM (SAY)

IN FIELD AND LABORATORY EXPERIMENTS'

William F. Gale^^

Department of Zof)logy and Entomology

Iowa State University, Ames, Iowa 50010

ABSTRACT

Field and laboratoi-y experiments on Pool 19 of the Mississippi River in summer

and fall of 1967 revealed that S. transversum can complete its life cycle in about a

month or less. In laboratory experiments, many newborn clams entered a resting

state and did not grow for 33 days after they were bom; later, some grew large.

Medium-sized clams grew slowly but gave birth to young that often grew faster

and larger than their parents. In field experiments, clams that were moved from

an open-river site (where the clam poptdation was high) to a retainer in a cove

(ivhere the population was low) grew faster and became larger than those remain-

ing at the collection site; they also grew larger than clams in laboratory ex-

periments.

Fingernail clams were abundant in Pool 19 of

the Mississippi River during a 1966-68 survey of

the benthos. Densities of Sphaerium transversum

reached over 100,000/m' in some areas (Gale,

1969) in spite of heavy predation by leeches, fish,

and waterfowl. In autumn of 1967, diving ducks

harvested about 24% (2,085,125 kg) of September's

standing crop of fingernail clams (Gale, 1973;

Thompson, 1973). Life history data were collected

in an effort to determine the cause of the clam's

success. The objective in this study was to deter-

mine how fast S. transversum grows.

PROCEDURES

Growth experiments were conducted during the

summer and fall of 1967. Laboratory experiments

' Journal Paper No. J-7982 of the Iowa Agriculture and

Home Economics Ejcperiment Station, Ames, Iowa. Project

1373. A contribution from the Iowa Cooperative Fishery Unit

sponsored by the Iowa State Conservation Commission. Iowa

State University of Science and Technology, and the Fish and

Wildlife Service (U. S. Department of the Interior) (Contract

14-16-0003-12204),

' Present address: Ichthyological As.sociates, Inc.. Berwick.

Pennsylvania 18603.

' I thank Dr. Kenneth D. Carlander and Dr. R. Jess Muncy.

of the Department of Zoolog>' and Entomology, Iowa State

University, who directed the research and made many helpful

suggestions concerning the manuscript.

were conducted in a field laboratory above Ft.

Madison, Iowa (about 200 m upstream from the

Ft. Madison/Niota bridge). Water pumped from

near the river channel into the laboratory kept

temperatures and chemical conditions similar to

those in the river and provided clams with food.

Clams were housed in individual plexiglass

rearing chambers, 3.8 cm square and 5.0 cm deep

inside (Fig. 1, A); the upper 3.3 cm of the

chambers were covered on two sides with plastic

screen (mesh with 12 openings/cm) for water

passage. A set of nine rearing chambers was

placed in each of nine painted plywood compart-

ments (Fig. 1, B). A 5-cm baffle kept water levels

about 6 mm below the top of the rearing

chambers. Clams could not escape or move be-

tween chambers without crawling out of the

water.

Each rearing chamber contained about 10 cc of

strained clayey silt from the river bottom where

experimental clams were collected. Water in the

chambers was initially 3.5 cm deep but decreased

to about 2.5 cm as chambers silted in. Compart-

ments holding the chambers had a maximum

flush rate of 6 minutes; fluctuating pump

discharge and partial clogging of distribution tub-

ing reduced flushing rate.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 9

^L

^9,C.

41 CM

(" (' r' r' r' r' r'

SCREEN

^

PLEXIGLASS STRIP

4CM

I-4CMH

^BAFFLE

B

42 CM

X-

■^

t

+

+

FLOW

2ICM

-SPLASH BOARD

FIG. 1. Rearing apparatus. A, set of nine rearing chambers

(side view). B, compartment ivith rearing chambers in place

(top view).

TABLE 1. Reproduction and growth o/S. transversum in chambers in the laboratory between 21 July and 23 August. 1967. and

numbers present on November 7.5.

One large (over 10.0 mm long), two medium

(4.0-6.0 mm long) or four small (newborn) clams

were randomly assigned to each chamber; each

compartment had three chambers of clams of

each size group (chamber identification numbers

were adjusted for presentation in Table 1). Large

and medium-sized clams were collected in the

river, but small clams were born in the

laboratory. Small clams were removed with

camel-hair brushes (Thomas, 1959) within an hour

after their birth in pans of river water and

measured with an ocular micrometer. Larger

clams were measured with a vernier caliper;

damaged clams were discarded. Similar sized

clams were used as chambermates so that mark-

ing was unnecessary and handling was

minimized.

The laboratory growth experiment began July

21, 1967; after 33 days, 3 units were removed, the

27 chambers cleaned, and the contents screened.

Clams were measured as before and living ones

returned to their respective chambers (Table 1)

with fresh substrates.

To measure clam growth in the field, two re-

tainers with 80 clams each were submerged in

the river on July 6. One retainer was put in a

sheltered cove adjacent to emergent and

Chambers 7 and 8 were treated the same as 1-6 and 9, but are listed separately since the clams showed reproduction and more

growth. The clams with shells broken in handling on August 23 had not grown, nor had the dead clams in 1-6 or 19-27, but five

in 10-18 had grown 0.1 to 2.6 mm and one showed no growth.

10 THE NAUTILUS

January 27, 1977

Vol. 91 (1)

submergent vegetation (transect 5 station 2 of

Gale, 1969, p. 11) where there were less than 1,000

clams/m^; the other was placed in open water

(transect 4 station 14 of Gale, 1969, p. 11) where

there were about 42,000 clams/m^

Each retainer (Fig. 2, A) held 40 rearing tubes

(Fig. 2, B) suspended through holes in a plex-

iglass plate by aluminum rods. Rearing tubes

were 7 to 8 cm lengths of polyvinylchloride pipe

(I.D. 2.5 cm) with plastic screen attached near the

bottom: a painted wooden disk closed the lower

end of the screen. A tube like that in Figure 2, C

could be constructed and cleaned more easily.

Two randomly selected clams 5-7 mm long and

10 cc of strained clayey silt from station 14 were

placed into each tube. The retainer was then

forced into the river bottom until the two plex-

iglass flanges on the sides halted penetration

with the rearing tubes just above the substrate.

The retainer at station 2 was removed on

September 6. It had been turned over and many

tubes nearly filled wath mud. Tube contents were

screened and the clams counted and preserved in

PLASTIC TUBE

PLEXIGLASS

PLATE

FIG. 2. Rearing apparatus used in maintaining S. transver-

sum in the field. A, clam retaining apparatus: B, enlarged

side view of a rearing tube used in 1967: C, rearing tube with

alterations.

10% buffered formalin. Buoys marking the re-

tainer at station 14 disappeared by September,

and the retainer was lost.

RESULTS

Clam Growth in the Laboratory

Although the nine large clams stocked in

chambers 19-27 died shortly after the experi-

ment started, 53 young, 1.6-9.0 mm long

(Table 1), were produced (some may have been

second generation offspring). In only 33 days,

or less, one of the offspring had grown approx-

imately 7.0 mm in length (newborn clams in

Pool 19 average 2.2 mm long) (Gale, 1969) to

near maximum size.(S. transversum usually do

not exceed 12.0 mm in Pool 19, but clams up to

15.9 mm long and 8.1 mm thick were found.)

Reproduction in chambers 7 and 8, where

newborn clams had been stocked, demonstrated

that S. transversum not only could grow large in

a month but could complete its life cycle as well.

Many newborn clams, stocked in chambers 1-9,

had not grown by August 23 (Table 1) and some

of them did not move for several minutes after

removal from their chambers; some seemed dor-

mant (in a resting state). The periostraca of the

nongrowing clams were discolored and chalky.

Most of the 12 medium-sized clams that sur-

vived in chambers 10-18 grew slowly with a mean

length increase of 1.3 mm. Clam growth in

chamber 12 was not determined because five

clams exceeded the initial size of parental stock

and offspring and parents could not be

distinguished. In most instances, offspring of the

medium-sized clams grew rapidly and one was 9.0

mm long.

By November 15, when the chambers were

reexamined, reproduction had occurred in all but

two of the 27 chambers. Reproduction was max-

imum in chambers where one large clam had

originally been stocked (19-27) and one clam left

79 descendants. Many of the clams that seemed

dormant in August (chambers 1-9) had grovm to

9.0 mm or longer (Fig. 3). Most of the clams

stocked in chambers 10-18 had died without

reaching 9.0 mm, and many were smaller than

their offspring. Because observations of growth in

chambers 28-81 did little more than confirm

Vol. 91(1)

January 27, 1977

THE NAUTILUS 11

observations in chambers 1-27, precise data were

not collected.

In November the periostraca of nearly all

clams longer than 2.5 mm were speckled with

dark deposits and some were nearly black. S

transversum usually seems very clean, and it is

not known why deposits had accumulated on the

clams.

Clam Growth in Field Experiments

Clams grew well in the rearing tubes at station

2, and after 62 days, 45 were 4.0 mm or more

thick; the largest was 13.8 mm long and 6.6 mm

thick. Clams in the tubes were larger than those

living at station 14, the collection site (over 5,000

clams were examined there in mid-September but

none was 4.0 mm thick). That four clams in each

of 2 tubes were over 5.0 mm thick means that

within 62 days, one or both stocked clams grew to

maturity and discharged young that also had

grown large.

Clams in the tubes contained many embryos

and one large individual that seemed to have

given birth to 35 young (its chambermate had

died before reaching reproductive size) contained

86 embryos. A few of the 35 young may have

been second generation offspring.

A specimen of Sphaerium striatinum, placed

into a tube by mistake, had growm to a thickness

of over 4.0 mm but had not given birth.

Clams in 21 tubes were dead, perhaps from

senility, leech predation, or other causes (Gale,

1973). One live clam had a fungal growth nearly

covering outer portions of the inner gill; embr>'os

in the gill seemed unaffected.

DISCUSSION

In laboratory and field experiments, S.

transversum grew extremely fast and completed

its life cycle in about a month or less. Rapid

grow1;h has been noted for some other species of

Sphaerium. Sphaerium partumeium grew large in

7 to 10 weeks in laboratory experiments (Thomas,

1965) and gave birth when less than 14 weeks

old; clams grew even faster in the field. S. par-

tumeium (as M. partumeium) reared by Krull

(1936) grew to 4.5 to 5.0 mm long in about two

months and gave birth. Sphaerium corneum,

Sphaerium rivicola, and Sphaerium solidum

JUL. AUG ' NOV.

FIG. 3. Length changes in small and medium-sized S.

transversum in the laboratory, 1967.

suspended in baskets in the Elbe River grew

rapidly (Thiel, 1928, 1930), and some S corneum.

born in early summer, matured, gave birth, and

died that autumn.

If S. transversum in the natural environment

grew as rapidly as those in laboratory and field

experiments, several generations could be pro-

duced annually. At station 14, however, medium-

sized clams seemed to have grown only 2 mm

longer in July and 3 mm in August (Gale, 1972),

considerably less than those in growth ex-

periments. Clam grovrth may have been hindered

at station 14 by high clam density. Also, the

clams were probably debilitated by high infesta-

tions of larval trematodes (Gale, 1973).

Although clam growth rates in the laboratory

and at station 2 were similar, clams grew much

larger at station 2. Because parental stock of both

groups came from the same site and presumably

from the same genetic stock, some factor or fac-

12 THE NAUTILUS

January 27, 1977

Vol. 91(1)

tors in the laboratory seem to have stunted the

clams. Clams at some sites in the river did not

reach ma.ximum size either. Thiel (1928) observed

that 5. comeum in the Elbe River did not grow

to maximum size in "overpopulated" areas. The

fact that some medium-sized S. transvermm.

which did not grow much during the first :33 days

of the laboratory experiment, remained smaller

than their offspring in November (Fig. 3), sug-

gests that, once growth is arrested or retarded, it

is not completely compensated for later, when

growth conditions become favorable.

Why some clams had initial growth lags and

their chambermates did not is not clear, but

delayed growth does not seem to have been

genetically controlled (Gale, 1972). Delayed

growth may involve metabolic slowdown that

enables clams to bury themselves deep in the

substrate to escape predation, parasitism, or un-

favorable water conditions (Gale. 1973). In tem-

porary ponds in Michigan, Kenk (1949) found

that only fairly young Sphaerium ocddentale and

S. partumemm (as S. truncatum) survived the

dry period.

It is sometimes pointed out that fast growth is

of great advantage to inhabitants (such as some

fingernail clams) of temporary ponds, because

they can take advantage of a short growing

period. One might conclude that, through evolu-

tion and natural selection, the advantage of being

able to survive short growing periods has pro-

duced clams with tremendous growth rates. But,

the fact that S. transversum grows rapidly but

does not often inhabit temporary ponds, suggests

that other factors produced rapid growth. This

rapid growth may be a form of preadaptation.

That S. transversum may have originated in tem-

porary ponds and then moved to other habitats

merits consideration.

But, regardless of why S. transversum grows

rapidly, the fact that it can complete its life cycle

in about a month may be a major factor in its

success in Pool 19, where predation pressures are

great. If a population is to sustain itself under

heavy predation, quick growth and reproduction

would be advantageous, if not essential, for the

shorter the prereproductive period, the greater

the probability an organism has of reproducing

before being consumed.

LITERATURE CITED

Gale. W. F. 1969. Bottom fauna of Pool 19, Mississippi River

with emphasis on the life history of the fingernail clam,

Sphaerium transversnm. Ph.D. thesis. Iowa State Univ.,

Ames. Univ. Microfilm No. 69-20642. Ann Arbor. Mich.

Gale, W. F. 1972. Seasonal variability in calyculism in

Sphaerium transversum (Say). The Nautilits S6: 20-22.

Gale. W. F. 1973. Predation and parasitism as factors affecting

Sphaerium transversum (Say) populations in Pool 19,

Mississippi River. Res. Popul. Ecol. 14: 169-187.

Kenk. R. 1949. The animal life of temporary and permanent

ponds in Southern Michigan. Misc. Publ Mus. Zioi. Univ.

Mich. 71: ,5-66.

Krull. W. H. 19136. Raising Musculium partumeium (Say)

under laboratory conditions. Papers Mich. Acad. Sci. Arts,

ami Letters 21: ^35-638.

Thiel. M. E. 1928. Zur Biologie unserer Siisswasser-muscheln.

Z Mnrphol Okol. Tiere 13: 65-116.

Thiel. M. E. 1930. Untersuchungen liber den Einflti-ss der Ab-

wasser von Hamburg-Altona auf die Verbreitung der Arten

der Gattung Sphaerium in der Elbe bei Hamburg. Int. Rev.

gesam. Hydrobiol. Hydrogr. 24: 467-484.

Thomas. G. J. 19.59. Self-fertilization and production of young

in a sphaeriid clam. The Nautilus 72: 131-140.

Thomas. G. J. 1965. Growth in one species of sphaeriid

clam. The Nautilus 79: 47-54.

Thompson. .1. D. 1973. Feeding ecology of diving ducks on

Keiikuk Pool. Mississippi River. Jmir. Wikil. Manage. 37:

:i67-:3Kl.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 13

THE FORMATION AND STRUCTURE

OF THE SHELL VARIX IN STAGNICOLA ELODES (SAY)

(GASTROPODA: LYMNAEIDAE)

Eileen H. Jokinen

Biology Department

Suffolk University

Boston, MA. 02114

ABSTRACT

A life history study carried out in 1970-71 on a population of Stagnicola elodes

in a temporary pond in lower Michigan reveals that a varix is laid damn at the

cessation of a period of shell growth which may or may not be followed by a

period of dormancy. The adult snails of the Michigan population have 2 varices,

one deposited before estivation of the juvenile snail, the other deposited after adult

spring growth. It appears that the number of varices cannot be used to estimate

the age of the snails unless the annual life cycle and environmental conditions are

examined.

The microstructure of the varix was determined by microscopic examination of

acetate peels of shell sections made at right angles to the varix. The varix is

fonned from greatly elongated (.5-6X normal) crystals of the prismatic layer. The

probable function of the varix is to add strength to the outer lip.

INTRODUCTION

The freshwater snail Stagnicola elodes (Say)

periodically puts down additional shell material,

the varix (Baker, 1911), on the inside of the outer

lip. In S. elodes the varix is purple-brown in col-

or and parallels the outer lip. In Baker's opinion,

varices, normally three in number in Lymnaea

palustris ( = S. elodes), mark periods of "hiberna-

tion" when the animal is "buried in

mud" and do not represent annual growth mark-

ings. However, Baker was not positive of this in-

terpretation.

DeWitt (1954) reports that when "growth in

Physa gyrina is interrupted for some reason, the

inner edge of the outer lip of the aperture is

strengthened by a triangular thickened band . . .

Conditions which arrest growth and lead to for-

mation of these bands are obscure; production

does not appear to be dependent upon en-

vironmental factors, rather they are a result of a

physiological pattern developed within the species

and perhaps modified to some extent by environ-

ment." DeWitt states that the bands might be ac-

counted for in terms of periodic drying of the

habitat but felt it unlikely that such a thickening

would be produced under adverse conditions of

drought or estivation. Herrmann & Harman

(1975) believe that varices in Helisoma anceps

(Menke) reflect slow winter growth.

FIELD OBSERVATIONS

During 1970-71 a study was carried out on the

life history of a population of Stagnicola elodes

(Say) in a woodland pond in the Pontiac Lake

Recreation Area, Oakland County, Michigan. The

annual life cycle begins in May when eggs are

laid. Egg laying continues through July. The new-

ly hatched generation feeds until the snails reach

2-7 mm in length. At this point the young cease

growth and actively leave the water to estivate

on grasses and tree trunks above ground. The ma-

jority of the older snails follow the receding pond

water to become stranded on the dry pond floor

and there be preyed upon, most commonly by

sciomyzid (Diptera) larvae. The young estivating

snails eventually leave their above-ground loca-

tions and come to lie under the pond leaf litter to

14 THE NAUTILUS

January 27, 1977

Vol. 91(1)

over-winter. TTie immature snails (mean shell

length = 8 mm) become active in the spring as

soon as the ice melts. The snails grow rapidly so

that by June the mean shell length is approx-

imately 15mm (Jokinen, in prep.).

The snails of the Michigan population of S.

elodes were noted to deposit several varices dur-

ing their life times. In 1970, varices on the outer

lips were first noted on July 12 on 4 snails (shell

lengths from 10.3 to 21.7 mm) out of 123 (3.3%).

Egg masses were in evidence by this date. By Ju-

ly 26, 13 out of 121 snails (10.7%) had varices. On

August 9, estivating immature snails were first

observed and noted to have varices (100%). In

1971, 5 snails were collected from under the ice

in February and March. The snails ranged from

3.7 mm to 11.8 mm and all 5 had varices on their

outer lips. On April 20, 1971, 34 snails were col-

lected. The winter varix was evident on all of the

snails, and 32 had new, fragile, and thin shell

growth beyond the varix. The mean linear incre-

ment of new growth beyond the varix was 1.5

mm (range .2-3.5 mm). Shell growth was rapid

during May and egg masses appeared by the end

of the month. By June 6, the entire sample

population of 153 snails (except one) had

deposited new varices.

MICROSCOPIC STRUCTURE OF THE VARIX

In order to determine the structure of the

varix of S elodes, a portion of shell was cut at

right angles to the aperture, so that the section

was at right angles to the length of the varix

(Figure 1). Acetate peels were made from

polished shell sections following the method of

Boardman & Utgaard (1964).

a: PLANE OF

FIGURE 2

VARIX

FIG. 1. Locaticn of the varix in Stagnicola elodes (Say).

FIG. 2A. Acetate peel of a polished shell section cut at right

angles to the varix. The normal shell iMth i's demonstrated

in the tipper portion of the photograph. The thicker portion is

the varix. p., peroist racum : 1.1., longitudinal lamellar layer;

c.1.1, first crossed lamellar layer; c.1.2, second crossed

lamellar layer; pr., prisniatie layer.

FIG. 2B. 7.5X magnification of the area between the arrows

of A. There are two layers of periastracum and a space

beneath the periostracum. p., periosiranim ; I.I., longitudinaJ

lamellar layer; c.1.1, first crossed lamellar layer; pr.

prismatk layer. (?50x total magnificatian).

According to Boggild (1950), the calcareous por-

tion of the shell of Stagnicola pitluxtriit (= S.

elodes) is composed of aragonite deposited in four

distinct layers. The shells of S. elodes from

Michigan were examined and found to also

possess four calcareous layers arranged as

follows: (1) a very thin outer longitudinal

lamellar layer under the periostracum; (2) a

crossed lamellar layer; (3) a prismatic layer; and

(4) a second crossed lamellar layer (Figure 2). As

illustrated, the varix is formed by an increase in

the length of the crystals of the prismatic layer.

The crystals are approximately 5-6 times as long

Vol. 91(1)

January 27, 1977

THE NAUTILUS 15

in the varix as in the normal shell. Gross ex-

amination of a ground section demonstrates that

the purple-brown color of the varix is due to

streaks of pigment laid down in the thickened

prismatic layer. The thickened outer lip of

mature Helix IThebnl pisana MUller is also formed

by elongated prismatic crystals (Matthes, 1914).

CONCLUSIONS

Field evidence shows the pattern of varix

deposition to be associated with cessation of

growth. Snails without a varix were rapidly

growing individuals, including the newly hatched.

Snails with a terminal varix were estivating

juveniles, overwintering individuals, and egg-lay-

ing adults which had completed their spring

grovrth. The varix is laid down at the end of a

period of growth and not during a period of dor-

mancy. Therefore, the number of varices cannot

be used to estimate the age of snails unless the

annual life cycle and environmental conditions

are examined.

The number of varices in adult snails will dif-

fer, depending upon annual activity. If a pond

dries up in summer, gains water again before

temperatures become too cold for gastropod ac-

tivity, and then warms up again the following

spring, breeding adult snails will have 3 varices;

two representing periods of pre-dormancy and

one the termination of growth before egg deposi-

tion. This is probably the situation observed by

Baker (1911) who found 3 varices normal for L.

palustris (= S. elodes), one varix on the third

whorl, one on the fifth, and a third on the aper-

tural lip of the adult.

The snails from Michigan all had a varix inside

the outer lip in early spring before the ice

thawed. In this case the summer-fall estivation,

marked by a varix on the juveniles, had con-

tinued into the overwintering period, the pond

not refilling until freezing temperatures had ar-

rived. Therefore, the snails were not given the op-

portunity to renew growth in the fall. After the

pond thawed and the water warmed, new shell

material was rapidly laid dovm, the pur-

ple-brown color of the summer-fall varix mark-

ing the initiation of dormancy. By June the

snails had grovra considerably in length and the

new shell growth was very thin. Then linear

growth slowed, the new shell material thickened

and another varix was deposited. Under such con-

ditions an adult snail will exhibit only two

varices.

Microscopic examination suggests that the

varix adds considerable strength to the shell lip

as is the case with the shell lamellae found in

Biomphalaria (Richards, 1964). It is doubtful that

the varix would protect against desiccation since

it extends into the shell aperture only a short

distance. A likely function would be to

strengthen the shell lip and thus protect against

breakage between f)eriods of growth, whether or

not the snails are active.

ACKNOWLEDGEMENTS

I wish to express my sincere gratitude to Dr.

David R. Cook for his advice and encouragement.

Dr. Osborn B. Nye for technical instruction, and

Dr. Peter H. Rich for critically reviewing the

manuscript. Preparation of the manuscript was

aided by the facilities of the Biological Sciences

Group at the University of Connecticut.

LITERATURE CITED

Baker, F. C. 1911. The Lymnaeidae of North and Middle

America, recent and fossil. Spec. Publ. No. 3. Chicago Acad.

Sci.

Boardman, R. S. & Utgaard, J. 1964. Modifications of study

methods for Palezoic Bryozoa. J. Palemit. 38:768-785

Boggild, 0. B. 1930. The shell structure of the mollusca. K.

danske Vidensk. Selsk. Skr., Natunndensk. math. Afd. (9)

2(2):231-3a5

DeWitt, R. M. 1954 Reproduction, embryonic development

and growth in the pond snail Physa gyrina Say. TVans.

Amer. Micros. Soc. 73:124-137

Herrmann, S. A. & Harman, W. N. 1975. Population studies

on Helisoma anceps (Menke) (Gastropoda: Planorbidae).

A'ojrfi7jis89(l):5-ll

Jokinen, E. H. (in prep). Estivation in Stagnicola elodes (Say)

(Gastropoda: L>Tnnaeidae).

Matthes, W. 1914. Beitrage zur Anatomie von Helix pisana

Mull. Je«a Z. Naiiirwiss. 53: 1-.50.

Richards, C. S. 1964. Apertural lamellae as supporting struc-

tures in Australorbis glabrattis (Say). The Nautilvs 78:

57-60.

16 THE NAUTILUS

January 27. 1977

Vol. 91 (1)

PREDATION BY WINTER FLOUNDER

(PSEUDOPLEURONECTESAMERICANUSJ

ON THE SIPHONS OF THE CLAM, TELLINA AGILIS

William H. Gilbert >

Department of Biology

Colby College

Waterville. Maine 04901

and Ellen F. Suchow

Belle W. Baruch Institute

University of South Carolina

Columbia, South Carolina 29208

The bivalve Tellina agilis Stimpson commonly

inhabits marine, shallowwater, sand-mud

sediments (see Maurer, et ai, 1974). These small

clams (max. length = 1.6 cm) burrow 1-3 cm into

the sediment and deposit -feed on the sediment

surface with separate, extensible, inhalent

siphons (Gilbert, 1970), movements of which may

attract visual predators such as the commercially

important winter flounder, Psendopleuronedes

americanus (Walbaum). Edwards, et al. (1970)

have shown that small flounder, Pleumnectes

platessa (L.), in Scotland obtain a large part of

their food by preying on siphons of Tellina tenuh

da Costa, which can regenerate their siphons. The

aim of our study was to seek evidence that small

winter flounder prey on siphons of T. agilis in

nature.

Eight winter flounder (lengths = 4-6 cm) were

collected (27 September 1969) at the mouth of

Barnstable Harbor (Cape Cod Bay),

Massachusetts. The fish were captured by hand

net during the flooding tide on a sand flat 0.5 m

above mean low water. An abundant population

of T. agiUs (100-600/m^) occurred on the flat, but

other clams with similar siphons (e.g., Cumingia,

Macoma, and Petricola) were rare or absent (see

Edwards, 1975). The fish were placed immediately

in 95% ethyl alcohol to terminate digestion, and

stomach contents were examined later in the

laboratory.

Stomachs of four of the eight fish contained 1-3

siphon fragments (9 total). These fragments and

intact siphons of T. agilis collected at the site had

similar measurements (made at 7X power with

an eye-piece micrometer) for total width, width

of circular muscle bands, and width of

longitudinal bands (Fig. 1). The length of an ex-

tended siphon is 3-4 times shell-length; the

fragments ranged from 0.5-2.5 mm in length and

were usually identifiable as the siphon tip.

Levinton (1971; Levinton & Bambach, 1975)

report that Macoma tenia (a subtidal clam)

deposit-feeds on detritus at night when its

siphons are not visible to fish predators, but that

T. agilis deposit-feeds on benthic diatoms during

the day. Many benthic diatoms concentrate dur-

ing the day at the sediment surface, which turns

a golden-brown hue as a result (Sanders, et al.,

1962). Thus the efficiency of daytime grazing by

T. agilis may outweigh the hazard of exposing

siphons to fish predators.

In the laboratory, we observed the behavior of

a small winter flounder placed in a water tank

with a tray of sediment containing several live T.

agilis. On two occasions, the fish uncovered clams

by lunging at the sediment surface where siphons

were deposit-feeding. When each clam attempted

to burrow back into the sediment, the fish took a

bite out of its foot.

' Present address: Environmental Studies Program, Ottawa

University, Ottawa. Kansas 66067.

FIG. 1. Intact .-tiphim of a Tellina agilis (shell-length = 1.0

cm) in .W/o ethyl alcohol.

Vol.91 (1)

January 27, 1977

THE NAUTILUS 17

Martin (1940) reports that T. agilis (as T.

tenera) is an intermediate host for Monorcheides

cumingiae, a parasitic trematode which encysts

(as metacercariae) in siphon and foot tissues of

the clam. Martin fed infected clams to eels and

flounders (species unspecified) and obtained adult

Monorcheides later from intestinal mucusa of the

fish. Our observation that small winter flounder

prey on T. agilis suggests that these fish might

take in Monorcheides. Further studies are needed

to determine (1) whether or not winter flounder

is a definitive host for this parasite, and (2) the

importance of T. agilis siphons in the diet of

young winter flounder.

We thank Drs. D. C. Edwards, J. S. Levinton,

and F. J. Vemberg for their comments about this

manuscript.

LITERATURE CITED

Edwards, R. R. C, J. H. Steele, and A. Trevallion. 1970. The

ecology of 0-group plaice and common dabs in Lock Ewe.

III. Prey-predator experiments with plaice. J. Exp. Mar.

fto/.£coU: 156- 173.

Gilbert, W. H. 1970. Territoriality observed in a population of

Tellma agilis (Bivalvia: MoUusca). Biot. Bvll 139:423-424

(abstr.).

Levinton, J. S. 1971. Control of tellinacean (Bivalvia:

MoUusca) feeding behavior by predation. Limnol. Oceanogr.

16:660-662.

Levinton, J. S., and R. K. Bambach. 197.5. A comparative

study of Silurian and Recent deposit-feeding bivalve com-

munities. Paleobiology 1:97-124.

Martin, W. E. 1940. Studies on the trematodes of Woods Hole.

III. The life cycle of Monorcheides cumingiae (Martin) with

special reference to its effect on the invertebrate host. Biol.

Bull. 79:131-144.

Maurer. D., L. Watling, and G. Aprill. 1974. The Distribution

and Ecology of Common Marine and Estuarine Pelecypods

in the Delaware Bay area. The Nautilus 88: 38-45.

Sanders. H. L.. E. M. Goudsmit, E. L. Mills, and G. E. Hamp-

son. 1962. A study of the intertidal fauna of Barnstable

Harbor, Massachusetts. Limnol. Oceanogr. 7:63-79.

ECOLOGY OF THE SNAIL, MELANOIDES TUBERCULATA (MULLER),

INTERMEDIATE HOST OF THE HUMAN LIVER FLUKE

(OPISTHORCmS SINENSIS) IN NEW ORLEANS, LOUISIANA

Dee S. Dundee and Anna Paine

Department of Biological Sciences

University of New Orleans, Louisiana 70122

ABSTRA(Jr

The habitat and associates of a series of populations of the prosobranch snail,

Melanoides tuberculata (Thiaridae) introduced to a drainage canal in New

Orleans, Louisiana, are described. These snails, and associated fish, could serve

as intermediate hosts of the Chinese Liver Fluke, Opisthorchis sinensis.

In the spring of 1975, two populations of

Melanoides tuberculata (Miiller) (Thiaridae) were

discovered in New Orleans, one in the People's

Avenue Canal, Orleans Parish, and the other in

the canal on the neutral ground of General

DeGaulle Drive, Jefferson Parish. A third popula-

tion has recently been reported to us in 1975

from the west Metairie canal in Jefferson Parish.

This oriental prosobranch had previously been

reported from two localities in Texas (Murray,

1964; Murray and Wopschell, 1965), one in

Arizona and another in Oregon (Murray, 1971).

Abbott (1973) summarized its spread into Mexico

at Vera Cruz and in Panama and Puerto Rico.

The role of M. tuberculata as an intermediate

host in the life cycle of the Chinese Liver Fluke,

18 THE NAUTILUS

January 27, 1977

Vol, 91(1)

LAKE PONTCHARTRAIN

lEGEM:

CANALS

PIPE LINES

JTyPT AREA

SrHESTS

PUUPING STATIONS

! 1 i I f 1 I !

MALE M METIM

FIG. 1. A portion of the New Orleans drainage system in rela-

tion to the Peopk's Avenue carud.

Opisthorchis sinensis, makes the occurrence of it

in the U. S. of more than casual interest.

This study was done in a section of People's

Avenue Canal which is part of the New Orleans

storm drainage system. Since this city is largely

below sea level, drainage is accomplished by pump-

ing stations at intervals in the drainage canal

network (Fig. 1). This locality (Fig. 2) is per-

manently supplied with slightly brackish water

from a 600' well tapped by American Standard

Co. for use as cooling water in their air condi-

tioning system.

THE HABITAT

The reported habitat of Melanoides tuberculata

elsewhere in the U. S. is freshwater springs with

a pH of 7.0-7.5, a water temperature of 18-25° C,

and soft mud or gravelly-mud bottoms (Murray,

1971). The People's Avenue habitat is similar to

this. With few exceptions the stream bed is 50-70

cm wide and 10-40 cm deep. The flow during the

study was 42-51 cm/sec. Once we noticed a brief

threefold flow increase, from an unknowoi source.

At this time the level in the basin at the north

end rose 20 cm in a five minute period. The non-

vegetated bottom is sandy with scattered pebbles

and shells of Ravgia cuneata, a brackish -water

mactroid clam which is used for gravel. Few

Melanoides are found in this type of bottom.

Flow is much slower and the accumulation of silt

and detritus much greater behind the overhang-

ing stems and protruding roots of the bank

vegetation. This seems to be the prime

Melanoides microhabitat, supporting up to 251

snails/sq. ft. (2700/m^).

The canal banks are covered with vegetation.

The predominant cover is a prostrate species of

medium-height grass (probably Eragrostiit) with

Tifpha and Lysimachia constituting most of the

rest of the cover. The grass and Lysimachia are

IQ

8

<o

9

>o

en

z

I

r

20

30

I

LENGTHimm)'

FIG. 2. Histogram shounng population aye groups in the spring of 1975.

mill IIIL^iiiik..

40

Vol. 91(1)

January 27, 1977

THE NAUTILUS 19

ES.

AA4

■ ■■■

b rrggi

1 ♦

2 X

AAA

All

7AV I —

ot

n , smsh

AAA

AAA

-> 8 X

9 X

drain

pipe

10 A

11 A

■ ■■■

■ pipe IXIII

■over canal ■

12 A

aaAa

E N

AAAA

_D

23

scale in meters

FIG. 3. Diaymm of People s Avenue Canal showiny di.

the only plant species directly in contact with

Melanoides. At the stream bank they create the

sheltered environment that Melanoides seems to

prefer. Other plants in the area are: Polygonum

sp., Spartina altemiflora, Phragmites communis,

and Sagittariafalcata.

Animal species associated with Melanoides at

this site include insects (Ranatra and Pelocoris,

both predaceous hemipterans; Chironomidae,

dipterans), crayfish, oligochaetes, and fishes

(Poecilia latipina and Heterandria formosa). The

fishes are of particular interest since various

poecilids are known to be second intermediate

hosts for Opisthorchis sinensis, the human liver

fluke which has Melanx)ides tuberculata as its

first intermediate host.

POPULATION SAMPLINGS

Square foot (.093 m) quadrat samples were

taken starting from the northernmost end of the

canal (Fig. 3) at 46-meter intervals downstream

(12 stations in all) to the point where the canal

turns westward and goes underground. Two

samples were taken at each station, at opposite

banks just underwater and at the surface. In-

dividuals were returned to the lab, counted,

measured, and whorl counts made. Histograms

were then plotted from these data for each sta-

tion. The population for September-October 197.5

follows a normal curve pattern with a few young

of 10 mm and 8 whorls, a few older individuals of

44 mm and 14.5 whorls, and the bulk of the

population in-between. The best-represented size

class is 25 mm long with 12 whorls. Fig. 2 is a

histogram of the snail total lengths— lumping all

Uribii tlon ofsnails in relation to substrate and vegetation.

of the stations (656 individuals) to present an

overview of the population. The histogram

will doubtlessly shift considerably during

reproductive seasons. Only one cluster of young

was found indicating that late summer is not a

major reproductive season for these live-bearers

here. A parthenogenetic mode of reproduction has

been reported tor Melanoides (Jacob, 1957).

TABLE 1. The range of physico-chemical values encountered

for each parameter.

The flow from the well is 4500 liter/min. This

water has some interesting properties related to

its origin. The usual alkalinity values en-

countered for Lake Pontchartrain are in the

30-50 ppm range; free CO2 is generally less than

5 ppm. At the pH values we recorded, carbonate

ion is absent; the high CO2 and alkalinity values

are what might be expected for a subterranean

water source that is far from being in

equilibrium with the atmosphere. The low

dissolved oxygen content (saturation at 25° C is

8.1 ppm) also suggests this water is recovering

from subsurface conditions. All these water quali-

ty parameters may have been affected by passage

20 THE NAUTILUS

January 27, 1977

Vol. 91 (1)

through the American Standard Company air

conditioning system. The slight brackishness of

this water is usual for southeastern Louisiana

waters and does not seem to inhibit Melanmdes.

SIGNIFICANCE

The introduction of Meldmildpn tuberrulntd in-

to an area where poecilid fishes occur plus the

fact that Vietnamese people are being settled

nearby could be highly significant, particularly if

some of these people are infected with trematodes

and if they are still including raw fish in their

diet. It is not known at the time of this writing

whether the incoming Vietnamese were screened

for liver flukes. Since all of the ingredients for

the Opi.'^thorchut life cycle might now be present,

it is important that we learn more about the

snail and continuously monitor the spread of it.

ACKNOWLEDGEMENTS

We wish to thank Dr. Harold Murray of Trini-

ty University for verifying our determination of

the snails. Voucher specimens have been

deposited in the Delaware Museum of Natural

History, No. 113847. Also the following Univer-

sity of New Orleans graduate students were

equally responsible for the results of this study:

Bill Copeland, Tom Chin, Ben Garrett, Cheryl

Noble, Mike Rayle and Mary St. Martin.

LITERATURE CITED

Abbott. R. T. 1973. Spread of Melanmdes tuberculata. The

.V(iM/i7».s87(l):29.

.lacub. .J. 19.57. Cytological Studies of Melaniidae (Mollusca)

with Special Reference to Parthenogenesis and Polyploidy.

I. Oogenesis of the Parthenogenetic Species of Melanoides

(Prosobranchia-Gastropoda). Trans. Roy. Soc. Edinburgh

63: *1 1-3.52.

Murray, Harold D. 1964. Tarebia granifem and Melanoides

tuberculata in Texas, (an abstract). Ann. Reports Amer.

Malacol. Union, 15-16.

Murray, Harold D. 1971. The Introduction and Spread of

Thiarids in the United States. The Biologist 53(3): 133- 135.

Murray, Harold D. and Leon J. Wopschell. 1965. Ex»logy of

Melanmdes tuberculata (Miiller) and Tarebia granifera

(Lamarck) in South Texas (abstract). Ann. Reports Amer.

Malacol. Union, for 1965, pp. 25-26.

NEW RECORDS AND ECOLOGICAL NOTES FOR CORBICULA

MANILENSIS IN TEXAS

Joseph C. Britten and Clifford E. Murphy

Department of Biology

Texas Christian University,

Fort Worth, Texas 76192

ABSTRACT

Corbicula manilensis is distnbuted through seven major drainage systems in

Texas. Potential mechanisms of dispersal are discvssed. The species seem to prefer

sandy substrates in Texas reser^wirs but occm's in a variety of bottom types.

Specimens of Corbicula have been removed from stomachs of three species of

yis/i— Lepomis microlophus, Minytrema melanops and Aplodinotus grunniens.

The first reports of Corbicula manilensis in

Texas were from the western portion of the state

(Metcalf, 19(56 and Metcalf and Smartt, 1972).

Murray (U)71) discusses the presence of Corbicula

in S(juth Texas and notes its eastward progres-

sion from the Rio Grande drainage to Lake Cor-

pus Christi, 25 miles north of Corpus Christi. He

also reports large populations of the Asiatic clam

from Lake LBJ in the Colorado River drainage of

Central Texas (Murray, 1972).

Corbicula was reported in Ijouisiana waters as

early as 1961 (Dundee and Harman, 1963). Con-

sidering its rapid range expansion in other parts

of the United States, it is interesting that no

Vol. 91 (1)

January 27, 1977

THE NAUTILUS 21

reports of Corbicula in eastern Texas have yet ap-

peared in the literature. It seems inevitable,

however, that the eastern and western popula-

tions of Corbicula will finally converge in this

state.

We have compiled a list of new distributional

records of Corbicula in central, northeastern and

eastern Texas. The first record of the species in

northeastern Texas was from Lake Grapevine

(Tarrant County), a reservoir of the upper Trinity

River drainage. Mr. Donnie Roberts provided the

senior author with several specimens collected

from Lake Grapevine in November, 1972. Subse-

quently, several reservoirs in Tarrant County

were found to harbor Corbicula populations. The

authors recovered specimens from Lake Arlington

on January 21, 1974; from Lake Benbrook on

February 3, 1974; and from Eagle Mountain Lake

in September, 1974. In August, 1973, the senior

author collected a specimen from the Colorado

River at Marble Falls in central Texas.

During October and November, 1974, and

March and April, 1975, the Texas Christian

University Research Foundation provided finan-

cial support which enabled us to briefly survey a

number of Texas reservoirs east of the Colorado

River system. We visited Possum Kingdom

Reservoir (Brazos River drainage). Lake Play

Hubbard, Navarro Mills Reservoir, C«dar Creek

Reservoir, and Lake Livingston (Trinity River

drainage). Lake Conroe (San Jacinto River

drainage). Lake Tawakoni (upper Sabine River

drainage). Diversion Lake, Lake Wichita, and

Lake 0' the Pines (Red River drainage), and

Lake Sam Rayburn and Steinhagen Reservoir

(Neches River drainage). Most of the surveys

were not exhaustive (exceptions were those at

Possum Kingdom, Diversion Lake and Lake

Wichita) so the failure to detect Corbicula at a

locality does not necessarily indicate the absence

of the species in an area. In fact, only Lake Sam

Rayburn and Lake Texoma yielded specimens.

The Rayburn specimens were collected from a

sandy substrate on the northwestern shore of the

lake on October 18, 1974, whereas specimens from

Lake Texoma were taken from sand along the

northern shore of the lake near the University of

Oklahoma Biological Station on April 24, 1975.

Harold Murray has provided additional

distribution data from central Texas. He has

received specimens collected by Emily Mims from

Lake Buchanan on June 30, 1973. On September

21, 1973, the ecology class of Trinity University

recovered Corbicula from Canyon Lake,

Guadalupe River. Scott Horn provided Murray

with specimens collected on September 8, 1974,

from the Guadalupe River below the dam at

Highway 90 and 90A near Seguin, Texas.

Ray Dinges of the Texas Water Quality Board

has provided us additional records. He has col-

lected Asiatic clams from Lake Austin on the

Colorado River, along the Colorado River between

Austin and Bastrop, and in the Nueces River

along Texas Farm Road 1025, north of Crystal

City.

The known distribution of Corbicula in Texas

now includes seven major drainages: the Rio

Grande, Nueces, Guadalupe, and Colorado Rivers,

with dispersal apparently occurring within these

systems generally from west to east, the upper

Trinity River drainage and the Red River

drainage with populations recruited from an

uncertain source, and the Neches River drainage

with this population possibly recruited from

Louisiana (see Figure 1). Considering the ap-

parent lack of Corbicula populations immediately

adjacent to the upper Trinity River assemblage,

it seem possible that the species gained access to

FIG. 1. The knoum distribuiion of Corbicula manilensis in

Texas through April 1975.

22 THE NAUTILUS

January 27, 1977

Vol. 91 (1)

10

15

20

25

30

SHELL LENGTH (mt)

FIG. 2. Size frequency di.ftrihulidii of a nindom sample nf

paired rnlres of Corbicula manilensis collected from Lake

Benhrook. Texas. November. l!)7Jt.

North Texas waters as a result of introduction

from a remote source. Many live-bait

establishments obtain minnows from Arkansas or

Louisiana, transporting several hundred gallons

of water with each shipment of minnows.

Perhaps Corbicula larvae may have been

transported with this water. Fisherman could

just as likely bring an establishing population in-

to the area in a live-bait hold of a boat. The pat-

tern of distribution of Corbicula in Texas is

decidedly trending along a roughly north to south

axis. This fact may be due only to coincidence,

but since it parallels closely a migratory bird

flyway, it may suggest an alternative dispersal

mechanism.

From whatever source that Corbicula became

established in Tarrant Cbunty reservoirs, it is

certain the Asiatic clam is firmly entrenched

there. In 1973, Britton, Murphy, Keith and

Mauldin completed a study of the bivalve fauna

of Tarrant County Reservoirs. From June 1971 to

August 1972, extensive bivalve collections were

made in Benbrook and Eagle Mountain reser-

voirs. At that time there was no evidence of Cor-

bicula in either lake. By November 1974, shell

debris accumulations of Corbicula along portions

of the western shore of Benbrook Lake yielded

densities in excess of 800 valves per foot. A ran-

dom sample of 140 paired valves was taken from

this shell debris material. Measurements were

made of each individual in the sample. The

length of the largest was 30.4 mm. A frequency

distribution of length or height measurements ob-

tains a distinctly bimodal curve, suggesting two

major age classes among the Benbrook Corbicula

population (Figure 2). This correlates well with

the time available for the species to have become

established.

Considering the rapid spread of Corbicula in

southwestern Texas and among the Tarrant

County reservoirs, it is interesting that the

species apparently has not yet entered the Brazos

River system (or, at least the upper Brazos from

Possum Kingdom Reservoir to Waco, Texas). In

the summer and fall of 1974, we made extensive

collections of bivalves from Possum Kingdom

Reservoir during a period when the lake was

significantly below normal. Corbicula was never

observed. In addition, Mr. Chuck Fontainer has

been intensively studying unionid populations in

the Brazos River near Waco. He has employed

numerous collecting techniques including SCUBA

diving to recover clams. To date he has not en-

countered Corbicula in the Waco area. The

Brazos drainage should be monitored closely dur-

ing the next few years, as it is the only major

river system between western and eastern Cor-

bicula populations which still lacks the species.

The substrate preferences of Corbicula in Texas

are variable. We have taken the species from san-

dy gravel, sandy mud and muddy sand, and from

deeper water muds. The most abundant popula-

tions seem to be on or in sandy or muddy sand

substrates. Clams can be found on the surface of

the substrate or buried as much as two cen-

timeters below the surface. At Sam Riiyburn

Reservoir we found a population of Corbicula in

a muddy sand substrate. The clams were approx-

imately 2 cm below the surface, but produced a

hole which emerged at the sandy water-substrate

interface for water currents to enter the mantle

cavity. The origin of this tube is curious, as the

siphons of Corbicula are too short to be extended

2 cm to the surface to produce it. Although we

have tried to reproduce the situation with

laboratory specimens, we have not been suc-

cessful.

The largest concentrations of Corbicula have

been collected from shore to depths of about 8

Vol. 91 (1)

January 27, 1977

THE NAUTILUS 23

feet. Living specimens have been recovered by

dredging in silty substrates in Lake Benbrook at

a depth of approximately 20 feet.

Our students have removed Corbicula from

stomachs of three fish species from North Texas

waters. A red ear sunfish, Lepomis microlophuii,

from Lake Benbrook was found to contain Cor-

bicula shells up to 5 mm in length. A spotted

sucker, Minytrema melanops. from the same lake

had ingested shells up to 3 mm in length. From

Eagle Mountain Lake a freshwater drum,

Aplixiinotus gmnniens. had five specimens of

Corbicula in the gut ranging from 3 to 5 mm in

length.

LITERATURE CITED

Britton, Joseph C. C. E. Murphy, D. E. Keith, and Virginia

Mauldin, 1973. A quantitative and (jiialitative survey of the

plankton and benthic invertebrates including bivalves of

Eagle Mountain and Possum Kingdom Lakes Part III,

Bivalves Texas Electric Service G)mpany Research Report

178. 101 pp.

Dundee, D. S. and W. J. Harman. 196."!. Oirbicula fluminea

(Mailer) in Louisiana. The Nauiduii 77(1): 30.

Metcalf. Artie L., 1966. Corbicula manilensia in the Mesilla

Valley of Texas and New Mexico. The Nautilus 80(1 ): 16-20.

Metcalf, Artie L. and Richard Smartt, 1972, Records of in-

troduced mollusks: New Mexico and western Texas. The

A^aM/i7«s 85(4): 144-145.

Murray. Harold D., 1971. New records of Corbicula manilensis

(Philippi) in Texas. The Nautilux 85(1): 3.5-36.

Murray. Harold D.. 1972. Freshwater mussels in Lake LBJ,

Te.\as. Bulletin of the American Malacological Union for

1971, pp. .36-37.

Sinclair, Ralph M., 1971. Annotated bibliography on the exotic

bivalve Corbicula in North America. 1900-1971. Sterkiana

43: 11-18.

OPISTHOBRANCHS FOUND OFF LITTLE EGG INLET, NEW JERSEY,

WITH NOTES ON THREE SPECIES NEW TO THE STATE

Elizabeth V. Carlo

Ichthyological Associates, Inc.

Box 70-D, R. D. 2, West Brook Lane

Absecon, New Jersey 08201

ABSTRACT

An intensive ecological survey in the incinity of Little Egg Inlet, New Jersey

found three species of opisthobranchs which are new to New Jersey (Pleurobran-

chaea tarda, Onchidoris bilamellata, and Facelina bostoniensis) and southern

range extensions for Dendronotus frondosus and Tergipes tergipes. The occurrence

of cold water opisthobranchs in New Jersey is explained in part by ocean water

temperatures which rarely exceed 25°C, by the numerous submerged artificial

structures, and by the predominant southwest flow of coastal water which may

transport eggs and young from breeding populations located to the north.

INTRODUCTION

In October, 1971, Ichthyological Associates, Inc.

began an ecological survey of the New Jersey

coast from Long Beach Island to Brigantine

Island. Since March, 1972, invertebrates were

systematically collected by a variey of methods

including substrate panels, clam dredge, ponar

grab, lobster pots, trawl, and SCUBA gear as

reported by Carlo, Hondo, and Miller (1975) and

McCullough (1975).

Recent reports by Franz (1968a, 1970) and

Loveland, Hendler, and Newkirk (1969) recorded

nudibranchs from Shark River, Delaware Bay,

Manasquan River, and Bamegat Bay. Loveland et

al. (1969) provided a checklist which summarized

distributional records of nudibranchs from New

Jersey. Franz (1968b), Marcus (1958), Miner

(1950) and Pruvot-Fol (1954) discussed their tax-

onomy and distribution.

24 THE NAUTILUS

January 27, 1977

Vol. 91(1)

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Vol. 91 (1)

January 27, 1977

THE NAUTILUS 25

RESULTS

More than 325 macroinvertebrate taxa were

collected from the study area during the period

between 1971 and 1975. Opisthobranchs were

taken between Little Sheepshead Creek and 15

kilometers southeast of Little Egg Inlet (Fig. 1).

Nine species of opisthobranchs (represented by

1,082 specimens) are discussed below (Table 1).

Specimens are deposited in the collections of

Absecon Laboratory of Ichthyological Associates,

Inc.

Some 95% of the specimens collected were

taken from artificial structures which included

lobster pots, substrate panels, buoy lines, ship

wrecks, and a weather tower. The rest were col-

lected from natural substrates such as shell rub-

ble encrusted with bryozoans and drifting

hydroids.

Pleurobranchaea tarda (Verrill 1880)

Thirteen specimens were collected by trawl

during August, October, and November, 1975, ap-

proximately 15 kilometers southeast of Little Egg

Inlet. Specimens were taken at depths of 18 to 20

m. Bottom water temperature at the time of col-

lection ranged from 14.2° to 17.0° C and salinity

was 32.0 ppt.

Abbott (1974) reported specimens off

Massachusetts and Delaware at depths from 51 to

567 m. Moore (1964) noted specimens from

floating Saiyassum in Vineyard Sound, Mass. and

in dredge samples taken at depths from 60 to

400 m. Our specimens are the first reported oc-

currence for New Jersey.

Acanthodoris pilosa (Miiller 1776)

Forty-four specimens were collected from 27

April 1972 through 3 September 1974. They were

taken in Little Sheepshead Creek, and from Lit-

tle Egg Inlet to a point 4.8 kilometers southeast

of Little Egg Inlet at depths of 2 to 11 m. Bottom

temperatures were 6.5° to 25.0° C and salinities

were 29.0 to 30.5 ppt. Egg masses were collected

in June when bottom temperature was 16.0° C

and salinity was 29.0 ppt.

Acanthodoris pilosa was found on shell rubble

which was covered with encrusting bryozoans

(particularly Alcyonidium sp.) and on cement

and masonite substrate panels colonized by Al-

Bexh Haven Inlel

€it^^g^;gi

FIG. 1. Area sampled in the vicinity of Little Egg Inlet,

New Jersey.

cyonidium, Obelia Jlabellata, and Tubularia

crocea; 7 were found on the gamma stage

of Cliona sp. The color of A pilosa varied from

gray to gray-pink to yellow and blended with the

habitat.

Abbott (1974) reported that it was found from

the Arctic to Ocean City, Maryland and in the

north Pacific, Japan, and Europe. A specimen

found in Delaware Bay, New Jersey, was

reported by Loveland et al. (1969). Acanthodoris

pilosa is established in natural and man-made

habitats near Little Egg Inlet but is uncommon.

Onchidoris bilamellata (Linnaeus 1767)

(Lamellidoris fusca in Abbott 1974, On-

chidoris fusca in Moore 1964)

Eight specimens were collected on a lobster pot

set from 23 July to 14 August 1973 near a wreck

located approximately 6.4 kilometers southeast of

Little Egg Inlet. They were relatively small (total

length ranged from 5.7 to 6.9 mm; mean 6.3 mm).

The depth ranged from 14 to 16 m; the bottom

temperature was 12.5° C, and salinity was 30.5

ppt.

Abbott (1974) reported its range in the Atlan-

tic from the Arctic to Massachusetts and Europe.

26 THE NAUTILUS

January 27, 1977

Vol. 91(1)

These are the first specimens reported from south

of Ijong Island, New York (Rozsa 1974).

Dendronotus frondosus (Ascanius 1774)

One specimen (1.8 mm total length) was col-

lected on a masonite panel which was set from 23

April to 1 July 1974. The panel was placed ap-

proximately 5 m below mean low water on a

weather tower located 3.7 kilometers southeast of

Little Egg Inlet. The bottom temperature was

20.0° C and the salinity was 29.5 ppt. Den-

dnmotus was associated with the hydroids Obelia

flahellata and Tubularia crocea.

Abbott (1974) reported its range in the

Atlantic is from the Arctic to New Jersey and

Europe. Loveland et al. (1969) found hundreds of

specimens associated with Tubularia on a floating

wharf in Shark River, N. J.

Tergipes was reported previously from the Arc-

tic to New Jersey and Europe and Brazil (Abbott

1974). Loveland et al. (1969) stated it was rare in

New Jersey; the two previous records were from

the Shark River.

Facelina bostoniensis (Couthouy 1838)

Three specimens were collected between 29

August 1972 and 8 October 1973 from lobster pots

and a buoy line located between 3.2 and 4.0

kilometers southeast of Little Egg Inlet in depths

of 9 to 10 m. Bottom temperatures were 19.0° to

22.0° C and salinities were 29.0 to 29.5 ppt.

Abbott (1974) gave its range as Nova Scotia to

Connecticut. Rozsa (1974) reported specimens

from Long Island, New York. These are the first

reported from New Jersey.

Doto coronata (Gmelin 1791)

Twenty-nine specimens were collected from

early May, 1973, to early December, 1974. Small

specimens and eggs were collected on floating

hydroids (Sertularidae) in May, 1973, in Little

Egg Inlet. A few were found associated with

Obelia flahellata on cement and masonite panels

placed 3.7 kilometers southeast of Little Egg In-

let. Bottom temperatures were 6.0° to 20.0° C and

salinities were 26.0 to 30.5 ppt.

Abbott (1974) reported it was distributed from

the Bay of Fundy to New Jersey and Europe.

Loveland et al. (1969) noted that it was originally

described from a collection taken in Great Egg

Harbor. N. J. by Verrill and Smith (1873). They

rediscovered it in Shark River in 1968. Our find-

ings indicate it is established but uncommon in

the coastal waters off New Jersey.

Tergipes tergripes (Forskal 1775), (Tergipes

despectus in Moore 1964, and in Franz 1968a)

Some 815 specimens were collected between 29

August 1972 and 6 December 1974 from a

weather tower, buoy lines, and cement and

masonite substrate panels located between 3.2

and 4.8 kilometers southeast of Little Egg Inlet.

Bottom temperatures were 6.0° to 20.0° C and

salinities were 29.0 to 31.0 ppt. Most specimens

were found where 0. flxiheUata was abundant and

T. crocea was common.

Cratena pilata (Gould 1870)

Some 164 specimens were collected between 29

July 1972 and 5 August 1974 on lobster pots,

buoy lines, and cement panels located 3.2 and 4.8

kilometers southeast of Little E^g Inlet at depths

from 8 to 15 m. Bottom temperatures were 13.0°

to 21.5° C and salinities were 30.0 ppt. Most

specimens were collected where T. crocea was

abundant.

It occurs from Nova Scotia to North Carolina

(Abbott 1974) and has been reported from

Barnegat and Delaware bays. New Jersey by

Franz (1968a). Our findings indicate it is abun-

dant in the coastal waters off Little Egg Inlet.

Aeolidia papillosa (Linne 1761)

Four specimens and several egg masses were

collected on 11 June 1973 by SCUBA divers on a

wreck approximately 8.8 kilometers southeast of

Little Egg Inlet at a depth of 15 m. Metridium

senile, the prey of A. papilhsa, was abundant on

the wreck. Bottom water temperature was 10.0° C

and salinity was 30.5 ppt.

Its range in the Atlantic is from the Arctic to

Maryland and Europe (Abbott 1974), and it has

been reported from the Shark and Manasquan

rivers, N. J. by Loveland et al. (1969). Our find-

ings indicate that breeding populations exist in

some coastal waters off New Jersey.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 27

DISCUSSION

Of the 9 opisthobranchs collected from the study

area, 6 are amphi-Atlantic (occur on both sides of

the Atlantic) and 3 are west-Atlantic endemic.

Franz (1970) concluded that 37% of the species

north of Cape Hatteras are west-Atlantic

endemics and our findings agree.

Of the amphi-Atlantic species, A. pilosa, D. cor-

onata. and T. tergipes are boreal and successful

reproduction cannot occur above 25° C (Franz

1970). In this study egg masses of D. coronata

and A. pilosa were collected at 15° C and 16° C,

respectively. 0. bilamellata, D. frondosus. and A.

papillosa are boreo-subarctic species and suc-

cessful reproduction cannot occur at

temperatures above 15-20° C. In this study egg

masses of ^. papillosa were found at 10° C.

Three factors contribute to successful establish-

ment of northern nudibranchs in New Jersey.

Temperature regimes near shore and in Little

Egg Inlet favor boreal species. Bottom

temperature never exceeded 25° C between

March, 1972, and December, 1974. At depths

greater than 15 m bottom temperature never ex-

ceeded 21° C, however, during the summer it was

between 20 and 21° C about 12% of the time. One

boreo-subarctic species was found reproducing

below the summer thermocline and this is a

suitable area for other boreo-subarctic species to

inhabit.

Loveland et al. (1969) stated that nudibranchs

and their eggs may be transported southward and

become rapidly established on man-made struc-

tures in New Jersey. Some 95% of those collected

in this study were from submerged man-made

substrates.

In summer, 1973, small specimens of 0.

bilamellata and D. frondosa were collected on

recently deployed substrates; this suggests they

were transported by water currents.

Charlesworth (1968) redrew maps from Bumpus

(1965) which show the general southwest drift in

the Middle Atlantic Bight. E. G. & G., En-

vironmental Consultants (1974) found that the

prevailing current in the study area in summer,

1973 was southwest with an average velocity of

12.1 km/day (surface) and 4.3 km/day (bottom).

D. frondosa could drift from existing populations

in Shark River to Little Egg Inlet in less than 2

weeks. The southwest drift may transport eggs

and young from northern populations and the

availability of suitable habitats and thermal

regimes in the study area facilitate their sur-

vival.

ACKNOWLEDGMENTS

This work is part of an ecological study for the

proposed offshore Atlantic Generating Station

sponsored by Public Service Electric and Gas

Company of New Jersey. Martha M. McCul-

lough, Jeffrey J. Hondo, and Charles B. Milstein

collected many of the specimens. Dr. David R.

Franz, Brooklyn College, confirmed the identifica-

tion of Acanthodoris pilosa and Lamellidoris

fiisca and Dr. Larry G. Harris, University of New

Hampshire, verified the identification of Facelina

bostoniensis.

I thank Dr. David R. Franz and Dr. Edward C.

Raney for reviewing the manuscript, Felicia A.

Swiecicki for the figure, and Linda N. Dill for

typing.

LITERATURE CITED

Abbott, R. T. 1974. American Seashells, the marine moUusca

of the Atlantic and Pacific coasts of North America. Second

ed.. Van Nostrand Reinhold Co., New York, N. Y. 663 p.

Charlesworth, L. J. 1968. Bay, inlet and nearshore marine

sedimentations: Beach Haven— Little Egg Inlet region, New

Jersey, Doctoral Thesis. Pts. 1, 2, and 3, University

Microfilms. Univ. Michigan, Ann Arbor.

E. G. & G., Environmental Consultants. 1974. Discussion of

general circulation in the New York Bight area. p. 6-1

through 8-1 in Summary of oceanographic observations in

New Jersey coastal waters near 39° 28' N latitude and 74°

15' W longitude during the period May 1973 through April

1974. Waltham, Mass.

Franz, D. R. 1968a. Occurrence and distribution of New

Jersey Opisthobranchia. Vie Nautilus 82(1): 7-12.

Franz, D. R. 1968b. Taxonomy of the eolid nudibranch,

Cratenapilata (Gould). Ches. Set. 9(4): 264-266.

Franz, D. R. 1970. Zoogeography of northwest Atlantic

opisthobranch molluscs. Mar. Biol. 7(2): 171-180.

Garlo, E. V., J. J. Hondo, and G. J. Miller. 1975. Benthic in-

vertebrates. 2: 26-64. In Ecological studies in the bays and

other waterways near Little Egg Inlet and in the ocean in

the vicinity of the proposed site for the Atlantic Generating

Station, New Jersey. Ichthyological Assoc, Inc., Ithaca, New

York.

Loveland. R. E., G. Hendler. G. Newkirk. 1969. New records of

nudibranchs from New Jersey. Veliger l\{i): 418-420.

McCullough, M. M. 1975. Epifauna, 2: 13-21. In Ecological

studies in the bays and other waterways near Little E^g

28 THE NAUTILUS

January 27, 1977

Vol. 91(1)

Inlet and in the ocean in the vicinity of the proposed site

for the Atlantic Generating Station, New Jersey.

Ichthyological Assoc.. Inc.. Ithaca. N. Y.

Marcus. E. 1958. On western Atlantic opisthobranchiate

gastropods. Amer. Mus. Nointates. No. 1906. 82 p.

Miner. R. W. 1950. Field Bonk of Seashore Life. G. P. Put-

nam's Sons. New York, N. Y. 888 p.

Moore, G. M. 1964. Shell-less Opisthobranchia, p. 1.5.3-164. In

R I. Smith (ed.) Keys to marine invertebrates of the Woods

Hole Region. Contr. 11, System.-Ecol. Program. Mar. Biol.

Lab.. Woods Hole, Mass.

Pruvot-Fol, A. 1954. MoUusques opisthobranches. Faune de

France 58: 421-436.

Rozsa, R. 1974. Preliminary checklist of the nudibranchs and

sacoglossa of Long Island. New York Shell Oub Notes 200:

7-8.

NOTES ON OCCURRENCE OF

EUPLEURA SULCIDENTATA DALL (GASTROPODA: MURICIDAE)

Wiliiam G. Lyons

Florida Department of Natural Resources

Marine Research Laboratory'

St. Petersburg, Florida 33701

ABSTRACT

Eupleura sulcidentata is reported from estuarine and coastal sites in southeast

Florida. Cuba, and tivo Bahamian Islands, demonstrating that the species is not a

west Florida endemic, and confirming Doll's original record fi-om Cuba.

In 1972, I collected six freshly dead shells of

Eupleura (Fig. 1) in beach drift along a sand spit

at White Sound on the lagoonal side of Elbow

Cay, Great Abaco, Bahamas. A literature search

(part of an ongoing treatment of the shallow

water Bahamian molluscan fauna) failed to

reveal any Bahamian records of Eupleura, so

specimens were sent to Dr. Emily Yokes, Tulane

University, who identified them as E. sulciden-

tata Dall, 1890. The specimens are deposited in

the Marine Research Laboratory invertebrate

reference collection (FSBC I) at St. Petersburg.

In his original description, Dall defined the

range of E. sulcidentata as "Gulf coast of Florida,

shores of Cuba." Smith (1937) also listed Cuba

within the range of the species, but Dall's Cuban

citation was evidently considered erroneous by

Johnson (1934), who listed only the Gulf coast of

Florida and Florida Keys, and by Abbott (1954,

1968), who further restricted it to west Florida.

Lyons et al. (1971) followed the latter in consider-

ing the species a west Florida endemic. Abbott

(1974) listed E. sulcidentata at Bimini, Bahamas,

revising its range to include both the west coast

of Florida and Bimini. A report of E. sulciden-

Contribution No. 290.

tata from Caibarien, on the north central Cuban

coast (Jaume and Sarasua, 1943) has evidently

been overlooked by subsequent authors. Dr. Ab-

bott suggested I contact Mr. J. C. Finlay, who

allowed me to examine nine Cuban specimens

(Figs. 2, 3) collected by him during 1957-1958 in

depths of 3-4 m on the Varadero side of the Bay

of Cardenas, about 200 km northwest of

Caibarien. Mr. Dan Steger provided an addi-

tional specimen from Varadero. Mr. Finlay also

provided three specimens (Fig. 4) collected off

Rickenbacker Causeway, Biscayne Bay, Miami,

Florida, during 1949-50. Most recently, I have ex-

amined 12 specimens (Fig. 5) collected by Mr.

Gene Everson while night diving in depths of 5-6

m immediately off Lake Worth Inlet, north of

West Palm Beach, Florida.

Eupleura sulcidentata occurs in estuaries along

the entire Florida west coast. Tabb and Manning

(1961) report specimens from Cape Sable and

northern Florida Bay, Cooley (manuscript) has

found the species at Pensacola Bay, and others

have been reported at many points intermediate

to these localities. The snails are common in

Tampa Bay (Fig. 6). where they usually live on

rocks over sand, on oyster reefe, or in grassbeds

in higher salinity portions of the Bay: they also

Vol. 91(1)

January 27, 1977

THE NAUTILUS 29

FIGS. 1-6. Eupleura sulcidentata DaH: Fig. 1 - Elbow Cay.

Gt. Ahaco (FSBC I 10131). Pigs. 2, 3 - Cardenas Bay. Cuba

(Finlay Coll.). Fig. 4 Biscatpte Bay (Finlay Coll.). Fig. 5 —

Lake Worth Inlet (Everson Coll.). Fig. 6 — Tampa Bay.

Florida (FSBC 1 2672). All figures X2.

occur near beaches where conditions remain

essentially estuarine. Habitat near the beach at

Elbow Cay included sand and turtle grass,

(Tlmlassia testudinum Konig) with occasional

rocks scattered throughout the area. Mr. Finlay

states that he commonly dredged E. sulcidentata

in 2-3 m on muddy sand in the Bay of Cardenas.

At Biscayne Bay, specimens were "not infre-

quently found clinging to the outside of smooth

objects such as bottles, cans, etc." Lake Worth In-

let specimens were found in shell rubble on sand,

apparently similar to areas where the species oc-

curs in nearshore waters of west Florida. The

Bahamian, Cuban, and Biscayne Bay sites are

relatively estuarine compared to other tropical

habitats, but faunal assemblages differ con-

siderably from those where E. sulcidentata occurs

along west Florida.

Lake Worth Inlet may approach the northern

range limit of E sulcidentata on the Florida east

coast. Extensive collecting by me at St. Lucie In-

let. 45 km to the north, has not produced this

species, although its northern congener, E.

candata (Say, 1822) has been found there.

Mr. Finlay 's specimens, as well as the report

by Jaume and Sarasua, confirm Ball's original

contention that E. sulcidentata is a component of

the Cuban fauna. Specimens from Lake Worth,

Biscayne Bay, and two Bahamian localities

demonstrate that the range of the species is con-

siderably greater than has been recently

recognized.

ACKNOWLEDGMENTS

I thank Messrs. John C. Finlay, Newark,

Delaware, the late Dan Steger, Tampa, Florida,

and Gene Everson, Ft. Lauderdale, Florida, for

graciously loaning specimens, and Mrs. Sally D.

Kaicher. St. Petersburg, for preparing the figures.

Dr. R. Tucker Abbott. Greenville. Delaware, pro-

vided additional information and comment. David

K. Camp and Mark J. Poff kindly read the

manuscript.

LITERATURE CITED

Abbott, R. T. 1954. American Seashells. D. Van Nostrand Co.,

Inc.. Princeton. 541 p.

Abbott, R. T. 1968. Seashells of North America. Golden Press,

New York. 280 p.

Abbott, R. T. 1974. American Seashells. 2nd ed. Van

Nostrand- Reinhold Co., New York. 663 p., 24 pis.

Cooley. N. R. (Manuscript). An inventory of the estuarine

fauna in the vicinity of Pensacola, Florida.

Dall. W. H. 1890. Contributions to the Tertiary fauna of

Florida, with especial reference to the Miocene silex-beds of

Tampa and the Pliocene beds of the Caloosahatchie River.

Part I. Pulmonate. opisthobranchiate and orthodont

gastropods. Trans. Wagner Free Inst. Sci. Phila.. 3: 200 p.

Jaume. M. L. and H. Sarasua. 1943. Notas sobre moluscos

marinos cubanos. Rev. Soc. Mai. "Carlos de la Torre" 1(2):

52-61, 1 pi.

Johnson, C. W. 1934 List of marine mollusca of the Atlantic

coast from Labrador to Texas. Proc. Boston Soc. Nat. Hist.,

40(1): 204 p.

Lyons, W. G., S. P. Cobb. D. K. Camp. J. A. Mountain, T.

Savage. L. Lyons, and E. A. Joyce, Jr. 1971. Preliminary in-

ventory of marine invertebrates collected near the electrical

generating plant. Crystal River, Florida, in 1969. Fla Dep.

Nat. Resour. Mar. Res. Lab.. Prof. Pap. Ser., 14: 45 p.

Smith, M. 1937. East coast marine shells. Edwards Brothers,

Inc., Ann Arbor. 308 p.

Tabb. D. C, and R. B. Manning. 1961. A checklist of the flora

and fauna of northern Florida Bay and adjacent brackish

waters of the Florida mainland collected during the period

July 1957 through September 1960. Bull. Mar Set. Gulf

Carib.. ll(4):552-649.

30 THE NAUTILUS

January 27, 1977

Vol. 91 (1)

NORTH AMERICAN LAND SNAILS IN ISRAEL

Henk K. Mienis

Department of Zoology

Hebrew University

Jerusalem , Israel

ABSTRACT

snails: Gastrocopta procera (Gould). Hawaiia

Three North American land

minuscula (Binney) and Zonitoides arboreus (Say) are reported fi-om Israel.

Recent investigations have revealed the

presence of several North American land snails

in Israel. Preliminary information is given in

this report in the hope that more attention will

be paid to other cases of introduced land

mollusks in the Middle East.

The material on which this work is based was

collected during field work carried out by the

author in support of the land snail project of the

"Fauna Palaestina Committee".

The following North American land mollusks

were collected in Israel:

Gastrocopta (Gastrocopta) procera (Gould, 1840)

In December 1972 a few empty shells of this

species were collected by Mr. S. Davis during a

field trip of students of the Hebrew University of

Jerusalem to the oasis of 'En Gedi, on the

western shore of the Dead Sea. About one week

later, very large numbers of this minute species

were found in litter under palm trees in the ir-

rigated palm gardens bordering the fields of kib-

butz 'En Gedi by Prof. G. Haas, Mr. S. Davis,

Miss T. Felsenburg and the author. More than

ten thousand specimens were extracted from less

than four kilograms of litter.

It was first identified as Gastrocopta procera

mcclungi (Hanna & Johnston, 1913) by Dr. L.

Forcart, but according to Mr. L. R. Hubricht (per.

comm.) all the specimens belong to the nominate

species Gastrocopta procera ((Jould). According to

the latter, it is almost impossible to discriminate

properly any subspecies within the species G. pi-o-

cera because of the many intermediate forms.

Hawaiia minuscula (Binney, 1840)

Like Gastrocopta procera this species was

found in large numbers in a litter sample taken

in the irrigated palm gardens of kibbutz 'En

Gedi. The identification of this species based on

shell characters was confirmed by Dr. L. Forcart.

Dr. A. Riedel later found the anatomy of a living

specimen to agree in every detail with that of

typical//, minuscula.

Zonitoides (Zonitellus) arboreus (Say, 1816)

Very large colonies of this species are present

in the open tree nursery of kibbutz Netzer

Sereni. Snails were first observed by the author

in January 1970, but this species must have

already been well established as thousands of liv-

ing snails were present. The snails are living on

and underneath containers (mainly tin cans) in

which saplings of sub-tropical fruit trees are

cultivated, in densities reaching 25 per container.

Eggs and juveniles are found during the entire

year, but are most numerous in the spring

(March-May). With the sale of young trees, snails

are transported to orchards and other nurseries.

The identification of Z. arboreus from kibbutz

Netzer Sereni has been confirmed by Dr. L. For-

cart and Dr. C. 0. van Regteren Altena.

Recently additional specimens of Z. arboreus

were collected by the author in an open

greenhouse of the Old Botanical Garden of the

Tel Aviv University near Abu Kabir, Tel Aviv (8

January 1975). A single specimen was found in a

hothouse of the Botanical Garden at the Givat

Ram campus of the Hebrew University of Jerusa-

lem (5 June 1975).

DISCUSSION

Zonitoides arboreus is a well known

greenhouse species which is widely distributed

Vol. 91(1)

January 27, 1977

THE NAUTILUS 31

over the whole world. (Pilsbry, 1946). It may have

been introduced with plants imported from North

America or from hothouses in Europe.

In the cases of Gastrocopta procera and

H(uraiia miymsmla. there is a clear indication

that they were imported directly from Southern

California. Both species were found in litter

under palm trees which were directly imported

from a nursery in the Coachello Valley in the

Salton Lake area. According to Pilsbry (1948) this

species was not known to live outside America.

From the large numbers in which these three

species have been collected, it is clear that all

have adapted very well under the artificial condi-

tions in Israel. Further passive dispersal of

Zonitoides arboreus is currently going on.

However, there is no positive data available

regarding the presence of this species in other

nurseries or orchards in Israel. Further dispersal

of Gastrocopta procera or Hawaiia minuscula

seems very unlikely, as both are living in the

isolated oasis of 'En Gedi in the Judean Desert,

and there only in irrigated palm gardens.

ACKNOWLEDGMENTS

Tlie author wishes to express his gratitude to

Dr. L. Forcart (Basel), Dr. C. C. van Regteren

Altena (Leiden), Dr. A. Riedel (Warszawa) and

Mr. L. R. Hubricht (Meridian) for their help in

the identification of the discussed material.

LITERATURE CITED

Pilsbr>', H. A. 1946. Land MoUusca of North America (North

of Me.xico). Acad. Nat. Sci. Philadelphia, Monog. 3. 2(1): 481.

Pilsbry. H. A. 1948. Land Mollusca of North America (North

of Me.xico). Acad. Nat. Sci. Philadelphia, Monog. .3, 2(2):

907-910.

EFFECT OF UPWARDLY-DIRECTED SHELL APERTURE ON

THE AESTIVATING LAND ^NAlh ACHATINA FULICA

S. K. Raut and K. C. Ghose

Department of Zoology

University of Calcutta

35 B.C. Road, Calcutta - 70(X)19 INDIA.

Water conservation is a serious problem in

land snails. Aestivation is the normal mechanism

to tide over the adverse conditions during dry

seasons in temperate and tropical countries.

Studies on the orientation of the shell aperture

in hibernating snails are very few. An upwardly

directed aperture during hibernation is common

in many land snails (Binney, 1851), in Mesodon

thifroidu,^ and Allogona profunda (Blinn, 1963),

and commonly upward in A. ptychophora

(Carney, 1967). A pronounced effect is expected in

specimens with long periods of aestivation, which

is supported from the studies on Achatinafulica.

METHODS AND MATERIALS

Three cages measuring 600 x 450 cm and 240

cm high were erected in a shady place in the

campus of Calcutta University at Ballygunge.

Sized wood, 7.5 x 5 cm thick, and of appropriate

length were used. The posts were fixed in the soil

with concrete bases. The sides and the ceiling

were covered with 1-cm expanded metal net. The

soil of the floor of the cages was loosened with

forks.

A limited amount of water was sprayed on the

soil on October 13 and 14, 1974. Then 200 healthy,

active, juvenile and adult Achatina collected from

their natural habitat were released in each of the

cages No. 1 and 2. The snails were acclimatized for

18 days and water was regularly sprayed during

the period to keep the soil sufficiently moist and

maintain a high percentage of humidity in the

cages. Favourite food was supplied in excess and

strict hygienic conditions were maintained. The

32 THE NAUTILUS

January 27. 1!)77

Vol. 91(1)

snails were vigorously active in the period of ac-

climatization.

To simulate the natural habitat of Achatina.

water-spraying was stopped on 2nd November,

but the food supply was continued.

OBSERVATIONS

Nov. 7, 1974: Most of the snails in both the

cages were partially buried in the soil or moving

to a corner indicating preparation for aestivation.

Some of the snails started moving up the frame

of the cage but they were brought down and

released on the soil.

Nov. 11, 1974: The rest of the snails became in-

active.

Nov. 13, 1974: Epiphragm was formed in all

specimens. In all cases the shell aperture was

directed downward.

Nov. 17, 1974: The aestivating snails in cage

No. 1 were turned upside down, i.e., the aperture

was directed upwards. The snails of the cage No.

2 were left undisturbed.

There was no rainfall until February, 1975,

when there occurred a total rainfall of 10.2 mm

in 5 days at certain intervals. Feb. 11, 1975: rain-

fall 3.9 mm. Feb. 12, 1975: rainfall 3.2 mm.

The humidity in February was maximum 95%,

minimum 35%. Temperature mean maximum 27°,

mean minimum 15.5°.

Feb. 12, 1975: 173 snails became active in cage

No. 1. The remaining were already dead. Four

specimens pushed out the epiphragm but soon

died. 114 snails became active in cage No. 2. Ten

snails were found dead under the epiphragm.

In a few days the snails in both the cages

underwent aestivation, all with the aperture

downward. The snails of cage No. 1 were again

turned upside down, so that the aperture faced

upward.

The month of March was dry. In the following

month the total rainfall was 5.1 mm in 4 days.

Apr. 25, 1975: Rainfall 3.2 mm; Apr. 26, 1975:

Rainfall 1.6 mm. The humidity in April was ma.x-

imum 91% and minimum 19%. Temperature

mean maximum 35.4°, mean minimum 24.8°.

Apr. 26, 1975: 107 snails became active in cage

No. 1. They were immediately transferred to cage

No. 3. 76 snails were active in cage No. 2. Apr.

27, 1975: 55 snails were dead under the

epiphragm. the foot and head of 11 snails were

pushed out of the shell and died in that state in

cage No. 1, and dead snails counted were 26 in

cage No. 2.

The snails in cages 3 and 2 aestivated within a

few days with the aperture downward. The snails

of cage No. 3 were again turned upside down.

A weak monsoon appeared in the first week of

June and with heavy showers in the middle of

the month all live snails in the cages became ac-

tive. The number dead was 44 in cage No. 3 and

.56 in cage No. 2.

DISCUSSION

The aestivation period in Stylommatophora dif-

fers with species and the country where they live.

For Achatina, the period is long between the

rains in Mauritius and Ceylon (Green, 1910: Hut-

son, 1920); during the dry spell in Singapore

(South, 1926); November to March in Hong Kong

(Herklots, 1948); November to June in India

(Ghose, 1959) and February to March in Hawaii

(Kondo, 1964). Helicella virgata aestivate for

about 5 months in Australia (Pomeroy, 1968),

while the period is only 2 months during summer

for Macrochlamys glaum in India (Hora, 1928).

Aiiophnnta is reported to aestivate in summer in

India (Hora and Rao, 1928) but the duration is

not on record.

Observations on the orientation of shell aper-

ture during hibernation in cold countries are on

record (Binney, 1851; Blinn. 1963; Carney, 1967).

The sole information on the influence of orienta-

tion of shell aperture during aestivation in

Allogona ptychophora is that of Carney (1966) in

Montana, U.S.A., where the snails are covered

with snow for sometime.

The main function of epiphragm appears to be

conservation of water. Both permeable and non-

permeable epiphragms have been reported in dif-

ferent Stylommatophora. The epiphragm is per-

forated in Helix aspersa (Allman, 1894-95), but

Smith (1899) recorded no perforation in the

epiphragm of H. aspersa and H. pomatia. Rees

(1964) considers the epiphragm of H. pomatia as

slightly permeable. Perforations on the

epiphragm have been reported from Thau mast us

sangoae (Smith, 1904), Gessula hastula and

Zootecus insularis (Hora, 1928) but these are

Vol. 91(1)

January 27, 1977

THE NAUTILUS 33

lacking in M glauca (Hora 1928). The epiphragm

of Achatina is not permeable and a narrow slit-

like opening in the epiphragm against the

pneumostome maintains communication between

the lung and the atmosphere. Smith (1899),

however, states that the slitlike structure in A.

immaailata is closed.

Loss of water, though in small amounts, is

associated with a reduced rate of respiration dur-

ing aestivation. It appears that to minimize the

loss further the shell aperture in A. fidica is

placed against the substratum, be it soil or some

other substance. The air locked in between the

epiphragm and the soil is considerably cooler

than the surrounding air. After two months

of aestivation and a week after a shower, con-

siderable amount of moisture in the expired air

condenses into small drops of water on the

epiphragm. In specimens with upturned apertures

such phenomenon was totally absent.

In Allogona ptychoph<yra the mortality rate is

normally 15.8%, but in specimens turned upside

down it is 36% (Carney, 1966). In Achatina. the

normal mortality percentage was 46 but in-

creased to 68.5 in the upside down group.

It appears that the method of aestivation with

the aperture of Achatina placed against the soil

is an adaptation towards conservation of water to

the highest possible degree.

LITERATURE CITED

Allman. G. J. 1894-95. Note on the Formation of the

Epiphragm of Helix futpersa. Pruc. Linn. Soc. Land. 25:

517-520.

Binney. A. 1851. The terrestrial air-lnvathing moltusks of the

United States and adjarent territories of North America.

Vol. 4. Little & Brown. Boston.

BHnn, W. 1963. Exrology of the land snails, Mcsodon thifroidtts

and Allogona profunda. EkoUiyyM: 498-505.

Carney, W. P. 1966. MortaUty and apertural orientation in

Allogona ptychophora during winter hibernation in Mon-

tana. The Naiddus 79(4): 1.34-36.

Ghose. K. C. 1959. Observations on the mating and oviposition

of two land pulmonates, Achatina fidica Bowdich and

Macrochlamys indica Godwin-Austein. J. Bombay Nat. Hist.

Soc. 56(2): 183-87.

Green, E. N. 1910. African snail {Achatina fidica). Trap.

Agriculturist 35(4): 311.

Herklots, G. A. C. 1948. Giant African snail Achatina fulica

Fer. Food and Flowers 1(1): 1-4.

Hora, S. L. 1928. Hibernation and aestivation in gastropod

molluscs: on the habits of a slug from Dalhousie (Western

Himalayas), with remarks on certain other species of

gastropod molluscs. Rec Ind. Mus. 30: 3.57-73.

Hora, S. L. and Rao. H. S. 1927. Hibernation and aestivation

in gastropod molluscs. Rec. Ind. Mus. 29(2): 49-62.

Hutson. J. C. 1920. The African snail (Achatina fulica). Trap.

Agricidturist 55: 217-25.

Kondo, Y. 1964. Growth rates in Achatina fidica. The

Nautilus78(iy.6-15.

Pomeroy, D. E. 1968. Dormancy in the land snails. Helicella

virgata (Pulmonata). Aust. J. Zool. 16: 857-69.

Rees. W. J. 1964. A review of breathing devices in land oper-

culate snails. Proc. Malac. Soc. Land. 36: .55-67.

Smith, E. A. 1899. Notes on the Epiphragm of Achatina im-

maculata Lam. Pirx-. Malac. Soc. Land. 3: 309-310.

Smith, E. A. 1904. Notes on the Epiphragms of Thaumastus

sangoae and T. tntaeniatus. Proc. Malac. Soc. Lond. 6: 3-4.

AMERICAN MALACOLOGICAL UNION

1977 ANNUAL AMU MEETING-The Naples

Shell Club will host the A.M.U. during its 42nd

Annual Meeting July 11-15,1977. There will be a

symposium on the Evolution of Mollusca, as well

as regular papers. Contact President George M.

Davis, Academy of Natural Sciences of Philadel-

phia, 19th and the Parkway, Philadelphia, Pa.

19103. Accommodations will be in the spacious

Naples Beach Club Hotel ($19 single; $22 double).

Contact Jerome M. Bijur, 135 Seventh Avenue

North, Naples, Fl. 33940. Detail notices are being

mailed to A.M.U. members.

34 THE NAUTILUS

January 27. 1977

Vol. 91 (1)

THE ASIATIC CLAM, CORBICULA MANILENSIS,

AS A FOOD OF THE NORTHERN RACCOON, PROCYON LOTOR

Ralph W. Taylor and Clement L. Counts. Ill

Department of Biological Sciences

Marshall University

Huntington. West Virginia 25701

In the growing mass of literature concerning

the Asiatic clam, Corhieula manilensis (Philippi),

few references have been made to their use as a

food item by other organisms. Lowery (1974)

noted in his mammal survey of Louisiana that

the northern raccoon, Procyon lot(yr (L.) utilizes

many molluscs in its diet. Many small streams in

West Virginia attest to this habit as sand bars in

these streams are often littered with many

broken, empty shells of bivalves surrounded by

footprints and scats of P. lotor. The present note

reports the use of C. manilerms as a component

in the diet of F. lotor in West Virginia.

Shells of C. manilensis were found in great

numbers along the southern bank of the Ohio

River, adjacent to a marsh, 2 miles north of

Lesage, Cabell County. West Virginia, in

September 1976. Many of the shells were broken

and found in scattered heaps. Surrounding the

shells were the footprints and scats of P. lotor.

Analysis of the scats revealed the presence of

shell fragments and one intact valve of a young

C. trianilensis, as well as assorted varieties of

seeds.

Voucher specimens have been placed at the

Delaware Museum of Natural History (DMNH

111490).

LITERATURE CITED

Lowery. G. H., .Jr. 1974. The Mammals of Louisiana and Its

Adjacent Waters. Louisiana State Univ. Press (Baton

Rouge). xxiii:.565pp.

THE ASIATIC CLAM, CORBICULA MANU^ENSIS

IN THE ILLINOIS RIVER

Carl M. Thompson and Richard E. Sparks

Illinois Natural History Survey

Havana. Illinois 62644

ABSTRACT

In 197i-75, specimens of the Asiatic Clam, Corbicula manilensis. were col-

lected at six locations on the Illinois River. Aye determinations of clams col-

lected suggest that Corbknla first appeared in the Illinois River in 1970-71.

Recent collections of the introduced Asiatic

clam, Corbicula manilensis, at six locations on

the Illinois River indicate a rapid range exten-

sion into this river system. On 23 August 1974,

we found 3 non-living shells of Corbicula on the

gravel shore of the Illinois River just downstream

from the ferry landing at Kampsville, Calhoun

County, Illinois (Illinois River mile 32.0).' The

.second find was made on 18 September 1974 at

' River miles above the confluence with the Mississippi River

as recorded in Charts of the Illinois Waterway. 1970, U. S.

Army Corps of Engineers.

Vol. 91(1)

January 27, 1977

THE NAUTILUS 35

Turkey Island Chute, Illinois River above

Kingston Mines, Fulton County, Illinois (River

mile 148.3). As before, the specimens were col-

lected on shore— this time in a concentration of

dead and weathered mollusk shells. In all, 12 in-

dividuals were collected at Turkey Island, 6 of

which contained tissue. Three specimens were

tightly closed and were found at water's edge,

suggesting recent desiccation. On 28 October 1974,

a third collection of 6 dead shells was made at

the lower end of Bath Chute, Illinois River below

Bath, Mason County, Illinois (River mile 106.7).

Once again, all specimens were found on shore in

a deposit of dead mussel shells. Clam collections

were made after a rapid July-August drop in

pool water levels of 18 feet at Bath and Kingston

Mines and 8 feet at Kampsville. Prior to this, the

nearest previous locality record was for the

Mississippi River at Granite City, Madison Coun-

ty, Illinois— first appearing there in 1965

(Thomerson and Myer, 1970). Three new records

were made in 1975: four specimens were found

on-shore at Upper Bath Chute (Illinois River mile

113.5) on 20 August, 1975. They ranged in shell

length from 10 to 14 mm, indicating they were

two-year-old clams. One live individual was col-

lected with an Eckman dredge from Sugar Creek

Island Chute (Illinois River mile 95.0) on 3

September, 1975. Shell length was 8 mm, also a

clam of the second-year-class. One other live

specimen was collected by Eckman dredging at

Sugar Island Chute (Illinois River mile 260.5) on

25 September, 1975. It was 12 mm long, a two-

year-old individual.

Other knovm Illinois records include the entire

length of the Ohio River bordering Illinois; at

two localities on the Wabash River— below New

Haven, Gallatin County and below Rising Sun,

White County (Parmalee, 1965); Granite City,

Madison County (Thomerson and Myer, 1970); the

Kaskaskia River near Baldwin, Randolph County,

25 miles above the confluence with the Mississip-

pi^ Crab Orchard Lake, Williamson County';

and at Lake Sangchris, a 2700-acre Com-

' Personal communication, Mr. Donald W. Dufford. Aquatic

Biologist. Illinois Natural Historj- Survey.

' Personal communication, Dr. R. Weldon Larimore, Aquatic

Biologist. Illinois Natural History Survey.

monwealth Edison power company impoundment

near Springfield, Sangamon County'. At this lat-

ter site, Corbicula has impeded water flow in the

plant cooling system.

National distribution records have been com-

piled by Sinclair (1971). A recent discovery near

Lansing, Iowa (Eckblad, 1975) establishes the

northernmost extent of Corbicula in the

Mississippi River System and the Midwest. It is

noteworthy that Corbicula at Lansing occurs in

heated effluent from a power plant. Also, the Il-

linois River in the vicinity of our collection sites

is warmer than the Mississippi at approximately

the same latitude. In 1973 during the period 1

November to 28 February, there were 103 days

when the water temperatures were measured on

the same days on both the Mississippi River at

Alton, Illinois and 75 miles north on the Illinois

River at LaGrange (River mile 80.2) (USGS,

1973). Even though the Illinois River location was

farther north than the Mississippi River station,

there were only 19 days when the minimum daily

temperature was at the freezing point on the Il-

linois and 36 days at the freezing point on the

Mississippi. The yearly mean temperature on the

Illinois at Havana (River mile 119.6) was 55° F.

while the Mississippi at Keokuk, Iowa, at approx-

imately the same latitude was 49° F. (Illinois

EPA, 1972). The thermal tolerance and preference

of Corbicula need to be determined before any

definitive statements can be made about the

probable northern limits of its range extension.

Identification of Corbicula manilensis was

made by descriptive characters given by Sinclair

and Isom (1963) and Burch (1972). Shell length

measurements were made on all specimens and

compared with published grovvth values (Sinclair

and Isom, 1961) for approximate age determina-

tion. All three valves found at the Kampsville

location were 12 mm in length indicating they

were clams of the second "year-class". Of the

specimens taken at Turkey Island seven ranged

from 12-18 mm and five ranged from 20-26 mm,

two- and three-year-old clams. Valve lengths for

the Bath Chute collection ranged from 17-29 mm,

also two- and three-year-old specimens, with the

largest individual, 29 mm, possibly representing

the fourth year-class. If the clams collected in the

36 THE NAUTILUS

January 27, 1977

Vol. 91(1)

Illinois River are considered tx) be representative,

Corhk'ula first occurred in the river in 1970-1971.

LITERATURE CITED

Burch. J. B.. 1972. Freshwater Sphaeriacean clams (MoUusca:

Pelec>'peda) of North America. Biota of Freshwater Eco-

systems Identification Manual No. 3. U. S. Elivironmental

Protection Agency. .'11 p.

hxkbiad, .James N.. 197.5. The Asian clam Corbiaila in the up-

per Mississippi River. The Nautiltis 89(1): 4.

Illinois Environmental Protection Agency, 1972. Water quali-

ty network. 1972 summary of data. Vol. 2. Illinois, Fox.

Sangamon, and Kankakee Basins. 243 p. Vol. 4. Mississippi

River (South. South Central, Central, North Central,

North), Big Muddy River. Kaskaskia River, and Rock River

Basin, 538 pp. Springfield. Illinois.

Ingram. William M., 19.59. Asiatic clams as potential pests in

California Water Supplies. Journal American Water WwA".s

Association 51(3): 3a3-370.

Ingram. William M.. L. Keup, and C. Henderson, 1964. Asiatic

Clams at Parker, Arizona. The Nautilus 11 (i): 121-124.

Parmalee. Paul W.. 1965. Asiatic clam (Gwbicula) in Illinois.

Transactions of the Illinois State Academy of Science 58(1):

39^5.

Sinclair. Ralph M. and Billy G. Isom. 1961. A preliminary

report on the introduced Asiatic clam Corbicula in Ten-

nessee. Tennessee Department of Public Health. Tennessee

Stream Pollution Control Board. 33 pp.

Sinclair. Ralph M. IWi!. Effects of an introduced clam (Cor-

bicula) on water quality in the Tennessee River Valley.

Proceedings of the Second Industrial Waste Conference,

Vanderbilt University. Tennessee Department of Public

Health Tennessee Stream Pollution Control Board. 14 pp.

Sinclair, Ralph M. and B.C. Isom, 1963. Further studies on the

introduced Asiatic Clam (Corbicula) in Tennessee. Ten-

nessee Department of Public Health. Tennessee Stream

Pollution Control Board. 75 pp.

Sinclair, Ralph M., 1971. Annotated bibliography on the exotic

bi-valve Corbicula in North America, 1900-1971. Sterkiana

43: 11-18.

Thomerson. Jamie E. and Donal G. Myer. 1970. Corbicula

manilensi.'i: range extension upstream in the Mississippi

River.5(erfria«o37:29.

United States Geological Survey. 1973. Water resources data

for Illinois. District Chief. Water Resources Division. U. S.

(jeological Survey. Champaign. Illinois. 300 pp.

BOOK

Pseudothecosomata, Gymnosomata attd

Heteropoda (Gastropoda). By S. van der Spoel.

1976. 484 pp., 246 figs. Bohn, Scheltema and

Holkema, Utrecht. Hardbacii, $60.00 U.S.

This book serves to bring together most of the

current information on the pelagic pteropods and

heteropods. A large mass of data, identification

keys and drawings, and distributional maps will

assist oceanographers working on plankton. The

bibliography is extensive. The book, however, is

difficult to use.

The several indices are tucked away in various

places in the text, and upon finding a reference

the reader is led, not to a page number, but to a

species number located on pages 16-22. Finally at

this point the figures, maps and page numbers

are revealed. The main treatment of a species

does not give any geographical information, nor a

reference to the proper maps at the end of the

book. One must search first among the systematic

table of contents to find a reference to the maps.

REVIEW

The nomenclatorial treatment of the

heteropods is very unsatisfactory, with a few

names being entirely ignored, such as Atlanta in-

flata Orbigny, 1836. The Atlanta names

legitimately proposed by Orbigny in 1836, Man-

dralisca in 1840 and J. E. Gray in 1850 are

erroneously considered to be nomina nuda

(tesselata [sic] Gould, 1852 and pulchella Verrill,

1884), presumably in an attempt to conserve cer-

tain better-known names. However, Gray's 1850

Cavolinia names are accepted. The genus

Mirrodonta Bonnevie, used by van der Spoel. is

three times a homonym, and should be replaced

by Prionoglossa Tesch, 1950.

Some additional illustrations of recently

described, shelled pteropods and newly recognized

forma are included with convenient keys. The

new subfamily Glebinae is proposed in the Cym-

buliidae.

R. Tucker Abbott

Delaware Museum of Nation History

Vol. 91(1)

January 27, 1977

THE NAUTILUS 37

Portrait o/All-j/n G. Smith taken in 1955

by Moulin Studios of San Francisco.

OBITUARY

ALLYN GOODWIN SMITH,

1893-1976

With the passing of Allyn G. Smith on August

18th, 1976, malacology lost one of its most ad-

mired and knowledgeable students of West

American mollusks. Bom June 4, 1893, in Hart-

ford, Connecticut, Allyn went to California in

1908, and later attended the University of

California at Berkeley, receiving a B. S. in Elec-

trical Engineering in 1916. After serving in the

U. S. Army in World War I, he returned to his

Alma Mater, to chair the Technical Department

in the Extension Division (1920-1924). In 1925, he

joined the Pacific Telephone and Telegraph Co.,

where he held the title of Supervisor of Personnel

at the time of his retirement in 19.55.

His special interests in pulmonate gastropods

and the chitons was initially generated by his

close friend, S. Stillman Berry, who fondly refers

to him as "one of my boys". He also knew the

Californian malacologist, Jo.siah Keep. During his

business career Allyn devoted much of his spare

time to field work, and he contributed numerous

malacological articles to journals. A major con-

tribution was a survey of "The Marine Mollusks

and Brachiopods of Monterey Bay, California and

Vicinity" (with Mackenzie Gordon, Jr.) published

in 1948.

Upon his retirement, he had hoped to devote

full time to research, but his administrative

talents were drafted by the California Academy

of Sciences, where he had served as a Research

Associate in Malacology since 1939. There he

started a new career in the capacity of Executive

Assistant to the director, 1955-1960, and as

Chairman and Associate Curator, he later

revitalized the Department of Invertebrate

Zoology, 1960-72. Despite these duties, he

prepared the section on "Amphineura" for the

Treatise on Invertebrate Paleontology, 1960, and

he continued publishing and field work, including

participation in the Galapagos International

Science Project in 1964. Author of 104 papers,

two of which appeared in 1976, he was active

until shortly before his death.

An energetic and compassionate man of many

interests and achievements, Allyn will be sorely

missed by his many friends and colleagues. He

leaves his wife, Katharine, and three children.

William K. Emerson, Curator of Mollusks

The American Museum of Natural History

New York, New York

Murex Shells of

the World

An Illustrated Guide to the Muricidae.

George E. Radtvin & Anthony D'Attilio. Photos

by Davtd K. Mt4lliner. Prepared for the ama-

teur collector as well as the professional

conchologist and malacologist, this exhaustively

detailed work is the first reliable taxonomic

treatment of the Muricidae since 1880. It offers

many innovations in classification, and pro-

vides descriptions, range data, and synonymy

for some 390 species (15 described here for the

first time). Illustrations include full-color

photos of 456 specimens, 61 black-and-white

drawings or photos, and 179 line drawings.

Introduction, Glossary, Bibliography, Index.

$35.00

Marine Algae of

California

Isabella A. Abbott & George J. Hollenberg.

Contributions by specialists. This first complete

systematic study of California seaweeds, an

extension of G. M. Smith's classic Marine Algae

oj the Monterey Peninsula, covers 80 percent

of the species known from Alaska to Panama.

Designed as a combined laboratory and field

reference, it illustrates each of the 701 taxa

treated by one or more line drawings, and

includes comprehensive information for all

species treated, an Introduction, a history of

West Coast algal study by G. F. Papenfuss,

maps, a Master Key to Genera, Glossary,

Bibliography, Index. $2.2.. 50

Stanford University Press

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MOLLUSK VOUCHER SPECIMENS

It is becoming increasingly important for

future research purposes that an identified sam-

pling of species mentioned in publications be

deposited in a permanent, accessible museum

specializing in mollusks. This is particularly

true of mollusks used in physiological, medical,

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The Delaware Museum of Natural History

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APRIL 25, 1977

THE

NAUTILUS

Vol. 91

No. 2

A quarterly

devoted to

malacology and

the interests of

conchologists

0

Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker.

Editor-in-Chief: R. Tucker Abbott

EDITORIAL COMMITTEE

CONSULTING EDITORS

Dr. Arthur H. Clarke, Jr.

Division of Mollusi<s

National Museum of Natural History

Washington, D. C. 20560

Dr. William J. Clench

Curator Emeritus

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. William K. Emerson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 1 0024

Mr. Morris K. Jacobson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 10024

Dr. Aurele La Rocque

Department of Geology

The Ohio State University

Columbus, Ohio 43210

Dr. James H. McLean

Los Angeles County Museum of Natural History

900 Exposition Boulevard

Los Angeles, California 90007

Dr. Arthur S. Merrill

Biological Laboratory

National Marine Fisheries Service

Oxford, Maryland 21654

Dr. Donald R. Moore

Division of Marine Geology

School of Marine and Atmospheric Science

10 Rickenbacker Causeway

Miami, Florida 33149

Dr. Joseph Rosewater

Division of MoUusks

U. S. National Museum

Washington, D.C. 20560

Dr. G. Alan Solem

Department of Invertebrates

Field Museum of Natural History

Chicago, Illinois 60605

Dr. David H. Stansbery

Museum of Zoology

The Ohio State University

Columbus, Ohio 43210

Dr. Ruth D. Turner

Department of Mollusks

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. Gilbert L. Voss

Division of Biology

School of Marine and Atmospheric Science

10 Rickenbacker Causeway

Miami, Florida 33149

Dr. Charles B. Wurtz

3220 Penn Street

Philadelphia, Pennsylvania 19129

EDITOR-IN-CHIEF

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Delaware Museum of Natural History

Box 3937, GreenviUe, Delaware 19807

Mrs. Horace B. Baker

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OFFICE OF PUBLICATION

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Subscription Price: $8.00 (see inside back cover)

THE

NAUTILUS

Volume 91, number 2 — April 25, 1977

CONTENTS

Twila Bratcher

Deshayes' Terebrid T>'pes in Ecole des Mines, Paris 39

John H. Rodgers, Jr., Donald S. Cherry, et. al.

The Invasion of Asiatic Clam, Corbicula manilensis, in the New River, Virginia 43

Robert C. Wall

Seasonal Movements of the Pond Snail, Lymnaea catascopium, in a Northern Lake 47

Eva Pip

Frequent Scalariformy in a Population of the Pond SnaW Zymnaea stagnalii 52

Robert F. McMahon

Shell Size- Frequency Distrihutions of Corbicula manilerisis Philippi from a Clam-fouled

Steam Condenser 54

M. G. Harasewych

Abnormal Hyperstrophy in Littorina lineolata (Gastropoda: Littorinidae) 60

Leroy H. Poorman and Forrest L. Poorman

Four Opisthobranchs Living on Marine Algae from West Mexico 62

Clement L. Counts, III

The Miocene Bivalve Cumingia medialis (Semelidae) from South Carolina 66

Tom M. Spight

Latitude, Habitat, and Hatching Type for Muricacean Gastropods 67

Walter 0. Cemohorsky

Comis viola, a New Name for C. inolacea Reeve 72

Tom M. Spight

Is Tfiaiii canalicidata (Gastropda: Muricidae) Evolving Nurse Eggs? 74

Branley A. Branson

The Chinese Apple Snail, Cipangopaludina chinensis,on

Orcas Island, Washington 76

Fred G. Thompson

The Polygyrid Genus McLeawm in Hispaniola 77

Publications received v Recent Deaths 80

PUBLICATIONS RECEIVED

Yonge. C. M. and T. E. Thompson. 1976. Liiing Marine

Molluscs. 228 pp., 162 text figs., 16 color pis. A well-written

textbook introduction, with the two opisthobranch chapters

by T. E. Thompson. Distributed in the U.S. by Amerirnn

Malai-nhKitsts. Publ., Box 42t)8, Greenville. De. 19807. $13.9.5.

Alonso, M. R. 1975. Fauna Malocologica Terrestre de la Depre-

sion de Granada (&pana). II. H Genero Helkella Ferussac,

1821. Cuademos de Ciencias Biologicas Granada, vol. 4, no.

1, pp. 11-28; I Pulmonados Desnudos, pp. 71-88.

Warmuth, John H. 1976. The Biogeography and Numerical

Taxonomy of the Oegopsid Squid Family Ommastrephidae

in the Pacific Ocean. Bull. Scripps Institute Oceanography,

vol.2;?,90pp. Paper.$:B..%.

Paraense, W. Lobato. 1976. Helisoma trivolris and Some of Its

Synonyms in the Neotropical Region (Mollusca: Planor-

bidae). Rev. BrasU. Biol. 36(1): 187-204.

Paraense, W. Lobato. 1975. Estado Atual da Sistematica dos

Planorbideos Brasileiros. Arg. Mus. Nac. RJ, vol. 55, pp.

105-128, 69 figs. Anatomy and shells well-illustrated.

Abbott, R. Tucker (Editor). April 1976. ne Best of ne

Nautilus. A Bicentennial Anthology of American Con-

chology. viii + 280 pp., 1 color pi., text figs. American

Malacologists, Publishers, Box 4208, Greenville, De. 19807.

Hardback, $13.95. Presentation copy with slip box, $38.00.

Hastings, Louise B. 1976. Index to the Taxonomic Names in

Edwin A. Joyce, Jr., 1972, A Partial Bibliography of

Oysters, with Annotations. Florida Dept. Natural

Resources, St. Petersburg. Pamplet, 40 pp. Available from

Delaware Museum of Natural History, Box 3937, Greenville,

De. 19087, by sending 3 13-cent postage stamps.

Quayle, D. B. 1975. Tropical Oyster Culture-A Selected

Bibliography. 40 pp. (267 entries). International Develop-

ment Research Center, Box 8500, Ottawa, Canada KIG 3H9.

$2.50.

Gasull, Luis and Juan Cuerda. 1974. Malacologia del Conten-

ido Gastrico de las Grandes E^trellas de Mar. Bol. Soc. Hist.

Nat. Baleares. vol. 19, pp. 1,5,5-173, 3 pis.

Franchini, Dario A. (EMitor). 1976. Simposio sui molluschi ter-

restri e dulcicoli dell' Italia Settentrionale. Mantova. 102

pp., 9 pis., text figs. 11 articles on such mollusks as

Cingulifera, Ancylus. Lartetia. Paladilhiopsis and

Dreissena.

Tchang. Si, et al. 1975. A Checklist of Prosobranchiate

Gastropods from the Xisha Islands, Guangdong Province,

China. Studia Marina Sinica. no. 10 pp. 105-132, 7 pis. (7

Nan-Hai Rd., Tsingtao, People's Republic of China).

Handel, Klaus. 1976. Morphologie der Gelege und Okologische

Beobachtungen an Buccinaceen (Gastropoda) aus der

Siidlichen Karibischen See. Bonn. Zool. Beitr., vol. 27, pp.

98-1X3. Also treats with fasciolariid and turbinellid egg cap-

sules.

Hubendick, B. and A. Warren. 1976. Framgalade Srackor fran

Svenska Vastkusten. Collection of 7 articles on the marine

prosobranchs of Sweden. Excellent illustrations in this

usefull handbook originally published 1969-1976. Box 11049,

Naturhist. Mus., Goteborg, Sweden 400.30. 25 kronors.

Shells and Shores of Texas

By Jean Andrews

This guide to the mollusks of the shallow marine

waters of Texas and the Gulf coast is arranged

according to the latest classification system, and

each entry Is accompanied by an illustration.

This book contains the clear, detailed depiction

of more minute species than any other one

source as well as one of the most extensive bibli-

ographies in the field.

512 pages, 24 color plates, 367 b&w photo-

graphs, 77 line illustrations

$19.95 through Dec. 31 , 1977; $24.95 thereafter

University of Texas Press ==

Box 7819 V^

Austin, Texas 7871 2

Vol. 91 (2) April 25, 1977 THE NAUTILUS 39

DESHAYES' TEREBRID TYPES IN ECOLE DES MINES, PARIS

Twila Bratcher

8121 Mulholland Terrace

Hollywood. Ca. 90046

It has been well over a hundred years since

Cierard Paul Deshayes published his descriptions

of 95 new terebrid taxa. The 33 species published

in 1857 in the Journal of Conchyliologie were

written with surprising detail for that period.

Those written by most of his contemporaries were

sketchy descriptions in Latin and could fit any

number of species. Deshayes followed his Latin

descriptions with excellent word pictures in

French of the species he was describing. Deshayes

must have loved each species he described. He

discussed them with such phrases as "beautiful

and precious," "this very beautiful and

remarkable species," "charming species." In one

description he said, "All the shell is smooth,

polished, shining as though it were made of

porcelain." The figures in his 1857 monograph are

exceptionally good in quality and detail.

The 62 taxa Deshayes described in the Pro-

ceedings of the Zoological Society of London,

1859, are less easy to evaluate. Although the

Latin descriptions are somewhat more detailed

than most of that period, they were not followed

by his fine French descriptions. They were

published without figures. Some of the taxa were

subsequently figured by Reeve. Some have never

been figured. In all his descriptions Deshayes

stated whether the material was from the Cum-

ing collection, now in the British Museum

(Natural History), or from his own collection,

now in the Ecole des Mines, Paris. In 1944 in his

"Deshayes Review of Terebra in the Journal of

Conchology," Tomlin stated, "Probably there is

more synonmy to be worked out with regard to

Deshayes" new species. It would-be a great ad-

vantage to get the types at the Ecole des Mines

overhauled."

When I visited the Ecole des Mines in the

spring of 1975, I located nine of the holotypes and

one probable holotype in the Deshayes collection.

Deshayes' detailed French descriptions, in addi-

tion to his original measurements, made this task

easier than it might have been. Because of his

careful attention to detail, specimens differing

substantially in measurement from those

published by Deshayes could not be accepted as

holotypes. An exception was Terebra eximia

Deshayes, 1859. Deshayes' measurements were 92

x 8 mm, which is evidently a misprint. The

specimen which appears to be the holotype

measures 46 x 8 mm. It is obvious that if a

specimen of this species should reach a length

should reach a length of 92 mm , the diameter

would be greater than 8 mm.

Some of the Deshayes taxa represented as be-

ing from his own collection could not be found at

all. The measurements of some differed substan-

tially from the original Deshayes measurements,

and are here considered paratypes.

TEREBRIDS FROM DESHAYES' COLLECTION

Terebra archimedis Deshayes, 1859, holotype, fig.

1 & lA. Not previously figured. Dimensions 31 x

5.8 mm. Original measurements 31 x 6 mm. In his

description Dehayes stated that this species was

representated in his collection only. Therefore I

believe the specimen in the Ecole des Mines is

the holotype rather than the specimen in the

British Museum (Natural History) cited as the

type by Cemohorsky (1969) which measures 32.7

mm in length. Type locality unknown. This is

conspecific with the Indo-Pacific species, T.

funicidata Hinds, 1844, and T. langfordi Pilsbry,

1921, as there are integrades between the forms.

Schepman illustrated T. archimedis in his Siboga

Expedition report, but the figure was of the

funicidata form rather than the archimedis form.

Terebra approximata Deshayes, 1859. No figure

was published. Type locality unknown. Reeve con-

sidered this taxa to be a junior synonym of T. un-

dulata Gray, 1834, a fairly common Indo-Pacific

species. No specimens of this taxa were found in

the Deshayes collection .

40 THE NAUTILUS

April 25.1977

Vol. 91

Terebra argeninllii Deshayes, 1859. No figure was

published. Type locality unknown. Reeve places

this taxa in synonymy with T. strigilata Lin-

naeus, 1758. No specimens of this taxa were

found.

Terebra chilensis Deshayes, 1859, holotype, fig. 2.

No figure previously published. Dimensions 40.2 .\

7.9 mm. Original measurements 42 x 8 mm. TVpe

locality Chile. Tliis is a synonym of T. gemmidata

Kiener, 1839, a rare species reported from Chile,

Patagonia, and Brazil.

Terebra chinensis Deshayes, 1859. No figure was

published. Type locality is China Seas. Reeve con-

sidered this conspecific with T. cingnlifera

Lamarck, 1822, a common Indo-Pacific species.

No specimens of this taxa were found.

Terebra columnam Deshayes, 1859. No figure

was published. Type locality unknown. Reeve con-

FUJ. 1. Terebra archimedis IJeshayes. 18.59, holotype.

FIG. 2. Terebra chilensis Deshayes, 18.59, holotype.

FIG. X Terebra crassula Deshayes. 18.59, paratype.

FIG. 4. Terebra crosxei Deshayes. 18,59. holotype.

FIG. 5. Terebra exiniia Deshayes. 18.59, holotype.

FIG. 6. Terebra mat heroniana Deshayes, 1859, holot>T)e on

left, paratype on right.

sidered this conspecific with T. cingulifera

Lamarck, 1822, as did Tryon. No specimens of

this taxa were found,

Terebra crassula Deshayes, 1859, paratype, fig. 3.

No figure was previously published. Dimensions

23. 6 X 5.2 mm. Original measurements 27 x 7

mm. Differences of measurements are sufficient

that this must be considered a paratype. Type

locality unknown. This is a synonym of Ha,'>tula

hmtata (Gmelin, 1891), a common western Atlan-

tic species.

Terebra crossei Deshayes, 1859, holotype, fig. 4.

No figure was published previously. Dimensions

24 X 5 mm. Original measurements 23 x 5 mm.

Type locality Indian Ocean, this is a synonym of

Hastula penicillata (Hinds, 1844) a common

Indo-Pacific species,

Terebra difficilis Deshayes 1859. Figured by

Reeve, Conch. Icon. vol. 12, pi. 18, fig. 86. Type

locality unknown. Reeve said of this species, "a

shell of solid growth, partaking somewhat of the

character of T. laiDoefomm. in which the fine

ribs are so crowded as almost to lap one on the

other. It comes even nearer to T. souleyti " Tryon

said it is conspecific with T. cancellafa Quoy &

Gaimard, 18.32. No specimens were found in the

Deshayes colletion.

Terebra dispar Deshayes, 1859. Figured by Reeve,

pi. 25, fig. 1.37. Type locality unknown. Reeve

said, "shining-white, semi-transparent. Very

closely resembles T. micans. " Tryon said it equals

both cinerea (Bom, 1778) and aciculina (La-

marck), two species which are quite distinct from

one another. No specimens found in the Deshayes

collection.

Terebra eximia Deshayes, 1859, probable

holotype, fig. 5. Figured by Reeve, pi. 21, fig. 106.

Dimensions 46.2 x 8 mm. Original measurements

92 X 8 mm, evidently a typographical error. Type

locality unknown. This is conspecific with T cor-

rugata Lamarck, 1822.

Terebra fimbriata Deshayes, 1857, holotype, fig.

10. Figured by Deshayes, pi. 5, fig. 1. Length 88.6

mm. Original measurements 88 x 19 mm. Type

locality unknovwi. There is a paratype in the

British Museum (Natural History). This taxa is a

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 41

junior synonym of T. crenulata Linnaeus, 1758.

Terebra glabra Deshayes, 1857. Figured by

Deshayes. Type of locality is China Seas. No

specimen was found in the Deshayes collection in

the Ecole des Mines. There is a specimen in the

British Museum (Natural History) marked Type,

T. glabra, which is obviously erroneous. Cemohor-

sky (1969) pointed out that "The specimen pres-

ent in the Cuming collection and measuring 43.3

mm in length (original measurement 70 mm) is

not the type; the holotype is probably in the

Ecole des Mines in Paris". The specimen in the

British Museum is a worn specimen of T. consors

Hinds, 1844, and Tomlin said it equals T. consors.

Deshayes said in shape, size, and coloration it

more nearly resembles T. cingulifera Lamarck,

1822. He also stated that the shell is all white or

of a white washed with pale beige. He made no

mention of the yellow blotches typical of T. con-

sors. Tomlin made his evaluation from the

specimen in the British Museum, and whether

that specimen- is the same species as Deshayes' T.

glabra probably will not be known unless the

Deshayes holotype is found.

Terebra histrio Deshayes, 1857. Figured by

Deshayes. Type locality unknown. Reeve and

Tomlin both mention that the type is cited from

the Deshayes collection but that there was one in

the Cuming collection which is merely a form of

T. cormgata Lamarck, 1822. Neither Deshayes'

description nor his figure is that of T. corTugata.

No specimen found in the Deshayes collection.

Terebra matheroniana Deshyes, 1859, holotype,

fig. 6 paratype, fig. 6 (right). Not previously

figured. Dimensions 17.4 x 3.3 mm. Original

measurements 18 x 3 mm. Type locality Tahiti.

TTiis is a species about which there has been

much confusion. E. A. Smith considered it a good

species and Tomlin agreed, citing Terebra lauta

Pease, 1869 as a synonym. I agree with that.

Reeve considered T. matheroniana a synonym of

T. aciculina Lamarck, 1822, to which it bears no

resemblance.

Terebra nbsoleta Deshayes, 1859, holotype, fig. 7.

Figured by Reeve, pi. 21, fig. 107. Dimensions 38.9

X 7 mm. Original measurements 40 x 7 mm. Type

locality unknown. Reeve mentioned that this

shell had indications of a brown band at the base

FIG. 7. Terebra obsoleta Deshayes, 1859, holotype.

FIG. 8. Terebra pundicidata Deshayes, 18.59, holotype.

FIG. 9. Terebra splendens Deshayes, 1859, holotype.

FIG. 10. Terebrafimbriata Deshayes, 1857. holotype.

FIG. 11. Terebra subanguluia Deshayes, 18.59, holotype.

FIG. 12. Terebra verreaun Deshayes, 1857, holotype.

which may have faded during the last hundred

years.

Terebra puncticuLata Deshayes, 1859, holotype,

fig. 8. Previously figured by Reeve, pi. 20, fig. 99.

Dimensions 24.6 x 6.2 mm. Original measure-

ments 25 X 6 mm. Type locality unknown.

Synonyms: T flava Hinds, 1844 (non Gray, 1834);

f. lutescens E. A. Smith, 1873.

Terebra souleyeti Deshayes, 1859. Figured by

Reeve, pi. 17, fig. 78. Type locality Gulf of Mexico.

No specimens fotmd.

Terebra splendens Deshayes, 1857, holotype, fig. 9.

Figured by Deshayes, pi. 5, fig. 11. Dimensions

73.8 X 12.6 mm. Original measurements 75 x 12

mm. Type locality is China seas. This is T.

dimidiata Linnaeus, 1758.

Terebra semidecussata "Deshayes". This is

evidently a manuscript name. It equals T

dislocata (Say, 1822).

42 THE NAUTILUS

April 25,1977

Vol. 91 (2)

Terebra subangidata Deshayes, 1859, holotype,

figs. 11. Previously figured by Reeve, pi. 18, fig.

87. Dimensions 33.6 x 6.8 mm. Original measure-

ments 34 X 7 mm. Typ)e locality unknown.

Terebra verremtxi Deshayes, 1857, holotype, figs.

12 & 12 A. Figured by Deshayes, pi. 5, fig. 3.

Dimensions 37.9 x 7.8 mm. Original measure-

ments :38 X 9 mm. Type locality unknown. This is

a synonym oiHastula strigilata (Linnaeus, 1758).

ACKNOWLEDGMENTS

I am indebted to the personnel of the Ecole des

Mines in Paris, particularly Mme. E. Fatton, for

the privilege of working with and photographing

the Tcirhridac in the Deshayes collection and for

help through correspondence since my return. I

also wish to thank Sally Kaicher for her advice

on shell photography and for her work in making

prints for publication from my negatives taken at

the Ecole des Mines; Dr. James McLean for his

comments and suggestions regarding this man-

uscript: and Dr. R. Tucker Abbott for the use of

his picture of the holotype of Terebra fimbriata

Deshayes.

LITERATURE CITED

Bom, Ignatius von. 1778. Indei Rerum Naturalium Muxpi

Casenrpl Vi iidnbonens-is. Part 1; Testacea pp. 1-458, 1 pit.

Cernohorsky, Walter Oliver. 1969. List of Type Specimens of

Terebridae in the British Museum (Natural History). The

Veliyer.um:2\0-2i.

Deshayes. Gerard Paul. 1857. Descriptions de nouvelles especes

du genre Terebra. Jmtr. de Conchyl. 6: 65-102, pits. 3-.5. 1859.

Deshayes, G. P. 18.59. A general review of the genus Terehni.

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and a description of new species. Pnic. Zool. Sue. London,

pp. 270-321.

Gmelin. Johann Frederich. 1791. Carol! a Linne Systema

naturae per regna tria naturae. Editio decima tertia. pp.

,'M98-3506.

Gray. John Edward. 1834. Enumeration of the species of the

genus Terebra, with characters of many hitherto un-

described. /Voc Zoal. Soc. Umdim for 1832, pp. 59-63.

Hinds. Richard Brinsley. 1844. Descriptions of new Shells, col-

lected during the voyage of the Sulphur, and in Mr. Cum-

ing's late visit to the Philippines. [On new species of

Terebra]. Proc. Zool. Soc. London for 1843, pp. 149-68.

Lamarck, J. B. P. A. de M. de. 1822. Histoire naturelle des

animaux vertebres, pp. 238-91.

Linnaeus. Carolus. 1758. .Systema naturae per regna tria

naturae. Eiiitio decima. reformata. pp. 741-42.

Pilsbry, Henry Augustus. 1921. Marine Mollusks of Hawaii

Vlli-XIII, Proc. Acad. Nat.. Set Philadelphia, pp. 300-09, pi.

12.

Reeve. Lovell Augustus. 1860. A monograph of the genus

Terebra. Conch. Icon. vol. 12, Terebra, pis. 1-27.

Reeve, Lovell A. 1860. A commentary of M. Deshayes's Revi-

sion of the genus Terebra. Proc. Zool. Soc. London, pp.

448-50.

Say, Thomas. 1822. An account of some of the marine shells of

the United States. Joitm. Acad. Nat. Sci. Philadelphia 2:

221-48.

Schepman, Matteus Martinus. 1912. The Prosobranchia of the

Siboga Expedition, part 5, Toxoglossa, Terebra, pp. 369-77,

pit. 25.

Smith, Exigar Albert. 1873. Remarks on a few species belong-

ing to the family Terebridae and descriptions of several

new forms in the collection of the British Museum. Annals

and Magazine of Natural History ll(4th): 262-71.

Tomlin, John Read le Brocton. 1944. Deshayes' review of

Terebra. Jam. Conch. 22: 104-8.

Tryon, George Washington. 1885. Man. of Conch., vol. 7,

Terebridae. pp. 3-64; 12 pis.

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Vol. 91 (2)

April 25, 1!»77

THE NAUTILUS 43

THE INVASION OF ASIATIC CLAM, CORBICULA MANILENSIS

IN THE NEW RIVER, VIRGINIA

John H. Rodgers, Jr., Donald S. Cherry, James R. Clark,

Kenneth L. Dickson and John Cairns, Jr.

Center for Environmental Studies

and Department of Biology

Virginia Polytechnic Institute and State University

Blacksburg, Virginia 24061

ABSTRACT

Corbicula manilensis appems to have successfully invaded the New River at

Glen Lyn. Giles County, Virginia in 1975. Mean population densities of 18 Cor-

bicula, m'^ were recovered doumstream from, a coal-fired generating plant while

29 individuals m'^ were found immediately upstream. This seems to be the pre-

sent limit of Corbicula immigration in the New River as no specimens were

taken from .^ampliiig si fes farthe r upstream. Relationships between shell deniensions

and shell weights, and viscera wet and dry weights were calculated from the

one size "year class" present. Correlation coefficients ranged from 0.9683 for

shell length and viscera wet weight to 0.6135 for shell dry weight and viscera

dry weight.

INTRODUCTION

The present paper is the first report of Cor-

bicula manilensis Philippi in the New River,

Virginia, and to our knowledge, only the second

report of Corbicula in this state (Diaz, 1974)'. Un-

til recently, extensive investigations of benthic

macroinvertebrates of the New River (con-

sidered by many to be the second oldest river in

the world) and its tributaries had not reported

any specimens of this clam. The range extension

of the Asiatic clam up this river is being careful-

ly monitored, since the New River is an impor-

tant source of water for various industries and

municipalities. The biology of this organism and

its relationships to other benthic and molluscan

fauna can be studied, since pre-invasion data are

available and this potential problem was revealed

in its infancy.

MATERIALS AND METHODS

Forty specimens of Corbicula manilensis were

' Tlie Delaware Museum of Natural History has numerous

adult specimens collected in 1974 by Mrs. Betty Piech near

Lanexa. Virginia, in the Chickahominy River which flows in-

to the James River.

randomly selected from quantitative collections

starting on 12 October 1976, from sites above and

below a coal-fired generating plant located on the

New River at Glen Lyn in Giles County, Virginia

(latitude-37°22'20", longitude-30°51'45", river

mile 95) (Fig. 1). The upriver station was

established 45 m above the intake pump station

through which water is drawn for condenser cool-

ing in the power plant. The plant generating

capacity is approximately 300 MW with a max-

imum of 340 MW. After passage through the

plant, the heated water may be raised to a max-

imum of 8 C above above ambient; however, dur-

ing these collections there was a 3 C difference

between the upriver and downriver stations (13 C

and 16 C respectively). The substrate was

characterized by gravel, sand and silt with sand

and silt comprising minor portions (after Hynes,

1970). The downriver station was located approx-

imately 50 m below the pipe through which the

heated water is discharged. The heated effluent

was usually chlorinated three times daily to con-

trol biofouling of the condenser pipes. At this sta-

tion, the substrate ranged from cobbles and peb-

bles to very fine sand with a predominance of the

former. During sampling, water depth at both

44 THE NAUTILUS

April 25.1977

Vol. 91 (1:

Stations ranged from 0.5 to 0.9 m with average

flows of 18-21 cm see"'. Alkalinity (as CaCOj), pH

and turbidity were 39 mg 1"', 7.80 and 35.0

Jackson Turbidity Units, respectively.

Samples were taken at each station using a

0.25 m^ quadrant and a net to a depth of 15 cm.

Clams were picked from each sample, counted,

placed in water on ice and transported to the

laboratory for further analyses. Travel time was

less than two hours and samples were processed

immediately. Dimensions and weights were deter-

mined as described by Joy and McCoy (1975).

0 C 20 so KILOMETERS

FIG. 1. Kanawha River basin and sampling sites on the

New River. X—Mud River, (hbell (.krunty. West Virginia;

second report of Corbicula from West Virginia, 10 October

1973 (Joy and McCoy. 197,5); h—Oielyan. Kanawha Qnmty.

We.it Virginin; first report of Corhicnld from West Virginia,

17 July 196:1 -population had been established .iince 1961 by

size "year class" data (Thomas and Mackenthun. 1961,1;

C—den Lyti. (riles County. Virginia; Corbicula collected IJ

October 1976 -pcrpulation had been estahlvihed since 197!> by

size "year class" data (River Mile 95); D—Ltirich. (riles

(hiinty, Virginia (River Mile 97); E— Narrows, (riles (hunty.

Virginia (River Mile i(>2); ¥— McCoy, Montgomery County.

Vi rgi n ia (Ri ver Mile 1 .11).

RESULTS AND DISCUSSION

The invasion rate of Corhieida in the Upper

Ohio and Kanawha River Drainage basin can be

estimated from available reports. Due to the

distinctive morphology of the adults and larvae,

the Asiatic clam is easily and likely to be

distinguished from indigenous bivalves. A collec-

tion of Corbicula reported from Chelyan. West

Virginia, (Fig. 1) indicated, by size "year classes,"

that a population had been established there

.since 1961 (Thomas and Mackenthun, 1964). A

subsequent collection in Cabell County, West

Virginia, was made in 1973 (Joy and McCoy,

1975). If the downriver area is the source of pro-

pagules for the population becoming established

at Glen Lyn, Virginia, the clams would have

traversed a distance of about 138 river miles in a

period of 15 years, or an average rate of about 9

miles year"'. Several physical barriers encoun-

tered alone the suspected path of invasion include

London Lock and Dam above Chelyan, Kanawha

County, West Virginia, and Kanawha Falls and

Bluestone Dam at Hinton, Summers County,

West Virginia. This dam forms Bluestone Lake, a

reservoir which is utilized for both flood control

and hydroelectric power. The relatively rapid

movement of the clam implies some augmenta-

tion of its natural dispersive mechanisms. It is

highly improbable that the nonparasitic plank-

tonic veliger larvae would be capable of moving

against the current at such a rate. Since no

parasitic stage is present in the life cycle, a fish

host would not be involved in dissemination

(Sinclair, 1964). More likely, their movement was

probably aided by fishermen as fishing pressure

is relatively intense in this river system. Addi-

tionally, transportation may have been provided

by waterfowl since Clench (1970) stated that Cor-

bicula may be able to pass through the intestinal

tracts of ducks in viable condition. Live

specimens are being sold and shipped to fish hob-

byists around the country (Abbott, U)75). Subse-

quent intensive sampling of the New River

upstream from Glen Lyn at Lurich, Narrows and

McCoy, Virginia, did not yield any specimens

(Fig. 1). These results indicated that the clam had

not yet been able to invade these areas.

Based on approximations of age from shell

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 45

TABLE 1. Means l± S E) and ranges of parameters meaKured far Corh\cu\a sampled friiin upriver and dmenriver stations.

lengths (Joy and McCoy, 1975), it was apparent

that the Corbkida collected at Glen Lyn were in

their first year (Table 1). Most of these specimens

were probably sexually mature (Gardner et al.,

1976) and should have been in the area since

1975. Mean density at the downriver station of 18

clams m"^ was significantly less (t-test, 0.05 level)

than the mean density of 29 m'^ at the upstream

station. This difference may be attributed to the

influence of the power plant discharge or a

substrate-associated distribution phenomenon.

This subject as well as seasonal density dynamics

will be further examined in future research.

Least squares regressions (of the form y = a

+ bx) and Pearson product-moment correlation

coefficients (r) were calculated for ten relation-

ships between shell dimensions and weights, and

viscera mass weights (Table 2). All correlations

TABLE 2. Regression analysis equations (y = a + bx) and

correlation coefficients for various relationships between shell

dimensions and weights, and wet and dry viscera weights of

Corbicula.'

Equations

- Vaki.

'W = width of shell (mm)

L = length of shell (mm)

VWW = wet weight of visceral mass (mg)

VDW = dry weight of visceral mass (mg)

S = dry weightof shell (mg).

' Significance level, P = 0.0001.

were highly significant (P<0.01) although the cor-

relation coefficients were slightly less than those

of Joy and McCoy (1975). This can be explained

by the variability associated within the one size

class in this study compared with a range of size

classes (from about one to more than four years)

collected by Joy and McCoy (1975). It is in-

teresting to note that the width of their

specimens averaged about 66% of the clams'

lengths which agreed closely with the average of

70% in this study. Sinclair and Ingram (1961)

reported somewhat different morphology in

specimens from the Tennessee River (shell width

about 89% of length based on their published

photographs). Only the correlation between shell

length and viscera wet weight was greater in this

study (r = 0.9683) than in the investigation of

Joy and McCoy (1975) (r = 0.9407). Results of this

study agreed with the observation of Joy and Mc-

Coy (1975) that viscera wet, rather than dry,

weight correlation coefficients are greater and in-

dicate that noncombustible mineral uptake

varied more per individual than water content.

It is anticipated that the impact of Corbicula

on this river system will be exhibited primarily

in two different areas: 1) decline in populations

of other bivalves as seen during the invasion of

the Altamaha River in Georgia (Gardner et al.,

1976); and 2) increase in problems associated

with industrial and municipal water use (Sin-

clair, 1964, 1971). The survival of indigenous

species of Margaritifera, Tristigonia, Elliptio,

Sphaerium and Piddium in the New River ap-

pears to be seriously threatened.

ACKNOWLEDGMENTS

Appreciation is expressed to James H. Ken-

nedy, Biology Department, Virginia Polytechnic

Institute and State University, for confirming

46 THE NAUTILUS

April 25,1977

Vol. 91 (2)

identification of Corbicula and to employees of

Applachian Power Company's Glen Lyn Plant for

cooperation during the river collections.

LITERATURE CITED

Abbott. R. Tucker 197.5. Beware the Asiatic Freshwater Oam.

Tropical Fish Hnhhi/ist. 23: 1.5 (Feb.).

Clench. W. J. 1970. Corbicula manilensis (Philippi) in lower

Florida. The Nautilus 84(1): 36.

Diaz, R. .J. 1974. Asiatic clam, Corbicula manilensis (Philippi),

in the tidal .James River, Virginia. Chesapeake Sci. 15(2):

118-120.

Gardner, J. A., Jr., W. R. Wo<xiall, Jr., A, A. Staats, Jr. and J.

F. Napoli. 1976. The invasion of the Asiatic clam {Corbicula

manilensis Philippi) in the Altamaha River. Georgia. The

NautUus90{:i]: 117-12.5.

H>Ties, H. B. N. 1970. The Ecology of Running Waters. Univ.

of Toronto Press, Toronto. 555 pp.

Joy, J. E. and L. E. McCoy. 1975. Comparisons of shell dimen-

sions and viscera mass weights in Corbicula manilensis

(Philippi, 1*4«). The Nautilus 89(2): .51-.54.

Sinclair, R. M. 1964. Clam pests in Tennessee water supplies.

Jour. Amer. Water Works Assoc. 56: 592-599.

Sinclair, R M. 1971. Annotated bibliography on the exotic

bivalve Corbicula in North America, 1900-1971. Sterkiana

43:11-18.

Sinclair, R. M. and W. M. Ingram. 1%1. A new record for the

Asiatic clam in the United States, the Tennessee River. The

Nouh/iAs 74(3): 114-118.

Thomas, N. A. and K. M. Mackenthun. 1964. Asiatic clam in-

festation at Charleston, West Virginia. The Nantilux 78(1):

28-31.

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Vol. 91 (2) April 25. 1977 THE NAUTILUS 47

SEASONAL MOVEMENTS OF THE POND SNAIL.

LYMNAEA CATASCOPIUM IN A NORTHERN LAKE

Robert C. Wall

Division of Mathematics and Science

Lake-Sumter Community College

Leesburg, Florida 32748

ABSTRACT

These data from a 3-year study in Lake Ann, located north of Interlochen in

the northern Lower Peninsula of Michigan, indicate that the freshwater

pulmonale snail Lymnaea catascopium (formerly L. emarginata) does not

migrate into deep water with the approach of winter. Tfii^'i behavior pattern dif-

fers from that reported by Cheatum (1931t). The observations indicate that while

these snails do move within the popdation, their movements are random in

nature with no tendency to migrate into deeper off-shoal water in the fall. If

anything, the data collected actually show their movements were more toward

shore than away from it. The difference in migration reported could be due to

differerwes in the periods the observations were made. The studies by Cheatum

and Brackett were primarily in late summer, early fall, and late spring; thw

study covered all seasons in the course of 3 years, i.e.. late fall winter, and

early spring as ivell as the periods designated by Cheatum and Brackett. It was

established that while there were snail movements within the population as ex-

hibited by L. catascopium during the winter, those movements were random in

nature, and not migratory.

INTRODUCTION migration patterns of pulmonate snails in

Some pulmonate snails that inhabit temperate Douglas Lake. The following information was

lakes are known to migrate from shallow into obtamed durmg a 3-year study of Lymnaea

deeper water with the onset of cold weather in catascopium Say, 1817 (of which L emarginata

the fall; they return from deeper water onto Say, 1821, is a synonym, fide H. J. Walter,

shoals of the lakes in the spring. This pattern of 1969). The observations were made in Lake

migration has been assumed to be normal for ^nn, north of Interlochen in the northern I^wer

most of the larger pond and lake snails and Peninula of Michigan to determine whether this

malacologists assumed it was the usual pattern. ^nail shows any appreciable seasonal migratory

However, data obtained in a 3-year study in- movement.

dicates that the seasonal migration of at least Snails involved in the transmission of a skin

one species does not follow that pattern. disease in the Great Lakes region known as

Earlier work by Cheatum (1934) in Douglas schistosome dermatitis or swimmers' itch, are

Lake, Cheboygan County, Michigan indicated often in colonies or "beds" covering fairly exten-

there was seasonal movement of several aquatic sive areas in shallow water (less than 1.5 meters

gastropod species which he interpreted as in depth). Assuming a seasonal migration takes

"migration." Later, Brackett (1940) concluded place and the host snails migrate into deeper

that snails he observed did not have an annual water in the fall to assemble in smaller and

migratory cycle, but remained "year round in restricted profundal areas, control could then be

the vicinity of where they hatched." Un- easier, more efficient, and less costly. Under

fortunately, neither Cheatum nor Brackett ob- those circumstances less damage would occur to

tained winter data from Michigan's northern the biota in the lake than with the treatment

lakes. More recently, Clampitt (1972a,b) studied methods currently utilized. The best method of

48 THE NAUTILUS

April 25.1977

Vol. 91 (2)

control would involve applying chemical treat-

ment just after fall migration or early in spring

before the snails come back into shallower

water. Such considerations tend to stress the im-

portance of resolving the controversial question

as to whether host snails migrate or not in the

seasonal way described.

LAKE ANN STUDY SITE

This investigation was started August 1966

and terminated in June 1969 at the beginning of

the annual breeding season of Lynniaea

catascopium. During the summer of 1966 an ex-

tensive survey was undertaken in the Lower

Peninsula of Michigan to determine which lakes

were reported to have outbreaks of schistosome

dermatitis. Among them, Lake Ann, Benzie

County, had on its northern shoal a thriving

colony of Lymnaea (Stagnicola) catascopium.

the snail reported by Cort (1950) as a principal

vector of schistosome dermatitis. Although

"swimmers' itch" was reported in that lake and

copper sulphate treatment had been applied,

several years had intervened prior to this study,

so that the snail population had again become

well established.

Lake Ann is 13 miles southwest of Traverse

City, Michigan in Benzie County, T. 27N, R.

13W, Sections 22, 23, 26 and 27, and covers 515

acres; its maximum depth is 23 meters. The bot-

tom of the lake, at about 12 meters in depth, is

covered with a pulpy peat. In the more shallow

areas marl covers the bottom; a narrow band of

sandy shore occurs only along the north and

east with a long stretch of beach to the west.

The snails studied were on a sandy shoal along

the north side of the lake where they were most

abundant in the area extending from shore to 8

meters out into water up to 0.5 meters deep.

Snail density near shore averaged 240 per square

meter; it declined sharply with increased depth

of water, so that beyond 39 meters from shore

and at depths greater than 1.5 meters, snails

were scarce. Using a motor boat and wire-mesh

dredge, quadrat sampling was made from 1.5

meters of depth to 12 meters of depth; however,

no live specimens of L. catascopium were

recovered. The snail bed clearly was confined to

that shallow shoal area.

PROCEDURE AND OBSERVATIONS

The First Year: Trips were made from Ann

Arbor to the study area at Lake Ann on a

schedule as follows: August 15, September 25,

October 6 and 25, and November 17, 1966;

January 24, March 28, April 27, June 1, July 12,

and September 28, 1967-a total of 11 trips dur-

ing the first year of the study. On October 25,

1966, 1280 snails were marked with red nail

polish covered by lacquer. Specimens varied in

size from 11 to 22 mm in length (measured from

apex to base of aperture). As soon as the mark-

ings were dry, the snails were returned to the

area from which they were collected and scat-

tered randomly over the snail bed.

During the periodic visits to that site in the

fall, winter and spring of 1966 to 1967, it was

clearly evident that, contrary to information ob-

tained from Cheatum's earlier studies, these

snails did not exhibit a seasonal migration.

While they tended to "group" in two's or three's,

there was no mass movement of that population

into deeper water as compared to their position

on the shoal area then inhabited during August.

Observations made of their position on the

shoals and under the ice during January and

March 1967 also indicated that they remained in

the same area inhabited during that fall and

winter. In January and March a thick ice cover

was found on the lake except for a strip about 3

meters wide along the shore. Snails were seen

from the water's edge outward. Since the opa-

queness of the ice made observations through it

impossible, a hole was chopped and live snails

were seen on the substrate. Many of the marked

snails were observed among others in the open

water near shore; however, none of the marked

individuals were seen through the hole in the

ice. Although the red nail-polish on the marked

snails had faded badly, it still was visible. In

April, soon after the ice had melted, a quadrat

sampling was made using a wire dredge. Sam-

ples were taken at approximately 25 meter inter-

vals from near shore (in a southwesterly direc-

tion) out into water 12 meters deep. The total

distance of the quadrat was about 350 meters. No

snails other than a few small Campeloma

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 49

decisum were recovered in water deeper than 2

meters.

The number of marked individuals seen dur-

ing the June visit was estimated to be about 10

per cent of the sample marked. By this time the

nail polish had almost completely faded making

it extremely difficult to distinguish marked from

unmarked individuals. Even with the aid of a

glassbottom bucket, wave action made observa-

tion difficult in shallow water.

Very few (about 5 per cent) of the marked,

dead (shells) were recovered during the April and

June visits. Possible explanations for the small

percentage of "sightings" of marked individuals,

both living and dead, are: fading of the nail

polish made them difficult to spot; many in-

dividuals were almost completely buried in the

substrate; disappearance as caused by various

snail "predators;" marked individuals may have

been selected because of their conspicuousness;

marking materials may unknowingly have been

toxic to the animals; wave action which tended to

be quite severe on this shoal made seeing them

difficult. For whatever reason, the true

significance of this study was finding marked

animals only in the immediate vicinity of the

shoal where they had been placed rather than

where these snails were subsequently recovered.

Although during the 3-year period numerous

checks made in all directions from the area in

which marked individuals were placed. No

marked individuals, living or dead, were ever

found more than 2 meters from the shoal on

which snails had been placed.

The Second Year: Based on information ob-

tained during the first year, the frequency of

visits to the study area during the next 2 years

was reduced from 11 to 5 trips. However,

throughout the 3 years, observations were made

at the study site every month of the year except

December.

In October of the second year, 3 study

quadrats, each covering one quarter square

meter, were laid out as follows: Plot I, 14 meters

from shore in water .12 meters deep; Plot II, 27

meters out in water .51 meters deep; and Plot III,

39 meters from shore in water .69 meters deep.

These measurements were made from the shore

to each study plot, compass readings were made,

and onshore landmarks were recorded so that

several criteria were available to help relocate

the study plots on subsequent visits. The purpose

of these quadrats was to determine whether the

snails moved around within the larger snail bed.

The number of snails in each of the 3 plots was

counted and a sample of 15 snails per plot was

marked with red India ink and then returned to

their respective plots. Because of its longer

lasting quality, India ink was used instead of the

nail polish to mark those shells. There were 115

snails in Plot I; 41 in Plot II; and 35 in Plot III.

During subsequent visits the number of marked

and unmarked snails per plot was determined.

Visits to the study area were made on November

16, 1967; February 14 and May 15, 1968.

During the November visit the weather was

cold (air temperature 1.5''C, water temperatue

3.0°C) and windy. Many snails were tossed about

by wave action, others were observed buried to

various degrees of submergence in the substrate:

only 2 snails (unmarked) were seen in Plot I;

some may have been buried in the substrate. In

order not to disturb the study plot, it seemed ad-

visable not to dig into the substrate. Two marked

snails (13.2% of the sample placed in this area)

were sighted .5 meter from Plot I toward shore;

12 snails, including 2 marked individuals, were

seen in Plot II. Two additional marked snails were

found .3 meter inshore from Plot II. Thus, 26.4%

of the marked snails placed in this area were

seen. Fourteen snails were observed in Plot III,

none of which had been marked. Two marked

specimens were observed .3 meter inshore from

this plot. The area around each study plot, out to

a distance of 3 meters, was checked. No other

marked snails were seen. Although more speci-

mens were observed outside the study plots than

inside, they were less numberous everywhere

than in October. Many were now buried in the

substance.

During the following February a heavy ice

cover was on the lake ranging from 5 cm at the

shoreline to 45 cm at 27 meters from shore.

Although snails were seen at the shore and

through a hole chopped in the ice 27 meters from

shore, no marked snails were seen during this

50 THE NAUTILUS

April 25,1977

Vol. 91 (2)

visit. On May 15, the air temperature at Lake

Ann was 25.5°C and the water temperature was

16.0°C. Only one marked snail (6.6% of the

marked sample) was found in the area around

Plot I; it was 3 meters west of the plot. Three

marked animals (19.8% of the sample placed in

Plot II) were found inshore within 5 meters of

Plot II. None of the marked snails placed in Plot

III was found. Since all snails had been marked

with the same color of India ink, there was no

way to determine the plot from which they had

come. As expected in terms of the annual cycle,

population density again dropped drastically

from an average of 240 per square meter in Oc-

tober to an average of 30 per square meter in

mid-May. Population densities were greatest near

shore and declined rapidly toward deeper water

during all of the months in which observations

were made.

The results of the first year were again

substantiated since these snails did not migrate

into deeper water off the shoal, but remained

where they had been during summer and fall.

While there were movements of snails within the

population, it was impossible to determine

whether these movements gave evidence of a pat-

tern or were of a random nature.

The Third Year: Based upon the studies of the

first and second years, some innovations were

made this third and final year of investigation.

The three established quadrat plots were left in-

tact. Three samples, each with 200 individuals,

were marked but a different color of a paste In-

dia ink was used for each of the samples. Sample

one was yellow; sample two, red; and sample

three, blue. Specimens in sample one (yellow)

were then scattered in a 20 meter radius arc in

the study Plot I, some 14 meters from shore; the

sample two (red) snails were scattered in a 30

meter arc in Plot II at a distance of 27 meters

from shore; and the sample three (blue) snails

were likewise scattered in a 40 meter arc in Plot

III at 39 meters from shore. Care was taken to be

sure that these samples passed through each of

the 3 earlier study quadrats established during

the second year of the study. This arrangement

served to determine the extent to which the

snails ranged within the total population area.

The 3 snail samples were marked October 25,

19()8. Subsequently, 3 trips to examine the extent

of movement were made to the study area on

March 7, April 19 and June 16, 1969. An unfore-

seen accident made visits to the study area im-

possible during December or January as original-

ly planned.

By March 7 the air temperature was 4.0°C and

the water was 4.5°C. TTie lake was still covered

with a thick cover of ice except for a strip about

6 meters wide along the shore. Although all 3

study plots were ice covered, 4 yellow-marked

snails (2% of the total sample) and numerous un-

marked animals were seen in that open water.

The population density again had decreased con-

siderably as in the previous 2 years.

On April 19 it was ascertained that the ice on

that lake disappeared about April 15. The air

temperature on the 19th was 15.0°C, the water

was 5.0°C. Using a glass-bottom bucket and the

distance guide used for setting the 3 plots, a

careful survey was made in each area. Dredgings

were made with sweeps on the arcs established

for Plots I, II and III; additional sweeps were

made at 1 meter intervals between plots. Only

those snails marked with the color designated

within the plot distances (Plot I, yellow; Plot II,

red; Plot III, blue) were found within the plot

arcs. With but one exeption, all marked snails

observed at other than the plot arc distance from

shore were inshore from their respective plot

arcs. The exception was 2 red-marked individuals

found 3 meters out from the Plot II distance arc.

A total of 77 per cent of the marked snails

recovered were at plot arc distance from shore, 19

per cent were inshore from their plot arc

distance, and only 4 per cent of the marked snails

recovered were out beyond their plot distance

arc. Of the 2(K) yellow marked specimens 23 or

11.5% were seen on this visit; 13 or 6.5% of the

2(H1 red: and 17 or 8.5% of the blue were found.

During the final visit on June 16, the air

temperatue was 22.0"C; the water was 21.0°C. A

general survey of the whole snail bed revealed

that most adult snails had already died. Many

shells had eggs attached to them; however, no

young snails were found. As during the April 19

visit, a careful survey was made of the studv

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 51

area. In sweeps made at 1 meter intervals from

shore outward to 2 meters beyond the Plot III

distance from shore, very few live sails were seen

and but a few shells. The following marked shells

and 1 live, marked snail were found: 1 yellow

shell at Plot I arc distance from shore; 1 red shell

1 meter inshore from the Plot II arc distance: 1

blue shell 3 meters inshore from Plot III arc; 1

blue shell 2 meters inshore from Plot III arc

distance; 1 live blue marked near Plot III; and 2

blue marked shells (one with eggs attached) 2

meters out from Plot III arc distance from shore.

ACKNOWLEDGMENTS

The investigation was supported (in part) by

PHS Training Grant No. 5 TI 41 from the Na-

tional Intitute of Allergy and Infectious Diseases,

U.S. Public Health Service, Washington, D.C.

The assistance of Henry van der Schalie and

Elmer G. Berry, curators in the Mollusk Divi-

sion, Museum of Zoology, University of Michi-

gan is gratefully acknowledged. The work in the

field was supported by several members of the

Mollusk Division and my family.

LITERATURE CITED

Brackett, Sterling. 1940. Studies on schistosome dermatitis.

VIII. Notes on the biology of the snail hosts of schistosome

cercariae in Wisamsin and epidemiological evidence for life

cycles of some avian schistosomes. Amer. J. Hyy.. 32: 85-104.

Cheatum, Elmer P. 1934. Limnological investigations on

respiration, annual migratory cycle, and other related

phenomena in fresh-water pulmonate snails. TVan.s. Micros.

Soc. 53: 348-407.

Clampitt, P. T. 1972a. Seasonal migrations and other

movements in Douglas Lake pulmonate snails (Abstract).

Malacol. Review, 5(1): 11-12.

Clampitt. P. T. 1972b. Seasonal migratory cycle and related

movements of the freshwater snail Physa integra

(Pulmonata: Basommatophora) (Abstract). Bull. Ecol. Soc.

.4mpr.. 53(2):21.

Michigan Department of Natural Resources. Institute for

Fisheries Research. 1950. Lake Inventory Map: Lake Ann.

Wall, Robert C. 1968. An analysis of the current status of

schistosome dermatitis problem in Mighigan. Doctoral

Thesis. University of Michigan.

Walter. Harold J. 1969. Illustrated biomorphology of the

"angulata" lake form of the Basommatophoran snail. Li/m-

luwn ratn.'^rdpiiim Say. Mnlncnl. Rev.. 2: 1-102.

LIVING MARINE

MOLLUSCS

C. M. Yonge and T. E. Thompson

BEHAVIOUR

Two distinguished British marine biologists have combined their knowledge and talents to

produce a compact, well-rounded account of the largest marine group of animals.

"The first modem book on the biology of marine mollusks

that is of textbook quality, yet so beautifully written

and illustrated that the legions of amateur conchologists

will readily absorb its wealth of information"— R. Tucker

Abbott, Ph.D.

Send check or money order to:

American Malacotogists, Publ.

P.O. Box 4208

Greenville, De. 19807 U.S.A.

Available

1977

Cldthbound, 288 pp., 162 text figures, 16 plates with 18 glorious color photographs of living

marine molluscs. Only $13.95.

52 THE NAUTILUS

April 25,1977

Vol. 91 (2)

FREQUENT SCALARIFORMY IN A POPULATION OF

THE POND SNAIL, LYMNAEA STAGNALIS

Eva Pip

Department of Botany

University of Manitoba

Winnipeg, Manitoba

Canada R3T 2N2

ABSTRACT

T7VI) populations of Lymnaea stagnalis that had been exposed to chronic low-

level (jammn radiation in situ were examined for the presence of shell ab-

normalities. One population shoived no abnonnalities. In the other population

sea la ri form y UHhs found at a frequency of 0.5%, and occurred nmsi.-itentlij in ini-

tiallti non-scalar shells. Gnmnin mdintinn )'.s apparently nut a direct cause if

scidarifiruiy.

Scalariformy in natural populations of Lym-

naea stiujuulis (Linnaeus) is normally a rare and

isolated occurrence, the causes of which are

unknown. Studies of this phenomenon are dif-

ficult because of the very few, scattered and poor-

ly documented specimens known to be in ex-

istence (Pip, 1975) and because the probability of

recurrence in wild populations that have pro-

duced such individuals is too low to merit obser-

vation. However there is evidence that popula-

tions showing a relatively high frequency of

scalariformy exist. F. C. Baker (1911) cited a

population sample from Spoonbill Slough, Deuel

County, South Dakota, that contained several

scalariform individuals. This study documents the

discovery of another such population of L.

stmjncdis. Perhaps coincidentally, this population

has been exposed to chronic low-level gamma

radiation.

METHODS

The study sites were located in an area, 1 km

in diameter, of mixed boreal forest that had been

reserved in the late 1960's for a radiation ecology

study within the Whiteshell Nuclear Research

Establishment's controlled area near Pinawa in

eastern Manitoba. Chronic gamma radiation

began in early 1973 by a 10,000 effective curie '"

Cs source located at the top of a 20 m tower

placed at the center of the area (Dugle and

Thibault, 1974). Irradiation continued at an

average of 19 hours per day. By the end of

August, 1975, the area had received a total of

17,000 hours of irradiation. The western portion

of the area contained numerous small shallow

ponds that had originated as gravel excavations

prior to 1965. Of these ponds, two contained

populations of Lymnaea stagnalis, their centers

located 300 m (site 1) and 480 m (site 2) from the

irradiator respectively. Site 1 was densely col-

onized by cattails (Typha latifolia); small patches

of open water contained the pondweeds

Potamogeton gramineus, P. pectinatus and P.

nutans (nomenclature after Scoggan, 1957). The

mean dose rate at site 1, estimated during the

growing season by lithium fluoride dosimeters

placed 1 m above the center of the pond's surface,

was 12.428 mrad/h. Site 2 was much more ex-

posed: there was no emergent vegetation except

for one small stand of cattails. The sparse

submerged vegetation consisted of Potamogeton

fnliosvs and a species of the algal stonewort

Chara. The mean dose rate 1 m above the center

of the pond's surface was 3.082 mrad/h. Because

of the pond's exposure, water temperatures dur-

ing midsummer reached 30 C. Although both

ponds were less than 1 m deep, temperatures at

site 1 were consistently lower because a large

proportion of the water surface was shaded. Sur-

face water samples collected in July, 1975 were

analyzed according to methods recommended

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 58

by the American Public Health Association

(1971). The two sites showed few differences in

the monitored variables: pH 7.7 - 8.7, total

filtrable residue 135 mg/1, alkalinity 80 mg

CaCOj/l, sulphate 0 mg/1, chloride 0 mg/1, nitrate

1 mg/1, orthophosphate 2 mg/1 (site 1) and 7

mg/1 (site 2). Besides L. xtagnali.^ site 1 also con-

tained Staynicola pal ustris while site 2 contained

S. palustris and Physa gyrina.

During the 1975 season all visible live and dead

individuals of L. stagnalis at the two sites were

scored for presence or absence of shell ab-

normalities. Individuals of other species were ex-

amined as well.

RESULTS AND DISCUSSION

The small populations of L. stagnaliji and S.

palustris at site 1 showed no evidence of mor-

phological abnormalities. The larger population of

L. stagnalis at site 2 showed a constant frequency

of scalariformy during the 1975 season of 5 per

1000 individuals. Scalariformy occurred con-

sistently in initially non-scalar shells (Fig. 1), a

characteristic noted in previous reports (Pip and

Paulishyn, 1970; Jackiewicz, 1972; Pip, 1975).

Onset of scalariformy was abrupt and well-

defined. In approximately 75% of the affected in-

dividuals, scalariformy commenced in the fourth

and fifth whorls. In the remainder of specimens

scalariformy was apparent earlier; in some in-

dividuals it occurred as early as in the second

4444

FIG. 1. Scalariform shells of Lymnaea stagnalis cnlleeted nt

site 2 in Manitoba, Canada, during 1975. i'/>

whorl. One specimen showed onset of scalari-

formy in the sixth whorl; this was the only

specimen where mechanical injury to the shell

was apparent. Scalariformy was frequently ac-

companied by curvature or breakage of the shell

axis. Other aberrations were not observed in L.

sta/inalis. The small populations of S. palustris

and P. gyrina at site 2 were morphologically nor-

mal.

The unusually high frequency of scalariformy

at site 2 is difficult to explain. Because site 1

received 4 times the mean dose rate of site 2,

with no scalariformy or other abnormalities

recorded, radiation appears to be an unlikely

direct cause. Radiation may have contributed

towards the stress already placed on the

organisms by elevated temperatures. The two fac-

tors are related in that elevated temperatures in-

crease the time breathing at the surface

(McDonald, 1973). Since attenuation of radiation

with increasing water depth is considerable, the

snails are exposed to the maximum dose rate

when they are at the surface. The additional ex-

posure to radiation, combined with the effects of

heat stress, may result in some disturbance to

growth. Because scalariformy occurs, as a rule,

relatively late in the development of the snail,

the causative agent is not operating at the

nuclear level. Verdonk (1973) has shown that in

L. Stagnalis few gene deficiencies become active

beyond the veliger stage. It is therefore likely

that mechanical or physiological agents are

among the responsible factors. The occurrence of

Cham at site 2 is interesting in that Geyer (1929

in Jackiewacz, 1972) and Pip (1975) have noted

the presence of this alga in habitats where

scalariform snails have been collected. Further

study is necessary before this phenomenon is

understood.

ACKNOWLEDGMENTS

I would like to thank Drs. J. Dugle and J.

Guthrie of the Whiteshell Nuclear Research

Establishment for their advice and encourage-

ment during the pursuit of this problem.

54 THE NAUTILUS

April 25.1977

Vol. 91 (2)

LITERATURE CITED

American Public Health Association. 1971. Standard Method'^

for the Eiaminatifm of Water and Wastewaters.^. 874 pp.

Baker. F. C. 1911. The Lymnaeidae of North and Middle

America. Ot icago Acad. Sri. Spec. Pub. No. .y. 539 pp.

Dugle. J. R. and D. H. Thibault. 1974. Ecology of the Field

Irradiator-Gamma area, 111. Revisions to botanical methods

and vegetation sampling procedures (AECL-41.3.5). Atomic

Energy of Canada Limited, report AECI^4668. 41 pp.

Jackiewicz. M. 1972. Anormalnosci w budowie shorupki

niekorych mi^zakow wodnych. Przeglad Zoologiczny 16:1:

95-98. (in Polish).

McDonald, S.C. 1973. Activity patterns of Lymnaea atagnalis

(L.) in relation to temperature conditions: a preliminary

study. Malacolngia 14: 39,5-396. Abstract only.

Pip, E. 1975. Scalariformy in the pond snail. Li/mnaea

stagnalis. The Nautilus 89: 36-37.

Pip, E. and W. F. PaulishvTi. 1970. Unusual fr«sh water

mollusk collected. Hawaiian Shell News 18: 11: 6.

Scoggan, H. J. 19.57. Flora of Manitoba. Nai. Mus. Canada,

Bull. No UO, 619 pp.

Verdonk. N. H. 1973. Gene expression in early development of

Lifmnof a stagnalis. Devel. Buil. 35: 29-35.

SHELL SIZE-FREQUENCY DISTRIBUTIONS OF CORBICULA

MANILENSIS PHILIPPI FROM A CLAM-FOULED

STEAM CONDENSERS

Robert F. McMahon

Department of Biology

TTie University of Texas at Arlington

Arlington, Texas 76019

ABSTRACT

Specimens and empty whole and half ahelh of the introduced Asiatic freshwater

clam. Corbicula manilensis, were collected from the inlet (cold water) box. con-

denser tubes and outlet (warm water) box of a clam-fouled steam condenser of an

electric generator utilizing raw water from Lake Arlington, Texas. Size-frequency

distributions of length, height, and width of shells removed from these three sec-

tions indicated that the clams were not growing in the condenser but had been

carried into it with intake currenUi from an external population in the intake em-

bayment and tunnel. It appers that the condenser tubes acted as a sieve becoming

fouled only unth shells of an appropriate size to become lodged in the tubes while

smaller specimens passed thnmgh and larger shells were retained in the inlet box.

It is siHjge.'ited that increasing tube inside diameter to 29.0 mm or mitre icill (illmr

even the largest specimens of C. manilensis to /la.w thnoigli cinidniscrs mid

therehii a void fouling problems with th /.s' species.

The introduced Asiatic freshwater clam, Cor-

bicula manUetisis. was first recorded in the Col-

umbia River, Washington, in 1938 and has since

spread through a large portion of the freshwater

' Supported by grant number 16-6.53 from Organized Research

Funds of The University of Texas at Arlington to Robert F.

McMahon.

environments of the southern United States

(Sinclair, 1971, and references within). The high

reproductive capacity and fast growth of this

clam has allowed it to become a major pest

species in many drainage systems (Ingram, 1959;

Sinclair and Isom, 1961. 1963; Sinclair, 1963, 1964,

1970; Prokopovich and Herbert, 1965; Prokopo-

vich, 1969). Recently C. manilensis has been

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 55

reported to have fouled raw watercooled steam

condensers of electric generating and other in-

dustrial facilities in several regions of the United

States (Ingram, 1959; Sinclair and Isom, 1961.

1963: Sinclair, 1963, 19&4, 1970; Thomas and

MacKenthun, 1964; Thomerson and Myer, 1970;

Diaz, 1974). This report describes the distribu-

tions and means of shell size for specimens of C.

manilerms collected from a clam-fouled steam

condenser of an electrical generator and proposes

a possible design solution to the problem of foul-

ing by the shells of this species.

MATERIALS AND METHODS

On 12 January, 1976, whole specimens and

whole and half shells of Corbieida manilensis

were collected from the clam-fouled steam con-

denser of the Number Two electrical generator of

the Handley Steam-Electric Generating Plant,

maintained by the Texas Electric Service Com-

pany on Lake Arlington, Texas (USGS map

quadrangle, Arlington, 32° 43' 15" N: 97° 12' 57"

W). This plant utilizes raw lake water as a

coolant for the steam condensers of its three

generating units. The maximum flow of lake

water through the condensers is 1.298X10* liters

per minute (1.870X10' 1/day) and the monthly

average discharge rate is 1.052X10* 1/per minute

(1.514X10' 1/day (Hall, 1972; McMahon. 1975).

The clams were collected from three areas in the

steam condenser: the inlet or cold water box

(CWB) which receives raw lake water for cooling

from the intake canal; the condenser tubes (CT)

which carry water from the CWB and which are

used to cool and condense the steam passed over

them before it is returned to the generator's

boilers: and the outlet or warm water box

(WWB) which receives warmed water from the

condenser tubes. Water is passed from the WWB

to the discharge canal and is then returned to the

lake (for a more complete description of the

Handley Power Plant's operation see McMahon,

1975).

The condenser tubes of the Number Two

gererator have an outside diameter of 22.2 mm,

an inside diameter of 19.7 mm and a tube wall

thickness of 1.24 mm. The Number Two generator

is a "peaking" unit which operates only during

periods of high demand. It has an output of 80

MW and a maximum flow through its condenser

of 132,469 1/min. Average water velocity in the

intake tube to the condenser is 2.44 m/min and

velocity increases to 2.26 m/sec in the condenser

tubes.

C. manilenda was first observed in Lake Ar-

lington during the spring of 1973 (John Barnett,

personal communication) and it first fouled the

Number Two condenser at the Handley Power

Plant in the summer of 1974. Since that time the

Number Two unit has been shut down several

times in order to remove C. manilensis shells

from its condenser tubes. Such fouling has never

occurred in the larger Number Three unit, a con-

tinuously running "base load" generator, with an

output of 400 MW and a water flow through its

condensers of 435,322 1/min. This unit's water

velocities are similar to that of the Number Two

unit, but the condenser tubes are larger with an

outside diameter of 25.4 mm, an inside diameter

of 22.9 mm and a tube wall thickness of 1.24 mm.

Living specimens and empty whole and half

shells of C. manilensis were collected from the

Number Two condenser 72 hours after the

generator had been shut down on January 9,

1976. Samples were randomly removed from each

of three areas (CWB, CT and WWB) and re-

turned to the laboratory. For each individual in

each sample three shell dimensions were meas-

ured to the nearest 0.05 mm using a dial microm-

eter. The shell dimensions recorded were: shell

length (SL), the greatest dimension anterior-

posterior across the shell; shell height (SH) the

greatest dimension dorsal -ventral across the shell

from the umbones to the ventral edge of the

valves: and shell width (SW), the greatest lateral

dimension between the two valves (for single

valves shell width was estimated by multiplying

the greatest lateral dimension by two). No sig-

nificant differences occurred in the mean dimen-

sions of whole and half shells in each sample (P

> 0.10); therefore, the dimensions of whole shells

and single valves were combined, allowing the

computation of a mean SL, SH and SW with cor-

responding standard deviations for each of the

three samples (CWB, CT. WWB). The distribu-

tions of sample shell dimensions from all three

56 THE NAUTILUS

April 25,1977

Vol. 91 (2)

collection sites were then compared for sig-

nificance using students' t test.

RESULTS

Figures one, two and three illustrate the shell

size distributions of C. nunulrnsis collected from

the cold water box (CWB) (Fig. 1), the condenser

tubes (CT) (Fig. 2) and the warm water b)X

(WWB) (Fig. 3) of the Number Two steam con-

denser. Approximately 20-30% of the shells

removed from each of the three portions of the

condenser contained intact soft parts. There was

no evidence of byssal attachment by the clams to

tube walls or any other portion of the condenser

as has been previously suggested for fouling by

this species (Sinclair and Isom, 1961, 1963).

The 122 shells collected from the intake or cold

water box (CWB) had a mean SL of 21.1 mm (s.d.

= ±6.19 mm, range = 5.7 - 33.(S mmj.a mean SH

of 19.98 mm (s.d. = ±5.29 mm, range = 4.9 - 28.1

— I r

CWB

10 15 20 25

SHELL LENGTH in mm

FIG. 1. Lfiujth frequency distrihutiona of Corbiciihi

niiinilensis sheik collected from the inlet or cold water box

(CWB), condenser tubex (CT) and outlet or warm ivater box

(WWB) of a steam condenser utilmng raw lake water as a

roolivit. The vertical axis is per cent of total sample mimhers

and the hwizontal axis is shell length (SL) in millimeters.

The darkened circles represent mean shell lengths for each

s<tmple and bars aboid the means, .itandard deirialions. Tlie

.■itipled vertical line represents the inside diameter (19.7 mm)

of the condenser tubes.

1 r

10 15 20 25

SHELL HEIGHT In mm

FKi. 2. Height freqnencii distributions of C. nianilensis

■fhells collected from the inlft or cold unter btix (CWB), con-

denser tubes ((JT) and outlet or warm box (WWB) of a steam

coiuietiser utilizing raw lake water as a coolant. The vertical

axis is per cent of total sample numbers and the horizontal

axis is shell height (SH) in millimeters. The darkened circles

represent mean shell heights for ench somplc and the liars

about the means, statutard deiiations. The stipled vertical line

represents the inside diamenter (19.7 mm) of the condenser

tubes.

mm) and a mean SW of 12.37 mm (s.d. = ±3.48

mm, range = 3.8 - 20.0 mm). Corresponding

mean shell dimensions for the 51 shells removed

directly from the condenser tubes were: mean SL

= 24.4 mm (s.d. = ±4.17 mm, range = 10.6 -

32.0 mm); mean SH = 20.95 mm (s.d. = ±3.74

mm, range = 8.2 - 27.8 mm); and SW = 14.22

mm (s.d. = ±2.41 mm, range = 6.1 - 18.8 mm)

(Fig. 2). Mean dimensions for the sample of 150

shells drawn from the warm water box (WWB)

were: mean SL = 16.72 mm (s.d. = ±3.75 mm,

range = 4.6 - 23.1 mm); mean SH = 14.28 mm

(s.d. = ±3.75 mm, range = 3.4 - 19.7 mm); and

mean SW = 9.89 mm (s.d. = ±2.17 mm, range

= 2.7 - 13.6 mm) (Fig. 3). The shell sjimples

drawn from all three regions of the condenser

(CWB, CT. WWB) were significantly different

from each other (P <(U)5) in all three dimen-

sions measured (SL, SH, SW).

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 57

DISCUSSION

Since 1960 there have been a series of reports

recording the fouling of water-cooled steam con-

densers by C. manilensds in both steam-electric

power plants and other industrial facilities

(Ingram, 1959; Sinclair and Isom, 1960, 1963;

Sinclair, 1963, 1964, Thomas and MacKenthun,

1964; Thomerson and Myer, 1970, Diaz, 1974).

Several of these reports suggest that C. manilen-

ds attach as young by a byssus to the walls and

insides of tubes carrying cooling water in the

condensers (Sinclair, 1963, 1964; Sinclair and

Isom, 1960, 1961). Unlike these previous reports

no small clams (SL < 5 mm) and no evidence of

byssal attachment could be observed in any part

of the Handley Power Plant's Number Two con-

denser even though living clams with intact soft

parts represented a significant proportion of all

three samples.

A comparison of the size distributions of the

three samples indicates that the clams fouling the

condenser are not a resident population, but in-

stead, must have been carried into it from an ex-

ternal population. The distribution of SL in the

CWB had a mean of 21.1 mm. (s.d. = ±6.19 mm)

(Fig. 1) which was significantly different (P <

0.05) from the distributions of SL of both the CT

and WWB. The distribution of SH in the sample

of C. manilensis shells dravm from the condenser

tubes was significantly different from both the

samples taken from the CWB and WWB (Figs. 1,

2 and 3) and had a mean SH of 20.95 mm and a

rather narrow distribution of shell height about

the mean (s.d. = ±3.74 mm) (Fig. 2). The inside

diameter of the Number Two unit's condenser

tubes at 19.7 mm is almost equal to the mean SH

(20.95 mm) of the shells sampled from them. As

shell height (SH) approximately represents the

smallest diameter across the plane between the

two valves, these data appear to indicate that C.

manilensis shells are transported into the con-

denser tubes and only those of an appropriate

size (i.e., an SH closely approximating the inside

diameter of the tube) would become lodged in the

tubes at points of slight constriction (primarily at

regular bends in the condenser tubing). The few

smaller shells (SH < 17 mm) found in the con-

denser tubes were taken from tubes already oc-

SHELL WIDTH in mm

FIG. .3. Width frequency distributions of C. manilensis

shells collected from the inlet or cold water box (CWB). con-

denser tubes (CT) and outlet or warm water box (WWB) of a

steam condenser utilizing raw lake water as a coolant. The

vertical axis is per cent of total sample numbers and the

horizontal axis is shell width (SW) in millimeters. The

darkened circles represent mean shell widths for each sample

and the bais about the means, standard demations. The

stipled vertical line represents the inside diameter (19.7 mm)

of the condenser tubes.

eluded with larger wedged shells which prevented

their passage. In the outlet or warm water box

(WWB) only shells with a SH less than the inside

diameter of the condenser tubes (SH < 19.7 mm)

were taken (Fig. 3), the sample from this area

having significantly smaller shell dimensions (P<

0.05) than the samples from both the CWB and

CT. Thus, it appears that the shells in the WWB

must be carried from the CWB through the con-

denser tubes to the WWB and that only clams

with an SH smaller than the inside diameter of

the condenser tubes may pass through them. In-

gram (1959) has reported a similar accumulation

of C. manilensis shells in tubes with an inside

diameter of 15.8 mm from a condenser in Califor-

nia.

In this sense the condenser acts as a sieve.

Clams are drawn into the CWB from an external

population with intake currents and therefore

58 THE NAUTILUS

April 25.1977

Vol. 91 (2)

shell size distributions in this are are represent-

ative of those in natural Lake Arlington popula-

tions of C. manilensis (Aldridge, 1976). Of those

shells drawn into the CWB those with SH's of

less than the inside diameter of the condenser

tubes eventually pass through the condenser to

the discharge canal leaving the largest shells in

the CWB. The condenser tubes themselves become

initially fouled only with those shells with a SH

approximately their inside diameter. These shells

apparently become lodged at slight constrictions

in the tubes or at bends in the tubes. Water

velocities in the condenser tubes at 2.26 m/sec

are probably much too great to allow veliger set-

tlement and therefore shells must be transported

into this portion of the condenser.

Relatively dense populations of C. manilensis

occur both in the intake canal of the power plant

and in the shallow shore areas of Lake Arlington

(Aldridge, 1976). Throughout the year living

specimens of C. manilensis in Lake Arlington

have been observed to move entirely out of the

substrate and be carried over the bottom by cur-

rents and wave action. Similar observations have

been made for a C. manUensis population on the

James River, Virginia (R. J. Diaz, personal com-

munication). C. manilensis may move out of the

substrate when environmentally stressed and be

carried by currents in the pwwer plant's intake

canal to traveling screens in front of the intake

tunnels to the condensers. The traveling screens

of the Handley Power Plant on Lake Arlington

have a mesh size of 12.7 mm which prevents

clams large enough to foul the condensers from

entering the intake tunnels. However, smaller

clams with an SH less than 12.7 mm, spat and

veligers will pass easily over the screens. If these

clams settle in the embayments behind the

screens or in the intake tunnels where water cur-

rents are relatively slow (2.44 m/min) they will

grow very rapidly and reach an SH large enough

to allow them to lodge in condenser tubes (ap-

proximately 19 mm) in two to six months (Al-

dridge, 1976). Thereafter, if the quality of lake

water drawn into the intake canal is lowered by

natural means (i.e., high summer temperatures or

low oxygen concentration) or as the result of

human activity (shock chlorination and other per-

turbations) the now resident Corbicida popula-

tions behind the screens may move out of bottom

slits to be carried by intake currents into the

condensers. Such populations of adult C. manilen-

sis have been observed behind the traveling

screens at the Handley Power Plant on Lake Ar-

lington (M. W. Zengerle, personal communica-

tion).

It has been reported that adult C. manilensis

are not susceptible to shock chlorination as a

method of control (Sinclair and Isom, 1960, 1961;

Sinclair, 1963, 1964); instead, constant chloration

of intake waters at levels of 1.5-10 ppm (up to 50

ppm for two weeks) have been recommended as a

means of preventing this species from impinging

upon condensers (Sinclair and Isom, 1960, 1963;

Sinclair, 1963, 1964). Present Environmental Pro-

tection Agency regulations generally prohibit

constant chlorination of raw intake water used

for cooling purposes and shock chlorination may

actually enhance condenser fouling by stressing

resident populations.

It is notable that the larger Number Three

generating unit at the Handley Power Plant on

Lake Arlington has never had its steam con-

densers fouled with C. manilensis. The only

discemable difference in the operation of its con-

densers and those of the often-fouled Number

Two unit is that the inside diameter of its con-

denser tubes is larger at 22.9 mm (see Methods).

As such it would only stop clams with an SH

greater than 22 mm which represents only about

1.51% (s.d. = ±2.22%, range 0 - 8.9%, N = 28) of

the normal Lake Arlington C. manilensis popula-

tion over 1975 while the Number Two unit's con-

denser tubes have a smaller inside diameter (19.7

mm) and would stop about thirteen times as

many clams (19.45%, s.d. = ±13.41%, range =

3.7 - 64.4%, N = 28) (Aldridge, 1976). Since so

few clams of the appropriate size for fouling im-

pinge upon this larger unit's steam condenser (in-

side diameter 22.9 mm), it is hypothesized that

the high water velocities in its condenser tubes

abrade and break up lodged shells at a rate

which prevents serious fouling. In contrast, a far

greater number of appropriately sized shells im-

pinge on the smaller tubes of the Number Two

unit's condenser (inside diameter = 19.7 mm)

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 59

allowing a steady accumulation of lodged shells

in the condenser tubes, eventually impairing the

condenser's efficiency.

It may be possible to avoid Corbindn fouling in

water-cooled steam condensers of future electrical

generating and industrial facilities by designing

steam condensers with condenser tubes of inside

diameters greater than 29.0 mm, the approximate

SH of a specimen of C. manUends 50 mm in shell

length (Aldridge, 1976). A specimen of this shell

length (50 mm) was the largest ever taken in over

a year of bi-weekly collections of ('. mariilcusix

on Lake Arlington (Aldridge, 1976) and is

roughly equal to or less than the maximum shell

lengths reported for other populations of this

species near fouled condensers (Sinclair and Isom,

1961, 1963; Sinclair, 1963, 1964; Thomas and

MacKenthun, 1964; Thomerson and Meyer, 1970;

Diaz, 1974). Therefore, designing condensers

which would allow passage of even relatively

large specimens of C. manilensis (inside diameter

of condenser tubes > 29.0 mm) might eliminate

all possiblity oiCorbicula fouling.

ACKNOWLEDGMENTS

I wish to express my deep appreciation to Mon-

ta Zengerle, Texas Electric Service Company

Biologist, who allowed me to be present when the

condenser was inspected and who supplied data

on the steam condenser's operation; to David W.

Aldridge for his advice and discussions on the

biology of C. manilensds; and to Nancy B. Banks,

for her assistance with the preparation of the

manuscript.

LITERATURE CITED

Aldridge, D. W. 1976. Growth, reproduction and bioener-

getics in a natural population of the Asiatic freshwater

clam, (hrbinda manilen.tis Philippi. Maiytfr'n Thexis. TTie

University of Texas at Arlington. 93 pp.

Diaz. R. J. 1974. Asiatic clam, Girhinda manUends (Philippi).

in the Tidal James River, Virginia. Chesapeake Si-i. 15:

118-120.

Hall. F. M., III. 1972. Species diversity and density of the ben-

thic macroinvertebrates inhabiting a reservoir receiving a

heated effluent. Master's The^s. The University of Texas at

Arlington. 82 pp.

Ingram, W. M. 19.59. Asiatic clams as potential pests in

California water supplies. Jour. Amer. Water Works Assoc.

51: 36.3-.369.

McMahon. R. F. 1975. Effects of artificially elevated water

temperatures on the growth, reproduction and life cycle of

a natural population of Physa iri.rgata Gould. Ecology 56:

1167-1175.

Prokopovich, N. P. 1969. Deposition of clastic sediments by

dam&.JmrSed. Petrology 39: 891-901.

Prokopovich, N. P. and D. J. Hebert. 1965. Sedimentation in

the Delta-Mendota Canal. Jour. Amer. Water Works Assoc.

57: 375-382.

Sinclair, R. M. 1963. Kfects of an introduced clam (Corbicula)

on water quality in the Tennessee River Valley. In Pro-

ceedings of the Second Indiistnal Waste Conference.

Vanderbilt University. Tennessee Department of Public

Health. Tennessee Stream Pollution Control 3oard. pp.

43-50.

Sinclair, R. M. 1964. Clam pests in Tennessee water supplies.

Jour. Amer. Water Works Assoc. 56: 592-599.

Sinclair, R. M. 1971. Annotated bibliography on the exotic

bivalve Corbieida in North America, 1900-1971. Sterkiana

40: 11-18.

Sinclair. R. M. and B. G. Isom. 1%1. A preliminary report on

the introduced Asiatic clam Corbiada in Tennessee. Ten-

nessee Stream Pollution Control Board. Tennessee Depart-

ment of Public Health. 31 pp.

Sinclair. R. M. 1963. Further studies on the introduced

Asiatic clam in Tennessee. Tennessee Stream Pollution Con-

trol Board. Tennessee Department of Pulbic Health. 51 pp.

Thomas. N. A. and K. M. MacKenthun. 1964. Asiatic clam in-

festation at Charleston. West Virginia. The NautUus 78:

28-29.

TTiomerson, J. E. and D. G. Myer. 1970. Corbiada manilensis:

Range extension upstream in the Mississippi River.

Sterkiana 37: 29.

60 THE NAUTILUS

April 25,1977

Vol. 91 (2)

ABNORMAL HYPERSTROPHY IN LITTORINA UNEOLATA

(GASTROPODA: LITTORINIDAE)

M. G. Harasewych

College of Marine Studies

University of Delaware

Newark, Delaware 19711

ABSTRACT

A specimen of Littorina lineolata Orbigny from Oistint^ Bay. Barbados was

found to have a normal orthostrophic protoconch and an abnormal.

hypertrophic teleoconch. based on examination of anatomy, shell, protoconch

and (rperculum. This is believed to be the first report of such an abnormality in

gastropod'^.

The occurrence of anomalous shell mor-

phologies is well documented in the Littorinidae

of tropical as well as boreal waters (Rosewater,

1972). It was therefore not too surprising to

discover what appreared to be a sinistral

specimen of Littorina lineolata Orbigny. 1840

while sorting material collected in Oistins Bay,

Barbados. Closer examination, however, revealed

this specimen to be dextral and hyperstrophic.

It is necessary at this point to make a distinc-

tion between asymmetry of the shell and asym-

metry of the soft parts. The terms dextral and

sinistral, in the strict sense, refer to the orienta-

tion of organ systems in the gastropod body. The

vast majority of prosobranchs are dextral and

have lost the osphradium, ctenidium, hypobran-

chial gland and auricle on the post -torsional right

side of their body. This was accompanied by a

shifting of the anus to the right side of the body

and modification of the right kidney into a

reproductive organ. The reverse is true of

sinistral gastropods, which are mirror images of

their dextral counterparts. Dextrality or

sinistrality is detectable as early in development

as the late two cell stage (Crampton, 1894), long

before even the first appearance of a shell.

The terms orthostrophy and hyperstrophy refer

to the orientation of the asymmetrical shell with

regard to the soft parts. The term orthostrophic is

applied to gastropods in which the spire is on the

same side of the body as the anus and pallial

reproductive organs, while the term hyper-

strophic is applied to gastropods in which the

spire is on the same side of the body as the un-

paired osphradium, ctenidium, hypobranchial

gland and auricle. Tlie direction of coiling is

determined in the larval stage, but, in some gas-

tropods, is changed at the time of metamorphosis

(e.g. Architectonicidae, Pyramidellidae).

Robertson and Merrill (196;3) reported the ab-

normal occurrence of post -larval hyperstrophy in

two species of Heliarus. in which the normal

hyperstrophy of the protoconch was abnormally

retained by the teleoconch. The specimen of Ldt-

torina lineolata discussed here, however, is be-

lieved to be the first reported occurrence of a gas-

tropod with a normal orthostrophic protoconch

and an abnormal hyperstrophic teleoconch. This

specimen (figure 1), in the collection of the

Academy of Natural Sciences of Philadelphia

(ANSP no. 342287), was compared to normal

specimens from the same locality (ANSP no.

342286) and proven to be dextral and hyper-

strophic on the basis of the following evidence.

Anatomy. Tissue as far up as the rear of the

mantle cavity was well preserved. The orientation

of the mantle cavity organs was that of a de.xtral

animal, the anus and capsule gland being on the

right side of the body, while the osphradium,

ctenidium and hypobranchial gland were on the

left.

Operculum. As demonstrated by Pelseneer

(1893, fide Robertson and Merrill, 1963), the

direction of coiling of the operculum can be used

to distinguish between dextral and sinistral

animals, the former producing opercula which

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 61

FIG. 1. .4, luirmiil apecunen nf Littorina lineolata Orbigny

fmm Oistins Bay. Barbados. x2. B. Hifperstrophic specimen

from the .same locality. xS.

coil counter-clockwise when viewed externally,

and latter produce opercula which coil in the

clockwise direction when viewed externally. The

operculum of the specimen in question (figrure 2)

is coiled in the counter-clock-wise direction, in-

dicating that the animal which produced it was

dextral.

ProtoctDirh. As there is considerable pitting of

the early whorls, it is not possible to locate the

exact boundary between protoconch and

teleoconch stages, but there is clearly a change in

the direction of coiling of about 140 degrees bet-

ween the axis of the early whorls of the pro-

toconch and the axis of the adult shell (figure 3),

indicating that the specimen was initially dextral

FIG. 2. Ertenial mew of operadum of the hifperstrophic

Littorina lineolata. xlO.

FIG. 3. Early whorls of the hifperstrophic Littorina lin«)-

lata. xl2.

and orthostrophic but became abnormally

hyperstrophic near the time of metamorphosis.

Shell. There are two major shell characters

which attest to the hyperstrophy of this

specimen: the location of the major spiral cords

relative to the shoulder, and the direction of the

brown axial bands relative to the columella. Nor-

mal specimens are characterized by having 11 or

12 major spiral cords on the apical side of the

shoulder and a variable number of very fine

spiral threads on the adapical side of the

shoulder. This situation is reversed in the

hyperstrophic specimen, the fine spiral threads

being located on the apical side, while 11 major

spiral cords are located on the adaptical side of

the shoulder. When viewing the orientation of

the brown axial lines relative to the columella, it

can be seen that in normal individuals the brown

bands approach the columella tangentially, while

in the hyperstrophic specimen the bands appear

to be almost perpendicular to the columella.

It should be noted that the actual shape of the

aperture relative to the animal is not very

drastically changed, the left side being more

spacious than the right. This would have de-

creased the compression of the ctenidium, which

would have been a serious impediment to the sur-

vival of the organism.

I thank Dr. Robert Robertson (Academy of

Natural Sciences of Philadelphia) for reviewing

the manuscript.

62 THE NAUTILUS

April 25.1977

Vol. 91 (2)

LITERATURE CITED

Crampton, HE. 1894. Reversal of Qeavage in a Sinistral

Gastropod. Annals N. Y. Aaui. Sci 8: 167-170. pi. .5.

Pelseneer. P. 1893. A propos de 1' "Asymetrie des Mollusques

univalves." Jtmrn. Qmchyliologie iO: 229-23.3, 1 fig.

Robertson. R. & Merrill, A.S. 196:?. Abnormal Dextral

Hj^perstrophy of Post-Larval Heliacius (Gastropoda: Ar-

chitectonicidae). The VeliyerG: 76-79, pi. 13-14.

Rosewater, J. 1972. Teratologicai Littorina scabra angulifera.

The Nautilus 86: 70-71. 6 fig.

FOUR OPISTHOBRANCHS LIVING ON MARINE ALGAE

FROM WEST MEXICO

Leroy H. Poorman and Forrest L. Poorman

Los Angeles County Museum of Natural History

Los Angeles, California 90007

ABSTRACT

Field notes on Lobiger souverbii, Oxynoe panamensis, Berthelina chloris,

and Phyllaplysia padina, nil from HV,s-/ Mexico, are munmarized. 77n'.s' inrlndetf

descn{jtion,s of the living animals and obseirations on their habits and habitats.

Range extensdons northwaM into the Gulf of California are recorded for the

first three species. Geographical rongcs in the Tropical Eastern Pacific arc

<] ircn for all four species.

The last several years have presented op-

portunities for intensive collecting and observa-

tion of Panamic opisthobranchs. Collecting sta-

tions ranged from Cabo Tepoca. Sonora, to Man-

zanillo. Colima. Mexico. Several stations on the

east coast of Baja California at Bahia de Concep-

cion and Bahia de Los Angeles were visited.

Opisthobranchs were observed and photographed

in the field and in aquaria. Numerous species

were preserved and are on deposit at the Natural

History Museum, Los Angeles County, California.

Copies of 35 mm slides are also on deposit.

A review of our field notes reveals some in-

teresting information on four of the opistho-

branchs living on marine algae. We believe that

these notes and comments will be of some in-

terest and will stimulate further field observa-

tion.

Lobiger souverbii Fischer, 1857

On February 17, 1974, during^ a series of low

tides, we were collecting at Bahia de Tenacatita,

Jalisco. On Caulerpa racemosa var. turbinata

(type 1), which resembles bunches of tiny grapes

(Keen & Smith. 1961), we found 25 specimens of

Lobiger souverbii Fischer, 1857. Several were

crawling over the surface of the Caidoim: but

most were in nests along the lower edge of the

algae, usually adjacent to sand. Sometimes, as

many as five animals were in the same nest. A

number of specimens were kept alive in an

aquarium for several days for observation and

photographing. The living animal is well-figured

in Keen. 1971.

Lobiger souverbii has four parapodia which are

lateral extensions of the foot and are not to be

confused with cerata which are dorsal appen-

dages containing diverticula associated with

digestion. The parapodia are extensions of the

foot below the four corners of the shell and curl

upward. The branches are like long narrow leaves

with ruffled edges. They are a lighter green than

is the body, which is the green of the algae. On

approximately half of the animals observed, there

was an orange band on the upper side of each

branch, inset slightly from the margin. The

Vol. 91

April 25, 1977

THE NAUTILUS 63

parapodia were normally extended upward at an

angle of 45° and were partially rolled inward.

When disturbed, the animals flexed and recurled

these in a rapid cyclic sequence. When oxygen

was depleted, the animals became lethargic and

the parapodia were completely extended horizon-

tally.

The caplike shell is on the dorsum, exactly

between the four branches of the parapodia. Mot-

tled green of the internal organs and a strong

blue veining shows through. When removed from

the animal, the shell is clear but became translu-

cent when dry.

While the animals were in the tank, auto-

tomizing of the parapodia was observed. Several

individuals had previously discarded one or more

of the lobes. No instance of regeneration was ob-

served.

This species appears to be very social. Not only

did several animals share a common nest, but

when 25 specimens were placed in an acquarium,

they at once formed a close group. Within min-

utes, sexual activity was observed, involving two

or more individuals at the same time. Within

hours, the algae was covered with gelatinous

strings containing thousands of microscopic,

spherical yellow eggs.

In December, 1975, we found one specimen of

Lobiger sourerbii sharing a common nest with

two other opisthobranchs. They were on a dif-

ferent type of Caiderpa (type 3) at Bahia de

Algodones, Guaymas Area, Sonora. This is a

northward range extension for the species. The

known range is now from Bahia de Algodones,

Sonora, to Bahfa de Tenacatita, Jalisco, on the

mainland of Mexico. It is also recorded from Cabo

San Lucas, Baja California Sur (Larson & Bertsch,

1974) and from the Galapagos Islands, Ecuador

(Sphon & MuUiner, 1972).

Oxynoe panamensis Pilsbry & Olsson, 1943

A single specimen of Oxynoe panamensis

Pilsbry & Olsson, 1943, was found on the Caider-

pa at Bahia de Tenacatita. Like Lobiger. it had

the ability to cling to the algae by suction of the

foot. When attempts were made to remove the

animal from the algae, a greenish white mucus

was excreted from glands along the side of the

foot. This mucus seemed to have adherent proper-

ties for the animal. It is more probable that the

mucus served as a defense mechanism (Sphon &

Mulliner, 1974).

Oxynoe panamensis was described from a

single shell in the beach drift on Isla Bocas, Golfo

de Panama (7° 30' N, 80° 37' W). The living

animal is figured in Keen, 1971. The body is long,

slender, and slightly humped (30 x 4 x 4 mm).

The first one-fourth of the body is made up of the

head and neck. The second one-fourth comprises

the shell, most internal organs, and two para-

podia, one on each side. The posterior one-half of

the body is the tail. The head is small and blunt

with relatively large, nonretractable, inrolled

rhinophores projecting horizontally from the lat-

eral extremities. The angle between the rhino-

phores is 90-120°. The mouth is on the underside

of the head and is preceded by two rounded lips.

The short neck extends back to the rounded

anterior end of the shell. This is broad and cap-

like on the dorsum and contains most of the vital

organs. Behind the shell, the body tapers narrow-

ly into a sharp tail. There is a ridge extending

from just behind the shell along the back to the

posterior extremity.

Tine foot is extended laterally into two para-

podia which rise upward over the shell to meet

dorsally. Normally, the shell is completely

covered except for the forward edge. The para-

podia extend around the shell to the rear but do

not quite meet until about 1 mm behind, where

they fuse to form the ridge down the back. Ex-

cept for the head, the body and parapodia are

sparsely covered with sharp papillae.

Overall color of the animal is the green of the

algae. The papillae are white and there are small

white dots over the entire animal, most numerous

along the lower edge of the foot and toward the

extremities of the rhinophores. Black spots alter-

nate with white dots along the foot margin and

are scattered with white on the upper one-half of

the rhinophores. Blunt papillae and white spots

are concentrated along the posterior dorsal ridge.

When the parapodia are removed, the internal

organs are revealed through the transparent

shell. The organs are varying shades of green and

clearly show a pattern of white dots.

64 THE NAUTILUS

April 25,1977

Vol. 91

In November, 1974, 32 specimens of Orjfnoe

panmnptifns from 4 to 30 mm in length were col-

lected from a feathery form of Caulerpa (type 2)

at Tinajas, Bahia de Bachwibampo, Sonora. This

algae resembled Calerpa racemosa var. ser-

tularioides reported by Keen & Smith, 1961, from

Lsla Flsp'ritu Santo. One year later, the algae in

the same region had greatly diminished in quan-

tity and deteriorated in quality and only a few

animals were found.

The collected animals were kept in an aerated

aquarium for six weeks. Fresh algae was pro-

vided at intervals. The animals moved about free-

ly on the algae and tank walls, exhibiting the

same social habits as Lobiger except for the flex-

ing of the parapodia. This species seems to be less

e.xcitable than Lobiger. When placed in the tank,

the animals began sexual activity at once. Soon,

the glass walls showed numerous spirally coiled

egg masses containing microscopic, spherical

yellow eggs. Actual laying of the eggs was ob-

served and photographed through the glass as the

egg mass was deposited. One animal moved along

an irregular path with the gelatinous ribbon ap-

pearing from the broad front of the foot to be

deposited on the glass. Two other animals

crowded close on the right side and just behind

the head of the animal that was depositing the

egg mass.

We further noted that Lobiger souverbii from

the southern part of the range was abundant,

with the animals large, brightly colored, and

vigorous; but that the specimen from Bahia de

Algodones was in poor condition. In contrast to

this, ()xi/)io(' paudmcnsis was abundant at

Guaymas. The animals were in fine condition

compared to the single pale specimen from Bahia

de Tenacatita.

Autotomizing of the parapodia, which is not

uncommon with Lobiger. was not observed with

OxifHoe. However, the latter have been reported

able to autotomize the tail section. The actual act

was not observed in our tank; but several tail

sections were found on the bottom of the tixnk

and several animals without tails were observed.

When dropped into alcohol, almost all of the

animals seperated the tail se.lion from the body

at a point just behind the parapodia and the

.shell.

The recorded range for Oxijnoe panamensis is

at lsla Espiritu Santo, Gulf of California, (Keen,

1971). and from the Guaymas area, Sonora. Mex-

ico, to Golfo de Panama (type locality).

BertheIiniachloris(DaIl, 1918)

We were collecting at the south end of Bahi'a

de Algodones on November 29, 1975. At low

water, we were out on the reef, which is 2 or 3

acres in extent. The tangled mass of Caulerpa

(type 3) was encountered for the first time. We

picked up a small rock with a clump of the algae

attached, thinking to e.xamine the holdfast where

we had previously found Sulcoretusa. Nestling

among the branches was what seemed to be a

small green bivalve. When the specimen was

removed to a vial of sea water, a small green

slug-like body emerged and began to crawl about.

There were two valves inverted on its back with

what appeared to be the hinge oriented upward

and to the rear. Four small clumps of the algae

yielded 13 specimens. We knew that we had

found our first Betihelinia chloris (Dall, 1918).

This is a range extension northward from lsla

Espiritu Santo (Keen, 1971). The known range is

now Abreojos to La Paz, Baja California Sur.

Keen. 1971, states that the species possibly occurs

at Guaymas. This is now confirmed. The species

has also been reported from the Galapagos

Islands. Ecuador (Sphon & Mulliner. 1972). The

living animal was illustrated in Sphon & Bertsch,

1974.

When collected, all of the animals were

withdrawn and with the shells closed. One nest in

a cavity in the algae yielded eight specimens.

Several very small individuals were in this nest

and would have been overlooked except that they

were clinging to the shells of the adults. As the

animals were removed, they were found to be at-

tached to the algae with the fine elastic threads

which have been previously reported (Sphon &

Mulliner, 1972). Betihelinia were subsequently

observed to produce large amounts of mucus from

glands along the posterior foot margin. TTie

mucus soon sets, in the salt water, into elastic

threads which the animal spins.

When first placed in the aquarium, the ani-

mals clung together in a tight ball. As they slow-

ly dispersed, the young ones continued to cling to

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 65

the shells of the larger ones. Sexual activity was

not observed. The presence of so many juveniles

in November may indicate that reproduction is

seasonal and occurs in late summer.

The largest specimen had a shell 9.5 mm long.

When placed in sea water, the valves parted

slightly and the narrow slug-like body appeared,

oriented so that the shell would be supported by

the branches of the algae. On the bottom, the

animal could support the weight of the shell in

an upright position for only a few seconds before

it would fall to one side. The animal moved with

an alternating motion between the front part and

the back part of the foot. The animals in the tank

tended to crawl up the sides to the surface where

they would form a cup with the bottom of the

foot and use surface tension to float upside dovm

with the heavy shell hanging down.

Most of the internal organs appeared to be in-

side the heavy shell and gave it a mottled green

color. The shell opened only about 1' 2 mm as the

small green body extended in front about 4 mm

and the tail showed only slightly behind. The

body was about 2 mm in height and less in

width. On the front of the head were two rolled,

yellow-tipped rhinophores which were about 2

mm in length. The forepart of the foot was slight-

ly extended and widened. Just above the exten-

sion of the foot was a flangelike lip. Behind the

rhinophores on top of the neck was a small tur-

retlike hump with two eye spots on the front. A

slight ridge extended from this hump along the

neck and into the shell. Under 20 magnifications,

the body was clear and gelatinous, with horizon-

tal rows of microscopic green nodules as inclu-

sions. There was a row of small white dots along

the margin of the foot and on the rhinophores.

When the animal withdrew, a sequence of

events took place. The foot folded downward

along a central line, the rounded cheeks folded

inward, the rhinophores came together vertically,

and the body disappeared into the shell which

then closed.

The shell was translucent yellow-green with

several clear rays extending from the umbones to

the margins. Two dark rays were on either side

of each umbone and extended laterally for about

1 mm. The tightly coiled nucleus of the em-

bryonic shell was attached to the umbone of the

left valve and extended horizontally across the

umbone of the right valve.

Phyllaplysia padina Williams & Gosliner, 1973

In March, 1975, a number of specimens of

Phyllaplysia padina Williams & Gosliner, 1973

were collected from Padina in tide pools at Cabo

Tepoca, Sonora. The animals were observed,

photographed, and preserved. Several shells were

extracted and photographed. Excellent drawings

of the animal have been published (Williams &

Gosliner, 1973a); but the living animal has not

been figured.

Numerous specimens have since been taken

from Padina intertidally in the Guaymas Area as

far north as Bah'a de Algodones. In May, 1975,

and again in May, 1976, large numbers of these

animals were observed at Bahi'a de Los Angeles,

Baja California Norte. On Isla Smith in this

region, there is a man-made turtle pond. When

the tide is out, water pours over a six foot dam

into a pool. There is some Padina in this pool. In

1975, six Phyllaplysia padina were taken from

here but there were no animals found in 1976. At

Punta la Gringa, across the channel on the

mainland, the species was abundant on the algae

from low water out to at least 10 meters. In May,

1976, high wind and rough water left large

amounts of Padina at the high tide line. The

algae was populated with this species. Twenty-

four hours later, the algae was drying in the hot

sun and wind. A few animals were still clinging

to it and revived completely when placed in fresh

sea water.

We did observe a previously unrecorded fact

concerning the coloring of the living animal.

When studied under 20 magnifications, the body

was uncolored and clear. The apparent greenish

brown color was due to inclusion in the tissue of

longitudinal rows of microscopic nodules. Several

photographs show this so clearly that individual

nodules can be distinguished. Individual animals

differed widely in the concentration of the

nodules.

The normal habitat and range for this species

seems to be wherever Padina will grow and from

the head of the Gulf of California at least as far

south as the Twenty-eight Parallel.

m THE NAUTILUS

April 25.1977

Vol. 91 (2)

ACKNOWLEDGMENTS

TVie p;uidance of Mr. Gale Sphon, Curatorial

Assistant, Natural History Museum of Los

Angeles County, in the preparation of the

manuscript is gratefully recognized. We also

thank Dr. James McLean, Curator of Invertebrate

Zoolog>', Natural History Museum of Los Angeles

County, who read the manuscript and made

helpful suggestions.

LITERATURE CITED

I>dll, W. H. 1918. Description of new species of shells, chiefly

from Magdalena Bay. Lower California. Pi-oc. Hiol. Soc

Wiish tnijtwL 31: .5-8 (Feb. 27).

Fisc-her. Paul. 18.57. Description d'especes nouvelles. Jour, de

Co/ic/if//. 5(2): 273-77 (.Jan.).

Keen, A. Myra. 1960. The riddle of the bivalved gastropod.

ne Velujer 3(1): 28-.30 (.July 1).

Keen, A. Myra. 1971. Sea sheik of tropical West Ameiica :

marine mollusks from I5aja California to Peru. Stanford

Univ. Press. Stanford. Calif, i-xiv-t-1066 pp.; ca. 4000 figs.,

22colorplts. (Sept. 1).

Keen. A. Myra and Allyn Smith. 1961. West American species

of the bivalved ga,stroix)d genus Berthelinia. Proc. Calif.

Acad. Sci. 30(2): 47-66; figs. 1-33; 1 pit. (March 2f)).

Larson, Mary and Hans Bertsch. 1974. Northward range ex-

tensions for Lobiger souverbii (Opisthobranchia:

Sacoglossa) in the Eastern Pacific. The Veliger 17(2): 225

(Oct. 1).

Pilsbry. H. A. and A. A. OLsson. 194.3. New marine mollu.sks

from the west coast. Ue Nautibu, 56: 78-81, pit. 8 (Feb. 15).

Smith, Allyn. 1961. Notes on the habitat of Berthelinia sp.

nov. from the vicinity of I^ Paz, Baja California, Mexico.

The Veliger 3(3): 81-82 (.Jan. 1).

Sphon. Gale. 1971. New opisthobranch records for the Eastern

Pacific. Tfie Veliger 13(4): .368-69 (Oct. 1).

Sphon. Gale and Hans Bertsch. 1974. Green Dragons. Terra

(Quarterly Mag. Nat. Hist. Mus. Ljs Angeles Co.. Calif.)

12(3): 21-29; color illustrated (Winter).

Sphon, Gale and David K. Mulliner. 1972. A preliminary list

of known opLsthobranch from the Galapagos Islands w^llected

by the Ameripagos expedition. The Veliger 15(2): 147-.52; 1

map (Oct. 1).

Williams. G. C. and T. M. Gosliner. 197.3a. A new species of

anaspidean optisthobranch from the Gulf of California. Ihe

VW(!/f;- 16(2): 216-.32 (April 1).

Williams, G. C. and T. M. Gosliner. 1973b. I^nge extensions

for sacoglossan opisthobranchs from the coasts of California

and the Gulf of California. The Veliger 16(1): 112-16; 2

maps (.July 1).

THE MIOCENE BIVALVE CUMINGIA MEDIALIS (SEMELIDAE)

FROM SOUTH CAROLINA

Clement L. Counts, III

Department of Biological Sciences

Marshall University

Huntington, West Virginia 25701

Previous reports of the Miocene bivalve Cum-

imjid DK'dialis Conrad, lS()(i have been almost en-

tirely limited to North Carolina, Maryland and

Virginia. Glenn (1904) reported C. mcdiali.^ from

the Miocene of Maryland and cited localities for

specimens taken from Virginia and North Caro-

lina. Shimer and Shrock (1944) also reported (\

nicdialis from the Choptank Formation of

Maryland and gave ranges of Maryland, Virginia,

North Carolina and South Carolina without

citing specific localities. Richards (1947) reported

a specimen taken from a well, 18.3 m from the

surface, dug at Edenton, Chowan County, North

Carolina. This specimen was placed in the collec-

tion of the Academy of Natural Sciences of

Philadelphia (ANSP 16773) where the holotype

and paratypes, from James River, Vii-ginia, also

reside (ANSP 18839). The present note reports

the second locality in South Carolina from which

C. mi'diulit< has been taken.

A right valve of C. medialift was found in

sea-wrack at the high tide line at Crescent

Beach, Horry County, South Carolina 18

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 67

August 1975. The shell was believed to be of re-

cent origin and was sent to Dr. R. Tucker Ab-

bott for confirmation. However, upon examina-

tion by Dr. Abbott at the Delaware Museum of

Natural History, it was properly identified as a

fossil or subfossil and accessioned DMNH

103141. It was suspected by Dr. Abbott that the

shell may have washed up from a fossil outcrop

offshore.

A specimen from the Peedee River, just south

of the new locality, was reported by Glenn

(1904). This specimen was the only such find of

C. medialis in South Carolina prior to the pre-

sent report.

Mr. Robert H. Schlutter (personal com-

munication) has noted that the specimens

reported by Glenn (1904) from Maryland are

most probably not from Maryland but from

Virginia. Thus, the possibility that C. medialis is

a Maryland form is doubtful and its citation as a

representative bivalve of Maryland dubious.

This was pointed out by Glenn (1904) but later

references to the species place it in Maryland

without noting this possibility.

The author wishes to thank Dr. R. Tucker

Abbott and Mr. Robert H. Schlutter for their ad-

vice and assistance.

LITERATURE CITED

Glenn. L. C. 1904. Mollusca (Pelecypoda). Maryland Geol.

Survey, Miocene. 274-401.

Richards, H. G. 1947. Invertebrate fossils from deep wells

along the Atlantic coastal plain. Jour. PaleontoL 21(1):

23-37.

Shimer. H. W., and R. R. Shrock. 1944. Index Fossils of

North AmeHca. MIT Press (Cambridge, Mass.). ix + &37

pp.

LATITUDE, HABITAT, AND HATCHING TYPE FOR

MURICACEAN GASTROPODS

Tom M. Spight

Woodward-Clyde Consultants

3 Embarcadero Center, Suite 700

San Francisco, California 94111

ABSTRACT

Among rocky shore and oyster-reef muricaceans. all high latitude species

hatch as young stiails, while all tropical species hatch as veiigers. In contrast,

species from other habitats at all latitudes generally hatch metamorphosed

Among prosobmnchs in general, more species of both hatching types are fonnd

at low latitudes than at high latitudes and, m Europe, on continental suites

rather than on islands.

INTRODUCTION

One of the most intriguing generalizations of

prosobranch ecology is that in some places most

species hatch as planktonic larvae, while in other

places most species hatch as fully formed snails.

The predominant hatching type varies both with

latitude and with habitat. Typically many species

have planktonic larvae at tropical sites and in

shallow waters, while in the deep sea or in the

arctic, most hatch metamorphosed (Thorson,

1950). These generalizations raise two questions:

(1) are species that hatch metamorphosed in cold

water areas replaced by ecological equivalents

with planktonic larvae in warm-water areas; and

(2) is one hatching type replaced more completely

in some habitat types than others?

68 THE NAUTILUS

April 25,1977

Vol. 91 (2)

The latitudinal change in prevailing hatching

ty'pe does not require species replacements. The

change parallels a large change in community

diversity. As long as most species added along the

latitudinal gradient have swimming larvae, the

prevailing hatching type will change, whether

species with metamorphosing larvae are replaced

or are about equally numerous everywhere. In

the data presented by Thorson (1965) for Euro-

pean prosobranchs, about equally many species

with metamorphosed hatchlings are found at all

latitudes, while the diversity of species with

swimming larvae rises abruptly between 30°N

and eO^N (Fig. 1). Thorson's data (Fig. 1) include

50-60% of the total fauna and therefore

200

150

o

0.

tn

o 100 -

a:

ui

B

50 60

LATITUDE CN)

FIG. 1. Pint of estimated number af ftpecies of prnnohrnnrh

snaik hatching metnmorphoaed (triangles) and hatching as

.•fwimming larvae (circles) for various European localities as a

functon of latitude. Each paint is obtained by midtiplying the

estimated total number of prosobranchs for the site by the

fraction of species for each hatching type, as based on a sam-

ple of iO-60% of known hatching lifpes. Data fnmi Thorson

(19U and 1965). Solid figures and solid lines, mainland sites:

open figures and dotted or dashed lines, island sites. The lines

are fitted by linear regression and have the follouing r'

valties: metamorphosed, mainland O.Oi, island 0.01; smmming

larvae, mainland 0.81, island 0.87.

estimates of faunal composition based on these

are both relatively unbiased and comparable to

each other. Within the 40-70" latitudinal range,

and among prosobranchs as a whole, species

hatching metamorphosed are supplemented

rather than replaced by species with plantonic

larvae. Figure 1 also demonstrates an additional

habitat variable: isolation. At all latitudes, island

sites have fewer species of both hatching types.

Frequencies of the larval types also vary from

one habitat to another. Most tropical .shore

species have planktonic larvae (91% o( 21 species,

Lewis, 1960; 100% of 13 species, Ostergaard,

1950), while in deeper waters (here "deep" refers

to waters in the range of lO-l(X) m) many species

hatch metamorphosed (25%, Thorson, 1940a: 69%,

Knudsen, 1950). Hatching types were obtained for

relatively few species in these studies, and the

selection undoubtedly reflects the particular tax-

onomic groups these authors chose or were able

to study. To confirm the habitat-larval type rela-

tionships, further data are required.

Larval types of many species have been

reported incidentally, and these can be used to

confirm the pattern of changes observed in the

regional faunal studies. With this in mind. I have

reviewed the published data on members of one

major group, the superfamily Muricacea

(including the thaidids).

METHODS

The available habitat descriptions (obtained

from the papers cited or from standard works)

fall into 4 major categories: intertidal rocky

shores, oyster reefs, shallow-water sand bottoms,

and deeper waters (10-100 m, as opposed to the

deep sea). Thais cornnata, found on mangroves,

fits into none of these categories, and is arbitrari-

ly included with the oyster reef species. The

oyster reef species appear to be found on more

kinds of substrates than the other species are; in-

dividuals of most of these species can be found

feeding on clams on muddy bottoms or barnacles

on rocky shores as well as on oysters.

Larval types are summarized by wide lati-

tudinal bands (Table 1). Latitudinal bands were

chosen to approximate equatorial, tropical, sub-

tropical, temperate, and boreal areas. Too few

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 69

TABLE 1. Percentage of species 0/ Muricaceans hatching as

long-term veligers (more than 1 week) as a function of

lot it tide and habitat. Number of species in parentheses.

data are available to identify local patterns, and

therefore no attempt was made to accommodate

more subtle features of species distributions.

The latitudinal band for each species was ob-

tained from the site at which observations were

made rather than from the species range. Single

sites were used to avoid the bias of including

wide-ranging species in more than 1 band. How-

ever, of 6 species studied by more than one

author, 3 were studied in different latitudinal

bands (Cuma turbinoides = Thais carinifera?,

Occnebra japonwa = Tritonalia japonica, and

Thais floridana = Thais haemastoma floridana)

and are entered twice in Table 1. Three species

were studied by two authors within the same

latitudinal band: Thais fasciata (T. rustica).

Acanthina lapilloides (A. spirata), Favartia

ceUulnsus. These 3 species are entered only once

in Table 1.

HATCHING TYPES IN THE MURICACEA

Each species is listed as given by the original

author, together with the approximate latitude of

the original author's observations.

Intertidal Rocky Shores

Hatch as veligers: Thais bufo (Lamarck) 8''N

(Natarajan 1957), Thais tissoti (Petit) S^N

(Natarajan 1957), Vitularia salebrosa (King and

Broderip. 1832) 9''N (D'Asaro 1970b), Thais

tieltoidea Lamarck LTN (Lewis 1960), Thais

flofidana Conrad 13°N (Lewds 1960), Thais patula

Linnaeus 13°N (Lewis 1960), Cuma turbinoides

Blv. 22°S (Risbec 1935), Thais rustica Lamarck

25°N (D'Asaro 1970a), Thais carinifera (Lam.)

27°N (Thorson 1940a), Jopas francolinuyn

Bruguiere 27''N (Gohar and Eisawy 1967), Thais

hippocastaneum (Lam.) 27"N (Thorson 1940a),

Dicathais aegrota (Reeve 1846) 32"S (Phillips

1969), Thais fasciata Rve. 32»N (Lebour 1945),

Ocejiebrapoulsoni Carpenter 33°N (Fotheringham

1971), Shasktrus festivus (Hinds) 33°N (Fother-

ingham 1971), Morula marginalba (Blainville)

33°S (Anderson 1967), Bedevina birileffl (Lischke)

33°N (Amio 1957), Concholepas conchoiepas

(Bruguiere) 39°S (Gallardo 1973).

Hatch as snails: Favartia cellulosu^ (Conrad)

25<'N (Raeihle 1966), Favartia nuceus (Morch)

32°N (Lebour 1945), Thais dubia 34''S (Bokenham

and Neugebauer 1938), Bedeva hanleyi (Angas)

35''S (Anderson 1967), Acanthina lajnlloides 36°N

(Hewatt 1934), Acanthina spirata (Blainville),

37''N (personal observations), Nucella calcar 39°S

(Gallardo, 1973), Ocenebra lumaria Yokoyama

41°N (Luckens 1970), Ocinebra aciculata Lamarck

43''N (Franc 1940), Ceratostoma foliatum

(Gmelin) 48»N (Spight et al. 1974), Thais

canaliculata (Duclos) 48°N (original), Thais

emarginata (Deshayes) 48°N (original), Thais

lamellosa (Gmelin) 48°N (original), Nucella

lapfillus (Linnaeus) 54''N (Pelseneer 1910), Thais

lima (Gmelin) 51°N (original).

Oyster Reefs

Hatch as veligers: Thais coronata Lam. 6°^

(Knudsen 1950), Thais haemastoma floridana

(Conrad) 26"N (D'Asaro 1966), Purpura clavigera

Kuster 37°N (Amio 1963), Purpura bronni

Dunker41''N (Amio 1963).

Hatch as snails: Eupleura caudata (Say) 37°N

(MacKenzie 1961), Ocenebra japonica (Dunker)

43°N (Amio 1963), Ocenebra japonica 47''N (Chap-

man and Banner 1949), Ocenebra erinacea (L.)

52°N (Hancock 1960), Urosalpinx cinerea (Say)

52°N (Hancock 1959).

Shallow-water Sand Bottoms

Hatch as veligers: Chicoreus brunneus Link

22°S (Risbec 1932), Hexaplex kosterianus Tapp.

27''N (Thorson 1940a), Leptoconchus cumingii

(Deshayes) 27''N (Gohar and Soliman 1963),

Rapana thomasiana Crosse 37''N (Hirase 1928).

Hatch as veliconchas and/or snails: Murex

trapa Roding 8°N (Natarajan 19,57), Chicoreus

mrgineus var. ponderosa Sowerby S^N (Natarajan

1957), Chicoreus incamatus (Roding) 27°N (Gohar

70 THE NAUTILUS

April 25,1977

Vol. 91 (2)

and EisawT 1967), Chicoreus ramomts (Linne)

27»N (Gohar and Eisawy 1967).

Hatch as snails: Chicoreus torrefactus (Sower-

by) 18'S (Cernohorsky 1965), Ton'amnrex fem/».s

(Reeve) 22°S (Murray and Goldsmith 1963),

Chicoreus florifer Reeve 26°N (D'Asaro 1970),

Chicoreus pomum Gmelin 26°N (D'Asaro 1970a),

Calotrophon ostrearum (Conrad) 30°N (Radwin

and Chamberlin 1973), Urosalpinx perrugata

(Conrad) 30°N (Radwin and Chamberlin 1973),

Hexaplex trunculu,'< (Linne) 43°N (Fioroni 1966).

Deeper Waters

Hatch as veligers: Hexaplex fvlvescens (Sow)

28°N (Moore 1961). Rapana bidbosa Sol. 28»N

(Thorson 1940a).

Hatch as snails: Chioreits quadrifrons (Lam.)

5°N (Knudsen 1950), Chicoreus senegalensw

(Gmel.) 5°N (Knudsen 1950), Murex fasciatus

Tryon 1880 10°N (Knudsen 1950), Muricopsis

blaimnllei (Payraudeau) 41''N (Fioroni 1966 after

Franc 1948), Murex brandaris Linne 43°N

(Fioroni 1966), Ocenebra spec. 43°N (Fioroni

1966), Trophon muricntus (Montagu) SO^N

(Labour 1936), T)vphon truncahis (Str6m) 57''N

(TTiorson 1946), Trophon clathratus (L.) var. Gun-

neri Loven 65<'N (Thorson 1940b).

CONCLUSIONS

The predominant type of hatching changes

more markedly among rocky shore murica

ceans than it does among prosobranchs as a

whole (Fig. 1). In this habitat, all high-latitude

species metamorphose before hatching, and all

tropical species have planktonic larvae. The rock>'

shore fauna is relatively well known, because it is

accessible at all latitudes; therefore further work

is unlikely to change this generalization. Species

of one hatching type are completely replaced by

ecological equivalents of the other along the

latitudinal gradient. The two hatching types are

mixed between 25-30° (Table 1), and studies at

these latitudes should reveal the relative ad-

vantages of the two hatching types, and possible

instances of competition between them. A

parallel latitudinal trend is observed among

oyster reef species.

Hatching types for shallow-water sand species

and deep-water (10-100 m) species do not change

in the same manner. Species with metamorphosed

hatchlings prevail at most latitudes in both of

these habitats. In the shallow-water sand habitat,

one also finds an intermediate hatching type, a

non-feeding Veliconcha that metamorphoses a

few days after hatching.

Considering all habitats, diversities of both

hatching types are probably greatest at low lat-

titudes. According to available data, the

latitudinal gradient in hatching type is striking

(Milekovsk>', 1971) and might imply a low

number of tropical species that hatch metamor-

phosed. However, a disproportionately large

number of the tropical observations are on rocky

shore species. Species from other near-shore

habitats are likely to have metamorphosed hat-

chlings at all latitudes. When these are included,

species with metamorphosed hatchlings will pro-

bably be shovra to be most diverse at lower

latitudes. In the only whole-fauna available to

date (Fig. 1), species with metamorphosed hatch-

lings are more diverse at the lowest latitude

(Portugal, 41°N) than at the highest.

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Amio, M. 1957. Studies on the eggs and larvae of marine

gastropods. Part I../ Shunonosek-i Coll. Fisk 7: 107-116.

Amio. M. 1963. A comparative embryology of marine

gastropods, with ecological emphasis. J. Shinwnoseld ColL

F-ish. 12: 229-.'353.

Anderson, D. T. 1967. Further observations on the life

histories of littoral gastropods in New South Wales. Proc.

Linnean Sue. New South Walea 90: 242-251.

Bokenham. N. A. H. and F. L. M. Neugebauer. 1938. The ver-

tical distribution of certain intertidal marine gastropods in

False Bay. with notes on the development of two of them.

.4«H.A'(i/(!/.A/i«. 9:113-137.

Cemohorsky. W. 0. 1965. The radula. egg capsules, and young

of Murex (Chicoreus) torrefactus Sowerby. Veliger 8:

231-233.

Chapman, W. M. and A. H. Banner. 1949. Contributions to the

life history of the .Japanese oyster drill (Tritonnlia japnnica)

with notes on the other enemies of the OI>Tnpic Oyster

((htrea lurida). Wiishinytim Dept. Fixh. Biol, kept 49A:

167-2tK),

U'Asaro. C. N. 1966. The egg capsules, embryogenesis. and ear-

ly organogenesis of a common oyster predator, Thais

haemastoma floridana (Gastropoda Prosobranchia) Bull

Mar. Sci 16: 884-914.

D'Asaro. C. N. 1970a. Egg capsules of prosobranch molluscs

from South Florida and the Bahamas and notes on spawn-

ing in the laboratory. Bull. Mar. Sci. 20: 414-440.

Vol. 91 (2

April 25. 1977

THE NAUTILUS 71

D'Asaro. C. N. 1970b. Egg capsules of some prosobranchs from

the Pacific Coast of Panama. Veliger 13: 37-43.

Fioroni. P. 1966. Zur morphologie und embryogenese des

Darmtraktes und der transitorischen Organe bei Prosobran-

chiern (Mollusca, Gastropoda). Renie Suisse de ZooUxjie 73:

621-876.

Fotheringham. N. 1971. Life history patterns of the littoral

gastropods Shaskyus feMiinis (Hinds) and Ck-enebm /Wwwi

Carpenter (Prosobranchia: Muricidae).&()%i/52: 742-757.

Franc. A. 1940 Recherches sur le developpement D'Ocinehra

aacidata, Lamarck (Mollusque gasteropode). Bull. Biol. FV.

Belg. 74: 327-345.

Gallardo, C. 1973. Desarrollo intracapsular de Concholepas

corwholejxis (Bruguiere) (Gastropoda Muricidae). Museo Nn-

Clonal de Historia Nntuml Santiago de Chile Publ. Oca.'!. 16:

1-16.

Gohar, H. A. F. and A. M. Eisaw>'. 1967. The egg-masses and

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Gohar. H. A. F. and G. N. Soliman. 1963. On the biology of

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Hancock, D. A. 19.59. The biology and control of the American

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Hancock. D. A. 1960. The ecology of the molluscan enemies of

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Hewatt, W. G. 1934. Ecological studies on selected marine m-

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Hirase, S. 1928. Eiablage von Rapana thomasiana Crosse.Ar-

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Knudsen, J. 1950. Egg capsules and development of some

marine prosobranchs from tropical West Africa. Atlantide

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Lebour, M. V. 1936. Notes on the eggs and larvae of some

Pl\-mouth prosobranchs. J. Mar. Biol. Assn. U. K. 20:

547-565.

Lebour, M. V. 1945. The eggs and larvae of some prosobranchs

from Bermuda. Proc. Zool. Soc. London 114: 462-489.

Lew-is, J. B. 1960. The fauna of the rocky shores of Barbados,

W. I Canadian J. Zool. 38: 391-435.

Luckens, P. A. 1970. Variation of shell characters of a species

of Ocenebra (Mollusca; Gastropoda) at Asamushi. Sci. Rept.

TShoku Univ. (Ser. IV, Biol.) 35: 149-1.59.

MacKenzie, C. L. Jr. 1961. Growth and reproduction of the

oyster drill Eupleura caudata in the York River. Virginia.

£co/o5fr/ 42: 317-338.

Mileikovsky. S. A. 1971. Types of larval development in

marine bottom invertebrates, their distribution and

ecological significance: a re-evaluation. Afar. Biol. 10:

193-213.

Moore, D. R. 1961. The marine and brackish water mollusca of

the State of Mississippi, ft/7/fle.s. Repts. 1(1): 24-27.

Murray, F. V. and M. H. Goldsmith. 1963. Some observations

on the egg capsules and embryos of Torvamurez territus

(Reeve, 1845). ./. Malacol. Soc Australia 7: 21-25.

Natarajan, A. V. 1957. Studies on the egg masses and larval

development of some prosobranchs from the Gulf of Mannar

and the Palk Bay. Proc. Indian Acad. Sci. 46(3): 170-228.

Ostergaard, .]. M. 1950. Spawning and development of some

Hawaiian marine gastropods. Pacific Science 4: 75-115.

Pelseneer, P. 1910. Recherches sur L'Embryologie des

Gastropodes. Mem. Acad. Royale Belgique Ser. 2 Vol. 3 pp.

1-167.

Phillips, B. F. 1969. The population ecology of the whelk

LHcathais aegrota in Western Australia. Aust. J. Mar.

FVeshiv. Re.^. 20: 225-265.

Radwin, G. E. and J. L. Chamberlin. Patterns of larval

development in stenoglossan gastropods. TYans. San Diego

Soc Nat. Hist. 17: 107-118.

Raeihle, D. 1966. An observation of captive Murex cellulosus

Conrad. yl?in, Rept. A mer. Malacol. Unirni 1966: 28.

Risbec, J. 1932. Notes sur la ponte et le developpement de

mollusques gasteropodes de Nouvelle-caledonie. Bull. Soc.

Zool. France 57: 358-375.

Risbec, J. 193.5. Biologie et ponte de Mollusques Gasterpodes

neo-calendoniens. Bull. Soc. Zool. FVance 60: 387-417.

Spight, T. M., C. Birkeland and A. Lyons. 1974. Life

histories of large and small murexes (Prosobranchia:

Muricidae). Afar. Biol. 24: 229-242.

Thorson, G. 1940a. Studies on the egg masses and larval

development of Gastropoda from the Iranian Gulf. Dan. Sci.

Invest. Iran 2: 159-238.

Thorson, G. 1940b. Notes on the egg-capsules of some North-

Atlantic prosobranchs of the genus Troschelia.

Chrysodomiis, Voluiopsis. Sipho and Trophon. Vidensk.

Medd.fra Dansk naturh. Foren. 104: 251-265.

TTiorson, G. 1944. Marine Gastropoda Prosobranchiata (The

zoology of Iceland IV). Medd. om Gronland 121:1-181.

Thorson. G. 19.50. Fteproductive and larval ecolog>' of marine

bottom inveriebrates. Biol. Rev. 25: 1-45.

Thorson. G. 196.5. The distribution of benthic marine mollusca

along the N.E. Atlantic shelf from Gibraltar to Murmansk.

Proc. First Eiirop. Malar. Congr. (1962) pp. 5-25.

Thorson, G. 1946. Reproduction and larval development of

Danish marine bottom invertebrates. Medd. Komm. Danm.

Fisk. -og Havunders.. ser Plankton. 4: 1-523.

72 THE NAUTILUS

April 25,1977

Vol. 91

CONUS VIOLA, A NEW NAME FOR C. VIOLACEUS REEVE

Walter 0. Cernohorsky

Auckland Institute and Museum

Private Bag, Auckland, New Zealand

ABSTRACT

The new subfititute name Conus viola is here proposed fur the hoinouymous

C. violaceus Reeve, from the tropical West Pacific region.

Conus viola Cernohorsky, new name

Figs. 1 - 3

1844. Co«M.s violaceus Reeve, Conchologia Iconica,

vol. 1, pi. 44, fig. 241; 1858 Sowerby, Thesaurus

Conchyliorum, vol. 3, p. 45, pi. 208, fig. 537;

1875 Weinkauff, Martini & Chemnitz Syst.

Conchyl. Cabinet, ed. 2, vol. 4, pt. 2, p. 76, pi.

46, fig. 11; 1937 Tomlin, Proc. Malac. Soc. Lon-

don, vol. 22, p. 328 (erroneously synonymized

with C luteus Sowerby^ [non C. violaceus

Gmelin, 1791]

1884. Conus violaceus Reeve [pars], Tryon,

Manual of Conchology, vol. 6, p. 88, pi. 28, fig.

82 (only)

1964. Conus luteus var. Sowerby, Marsh & Rip-

pingale. Cone shells of the world, p. 124, pi. 18,

fig. 7 {non Sowerby, 1833)

1972. Cvnus species Hinton, Shells of New Guinea

and the central Indo-Pacific, p. 82, pi. 40, fig. 6.

1975. Conus molaceus. C. tendineus or Conus sp.?

Leehman, Hawaiian Shell News, vol. 23, No. 6,

p. 6, text figs.

Type locality: Matnog, Island of Luzon, Philif)-

pines.

Type specimens: TTie three syntypes of C.

molaceus Reeve, accompanied by a label which

bears Tomlin's remark = luteus Broderip, are in

the British Museum (Nat. Hist.), London. The

specimen measuring 41.0 mm in length and 15.0

mm in width, is here selected as the lectotype of

C. violaceus ( = C. viola new name).

Conus violaceus was first described in

literature by Reeve (1844), who based his

FIGS. 1-2. h'ctdtyi)!' (i/ ('onus violaceus Rerve (= C. viola

Cernohorsky, new name: B.M.N.H.. length 1,1.0mm. uMlh 15.0

mm. 3. Specimen o.f C. viola from Bathurst Id., Nth.

Australia: Icni/th ■'io.S mm. u-idth .Hi mm. 4-5, Topotype of

C. luteus Sowerby, from Anaa Id.. Tiiamotus; B.M.N.H.,

length SS.Omm.

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 73

diagnosis on three specimens from the Cuming

collection. Reeve's C. violaceus, however, is a

primary homonym of C. vwlacem Gmelin, 1791,

which is an earlier name for the Indian Ocean

species C. tendineus Hwass in Bruguiere, 1792.

Tomlin (1937) did not propose a replacement

name for the homonymous C. violaceus Reeve, as

he considered this species to be synonymous with

C. luteus Sowerby, 1833.

C. viola and C. luteus are similar but quite

distinct species, with C. viola known only from

an area between the Philippines and North

Australia, whereas C. luteus is widely distributed

throughout the tropical Pacific. The average size

of C. viola is about 50 mm, the shell is cylin-

drical, the first 2-3 post-embryonic whorls are

finely nodulose, the penultimate whorl is inflated

and telescopic in appearance, sutures are firmly

but irr^ularly adpressed, the outline of the body

whorl is cylindrical with the first two-thirds of

the body whorl descending almost vertically

before tapering towards the base, the aperture is

narrow at the start but slightly flaring basally,

and the sculpture consists of 6-10 spiral threads

on the spire whorls, obsolete spiral threads on the

body whorl and up to a dozen close-set cords at

the base. Fresh specimens are pale violet and or-

namented with brown spots on the spire whorls,

three broad but often dilacerated brovra bands on

the body whorl which are usually interrupted in

the centre of the whorl by a pale band, and spiral

rows of small brown spots, aperture pale violet.

C. luteus is considerably smaller, averaging

about 30 mm in length, the spire is short and

convex, whorls are not inflated but tight, the 2-3

post-embryonic whorls are smooth, the sutures

are narrowly canaliculate, the shoulder is

moderately broad, smooth and sloping and the

body whorl tapers rapidly toward the slender

base; shell glossy, obsoletely spirally striate on

the body whorl, the arcuate axial striae on the

spire whorls are crisper and spiral threads fewer

and the aperture is uniformly narrow and does

not flare basally. The colour is yellow, orange,

pink or rose-red, the centre of the body whorl has

a narrow white band or blotches which are

bordered by quadrate, irregular and distinctly

smudged dark brown spots, and spiral rows of

dark brown interrupted lines are present in some

individuals.

Dark coloured specimens of C. viola have been

illustrated by Leehman (1975) and the banded

form by Hinton (1972). The lectotype of C viola is

a form where the brown bands are dilacerated in-

to longitudinal zones.

LITERATURE CITED

Hinton, A. 1972. Shells of New Guinea and the Central Indo-

Pacific. R. Brown & Associates Pty. Ltd., Port Moresby, and

Jacaranda Press, Milton, 94 pp., 44 col. pis.

Leehman, E. G. 1975. Conus confusion. Hawaiian Shell News.

23(6): 6, text figs.

Reeve, L, 1843-44. Conchologia Iconica; monograph of the

genua Qmits. L. Reeve, London, vol. 1. 47 pis.

Tomlin. J. R. le B. 19.37. Catalogue of Recent and Fossil Cones.

Proc. Malae. Soc. London, 22: 205-330.

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74 THE NALITILUS

April 25,1977

Vol. 91 (2)

IS THAIS CAN ALICULATA (GASTROPODA: MURICIDAE)

EVOLVING NURSE EGGS?

Tom M. Spight

Woodward-Clyde Consultants

3 Embarcadero Center, Suite 7()0

San Francisco, Calif. 94111

ABSTRACT

Thais canaliculata appears to be in the course of evolving from one

reproductive mode (!()()% fertility) to another fprovmon of nurse eggs for em-

bryos). In some populatiori% all eggs are fertile. In other populations, as few as

16% in each capsule may he fertile and the infertile eggs are used as nurse

eggs by the embryos. If T. canaliculata is to complete the transition to nurse-

egg feeding, two major adaptive problems must be solved: fertility must be

regulated, arui new larger hatchlings must become much more likely to survive

to maturity.

Some Thais canaliculata (Duclos, 1832)

females produce infertile eggs, and these are used

by the embryos as nurse eggs, while other

females produce only fertile eggs (Lyons and

Spight 1973). These variations in reproductive

mode may indicate that T. canaliculata is in the

process of abandoning one mode in favor of

another. This paper will examine available data

on fertility in order to evaluate this hypothesis.

METHODS

Egg capsules were collected at Cattle Point and

South Beach (on the southeast tip of San Juan

Island, Washington) during May, 1970, at Cattle

Point during May, 1972, and near Friday Harbor

during May and August, 1972. One of the Friday

Harlx)r clusters was attended by a 44-mm female,

and one by a 31-mm female. Capsules were

opened shortly after collection, and contents (eggs

and/or embryos) were counted. The 41-mm

female continued to deposit capsules while kept

in a laboratory aquarium. Some of these capsules

were kept to obtain embryo counts.

RESULTS

Capsules from Cattle Point and South Beach do

not contain infertile eggs. The capsules collected

during 1970 contained cleaving eggs or early em-

bryos, and all eggs were developing. The average

1970 capsule was 8.23 mm long (N = 23, SD =

0..53) and contained 28.1 embn,'os (SD = 8.35).

The 1972 capsules, which contained embryos near-

ly ready to hatch, were slightly smaller (8.04 mm,

N = 17, SD = 0.72), and contained W/o fewer

embryos (23.5, SD = 4.39). Therefore, embryo

numbers do not decline significantly during

development (Fig. 1, open vs. solid circles).

Capsules from Friday Harbor do contain infer-

tile eggs. Several capsules from the 44-mm female

were opened, and of these, 8 contained embryos

that had almost reached the feeding stage. From

16% to 92% of the eggs in these capsules were

developing (mean, 56%). I found feeding embryos,

nurse eggs, and debris of broken nurse eggs in

each of the capsules deposited by another female.

Only 35% of the intact eggs were developing. Ac-

tual fertility must have been even lower, since

some of the nurse eggs had already been torn

apart and consumed.

The number of eggs per capsule is significantly

correlated with capsule size (capsule length, ex-

cluding the stem; Fig. 1). When all counts from

Cattle Point and South Beach capsules, and

counts of eggs plus embryos from Friday Harbor

capsules are included, the logarithm of capsule

height (X) accounts for 34% of the variation in

the logarithm of egg count (Y), and the following

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 75

linear regression between these variables is ob-

tained:

Y = 1.7299 X - 0.1527

for a total of 55 capsules (F , „ = 27.0891, P <

0.01). Almost all of the embryo counts for the

Friday Harbor capsules fall well below this com-

mon line (solid triangles, Fig. 1).

10

o

tr.

m

2

UJ

[£

O

<n

<s

o

2

7 8 9 10 II 12

CAPSULE LENGTH (mm)

FIG. L Contents of capsules of Thais canaliculata from

San Juan Island. WashingUm. Circles indicate capsules from

Cattle Point and South Beach. Open circles and the dotted

line indicate early embryos, while solid circles and the da.'iheil

line indicate late embryos. Triangles indicate capsides from

Friday Harbor. Open triangles and the thin solid line repre-

sent eggs, while .tolid triangles represent embryos. The heavy

line is the calcidated regression fw all data (except .solid

triangles). Individual capsides from Friday Harbor are

represented by 2 triangles (one empty, one filled) when both

egg and embryo counts were obtained. All lines are fit by

least-squares linear regression.

DISCUSSION

Fertility of Viais canaliculata eggs varies

strikingly around San Juan Island, Washington.

In some populations, virtually all eggs become

hatchlings. Counts of early and late embryos dif-

fer by only 16% at South Beach and Cattle Point.

Larger developmental mortalities have been

reported for most other muricid species without

nurse eggs (14-58%; Cole 1942, Federighi 1931,

Hancock 1959, Phillips 1969). In other popula-

tions, many eggs are infertile, and these are used

as nurse eggs by the embryos. The T. cana-

liculata populations of Fig. 1 may be at different

stages of the process of changing from one

reproductive mode (100% fertility) to another

(provision of nurse eggs).

If reproductive mode is changing, what is the

direction of the change? T. canaliculata embryos

possess a feeding mechanism unlike any other

that has been described (Lyons and Spight, 1973).

Firstly, this mechanism could have been in-

herited, but if so, the ancestor has no mid-

latitude species that produce nurse eggs among

its descendents. Secondly, T. canaliculata may

have evolved a low-fertility reproductive mode

early in its history and is now abandoning this

mode. A third explanation is most simple because

it postulates the fewest evolutionary changes:

some T. canaliculata populations are utilizing

nurse eggs for the first time.

If the reproductive mode is changing, how far

has the change progressed? The fertility data pro-

vide a kind of measure of progress because as fer-

tility varies from capsule to capsule, hatching

size also varies, and females whose fertility is

variable will in the long run be less fit than those

with constant fertility and offspring of the op-

timum size. If large hatchlings are much more

likely to survive through the post-hatching period

than small ones are, then females that produce

small hatchlings will be at a disadvantage; if not,

females that produce small hatchlings will be the

most fit because they produce more offspring.

Among the Friday Harbor capsules, some con-

tained only a few embryos (which would become

large hatchlings), while nearly all of the eggs in

others were fertile. Fertility varies much more

than it does among Acanthina spirata capsules.

76 THE NAUTILUS

April 25,1977

Vol. 91 (2)

although A. spirata has about the same average

fertility (Spight, 1976). Fertility is unregulated in

Friday Harbor populations, but selection favoring

regulation should be strong and therefore

reproductive characteristics should be changing

rapidly at the present time.

Each infertile egg reduces its parents' fecundi-

ty. Since only 35-56% of the eggs are fertile,

Friday Harbor females are producing less than

half as many embryos as females from Cattle

Point are (compare the filled triangles of Fig. 1

with other symbols). If the number of surviving

offspring per f)arent is to be similar at the two

sites, then each Friday Harbor offepring must

have a greater chance of surviving. Larger hatch-

lings are generally more likely to survive through

the post-hatching period than small ones are

(Spight 1972). T. canaliculntn eggs range from

590 to 650 ^m and eggs from Cattle Point become

hatchlings of 1150 to 1300 jim. When only 56% of

the eggs are fertile, the average embryo will have

nearly twice as much yolk as would an embryo

without nurse eggs, and therefore Friday Harbor

hatchlings should weigh twace as much as those

from Cattle Point. The large Friday Harbor

hatchlings should be more likely to survive than

the small ones from Cattle Point. However, if

survival is dependent on size alone, then the op-

timum hatching size is the same for all parents

of T. caudlicidatcu and an increase in hatching

size will result in a net decrease in the number

of hatchlings surviving through the critical post-

hatching period (Smith & Fretwell, 1974). If

nurse-egg feeding, accompanied as it is by

decreased fecundity, is to be evolutionarily suc-

cessful, then the optimum hatching size must be

altered. Further work will be required to deter-

mine whether necessary changes are in progress

for T. canaliculata.

LITERATURE CITED

Cole, H. A. 1942. The American Whelk Tingle. Urasalpiiijc

cinerea. on British oyster beds. Jour. Mar. Biol. Assn. 25:

477-508.

f'ederighi. H. 1931. Studies on the oyster drill, i'msalpinx

riiicrm. Ridl. U. S. Bureau Pi.sh. 47: 8.5-11.5 (19.31).

Hancock. I). A. 19.59. The biology and control of the American

Whelk Tingle, Urosalpini cinerea. on Eiiglish oyster beds.

Fishery Ini'esl. Lond. 22(2): 1-66.

Lyons, A. and T. M. Spight. 1973. Diversity of feeding

mechanisms among embryos of Pacific Northwest TTiots.

Veiiger 16: 189-194.

Phillips. B. F. 1969. The population ecology of the whelk

Dicathais aegrota in Western Australia. Australian Jour.

Mar Fi-e.^hu: Res. 20: 225-265.

Smith. C. ('. and S. D. Fretwell. 1974. The optimal balance

between size and number of offspring. Amer. Natur. 108:

499-.506.

Spight, T. M. 1972. Patterns of change in adjacent populations

of an intertidal snail, Thais lamellosa. Ph. D. Thesis,

University of Washington.

Spight. T. M. 1976. Hatching size and the distribution of

nurse eggs among prosobranch embroys. Biol. Bull. 150:

491-499.

THE CHINESE APPLE SNAIL, CIPANGOPALUDINA CHINENSIS,

ON ORCAS ISLAND, WASHINGTON'

Branley A. Branson

Eastern Kentucky University

Richmond, Kentucky 40475

ABSTRACT

A vprij hiiyr iiiipiildtidn o/ Cipangopaludina chinensis ((iraii. IS.SJ,) « irpiirlcil

fnini IjiL-c (abrade an (hra.s hliiiiil in tlic I'lKp't Smnid r('(jli>ii nf /r( stern

WiiiilniKjItiti.

Various authors have reported the estab- viviparid snail, Cipangopoludina chinen.'^!^ (Gray,

lishments of populations of the freshwater 1834), in widely separated sections of North

■ Part of a larger study supported by Sigma-Xi-Resa and In- America, assigning several specific epithets to the

stitutional grants. snails (Dundee, 1974), including Viviparus

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 77

malleatun Reeve and V. stelmaphoru^

Bourguignat. Previous reports of the species from

the state of Washington are restricted to a

population in Green Lake at Seattle (Hanna,

1966).

The population reported here was thriving in

1973 in Lake Cascade at Moran State Park on

Orcas Island, the largest and most highly tourist-

oriented body of land in the San Juan Island off

the Washington coast. Although I made no at-

tempt at estimating population size, 56 in-

dividuals were secured in approximately 30

minutes from an area no larger than two square

meters. The smallest individual is 7.0 mm in total

length, and the largest 44.0 mm, indicating, of

course, that reproduction was occurring at that

time. One shell and operculum were deposited at

the Delaware Museum of Natural History (no.

106584) as a voucher specimen.

LITERATURE CITED

Dundee, D. S. 1974. Catalog of introduced mollusks of eastern

North America (north of Mexico). Sterkiana 55: 1-37.

Hanna. G. D. 1966. Introduced mollusks of western North

America. Occ. Pap. Calif. Acad. Set. 48: 1-108.

THE POLYGYRID GENUS McLEANIA IN HISPANIOLA

Fred G. Thompson

Florida State Museum

University of Florida

Gainesville, Florida 32611

Mcleania is a genus of medium-sized depressed

helicoid land snails in which the species are

characterized by having a series of nodelike ser-

rations along the peripheral keel of the shell. Un-

til now the genus was thought to be monotypic

and endemic to Puerto Rico (see van der Schalie,

1948:70) where the type species, M. darlingtnni

Bequaert and Clench was discovered by Philip J.

Darlington, Jr. in 1938. Bequaert and Clench

(1939:283-284) tentatively placed Mcleania in the

Cepolidae (= Xanthonichidae, see Baker, 1956)

because of resemblances in size and shell shape

to some Hemitrochus. Baker (1940: 55-57)

demonstrated that the reproductive anatomy of

Mcleania is similar to that of Thysanopkom. Cur-

rently Mcleania, Thysanophora, and allied genera

are placed in the Thysanophorinae, a subfamily

ofthePolygyridae.

During June, 1974, and January, 1976, I col-

lected shells of two undescribed land snails from

the Barahona Peninsula, Dominican Republic.

One species is described in this paper. The second

remains undescribed because it is represented by

a single immature shell that does not show

definitive characteristics of its species. These two

snails are tentatively assigned to Mcleania

because of similarities in shell structure to M.

dmiingtoni. They differ from M. darlingtnni in

important characteristics of the sculpture, as well

as several other traits. No live specimens of the

two new taxa were found, and a more satisfac-

tory basis for relating them to M. dariingtoni

cannot be given at this time.

Field work in the Dominican Republic was

sponsored by the Florida State Museum and the

National Geographic Society, Committee for

Research and Exploration. I am grateful to of-

ficials of both organizations for making this field

work possible.

Mcleania tumidula new species

(Fig. 1, A-C)

S/?r//. -Depressed helicord, about 0.,53-0.67

times as high as wide; medium sized, being about

78 THE NAUTILUS

April 25,1977

Vol. 91 (2)

FIG. 1. A-C Mcleania tumidula neiv species, holotifpe (UF

227:16). U.6 mm in width. D-F Mcleania darlin^imi Be-

1.5 mm wide. Color uniform light brown. Shell

opaque. Spire low, obtuse, nearly flat sided,

slightly convex in outline. Base inflated. Whorls

rapidly increasing in size, keeled, with about

19-21 obliquely compressed knobby serrations

along the periphery that form a scalloped fold

around the shell. 'Die peripheral interior of the

shell is indented beneath the knobs. Body whorls

nearly flat above the periphery, strongly inflated

quaert and Clench: 30 km. N.N. W.. 3 km K Ponce. Puerto

Rim. mm-ll.iO m. alt. (UF 22738).

below: descending very slightly along its last

quarter. Umbilicus narrow, about 1/25 the

diameter of the shell. Umbilicus partially

obscured by reflected columella. Adult shell with

3.6 whorls, and having 1.4 embryonic whorls.

First embryonic whorl smooth. Subsequent em-

bryonic portion with weak incremental growth

wrinkles. First quarter of post -embryonic whorl

with fine incremental thread-striations that are

Vol. 91 (2)

April 25, 1977

THE NAUTILUS 79

replaced rapidly by heavy cord-like folds extend-

ing halfway across the whorl from the suture.

Folds more or less alternating with compressed

knobs along the periphery. Superimposed on the

cords is an oblique series of irregular, fine zig-zag

striations that tend to become corrugated near

the periphery and on the knobs. Base of shell

with fine, irregular, incremental striations bear-

ing superimposed and finer, short, scattered, zig-

zag striations that tend to corrugate the base.

Aperture broadly auriculate, deeply indented by

previous whorl. Peristone simple, thin, weakly

reflected, incomplete across parietal wall. Dorsal

lip nearly straight. Columellar margin moderate-

ly reflected over umbilical area. Parietal callus

thin, transparent, strongly recurved near um-

bilicum. nearly straight otherwise.

Measurements in mm of the three known

specimens are:

Type Locality— DominicsLn Republic, Barahona

Prov., Loma Cana Brava, 6 km. E, 6 km. NNE

Polo, 1370 m. alt. Holotype: UF 22736: collected

18 January, 1976 by Fred G. Thompson. Para-

types: UF 22735(2); same locality as the holotype.

The type locality is in a wet mountain forest

at the crest of the mountain Loma Cana Brava.

The microhabitat occupied by the snail was not

determined for live specimens were not en-

countered. The shells comprising the type series

were found on the ground under limestone slabs

on densely shaded moss and lichen covered knolls.

Remarks— Mcleania tumidida can be compared

with two other species, M. darlingtoni from Puer-

to Rico and another undescribed species from

Hispaniola to which it is more closely related. It

differs from M. darlingtoni in numerous details.

The shell is much larger, attaining a major

diameter of about 15 mm. It has a broadly obtuse

raised spire, resulting in a height/width ratio of

about 0.53-0.67. The whorls are much more in-

flated, and have more (19-21) but much weaker

serrated nodes per whorl along the periphery.

The umbilicus is much narrower, being about

1/25 the width of the shell. The peristome is in-

complete across the parietal wall, and the outer

lip is only slightly reflected. The periostracum is

nearly smooth, having weak incremental stria-

tions and poorly defined oblique anastomosing

wrinkles. The embryonic whorls are smooth in-

itially, with weak incremental sculpture follow-

ing the first whorl.

M. darlingtoni is characterized by numerous

pecularities (Fig. 1, D-F). It attains a major

diameter of about 12 mm, and is planispiral with

a height/width ratio of about 0.36-0.38. The

whorls are relatively small in caliber and have

about 12-16 strong protruding nodes along the

periphery. The umbilicus is very broad and fun-

nel shaped, being about 1/3 the width of the

shell. The peristome is complete and the aperture

is slightly free from the preceding whorl. The

lusterless periostracum bears numerous course in-

cremental threads and fimbriations that form

scattered tufts on the base and apex. The

peripheral serrations are coursely marked with

radial periostracal fimbriations. Finally, the em-

bryonic whorls have rather course, strongly ob-

lique anastomosing wrinkles.

The differences between M. tumidida and M.

dnrlimjtiini are numerous and of such a mag-

nitude that a congeneric assignment of the two

species is only provisional. Most fundamental of

these differences is the sculpture. Until the soft

anatomy of M. tumidula is investigated the

systematic relationships and biogeographic im-

plications must be interpreted with caution.

An additional undescribed Mcleania occurs in

the Sierra de la Salle north of Pedernales, Peder-

nales Prov., Dominican Republic. A single im-

mature shell (UF 22737) was collected 1 km.

south of Altagracia, at 750 m. altitude in a cocao

grove. Compared to M. tumidida this other

species has course, irregular radial sculpture on

the spire, is nearly planispiral, and has a wide

umbilicus that is about 1/6 the diameter of the

shell. In other aspects it is more like M. tumidula

than M. darlingtoni.

80 THE NAUTILUS

April 25.1977

Vol. 91 (2)

LITERATURE CITED

Baker. H. B. 19.56. Family names in Pulmonata. The Nautiltis

69: 128-i:?9.

Baker. H. B. 1940. Some Antillean Sagdidae and Polygyridae.

The Nuut iliix 54: 54-62.

Qench. Wm. J. and J. Bequaert. 1939. Mcl€ania.ai new genus of

land mollusks from Puerto Rico. Meniorids dp la Siiripdntt

Ciibnmi fie Histinia Natural 13: 283-284; pi. %. fig. 4-6.

van der Schalie. H. 1948. The land and fresh-water mollusks

of Puerto Rico. Misc. Publ. Museum ofZool. Unii: Mich. 70:

1-133; pis. I-XIV.

RECENT DEATHS

Alberto Carcelles, well-known and leading

malacologist of Argentina, died Januar\' 23. 1977.

in Alta Gracia. Cordoba. Argentina, at the age of

81. Dr. Carcelles taught at the University in

Buenos Aires and was for years Chief of the In-

vertebrate Section, in the Museo Argentina de

Ciencias Naturales. He was bom in Buenos Aires

on July 18, 1897. He authored many works on the

marine mollusks of Uruguay and Patagonia.

Among his students was Dr. J. J. Parodiz of

Pittsburgh. Pa.

John Dyas Parker, malacological archivist for

the Delaware Museum of Natural History and

long-time assistant to Henry A. Pilsbn,' at the

Academy of Natural Sciences of Philadelphia,

died February 2, 1977, of a heart attack, in Penn-

sylvania, at 61. He stimulated interest in mol-

lusks among amateurs who funded the Pilsbr>'

Chair of Malacology, and was a co-founder of the

Philadelphia and Wilmington Shell Clubs. He

was active in paleonto logical field work and cave

exploration. Jack was born June 5, 1915. in

Woodhaven, Long Island, N. Y. where he is now

bui'ied.

Willard Lee Mohorter, fonner publisher and

private shell collector, died October 19, 1976, in

Cincinnati, Ohio, at the age of 88. He and his late

wife travelled extensively from 1936 to 1975 in

search of mollusks. He was honorary curator of

mollusks at the Cincinnati Museum of Natural

Histor>' and donated part of his collection to that

institution. He was born in Kiamensi, Delaware,

October 4, 1888. A short, posthumous biography

of "Mr. Mo" appeared in the Hawaiian Shell

Npuv. February 1977.

Esther Brooks Hadley, well-known shell dealer

in Newton, Massachusetts since 1936, died in

North Adams, Massachusetts, on September 9,

1976 at age 87. Formerly, she worked for the

Veterans Administration in Boston. She and her

late husband, F. Knight Hadley, operated a shell

mail order business for forty years. Her collection

is for sale by her son, Norman, of Jacksonville,

Vermont 05432.

Kenneth R(ichard) H(odgson) Read, biochemist

and marine biologist at Boston University, died

February 24. 1977. at 48, in Boston, Mass. He was

well-known for his underwater photography, and

published on myoglobins in mollusks. He was

born Spetember 9. 1928, in Dinas Powis, Wales,

and obtained a Ph. D. at Harvard University in

1963.

Albert B(ernhard) Kettell, for years a pastor

of the United Church of Christ in New England,

an Army Chaplain during World War II, and an

ardent shell collector, was born in Somerville,

Mass., March 7, 1896. He was a member of the

A.M.U. for 25 years and a former President of

the Connecticut Valley Shell Club. Reverend

Kettell amassed a large collection of shells, and

retired to Clearwater, Florida, where he died

December 30, 1976, at the age of 81. He is sur-

vived by his wife, Clara Dito Kettell. See Ameri-

can Malnrologi<>tii. 1975 supplement, p. 555.

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MOLLUSK VOUCHER SPECIMENS

It is becoming increasingly important for

future research purposes that an identified sam-

pling of species mentioned in publications be

deposited in a permanent, accessible museum

specializing in moUusks. This is particularly

true of moUusks used in physiological, medical,

parasitological, ecological, and experimental

projects.

The Delaware Museum of Natural History

has extensive modern facilities and equipment

for the housing and curating of voucher

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JULY 1, 1977

THE

NAUTILUS

Vol. 91

No. 3

A quarterly

devoted to

malacology and

the interests of

conchologists

Founded 1889 by Henry A. Pilsbry. Continued by

Editor-in-Chief: R. Tucker Abbott

H^,

urrington Baker.

EDITORIAL COMMITTEE

CONSULTING EDITORS

Dr. Arthur H. Clarke, Jr.

Division of Molluslts

National Museum of Natural History

Washington, D. C. 20560

Dr. William J. Clench

Curator Emeritus

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. William K. Emerson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 10024

Mr. Morris K. Jacobson

Department of Living Invertebrates

The American Museum of Natural History

New York, New York 10024

Dr. Aurele La Rocque

Department of Geology

The Ohio State University

Columbus, Ohio 43210

Dr. James H. McLean

Los Angeles County Museum of Natural History

900 Exposition Boulevard

Los Angeles, California 90007

Dr. Arthur S. Merrill

Biological Laboratory

National Marine Fisheries Service

Oxford, Maryland 21654

Dr. Donald R. Moore

Division of Marine Geology

School of Marine and Atmospheric Science

1 0 Rickenbacker Causeway

Miami, Florida 33149

Dr. Joseph Rosewater

Division of MoUusks

U. S. National Museum

Washington, D.C. 20560

Dr. G. Alan Solem

Department of Invertebrates

Field Museum of Natural History

Chicago, Illinois 60605

Dr. David H. Stansbery

Museum of Zoology

The Ohio State University

Columbus, Ohio 43210

Dr. Ruth D. Turner

Department of Mollusks

Museum of Comparative Zoology

Cambridge, Mass. 02138

Dr. Gilbert L. Voss

Division of Biology

School of Marine and Atmospheric Science

10 Rickenbacker Causeway

Miami, Florida 33149

Dr. Charles B. Wurtz

3220 Penn Street

Philadelphia, Pennsylvania 19129

EDITOR-IN-CHIEF

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Delaware Museum of Natural History

Box 3937, Greenville, Delaware 19807

Mrs. Horace B. Baker

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Havertown, Pennsylvania 19083

OFFICE OF PUBLICATION

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Second Class Postage paid at Wilmington, Delaware

Subscription Price; $8.00 (see inside back cover)

THE

NAUTILUS

Volume 91, number 3 — July 1, 1977

CONTENTS

William K. Emerson

Notes on Some Indo-Pacific Species of Modi w (Gastropoda; Tonnacea) 81

Helen DuShane

A New Abyssal Amaea (Gastropoda: Epitoniidae) from the North Eastern Pacific Ocean ST'''

Helen DuShane

Epitonmm textimattum, a New Gastropod from the West Coast of Mexico 89

Craig M. Doremus and Willard N. Harman

The Effects of Grazing by Physid and Planorbid Freshwater Snails on Periphyton 92

Ralph W. Dexter

A Further Note on Geologic Changes in the Relative Size of Bivalve Shells 96

Kathleen A. Burky and Albert J. Burky

Buoyancy Changes as Related to Respiratory Behavior in an Amphibious Snail,

Pomacea urceus (Muller), from Venezuela 97

Clement L. Counts, III, John M. Dingess and James E. Joy

The Electrocardiogram of the Freshwater Bivalve Lcimp.s-i'/is radiata (Bivalvia: Unionidae) 105

Dee S. Dundee

Observations on the Veronicellid Slugs of the Southern United States 108

Steven T. Malek

VeroniceUa occidentalis in Louisiana 115

Ralph W. Taylor, Michael P. Sweeney and Clement L. Counts, III

Use of Empty Gastropod Shells (Polygridae) by Pseudoscorpions 115

Publications received 117

)1 (:5)

Julv 1, 1977

THE NAUTILUS 81

NOTES ON SOME INDO-PACIFIC SPECIES OF MORUM

(GASTROPODA: TONNACEA)

William K. Emerson

American Museum of Natural History

New York. New York 10024

ABSTRACT

Descriptive and distributional data are given for three poorly known and

misunderstood species of Morum from the Indo-Paciflc. Additional specimens of

Morum (Oniscidia) exquisitum are reported from the Subi Sea, and records other

than those from the Philippines are rejected. Morum (0.) praeclarum, a species

previously reported from deep water off Natal and Zuiuland. South Africa is

reported from four stations in the western Indian Ocean. The recorded range of

Morum (Herculea) ponderosum is extended to include New Caledonia and the Pit-

cairn Islands.

Specimens of two poorly known Indo-Pacific

species of the genus Morum, namely: Morum ex-

quisitum (Adams and Reeve, 1848) and M.

praeclarum Melvill, 1919, have recently come to

the attention of the writer. Morum exquisittim

was described from a unique specimen obtained

by Arthur Adams in the Philippines during the

celebrated voyage of the HMS Samarang to the

western Pacific and Indian Oceans, from 1843 to

1846. Despite the fact that this species, based on

the type specimen dredged in the Sulu Sea, was

well-described and illustrated by Adams and

Reeve (1848, 1850) and by Reeve (1849), the iden-

tity of this taxon has remained uncertain owing

to its extreme rarity in collections. Most subse-

quent workers followed Tryon (1885) who con-

sidered it to be conspecific with Morum

ponderosum (Hanley, 1858), a distinct species

originally described from an unknovra prove-

nance. The two species were finally separated by

Melvill (1919), and he correctly recorded M.

ponderosum from Japanese waters.

Through the good offices of Dr. Joel Greene of

San Francisco, California, a mature, live-taken

specimen of Morum exquisitum (figures E, F, J)

was recently brought to my attention. This

specimen, together with a dead one, was taken by

divers in shallow depths off Laminusa, Sulu,

Philippines. Now in the collection of the Ameri-

can Museum of Natural History (cat. no. 183926),

this specimen compares favorably in all details

with the figured holotype, except it is slightly

larger with 5 post-nuclear whorls, and has 12 ax-

ial ribs on the body whorl. The apex is colored

a pale pink, whereas the parietal shield and the

blotches on the outer lip are a light purple-pink.

Of the livmg species of Morum, it appears to be

most closely related to the New World "twin

species," M. veleroae Emerson, 1968, from the

eastern Pacific, and to M. dennisoni (Reeve,

1842), from the Western Atlantic. Attesting to

the rarity of M. exquisitrim, I was able to locate

only two other specimens in institutional collec-

tions.

Compared to M. exquisitum, M. ponderosum

(figures G, H, I) has a heavier shell, which is

more triangular in outline, with coarser orna-

mentation and a much lower spire. The parietal

wall is heavily callused and the non-pustulose,

flattened shield covers most of the apertural side

of the body whorl. Numerous weakly formed, ir-

regular folds extend down the perietal wall into

the aperture. The outer lip is thickened and the

inner margin is dentate; the lip extends poster-

iorly to the penultimate whorl to form a deep

sulcation. The shell, including the apex, is colored

creamy white with occasional streaks and blotch-

es of reddish brown, which are especially prom-

inent on the reflected surface of the outer lip.

The parietal shield is suffused with creamy tan

and is variegated with reddish brown markings.

82 THE NAUTILUS

July 1. 1977

Vol. 91 (3)

Perhaps one of the reasons Tryon (1885) erro-

neously concluded that M. exquisitum and M.

ponderosum were the same species was the result

of the artist's lapsus in coloring the original

figures (Hanley, 1858) of M. ponderosum reddish

purple, instead of the natural reddish brown col-

oration that is characteristic of this species.

Morum praeclarum Melvill, 1919 was described

from a unique specimen lacking locality data ob-

tained from the collection of J. J. MacAndrew,

FIGS. A-D Morum (0.) praeclarum MehnU; A-B Faqhuar Gniup. Seychelk hUimitt. in «/ m.. A' A/A// ho.

71862. C-D Holotypc. MehnU-Tomlin OAl. NMW (Courtesy of Naiional Museum of Wales): A-D about 3A natural size. E.

F, J Morum (0.) exquisitum (Adam.': & Reeve): Lattiimiita, Sulu Sen, Philippines, in li m.. AMNH No. }SS92(>: E, F about S/J,

natural size: J spire greatly enlarged to show protoconch. G. H, I Morum (H.) pondero.sum (Hanley): Oeno Island. Pitcaim

Islands, off reef. NMNH No. /.ilflOI: G, H about S/i natural size: I spire greatly enlarged to. ih/'upriitnrinirh.

Vol. !)1 CA)

July 1, 1!»77

THE NAUTILUS 83

for whom Monim macandreui (Sowerby, 1889)

had been named 30 years previously. Although

the type specimen of M. praeclarum was il-

lustrated recently in color (Dance, 1971), no addi-

tional material had been recognized until

Kilburn (1975) reported it from South Africa. Dr.

Joseph Rosewater uncovered five specimens in

the National Museum of Natural History collec-

tions. An additional specimen was located in the

Delaware Museum of Natural History by Dr. R.

Tucker Abbott. These specimens were dredged by

the "Anton Bruun".

TVie newly discovered specimens of M. prae-

clanini (figures A, B) are more diminutive than

the holotype (figures C, D), the largest being 30.3

mm in length, compared to 40 mm for the type

specimen. Othenvise they agree well in essential

characters with the description and illustrations

of the holotype (Melvill, 1919; Dance, 1971).

Melvill believed this species to be "nearest" to M.

exquisitum, but he also compared it to M. macan-

dreui. to which it is actually more closely

related. It differs, however, from M. macandreui

in several respects. The shell is smaller, propor-

tionally more robust and less pyriform in out-

line; the axial ridges are more delicate and they

form sharp, scalelike spines at the intersections

of the spiral ridges; the parietal shield is thickly

enameled, finely ornamented with pustules an-

teriorly and lineations posteriorly, and the den-

ticles on the outer lip are confined to the aper-

tural surface. Dance's illustration (1971, p. 119)

suggests that the brownish spiral bands are well-

developed on the holotype. In the present speci-

mens, these bands are more diffused and are

most prominent on the reflected surface of the

outer lip and the adjoining portion of the body

whorl. In these specimens, the surface is suffused

in huffish cream and the spiral bands form

streaks of light brown. As in the holotype, the

aperture, outer lip, and parietal shield are a

milky white.

TAXONOMY

In a revision of the southwestern Pacific

species, Beu (1976) reviewed the taxonomic status

of the genus Morum Roding, 1798, type species by

monotypy: Morum purpureum Roding, 1798

{= St nimbus onisctis Linnaeus, 1767). In addition

to the nominate subgenus, he recognized two

subgenera: (1) Onisddia Morch, 1852, type species

by monotypy: Onkcia cancellata Sowerby, 1824;

(2) Herculea Hanley, in H. and A. Adams, 1858,

type species by monotypy: Oniscia ponderosa

Hanley, 1858.

The attribution of the first valid use of

Oniscidia to Morch, 1852, by action of the Inter-

national Commission of Zoological Nomenclature

(Opinion 1040), precludes the use of Cancel-

lomorum Emerson and Old, 1963, type species by

original designation: Oniscia grandis A. Adams,

1855, and Onimusiro Kira, in Kuroda, Habe, and

Oyama, 1971, with the same type species and

method of designation. Both of these rejected

taxa, which are currently widely used respective-

ly in the American-European literature and in

the Japanese literature, thus become junior sub-

jective synonyms of Oniscidia Morch. Beu (1976)

also referred Pulchroniscia Garrad, 1961, type

species by monotypy: Pulchroniscia delecta Gar-

rad, 1961 {^Oniscidia bruuni Powell, 1958, fide

Beu, 1976), to the synonymy of Oniscidia Morch.

Because generic synonymies of Morum sensu lata

are given by Beu (1976), they are not repeated

here.

INDO-PACIFIC SPECIES

In addition to the three species discussed

below, the following nominal species of Morum

are known from the Indo-Pacific: M. (Oniscidia)

cancellatum (G. B. Sowerby, I, 1824); M. (0.)

grande (A. Adams, 1855); M. (0.) macandrewi (G.

B. Sowerby, III, 1889; M. (0.) bruuni Powell,

1958; M. (0.) teramachii Kuroda and Habe, in

Habe, 1961; M. (0.) iwhiyjamai Kuroda and Habe,

in Habe, 1961; and M. (0.) watsoni Dance and

Emerson, 1967: quod vide for citations to the

original descriptions.

Morum (Oniscidia) exquisitum

(Adams and Reeve, 1848)

Figures E, F, J

Oniscia exquisita Adams and Reeve, in Adams,

1848, p. 35 [text p. 35, issued in May, 1850], pi.

5, figs. 3a, 3b, [References To Plates, p. x and

pi. 5, issued in November, 1848], "Sooloo [Sulu]

Archipelago; outside a coral reef near the city

84 THE NAUTILUS

July 1, 1977

Vol. 91 (3)

of Sooloo (Jolol in about sixteen to twenty

fathoms, sandy mud." Reeve, 1849 [issued in

August], vol. 5, Oniscia pi. 1, fig. 3, "Sooloo

[Sulu] Archipelago" [repeats data of Adams

and Reeve, 1850].

Oniscia exquisita Reeve, Kiister, 1857, p. 58, pi.

55, fig. 10 (after Reeve, 1849, fig. 3), "Soulou-

Archipel von Belcher entdeckt."

Oniscia (OniscidiaJ exquisita Adams and Reeve,

Tryon, 1885, p. 282, pi. 8, fig. 100 (after Reeve,

1849, fig. 3), "Sooloo [Sulu] Sea; Australia."

Morum (Oniscidia) exquisitum, Melvill, 1919, p.

72, "Sooloo [Sulu] Archipelago [etc.], Philippine

Isles (Hidalgo), Japan (Hirase), Saya de Malha

Banks, S. Indian Ocean (J. Stanley Gardiner)."

Morum exquisihim Adams and Reeve, Abbott,

1962, p. 66, color illus., "Philippines, rare."

Tifpe depository: not known (Melvill, 1919, p.

72; Dance and Emerson, 1967, p. 95). The

specimen figured by Reeve (1849), the apparent

holotype, was sold in 1865 when the famous col-

lection of John Dennison was disposed by public

auction in London (Melvill, 1919; Dance, 1966, p.

210). The holotypic specimen is apparently lost.

Type locality: off Jolo [Sulu City], Sulu Island,

Sulu Archipelago, Philippines, in 30 to 36 meters.

Verified geographic range: Known only from

the Sulu Archipelago, Philippines, in 6 to 36

meters.

Material examined: Philippines: 6 meters,

Laminusa, Sulu Archipelago, 1 specimen, 46.7

mm in length, 27.4 mm in width, ex Joel Greene,

AMNH 183926; Tawi-Tawi, Sulu Archipelago, 1

specimen 30.3 mm in length, 19.5 mm in width,

ex Mrs. P. Bautista, ANSP 218411, illustrated in

Abbott (1962, p. 66); Zamboanga, Mindanao, 1

specimen, 32.4 mm in length, 22.5 mm in width,

NSMT .54630.

Remarks: The early citations in the literature

to records from Japan, Australia, and the Indian

Ocean appear to be erroneous. Dr. Habe (personal

communication) has no knowledge of specimens

from Japanese waters. The specimen in the

British Museum (Natural History) reported by

Melvill (1919) from the Indian Ocean was sent to

me on loan. It is apparently referable to Morum

praeclarum Melvill, being a badly worn, broken

and discolored juvenile shell. The Japanese and

Australian records were based most likely on

misidentified specimens of M. (H.) ponderosum.

At the present time M. (0.) exquisitum is known

only from the Sulu Sea.

Oniscia exquisitum Adams and Reeve dates

from November 1848, when the name was applied

to figures 3a, 3b of plate 5 in the "References To

Plates, Mollusca" of the Zoology of the Voyage of

the H.M.S. Samarang. The description appeared

subsequently, in May 1850, when the text was

issued.

Morum (Oniscidia) praeclarum Melvill, 1919

Figures A— D

Morum praeclarum Melvill, 1919, p. 69, text fig.

"Hab.[itat]?" J. J. MacAndrew Coll. Dance,

1971, p. 119, fig. 5, "locality unkown"; 1975,

Kilburn, p. 49, "off Mvoti River, 56 fms., and

off Durban, South Africa, 160 fms."

Type depository: holotype, here illustrated,

figures C— D, Melvill-Tomlin Collection, National

Museum of Wales, Cardiff (Dance and Emerson,

1967, p. 95); N.M.W. accession No. 55.158, teste

June Qiatfield.

Type locality: 11 mi. off Port Shepstone, South

Aft-ica in 2.50 fathoms. (Kilburn, 1975).

Verified geographie range: western Indian

Ocean; off Somali Republic and Mozambique,

Africa; Seychelle Islands, in 78 to 132 meters off

South Africa.

Material examined: Africa; 80 miles E. of Ras

Mabber, N.E. Somali Republic; 78-82 meters, 1

specimen, 28.6 mm in length, 20.1 mm in width,

"Anton Bruun," Sta. 9-445, 09°36' N. Lat.. 5r01

E. Long., ex Harold Vokes, DMNH 117851; off

Mozambique; ca. 40 miles E. Quissico, 132 meters,

2 specimens, 30.3 mm in length, 21.1 mm in

width, .30.1 mm in length, 19.1 mm in width, "An-

ton Bruun," Cruise 7, Sta. 371-E, NMNH 761345.

Seychelle Islands: ca. 80 meters, Faqhuar Group,

1 specimen, 26.7 mm in length, 17.2 mm in width,

"Anton Bruun" Cruise 9, Sta. 444, 09°36' N. Lat.,

5r01' E. Long., NMNH 718962; ca. 90 meters, Fa-

qhuar Group, 2 specimens, 24.8 mm in length,

17.2 mm in width, 2.3.2 mm in length, 16.4 mm in

width. "Anton Bruun" Cruise 9, Sta. 437, 09°25'

N. Lat., .50%54' E. Long., NMNH 718953.

Remarks: At my request, Dr. June Chatfield

kindly compared the holotype of M. pnurlannii

with the illustration of the type specimen in

Dance (1971, p. 119, fig. 5). She concluded that the

Vol. 91 (3)

Julv 1, 1977

THE NAUTILUS 85

figure is fairly accurate in color, but it is perhaps

a little darker than the holotypic specimen. The

East African provenance of this species has been

revealed through the dredging operations of the

"Anton Bruun" in the Indian Ocean. Additional

unrecognized specimens of this species probably

exist in the extensive collections made in recent

years from this region.

Morum (Herculea) ponderosum (Hanley, 1858)

Figures G. H, 1

Oniscia ponderosa Hanley, 1858, pp. 255, 256, pi.

42, fig. 9, 10, "Hab[itat]?," Cuming Coll. Tryon,

1885, p. 282, pi. 10, fig. 22 (after Hanley, 1858,

fig. 10), [incorrectly cited as a synonym

of Morum exquisitum (Adams and Reeve)).

Stearns and Pilsbry, 1895, "Yaeyama" [Ryukyu

Islands], incorrectly cited as "Oniscia

exquisita," which, following Tryon, was con-

sidered to be a synonym of Morum pondero-

sum.

Monim ponderosum (Hanley), Hirase and Taki,

1951, pi. 98, fig. 2, "Amami-Oshima," Ryukyu

Islands. Kuroda and Habe, 1952, p. 68, Range:

0-29° North Latitude. Oyama and Takemura,

1961, pt. 5, Morum pi. 2, figs. 4, 5, "Amami-

Oshima Isl."

Morum (Herculea) ponderosum (Hanley), H. and

A. Adams, 1858, p. 621. Melvill, 1919, p. 71,

"Japan (Steams)." Shikama, 1963, p. 59, pi. 42,

fig. 4 "Amami-Oshima, Ryukyu Group, Japan."

Habe, 1964, p. 69, p.. 21, fig. 1, "rare, Amami

and Ryukyu Islands, wide-ranging in the Indo-

Pacific regions." Shikama, 1964, p. 114, fig. 193.

Ponder, in Beu, 1976, p. 224, "Herald Cay and

Lady Elliot Island, Queensland."

Type depository, Lectotype: BM(NH) No.

1966724, ex Hugh Cuming Collection, selected by

Dance and Einerson (1967, p. 94); syntype BM-

(NH) No. 196625, ex Hugh Cuming Collection.

Type locality; Amami-Oshima, Ryukyu Islands,

here designated.

Verified geographic range: Ryukyu Ar-

chipelago, Japan; Queensland, Australia (fide

Beu, 1976); New Caledonia; and the Pitcairn

Islands.

Material examined: Japan: Ryukyu Islands:

"Oshima Osumi" [Amami-Oshima], 2 specimens,

47.8 mm in length, 31.5 mm in width, 34.5 mm in

length, 21.6 mm in width, Hirase Coll., NMNH

34938; Amami-Oshima, 1 specimen, 31.7 mm in

length, 21.8 mm in width, Hirase Coll., MCZ

43262; Amami-Oshima, 2 specimens, 45 mm in

length, 28.5 mm in width, 32 mm in length, 22.8

mm in width, Hirase Coll., ANSP 98020; Amami-

Oshima, 1 specimen, 22 mm in length, 18.2 mm in

width, A. R. Cahn Coll., ANSP 275543; Okinawa,

Onna sand flat, 1 specimen, 38.6 mm in length,

26.7 mm in width, Bemice Albert, leg., ANSP

276387; Okinawa, Kadena, 1 specimen, 36.6 mm

in length, 24 mm in width, Rose Burch Coll.,

AMNH 114571; Okinawa, Kadena, 1 specemen,

37.3 mm in length, 25.8 mm in width, W. A. Mc-

Carty, leg., AMNH 183950.

New Caledonia: 1 specimen, C. T. Trenchmann

Coll., BM(NH) 1964504, teste A. F. Blake.

Pitcairn Islands: off reef, N. coast of atoll,

Oeno Island, 1 specimen, 41 mm in length, 27.8

mm in width, H. A. Rehder leg., NMNH 731601:

Henderson Island, 1 specimen, J. R. Jamieson and

D. K. Tait leg., BM(NH) 1913.7.28.90, teste A. F.

Blake.

Remarks: According to Dr. Tadashige Habe

(personal communication) sf)ecimens from the

Hirase Collection bearing the locality Oshima

Osumi are from Amami-Oshima of the Amami

Group in the Ryukyu Archipelago. Early records

attributed to "Japan" are actually referable to

the Ryukyus and Okinawan Islands. The disjunct

distribution of the uncommon species apparently

represents gaps in collecting in the intermediate

areas, rather than a relict distributional pattern.

ACKNOWLEDGMENTS

I am indebted to the following curators for pro-

fessional courtesies of various kinds: Drs. R.

Tucker Abbott, Delaware Museum of Natural

History (DMNH); June Chatfield, National

Museum of Wales (NMW); Kenneth J. Boss,

Museum of Comparative Zoology, Harvard

University (MCZ); George M. Davis, Academy of

Natural Sciences of Philadelphia (ANSP);

Tadashige Habe, National Science Museum,

Tokyo (NSMT); Joseph Rosewater, National

Museum of Natural History, Smithsonian Institu-

tion (NMNH); and John Taylor and Miss A. F.

86 THE NAUTILUS

Julv 1. 1977

Vol. 91 (3)

Blake, British Museum (Natural History)

(BMNH). I thank my colleague, Mr. William E.

Old, Jr., for technical assistance.

LITERATURE CITED

Abbott, R. T. 196Z Sea shells of the World. Golden Press, New

YorkieOp.. illus.

Adams, Arthur. 1855. Descriptions of new genera and species

of gasteropodous [sic] Mollusca. Proc. Zool. Soc. London 21:

182-186.

Adams, Arthur, and Lovell Reeve. 1848-.50. Mossusca. In A.

Adams, The zoology of the voyage of H.M.S. Samarang;

under the rommand of Captain Sir Edward Belcher. London

(see Keen, 1971, p. 971, for dates of publication).

Adams, Henry, and Arthur. 1853-,58. The genera of Recent

Mollusca; arranged according to their organization. London,

3vols.,661p., 138 pis. (dates of publication: vol. a p. 661).

Beu. A. G. 1976. Revision of the southwest Pacific species of

Manan {(Miscidia). Juur. Malac. Soc. Australia 3(4):

223-231.

Dance, S. P. 1966. Shell Collecting: an Illustrated History.

Univ. Calif Press, Berkeley and Los Angeles, 344, p., 35 pis.

Dance, S. P. 1971. Seashells. Hamlyn, London, 159 P., illus.

Dance, S. P. and W. K. Emerson. 1967. Notes on Monim den-

nisoni and related species. The Veliger 10(2): 91-98, pi. 12.

Einerson. W. K. 1968. A new species of the gastropod genus

Murum from the eastern Pacific. Jour, de Conchyl., 107(1):

.5.3-.57,pl. 1.

Emerson, W. K., and W. E. Old, Jr. 1963. Results of the

Puritan-American Museum of Natural History Expedition

to western Mexico. 19. The Recent Mollusks: Gastropoda,

Strombacea, Tonnacea, and Cymatiacea. Amer. A/)is.

Novitates, 21,53. .38 p., 28 figs.

Garrard. T. A. 1961. Mollusca collected by M. V. "Challenger"

off the coast of Australia. Jour. Malac. Soc. Australia 1(5):

2-37, pi. 12.

Habe, Tadashige. 1964. Shells of the Western Pacific in Color

2. English ed., Hokusha, Osaka, Japan. 233 p.

Hanley, Sylvanus. 18.58. Description of a new Oniscia. Pruc.

Zool. Soc Londm 26: 2.5,5-256, pi. 42.

Hirase, Shintaro, and Isao Taki. 1951. A Handbook of Il-

lustrated Shells, in Natural Cohrs. Tokyo, 134 pis. + 46.p.

International Commission on Zoological Nomenclature. 1975.

Opinion 1040, Oniscidia Mbrch, 1852 (Mollusca): Placed on

the Official List. BuU. Zool Nomen. 32(3): 139-140.

Kilbum. R.N. 1975. The rediscovery of Morum pmeclarum

Melvill (Ca-ssidae). 77!eA«i((i7M.s89(2):49-.50.

Keen, A. M. 1971. Sea Sheik of Tropical West America. Stan-

ford Univ. Press, ed. 2, xiv + 1064 p.. illus.

Kuroda, Tokubei, and Tadashige Habe. 1952. Checklist and

Biblitiyraphy of the Recent Marine Mollusca of Japan,

Tokyo, 210 p.

Kuroda, Tokubei. T. Habe, and K. Oyama. 1971. The Sea

Shells <}fSayami Bay Collected by His .Majesty the Emperor

of. Japan. Tokyo, 751 -(-489-1- 51 p., 121 pis.

Kiister, H. C. |1846| - 18.57. Systematisches Conchylien-

Cabinet.Sd): 5.3-59; pi. 5.5.

Linnaeus, Carl. 1767. Systema naturae per regna tria naturae.

Editio duodecima, reformata, pt. 2, p. ,533-1327..

Melvill, J. C. 1919. Description of Morum praeclarum, sp. no.,

with remarks on the Recent species of the genus. Proc.

Malm: &.C. Lorukm 13(3, 4): 69-72, 1 fig; Addendum, Itrid,

13(.5.6):145

Mfirch, 0. A. L. 18.52. Catalogus conchyliorum . . . de Yoldi,

Regis Daniae. Copenhagen, Fac. 1, 170 p.

Oyama, Katura, and Yoshio Takemura. 1961. The Molluscan

Shells, Resources Exploitation Institute, Tokyo, pt. 5,

Morum pis. 1,2.

Powell, A. W. B. 1958. Mollusca of the Kermadec Islands. Pt.

1. Records Auckland Inst.&Mus. 5(1-2): 65-8,5, pis. 9-11.

Reeve, L. A. 1842. Conchologia Systematica, or Complete

System ofConchology. London, Paris, Berlin, vol. 2.

Reeve, L. A. 1849. Monograph of the genus Oniscia, In, Con-

chologia Iconica, London, vol. 5. 1 pi.

Roding, P. F. 1798. Museum Boltenianum . . . pt. 2, Conchylia.

Hamburg, vii -I- 109 p.

Shikama, Tokio. 1963. Selected Shells of the World Illustrated

in Colours, vol. 1. Tokyo, 154 p., 102 pis., 211 figs.

Shikama, Tokio. 1964. Selected Sheik of the World Illustrated

in Colours, vol. 2. Tokyo, 212 p., 70 pis., 245 figs.

Sowerby, G. B., I. 1824. TTie Genera of Recent and Fossil

Shells. London, vol. 1, Oniscia pi. 233.

Sowerby, G. B., III. 1889. Descriptions of fourteen new species

of shells from China, Japan, and the Andaman

Islands... fVoc. Zool. Soc. London for 1888, p. .5&5-570, pi.

28.

Stearns, Frederick, and H. A. Pilsbry. 1895. Catalogue of the

Marine Mollusks of Japan. Detroit, 196 p., 11 pis.

Tryon. G. W.. Jr. 1885. Manual of Conchology. Philadelphia,

ser. 1, vol. 7, Family Cassididae, p. 268-283, 10 pis.

Vol. 91 (3)

July 1, 1977

THE NAUTILUS 87

A NEW ABYSSAL AMAEA (GASTROPODA: EPITONIIDAE) FROM THE

NORTH EASTERN PACIFIC OCEAN

Helen DuShane'

1M12 El Soneto Drive

Whittier, California 90605

ABSTRACT

Amaea siapnoi new species, a deepwater epitoniid, is described from a location

about 540 nautical miles southwest of Mas Revillagigedo, Mexico.

Species of Amaea are rare in the North Pacific

Ocean. Until now, no species of this genus has

been reported from the south eastern portion of

the North Pacific Ocean. Recently, I have re-

ceived, on loan, a live-collected specimen of a new

species of Amaea s. s. for purposes of identifica-

tion. Deepsea Ventures, Inc., May 1975, retrieved

this mollusk from 14,521 feet (4428.60 meters), ap-

proximately 540 nautical miles southwest of the

Islas Revillagigedo, Mexico.

Superfamily Epitoniacea

Family Epitoniidae

Genus Amaea H. and A. Adams, 1853

[Type species (SD, deBoury, 1909:

Scalaria magnifica Sowerby, 1844]

Subgenus ylmoea H. and A. Adams, 1853

Amaea (Amaea) siapnoi DuShane, n. sp.

(Figs. 1 and 2)

Shell medium in size, off-white in color;

nuclear and early postnuclear whorls missing, six

whorls remaining, gradually expanding to the

last whorl; sides of the whorls more perpen-

dicular than in most Amaea, giving it a columnar

outline; suture well-defined; costae curved and

retractive, lamellar near the distinct suture, worn

on the whorls, not continuous from whorl to

whorl; with a change of slope in the outline of

the whorls just below the suture, causing the

costae to curve rather abruptly; axial costae on

the last whorl 85, of varying thickness, sometimes

fusing with adjoining ones, continuous over the

base to the simple lip (outer lip partially

fragmented); with a poorly defined basal thread,

below which the sculpture is the same as that

above; spiral sculpture of approximately 16 to 22

uneven but mostly extremely wide ribs, separated

by narrow incised lines that cross the close-set

axial costae and impart to the shell a somewhat

beaded appearance; aperture round, lip thin; um-

bilicus lacking; operculum dark, round, horny.

Length 34 mm, width 12 mm (holotype).

Type Locality— Approximsitely 540 nautical

miles southwest of Isla Clarion, Islas

Revillagigedo, Mexico (14°50' N, 124°29' W), from

a depth of 4428.60 meters.

' Museum Associate, Department of Malacology, Los Angeles

County Museum of Natural History, Los Angeles, California

90007.

FIG. 1. Map showing approximate location where Amaea

(Amaea) siapnoi DuShane, n. sp. was taken in a dredge haul

from a depth ofUJ,28.60 meters.

88 THE NAUTILUS

July 1. 1977

Vol. 91 (3)

FIG. 2 Amaea (Amaea) siapnoi DuShane. n. sp. Left: Ven-

tral view. Length 31, mm. uidth 12 mm. Center: Dorsal

view. Right: Anterior portion enlarged to show poorly

defined basal thread. X 2

Type Material— Holotype, Department of

Marine Invertebrates, San Diego Natural History

Museum, San Diego, California: SDSNH 65482.

Etymology— The species name honors the chief

scientist of Deepsea Ventures, Inc., William Siap-

no.

DISCUSSION

Deepsea Ventures, Inc., working out of San

Diego, California, is involved in exploratory min-

ing for manganese nodules. William Siapno, chief

scientist of Deepsea Ventures, Inc., collected this

new species in May 1975. Other material in the

dredge haul included coarse, gritty manganese

that still adheres to the shell, manganese nodules,

large Carcharodon teeth, pelagic shark teeth

(probably of Miocene age), a whale ear-bone,

small brittle stars, and worm tubes.

The nuclear and immediate post-nuclear whorls

of the holotype are missing. One can only conjec-

ture that the live-taken specimen was damaged

in the dredge as it was retrieved.

Among the other Amaea collected in deep

water are Amaea (Scalina) ferminiana (Dall,

1908) from 118 to 1333 m off the coast of Peru by

the SEPBOP Program on the vessel ANTON

BRUUN (DuShane, 1974; 55); Amaea (Scalina)

pompholyx (Dall, 1908) collected in 1485 m near

the Galapagos Islands by the ALBATROSS (sta-

tion 2807) in ooze (DuShane, 1974; 56). These are

the only two records of Amaea (Scalina) from

deep water in the tropical eastern Pacific; these

depths do not approach the depth from which the

present species was taken. Comparison with

Amaea luxus Okutani, 1964, collected 56 miles off

Aogashima Island (32° 20' N, 140° 55.5' E), in

from 3,150 to 3,350 m, shows the two species to be

congeneric, each with an usually large number of

costae. The live-taken specimen of luxus differs

by having 140 (instead of 84) close-set costae on

the last whorl, a very elongate shell with 15

whorls, and a hardly distinguishable basal disk.

ACKNOWLEDGMENTS

To the following people I am indebted in many

ways; Drs. Myra Keen, Professor Emeritus, Stan-

ford University and George Radwin, Department

of Marine Invertebrates, San Diego Museum of

Natural History, for reading preliminary drafts

of the paper and providing constructive criticism;

to Bertram Draper, Museum Associate, Los An-

geles County Museum of Natural History, for the

photographs; to Anthony D'Attilio, Department

of Marine Invertebrates, San Diego Museum of

Natural History, for the map; to William Siapno,

Deepsea Ventures, Inc., and Dr. Hugh Bradner,

University of California, San Diego, for their help

in obtaining the holoptye for examination and

description.

LITERATURE CITED

Dall. W. H. 1890. Scientific results of exploration by the U. S.

Fish Commission steamer ALBATROSS. VII. Preliminary

report on the collection of Mollusca and Brachiopoda ob-

tained in 1887-88. Proc. USNM 12(773): 219-362, pis. 5-14. (7

March)

deBoury, E. A. 1909. Catalogue des sous-genres des Scalidae.

Jourii. de Conchyl. 57: 256-258.

DuShane. Helen 1974. The Panamic-Galapagan Epitoniidae.

The VeUger. Suppl. 16: 1-84, 154 photos, 1 map, 5 figs., 3

tables. (31 May)

Sowerby, G. B. (2nd) [\W1] 1847-1848. Thesaurus con-

chyliorum, or monograph of genera of shells, edited by G. B.

Sowerby, Jr.. completed by G. B. Sowerby 3rd. London, vol.

1, part 4:83-146; pis. 32-40. (11 April)

Vol. 91 (3)

July 1, 1977

THE NAUTILUS 89

EPITONIUM TEXTIMATTUM, A NEW GASTROPOD

FROM THE WEST COAST OF MEXICO

Helen DuShane

15012 El Soneto Drive, Whittier, California 90605

ABSTRACT

Epitonmm (Asperiscala) textimattum DiiShane, n. sp. (Gastropoda,) in dencrihed

from sublittoral water off the west Mexican states of Nayarit, Jalisco, and Colima.

It resembles E. walkerianum Hertlein and Strong.

Family EPITONIIDAE

Genus Epitonium Rbding, 1798 [Scala

of authors; Scalaria Lamarck, 1801]

Subgenus ylsperisca/a deBoury, 1909

Species referable to the subgenus Asperiscala,

with its type species of Scalaria bellastriata

Carpenter, 1864, are relatively common consti-

tuents of the Panamic-Galapagan fauna, there be-

ing 21 recognized species. The new species is

known only from the sublittoral zone, 7 to 18

meters, in a mud substrate, dredged from 4 sta-

tions off the states of Nayarit, Jalisco, and Co-

lima, Mexico.

Epitonium (Asperiscala) textimattum n. sp.

(Figs. 1-8).

Description: Shell medium to large in size,

elongate-conic, white, sturdy; nuclear whorls .3 to

4, horn-color, rounded, glassy, with a brown

sutural line, first two whorls small, subsequent

ones much larger and more bulbous with no

noticeable sculpture; fifth whorl down with

minute indentations and small axial ribs; post-

nuclear whorls 5 to 10, rounded, slightly sloping;