JANUARY 10, 1979

THE

NAUTILUS

ISSN (K)28-i:544

Vol. 93

No.l

A quarterly

devoted to

malacology and

the interests of

conchologists

Founded 1889 bv Henry A. Pilsbry. Continued by H. Burrington Baker.
Editor-in-Chief; R. Tucker Abbott

EDITORIAL COMMITTEE

CONSULTING EDITORS

Dr. Arthur H. Qarke, Jr.
Division of Mollusks
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. Einerson
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
Woods Hole Biological Laboratory
National Marine Fisheries Service
W(X)ds Hole, Massachusetts 02543

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 Mollusks
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. Charies B. Wurtz
3220 Penn Street
Philadelphia, Pennsylvania 19129

EDITOR-IN-CHIEF

Dr. R. Tucker Abbott
American Malacologists, Inc.
Box 4208, Greenville, Delaware 19807

Mrs. Horace B. Baker
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THE

NAUTILUS

Volume 93, number 1 — January 10, 1979

ISSN 0028-1344

CONTENTS

William K. Emerson and Anthony D'Attilio

Six New Living Species of Muricacean Gastropods 1

William K. Emerson and William E. Old, Jr.

Scaphella contoyensis, a New Volutid (Gastropoda) from East Mexico 10

W. Stephen Thomas

A Biography of Andrew Garrett, Early Naturalist of Polynesia: Part 1 15

Douglas S. Jones

The Nemertean, Malacohdella grossa, in the Ocean Qushog, Arctica islandica (Bivalvia) 29

Gary L. Pace, Ernest J. Szuch and Richard W. Dapson

Depth Distribution of Three Gastropods in New Mission Bay, Lake Michigan 31

Dorothy Blanchard and Lowell L. Getz

Arion subfuscus in Southeastern Michigan 36

David Pool and Jack McCullough

The Asiatic Clam, Corbicula manilensis, from Two Reservoirs in Eastern Texas 37

J. Roy Robertson

Evidence for Tidally Correlated Feeding Rhythms in the Eastern Mud Snail, Ilyanassa obsoleta .... 38

Edward B. Hatfield

Food Sources for Anachis avara (Columbellidae) and a Discussion of Feeding in the Family 40

Jean Ann Nichols and J. Roy Robertson

Field Evidence that the Eastern Mud Snail, Ryanassa obsoleta. Influences Nematode Community
Structure 44

Publications Received ii News ii

WANTED -OLD SHELL BOOKS

Will pay good prices for libraries second- 302--239-2025) or write: R. Tucker Abbott,

hand books and reprmts on mollusks, shells Amencnn Mahwohgist,. Inc.. P. 0. Box 4208.

and conchology. Back numbers of The NauU- Greenville. DE 19807. Free appraisals.
lus. vols. 40-71 wanted, $1.50 each. Phone (1-

PUBLICATIONS RECEIVED

Houbrick, Richard. S. 1978 (Dec. 15). The Family Centhiidae
in the Indo-Pacific. Part 1: The Genera Rhuuirlnri.%
Pseudovertagus and Clavocerithium. Monographs of Marine
Motlmca. No. 1. pp. 1-130. 98 pis. 3 in color. Taxonomic
revision, biologj'. anatomy, phylogeny and geographical
distribution of 47 living and fossil species. American
Malacologists. Inc. $17..50, postage paid.

Chatfield. .June E. 1978. Welsh Sea-fhells. 44 pp.. 90 figs. (20 in
color. Paperback. National Maseum of Wales. Cathays Park.
Cardiff. U.K. CFl 3NP. Remit U.S. $.3.00 or jC 1..50 sterling. An
e.xcellent little guide with 90 common shore species.

Goryachen. V. N. 1978. Gastropod Mollusks of the genus Sep-
tunea Rciding of the Bering Sea. 90 pp.. 25 pis. Science
Press, Moscow (in Russian).

The Pariah, no. 4. Sept. 1978. Edited by Jerr>' C. Walls. 8 pp.
Contains review of Harpidae (.J. G. Walls), note on Cin>raea
thoninsi (P. W. Clover) and remarks on Conns patae (J. G.
Walls). Available for 50 cents. P.O. Box 42. Hightstown. N.J.
08520.

Popenoe. W. P. and R. M. Kleinpell. 1978. Age and
Stratigraphic Significance fur Lyellian Correlation of the
Fauna of the Vigo Formation. Luzon. Philippines. Occ.
Papers California Acad. Sci.. no. 129. pp. 1-173. 18 pis.. 1
Uble.

Saul. Louella R. 1978. The North Pacific Cretaceous Trigoniid
Genus Yaadia. Univ. Calif. Publ. in Geol. Sci.. vol. 119: 1-65,
12 pis. $7.25. Excellent account.

Zhengzhi. Dcjug. 1976. On Three New Species of the Genus Oc-
topus from the Chinese Waters. Studia Marina Sinica, no.
11. pp. 211-215. (0. nanhaiensis, 0. striolatus and 0.
yuanydongensis new species).

Zhengzhi. Doug. 1978. On the Geographical Distribution of the
Cephalopods in the Chinese Waters. Oceanologia et Lim-
nologia Sinica. vol. 9, no. 1. pp. 108-116.

Wu, Shi-Kuei and Nancy Brandauer. 1978. Natural History
Inventory of CoUirado. 2. The Bivalvia of Colorado. Univ.
Colorado Museum. Boulder. CO 80.309. 60 pp. 87 figs., keys.

Giese, Arthur C. and John S. Pease, (editors). 1977. Reproduc-
tion of Marine Invertebrates. Vol. 4. Molluscs: Gastropods
and Cephalopods. 369 pp. Academic Press. HI Fifth Ave..
N.Y.. NY 10003. Hardback. .$38.00. An excellent, well-
illustrated and w^ell-documented account by competent
workers- Includes recent reviews of reproduction on Pro-
sobranchia (H. H. Webber). Opisthobranchia (R. D.
Beeman); estuarine Basommatophora (A. J. Berry);
Nautilus (Norine Haven); Squids (J. M. Arnold and L D.
Williams-.^mold): and Octopoda (M. J. and J. Wells).

NEWS

A.M.r. - W.S.M.. Joint Mpptiivj
Symposium on the Life Histories of Mollusks

Papers on any aspect of molluscan life histories
will be considered for presentation at a sym-
posium to be held during the joint meeting of the
Western Society of Malacologists and the Amer-
ican Malacological Union in Corpus Christi,
Texas, 5-11 August 1979. Presentations should
be concerned with an aspect of the reproduction,
development, growth, or population dynamics of
mollusks. Theoretical papers on the evolution of
life history traits of mollusks are also invited.
Opportunity for publication of abstracts or full
length versions of papers pre.sented at the sym-
posium will be provided. Further information
and a Call for Papers is available from:

David R. Lindberg

Invertebrate Zoology

California Academy of Sciences

Crt)lden Gate Park

San Francisco, CA 94 118

UNITAS MALACOLOGICA

The international society of professional
malacologists (formerly the Unitas Malacologica
Europaea) is now open to all scientists interested
in living or fossil mollusks. The President is Dr.
Jean M. Gaillard. Museum d'Histoire Naturelle,
55 rue de Buffon, F-75005 Paris, France, to whom
readers should write concerning the next and
Seventh International Malacological Congress.
Tliese meetings will be held August 31 (registra-
tion) to September 6, 1980, on the Mediterranean
coast of France near the "Laboratoire Arago".
Secretary of the Unitas Malacologica is Dr.
Oliver E. Paget, Naturhistorisches Museum,
Burgring 7, A-1014 Vienna, Austria.

Vol. 93(1) Januaty lU, 1979 THE NAUTILUS 1

SIX NEW LIVING SPECIES OF MURICACEAN GASTROPODS

William K. Emerson

American Museum of Natural History
New York, N. Y. 10024

and

Anthony D'Attilio

Natural History Museum
San Diego, California 90112

ABSTRACT

The following neiv species of gastropods referable to the Muricidae are
described: Pteropurpura benderskyi from West Afiica: Favartia guamensis and F.
dorothyae//'o»( the western Pacific, and F. elatensis/n*m the Red Sea: Murexiella
mactanensis from the we^em Pacific; and Siphonochelus radwini from the
western Atlantic. A recently described species. Murexiella martini Shikama, 1977,
from the western Pacific, is illustrated and a supplementary description is given.
Dermomurex neglecta (Habe and Kosuge, 1971), from the western Pacific, is il-
hi.sf rated and a tran.slation of the original description is provided.

At the time George E. Radwin and the junior
author were preparing the text for "Murex Shells
of the World, An Illustrated Guide to the
Muricidae" (Radwin and D'Attilio, 1976), a
number of taxa were recognized by them as new
species. Fifteen of these species were described in
an appendix to their book. Although they in-
tended to describe elsewhere several other taxa
that were received after the text of the book was
completed in mid-1971, the tragic and untimely
death of Dr. Radwin in 1977 terminated their
joint venture.

At the request of the junior author, the senior
author has joined him in the preparation of the
present report, which was based in part on
preliminary notes prepared jointly by D'Attilio
and Radwin for two of the taxa described herein.
The new taxa are classified largely according to
the system followed by Radwin and D'Attilio
(1976).

ACKNOWLEDGMENTS

We are grateful to the following collectors for
the loan and/or donation of specimens: Israel
Bendersky, L. J. Bibbey, Albert E. Deynzer,
Francis Fernandez, Dorothy and Robert
Janowsky, Leo Kempczenski, Don Pisor, and
Eugenia Wright. Dr. Joseph Rosewater of the
Department of Invertebrate Zoologv', National
Museum of Natural History, Smithsonian Institu-
tion and Dr. H. K. Mienis of the Zoological
Museum, Hebrew University of Jerusalem lent

additional material. Dr. Emily H. Yokes of the
Department of Geology, Tulane University, pro-
vided data and the photographs used to illustrate
figures 17 and 18. Masao Tabakotani of Bronx-
ville. New York, generously contributed a
translation of Japanese te.xt. William E. Old, Jr.
and G. Robert Adlington of the American
Museum of Natural History kindly provided
respectively, technical assistance and the
photography.

INSTITUTIONAL ABBREVIATIONS:

AMNH = American Museum of Natural History,

New York, New York
HUJ =Zoological Museum. Hebrew University of

Jerusalem, Israel
NMNH = National Museum of Natural History,

Washington, D.C.
SDMNH =San Diego Museum of Natural

History, San Diego, California

Family Muricidae

Subfamily Muricinae

Genus Deimomurex Monterosato, 1890

Type species: Murex scalarinus Bivona-Bemardi , 1832

( = M. xcalaroides Blainville, 1829), by original designation.

Dermomurex neglecta (Habe and Kosuge, 1971)

Figs. 17. 1,^

"Description: Shell distinguished by its varices,
five in number, in each whorl. They are broad
and somewhat prosocline at the shoulder to

2 THE NAUTILUS

January 10, 1979

Vol. 93(1)

suture position. Whorls between varices are
sculptured by numerous fine spiral striae so that
it looks almost smooth. Siphonal fasciole is
outstanding and umbilicus is open. Shell white
with slight yellowish tinge in color."

"This species is distinguished for the shape and
varices. Actually two specimens are known, both
caught in South China Sea and brought back to
the port of Kaohsiung, Taiwan." (Translation of
the Japanese text, courtesy of M. Tabakotani .)

Meaaurementu: Holotype, length 22.5 mm,
width 11.2 mm; specimen illustrated herein,
length 20 mm, width ll.(X) mm. (Wright collec-
tion).

Type locality: "South China Sea", fide Habe
and Kosuge (1971, page 7). Here restricted to off
Bohol Island, Philippines.

Material examined: 1 specimen, off Balicason,
Bohol Island, Philippines, in 366 meters, Eugenia
Wi'ight collection.

Remarks: At the suggestion of Dr. Emily H.
Yokes, we have presented here a translation of
the description of this poorly known western
Pacific taxon, together with photographs of a
specimen from the Philippines (figures 17, 18),
which along with another one, had been sent to
her for identification. Although this species was
originally described as Phyllocoma neylecta by
Habe and Kosuge (1971, p. 7, text figure), it is
referable to the genus Dermomurex and is the
first Recent record of the genus (sennu i^trirto) in
the Indo-Pacific. Yokes (1975, p. 129) cited this
record based on the Philippine specimens which
were thought to represent an undescribed species.
She pointed out (1975, op. cit.) that the specimens
lack apertural denticulations on the outer lip, in
contrast to the previously known representatives
of Dermomurex (i^emu stricto). According to Dr.
Yokes (in litt.) the present species is a probable
descendent of Dermomurex arutirostatii^ (Wanner
and Hahn, 1935, p. 254, pi. 19, figs. 8-10) from the
Miocene of Java.

Subfamily Ocenebrinae
Genus Pteropurpura Joussenume, 1880
Type species: Murex macroptents Deshayes, 1839, by original
designation.

Pteropurpura benderskyi, n. sp.

Figs. 1.2.19

Des^ciiptioii: Shell small for genus, attaining 23
mm. in length, trigonally fusiform in appearance.
Spire acute and high, with l'/2 polished, brown
nuclear whorls, followed by 5 convex, postnuclear
whorls; suture distinct, not strongly impressed.
Body whorl moderate in size. Aperture ovate,
with peristome entire and mostly erect, except
for the posterior portion of left side in the
parietal region. Siphonal canal broad, sealed (ex-
cept at the recurved, tapering distal end),
moderate in length and accommodating the siphon-
al fasciole. Body whorl with three winged varices;
each varix with webbing between prominent
spine-points. A medial costate ridge and two less
prominent flanking costae intervene between
each pair of consecutive varices. Spiral sculpture
of numerous primary and secondary cords ex-
tending over body and siphonal canal. Primary
cords strongest on dorsal surfaces of the spines.
Spine at shoulder margin longest; body with a
less prominent spine medially placed and with a
minor spine at the base of body whorl and on the
upper portion of siphonal canal. Leading, or ven-
tral sides, of varical spines weakly open; last
varix with leading edge sculptured with fine, low
undulating lamellae and with some grovrth lines
raised at intervals to give a somewhat scabrous
texture to the surface. Shell tan to dark-brown,
paler on the varical surfaces; aperture off-white
and porcelaneous. Operculum: The morphology is
typically ocenebrinean, as described by Radwin
andD'Attilio(1976,p. 111).

Radula: Radular dentition is similar in morph-
ological characters to those of the type species of
Pteropurpura, P. macroptera (Deshayes, 1839);
consult the radular illustrations of the Deshayes'
taxon (Rjidwin and D'Attilio, 1976, p. 131, fig. 81)
with the basal and frontal views of a rachidian
and a frontal view of a lateral tooth of the pre-
sent species (figure 19 herein).

Measurements: Holotype, length 23 mm, width,
including varices 13.9 mm; smallest paratype (SD
MNH no. 72626). 17.7 mm in length.

FIGS. 1 and 2, Pteropurpura bendersl<yi n. up., holotmw. AMNH lK.iHl9. X.l 3 and 4, Favartia dorothyae n. sp.. holotype. AMNH
183821. X.l. 5 and 6, Favartia rosea Hahe. 1.961. .Janowsky CDllection. tmirled in Kii Channel. Wnkayama Prefecture. .Japan, in U6
meters. X.l. 7 mid 8, Favartia mactanensis n. sp.. holotype. AMNH 1871H6. X.l. 9 and 10, Murexiella martini Shikama, 1977, SDMNH
72627, Bohol Islattd, Philippines, X2. (Stated enlargements are an appronmalion)

Vol. 93(1)

January 10. 1979

THE NAUTILUS 3

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January 10, 1979

Vol. 93(1)

Tif})c lornlity: Off Luanda, Angola, Africa,
dredged in 5<l meters, sandy bottom, July 15, 1977,
FYancis Fernandez collector.

Material examined: Holotype AMNH 183819,
from type locality, 1 paratype SDMNH 72626, ex
Bendersky collection, and 1 paratype, Janowsky
collection, hnjth from off Luanda, Angola, dredged
in 80 meters, February 10, 1977.

Remarks: Until the discovery of this new-
species, only one living representative of this
genus was knovra to occur in the Atlantic Ocean.
Ihe other living Pteropurpura are found in the
northern Pacific, with three in northwestern
waters (largely off southeastern Japan) and with
five in northeastern waters off California and
northwestern Me.xico (see Radwin and D'Attilio,
1976, pp. 129 to 133). The present species (figures

1. 2) differs from P. bequaeni (Clench and Pe'rez
Farfante, pi. 21, figs. 1, 2, 1945), which ranges
from North Carolina to the Dry Tortugas, in
several characteristics (see comparative data in
table 1). The two taxa clearly represent twin
species, or cognates, separated by the present ex-
panse of deep water of the Atlantic Basin.

Subfamily Muricopsinae
Genus Faimiia Jousseaume, 1880
Type species: Murei breinculus Sowerby. 18.34. by nripinal
de.signation.

Favartia guatnensis n. .sp.
Fips. 11.12

Drxcription: Shell small, attaining 8 mm in
length, fusiform. Characterized by strong rugose

FIGS. 11 (!/»/ 12, Favartia guamensi.s n. up., halnti/pe. SDMXII ;av.5. X.r l.S ami 14, Favartia elatensis >i. sp.. pamtifpe.
SDMNH 6M5ia. X.5. 15 and 16, Favartia dorothyae n. .fp.. parati/pc- AMNH lS^i82:i. X.i. 17 and 18, Dermomurex neglecta

(Hahe and Koxntir. 1!)7II: Wnnht culU'ctiiDi. (iffBulml Island. Philippines. XJ. (Stated rnlniyrnii-nts art' an apprariniatitin)

Vol. 93(1)

January 10, 1979

THE NAUTILUS

TABLE 1. Comparative diagnostic charm-ters of Pteropurpura bequaerti and Pt. benderskyi

Pteropurpura bequaerti

Maximum size 42 mm

Numbers of whorls 6 to 7

Outer lip crenulated

Varices blade-like

Axial sculpture a single, low knob

Spiral sculpture terminates in toothlike points on varical

margins

Color gray-white; tip of siphonal canal suffused

with purple-brown.

sculpture. Protoconch low, smooth with IVz
whorls; followed by 5 convex whorls; suture deep
but obscured at varices; spire well elevated.
Aperture ovate; peristome weakly erect; anal
sulcus deep, constricted in front into a closed
channel. Siphonal canal with rostrate fasciole,
broader above, tapering distally, slightly recurved
with a narrow sinuous opening. Shell with 5
strong, spiral cords, squarish in cross-section and
with an additional cord on the canal; cords
crossed by strongly elevated fimbriae; fimbria-
tions extend into the interspaces. Spiral cords
with a strong central groove, crossed by fine
lines, and with fimbriae forming strong, canopy-
like scales; scales further interrupted axially by 5
to 8 fine grooves; scales scalloped on terminal
edge. Varical flanges elevated and terminally
wavy; early whorls with 6 varices; body whorl
with 4 varices. Color of shell deep orange-red,
ranging to yellow in the four specimens ex-
amined.

Measurements: Holotype, 7.5 mm in length;
largest paratype, 7.7 mm in length; smallest
paratype, 6.6 mm (Pisor collection).

Type locality: Off Orote Cliffs, Guam, Marianas
Islands, in 18 to 21 meters under large boulders,
5-1-1977, Leo Kempczenski collector.

Material examined: Holotype, SDMNH no.
72625; 1 paratype, Leo Kempczenski collection
and 1 paratype, AMNH no. 183820, all collected
by Leo Kempczenski from type locality; 1
paratype from type locality, Don Pisor collection;

Pt. benderskyi. n. sp.

23 mm

5 (or more ?)

not noticeably crenulated

spine-like projections

medial costae and 2 less prominent flanking costae.

varical margins extended into 4 broad-based, spiny
terminations, with scabrous lamellae on ventral sur-
face.

tan to dark-brown, paler on ventral surface

1 paratype from coral rubble, in 18 meters, SCUBA
diving, 1977, A. Deynzer collection.

Remarks: The small size of the present species
(figures 11, 12), complemented by the develop-
ment of elaborate sculpture, the elongated body,
and the rich coloring serve to distinguish this
taxon from any of its congeners.

Favartia dorothyae, n. sp.

Figs. 3. 4. 15,16

Description: Shell small for genus, attaining 9
mm in length, broadly fusiform; spire elevated
but small in proportion to body whorl; pro-
toconch of l'/2 whorls; post-nuclear whorls 6 in
number; suture distinct. Body whorl obese, with
a small ovate aperture; anal sulcus weakly-
developed. Lower half of inner lip erect, adherent
above; outer lip crenulated and sculptured within
by 7 long lirae. Anterior end of columella or-
namented by a small tooth. Siphonal canal broad
above, tapering and distally recurved; siphonal
fasciole rostrate. Body whorl with 5 major cords
and with one major cord on canal; each cord sub-
divided by 4 or 5 incised lines. Three secondary
cords situated above the major cord at shoulder.
A secondary cord present on the body whorl
below the second and third cords. A major cord
appears on the canal with secondary cords above
and below it. Additional minor spiral cords pre-
sent on the body as well as over the shoulder.
Five varices form the axial sculpture. Starting at

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January 10. 1979

Vol. 93(1)

each varical margin, the cords ascend to the
strongly developed varix where they terminate
and are recurved distally. The leading side of
each varix bears 7 or 8 fimbriae which develop
into scaly sculpture over the whorls. The shell
color ranging from warm-white to carmine with
the early whorls golden-hued; characteristically
with the cx)lumella, the dorsal and ventral sides
of the canal, and the base of the body whorl are
all strongly colored a rosy pink.

Measurements: Holotype 15.9 mm in length,
width 9.6 mm; smallest paratype (lacking a
mature siphonal canal) 13.7 mm (AMNH 183822);
largest paratype, 16.2 mm (SDMNH no. 72624).

Ti/pe locality: Off Punta Engano, Mactan
Island, Philippines, in about 30 meters, (obtained
in tangle or gill nets), 1977, ex Dorothy and
Robert Janowsky collection.

Material examined: Holotype AMNH 183821
(figures 3, 4), and three paratypes AMNH 183822, 1
paratype SDMNH 72624 (figures 15, 16, AMNH
183822a); 3 paratypes, Janowsky collection; 1
paratype Leo Kempczenski collection ; all from the
type locality. Three specimens, Panglao, Bohol
Island, Philippines, in trap, 1977-1978, A. Deynzer
collection.

Remarks: This species (figures 3, 4, 15, 16) with
its distinct apertural coloration and delicate
frostlike sculpture may be easily distinguished
from the following congeners: F. marjorae
(Melvill and Standen, 1903), to which it bears
some resemblance, by comparison with a
photograph of the holotype in Radwin and D'At-
tilio, 1976, fig. 95, p. 150. F. marjorae, which has
a less swollen body and a higher spire, is grey in
color and occurs in the Persian Gulf. F. balteata
(Sowerby, 1841) from the western Pacific has a
more strongly sculptured shell, with well-
developed black squarrose varices, and has a
brown shell with a red aperture. F. salmonea
(Melvill and Standen, 1899) has a comparatively
higher spire, possesses a decided gap between the
body cords and those on the canal, and is pale
reddish orange, darkest at the varices. It has not
been reported from the northern area of the
western Pacific. F roaea Habe, 1961, (herein il-
lustrated, figures 5, 6), from southeastern Japan,
has a larger (23 mm), fleshy orange to yellow col-

ored shell, with the varical areas conspicuously
more rounded (swollen), and the surface not
noticeably scabrous.

Favartia elatensis n. sp.

Figs, la u

Description: Shell small for genus, attaining 8
mm in length, fusiform; spire high; protoconch
1'-: rounded whorls, followed by 5 post -nuclear
whorls; suture distinct. Aperture ovate, outer lip
strongly undulate reflecting the dorsal sculpture;
inner lip adherent; anal sulcus broad and simple;
canal moderately long, narrowly open, tapering,
weakly recurved, siphonal fasciole moderately
developed. Axial sculpture strong with growth
lines developing into widely spaced lamellae;
vaulted scales formed by expansion of lamellae
over the spiral cords. Six varices on post-nuclear
whorls of spire; four on body whorl. Varices
crossing at shoulder diagonally onto contiguous
whorl. Spiral sculpture of 6 squarish and knobby
cords on body whorl, with one cord, on the canal;
cords grooved spirally, but dividing somewhat ir-
regularly into unequal widths, to form unequal
scaly ornamentation. Cords at the varical
margins expanded into lobes; final varix with a
recurved margin. Varical areas of shoulder ex-
tending into lobes with vaulted edge on leading
side. Shell color uniformly fleshy white.

Measurements: Holotype 7.8 mm in length, 3.9
mm in width; largest paratype, 7.9 mm in length
(SDMNH no. 63254a, figures 14, 15); smallest
paratype (immature) 4.2 mm (HUJ no. 10.202/8).

Tt/])e locality: Elat, Gulf of Elat, Israel,
29°32'-29°31' N., 36°58'-36°59' E., in 190
meters from grab sample, October 8, 1965.

Material examined: Holotype and 7 paratypes
HUJ 10.202/8 fix)m the type locality; 2 paratypes
SDMNH 63254, ex HUJ 10.202/RS-18, Elat, Gulf of
Elat, 29°32'-29°31' N., 36°58'-36°59' E., in 190
meters; 1 paratype AMNH 183823, ex HUJ
10.204/1. Elat, Gulf of Elat. 29°31'-29°32' N..
34°58'-36°59' E., in 250 meters, October 8, 1965; 8
paratypes, HUJ 10.203/9 Elat, Gulf of Elat,
29°3r-29°32' N., ;34°58'-34°59' E., in 80 meters.

Remarks: The presence of squarely-formed
spiral cords terminating in lobed projections, and
the relatively small size of the shell (figures 13,

Vol. 93 (1)

January 10. 1979

THE NAUTILUS

14) serve to distinguish this species from others
in the genus. This species is presently knowTi only
from the Gulf of Elat. Although Recent Favartia
are not recorded in the Mediterranean, some
Indo-Pacific species with shells larger than that
of F. elatensis occur intertidally or in shallow
depths elsewhere in the Red Sea.

Genus Murexiella Clench and Farfante, 1945
Type species: Miirex hidalgoi Crosse. 1869. by original
designation.

Murexiella mactanensis n. sp.

Figs. 7. 8

Description: Shell medium-sized for genus, at-
taining 22 mm in length; biconically fusiform;
spire elevated, with 5 convex whorls; protoconch
dense white and with suture impressed. Aperture
broadly ovate; peristome erect, more weakly
elevated on the left posterior side; margin of
outer apertural lip wavy, with the 5 undulations
reflecting the presence of the external cords; anal
sulcus weak; si phonal canal moderately long, nar-
rowly open; tapering tube-like and strongly
recurved; siphonal fasciole strong, spaced some
distance from body sculpture. Axial sculpture of
5 erect varices terminating distally as open
spines of moderate height; final varix set-back
from aperture, bent back and with the leading
side richly scabrous; scabrous lamellae on leading
side of all varices to the margin of each varix: in-
tervarical area with weaker lamellae or with
lamellae developing into scales. Spire with 6
varices, the varices more weakly erect crossing
the shoulder diagonally and continuing on to the
varix of preceeding whorl. Body whorl with 5
spiral cords; cords nearly erect on varices and
temiinate as upturned spines. Spines at shoulder
longest; the first two paired, followed by the re-
maining 3; spines open, marginally not or-
namented and on the final varix broadest distally
with the edges recurved on the leading side;
spines subdivided lengthwise by incised lines into
2 or 3 unequal areas. Minor cords situated be-
tween large ones, with a gap between the last cord
on the body and the spinal cord on the canal.
Shoulders ornamented, notably on the final varix,
with a short lobe having 3 or 4 pointed spines.

Shell color: on the holotype, the spire, inter-
varical areas, and fasciole flesh-pink, darkest
towards the apex; varical areas white, especially
terminally: aperture white. In the paratypes, the
amount of the flesh-pink coloration varies in in-
tensity and location on the shells.

Memurements: Holotype 21.7 mm in length,
width (including spines) 14.3 mm; smallest
specimen (4 post -nuclear whorls; Pisor collection),
length 12.9 mm.

Type locality: Off Punta Engano, Mactan
Island, Philippines, in about 30 meters (obtained
in tangle or gill nets), 1977, ex Dorothy and
Robert Janowsky collection.

Material examined: Holotype AMNH no. 187186
(figures 7, 8); 1 paratype Panglao, Bohol Island,
Philippines, in about 180 meters, 1977, Albert
Deynzer collection; 1 paratype SDMNH 7:3800 (ex
Pi.sor collection) and 1 paratype Don Pisor collec-
tion, both Bohol Straits, Philippines, in about 50
meters.

Remarks: The present species, characterized by
having the 5 varices terminating in simple, unor-
namented spines, may be assigned to Murexiella
(sensu stricto), based on the typological genus-
group concept of Murexiella Clench and Pe'rez
Farfante, 1945 (see Radwin and D'Attilio, 1976, p.
155-161). Several western Pacific species were
assigned by Ponder (1972) to Murexiella. which
he regarded as a subgenus of Favartia. These
other taxa differ from the new species by their
closer relationship to Favartia (sensu stricto).
Comparison can be made with the Indo-Pacific
species F. salmonea (Melvill and Standen, 1899)
and F. voor-unndei Ponder, 1972, in which the
body whorl and sculpture are somewhat similar.
They lack, however, well -developed spines with
connecting webbing, characters that serve to
distinguish taxa referable to Murexiella (sensu
strict(i)- This new species, together with the one
following, brings to two the number of distinctive
Murexiella recognized recently in the central
Philippines.

Murexiella martini Shikama, 1977

Figs. 9, 10

Supplemental description: A slender fusiform
shell, attaining 28 mm in height (holotype); spire

8 THE NAUTILUS

January 10, 1979

Vol. 93(1)

19

FIG. 19. Pteropurpura benderskyi n. xp., radular dentition
(drawirigs by Anthony D'Attilio); greatly enlarged.

well -elevated, with a protoconch of 1"4 whorls,
followed by 6 post-nuclear whorls; body whorl
large, strongly spined at shoulder; suture im-
pressed. Aperture ovate, peristome entire and
strongly elevated; sulcus shallow and broad;
outer lip with 4 extended, lobe-like crenulations
reflecting the dorsal spiral sculpture. Siphonal
canal narrowly open, broad above, strongly
recurved, tapering axially and tube-like distally,
with fasciole formed by terminations of the two
previous canals. Body whorl with 3 spinose
varices; varical margins thick, erect and continu-
ing nearly midway to the intervarical area; basal
varix crossing the shoulder diagonally and ex-
tending to the previous whorl. Four strong spiral
cords, one at shoulder separated by a gap from
the group of 3 below; cords terminating in long
moderately open spines at the varices; spine at
the shoulder longest, those below about ' 2 as
long; cords subdivided by 3 to .5 incised lines.
Spines connected by a flangelike web ornamented
with a scabi-ous lamellate surface on the leading
side; varical webbing with one .small, medial cord
and with a weakly defined cord on either side of
the central cord. Scaly lamellae on entire surface
of the shell, exclusive of the canal, and with mo.st
prominent lamellar development on the raised
cords and .spines. Shell pale-brown ochre, lighter
dorsally on the cords and spines, darker brown
on the open inner surface of the cords and on the
varical margins; aperture and peristome translu-

cent whitish. Color somewhat variable among the
10 specimens examined.

Measurements: Largest specimen examined
26.6 mm in length, width (excluding spines) 9.5
mm; smallest specimen (lacking mature siphonal
canal) 18 mm in length, width (e.xcluding spines)
7.6 mm, Ribbey collection.

Type locality: Off C€bu Island, Philippines.

Type depository: Personal collection of Dr.
Tokio Shikama, Yokohama, Japan.

Material examined: Figured specimen SDMNH
no. 72627 (figures 9, 10) and 1 other specimen,
Bohol Island, Philippines, I.^o Kempczenski col-
lection; 3 specimens from off Punta Engano, Mac-
tan Island, Philippines Islands, Janowsky collec-
tion; 1 specimen, Mactan Channel, Philippines, in
tangle-trawl, Bibbey collection; 1 specimen
AMNH no. 183818, from Samar Island, Philip-
pines, ex Bibbey collection; 2 specimens, Panglao,
Bf)hol Island, Philippines, in trap, 1977-1978,
Deynzer collection.

Remarks: This distinctive western Pacific
species (Shikama, 1977, p. 1,5. pi. 2, figs. 10a, 10b)
is characterized by the relatively small size of the
body whorl, the slightly extended spire, the
lengthy spines, and prominent webbing (figures 9,
10). It was compared by Shikama (1977. p. 15) to
several unrelated long-spined species: Chicoreus
damicornis (Hedley, 1903), C. ojcicomis (Lamarck,
1822), and Murex lonyiconiiii Dunker, 1864.

SUBFA.MILYTv-phinae
Genus Siphonocheluii Jousseame, 1880
Type species: Tijphix areiiatiix [sic] Hinds. 1844 ( = 7*. ar-
cuatiis Hinds, 1843), by original designation.

Siphonochelus radwini n. sp.

Figs. 20, -jl

Description: Shell small for genus, attaining 5
mm (holotype immature, lacking perhaps one
body whorl), fusifomi; spire acute, of !'< bulbous
nuclear whorls, followed by 3 weakly angulate
ix)stnuclear whorls; suture impressed. Body whorl
lai'ge. fusoid; aperture small, ovate with an entire
and erect peristome. Anal sulcus apparently lack-
ing, but with a moderately long anal tube, arising
at the rounded, poorly defined margin of shoulder

Vol.iKHD

January 10, 1979

THE NAUTILUS

20

FIGS. 20 and 21, Siphonochelas radwini n. sp.. Iwluttjpe.
NMNH 323198 (drmdngs by Anthony D'Attilio); greatly
enlarged (mt II ml. tize = 5.0 mm. In length).

in each varical interspace, and more closely
placed to the earlier of the two varices. Proximal
portion of each tube on the body swollen and ax-
ially depressed on the left side below the shoulder
margin. A minor swelling produced on the lead-
ing side of each tube, terminating as a fold at the
margin of the shoulder. Distal portion of tubes
generally short, slanted, and irregular in cross-
section. Last tube largest, weakly bent to the
right, and the only one remaining open. Body
whorl with 4 varices: each varical margin with a
slight axial thickening corresponding to a former
outer apertural lip. With increasing whorl size,
position of each tube slightly ahead (in the direc-
tion of growth) of the corresponding tube on the
preceeding whorl. Siphonal canal broad, moder-
ately short, tapering, closed, bent to the right and
dorsally recurved. Shell dull-white; aperture
polished white.

Mea.'^urements: Holotype (figure 20, 21), length
5.0 mm, width 2.5 mm.

Tijpe locoUty: Off Cabo Catoche, Yucatan, Mex-
ico, dredged in 46 meters, USBF Sta. 2361.
Material studied: Holotype NMNH 323198.
Remarh: We have followed the genus-group
concept of Radwin and D'Attilio (1976, pp. 198-
200) in assigning this new species to Sipho-
nochdm. the first record of a living represen-
tative of this genus from the New World. Addi-
tional living species of Siphnnochelus are
recorded by these authors from the western
Pacific and from off the Cape of Good Hope. It
should be noted, however, that Radwin and D'At-
tilio (1976) rejected the previous assignment by
several authors of western Atlantic species to
Siphonnchehis (e.g.: Keen, 1944; Gertman, 1969;
and Bayer, 1971): see also Penna-Neme and Leme
(1978) for their use of Siphoriochelus for an
eastern American species.

Although this taxon is based on a unique, ap-
parently immature specimen, its distinctive
morphology, together with its occurrence in the
Western Hemisphere, has led us to describe it.

LITERATURE CITED

Bayer. F. M. 1971. Biological results of the Univereity of
Miami Deep-Sea Expedition 79. New and unusual moUusks
collected by R/V -John Elliot Pilhbury and RA^ Gerda in
the tropical western Atlantic. Bnll. Mar. Sri. 21(l):lll-236.
72 figs.

10 THE NAUTILUS

January 10. 1979

Vol. 93(1)

Bivona-Beraardi. A. IKfi. Caratteri di alcune specie de con-

chiglie, estratti come sopra. F^fem Sci. Lett. Sicitia 1 16-24.
Blainville, H. M. D. de. 1829. Fauna franpise ou histoire

naturelle, gene'rale, et particuliere des animaux qui

retrouve en France. Moilusques. Levraux, Paris 1-320. pis.

Ml,
Clench, W. .J., and 1. Pe'rez Farfante. 1945. The genus Murex

in the western .■Mlantic.MH.s-oHiVi 1(17):1-,t6, pis. 1-28.
Crosse. H. 1869. Diagnosis moiiuscorum novorum. Jmtrn. de

Coiichyl. n-.-m-iW.
De.shayes. G. P. 18.39. Nouvelles especes de moilusques. prove-

nant des c3tes de la Californie, du Mexique. du Kamt-

schatka et de la Nouvelle Zelande. d&rites par M.

Deshayes. Rev. Zool. Soc. Qmerierenne. 2:.356-61.
Dunker. W. 1864. Fiinf neue Mollusken. Malak. Bliitt.

11:99-102.
Gertman. R. 1969. Cenozoic Tj'phinae (Mollusca: Gastropoda)

of the western Atlantic region. Txlaiie Stud. Ceol. and

Meant. 7(4): 14.3-191, pis. 1-8.
Habe. T. 1961. Caloured illmtratians of the shelh < if -Japan

[vol. 2]. Hoikusha, Osaka. 183 p.. 66 pis.
Habe. T.. and S. Kosuge. 1971. Pacific Shell News. Tokyo.

Japan. (3):7. (Published on October 30, 1971).
Hedley. C. 190.3. Scientific results of the trawling expedition

of H. M. C. S. Thetis off the coast of New South Wales in

Feb. and Mar., 1898, pt. 6. Mem. Australian Mus.

4(l):.326-402, pis. 36-38. figs. 61-1 13.
Hinds, R. B. 1843. On new species of shells collected by Sir

Edward Belcher. C. B. Proc. Zool Soc. London, for 1843.

11: 17-19 (July. 1843).
1844. The zoology of the voyage of H. M. S.

Sidphur. London. Mollusca, pt. 1, 1-^4, pis. 1-7 (July, 1844).
Jousseaimie, F. 1880. Division methodique de la famille des

Purpurides. Le Naturaliste,42:.3a5-336.
Keen, A. M. 1944. Catalogue and revision of the gastropod

subfamily Typhinae. Jour. Pcdeont. 18(l):.50-72. 20 figs.

I^niarck. J. B. P. A. 1822. Hittoire naturelle des animaux

.sfiH.s veiiebrex. Paris. 7, 232 pp.
Melvill. J. C. and R. Standen. 1899. Report on the marine

Mollusca obtained during the first expedition of Prof. A. C.

Haddon to the Torres Straits in 1888-1889. Jour. Linn. Soc.

London. 27:1.50-206. pis. 1, 2.
190.3. Descriptions of 68 new Gastropoda from the

Persian Gulf. Gulf of Oman and N. .Arabian Sea dredged by

Mr. F. W. Townsend of the Indo-European Telegraph Svc.

1901-190,3. .4«n.A/as.A'a/. Hist. 12:289-.324. pis. 20-23.
Monterosato, T. A. di. 1890. Conchiglie della profundita del

mare di Palermo. A^a<. Sicil. 9:140, 1.51, 157-66, 181-91.
Penna-Neme, L., and J. L. Moreira Leme. 1978. Novas especies

e novas ooorrencias de gastropodos marinhos na costa

Brsisileira. Pap. Avidsos Zool, SSb Paulo 31(18):283-297, 33

figs.
Ponder, W. F. 1972, Notes on some Australian genera and

species of the family Muricidae (Neogastropoda). Jour.

Malac. Soc. Austral. 2(3):215-248.
Radwin. G, E.. and A. D'Attilio. 1976. Murex Shells of the

World, an illastrated guide to the Muricidae. Stanford

Univ. Press. 284 p.. 32 pis.. 198 text figs.
Shikama. T. 1977. Descriptions of new and noteworthy

Giistropoda from western Pacific and Indian Oceans. Set.

Reixiiis, Yokohoma Natl. Univ.. sect. 2. Biol, and Geol. Sci.,

no. 24:9-23. pis. 1-5. 2 figs.
Sowerby, G. B. II. 1834. The conchological illustrations, Murex.

London, pis. .58-67.

1841. Ibid., pis. 187-189, and catalogue, p. 1-9

Yokes, Emily H. 1975. Cenozoic Muricidae of the western

Atlantic r^ion. Pt. 6, Aspella and Dermomurex. Tiilane

Stud. Geol and Paleont. 11(3): 121-162, pis. 1-7.
Wanner. J. and E. Hahn. 193.5 Miocane Mollusken aus der

Liindschafe Rembang (Java). Zeitsch. Deutsch. Geol Gesell.

Berlin 87(4):222-273, pis. 17-21.

SCAPHELLA CONTOYENSIS,
A NEW VOLUTID (GASTROPODA) FROM EAST MEXICO

William K. Emerson

and

William E. Old. Jr.

Department of Invertebrates

American Museum of Natural History

New York. N. Y. UX)24

ABSTRACT

Scaphella contoyensis, a new species from the Yucatan Channel, Mexico, is
desciibed and compared urith related volutid species of the New World subfamily
Scaphellinae.

During the past decade, several examples of a
large, thin-shelled volute have been obtained by
shrimpers in depths ranging from about 70 to 180

meters in the Yucatan Channel, mostly in the
vicinity of Contoy Light, off Cabo Catoche,
Yucatan, Mexico. These specimens are somewhat

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 11

reminiscent of Australian species of Ericusa and
Cymhiolista in size and coloration, but they lack
the spinose ornamentation that characterizes the
latter Indo-Pacific forms.

Specimens of the new species were generously
donated to us by Donna and Riley Black and
Elsie Malone of Ft. Myers, Florida, and Dr.
William J. Clench of Dorchester, Massachusetts.
Gene Everson of Ft. Lauderdale, Florida, kindly
lent a specimen from his collection and donated
the soft parts. These specimens fonu the basis for
the present report. Additional specimens, all
taken by dredging in the Yucatan Channel, are
preserved in the following private collections:
Christine S. Goddard of Ft. Myers Beach, Florida,
1 specimen, in 46 meters, March 1968. Barbara
and Thomas McGinn of Cutoff, Louisiana, 8
specimens (2 of which are now in the collection of
the American Museum of Natural History), in
132 to 183 meters, February 1970, (1 specimen),
March, 1972 (6 specimens), 1975 (1 specimen);
Elsie Malone of Ft. Myers, Florida, 1 specimen in
90 meters, ex Carmel and Wassy Frank collection;
Carmel and Wassy Frank, Ft. Myers, Florida, 2
specimens (teste Elsie Malone); and Ernie
Ryckman, of Key West, Florida, 1 specimen. We
are grateful to these collectors for providing data
and photographs of their specimens.

Drs. Frederick M. Bayer and Joseph Rosewater
of the National Museum of Natural History also
contributed data, and the latter lent us the
holot>T3ic specimen of Scaphella evelina Bayer.
Our colleague, G. Robert Adlington, photographed
the specimens illustrated in this paper.

TAXONOMIC PLACEMENT

Bayer (1971, pp. 200-221) succintly reviewed the
pertinent literature pertaining to the classifica-
tion of the western Atlantic species of Volutidae
[q.v., Clench, 1946, 1953; Clench and Turner, 1964,
1970; Olsson, 1965; Pilsbry and Olsson, 1953, 1954,
and Weaver and duPont, 1970). We concur with
Bayer's conclusion that the classification of the
family is ". . . still a difficult matter," as the
genus-group assignment of the Scaphella
described herein proved to be perplexing because
of conflicting data. We must, however, comment
on Bayer's (1971, p. 195) placement of the genus

Teramarhia Kuroda, 1931, in the family Tur-
binellidae, based largely on shell characters in
the absence to him of information on the radula.
Anthony D'Attilio (in litt.) has pointed out to us
that the radular characters of T. tlbiaefonnis
Kuroda, 1931, the type species of Teramachia, as
illustrated by Habe (1952, p. 132, fig. 12), are
typically volutid. This genus is, therefore,
referable to the subfamily Calliotectinae Pilsbry
and Olsson, 1954, on the basis of radular and
opercular morphology (v. et.. Weaver and duPont;
1970, p. 177, fig. 41b, for an illustration of the
operculum).

In the most recent reviews of the subfamily
Scaphellinae, Bayer (1971, pp. 209-216) and
Weaver and duPont (1970, pp. 140-145) recog-
nized the genus Scaphella as a polytypic taxon to
include, in addition to the nominate subgenus,
the subgenera: Qenchina. Pilsbry and Olsson,
1953 (type species by original designation: Voliita
dohrni Sowerby, 1903, = S. govMiana (Dall,
1887), fide Abbott, 1974, p. 244) and Aurinia H.
and A. Adams, 1853 (type species by original
designation: Volutia dubia Broderip, 1827). The
subgeneric units were separated by these authors
largely on the basis of minor differences in the
radular morphology, as defined by Pilsbry and
Olsson (1954) in their "Systems of the Volutidae".
According to Bayer (1971, p. 209, and fig. 63), the
t.vpe species of Scaphella (sensu strkto), Voluta
junonia Lamarck, 1804, has ". . .a single long,
concave cusp and no small basal denticles."; S.
(Clenchina) dohrni has "... a shorter, more
pointed, concave cusp flanked by minute acces-
sory cusps."; and S (Aurinia) dubia, together
with the genus Volutifusus Conrad, 1863, has
". . .a well -developed lateral cusp on each side of
the main, central cusp." Bayer concluded that the
simple Y-shaped teeth of S. junonia had resulted
from progressive reduction of the side-denticles
from the well-developed tricuspid teeth of Au-
rinia and he suggested that these distinctions
would be found to be of minor taxonomic sig-
nificance, when more radular data became
known. The radular morphology of the new spe-
cies of Scaphella described herein serves to sup-
port Bayer's thesis, because the teeth lack basal
denticles (fig. 7), in contrast to the denticled
teeth of S. evelina Bayer (1971, fig. 63), which we

12 THE NAUTILUS

January 10, 1979

Vol.93 (1)

believe tx) be the closest known relative of S!
nint(iye))!iis, n. sp. (see remarks below).

In addition to the supposed radular differences,
Scaphella (sensu stricto) and Scaphella (Clen-
china) have been distinpuished by trivial con-
cholopical characters, including the possession by
the latter of less-solid shells than those of S.
junonki (Weaver and duPont, 1970, p. 140). The
basic similarity of the shell morphology, together
with the minor differences of the radular
characters, however, suggests to us that the
genus-group taxon Genchim is of questionable
taxonomic value and our new species, together
with S. eveiina, should be assigned to Scaphella
(sensu stncto).

Family Volutidae

Subfamily Scaphellinae

Genus Scaphella Swainson, 1832

Type species: Valuta jmumia Lamarck. 1804, by subseciuent
designation. Herrmannsen. 1848, p. 423.

Scaphella contoyensis, n. sp.

Figures 1 -7

Description: Shell fusiform, large (attaining
170+ mm in length), with 6 whorls. Protoconch
large and .smooth, consisting of about 2 whorls.
The first three post-nuclear whorls are thicker
and more solid than the fragile body whorl,
which is thin and inflated in mature individuals.
The first 2 post-nuclear whorls sculptured with
fine intersecting spiral and axial cords that give
a weakly cancellate appearance to the surface
(figure 5). Surface sculpture of the third post-
nuclear whorl, especially posteriorly near the
suture, is microscopically cancellate, but the
sculpture is scarcely perceptible and the surface
becomes macroscopically smooth on the body
whorl. Spire short, not acutely angled; .suture
well-defined, moderately impressed. Aperture
elongate-elliptical; outer lip thin and the parietal
wall thinly glazed. Anal sulcus narrow and con-
stricted [wsteriorly; .si phonal canal broadly ex-
tended. Columella slightly arched, with two plica-
tions extending within the aperture. Periostra-
cum tannish yellow and exceedingly thin.

Color of nuclear whorls is uniformly tanni.sh
brown; ground color of second and third po.st-
nuclear whorls buff, overlaid with two spiral

rows of irregular, elongated, chestnut-brown
spots; ground color of third post-nuclear whorl
and body whorl is a darker buff, with in-
terspersed spiral bands of chestnut-browTi streaks,
which are lighter than the earlier chestnut-brown
spots. In mature specimens, the interior edge of
the outer lip (figure 3) has a c-ontinuous band of
dark brown and the aperture is glossy, tannish-
yellow to apricot.

Softpaiis: Length of foot, after preservation in
alcohol, 78 mm; color-base whitish, with irregular
dark markings that are preserved as black
blotches (figure 6). Radula: Reduced to simple Y-
shaped rachidian teeth lacking basal denticles
(figure 7). An operculum is lacking.

Measurements: Holotype 173 mm in length,
67.3 mm in width; figured male paratype, length,
70 mm in width (Everson collection); smallest
specimen, immature, with three post-nuclear
whorls, 56.5 mm in length (McGinn collection).
Slender female specimen, 166 mm in length, 58.5
mm in width (AMNH collection, ex McGinn and
Clench).

Tiipr liKvlity: Northwe.st of Contoy Light,
Yucatan Channel, Mexico, dredged in 159 meters,
September 1973, by Donna and Riley Black.

Ti/pe specimens: Holotype, AMNH 187180
(figures 1, 2, 5); paratype (figures 3, 4), north-
west of Contoy Light, off Yucatan, Mexico,
dredged in 73 meters, March 1978, Gene Everson
collection. Paratype AMNH 182250, trawled off
Punta Francisca, Yucatan, Mexico, in 183 meters,
March 1972, ex McGinn collection.

Kmnrn range: Yucatan Channel, off Cabo
Catoche, in 73 to 160 meters, and off Punta Fran-
cisca, in 183 meters, Yucatan, Mexico.

Remarks: Scaphella contoyensis n. sp. appears
to be most closely related to Scaphella rrrlina
Bayer (1971, p. 213-216, figs. 63c, 64), a species
described from off eastern Panama and Colombia,
in depths of 137 to 641 meters. Bayer's taxon
diffei's from the present species by the i>).s.session
of an acute spire, in the development of much
stronger cancellate .sculpture and a less fiaring
outer lip, and by the pre.sence of a less distinctive
and apparently inconsistent color pattern, as well
as by the radular characters discussed abive.

Vol. 93(1)

January 10. 1979

THE NAUTILUS 13

FIGS. 1-6 Scaphella rontoyensis n. sp. 1, 2 hjUdtnu. AMXH lH7im. X'A: 1, Apetliiral vieu; note immature outer lip: 2, Dfrrsal
i'iev. 3, 4, Paratifpe. Erersim collection. .Y' ?; 3, Apetiural i-ieic. note mature outer lip uith dark colored hand on interim- edge of
the outer lip: 4, Dorsal vieu: 5, Enlargement of the apical region if the holotijpe. showing weak cancellate sculpture. X2. 6, Body
oftheparatype specimen illustrated in figs. 2, 3, X'l: soft parts contracted hijpre.'^erration in alcohol and sans the liver

The development of cancellate sculpture in this
subfamily varies considerably among the species-
group taxa and within some populations of these
taxa. Of the extinct species that are most closely
related to S junonia. the early post-nuclear
whorls are weakly to moderately cancellate in S
trenholmu (Tuomey and Holmes, 1856) from the
Miocene and S. floridana (Heilprin, 1887) from
the Pliocene. In the Miocene species, S. precursor-
Gar Aner. 1948. however, post -nuclear whorls are
strongly sculptured and a spiral row of regularly

spaced nodules are found immediately below the
sutures on the earlier whorls and the body
whorl; the postsutural nodules become obsolete
and replaced by wavy spiral cords and prominent
axial ribs on the remainder of the body whorl in
mature specimens. In the living species, weak to
moderate cancellate sculpture occurs on the sec-
ond and third pt«t-nuclear whorls of some in-
dividuals of S junonia and S. gouldiana (especial-
ly in the fornis named, S. robusta (Dall, 1889) and
S mationae (Pilsbry and Olsson, 1953), some ex-

11 THE NAUTILUS

January 10, 1979

Vol. 93(1)

FIG. 7. The outline of a rachidian tooth o/ Scaphella con-
toyensis n, sp.; greatly enlarged.

amples of which possess nodular spiral bands on
the earlier whorls.). All of the specimens of 5.
contoyensis n. sp. and S. evelina that we have ex-
amined have cancellate sculpture on the early
whorls and near the suture on the body whorl. In
the case of the former species, this sculpture is
essentially microscopic, whereas in the latter
species it is easily seen by the naked eye.

LITERATURE CITED

Abbott. R. T. 1974. Amerimn Seashetls. New York, 663 pp., 24

pl.s.,(>1().5figs.
Adams, H. and A. Adam.s. 18.5.3 [-1&58]. ne Genera of Recent

Motlusca. 3 vols.. London.
Bayer, F. M. 1971. Biological results of the University of

Miami Deep-Sea Expeditions. 79. New and unusual

mollusks collected by R/V John Elliott Pilhbtiry and RA'

Ge)-(l(t in the tropical western Atlantic. Bull. Mar. 5>ci..

21(l):lll-236, 72 figs. ("March i.ssue". published on .June 16,

1971; reprinted, in Studies in Tropical American Mollusks.

pp. 111-236. Univ. Miami Pre.ss.on November 1. 1971).
Broderip. VV. .J. 1827. Description of some new and rare shells.

Zool. Journal. 3(9):81-85, pis. 3-4.
Clench, W. ,1. 1946. The genera Bathyaurinia. Rehderia and

Scaphelhi in the western Atlantic. .Jnhn.iinmi. 2(22):41-6(),

pis. 24-31.
1953. The genera Scaphetta and Aunniopsis in

the western Atlantic. Ibid.. 2(.32):.376-380. pis. 186-187.
Clench, W. ,1. and R. D. Turner. 19frl. The subfamilies

Volutinae, Zidoninae. Odontocymbiolinae. and Calliotectinae

in the western Atlantic. Jnhnsonia, 4(43): 129-180, pis.

80-114.

. 1970. The family Volutidae in the western Atlan-
tic. Ibid., 4(48)::«9-.372. pis. 172-174.
Conrad, T. A. 1863. Catalogue of the Miocene shells of the

Atlantic Slope. Pmc. Amd. Nat. Sci. Philadelphia, for 1862,

14:.559-.t82.
Dall, W. H. 1887. [Correspondence], Conchologists' Exchange

[The Nautilus], 2(1): 9- 10.
. 1889 Report of the Mollusca. Part II. Gastropoda

and Scaphopoda. Reports on the results of dredging ... in

the Gulf of Mexico (1877-78) and in the Caribbean Sea

(1879-80). by the U. S. Coast Survey steamer "Blake" . . .

Bull. Miut. Comp. Zool.. Harvard Univ.. 18:1-492. pis. 10-40.
Gardner. .J. 1948. Mollusca from the Miocene of Virginia and

North Carolina, Pt. 2. Scaphopoda and Gastropoda. U. &

Geol. Sun: Prof Paper 199-B, 179-310. 24-.38.
Habe, T. 19.52. Pholadomyidae, Clavagellidae. Pandoridae,

■luliidae . . . Rlmtrated Catalogue of Japanese Shells. No.

18.PP. 121 -132, pi. 18, 28 figs.
Heilprin, A. 1887. Explorations on the west coast of Florida

and in the Okeechobee wilderness. TVan.s. Wagner Free /«.</.

&•(■.. I:l-i:i4, 19 pis.

Herrmannsen, A. N. 1848 [1846-18.52]. Indicis Generum
Malacozoiman Primordia. Cassel, 2 vols, and supplement.

Kuroda, T. 1931. Two new species of Volutacea. Ventts

.3(l):4.5-49.3figs.
Lamarck, J. B. P. A. 1804. Memoire sur deux especes nouvelles

de volutes des Mers de la Nouvelle-Holland. Am. Mus. Nat.

dWM. Nat. Paris, 5:154-160, pi. 12.

Olsson, A. A. 1965. A review of the genus Voluta and the
description of a new species. Bidl. Amer. Paleont.,
49(224):6.53-672, pis. 80-83.

Pilsbry. H. A., and A. A. Olsson. 19.5.3. Materials for a revision
of east coast and Floridian volutes. The Nautilus 67(1):1-13,
pis. 1-3.

1954. Systems of the Volutidae. Bull. Amer.

Paleont.. 35(152):271-306, pis. 25-28.

Sowerby, G. B., III. 1903. Descriptions of new species of Nassa,
Purpura, Latirus, Voluta, Conns, Stomatella. and Spon-
dylus. Jour. Malacology 10(3):73-77, pi. 5.

Swainson. W. [1831-] 1832. Zoological Rlustrations. Ijondon.

ser.2. 2(11-20). pis. 46-9L
Tuomey. M. and F. S. Holmes. 18.56. Pleiocene [sic] fossils of

South Carolina, containing descriptions and figures of the

Polyporia, Echinodermata, and Mollusca. Charleston, South

Carolina. 1.52 pp.. 30 pis.

Weaver. C. S.. and .1. E. duPont. 1970. Living Volutes, a
monograph of the Recent Volutidae of the world. Mong. Ser.
no. 1, Delaware Mus. Nat. Hist., xv -I- 375 pp., 79 pis., 43
figs., 13 maps.

Vol. 93(1) January 10, 1979 THE NAUTILUS 15

A BIOGRAPHY OF ANDREW GARRETT, EARLY NATURALIST OF POLYNESIA: PART V

W. Stephen Thomas

Director - Emeintus

Rochester Museum and Science Center

Rochester, New Yorl< 14610

Andrew Garrett was an American explorer,
naturalist and artist who specialized in
malacology and ichthyology. He gathered and
studied forms of many other invertebrates, such
as corals and echinodenns, and made careful
drawings of them. He also collected specimens of
insects, birds, plants, and a few anthropological
artifacts, some of which are doubtlessly resting
anonymously in museums or private collections.
He also described and drew watercolors of several
dozen species of shells and several hundred fish,
many of which are as yet unpublished.

Garrett lived and worked in various areas of
the Pacific Ocean from the Hawaiian Islands to
Fiji, the Marshall Islands, the Gilberts, Samoa,
Tonga, the Cook Islands and the Society group.
From 1856 to the early 1870's, his most produc-
tive years, he spent much of his time as a collec-
tor for Professor Louis Agassiz of Hai-vard Col-
lege and in the latter part of this period, from
1873-5, served in the same capacity for the
zoological and anthropological museum of the J.
C. Godeffroy trading firm of Hamburg, Ger-
many. In the last fifteen years of his life, while
located permanently in French Polynesia, he ad-
ded to his own vast collection of shells, part of
which he occasionally sold and exchanged. He
wrote twenty-one scientific papers which were
published in journals in both America and
Europe. One of the monuments of his zealous
work were the 470 species of fishes which he
gathered, described and drew in color for the im-
portant text edited by Dr. Albert C. L. G. Gun-
ther. The Godeffroy Museum published the book,
the first two volumes of which appeared from
1873 to 1875, and the final volume of which was
issued in 1909, twenty years after Garrett's

death. This production remained for forty years
one of the most authoritative publications on
fishes of Oceania.'

Unfortunately the name of Andrew Garrett is
virtually forgotten, except by a few experts. Much
of Garrett's important pioneer efforts in the field
of marine biology were published by other
authors, so that due credit was not always given
him. Only one brief obituary was printed
simultaneously in several scientific journals in
America and England a few months after his
death. A short outline of some of his ac-
complishments was included in the National
Cyclopaedia of American Biography for the year
1899 (vol. 2, p. 162), but not in succeeding editions
or in similar compilations or in histories of
science. For many years his name and accom-
plishments were omitted from print. However, in

* Part 2: Catalogue of Molluscan Species and Bibliograph.v of
Andrew Garrett by William J. Clench will follow in the next
issue of The Nautilus. Manuscripts submitted November It;.
1977.

FIG. 1. Andrew Garrett (1823-1887). Fhntngraph probably
taken in Haivaii about 1863. Original in the Museum of Com-
ixirative Zoology. Harvard College, A/ass.

16 THE NAUTILUS

January 10, 1979

Vol. 93(1)

the last twenty -five years there have been several
short articles about him, one a brief chapter in a
historical treatise on early scientific collecting in
the Pacific' A factor which may account for the
eclipse of Garrett's reputation after his death was
the nonexistence of diaries or personal papers. In
the letters from him which do exist, he seldom
mentions particulars of his private life. Further-
more, his specimens and drawings are widely
scattered throughout the world with no inventory
of his scientific collections ever having been
made. Because of his colorful life and amazing
travels there were many stories and possibly
apocryphal tales. According to one story, Garrett
had a mistress established on each of the islands
where he periodically visited who made scientific
collections for him in his absence. Another story
concerns a queen of a remote locality where he
was staying who induced her subjects to seize a
barrel of his collecting alcohol. He had intended
it to last for a year of collecting but it was con-
sumed in one evening's drunken orgy. There has
been no way of substantiating these tales as they
were passed down by word of mouth. Furthermore,
owing to gaps in our information as to Garrett's
whereabouts it is unlikely that a definitive
biogj-aphy of him will ever be written. However, the
present account is an attempt to present a resume'
of the information that can be documented.

Early Life

This pioneer and largely self-trained naturalist
was bjrn in Albany, N. Y., on April 9, 1823. He
was the third son of fourteen children and spent
part of his early youth near Middlebuiy. Ver-
mont. His father, Francis Garrett, was a native of
Canada; his mother, born Joanna Campanaux,
was a native of Belgium, and of good education.
She sp(jke several languages. After Andrew left
home at the early age of eleven, his family moved
to Albany, N. Y.^

Early in his life young Garrett showed
evidence of both independence and scientific
curiosity. When he was eight years old he left
home without warning to visit a museum one
hundred miles away, and, then, having successful-
ly completed his mi.ssion, returned safely. When
only eleven he was apprenticed to learn the trade

of an iron molder. At sixteen he abandoned this
vocation and went to sea as a sailor for a period
of three years. During that time, according to his
owTi account, he touched at "nearly all the West
Indian Islands, the Cape Verde Islands, off the
African coast, as well as the Azores and Brazil
and several Southern States." Reminiscing on this
exploit several years later, he wrote, "I now went
to work at my trade again, spending my leisure
time studying the plants and shells. Still, my love
of seeing new countries was not in the least
abated so I travelled and worked (1842-1846) in
various parts of the Northern, Middle and
Western States."*

After these wanderings Andrew determined to
go abroad again. Meanwhile, he had not neglected
his interest in natural history, for it was during
this time of roving that he lingered briefly in
Boston, spending happy hours in the museum of
the Boston Society of Natural History. "I
wandered about the suburbs of the city with
Bigelow's Flinri B(if;t(inic))sis in my hand, study-
ing plants. Having travelled in 23 States of the
Union, I concluded to go abroad again."*

Pursuing his ambitions Andrew found himself
on June 7, 1846, signed up as a crew member of a
whaling vessel in New Bedford, Massachusetts. It
was the bark Edward, bound for the Pacific'
Somewhere in the early course of this voyage,
Garrett shipped over to another whaler, the Mza
L. B. Jenney, which had left Fairhaven,
Massachusetts, on November 30, 1846. It was
fi'om this vessel on May 22, 1847, that Garrett
stepped ashore at the busy port of Honolulu. The
place caught his fancy, and he wrote some years
later that he was so much pleased with its ap-
pearance that he made up his mind to settle
there.' This, indeed, was the goal he achieved five
years latei'.

Within a day or two of Garrett's arrival, an
American missionary, the Reverend S. C. Damon
paid a visit to the Jenney. Damon was the editor
of the weekly journal, The Friend, dedicated to
the spread of religion among seafaring men. Used
to boi.sterous sailors who passed through the
Hawaiian Islands, the minister was charmed by
the inquisitive young man who was an amateur
scientist. Such a vivid impression did Garrett

Vol. 93(1)

January 10. 1979

THE NAUTILUS 17

make upon the older man that eleven years after-
wards, Damon wrote; "We recollect to have ac-
companied him to the forecastle, and beheld with
delight the collection of shells which he had
already made. In reply to the question, 'Why did
you ship before the mast?' he answered, 'In order
to study conchology.' "'

That extended sea voyage marked a highlight
in the life of the young sailor not only because of
a variety of adventures but also the experiences
he gained in e.xotic and faraway localities. These
included the Marianas, the Bonins, the Ryukyu
or Liu Chiu Islands, as well as China, the Philip-
pines, and some Australian and East Indian
ports.

When Garrett returned with his vessel on May
15, 1851, to its home port of Fairhaven, adjacent
to New Bedford, he must have gained some
satisfaction as the yield in sperm whale oil
from this voyage amounted to '2,570 barrels. That
was roughly the equivalent of $20,000. Although
Garrett was only a foremast hand on a whaling
ship his share must have been considered a pro-
fitable return for the times. But even more im-
portant to him were the twenty packing cases of
shell specimens which he had assidiously col-
lected during the long voyage. He himself men-
tioned this success six years after the incident
when he was corresponding with his Boston
patron, James M. Barnard. The sailor-naturalist
took pains to mention that the proprietor of a
shell store on State Street in Boston had bought
the shells as well as some of the skins of birds,
specimens of fishes and Crustacea which he had
collected."

Ashore in Boston in the spring of 1851, he
seemed uncertain of what his future held. He was
twenty -eight and he had behind him a rather
rough and wandering life. But he was also becom-
ing more and more engaged in the study of
natural history. The idea of sojourning some-
where in the Pacific Ocean and perhaps spend-
ing his life there must have been in his thoughts.
Even six years before when his whaling ship had
touched at Honolulu, he wrote he had been so
pleased that, "I was determined to settle there"."
During the next year or so after his return he
travelled "through most of the States" as he ex-

pressed it, perhaps working as an iron molder.
Finally, he left California, touching briefly at Rio
de Janeiro and from that port finally headed for
the Sandwich Islands, then also known as the
Kingdom of Hawaii. He arrived in Honolulu
sometime in the spring of 1852, and shortly
thereafter made his temjwrary abode on the
larger island of Hawaii. He remained there, ex-
cept for various collecting trips in othei' parts of
the Pacific, until 1863.

In the Hawaiian Islands

Why Garrett selected Hilo to be his headquarters
will probably never be known. Of course, it was one
of the three Sandwich Island ports preferred by the
captains of the whaling ships from the 1830's until
the time of the Civil War, when the whaling in-
dustry greatly diminished.

In 1850 the total population of the five islands of
the Kingdom of Hawaii was only 84,165 in contrast
to the approximately 840,000 living there today.
The number of foreigners was only 1,962, a little
over 2%. These persons were missionaries, traders,
plantation owners, and others, some of whom had
married Hawaiians and occupied government
jxjsitions. Others were members of the diplomatic
corps. King Kamehameha III was in the twenty-
seventh year of his reign.'

Garrett was an ardent shell collector when he
arrived in Hawaii in 1852 but he lacked scientific
training. Doubtless, it was his association with a
few skilled amateur naturalists which influenced
his future career and raised the level of his in-
terests above those of the mere collector. But, being
somewhat quiet and shy he did not befriend these
persf^ns at once. His acquaintance and friendship
with the avocational scientists of the Islands seems
to have come about gradually.

Above all, it must have been the richness of
nature in Hawaii which aroused and stimulated
the spirit of inquii7. At first he seems to have been
drifting along without any set purpose. We do not
know whether or not he had some occupation or
how he supported himself at this time. However, in
the fall he received a letter from Dr. Wesley
Newcomb, an American physician and naturalist
who had come to the Islands for his health.
Newmmb established a private medical practice

18 THE NAUTILUS

January 10, 1979

Vol. 93(1)

and eventually became government Health Officer,
devoting himself on the side t<^) his hobby of con-
chology. His first scientific paper on land shells en-
titled "New Achatinclla" was published by the
New York Lyceum of Natural History in 1853. It is
known that Garrett collected for Newcomb and
within a year the doctor was proposing to name a
new species of shell in honor of his friend, writing,
"It would afford me much pleasure to embalm your
name not your person, to have it associated with a
fine, new species from Hawaii. When this is fixed,
it descends through all coming time."'

At this time in Honolulu there was considerable
interest in collecting shells, both local specimens
and those from foreign shores. The comings and
goings of sea captains and sailors, traders and
missionaries probably had stimulated this traffic.
The great abundance of tree snails with their
bright colors, gathered by the native Hawaiians,
was another form of trade. There was even a shell
store in Honolulu from about 1852 to 1858, main-
tained by Dominique Frick, who had once been the
French consular agent.'

We know that Newcomb left for the United
States in March, 1855, but we do not know much
about Garrett's association with other naturalists,
e.xcept that he was collecting and had access to a
limited amount of literature and at the same time
was teaching himself to draw and paint. It may
have been due to loneliness but also due to his
aspirations of becoming a professional collector
that Garrett on January 29, 1855, wrote a letter to
one of the most distinguished scientists of his day.
He addressed it to Prof. Louis Agassiz who had
recently arrived in the United States as lecturer at
Harvard and who, anxious to build up a core of
collectors throughout the world, had issued some
printed literature soliciting contributions. Garrett
included sample drawings of fishes and some in-
vertebrates, explaining he would continue to make
sketches... "so that in the event of your observing
any new species, or such as you would like
specimens of, you can inform me. . . I do not make
any pretensions to a knowledge of Ichthyology. . .
yet will endeavor to write a description of each."
He continued that he would be glad to exchange
specimens in any branches of natural history and
desired in return either specimens of shells new to

him or copies of such books as Storer's Fishes of
Massachusetts or of Dr. Gould's books on shells.'"
Although the financial resources of Harvard
University were at a low ebb, a very fortunate
arrangement was made through Agassiz's Boston
friend, the merchant and shell collector, James M.
Barnard.

By September, 1856, almost seventeen months
later, Garrett received a reply to his inquiry to
Professor Agassiz. It was from Mr. Barnard, writ-
ten on the professor's behalf, inviting young
Garrett to become a zoological collector on a per-
manent basis. Garrett replied that he was most
happy to do so as he had no regular employment
and was on the point of returning to the United
States. In his letter of acceptance, he concluded to
charge $400 per year which would cover all of his
traveling expenses, food, hiring of assistants, his
own salary and would further enable him to go on
various ships to remote islands."

The impetus furnished by Louis Agassiz for him
to apply and improve his already self-acquired
scientific techniques of observing, collecting and
recording came to Garrett at what seems an ap-
propriate time. On December 1, 1856, at Hilo he
shipped aboard the whaleship, Lydia, whose master
was John W. Leonard. Considering the territoiy
covered in the voyage which included the Society
Islands and some of the Marquesas Islands, the
vessel was away from Hawaii for the surprisingly
short span of three months. The voyage was highly
.successful from the point of view of the variety and
number of specimens gathered, but a tragic event
came later. After the reshipment of the rollections
to another vessel, the Joh)) Gilpin, the latter vessel
was wrecked on its return to the United States in
November, 1857, and its cargo lost, which included
considerable but not all the material destined for
Harvard.'^ It happened there were duplicates
retained by Garrett and some of the fish pictures
were already in the possession of Captain Leonard
who eventually reached home safely.

Recently, through the courtesy of Barbara John-
son of Princeton, an interesting letter from
Leonard to his wife, Lydia, has come to light. It
provides confirmation that the American
naturalist was making fish pictures specifically for
Captain I^eonard. In part, I^onard s;iid, "Since I

Vol. 93(1)

January 10, 1979

THE NAUTILUS 19

wrote last we have passed through several stirring
adventures (new). We have been at Fannings
Island, and Mitui, one of the lower archipelagos.
And, also at the Island of Huehine [sic] where we
have gathered a splendid lot of shells and fishes.
We have a naturalist (Garrett) as Passenger with
us which makes it very pleasant. And he is painting
a fine lot of Fish for me and collecting a beautiful
lot of shells. So I shall have a fine Colection [sic]
when I get Home."" Of course, the principal
benefactor was Harvard College and its museum of
natural history. Later, most of this material was
described and pictured in the publication of the
Godeffroy Museum of Hamburg.

We have in this statement Leonard's
corroboration of the fact that part of this was the
same collection of watercolor drawings, all drawn
by Garrett, which survived in the family of John
Leonard's descendants. They are now the property
of the author of this article. A further item of in-
terest is that the Leonard set contains a Garrett
picture of a beautiful wrasse fish of the family
Labridae which the artist -scientist named Julis
leonardianum undoubtedly in honor of his whaler
friend.

A few months after Garrett returned from his
voyage to Hawaii, he received a four-page letter in
the handwriting of Professor Agassiz, addressed to
John M. Barnard but intended for the naturalist-
employee. It has significance, for it served as a
guide for proper collecting and scientific ob-
servation. A total of three such letters from Agassiz
composed for Garrett's benefit still exist and are
preserved in the library of the Bishop Museum in
Honolulu. The first one, dated August 28, 1857, ex-
plains:

"The principal merit of collections of objects of
nature is not desired in our days from the ac-
cidental circumstances that they may contain new
species but from the opportunity they afford of
elucidating natural laws. The collector ought,
therefore to have his attention constantly turned to
this important end and must on that account
collect in a particular way. . .'"

He went on to e.xplain that large quantities of
specimens of one species in all sizes should be ob-
tained as they all afford the means of ascertaining
the range of different species. He added that the

slightest difference between specimens of adjoining
localities should be taken into account. Even in the
case of adjoining islands "or opposite shores of the
same island specimens must be collected of
everything. . . It is thus ascertained that the dif-
ferent groups of Islands of the Pacific may be
inhabited by distinct representatives but identity
nuist be made out by direct comparison and can
neither be assumed or denied before hand".

Meanwhile, the instructions Garrett had re-
ceived for collecting and his own zeal compelled
him to adopt and use more precise methods.
Through a letter to Barnard, written after the trip
on the Lydia. he reported on his field collecting. He
explained that he made it a point to gather those
specimens which did not often occur. "When
searching along the coast I have to take pencil and
paper, an assortment of small jars, boxes and
calabashes which my native boys carry. And when I
find anything I which to preserve I first note the
depth of water, kind of bottom, its mode of
locomotion and colors while alive. And I find it
necessary to preserve them in water while carrying
them about so that their delicate parts will remain
perfect until I can place them in alcohol." He said
that he found it essential to make rough sketches of
many objects in order to give a clear idea of their
markings. He, also, added that he had his own
catalogue of the crustaceans in which he recorded
everything relative to each species which he
found.'* It so happened that at the time Garrett
mentioned his misgivings as a scientific field
worker. Professor Agassiz had time to examine
some of the young worker's drawings. In an un-
dated letter to J. M. Barnard, probably written in
the fall of 1857, he said "I have been much pleased
with the drawings as well as the descriptions of Mr.
Garrett. They will be invaluable material to clear
up the Natural History of the Pacific Ocean but I
would warn him not to be hasty in publishing
them.""

Relationship with
William Harper Pease

William Harper Pease (1824-1871), surveyor
and conchologist, reached Hawaii when he was
twenty-five years old. He had travelled in Mexico
with General Scott's army and had made extensive

20 THE NAUTILUS

January 10, 1979

Vol. 93(1)

collections there of birds, insects and other fauna
for the Academy of Natural Sciences of Philadel-
phia. Even at that early age, he had already pub-
lished the first of his scientific papers which
totalled 82 articles by the time of his death. Pease
cho.se to be in Hawaii for reasons of health, reach-
ing there in 1849 and residing in Honolulu until his
demise in 1871. In a short time he became an im-
portant man with interests enabling him to travel
through the islands. He worked as a land surveyor,
and held the position of Assessor of the City of
Honolulu as well as being Commissioner of Water
Rights. But, preeminently he was a scientist.
Like Garrett he was a self-taught naturalist but by
the time they met. Pease had acquired the dis-
ciplines of scientific research and was an inveterate
collector. Pease helped Garrett not only by engag-
ing him as his principal collector but allowing his
friend to use his conchological and scientific books,
instructing him in method of research and in other
ways. It is very fortunate that there was such a
person available to Garrett for his guidance and
stimulation, and as the two first met in 1857, in a
sense Pease took the place of Newcomb who left the
Islands in 18.56, and had formerly been the young
collector's friend and mentor.

For six yeai"s despite the various absences of
Garrett on collecting trips, they saw each other
fairly frequently. After the summer of 1863,
Garrett left Hawaii never to return before Pease's
death in 1871. but they kept up a faithful
correspondence. A group of letters from Pease to
Gari'ett written during the whole period of their
fiiendship (1857-1871) sun-ives in Honolulu's
Bishop Museum. Excerj^ts from them are given in
the series of articles by Karl W. Green published in
I960." and others were quoted in the biography of
Pease by Dr. E. Allison Kay.' The relations of these
two men was friendly, although Pease took almost
a paternalistic attitude toward Garrett. There was
a difficult side for Garrett. It is true that, in a
sense, he was an employee of the other man, but in
some ways Pease seems to have taken advantage of
Garrett's abilities and efforts. The latter worked
hard and laboriously. He collected amid the most
trying and dangerous conditions. He scrupulously
described and drew pictures of many of the
specimens gathered, particularly the fishes. In the

case of fishes and shells he suggested the scientific
names. But despite all this, he lived in the shadow
of Pease while the more articulate writer and more
assertive man earned the glory.

Collecting in the Kingsmill Islands

Was it restlessness or a desire to form collections
ft-om le.sser known areas that goaded Garrett to
make so many scientific forays? We sense that the
business arrangement with the museum at Har-
vard as well as the enthusiasm of both Professor
Louis Agassiz and the Boston businessman James
M. Barnard, must have been the stimulants to these
persistent travels.

Hawaii was a focal point from which trading
schooners and whaling ships, served as a means of
transportation. One of the latter was the brig, Mar-
ni)i(] Star, operated by the Board of Missions to con-
vey American missionaries and their trained
Hawaiian assistants to the various, far-flung island
stations." These mission voyages were financed by
sums of money raised, largely by New England
school children. Garrett explained that he had
made reasonable arrangements as a passanger
aboard the Moi-ning Star paying $1.50 per day
while he stayed on board, with an additional charge
for his package of specimens. A plan developed so
that he could sail directly to one of the islands and
stay there collecting for three months."

Our conchologist carried complete provisions as
well as articles of trade to last him at least four
months. The materials included cutlery, edge tools,
beads, calico cloth and even 400 board feet of lum-
ber with which to build wooden boxes for the
return of his specimens. The brig, Morning Star,
left Hawaii on August 11, 1859, but due to adverse
winds and currents took longer for the trip to the
South Pacific than would ordinarily be the case.
Finally, after a voyage of three weeks from
Honolulu, the two-masted vessel reached its
destination on September 9th. This was Apiang,
one of the northern islands of what are now known
as the Gilberts in Micronesia. It must have been a
strange, remote place, being flat and palm-covered
coral rock. It was about fifteen miles square and
had a total of not over 300 to 400 inhabitants, living
in small, scattered villages. While the Rev. and
Mrs. Hiram Bingham, who ran the mission, lived

Vol. 93(1)

January lU, 1979

THE NAUTILUS 21

near their thatched church a scant distance away,
Garrett established himself in a rather flimsy,
borrowed dwelling. With the limited help of his
servant Temawa, the naturalist busied himself in
making e.xtensive collections. To do this he daily
waded for long hours over the inner and outer plat-
forms of the nearby lagoons. He also exchanged
small bits of his trade goods for selected specimens
of fish, shells, echinoderms, and other forms of
aquatic life. Several dozen natives crowded around
him almost every hour of the day, causing him end-
less misery. This slowed down his work of
preparing specimens, making drawings and jotting
down notes. Their repeated attempts to steal his
belongings made him worn,' that they might seize
and drink the precious preserving alcohol, so that
he frequently worked into the late hours of the
night when his unwelrome guests were not around.
After some days of deceiving the natives about the
alcohol, they detected its smell. They would have
taken it from him had he not convinced them that
it was poisonous type of substance. Another
nuisance he had to bear were visits by inhabitants
of other islands. All of them demanded to see and
handle what they called his "wonders". These were
a mechanical music box, a magnifier with mirror,
and the "plates" or pictures of natural history sub-
jects which he had brought with him or had done on
the spot. Although his companions demanded that
he buy all their zoological specimens they brought
to him in large quantities, he found it judicious to
acquire only a few representative ones from each
lot so as not to discourage the vendors from con-
tinuing to collect for him. Lacking a knowledge of
the language, he was compelled to use pantomime
combined with mixed words of Hawaiian and
English, but seemed to succeed fairly well in com-
municating. Unfortunately, at frequent intervals
he was ill with fever or other complaints and when
attempting to rest, found: "a pair of black eyes
glistening at every crevice in sides of the house."
Sometimes, due to the crowds of noisy visitors, for-
ty or fifty in a group, he had to close up his house
and take long walks to get away from the tumult."

From time to time the busy collector had some
contact with the ruler. King Tekaiia. This person
did not seem to be a real monarch. Garrett
described him as a large, corpulent man whose only

clothing was a rough mat of leaves wrapped around
his loins. He lacked the respect of his subjects who
seemed to ignore his authority. When one day
several unfamiliar natives arrived from the nearby
Island of Maraki, Garrett noticed that they were
"bringing with them several Kanaka heads. They
stated that there had been a battle. . . and the heads
were those of some of their friends who had been
slain and they had cut them offf and fled to prevent
them (the heads) from falling into the hands of the
enemy." One detects a note of reprovement in our
traveler's remarks on his observations of the
Micronesian Christian converts. They often dozed
during the sermons of the missionaries or plucked
and ate the lice from each other's heads while at-
tending church. He was further shocked when one
day in passing the council house he was overcome
by the stench from a putrid corpse. It was the body
of an elderly and venerated chief whose funeral ser-
vices extended over several days.

Despite the hard times and vicissitudes which
the naturalist had to endure, one realizes from his
journal how enthusiastic and excited he became
when he encountered new species of shells and fish.
On its return from Apiang with Garrett and his
booty aboard, his ship stopped at Ebon Island
where he acquired additional specimens. When he
arrived back in Hawaii on January 11. 1860, he
must have had considerable satisfaction in the suc-
cess of the expedition. A record of the importance
of the venture is also incorporated in the official
report of the Harvard Museum quoting Agassiz on
the acquisitions from the Pacific Ocean, which
stated, "the total number of specimens of fishes
amounts to five thousand, comprising 1.000 dif-
ferent species, the most important of which are
from the Kingsmill and Society Islands, collected
by Mr. Garrett"^" Despite this account it is quite
likely there was an error in the report as the collec-
tions noted probably included shells and other
organisms in addition to fishes.

Second Visit to the Society Islands

It is unfortunate that there is such scant in-
formation about Garrett's second visit to the
Society Islands which took place from 1860 to 1863.
The Society Islands offered ample opportunities for
new discoveries, despite the collections of Captain

22 THE NAUTILUS

January 10, 1979

Vol. 93(1)

James Cook's associates, Lesson, Hugh Cuming,
and otliers. Commenting on the early work of these
scientists, Garrett, writing some twenty years later
in his own research article, remarked "During the
years 1860-1863 I made a much more thorough ex-
ploration (of land shells) than any of my
predecessors, and by searching in nearly every
valley of the group, discovered 50 new species. . ."^'
He left Hawaii for Tahiti and the other islands in
May, 1860." The manner of life of the natives there
had probably not changed appreciably since his
visit of three years previously when he observed, ". .
conditions being there the same as at the Sandwich
(Hawaiian) islands in the form of indolence,
drunkeness, and the most loathsome diseases which
he felt were rapidly decimating the population. I
cannot perceive as they have improved an iota in
there moral or physical condition notwithstanding
40 years of missionary labor and intercourse with
foreigners.""

More importantly, he wrote of the marked
similarity in the marine fauna in French Pol>Tiesia
in comparison with that in the Sandwich Islands.
Though the natives of each island group spoke a dif-
ferent language, they used the same name for the
same objects common to both areas. He noted that
residents of Boston, New York and Baltimore had
two or three names for the same natural species.
Still he found natives living 2,000 miles away from
one another speaking almost a different tongue but
using the same name for the same species of fish.
"All Polynesian Islanders have with very few ex-
ceptions a distinct name for ever>' kind of animal,
plant and mineral, no matter how small and ob-
scure the object is." He concluded by saying "They
as a mass have a better knowledge of the natural
productions of the islands than the mass of people
in the United States"."

Although we have so little information about
Garrett on this particular Society Island sojourn,
we do find a reflection of his interests in the letters
Pease wrote him and which he so carefully kept. On
September 2, 1860, Pease wrote proposing their
collaboration on a series of popular natural history
publications which would contain lithographs of
the watercolor drawings as well as printed descrip-
tions of the more common fishes, shells and plants.
"My opinion is the most effectual mode is to

publish a small pamphlet in numbers, similar to
those of Professor Adams, 'Contributions to Con-
cholog>''. I think I shall issue one before you
return." Pease went on to explain that the
publication would contain "your descriptions of
fishes and a portion of the descriptions of shells I
have forwarded to Cumings."" It is quite likely
that a series of 30 handwritten sheets of descrip-
tions of fishes and shells of both Hawaii and the
Society Islands in Garrett's handwriting with bor-
ders drawn around them, each with a watercolor
drawing, are part of the group previously men-
tioned as now owned by the author were intended
for the pamphlet. Unfortunately, the projected
publication never appeared as far as is known.

In the Central Pacific (1863-69)

Apparently Garrett returned from his Society
Island explorations about July, 1863. The months
that followed were crucial ones as he decided to
abandon his base in Hawaii and go off on even more
extensive voyages. In welcoming him back to
Honolulu, the Rev. Samuel C. Damon, reporting en-
thusiastically of the naturalist's accomplishments,
wrote ". . . he has visited every island and every
valley and reef of every island, collecting specimens
of shells, fishes and every variety of animal and in-
sect. The extent of his collections may be indicated
by the fact he has used three hundred gallons of
alcohol in preserving the specimens. He has col-
lected 400 different species of fishes. Each one of
these is beautifully painted from life. Some of his
drawings which we examined are executed with
great skill and taste. The number of these
specimens which were forwarded from the Society
Islands would not fall below ten thousand. "^^

With his long journey behind him and with his
collections shipped away, he had to put off the blan-
dishments of his friend Pease. The latter was in-
sisting that he remain and help with his projected
commitments for publication. In fact. Pease at this
time was writing several papers on land shells
probably based in part on Garrett's collections.
Eight papers appeared, chiefly on this topic, with
Pease's name attached in the Proceedings of the
Zoological Society of London between 1864 and
1865.'

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 23

Garrett, making preparations for his next ex-
tended voyage, received a letter dated October from
his San Francisco agent, Sam Hubbard. He had
purchased for him a supply of alcohol, a music box
with which to entertain the natives, a magnetic
machine (which may have been a surveying instru-
ment), and a series of other articles. The most
expensive item was a complete wet plate photo-
graphic apparatus which included a camera, plates
and chemicals. It cost $376.76, an enormous sum,
considering that Garrett's yearly salary was only
$400.

Another important activity for Garrett in his
1863 stay in Hawaii was identifying both shells
and fishes for the California Academy of Sciences.
That institution had made him a corresponding
member in 1856 and its Proceedirujs in 1857 had
carried his article on marine shells, probably his
first scientific contribution to be printed.^ That
same organization, hearing of his new expedition,
sent him twenty gallons of preserving alcohol
which they said was to be used "according to your
best judgment, taking sufficient of it to reimburse
yourself."^

Meanwhile, in August, Damon, in the same letter
referred to, outlined the extensive South Sea
Islands voyage the conchologist was planning. It
would include the Marquesas Islands, the Naviga-
tors (Samoa), Friendly (Cook) and the Fiji Island
groups. This would be a period of no less than five
or six years which he would devote to new ex-
plorations. Damon added, ". . .he is perfecting him-
self in the photographic art, as he will go prepared
to take views of natural scenery, animals and the
inhabitants of those remote regions. Hereafter, his
researches will embrace a wider range than they
have hitherto done."

Late in 1863 Garrett got off but we have only a
vague knowledge of his specific locations in the
next six years. He chose for his collecting grounds
two main areas 2,000 miles and more south of his
former haunts in the Hawaiian Islands. These
were, first, the Tuamotu Islands, a large ar-
chipelago, stretching from 140° to 150° West
Latitude and situated east of the Society Islands.
He seems to have been there for most of 1864 and
1865 but we have no records of the precise places of
his collecting. For the second part of his travels, he

was in the Cook Islands, Western Samoa and, then
for a good part of 1867 to 1869 he moved about the
Cook Islands.

Garrett was not only doing his usual collecting
but was also taking photographs of the native
people. We have already noted his purchase of a
camera and the necessary equipment. On Januar>'
20, 1864, not long after his departure from the
Hawaiian Islands, Pease wrote to him ". . . Not a
day passes without my dreaming of your fortune
and success. I have imagined the missionaries
might decide that your photographs were a useless
article of furniture and discourage the natives from
patronizing you, and then again I think I see you
surrounded by a crowd of natives, dancing and
shouting with the pictures. I shall be anxious to
receive your first letter.""

During the period 1863 to 1866, according to a
recent writer, Pease continued to sponsor Garrett's
trips at least in part and continued to act as his
agent in Honolulu. Garrett sent Pease descriptions
of his living specimens and drawings of shells and
nudibranchs for inclusion in the numerous papers
Pease was writing.'

It cannot be accurately determined when Garrett
ceased his activities on behalf of Harvard's musuem
but it was sometime around 1863. Agassiz was
having financial troubles at this time. Another
factor could have been unfavorable circumstances
brought on by the Civil War or other reasons which
might have terminated James M. Barnard's annual
payment of his salary. Certainly, the slacking off of
American vessels engaged in the whaling industry
all over the world may have been a contributing
cause. Some of these vessels had been acquired by
the Federal Government to be taken south and
sunk to block up shipping in southern coastal ports,
while others which were already at sea at the out-
break of hostilities were captured or destroyed by
the Confederate Navy.

Garrett and the Godeffroy Museum

These circumstances may well have helped bring
about Garrett's affiliation with another
organization. Ever since the early 19th century an
important shipping and trading company of Ham-
burg had operated vessels between Germany and
South America's west coast. This was the firm of J.

24 THE NAUTILUS

Januao' 10. 1979

Vol. 93(1)

C. Godeffroy and Son, which after having suc-
ces-sfully managed a fleet of cargo-carrying
passenger ships to South America, Australia and
California, found its business cut off after 1855. In
that year one of its representatives, August Un-
shelm, had been following orders seeking out
business possibilities of trade for native products in
such Pacific islands as the Carolines, the navigators
(Samoa), the Friendly (Cook Islands) and the Fiji
Islands. As a permanent headquarters and trading
station for the whole area the firm purchased land
at Apia, Samoa. For the next twelve years this
grew into an impressive establishment with its own
plantations of coconuts and cotton and a trading
center serving several large clusters of remote
islands. By 1864, a new Godeffroy employee, young
Theodore Weber, took over as head of the business
at Apia. He acquired more land and directed the
production of copra which after its arrival in
Europe was processed into candles and soap.^

Meanwhile, back in Hamburg, Johann Caesar
Godeffroy, head of the firm, had a museum to house
exhibits of rare material of the Pacific Islands in
the fields of anthropology and zoology. He had
hired a young Swiss zoologist, Dr. Edward Graeffe,
to set up and display the collections which were
being supplied by the captains of his twenty dif-
ferent vessels then travelling back and forth bet-
ween Hamburg and Oceania. They had special in-
structions to secure natural history specimens and
native artifacts. A year later, J. D. E. Schmelz, a
qualified scientist, became custodian when Godef-
froy sent Dr. Graeffe out to Samoa and Tahiti on a
ten year assignment as collector for the new in-
stitution. Simultaneously, the Musuem sent a small

band of collector-scientists into the field. Garrett
became one of these about two years later."

By 1866 Garrett was established in Samoa and
busy collecting on the Islands of Upolo and Savaii.
His name had been known previously in Hamburg,
as some of the shells he gathered were sold to the
Hamburg government museum in 1862. About this
time at Apia he came into the good graces of the
Godeffroy representative, Weber, and in 1866 the
American had obtained passage on the company's
ship the Alfred which transported him to the Fijis.
The agent reported this in a letter to his employer
sent from Samoa August 17, 1866, requesting that
Garrett be permanently engaged. Godeffroy ap-
proved this recommendation and authorized
Garrett to gather zoological specimens. Godeffroy
promised to send the needed supplies for collecting
and preserving. Garrett was to receive five hundred
Chilean pesos for the first year, as well as free
passage in the company ships and to be treated
"always in the kindest way possible." In return for
the payment and ship accommodations, the
scientist was to provide a selection of his specimens
for the company museum."

It is particularly unfortunate that no detailed
account of Garrett's activities in the Fiji Islands
survives. Because of unstable political conditions of
the country and the presence of savage cannibals he
worked under extremely difficult conditions. Un-
doubtedly, he was befriended by a few American
and English missionaries. The kingdom had for
several years carried a heavy financial debt to the
United States incurred when the home of the
American consul had been destroyed by a mob. Fiji
had even sought to be taken over as a protectorate

^/t^i /K

■vy -cr-.

A^ .^nz: fi-c^, M S. S^:^x^^ ^ J^J.^^ ^^-^^ — ^

FIG. 2. A sample of Andrew Garrett's handirritiny and signature fivni an ISX? letter irritten
Hauhine Island. Society Islands t(i W. I). Hartninn of West Chester. Pa Oriyinai in the Smithsonian
Institution.

Vol. 93(1)

January 10, 1979

THE NAUTILUS 25

first by Great Britain and then by the American
government but both offers had been refused.
Finally, a Confederacy of Independent Kingdoms
had been established in 1865." In 1868, when
Garrett was there, a Polynesian Company had been
formed to pay U. S. claims against King Cakobau in
exchange for concessions. Looking back on his three
year experience in that amazing cluster of 8(W lit-
tle-explored islands, Garrett wrote in a letter nine
years later ". . . in the Viti (Fiji) group I had several
narrow escapes both from the natives and from
drowning. They killed several whites, including a
Missionary while I was there. The latter, together
with several native teachers, were served up at one
of their cannibal feasts. Shortly after I left the
group there were a number of white residents
killed by the savages, showing what risks the shell
collector experiences when searching these
regions."^'

However, there is proof of Garrett's success in his
collecting activities in the Fiji Islands. The sales
catalogue of the Museum Godeffroy notes: "In
regard to further research we advise that Andrew
Garrett, well-known through his collection for
Professor Agassiz and the fact that he has made the
South Sea Islands his main task, has for some time
extended his efforts on our behalf. The first ship-
ment consisting mostly of animals of the Viti
Islands has just arrived here. It consists of many
interesting species such as amphibians, fish,
crustaceans and a few polyps, worms as well as in-
sects."^"

But despite there somewhat pleasing results, a
real tragedy occurred when a large portion of his
final collections were destroyed in a shipwreck.
Writing over two years later from Tahiti Garrett
described his loss: ". . . When taking my departure
after two years hard work I suffered a shipwreck
and lost all my books on conchology, all my dried
plants, Insects, Bird Skins, part of my Shells, Notes
and Drawings and a series of Portraits of Natives
which I had photographed. Fortunately, most of my
shells had been shipped to Samoa in another
vessel." He concluded by saying that from what he
had saved from the wreck and what he had pre-
viously shipped to Samoa, I find about 1500
species of Viti (Fiji) shells and probably lost one or
two hundred more.^'

Last Years on Huahine (1870-1887)

After 1870 Garret spent his remaining years in
the Society Islands. He had established a home
there, having made several stops on previous
voyages. One should not be surprised that he chose
the attractive island of Huahine, ninety miles nor-
thwest of Tahiti, as his permanent home. It is a
volcanic island of approximately ten square miles
in area with twin mountain peaks, one of them
rising over 2300 feet above the sea. His own descrip-
tion, written after his first encounter early in 1858
while a passenger aboard Captain John Leonard's
whaleship. Lydia, says "The Island, in fact, consists
of several islets which are separated by narrow
channels. They present a bold and mountainous
aspect, and are clothed in the most luxurious ver-
dure from the water's edge to the summits. . . A
short distance back there arises an amphitheatre of
hills and mountains which are covered either with
tall, rank grass or dense dark forests, and, the
whole coast consists of a dense mass of fruit and
splendid flowering trees, all combining to form one
of the most delightful tropical scenes I ever wit-
nessed."*

Although we find some evidence that he
travelled (probably by small sailing canoe) among
the nearby islands of Raiatea and Moorea, and may
have made occasional business trips for mail and
supplies to Papeete, the capital and chief seaport,
he had much to occupy him at home. He was busy
making up selected sets of his duplicate shells and
either selling or exchanging them with collectors in
Australia, England, France and the United States.
This work which involved comparison of shell iden-
tifications led to extensive correspondence with
both amateur and professional conchologists in-
cluding R. E. C. Stearns of San Francisco, Berlin H.
Wright of Penn Yan, New York, Rev. E. R. Beadle
and George W. Tryon of Philadelphia, and various
others. He maintained a steady correspondence
with Dr. W. D. Hartmen of West Chester, Pen-
nsylvania, and some of these letters from Garrett to
the latter individual from 1874 to 1887 survive in
the Carnegie Museum, Pittsburgh, Pa. In the mid-
dle seventies and early eighties a total of eighteen
of Garrett's Scientific papers were published in the
Journal of the Academy of Natural Sciences of

26 THE NAUTILUS

January 10. 1979

Vol. 93 (1)

Philadelphia, the Journal de Conchyliolo(jie in
Paris, and other scientific periodicals.

During the first two years on Huahine
(1870-1872) he must have devoted ojnsiderable
time and energy to finishing and perfecting the
descriptions of the collected specimens and the
watercolor drawings of 476 different species of
fishes from Hawaii, the Society Islands and the
Fijis. Johann Caesar Godeffroy received this
material in 1872 and thought so highly of it that he
had the project edited and prepared by the
celebrated ichythyologist of the British Museum,
Dr. Albert C. L. Gunther. These compri.sed volumes
1 and 2 of the prodigicjus work, "Andrew Garrett's
Fische der Sundsee", published in Hamburg as part
of the JounwJ of the Museum Godeffroy. Un-
fortunately, the dissolution of the business of J. C.
Godeffroy and Son in 1879 delayed further
publication. But the final volume. No. 3 was issued
in 1909. This work remained the ultimate authority
on the fishes of the Pacific Ocean for almost forty
years.^^

Little has come to light of Garrett's private life
but we know he was legally married to a woman
named Otari. One account states she was a
Samoan^ and another informant, Alvin Seale,
wrote after a visit to Garrett's home at Huahine on
January 1, 1903 that Garrett's wife was the
daughter of a high chief of the Island. It is not
knovm whether or not they had any children,
although the author made investigations of records
on this topic on his two visits to Huahine and
Tahiti in 1961 and 1974. He did find the site of
Garrett's dwelling which was a short distance from
the village of Fare. Mr. Seale describes it as "a neat
little frame house, very comfortable and situated in
a nice garden". It was on the edge of a bay and in
sight of the ocean.''

In 1878 Garrett contemplated going to New
Caledonia where he had a friend, (probably
Rossiter] and also to the Solomon Islands. Instead
he wrote Dr. Hartman of reports he had received of
massacres of the whites by natives. ". . . Not having
the slightest ambition to become a martyr in the
name of Science, I think it will be the wisest course
to postpone my visit to those savage islands."'*

Fortunately this remarkable man did not suffer
the kind of death he had feared in the far off can-

nibal islands but in a sense his passing was no less
li-agic as he died of a lingering case of cancer. On
June 25, 1887 he wrote his friend Hartman in
distant Pennsylvania: "As regards myself I have
bad news to write and think this probably will be
my last letter directed to you. I have been troubled
some time back with a diseased mouth. The French
doctors in Tahiti call it a ver>- bad cancer and it has
developed too far to be successfully treated by
•surgical operation. In fact, it has been so bad and
painful that life is a burden and for some time I
have been unable to work in my collection. . . I may
jiossibly linger along for several months. I am too
weak to write much, so I will thank you over and
over again for your past kindness to me. . .""

Garrett died on November 1, 1887, and is buried
in the missionary cemetery under a large tamanu
tree at the edge of the village of Fare. The grave,
with an inscribed marker, surrounded by a .small,
iron fence, still survives and is kept in good repair
at the expense of the French government.

It was fortunate that the English minister. Rev.
Ebenezer V. Cooper, Garrett's neighbor, wrote a
brief but fairly accurate obituary. It was published
with a bibliography a few months after the scien-
tist's death in four different conchological
magazines, namely "The Conchologist's Exchange",
"The West American Scientist", "The Journal of
Conchology" (London) and "Science".'

The Personality of Andrew Garrett

What few descriptions we have of this now
almost forgotten explorer-naturalist give us an
impression of a sincere and gifted personality.
Garrett was serious, intelligent, and blessed with
prodigious energy and drive. Many times he had
been in great danger and must have had unusual
physical endurance, having been exposed at sev-
eral times to shipwreck, tropical diseases, and ex-
treme fatigue. One of the most striking of his
characteristics was his ability to overcome the
handicaps of very limted formal education. His
missionary friend, the Reverend Ebenezer Cooper
wrote, "He was self-taught in every sense of the
word and his ability and achievements were
wonderful and striking."' He advanced himself in
reading and he so practiced himself in writing
that he eventually acquired a commendable and

Vol. 93 (1)

January 10. 1979

THE NAUTILUS 27

vigorous prose style. His artistic ability, very
crude at first, with persistent effort enabled him
to draw not only with scientific precision but
with aesthetic quality as well. As for languages,
he could speak Polynesian, at least the Hawaiian
fonn of it, and probably could use some French
because of its commercial and social usage in the
Society Islands where he spent one third of his
life.

In appearance, he was a lank, partially bald
man even in his early thirties, and had deep
cavernous eyes to judge from the only portrait
known to exist which he sent to Agassiz at the
time he was engaged as a collector by the Mu-
seum of Comparative Zoology at Harvard. He was
slim, apparently of medium height with slightly
stooped shoulders, side whiskers and a full beard.
He looked older than his true age and might have
passed as a down-at-the-heels missionary or even
an intellectual beachcomer. One person who knew
him well remarked, "He was very unpretentious
and no one from casual observation would im-
agine him to be a savant. . . Outside, his own
special study of Conchology, he was deeply read
in kindred subjects and no brand of natural
history seems to have been overlooked." In his
later life he possessed a good working library of
books and pamphlets in his specialty and these
books are now preserved in the Bishop Museum
in Honolulu.

Although a shy man and apparently not en-
dowed with an exuberant personality, he instilled
quiet admiration and even warmth in his close
friends. Dr. Wesley Newcomb was so pleased
with him that he promised to name a new species
of shell in his honor. One of his closest friends,
William Harper Pease, in innumerable letters be-
moaned his long absences which often lasted for
years at a time. His staunch supporter, the mis-
sionary Damon, was constantly praising him and
his rare qualities. One of Garrett's defects seems
to have been his poor luck in business affairs
and, perhaps, his over confidence in individuals
whom he trusted who took advantage of him in
failing to pay their debts. At times, he seemed to
lack normal assertiveness.

Encomiums on the accuracy of his scientific
work have come from a number of sources in-
cluding Agassiz, Pease, Gunther, and more

modern scientists such as Herbert H. Smith,
Alvin Seale, Spencer Tinker and others. Especial-
ly noteworthy were the statements of the
authority on Pmiuln tree snails of Polynesia and
Melanesia, Dr. Henry E. Crampton, Professor of
Zoology in Columbia University. Crampton made
at least five expeditions over a period of 18 years
to many of the islands where Garrett had col-
lected forty or fifty years earlier. Crampton
wrote, "But, above all others, the name of Garrett
stands out prominently. . . the rich fruits of his
masterly studies are the shells described mainly
by Pease and the precise descriptions of their
habitats specified with an exemplary minuteness
his own notable monograph. . . It is this work of
Garrett's that forms a solid basis for comparison
of the present intrinsic and distributional
characteristics of Polynesian species in their con-
ditions and situations. . ."" The same appraisal
has been given by Dr. William J. Clench who said
that Garrett deserves great credit because he
recognized the hyperspecific localities and
realized the value of numerous species from a
variety of regions. He perceived the changes made
in a species by changes in topography.''

One man, a contemporary from another profes-
sion but thoroughly familiar with Garrett's field
work, Rev. Samuel C. Damon, was prophetic
when in 1863 he wrote: ". . .we are bold to assert
that there are but a few men in the world whose
labors are intrinsically of more value to natural
history. Take for example, his late exploration of
the Society Islands. It is undoubtedly more im-
portant than that of any English, French or
American exploring expedition which ever visited
these islands. . . We are confident no explorer is
more worthy of their notice, or has contributed
more largely to widen the sphere of science and
knowledge.""

Acknowledgments

The author is especially indebted to his late
cousins, Francelia and Aurilla Leonard of
Fairhaven, Massachusetts, who gave him a set of
over 250 watercolors and drawings of fishes and
shells made by Andrew Garrett. Many scientists
and museum workers assisted in his forty-six-
year researches, especially William J. Clench of

28 THE NAUTILUS

January 10, 1979

Vol. 93(1)

Harvard University; the late E. W. Gudger of
the American Museum of Natural History; the
late Henry E. Crampt^m of Barnard College;
Peter Buck, Margaret Titoomb, Yoshio Kondo,
Eklward Br>'an and Donald M. Mitchell, all of the
B. P. Bishop Museum; Ruth E. Lee and Ann
Blum, Museum of (x)mparative Zoology, Harvard;
Spencer M. Tinker of the Waikiki Aquarium;
Albert Panning of the Hamburg Zoologischen
Staatsinstituts; Barbara Johnson of Princeton,
New Jersey; Yosihiko Sinoto of Huahine and
Aurora Natua of the Papeete Museum; and, for
assistance for 1961 travel expenses, the Explorers
Club of New York and the Frank M. Chapman
Memorial Fund of the American Museum of Nat-
ural History. Dean Amadon, R. Tucker Abbott
and many others gave of their time and
assistance, for which I am very grateful.

BIBLIOGRAPHIC REFERENCES

Andrew Garrett's Fische der Sudsee in Journal des
Museum Godeffroy, Hamburg 1873/7.5 Vol. 1 and 2, Vol.
3, 1909. written and edited by Albert C. L. G. Gunther.
Florence M. .Spoehr. White Falcon. Pacific Books. Palo
Alto. Calif. 196.3. pp. 101-119.

Ebenezer V. Cooper. "Obituary of Mr. Andrew Garrett"
in Journal of Conchology (Leeds) 1888, Vol. V: 317-318.
Also West American Scientist, vol. 4, p. 19.
Letter from A. G. to James M. Barnard, dated Hilo,
Hawaii, April 29, 1857. Original in M. C. Z.. Harvard
University.

Crew List of the Bark, Edward. Old Dartmouth
Historical Society, New Bedford. Mass.
77ie Friend. Honolulu, (newsiiaper) October 13, 18.58 p. 76
article. "Mr. Andrew Garrett, the Naturalist" by Samuel
C. Damon.

Baker, Ray Jerome, "Honolulu in 18,53", Honolulu, 19.50.
Letter from Dr. Wesley Newcomh to Garrett, Honolulu
Nov. 27, 18.54. Original in Bishop Museum Library.
Kay, A. E. "Biography of William Harper Pease in
Nemouria, Occasional Papers of the Delaware Museum of
Natural History, no. 16. Dec. .30. 197.5.
Garrett. Andrew letter to I/iuis .^gassiz. Hilo, Hawaii
.Jan. 29. 18.5.5. Original in M. C. Z. Harvard University.
Andrew Garrett to James M. Barnard, dated Hilo,
Hawaii Oct. 10, 18.5(). Original in M. C. Z.
The Friend, Honolulu (newspaper), July 1,5, 18.59 p. .52.
Letter from .John W. Ix>onard to his wife, on board ship
Lydia, March 2, 18.57. Original in po.ssession of Mrs. Bar-
bara Johnson, Princeton. N. J.

Letter from Louis Agassiz to J. M. Barnard (intended for
Garrett), from Cambridge. Mas.s. .■^ug. 28, 1S.57. Original
inM.C.Z.

Letter A. G. to J. M. Biirnanl. I'apai Puna, Island of
Hawaii,Julyl3,1857.

10.

11.

12,
13.

14.

15.

16. One of two undated letters from Agassiz, preserved in
the Andrew Garrett manuscripts in the Library of the
Bishop Museum. Honolulu, Hawaii.

17. Greene, K. W. Articles in Hawaiian Shell News. Issues
of April through October. 1960. Honolulu. Hawaii.

18. Mrs. James Warren. "The Morning Star": History of the
Chi Idrens "Missionary Vessel". Boston, 1860.

19. Letter from A. Garrett to J. M. Barnard containing his
Kingsmill Island Journal, dated Honolulu. Feb. 8, 1860.
Original in M. C. Z. Library. Harvard University.

20. Board of Trustees, Museum of Comparative 2yOology,
Harvard University. Cambridge, Mass. -fnl Annual
Report. 1862.

21. Andrew Garrett "The Terrestrial Mollusca Inhabiting
the Society Islands" Proceedings of the Academy of
Natural Sciences of Philadelphia. Journal 9, 1884-1888, p.
17-114.

22. Samuel C. Damon article in The Friend, Honolulu. Aug.
4, 1863. New Series Vol. 2, p. 8.

23. Andrew Garrett, letter to J. M. Barnard from Hilo,
Hawaii, April 29, 1857.

24. W. H. Pease, letter to A. Garrett, Honolulu. Sept 2, 1862.
Original in Bishop Museum Library.

25. Letter from W. H. Pease to A. Garrett, Jan. 20, 1864.
Original in Bishop Museum Library.

26. A. Panning. "Beitrage zur Geschichte des Zoologischen
Staatsinstituts und Zoologischen Museums in Hamburg."
Hamburg Dec. 1956.

27. Letter from J. C. Godeffroy to Theodor Weber, dated
Hamburg Jan. 25, 1867, copy provided to WST by his
descendant Caesar Godeffroy.

28. Judy Tudor, Editor and Compiler Handbook' of Fiji.
Fourth Edition. Pacific Publications. Sydney. N. S. W.
1972 p. 51, .53. .57.

29. Letter A. Garrett to Dr. W. D. Hartman, West Chester,
Pa., dated Huahine, Society Islands. Nov. 28, 1878.
Original in Carnegie Museum. Pittsburgh. See also The
Bejit of the Nautilus (R. T. Abbott ed.. 1976). p. 260. for a
similar letter written by W. D. Hartman to H. A. Pilsbry
about 1896!

.30. Information supplied by A. Panning of Hamburg 19.55 to

W. S. Tliomas.
.31. lietter fnim A. Garrett to J. G. Anthony. Cambridge,

Ma&s. Sept. 15. 1872 from Huahine. Original in MCZ

Library, Harvard University.
32. Introduction by Dr. A. C. L. Gunther to Fi.sche der

Sudsee. Hamburg, 1873.
.33. Memo from Alvin Seale M.D. in copy of his book "The

Golden Cloak" in Library of the Bernice P. Bishop

Museum, Honolulu.
31. l^elter from A. Garrett to W. D. HartniJin Feb. 10. 1879

in Carnegie Museum, Pittsbui'gh, Pa.

35. I/etter from A. Garrett to W. D. Hartman. dated
Huahine .June 2.5, 1887.

36. Cranipton, Henry E. "Studies on the Variation.
Distribution and of the Genus Partula". Carnegie In-
stitution, Washington. D.C, 1916,

37. Clench, William J. Conversation with W. S, Thomas,
Cambridge, Mass. Nov. 2, 1931.

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 29

THE NEMERTEAN, MALACOBDELLA GROSSA, IN THE OCEAN
QVAHOG, ARCTICA ISLANDICA (BIVALVIA)

Douglas S. Jones

Department of Geological and Geophysical Sciences
Princeton University
Princeton, N.J. 08540

ABSTRACT

JTie cornmetisal relationship between the marine bivalve, Arctica islandica, and
the nemertean Malacobdella grossa along the Atlantic coast of North America has
not heretofore been reported, although it has been documented in European
specimens. A single M. grossa was found living in a small Ocean Quahog dredged
from offshore New Jersey. In addition, the nemertean occurred in the venerid
clam. Pitar morrhuana,/rom the same locality with a frequency of 28%. Examina-
tion of numerous specimens of A. islandica /or M. grossa with negative results sug-
gests this occurrence is atypical.

The commensal nemertean, Malacobdella grossa
(Miiller), ranges widely along the North
American Atlantic coast where several species of
bivalves are known to serve as hosts. Coe (1943)
cites Mercenaria mercenana. Mya arenatia. and
Cras,^ost7ra virginica as known hosts of this com-
mensal. Porter (1962) added Mercenaria
campechiensis to this list, and Ropes discovered
M. gro.fsa in the Morrhua Venus, Pitar mor-
rhuana. The aforementioned species are among
seventeen bivalves known to serve as hosts for
the genus Malacobdella and fourteen for M.
grossa (Ropes, 1967).

While Coe (1943) lists Arctica islandica as a
host of Malacobdella grossa in European waters.
Ropes (1967) points out that in the western At-
lantic M. givssa is not known from either Arctica
islandica or Spisula solidissima, two widely dis-
tributed and abundant Middle Atlantic coast bi-
valves (Merrill and Ropes, 1969). This is unusual,
since Malacobdella occurs in two other species of
Spisula (S. sachalinensis from Japan and S
stultorum from Europe). Brunberg (1964), in re-
porting on nemerteans from Danish waters, says
Malacobdella grossa was commonly collected in
the mantle cavity of Cyprina (now Arctica) is-
landica in the areas investigated, i.e., the
Gullmarfjord, the neighborhood of Frederikshavn
and Laes^, in the northern J0resund. Nevertheless,

Ropes (1967) reports examining thousands of surf
clams and numerous ocean quahogs from the At-
lantic coast with negative results.

METHODS

Specimens of Arctica islandica were obtained
on 27 June 1977 by a commercial clamming vessel
fishing with a "hydraulic clam dredge at a loca-
tion ('^73°40'W and 40°15'N) approximately 32
kilometers offshore from Asbury Park, New
Jersey, in water 30 meters in depth. Several
specimens of Pitar motrhuana were caught with

FIG. 1. Arrows shmv the nemertean. Malacobdella grossa at-
tached to the mantle of the Ocean Quahog. Arctica islandica
after removing the left, valve and visceral mass. Scale at right
has centimeter divisions.

30 THE NAUTILUS

January 10, 1979

Vol. 93 (1)

the ocean quahogs in the same dredge hauls.
Twenty ocean quahogs of various sizes and 18
specimens of P. morrhuana were randomly
selected from the dredge hauls, opened in the
laboraton,'. and examined. Shell lengths were
measured and the soft body tissues searched for
other organisms. When the single nemertean,
MnlacdhdeUa groni^a, was discovered in an in-
dividual Arctica i'slandica, it was identified,
measured, photographed, and preserved.

RESULTS

A single specimen of Airtira Mandicn con-
tained the commensal nemertean Malacobdella
grossa living in its mantle cavity (Fig. 1). The
clam, a smaller individual than those normally
caught, had a shell-length of 55 mm. The nemer-
tean was easily recognized by the presence of a
ventral, rear sucker found attached to the mantle
of the clam, hi a relaxed live state it measured 21
mm in length. Of the eighteen specimens of Pilar
morrhuana collected from the same dredge haul,
five contained individuals of M. grossa for an in-
cidence of infection of 28%. Shell-lengths of the
Pitar specimens ranged from 39 mm to 58 mm
and averaged 44 mm while M. grossa occurred in
individuals ranging from 41 mm to 58 mm. The
worms ranged between 20 and 28 mm in length
and each host contained only a single nemertean.

DISCUSSION

The single occurrence of Malacobdella grossa in
an individual of Arctica islandica is apparently
very rare for the Atlantic coast of the United
States and Canada. Though Brunberg (1964)
found ocean quahogs commonly hosting M gmssa
in Danish waters, no incident of this relationship
has ever been reported on this side of the Atlan-
tic. Ropes (1967, personal communication) has ex-
amined numerous specimens of Arctica without
finding any evidence of infection by M. grossa. In
addition, I have opened almost one thousand
specimens of Arctica islandica and Spisula
solidissima for various research purposes without
encountering another nemertean.

The single infected clam was smaller than
those usually caught by commercial clamming ap-
paratus and hence smaller than those usually ex-
amined. It was similar in size to the infected in-
dividuals of Pitar morrhuana collected in the
same dredge haul. Nevertheless, numerous com-
parably-sized Arctica have been examined with
negative results. Examination of hundreds of
specimens of both surf clams and ocean quahogs
for M. grossa has, except for this one incident,
yielded negative results. The evidence supports
Ropes' (1967) conclusion that Malacobdella grossa
does not normally associate with either Spisula
solidissima or Arctica islandica along the Atlan-
tic coast of North America.

ACKNOWLEDGMENTS

I would like to thank Mr. John Ropes of the
National Marine Fisheries Service for critically
reading the manuscript and Dr. Donald Baird of
the Princeton Natural History Museum for
photographing the specimen. The cooperation of
Snow Foods. Inc. of Pt. Pleasant. N. J. is greatly
apprec-iated. This report is an outgrowth of other
work on neritic bivalves supported by NOAA Sea
Grant #04-6-158-44076 to Dr. Ida Thompson of
Princeton University.

LITERATURE CITED

Brunberg. L. 19&4. On the nemertean fauna of Danish waters.
Ophelia 1:77-111.

Coe. W. R. 1943. Biology of the nemerteans of the Atlantic
coast of North America. Trans. Cotmecticut Acad. Arts Sci.
35:129-328.

Merrill. A. S. and .J. W. Ropes. 1969. The general distribution
of the surf clam and ocean quahog. Pivc. Natl Shellfish.
Assoc. 59:40-45.

Porter. H. .1. 1962. Incidence of Malacobdella in Mercenaria
campechiensis off Beaufort Inlet. North Carolina. Pmc.
Nat I Shellfish. Assoc. 53: 133-145.

Ropes, J. W. 1%7. Malacobdella grossa in Pitar morrhuana
and Mercenaria campechiensis. The Nautilus 81:37-40.

. 1966. Pitar morrhuana, new host for

Malarobdetla grossa. The Nautilus 79:128-130.

Vol. 93(1)

January 10, 1979

THE NAUTILUS 31

DEPTH DISTRIBUTION OF THREE GASTROPODS IN NEW MISSION BAY.

LAKE MICHIGAN

Gary L. Pace, Ernest J. Szuch and Richard W. Dapson

Biolog>' Department, University of Michigan-Flint
Flint, Michigan 48503

ABSTRACT

SCUBA was used in August, 197^. to determine the depth-distribution of mails
at two localities in New Mission Bay, a small inlet of Grand Traverse Bay. Lake
Michigan. Five 0.5m^ samples were collected at 20 ft intervah along each of 6
depth contours at both localities (5. 10, 15. 20, 25. 30 ft and 10, 12.5, 15, 20, 25, 30
ft). At the 2 localities Gyraulus parvus (Say) attained peak densities of 2.U/m} and
28.Jt/m^ on small pebbles at 10 ft depths. These densities represent 60% and 92% of
the Gyraulus collected at the two localities. Most Marstonia decepta (Baker) fAm-
nicola lustrica of Pilsbry) and Valvata tricarinata (Say) were collected from sand-
silt .wbstrates. Both M. decepta and V. tricarinata reached their maximum den-
sities at the 10 ft depth at one locality (16i.8/m^ and 29.6/m^, respectively), and at
the 12.5 ft depth at the other (152.i/m^ and h9.2/m^, respectively). These densities
represent 60% and 5k%> of the M. decepta and 37% and 30% of the V. tricarinata
specimens collected fiv7n the two localities.

Most studies of Great Lakes' macrobenthos
have understandably been large scale dredging
operations dealing primarily with profundal
organisims (Eggleton, 1936, 1937; Mema, 1%0;
Powers and Robertson, 1965; Robertson and Alley,

FIG. 1. Location ofNew Mission Bay (mmicin inset).

1966; Henson, 1966) or with specimens collected
from the upper littoral zone and beach drift
(Goodrich, 1932; Heard, 1962a, 1962b; Henson and
Herrington, 1965). Beach drift specimens, of course,
tell us very little of the preferred habitat, and a
number of papers have demonstrated problems
with the reliability and efficiency of several types
of bottom samplers (Beeton, Carr, and Hiltunen,
1965; Milbrink and Wiederholm, 1973). ahers
have shown, however, that, visibility permitting,
SCUBA-assisted studies can provide direct, quan-
titative collections from a wide variety of
substrates (Cvancara, 1972; Harmon, 1972; Clam-
pitt, 1973, 1974). This paper reports on a SCUBA
study of the depth distribution of 3 littoral
gastropod species at 2 discrete localities in New
Mission Bay, a small inlet on the western side of
Grand Traverse Bay, Lake Michigan (Fig. 1).

New Mission Bay narrows irregularly from a
maximum width at its mouth of about 2.3 km,
due North for a distance of approximately 1.7 km
(Fig. 2). A paved road circumscribes the bay
within a few hundred meters at all points. Be-
tween the road and the bay, mixed coniferous-
deciduous woods dominate along the east shore
and alternate with cleared land on the west and

32 THE NAUTILUS

January 10, 1979

Vol. 93 (1)

FIG. 2. Cantimr map of New Mission Bay showing positions
of Oniena Beach and Oniena-T)ni'erse Yacht Club collecting
localities (adapted from U.S. Army Corps of Etiyiiieers Chart
LS. 706). Scale = ■5(X)ft/unit: Contour Interval = 6fi.

north shores. The very small town of Omena with
its marina and public beach rests at the bay's
Northwest comer while a few cottages, perma-
nent residences and a yacht club are scattered
among the trees along the east shore. The bot-
tom-slopes are ver>' gradual on both sides at the
outer end of the bay. On the western side of the
inner half of the bay, however, the bottom-slope
is at first very gradual and then drops off
abruptly. While there are local differences
discussed below, the northern and northeastern
bottom-slopes deepen rather regularly. Within
New Mission Bay, only one region in the north-
west corner is known to exceed 60 ft in depth
(Fig. 2). Temperature measurements of 21° C
down to 30 ft and 20° C at 40 ft were recorded in
the northeastern part of the bay on August 17,
1974. These correspond well with Lauffs (1957)
data for this region of (Jrand Traverse Bay.
Lauffs report also provides a Secchi disk trans-
parency measurement of 9-10 m and notes that sur-

face currents pass the mouth of New Mission Bay
in a WSW direction at this time of year.

MATERIALS AND METHODS

SCUBA was used to study the depth distribu-
tion of snails along two "transects" in New Mis-
sion Bay (Fig. 2). One, designated "Omena Beach"
(O.B.), runs south from a point about 100 yds east
of the public beach at the northern end of the
Bay. Here the bottom-slope increases gradually in
depth to about 15 ft and then drops off rapidly to
depths greater than 60 ft. The predominantly
sandy bottom gradually becomes overlain by a
thin layer of colloidal organic sediment as the
depth increases. The second transect, "Omena-
Traverse Yacht Club" (Y.C.), extends west from
the east shore about ,50 yds. south of the yacht
club. The bottom here is strewn with large boul-
ders at the edge and increases rapidly in depth to
about 10 ft where the substrate becomes sandy
and the slope levels off for 100-150 ft. Here the
organic content of the substrate increases as the
depth increases rapidly to more than 45 feet.
Macrophjtes were essentially nonexistant at both
study areas.

Each transect consisted of six 100 foot lines
marked at 20 ft intervals and placed approx-
imately parallel to shore along depth contours.
These were established at depths every 5 feet out
to 30 feet at Omena Beach, and 10 ft", 12.5 ft, 15
ft, 20 ft, 25 ft, and 30 ft off the Yacht Club.
Depths were determined using a calibrated line
tied to a float and were checked using diver's
depth gauges. A sand-filled "Hula-Hoop" was se-
quentially placed at the center of each 20 ft sec-
tion establishing a constant sample area (0.4KmM.
Hand-picked snails were placed into prelabeled
"zip-lock" type plastic bags. Thirty snail samples
were thus collected directly from each of the two
study areas.

RESULTS

The following mqllusks, in order of decreasing
maximum density (X/m'), were collected from the
two localities: Marstonia deceptn (Baker) (.4m-
nicola lustrica of Pilsbry) (164.8), Valrata
tricarinata (Say) (49.2), Gifraulus parvus (Say)
(28.4), Physa .sp. (3.6), Pisidium sp. (2.4), Cinciri-

Vol. 93(1)

January 10, 1979

THE NAUTILUS aS

TABLE 1. Depth Distribution <\f Snails near Omena Beach. Data are mean den^ties (^/m') nf 5 samples (n =.V at each depth,
with Standanl Enrrr (SE) in parentheses: % of the species-populatian at each depth: % nf the snail community at each depth
represented by each species.

Species

Depth

fx/m§f(SE)
0.0

%

%

(ft)
5.0

Species
0.0

Community

G. parvus (Say)

0.0

10.0

2.U ( 1.3)

60.0

1.2

15.0

0.0

0.0

0.0

20.0

0.8 ( 0.7)
0.8 ( O.k)

20.0

3.6

25.0

20.0

1.5

30.0

0.0

0.0

0.0

H. decepta (Baker)

5.0

7.6 ( 1.3)

2.8

40.4

(= A. lustrica Pllsbry)

10.0

164.8 (Ik.k)

59.8

83.7

15.0

W.it ( 5.2)

16.1

68.1

20.0

18.0 ( 2.0)

6.5

80.3

25.0

38.0 (14.;+)

13.8

72.5

30.0

2.8 ( 1.3)

1.0

67. 5

V. trlceirinata (Say)

5.0
10.0

11.2 ( 1.7)
29.6 ( 3.7)

14.1
37.4

59.6
15.1

15.0

20.8 ( 7.6)

26.3

31.9

20.0

3.6 ( 1.6)
13-6 ( 7.3)

4.5

16.1

25.0

17.2

26.0

30.0

0.4 ( 0.4)

0.5

12.5

natia cincinnatiensis (Anthony) (2.0), Goniobasis
livescens (Menke) (1.2), Lymnaea decampi
(Streng) (0.8), LampsUis mdiata .vliquoidea
(Barnes) (0.2), Anodonta graudis (Say) (0.1). Due
to the substantial differences in relative abun-
dance, only the data for the first three species are
presented (Tables 1, 2, Figures 3-6) in any detail.

Gip-aulus parvus, rarest of the three most
prominent species, was most commonly found on
the sand-gravel substrates at 10 ft in both

localities. Densities of 2.4/m^ and 28.4/m^ repre-
sent 60% and 92.2% of the specimens collected at
O.B. and Y.C., respectively (Tables 1, 2). Thus, at
10 ft, Gijraulus represented only about 1% of the
3-species community at O.B., but as much as 30%
of that community at Y.C. The distribution of
Marstonia decepta at Omena Beach (Table 1, Fig.
3) appears bimodal, with a major peak at 10 ft of
164.8/m^ and a minor one of 38/m^ at 25 ft. At
the Yacht Club locality (Table 2, Fig. 4), however,

TABLE 2. Depth Distribution of Snails near Omena-Traverse Yacht Club. Data are mean densities (X/m^) of 5 samples (n=.5)
at each depth, with Standairl Error (SEj in parentheses: % of the species-population at each depth: % of the snail cornmunity at
each depth represented by each speciex.

% %

Species

Depth

Dens]

ty

(ft)

10.0

(X/m2)

28.4

(SE)

G. parvus (Say)

7.8)

12.5

0.4

0.4)

15.0

0.4

0.4)

20.0

0.8

0.7)

25.0

0.4

0.4)
0.4)

30.0

0.4

H. decepta (Baker)

10.0

60.4

6.1)

(=A. lustrica Pilsbry)

12.5

152.4

11.7)

15.0

46.8

12.1)

20.0

11.2

2.2)

25.0

8.8

2.7)

30.0

4.0

1.8)

V. tricarinata (Say)

10.0

5.2

0.9)

12.5

49.2

6.8)

15.0

29.6

4.8)

20.0

38.0

4.6)

25.0

27.2

6.9)
4.4)

30.0

12.4

Species

Community

92.2

30.2

1.3

0.2

1.3

0.5

2.6

1.6

1.3

1.1

1.3

2.4

21.3

64.3

53.7

75. '^

16.5

61.0

4.0

22.4

3.1

24.2

1.4

23.8

3.2

5.5

30.5

24.4

18.3

38.5

23.5

76.0

16.8

74.7

7.7

73.8

34 THE NAUTILUS

January 10, 1979

Vol. 93 (1)

200,

150.

/ m

100

50

I

M. dec ept a

tt

01 I I I I

5 10 15 20 25 30

4=.

ft

FIG. 3. Depth distributimt of Marstonia decepta at Omena
Beach. Horiznnal Line = X/m': Vertical Bar = ± 1 Standard
Error; Vertical Line = Range of density among 5 samples at
each depth.

Marstonia shows a definitely unimodal distribu-
tion with a maximum density of 152.4/m^ at 12.5
ft. These ma.ximum densities represent nearly
60% of the Omena Beach specimens and almost
54% of the Yacht Club specimens taken from the
6 depths at each locality. Marstonia was obvious-
ly the dominant member of the molluscan com-
munities of the 5 deeper stations (68-87%) at O.B.
(Table 1) and of the 3 shallower stations (61-75%)
at Yacht Club (Table 2).

Valvata tricarinata appears to demonstrate
bimodal distributions at both localities, but with
distinct maxima in each case. At Omena Beach
(Table 1, Fig. 5), Valvata reached its peak density
of 29.6/m^ at 10 ft. After decreasing rapidly from
20.8/m^ at 15 ft to 3.6/m^ at 20 ft, Valvata in-
creased again to 13.6/m' at 25 ft. A similar, but
less dramatic bimodal distribution was found at
the Yacht Club site (Table 2, Fig. 6). Here, the
maximum density (49.2/m') occured at 12.5 ft.
This declined to 29.6/m' at 15 ft and increased

again to 38.0/m^ at 20 ft. The maximum densities
represent only about 37% of the specimens col-
lected at Omena Beach and less than 31% of the
specimens taken at the Yacht Club site. V.alvata
was the dominant member of the communities of
the 5 ft station at Omena Beach (Table 1) and of
the 3 deeper stations off the Yacht Club site.
(Table 2).

DISCUSSION

The paucity of similar studies prevents the
direct comparison of these data with those of
others and the causes for the demonstrated
stratification can only be surmised. Since all sta-
tions were within the elipimnion, the chemistry
of these environments would be expected to be
rather homogeneous. Physico-chemical differences
in the benthic microhabitats, if they e.xist, may
therefore be assumed to be the direct result of
substrate-biota interactions. Harman (1972),
reporting on mollusks from three central New
York lakes, suggested that definite relationships

-200.

X/2

/m

•>'»<■.

M. dec epia

150.

1

100.

50.

^^

f

0.

+ 4-1

10

15 20 25
ft

30

FIG. 4. Depth distribution of Marstonia decepta at Omena-
Traverse Yacht Cluh.

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 35

exist between mollusk distribution and substrate
patterns. The substrates of ail our stations fall
into one of his five broad types: "Littoral silt and
detritus -fine organic and inorganic materials."
According to Harman, this is the preferred sub-
strate of only one of our three species, namely
Valvata tricarinata. The other two species,
Gip-aulus panms and Mastnnia decepta are said
to prefer "Autochthonous organic matter - aquatic
plants and their decaying remains."

Of 121 collections of Gip-avbis [mrvus by Har-
man (1972), 94 were from substrates of auto-
chthonous organic matter, while only 9 were from
littoral silt and detritus. Considering that there
were no aquatic macroph>1:es near any of the sta-
tions we studied, it is perhaps surprising the
Gyranlus were found to represent as much as
30% of the molluscan community at the 10 ft
depth of the Yacht Club locality. This was,
however, the only station in which Gip'aulus was
at all common. As indicated above, Gyrmdus was
frequently collected from small pebbles rather
than from the more abundant sand and flocculent
organic sediments. This may reflect the require-
ment of a more stable substrate usually available
in the form of higher aquatic plants in these
snails' preferred habitats.

Three observations suggest that major com-
ponents of the niches of Marstonia decepta and
Valvata tricarinata overlap: (1) the occurrence of

60,

4 0

y,

V2

20

V. tricarinata

I

t

11

5 10 15 20 25 30

ft

FIG. 5. Depth distribution of Valvata tricarinata at Omena
Beach.

80.

60

X/ 2 ''O
/m

20.

V. tricarinata

W

\\\

-f

+

5 to 15 20 25 30

ft

FIG. 6. Depth distribution of Valvata tricarinata at
(hnertn-Tnwerse Yacht Club.

both species at all our collecting stations; (2) the
co-occurrence of the peak densities of these two
species at 10 ft (O.B.) and 12.5 ft (Y.C.) indicating
the preferred conditions for both species; (3) the
co-occurrence of secondary density peaks at the
25 ft depth at O.B. That Marstonia is better
adapted to the conditions in New Mission Bay is
indicated by the fact that it was the dominant
species in 8 of the 12 communities studied. Since
a higher percentage of the Marstonia specimens
were collected at the 10 ft (60%) and 12.5 ft (54%)
depths, we might infer that this species has a
stronger preference for (i.e., is better adapted to
the) conditions at these depths than is Valvata
(37% & 31%). At neither location did Valvata
(15% & 24%) dominate the communities of these
depths. At Omena Beach, Valvata dominated only
the 5 ft depth, while Marstonia dominated all 5
greater depths. Off the Yacht Club however, Mar-
stonia donated all three shallower depths, while
Valvata was obviously the dominant member of
the three deeper communities. Thus it seems that
Marstonia is not only generally better adapted to
the New Mission Bay conditions, but specifically
best adapted to those at the 10-12.5 ft depths.
Valvata, on the other hand, seems less spe-
cialized, but better able to take advantage of the

36 THE NAUTILUS

January 10. 1979

Vol. 93(1)

marginal habitats where Marstonia densities are
low (5 ft-O.B.; 20, 25. 30 ft - Y.C.). Thus Mar-
stonia decepta often outnumbers Valvata tricar-
inata in a littoral silt and detritus habitat. This
directly contradicts Harman's (1972) statements
as to the substrate preferences of these two spe-
cies, and demonstrates the care which must he
observed when attempting to apply the findings
of those working on inland lakes in contrast t<i
those dealing with the ecology of the Great
Lakes.

ACKNOWLEDGMENTS

The authors express their deepest appreciation
to Dr. Lee H. Somars. Director, Underwater
Technology Laboratory and the Michigan Sea
Grant Program for providing technical assistance,
as well as the compressed air required for 200
man-hours of underwater work carried out dur-
ing this study. The cooperation of the Omena-
Traverse Yacht Club is also gratefully acknow-
ledged. In addition, the assistance of our research
assistant, Gregory Panos, III, and student
assistants John Kerr and Larry Stevens was essen-
tial to the completion of the underwater sampling.
This research was supported by a grant from the
University of Michigan-Flint Faculty Research
and Special Projects Committee.

LITERATURE CITED

Beeton, A. M., J. F. Carr, and J. K. Hiltunen. 1965. Sampling
efficiencies of three kinds of dredges in southern Lake
Michigan. Great Lakes Res. Div.. Univ. Mich.. Puhl. 13: 209.
(Abstr.)

Qampitt, P. T. 1973. Substratum as a factor in the distribu-
tion of pulmonate snails in Douglas Lake, Michigan.

Mdncihyia 12: .■?79-399.
1974. Seasonal migratory cycle and related

movements of the fresh-water pulmonate snail, Physa In-
tegra. Amer Mull. .Xattir. 92: 27.5-300.
Cvancara, A. M. 1972. Lake mussel distribution as determined

with SCUBA, fi-o/oyy 53: 1.54-1.57.
ICggleton, F. E. 19:36. The deep-water bottom fauna of

Lake Michigan . Papers Mich. Acad. Sci. 21:.599-612.
19.37. Productivity of the profundal benthic

zone in Lake Michigan. PapcrsMich. Acad. Sci. 22: .593-611.
Goodrich, C. 19.32. The Mollusca of Michigan. Univ. Mich.

Miiseum Zool. Handbimk Series 5: 1-120.
Harman, W. N. 1972. Benthic substrates: their effect on

fresh-water Mollusca. Ecnhigy 53: 271-277.
Heard, W. H. 1962a. The Sphaeriidae (Mollusca: PelecyTxxla)

of the North American Great Lakes. Amer. Midi. Naiur.

67: 194-198.
1962b. Distribution of Sphaeridae (Pelecypoda)

in Michigan, U.S.A. Malacaloyia 1: lXi-161.
Henson, E. B. 1966. A review of Great Lakes benthos research.

Great Ijikeli Res. [Hr.. Univ. Mich.. Piihl. 14: 37-54.
Henson. E. B. and H. B. Herrington. 196.5. Sphaeriidae

(Mollusca: Pelecjiwda) of Lakes Huron and Michigan in the

vicinity of the Straits of Mackinac. Great Lakes Res. Div.,

Univ. Mich.. PiM. 13: 77-95.
Lauff, G. H. 1957. Some aspects of the physical limnology of

Grand Traverse Bay. Great Lakes if&s. Div., Univ. Mich.,

PHbl.2: 1-.56.
Merna. J. W. 1960. A benthological investigation of Lake

Michigan. MS Tliesi.'i. Michiyan State Univ. 74 pp.
Milbrink, G. and T. Wiederholm. 197.3. Sampling efficiency of

four types of mud bottom samplers. Oikus 24:479-482.
Powers, C. F. and A. Robertson. 1965. Some quantitative

aspects of the macrobenthos of Lake Michigan. Great Lakes

Res. Div., Univ. Mich. Ptihl. 13: 153-1.59.
Robertson, A. and W. P. Alley. 1966. A comparative study of

Lake Michigan macrobenthos. Limnology and Oceanography

11: .576-583.

ARION SUBFUSCUSm SOUTHEASTERN MICHIGAN

Dorothy Blanchard

2014 (leddes Avenue

Ann Arbor, Michigan 48104

and

Lowell L. Getz

Department of Ecologv', Ethology and Evolution

University of Illinois, Urbana, Illinois (ilSOl

The North American distribution of the in-
troduced European slug, Ariati t^ubfiisais
(Draparnaud), has been described by Chichester

and Getz (1968. 1969). Getz and Chichester (1971)
and Getz (1974). In general, the species occurs
throughout northeastern United States and

Vol. 93(1)

January 10, 1979

THE NAUTILUS 37

southeastern Canada, in the vicinity of Washing-
ton, D. C, and in the Kipawa Reserve in eastern
Canada. The latter record represents the furthest
westward locality previously known for the
species. A recent discovery of A. mbfuscus in
Ann Arbor and Allen Park, Michigan, is there-
fore worthy of note. It extends the known range
of the species to include the Great Lakes region.

Specimens of the species were first found by
the senior author in her yard located within the
city limits of Ann Arbor. Subsequent investiga-
tions revealed the species to be present in some,
but not all, adjacent yards, as well as in Allen
Park, a suburb of Detroit. It has not been re-
ported elsewhere in the Ann Arbor or Detroit
area, however. All individuals collected were
bright orange and resemble Color Form Three as
described by Qiichester and Getz (1969).

The Blanchard's yard contains extensive un-
cultivated planting of native and introduced
species of herbaceous plants, shrubs and trees.
Arion fasciattis (Nilsson) has been present in the
yard for years, but .4. ftuhfmcus was first noticed

in 1973. It is not known how the species became
established in Ann Arbor; most dispersal of
European slugs apparently occurs during trans-
jiort of nursery stock (Chichester and Getz, 1969).
In all regions except Michigan and Washington,
D. C, A. subfuscus occurs in natural woodland
habitats as well as in association with human
habitation. Chichester and Getz (1969) have
predicted that A. subfusctts will become
established in natural habitats throughout most
of North Central United States and South Cen-
tral Canada.

LITERATURE CITED

Chichester. L. F. and L. L. Getz. 1968. Terrestrial slugs. The

Biologist 5<i:14S-im.
. 1969. The zoogeography and ecology of arionid

and limacid slugs introduced into Northeastern North

America. Malacologia 7:313-.346.
Getz. L. L. 1974. Arion .mbfuscus in the vicinity of

Washington, D. C. The Nautihts 88:66.
Getz, L. L. and L. F. Chichester. 1971. Introduced Slugs. The
Biologist 53:118-12:1.

THE ASIATIC CLAM, CORBICULA MANILENSIS,
FROM TWO RESERVOIRS IN EASTERN TEXAS.

David Pool and Jack D. McCullough

Department of Biology

Stephen F. Austin State University

Nacogdoches, Texas 75962

Specimens of the Asiatic Clam, Corbicula
manileriftis (Philippi), were collected on several
dates during 1977 from Lake of the Pines Reser-
voir in the Big Cypress River Basin, Texas, and
from Murvaul Reservoir in the Sabine River
Basin, Texas. The species has not been previously
reported fi'om either reservoir. Specimen at Lake
of the Pines Reservoir were collected approx-
imately one kilometer from the dam at a depth of
less than one meter, on substrates of sand, fine
gravel and very hard packed red clay. Collections
at Mur\aul Reservoir were made approximately
100 meters from the dam in a substrate of sand,
at water depths also not greater than one meter.
While the population densities of the clam were
great in both reservoirs, the largest numbers
were found at a depth of approximately one

meter during the summer months, and at the
water's edge during the winter months.

The mean values for physico-chemical para-
meters determined during 1977 (Table 1.) indi-
cate both reservoirs have good water quality,
and the fertility of both bodies of water are
classed as mesotrophic. Preserved specimen have
been deposited in the Invertebrate collection at
Stephen F. Austin State University.

TABLE 1. Meciri values for physico-chemical parameters re-
corded for Lake of the Pines and Murvaul Reservoirs
during 1977.

^^

NO3-N
(PPM)

PO4
(PPM)

02

(PPM)

NH3-N
(PPM)

CI

(PPM)

Turbidity
(NTU)

(PPM)

Ca
(PPM)

Murvaul

0.10

0.09

7.4

0.42

23.1

8.7

19.5

4.1

Lake of
the Pines

0.0«

0.44

6.8

0.51

19.2

1.9

22.8

9.4

38 THE NAUTILUS

January 10, 1979

Vol. 93(1)

EVIDENCE FOR TIDALLY CORRELATED FEEDING RHYTHMS
IN THE EASTERN MUD SNAIL, ILYANASSA OBSOLETA

J. Roy Robertson

University of Georgia

Marine Institute

Sapelo Island, Georgia 31327

ABSTRACT

The occurrence of the crystalline style in an intertidal population of the mud
snail, Ilyanassa obsoleta, 7vas found to be correlated mth the stage of the tide. At
bnv tide irhen the snails were exposed almost no individuals sampled possessed
styles, while during high tide when the snails were covered almost all individuals
sampled possessed styles. The presence or absence of a style occurred concomi-
tantly with the presence or absence of fond in the digestive tract. These observa-
tions suggest that I. obsoleta individual can possess cyclical, discontinuous feeding
rhythms, .'similar to those that have been observed in intertidal bivalves and one
other gastropod species.

The digestive processes of certain intertidal
bivalve species and the marine pulmonate
gastropod, Amphibola crenata, from New
Zealand, have been shown to be cyclical and cor-
related with the state of the tide (Morton 1956;
Morton 1971, 1973 1975a, 1975b, 1977; Bernard
1973; Langton and Gabbott 1974). In particular,
the studies on intertidal bivalves have shovra that
the crystalline style dissolves when the animals
are exposed at low tide and reforms when they
are subsequently inundated. Although the mud
snail, Eyanassa obsoleta (Say), is a member of the
typically carnivorous, rachiglossan Gastropoda, it
is primarily a deposit feeder (Scheltema 1964). As
an adaptation to this mode of foraging, /. obsoleta
possesses a crystalline style which aids in the
digestion of microflora inhabiting the ingested
substrate (Brown 1969). This note presents
evidence for the cyclical dissolution and reforma-
tion of the crystalline styles belonging to
members of an intertidal population of /. obsoleta
in southeast Georgia.

Contribution No. 380 from the University of Georgia
Marine Institute.

MATERIALS AND METHODS

On November 18 and 19, 1977, /. ob.wleta in-
dividuals were collected during various tidal
stages in a slough located on the eastern side of
Sapelo Island, Georgia. Appro.ximately the same
tidal level of the shore was sampled at each
sampling period. The maximum depth of water
during subtidal sampling periods was 30 cm.

Sampling was done by placing a line, marked
at one meter intervals, parallel to the shore line.
At randomly selected intervals 10 X 10 cm,
square quadrats were inserted into the substrate.
All of the snails, buried or on the surface, were
removed from each quadrat sampled. Enough
quadrats were sampled so that the total number
of snails collected at each sampling period ex-
ceeded 50. Fifty snails were immediately selected
at random from the main sample. Each specimen
was processed in the field according to the follow-
ing protocol: 1) shell length was determined, 2)
snail was carefully removed from its shell by
fracturing the shell with a portable vise, 3) style
sac was opened with fine forceps and the
presence or absence of a style was noted, 4) snail
was placed in vial containing acid Bouin's fix-

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 39

ative. The total time from collection to final pro-
cessing did not exceed 45 minutes. The contents
of the digestive tracts of preserved snails were
determined later in the laboratory.

RESULTS AND DISCUSSION

Figure 1 shows that the occurrence of the
crystalline style in the study population is
definitely correlated with the tidal cycle. Diel
variations in temperature and light do not ap-
pear to modif>' this correlation. Air temperatures
ranged fi'om 24°C in the daytime to VZ'C just
before sunrise while water temperatures varied
between 19° - 15°C. The lengths of the snails
sampled ranged from 17-21 mm, indicating that
the population under investigation comprised on-
ly mature adults (Scheltema 1964).

The presence of the crystalline style in /. ob-
soleta is correlated with the type of food eaten
(Brown 1969). The style is absent in snails
feeding actively on the flesh of animals while it
is invariably present in those snails ingesting
sandy or muddy substratum. In this study all of
the snails with styles had mud present
throughout their digestive tracts while the caecae
and style sacs of the snails which did not possess
styles were devoid of any type of food. In some of
the latter snails, mud was found in the posterior
portions of the intestine and the rectum.

100-
90-

I 50

* 40-

i =0

z

w 20-

Mvai of tranMci

I I I I

leoo zooo

^tH — I — I — I — I I 1

2200 2400 0200 0400 0600 0800

FIG. 1. Occurrence of the crystalline style in an intertiiM
population of Dyanassa obsoleta. Upper curve represents tidal
cycle urith horizontal line indicating position of sampling
tnmsect relative to tide. Arrows indicate time sample taken.

Thus the correlation of the occurrence of the
crystalline style with the tidal cycle in the
population investigated appears to reflect
cyclical, discontinuous feeding activities similar
to those noted previously for bivalves and the
mud-dwelling, marine pulmonate, Amphibola
erenata. The results of the present study comple-
ment those showing that the locomotor activity of
/. obsoleta is ma.ximum during periods of high
tide and minimum during periods of low tide
(Stephens, Sandeen and Webb 1953).

While this study was restricted to a single
population of mud snails and one sampling date,
it does show that /. obsoleta individuals can
possess discontinuous feeding rhythms correlated
with the tidal cycle. Further work needs to be
done on the seasonal variability of foraging
rhythms (Morton 1975b, 1977) as well as the ef-
fects of substrate type, resource density and size
of individual on feeding patterns.

It is interesting to note that the feeding cycle
of the marine pulmonate, Amphibola erenata, is
qualitatively different from that of /. obsoleta.
While the latter restricts its feeding activities to
periods when it is covered by the tide, Amphibola
forages primarily during low tide or high tides
occurring at night (Morton 1975b). These dif-
ferences may reflect different adaptations to
predation by visually orienting predators which
follow the incoming tide (e. g. crabs and fish).
The lack of operculum may make it adaptive for
Amphibola to bury in the substrate when aquatic
visual predators are most active (high tide during
the day).

Ilyanassa, on the other hand, possesses both a
durable shell and an operculum. These attributes
might provide sufficient protection from preda-
tion to allow the snail to forage when aquatic
predators are active. The factors limiting the
' foraging activity of Eyanassa to periods when
they are covered with water may be desiccation
stress (Schaefer, Levin and Milch 1968; Schaefer,
Milch and Levin 1968) or the need to ingest a
substrate with a sufficiently high moisture con-
tent to facilitate digestion.

40 THE NAUTILUS

January 10, 1979

Vol. 93 (1)

I

LITERATURE CITED

Bernard. F. R. 1973. Crystalline style formation and function

in the oyster Cras.tostren giyax (ThunberR. 119^). <>}iheli<i

12:1.59-170.
Brown, Stephen C. 1969. The structure and function of the

digestive system of the mud snail Nassarim obsolettis (Say).

Malacoloyia 9: -147-500.
Langton. R. W. and P. A. Gabbott. 1974. The tidal rhythm of

extracellular digestion and response to feeding in (htrea

edulis L.Mnr. Rml 24:181-187.
Morton. B. S. 1971. The daily rhythm of feeding and digestion

in (Mri'a tdulis. Binl. Jaur. Linn. Sik: 3:329-:M2.
. 197.3. A new theop,' of feeding and digestion in

filter -feeding Lamellibranchia. Afoyacvi/oi/ia 14:63-79.

. 197.58. The diurnal rhythm and the feeding

responses of the Southeast Asian mangrove bivalve, Gelmna
proxima Prime 1864 (Bivalvia: Corbiculacea). Forma et
Futwtio 8:405-418.

. 197.5). The seasonal variation in the feeding and

digestive cycle of Amphibola crenatn (Martyn 1784)
(Gastropoda: Pulmonata). Forma et Functio 8:17.5-190.

_. 1977 The tidal rhvthm of feeding and digestion

in the Pacific oyster, Crassiostrea gigas (Thunberg). Jour.
Krp. Mar. Biol. Ecol. 26:135-141.

Morton, J. E. 19.56. The tidal rhythm and action of the
digestive system of the lamellibranch iMsaea rubra. Jour
Mar. Biol. Ass. U. K. 35:.563-.586.

Schaefer, C. W., Peter Milch and N. L. Ixjvin. 1968. Death
from desiccation in the mud-snail. Sassanus ohsoletus: ef-
fect of temperature, ne Nautilus 81: 109-1 14.

Schaefer, C. W., N. L. Levin and Peter Milch. 1968. Death
from desiccation in the mud-snail. NassariiLs ohsoletus: ef-
fects of size. The NautUw^ 82:28-31.

Scheltema. Rudolf S. 1964. Feeding habits and growth in the
mud-snail Nassarius obsolet us. Chesapeake Sri. 5: 161 - 166.

Stephens, G. C, M. I. Sandeen and H. M. Webb. 19.53. A per-
sistent tidal rhj-thm of activity in the mud snail A'a.s,sa ob-
soleta.Anat.Ker. 117:635.

FOOD SOURCES FOR ANACHIS AVARA (COLUMBELLIDAE)
AND A DISCUSSION OF FEEDING IN THE FAMILY

Edward B.Hatfield'

Rosenstiel School of Marine and Atmospheric Science

4600 Rickenbacker Causeway

Miami, Florida 33149

ABSTRACT

Lrnfjth meaavrements were made on indii'idiiah o/ Anachis avara maintnined in
the laboratory on carrion, epihiota from neaip-asfi blades. o}yanics in the sediment,
and on organics from a flow-through neawater system as a control. Snails grew
52% as much on epibiota as on canion, and showed some growth with sediment or
water column organics as their food. Epibiota are probably a significant souive of
food for A. avara in the field.

References regarding feeding in columbellid
gastropods show varied and sometimes contradic-
tory results (Puffer and Emerson 1953; Moore,
1%1; Marcus and Marcus, 1962; Bandel, 1974).
This paper reports differences in growth for

' Present address: Jackson E^uarine Laboratory. University
of New Hampshire, R.F.D. #1, Adams Point. Durham, New
Hampshire 03824.

Anachis avara (Say) on three separate food
sources, and reviews the available literature on
columbellid feeding.

METHODS

Two hundred and forty Anax;his avara were
collected from a turtle grass, Thalassia
testudinum (Konig). flat at Bear Cut, Miami,

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 41

Florida, during June, 1975. These individuals
were measured and placed in eight 19-liter
aquaria with running salt water. Two replicates
were maintained with carrion (C), turtle grass
with its epibiota (E), and particulate organic
matter and detritus in sediment (D), as food
sources, with the slight supply of particulate
organic matter in the flow-through water used as
control (W). No attempt was made to measure
the amount of food provided or the amount of
organic matter entering with the running water.
It was assumed that the 120 grass blades and the
4 cms. of sediment in the separate pairs of
aquaria provided the relative amounts of their
associated foods available in the habitat. The tur-
tle grass and sediment were changed weekly. Car-
rion was provided twice weekly for six-hour
periods, and all eight aquaria were cleaned
thoroughly at weekly intervals. The length of
each snail was measured to the nearest 0.01 mm
with vernier calipers every fourteen days for a
period of six weeks. Differences between mean
sizes were tested by a two-level nested ANOVA
at the 0.05 alpha level and by the Student-
Newman-Keuls non-parametric test (Sokal and
Rohlf, 1969).

RESULTS

Table 1 shows no difference in mean lengths of
the snails in the eight aquaria at the beginning
of the experiment. After 28 days, three separate
groupings by mean size were recognizable. Snails
which were fed carrion grew the most; those fed
grass blade epibiota grew next best; and those fpd
sediment organics and detritus grew the least,
the latter being grouped with the snails from the
control aquaria. The differences in size which oc-
curred are shown in Figure 1. Significant results
from this experiment are that: 1) growth oc-
curred in all tanks, including the controls where
the only food source was particulate organic mat-
ter entering through the flow-through seawater
system ; 2) snails feeding on the epibiota from the
grass blades grew 52% of the amount that snails
feeding on carrion did. Depending on relative
availability of epibiota and carrion in the field,
this latter result suggests that these epibiota are
an important food source for .4. avara in seagrass
habitats.

TARLE 1. Mean iemjth (mm) «/ Anachis avara and renults of
a Studcnt-Newman-Ki'iiU analyxif offeediiuj. Tlic fond types
connected by each bar contain snaih of the name statistical
mean length.

Time

(days) Length (mm)

E2
5.17

El
5.15

W2
5.10

Wl
4.98

D2
4.96

Dl

4.86

C2

4.81

CI
4.73

C2
6.85

CI
6.40

CI

8.06

CI

9.50

El
6.13

El
7.23

El
7.68

E2
6.03

Dl
5.56

Wl
5.27

W2
S.15

D2
5.09

C2
8.29

C2

9.61

E2
7.19

E2
7.61

Dl
6.06

Wl
5.81

D2
5.68

Dl
5.76

Wl
5.61

W2
5.27

W2
5.25

D2

*

C = carrion; E = epibiota; D = detritus; W = organics
from seawater (controls); * = no data; 1 & 2 = replicates of
each food type.

DISCUSSION

Several food sources are available to Anachis
avara at Bear Cut. Many of the mean 3291
seagrass blades per m^ are encrusted with various
kinds of epibiota (Humm, 1964; Meyers et ai,
1965; and personal observations). These epibiota
include polychaetes, hydroids, tunicates, sponges,
bryoza, and protozoa, as well as diatoms, blue-
greens and several species of red, green, and
brown macroalgae. No attempt was made to dif-
ferentiate between epifauna and epiflora as food
sources for Anachis avara. Carrion, such as dead
spider crabs, fish, and the large bivalve, Atrina
riyida. was visibly entrapped in the sediment.
Particulate organics and detritus were also pre-
sent in the habitat substratum.

10.5

C =

Carrion

E =

Epibiota

C

^...

D =

Detritus

^^

■J 8.5 .

W =

Control

^^

LENGTH
en

^^

""^ E

D

W

4,5

^'*—

0 14 28 42

TIME (days)

FIG. \. Mean lengths (mm) of Anachis avara fur two
replicates of each of three food types and a control.

42 THE NAUTILUS

January 10, 1979

Vol. 93(1)

The amounts and availability of the different
f(x)d sources of Anachis avara at Bear Cut prob-
ably differ. A. avara is the only abundant
sizeable gastropod prazer at Bear Cut, aside from
the micromollusks, Bittium varium, Tricolia af-
finis, and several species of Caecum. Only occa-
sional individuals of other columbellid species or
other gastropods such as Turbo castaneus or
Astraea americana were collected. Therefore,
although some overlap in food choice may exist
between A. avara and species from other phyla,
such as caridean shrimp, competition for the
epibiota is not thought to be intense. The high
productivity and continuous presence of epibiota,
and the probable low competition for this fauna
and flora, make this source of food highly
available to A. avara.

Carrion is also available to Anachvi avara, but
it is also consumed by swimming crabs, Calli-
nectes sapidus and Callinectes oniatu.% juvenile
spiny lobsters, Panularus argus, stomatopods,
several species of fish and other faunal groups. I
placed pieces of the bivalve, Chione cancellata, in
the habitat and witnessed several Callinectes cap-
ture them prior to observable reaction by A.
avara. Particulate organic matter from the sea-
water and sediment is also available; however,
results of the laboratory experiment suggest this
is only a minimal source of food.

Anachis avara probably feeds opportunistically,
and this may be typical of many species of the
family Columbellidae. In the laboratory-, I have
seen Anachis avara feed on moribund Tagelus
divims, a small gaping bivalve, but not on
tightly-closed Tellina texana or Macoma cenna.
Scheltema (1969) maintained Anachis avara on
clam meat in the laboratory. Puffer and Emerson
(1953) reported Amwhis avara semiplicata from
an oyster reef off central Texas as a herbivore.
Moore (1961) suggested that Anachis avara from
Port Aransas, Texas, preys on young oysters.
Because Anachis avara does not extend from the
Atlantic into the Gulf of Mexico (Scheltema,
1968; and Radwin, 1977), the species reported by
Puffer and Emerson (1953) and Moore (1961) is
probably Anachis semiplicata (Radwin, 1977: and
Moore, pens. com.). However, the status of the
western Gulf of Mexico species is not clear
(Scheltema, 1968). Individuals of Anachis

semiplicata from Sarasota, Florida, and of
Anachvi avara from Bear Cut lived and spawned
in the laboratory on a diet of clam and fish meat.

Differences in foods reported for several col-
umbellid species are partly the result of in-
complete feeding investigations and secondary
reports. Marcus and Marcus (1962) found algae in
the gut of Columbella mercatoria. Bandel (1974)
reported spawning for individuals of this species
maintained in the laboratory on both algae and
fi.sh meat. I saw capsules produced in aquaria by
individuals of this species that had been fed clam
and fish meat exclusively. I also saw Columbella
rmticoides spawn in the laboratory on the same
clam and fish meat diet. Marcus and Marcus
also found algae in the gut of this species.
Miller (1974) stated that most columbellids are
attracted to dead and/or injured prey, although
members of the genus Columbella probably eat
primarily plant material. The conclusion from
Marcus and Marcus (1962) that the two above
species of Columbella are solely herbivorous is
not correct.

From a detailed study of the anatomy of eight
columbellid species, Marcus and Marcus (1962)
included that as a group the columbellids are
general feeders. Marcus and Marcus (1962) found
recognizable parts of polychaetes, Crustacea, and
colonial ascidians in the alimentary tract of six
species of columbellids. Raeihle (1969) stated that
newly hatched Nitidella ocellata (now Mitrella
ucellata (see Abbott, 1974)) and an unidentified
Anachis sp. fed on crushed Mytilus edulis spat.
Bandel (1974) reported that Nitidella laevigata
eats Sargassum as well as meat; that Mitrella
argus and Anachis obesa eat hydroids but also
feed on pieces of clam and fish meat; and that six
other columbellid species feed on fresh meat in
the laboratory. Spight (1976) mentioned that
some columbellids feed on freshly killed crabs,
limpets, and chitons in the laboratory-. I have also
maintained Mitrella ocellata Mitrella bmata,
and Nitidella moleculina in the laboratory on
fresh meat from several species of fish and
bivalves. Fretter and Graham (1962) point out
that the superfamily Buccinacea is carrion-
feeding, rather than predatory, as its members
have lost the accessory salivary glands and boring
organ necessary for that activity. In general.

Vol. 93(1)

January 10, 1979

THE NAUTILUS 43

foods among the columbellids vary and it is prob-
able that at least some species utilize varied plant
and animal sources.

As no analysis was made of what Tlmla.'^Kia
epibiota or sediment organics and/or detritus
that Anachis avara fed on during the laboratory
experiment, it cannot be concluded whether this
species is carnivorous or omnivorous. Leathern
and Maurer (1975) refer to this species as a car-
nivore, but they reach this conclusion from
published references (Leathern, pers. com.). To my
knowledge the results of a discrete test of
whether Anachis avara is carnivorous or om-
nivorous have not been published. I conclude that
Anarchis avara can obtain nutriment from other
than carrion, particularly by grazing epibiota off
turtle grass blades, but also from particulate
organics in the sediment and from the water col-
umn. Where there is a plentiful source of food, I
doubt that food is a limiting resource for this
species in the seagrass flats near Miami, Florida.

ACKNOWLEDGMENTS

This work was completed as part of a disserta-
tion in partial fulfillment of the requirements for
the degree of Doctor of Philosophy at the Univer-
sity of Miami, Miami, Florida. I would like to
acknowledge the help of members of my commit-
tee of which Drs. H. B. Moore and D. R. Moore
critically read the manuscript.

LITERATURE CITED

Abbott. R. T. 1974. American Seashelk. Van Nostrand

Reinhold Co., New York. 66,3 pp.
Bandel, K. 1974. Spawning and development of some Col-

umbellidae from the Caribbean Sea of Colombia (South

America). The Fe/iser 16(3):271-282.

Spetimen Shells

Offering microscopic and miniature (to ' : inch) shells from
the Florida Keys, with accurate locality data. Also unsorted
grunge; write for list.

Margaret Teskey

P. 0. Bnx 27S

BiijPineKeii.FI -imi

Fretter. V. and A. Graham. 1%2. Rritijih Pmxohranch

A/(i//H,sr.s-; Their Functimml Anatomy and Eriiliigy. Ray

S(x.'iety. London. 7.5.5 pp.
Hiunm, H. J. 1964. Epiph>-tes of the sea grass. Vialaxsia

trxtiidinum in Florida. Btdt. Mar. Sri. Gulf and (hrih.

14(2):3()6-:i41.
Leathern. W. and D. Maurer. U)7.5. The distribution and

ecology of common marine and estuarine gastropods in the

Delaware Bay area. Nautihi.'^ 89(3):73-79.
Mareas, E. and E. Marcus. 1962. Studies on Columbellidae.

Bol. Far. Filo.'t. Cien. Let. Univ. San Pmdo. 261(Zool

21):a3.5-:»4.
Meyers. S. P., P. A. Orpurt. J. Simms and L. L. Boral. 19&5.

Thalassiomycetes VIL Observations on fungal infestation of

turtle gi-ass, Thalassia testudinum Konig. Bull. Mar. Sri.

15(3):.548-564.
Miller, A. C. 1974 A comparison of gastropod species diversity

and trophic structure in the rocky intertidal zone of the

temperate and tropical west Americas. Ph.D. Diss.. Univ. of

Oregon. 143 pp.
Moore, D. R. 1961. The marine and brackish water Mollusca of

the state of Mississippi. G«i/i?e.'i. Rep. l(l):l-58.
Puffer, E. L. and W. K. Emerson. 195,3. The moUuscan com-
munity of the oyster-reef biotope on the central Texas

coast. Jw/r. nfPaeleo. 27(4):537-.544.
Radwin, G. E. 1977. The family Columbellidae in the western

Atlantic. Part Ila: The Pyreninae. The VWi:g.'r20(2):119-133.
Raeihle, D. 1969. Egg cases of Nitidella ocellata Gmelin and

an Anachix. Ann. Report Amer. Malaeol. t'mon. :25-26.
Scheltema, A. H. 1968. Redescriptions of Anachis avara (Say)

and Anachis translirata (Ravenel) with notes on some

related species (Prosobranchia. Columbellidae). Breinora

304:1-18.
. 1969. Pelagic larvae of New England gastropods.

IV. Anachis translirata and Anachis avara (Columbellidae,
Prosobranchia). Vie et Milieu. Serie A: Biologie Marine

20(1-A):94-104.
Sokal. R. R. and F. J. Rohlf. 1969. Biometry W. H. Freeman

and Co., San Francisco. 776 pp.
Spight. T. M. 1976. Censuses of rocky shore prosobranchs from
Washington and Costa Rica. The Veliger 18(3):309-317.

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44 THE NAUTILUS

January 10, 1979

Vol. 93 (1)

FIELD EVIDENCE THAT THE EASTERN MUD SNAIL,

ILYANASSA OBSOLETA,
INFLUENCES NEMATODE COMMUNITY STRUCTURE'

Jean Ann Nichols and J. Roy Robertson

University of Ge^irgia

Marine Institute

Sapelo Island, GA 31327

ARSTRACT

Exclusion experiment's conducted with the mud snail, Ilyanassa obsoleta (Say), in
nematode and benthic diatom communities showed that the areas devoid of snails had
higher densities of both benthic diatoms and Pseiidotheristid nematodes than the con-
tiguous control area. We suggest that the increase in the diatmn-eating
Pseudotheristus s-p. in the exclusion plot was a behavioral response to increased
diatom densities, thus demonstrating an indirect trophic interaction between a
moUuscan macrofaunal herbivore and a nematode member of the meiofaunal com-
munity.

The mud snail Uynassa obsoleta (Say) is an
ubiquitous organism in the intertidal region,
ranging from the Gulf of St. Lawrence to north-
eastern Florida on the east coast of North
America. It is an omnivorous depositfeeder, ap-
parently subsisting almost entirely on ingested
sand and mud and associated organisms (Brown,
1969). The animal has been the subject of many
experimental and descriptive studies, but little
work has been concerned with the influence of /.
obsoleta on biological components of its environ-
ment. As a portion of a project to develop field
methods for analysis of possible trophic links be-
tween faunal groups, we initiated a series of ex-
periments on an intertidal salt marsh creekbank
at Sapelo Island, Georgia. Results from these ex-
periments indicate that when the eastern mud
snail Hyanai^sa obsoleta (Say) is excluded from an
area, meiofaunal nematode populations respond
to increases in diatom population and that this
response is most probably a result of feeding
behavior.

Wetzel (1976) demonstrated that Ilyanassa ob-
soleta (Say) can ingest and assimilate benthic
diatoms. In addition. Pace (1977) has shown that
if /. obsoleta (Say) is excluded from an area of

' Contribution No. 379 from the University of Georgia Marine
Institute.

the intertidal creekbank in the salt marsh, both
chlorophyll a and ATP concentrations in the top
centimeter of sediment show significant increases
within twenty-four hours. After five days the
concentrations of these substances increased
significantly within the 2-5 cm layer of sediment.
However, he did not determine the actual cause
of these increases. Since up to 90% of total sedi-
ment ATP can be attributed to nematodes
(Sikora et al.. 1977), it is possible that the dif-
ference in ATP concentrations observed by Pace
(1977) reflected significant changes in the
nematode community. We utilized similar e.xclu-
sion techniques to obtain diatom blooms with the
intent of studying numbers of individuals rather
than lumped sums of chlorophyll a and ATP.

The study area was the same as used by Pace
(1977). The intertidal sediment is 80% silt-clay. In
July, the time of this e.xperiment, the average
density of /. obsoleta (Say) is 1500 m ^ A one
meter square area was enclosed with ' 4" (0.635
cm) hardware cloth 50 cm high and extending 3
cm into the sediment. Snails were removed from
the enclosed area. One square meter contiguous
with the experimental area was used as a control.
Just after the water receded from the area, 3 cm'
pieces of lens paper (double thickness) were
placed in four randomly selected areas in both

Vol. 93 (1)

January 10, 1979

THE NAUTILUS 45

the experimental and control areas. Small cages
were placed around the lens paper in the control
area to prevent disturbance by snails during col-
lection of the algae. These cages were in place on-
ly during collection of algae. After three hours
the lens paper was collected and diatoms removed
by a method similar to that of Eaton and Moss
(1966). Briefly, lens papers were heated with
sulfuric acid and potassium permanganate. They
were then washed in distilled HjO by centrifug-
ing and decanting, transferred to vials and
brought to constant volume of 3 ml. Four sub-
samples (2 X 10" ml) from each vial were
counted using a hemacytometer. This method
may overestimate numbers due to cell breakage
and separation of valves (Eaton and Moss, 1966)
but is necessary to determine the species com-
position of the samples.

A ten cc syringe was used to collect samples of
the nematode population. It was assumed that
nematodes near the surface of the sediment were
more likely to be influenced by the diatom
populations than those in deeper sediments.
Therefore, only the top two centimeters of sedi-
ment were collected. Three samples, collected ran-
domly from both the experimental and control
areas, were fixed with formaldehyde (3% V/V).
After twenty-four hours in the formaldehyde
solution, samples were rinsed through a 45 j/m
mesh screen. Individuals retained on the screen
were counted. After dehydration, glycerine slide
mounts were prepared.

Data presented here are from samples obtained
on day 1 and day 5 of the experiment. On both
days the mean number of cells/ cm^ within the ex-
perimental area was greater than the control
area (Table 1). ANOVA tests of mean number of
diatom cells/ cm' indicate that there were signifi-
cant differences between the experimental and
control areas and between days. The significant
interaction term is due to the fact that the in-
crease in cell concentration from day 1 to day 5
was greater in the experimental area than in the
control area (Table 2.).

The patchy distribution of nematodes prevents
any meaningful statistical analysis of the
numbers of organisms obtained in the samples.
However, on day 1 the average number of
nematodes in all samples was 100. After five days

TABLE 1. Numbers of diatoms observed.

Day 1
Dav 5

Erperimpitt(d Cimtrol
2.93 0.67

7.12 1.27

Mean number of cells/an' X 10'

the average number of individuals in the control
area remained at 100. Average number of in-
dividuals within the experimental area had in-
creased to 300.

The change in species composition between day
1 and day 5 is of great interest. Initially, the
nematode populations were composed of about fif-
teen different families (several undescribed
species are represented), principally representing
the Enoplida and Monhysterida orders. This
diverse distribution remained in the control area.
On day 5, 70% of the individuals from the ex-
perimental area were Pseudotheristus sp. This
species represented only 19% of the population in
the control area. The actual number of non-
Pseudotheristus individuals remained stable in
both the experimental and control. Thus, the in-
crease in numbers of individuals in the ex-
perimental area was due entirely to the presence
of Pseudotheristus sp.

Information on the generation time of free-
living marine nematodes is scarce. Tietjen (1969)
and Tietjen and Lee (1972, 1973) have reported
minimum generation times of 22 days under op-
timal laboratory conditions. Hopper, Fell and
Cefalu (1973) report generation times of 1-^4 days
to 112 days for six free-living nematode species
cultured from decaying mangrove {Rhizophora
mangle) leaves. Since the first egg cleavage re-
quires from six to thirty-five hours (Hope, 1974),
it seems unlikely that reproduction could account
for the increase in numbers of adult individuals
observed during the period of five days.

TABLE 2. Analysis of variance of diatom numbers.

.SN df

)hs F

p

Treatment

406.4.5 .3

cage

26:3.12 1

263.12 47.92

<.001

days

91.93 1

91.93 16.65

<.005

interaction

.51.41 1

51.41 9.38

<.001

Samples

65.92 12

5.49

SS = sum of squares; df = degree of freedom; ms = mean
square.

46 THE NAUTILUS

January 10, 1979

Vol. 93(1)

S^eventy-five percent of the Pfteudotheri.'^tus sp.
contained diatoms within their guts. Individuals
contained from two to twenty-two diatom
frustules. In most cases chioroplasts were visible
when the frustule was located in the anterior
portion of the gut. but not in the posterior posi-
tion. Diatoms were not found in the guts of any
of the other species of nematodes in either the
control or experimental area.

While it is possible that the difference in
nematode density was because predation by the
mud snails, two lines of evidence render this in-
terpretation unlikely: dissection of over thirty /.
obsioleta (Say) revealed no nematodes in their
caecae and the change in nematode density was
entirely due to increase in the Pseudothe7i.<itvs
sp. population. It is unlikely that /. ohsoleta (Say)
individuals exercise any selection over the type of
material ingested from the substrate (Brown,
1969). Therefore, we suggest that the increase in
Pseudotheristus sp. is a result of competitive
release, thus demonstrating an indirect trophic
interaction between the macrofaunal species R-
yanassa ohsoleta (Say) and the meiofaunal species
PsevAotheristns sp.

LITERATURE CITED

Brown, S. C. 1969. The structure and function of the digestive

system of the mud snail Nassarius obsoletus (Say).

Malacologia 9:447-498.
Eaton, J. W., Moss, B. 1966. The estimation of numbers and

pigment content in epipelagic algal populations. Limnol.

Oceaniiyr. 11:584-. ^.5.
Hope, W. D. 1974. Nematoda. In Reproduction of Marine In-

vetiehrntes Vol. 1. (Giese. A. C. & Pearse, .1. S.. ed.)

Academic Press. New York. pp. 391-470.
Hopper, B. E.. Fell, J. W., and C«falu, R. C. 1973. Effect of

temperature on life cycles of nematodes associated with the

Mangrove (Rhizophnra mangle) Detrital System. Marine

Bn(/(v.'/ 23:293-296.
Pace. M. L. 1977. The effect of macroconsumer grazing on the

benthic microbial community of a salt marsh mudflat. MJ^.

Tliesis. University of Georgia. Athens, Georgia. 80 pp.
Sikora, J. P., Sikora, W. B.. Erkenbrecher. C. W., and Coull,

B. C. 1977. Significance of ATP. carbon, and caloric content

of meiobenthic nematodes in partitioning benthic biomass.

Marine Binlogy 44:7-14.
Tietjen. .1. H. 1969. The ecology of shallow water meiofauna in

two New England estuaries. Ckcohiyia 2:2.51-291.
Tietjen, J. H., Lee. J. J. 1972. Life cycles of marine nematodes.

Oecoloyid 10:167-176.
. 1973. Life history and feeding habits of the

marine nematode, Chromaiiora macrolaimoidex Steiner.

Oecologia 12:303-314.
Wetzel. R. L. 1976. Carbon resources of a benthic salt marsh

invertebrate, Nassarius obsoletus Say (Mollusca:

Na.s.sariidae). In Estuarine Processes. Vol. 11 (Wiley, M.,

ed.) Academic Press. New York. pp. 293-.308.

LIVING MARINE

MOLLUSCS

ECOLOGY

REPRODUCTION

ANATOMY

C, M. Yonge and T. E. Thompson

An Understandable Biology Text

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"—/?. Tucker
Abbott. Ph.D.

Clothbound, 288 pp., 162 text figures, 16 plates
with 18 glorious color photographs $14.9.S

american malacologists

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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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Several museums of natural history have ex-
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APRIL 23, 1979

(April and July numbers combined)

THE

NAUTILUS

ISSN 0028-1344
Vol. 93

No9. 2 and 3

A quarterly

devoted to

malacology and

the interests of

conchologists

Founded 1889 bv Henry A. Pilsbr>'. Continued by H. Burrington Baker.
Editor-in-Chief: R. Tucker Abbott

EDITORIAL COMMITTEE

CONSULTING EDITORS

Dr. Arthur H. Qarke, Jr.

Division of Mollusks

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
Woods Hole Biological Laboratory
National Marine Fisheries Sei-vice
Woods Hole, Massachusetts 02543

Dr. Donald R. Moore
Division of Marine Geolog>'
School of Marine and Atmospheric Science
10 Rickenbacker Causeway
Miami, Florida 33149

Dr. Joseph Rosewater
Division of Mollusks
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

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THE

NAUTILUS

Volume 93, numbers 2-3 — April 23, 1979

ISSN 0028-1344

CONTENTS

Bernadine Barker Baker

A Tribute Upon her Retirement '^

Melbourne R. Carriker , , . ,o, . \n

Ultrastructural Effect of Cleaning MoUuscan Shell with Sodium Hypochlorite (Clorox) 4/

David R. Lindberg

Variations in the Limpet. CoUiseUa ochracea,

and the Distribution oiNatoacmea testudinalis (Acmaeidae) ^

HansBertsch t, /i^ ^ r> c \ k^

Tropical Faunal AffinitiesofOpisthobranchsft-om the PanamicProvmce (Eastern Pacific) i>i

Melissa A. Barbour

A Note on the Distribution and Food Preference of Cadlina laems

(Nudibranchia: Chromodoridae)

Dorothea S. Franzen tt • jo <. kq

Catinella paralleled A New Succinidae (Pulmonata) from Midwestern United States ^^

Billy G. Isom, Sally D. Dennis and Charles Gooch

Rediscovery of Some Pleurocerids (Gastropoda) Near Muscle Shoals,

Tennessee River, Alabama

Amy Shrader Van Devender

A New Vertkjii (Pulmonata: Pupillidae) from the Ozarkian Uplift

Alton C. Boozer and P. E. Mirkes

Observations on the Fingernail C\&mjiusculium partumeivm (Pisidiidae),

and its Association with the Introduced Asiatic Clam, Corbiculafluminea '-i

Billy G. Isom, Charles Gooch and Sally D. Dennis

Rediscovery of a Presumed Extinct River Mussel, Dijf^nnmia sulcata (Unionidae) »4

Terrence M. Gosliner , j j ^ qr

A Review of the Systematics of CylichneUa Gabb (Opisthobranchia: Scaphandridae) "•'^

Robert S. Prezant „„

Shell Spinules of the Bivalve, L?/onsia hyalina ^^

William J. Clench

A Biography of Andrew Garrett, Early Naturalist of Polynesia: Part 2:

Catalogue of Molluscan Species and Bibliography

Hugh J. Michael-Tapping , , , ino

The Caecidae (Gastropoda: Rissoacea) of Water Island, U.S. Virgin Islands, with a new species W6

Donald R. Moore and Mabel Fentress Miller

Discovery of Living Bivalved Gastropods in the Florida Keys i""

News

56, 92 Recent Death (Teramachi) 83

BERNADINE BARKER BAKER
Retiring Business Manager of The Nautilus

For nearly half a century Mrs. H. Burrington
Baker, known to her friends as Bunny, has either
collected shells, written about shells, or has been
actively assisting scientists and editors in their
malacological endeavors. S(K)n after she married
the zoologist, and co-editor of The Nautilus, H.
B. Baker in 1941, Bunny began proofing manu-
scripts and keeping the subscription records.
Throughout the following 38 yeai-s her voluntary
assistance has made the continuation of Tlic
NaiitUii.<; possible.

Mrs. Baker has been the fourth Business and
Subscription Manager in the 93-year life of this
journal. The first was its co-founder, William D.
Averell (1853-1928) of Mt. Airy, Philadelphia,
who served for the first three volumes from 1886
to 1890. The second was Charles W. Johnson
(1863-1932) of Philadelphia and later of Boston
who served from 1890 until his death in 1932 over
a period of 42 volumes. The third was Horace
Burrington Baker (1889-1971), of Havertowm, Pa.,
who served from 1932 to 1958 when he then be-
came senior editor. It was at this time during the
71st volume that Bunny became the fourth Busi-

ness Manager and has served in that capacity for
20 years. Although retiring now, and still very
active in the affairs of the Delaware County
Memorial Hospital, Bunny is in excellent health
and will continue to give sage advice and guid-
ance to The Nautilus.

Bernadine Barker Baker was bom October 1,
1906, in Quincy, Massachusetts, and received her
A. B. degree in 1928 from Radcliffe College in
Cambridge, Mass. She taught at Burdett College
for three years, then was Financial Secretar>' at
the Children's Museum in Boston where she first
became interested in shells. With her co-worker
Mildred Seymour (later MacCoy), Bunny ventur-
ed on an expedition with Harvard scientists in
1934 to the Everglades of Florida.

Mi-s. Baker is a Life Member of the American
Malacological Union, having joined as early as
1934, and served as its Treasurer from 1966 to
1972. She was Secretary of the Boston Mala-
cological Club from 1935 to 1941, and is a charter
member of both the Philadelphia and Wilmington
Shell Clubs. Her interests have been mainly in
marine mollusks. Her collection was donated to
the Museum of Comparative Zoology, at Harvard,
a few years ago. She published two scientific ar-
ticles in The Nautilus, one in 1950 on the marine
mollusks of St. Petersburg, and the other in 1951
on "Interesting Shells from the Delmarva Penin-
sula."

Bunny was engaged to her future husband at
the 1941 A. M. U. meetings in Rockland. Maine,
and appropriately they spent their hone.vmoon on
shell-rich Sanibel Island, Florida. Until "H. B.'s"
death in 1971, she assisted in 77!* Nautilus mat-
ters, and raised two daughters, Elizabeth, now
Mrs. Warren Brandkamp, and Abigail, now Mrs.
John Kraljevich. She has four grandchildren. Her
husband immortalized her name in malacological
literature in 1942 by naming a new genus and
new species of Mexican land snail, Bunnya ber-
nadinae. For 17 years Bunny has been a vol-
unteer worker at the Delaware County Memorial
Hospital (see Our Family, vol. 5, no. 10, Aug.
1977), and she continues to assist in their Gift
Shop. Among her hobbies are hooking rugs and
collecting miniature bunnies. Bunny may still be
reached by her friends at 11 Chelten Road,
Havertown, PA, 19083. (R. T. Abbott).

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 47

ULTRASTRUCTURAL EFFECT OF CLEANING MOLLUSCAN SHELL
WITH SODIUM HYPOCHLORITE (CLOROX)

Melbourne R. Carriker

College of Marine Studies
University of Delaware
Lewes, Delaware 19958

ABSTRACT

The corrosive effect of sodium hypochlorite (commercial clorox) on the ultra-
structure of the (i)yanir components of the shell of the bivalve Mytilus edulis
Linne is described, and the detrimental results are related to cleaning of mollus-
can shells preparatory to storage in collections.

INTRODUCTION

Sodium hypochlorite solutions have been em-
ployed routinely by shell collectors for some time
to remove algal and other organic grovrths from
the exterior of molluscan shells in preparation
for storing them in collections (Abbott, 1954;
Bales, 1974).

Commercial clorox, 5.25% sodium hypochlorite,
available at most grocery stores, does not
disfigure the mineral portions of shells, but does
dissolve the organic matter. Soft molluscan and
other tissues are dissolved rapidly (in a few
seconds), while tough tissues, like molluscan
periostracum and ligament, take considerably
longer. Hamilton (1969), for example, was forced
to treat valves of tellinid bivalves for as long as
30 to 60 days to completely remove the perios-
tracum. Differential dissolution of organic matrix
of shell by sodium hypochlorite has been used to
good advantage by such investigators as Towe
and Hamilton (1968), Mutvei (1970), and Carriker
(1978) in the study of the fine structure of the
units of molluscan shell.

The purpose of this note is to describe the ef-
fect of clorox on molluscan shell at ultrastruc-
tural magnifications, and to discuss these obser-
vations with reference to the procedures em-
ployed by shell collectors in cleaning shells.

METHODS

Shells of the bivalve Mytilus edulis Linne were
employed for testing the effect of solutions of
sodium hypochlorite. Rapidly growing specimens,
approximately 6 cm in length, were collected in

the vicinity of Woods Hole, Massachusetts.
Valves, freshly cleaned of meats and washed in
tap water, were shattered with a blow from a
hammer. Pieces of shell, about 4 to 8 mm in long-
est dimension, were selected from the thick mid-
dle region of the valves. All major layers of shell
were represented in each fragment: the exterior
organic periostracum, the calcific prismatic
stratum, and the aragonitic nacreous layer next
to the mantle (see Carriker, 1978, for review of
the ultrastructure of the shell of this bivalve).

Several pieces of shell were placed in each of
three small beakers, each beaker containing 30 ml
of full strength commercial clorox (5.25% sodium
hypochlorite). Beakers were covered, gently swirled
by hand from time to time, and maintained
at room temperature in a laboratory normal-
ly lighted with overhead fluorescent illumina-
tion. Shell pieces in beaker a) were immersed in
clorox for 10 minutes, those in beaker b) for 30
minutes, and those in beaker c) for 40 hours. At
the end of these periods, shell fragments were
rinsed several times in cold tap water, drained on
absorbent paper, and dried in a stream of warm
air. Representative pieces from the three beakers
were then mounted on 1 cm brass stubs with
silver paint, dried in an oven at 60°C for a day,
coated with gold in vacuum, and examined with a
scanning electron microscope, using magnifica-
tions of 2000 to 6000 times at a voltage of 15 k\'.

RESULTS

Ridges on the untreated surface of the perios-
tracum of Mytilus edulis ranged in width from

48 THE NAUTILUS

April Z% 1979

Vol. 93 (2-3)

1.4 to 2 fiin (Fig. 1). This corrugated pattern was
completely destroyed by treatment with clorox
for 40 hours (Fig. 2), leaving cracked, buckled
shreds of periostracum draping over the tops of
tubercles of the thin mo-saicostracal layer (Car-
riker, 1979) which binds the periostracum to the
prismatic layer of the shell. Immersion of perios-
tracum in clorox for shorter periods resulted in
progressively less erosion of its surface.

Treatment of fractured surfaces of the
prismatic layer of shell with clorox for 40 hours
(Fig. 5) caused complete removal of the inter-
pristmatic organic matrix (conchiolin) which sur-
rounds each individual prism as an envelope and
binds adjacent prisms to each other (compare
with Fig. 3; prisms roughly 1 to 3 fim in major
cross sectional dimension). The treatment also

FIG. 1. Exterior of periostracum i/Mytilus edulis near edge
of valve illustrating ntrrmal, smonthly corrugated, untreated
surface. Scanning electron micrograph. Scale bar = 2 \im.
2, Exterior of periostracum after treatment with clorox for JfO
hours. Periostracum was partially dvisolved. and as it dried,
cracked atul warped. Scanning electron micrograph. Scale bar
— S fim. 3, Normal untreated fractured surface of prismatic
layer of shell showing broken erids and .'ddes of indicidual.
closely fitting, anvil-shaped prisms. Scanning electron
micrograph. Scale bar = 2 yan. 4, Fractured surface of
prismatic layer of shell treated with clorox for 10 minutes.
Most of interprismatic organic envelope uvs removed from
each pri.'sm exposing pattern of mineral crystals beneath.
Scanning electron micrograph. Scale bar = 2ym.

etched some of the intraprismatic organic matrix
from the mineral crj'stals within the prisms,
revealing the jagged edges of what appeared like
mineral platelets. Treatment with clorox for 10
minutes (Fig. 4) resulted in the removal of only
part of the interprismatic organic matrix.

Exposure of the mantle surface of the nacre to
clorox for 40 hours resulted in dissolution of the
organic matrix which surrounds individual
lamellae and cements them to each other (Fig. 7,
compare with Fig. 6; lamellae roughly 5 to 10 (jm
in longest dimension). Removal of the matrix
created a pattern of polygonal figures illustrated
in the several terraces of lamellae exposed in
Figure 7. A threefold enlargement of Figure 7
(Fig. 8) showed further that the clorox also
solubilized some of the intracrystalline organic
matrix within the lamellae, exposing what ap-
peared like internal lath shaped substructures.

DISCUSSION

As other workers have discovered (Carriker,
197S. Hamilton. 1969; Mutvei, 1970; Towe and
Hamilton. 1968). clorox is a highly efficient
solubilizer of molluscan organic materials. Ex-
cessive use of full strength clorox in the cleaning
of shells, however, can alter the ultrastructural
nature of the shell surface, whereas when em-
ployed with discretion, the chemical is extremely
useful in cleaning periostracal and ligamental
surfaces of molluscan shells. Unpublished obser-
vations and the published work of others (Abbott,
1964: Bales, 1974) demonstrated that it is dif-
ficult to prescribe a given concentration or time
for the use of clorox in cleaning the exterior
surface of a particular species of shell. The age of
the shell and previous exposure of the surface to
weathering and to microbiological action are fac-
tors which increase the vulnerability of the sur-
face to dissolution. Each specimen must thus be
treated individually, and application of the
chemical must be made initially for a brief
period of time. For fragile specimens it is impor-
tant to use clorox diluted five to twenty or more
times with tap water. S. E. Siddall and R. A.
Lutz (personal communication), for example, em-
ploy 2% alkalized (pH 9) clorox to dissolve the
ligament of mussel larvae when examining the

Vol. 93 (2-3)

Api'il 23. 1979

THE NAUTILUS 49

FIG. 5. Fractured surface of prismatic layer of shell treated
with clorox for iO hours. Interprismatic and some of in-
traprismatic organic matrix was solvbilized, leaving con-
spiawus spaces among prism ends. Scanniitg electron
micrograph. Scale bar = 2 yim. 6, Normal, untreated, oblique,
fractured surface of nacreous layer of shell showing teiraces
of brick-shaped lamellae. Scanning electron micrograph. Scale
bar = 2 fim. 7, Surface of nacreous layer of shell facing man-
tle treated uith clorox for iO hours. Organic matrix between
adjacent lamellae was dissolved resulting in pattern of
polygonal figures. Scanning electron micrograph. Scale bar =
6 \m. 8, Same surface as in Fig. 7 magnified three times
more. Dissolution of superficial organic matrix within
lamellae revealed substructure of lamellae. Scanning electron
micrograph. Scale bar = iftm.

hinge structure. After initial immersion in
clorox, careful rinsing in tap water, and drying,
the surface of the specimen should be examined
for effectiveness of removal of organic growths
and for possible loss of sheen and color resulting
from chemical deterioration of the surface.
Guided by frequent visual examinations (prefer-
ably under a binocular microscope especially for
small fragile specimens), the shell preparator can
generally safely employ the required number of
immersions in clorox to remove extraneous or-
ganic materials without objectionably altering
the surface of the periostracum and ligament.

The organic matrix of the nacreous inner sur-
face of valves, however, is much more vulnerable
to dissolution by clorox than periostracum and

ligament (see Fig. 7, 8). With the exception of
fragments of flesh clinging to the muscle scars
(myostracum), the nacreous surface is usually
clean in freshly opened molluscs. It is thus
necessary only to dissolve the organic matter on
myostracal areas. This can be done without
harming the nacre to any extent by carefully
"applying" clorox only over the myostracal sur-
faces under a binocular microscope, observing the
same precautions given in the previous paragraph
for periostracal and ligamental surfaces.

Malacologists and conchologists often soak
freshly collected shells in tap or seawater for a
time to allow removal pf muscle tissue from the
myostraca by autolysis and bacterial decomposi-
tion. This treatment is effective in removing
tissues, but caution must be observed as the
treatment may also disfigure the nacreous sur-
face as a result of the accumulation of acids in
the water. K water must be used, it is safer to
employ seawater because it possesses a con-
siderably greater buffering capacity than does
freshwater.

The observations reported in this paper suggest
that caution should be exercised against over ex-
posure to clorox in cleaning shells especially for
permanent storage in study collections.

ACKNOWLEDGMENTS

Thanks are extended to Virginia Peters for col-
laboration in the scanning electron microscopy, to
W'alter S. Kay for preparing the final prints for
publication and to R. Tucker Abbott for helpful
comments on the manuscript. University of
Delaware, College of Marine Studies Contribution
Number 123.

LITERATURE CITED

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

Inc.. Princeton. N. J. .541 pp.
Bales, B. R. 1974. Cleaning marine shells, in M. K. Jacobson.

Ed., How to study and collect shells. Amer. Malacological

Union, pp. 12-16.
Carriker. M. R. 1977. Ultrastructural evidence that gastropods

swallow shell rasped during hole boring. Biological Bulletin

152: 325-336.
. 1978. Ultrastructural analysis of dissolution of

shell of the bivalve Mytilus edulis by the accessory boring

organ of the gastropod Urosalpinx cinera. Marine Biology

48: 105-134.

50 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

1979. L'ltrastructure of the mosaicostracal layer of

the shell of the bivalve Mylilus edulis. (Submitted to The
Veliyer). In pres.s. vol. 21. no. 4.

Hamilton, G. H. 1969. The taxonomic significance and
theoretical origin of surface patterns on a newly discovered
bivalve shell layer, the mosaicostracum. The Veliger 11:
185-194.

Mutvei, H. 1970. Ultrastructure of the mineral and organic
components of molluscan nacreous layers. BiominTulizatum
Res. Rept. 2: 48-74.

Tnwe, K. M.. G. H. Hamilton. 1968. Ultrastructure and infer-
red calcification of the mature and developing nacre in
bivalve mollusks.C<i/r. Tiss. Res. 1: 306-318.

VARIATIONS IN THE LIMPET, COLUSELLA OCHRACEA AND THE

NORTHEASTERN PACIFIC
DISTRIBUTION OF NOTOACMEA TESTUDINALIS (ACMAEIDAE)

David R. Lindberg

Department of Invertebrate Zoology

California Academy of Sciences

San Francisco, California 94118 U.S.A.

In August, 1975, I collected a series of small
limpets, less than 10 mm in length, from the
shells of the abalone, Haliotis mfeacens Swainson,
1822, at a depth of 8 m off Kruse Ranch, Men-
docino County, California (38°35'N). My initial ef-
forts to identify the specimens using shell
characters failed, so I examined radulae from
several of the specimens. Radulae from other
small limpets which had been obtained from
shells of Tegula pulligo (Gmelin, 1791), collected
in Monterey Bay, California (36°36'N), had
previously been prepared. When compared to
those of the Kruse Ranch specimens, the radulae
proved to be very similar, although the shells of
the two groups of specimens differed markedly in
coloration and morphology-.

As additional material was examined, rudular
characters initially thought to be unique to these
two sets of specimens were also found to be pre-
sent in CoUviella ochracea (Ball, 1871). I now
consider the limpets from H. nifescens and T.
pulligo to be previously unreported forms of C.
ochracea.

Subsequent to this, I encountered problems in
attempting to establish the most northern dis-
tributional record for C ochracea. Specimens
identified as C. ochracea from western Alaska

were not similar to southern specimens. After ex-
tensive examination and comparisons, these spec-
imens were recognized as Notdacmeo testudinalis
(Muller, 1776), the presence of which in the east-
ern Pacific has been the subject of controversy.

This paper discusses and figures the various
forms of C. ochracea and contains notes on the
natural history of this species. Also included is a
review of the presence of N. testudinalis in the
eastern Pacific, with a discussion of its similari-
ties to, and differences from, C. ochracea.

Abbreviations used in the text :

CAS - California Academy of Sciences, San

Francisco, California.

CASG - Department of Geology, Cal. Acad.

Sciences.

CASIZ - Department of Invertebrate Zoology,

Cal. Acad. Sciences.

LACM - Los Angeles County Museum of

Natural History, Los Angeles, California, De-
partment of Malacology.

Collisella ochracea

Collisella ochracea is a little-known eastern
Pacific species. Dall (1871: 249) described it from
Monterey, California, as a variety of Acmaea
patina Rathke, 1833 [now Notoacmea scutum
(Riithke, 1833)], and it was treated as such by

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 51

Dall (1879: 1914; 1921), Pilsbry (1891), and
Oldroyd (1927). A. R. Grant (1933) was the first
worker to recognize C. ochracea as a distinct
species and in a later thesis (Grant, 1938) correct-
ly placed Acmaea peramabilis Dall, 1872, in
synonymy. Observations by Grant (1938) of the
radula of C. (xhracea further demonstrated its
distinctness. The radular strap was found to bear
vestigial, marginal teeth (uncini), the presence of
which assigned C. ochracea to the genus Callisella
rather than to Notoacmea. the genus to which A'.
scutum belongs. Grant's treatment of C. ochracea
was followed by the majority of subsequent
workers, including Keen (1937), Burch (1946),
Smith and Gordon (1948), Light, et al. (1955),
Fritchman (1961), McLean (1966, 1969). and
Carlton and Roth (1975). However, as recently as
1974, C. ochracea has again been erroneously
listed as a variety of A^. scutum (Abbott, 1974:
32).

In 1945 and 1946 Avery Ransome (Grant) Test
published parts of her 1933 and 1938 theses. In
the first paper the ecology of C. ochracea was
discussed in a single paragraph in which she
stated that the limpet occurs in the lower inter-
tidal zone on rocks that are largely bare of
macroscopic algae, appearing to be limited to this
habitat by food (microscopic algae), the lack of
competition, and permanent submergence. In the
later paper (Test, 1946), C. ochracea was reported
to be related to Collisella pelta (Rathke, 1833)
based on a study of the radular characters. My
own observations do not support this relationship
nor is another evident at this time. Yonge (1962)
included the species in his study of mantle cavity
currents in acmaeids. McLean (1969: 17) reported
that C. ochracea is one of the few acmaeid species
occurring subtidally. McLean (loc. cit.) was also
the first worker to refer to C. ochracea as being a
common species. The range of C. ochracea is Cap-
tain's Bay, Unalaska Island. Alaska (53°03'N) to
Isla Cedros. Baja California, Mexico (28°12'N).

The Forms of Collisella ochracea
Collisella ochracea is an eurytopic, polyt>-pic
species. It occurs on several different substrata
and has shell color patterns and morphology that

vary with the substratum occupied. One form oc-
curs on the shells of trochid gastropods. A second
variation occurs on encrusting coralline algae and
two other forms occur in the low int«rtidal and
subtidal zones. Only these last two were recog-
nized and described by Grant (1933: 111).

Although each form is described separately be-
low, several general characters are present on all
specimens. The sculpture of C. ochracea consists
of fine, non-bifurcating riblets. The riblets are
consistently straight and evenly spaced. The aper-
ture of C. ochracea may vary from circular (Fig.
2) to elongate (Fig. 4).

Solid and Tessellate Forms (Figs. 1-2)

Description: Shell of low to medium profile;
apex in anterior third of shell length. Anterior
and lateral slopes straight, posterior slope slight-
ly convex. Solid form pale yellow to rose red.
Tessellate form brown to gray, with symmetrical
white markings, pattern finer at apex than at
edge. White markings sometimes drawn out into
bars at edge. Internal margin darker than in-
termediate or apical areas, sometimes streaked
with white corresponding to external pattern. In-
termediate and apical areas may be suffused with
blue. Internal stain, when present in solid form,
not covering apical area.

Remarks: As previously stated these two forms
have been recognized since 1933 and they occur
on smooth, bare rocks and reefs in the low
intertidal and subtidal areas. McLean (1966:
77) stated that specimens are common to depths
of 9 m, but are seldom collected below this.

Coralline Form (Fig. 3)

Description: Shell of low to medium profile:
apex in anterior third of shell length. Anterior
slope concave; posterior slope convex; lateral
slopes straight. Aperture anteriorly narrowed.
External color pattern of brown to red coalescing
markings on a white background; pattern at apex
finer than at edge. Apex erodes to white. Internal
margin white, with markings corresponding to
pattern at external edge; internal stain, when
present, not extending into apical area. Shell
translucent.

52 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

Remarks: This form occurs on intertidal and
subtidal substrata encrusted with coralline algae
of the genus Lithothamnion. including rocks,
boulders, and the shells of H. rufescens. The con-
cave anterior slope of this form distinguishes it
from the other forms of this species. A form of
Collisella pelta is also found on such surfaces, but
it is readily distinguished from C. uchracea by its
lack of fine riblets.

Epizoic Form (Fig. 4)

Descriptidn: Shell of medium profile; apex in
anterior quarter of shell length. Anterior and
lateral slopes straight; posterior slope slightly
convex. Aperture elongate; lateral edges parallel.
External color tan to reddish brown, generally
mottled with white or with white markings. Solid
forms occur. Apex erodes to white. Internal
margin dark, with or without white markings
corresponding to the external pattern which is
visible through shell. Generally lacking internal
stain.

Remarks: This form occurs on the trochid
gastropods Tegula brunnea (Philippi, 1848),
Tegula montereyi (Kiener, 1850), and Tegula
pidligo (Gmelin, 1791). The majority of my
specimens have been collected from T. pulligo in
the Monterey Bay area. This form of C. ochracea
has been found on T. brunnea and T. montereyi
in San Mateo County, California, and a single
specimen of it was found at Bodega Bay, Marin
County, California, on T. brunnea. Trochid
gastropods are commonly utilized as substrata by
acmaeid limpets. Cnllisella asmi (Middendorff,
1847) was considered to be the only epizoic limpet

on Tegula funebralis (A. Adams, 1855). However,
McLean (1966: 80) reported that Collisella
strigatella (Carpenter, 1846) was also abundant
on T funebralis in the Monterey area, and
Brewer (1975) reported six additional species of
acmaeid limpets on T. funebralis. T. funebralis is
a mid-intertidal species, and the limpets which
occur on it are also found in the same intertidal
zone. All three species of Tegula on which C.
ochracea has been found are low intertidal and
offshore kelp bed species (Carlton and Roth, 1975:
502-503) which corresponds to the habitat of C.
ochracea.

Laminaria Form

After the manuscript was submitted to the edi-
tor a fifth form of Collisella ochracea was brought
to my attention by M. G. Kellogg, Moss Landing
Marine Laboratories, Moss Landing, CA. This ad-
ditional form occurs on the stipes of the brown
algae Laminaria dentigera and Pterygophora
califomica; both algae are typical habitats of Col-
lisella instabilis (Gould, 1846). Both C. instabilis
and the C. ochracea form have similar gross shell
morphologies (i.e. elevated anterior and posterior
shell margins), but differ in shell markings and
sculpture. The C. ochracea form is brown with
white markings similar to those of the tessellated
form described above. Collisella instabilis is also
brown but lacks the white markings although the
apical area typically erodes to white. The
sculpture of the C. ochracea form is as described
above, with straight, raised riblets. The sculpture
of C. in.'^tabilis consists of broadly-spaced grooves
giving the appearance of obscure, flat ribs.

Figures 1-10 (see opposite page)

All figure.^ actual xue unless otherwise noted.

FIGS. 1-10. 1-4. Collisella ochracea (Dull). 1, Tes-sellate form. California: San Mateo County: Pillar Point. CASIZ No.
0031,19. 2, Solid fiinn. California: Mendocino County: Little River, .5871? CASCi Type Collection: 3, Coralline form. California: San
Mateo County. Ano Nucvo Pirint. CASIZ No. 0OS:i96. X 2. 4, Epizoic form. California: Monterey C(mnty. San .Jme Creek Beach, on
Tegula pulligo (Gmelin). CASIZ No. 00.1:190. X 2 5-6. Raduia i;/' Collisella ochracea (Datl). California: Mendocino County: Kruse
Ranch, CASIZ No. 00;lil8, X 250. 5, Radular tooth ronfiyuration, FLT = fiist lateral tooth: SLT = .'<econd lateral tooth: TI.T =
third lateral tooth, U = uncinus. 6, Brts-a/ plalc ntoriiholoyy: FLP = first lateml plate: SLP = second lateral plate: TI.P — third
lateral plate: VP = ventral plate: AP = anterior pivcess: AS — anterior .future. 7. Collisella ochracea (Dall). California: Santa
Cruz Cmtnty: Soqnet Point, CASIZ No. 00:1:19:1. Note shell color pattern change at apex. Enlargement X 7. &. Notoacmea
testudinalis (M'dler). 8A, Ataxka: Prittilof Islandi. St. Paid Island. .58716 CAS(! Type Collection: 8B, Alaska: Kenai Peninsula:
Kachcmak Hay. Cohen Island. lACM No. 7.1-20. 9-10. Raduia u/Notoacmea testudinalis (M'dler). Alaska: Prihilof Island.^. St. Paul
Island. St. Paul Village. LACM No. 7:1-21,. X. 200. 9, Radular tooth configuration (see Fig. H for legend). 10, Basal plate niorphology
(see Fig. Hfor legend).

Vol. 93 (2-3)

April 23, 1979

thp: nautilus as

fn

c

V

I

2

<^>^.

B

10

For explanations, see opposite page (Lindberg on Acmaeidae).

54 thp: nautilus

April 23. 1979

Vol. 93 (2-3)

The Radula of Collisella ochracea

Although shell color varies significantly in this
species, radular characters appear consistent.

Grant (1938: pit. 30, Fig. 2) figured the radular
strap and basal plates of C. ochracea, but did not
discuss or figure tooth configuration or mor-
phologj'. She did mention the presence of elon-
gated uncini. McLean (1966: 77) described the
lateral teeth and basal plate morphologj', and
gave length/width ratios for the ribbon seg-
ments.

The radular tooth configuration of C. ochncea
(Fig. 5) is typical of members of the genus. The
first lateral teeth are close together on the an-
terior end of the segment and are rounded distal-
ly. The second laterals are posterior to the first
laterals and are sub-rectangular, with broad
straight cutting edges. The third laterals are obli-
que and are distal to the second laterals; they are
wedge-shaped and smaller than the other laterals.
The uncini are elongate and curve over the
posterior comers of the ventral plates. The tips
may be slightly broadened.

The basal plate morphology of the radula (Fig.
6) is also typical of members of the genus. The
first lateral plates are sub-rectangular; the second
lateral plates broad and posteriorly rounded; and
the third lateral plates are separated from the sec-
ond lateral plates by a strong partial suture.
The third lateral plate is biformed, the inner sec-
tion rounded distally and extends beyond the sec-
ond lateral plate edge. The outer section is
pointed distally and extends to the vicinity of the
uncini. The ventral plates are clearly defined and
bear both a strong anterior suture and pro-
cess-the anterior process is difficult to see in
radular mounts with closely spaced segments.

Natural History Notes

Specimens of C. ochracea of both sexes, some
with shell lengths of less than 5 mm, have been
found in a gravid state, and some of these from
central California are known to have been col-
lected in the months of February through
August.

The bathymetric range of C. ochracea extends
from the low intertidal (= 0.0 feet) to a little

over 40 m. No .submergence in the southern por-
tion of the distribution of this species appears to
occur, although Baja California specimens appear
limited to areas of cold-water upwellings.

C ochracea also occurs in the turbid water of
San Francisco Bay, California (37°48'N) on the
sides and bottoms of small rocks embedded in
sand and gravel sediments and on fouled pilings
in Monterey Harbor. The occurence of C. ochracea
in such habitats is not surprising in view of
Yonge's (1962) report that C. ochracea has a man-
tle current pattern similar to that of Notoacmea
test7idinali% a species often found associated with
sediment-laden water.

DISCUSSION

While the epizoic and coralline forms of C.
ochracea are directly referable to particular
substrata, the solid and tessellate forms appear to
occur homogeneously in the intertidal and sub-
tidal areas of central California. However, in a
survey of over 400 specimens some geographic
correlations of these forms were noted. Tesselate
forms predominate in the southern part of the
geographic distribution (south of 38°N) and
decrease to the north; the solid forms predomi-
nate in the north and appear to decrease to the
south (Table 1).

Some movement of individuals between sub-
strata may exist. These movements are suggested
by changes in shell morphology and shell color.
Solid forms have been examined with the fine
reticulate pattern of the coralline form visible at
the apex (Fig. 7). The presence of the fine
reticulate pattern may indicate movement from a
coralline substratum to the exposed rock reefs,
the typical habitat of solid forms. Changes in
shell morphology and color have also been noted
for C. pelta which may change substrata
(McLean, 1966: 59).

Notoacmea testudinalis (Muller)

Although well-known on the east coast of
North America (Abbott, 1974; Emerson and
Jacobson, 1976), Arctic Canada and Europe (Mac-
pherson, 1971), the presence of Notoacmea
testudinalis in the northeastern Pacific has been

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 55

TABLE 1. Getiymphiciil Distribution of Solid and Teaselate Firrms o/Collisella ochracea iDdlj in the Ka-steni Piwijic.

DEGREES NORTH LATITUDE

SOLID FORM
# of specimens % of specimens

TLSSELLATE FORM TOTAL « OF

# of specimens % of specimens SPECIMENS

<32

2

2

116

98

118

32-35

18

IB

80

82

98

36-37

54

38

88

62

142

38-40

22

63

13

37

35

41-43

0

—

1

100

1

44-46

0

—

0

—

0

47-49

0

—

0

—

0

>49

12

92

1

8

13

E

108

299

407

the subject of considerable debate. Dall (1871)
considered N. testudinalis to be readily discern-
able from Acmaea patina [= Notoacmea scutum]
and to occupy a different habitat. In 1879, Dall
reversed his position and r^arded the two as
varieties of a single species. Grant (1938) also
considered the two to be of subspecific rank and
to intergrade in the Alaskan Arctic. McLean
(1%6), Abbott (1974), and Emerson and Jacobson
(1976) consider A^. testudinalis to be limited to
Atlantic and Canadian Arctic waters with a cog-
nate, A^. scutum, in the eastern Pacific. Moskalev
(1964) considered A^. testudinalis to be present in
Arctic waters and to extend down the east coast
of Asia.

After examining shells and radulae of speci-
mens from Alaska and comparing these to Cana-
dian Arctic, eastern Atlantic, and European spec-
imens of N. testudinalis. I have concluded that N.
testudinalis occurs in the northeast Pacific and
that Ball's first account (1871) was correct as to
the species habitat and distribution. Based on
materials in the collections of the Los Angeles
County Museum and the California Academy of
Sciences, the west American distribution of this
species in Alaska is from Point Barrow (7r22'N)
(CASG #35056) to Goose Island, Icy Strait
(58°13'N) (CASG #48915) and eastward to the
Pnbilof Islands (.57°08'N, 170°15'W) (CASG
#21975). In the eastern Pacific its habitat appears
to be subtidal, although it occurs intertidally in
the eastern Atlantic and Europe. Its subtidal
habitat may contribute to its success in northern
waters, as it occurs below the level of sea ice and

low winter air temperatures. It has also been sug-
gested that this species may migrate into the sub-
tidal during the winter to avoid adverse condi-
tions (Willcox, 1905: 327). In comparison, A^.
scutum is an intertidal species, not knovm to
migrate and its northern distribution may be
limited by sea ice and adverse winter weather.
Therefore, in those areas where these two species'
geographical distributions overlap (the Aleutians
to Icy Strait, Alaska), A^. scutum and A', testudi-
nalis appear to be segregated by habitat.

The occurence of A^. testudinalis in the eastern
Pacific is similar to the distribution of Coliisella
alveus (Conrad. 1831) which occurs in both the
North Pacific and the North Atlantic.

Arguments against the presence of both A'.
scutum and A^. testudinalis as separate species in
the eastern Pacific (Dall, 1879; Test, 1938) have
been based on the presence of supposed in-
tergrades (hybrids) in the Arctic. While the
similarities of shell micro-structure and radular
morphology suggest that speciation has been re-
cent, I consider A^. testudinalis and N. scutum
sufficiently dissimilar to be considered specific.

Comparison of
Notoacmea testudinalis and Coliisella ochracea

Although the tessellate form of C. ochracea ap-
pears to be uncommon in the higher latitudes, it
can be confused with N. testudinalis (cf. Figs. 1
and 8b). Both species have similar gross color pat-
terns (Fig. 8), and in both, external sculpture con-
sists of numerous, fine, non -bifurcating riblets.

56 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

As in most forms of C. ochracea, the internal
stain of N. testudinalis does not cover the apex,
and the external apex of both is white. However,
the shell of A^. testudinaiia is larger and heavier
than that of C. ochracea, and the internal stain is
sharp and distinct; in C. ochracea, the stain is
typically obscure or lacking.

As suggested by their generic allocations, C.
ochracea and A^. testvAinalis differ in radular
structure (Figs. 9-10). The radula of C. ochracea
bears uncini; N. testudinalis lacks them. In N.
testudinalui the first and second lateral teeth are
elongate and pointed distally, rather than short
and blunt as in C. ochracea. The basal plates of
N. testudinalis differ from those of C. ochracea in
that the third lateral plates are distinct and are
located laterally from the second lateral plates.
They are also lobate rather than bi formed as in
C. ochracea. The ventral plates of both species
bear anterior processes.

ACKNOWLEDGMENTS

I wish to acknowledge Eugene V. Coan, LACM
and CASG; James H. McLean, LACM; and EJarry
Roth, CASG, for their criticism of this paper. Dr.
McLean also loaned numerous specimens. My
special thanks to Maurice Giles, CAS, who
photographed and reduced the figures. This work
was supported, in part, by SEA GRANT R/CZ-28.

LITERATURE CITED

Abbott, R. T.. 1974. American Seashells. 2nd ed.: 1-663. Van

Nostrand Reinhold, N. Y.
Brewer, B. A., 197.5. Epizoic limpets on the black turban snail,

Tegulafunebralis (A. Adams, 1855) The Veliger 17: .307-310.
Burch, J. Q.. 1946. Minutes, Cmwh. Ouh of So. Calif. 57: 1-40.
Carlton. J. T. and B. Roth. 1975 Phylum Mollusca: shelled

gastropods. In: R. I. Smith and J. T. Carlton (eds.). Light's

Manual: Intertidal Invertebrates of the Central California

Coast: 467.514. Univ. Calif.
Dall, W. H., 1871. Descriptions of sixty new forms of moliusks

from the west coast of America and the north Pacific

Ocean, with notes on others already described. AmFi: Jour.

0.»W(. 7: 9.3-160.

1879. Report on the limpets and chitons of

Alaskan and Arctic regions, with descriptions of genera and
species believed to be new. Pmc. U.S. Nat. Miis. 1: 281-.344.

. 1914. Notes on some northwest coast Acmaeas.

neNautihwsTS: 13-1.5.

1921. Summary of the marine shellbearing

moliusks of the northwest coast of America . . . Bull. i'S

Nat. Mtis. 112: 1-217.
Emerson, W. K. and M. K. Jacobson. 1976. The American

Mtiseum of Natural History Guide to Shells . . .: i-xviii.

1-482. Adfred A. Knopf
Fritchman, H. K. II. 1961. A study of the reproductive cycle

in the California Acmaeidae (Gastropoda). The Vetiger 3:

57-63.
Grant. A. R.. 1933. A revision of the California limpets of the

genus Acniaea Ek;hscholtz. Masters of Arts Thesis. Dept. of

Zool., Univ. Calif., Berkeley: 1-142.
19.38. A systematic revision of the genus Aemaea

Eschscholtz, including consideration of ecology and specia-

tion. Ph. D. Thesis. Dept. Zool.. Univ. Calif. Berkeley: l-4;fi.
Keen. A. M.. 1937. An abridged check list and bibliography of

west North American marine Mollusca: 1-87. Stanford

Univ.
Light, S. F.. et. at.. 19,54. Intertidal Invertebrates of the Cot-

tral California Coast: 1-446. Univ. Calif.
Macpherson. E.. 1971. The Marine Molluscs of Arctic Canada.

Nat. Mm. Nat. Sci.. Pubt. Oceanogr. 3: 1-149.
McLean. .1. H.. 1966. West American prosobranch Gastropoda:

superfamilies Patellacea. Pleurotomariacea and Fissurel-

lacea. Ph. D. Thesis. Dept. Zool.. Stanford Univ.: 1-262.
1969. Marine shells of southern California. Los

Angeles County Mus. Nat. Hist. Sci. Ser. 24, Zool. 11: 1-104.
Moskalev, L. I.. 1964. Distribution of Acmaeidae (Gastropoda,

Prosobranchia) in the North Pacific. Doklady. Akademii

Nauk. SSSR 158: 1221-1222. [in Russian]
Oldroyd, I. A.. 1927. The Marine Shells of the West Coast of

North America 2: 1-340. Stanford Univ. Pub., Univ. Ser.,

(jeol.Sci.
Pilsbry. H. A.. 1891. Acmaeidae. Manual of Conch. 13: 1-18.5.

Philadelphia.
Smith, A. G. and M. Gordon, 1948. The marine moliusks and

brachiopods of Monterey Bay. California and vicinity. Proc.

Calif Acad. Sci. 26: 147-245.
Test. A. R. (Grant). 1945. Ecolog>' of California Acniaea.

Ecology 26: 395-405.
1946. Speciation in limpets of the genus Acmaea.

Univ. Michigan. Contrib. Lab. Vert. Biol. 31: 1-24.
Willoox, M. A.. 1905. Biology of Acmaea testudinalis Muller.

Amer. Nat. 39: 325-a33.
Yonge, C. M.. 1962. Ciliary currents in the mantle cavity of

species of /lanwa. The Veligeri: 119-123.

NEWS
Hans Bertsch h;us been appointed Curator of EJerkeley. He has published over 30 papers on
the Department of Marine Invertebrates at the opisthobranchs, and has had extensive field ex-
San Diego Natural History Museum (P. 0. Box perience in Panama, Baja California, Hawaii and
1390. San Diego, CA 92112). Dr. Bertsch was bom California. Dr. Bertsch was previously Assistant
in 1944 in St. I^ouis, Missouri, received his Ph. D. Professor in biology at the Chaminade University
in 1976 from the University of California, of Honolulu.

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 57

TROPICAL FAUNAL AFFINITIES OF OPISTHOBRANCHS
FROM THE PANAMIC PROVINCE (EASTERN PACIFIC)

Hans Bertsch

Department of Marine Invertebrates

Natural History Museum, Balboa Park

P.O. Box 1390, San Diego, CA 92112

ABSTRACT
This is a preliminary analysis of the distribution patteitis of species of
opisthobmnchs (Gastropoda) in the eastern Pacific that are kimum to occur
elsewhere in the tropics.

The opisthobranch fauna of the Panamic pro-
vince (tropical West America) shares the greatest
number of common species with the Califomian
temperate province (Bertsch, 1973a). Since 1970.
various zoogeographic analyses of opisthobranch
faunas from other marine provinces have been
published (e.g., Franz, 1970, 1975; Thompson,
m&a.etai).

Marcus (1977) enumerated the western Atlantic
opisthobranchs, noting which species occur in
other marine provinces. She lists species common
to the Caribbean and tropical west American pro-
vinces and some amphi-Atlantic tropical forms.
This extremely useful tabulation should be used
with some reservation because certain species
listed as "circumtropical" have not yet been
reported from the Pacific coast of America (and
hence are not universally circumtropical), and
sources of the distributional data are at times
unclear.

Emerson (1978) has compiled a list of the pro-
sobranch gastropods and bivalves which are com-
mon to the Indo-Pacific and the eastern Pacific.
This preliminary note is to compliment his study,
so that a direct comparison can be made between
the opisthobranchs and the prosobranchs. It is
also intended to encourage further exchange of
information on Panamic opisthobranchs. Only
several tentative generalizations are presented
because there is still much to be learned about
the Panamic opisthobranch fauna.

Affinities

Table 1 summarizes the distribution patterns
of species of opisthobranchs in the eastern Pacific

that are known to occur elsewhere in the tropics.
North-south range distributions (i.e., affinities
with the temperate Califomian and Peruvian
provinces) are generally not included. Also omit-
ted are the pelagic Thecosomata, a group with
several circumtropical species.

Emerson (1978) and most of the writers he
cites, have divided the Panamic province into 2
main portions: the offshore islands (Guadalupe,
Revillagigedo, Clipperton, Cocos, and the
Galapagos) and the continental shelf of west
America (Gulf of California, Mexican and Central
American coastline, and the Islas Tres Marias).
The majority of Indo-Pacific prosobranch species
occur in the eastern Pacific only on the offshore
islands. By contrast, all of the opisthobranch
species known from the eastern Pacific and any
other tropical province occur on the mainland
coast. Six species occur also at the Galapagos

TABLE 1. Extra-provincial distributions of opisthobranch
species ocairrijig in the eastern Pacific. Numbers are species
with that distributional pattern.

Cephala-

Saoo-

Ana-

Nota-

Nudi-

spidea

glossa

spidea

spidea

branchia

Indii-

Pacific

0

0

1

0

3

Circum -

tropical

0

KG)

5(G)

KG)

■KP)

Carib-

bean

0

KG)

0

2(G)

5(G)

Miscel-

laneous

0

1

0

0

.3

G: One of the species (or the one species enumerated) oc-
curs in the Galapagos Islands, in addition to being present
on the mainland shelf of west America
P: All four species are pelagic

58 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

Islands. No inter-provincial tropical species is
presently known to occur only on the offshore
islands. Of course, published records of
opisthobranchs from these offshore sites are e.x-
ceedingly scarce. Nevertheless, the occurrence of
ail these inter-provincial tropical species on the
continental shelf is a very different pattern than
that known for the prosobranchs.

So far as is known, there are no strictly
Panamic forms which also occur in the Indo-
Pacific province. Excluding the circumtropicals,
species in common between these two provinces
are apparently Indo-Pacific in origin.

The inter-provincial prosobranchs are primari-
ly Indo-Pacific (48 species), with a very small
number of circumtropical (tropicopolitan is
Emerson's equivalent term) species (7). By con-
trast, there are 11 circumtropical and 4 Indo-
Pacific species of opisthobranchs in the Panamic
province.

Evolutionary relationships with species in
other provinces (including generic-level affinities)
have not been examined among the opistho-
branchs. Although sister-species are well
documented among prosobranch gastropods (Rad-
win, 1969), they have not been reported for the
opisthobranchs. Such studies would yield vital in-
formation on the origins of the Panamic opis-
thobranch fauna, and would make substantial
contributions to our knowledge of opisthobranch
phylogeny and speciation and to current concepts
of evolutionary zoogeography.

Ranges of the Individual Species

Four species of nudibranch occur cir-
cumtropically; they are all pelagic. These species
are Phylliroe biicephala "Peron and Lesueur,
1810," Cephalopyge trematoides (Chun, 1889),
Fiona pinnata (Ek;hscholtz in Rathke, 1831), and
Glaucus atlanticus Forster, 1777.

Although some of the remaining species that
comprise the data base for Table 1 may be able to
swim periodically as adults, none are pelagic
after metamorphosis from the veliger stage. In
the following paragraphs, the distribution of each
species in the Panamic province follows the loca-
tions in other zoogeographical provinces from
which it has been reported.

Sacoglossa

Lobiger souvertni Fischer, 18.56. Circumtropical
(Baba, 1974). From tropical west America, south-
ern Baja California (Isla San Jose and near Cabo
San Lucas); Santa Cruz, Nayarit, mainland Mex-
ico; Galapagos Islands (see Larson and Bertsch,
1974).

I'lil yhranchia viride (Deshayes, 1857). Carib-
bean (Ev. Marcus and Hughes, 1974: 503-506).
Gulf roast of Baja California; Nayarit, Me.xico;
Galapagos Islands (Bertsch and Smith, 1973; Fer-
reira and Bertsch, 1975).

Stiliger fuscatus (Gould, 1870). The distribution
of this species is classed as one of the "Miscel-
laneous" types: north Atlantic coast of the
United States; tip of South America; south-
eastern coast of Australia (Thompson, 1973:
240-243). Puerto Penasa), Mexiro, northern Gulf
of California (Ferreira and Bertsch, 1975). This
may be an introduced species (.sp«,sm Carlton,
1975: 17).

Anaspidea

Dolnbella auricularia (Lightfoot, 1786). Indo-
Pacific; Ecuador and Easter Island (Ev. Marcus
and Er. Marcus, 1970: 191). Gulf roast of southern
Baja California (Steinbeck and Ricketts, 1941:
171, 539-541; MacFarland, 1966: 32-37).

Aplysia dactylomela Rang, 1828. Cir-
cumtropical (Ev. Marcus and Er. Marcus, 1967:
38). Panama (Pilsbry, 1895: 88-89; Engel and
Hummelinck, 1936: 6).

Aplysia Juliana Quoy and Gaimard. 1832. Cir-
cumtropical. Northern Gulf of California (Puerto
Penasco, Sonora, Mexico) to Paita, Peru (Ev. Mar-
cus and Er. Marcus, 1967: 155-159; Keen, 1971:
808).

Aplysia parvula Morch, 1863. Circumtropical
(Thompson, 1977: 110-112). Gulf of California
(Lance, 1971: 60-63).

Dolabrifera dolabrifera (Rang, 1828). Circum-
tropical (Kay, 1964: 184-185). Northern Gulf of
California to Panama (Bertsch, 1970a; Ferreira
and Bertsch, 1975: 325); Galapagos Islands (Sphon
and Mulliner, 1972: 149).

Stylocheilus longicauda (Quoy and Gaimard,
1824). Circumtropical (Ev. Marcus and Er. Mar-
cus, 1967: 159-160). Gulf of California (Fanner,
1967; Bertsch. 1970b, and 1973b).

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 59

Notaspidea

Berthellina citrina (Ruppell and Leuckart, 1828).
Circumtropical (Thompson. 1970: 190-192; 1976a:
167-169). Southern California; throughout the
Gulf of California; Galapagos Islands (Bertsch,
1970b; Lee and Brophy. 1969; Sphon and
Mulliner. 1972: 150).

Berthellina quadridens (Morch, 1863). Carib-
bean (Thompson, 1977: 105-106). Panama Bay,
Pacific coast (Ev. Marcus and Er. Marcus, 1967:
43-44).

Pleura branchus areolatum (Morch, 1863).
Caribbean (Er. Marcus and Ev. Marcus, 1970: 55),
south-central Atlantic (Ascension Island;
Rosewater, 1975: 25), and west Africa (Edmunds,
1968: 85). Northern Gulf of California (Puerto
Penasco, Sonora, Mexico) to Panama; Galapagos
Islands (Bertsch and Smith, 1973: 169).

Nudibranchia

Berghia major (Eliot, 1903) (includes Baenlidin
amnkusana Baba, 1937). Indo-Pacific (Edmunds,
1969: 467); Oahu, Hawaii (pers. obser., August
1977). Gulf of California (Farmer, 1966; Ferreira
and Bertsch, 1975: 328-329).

Doriopsis viridis Pease, 1861. Indo-Pacific
(Young, 1967: 160-161). Southern Gulf of Califor-
nia; known only from 1 specimen (Bertsch, 1971).

SpuriUa alba (Risbec, 1928). Indo-Pacific (Ed-
munds, 1969: 465-466). Coast of mainland Mexico,
from near Guaymas, Sonora, to Punta Mita,
Nayarit (Sphon, 1971, 1978).

The four circumtropical nudibranchs are
pelagic. They were treated in a previous section.

Cadlina evelinae Marcus, 1958. Caribbean:
Brazil and Jamaica (Thompson, 1977: pit. 2; Ev.
Marcus, 1977: 9). Pacific coast of Baja California;
Gulf of California (Ev. Marcus and Er. Marcus,
1967: 168-170).

Dendrodoris krebsii (Morch, 1863). Caribbean
(Meyer, 1977: 304). Northern Gulf of California to
Panama; Galapagos Islands (Bertsch, 1973b: 109;
Meyer, 1977).

Pkidiana lynceus Bergh, 1867. Caribbean (Ed-
munds, 1964: 16-18). Pacific coast of Panama Ca-
nal Zone (Ev. Marcus and Er. Marcus, 1967: 111-
112).

Spurilla neapolitana (Delle Chiaje, 1823).
Caribbean and Mediterranean (Ev. Marcus and

Er. Marcus, 1967: 118-119). Gulf of California
(Alex Kerstitch, pers. comm.).

Tayiiva ketos Marcus and Marcus, 1967. Carib-
bean (different subspecies; Er. Marcus and Ev.
Marcus, 1970: 65-66). Northern Gulf of California
to Bahia de Banderas, Nayarit, Mexico (Ferreira
and Bertsch, 1975: 327).

The remaining 3 species of nudibranchs have
"Miscellaneous" distributions (i.e., they are not
Panamic-Indo-Pacific, Panamic-circumtropical,
nor Panamic-Caribbean).

Aeolidiella takanosimensis Baba, 1930. Japan
(Baba, 1930); Mediterranean (Schmekel, 1968:
122-123); Oahu, Hawaii (pers. obser.; 1 specimen,
Wailupe, 19 May 1977; 7 specimens, Earthwatch
team members, Hauula, 14 June 1978). Southern
California (Sphon, 1971); Bahia San Marte, Baja
California del Sur, Mexico (Ferreira and Bertsch,
1975: 329). This is possibly an introduced species
to Hawaii and the eastern Pacific.

Coryphellina rubrolineata O'Donoghue, 1929.
Suez Canal, Australia, Japan, Brazil. San
Agustin, Sonora, Mexico (Ev. Marcus and Er.
Marcus, 1970: 210-211).

Limenandra nodosa Haefelfinger ^and Stamm,
1958. Mediterranean; Caribbean. Bahia Las Cruces,
Baja California del Sur, Mexico (Bertsch, 1972).

ACKNOWLEDGMENTS

I am grateful to The Center for Field Research
for a grant that enabled me to collect specimens
in Hawaii during June 1978. I thank especially
the following members of the Hawaiian Mollusks
1978 Earthwatch team who collected specimens
reported in this paper: Brian McElaney, Steve
Norton, Larry Targett, Gregg Wilson, and Dr.
Mel Brophy. I also thank Alex Kerstitch for sup-
plying data, and Dr. William K. Emerson for
comments.

LITERATURE CITED

Baba, Kikutaro. 1930. Studies on Japanese nudibranchs (3). A.

Phyllidiidae. B. Aeolididae. Venus 2(3): 117-125; pi. 4; 5

text figs. (10 December 1930)
. 1974. Some comments on Lobxger souverbii

Fischer. 1856, re-identified, of Japan (Opisthobranchia:

Sacoglossa: Lobigeridae). The Veliger 16(3): 253-257; 3 text

figs. (1 January 1974)
Bertsch. Hans. 1970a. Dolabrifera dolabrifera (Rang, 1828):

Range extension to the eastern Pacific. The Veliger 13(1):

110-111; 1 text fig. (IJuly 1970)

60 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

. 1970b. Opisthobranchs from Isla San Francisco,

Gulf of California, with the description of a new species.
Gmtrib. Sri.. Santa Barbara Mm. Nat. Hist, t 1-16; 13 text
figs. (1 December 1970)

. 1971. Natural histun' and occurrence of

opisthobranchs of Las Cruces, Baja California, Mexico, and
vicinity. Abstr. Proc. Third Ann. Meet. West. Soc. Malac.,
The Echo 3: 16. (7 March 1971)

_. 1972. Two additions to the opisthobranch fauna

of the southern Gulf of California. The Veliger 15(2):
103-106; 1 pi.; 3text figs. (1 October 1972)
1973a. Zoogeography of opi.sthobranchs from

tropical west America. Abstr. Proc. Fifth .Ann. Meet. West.
Soc. Malac.. Vie Echo 5: 47-.54. (.5 March 1973)

1973b. Distribution and natural history of

opisthobranch gastropods from Las Cruces. Baja California
del Sur. Mexico. The Veliger 16(1): 105-111; 2 maps. (1 .July
1973)
and Alberic A. Smith. 1973. Observations on three

opisthobranchs (MoUusca: Gastropoda) of the La Paz area.
Baja California, Mexico. Southwestern Naturalist 18(2):
165-176; 1 text fig. (29 June 197,3)

Carlton. James T. 197.5. Introduced intertidal invertebrates.
In: R. I. Smith and J. T. Carlton (ed.). Light's Manual: In-
tertidal Invertebrates of the Central California Coast.
University of California Press, pp. 17-25 (8 May 197.5)

Eximunds. Malcolm. 1964. Eolid moUusca from Jamaica, with
descriptions of two new genera and three new species. Bull
Mar Sri. Gulf Carib. 14(1): 1-.32; 16 te.xt figs. (19 March 1964)

1968. Opisthobranchiate mollusca from Ghana.

Proc. Malac. Soc. London 38(1): 83-100; 12 text figs. (April
1968)

1969. Opisthobranchiate mollusca from Tanzania.

I. Eolidacea (Eubranchidae and Aeolidiidae). Proc. Malac.

Soc. Lond. 38(.5): 451-469; 10 text figs. (August 1969)
Einerson. William K. 1978. Mollusks with Indo-Pacific faunal

affinities in the Eastern Pacific Ocean. The Nautilus 92(2):

91-96. (27 April 1978)
Engel, Hendrick, and P. Wagenaar Hummelinck. 19.36. Ueber

westindische Aplysiidae und Verwandten anderer Gebiete.

Capita Zoologica 8(1): 1-76; 43 text figs.
Farmer, Wesley M. 1966. Range extension of Berghia

amakusana (Baba) to the east Pacific. The Veliger 9(2): 251;

1 text fig. (1 October 1966)
. 1967. Notes on the opisthobranchia of Baja

California. Mexico, with range extensions. —II. The Veliger

9(3): ^0-:}42; 1 text fig. (1 .January 1967)
Ferreira, Antonio J., and Hans Bertsch. 197.5 Anatomical and

distributional observations of some opisthobranchs from the

Panamic faunal province. The Veliger 17(4): 323-330; 3 pis.;

1 text fig. (1 April 1975)
Franz, David R. 1970. Zoogeography of northwest Atlantic

opisthobranch molluscs. Mar. Biol. 7(2): 171-180; 5 text figs.

(October 1970)
. . 197.5. An ecological interpretation of nudibranch

distribution in the northwast Atlantic. The Veliger 18(1):

79-83; 3 te.xt figs. ( I .luly 1975)
Kay. E. Alison. 1964. The Aplysiidae of the Hawaiian Islands.

Proc. Malac. Soc. Lond. 36(3): 173-190; pi. 8: 1 text fig.

(December 1964)

Keen, A. Myra. 1971. Sea Shells of Tropical West America:
marine mollusks fi-om Baja California to Peru. Stanford
Univ. Press, Stanford, Calif xiv -I- 1066 pp.; ca. 4000 figs.;
22(.«lor pis. (1 September 1971)

I.ance. .James R. 1971. Observations on the sea hare Aplysia
parvula (Gastropoda; Opisthobranchia) from the Gulf of
California. The Veliger 14(1): 60-63; 4 text figs. (1 July
1971)

Larson, Mary, and Hans Bertsch. 1974. Northward range ex-
tensions for Lobiger smiverhii (Opisthobranchia: Sacoglossa)
in the eastern Pacific. The Veliger 17(2): 22.5. (1 October
1974)

Lee, Richard S., and Patrick Brophy. 1969. Additional
bathymetric and locality data for some opisthobranchs and
an octopus from Santa Barbara County, California. The
Veliger 12(2): 220-221. (1 October 1969)

MacFarland. Frank Mace. 1966. Studies of opisthobranchiate
mollusks of the Pacific coast of North America. Mem. Calif
Acad. Sci. 6: xvi -I- 546 pp.; 72 pis. (8 April 1966)

Marcus, P'rnst, and Eveline du Bois-Re.vmond Marcus. 1970.
Opisthobranchs from Curasao and faunistically related
regions. Stud. Fauna Curacao Carib. Isl. 33(122): 1-129; 160
text figs.

Marcus, Eveline du Bois-Re>'mond. 1977. An annotated
checklist of the western Atlantic warm water opistho-
branchs. Jm^r. Moll. Studies Suppl. 4: 1-22 (November 1977)

, and Helen P. I. Hughes. 1974 Opisthobranch

mollusks from Barbados. Bull. Mar. Sri. 24(3): 498-532; 56
text figs. (27 November 1974)

, and Ernst Marcus. 1967. American opisthobranch

mollusks. Studies in Tropical Oceanography (U'niv. Miami

Inst. Mar. Sci., Miami. Florida), no. 6: viii -t- 256 pp.; figs.

1-155 -I- 1-95. (22 December 1967)
1970. Some gastropods from Madagascar and west

Mexico. Malacologui 10(1): 181-223; 93 text figs. (14

November 1970)
Meyer. Kaniaulono B. 1977. Dorid nudibranchs of the Carib-
bean ojast of the Panama Canal 7/me. Bull. Mar. Sri. 27(2):

299-.307; 4 te.xt figs. (27 April 1977)
Pilsbry. Henry A. 1895-1896. Manual of Concholoyy. \'ol. 16:

262 pp.; 74 pis.
Radwin, George E. 1969. A recent molluscan fauna from the

Caribbean coast of southeastern Panama. Ti'ans. San Diego

Soc. Nat. Hist. 15(14): 229-236; 1 te.xt fig. (27 June 1969)
Rosewater. .Joseph. 197.5. An annotated list of the marine

mollusks of Ascension Island. South Atlantic Ocean.

Smithsonian C(mtrib. Zool. 189: iv -I- 41 pp.; 24 te.xt figs.

(130 May 1975)
Schmekel, Luise-Renate. 1968. Ascoglossa, Notaspidea und

Nudibranchia im litoral des Golfes von Neapel. Rev. Suisse

Zool. 75(1): ia3-155; 21 text figs. (March 1968)
Sphon. Gale G. U)71. New opisthobranch records for the

eastern Pacific. Tlir Vrluirr 13(4): :i58-:«t. (1 April 1971)
. 1978. Additional notes on Spurilla alba (Risbec,

1928) (Mollusca: Opisthobranchia). The Veliger 21(2): 305. (1

October 1978)
and David K. Mulliner. 1972. A preliminary list

of known opisthobranchs from the Galapagos Islands col-
lected by the Ameripagos Expedition. The Veliger 15(2):
147-1.52; 1 map (I October 1972)

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 61

Steinbeok. John, and Edward F. Ricketts. 1941. Sea ofCoriez.

Tne \'ikinR Press. New York, x + .598 pp.; 40 pis.

(DeceniljerlWl).
Thompson. Thomas E. 1970. I>;ast^rn Australian Pleurobranch-

omorpha (Gastropoda. Opisthobranchia). Jour. Zaal.. London

160(2): 173-198; 1 pi.; 11 text figs. (16 February 1970)
1973. Sacoglossan gastropod molluscs from

eastern Australia. Proc. Malac. Soc. Lond. 40(4): 239-2.51; 3

te.xt figs. (April 1973)
. 1976a. Biologj- of opisthobranch molluscs. Vol. 1.

1976b. Introduction: Zoogeography of nudi-

branchs. Jour. Moll Shulies. 42(2): 295-:3()2 (pagination in-
cludes several papers by various authors). (.August 1976)

1977. Jamaican opisthobranch molluscs I. Jnur.

The Ray Society, London. 207 pp.; 21 pis.; 106 text figs.

Moll. Studies 43(2): 93-140; 3 pis.; 32 text figs. (July 1977)

Young, David K. 1967. New records of nudibranchia
(Gastropoda: Opisthobranchia: Nudibranchia) from the cen-
tral and west-central Pacific with a description of a new
species. The Veliyer 10(2): 1.59-173; 18 text figs. (1 October
1967)

A NOTE ON THE DISTRIBUTION AND FOOD PREFERENCE OF
CADLINA LAEVIS (NUDIBRANCHIA: CHROMODORIDAE)'

Melissa A. Barbour

1839 9th Street
Alameda. CA 94501

ABSTRACT
The distribution and food preference of the nudibranch, Cadlina laevis (Linnaeus.
1767) are discussed. This species has an amphiatlantic distribution from Cape Cod
on the American coast to the Mediterranean on the European coast. It appears to
feed on the soft, dendroceratid sponge, Halisarca dujardini Johnston.

The dorid nudibranch Cadlina laevis (Linnaeus,
1767) has an amphiatlantic distribution. Lemche
(1938) reported the distribution of C. laevis ". . .
from the Gulf of Mexico, Greenland, several
localities in the Arctic Sea, the Faroes, the
Shetlands, the whole coast of Norway, south-
wards along the west coasts of Europe, and from
the Mediterranean." The inclusion of the Gulf of
Mexico in this list is probably an error since
Franz (1970) reported the southern limit of this
boreo-subarctic species to be Cape Cod, Massa-
chusetts. There are no reports of C. laevis from
the Gulf of Mexico in the recent literature. It is
probable that Lemche meant the "Gulf of Maine"
where this species does occur. While a student at
Northeastern University, Boston, Massachusetts, I
made field observations on this species at East-
port, Maine, in August and September of 1969
and 1970, and carried out laboratory studies at

'. Osntribution no. 69. Marine Science Institute, Northeastern
University. Nahant, Massachusetts.

the Marine Science Institute at Nahant, Massa-
chusetts.

FIELD OBSERVATIONS

C. laevis is found in the lower intertidal to
subtidal regions of exposed rocky coastal areas. It
was observed by me under rocks at approximate-
ly -3.0 feet below mean low water (MLW). The
habitat consisted of boulders resting on bedrock
around and imder which small amounts of sandy
mud were trapped. Some algal growth was pre-
sent on the boulders. Other invertebrates, in-
cluding brachiopods, colonial and solitary
tunicates, and sponges, were also attached to the
underside of these boulders. TTie unspiculated
dendroceratid sponge, Halisarca dujardini;
Johnston, was commonly found encrusting the
undersides of these boulders. C. laevis was
observed in close proximity to this sponge, being
either within a small cleared area at the center

62 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

of a Halimrca mat or at the edge of it. The
anterior mantle of the nudibranch typically cov-
ered the edge of the sponge mat. When the nudi-
branch was removed a concavity in the edge of
the sponge was seen. This concavity conformed to
the size and shape of the anterior portion of the
dorid. The nudibranch was only rarely found on
rocks without the sponge.

LABORATORY OBSERVATIONS

Specimens of C. laevis were kept in laboratory
aquaria for up to 10 months without any obvious
food source. During this time the animals were
observed to release fecal strands and to spawn.
Animals dissected during this period had a brown
material in the stomach. I believe this material
was alagal slime from the sides of the aquaria on
which the nudibranchs were able t*j maintain
themselves. Eggs were deposited in early spring.
The young hatched after approximately 2 months,
but did not mature. When //a/ isarra -encrusted
rocks were placed in the aquaria the nudibranchs
were observed to feed on the sponge (M. P. Morse,
pens, cornm.).

DISCUSSION

Two of Swennen's (1961) three criteria for
determining preferred food of nudibranchs were
met in this study: (1) the animal was found in
the field in close conjunction with the probable
food; and (2) the animal fed on the probable food
in the laboratory. The third criterion, the main-
tenance of the animal on the preferred food in
the laboratory, was not met in this study.

There are, in addition to the above field and
laboratory observations, morphological and

anatomical indications that C. Inei-U feeds on soft
sponges. The body is oval, with a broad foot and
wide radula; the mouth lacks true mandibles. The
digestive tract lacks a buccal pump, has a
reduced caecum, and there is a reduction in the
number of gland cells throughout the tract (Bar-
bour, 1;)71). These modifications have been pre-
viously described for feeders of soft sponges by
Forrest (1953) and by Thompson (1962).

ACKNOWLEDGMENTS

I wish to thank Dr. M. P. Morse and Dr. N. W.
Riser for their help and support during the
preparation of this manuscript and Dr. Welton L.
Lee, David R. Lindberg and James E. Sutton for
their reviews and comments on it. Part of this
study was submitted in partial fulfillment of the
requirements for a MS degree at Northeastern
University.

LITERATURE CITED

Barbour. M. A. 1971. The functional morphology of the
digestive tract of the dorid nudibranch. Cadlina laevis
Bergh, 1879 [sic]. Unpublished MS thesis. Northeastern
University, Boston, Massachusetts. 64 pp.

Forrest, J. E. 1953. On the feeding habits and morphology and
mode of function of the alimentary canal in some littoral
dorid Nudibranchiata Mollusca. Proc. Linn. Snr. London
164(2): 225-2a5.

Franz, D. R. 1970. Zoogeography of Northwest Atlantic
opisthobranch molluscs. Afar. Biol. 7: 171-180.

Lemche, H. 1938. Gastropoda opisthobranchiata. 77i€ Zoology
of Iceland 4(51): 1-54.

Swennen, C. 1961. Data on distribution, reproduction and
ecolog>' of the nudibranch molluscs occurring in the
Netherlands. A'eMer/(i«(is ,/. Sea Rejteuirh 1: 191-240.

Thomiwon, T. E. 1962. Grazing and the life c.vcle of British
nudibranchs. In: Grazing in Terr&strial and Marine En-
vironments, Ed. D. J. Crisp. Sijmp. British Ecol. Soc., 4:
275-297.

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• ••I

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 63

CATINELLA PARALLELA. A NEW SUCCINEIDAE (PULMONATA) FROM

MIDWESTERN UNITED STATES

Dorothea S. Franzen

Illinois Wesleyan University
Bloomington, Illinois 61701

ABSTRACT
Catinella parallela, a new sppcies of Siwcineidae. mid its reproductive oryans.
chninioiiomeii. shell and detailed habitats are described. The knoum geographic
range extends from western Elinois to western Indiana, between 38°10' - J^O'SO'N
latitude. This species was taken from three types of habitats.

In the coui-se of my field studies on succineid
gastropods in the midwestem states I have found
a large, hitherto undescribed species.

Catinella parallela n. sp.

Description of Holotype: Shell: amber-colored,

translucent, imperforate, elongate-ovate, com-
posed of three and one-third inflated whorls
separated by a deeply incised suture; height 10
mm, width 6.1 mm. A knoblike nuclear whorl
tops the acute spire; whorls increase rapidly in
size resulting in a tumid ultimate whorl; nuclear

B

FIG. 1. A, B, Hntotype of Catinella parallela, n. sp. (Height.
10 mm). C. Paratype of Catinella parallela n. sp.. one-half
mile X. White River. Knox County. Indiana (Height 11.7
mm). D. Paratype of Catinella parallela n. sp.. Pere Mar-

quette State Park, Jersey County. Illinois (Height 12.0 mm).
E. F. Paratyi>e of Catinella parallela n. sjh. AVw Hardin,
Greene County. lUinoi.': (Height 1-1.2 mm.)

64 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

whorl finely granular; irregularly-spaced longi-
tudinal striations, fine on the lower half of the
nuclear whorl, increasing gradually, becoming
coarser towards the aperture; ovate aperture oc-
cupies nearly seven-tenths of height of shell
(Table 1). Sharply-edged peristome very fragile;
very thin callus discernible on ultimate whorl
above the aperture; amber-colored columella
follows inner border of peristome and curves as it
disappears into the ultimate whorl (Fig. 1, A).

Body and Mantle Surfaces: Surface of head
and body wall cream-colored, coarsely and ir-
regularly tuberculate; pigmentation of dorsal
body surface consists of bands of dark flecks ex-
tending from anterior end of head to junction of
mantle and the body wall; mid-dorsally on head
pigmentation forms a triangle, narrowing to a
band between the superior (posterior) tentacles,
dividing and continuing as a double band mid-
dorsally the length of the body; the median
triangle flanked on either side by a dark band,
bending medially around the superior tentacles,
paralleling the dorsal pair the length of the body;
median triangle flanked on either side by a dark
band which bends medially around the superior
tentacle to parallel the mid-dorsal pair the length
of the body; surface of both pairs of tentacles
flecked; pigmentation of lateral body wall form-
ing a broad horizontal band.

The genital aperture, about 0.5 mm in length,
surrounded by a white lip, situated on anterior
right-hand side of body. On either side a pedal
groove, continuous from labial palp to posterior
tip of body, separates foot from lateral body wall;
pedal groove paralleled by a less pronounced
suprapedal groove. Shallow, vertical grooves in-
cise the suprapedal and pedal grooves, margin of
foot and the broad pigmented band. These ver-
tical grooves produce shallow scallops along the
margin of the foot especially when the animal is
in a somewhat contracted state. The sole of the
foot is cream -colored and unpigmented.

The mantle collar is flecked overall. From
anterior margin of mantle narrow bands of pig-
ment, distinct near edge of collar, merge forming
streaks over mantle surface. The kidney is out-
lined by a dark band.

Holotype: Catalogue no. FMNH 201444;
Paratypes nos.: FMNH 201445, FMNH 201446,

Molluscan Collection, Field Museum of Natural
Histor>', Chicago, Illinois. Additional paratypes
are in the private collection of the author.

T)fncripti(in of Paratifpes: Shell: (Fig. 1, C-F)
Shells of mature snails, attaining a height of 15.2
mm, are comprised of 3 1/4 to 3 3/4 inflated
whorls. Dimensions of the three largest shells,
number of shells measured, and the median of
each of the nine series measured, are recorded in
Table 1. The range of the greatest height of the
series of shells included in this study is from 10.2
to 15.2 mm, and the range of the greatest width
is from ■6.0 to 8.28 mm. The largest apertures of
the shells of the nine series occupy from 65.8 to
72.0 percent of the entire height of the shell.
Other dimensions and relative dimensions are to
be noted in Table 1. T^e largest shells were taken
from the flood plain of the Illinois River, New
Hardin, Green County, Illinois (Field #269) on
June 22, 1966. To date I have not found mature
snails sundving beyond the month of July.

Reproductive Organs: (Fig. 2) The albumin
gland (A, C - AG) triangular in form, composed

of fine acini, is enclosed within a thin, tran.'^-
parent sheath. The elongate, sube(iually biiobed
seminal vesicle (A, C - SV) is enclosed with-
in a thin, transparent, pigmented sheath. The
darkly pigmented hermaphroditic duct (A, C -
HD) and the bilobed seminal vesicle join to form
the fertilization sac (A, C - FS) from which
diverge the oviduct (OD) and the sperm duct (SD)
which leads into the prostate gland (PG). The
oval prostate gland, enclosed by a thin,
transparent, pigmented sheath, is composed of
acini which are coarser than those of the albumin
gland. The length of the prostate gland exceeds
that of the albumin gland (A, C). As the vas
deferens approaches the penis from the prostate
gland it follows the penis along its dorsal surface.
As it enters the distal end of the penis it enlarges
to form the epiphallus (B, C - EP) which enters
the unsheathed penis (P) terminally. The penis
enlarges immediately into a cylindrical form. The
penial appendage (B, C - PA) whose base is
almost one-half the length of the penis, originates
subterminally where the penis joins the genital
atrium (B, C - GA). The appendage expands
horizontally to equal about two-thirds of the

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 65

TABLE 1. Dimensioris of shells o/Catinella paiallela, ii. »p. The measiirements are of the three largest shells of each of the 9 series
(6 liicntities) as indicated, hi the J,lh column of iieasnrentents are listed the mtios of the uidth of the shell over its height. In the
last S columns air listed the ratios of the height of the aperture over the height of the shell, iridth of aperture over width of shell
width ofapeiture oiwr height of aperture.

No.

of

Width/

Height of

Width of

H. Ap./

W. Ap./

W. Ap./

Whorls

Height

Width

Height

Aperture

Aperture

H. Shell

W. Shell

H. Ap.

Holotype

3

1/3

10. 0 mm

6. 1 mm

.61

6.7 nun

4.1 mm

.67

.67

.61

Type Locality

3

1/3

10.2

6.4

.62

7.4

4,5

.72

.70

.61

Field «4S8

3

1/3

9.5

5.6

.59

6.4

3.8

.67

.68

.59

Floodplain. Wabash R.

,

White Co. , Illinois

June 20, 1977

Range (6 shells)

3
3

1/3

7.5 -
10.2

4.7-6.4

.56-. 62

5.1-7.4

3.2-4.5

.66-. 72

.67-.

73

.59-. 62

Median

9.5

5.6

.59

6.4

3.8

.67

.68

.59

Field •458

3

1/2

11.91

6.7

.563

7.89

5.51

.662

.822

.698

Floodplain, Wabash R.

, 3

1/2

11.25

6.33

.563

7.27

5.00

.646

.790

.688

Wiite Co. , I llinois

3

1/3

11.15

7.00

.628

7.50

5.38

.623

.769

.717

June 5, 1976

Range {12 shells)

3
3

1/2

6.3 -
11.91

3.61-7.0

.53-. 628

3.94-7.89

2.78-5.51

.623-. 711

. .672-

.869

.606-. 717

Median

10.26

6.24

.573

6.86

4.42

.670

.798

.684

Field »461

3

1/2

14.29

7.44

.521

8.95

5.76

.626

.774

.644

One-half mi. S of

3

1/2

13.27

8.80

.663

8.50

5.74

.640

.652

.675

White River, Knox Co.

, 3

1/2

13.04

7.85

.602

•^.85

5.20

.602

.662

.662

Indiana

June 6, 1976

Range (8 shells)

3

3

1/3-

1/:

9.82-
14.29

6.28-8.80

.521-. 663

6.53-8.95

4.48-5.76

.585-. 678

.652-

.80

.662-. 735

Median

12.70

7.20

.640

7.56

5.44

.637

.713

.684

Field »461

3

1/2

10.6

6.0

.56

6.7

4.4

.63

.73

.65

One-half mi. .N of

3

1/3

10.5

6.10

.58

6.8

4.5

.64

.73

.66

White River, Knox Co.

, 3

1/3

9.8

5.7

.58

6.0

3.5

.61

.61

.58

Indiana

June 21, 1977

Range (28 shells)

3
3

1/4-
1/2

8.2-10.6

4.8-6.1

.49-. 64

5.1-6.8

3.4-4.5

.56-. 70

.60-.

77

.56-. 66

Median

9.5

5.6

.59

6.1

3.7

.64

.67

.61

Field "462

3

1/2

12.84 mm

7.25 mm

.565

7.83 mm

5.26 mm

.610

.726

.672

10 mi. N Vincennes,

3

1/2

10.00

6.09

.609

6.28

4.17

.628

.685

.664

Knox Co. , Indiana

3

1/3

9.47

5.65

.597

S.78

3.95

.610

.699

.683

June 6, 1976

Range (20 shells)

3
3

1/3-
1/2

3.89-
12.84

2.50-7.25

.474-. 643

2.56-7.83

2.0-5.26

.528-. 658

.641-

.767

.576-. 843

Median

8.03

4.7S

.597

4.81

3.27

.577

.688

.684

Field »187

3

1/2

12.4

7.5

.60

8.6

5.4

.69

.72

.62

Pere Marquette State

3

1/3

12.2

7.0

.57

7.8

4.6

.64

.65

.59

Park, Jersey Co. .

3

1/2

11.7

6.7

.57

7.5

4.3

.64

.64

.57

Illinois

June IS, 1954

Range (7 shells)

2
3

3/4-
1/2

8.9-

12.4

5.1-7.5

.56-. 61

6.2-8.6

3.7-5.4

.60-. 69

.64-.

72

.57-. 66

Median

11.6

6.7

.57

7.S

4.6

.65

.70

.60

Field •269

3

3/4

13.23

8.20

.620

8.65

5.61

.654

.684

.649

New Hardin,

3

1/2

13.05

7.80

.598

8.60

5.68

.659

.728

.660

Greene Co., Illinois

4

13.00

7.74

.595

8.30

5.00

.638

.646

.602

July 11, 1964

Range (25 shells)

3
4

1/3-

10.10-
13.23

5.60-8.20

.518-.645

6.22-8.65

4.36-S.68

.606-. 711

.631-

.841

.602-. 723

Median

11.60

6.95

.60

7.59

4.91

.653

.701

.652

Field 1269

3

1/2

15.20

8.28

.545

9.60

6.40

.632

.773

.667

New Hardin,

3

1/2

13.15

7.35

.559

8.55

S.95

.650

.810

.696

Greene Co. , Illinois

3

1/2

12.82

7.40

.577

8.20

5.17

.640

.699

.630

June 22, 1966

Range (9 shells)

3

1/3-

10. so-

3

1/2

ls. 30

6.05-8.28

.527-. 630

6.95-9.60

5.05-6.80

.618-. 689

.699-

.863

.630-. 777

Median

12.70

7.22

.576

8.20

5.36

.640

.810

.696

Field 11445

3

1/3

12.15

6. 85

.564

7. SO

4.47

.617

.653

.596

0.8 mi. S Nutwood,

3

1/3

11.51

6.6

.573

8.0

4.92

.695

.745

.615

Jersey Co. , Illinois

3

1/3

11.45

7.0

.611

7.50

4. 52

.657

.646

.603

June 1, 1975

Range (14 shells)

3
3

1/3-
1/2

8.42-
12.15

S. 08-7. 00

.S66-.641

5.20-8.0

3.5S-4.92

.610-. 708

.646-

.80

. 596- . 72

Median

10.5

6.12

.603

6.95

4.45

.657

.742

.648

66 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

FIG. 2. Reproductive organs o/Catinella parallela n. sp. AG.
albumin gland: EP, epiphalhis: FS, fertilization sac: GA.
genital atrium: HD, hermaphroditic duct: OD, oviduct: P.
penis: PA, penial appendage: PG, prostate gland: PRM, penial
retractor muscle: SD, sperm duct: SP, spermaiheca: SPD,
spermathecal duct; SV, semina/ vesicle; VA, vagina; VD, ytw
de/er«7is.

length of the penis — the expanded portion paral-
lels the penis (A, C). The vertical dimension of
the appendage is almost twice that of the body of
the penis. The internal walls of the penis and of
the appendage are folded forming very prominent
ridges projecting into the lumen. The internal
foldings of the appendage can be noticed exter-
nally by markings as indicated (B, C). Fibers of
the broad, stout penial retractor muscle insert
mainly onto the base of the penial appendage;
lesser fibers insert onto the penis and onto the
epiphallus(B,C-PRM).

The globular spermatheca (Fig. 2, C - SP) is
connected to the vagina by a stout spermathecal
duct (SPD) which enlarges as it approaches and
enters the vagina. The short vagina expands as it
opens into the genital atrium (B - GA).

The Radula: Radulae of seven paratypes of
three localities were stained and mounted. The
number of rows of teeth occurring on the radulae
examined range from 84-90 (Table 2). There are
few teeth to a row on the anterior-most rows; the
number increases rapidly posteriorly.

The number of marginals and laterals of rep-
resentative rows of the seven radulae are re-
corded in Table 2. Although there is an indi-
vidual variation of the radulae and also of the
rows of teeth of a radula, the ratio of marginals
to laterals is approximately 1:1 Such a ratio is
characteristic of the genus as noted by Quick to
be true of Catinella (Sticcinea) arenaria ("B.-Ch.")
(Quick. 19.33, Fig. 4, p. 296).

The structural details of the individual teeth
resemble those of the genus as described for
European species by Quick (ibid). The charac-
teristics of the teeth are described below and il-
lustrated in Fig. 3, A. The central tooth (C) bears
a broad basal plate having a posterior, serrated
margin flanked on either side by a rounded boss.
Ihe pointed mesocone extends downward to a-
bout the lower third of the basal plate. A short,
I)ointed ectocone flanks the mesocone on either
side.

The laterals (L-L) have a large, pointed meso-
cone which, like that of the central tooth, extends
downward to about the lower third of the basal
plate. A small, pointed endocone is present. The
singly pointed ectocone is sometimes divided into
two cusps; this is especially true of the more
lateral teeth.

The marginals (L-M) smaller than the laterals,
have a basal plate which is broader than long;
this is especially true of the outermost marginals
(Fig. 3). The small endocone is pointed; the
pointed mesocone extends to the base of the basal

T.\BLE 2. Fonnulae of representative rows of teeth of Cati-
nella parallela new species.

No. of

Rows

Statloo

Slide

of le

eth

Row

H

I.

L

H

Field Ho.

1.1.5

A

S6

1.7

15

-

10

-

1 -

IJ

.

15

Jersey County,
Illinois

50

1)

-

12

-

I -

13

-

15

5J

11.

-

11

-

I -

12

-

15

65

15

-

10

-

I -

n

•

15

Field Ko.

269

A

90

il

10

_

15

_

_

16

_

7

Seat Hardin,
Illlnoia

J6

11

-

15

-

-

11.

-

9

B

88

2i

11.

-

10

-

-

11

-

10

1.6

15

-

9

-

-

10

-

12

C

88

1.7

15

-

10

-

-

11

-

12

0

92

^9

10

-

-

-

12

-

12

5!

15

-

-

-

11.

-

11

Field No.

<.61

A

81.

1.5

11

_

-

15

_

11

Knox Coun
Indiana

tj.

55

11

-

- !

10

-

12

61.

15

-

- 1

15

-

15

B

88

}!•

11.

-

- 1

11.

-

11.

66

11.

-

- 1

12

-

16

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 67

plate. The ectocone of the inner-most marginals is
divided into two, while the outermost is divided
into three cusps.

The basal plates of the marginals are short and
broad which is a distinctive feature of the genus
Catinella as observed by Quick (1933, Fig. 4). The
basal plates of the marginals of the radula in the
genus Oxyloma are long and tapering as reported
of Oxyloma (Succinea) pfeifferi ("Rossm.") by
Quick (ibid, Fig. 1). This feature of the radula
was observed in other species of Oxyloma by
Franzen (1963, Fig. 1; 1966, pp. 64-65; 1969, Fig.
1; 1973, Fig. 4). The basal plates of the marginals
of the genus Succinea are intermediate in length
(Quick, 1933, Figs. 2, 3; and Franzen, 1959, Fig. 3;
1971, Fig. 3).

The Jaw. The amber-colored jaw is illustrated
in Fig. 3, B. Anteriorly the collar has a median
fold flanked on either side by smaller lateral
folds. Posteriorly the collar bears a broad, median
indentation.

Chromosome Number. Ovotestes of Catinella
parallela were squashed and stained with orcein.
Examination of the stained chromosomes in
meiotic metaphase revealed the haploid number
of six. This small number is characteristic of the
genus Catinella (Patterson, 1971, Table 1.). This
contrasts with the haploid number of nineteen of
several species of Oxyloma: Oxyloma deprimida
Franzen (Franzen, 1973, Fig. 1, and p. 68); 0.
retusa (Lea), 0. haydeni (W. G. Binney) and 0.
salleana (Pfeiffer) (Franzen, 1966, p. 67). The
haploid chromosome number of eighteen is char-
acteristic of Succinea vaginacontorta Lee
(Franzen, 1971, p. 141) and other species of Siw-
cinea of continental USA. (Patterson, 1971, Table

1).

Geographic Distribution and Habitats. The
known geographic range of Catinella parallela ex-
tends from the flood plain of the Illinois River in
Greene and Jersey counties in western Illinois,
across the state to the banks of the Wabash River
in White County in eastern Dlinois, and to Knox
County in western Indiana. The eight localities
where I have found C parallela represent three
types of ecological habitats, namely: (1) a wooded
flood plain of a river; (2) a slough with stands of
plants including Typha sp. (cattails), Sagittaria
latifolia Willd. (arrowhead), Eleocharis sp. (spike

rush). Polygonum ineum Muhl (water smart-
weed), Rhus radicans L. (poison ivy), and Spar-
tina sp. (sawgrass); (3) roadside ditch supporting
a stand of Typha sp.

Locality 1, Type Locality: Field No. D.S.F. 458;
western edge of the flood plain of the west side of
the Wabash River, below the bridge of Illinois
Hwy. 14 (formerly U.S. Hwy 460), 7 miles E
Crossville, White County, Illinois. The flood plain
is a woodland of predominantly Acer sac-
charinum L. (silver maple), Gleditsia triacanthos
L. (honey locust), and Populus deltoides Marsh
(cottonwood). Catinella parallela lives on the
shaded damp ground, on rotting wood, and on
dead leaves on the ground.

Locality 2, Field No. D.S.F. 459; twelve miles E
Princeton, Gibson County, Indiana, Indiana Hwy.
64, one-half mile E Wabash River, in a lowland
wooded area of predominantly Acer saccharinum
L. One individual of Catinella parallela was
under a piece of cardboard in a small pile of rub-
bish.

Locality 3, Field No. D.S.F. 460; flood plain of
the Patoka River, Patoka, Gibson County, In-
diana, in a wooded area of predominantly Acer
saccharinum L. and Populus deltoides Marsh.
Two individuals of Catinella parallela were found
on damp ground of an exposed area.

Locality U, Field No. D.S.F. 461; one-half mile
N White River, a roadside ditch and slough
alongside Orville Road, west off of U.S. Hwy. 41,
Knox County, Indiana. Typha sp. grows in the

mm

FIG. 3. k: Rfspresentative radvla teeth o/ Catinella parallela
/(. sp. C, central tooth: 1-L-L, Ut left lateml: i-L-L. ith Icjl
lateral: U-L-L, Uth left lateral: 1-L-M. 1st left marginal: 8-
L-M. Sth left marginal. B: A jatr o/'Catinella parallela n. sp.

68 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

water while Sagittaria latifolia Willd. and Spar-
tina sp. grow in very wet ground. Oxyloma
salleana (Pfeiffer) lives on the cattails and on
dead vegetation floating on the water. Catinella
parallela lives near the water's edge on the base
of cattails, on the matting of dead vegetation and
on bare spots on the wet ground shaded by saw-
grass and leaf litter.

Locality 5, Field No. D.S.F. 467; ten miles N
Vincenes, Knox County, Indiana, roadside ditch
along U.S. Hwy. 41. Although at the time this
site was visited the water was becoming polluted,
TjfjAa sp. was growing in the ditch and Catinella
parallela was still living there.

Lncalitii 6. Field No. D.S.F. 269; eastern bank
of the Illinois River at New Hardin, Greene
County, Illinois. On June 11, 1964, the ground
was muddy from recent rains. The bank sup-
ported a thicket of Salix sp. (willows). Oxyloma
salleana (Pfeiffer) lived on the muddy bank.
Catinella parallela was found creeping on the wet
ground, on surfaces of wet boards and other
debris on the ground along the eastern edge of
the flood plain away from the shore of the river.
Since then, as a result of severe storms and
flooding, the entire flood plain is littered with
logs, branches and other debris. The habitats of
the two succineid species are destroyed, at least
temporarily.

Locality 7, Field No. D.S.F. 445; eight-tenths
mile S Nutwood, or 2.4 miles S from the junction
of Illinois Hwy. 100 and Illinois Hwy. 16, Jersey
County, Illinois, on the west side of Illinois Hwy.
100. The habitat is a poorly drained slough. The
bottom of the slough consists of fine, tan sand,
and coarse, sandy reddish-tan loess from the
deposit immediately to the east. The slough sup-
ports growths of Typha sp., Eleocharis sp.,
Polygoneum ineum Muhl and RMis radicans L.
Several small clumps of Popuhis deltoides Marsh
and a thicket of Comus drummondi C. A. Meyer
are located within the slough. On June 1, 1975, a
large population of Oxyloma salleana (Pfeiffer)
lived on Ti/i)ha sp. and on the wet ground at the
base of the cattails. A well-establi.shed population
of Catinella parallela lived on the eastern edge of
the slough on wet, but not swampy, ground where
the vegetation was less dense. One June 11, 1977,

due to an abnormally low amount of rainfall dur-
ing the spring months, there was no water in the
slough but the ground was still damp. 0. salleana
was feeding on cattails and spike rish. However,
a four-hour search netted only one individual of
r. parallela. This might indicate that C parallela
is more readily affected by adverse conditions
than is (). salleana.

Locality 8, Field No. D.S.F. 187; Pere Mar-
quette State Park, Jersey County, Illinois, west
side of Illinois Hwy. 100. The site is the east
shore of a lake formed by a bow of the Illinois
River. On June 15, 1954, Oxyloma salleana (Pfeif-
fer) and Catinella parallela were abundant on the
wet ground and on wet boards lying on the bank.
I have visited this site several times but have not
found C parallela since 1954, although 0.
salleana is still well-established.

Diagnostic Features. Shell: the elongate-ovate
shell is comprised of 3''4 to 3' : tumid whorls. The
height of the ovate aperture exceeds six-tenths of
the height of the shell. Two examples of the latter
are: (a) The height of the shell of the holotype is
10.0 mm and its aperture 6.7 mm in height ; height
of aperture / height of shell is .67. (b) The height of
the largest shell of the series studied is 15.2 mm
and its aperture 9.6 mm in height ; height of aper-
ture / height of shell is .632. The amber-colored
columella forms the inner border of the peristome.
A thin callus is discernible on the ultimate whorl
above the aperture.

Penis and Penial Appendage: the base of the
penial appendage equals almost half the length of
the penis. The expanded appendage is positioned
parallel to the penis. The vertical dimension of
the appendage is almost twice the width of the
body of the penis. The penial retractor muscle
inserts mainly onto the base of the i^enial appen-
dage and by means of lesser fibers onto the penis
andtheepiphallus.

The specific name parallela refers to the ex-
panded penial appendage being parallel to the
penis instead of right angle to the penis as is
characteristic of other species in the genus

Catinella.

Spermatheca: the globular spermatheca is con-
nected to the vagina by a stout duct which en-
larges as it approaches and enters the vagina.

Vol. 9:1 (2-3)

April 2:1 1979

THP] NAUTILUS 69

Comparative Remarks: ('(it'meUn piimUcla
probably more nearly resembles C. texana
Hubricht than any other described species. The
differences include: (a) Shell dimensions and
ratios of dimensions. (1) The aperture of C.
parallela is larger in proportion to the height of
the shell than it is in C. texana. (2) The largest
known shell of C. parallela is 15.2 mm in height,
(b) The penial appendage of C. parallela is
parallel to the penis whereas in C. texana the
penial appendage is vertical in position, i.e. at
right angle to the penis, (c) The penial retractor
muscle of C. parallela inserts mainly onto the
base of the penial appendage; lesser fibers insert
onto the penis and onto the epiphallus. The peni-
al retractor muscle of C. texana is "connected to
the side of the penis near the middle" (Hubricht,
1961, p. 61). (e) The spermathecal duct of C.
parallela is stout, of C. texana slender, (f) The
seminal vesicle of C. parallela is pigmented but
not as darkly as described of C. texana as being
"strongly pigmented, almost black" (ibid).

ACKNOWLEDGMENTS

National Science Foundation Grants-in-Aid
No's. NSF G18000 and NSF GB2715 provided
laboratory equipment and supported, in part, the
field studies. Dr. A. Byron Leonard read the
manuscript and offered helpful suggestions.

LITERATURE CITED

Franzen, Dorothea S. 1959. Anatomy of Sitccinea ovdis Say.

Pmc. Mai. Soc. Lmidon 33(5, Nov.) : 193-199, tables 1-2, figs.

1-7.
. 1963. Variations in the Anatomy of the Succineid

Gastropod Ozyloma retiisa. The Nautilvs 76(3): 82-95. tables

1-2, figs. 1-4.

1966. Anatomy of the Succineid Gastropod Ox-

yloma salleana (Pfeiffer) The Nautilus 80(2): 59-69, tables
1-2, figs. 1-3,

1969. Structural Characteristics of Succineid

Gastropod Oxyloma sanibelensis. The Nautiliix 82(3): 77-83,
tables 1-3, figs. 1-2.

. 1971. Anatomy and Geographic Distribution of

the Succineid Gastropod Suvcinea vaginajcontorta Lee. The
Nautilus 84(4): 131-142, tables 1-2, figs. 1-3.

. 1973. Oxylnma deprimida, A New Species of Suc-

cineidae (Pulmonata). The Nautilvs 87(3): 66-71. tables 1-3,
figs. 1-a

Hubricht, Leslie. 1961. Eight New Species of Land Snails from
the Southern United States. The Nautilus 75(1): 26-33, pi. 4,
fig. 1; 75(2): 60-61, fig. 2.

Patters(3n, C. M. 1971. Taxonomic Studies of the Land Snail
Family Succineidae. Malacological Review 4(2): 131-202.
tables 1-2, figs. 1-140.

Pilsbry. Henry A. 1948. Land Mollusca of North America
(North of Mexico). Acad. Nat. Sci. Philadelphia Monograph
3, vol. 2. pt. 2: pp.i-xlvii -I- 521-1113, .585 figs.

Quick, H. E. 1933. The Anatomy of British Succineae. Pmc.
Mai. Soc. London 20(6): 295-318, pis. 23-25, tables 1-5, figs.
1-18.

REDISCOVERY OF SOME PLEUROCERIDS (GASTROPODA)
NEAR MUSCLE SHOALS, TENNESSEE RIVER, ALABAMA

Billy G. Isom', Sally D. Dennis^ and Charles Gooch'

Lithasia verrucosa (Rafinesque, 1820), Lithasia
geniculata salehrosa (Conrad, 1834), and
Pleurocera alveare (Conrad, 1854) were
rediscovered in May 1977 at Muscle Shoals, Ala-
bama, below Wilson and Wheeler Dams on the
Tennessee River.

The last records of L. g. salehrosa from the

'Tennessee Valley Authority, E&D Building, Muscle Shoals.
Alabama 35660

'Tennessee Valley Authority, Forestry Building, Norris, Ten-
nessee 37828

Tennessee River, of which the authors are aware,
was reported by Goodrich (1934). Davis (1974) and
Stein (1976) presumed that "pure salehrosa is
probably extinct." However, their statements
were apparently based on the literature and on
material collected from the Duck River, but
neither attempted to sample the original Ten-
nessee River habitat of this species. L. g.
salehrosa was found in the tailwater of Wilson
Dam, the area from which Conrad collected the
type specimens.

70 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

Ij. veri-iicond was found in the Tennessee River
at Florence, Alabama, along the south shore be-
low U.S. Highway 72 bridge. It undoubtedly oc-
curs elsewhere in the river, but its total distribu-
tion is not now known. Historically, this species
was found in large rivers and large tributaries
such as the Ohio, Tennessee, Wabash; Black, and
Spring Rivers in Arkansas (Grwdrich, 1940); Cy-
press and Flint River tributaries of the Tennessee
River in Alabama; the Nolichucky River in Ten-
nessee (Davis, 1974); and other streams. Sinclair
(1969) indicated that L. verrucosa was limited to
areas below Kentucky and Pickwick Dams in the
Tennessee River.

P. alveare was found just below Wheeler Dam
on limestone bluff outcrops, generally in water to
three meters deep. Sinclair (1969) assumed this
species was killed off by impoundment, while
Stein (1976) indicated that status of "other"
populations was unknown. Historically this spe-
cies was limited, in the Tennessee River, to the
shoals near Florence, Alabama, and to a number
of local tributaries, particularly Cypress Creek
(Goodrich. 1934a, 1934b, 1940, 1941).

These snails were collected by scuba divers.
Collection by scuba divers is a very effective
technique for sampling rock-y substrates, which

are difficult to sample effectively with conven-
tional grab samplers. We expect to devehjp addi-
tional data on these species through the coming
months. We particularly wish to thank W. Jef-
frey Pardue and Jimmy G. Walden for their par-
ticipation in this project.

LITERATURE CITED

Davis, George M.. 1974. Report on the Rare and Endangered
Status of a Selected Number of Freshwater Gastropoda
from Southeastern U.S.A. For the U. S. Department of the
Interior, Fish and Wildlife Service, Contract No.
M018-f)()(l8-766. pp. 32-a5.

Goodrich, ("alvin, 1934a. Studies of the Gastropcxi Famil.v
Pleuroceridae-I. C)rr. Paper.'^. Museum of Zoology, University
of Michigan. No. 286: 17 pages. 1 plate.

. 1934b. Study of the Gastropod Family

Pleuroceridae-III. Occ. Papers. Museum of Zoology. Univer-
sity of Michigan. No. .300: 11 pages.

. 1940. The Pleuroceridae of the Ohio River

Drainage System. Occ. Papers. Museum of Zoology. Univer-
sity of Michigan. No. 417: 21 pages.

. 1941. Studies of the GastroiX)d Family

Pleuroceridae-VIII. Or. Papers, Museum of Zoology,
l.'niversity of Michigan. No. 4-17: 13 pages.

Sinclair. Ralph M.. 1969. The Pleunx^erid Fauna of the Ten-
nessee River Gastropoda: Prosobranchia. American
Malacningical Union, Annual Report: pp. 4.5-47.

Stein. Carol B., 1976. Gastropods. In: Endangered and
Threatened Plants and Animals of Alabama. Bull. Alalmmn
Miiseuni <if Natural Hittury. No. 2, pp. 21-.52.

A NEW VERTIGO (PULMONATA: PUPILLIDAE)
FROM THE OZARKIAN UPLIFT

Amy Shrader Van Devender

Mollusk Division, Museum of Zoology

University of Michigan

Ann Arbor, Michigan 48109

ABSTRACT

A new s-pecien of pupillid. Vertigo meramecensis, (.s described from Cniwford
County. Mii^xonri. It is most similar to Vertigo gouldi and in the sixth Recent
Vertigo reported from the Noiihern Ozark Plateau. The type locality along Huz-
zah Creek would be flooded periodically if the proposed dam on the Meramex:
River is completed.

On 12 June 1976 five other people and I were
exploring some wooded limestone bluffs in Craw-
ford County, Missouri. The site was south of Huz-

zjih Creek, a few miles south of where it joins
Courtois Creek which flows into the Meramec
River nearby. This area lies at the northern edge

Vol. 93 (2-3)

April 23, 1979

THE NAUTILI'S 71

of the Ozarkian Uplift (or Ozark Mountains), a
large plateau covering parts of four states. A
representative collection of land snails, including
a new species of VeHigu. was made just after
dark. The evening was warm and muggy; and
snails were rommon, actively browsing in the
plant cover on the bluff face. The tiny Vetiiya.
found alive, was first seen by Meg LaVal, who
was using a headlamp to search the mosses and
lichens on the limestone bluff.

Malacologists have long found the Ozarks to
contain an interesting and diverse snail fauna.
As the literature survey in Reeder and Miles
(1976) points out, though, collecting has been
spotty with only a few areas at all well known. It
is not surprising to note that since Pilsbrj' (1948),
only Hubricht (1964, 1972) mentions any Voiiyo
from southern Missouri.

Vertigo meramecensis, n. sp.

Figs. la,b: 3b

Description of Holotype: Shell (Fig. la) oblong,
tapering with five well-rounded whorls, per-
forate: 1.86 mm long and 1.15 mm wide, H/D =
1.82. Shell surface (especially middle whorls)
strongly, but irregularly striate with embiyonic
whorls smooth. Shell translucent, chestnut in
color; lip darker than shell and reflexed with on-
ly a slight constriction. Penultimate whorl bears
a crest (Fig. lb) which separates the lip from a
broad depression external to the palatal teeth
and extends to just above the middle of the
whorl. Aperture (Fig. 3b) one third shell length,
angular, slightly higher than wide. Tooth formula
1-2-2; subcolumellar weakly developed; all teeth,
white, situated near the lip edge with lower
palatal slightly more recessed than the upper;
parietal in line with the lower palatal.

Paratypes: Sixteen specimens. Adults (n = 10)
have a reflexed lip and range in length from 1.72
mm to 2.01 mm (x = 1.83 ± 0.01) and in width
from 1.05 mm to 1.20 mm (x = 1.10 ± 0.01). Half
of the adults lack a subcolumellar lamella
altogether. The lower palatal is more recessed
from the lip edge and longer than the upper
palatal. The lower palatal is variable in length;
three specimens have the long, slightly cun-ed
lower palatal shown in Fig. 3b while the fold is
knob-like in the holot>i)e. This character may de-
pend on the maturity of the animals.

FKl. la. Vertigo meramecensis Van Devender, new species.
Hnti,t>fi>e lUMMZ 2i7l>iO). 1.86 mm. Crawford Co.. Missouri.
b, Paratiipe (L'MMZ2i76il). 1.87mm.

Etymology: From the Meramec River drainage
where the species was collected and the proposed
Meramec Dam which would periodically flood the
tyije locality {pers. comm. Dr. R. K. LaVal,
Missouri Department of Conservation ).

Types: Holot^^pe, Museum of Zoology, Univer-
sity of Michigan 247640; 13 paratypes in the
Museum of Zoology, University of Michigan
247641; 2 in the Field Museum of Natural His-
tory and the collection of the author.

Type Locality: Wooded limestone bluffs above
Huzzah Creek, 13.8 km E of Steelville, Crawford
Countv, Missouri (USGS Berrvman 15' NWSW-
SWNWNE Sec 24, T38N. R3W).

Discussion: Vertigo memmecenfns belongs in
the genus VeHigo because of its small size, red-
brown color, and moderately well-developed teeth.
Pilsbry (1948: 943-1000) discussed the shell char-
acters of Vertigo and placed most species in the
subgenus Vertigo (sensu stricto). He divided the
subgenus into seven species groups whose compo-
nent species var>' so widely and overlap so great-
ly that Pilsbry himself was unable to construct a
key to them. The new species shares some charac-
ters with at least two species groups, the Vertigo
modesta group and the Vertigo gouldi group, but
seems closest to the Vertigo gouldi group. Pilsbry
(1948) and Hubricht (1964, 1972) report eight spe-
cies of Ve^iigo from the northern Ozarks. Of
these, two are placed in the Vertigo gnuldi
species group - V. gouldi gouldi and V. hubrichti.
which was described as a subspecies of V. gouldi
and is known only from fossil material.

72 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

FI(_;. :ia, N'ertigo ijjuldi gduldi (Hitmen). (i'MMZ mil)- 1.9
ruin. CuinbcrUuid Co.. Maine, b. Vertigo hubrichti Pikhry.
Paratmw (ANSiP m)S(>2). 2.0.J mm. St. Lmm O,.. Mi^simri.

Vertigo meramecensis resembles the species
and subspecies in the V. gouldi group in that it
has a distinctly striate shell, averages less than 2
mm long and displays about 5 moderately well-
developed, white teeth. Unlike the majority of
members in the species group, it lacks an angular
lamella and its parietal lamella is directly in line
with the lower palatal fold.

Comparisons with the Ozarkian members of the
V. gouldi group are in order. Vertigo meramecen-
nis at least superficially resembles the illustra-
tion in Pilsbry (1948:973, Fig. 521) of the fossil V.
hubrichti. E.xjimination of four paratypes of Ver-
tigo gouldi hubrichti (ANSP 160362, Fig. 2b),
however, shows that V. mprnmprrnsin has a
smaller, more tapered and more distinctly striate
shell. While the lower palatal fold of V. hubrichti
(Fig. 3a) is situated very deeply in the mouth of
the shell like V. gouldi pamdoxa and V.

nijliinderi, the palatals of V. mpramecentfis (Fig.
3h) are close to the lip edge with lower fold only
slightly more recessed than the upper. The parie-
tal of V. hubrichti points toward the upper
rather than the lower palatal fold. The sculpture
of Vertigo meramecensis is heavier and more ir-
regular than in Vertigo gouldi gouldi (Fig. 2a)
and V. meramecensis with smaller teeth has a
more open aperture than V. gouldi. The parietal
tooth especially is less massive and straighter
than in V. gouldi (Fig. 3c) whose parietal points
between its palatal folds.

Of the Vertigo species known from outside the
Ozarks, V. meramecensis most closely resembles
the illustrations of Vertigo gouldi cristata from
Eastern Canada (Pilsbry 1948:967-4,5). Compar-
isons with a series of shells from Southern On-
tario (UMMZ 180213) show that V. meramecenda
has heavier teeth, a more nearly square aperture,
a darker (redder) color and a weaker crest than
cristata. Vertigo meramecensis sometimes has the
subcolumellar (basal) lamella that never occurs in
V. g. cristota.

Land snails collected with Vertigo meramecen-
sis include Anguispira alternata (1), Glphi/alinia
iudentata (2), Mesodon thyroidus (1). Mcsodou
zaletiis (18), Triodopsis fosteri (39), and Triodop-
•s/.s- albolabns (5).

ACKNOWLEDGMENTS

The scanning electron micrographs were taken
by the author with the help and advice from the
staff of the SEM Laboratory, Department of
Metallurgy and Dr. Alex Tompa, Museum of
Zoology, University of Michigan. Dr. Tompa and

FIG. :?a, Verlifci) hubrichti PilKhrii. Pmatinx' IA.\'SP lno.UiJ).
Enlanjnuent of aperture, r. l.^.i X. b. Vertigo meramecensis
Win I )e re litter, neie xperiex. Parat iflte fl'MMZ i.',7l>ill. Aper-

ture irith siiheiiliiiKellar ItiiiieUiu e. lJ,.'i X. c, Vertigo gouldi
gouldi (Binneij) (i'MMZ iJ.iJlJ. Enlargement of aperture, e.
l.',r, X.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 73

Dr. J. B. Burch (l)oth UMMZ) and Dr. Georpe M.
Davis (ANSP) kindly let me e.xamine and take
micrographs of material in their care. I want to
thank Mep and Richard LaVal and Richard W.
Fullington who read early drafts of the manu-
script. Special thanks to R. W. Van Devender,
Leslie Hubricht. and J. B. Burch who each in his
ow-n way encouraged me to wi-ite this paper.

LITERATURE CITED

Hubricht. Leslie. 1964. Some Plei.sti>cene Land Snail Records

from Missouri and Illinois. S^fWi-iV/zja. (13): 7-17.
1972. Land Snail Reairds from Missouri.

Sterkiana, (45): 34-^5.
Pilsbn', Henry A. 1948. Land Mollusca of North America

(North of Mexico). Mimdyniph Aiwl. \ul. Sri. Philadelphia

3. 2(2): 868-1018.
Reeder. Richard L. and Charles D. Miles. 1976. Land Snails

from Northern Missouri. SferWano, (61): 15-18.

OBSERVATIONS ON THE FINGERNAIL CLAM, MUSCULIUM PARTUMEIUM

(PISIDIIDAE), AND ITS ASSOCIATION WITH THE INTRODUCED

ASIATIC CLAM, CORBICULA FLUMINEA

Alton C. Boozer and P. E. Mirkes

Department of Environmental Science, School of Public Health

Belle W. Baruch Institute for Marine Biologv' and

Coastal Research, and The Department of Biology

University of South Carolina

Columbia, South Carolina 29208

ABSTRACT
In the cooling water system at the ERDA Savannah River Plant, the introduced
Asiatic clam, Corbicula fluminea, is inhabiting the floor of the sedimentation basin
and is contributing to fouling problems. A second species of bivalves, the fing email
clam, Musculium partumeium, permanently inhabits the wall of the basin by
means of a byssal-like attachment. The possibility of spatial competition between
these two bivalves is discussed with emphasis on ok^ervations on reproduction. It
is concluded that because of physiological adaptability M. partumeium can coexist
with Corbicula.

The Asiatic clam, Corbicula fluminea (Muller)',
was first reported in the United States in 1938 in
the Columbia River of Washington State (Ingram,
1959). By 1963, Corbicula had spread into the
Mississippi and Gulf of Mexico Drainage, as evi-
denced by the Ohio River and Tennessee River
discoveries (Sinclair and Ingram, 1961; Keup et
ai. 1963). Sinclair (1971) excluded the Atlantic
Slope region from the known range of Corbicula
until Sickel (1973) reported that the exotic clam

' This species is called Corbicula manilensis Philippi by many
workers, but we prefer to use the earlier name, fluminea
(Muller).

had probably been introduced to the Altamaha
River of the Southern Atlantic Slope region of
Georgia in 1968 or 1969. Fuller and Powell (1973)
reported Corbieida in the Savannah River and
Delaware River. Diaz (1974) found Corbicula in
the James River, Virginia, and more recently,
Rodgers et al., (1977) reported Corbicula in the
New River, Virginia.

During the course of its range extension, Cor-
bicula has caused a dramatic increase in water
use interference. Ingram (1959) reported Cor-
bicula fouling problems in California, as did

74 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

Sinclair (1964) in Tennessee. After the introduc-
tion of Corbicula in the Savannah River, a
similar fouling problem developed at the United
States Energy Research and Development Ad-
ministration's (ERDA) Savannah River Plant.
Openings in a plate from a non-reactor cooling
process were clogged with adult Corbicula shells,
thus restricting water flow (Tilly, 1976; pergonal
communication).

Fouling caused by the Corbicula invasion is not
the only concern of investigators. The possibility
of a drastic impact on other bivalves has been of
great concern to biologists. Sickel (1973) observed
that where Corbicula were most dense in the
Altamaha River, Georgia, there were no union ids,
although the habitat appeared suitable. Gardner
et al. (1976) determined that the invasion of Cor-
bicula in the Altamaha River had been ac-
companied by a drastic decline in the populations
of other bivalves (Pisidiidae and some Union-
idae).

During Ccrrbicula fouling studies at the ERDA
Savannah River Plant, a sedimentation basin of a
water treatment plant was found to contain two
dominant species of bivalves. One of the species
was Corbicula fluminea (Miiller), the other
species was Musculium partumeium (Say).
Earlier studies had shown that the Corbicula in-
vasion had had an impact upon other bivalves.
This study deals with the association between M.
partumeium and Corbicula.

Description of Study Area

The study area is located within the designated
4(X) area of the U.S. Energy Research and
Development Administration's (ERDA) Savannah
River Plant. A water intake structure is located
on the Savannah River from which water is
pumped through a closed pipe to the 400 area
water treatment plant. Water is first received at
the plant in a sedimentation basin. From this
point, a portion of the water receives additional
treatment for extensive use in the 400 area. The
larger portion of incoming water receives little
treatment and is used as cooling water in a non-
reactor cooling process. It was in this cooling pro-
cess that Corbicula fouling was first observed. A
subsequent investigation lead to the discovery

that the sedimentation basin had become a per-
manent habitat for freshwater clam populations
of both Corbicula and M. partumeium.

The sedimentation basin consists of concrete
bottom and walls. The bottom of the basin is
covered with an extensive amount of mud, silt,
and sand from the settling process. Due to the
sediment buildup, the depth of the basin ranges
from 4 to 8 feet with an average depth of 5 feet.
An excellent substrate has developed for macro-
invertebrates, since the basin has not been
cleaned in at least eight years. Water remains at
a fixed level in the basin throughout the year,
thus allowing some organisms to inhabit the con-
crete walls of the basin. It was decided that since
fouling problems had originated in the sedimen-
tation basin, specimens would be collected from
that area.

Additional sampling was attempted in the
Savannah River adjacent to the Savannah River
Plant property. Water fluctuation resulting from
the Clark Hill Reservoir Hydroelectric Plant
made river access difficult, and therefore sam-
pling was abandoned.

Materials and Methods

Qualitative samples were taken monthly from
the 400 area sedimentation basin from January,
1976, through July, 1976, including a semi-monthly
sample in June, 1976. Samples of Corbicula were
obtained by scooping the clams from the bottom of
the basin with a commercial clam shovel. Samples
were collected from the walls of the basin with a
plankton net (25 micron). The net was lowered to
the substrate-water interface beside the wall and
then dravTO up the side of the wall toward the
water surface. An effort was made to take approx-
imately the same amount of material each time
since careful quantitative measurement was not
possible. Samples were placed in styrofoam coolers
containing aerated river water and returned to the
laboratory for careful sorting so that the young
would not be overlooked.

Numerous gross dissections were made under a
binocular scope and many observations were made
upon young and transparent specimens under a
compound microscope. A sub-sample of 30 of the
fingernail clams, M. partumeium. was taken from
each of the April, May and June collections for

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 75

determination of approximate brood sizes for iden-
tification purposes. The left and right inner
demibranches of the gills were excised from each
parent, and enclosed larvae were counted and
measured for length with the aid of an ocular
micrometer. Unfortunately, because of the nature
of the collecting method employed, it was impossi-
ble to determine whether some or all of the extra-
marsupial larvae had been prematurely born or
aborted, with the result that the number of in-
cubating larvae found upon dissection may have
been misleadingly low. Determinations were made
to approximate size classes for developmental
stages of M partumeium larvae.

During August, 1976 the study was abruptly
halted when collections indicated that a complete
kill of both species of clams had occurred. Post-
chlorination facilities at the water treatment plant
had become inoperable, leading to emergency pre-
chlorination of water prior to its entry in the
sedimentation basin. Malfunction of the pre-
chlorination equipment allowed excessive levels of
chlorine to enter the basin for a period of several
days, thus resulting in the kill.

A collection of Corbicula was made in the Savan-
nah River on August 26, 1976 to check for gravidity.
An attempt was made to collect M. partumeium.
but none were found. Since Corbicula in the Savan-
nah River were incubating young, qualitative and
quantitative samples were collected from the
sedimentation basin in January and April, 1977, to
determine if repopulation was occurring through
recruitment from the Savannah River. The quali-
tative samples were collected from the wall of the
basin as described previously. Quantitative
samples of the bottom material were made with a
standard Ekman dredge. All of these collections
were preserved immediately in 70 percent ethanol
and returned to the laboratory. Clams were iden-
tified and counted, and some sf)ecimens were mea-
sured for length (anterior to posterior) with an
ocular micrometer.

Results and Discussion

Taxonomy

The superfamily Corbiculacea Gray, 1847 is
represented in North America by 37 species of the
family Pisidiidae Gray, 1857 (formerly Sphaeri-
idae, Jeffreys, 1862), and by one introduced species

(Corbicula fluminea) of the cosmopolitan family
{x)rbiculidae (Burch, 1975). The Pisidiidae contain
the five genera Sphaerium, Musculium, Pmdium,
Byssanodonta, and Eupera. Baker (1927) divided
the family into two subfamilies, based on the char-
acters of the siphons. Heard (1965) later found
enough differences to warrant three separate sub-
families, distinguishable on the basis of the nature
of their siphonal arrangement and development of
their embryos. The subfamilies are Sphaeninae,
containing the genera Sphaerium and Musculium.;
Pisidiinae. containing the genus Pisidium; and
Euperinae. containing the genus Eupera (Burch,
1975).

In North America there are eight species of
Sphaerium and four species of Musculium (Burch,
1975). One of the characteristics used to justify the
validity of Musculium as a genus was the presence
of a calyculus or "cap" at the umbone. Sterki (1909)
found, however, that in most species of Musculium.
specimens are found with slightly or noncalyculate
beaks and that calyculate beaks are found occa-
sionally in specimens of Pisidium and Sphaerium.
Herrington (1962) suggested that calyculi have lit-
tle taxonomic value because he, too, witnessed their
occurrence in groups other than Musculium. He
concluded Musculium to be a synonym, or at most a
subgenus, of Sphaerium because of the lack of
significant diagnostic shell characteristics to dis-
tinguish the two. When Gale (1972) determined
that arrested growth caused the formation of a
calyculus, he further questioned the taxonomic im-
portance of this character. Studies on calyculate
and uncalyculate forms of Mu.sculium securis
(Prime) by Mackie and Qadri (1974) indicated that
calyculism is a predictable feature, and that the
so-called "caps" of Sphaerium species are probably
"pseudocalyculae". True calyculae are separated
from adult valves by a sulcus, but "pseudocaly-
culae" are separated by an annulus. The calyculate
character is of significance in identifying different
generations in Musculium populations.

More recently. Heard (1977) has indicated that
Musculium is a valid genus on the basis of several
life history aspects. He concluded that: (1) propor-
tionately more species of Musculium can inhabit
temporary ponds than species of Sphaerium; (2) the
extra-marsupial larvae of all knovra species lack

76 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

eggs and sperm, which are found in the larvae in
most species of Sphaerium; (3) all known species of
this group show a higher fecundity, in terms of to-
tal numbers of young produced, than do most spe-
cies of Sphaerium: (4) its species in general appear
to have a shorter life cycle (30-70 days) than do
Sphaerium spp. (4-8 months); (5) individuals of this
group may have a shorter life span than do those of
most species of Sphaerium: and (6) the two siphons
in Musculium are fused together in their basal
halves only, whereas, those in Sphaerium are fused
together for their entire length. In addition, the
shelled larvae in the gills of all Musculium species
and Sphaerium comeum and Sphaerium occiden-
tale are anchored by a byssal thread to a common
stalk. Heard (1977) further noted that S comeum
and S. occidentale occupy a comparatively in-
termediate position between the two genera, shar-
ing a number of features of both groups (see Table
1). These two species have traditionally been placed
in Sphaerium, either because of their lack of
calyculated beaks or because of the degree of siphon
fusion.

From observations on anatomy, e.xpected
habitat, and life histor\' of the pisidiids. and up<in
comparison with features presented in Table 1 and
the preceding discussion, the clam inhabiting the
sedimentation basin was determined to be of the
genus Musadium. Although characters of soft
anatomy are used in taxonomy of the Corbiculacea,
especially in the classification to the generic
level, all taxa can be identified by characters of
the shells, and such shell characteristics are par-
ticularly important in distinguishing the species
(Burch, 1975). Considering characters of the shell,
habitat, and range, the pisidiid in this study was
identified as Musculium partumeium (Say). A
description of the key shell characteristics follows:
Hinge of smooth lateral teeth ; beaks of shell
located centrally or anterior of center; shell with
two cardinal teeth in one valve, and one in the
opposing valve; shell sculptured with fine striae;
adult shell small, less than 8 mm in length;
posterior end nearly at right angles to the dorsal
margin ; anterior ventral margin of shell slopes
upward, but only slightly; surface glossy (Burch,
1975).

TABLE 1. Comparison o/Sphaerium corneum. Sphiierium ix-ddentale. "?/ipr Sphaerium. and Masculium (Heard. 1S7T).

Feature

S. corneum

Siphon fusion

entire

+

partial

Standing water

permanent

+

temporary

Mature gametes in extra

marsupial larvae

+

Functional byssus in

late larvae

+

Number of F/^ per sac

few

+

many

Size of newborn

small

large

+

S. corneum S. occidentale Sphaerium

Musculium

F, - a collective designation given fur all incubatinp young regardless of stage of development.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 77

M. partumeium is distributed throughout the
United States and in southern Canada from New
Brunswick to Saskatchewan (Herrington, 1962). Its
habitat includes mud bottoms in small lakes,
ponds, and swamps, and lotic situations. Clarke
(1973) also found its habitat to include muddy parts
of large lakes in the Canadian Interior Basin, as
well as vernal ponds. Baker (1928) found it in black
mud in shallow water of stable and temporary
ponds.

Little will be included here concerning the tax-
onomy of Corhicula fluminea in this study. Sinclair
and Isom (1963) have documented this subject fully
in an earlier report. Corbicula from the 400 area
sedimentation basin and the Savannah River was
easily identified by the presence of three cardinal
teeth per valve, the serrated lateral teeth, and the
ribbed appearance of the shell (Sinclair and Isom,
1963). Corbicula manilensis Philippi is considered
by us to be a synonym.

Attachment inM. partumeium (Say).

Identifications performed on the qualitative
samples collected from the wall of the 400 area
basin during the January through June 1976 collec-
tions, revealed that a population of the fingernail
clam, M. partum£ium, was inhabiting the wall of
the sedimentation basin. From on-site visual ex-
amination of the samples, it appeared that the
clams were actually attached to the wall and not
burrowed under the thin layer of oligochaetes on
the wall. Live specimens, after being sorted from
oligochaetes and debris and being placed in glass
aquaria in the laboratory, could readily climb the
vertical walls of the container and attach to the
glass. The foot of the clam is used in climbing but
once the clam is on the vertical surface, threadlike
filaments allow the clam's valves to remain closed
while the clam is freely suspended from the side of
the glass. Shell lengths of the M. partumeium en-
countered on the wall and observed in the lab-
oratory ranged from 1.2 mm to 6.2 mm.

In describing the subfamily Sphaeriinae, Monk
(1928) noted that the foot is anchored by means of
an expansion of the anterior tip and ventral side.
Adhesion is facilitated by a mucus secretion from
the mucus glands of the foot. He noted that the
mucus secretion is an important means of anchor-
ing the foot, and that young specimens could climb

vertical surfaces by this aid alone. Monk (1928) ad-
ded that the byssal gland is vestigial in Sphaeri-
inae. The gland is much larger in the embryo, but
the duct that supplies the gland is already occluded
in embryos 1 mm or less in length. In contrast,
Baker (1928) stated that while the adults usually
bury themselves in the bottom, the young may be
very active, crawling over plants and even suspend-
ing themselves from plants by byssal threads, thus
suggesting a functional byssal gland.

When Heard (1965) divided the Pisidiidae into
three subfamilies, he stated that Euperinae
possess a functional byssal gland, whereas Sphae-
riinae (Sphaerium and MusculiumJ and Pisidii-
nac did not. Byssanodonta. another pisidiid, lim-
ited in distribution to South America, is known
to have a functional byssal gland. More recently,
Heard (1977) has reported that a functional
larval byssus occurs in all North American
species of Miisculium, Sphaerium ocddentale
(Prime), and Sphaerium comeum (Linnaeus). The
byssus is evident in the shelled larvae (prodisso-
conch and extra-marsupial development stages)
and is believed to function in the prevention of
precocious birth (abortion) until the larval gonads
sexually mature (Heard, 1977). Mackie et. al,
(1974a) described the structure of the larval
byssus of Musculium securis (Prime) as consisting
of a byssal stalk that originates in the foot of the
prodissoconch larvae and a byssal bulb that in-
serts on the descending lamella of the inner gill
of the parent. In this study, dissection of gills of
M. partumeium collected from the sedimentation
basin revealed the presence of the byssal stalk
and byssal bulb on prodissoconch and some extra-
marsupial larvae.

In reviewing the significance of the byssus in
bivalves, Yonge (1962) stated that in cases where
the byssus is retained for permanent attachment of
the adult, it also functions in early life when the
foot is still active as an organ of temporary attach-
ment. By this means, the young bivalve climbs ver-
tical surfaces. He added that, in general, wherever
a functional byssal apparatus is present it is ob-
viously related to a change in habit from infaunal
to epifaunal life. Yonge (1962) concluded that the
presence of a byssal apparatus in the adult

78 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

represents the persistence of a post-larval organ.
i.e., that the animals possessing it are in this
respect neotenous.

The functional larval byssus, the epifaunal hab-
itat of the clams on the basin wall as well as the
record of vertical attachment, all suggest a func-
tional byssus in adult M. partumeium. Whether the
byssal-like attachment by thread derives from a
functional byssus or by mucus secretions from the
foot is uncertain. However. M. partumeium does
have a method of attachment allowing it to inhabit
the wall of a basin throughout its lifetime.

Notes on Reproductum.

During the course of this study, some observa-
tions on reproduction in M. partumeium were
made, mainly for the purpose of identification of
the species but also to note any major changes in
reproductive habit associated with byssal-like at-
tachment to the wall of the sedimentation basin.
Observations on reproduction in Corbicula were
included.

Like all Sphaeriinae, M. partumeium is
monoecious and ovoviviparous; it is self-fertil-
izing internally (Thomas, 1959). Fertilized eggs
are retained and incubated within the body of
the parent, and development of the embryos takes
place in the marsupial or brood sacs formed by
the inner (anterior) gills. Gilmore (1917) and
Mackie et at.. (1974b) have described the struc-
ture and development of such brood sacs in cer-
tain species of Sphaeriinae. In his division of the
Pisidiidae into 3 subfamilies, Heard (1965) used
as a distinguishing characteristic the fact that in
Sphaeriinae the embryos develop in several thin-
walled longitudinal sacs in each anterior gill,
each sac containing one or more embryos.

Observations on samples collected from the sed-
imentation basin during January through July,
1976, and January and April, 1977, revealed that
some M. partumeium were brooding extra -
marsupial larvae in the gills during each collec-
tion. A peak in number of young ranging in size
from 1.3-2.0 mm was evident in the June 10, 1976
sample and the January, 1976 and 1977 samples.
All clams collected were not size classed, but the
January and June peaks in number of young
were visually evident during field collection and
laboratory examination.

Gilmore (1917) and Foster (1932) reported that
reproduction in Sphaerium goes on throughout
the year, with a preponderance of young at cer-
tain times of the year. Mackie et al., (1976a)
found that births occurred throughout the year in
a population of M. securis collected from a per-
manent aquatic habitat in Canada. They con-
cluded from size classes dominating the summer
collections and from newborn dominating the
winter population that birth periods occurred in
early summer and late summer-early autumn in
the permanent habitat. Thomas (1959, 1963, 1965)
studied a population of M. partumeium in a tem-
porary pond and found that the production of the
first young was seen in June when the pond had
filled in March. Standing water disappeared from
the pond in late June, leaving primarily young
individuals which maintained the clam popula-
tion over the winter. Mackie et al., (1976b) con-
cluded from studies on M. securis that in-
trapopulation variations in reproduction are
more pronounced in temporar>' than in perma-
nent aquatic habitats and that reproductive
habits may be adaptively modified. Heard (1977)
suggested that fertilization and birth can occur at
any time in an animal, but, because of relative
synchronization of individuals, a population can
display seasonal, peak periods of those activities.

Dissections of the inner gills of adult M. par-
tumeium during this study revealed that four
developmental stages of incubating young (F,) oc-
curred. These four stages, each arising from a dif-
ferent time of fertilization, have been described
by Heard (1977) and Mackie and Huggins (1976)
as follows: embryos which include all develop-
mental stages between the zygote and completed
gastrula; fetal larvae which include all devel-
opmental stages between the gastrula and the
beginning of the formation of the shell; pro-
dissoconch larvae which include all developmen-
tal stages of shelled larvae while within brood
sacs; and extra -marsupial larvae which are those
that have escaped from the brood sacs and lie
free in the interlamellar space prior to birth or
are byssally attached to the demibranch. Figure 1
shows these four developmental stages in M. par-
tumeium determined by numerous gill dissections
of adults. General size distinctions were made
between F, of the four stages of development. The

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 79

FIG. 1. Life history o/Musculium partumeium (Say). Nate the four
identified asfollous: d, disaocnnch: st, statacyst: ft, /oof,- vm, visceral

specific duration of incubation of each of the four
developmental stages is unknown for Sphaerium
and Mitsculium (Heard, 1977).

Observations of dissections of live specimens
indicated that fetal larvae show ciliary action
similar to that shown by the trochophores of Cor-
bicitla. Trochophore and veliger stages are sup-
pressed in M. partumeium, however. The pro-
dissoconch larvae exhibit direct development with
continued shell formation until the visceral mass
is completely enclosed. Internal development
takes place throughout this period. The visceral
mass is moved about in the region of the foot
while development continues. The extra-mar-
supial larvae show advanced internal structure
similar to adults. The newly released clams ap-
pear to be miniatures of the adult.

The largest extra-marsupial larvae found in
dissections of M. partumeium were 1.40 mm.
Heard (1977) found the largest in his studies to
be 1.22 mm. Thomas (1959) determined a mean
birth length for M. partumeium in a temporary

developmental stages and respective size classes. Symbols are
mass: g, gills: h, heart.

pond to be 1.6 mm, as compared to 1.44 mm in
the laboratory. The smallest to be successfully
raised was one which measured 1.25 mm in
length. During the June and January sample col-
lections of this study when young production was
high, the major size class ranged from 1.3-2.1
mm.

The smallest specimen of M. partumeium ex-
amined that contained any developmental stage
of larvae was measured at 2.58 mm in length. On-
ly embryos were present in the brood sac.
Thomas (1959) reported that ovary and testis are
present at birth in M partumeium, but neither
organ contains mature reproductive cells. The
mean length of the newborn was 1.6 mm, and the
smallest developing adult that contained gametes
was 2.1 mm long. Mackie et al., (1976b) found
gametogenesis first apparent in adult M. securis
of length 2.00-2.50 mm. They reported simul-
taneous maturation of gametes as did Thomas
(1959) for M. partumeium. Heard (1977) stated
that extra-marsupial larvae of most Sphaerium

80 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

already contain eggs and sperm, whereas gametes
are not present in S. occidentale and Musculium
after birth.

Unfortunately because of the method by which
samples were obtained, accurate brood sizes could
not be determined for M. partumeium. The true
brood sizes might have been larger than any
found in this study, since the methodology could
have led to abortion of extra-marsupial larvae.
From general observations, it was evident that
brood sizes were large, with values ranging from
2 to 33. These data were considered sufficient for
identification purposes. Gilmore (1917) listed be-
tween 10 and 20 as the brood size for M. par-
tumeium, whereas Thomas (1959) reported a
range of 2 to 30 and a mean of 10 for the same
species. Heard (1977) found as many as 14 F, per
brood sac and from 1 to 5 sacs in M. partumeium.
When dissected, older adult M. partumeium con-
tained a greater number of F, than younger
adults. An increase in generative performance
with age has been reported by Thomas (1959) and
Heard (1977) for M. partumeium and by Mackie
et a/., (1976b) for M. securis.

The life history of Corbicula has been described
by Sinclair and Isom (1963). Corbicula from the
Savannah River and the 400 area sedimentation
basin show similar developmental stages. Of ma-
jor importance is the fact that Corbicula young
are released as planktotrophic veligers or benthic
veligers at a size of approximately 0.22 mm. The
importance of this will be discussed later.

Samples of Corbicula collected January-July,
1976, from the sedimentation basin and August
25, 1976, from the Savannah River were examined
for gravidity. Specimens inspected in May and
early June were incubating veligers in the gill.
Not until August 25, 1976, were Corbicula again
found to be gravid. The sample from the Savan-
nah River, taken adjacent to the 400 area water
intake, showed Corbicula to be incubating
trochophore larvae at that time.

The findings of this study on the reproductive
period confirm reports in the literature. Sickel
(1976) examined plankton samples for Corbicula
larvae in the Altamaha River in Georgia. He
found larvae present in the water column
throughout the year, except for the month of
March, with a peak density in May. Aldridge and

McMahon (1976) reported that Corbicula have
two generations per year, a spring reproductive
period extending from mid-April to late July and
a fall reproductive period extending from late
August to late November. They found Corbicula
from Lake Arlington, Texas, with individual dai-
ly fecundities of 387.0 veligers/clam and 319.8
veligers/clam for the spring and fall reproductive
periods, respectively.

Repopulation of the Study Area Basin.

Qualitative samples collected from the wall of
the sedimentation basin and quantitative samples
collected from the floor of the basin in January
and April, 1977 were taken to determine the ex-
tent of repopulation of the basin following the
August, 1976, extermination. In January, 1977,
the wall sample indicated that M. partumeium
was repopulating the basin. The sample consisted
of 619 M. partumeium but also 11 Corbicula.
Sizes of M. partumeium ranged from 1.26 mm to
6.27 mm long, with a preponderance of 1.3-2.0
mm long young. The Corbicula ranged in length
from 1.61 mm to 5.0 mm. An examination of the
bottom material collected during January, 1977,
showed M. partumeium concentrations of
1834/m^ as compared to 856/m^ of Corbicula. More
numerous in both species were young clams in
the 1.3-2.0 mm length class. Some specimens of
both species attained lengths as great as 8.0 mm.

The results of the April, 1977 sample collec-
tions differed dramatically from the January
findings. A similar sampling effort was made in
the April sample collection from the basin wall
as was made in the January collection. Results
showed 3277 M. partumeium in the collection as
compared to 2 Corbicula. The Corbicula were 2.0
mm and 2.1 mm long, while the M. partumeium
showed a complete range of size classes. Ex-
amination of the April bottom sample revealed
M. partumeium concentrations of 1320/m^ but
Corbicula concentrations had increased to
8200/m^ Corbicula ranged in length from 0.87 to
13.9 mm with a large number of clams between
1.0 mm and 7.0 mm. Various sizes of M. par-
tumeium were collected in the sample, but the
greatest number were 4.0 mm to 6.0 mm in
length.

Vol. 9.3 (2-3)

April 23, 1979

THE NAUTILUS 81

The results of the January and April, 1977
sample collections indicated that repopulation of
the sedimentation basin was well underway.
Since newly released M. partumeium are usually
at least 1.25 mm long, it would seem that recruit-
ment from the river may span a wide distribu-
tion of sizes. Results of the variety of size classes
present in the January and April, 1977 samples
would tend to support this belief. In recent imp-
ingement and entrainment studies at the Savan-
nah River Plant, it has been determined that not
only Corbicula veligers but also benthic larvae
and juveniles are recruited in the water intakes
(Tilly, 1976; personal communication). Corbicula
are well-established in the Savannah River near
the study area. M. partumeium have not been col-
lected from the river, although the vast Savannah
River swamp would seem to be an ideal habitat
for this clam. Lack of collection has probably
resulted from the inability to put a boat in the
river at high water and the inaccessibility of the
swamp when one does get a boat in the river at
low water.

The majority of the younger clams present in
the January, 1977 sample were probably re-
cruited directly from the river, although some
might have been bom in the basin from gravid
clams recruited in the Fall. M. partumeium up to
8.0 mm in length were present in the January
sample, as well as some Corbicula of the same
size. Sinclair and Isom (1963) found Corbicula to
be sexually mature at a length of 6.5 mm. Some
reproduction in Corbicula may have been under-
way by the time of the April, 1977 collection,
since a large number of 1.0-3.0 mm long clams
were present, as well as a large number of 4.0-8.0
mm long Corbicula. M. partumeium appeared to
be prepared for an early summer reproductive
period, since most clams ranged in size from
4.0-6.0 mm long.

Interactions ofM. partumeium with Corbicula.

From a comparison of the results of the
January, 1977 collection and the April, 1977 col-
lections, the number of Corbicula increased
dramatically on the floor of the basin while the
number of M. partumeium decreased somewhat.
During the same period in which the Corbicula

|X)pulati()n increased on the floor of the basin, the
population of M. partumeium increased
dramatically on the wall of the basin.

The number of Corbicula collected from the
wall of the basin in January, 1977, was 11. In the
April, 1977, collection from the wall, when it ap-
peared that a much larger population of M. par-
tumeium was present, only 2 Corbicula were
found. During the January through July, 1976
sample collections, no Corbicula specimens were
found in the established population of M. par-
tumeium on the wall of the basin.

M. partumeium and Corbicula are able to co-
exist in the basin. The byssal-like attachment of
M partumeium may give this species a com-
petitive advantage on the basin wall. Such an
adaptation resulting in a competitive advantage
is supported by the data of Heard (1977) which
indicate that a functional larval byssus in S. oc-
cidentale and M. partumeium is an adaptation
for temporary habitats.

Several interactions, such as food or space, may
make it advantageous for M. partumeium to in-
habit the wall of the basin by attachment. Spatial
competition is a likely possibility considering the
confines of the basin. Sickel (1973) reported that
in the Altamaha River, Georgia, no unionids
were present where Corbicula were most dense,
although the habitat appeared suitable. He stated
that it was unlikely to be spatial competition
since the size of Corbicula and its density did not
appear to be great enough to exclude the much
larger unionids. Sickel (1976) later reported that
Corbicula may be excluding the juvenile unionids
which may eventually result in the loss of ende-
mic species of clams. This competitive interaction
would be more closely representative of the situa-
tion with M. partumeium. Corbicula in the
sedimentation basin and the Savannah River
ranged in maximum size from 25 mm to 35 mm
long. In comparison, M. partumeium collected
from the basin reached a maximum size of 8.0
mm in length.

There also may be spatial competition for the
wall habitat of the basin. From earlier discus-
sions, it was shown that Corbicula were present
in very few numbers in January and April, 1977
sample collections and not present at all in

82 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

Januarj'-July, 1976 sample collections although
the wall of the basin was well populated with M.
partumeium. Although Corbicula is known to
have a functional byssus (Sinclair and Isom,
1963). the size at which the clam is released from
the gills of the adult would place it at a definite
disadvantage. As mentioned earlier in the text,
the veligers of Corbicula measure approximately
0.22 mm when released. In comparison, M. par-
tumeium measures approximately 1.3 mm in
length or larger when released from the gills
(Figure 1) which would seem to give this clam a
competitive advantage over the Corbicula larvae
for the wall habitat, in this case, the preferred
habitat for M. partumeium.

Heard (1977), in evaluating fecundity in terms
of current ecological theory, determined that
Musculium and S. occidentale are "r-strategists"
in ephemeral habitats, devoting more energy to
reproduction. In contrast, other Sphaerium and
Pisidium in perennial habitats are "k-
strategists," expending greater energy on such
non-reproductive activities as maintenance.

Corbicula is an introduced species to the
United States and shows characteristics of both
an "r-strategist" and a "k-strategist." The "r-
strategies" employed by Corbicula include early
reproductive maturity and high fecundity. The
"k-strategies" include producing young that have
a greater survival probability, a long life span,
and energy for competition. It appears that M.
partumeium, normally an "r-strategist" in
ephemeral habitats, may exhibit more "k-
strategies" in the permanent aquatic habitat of
the basin and thus may be using more of the
available energy for competition. Heard (1977)
reported that where Pisidium and Sphaerium
both exist in the littoral zone of lakes, the range
of the "r-strategist" Pisidium extended into the
profundal zone, because of interactions with the
more competitive Sphaerium.

CONCLUSIONS

Musculium partumeium has retained some lar-
val form of byssal-like attachment throughout its
lifetime which enables it to inhabit the wall of
the 400 area sedimentation basin. It is not known

whether the attachment originates from a func-
tional byssus or from mucus secretions of the
foot.

Some interaction or competition may exist be-
tween M. partumeium and Corbicula. Spatial
competition is considered highly probable because
of the size differences between adult Corbicula
and adult M. partumeium. With the much larger
size, adult Corbicula may inhabit the preferred
habitat of the basin floor. In a like manner, M.
partumeium may spatially out-compete young
Corbicula for the habitat of the basin wall, since
both species are capable of byssal attachment.
Newly released M. partumeium are much larger
than the Corbicula veligers and therefore may oc-
cupy the wall habitat, in this case, the preferred
habitat for M. partumeium.

Observations on M. partumeium collected from
the basin wall did not reveal any major changes
in reproductive habits. It would be extremely dif-
ficult to document any minor variation in repro-
ductive habits, since such habits are adaptively
modified by changes in environment or habitat.

It is concluded that the adaptability of M. par-
tumeium may have made it possible for the clam
to coexist in the sedimentation basin with Cor-
bicula. Those species capable of inhabiting tem-
f)orary habitats may possess the adaptability
necessary to withstand the Corbicula invasion.

ACKNOWLEDGMENTS

This research was supported by E. I. DuPont
de Nemours and Company, Savannah River
Laboratory, through a grant awarded to the
University of South Carolina School of Public
Health. This work was submitted in partial
fulfillment of the degree of Masters of Science in
Public Health.

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April 2.'^, 1979

THE NAUTILUS 83

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Eupera eubensis (Bivalvia: Sphaeriidae) from Kansas. ./.

Fish. Res. Board Can. 33: 1652-1656.
Mackie, G. L., and S. U. Qadri. 1974. Calyculism in Musculium

seairis (Pelecypoda: Sphaeriidae) and its significance. Can.

J. Zool. 52: 977-980.
Mackie, G. L., S. U. Qadri, and A. H. Clarke, 1974a. Byssus

structure of larval forms of the fingernail clam, Musculium

securis (Prime). Gin. J. Zool. 52: 945-946.

1974b. Development of brood s;ics in Musculium

securis Bivalvia: Sphaeriidae. The Nautilus 88(4): 109-111.
. 1976a. Intra.specific variations in growth, birth pe-

riods, and longevity of Muscuiium securis (Bivalvia: Sphaeri-
idae) near Ottawa. Canada, Mulonihuiio 15(2): 4liV446.
. 1976b. Reproductive habits of four populations of

Musculium securis (Bivalvia: Sphaeriidae) near Ottawa,
Canada. The Nautilus 90(2): 76-86.

Monk, G. R. 1928. The anatomy and life history of a
freshwater mollusk of the genus Sphaerium. J. Morph. 45:
473-503.

Rodgers, J. H., Jr., D. S. Cherry, J. R. Clark, K. L. Dickson,
and J. Cairns, Jr. 1977. The invasion of Asiatic clam, Cor-
bicula manilensis in the New River. Virginia. The Nautilus
91(2): 43-46

Sickel, J. B. 1973. A new record of Corbiada manilensis
(Philippi) in the Southern Atlantic Slope region of Georgia.
The Nautilus 87 {iy.n-\2.

. 1976. An ecological study of the Asiatic clam,

Corbicula manilensis (Philippi, 1841) in the Altamaha
River, Georgia, with emphasis on population dynamics, pro-
ductivity, and control methods. As abstracted in Corbicula
Newsletter, ed. J. S. Mattice, Oak Ridge National
Laboratory, Vol. 2(1), 1977.

Sinclair, R. M. 1964. Clam pests in Tennessee water supplies.
Jmir A WWA 56(5): 592-.599.

. 1971. Annotated bibliography on the exotic

bivalve Corbiada in North America, 1900-1971. Sterkiana
43: 11-18.

Sinclair, R. M. and W. M. Ingram. 1961. A new record for the
Asiatic clam in the United States, the Tennessee River. The
Nautilus 7i{3):lU-nS.

Sinclair, R. M. and B. G. Isom. 1963. Further studies on the
introduced Asiatic clam (Corbiada) in Tennessee. Tennessee
Department of Public Health. 75 pp.

Sterki, Victor. 1909. Some observations and notes on
Musmdium. The Nautilus ^(2): 17-19.

Thomas, G. J. 1959. Self-fertilization and production of young
in a sphaeriid clam. The Nautilus 72(4): 131-140.

. 1963 Study of a population of sphaeriid clams in

a temporary pond. The Nautilus 77(2): 37-43.

. 1965. Growth in one species of sphaeriid clam.

The Nautilus 79(2): 41 -5i.

Tilly, L. J. 1976. Persmal communication: Research super-
visor. Savannah River Plant, Aiken, South Carolina.

Yonge, C. M. 1962. On the primitive significance of the byssus
in the Bivalvia and its effects in evolution. J. mar. biol.
Ass. r. A'. 42: 113-12.5.

Recent

Akibumi Teramachi, an amateur conchologist,
artist, and well-known Japanese shell collector
died in Kyoto, Japan, at the age of 80, on
December 6, 1978. At the age of 24 he developed
tuberculosis and went to Wakayama Prefecture
for his health. There he became an avid shell col-
lector, and published his first two papers on con-
chology in the Venvs. vol. 2, in 1930. Two genera.

Death

Temmachia and Akibumia, and several species of
moUusks were named after him, especially by
Kuroda and Habe. Cypraea katsuae was named
after his wife. Some of the types in his collection
were sold from time to time, and the holotype,
for instance, of Teramaehia tibiaeformis Kuroda,
is now in the Academy of Natural Sciences of
Philadelphia.

84 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

REDISCOVERY OF A PRESUMED EXTINCT RIVER MUSSEL,
DYSNOMIA SULCATA (UNIONIDAE)

Billy G. Isom', Charles Gooch', and Sally D. Dennis^

Several commercial mussel boats were sighted
on the Cumberland River in July 1976. A visit
was made to the area on September 1, 1976, to
determine the species of mussels being taken
commercially. Among the species found were
several specimens of one that had been presumed
extinct (Stansbery. 1970) or reduced to a single
river system (Stansbery, 1971). The species was
later taken live near Cumberland River at mile
296.8, the same general area in which the mussel
boats had been working. This species is believed
to be confined to this portion of the Cumberland
River in Tennessee.

Lea (1829) described the species as "Shell sub-
elliptical, inequilateral, ventricose, slightly
marginate; valves thick; beaks nearly terminal;
cardinal and lateral teeth large, and double in
both valves; nacre purple." The type locality was
listed by Lea as Ohio in his plate 8, fig. 12.

Dysnomia sulcata (Lea, 1829) was reported to
exist in the Cumberland River by Wilson and
Clark (1914), who commented on its distribution:
"Although this species seems to be pretty well
distributed along a considerable stretch of river,
we obtained only occasional examples here and
there along the shore ... It can probably be pro-
cured in large numbers during low water."

"It is common enough to be pretty well known
to the clammers, who call it 'peewee' on account
of its small size, or 'cat's-claw' because of the
peculiar clawlike structure on the marsupial ex-
pansion of the female."

Ortmann (1925) provided good locality records
for I). !iiilrata. However, he considered the species
an "immigrant" in both the Cumberland and
Tennessee Rivers, its principal distribution
centered clearly in the Ohio and Wabash Rivers.

Neal and Allen (19(yl) reported finding only
one sf)ecimen during their study of the mussels of

'Tenne&see Valley Authority. E&D Building, Muscle Shoals,
Alabama .^Sfifin

'Tennessee Valley .Authority, F(jrestry Building, Norris, Ten-
nessee 37828

the upper Cumberland River. This specimen was
found at Neeleys Ford near Burkesville, Ken-
tucky.

Stansbery (1970) stated that "Tlie big river D.
a. mlcata form having a purple nacre may be ex-
tinct, but the white-nacred D. .s. perobliquioi is
still occasionally found in streams tributary to
western Lake Erie or Lake St. Clair." However,
Stansbery (1971) stated that D. f^ulcata was
reduced to a single river system, the Green River
in Kentucky'.

Lack of recent locality records for this species
may result from limited amount of collecting be-
ing done in big rivers, especially the Cumberland
River. The last comprehensive study of the mid-
dle and lower Cumberland River was by Wilson
and Clark (1914).

We wish to thank Steven A. Ahlstedt for his
assi-stance in this project.

REFERENCES
LITERATURE CITED

Lea. Isaac, 1829 (18:5)). Observation on thie genus L'nio
together with descriptions of eighteen species; and of the
genus Sifiiiplnfiiotfi. now separated from the family of
Naiades, containing nine species. Tmm. Ainer. Pliilim. Six:
3:4.30-«l,pl.8.fig.l2.

Neel, .Joe K. and William R. .Allen. 1964. The mussel fauna of
the upper Cumberland Basin before its impoundment.
il/a/nfo/oyfVil (.3): 427-459.

Ortmann, A. E. 1925. The Naiad fauna of the Tennessee River
below Walden Gorge. /I »ienV«« Midi Nat. 9(7): :321-372.

Stansben,', David H. 1970. Eastern Freshw^ater Mollusks (I)
The Mississippi and St. Lawrence River Systems. In: Pni-
cfciliiiyy (if the Amrr. Malaaihiyicnl l'iu<i>i Si/niixisiiini on
Rare ami F.ndangered Mollush. Ed. by A. H. Clarke, (1968):
p. 19.

. 1971. Rare and endangered freshwater mollusks

in Eastern L'nited States. In: Hare and Endangered
Mollusks (Naiads) of the U.S. Edited by Jorgensen and
Sharp. Issued by the U.S. Dept of Interior. Region 3: pp.
.5-18andl8e.

Wilson. Charles B. and H. Walton Clark. 1914. The Musi^els of
the Cumberliuid River and its Tributaries. Reixirt, W. S.
Fish, Conim., Washington. D.C., No. 781.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 85

A REVIEW OF THE SYSTEMATICS OF CYLICHNELLA GABB
(OPISTHOBRANCHIA: SCAPHANDRIDAE)

Terrence M. Gosliner

Department of Zoolog>'

University of New Hampshire

Durham, N. H. 03824

ABSTRACT

.4 nin)-i)fi<>l<igirnl fttiidy ivm^ made oftii.r sperip^ of the geniif; Cylichnella Gahb. 1873.
Cylichnella oryza wan studied anatornieaUyfor the first time. Coniparison of the in-
fomiatum obtained in this study with that in the literature suggests that Utriculastra
Thiele, 1925, should he regarded as a junior synonym o/ Cylichnella. C. canaliculata
and C. inculta, while similar inform, are distinct species. C. cerealis is nuiintained as
a valid species while C. eximia is suppressed as a junior synonym ofC. culcitella.

INTRODUCTION

The recent works of Marcus (1974, 1977), Rud-
man (1971, 1973), Bouchet (1975) have dealt ex-
tensively with the comparative morphology of
members of the Cephalaspidea. Many species
possess shells which are similar in form yet have
dramatically divergent internal morphology. The
systematics of the Cephalaspidea has been more
clearly defined as a result of these studies.

Two genera of the Scaphandridae, Cylichnella
Gabb, 1873 and Utriculastra Thiele, 1925, have dif-
ferent shell types. Cylichnella has an involuted
spire while Utriculastra possesses a projecting apex
of varying prominence (Marcus, 1958; Marcus,
1977). Marcus (1977) noted that the gizzard and
radula of members of both genera are virtually
identical but differentiated the genera on the basis
of several other criteria. Marcus (1977) described
two subgenera, U. (Utriculastra) and U. (Tor-
mtstra). My preliminary examinations suggest that
a more detailed analysis of the status of Cylichnella
and Utriculastra is warranted. The work of Marcus
(1977) supplied an excellent analysis of
Utriculastra and its component subgenera and
species and provides the basis of comparison for the
work presented in this paper.

I would like to thank Dr. Ruth Turner of Har-
vard University for her encouragement and for her
critical comments, Dr. Eveline Marcus of the
University of Sao Paulo, Brazil for her suggestions
and enthusiasm, Dr. M. Patricia Morse of North-
eastern University, Mr. Kee Muschenheim of Yale
University and Mr. Gale Sphon of the Los Angeles

County Museum for providing specimens. I would
particularly like to thank Dr. Larry Harris of the
University of the New Hampshire for his guidance
and friendship and for his help in collecting
specimens in Nova Scotia.

MATERIALS AND METHODS
Three specimens of Cylichnella cerealis (Gould,
1852) were collected from Bodega Harbor, Bodega
Bay, California (lat. 38°18'N.; long. 123°03' W.) on
June 17, 1976. Numerous specimens of C. inculta
(Gould, 1856) were collected from Morro Bay,
California (lat. 35°20' N.; long. 120°50' W.) on July
17, 1976. C. canaliculata (Say, 1826) was collected
on August 17, 19, 26, 1977 from several localities in
Nova Scotia and New Brunswick, and on Sep-
tember 3, 1977 from Pt. Judith, Rhode Island (lat.
4r24' N.; long. 72°30' W.) Additional specimens of
C. canalicxdata from Long Island Sound were
provided by Mr. Kee Muschenheim. Several
specimens of C culcitella (Gould, 1852) from San
Miguel Island, California, (lat. 35°59' N.; 120°25'
W.) were loaned by the Los Angeles County
Museum. Three specimens of C. bidentata (Orbigny,
1841) from the Eveline Marcus collection were
made available by the Department of Mollusks,
Museum of Comparative Zoology, Harvard Univer-
sity. Numerous specimens of C. oryza (Totten,
1835), dredged from Long Island Sound, were
provided by Mr. Kee Muschenheim.

Specimens were observed alive whenever
possible and were dissected for morphological com-
parison. Several (circa 5-10) individuals of each

86 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

species were dissected to determine intra as well as
interspecific variation. The anatomy of the shell,
postero-lateral e.xtension of the mantle, radula.
jaw, gizzard plates, nervous system and reproduc-
tive system was studied for each species.

Cylichnella Gabb, 1873

type species: Bulla bidentata Orbigny , 1841
1. C. ranaliculata (Say. 1826)

Specimens collected from three different
localities in New Brunswick and Nova Scotia
exhibited different shell characteristics. Specimens
fi-om Parlee Beach. Shediac, N. B. (lat. 46° 12' N.;
long. 64°30' W.) an open sandy beach on the Nor-
thumberland Strait, have a spire which is elongate
and clean; those from Pictou Harbor, N. S., (lat.
45°40' N.; long. 62° 45' W.) a quiet area of mixed
fine sand and mud have an elongate spire which is
covered with sand and mud; and the spires of all
specimens (100) from Bras d'Or Lake, N. S., (lat.
46°05' N.; long. 60° 48' W.) a large calm estuary, are
almost completely eroded. The shell ranges from 3..5
to 6.0 mm in length. In all cases the periostracum is
thin and transparent. The postero-lateral elabora-
tion of the mantle edge is .short.

The radular formula in five specimens ranges
from 12-1.") X 1. 1. 1. Tlie jaws are cuticular and
possess platelets as depicted by Marcus (1977). The
gizzard plates of C. canaliculata are similar to that
described by Marcus (1977) with a wide heart
shaped dorsal plate and two narrow sub-equal
latero-ventral plates. In six specimens observed the
large gizzard plates ranged in length from .85 to 1.0
mm while the lateral plates ranged from .95 to 1.25
mm in length.

The nervous system (Fig. 1) consists of two large
cerebral and two large pedal ganglia. The cerebral
and pedal commissures are approximately equal in
length. The left and right pleural ganglia are small
and connect to the cerebal and pedal ganglia. Im-
mediately posterior to the right pleural ganglion
lies the right parietal ganglion. From there the
right visceral nerve runs posteriorly to the suprain-
testinal ganglion which is situated at the level of
the mid-portion of the gizzard. At the dorsal .sur-
face of the ganglion the short osphradial nerve con-
nects with the vestigial osphradium. Near its
posterior limit the right visceral nerve crosses the

left visceral nerve dorsally and loops anteriorly to
the small genital ganglion. From the genital
ganglion emanates the genital nerve and the left
visceral nerve. After a moderate distance the left
visceral ner\'e gives rise to the closely as.sociated
visceral and sub-intestinal ganglia. Midway be-
tween the left pleural ganglion and the sub-intes-
tinal ganglion the left visceral nerve gives rise to
the pallial nerve. At this juncture the visceral
nerve is slightly thickened yet does not form a
distinct pallial ganglion.

The reproductive system of C. canaliculata (Fig.
2) consists of a series of diffuse lobes of the ovotestis
which are interdigitated with the digestive gland.
The narrow pre-ampuUary duct is short and widens
intf) an ampulla consisting of numerous con-
volutions. The ampulla narrows into an elongate
and relatively straight post-ampullary duct. A
semiserial receptaculum seminis (terminology
following Edmunds. 1970) enters the post-
ampullary duct which continues distally to the
common genital atrium. Also entering the com-
mon atrium are the large female accessory organs,
the albumen and mucus glands. The duct of the
spherical bursa copulatrix also enters the common
atrium at this point. From the gonopore an open
seminal groove runs anteriorly to the protrusible
cephalic penis.

2. C. inculta (Gould, 1856)

The shell of C. inculta has an elevated spire. The
protoconch may be present or eroded. The
periostracum is transparent. In the forty specimens
studied the shell is 3.5 to 6.0 mm long. The postero-
lateral margin of the mantle is produced into a
short extension. The radular formula in four
specimens varies from 18-20 X 1.1.1. The jaws are
thin and cuticular and possess platelets as depicted
by Marcus (1977). The gizzard is similar to that
described by Marcus (1977). The dorsal plate is
broad and heart shaped and ranges from .80-1.05
mm in length. The narrow paired gizzard plates are
.9.5 to 1.10mm in length.

The central nervous system and reproductive
system are indistinguishable from those of C.
canaliculata with the exception of the penis. In C.
inculta the prostate is thick and elongate while in
C. canaliculata it is much thinner and shorter.

Vol. 98 (2-3)

April 23, 1979

THE NAUTILUS 87

FIGS. 1-4. Cylichnella canaliculata (Saij). 1, central nervous
syxtem (scale 1.0 mm). 2, reproductive system (scale 0.5 mm).
3, Cylichnella culcitella fGoiiUI) (xralr 1.0). 3a, receptafuliim

Legend to Lettering

a-ampulla
ag-albumen gland
bc-bursa copulatrix
c-eerebral ganglia
g-genital ganglion
ga-genital aperture
me-membrane gland
mg-mucus gland
ot-ovotestis

p-penis

pa-parietal ganglion
pl-pleural ganglion
pr- prostate

rs-receptaeulum seminis
sb-subintestinal ganglion
sp-supraintestinal ganglion
v-visceral ganglion

seminis. 3b, entire reproductive system. 4, Cylichnella biden-
tata (Orhigny) (scale 0.2 mm), reproductive system.

3. C. culcitella (Gould, 1852)

The shell is 9.5 to 15.0 mm in length in the 20
specimens observed. The spire is slightly to
moderately elevated. The periostracum is trans-
parent-browTi with numerous spiral striations.
The length of the po.stero-lateral mantle e.xtension
varies from moderate to extremely long. It recurves
to the right side of the animal and extends ven-
trally to the ventral surface of the body whorl.

88 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

In C. culcitella there are 23, 24 and 28 pairs of
lateral teeth in three individuals observed. In the
specimen with 24 pairs of lateral teeth there is a
row of 14 small, rectangular rachidian teeth, while
rachidians are entirely absent in the other two in-
dividuals from the same collection. There are 55 to
66 denticles along the entire margin of the lateral
teeth. The jaws consist of a thin membranous
cuticle without platelets. In four specimens ob-
served the small unequal gizzard plate is laterally
flattened and is 1.6 to 2.9 mm long. The large sub-
equal gizzard plates are 2.4 to 4.9 mm long.

The reproductive system of C. culcitella is
similar to that of C. canaliculata except that the
receptaculum seminis is serial in one specimen
(Fig. 3b) and semi-serial in two other specimens
(Fig. 'ia). The penis and prostate in three specimens
observed is similar to that described by Marcus
(1977) and ranges from 7 to 13 mm in length.

4. C. cerealis (Gould, 1852)

The shell is 6.5 to 11.0 mm in length and has a
moderately elevated spire. The periostracum is
transparent with brown spiral striations of varying
prominence. The postero-lateral extension of the
mantle is elongate and recurves to the left along
the dorsal surface of the body whorl.

The radula in the three specimens observed con-
sists of 17, 19 and 21 pairs of lateral teeth. In no
case is there any trace of rachidian teeth. The jaws
are thin and membranous without platelets. In the
four specimens observed the small, uneven gizzard
plate is dorso-ventrally flattened and 1.0 to 1.5 mm
long. The large subequal plates are 1.5 to 2.5 mm
long.

The nervous system is identical to that described
for C. canaliculata.

The reproductive system is the same as in C.
canaliculata except that the receptaculum seminis
in one specimen is serial and semi -serial in
another, as in C. culcitella. In the three specimens
studied the penis consists of an elongate, thickened
prostate and a conical papilla which lacks
papulations. The penis ranges from 8 to 12 mm in
length.

5. Cylichnella bidentata (Orbigny, 1841)

The shell is elongate and cylindrical with a
bulloid apex. In the three specimens studied the
shell is 2.8 to 3.1 mm long and 1.4 to 1.6 mm wide.
The periostracum is thin and transparent without

striations. The postero-lateral extension of the
mantle is of a moderate length.

The radular formula in two specimens dissected
consists of 14 and 15 X 1.1.1. The jaws are
thickened at the anterior edge but lack any
platelets. The gizzard consists of a wide heart
shaped dorsal plate which in two individuals
ranges from .55 to 1.0 mm in length. The narrow
paired plates range from 0.6 to 1.0 mm in length.

The nervous system and the reproductive system
(Fig. 4) are not significantly different from that of
Cylichnella canaliculata. The penis is identical to
that described by Marcus (1958).
6. C: oryza (Totten, 1835)

The shell (Fig. 5) is orbicular with a depressed
bulloid apex. The preserved animals vary in length
from 1.4 to 2.8 mm and 0.7 to 2.0 mm in width. The
postero-lateral extension of the mantle is ex-
tremely short.

In the two specimens examined the radula (Fig.
6) has a formula of 16-17 X 1.1.1. There are 10 to 16
denticles on the inner margin of the laterals. The
jaws consist of a thin chitinous cuticle which lacks
platelets. The gizzard (Fig. 7) consists of a large
heart shaped dorsal plate and two smaller,
subequal ventro-lateral plates. The dorsal plate in
the one specimen examined is 1.35 mm long and .97
mm wide. The two subequal plates are 1.25 mm and
1.22 mm in length and .51 mm and .50 mm wide,
respectively.

The central nervous system (Fig. 8) appears to be
entirely euthyneurous as the right visceral nerve
does not cross the left visceral nerve. The relation-
ships of the ganglia are similar to those of C.
canaliculata except that the visceral nerves are
shortened.

The reproductive system of C. oryza (Fig. 9, 10)
closely resembles that of C. canaliculata. The only
difference is that the receptaculum seminis is
spherical with an elongate duct in both specimens
dissected. The penis consists of a wide prostate
which narrows anteriorly for most of its length.
The penial papilla is broad without any armature
or papillae.

DISCUSSION

The morphological similarities between the
species described is striking. Marcus (1977, p. 17)
noted that the radular teeth and gizzard plates of
Cylichnella canaliculata (as Utriculastra) and

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 89

FIGS. 5-10, Cylichnella oryza (Totten). 5, shell (scale 0.3 mm).
6, radular teeth (scale 10 mj/ / 7, gizzard plates (scale 0.5

mm). 8, central nervous system (scale 0.3). 9, penis and pro-
state (scale 0.1 mm). 10, reproductive system (scale 0.25 mm).

90 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

Cylichnella hidentata were identical yet stated
that "the depressed apex (of the shell), the shape of
the head shield, posterior adherence and the male
organ are different in both forms and justify
generic separation." A detailed examination of
these differences is required.

The presence of a bulloid shell in Cylichnella ver-
sus an elevated spire in Utriculastra appears to be
a useful character for generic separation. However,
if one examines the shells of species which Marcus
considered as members of Utriculastra one en-
counters a wide range of form. C. rolleri (Marcus,
1977) generally h;i.s an e.xtremely elongate spire
(unpublished data) while in C. eximia the spire is
scarcely elevated (Marcus, 1977). Most other species
are somewhat intermediate between these two in
spire elevation.

The shape of the head shield in C. carmliculata,
when fully extended, is rectangular and more
elongate than shown by Marcus (1977, Fig. 23). The
posterior lobes of the head shield are rounded in C.
canaliculata whereas they are acutely pointed in C.
hidentata. The lobes of C. rolleri. however, are
elongate and acute as in C. hidentata. I am unable
to discern any consistent difference in the shape of
the head shield between species considered as
Cylichnella and Utrifulmtrn by Marcus (1977).

It appears to me that the "posterior adherence"
(Marcus, 1958) of Cylichnella bidentatn is
homologous with the "cloacal tentacle" (Marcus,
1977) found in C. cerealis, C. culcitella and Tor-
natina conspicua. I prefer the term posterior ex-
tension of the mantle. Cylichnella oryza lacks any
noticeable extension of the mantle while in C. in-
cut ta and C. canaliculata it is extremely short. In
specimens of C. cerealis from Bodega Harbor the
extension was as highly elaborated as in Tomatina
conspicua. The length of the extension varies in
specimens of C culcitella from San Miguel Island.
There seems to be no consistent difference between
Cylichnella and Utriculastra with respect to this
character.

The final character on which Marcus (1977)
based her separation of Cylichnella and
Utriculastra was the structure of the penis. The
papilla of C. hidentata bears a row of papillae along
its margin (Marcus, 1958, present study). In C.
culcitella the penis contains similar papulations
(Marcus, 1977). The penis of C. inculta, C.

rnnnlinilntn and C aryza lacks any papulations.
Marcus (1974) has shown that some species of
Scaphander posses papulations on the penial
papilla while others lack them entirely. Simi-
larly, Rudman (1974) has shown that Aglnja
ocelligera has a penial papilla with numerous
papulations while other members of the genus
have a naked penis. There seems to be little basis
for separation of Cylichnella and Utriculastra
with regard to the penis.

The nervous systems of all species of Cylich-
nella in this study were virtually identical with
the exception of C. oryza which is completely
euthyneurous yet has the same configuration of
ganglia. Though all other species observed in this
study, including C hidentata differ slightly from
C (rryza their differences are not regarded as
having taxonomic importance.

In the examination of the reproductive systems
of the six species observed in this study the most
substantial difference occurred within the species,
C culcitella and C cerealis. In both species the
receptaculum seminis may be either serial or semi-
serial. Since the greatest difference observed is of
an intraspecific nature there is no basis for
separating genera.

When the observed species of Cylichnella are
compared there is no characteristic which clearly
differentiates them at the supraspecific level. The
differences in the radula and gizzard of Marcus'
two subgenera Utriculastra. U (Utriculastra) and
['. (Tonuistra). are more substantial than those
between U. (Utriculastra) and Cylichnella. I
feel that the taxa Cylichnella and Utricula.'^tm
form a natural, monophyletic genus and should
be regarded as Cylinchnella Gabb. 1873, on the
basis of priority. Utriculastra is regarded as the
junior synonym.

Marcus (1977) described two subgenera of
Utriculastra, U. (Utriculastra) and U. (Tomastra).
U (Utriculastra) is characterized by having a
deltoid unpaired gizzard plate while ['. (Tor-
nastra) has a round unpaired plate. However, the
vast majority of morphological characteristics (e.g.
shell, radula, nervous and reproductive systems)
are virtually identical between species placed in
both subgenera. In Philine, the monotypic genus of
the closely allied Philinidae, the shape of the giz-
zard plates varies considerably or may be absent

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 91

but no subgeneric separation is made. I feel that
the separation of Cylichnella is not useful as it ap-
pears to form a natural generic taxon. I therefore
also supress Tomastra as a junior synon>Tn of
Ci//(W;«e//aGabb, 1872.

The large number of synonyms of Cylichnella
canaiieulata attests to the taxonomic confusion
regarding this species. Wells and Wells (1962)
examined numerous specimens of Cylichnella from
North Carolina. They maintained that two species
were present, Retttsa canaiieulata and Acteocina
candei. Although closely allied, the species were
placed in separate genera, as the absence of a
radula in Retusa ohtusa. the type species oi Rctusa.
had not been verified. Subsequent study has con-
firmed that a radula is wanting in Retusa ohtusa
(personal observation) and that it is inappro-
priate to place C. canaiieulata in Retusa. Wells and
Wells regarded the two species as being distinct on
the following bases: slight conchological dif-
ferences, the presence of more numerous denticles
on the rachidian and lateral teeth of the radula in
C candei and an offehore distribution of C. candei
vidth an estuarine, inshore distribution in C.
canaiieulata. Wells and Wells described an entirely
contained developmental pattern for C.
canaiieulata. Franz (1971) examined the develop-
mental biologv' of C. canaiieulata from Connecticut
and determined that the species e.xhibits a
plankotrophic pattern. He offered several possible
explanations for this discrepancy. My observations
of an estuarine population in Pictou Harbor, Nova
Scotia, confirm that the species has planktotrophic
development. Marcus (1977) discussed the criteria
used to separate the two species and suggested that
intermediates in conchological and radular mor-
phology are common. She also noted that these
characteristics cannot be correlated with estuarine
or offshore distribution and that C. candei should
be regarded as a junior synonym of C. canaiieulata.
My observations of C. canaiieulata are entirely sup-
portive of Marcus' findings.

Cylichnella canaiieulata is morphologically very
similar to C. inculta. C. canaiieulata has 12 to 15
rows of radular teeth while C. inculta has 17 to 20
rows. The large dorsal gizzard plate of C. incidta is
broader than in C. canaiieulata and also contains a
proportionately larger thickened central portion.
The penis of C. iiiculta contains a thicker and

longer prostate than that of C. canaiieulata. While
these differences are minor they do appear to be
consistent and warrant specific separation.

Marcus (1977) stated that C. cereali's was distinct
from C. eximia and C. culcitella. The material from
Bodega Harbor supports this contention. The un-
paired gizzard plate is dorso-ventrally flattened
rather than laterally compressed. The lateral teeth
in C. cerealis possess 20 to 37 denticles compared to
40 reported for C. eximia and 55 to 66 for C.
culcitella. Ball's (1922) contention that C. cerealis
are young C. culcitella is refuted since all
specimens collected at Bodega Harbor were
sexually mature and were collected with egg
masses.

The separation of C. eximia and C. culcitella
seems more difficult. Marcus (1977) stated that
they were distinguished by their radular teeth,
penis and gizzard, yet described the radula of C.
culcitella as corresponding "to that of eximia". The
gizzard plates depicted for C. culcitella are slightly
more oval than those of C. eximia (Marcus, 1977,
figs. 57, 68, 69, 70, 74) yet specimens from San
Miguel Island showed similar variation. The penis
and prostate was 20 mm long in C. eximia and 3
mm long in C. culcitella in specimens of approx-
imately equal length. Specimens studied in this
paper had penis and prostate lengths of 7. 9 and 13
mm. Due to the intermediate length of the penis
along with similar morphology of the other systems
the two species are here considered as s>Tion>TTious
with C. culcitella (Gould, 1852) having priority.

Based on the anatomical work I have undertaken
I propose the following taxonomic arrangement:

Genus Cylichnella Gabb, 1873

Cylichtiella Gabb. 187:3: 273. {i\-pe siiecies: Biilln hidoitnta Or-

bigny, 18-11)
Utriailastra Thiele, 1925: 235. (type species; Volnaria

canaiieulata Say, 1826)
Tamastra Marcus, 1977: 5. (tjTJe species: Bulla eximia Baird.

18&3)

Cylichnella biden lata (Orbigny, 1841)

Bulla bidentata Orbigny, 1841.

Cylichnella bidentata (Orbigny, 1841) Gabb, 1873.

Cylichnella canaiieulata (Say, 1826)

Viiharia canaiieulata Say, 1826.
Bulla candei Orbigny, 1841.

92 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

Utriatlus cavdiculatus (Say. 1826) Watson. 1886.
Tormtina cmdiculata (Say. 1826) Pilsbry. 1895.
Tormtim candei (Orbigny. 1841) Pilsbry. 189,5.
Retusa (i'triadastmjcanalicutata (Say. 1826)Thiele. 1925.
Artaeociyia candei (Orbigny. 1841) Carcelles. 1944.
Acteodna canaliculata (Say, 1826) Perrv' and Schwengel. 19.55.
Retusa candei (Orbigny, 1841) Abbott, 19,58.
Acteodna candei (Orbigny, 1841) Wells and Wells. 1962.
Utriailoftra (i'triculastm) canalicidata (Say, 1826) Marcus,
1977.

Cylichnella inculta (Gould, 18.56)

Tomatina inculta Gould, 18.56.

Utricidaatra H'trindastm) inculta (Gould. 18.56) Marcus. 1977.

Cylichnella cerealis (Gould, 1852)

Bulla cerealis Gould, 18.52

Utriadastm (Tornastral cerealis (Gould. 18.52) Marcus. 1977.

Cylichnella culcitella (Gould, 1852)

Bulla ndcitetta Gould. ia52

Btdlina eximia Baird, 186.3.

Utricidaatra (Tomastra) culcitella (Gould, 1&52) Marcus, 1977.

Utricidaatra (Ti'mastra) erimia (Baird. 18S3) Marcus. 1977.

Cylichnella oryza (Totten, 1835)

Bulla (rryzaTottenASS^.

Cylichnella oryza (Totten, 1835) Marcus, 1958.

Cylichnella knockeri (E. A. Smith, 1872)

Tomatina knockeri Smith, 1872

Utriculastra (Tormstra) knockeri (E. A. Smith. 1872) Marcus,
1977.

Cylichnella roUeri (Marcus, 1977)

Utrindastra (Tornastral rolleri Marcus, 1977.

Other species possibly belong in the genus
Cylichnella (Marcus, 19.58: 8: Marcus. 1977:(i) but
cannot be assigned with certainty until they have
been studied morphologically.

LITERATURE CITED

Bouchet, Philippe. 1975. Opisthobranches de profondeur de I'o-

cean Atlantique. I. Cephalaspidea. Cahiers de Biologie

Marine 16: m-'i^o.
Dall. William H. 1922 A note on Arteocina. The Nautilus 35: 96.
Edmunds. Malcolm. 1970. Opisthobranchiate Mollusca from

Tanzania. II. Ek)lidacea (Cuthonidae. Piseinotecidae and

Facelinidae). I'nic. Malac. Sac. Limdim 39: 15-.57.
Franz. David. 1971. Development and metamorphosis of the

gastropod Acteocinn canalicidata (Say). Trans. Amer. Micros.

Soc. 90(2): 174-182
Gabb, William M. 1873. Description of some new genera of

Mollusca. Proc. Acad. Nat Sci. Philadelphia 1872: 270-274.
Marcus, Ernst. 1956. Notes on Opisthobranchia. Bol. Inst.

Oceana. S. Pauh, 7(1958): 31-79.
19.58. On western Atlantic opisthobranch

gastropods. Amer. Mus. Novitates, no. 1906: 1-82.
Marcus, Eveline duIBois-Reymond. 1974. On some Cephalaspidea

(Gastropoda: Opisthobranchia) from the western and middle

Atlantic. Bh//. Mar. Sci 14(2): 3(K)-371.
1977. On the genus Tomatina and related forms.

Jofurn. Moll Stiidicx (suppl.2): 1-.3.5.
Rudman, W. B. 1971. On the opisthobranch genus Haminoea

Turton and Kingston. Pacific Sci. 25: 549-.S59.
1973. The genus Philine (Opisthobranchia,

Gastropoda). Pnic. Malac. Snc. London 40(3): 171-187.
. 1974. A comparison of Chflidoiiura. Navanax and

Aylaja with other genera of the .^gtajidae (Opisthobranchia:
Ga.stropoda). Ziiol. J. IJniiean Soc. London 54: 178-212.

Thiele. .Johannes. 1925. Gastropoda der Deutschen Tiefsse-
Expedition Pt. 2. Wi.ss. Eiyebnisse dcr Deutschen Tiefsee-
Krpedition 17: .37-382.

Wells, Harry and Mary .lane Wells. 1962. The distinction be-
tween Acteodna candei and Retusa canaliculata. The
Nautibis 75(3): 87-93.

NEWS

Malacological
The main archives for the American Mala-
cological Union have now been removed from the
Delaware Museum of Natural History and placed
in more convenient and accessible quarters in the
Department of Malacology, Academy of Natural
Sciences of Philadelphia, 19th and The Parkway,
Philadelphia, PA 19103 (stewardship is in the
hands of Dr. George M. Davis; phone 1-21,5-
299-1132).

Archives Moved

The archives contain documents, correspond-
ence, photographs and information on about 1.50()
professional and amateur American malacolo-
gists, and are available for e.xamination by
serious students of historical malacology. New
material, e.specially of historical value, is most
welwme at the new center, and will be properly
curated and preserved.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 93

SHELL SPINULES OF THE BIVALVE LYONSIA HYALINA'

Robert S. Prezant

College of Marine Studies
University of Delaware
Lewes, Delaware 19958

ABSTRACT

Sihall. Clinical pnijcctiims of the periostmmm cover the outer shell surfaces (f
the hirnlve Lyonsia hyalina Conrad. These radially arranged npimden help en-
tangle a mucoid secretion produced hy niaidle glands and aid in the retention of
sand grains u-hich adhere to the shell. Vie sand-corer helps stabilize the bivalve in
the s^ibstriifuui and may lend some protection to ds thni shell.

Many members of the bivalve family Lyonsi-
idae have the curious habit of attaching sand
grains to the outside of their shells. Of the three
genera of this family, Lyonsia is typically found
partially buried with at least some portion of its
shell covered with adhering sediment. Entodesma.
a rock-crevice nestler, and Mytilimeria, found
embedded within compound tunicates, will attach
some sediment to their shells if grown within a
sand substratum (Yonge, 1952). The ability of
Lyonsia to glue sand to its valves was previously
attributed to a minutely fringed (Morris, 1973;
Emerson and Jacobson, 1976) or sticky (Yonge,
1952) periostracum. Prezant (1979) showed that
small, multicellular glands which line the mantle
edge of L. hyalina secrete a mucoid product over
the periostracum, and it is this which is responsi-
ble for adhesion of sand.

The superfamily Pandoracea has many in-
faunal genera, including Lyonsia, which are
described as having "granular" shell surfaces. The
granulations or spinulations increase shell sur-
face area and help stabilize the bivalve within
the substratum (Aller, 1974). The small spines of
Lyonsia are often obscured by adhering sand, and
are thus not exposed to the substratum to aid in
stabilization. This investigation was thus de-
signed to examine the role of these minute pro-
jections relative to the attachment of sediment to
the shell of L. hyalina.

'University of Delaware, College of Marine Studies Contribu-
tion No. 131.

Methods

Lyonsia hyalina were collected from Delaware
Bay from a muddy-sand substratum at a depth of
about 15 meters. Shells were gently cleared of
most adhering sand grains with a fine camel's
hair brush. Valves were carefully opened and the
animal removed. Shells were then rinsed in
distilled water, and some were dipped in 0.53%
sodium hypochlorite (10% commercial Clorox)
and some in 20% 1 N hydrochloric acid for 30
seconds, and again rinsed in distilled water.
Valves were then dried for 48 hours in a 60°C
oven. Dry shells were fractured, and fragments
were mounted on scanning electron microscope
stubs with silver paint, coated with gold, and ex-
amined on a Cambridge scanning electron
microscope.

Results

The nacreous shell of Lyonsia hyalina is thin
and fragile but has a well developed periostracum
with numerous periostracal striations which
radiate from the umbones. A surface view at low-
magnification of a partially cleaned shell (Fig. 1)
reveals the prominent striations and minute
spines which run parallel to the radial sculptur-
ing. There are 7 to 8 columns of these spinules
between each pair of periostracal striations.
Mucus, secreted by mantle glands (Prezant, 1979),
forms a tight web along the radial striations (Fig.
2) and is further entangled by the small spines.

The exceedingly small spinules are truncated at
their tips (Figs. 3 and 4), and average 5.5 ycm in
height and 7.5 \xm in width at their base in a

94 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

bivalve 14 mm limK. The base of each spinule is
sunken into a slight depression of the underlying
supporting shell (Fig. 3). The spinules, which are
highly regimented in distribution (Fig. 5), aver-
age a distance of 15 i/m from one to another in
either direction. In the Cloroxed specimen (Fig.
6), the spinules have been partially dissolved,
especially peripherally suggesting an organic
component. The surface of the periostracum in
the treated specimen appears pitted (Fig. 6).
Treatment in dilute hydrochloric acid further
reduces the spinules, suggesting a calcareous por-
tion. The latter occurs primarily in the central
region of the spinule. This may indicate that the
spinule is composed principally of an aragonitic
core surrounded by periostracum.

Adhesion of foreign particles to the shell is
aided by the large number of truncated spinules
which help entangle the mucoid secretion
generated by the mantle glands. The viscous
mucus is laid down above, but in conjunction
with, the periostracum.

Discussion

Unlike the spinules of Laternula flexuosa,
another member of the Pandoracea, those of Li/on-
siu are not "prefabricated" in the mantle (Aller,
1974), but are laid down along with the rather
thin periostracum. This being the case, the spi-
nules are calcified periostracal components as
defined recently by Carter (1978). Allen and
Turner (1974) discussed several Verticordiids
possessing mantle glands, which attach sediment
to their shells, and have calcareous spinules
which may be preformed. Aller (1974) considered
attachment of external particles to the shell a
supplementation, using "prefabricated" ex-
traneous components in place of naturally
"prefabricated" spines. The latter author viewed
such supplementation, whether foreign or

natural, as a consistent theme within the Pan-
doracea.

The external adhesive properties of valves of
most Lyonsiids produces greater surface re-
sistance through attachment of sand grains, and
thereby greater stability within the substratum.
TTie sand cover of Lyomna hyalinn. and most like-
ly all other species of Lyonsia, may act secondari-
ly as an armor protecting the thin shell, and sedi-
ment adhering around the otherwise exposed si-
phonal region may act as a defensive barrier or
camouflage.

ACKNOWLEDGMENTS

I wish to thank Dr. M. R. Carriker for reading
the manuscript, G. T. Entrot for help with the
scanning electron microscope and P. Savage for
tj-ping the manuscript.

LITERATURE CITED

Allen, J. A. and J. F. Turner. 1974. On the functional mor-
phology of the family Verticordiidae (Bivalvia) with
descriptions of new species from the abyssal Atlantic. Phil.
Trans. R,ni. Sm:: London R 268: 401-.5.%.

Aller, R. C. 1974. Prefabrication of shell ornamentation in the
bivalve Laternula. Lethaia 7: 43-56.

Carter, J. G. 1978. Ecology and Evolution of the
Gastrochaenacea (Mollusca; BivalVia) with Notes of the
Evolution of the Endolithic Habitat. B>dl. Peabody Mux.
Nat.Hkt.il: 1-92. 67 figs.

Emerson. B. and M. K. Jacobson. 1976. American Museum of
Natural History Guide to Shells. A. A. Knopf Inc., N.Y., 482
pp.

Morris. P. A. 1973. A Field Guide to Sheik of the Atlantic
and Chdf Coasts and the West Indies. H. Mifflin Co., Boston,
330 pp.

Prezant, R. S. 1979. The structure and function of the radial
mantle glands of Lyonsia hyalina (Bivalia: Anomal-
odesmata). ./m/r Zool. London 187: In Press,

Yonge, C. M. 1952. Structure and adaptation in Lntodeitma
sarifola (Baird) and Mytilimpria nuttatlii Conrad - with a
discussion on evolution within the family Lyonsiidae
(P^ulamellibranchia). Univ. Cal. Pub. Zool. 55: 439-450.

FIGS. 1-6. 1, Surface vieiv of a partially cleaned shell o/ Lyonsia hyalina. Several sand grains remain adhered to the mucoid
coat which covers much of the periostracum. The prominent radial striations of the periostracum and the xmall spinules which
run parallel to them are evident. 75X. 2, Magnified view of the strand4ike mucoid secretion which ftmns a webbed pattern
along the radial striations of the periostracum. 6iOX. 3, A fi-actured section through the shell ofh. hyalina revealing the trun-
cated nature of the /leriostmcal spinules. The underlying nacre and tnyostracum are also ei-ident. 760X. 4, Magnified view of a
fractured spinule showing its confluence with the periosttrwum. .VCK)X. 5, An oblique surface view of the periostracum showing
alignment of the spinules. KXlflX. 6, FolUnring treatment in sodium hypochlorite the xpinules were dissolved revealing their
organic nature. This micrograph also shows the pitted outer surface of the shell after removal of the m ucoid coat. 1200X.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 95

l-'^*s^.

Sb^ |m^ :V i

Explanation ov (iippimtr page (Shell Spinules of the Bivalve. Lyonsia hyalina)

96 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

A BIOGRAPHY OF ANDREW GARRETT. EARLY NATURALIST OF POLYNESIA: PART 2*
CATALOGUE OF MOLLUSCAN SPECIES AND BIBUOGRAPHY

William J. Clench

Honorary Curator of Malacology
Museum of Comparative Zoology
Cambridge, Massachusetts 02138

The Andrew Garrett Shell Collection

The Garrett collection of land and marine shells,
together with Garrett's conchological library and a
few manuscripts, but not his journal, were pur-
chased by the Bishop Museum in Honolulu, Hawaii,
some time prior to 1899. Exact data concerning this
purchase are lacking. Apparently, the items were
not in the museum in 1893, when the natural his-
tory portion of the "Preliminary catalogue" was
printed, for under marine shells only the Baldwin
collection and some specimens from the Govern-
ment Collection were mentioned, but they may
have arrived a year or more before 1899, when the
first mention of the collection is made in printed
records of the museum. Dr. Wm. T. Brigham had
had time to have the specimens mounted on paste-
board blocks and labels printed before then.

In the Spring of 1899, Dr. Wm. H. Dall, of the U.
S. National Museum, was employed by the Museum
Trustees, upon recommendation of the Director
(Dr. Brigham) to come to the Bishop Museum and
examine the collection. He arrived August 16, and
spent two months making his study and correcting
the nomenclature. His report is published in the
Report of the Director for 1899 (Occasional Papers,
1(2): 10-13). Dall estimated that the collection con-
tained about 25,000 specimens, representing be-
tween 8,000 and 9,000 species, about one-fourth of
them land shells, all neatly mounted and with
printed labels, and largely with localities, at least
to island groups.

Andrew Garrett's shell collection was one of the
most romplete for Pacific areas of that period. It
formed the basis for many early descriptions of
species, and contains a number of type specimens
or at least cotype or paratype specimens of species
described by W. Harper Pease and other con-
chologists of the period. Dr. Dall states that he
simply "corrected" the names of the specimens.

It is unfortunate that we do not have more exact
information concerning the acquisition of these

'Part 1 on the life of (larrett. by W. Stephen Thomas, appeared
in the previous number of The Nnntilnx. vol. 93. no. 1. pp. 1.5-28.

early collections. For reasons best knovra to
himself. Dr. Brigham made only meager record of
early accessions. A search of Trustees records was
made by Dr. Yoshio Kondo at the time he wrote a
memorial to Dr. C. Montague Cooke, Jr., and he
states that he found no information concerning the
purchase of the Garrett (Ibllection.

Prepared by E. H. Bryan, Jr.

History of the Andrew Garrett Collection

1888-1972

Andrew Garrett died in Huahine, Society Islands,
Nov. 1, 1887. His private collection of shells went
on sale.

February 18, 1893: Charles R. Bishop, in Wash-
ington, D.C., wrote to Trustee Hyde [Bishop
Estate Letters in. Book 4, pp. 56-58], notifying
him that he had "authorized Mr. Dorence At-
water to buy the Garrat [sic] collection of shells
etc. at $5,000 if found to be in good order and
complete . . ."

May-October, 1893: Andrew Garrett collection
received by the Bishop Museum. This date is
deduced from Brigham 's correspondence between
March and December, 1893, listing the Museum's
needs to the Trustees.

1894-1899: Collection was catalogued by Brigham
(1894) and specimens were mounted, vnth
printed labels, on cardboard.

August, 1899: Wm H. Dall studied A. Garrett col-
lection. See BPBM Director's Annual Report for
1899 (Occas. Papers 1(2): 10-13).

1900 ff.: Garrett collection was in the [exhibit]
cases of BPBM (Director's Annual Report for
1900, p. 8; "A Handbook for Visitors . . ." by
Brigham, 1903).

1905: Garrett Collection was partly relabelled in
accordance with Dr. Dall's identification, and
was rearranged to accord with the new system of
taxonomic arrangement. (Director's Report for
1905, p. 260).

Vol. 93 (2-3)

April 23. 1979

THE NAUTILUS 97

1927: Garrett's land Shells were removed from the
showcases in Pobnesian Hall to the [Malacologj]
laboraton,'. (C. M. Cooke, Jr., annual report to
Director for 1927).

1930: Mrs. J. G. McAllister copied "Garrett's
original catalog into the Museum catalog . . ." (C.
M. Cooke, Jr., Annual Report for 1930). [Mrs.
McAllister did not, however, number the
specimens with the corresponding catalog
numbers; catalog numbers are 01-8694.]

1930-1970: Garrett's specimens were rearranged,
re-identified, re-surveyed, re-exhibited, etc., by
various workers in malacology.

1972 onward: Attempts are being made to locate
possible types and to designate them as lec-
tot\-pes by A. Kay and D. Fellows. We also hope
to completely determine the circumstances by
which the Museum acquired the collection.

Prepared by: Danielle B. Fellows
11 December 1972

Geographic Names

All of the type localities of Andrew Garrett
were given along with the original descriptions.
Certain of these names have changed with the
passage of time and are listed below:

Austral Islands are now Tubuai Islands.

Cook's Islands are now Cook Islands.

Kiva — This locality in the Fiji Islands has not
been located. It has been suggested that this
name may have been an error for "Kioa", a
small island at the eastern end of Vanua
Le\ai and northwest of Taviuni but Garrett
had mentioned this locality several times as
"Kioa shore reefe". It is possible that the
name Kiva has since disappeared. The name
Kiuva or Kiura has been suggested as well
(about central on the coast at the eastern end
of Viti Levu).

Paumotu, Panmotu and Paumotus Seas or Is-
lands are now Tuamotu Islands.

Tivinni — is Taviuni or Taveuni Island.

Viti Islands are Fiji Islands.

Abbreviations

AJC — American Journal of Conchology
ANSP — Academy of Natural Sciences of Phil-
adelphia

BPBM — Bernice P. Bishop Museum

BSMF — Bulletin Society Malac. France

JANSP — Journal Academy Natural Sciences
Philadelphia

JC — Journal of Conchology

PANSP — Proceedings Academy Natural Sci-
ences Philadelphia

PCANS — Proceedings California Academy Nat-
ural Sciences

PCAS — Proceedings California Academy Sci-
ences

PZS — Proceedings Zoological Society London

Garrett included several manuscript names of
W. H. Pease in the synonymy of other species by
Pease. In a few cases, Garrett described the
species with the original names. The credit for
these species go to Garrett as he described them
as well as added the figures.

Pease, like many others during these early
years of descriptive zoology, sent as gifts or ex-
change a great deal of material with manuscript
names, much of which was never described. Spec-
imens under these names are in many institu-
tions, both here and abroad, and Garrett's work
will have solved many of these nomenclature
problems for future workers.

abbreriata. Cithara. 1873, PANSP. p. 223. pi. 3, fig. 41

(Paumotus Isles).
acuticostata, "Mousson" Garrett, Partula, 1884. JANSP, (2)

9:30, pi. 2, fig. 13 a-b (Raiatea Island. Society Islands).
adusta. Partula. 1884, JANSP, (2) 9:79 [A manuscript name in

the sjTionymy of Partula varia Broderip.]
affinis. Gibbida, 1872, PCAS, 4:201. (Viti and Samoa Islands).
affinis. Nanina. 1887, BSMF, 4:4 [nomen nudum], (Isle

Faiwata, Marquises at 2000 feet). [Is Microcystis subvenosa

Ancey.]
affims. Rissoina. 1873. PANSP, p. 212, pi. 2, fig. 10 (Viti Isles).
affims. Tomatellina. 1879, PANSP, p. 23. [not fig.] (Rurutu

Id., Austral Islands).
dbopmKtatm, Goniobranchns. 1879. PANSP, p. 31. (Huahine,

Society Islands). [Is Glossodoris Ehrenberg 1831.]
altemata. Engina. 1872, PCAS. 4:203. (Samoa and Viti

Islands).
amanda. Odostomia. 1873, PANSP, p. 225, pi. 3, fig. 47, (Viti

Islands).
anceyana. Pitys. 1887, BSMF, 4:19, (I. le Dominique, Isles

Marquises). [F^tys Beck 1837, [nomen nudum] ], is Diaglyp-

tus Pilsbry 1893.
angustivolata. Microcystis. 1884. JANSP, (2) 9:20, pi. 2, fig. 34,

a-b. (Moorea Island. Society Islands).

98 THE NAUTILUS

April 23, 1979

Vol. 93 (2-3)

anthmciria. Nassa, 1873, PANSP, p. 229. pi. 3, fig. 57, (Viti

Isles).
(Ltsavaeturis, Nanina. 1887, PZS, p. 169, (Naviti Island, Assawa

Group, Viti Islands).
assimilis. Mitra. 1873, PZS, p. 841 [not fig.] (Rarotonga,

Samoa, and Viti Islands).
assimilL% Trachomorpha. 1884, JANSP, (2) 9:27, pi. 3, fig. 44

(Huahine Island, Society Islands).
avenacea. Tnmcatella, 1887, PZS. p. 301 [not fig.] (Vanua

Levu [Island], Viti Islands).
hiaihr. Prirtula. 1884, JANSP. (2) 9:79, [A manuscript name

in the synonymy oiPartula varia Broderip].
bicoUrr. Tiimada. 1880, JC. 3:38, [not fig.) (Samoa and

Paumotu Islands).
boraborensts. Pitys. 1884, .JANSP, (2) 9:32, pi. 2, fig. 18. a-b,

(Borabora Island. Society Islands).
bythineUaefirnnis. Atmpis. 1884, JANSP. (2) 9:98. pi. 3, fig. 73,

(Tahiti and Moorea Islands, Society Islands).
bythinaeformis. "Mirussim" Garrett, Omphalotropis. 1887. PZS,
p. 310 [not fig.] (Vanua Balavo, Windward Islands, Viti
Islands).
caelata, Oathurella, 1873, PANSP, p. 220. pi. Z fig. .34. (Viti

Isles).
caelata, Vitrinella, 1873, PANSP, p. 214, pi. 2, fig. 16, (Kiva

Island. Viti Isles).
canalis, Pitys. 1872, AJC, 7:227. pi. 19, fig. 17, (Rarotonga

Island. Cook's Isles). Lectotype (by Solem) in ANSP 477.52.
cmtanea. Turricula, 1880, JC, 3:42, [not fig.] (Samoa and Viti

Islands).
cavemula, Pitys. 1872, AJC, 7:226, pi. 19, fig. 16 (Rarotonga
Id., Cook's Isles [Cook Ids.] ). [Tryon had changed this name
to Helix mbcavemuLa in error — non cavemula Hombron
and Jacquinot 1841; Garrett had described his species in the
genus Pitys and not Helix.]
cnmanguineiis, Melampm. 1887. PZS, p. 287 [not fig.] (Vanua

Levu Island, Viti Islands).
consubrina, Pitys, 1884, JANSP, (2) 9:31, pi. 2, fig. 17. a-c

(Huahine Island, Society Islands).
consobrina, Plecotrema, 1873. PANSP, p. 236, pi. 3, fig. 69,

(Viti Isles).
ccmtigua. Microcystis. 1887, BSMF, 4:6 (lile Dominique, Isles

Marquises).
costata, Adf-nrhis, 1856 [1857], PCANS, 1:103 (Hawaii (Island],

Hawaiian Islands).
costatogranosa, Rissoim, 1873, PANSP. p. 211. pi. 2. fig. 7.

(Viti Islands).
costulatum. Caecum, 1873, PZS, p. 789. (Kioa Island. Viti

Islands).
crassilabrum, Rulimus. 1872, AJC, 7:233, pi. 18, fig. 5, (Vanua

Levu Id. Viti Isles).
craxsilabrum. Rissoa, 1856 [1857], PCANS, 1:102 [not fig.]

(Hilo, Hawaii Id., Hawaiian Islands).
erebristriaXuii. Melampus, 1887, PZS, p. 289 [not fig.] (north

coast of Vanua Levu [Island], Viti Islands).
erenilahrix. Cheletrnpi,% 1873, PANSP. p. 215, pi. 2, fig. 18,
(Paumotus Islands). [Tryon puts Cheletropis in the
synonomy of Sinuxiijern d'Orb. The.se are pelagic larvae of a
marine gastropod. Garrett's figure, however, does not show
any outer lip embayments. [WJC].

cretacea. Endndmta. 1884. JANSP. (2) 9:41. pi. 2. fig. 27, a-b

(Borabora Island, Society Islands).
crispa, Mitra (CosteUaria). 1872, PCANS, 4:201 (Samoa and

Viti Islands).
crystallim, Odostmnia. 1873, PANSP, p. 226, pi. a fig. 49 (Viti

Isles).
crystallina, ?Rissoa, 1873, PANSP. p. 216, pi. 2. fig. 24 (Kiva

Island, Viti Isles).
curta, Chnphalotropis, 1879, PANSP, p. 28, [not fig.] (Rurutu

Id.. Austral Islands).
cuspidata, Odustomia, 1873, PANSP, p. 228. pi. 3. fig. 54 (Viti

Isles).
daedalea. Oathurella, 1873. PANSP, p. 219. pi. 2. fig. .33 (Viti

Isles).
debilh Rissoim, 1873, PANSP. p. 212, pi. 2. fig. 9 (Viti Isles).
decorticata, Pitys, 1872, AJC, 7:228. pi. 19. fig. 19 (Rarotonga

Id., C<»k's Isles. [Cook Ids.]). Lectotj'pe (by Solem) in

ANSP 477.54.
degagei. Pttys, 1879, PANSP. p. 18 [not fig.] (Rurutu Id..

Austral Islands).
degagei, Succinea, 1879, PANSP. p. 26 [not fig.] (Rurutu Id.,

Austral Islands).
denseco,stata, Odostomia, 1873, PANSP, p. 223, pi. 3, fig. 42

(Samoa and Viti Isles).
densestnata. Odostomia. 1873, PANSP, p. 224, pi. 3. fig. 44

(Viti Isles and Samoa).
discoidiae. Microcystis. 1881, JANSP, (2) 8:409 [error for M.

discordice Garrett].
discorxiice. Microcystis, 1881, JANSP, (2) 8:383 [not fig.]

(Cook's Islands).
ebumea, Mitra, 1880, JC, 3:15 [not fig.] (Paumotu Islands).
ebumostoma, Mitra. 1880. JC, 3:1.5. [not fig.] (Paumotu

Islands).
erigua, Murex. 1856 [1857], PCANS, 1:102 [not fig] (Pure-
shallow P<x)ls: on the rock>- coasts of Hawaii).
exqvidta, Thahu 1872, PCANS, 4:202 [not fig.], (Paumotu

Islands).
exquisita, Mitra, 1872 [April 1893). PZS. p. 842 [not fig.],

(Paumotu, Tahiti. Cook's Islands. Samoa and Viti Islands).
eiilis, Odostomia 1873, PANSP. p. 223, pi. 3. fig. 43 (Viti

Isles).
fenestrata. FwsureUa 187a PCANS, 4:'204 [not fig.], (Viti and

Samoa Lslands).

festiva, Turricula 1880, JC, 3:46 [not fig.] (Viti klands).

ficta Endodfinta. 1884, JANSP. (2) 9:41 [Nomen nudum,
originally listed in the Schmeltz. Cat. Mus. Godeffroy 5:223
and renamed £! cretacea Garrett, q.v.]

filaris. Cmdhanus, 1872, PCANS, 4:202 [not fig.], (Samoa and

Viti Islands).
J}ericostata, Turricula, 1880, JC, 3:46 [not fig] (Paumotu and

Viti Islands).
foveolata. PissureUa, 1872, PCANS, 4:203 [not fig.] (Viti and

Samoa Islands).

'Pure may have meant Puna but the word in Hawaii;ui does not
mean "shallow pools". Data from Dr. Lee Moettler of the B. P.
Bishop Museum.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 99

fraiemda, Mitra. 1872, [April, 1873], PZS, p. 842 [not fig.]

(Tahiti, Rarotonga, Samoa and Viti Islands).
fiiscmigra, Turricula, 1880, JC, 3:47 [not fig.] (Kioa shore

reefs, Viti Islands).
fitsifimnis. Daphnella. 1873, PANSP, p. 229, pi. 3, fig. 58

(Paumotus Isles).
gibbosa. Engma. 1872, PCANS, 4:203 (Viti and Samoa

Islands).
godeffroyana, Nanina, 1872, AJC, 7:223, pi. 19, fig. 9 (Interior

of the N. E. part of Vanna Levu, Viti Isles).
geomeaensis. Heiicina, 1893, PANSP, p. 233, pi. 3, fig. 63

(Gomea Island, Viti Isles).
gracilis. Rissoina. 1873, PANSP, p. 211. pi. 2, fig. 8 (Viti and

Society Isles).
granum. Truncatella. 1872, AJC, 7:225 [not fig.] (N. E. end of

Tavinni Id., Viti Isles).
gregana. Libera. 1884. JANSP, (2) 9:136, pi. 2, fig. 6, a-b

(Moorea Island. Society Islands).
guanensis. Bulimus, 1872, AJC, 7:235, pi. 18, fig. 8 (Guan Isl.,

Viti Isles).
gummea. Trochonanina, 1887, BSMF, 4:14 (lile Nuka-Hiva,

lies Marquesas).
han-eyensis. Pitys. 1872, AJC, 7:228, pi. 19, fig. 20 (Rarotonga

Id., Cook's Isles [Cook Ids.]). Lectotype (by Solem) in

ANSP 477.56.
hirsuta. Plecotrema. 1872, AJC, 7:219, pi. 19, fig. 2 (Viti

Islands).
holosericea, Neritina. 1872, AJC, 7:219, pi. 19, fig. 1 (Vanna

Lavu, Viti Islands).
horrida. Rissoina. 1873, PANSP, p. 210, pi. 2, fig. 5 (Viti

Islands).
hoyti. Bulimus. 1872, AJC, 7:234, pi. 18, fig. 7 (Vanna Levu

Id.. Viti Isles).
hoyti. Nanina, 1872, AJC, 7:221, pi. 19, fig. 6 (Tavinni Id., Viti

isles).
hoyti. Tumcida, 1880, JC, 3:47 [not fig.] (Viti Islands).
huaheinensis. Partida, 1884, JANSP, (2) 9:78 [A manuscript

name in the synonymy ofPartula varia Broderip].
humeralis. Mitra, 1880, .JC, 3:18 [not fig.] (Anaa Island,

Paumotu Islands).
hyaixna. missoa. 1873, PANSP, p. 217, pi. 2, fig. 25 (Samoa,

Viti and Paumotus Isles).
hyaliniis. Obeliscus. 1893, PANSP, p. 228, pi. 3, fig. .56

(Paumotus and Society Isles).
imperfirrata. "Pease" Garrett. Partida. 1884, JANSP, (2) 9:.54,

pi. .3, fig. 53 (Toloa and Hapai Valleys, west coast of Raiatea

[Island] Society Islands).
indsa, Tarricula, 1880. JC, 3:63 [not fig.] (Kioa shore reefs,

Viti Islands).
incisus. Melampus. 1887, PZS, p. 289 [not fig.] (Vanua Levu

[Island] Viti Islands).
iilfrastncta Rissoa, 1873, PANSP, p. 215. pi. 2, fig. 21 (Kiva

Island, Viti Isles).
injrasulmta. CMhurella. 1873, PANSP, p. 220, pi. 2, fig. 35

(Viti Isles).
instricta, Turricula, 1880, JC, 3:48 [not fig.] (Viti Islands).
irregularis. Patula, 1887, PZS, p. 179 [not fig.] (Viti Levu, Viti

Islands). Lectotype (by Solem) in BPBM 7982.

kantavuenxis, Trochomarpha, 1887, PZS, p. 177 [not fig.] (Kan-

tava Island, Viti Islands).
kivaensis. Nanina, 1873, PANSP. p. 237, pi. 3, fig. 71 (Kiva

Island, Viti Lsles).
koroensis. Bulimus. 1872, AJC, 7:236, pi. 18, fig. 9 (Koro Isl.,

Viti Isles).
laeiicostata, Tiirricula, 1880, JC, 3:50 [not fig.] (Paumotu

Islands).
lamellwosta, Patula, 1884, JANSP, (2) 9:30, pi. 2, fig. 11, a-b

(Tahiti Island, Society Islands). Lectotype (by Solem) BPBM

2841.
lento, Microcysti'!, 1887, BSMF, 4:5 (I. le Dominique, I. les

Marquises).
laynrdiana. Oniphalotropis. 1887, PZS, p. 310 [not fig.] (Vanua

Balavo [Mbalavu], Windward Islands [Fiji Islands] ).
lentiginnsa. Pythia, 1872, AJC, 7:220, pi. 19, fig. 4 (Tavinni Id.

Viti Isles).
Libera 1881, JANSP, (2) 8:.390 [no type species indicated].
liricincta, Vitnnella. 1873, PANSP, p. 213, pi. 2, fig. 14 (Kiva

Island, Viti Isles).
littarinaeformis, ?Rissoa 1873, PANSP, p. 215, pi. 2, fig. 18

(Kiva Island, Viti Isles).
lutea, Odostomia. 1873, PANSP, p. 226, pi. 3, fig. .50 (Viti

Isles).
luteofusca, Mitra, 1872 [1873], PZS, p. 842 [not fig.]

(Rarotonga, Cook's Islands).
marquesana, Pitys, 1887, BSMF, 4:18 [not fig.] (Nuka-Hiva, I.

les Marquesas).
marqiiesana, Suecirwa, 1887, BSMF, 4::B7 [not fig.] (I. le

Dominique, I. les Marqueses).
maupiensis, Pitys, 1872, PCAS, 4:204 [not fig.] (Mautipi

Island, Society Islands).
maupiensis. Pitys, 1873, PANSP, p. 233, pi. 3, fig. 64 (Maupiti

Island, Society Isles).
melanostoma, Cithara, 1873, PANSP, p. 222, pi. 2, fig. 40 (Kiva

Island, Viti Isles).
rnelanostoma, Persa. 1872, AJC, 7:224, pi. 19, fig. 11 fV'iti

Isles).
merzianoides. Helix (Trochomarpha), 1872, PANSP, p. 237, pi.

3, fig. 72 (Vanna Levu Island, Viti Isles).
micans, Tcimatellina. 1879, PANSP, p. 23 [not fig.] (Rurutu

Id., Austral Islands).
milleciistata Rissoina, 1873, PANSP, p. 210, pi. 2, fig. 3 (Viti

Islands).
mdlegrana Daphnella, 1873, PANSP, p. 230, pi. 3, fig. .59

(Paumotus Isles).
miruyr, Hipponix (Amalthea). 1856 [18.57], PCANS, 1:103 [not

fig.] (Hawaii [Island], Hawaiian Islands).
minutissima. DriUia, 1873, PANSP, p. 218, pi. 2, fig. .30 (Viti

Isles.)
modicella, Turricula, 1880, JC, 3:53 [not fig.] (Paumotu

Islands).
monticola, Heiicina, 1887, BSMF, 4:42 (I. le Dominique, I. les

Marqueses). [Nomen nudum, \s Heiicina versihs Ancey]
mooreana, Zonites, 1884, JANSP, (2) 9:23, pi. 2, fig. 28, a-b

(Moorea Island, Society Islands).
midticostata, Rissoa, 1856 [1857], PCANS, 1:103 [not fig.]

(Hilo, Hawaii Id., Hawaiian Islands).

100 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

mulHlamMata. Pitys. 1872. AJC. 7:230. pi. 19, fig. 2.5

(Rarotonpa Id.. Cook's Isles [Cook Ids] ).
muHUuieata, Turbo. 18.56 [1857], PCANS, 1:102. [not fit;.]

(Hilo Bay. Hawaii Id.. Hawaiian Islands).
multistriata, \anina. 1887. RSMF, 4:12 (I. le Taiwata. I. les

Marqueses). [Nomen nudum]
newcombittnum. Succinea. 1^56 [1857]. PCANS. 1:103 [not fig.]

(Disctrict of Waimea [Oahu Id.] Hawaiian Islands).
nigricans, Turricula, 1880. JC, 3:47 [Nomen nudum, is Tur-

riculafusconigra Garrett.]
nodosa. Vitrinetla. 1873. PANSP, p. 214. pi. 2. fig. 17 (Viti

Isles).
obeliicus, Odostomia. 1873. PANSP, p. 226, pi. 3, fig. 51 (Viti

Isles).
obesa. Atropis. 1884, JANSP, (2) 9:99, pi. 3. fig. 72 (northwest

part of Tahiti [Island]. Society Islands).
obesa, Claihimlla, 1873. PANSP, p. 221. pi. 2. fig. ;36 (Viti

Isles).
ochrostnma, Bulirmis. 1872. AJC. 7:232. pi. 18, fig. 3 (Tavinni

Island. Viti Islands).
octolamellata. Pttys. 1887, BSMF, 4:18 [not fig.] (I. le Domini-
que, I. les Marqueses).
(rryza. Odostomia, 1873, PANSP, p. 224, pi. 3, fig. 45 (Kiva

Island, Viti Isles).
oryza. RissuiTia, 1873, PANSP, p. 210. pi. Z fig. 4 (Kiva Island.

Viti Islands).
otareae. Nanina, 1872, AJC, 7:222, pi. 19, fig. 8 (Natawa Bay,

Vanna Levu [Fiji Islands]).
otareae. Pitys. 1872, AJC, 7:228, pi. 19, fig. 21 (Rarotonga Id..

Cook's Isles [Cook Ids.] ). Lectotype (by Solem) ANSP 477.55.
paliuiosu.% Ophicardelus. 1872. AJC, 7:220, pi. 19, fig. 3 (Viti

Islands).
papilla<<a. [Mllia. 1873, PANSP, p. 218, pi. 2, fig. 29 (Viti

Islands).
paumotuensis. Sciss^irella, 1873, PZS. p. 878 [not fig.]

(Paumotu Islands).
peaseana, Tomatellina, 1884. JANSP. (2) 9:83. pi. 2. fig. 19

(Moorea Island. Society Islands).
jjenseii, Dirricnln. 1880..JC.3:.57 [not fig.] (Viti Islands).
periivata, Pythm. 1872, AJC, 7:221, pi. 19, fig. 5 (Viti Isles).
perpiexa. Partida. 1884, JANSP, (2) 9:79. [Nomen nudum, in

the synonymy of Partida varia Broderip, in Garrett.]
perpiexa. Tomatellina, 1879, PANSP, p. 24 [not fig.] (Rurutu

Id., Austral Islands).
pieea, Endodonta fabrefacta var., 1884, JA.NSP, (2) 9:39, [not

fig.) (W. side of Raiatea Island, Society Is ands).
picturata. Nai-u-ella. 1872, AJC, 7:224, pi. 19, fig. 13 (Vanna

Levu, Viti Isles).
pirujtm. Ckithurella. 187.3, PANSP, p. 221, pi. 2, fig. 38 (Samoa

and Viti Isles).
pimjuix. Partida. 1884, JANSP, (2) 9:77 [not fig.] (mountain

ravines at the head of Vaioara Valley, Raiatea Id., Society

Islands). ["It certainly = rustica" [Garrett]. A manascript

name in the synonymy of Partula rustica Pease.]
planoconiut 'Mousson' Garrett. Trochomorpha, 1887. PZS, p.
174 (Ono Island, Viti Islands). [This was a ms. name by
Mousson, which Garrett described.]
plano.fpira, Patula. JANSP. (2) 8:388 [not fig.] (Rarotonga
Island. ('<K)k's Islands). Lectotype (by Solem) in Zool. Mus.
Univ. Zurich.

pfMiana. Helicina. 1887. PZS. p. 313 [not fig] (Viti Levu [Fiji

Islands]).
praj!ina. Gibbxda, 187^ PCANS. 4:202 [not fig.] (Viti Islands).
proputqua. Mitra, 1880. JC. 3:22 [not fig.] (Society Islands).
propinqua. Turricula, 1880. JC. 3:58 [not fig.] (Viti Islands).
prorima, Pitys. 1872. AJC. 7:230. pi. 19. fig. 21 (Rarotonga Id..

Cook's Isles [Cook Ids] ). Lectotype (by Solem) in ANSP

47700.
pulchra. OdostomicL, 1873. PANSP. p. 225, pi. 3, fig. 48 (Viti

Isles),
pulchra. Turricula. 1880, JC, 3:56 [not fig.] (Viti and Samoa

Islands).
pidchella, Clathurella, 1873, PANSP, p. 219, pi. 2, fig. 32 (Viti

Isles).
punctifera, Clathurella, 1873, PANSP, p. 222, pi. 2, fig. 39

(Society, Samoa and Viti Isles).
punctifera. Microcystis. 1879, PANSP. p. 17. [not fig.] (Rurutu

Id.. Austral Islands).
punctiperforata, Pitys. 1884. JANSP. (2) 9:.32. pi. 2, fig. 16. a-c

(Moorea Island. Society Islands).
pura. Microcystis. 1887. BSMF. 4:5 [not fig.] (I. le Dominique.

I. les Marqueses).
pura. Vitrinetla. 1873. PANSP. p. 213. pi. 2. fig. 13 (Kiva

Island, Viti Isles).
pusUla, Drillia. 1873, PANSP, p. 219. pi. 2. fig. 31 (Viti Isles,

Cook's Isles, Paumotus Isles).
pygmaea. Volvaria (Volvarina), 1873, PANSP, p. 217, pi. 2, fig.

27 (Viti Isles).
(juadricarinala, Separatista, 1873, PZS, p. 878 [not fig.]

(Paumotu Islands).
rad>ata Pease] PaHnia, 1884, JANSP, (2) 9:74, pi. 3. fig. 45

(Hamoa Valley, east coast of Raiatea Island, Society

Islands).
raiatensis. Helicina. 1884. JANSP. (2) 9:106. pi. .3. fig. 69. a-b

(Raiatea [Island]. Society Islands).
1-aiatensis. Partula, 1884. JANSP. (2) 9:54. [Nomen nudum, in

the synonymy of Partida imperforata "Pease" Garrett . q.v.]
rambiensis. Bulimus. 1872. AJC. 7:233. pi. 18. fig. 4 (Rambi

Id.. Viti Isles).
recedens. Libera. 1884. JANSP. (2) 9:36. pi. 2. fig. 7 (Moorea

Island. Society Islands).
reticulata, Pleurotoma (Mangelia). 1856 [1857], PCANS, 1:102

[not fig.] (Hilo Bay, Hawaii, Hawaiian Islands).
Rissopsis. 1873, PANSP, p. 228, type species Rissopsis typica

Garrett, (monotypic).
rudi.'i. Pitys. 1872. AJC. 7:227. pi. 19. fig. 18 (Rarotonga Id..

Cook's isles [Cook Ids.]). LectotjT)e (by Solem) in ANSP

47701.
riigatus. Bidiniiis. 1872. AJC. 7:234. pi. 18. fig. 6 (Vanna Levu

id..VitiLsles).
ran(0«7i.s-i.s'. Piitula. 1879, PANSP, p. 18 [not fig.] (Rurutu Id..

Austral Islands).
riLsticus. Melampii.':. 1887, PZS. p. 289 [not fig.] (Viti Islands

and on Tonga and Samoa Islands).
scaha, Ri.osoma, 1873. PANSP. vol. 25. p. 211. pi. 2. fig. 6 (Viti

Islands).
scatpta. Microcystis. 1884. JANSP. (2) 9:21. pi. 2. fig. 30. a-b

(TahiiJi Island. Society Islands).
.^rhmeltziann, Zoitites. 1887. PZS. p. 173 (Malolo Island. Viti

Islands). [Is in the genus (>rpiella.]

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 101

sa-ipta. Bulla, 1856 [1857]. PCANS, 1:103 [not fip.] (Hilo.

[Hawaii Id.]. Hawaiian Islands.)
sculptili'!. Rissmm. 1873, PANSP, p. 209, pi. 2, fig. 2 (Viti

Islands).
sculptUi.% Vitrinella. 1873, PANSP, p. 214, pi. 2, fig. 15 (north

coast of Natawa Bay, Vanna Levu, Viti Isles).
semilmeata. Oathurcllu. 1873, PANSP. p. 221, pi. 2, fig. 37

(Samoa and Viti Isles).
simidans. Helicim. 1884, JANSP, (2) 9:105, pi. 3. fig. 66, a-b

(Tahiti [Island], Society Islands).
spiripuncta, Mitra. 1880, JC, 3:27 [not fig.] (Koro reefs, Viti

Islands).
steamseayia. Microcystis. 1887, PZS, p. 171 [not fig.] (Viti

Islands).
stellaris. Separatista, 1873, PZS, p. 879, (Samoa and Viti

Islands).
striata. Gibbida, 1872, PCAS, 4:201 [not fig.] (Viti and Samoa

Islands).
striaiella. Purpitra. 1856, [1857], PCANS. 1:102 [not fig.]

(Island of Hawaii. Hawaiian Islands).
striatula, Trochus. (Mm-garita). 1856 [1857], PCANS. 1:102

(Hawaii [Island] Hawaiian Islands).
strict^is. "Mousson" Garrett. Ostodes. 1887, PZS, p. .306 [not

fig.] [See Clench 1949, B. P. Bishop Museum, Bull 196, p. 21,

fig. (Holotype 8a)]. (Vatu Lele Island, ex museum Godef-

froy) [Fiji Islands.]
subcomda. Trockonanina, 1887, BSMF. 4:13 (I. le Dominique, I.

lesMarqueses).
subexcrescens. Microcystis. 1881, JANSP, (2) 8:381, (Rarotonga,

Cook Islands). [Nomen nudum.]
sitbglobosa. Succinea, 1884, JANSP, (2) 9:88, pi. 2, fig. 3

(Tahiti [Island] Society Islands).
subghboxiis. Pedipes. 1873, PANSP, p. 236, pi. 3, fig. 70 (Tan-

thala Island, Viti Isles).
subntfa "Pease" Garrett. Helicina, 1884, JANSP, (2) 9:104, pi.

3, fig. 68, a-b (Raiatea and Borabora [Islands] Society

Islands).
subrugosa, Trochmumina, 1884, JANSP, (2) 9:22, pi. 2. fig. 38,

a-d (Tahiti and Moorea [Islands] ).
subtexturata, Mitra. 1880, JC, 3:26 [not fig.] (Raiatea Island,

Society Islands).
subtilis. Pitys. 1884, JANSP, (2) 9:31, pi. 2, fig. 15, a-c

(Huaheine Island, Society Islands).
s^dcata, Odostomia. 1873, PANSP, p. 224, pi. 3, fig. 46 (Viti

Isles).
supracostata, Rissoina, 1873, PANSP, p. 209, pi. 2, fig. 1 (Viti

Isles).
suturalis. "Pease" Garrett. Partula, 1884, JANSP, (2) 9:6.3, pi.

3, fig. 77 (Haamene Valley, east coast of Tahaa [Island],

Society Islands).
tahitensis. Mitra. 1880, JC. 3:30 [not fig.] (Tahiti Island, Socie-
ty Islands).
tahitemis. Trockonanina, 1884, JANSP, (2) 9:23, pi. 2, fig. 39,

a-c (Tahiti Island, Society Islands).
taneae. Pitys. 1872, PCAS, 4:204 [not fig.] (Maupiti Island,

Society Islands).
taneae. Pitys. 1873, PANSP, p. 234, pi. 3, fig. 65 (Maupiti

Island. Society Isles).
tainnnietisis. Helix. 1872, AJC, 7:223. pi. 19, fig. 10 (Tavinni

Id., Viti Isles).

tPtiella, Nanina. 1872, AJC, 7:222. pi. 19, fig. 7, (Kioa Id.. Viti

Isles).
tenuicostata, Pitys, 1872, AJC, 7:229. pi. 19, fig. 23 (Rarotonga

Id., Cook's Isles [Cook's Ids.] ). Lectotype (by Solem) in

ANSP47702.
terehra, Rissoina. 1873, PANSP, p. 212, pi. 2, fig. 11 (Viti and

Samoa Islands).
tessellata, Daphnella, 1873, PANSP, p. .330, pi. 3, fig. 61

(Paumotus Isles).
thdia, Partida. 1884, JANSP, (2) 9:69, pi. .3, fig. 46 (Huaru

Valley, west coast of Raiatea Island, Society Islands).
themis. Trcchomorpha. 1887, PZS, p. 177 (new name for

Trochornorpha ludersi Mousson 1870, non Pfeiffer 18.55).
trynni, Goniodaris. 1873, PANSP, p. 2.32. pi. 4 (Society Islands).
tntncata, Rissoa. 1873, PANSP, p. 217. pi. 2. fig. 26 (Kiva

Island, Viti Isles).
tumuloides, Pitys. 1872, AJC, 7:225, pi. 19, fig. 15, (Rarotonga

Id.. Cook's Isles [Cook Ids.] ).
turrita. Plecotrema, 1873. PANSP. p. 235. pi. 3, fig. 68 (N. E.

end of Tavinni [Taveuni Island] Viti Isles).
turrita. Rissmrm. 1873, PANSP, p. 213, pi. 2, fig. 12 (Society

Islands).
typica, Rissopsis. 1873, PANSP, p. 228, pi. 3, fig. .55 (Viti and

Samoa Isles).
unilamellata, Pitys. 1873, PANSP, p. 235. pi. 3. fig. 67

(Rarotonga Island, Cook's Isles).
unilineata. Odostomia. 1873, PANSP, p. 227, pi. 3, fig. .53 (Viti

Isles).
unilineata, Turricula, 1880, JC, 3:60 [not fig.] (Viti Islands).
ventricosa. Turricula, 1880, JC, 3:55 [not fig.] (Samoa and Viti

Islands), [Nomen nudum]. [Is T porphyretica Reeve.]
venusta, Rissoa, 1873, PANSP, p. 216, pi. 2, fig. 23 (Viti Isles).
vidmUndes. Drillm. 1873, PANSP, p. 217, pi. 2, fig. 28, (Viti

Isles).
riolacea. Thala. 1872, PCAS, 4:202 (Samoa and Viti Islands).
virginea, "Pease" Garrett, Partula, 1884, JANSP, (2) 9:61, pi.

3, fig. 54 (Vaipiti Valley, west coast of Tahaa [Island] Socie-
ty Islands).
vitiarm, Paludinella, 1872, AJC, 7:224. pi. 19, fig. 12 (Viti

Isles).
vitiense. Caecum, 1873, PZS, p. 879 (Kioa Island, Viti Islands).
vitiensis. Assiminea. 1872, AJC, 7:'225, pi. 19, fig. 14 (Viti

Isles).
intiensis, Placostylus, 1887, PZS, p. 184 [not fig.] (Na Viti

Levu Bay, N. E coast of Viti Levu, Viti Islands).
litiemis. Pupina. 1873, PANSP, p. 233, pi. 3, fig. 62 (Gomea

Island, Viti Isles).
ritrea. Daphnella, 1873, PANSP, p. 230, pi. 3, fig. 60

(Paumotus Isles).
vitrea, Odostomia. 1873, PANSP, p. 227, pi. 3, fig. 52 (Viti

Isles).
ritrea. ?Ri%'ioa. 1873, PANSP, p. 215, pi. 2, fig. 19 (Kiva Island,

Viti Isles).
woapoensis, Pitys, 1887, BSMF, 4:17, (1. le Woapo, I. les Mar-

queses).
youngi, Pitys, 1872, AJC, 7:229, pi. 19, fig. 22 (Rarotonga Id.,

Cook's Isles [Cook Ids.] ). Lectotype (by Solem) in ANSP

47703.
zebra. Strigatella. 1880. JC. 3:35 [not fig.] (Viti and Samoa

Islands).

102 THE NAUTILUS

April 23, 1979

Vol. 93 (2)

zehrina. Mitra. 1872 [187.3] PZS. p. »42, [not fig.] (Paumotu.

Tahiti. Cook's [Islands], Samoa. Viti Islands).
zebrina. Pitys. 1873. PANSP, p. 234, pi. .3. fig. 66 (Rarotonga

Island. Cook's Isles).

Additional Names by William Harper Pease

These names were inadvertently omitted by W.
J. Clench (1975), Nemouria, no. 16, Delaware
JMaseum of Natural History.

apprurinintn Pease. PiiriuUu 1884, .JANSP, (2) 9:7.5 [nomen
nudum]. [Is P. inttata Pea.se. It was listed earlier by Glo>Tie
in the Journal of Conchology. 1:338. May. 1878].

microsUima Pease, Partida. 1884, JANSP, (2) 9:74 [nomen
nudum]. [Is P. radiata "Pease" Garrett, lyr]

fraterntld Pease, Helix, 1867, AJC, 3:104. [New name for
Helix sadptilis Pease, 18&5, non Bland 1858.]

oimlaiifiixis "Pea.se" Tryon. Milmiiu. 18«i. A.JC. 2:299. pi. 2f),
fig. 4 (Oualan I. [now Kusaie Island. Caroline Islands.]). [A
manuscript name by Pease but never described by him.]

IMoIluscan Bibliography of Andrew Garrett

1856 [1857] "On New Species of Marine Shells of the Sand-
wich Islands." Pmc. California Acad. Nat. Sci.. 1:102-103.

1872 a. "Descriptions of New Species of Shells from the South
Sea Islands." Pmc. California Acad. Sci., 4:'201-204.

1872 b. "Descriptions of New Species of Land and Freshwater
Shells." ^IniCT-. J. Conch., 7:219-230. pi. 19.

1872 c. "List of Species of Bulimus Inhabiting the Vili
Islands, with Notes on Their Geographical Range, and
Descriptions of New Species." Amer. J. Conch. 7:231-236, pi.
18.

1873 a. "Descriptions of New Species of Marine Shells In-
habiting the South Sea Islands." Proc. Acad. Nat. Sci.
Philadelphia, pp. •2(J9-231. pi. 2-3.

1873 b. "Description of a New Species of Goniodoris." Proc.
Acad. Nat. Sci. Philadelphia, p. 232, pi. 4.

1872 [1873 c] "List of the Species of Mitridae Collected at
Rarotonga, Cook's Islands, with Notes, also with Descrip-
tions of New Species." Pmc. Zool. Soc. London, pp. 839-843.

1873 d. "Description of New Species of Land Shells Inhabiting
the South Sea Islands." Pmc. Acad. Nat. Sci. Philadelphia,
pp. 233-237, pi, 3.

1872 [1873 e.] "Description of a New Species of Scissurella

from the Paumotu Islands." Proc. Zool. Soc. London, pp.

878-879.
1872 [1873 f.] "Descriptions of Two New Species of Caecum

from the Viti Islands." Pmc. Zool. Soc. London, p. 879.
1872 [1873 g.] "Descriptions of Two New Species of

Separatista." Pmc. Zml. Soc. Limdon. p. 878 [Paumotu

Islands].
1878 a. "Occurrence of Gadinia reticulata Sow., in

Southeastern Polynesia."./, of Conch. 1:335.

1878 b. "Occurrence of Crepidula aeuleata Gmel., in the Mar-
queses Islands." J of Conch. 1:335-336.

1878 c. "Annotated Catalogue of the Species of Conus Col-
lected in the South Sea Islands." J. of Conch. l:3,53-.367.

1879 a. "List of I.and Shells Inhabiting Rurutu. one of the
Austral Islands, [Tabuai Ids.] with Remarks on Their
Synonymy, Geographical Range and Descriptions of New
Species." Proc. Acad. Nat. Sci. Philadelphia, pp. 17-30, [pp.
17-24, March 25, 1879; pp. 25-30, April 15, 1879].

1879 b. "Description of a New Species of Goniobranchus."
Proc. Acad. Nat. Sci. Philadelphia, p. 31.

1879 c. "Annotated Catalogue of the Species of Cypraeidae
Collected in the S. Sea Islands."./ of Conch., 2:105-128.

1880 "Catalogue of the Polynesian Mitridae, with Remarks on
Their Geographical Range, Station and Descriptions of Sup-
posed New Species." J. of Conch.. 3:1-7.3, [pp. 1-32, Jan.
1880; pp. 33-73, April 1880].

1881 "The Terrestrial Mollusca Inhabiting the Cook's or
Hervey Islands." Jour. Acad. Nai. Sci. Philadelphia, (2)
8::381-411.

1884 "The Terrestrial Mollusca Inhabiting the Society

Islands." .Jcmr. Acad. Nat. Sri. Philadelphia, (2) 9:17-114, pi.

2-3.
1887 a. "On the Terrestrial Mollusks of the Viti Islands. Part

I." Proc Zool. Soc. London, pp. 164-189 [June 1, 1887].
1887 b. "Mollusques Terrestres des lies Marquises." Bull. Soc.

Maine. France, 4:1-48.
1887 c. "On the Terrestrial Mollusks of the Viti Islands, Part

II." Proc. Zool. Soc. London, pp. 284-316 [Aug. 1. 1887].
1887 d. "The Terrestrial Mollusca Inhabiting the Samoa or

Navigator Islands." Proc. Acad. Not. Sri. PhiUidelphia,

39:124-1.53.

Acknowledgments

I wish to thank Mr. Edwin H. Bryan for data
on place names and for the history on the Andrew
Garrett Collection and to Danielle B. Fellows for
the chronological data on the collection. To Dr.
Yoshio Kondo for xerox copies about Andrew Gar-
rett held in the library of the Bemice B. Bishop
Museum. To Mary Anne Quilty, I am most grate-
ful for typing the manuscript and for several help-
ful suggestions.

My thanks are due to Dr. Joseph Rosewater of
the National Museum of Natural History for
checking the publications of Andrew Garrett in
the department of Mollusks.

Vol. 93 (2-3)

April 23, 1979

THE NAUTILUS 103

THE CAECIDAE (GASTROPODA: RISSOACEA)
OF WATER ISLAND, U. S. VIRGIN ISLANDS, WITH A NEW SPECIES.

Hugh J. Mitchell-Tapping'

Department of Geology

The Florida State University

Tallahassee, Florida 32306

ABSTRACT

Eleven shallow-icater species of C-decum, from the marine sediment aronnd Water
Island, are described according to their microsculpture as observed under the scan-
ning electron microscope. One new species, Caecum donmoorei. irhich was found in
Sprat Bay. Water Island. ?.s also described.

In 1973, a study was made of the shallow ma-
rine carbonate sediment around Water Island,
the fourth largest island in the U. S. Virgin Is-
lands group. A total of 56 samples of approxi-
mately 100 grams each was collected around the
island at sites which were exposed to differing
amounts of wave-energy. A total of 618 Caecidae
was picked from the samples and their distribu-
tion around the island was plotted according to
the number of specimens found (Fig. 1).

~-\

St. Thomas

/—^

;

/^

-■ .

-^^

Jy^

( ,— -V

s:^

N^

""-^ ( o \

\ o

.s^^

\ *^

/ \(

^

CROWN BAY

/ /\

\

II .10

/ / \

1

46jts

V*v«o

\ yv

( ^

-^ .^-

isl/

K

.7 -^ yh- \

V/

^^ 12./

.•**

y^\ \% \

^-~^

hA \ P- \

(

roe

1» •^

• 5 ?>

6 .6,

IV. <r .9

■o

1 5*]

.1 IJ

Vi4 o

10^
10.16^

5 ^" L

26?

9V^i>^

/

I9»

I7»"V^
ll» 50\.

1

O /•lo

' '

'T

/

T^^^^lf^^^

"k

^^•6 0

N

.5KM

I0«

• 5 SCALE

FIG. la. Ih.stnbutiim of the number of xpeciiiienn collected
around Water Island, U. S. Virgin Island-t. Stippled areas are
grassbed, low wave-energy areas.

•

y^ ^. i iMm

ffM al^^p&

(

• o • •

'Present address: 6101 Warwick Qiurt, New Orleans, La 70114.

FIGS. 1-8. 1, C. breve Foliii Xlo: 2, C. breve Folin X120:
3, C. imbrieatum Cm-penter X15; 4, C. imbricatum Carpenter
X120; 5, C. tenuicostatum Folin X^O; 6, C. tenuicostatum
Folin X215; 7, C. tenuicostatum Folin X1.5; 8, C. tenuicosta-
tum Folin XUO.

Compared with samples from Bahia Honda
in the Florida Keys, where up to 212 specimens
per sample occur, there are few specimens in this
area. This may be due to the geographical loca-
tion of the Virgin Islands and the prevailing east-
west current. This current results in the speci-
mens being representative of the local standing
crop only. It is interesting to note that not a sin-
gle specimen of Caecum in.sulanon Moore, origin-
ally found on the sister island of St. John (Moore,
1970), was present in Water Island samples.

104 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

^^^^^^?

4 ^^^^^^^^^^^v i^l^^^^^^^^^H

^^^

FIGS. 9-16. 9, C. regulare Carpenter X25: 10, C. regulare
Carpenter X175: 11, C. textile Fniin Xii5: 12, C. textile Folin
XSiO; 13, C. cornucopiae Carpenter X15; 14, C. comucopiae
Carpenter X2i0; 15, C. gurgulio Carpenter X20: 16, C. gur-
gulio Carpenter X160.

The distribution of the 618 specimens (Fig. 1)
shows no discriminate pattern, other than the
low count for the eastern side of the island. This
small number of specimens might be attributed
to the local water current through Gregerie
Channel, which would move the specimens to a
lower energy area. The dominant species in the
grass-beds, low-energy areas, were Caecum comu-
copiae Carpenter (Figs. 13 and 14) and C. mtidum
Stimpson. Distinguishing between these two
species is rather difficult, but C. nitidum tends
to be larger with a more oblique aperture in the
adult stage. The row of dark spots sometimes
seen on C. comucopiae by Moore (1972) was not
apparent in the specimens from the grassbeds
and only seen on two specimens from a reef area
in a southside bay. In the reef, or medium wave-
energy areas, the most abundant species was
C. regulare Carpenter (Figs. 25, 26, 27 and 28).
C. breve Folin (Figs. 1 and 2), C. lineicinctum
Folin (Figs. 31 and 32), and C. floHdanvm Stimp-
son (Figs. 19 and 20) were also found in these
areas. The dominant species in the rocky, high
wave-energy areas on the southern side of the

island was C. imbricatum Carpenter (Figs. 3 and
4). A rare species, C. tenuicostatum Folin (Figs.
5, 6, 7, 8, 23 and 24) was also found in these
areas. Some of the specimens of C. tenuicostatum
appear under the SEM to have longitudinal ribs
which are smoother and less raised on one side,
giving an appearance of wavelike ribs moving
clockwise looking down from the aperture.

One species common to all areas is C. textile
Folin (Figs. 11 and 12). Some specimens of C.
textile (Figs. 17 and 18) appear under the light
microsc-ope as having a raised interspace between
the annular ridges, giving an almost smooth ap-
pearance, while the SEM reveals that the longitu-
dinal striae on the ridges are continued through
the interspace and are joined to those on the
adjacent ridges (Fig. 18). Another species, also
common to all wave-energ>' environments, is C.
regulare Carpenter and its close relative, C.
gurgulio Carpenter (Figs. 15 and 16). The sculp-
ture of C. regulare, as revealed by the SEM,
shows an absence of striae between the well-
raised, flat-topped annular ridges (Fig. 26). This
can also be seen in the specimen described by

FIC.S. 17-24. 17, C. textile Fo/i« X.W, 18, C. textile /-"o/ih X^IO;
19, C. floridanum Stimiison X20: 20, C. floridanum Stimpsmt
X1J,'>: 21, C. (iimnicKirei h.s. jximlinx' XW: 22, C. donmoorei
n.x. iximtifiH' X1.',(K 23, ('. tenuicxistatum FuUn Second xtage
XJO: 24, C. tenuicostatum Falin X«ft

V(,1.9H(2-:?)

April 23, 1979

THE NAUTILUS 105

FIGS. 25-:32. 25, C. regulare Cm-pent er XIO; 26, C. regulare
Carpetiter X210: 27, C. regulare Carpenter Second staye plus
part of third staye XJS: 28, C. regulare Carpenter X175:
29, C. donirnwrei n.s. Imlotyije X20: 30, C. donmoorei n.s. ho-
kitifiw Xl'O; 31, C. lineicinctum Folin X20: 32, C. linei-
cinctum Folin XSO.

Moore (1972). C. gurgulio is very similar in ap-
pearance, but is smaller, has less curvature, and
low, flat-topped, closely set ribbing with striae
present only between the ribs (Fig. 16).

Caecum donmoorei, n. sp.

DescriTption: Shell tapered with slight curva-
ture; 27 annular ribs well-spaced, raised,
rounded-topped (Fig. 31); primary striae in inter-
space thick; secondary striae thin; all striae con-
tinue over surface of ribs (Fig. 32); Septum
slightly convex, bearing broad, weak mucro
angled to right; two small circular ribs around
circular aperture; no varix; color white in holo-
type, some specimens tinged brovm near aper-
ture; length 1.4 mm.

Remarks: This species has round-topped and
striated ribs as opposed to the smooth, flat -topped
ribs of C. regulare. It differs from C. giuyulio
which has rounded, robust, but not so raised, ribs

which are small, smooth, and bear no striae.
There is also no similarity to C. toniatum Verrill
and Bush which has strong ribs and a very strong
mucro and appears to be confined to Bermuda.
The most distinguishing feature of C. donmoorei
which appears to justify the naming of a new
species, is the round-topped striae-covered ribs.
This species is named after Dr. D. R. Moore, a
leader in the field of the study of the Caecidae.

Tijpe -locality: Holotype: In 5 m of water in
Sprat Bay, Water Island, USVI. Four paratypes
were found in Ruyter Bay and Elephant Bay at
similar water depths and of low wave-energy.

Ti/pen: Holotype deposited in 1977 in the Dela-
ware Museum of Natural History #119521. Para-
types were placed in the collection at the Florida
Bureau of Geology, Tallahassee, #12909.

ACKNOWLEDGMENTS

I am grateful directly to Dr. J. R. Taylor for
allowing the examination of the collection held at
the British Museum of Natural History in Lon-
don, and indirectly to Dr. D. R. Moore for his
work of classifying some of this collection. I am
also grateful to Philip Dawson of St. Thomas for
his aid in the collection of the samples, and to
Dr. S. W. Wise and Dr. R. Wright of the Depart-
ment of Geology of The Florida State University,
Tallahassee, and Dr. D. R. Moore, University of
Miami, Miami, for their reading and criticism of
the manuscript. Scanning electron micrographs
were taken on an ISI Supermini I, housed in the
Department of Geology at The Florida State
University. Support in part was provided by NSF
grant #121-323-210.

LITERATURE CITED

Moore, D. R. 1969. A new Caecum from the tropical Western
Atlantic. TheNautilm 83(l):26-28.

. 1970. A new Caecum from Puerto Rico and the Vir-
gin Islands. Bull. Mar. Sn. 20(2):368-373.

. 1972. Ecological and systematic notes on Caecidae

from St. Croix. U. S. Virgin Islands. Buil. Mar. Sci. 22(4):
881-899.

Weber, J. A. 1961. Marine shells of Water Island, Virgin Is.
The Nautilus 75(2):55-60.

106 THE NAUTILUS

April 23. 1979

Vol. 93 (2-3)

DISCOVERY OF LIVING BIVALVED GASTROPODS IN THE FLORIDA KEYS

Donald R. Moore

University of Miami Rosenstiel School of

Marine and Atmosphere Science

Miami, Florida 33149

Mabel Fentress Miller

and Environmental Education Propram,

Science Education Dept.

Dade County Public Schools

1410 Northeast Second Avenue

Miami, Florida 33132

The first living bivalved gastropod was observed
by Kawaguti just twenty years ago (Kawaguti
and Baba, 1959). A year later, in October 1900,
Kawaguti visited Miami in an effort to find these
animals in the western Atlantic. He was unsuc-
cessful, but shortly after Edmunds (1962) re-
ported a species from Jamaica. This species was
described as Berthelinia caribbea Edmunds, 1963.
B. canbbea was reported from Puerto Rico by
Warmke (1966), and later from Panama and
Brazil (Meeder and Moore, 1972).

The search for B. caribbea in United States
waters was unsuccessful for many years; then
one of us (MFM) collected eight live specimens in
the Florida Keys on 14 July 1978. They were
collected in sea wall scrapings from a canal off
Tavernier Creek, Plantation Key. After being
observed alive, they were preserved in alcohol.
Four of these were donated to the School of Marine
Science, University of Miami.

This is the first living species of the family
Juliidae to be reported from Florida. A fossil
species, Julia Jloridana Dall, 1898, was described
(as a pelecypod) from the Oligocene of north-
western Florida along the Chipola River. The
genus Julia is presently found living in the cen-

tral and western Indo-Pacific, and is known from
two fossil species in the western Atlantic area.
Berthelinia caribbea is not likely to be found as
a fossil, however, as it is extremely thin-shelled.

B. caribbea is now known from the Florida
Keys, Jamaica, Puerto Rico. Panama, and Brazil.
It appears to have plankton ic larvae, and should
be found at many more localities in the Tropical
Atlantic.

LITERATURE CITED

Dall. W. H. 1898. Contributions to the Tertiary fauna of Flor-
ida. Trans. Wagner Free Inst. Sci. Philad. 3(4):.571-947.
pis. 23-.i5.

Edmunds. M. 1962. Bivalve gastropod from .Jamaica. Nature,
195:402.

. 196.3. Berthelima raribben n. sp.. a bivalved gas-
tropod from the west Atlantic. .1. Linn. Soc. London
44(9)2): 7.31 -7.39, pi. 1.

Kawaguti. S. and K. Baba. 19.59. A preliminary note on a two-
valved sacoglossan gastropod. Tamanuvalva limar. n. gen.,
n. sp., from Tamano. .Japan. Biol. .J. Okayama Univ. 6(3-4):
177-184. 10 figs.

Meeder. .1. F. and D. R. Moore. 1972. The extension of range of
RcrthrUiua mnhhea Edmunds to Brazil and Panama (Mol-
lusca. (lastropoda). Carib. Jmir. Sci. 11(3-4):1.")9-161.

Warmke. G. 1966. Two species of the bivalved gastropod Berthe-
linia found in Puerto Rico. The Nautilus 79(4):1.39-141.

This issue of \'ol. 9:^ cnnibines numbers 2 and 3. Numbei- 1 will h' published in October. 1979.

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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,
parasitological, ecological, and experimental
projects.

Several museums of natural history have ex-
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ISSN 0028-1344

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The American Museum of Natural History
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The American Museum of Natural History
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The Ohio State University
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Los Angeles County Museum of Natural History
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Woods Hole Biological Laboratory
National Marine Fisheries Service
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Division of Marine Geology
School of Marine and Atmospheric Science
10 Rickenbacker Causeway
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Division of Mollusks
U. S. National Museum
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Department of Invertebrates
Field Museum of Natural History
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Museum of Zoology
The Ohio State University
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THE

NAUTILUS

Volume 94, number 4 — October 30, 1979

ISSN0028-1344

CONTENTS

Donald M. Allen

Bioldgical aspects of the Calico Scallop. Argopecten Gibbu.% determined by Spat Monitoring 107

Francis R. Home and Steve Mcintosh

Factors influencingdistribution of Mussels in the Blanco Riverof Central Texas 119

Miguel A. Klappenbach

Allocation of "Mnryinclln "Cordrroi Carcelles, 1953 to a New Genus in the

Volute Subfamily Odontocymbiolinae (Gastropoda) 133

Alex S. Tompa

Localized egg shell dissolution during development in Stenotrema Leai

(Pulmonata: Polygyridae) 136

Arthur H. Clarke

Gastropods as indicators of Trophic Lake Stages 138

Leslie Hubricht

A New Species of Amwico/a from an Arkansas Cave (Hydrobiidaoe) 142

K. Elaine Hoagland

The Behavior of Three Sympatric Species of Orpiduln

(Gastropoda: Pi'osobranchia) from the Atlantic, with implications for Evolutionary Ecology .... 143
John J. Jenkinson

Tlie Occurrence and Spread of Corbicula Manilensis in East -Central Alabama 149

Archie L. Jones

Descriptionsof Six New Forms of Florida Tree Snails, LM7?iusFa.sCTa<2i.s 153

R. Tucker Abbott and C. John Finlay

Oiicdrnii^ Gismnni. a New Muricid Gastropod from the West Indies 159

Susan B. Gallagher and George K. Reid

Population Dynamics and Zonation in the Periwinkle Snail, Littorina Angulfera.

of the Tampa Bay, Florida, Region 162

Arthur H. Clarke

Sphaeriidae as indicators of Trophic Lake Stages 178

A. Omura. W. K. Emerson and T. L. Ku

Uranium - Series Ages of Echinoids and C«rals from the Upper Pleistocene

Magdalena Terrace, Baja California Sur, Mexico 184

Walter E. Klippel and Paul W. Parmalee

The Naiad Fauna of Lake Springfield, Illinois: an Assessment after Two Decades 189

Publications Received ii

PUBLICATIONS RECEIVED

Leathern. Wayne and Don Maurer. 1979. (Revised edition of)
Phylum Mollusca: A Guide to the Mollusca of Delaware
Bay Region. 42 mimeographed pp. A key to the known
species. $3.00. Publications, C.M.S., Univ. Delaware. Newark,
DE 19711.

Gibson-Smith. J. and W. 1979. The Genus Arcinella (Mollusca:
Bivalvia) in Venezuela and Some Associated Faunas. Geos
no. 24: 11-32, 3 pis. A. jungi and A. candelariana n. spp..
and Nicotia n. subgenus (type: Chama draconis Dall) from
the Miocene are described. Purpura weisbordi n. sp. is what
Weisbord. 1962. called P. patula Linnaeus. Many of
Weisbird'.s 1962 species are sv-nonymized.

Menzel, R. W. 1974. Portuguese and Japanese Oysters are the
Same Species. Jour. Fish Research Bd. Canada 31(4):
45:3-456. The author suggests, on biological evidence, that
Crassostrea angidata Lamarck (1819) from Portugal be con-
sidered a subspecies of C. gigas (Thunberg. 1793) from
Japan, the latter possibly having been introduced from Por-
tugal.

Purchon, R. D. 1978. An Analytical Approach to a Classifica-
tion of the Bivalvia. Phil. Trans. Royal Soc. London. B. 284:
425-4.36.

/( Naturalkla Siciliano. vol. 1 and 2 (1977-78). A new quarter-
ly containing several scientific papers on mollusks. Instituto
di Zool. della Univ., 18 Via Archirafi, Palermo, Italy 90123.

Eyster. Linda S. 1979. Reproduction and Developmental
Variability in the Opisthobranch, Tenellia pallida. Marine
Biology, vol. 51, pp. 1,3;V140. Pelagic and non-pelagic develop-
ment occurs within single population.

Ti-yonia, no. 1. Catalog of the Chiton T>T)es of the Academy of
Natural Sciences of Philadelphia. By G. M. Davis. R.
Robertson and M. Miller. .56 pp., mimeographed. .$7.00.
Miscellaneous publication of the Dept. Malacology-, Acad.
Nat. Sci. Phila.. Phila.. PA 19103. Lists primary t.vpes and
syntypes. with complete data, and by geographical areas.

Jaume, Miguel L. and Alfredo de la Torre. 1976. Los Urocop-
tidae de Cuba (Mollu.sca - Pulmonata). Cieticias Biological
(Habana). no. .53, 122 pp. Contains numerous new genera
and specie.s. Originally published in Circulares del Museo y
Biblm. Zool. Habana, 1972. pp. 1.526-1649.

Davis, George M. 1979. The Origin and Evolution of the
Gastropod Family Pomatiopsidae, with Emphasis on the
Mekong River Triculinae. Monograph 20. Acad. Nat. Sci.
Philiulclphia. 120 pp. An extensive zoogeographic and
phylogenetic review, with two new genera. The author
employs the u.se of Triljes and erects two new names under
the subfamily Triculinae.

Gate, Crawford N. 1979. A Review of the Tiiviidae. Memoir
10, San Diego Society of Naiural Histoi-y. 126 pp., 177 figs.
An extensive review, with five new genera and 40 new
species.

Zhuang. Qi-qian. 1978. Studies on the Mesodesmatidae
(Lamellibranchia) off the Chinese Coast. Studia Marina
Sinira. vol. 14. no. 14, pp. 69-74, 1 pi. Treats with Atactodea,
Darila Oiccclla and Anapelta retrocunvexa n. sp. from
N;ur/,how Island, China.

Pidmonates. Vol. 2 A, Systematics. Evolution and Ecology
(edited by V. Fretter and J. Peake). .540 pp. Academic Press,
London, N. Y. 1979. $50.75. 10 chapters of varying contents
and quality, some outstanding on systematics. distribution,
classification, natural selection and ecology by fourteen
well-known malacologists.

Pulmonates. Vol. 2 B, Economic Malacolugy u-ith particular
reference to Achaiina fulica. by A. R. Mead. 1.50 pp.
Academic Press, London, N. Y. 1979. $2,520. This is an up-
date and condensed version of Dr. Mead's 1961 "The Giant
African Snail" ($8.00). A previous book. Medical and
Economic Malacology, by Malek and Cheng, published by
Academic Press in 1974, covers the economic field more
broadly and adequately.

FORTHCOMING BOOK
SEA SHELLS OF WESTERN EUROPE

by Philippe Bouchet
Photography by F. Danrigal and C. Huyghens

An exquisite little guide to the habits,
life histoiT and identification of the com-
mon moUuskes of Western Europe. 142
spectacular, colored photographs of egg-
laying, breeding, and reproducing, as well
as very colorful, close-up views of snails,
nudibranchs, clams and squids. Also con-
tains 11 plates of identification figures. One
of the loveliest of the new generation of
shell books. Hardback. 144 pp. $8.95.
Published by

American Malacologists, Inc.

P.O. Box 2255
Melbourne, FL .32901 USA

Vol.94 (1)

October 30, 1979

THE NAUTILUS 107

BIOLOGICAL ASPECTS OF

THE CALICO SCALLOP, ARGOPECTEN GIBBUS,

DETERMINED BY SPAT MONITORING'

Donald M. Allen

NOAA, National Marine Fisheries Service

S(iutheast Fisheries Center

Miami, Florida 33149

ABSTRACT

Biological information on the calico scallop. Argopecten gibbus, was collected
using spat traps as monitoring devices on the Cape Canaveral grounds off the
Florida east coast from March 1970 to October 1971. The shells of noung scallops
(spat) differ in shape and color from those of adult scallops. Spat and, by deduc-
tion, the larval scallop.% occurred at five sampling locations off Cape Canaveral in
depths of 9 to 2Jf m; spat were most abundant at the 18 m site. There was no
evidence that scallop larvae survived in estuarine waters in the Cape Canaveral
area. Based on spat distribution, la}-vae were apparently distributed throughout
the water column but were least abundant near the surface. Seasonally, spat were
most abundant in the spring. Growth estimates .show that young scallops can reach
1.5 m,m shell height in 1 month from spawning, 17.0 mm in 2 months, and 28.0 mm
in 3 months. Setting apparently occun-ed at a minimum size of 0.25 mm shell
height and apnt showed strong byssal attachment up to at least 5.0 or 6.0 mm shell
height. Spat may utilize filamentous host organisms, such as hydroids. for setting,
perhaps before attaehment to shell. Numerous inveHebrates were associated with
calico .scallops in the traps, but calico scallops ivere generally dominant.

Based on spat abundance, spawning of adults occurred during all seasons, but
intensity was highest in spring (March through May) when bottom water
temperatures associated unth spauming scallops were probably about 18°C.

Recommendations for future spat monitoring are discussed.

The calico scallop, Argopecten gibbus, supports
a small fishery off the southeastern United
States. The scallop grounds are located off North
Carolina, off the Florida east coast, and in the
northeastern Gulf of Mexico (Figure 1). Abun-
dance and distribution of scallops on the grounds
are seasonally and annually variable, which has,
in part, contributed to the slow development of
the fishery. To recognize factors controlling the
abundance and distribution of the calico scallop,
the Bureau of Commercial Fisheries (now the Na-
tional Marine Fisheries Service), Miami, Florida,
conducted laboratory and field studies of the
biology of this species from 1969 to 1971.

Biological information concerning certain

' Contribution Number 79-37M, NOAA, National Marine
Fisheries Service, Southeast Fisheries Center. Miami, FL
33149.

marine invertebrates has been revealed by their
habit of attaching to or "fouling" of submerged
objects (Woods Hole Oceanographic Institution,
1952; Merrill, 1965). Artificial substrates, such as
test surfaces or fouling panels, are used in
biological monitoring because of the relative ease
with which the unit of sampling effort can be
standardized and controlled (Calder and
Brehmer, 1967; Cory, 1967; Pequegnat and Pe-
quegnat, 1968). Spat collecting devices, made of
oyster shells or asbestos plates, are particularly
useful in oyster biological studies that have
direct application to the commercial fishery
(Loosanoff, 1966; Shaw, 1967).

Scallops (family Pectinidae) attach to
substrates by means of byssal threads. The first
byssal attachment of young scallops after a
planktonic existence is called "setting," and the

108 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

FIG. 1. G( ncnil dixlribtituin af the calicu scattop and primary
scallop fishing grtmnds. (Modified fi^om Cummins, 1971: A Hen
and Oistello. 1972).

recently set scallops are called "spat." Setting
was described for the bay scallop, Pecten irra-
diaiK (now Atyopecteti irmdians), by Belding
(1910). Young scallops of various species will set
on natural and artificial substrates (Belding,
1910; Woods Hole Oceanographic Institution,
1952; Merrill, 1965; Brown et al., 1967; Dow,
1969; Costlow, 1969; DePalma, 1969; Turner,
Egbert, and Given, 1969 and Golikov and Scarlato,
1970.) Under natural conditions, calico scallop
spat are generally found attached to mollusk
shells, primarily the empty valves of calico
scallops (Allen and Costello, 1972). Calico scallop
spat have also attached to navigation buoys
(Waller, 1969) and plastic peanut floats (Pe-
quegnat, Gaille, and Pequegnat, 1967).

The setting habits of scallops suggested that
calico scallop spat might be effectively sampled
using artificial substrates as collecting devices.
An effective spat collector, briefly described by
Allen and Costello (1972), was developed by me in
early 1970. Later spat monitoring, using this
device, provided basic data concerning spat:
description, distribution and abundance, age and
growth, behavior, and associated organisms; and
spawning of adults. In recent years, a similar
spat collecting device has been used in a Japanese
commercial scallop culture system (Dix, 1977).
METHODS

In preliminary field tests off Cape Canaveral,
Florida (Figure 2), young calico scallops byssally
attached to a variety to cultch materials in addi-

tion to calico scallop shells. Unlaid polyethylene
line, which forms a filamentous tangle, was par-
ticularly effective as cultch. Comparison of cultch
effectiveness was difficult because many of the
larger spat dropped from the cultch as it was
removed from the ocean. To minimize the loss of
spat that may release attachment before or dur-
ing the time spat collectors were retrieved, the
cultch was contained within wire plastic or
nylon mesh of appropriate size.

The standardized spat collector (designated
"spat trap") used during most of this study con-
sisted of a small, nylon mesh bag stuffed with a
fixed quantity of unlaid polyethylene line (Figure
3). The nylon bag was 56.0 cm long and 30.5 cm
wide, with mesh openings about 3.0 mm in
diameter. Polyethylene line, diameter 9.4 mm and
length 61.2 cm, was separated into individual
filaments and placed in the bag, along with a
plastic identification label. The bag was closed by
means of a figure-eight knot tied in the bag at its
midpoint. Excess bag material was drawTi down
over the knot and tied with nylon parachute
cord, which also secured the spat trap to a ver-
tical line at a selected position in the water col-
umn. These spat traps survived well in the
marine environment, because their components
did not decompose rapidly.

The spat traps filtered large quantities of
water from currents which presumably carried
the scallop larvae to the traps where the larvae
set and grew. Young scallops inside the traps
were permanently trapped when their size ex-
ceeded the 3.0 mm mesh openings. Probably few
spat less than 3.0 mm shell height^ were lost
during recovery of the traps because spat in this
size category show strong byssal attachment.

Preliminary comparative studies indicate that
standard spat traps containing 61.2 cm of unlaid
line caught more spat than mesh bags containing
no line but stretched with wire to a size and
shape similar to that of the standard traps. When
the amount of line in the traps was increased to
183.6 cm, the numbers of spat caught increased,
but their growth declined markedly. Further-
more, the tightly packed line apparently caused a
high incidence of deformed valves and mortality
among the larger spat. As noted by Merrill and

' Shell heipht is a straight measurement of the greatest
distance between the umbo and the ventral margin.

Vol. 91 (4)

October 30, 1979

THE NAUTILUS 109

■■■ \

F

yV luo't I •"<>' 2

vXv '^

)

\ 1 1 Jy^*''^ CANAVERAL

i 1 ) \.^t, ifOilCiMVtlU

A MONITORING SITES

- <y.''

81

-r

— r-

79"

78'

-r

FIG. 2. Calif (J ^calhip tspat mimitnring siten nff Cape
Caiuiveral and geographic locations along the eiixt count of
Florida,

Edwards (1975) for young sea scallops,
Placopecten magellanicus. growing in fouling
communities, "The mantle is apparently easily
injured, and evidence of serious shell malforma-
tion was seen in situations where other
organisms were in close approximation to the
scallop." In the standard spat traps, no defor-
mities occurred. Extensive mortality did occur in
standard traps that were exposed for almost 4
months, but the causes are unknovm. These traps
contained potential predators (including starfish,
crabs, and gastropod mollusks) and competitors
(bivalve mollusks) that had apparently passed
through the meshes as larvae and were
themselves trapped. In addition, the meshes were
clogged with silt.

Five sites to monitor calico scallop spat
distribution and abundance were established off
the Florida east coast near Cape Canaveral, in
depths of 9 to 24 m (Table 1, Figure 2). U.S. Coast
Guard navigation buoys or special service buoys
marked each site and enabled location and
recovery of the spat traps after exposure for ex-
tended periods of time. It was necessary to
establish the sites inshore of the greatest adult
scallop concentrations because of the absence of
large, permanent buoys in the offshore waters.

Adult scallops occurred near Buoys 1 and 2 but
were rare or absent at the remaining three sites.

In use, the spat traps were attached to a spat
monitoring array that was typically composed of
an anchor, vertical line, stabilizing float and sur-
face buoy. To facilitate recovery, the arrays were
positioned within sight of the permanent buoy at
each site. In some areas, where danger of propeller
cutoff and theft was great, the surface buoy was
retained underwater until released by a timed
magnesium fuse shortly before scheduled recovery.
For most of the comparative studies, two spat traps
were located on the vertical line at positions 0.6 m
and 6.0 m above the ocean bottom. For special pur-
poses, additional traps were located 0.9 m below the
water surface and elsewhere in the water column.

The preliminary, experimental spat collecting
devices were first set out in March 1970. After
refining techniques, standardized spat traps,
useful for comparing abundance, were exposed for
varying periods of time from July 1970 to Oc-
tober 1971. Scallops caught by both the
preliminary and standardized traps were used in
the growth study. The shortest exposure time was
11 days, and the longest, 117 days. Losses of ar-
rays were common and were attributed to strong
currents, entanglement with fishing gear, theft,
and propeller cut-off. Most of the successful
recoveries of arrays were at Buoys 1 and 2, the
sites most remote from vessel traffic or fishing
activities.

When the spat traps were recovered from the
ocean, they were placed in fine-mesh nylon bags
(mesh size about 0.75 mm) and preserved in 10%
Formalin.' Although the spat apparently released
byssal attachment upon contact with Formalin,
the fine-mesh preserving bags retained spat as
small as 0.75 mm shell height and helped main-
tain the integrity of each spat trap during the
later flushing, freezing (for preservation), and
thawing process.

The calico scallop spat (including empty shells)
and associated organisms from each spat trap
were sorted and counted. An unknowm number of
very small spat (less than 0.75 mm shell height)
may have been washed through the fine-mesh
preserving bag or overlooked by the sorters.
Other species of scallops were caught in the traps

' Reference to trade names does not imply endorsement by
the National Marine Fisheries Service, NOAA.

110 THE NAUTILUS

October 30. 1979

Vol. 94 (4)

but constituted less than 1% of those larpe
enough to be identified to species. The scallop
spat were measured for shell height. Spat less
than 1.0 mm shell height were measured to the
nearest 0.25 mm, those from 1.0 to 5.0 mm to the
nearest 0.5 mm, and those more than 5.0 mm to
the nearest 1.0 mm. Scallops from 0.25 to 27.0
mm shell height were found in the trap samples.
One trap, exposed for 35 days, contained 4,761
spat that ranged from 0.75 to 8.0 mm shell height.

Since the "catching effort" of the spat traps
varied with exposure time, catch data were stan-
dardized by calculating the average number of
spat caught per trap per day of exposure.

Thermographs recorded bottom temperatures
at Buoys 1 and 2 during most of the study period,
but there were intervals when no data were col-
lected because of thermograph malfunction or
loss.

Spat

Description

The calico scallop shell was described by
Waller (1969). Shells of calico scallop spat col-
lected in spat traps on the Cape Canaveral
grounds (Figure 4) differed in shape and color
from shells of adult scallops collected in the same
area.

Shell height was usually greater than shell
length" in .spat 1.0 to 8.0 mm height. At about
9.0 mm shell height, shell length began to in-
crease more rapidly than shell height, and from
my additional observations of larger scallops, and
those of Wells, Wells, and Gray (1964), this rela-
tionship apparently continued throughout life. In

Table 1. Locations aod depths of calico scallop spat monitoring sites
off Cape Canaveral, Florida.

Latitude

and

Distance

Buoy

longitude

trom land

Depth

don)

(m)

Buoy 1

m"

48.5^

N

9

18

»u°

38. b

W

Buoy 2

28°

49. l]

H

22

22

80°

29.0

U

Heczel Shoal

28°

38.2!

N

22

24

Buoy

8U°

21.0

U

Port C«Dsveral

28°

22.9!

N

U

17

R2 Buoy

80°

25.5

U

Port Caooveral

28°

23.8;

N

6

9

RUlt6 Buoy

80°

32.2

V

FIG. 3. Spat trap, cmutisting nf nylon mesh bag (top) and
unlaid palyethylene line (bottom right). Calico acallap spat
(center) exceed mesh openings in size. (Prom Allen and
Costello. 19721.

trawl-caught scallops, shell length did not begin
to increase more rapidly than shell height until a
shell height of about 30.0 mm was reached.

Length of the hinge line was about equal to
shell length in spat 1.0 to 1.5 mm shell height.
However, as shell height increased, hinge line
length increased more slowly, so that at 8.0 mm
shell height (approximately 8.0 mm shell length)
hinge line length was 6.0 mm.

Spat less than about 10.0 mm shell height were
noticeably compressed, or flattened, as compared
with the strongly inflated adult scallops. For spat
ranging from 3.5 to 8.0 mm shell height, depth'^
was only about 27 to 31% of shell height. As shell
height increased, depth increased disproportion-
ately. For spat 19.0 to 23.0 mm .shell height,
depth was about 37 to 46% of shell height, and
for scallops 37.0 to 65.0 mm shell height (caught
by bottom trawl), depth was about 54 to 64% of
shell height.

There was a difference in convexity* between
the left (upper) and right (lower) valves in spat
from 1.5 mm up to at least 8.0 mm shell height.
For spat 3.5 to 4.5 mm shell height, the left valve.

' Shell length i.s a straight line mea.-iurement of the greatest
distance between the anterior and posterior margins.

' Depth is the sum of the convexities (see footnote (i) of the

left and right valves.

' Conve.xity is the maximum distance lietween the exterior
surface of a v.dve and the measuring platfunn. me;usured
along a line perpendicular to the measuring platform (Waller,

V(,1.91 (1)

October 30, 1979

THE NAUTILUS 111

FIG. 4. Calico scallop spat from 2.5 to 16.0 mm shell
valve in on bottom.

strongly convex, accounted for 65 to 81% of the
depth, while the right valve, weakly convex, ac-
counted for only 18 to 34% of the depth. Convexi-
ty of the valves became more equal as shell
height increased. Waller (1969), apparently
discussing adult scallops, observed that the valves
were "generally equiconvex to slightly left con-
vex."

Spat ranging from 0.75 to 18.0 mm shell height
had white, tan, violet, brovm, red-brown, and
orange-brown valves. Some mottling or banding
occurred on spat as small as 2.0 mm shell height.
Colors on the left valve were darker than those
on the right valve, which was generally white or
light tan. Colors on the left valve became darker
and more intense as size increased. White and
tan were common base colors on the left valve of
spat 0.75 to 8.0 mm shell height, grading into
brown and red-brown as size increased up to 18.0
mm shell height.

A fairly common characteristic of spat, par-
ticularly those from about 4.0 to 8.0 mm shell
height, was a white streak bisecting the left

height. For e<wh pair, kjt rale

lilt top and right

valve, extending from near the umbo to the ven-
tral margin and encompassing the width of a few
ribs.

LHstribution and Abundance

The general distribution of the calico scallop
was summarized from several sources by Allen
and Costello (1972), who stated that the range of
this species ". . . extends from the northern side
of the Greater Antilles and throughout the Gulf
of Mexico to Bennuda and slightly north of Cape
Hatteras." According to Allen and Costello (1972),
"The greatest known abundance is located off the
Florida east coast near Cape Kennedy [Cape
Canaveral], with lesser concentrations near Cape
Lookout, N. C, and in the northeastern Gulf of
Mexico near Cape San Bias, Fla." Sporadic com-
mercial concentrations also have been reported
off Savannah, Georgia, and along the west coast
of Florida, from off Egmont Key to Key West
(Figure 1).

Although the calico scallop may consist of one
population throughout its range, with planktonic
larvae from stock in one area contributing to

112 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

stock in another area, there is little evidence to
suprK)rt this theory. Oceanic currents probably
determine the direction of transport of the lan'ae
(Waller, 1969). Therefore, the Gulf Stream
system, and associated countercurrents, may be
important in larval distribution. Kirby-Smith
(1970) suggested that part of the North Carolina
calico scallop stock may result from larvae
transported northward from the Cape Canaveral
grounds by the Gulf Stream. The origin of the
calico scallops on the Cape Canaveral grounds is
unknown. These scallops may be either self-
sustaining or partially dependent upon larvae
transported from more distant spawning stocks,
presumably (but not necessarily) located farther
south than the lower end of the Cape Canaveral
grounds near Stuart, Florida. Calico scallops oc-
cur in the Florida Keys (Waller, 1969), and these
scallops may supply larvae to the Cape Canaveral
grounds (Figure 2). This hypothesis, however,
does not negate the fact that there is a large
stock of spawning scallops on the Cape Canaveral
grounds, and water circulation in the Cape
Canaveral area might be expected to retain

scallop larvae on the grounds until setting occurs,
since surface currents off Cape Canaveral reverse
direction to north or south with wind changes,
and bottom currents converge toward the cape
from offshore (Bumpus, 1973).

Calico scallop spat were caught in traps at all
five study sites off Cape Canaveral (Table 2). This
might be e.xpected since the wide distribution of
adult scallops on the Cape Canaveral grounds
(Drummond, 1969) would presumably contribute
to the wade distribution of larvae in this area.
The intensity of spat setting (or survival) be-
tween sites was variable. Where mmparisons be-
tween sites could be made, they showed spat to
be most abundant, generally, at Buoy 1 and least
abundant at Port Canaveral RWR6 Buoy. For ex-
ample, traps exposed from May 25 to June 26,
1971 (35 days) caught 2,320 spat at Buoy 1 (9 km
offshore, 18 m of water), 895 spat at Buoy 2 (22
km offshore, 22 m), and 21 spat at Port Canaveral
RWR6 Buoy (6 km offehore, 9 m) (Table 2).
Variability in setting between locations was also
observed in the northeastern Gulf of Mexico,
where calico scallop spat attached to biofouling

Table 2. Seasonal abundance of calico scallop spat at monitoring sites oft Cape Canaveral, Florida, July 1970 to October 1971.

Spat Trap hxposure

Buoy 1

Buoy 1

Hetzel

Total

Shoal Buoy
Per day

Port Canaveral
R2 Buoy

Port Canaveral
RWR6 Buoy

Period Daya

Total Per day

Total Per day

Total Per day

Total Per day

7/21/70
8/26/70
11/11/70
1/06/71
1/06/71
1/24/71
1/24/71
2/16/71
3/16/71
3/16/71
4/01/71
4/20/71
5/25/71
6/26/71
8/24/71

8/26/7U
11/11/70
1/24/71
1/24/71
2/16/71
2/16/71
3/16/71
3/16/71
4/01/71
4/20/71
4/12/71
5/25/71
6/26/71
8/24/71
10/27/71

35
76
74
18
41
23
51
27
16
35
11
35
32
59
64

227 6.5

39 0.5

134 1.8 139 1.9

4,562 130.3 1,531 43.7

2,300 65.7 1,181 33.7

2,320 72.5 895 28.9

142 2.4 536 9.1

21 0.3 70 1.1

-number of spat per trap

60

3.3

384

9.4

361

15.7

35

1.3

1

0. 1

1 Spat size ranged from 0.23 to 27.0 mm shell height.

2 Spat traps were positioned about 0.6 m above ocean floor.

3 Dashes Indicate no data (i.e., trap was not exposed, or if exposed, not recovered).

Vol.94 (4)

October 30, 1979

THE NAUTILUS 113

Table 3. Vertical distribution of calico scallop spat at monitoring sites off Cape Canaveral,
Florida, November 19/U to October 1971.

Buoy 1

Buoy 2

Spat trap e

xposure

period

Surface

Intermediate

Bottom

Surface

Intermediate

Bottom

11/11/7U -

1/24/71

__1

1.2

-numb

er of spat
1.8

per trap

per day

2.2

1.9

1/24/71 -

3/16/71

—

1.0

13.6

~

0.7

3.7

3/16/71 -

4/20/71

—

110.5

130.3

~

44.4

43.7

4/20/71 -

5/25/71

0.5

136.0

65.7

0.3

75.9

33.7

5/25/71 -

6/26/71

—

41.7

72.5

~

26.5

28.9

6/26/71 -

8/24/71

—

2.2

2.4

~

15.2

9.1

8/24/71 -

10/27/71

~

1.3

0.3

~

1.2

1. 1

1 Dashes indicate no data.

Note: Surface traps were positioned about 0.9 m
above ocean floor, and bottom traps 0.6 m

arrays more abundantly at sites 19 km offshore
than at sites 4 or 41 km offehore (Pequegnat and
Pequegnat, 1968).

The usual distribution of adult calico scallops
indicates that the larvae are restricted to open
marine water. The larvae, however, sometimes
enter estuarine waters, based on reported oc-
currences in semi-enclosed sounds of juveniles in
North Carolina (Waller, 1969) and adults in Ber-
muda (Aurelia, 1970). There was no evidence that
the larvae survived and set in estuarine waters in
the Cape Canaveral area. Relatively few spat
were caught at Port Canaveral RWR6 Buoy, the
site closest to shore and to an estuarine inlet
(Figure 2, Table 1). Furthermore, a year-long
biofouling study at nearby Ponce de Leon Inlet
produced three species of mollusks, but no
scallops (Richards and Clapp, 1944).

Larval calico scallops are apparently
distributed throughout the water column, since
spat were found in traps positioned at the ocean
surface, at intermediate depths, and near the bot-
tom (Table 3). Similar vertical distribution of lar-
vae was indicated by Pequegnat and Pequegnat
(1968) who reported calico scallop spat from
biofouling arrays distributed from surface to bcjt-
tom in 46 m of water in the northeastern Gulf of

below ocean surface, intermediate traps 6.0 m
above ocean floor.

Mexico. Off Cape Canaveral at Buoys 1 and 2,
from April 20 to May 25, 1971, there were very
few spat in the surface traps as compared with
those in the intermediate and bottom traps. At
each of these two sites, comparisons of in-
termediate and bottom catch rates between
November 1970 and October 1971, showed that
vertical distribution of spat was highly variable
during certain exposure periods, indicating varia-
tions in larval abundance or spat survival be-
tween the intermediate depths and the bottom at
these seasons (Table 3).

Calico scallop spat were caught year-round in
traps off Cape Canaveral; at least a few spat
were caught during every exposure period (Table
2). This suggests continuous recruitment of young
scallops to the population on the grounds,
although there may not be a simple relationship
between setting success in the traps and success
on natural substrate in the immediate area. For
example, while the numbers of spat at Buoy 1
generally exceeded those at Buoy 2 (Table 2),
trawl catches of adult scallops on the ocean floor
at Buoy 2 greatly exceeded those at Buoy 1. The
substrate at Buoy 1 consisted of sand and flat
conglomerate rocks, while that at Buoy 2 was
sand and live shell rubble.

Ill thp: nautilus

October 3U. 1979

Vol.94 (4)

There were distinct seasonal variations in spat
abundance. At Buoy 1, between July 21, 1970 and
October 27, 1971, catches ranged from 0.3 to 130.0
spat per trap per day. Based on catches at Buo.v
1, where the data are most complete, and sup-
plemented by data from Port Canaveral R2 Buoy,
the great majority of spat were caught in traps
exposed between January 6 and June 26, 1971,
with peak numbers from March 16 to April 20,
1971. Relatively few spat were caught during the
remainder of the year. A similar pattern of spat
abundance occurred at Bu(jy 2(Table 2).

Age and Growth

Age and growth of young calico scallops were
estimated from the maximum sizes of spat caught
in the spat traps at the end of each exposure
period. For example, spat traps exposed for 35
days contained spat ranging from 0.25 to 10.0 mm
shell height; the size composition from one trap
is shown in Figure 5. Assuming no movement of
spat into the traps after initial setting, the set-
ting time of these scallops had to be within the
35-day exposure period. Under laboratory condi-
tions, calico scallop larvae set 16 days after
spawning, at about 0.25 mm shell height (Costello
et al., 1973). Therefore, age of the 10.0 mm spat in
the traps could not exceed 51 days (16 days from
spawning to set, plus a maximum of 35 days in
the traps.) In estimating growth, it was assumed
that the largest spat in the traps (10.0 mm .shell
height) set on the first day of trap e.xposure.
Evidence that spat set soon after the traps were
exposed was based on the size ranges of spat in

1 234567B9I0
SHELL HEIGHT IN MILLIMETERS

FIG, .5. Size composition of calico scallop spat from spat trap
exposed at Biuiij 1 off Cape Canaveral Florida, April 20 to
Mail £>. 1971.

ACE rN DAYS

FIG. (). KsliiHuted aye and yrimih of eidico scallop spat from
spat traps exposed off Cape Canaveral. Florida March 1970 to
Cktober 1971. Age U number of days from spawning to set
I Hi) plus number of days of spitt trap exposure.

traps exposed for short periods of time. In one
trap exposed for 11 days, many spat from 0.25 to
1.0 mm shell height were found. Since spat set at
0.25 mm shell height, it is reasonable to expect
that the 1.0 mm .spat set first, on or soon after
the first day of trap exposure. While this
assumption regarding time of spat setting may
not be entirely correct for all situations, it is
probably the best assumption that can be made
based on the available data. If it is assumed that
the largest spat set after the first day of trap ex-
posure, then estimated growth would be more
rapid than reported here.

Tliis method of estimating age as related to
size was applied to the largest spat from each ex-
posure period and the results are shown in
Figure 6. Based on these data, calico scallops are
capable of reaching approximate sizes of 1.5 mm
shell height in 1 month from spawTiing, 17.0 mm
in 2 months, and 28.0 mm in 3 months. This
growth rate is compatible with results of
preliminary studies of marked calico scallops on
the Cape Canaveral grounds, reported by Miller
and Hudson', which indicate that scallops reach
40 to 45 mm shell height in 6 to 8 months.

' Miller, G. C. and J. H. Hudson. Age and growth of the calico
scallop, Argopecten gibbits. Manuscript in preparation. Na-
tional Marine Fisheries Service. Southeast Fisheries Center.
Miami Laboratory. Miami. FL :fil49.

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 115

Preliininaiy studies indicate that growth rate
of spat in the traps is affected by location in the
water column and, probably, by the density of
spat. At Buoy 2, spat in a trap 0.6 m above the
ocean bottom grew more rapidly than those in
traps 6.0 m off the bottom and 0.9 m below the
water surface. Similarly, Merrill and Posgay
(1968) observed that juvenile sea scallops grew
faster on the ocean bottom than on navigation
buoys. Also at Buoy 2, in three traps located 0.6
m off the bottom and exposed for 72 days, the
maximum size of spat in each trap decreased
with increased number of spat per trap.

Behavior

Information concerning setting and byssal at-
tachment of calico scallops in respect to size has
been reported briefly. The larvae set at about 0.25
mm shell height in the laboratory (Gistello ct al.,
1973). Calico scallop spat have been reported by
size and attachment as follows: 1 to 8 mm
(presumably shell height) from plastic floats (Pe-
quegnat, Gaille, and Pequegnat, 1967); 2.0 to 7.5
mm shell length, among epifauna on shells of liv-
ing calico scallops (Wells, Wells, and Gray, 1964);
and 3 to 5 mm shell length, attached to the shells
of dead calico scallops, primarily (Commercial
Fisheries Review, 1962).

The sea scallop showed a progressive loss of
byssal attachment as size increased (Caddy, 1972).
The calico scallop apparently behaves similarly,
from observations on recovered spat traps. Off
Cape Canaveral, setting apparently occurred at a
minimum size of 0.25 mm shell height, since this
was the minimum size of spat in the trap
samples. Strong byssal attachment to the ex-
teriors of the traps was shown by spat up to at
least 5.0 or 6.0 mm shell height. Very few spat
larger than 10.0 mm in height were found at-
tached to the exteriors of the traps at recovery,
although many spat larger than 10.0 mm were
contained inside the traps where escape was im-
possible. This size difference suggests weakened
byssal attachment by the larger spat, since most
had apparently detached from the e.xteriors of the
traps upon reaching 10.0 mm shell height or were
dislodged during trap recovery. Calico scallops as
large as 38 mm shell height occasionally wei-e
found attached to dead scallop shells in trawl
catches on the Cape Canaveral grounds. From

observations on calico scallops resting on the bot-
tom, in Bermuda, Waller (1973) reported "The
majority of the largest individuals [50 to 60 mm
shell height] lie free, without byssal attachment,
although many mature individuals attach a weak
byssus to dead shell and coral fragments."

A>i!^uciated Orgarmms

Setting, growth, and survival of scallops are
positively influenced by certain sessile plants and
animal which form a hospitable habitat. Young
bay scallops attached to seagrass (Belding, 1910),
algae (Marshall, 1960), and hydroids (Zahl, 1969).
Young kelp scallops, Leptopecten latiauratus
were found in the interstices of erect bryozoans
(Brown et al., 1967) and attached to colonial in-
vertebrates (particularly hydroids) and algae
(Turner, Ebert, and Given, 1969). According to
Dow (1969), young sea scallops first set on bryo-
zoans that are attached to adult scallop shells
and at a larger size, attached themselves directly
to shells or bottom debris. Merrill and Edwards
(1975) noted, however, that sea scallop spat will
set "on sedentary branching plants and animals,
or- any other hard surface on or above the ocean
floor which offers freedom of shell movement on
all sides."

Before the inception of the calico scallop spat
monitoring study, most calico scallop spat had
been caught by trawl or dredge. Under these cir-
cumstances, spat as small as 3.0 mm shell length
were found attached to the dead shells of calico
scallops (Commercial Fisheries Review, 1962).
Primary setting of very small calico scallop spat
on filamentous plants or animals before attach-
ment to mollusk shells was not reported.
However, spat 2.0 to 7.5 mm shell length were
among the epifauna attached to the shells of liv-
ing calico scallops (Wells, Wells, and Gray, 1964).
In addition, calico scallops 1 to 8 mm
(presumably in shell height) were reported from
plastic floats (Pequegnat, Gaille, and Pequegnat,
1967). Attachment, in the last two cases, was not
necessarily directly to the shells or floats, but
perhaps to the "pioneer" fouling organisms
already affixed. Data presented by Pequegnat,
Gaille, and Pequegnat (1967) indicated that calico
scallop spat occurred in greater numbers on
plastic floats exposed 8 and 12 weeks than on
floats exposed 2 and 4 weeks, and that the floats

116 THE NAUTILUS

October 30, 1979

Vol. 94 (1)

Table 4.

Estimated spawning periods of calico scallops oft Cape Canaveral,
July 1970 to September 1971.

Florida,

Spat trap exposure
periodl-

Catch of
spat

Mlmlmura
spat size

Estimated
age of spat

Estimated spawning
period

(per day)

(mm)

(days)

7/21/70 -

8/26/70

6.5

3.U

39

7/05/70

- 7/18/70

8/26/70 -

11/11/70

0.5

4.0

44

8/10/70

-

9/28/70

U/U/70 -

1/24/71

1.8

1.0

27

10/26/70

-

12/28/70

1/06/71 -

2/16/71

9.4

0.75

23

12/21/70

-

1/24/71

1/24/71 -

2/16/71

15.7

O.S

20

1/05/71

-

1/27/71

1/24/71 -

3/16/71

13.6

1.5

32

1/08/71

-

2/12/71

3/16/71 -

4/20/71

130.3

1.0

27

2/28/71

-

3/24/71

4/20/71 -

5/25/71

65.7

1.0

27

4/04/71

-

4/28/71

5/2 5/71 -

6/26/71

72.5

1.0

27

5/09/71

-

5/30/71

6/26/71 -

8/24/71

2.4

0.75

23

6/10/71

-

8/01/71

8/24/71 -

10/27/71

0.3

4.0

44

8/08/71

-

9/13/71

1 Traps «ere located at Buoy 1 except fo
1/24/71 to 2/16/71, which were at Port
about 0.6 m above the ocean floor.

acquired growths of hydroids before calico
scallops became present.

During the present study, filamentous marine
plants and animals were found attached to array
lines and spat traps. On more than one occasion,
small calico scallop spat 0.75 to 4.5 mm shell
height (mostly 1.5 to 2.0 mm) were found among
attached hydroids (unidentified). Attempts at sea
to determine if spat were byssally attached to the
hydroids, rather than directly to array lines or
spat traps, were unsuccessful because of rough
sea ronditions, and live spat had detached before
microscopic examination could be made. These
observations suggest, however, that very small
calico scallop spat may utilize filamentous host
organisms for setting, perhaps before later at-
tachment directly to shell. A cycle of dependence
may be operating, since certain species of
hydroids and erect bryozoans, which may host
calico scallop spat, were reported by Wells, Wells,
and Gray (1964) as common among epifauna at-
tached to the shells of living calico scallops.

Most organisms in the spat traps apparently

r those exposed from 1/06/71 to 2/16/71 and
Canaveral R2 Buoy. All traps were positioned

arrived as planktonic larvae and included
numerous invertebrates (coelenterates, annelids,
mollusks, echinoderms, crustaceans, and
tunicates) and, rarely, fishes. Calico scallops were
generally the dominant macroscopic animals in
respect to biomass and, with the possible excep-
tion of amphipods, in numbers. Barnacles were
common in the traps and were sometimes
attached to calico scallop spat. At least some bar-
nacles attach when calico scallops are young: a
barnacle 2.0 mm diameter at its base was found
attached to a spat 5.0 mm shell height.

Ecological .succession in the spat traps may
have been modified or hastened by the effect of
the filamentous strands of polyethylene. Contents
of one spat trap exposed for only 11 days in-
dicated veiT rapid development of the biofouling
community or assemblage. Included were 121
calico scallop spat 0.25 to 1.0 mm shell height, 125
gastropod mollusks, and 250 amphii>)ds. Tliere
were less than 10 each of bivalve mollusks (other
than calico scallops), isopods, copepods. mysids,
crabs, and polychaetes.

Vol.M (4)

October 30, 1979

THE NAUTILUS 117

ADULTS

Spawning

The abundance and size of calico scallop spat
caught during successive trap exposure periods
were used to estimate the season and intensity of
adult spawning. The size of the smallest spat
caught during each exposure period (Table 4) was
related to age (Figure 6). For spat caught during
each exposure period, spawning was estimated to
have extended from 16 days before the trap was
first exposed to the date the trap was recovered,
less the age in days of the smallest spat caught.
It was assumed that spat abundance primarily
reflected seasonal spawning intensity, rather
than variations in survival of larvae and spat.
Estimated spawning periods from July 1970 to
October 1971 are shown in Table 4. Spawning ap-
parently occurred during all seasons, but intensi-
ty was greatest in the spring. Following low
spawning intensity in July, and lower intensity
from August into December, spawning increased
in late December or January and peaked in
March. High spawning intensity continued
through April and May, followed by an abrupt
decrease in June and low spawning intensity into
September.

There is no direct evidence that spat setting on
the Cape Canaveral grounds are entirely or par-
tially the first generation progeny of scallops
spawning in that area. However, the spawning
pattern determined from seasonal distribution
and abundance of spat in this study is similar to
the spawning pattern determined from ovarian
color changes of calico scallops on the Cape
Canaveral grounds (Roe, Cummins, and Bullis,
1971; Miller, Allen, Costello, and Hudson'). Fur-
thermore, as explained previously, water circula-
tion in the Cape Canaveral area might be ex-
pected to retain scallop larvae on the grounds un-
til setting occurs.

Spawning of calico scallops, similar to spawn-
ing of other bivalves, is influenced by water

' Miller. G. C. D. M. Allen. T. J. Costello. and .J. H. Hudson.
Maturation of the calico scallop. Argapecten gibbus. deter-
mined by ovarian color changes. Manuscript in preparation.
National Marine Fisheries Service, Southeast Fisheries
Center, Miami Laboratory, Miami, FL 33149.

temperature changes. In the laboratory, spawning
of ripe calico scallops was induced by raising
water temperatures from about 20° to 2.5°C
(Cxi.stello et ai, 1973), but these temperatures are
not necessarily critical for spawning. In the
natural environment off Cape Canaveral, daily
mean temperatures of bottom water at Buoys 1
and 2 are available for most of the period from
March 28, 1970 to August 24, 1971, and ranged
(combined) from 16.3° to 26.9°C (Leming, 1979).
During the period of apparent minimum spawn-
ing, August through November 1970, bottom
temperatures at these sites ranged from 18.3°
to 26.9°C, while during apparent maximum
spawning, March through May 1971, tempera-
tures fluctuated between 16.9° and 22.0°C.
Temi^eratures at Buoys 1 and 2, however, were
recorded in water 18 and 22 m deep, shoaler than
the 28 to 65 m depths where most of the scallops
occur off Cape Canaveral (Allen and Costello,
1972). Therefore, the temperatures at Buoys 1 and
2 often varied from those associated wdth the
large concentrations of scallops in deeper water.
On the shelf off Cape Canaveral there was a
general onshore movement of 18°C bottom water
beginning in March 1971 (Leming, 1979). This
cold water passed over the concentrations of
scallops expected to be mostly ripe during March,
April, and May and perhaps triggered successive
spawning.

DISCUSSION

The spat monitoring techniques used in this
study were useful in determining certain
preliminary information concerning the biology
of the calico scallop. However, ecological succes-
sion and other alterations with time in an ex-
posed spat trap provide a continually changing
environment, affecting both spat setting and sur-
vival. In this low-priority study, the scheduling of
trap exposure was governed by the availability of
ship time. In future studies to measure seasonal
abundance and distribution of spat, monitoring
should be further standardized by scheduling trap
exposure for relatively short time periods of
uniform length and interval throughout the year.
These refinements would also serve to more
precisely fix spawning time and provide measures

118 THE NAUTILUS

October 30. 1979

Vol.94 (4)

of early spat growth by season. Expansion of spat
monitoring over wider areas, both on the Cape
Canaveral grounds and on the Florida-Hatteras
and West Florida shelves, would provide insight
into the origin of the larvae and the relationship
of varying water temperature regimes to spawn-
ing, setting, and survival.

ACKNOWLEDGMENTS

I thank George C. Miller. National Marine
Fisheries Service. Southeast Fisheries Center,
Miami Laboratory, Miami. Florida, for useful
discussions concerning the manuscript, and for
the photograph for Figure 4.

LITERATURE CITED

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Aurelia. M. 1970. The habitats of some subtidal pelecypods in
Harrington Sound, Bermuda. //( Robert N. Ginsburg and
Steven M. Stanley (editors). Reports of research. 1969,
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Belding, D. L. 1910. A report upon the scallop fishery of
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Brown, N. L.. .J. E. Jaeger, F. T. Kleber. and N. F. North.
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Bumpus. D. F. 197.3. A de.scription of the circulation on the
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Caddy. .J. F. 1972. Progressive loss of byssus attachment with
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Calder. D. R. and M. L. Brehmer. 1967. Seasonal occurrence of
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Commercial Fisheries Review. 1962. Calico scallop explora-
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Cory. R. L. 1967. Epifauna of the Patuxent River &tuary.
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Costello, T. .J., J. H. Hudson, ,1. L. Dupuy, and S. Rivkin. 197a
Larval culture of the calico scallop. Argopecten gibbtis.
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Costlow. J. D.. .Jr. (editor). 1969. Proceedings of the Fifth In-
terdisciplinary Conference on Marine Biology. Marine
Biology. 5. Gordon and Breach, Science Publishers. New
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Cummins. R.. Jr. 1971. Calico scallops of the southeastern
United Stotes, 1959^. Natl. Mar. Fish., Spec. Sci. Rep.
Fish. 627. 22 p.

DePalma. J. R. 1969. A study of deep ocean fouling Straits of
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Oceanogr. Office. Washington, DC. Informal Rep. No, 69-22,
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Dix, T. 1977. Life histories of bivalve mollusc larvae.
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Drummond, S. B. 1969. Explorations for calico scallop, Pecten
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Vol.94 (4)

October 30, 1979

THE NAUTILUS 119

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FACTORS INFLUENCING DISTRIBUTION OF MUSSELS IN THE
BLANCO RIVER OF CENTRAL TEXAS

Francis R. Home and Steve Mcintosh

Department of Biology

Southwest Texas State University

San Marcos, Texas 78666, U.S.A.

ABSTRACT

Enr)7-<»}me)ital parameters that influence the di^tnhution of eight mussels in
the Blanco River of Central Texas were studied. Tlie effects of type of substrate,
stream flow rate and physicochemical features on mussel distribution were
evaluated, hut emphasis ivas given to the role of organic enrichment of the river
by a city sewage treatment plant. From tolerance tests to ammonia and low ox-
ygen on five local mussels and from field .studies, the follounng remarks can he
made about mussel distribution in the Blanco River.

(1) Low dissolved o.tygen levels (0 - (1.5 mg (\ l~^j proved lethal to Jt7"/u of the
mwssels tested in seven days.

(2) Levels of .5 mg NH+4 - NH.t' (pH 7.S to H.O: NH, - N = 0.211 mg -1) were
lethal to W% of the mus.sels tested in seven days.

(3) Corbicula manilensis was more tolerant, and Amblema p. plicata less
tolemnt than the other mussels tested to elevated ammonia and low oxygen cim-
centrations associated mth .sewaj/e emichment.

iU) Even though the physicochemical parametets did not indicate stressful condi-
tions on the d,ays sampled, mussels of the Blanco River seemed to have been
adveisely effected by emichment from the secondary sewage treatment plant <f
San Marcos. Fewer mussels were found downstream from the sewage phuit than
upstream, even where the river baftmn. depth, and flow rates ivere similar.

INTRODUCTION

The use of freshwater mussels (Bivalvia) as
aquatic indicators of ecological changes brought
about by agriculture, mining practices, effluents
from industrial and/or domestic disposal plants
has not been studied extensively. Freshwiiter
mussels might be valuable indicatm-s of Ixith |)ast

and present ecological conditions of aquatic en-
vironments.

For the following reasons, mussels might be
especially good as indicators of stream conditions.

(1) Unlike plankton or free swimming fauna,
bivalves as benthic invertebrates usually remain
in relatively fixed positions in streams (Weber
1973).

120 THE NAUTILUS

October W, 1979

Vol.9} (1)

(2) Mussels ain directly alisorb nutrients, sim-
ple orpanic connpounds (Churchill 1916) and
various pollutants. Such pollutants might be
pesticides, radioactive materials and heavy
metals which often would show up in biologically
magnified concentrations (Weber 1973; Butler
1965: Fuller 1974: Bedford et d. 1968; Mathis
and Cummings 1973). Bivalves also indirectly
reflect ecological conditions by taking up
pollutants by feeding from the bjusic trophic
levels or aquatic food chains (Fuller 197 1).

(3) The freshwater mussels (Unionacea) have
relatively long life cycles, up to 17 years and
longer (Williams 1969; Bedford et d. 1968).
Therefore, their community and population struc-
tures are accumulatively affected by environmen-
tal perturbations (Weber 1973).

(4) Unlike periodic chemical analyses, the ben-
thic mussels are continuously exposed, except
when buried, to the water conditions and might
reflect variable or infrequent discharges of
pollutants (Weber 1973).

Our present knowledge is insufficiently
detailed, however, to define Unionaceae or
Sphaeriidae (Pisidiidae) as pollutional indicators
in chemical terms (Fuller 1974; Ingram 1967). A
great deal of work needs to be done on identify-
ing the reactions of bivalves to specific natural
factor's in the environment, and on the reactions
of mollusks to pollutants (Butler 1965).

Recently, Neel and Allen (1964) noted the
decimation of various mussel populations in the
upper Cumberland Basin by coal mine acids,
while Charles (1964) found that very heavy
populations of mussels have been virtually
destroyed by brine pollution from oil wells. Even
potassium has been suggested to regulate the sur-
vival and distribution of freshwater mussels
(Imlay 1973).

Because they concentrate certain pollutants
otherwise not detectable in water or sediments,
mussels have been utilized as indicators of
pesticide and metal pollution (Bedford et d. 1968;
Mathis and Cummings 1973). The bivalves concen-
trated both pesticides and metals in higher con-
centrations than was found in the surrounding
water, but contained lower levels of most of these
toxic compounds than occurred in sediments.
Possibly the best utilization of freshwater
mussels as indicators of stream conditions is as

"indicators of the biological rec-overy zone"
(Simons and Reed 1973).

The purpose of the current study was to explore
the environmental parameters that influence
distribution of mussels in the Blanco River. Special
emphasis was given to the effects of organic enrich-
ment of the river by a city sewage treatment
plant. Tolerance tests to ammonia and low ox-
ygen on five species of local mussels were con-
ducted in the laboratory in an atempt to evaluate
such enrichment.

STUDY AREA

The Blanco River is located at the headwaters
of the Guadalupe River Basin in central Texas.
The Blanco River flows over the Edwards Plateau
and joins the San Marcos River approximately 4
km east of the perimeter of the plateau. The Ed-
wards Plateau is composed of uplifted limestones
that contribute to the natural calcareous hard-
ness of the Blanco River. At the Kyle sampling
station the mean annual flow for a 19 year
sampling period was 4.3 m^ sec"' (U.S.G.S. 1976).
At the Kyle gauging station, about 9 km
upstream from the study area, no flow levels oc-
curred in the summers of 1956, 1963, 19(>4 and
twice in 1971 (U.S.G.S. 1976). Except during
periods of flooding, the lower portion of the
Blanco River is usually transparent enough for a
visual analysis of the substrate.

The drainage basin of the Blanco River above
the Kyle sampling station is 1,(X)7 sq. km. and
contains little arable land. Most of the basin is
sparsely populated, and agriculture consists
mainly of grazing with only limited crop farming
on the rocky terrain. After the Blanco River
leaves the plateau, the river traverses a more
populated area where crop farming predominates.

Sampling areas on the Blanco River were
located between 29°55'— 29°5r latitude and
97°55'— 97°54' longitude. The study area consisted
of a 6 km stretch of the Blanco River located just
upstream of the confluence of the San Marcos
River (Fig. 1). A secondary sewage treatment ef-
fluent enters the Blanco River approximately 2
km downstream from the headwaters of the study
ai^a. The sewage effluent, except under very low
flow conditions, is diluted naturally by a side
channel of the river before it reaches the main
stream. In the faster moving waters of the

Vol.94 (4)

October 30, 1979

THE NAUTILUS 121

FIG. 1. Location of sampling sites on the Blanco River. Texas.

diluted side channel, toxicity study areas were
established about 50 m before and after the point
of entry of the sewage. Three sampling stations
for physicochemical analyses of the river were
located (1) about 50 m above (Station 3), (2) 200
meters (Station 4) and (3) 2 kilometers below
(Station 6) the site where the sewage effluent
enters the river (Fig. 1 ).

METHODS AND MATERIALS
Qualitative and Quantitative Determinations

Qualitative and quantitative mussel counts
were performed at mid-day by visual inspection
while wading or scuba diving in the deeper pools.
The entire study area was quantitatively sampled
for freshwater mussels. Three quantitative counts
were made at stations above, and two quan-
titative counts below the sewage effluent (Fig. 1).
Quantitative counts were made in 10 m^ areas
utilizing ten one meter transects. After identify-

ing and recording the specimens, they were lifted
from the substrate to prevent duplications. Only
those individuals exposed or actively siphoning in
the substrate were utilized in the quantitative
determinations.

Mussel specimen identifications were made
utilizing the taxonomic keys of Burch (1973),
Murray (1%2; 1968), Simpson (1913) and Strecker
(1931). Identifications were checked and verified
by Dr. H. D. Murray of Trinity University in San
Antonio, Texas, and Dr. David Stansbery of Ohio
State University in Columbus, Ohio. Specimen
were deposited at Ohio State University (Collec-
tion Numbers OSUM: 1976: 352-361).

Tolerance Tests

Specimens utilized in the tolerance tests were
collected in central Texas near the study area.
The specimens were then placed in aerated
aquaria for a minimum of five days for acclima-
tion to laboratory conditions. During the period
of acclimation and testing, the experimental and
control specimens were not fed. Before being
utilized in the toxicity tests each laboratory
specimen was washed and scrubbed to remove
adhering organisms. The ventral margins of the
bivalves were notched with a triangular file so
that the bivalves would be constantly exposed to
the stressors. At least eight specimens of each
species were utilized in the toxicity tests.

The chlorine content of the tap water used in
the experiments ranged from 0.2 - 0.4 mg 1"' and
was removed from the test waters by aeration or
bubbling nitrogen. The total alkalinity of the
water varied from 200 to 250 mg 1"' and
depended upon the stressor(s) utilized The total
alkalinity of water from which the organisms
were collected varied from 150 to 200 mg 1"'. The
temperature of the experiments was ambient
room temperature which was usually between
24°— 26° C. The hydrogen ion concentration (pH)
ranged between 7.8 and 8.2 during the laboratory
experiments. At an average pH of 8.0 a solution
containing ammonia (NH-I-4 -NH3) would consist
of 94.7% ammonium ions and 5.3% ammonia gas
(NH3). In this manuscript the term ammonia
refers to both the ionic and gaseous form, even
though the gaseous ammonia is the toxic form.

At no time were moi'e than four larger mussels
used in a single experiment. The bivalves

122 THE NAUTILUS

October 30. 1979

Vol. 94 (4)

Table 1. Substrate related distribution of freshwater mussels in the Blanco River.

Species

Stream Bottom

Boulder

Cobble

Gravel

Pebbles

Sand Silt-mud

Amblema £.
plicata

Anodonta

imbecillis

Corbicula

manilensis

Cyrtonaias

tampicoensis

Lampsilis a.

anodontoides

Lampsilis
bracteata

Quadrula
petrina

Toxolasma

texasensis

+++ = More than S/m^

++ = 1-5/m^

+ = Less than l/m^

- = Not Found

Amblema p. plicata (Say, 1817), Anodonta im-
hecillis (Say, 1829), Corbdcula manilensis (Philip-
pi, 1844), Ci/Honaias tampicnen.'iis (Lea, 1838),
Toxolasma texasensis (Lea, 1857) (^Cairunculina
parva texasensis) were subjected to laboratory
tolerance tests for 168 hours. Specimen were
removed from the testing apparatus after failure
to respond to physical stimuli by closure of the
valves. Death was established when the mussels
did not respond by attempted closure when their
valves were partially pried apart.

Low oxygen tolerance tests (0 - 0..5 mg 0 2 1 '')
were performed in a modified 8 liter desiccator
with a regulated water flow of about 300 ml
hr.''. A 16 liter reservoir of water was deo.x-
ygenated by bubbling prepurified nitrogen gas.
The deoxygenated water was mixed with a
magnetic stirrer and forced through the testing
apparatus with low N2 pressure. Water samples
for chemical analyses were taken from the testing
apparatus by removal and subsequent replace-
ment of standard biochemical oxygen demand
(BOD) bottles that were situated before and after
the specimen container. By maintaining the flow
at least 300 ml hr"' the dissolved oxygen (DO)
levels of the incoming and outflowing waters of
the specimen container were similar.

In the combination high ammonia and low ox-
ygen tolerance tests the water was deoxygenated
first and ammonia then added to the above
testing apparatus. In both the combination high
ammonia-low oxygen and high ammonia
tolerance tests, ammonia levels of 5 ± 0.5 mg 1"'
(NH^ -N = 0.26 mg l"') were obtained by the ad-
dition of ammonium bicabonate. Bunkhalter and
Kaya (1977) estimated 0.25 mg NH^-Nl"' to be
the incipient lethal threshold concentration for
rainbow trout fry.

High ammonia tolerance tests were performed
in 8 liters of aerated tap water in covered
aquaria. Samples for chemical analyses were
made by removal and subsequent replacement of
similar amounts of water from the aquaria.

Tlie tolerance tests in the Blanco River were
performed in a side channel which contained
diluted .sewage. The bivalves Amblema p. plicata,
Anadonta imbecillis. Curbicula manilensis and
Cjfiionaias tampicoensis were put under stress.
The mussels were placed in cages of 1/4 inch
square mesh screen which were partially buried
in the gravel substrate. The controls were located
50 m above the point of entry of the sewage and

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 123

were placed in a similar substrate. The side chan-
nel toxicity tests were performed for one month
periods.

Statistical analyses of the toxicity studies were
performed by single factor analysis of variance
and after hypothesis rejection analyses were
followed by the Student Newman Kuels tests for
differences in population ranges (Zar 1974). The
survival times in hours were used as the observa-
tions in the statistical tests. Since the maximum
utilizable value for sui-vival time was sometimes
limited by the length of the toxicity test, inter-
pretations of the above statistical analyses were
conservative.
Phymcochemical A nalyses

Water samples were taken with 1 liter
polyethylene bottles 0.3 m below the surface on
sunny mid-day periods. Water temperature was
taken at the same time 0.3 m below the surface
in shaded areas. Qilorine levels were determined
in the field. Stream velocities were measured
with a U.S.G.S. Pigmy current meter. Gilorine
levels were determined in the field, whereas
samples for pH, alkalinity, DO, NH+4 -N, BOD5
and total mercury were analyzed wdthin forty-
five minutes of collection in the laboratory.
Samples for the determinations of Kjeldhal
nitrogen, total dissolved phosphate-phosphorus,
and potassium were stored at -20°C and analyses
were conducted within three hours of collection.
Chemical analyses of water were performed ac-
cording to Standard Methods for the Examina-
tion of Water and Wastewater (A.P.H.A. 1975).

Sediment analyses were performed utilizing
the modified Wentworth grade classification
(Home and Mclntyre, 1971 and Weber, 1973). The
substrate was scooped into a container placed
just downstream and analyzed using U.S. Stan-
dard sieves. Hydrogen ion concentrations were
determined with a standardized Beckman Expan-
domatic pH meter. Total alkalinity analyses were
performed by titration with 0.02N H2SO4 to a pH
of 4..5. Dissolved oxygen determinations were per-
formed utilizing the alkali-azide modification of
the Winkler method. Ammonia nitrogen analyses
were made by distillation of the ammonia into
boric acid followed by nesslerization. Kjeldahl
nitrogen determinations were made by sample
digestion followed by distillation and nessleriza-
tion. Total dissolved phosphate-phosphorus

samples were first filtered through 0.45 micron
filters and then treated to persulfate digestion
and the color developed by the ascorbic acid
method. Chlorine levels were determined utilizing
the orthotolidine colorimetric methods. Total
mercury analyses were performed by the cold
vapor technique using a mercuiy analyses system
connected to an atomic absorption spectro-
photometer. Total potassium ion determinations
were made utilizing an atomic absorption spec-
trophotometer.

RESULTS

Qualitative Sampliny and Species Distribution

Living specimens of eight species of freshwater
mussels, and shells of Amdonta g. grandis (Say,
1829) and Lampsilis anodontoides fallaciosa
(Smith, 1899), were collected in the Blanco River
study area (Table 1).

The type of stream bottom and the corre-
sponding flow patterns seemed to limit the
distribution and perhaps the abundance of some
of the species (Table 1). Local geologic formations
(recent alluvium) and periodically high stream
velocities created a bottom composed of a
gravel-cobble substratum in the faster flowing
portions of the stream. Only on the periphery of
the larger pools where the current was slow was
a mud-silt bottom found (Fig. 1). All species col-
lected in the river were present, although
sometimes sparsely, in mud-silt substrates.

Individuals having relatively heav>' shells, such
as Quadrula petrina and Amblema p. plicata,
were the only species found in water's with
average stream velocities of 1 m sec"' or greater.
In these waters the bottom was typically com-
posed of cobbles with some boulders and gravel
present. Although Corbicula manilensis has a
relatively thick shell its small size probably
limits it from occurring in the swiftest waters
(Table 1).

Freshwater mussels with shells of intermediate
thickness such as Ciirtonnias tampicoensis. Lamp-
silk a. anodontoides (Lea, 1834) and Lampsilis
bracteata (Gould, 1855) generally were found in
regions of intermediate stream velocities (0.5 - 1
m sec"') where the usual bottom comp<jsition was
coarse and/or medium sized gravel. The very thin
shelled Anodonta imbecillis and the small sized
Toxolusma texasensis were restricted to areas

124 THE NAUTILUS

Octobei- :10, 1979

Vf.l. 94 (4)

with the finast types of substrate material (Table
1). and both were rarely found in the river.

Ph yiiicochemical Parameters

During the sampling period from July, 1976, to
June, 1977, the minimum flow was 1.5 m^ sec"'
and the ma.\imum flow was about 112 m^ sec"' at
the Kyle gauging station. Unlike previous years
very low or no flow periods did not occur during
the sampling year. Water temj^eratures varied
from 11.5°C in January, 1977, to 31.0°C in August,
1976. Secchi disc transparency varied from 0.8 m
to 2.1 m in the Blanco River, (^nerally, trans-
parency increased during low flow periods and
decreased during high flow periods.

The secondary sewage plant adjacent to the
Blanco River usually received less than 30% of
the total sewage load of San Marcos. The mean
flow through the sewage treatment plant for the
twelve month sampling period was 0.84 million
gallons/day (mgd) with extremes of about 0.05 to
1.1 mgd.

For June, 1977, average effluent values for the
treatment plants and the diluted sewage of the
side channel are given in Table 2. Also for June
the sewage enriched side channel of the Blanco
River (Fig. 1) had a total flow of approximately

0.1 m^ sec"' of which about 20 - 50% was sewage
effluent, depending upon the amount of effluent
discharged. During the same period, the Blanco
River received an average of 110 kg BOD, day"',
90 kg potassium day"', 50 kg of ammonia-N day"'
and 9 kg of total phosphate-phosphorus day"' .
The secondary treatment plant received waste
from only the northeast portion of San Marcos.

Total mercury analyses for the sewage effluent
and water samples from the Blanco River in
March, 1977, were below detectable limits (less
than one microgram 1"'). Chlorine also was not
detectable (less than 0.1 mg 1"') in the enriched
side channel. Chemical parameters which were
monitored at Stations 3, 4 and 6 (Fig. 1) are
presented in Table 2. Where the sewage effluent
entered the river, all parameters increased, ex-
cept dissolved ox>'gen and pH. The largest in-
creases occurred with ammonia and total
dissolved phosphate which increased 300% and
100%, respectively. At the sampling station
located 2 km downstream from the treatment
plant (Site 6), all parameters were more similar
to the uncontaminated waters above the sewage
effluent. Only dissolved oxygen returned to its
upstream (Site 3) concentration at the

Table 2.

Water chemistry determinations for the sewage effluent and diluted
sewage in Blanco River side channel.

Parameter (mg 1~1)

Sewage effluent

Side channel
(diluted sewage)

BOD 5

Chlorine

Dissolved oxygen

NH4+NH3-N

pH (units)

Potassium

Total alkalinity

Total dissolved

phosphate-phosphorus

44.20
0.80
6.40

18.40
7.65

33.00

276.00

3.30

9.00
0.00
7.55
6.80
7.85
7.80
240.00
1.70

Vol. 91 (1)

October 30, 1979

THE NAUTILUS 125

Table 3.

Water chemistry determinations for the Blanco River.

Twelve month average (range)

Parameter (mg 1 )

Above
(Site 3)

Below
(Sewage Plant)

Downstreeim
(Site 6)

BOD 5

1.2
(0.9 - 2.2)

1.8
(1.0 - 5.0)

1.6
(1.0 - 2.6)

Dissolved oxygen

8.97
(6.75 - 10.42)

8.79
(6.88 - 10.35)

8.97
(7.42 - 10.37)

NH'!;+NH,-N
4 3

0.03
(0.01 - 0.05)

0.09
(0.01 - 0.27)

0.06
(0.01 - 0.14)

Organic - N

0.24
(0.09 - 0.36)

0.38
(0.09 - 0.63)

0.36
(0.08 - 0.49)

Potassium

2.06
(1.70 - 2.70)

2.27
(1.85 - 2.85)

2.48
(1.85 - 2.78)

pH (units)

7.88
(7.74 - 8.02)

7.87
(7.74 - 8.02)

7.89
(7.75 - 8.02)

Total alkalinity

193 OO
(165 - 212)

197.00
(170 - 224)

196.00

(170 - 224)

Total dissolved

phosphate-phosphorus

0.12
(0.04 - 0.26)

0.24
(0.05 - 0.49)

0.22
(0.04 - 0.72)

downstream station (Site 6). The nutrient levels
of ammonia-N best indicated the enrichment of
the sewage effluent upon the Blanco River (Table
3).

Tolerance Tests

The laboratory tolerance tests were chosen
because they measured parameters that were
potentially toxic to freshwater mussels and which
may result from organic enrichment. Since the
laboratory tests lasted only seven days, highly
stressful conditions were needed for definitive
results. Nevertheless, the concentrations chosen
were environmentally realistic. During the labor-
atory tolerance tests, it was frequently observed
that the more tolerant species had their shells
tightly shut, while the least tolerant species
usually continued siphoning or had their mantles
exposed.

Tlie exotic asiatic clam (Corhicula manilensis)
demonstrated greatest survival to low oxygen
conditions (Table 4). The native mussels, Amxlon-
ta imhecillis and ToXDlasmn texaserms, also had
relatively high survival capacities to low
dissolved oxygen, whereas Cyrtonauu^ tampicoen-
sLs and Amblema p. plicata had the lowest sur-
vival tolerances. Amblema p. plicata had a

significantly lower survival tolerance to low
dissolved oxygen (Table 5). Although the four
other species exhibited large differences in their
survival capacities (Table 4), they were not
significantly different at 95% confidence limits
(Tables).

TdXdlasma texxmensi^ demonstrated the highest
survival capacity during the aerated high am-
monia tests (Table 6), whereas Arwdonta im-
beciUis and Amblema p. plicata had the lowest
tolerance to high ammonia concentrations. Due to
their frequent gaping, snapping of valves and ex-
trusion of glochidia when gravid, Anodnnta im-
becillis appeared to be the most stressed species.
All species frequently secreted mucous at the
beginning of the aerated ammonia experiments.
The interspecific survival capacities were not
statistically different at 95% confidence limits for
the mussels in high ammonia (Table 5).

In the combination high ammonia— low oxygen
tolerance tests, Corbicula manilensis again
demonstrated the highest survivorship (Table 7).
No apparent synergistic effects were detected in
the combination high ammonia— low dissolved ox-
ygen tests. Interspecifically, Amblema p. plicata
had significantly lower survival tolerance and
Corhicvla manilensis had significantly higher

126 THE NAUTILUS

October 30. 1979

Vol. 94 (4)

tolerance as compared to mast of the other
species (Table 5).

Survival of the mussels, e.xcept Corbinda
manilensnn in the combination low o.xygen— high
ammonia tests, appeared to be related to the
mussel's tolerance to one of the two most .stress-
ful parameters. Intraspecfic suiTival capacities in
the laboratory tolerance tests were not signifi-
cantly different at the 95% confidence limit.

The tolerance tests in diluted sewage again
demonstrated that Corbicula manilensis had
significantly higher survival capacities (Table 5
and 8). Amhlema p. plicutu had significantly
lower tolerance to the diluted sewage, while
Criitonnkui tnmpicoemis and Anodonta imbecillis
exhibited intermediate survival capacities that
were not significantly different from each other.

The levels of potential toxicants in the sewage
side channel are given in Table 2. Ammonia and
{wssible potassium were found at ptjtentially
lethal concentrations. However, the measured
daylight and nocturnal oxygen levels did not ap-
pear near the lethal range nor potentially
stressful during the tolerance tests. Although low-
oxygen levels may not have been present in the
sewage side channel (Table 2), the relative
tolerance of the mussels was comparable to their
.survival capacities in the combination low o.xygen
—high ammonia tolerance tests (Tables .5, 7 and
8).

Quantitative Samples

Quantitative sampling sites were chosen in
areas with similar substrates at mid-stream loca-
tions in both the slow and fast moving waters.
The substrate composition shown in Table 9 is
from faster moving waters (0.3 - 1.5 m deep), but
even at the sampling stations in the slower mov-
ing waters (1 - 4 m deep) more than 90% of the
substrate was composed of fine gravel or larger.
All quantitative sampling sites were located in
areas containing relatively high populations of
freshwater mussels. Therefore, data presented in
Table 10 is representative of the more dense
mus.sel populations of the Blanco River. Marked
differences were noted in the number of species
and the populations of mussels above and below
the point of entry of the sewage effluent (Table
10). Initially during the study period large
numbers of mussels were found in the river im-
mediately below the sewage effluent (Fig. 1). At
the end of the study period in July, 1977, very
few mussels were found alive at this site. The
large numbers of mussels initially found in the
uppermost portion of the enriched study area
may have been transported by floods from a large
bed of mussels found just upstream at Site 3 (Fig.
1).

Of the native species. Amblema p. plicata and
Qumlnda petrina were the most abundant. The
asiatic clam (Corhicida manilensis) was not

Table 4. Percentage survival in low oxygen concentrations (0-0.5 mg O^ 1 ■'■) .

Species (Number used)

55 hr

110 hr

165 hr

Amblema p. plicata

Anodonta imbecillis

Corbicula manilensis

Cyrtonaias tampicoensis

Toxolasma texasensis (8

88

100

100

88

100

88

89

62

88

75

89

38

62

Vol. m (I)

October 30, 1979

THE NAUTILUS 127

Table 5.

Statistical analyses of tolerance tests (SNK) for interspecific mean
survival times.

Species

Low 0-)

Tolerance Test

High NH3

Low O2 + High NH3

Diluted Sewage

1) Amblema p.
plicata

2) Anodonta

irabeci His

-S(all)

+3(1)

3) Corbicula

manilensis +S(1)

4) Cyrtonaias

tampicoensis +S(1)

5) Toxolasma

texasensis +S(1)

NS

NS

NS

NS

NS

-S(3,4,5)

-S(all)

-3(3)

+ 3(1)
-3(3)

+3(1,2,5)

+S(all)

+S(1)
-S(3)

+3(1)
-S(3)

+3(1)
-S(3)

3 = Significantly different at 95% confidence interval (-3 = lower; +3 = higher).
NS = Not significantly different at 95% confidence interval.

noticeably present in the study area in the spring
or summer of 1976. However, immature Corbinda
manilensis were found about 7 km upstream of
the study area in the spring of 1976. Immature
specimens were first evident in the study area in
the spring of 1977. Corbicula manilensis was
found in much higher concentrations above the
sewage effluent than given in Table 9. Densities
of up to 50 m"^ of small individuals were found in
the uncontaminated headwaters of the Blanco
River side channel (Fig. 1). The highest numbers
of Corbicula manilensis occurred in sand-fine
gravel substrates. No living specimens of Cor-
bicula manilensis were found below the entrance
of the sewage effluent in the Blanco River.

DISCUSSION

From the previous records of Strecker (1931)
all of the species collected in the present study,
except the exotic asiatic clam (Corbicula manilen-
sis), have been present in the Guadalupe River
drainage for many years. Since Lainpsilis
bracteata is still present in the Guadalupe and
San Antonio River drainages, and Quadrula
aurea (Lea, 1859) is also present in the
Guadalupe River drainage, the continued ex-
istence of these species may not be threatened.

Athearn (1970) has considered both Lampsilis
bracteata and Quadrula aurea as rare and en-
dangered in central Texas.

Some species of mussels are limited in their
distribution by the type of stream bottom. For
example, mussels of the genus Anodonta and Lep-
todea fragilis were only rarely found in rocky
substrates (Murray and Leonard, 1962). In the
Blanco River Anodonta imbecillis and other
species with relatively thin, light weight shells
did not occur in swift waters with coarse
substrates. This might be due, in part, to their
physical displacement and/or destruction by the
shearing forces in faster waters.

Considering the rapid dissemination and
population growth of Corbicula manilensis. their
abundance in the upper half of the study area in
1977 was not suprising even though none were
noted in 1976. Gardner et al. (1976) observed that
the population of Corbicula manilensis in the
Altamaha River (Georgia) increased from a
minimum of 0/m^ in 1971 to a maximum of
10,000/m^ in 1974. Corbicula manilensis main-
tains a distinctive reproductive advantage over
the usually dioecious, slow growing, glochidial-
producing native freshwater mussels. Corbicida is

128 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

monoecious, incubates its free-living larvae and is
sexually mature in less than one year (Gardner
et al. 1976).

The physicochemical parameters measured
from July, 1976, to June, 1977, for the Blanco
River were similar to those found from other
parts of the Guadalupe River drainage (Hannan
et al. 1973; Young et al. 1972). The large in-
creases of ammonia-N (300%) below the point of
entrance of the sewage effluent into the river
suggested organic enrichment of the stream. Am-
monia values often are a good index of changes in
trophic status of streams that have been in-
fluenced by excessive enrichment by organic
wastes (Ellis 1937).

Although pronounced changes in the water
chemistry were found below the point of entrance
of sewage effluent into the river, none of the
parameters measured were at concentrations
known to be toxic or harmful to freshwater
mussels. Upon consideration of the sources of
waste entering the secondary treatment plant, ex-
cessive pollution by heavy metals or pesticides
was not likely. The lack of measurable flow in
the Blanco River as reported by the Kyle gauging
station during previous dry periods (U.S.G.S.
1976), however, could increase the levels of poten-
tial toxicants to concentrations equal to or
greater than the levels found in the diluted
sewage side channel. When the Blanco River
stops flowing, as it does every few years, the

sewage is not diluted when it enters the river
and is then the primary source of water below
the sewage plant.

The levels of ammonia-N, potassium and noc-
turnal dissolved oxygen could be potential
hazards for the mussels during such low flow
periods. Imlay (1973) found potassium levels of 11
ppm to be toxic in 36-52 days to 90% of the
freshwater mussels tested, and for long term sur-
vival. Imlay (1973) postulated that potassium
levels should be no higher than 4 to 10 mg T'. It
is doubtful that potassium would be a problem in
the Blanco River. In contrast, it is well known
that nocturnal dissolved oxygen deficiencies also
can be critical in determining stream distribution
of organisms (Gaufin and Tarzwell 1952).
Organically rich pools or slow moving waters in
the Blanco River might experience extreme fluc-
tuation in O2 concentration, especially at the
mud-water interface. Cx)nsidering the levels of
potential toxicants (ammonia, low O2 and
potassium) in the Blanco River, as demonstrated
by their values in the diluted sewage side chan-
nel, ammonia is probably the most lethal stressor
to mussels during the low flow periods.

The depletion of dissolved oxygen that results
from sewage enrichment has been proposed as the
principle stressor influencing molluscan survival
(Ingram 1957). Ellis (1937) stated that juvenile
mussels are very sensitive to low oxygen concen-
trations and that adults usually become quiescent

Table 6.

Percentage survival in high ammonia (5 mg NH +NH -N)

4 3

Species (Number used)

55 hr

110 hr

165 hr

Amblema £. plicata

( 9)

78

56

33

Anodonta imbecillis ( 9)

100

67

56

Corbicula manilensis (14)

100

95

62

Cyrtonaias tampicoensis (10)

100

100

70

Toxolasma texasensis (10)

100

80

80

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 129

Table 7. Percentage survival in low oxygen and high anunonia

i -
3

(0-0.5 rag O2 1~ + 5 mg NH>NH^-N)

Species (Number Used)

55 hr

110 hr

165 hr

Arnbleraa p. plicata

( 8)

100

25

Anodonta imbecillis

(12)

60

40

Corbicula manilensis

(16)

100

93

93

Cyrtonaias tampicoensis (10)

80

60

Toxolasma texasensis

(10)

90

20

when oxygen levels are at or below 20% satura-
tion. However, mussels generally are more
tolerant of low O2 levels than freshwater fishes.
One of the more tolerant of the freshwater fishes,
the carp, survives only a short time in water con-
taining 0.71 mg O2 1'. In contrast, in the low O2
tolerance tests (0 - 0.5 mg O2 1"') about 53% of
the mussels tested in this study survived for
seven days (Table 4).

During the laboratory tolerance tests, the
mussels that did not have their valves closed for
extended periods were more senstive to stressors
(NH3 and/or low O2). A similar conclusion was
made by Ellis (1937), who reported that if
mussels failed to respond by shell closure to low

dissolved oxygen, then they were more vulnerable
to destruction by pollution. Extended gaping of
the valves usually precluded death. In the
laboratory tolerance tests when a mussel began
to gap its valves, death would usually follow
within several hours.

Mussels that were stressed usually siphoned
less and had their valves closed for longer periods
than the non-stressed specimens. Badman (1975)
noted that under hypoxic conditions, Elliptio
dilatatus and Pleurobema cocdneum increased
periods of valve closure and reduced filtration
rates, whereas in contrast, Allen (1923) reported
widening of the siphons and mantles to pass more
water through the mussel (increased respiration)

Table 8. Percentage survival to diluted sewage in the Blanco River side channel.

Species (Number Used)

7 days 14 days

21 days

28 days

Amblema p. plicata

(16)

12

Anodonta imbecillis (10)

70

20

Corbicula manilensis (20)

100

65

50

50

Cyrtonaias tampicoensis (11)

64

27

130 THE NAUTILUS

October 30, 1979

Vol.94 (4)

Table 9. Substrate composition of two typical collecting areas.

Type

U.S. Series No.

Size (mm)

Percent
Upstream

Composition

Downstream

Boulder

-

256

-

-

Cobble

-

64-256

49.10

20.90

Coarse gravel

-

32-64

11.50

26.10

Medium gravel

-

8-32

24.60

36.50

Fine gravel

8

2-8

12.30

13.00

Very coarse sand

18

1-2

1.80

1.50

Coarse sand

40

0.5-1

0.62

1.54

Medium sand

60

0.25-0.5

0.02

0.32

Fine sand

120

0.125-0.25

0.04

0.10

as a result of low oxygen levels. The various
species may respond differently to environmental
stressors.

The mussels most tolerant of low dissolved ox-
ygen were collected from standing or slow mov-
ing waters. For example, the more tolerant
Anndonta imbecillvi and Toxolasma texasensw
were taken from ponds or reservoirs, while the
more sensitive Amblema p. piicata was collected
in the fast moving waters of the Blanco River. At
least for some mussels, tolerance to low dissolved
oxygen levels might be correlated with distribu-
tion.

Insufficient dissolved oxygen was suggested by
Isom (1971) as a cause for the decline of the
endemic mussel fauna in Fort Loudoun Reser-
voir, Tennessee. Organic enrichment of the reser-
voir was apparently the causative agent.

Perhaps even the rapid colonization of aquatic
habitats by Corhkula manilensis is due to their
tolerance to stressful physicochemical conditions
as well as their reproductive capabilities. Hable
(1970) found that Corhkula was resistant to low
oxygen levels and that the presence of Anodonta
imheciltia and Corhicula manilensi.'i in Fort Lou-
doun Reservoir, when they had not been

previously detected in the Tennessee River, may
have been -due not only to their fecundity, but
also to their relative high tolerance to low
dissolved oxygen. As with Corbicida maniletisis,
Anodonta imbedllis is monoecious and has
glochidia that may develop to maturity without a
living host (Murray and Leonard 1962).

The lack of significant differences in survival
capacities to elevated ammonia levels
demonstrated that of the mussels tested, all are
relatively sensitive to ammonia. In aerated
aquaria, where the pH of the testing waters
varied from 7.8 to 8.2 and was similar to the pH
of the Blanco River, concentrations of 5 mg
ammonia-N 1' were lethal to 40% of the
mussels tested in seven days (Table 6). The am-
monium ion (NH,) is not very toxic, but molec-
ular NHj is highly toxic. The proportion of
ammonia to ammonium ions greatly increases
with decreasing hydrogen ion concentrations, and
as reported by Ellis (1937), pH is an important
factor in the toxicity of ammonium compounds to
aquatic animals. For instance, Ellis (1937) found
that for daphnia and gammarids, the toxicity of
ammonium compounds increased 200% or more
as pH increased from 7.4 to 8.0.

Vol. 94 (4)

October 30. 1979

THE NAUTILUS 131

With concentrations of 6.8 mg ammonia-N 1'
(pH 7.85), the diluted sewage in the side channel
contained ammonium levels which exceeded the
experimental ammonium levels utilized in the
laboratory. The concentrations of 18.4 mg
ammonia-N 1"' in the sewage effluent would pre-
sent potentially lethal levels if the effluent com-
posed 20% or more of the total stream flow. Such
conditions would exist in the Blanco River if the
flow was reduced to about 0.1 m^ sec"' which
would be 15 times lower than the minimum flow
(1.5m ' sec-') found for 1976-1977.

Over long periods, much lower concentrations
of ammonia may be detrimental to mussels. Ellis
(1937) found that 1.5 mg ammonia 1' was the
maximal concentration not indicative of organic
pollution. In streams mth pH values ranging
from 7.4 to 8.5, ammonia levels of 2.5 mg 1'
would tend to be detrimental to many freshwater
animals (Ellis 1937). Levels of ammonia-N prob-
ably should be kept below 1 ppm in all streams
containing mussel populations.

Mussels are more sensitive to ammonia than
the common goldfish, Carassiiis auratus. which
Ellis (1937) listed as tolerant to 10 ppm am-
monium carbonate (pH 7.7) for more than four
days. Conversely, and as mentioned earlier,

physiologically mussels are less sensitive to low
dissolved oxygen levels than goldfish. However, a
mussel's chances for survival when unfavorable
conditions occur is reduced by their lack of
mobility and confinement to the substratum.
Ma.ximum allowable ammonia-N levels in a
fishery is 0.02 mg l"' (Wellingham, 1973; NAS
and NAE, 1972).

In general, laboratory tolerance tests
demonstrated that Corbicula manilensis was the
least, and Amblema p. plicata the most sensitive
of the mussels (Table 5). However, not all
Amblema can be called "sensitive". On the basis
of their high densities in "conditionally polluted
areas", Richardson (1928) postulated a species of
Amblema (A. mtiplicata) to be the least sensitive
of the mussels sampled in the Illinois River.

Since specimens for this study were collected
by handpicking, the youngest age classes of
mussels were not observed. Mussels less than
three years of age are commonly overlooked when
handpicking (Van Cleave 1940). No information,
therefore, was collected on mussel reproduction
when exposed to the stressors or on larval
tolerances. It is likely that individuals of the
same species, but of different ages, have
dissimilar tolerances to stream pollutants (Ellis

Table 10. Quantitative samples of the freshwater mussels of the Blanco River.

Species

Upstream (ic/m^)

Site 1 Site 2

Site 3

Downstream (x/m2)

Site 5 Site 6

Amblema p.
plicata

2.7

6.8

5.7

0.0

0.1

Corbicula

manilensis

1.6

0.0

1.6

0.0

0.0

Cyrtonaias

tampicoensis

0.0

0.6

0.0

0.0

0.0

Lamps ills a.
anodontoides

0.1

0.0

0.0

0.0

0.0

Lamps ills
bracteata

0.1

0.0

0.1

0.0

0.0

Quadrula
petrina

0.2

0.5

1.3

0.0

0.1

132 THE NAUTILUS

October 30. 1979

Vol.94 (4)

1937). Pollution tolerance data, therefore, must be
viewed with caution.

Based upon the results of this study the sug-
gestion by Weber (1970) that Corbicnla is less
tolerant than Anodonta imbecillis to organic
pollution may be incorrect.

Due to the intolerance of mussels to diluted
sewage in the side channel and because the
substrate and other physical factors below the ef-
fluent of the treatment plant of San Marcos are
basically similar to those factors upstream, the
decreased number of mussels downstream was
probably due to organic enrichment (Fig. 10). The
severity of sewage pollution would increase
tremendously during low or no flow periods. No
other explanation is available at present to ac-
count for the disproportionate lack of mussels
below the entrance of the sewage effluent in the
Blanco River.

Simons and Reed (1975) noted that the
molluscan segment (mostly mussels) of the ben-
thic community represented a more sensitive por-
tion of the macrobenthos than did most insects in
the North Anna River, Virginia. The point of full
"biological recovery" of the North Anna River
was assumed to have been where the mussel
populations had been reestablished (Simons and
Reed 1975).

As suggested by Ingram (1957) and from data
presented here, mussels may have value as in-
dicators of nonpolluted waters because their
presence typically indicates high dissolved oxygen
and associated chemical and physical conditions.
For determination of the severity of water pollu-
tion reduced numbers of "clean water" species
which were formerly present in the stream may
be more important than an abundance of known
pollution resistant forms (Richardson 1928).

The following concluding remarks can be made
from the tolerance tests and field studies.

(1) Low dissolved oxygen levels (0 - 0.5 mg Oj
1') proved lethal to 47% of the mussels tested in
seven days.

(2) Levels of 5 mg NHVNHj 1"' (pH 7.S to
8.0 were lethal to 40% of the mussels tested in
seven days.

(3) Even in waters with dissolved oxygen levels
not indicative of pollution, ammonia levels can be
lethal to mussels.

(4) Corbicula manilensis is generally more

tolerant and Amblema p. pHcata less tolerant
than the other mussels tested to stressors
associated with sewage enrichment.

(5) Even though the physicochemical
parameters did not indicate stressful conditions
on the days sampled, mussels of the Blanco River
seemed to have been adversely affected by enrich-
ment from the secondary sewage treatment plant
of San Marcos. Fewer mussels were found
downstream from the sewage plant than
upstream.

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Englewood Cliffs, N.J. 622pp.

Prentice-Hall,

ALLOCATION OF "MARGINELLA " CORDEROI CARCELLES, 1953
TO A NEW GENUS IN THE VOLUTE SUBFAMILY ODONTOCYMBIOLINAE

(GASTROPODA)

Miguel A. Klappenbach

Museo Nacional de Historia Natural
Montevideo, Uruguay

Marginella corderoi was described and il-
lustrated by Carcelles (1953:10, pi. III. fig. 17, 18)
as coming from places located in the South
American Atlantic littoral, at the mouth of the
Rio de la Plata. The description as well as the il-
lustrations, left us with a certain doubt about the

correct allocation of the species in the genus
Maryiiiella.

Subsequently we examined the holotype
(M.A.C.N. "Bernardino Rivadavia" N° 24194)
coming to the conclusion that what we really had
was a Volutidae, without being able, though, to

134 THE NAUTILUS

October 30. 1979

Vol.94 (4)

determine the genus for lack of knowledge of the
soft parts. Rios (1970:112) also expressed his
doubts about it, placing the generic name in
quotation marks and stating that it did not look
like A Marginella.

Recently we have obtained on the shore of the
Brasilian State of Rio Grande Do Sul (a3°17'S
-.50°34'W Operation CEDIP II, 10-20-72, in a thin
muddy bottom) some specimens of the above men-
tioned species with its soft parts (Col. Male.
M.N.H.N. N° 8809). We then prepared the radula
and verified that the species belonged to the sub-
family Odontocymbiolinae (Clench & Turner, 1964:
170). The radula is formed by a single row of
rachidian teeth and each one of them is made
up of a basal plate forming a medium angle (Fig.
2) from which a long, narrow, curved, hook-
shaped tricuspid emerges. This characteristic, the
large protoconch and the proportionally short
spire, allow us to place this species close to Odan-
tocymbiola Clench & Turner, 1964.

Nevertheless, the details of the sculpture, axial-
ly ribbed, crossed by thinner spiral cords clearly
separate it from this genus. However, this
sculpture is a characteristic of Miomelon philip-
piana (Dall, 1890) type-species of the genus
Miomelon (Dall, 1907:365). But the latter presents
a high spire and very small protoconch with a
rachidian tooth formed by a basal plate, roughly
rectangular, and no angle in the middle portion
(Pilsbry & Olsson 1954:pl. 27, fig. 10) (Stuardo &

FIG. 1. Minicymbiola (new genus) corderoi (Carcelles. lH.'i.l).
Tj/pe <if Ihe genii.s. PiimtiflM' specimen No. ■U9J,, Malaciilayical
Collection, Museo Nacional de Hiitoria Natural . Montevideo.
200km west of Urug-uay in loometers.

Villarroel, 1974:14.5, fig. 17); these features do not
agree with the species of Carcelles.

For the above reasons, we think that it would
be convenient to establish a new genus for the
species with the following diagnosis:

Minicymbiola gen. nnv.

Type-Species: Manjinelln corderoi Carcelles,
195-3

Dicujiiosis: Shell small within the subfamily.
The largest specimen we know is 28 mm in length
(N° 11.430 of the Collection Museo Oceanografico
de Rio Grande, Brazil) and it was obtained in
Uruguayan waters 3.5°05'S and 52°40'W, 117 m
in depth. Spire short; protoconch moderately large
and dome-shaped. Axial sculpture formed by
rounded ribs crossed by thinner spiral cords.
Radula with arched basal plate forming an angle
at its middle part and bearing three long, narrow
and curved cusps. Periostracum and operculum
are absent.

Distribution: At present, represented only by
the type-species which is found in the South
American Atlantic from the State of Parana,
Brazil, in the North. (Rios, 1970:112) to the Pro-
vincia of Buenos Aires, Republica Argentina, in
the South.

Remarks: The subfamily Odontocymbiolinae,
Clench & Turner, 1964, contains five genera: Odon-
tocymbiola Clench & Turner, 1964; Miomelon
Dail, 1907; Tractolira Dall, 1896; Volutoconm
Crosse. 1871; and now Minicifmbivla. The only
known living species of Tractolira are from
Pacific waters, off Central America, in abyssal
depths. The protoconch forms an apical spur
that characterizes them easily.

Vdlutoconiis has four species restricted to
Australian watei-s. In this genus the protoconch
bears an apical spur, and other features are pre-
sent that allow us to separate it from the genera
known to South American waters (Atlantic or
Pacific). A second species, represented only by
the holotype up to now. from a locality between
the Malvinas Islands and Magailanes, Miomelon
ticoresbyana Powell, 1951, possibly should be
removed from this genus when its radula is
known and placed in Minici/mbiola. Its short
spire, stump-shaped apex, and its sculpture con-
sisting of very weak axial lines of growth
(Weaver & du Pont, 1970: pi. .56, E.F.) similar to

Vol.94 (4)

October 30, 1979

THE NAUTILUS 135

the ones found in Odontoritmhiola pescalia Clench
& Turner, 1964, or in young specimens of Odon-
tocymhiola magellanica (Gmelin, 1791) indicate
its affinity with Odontoci/mbiola and separate it
from Mianielon.

Finally, we have the genus Odontoci/mbinla
Clench & Turner, 1964, which contains four
species living in South American Atlantic waters:
0. ainericuna (Reeve, 1856), 0. mmiclUtnicn
(Gmelin, 1791), 0. pescalia Clench & Turner, 1964
and 0. sHb)i()d()>in (Leach, 1814): the last one was
included in the genus recently by Weaver & du
Pont (1970:130) and by Castellanos (1970:2). The
last three species present a characteristic unit
that gives homogeneity to the gi"oup. This is not
the case with 0. americana (Reeve, 1856) also
considered to be in the genus: but its smaller
size, smooth e.xterior surface and rather sharp
nodes separate it from the former ones. We
should emphasize that Clench & Turner (1964:
129) stated that the characteristics of the shell of
0. americana (Reeve, 1856) are closest to the ones
of AulJcirm vespertilio (Linn^, 17.58) from the
West Pacific, but the radulae are different, plac-
ing the species in different subfamilies.

In short, it appears to be logical to include the
new genus Minicymbiola in the subfamily Odon-
tocymbiolinae based on the radular char-
acteristics. Also it appears as a very distinct
genus easily separated from Odontocifm^iola by
its small size and conspicuous a.xial sculpture and
its spire. It is easily distinguished from Miomdan
by its short spire, large and stump-shaped apex
and by the conformation of the basal plate of the
rachidian tooth.

The name Minicymbiola cnrderni (Carcelles,
1953) should not be confused with another volute,
Ffovocator corderoi Carcelles, 1947, an entirely
different species.

FIG. 2. Twd rachidian radulae of Minicymbiola corderoi
(Carcelles. 195S). from a specimen off Rio Grande Do Sul.
Brasil.

LITERATURE CITED

Castellanos. A. A. de. 1970. Reubicaci(5'n de algunas especies de

Volutidae del Mar Argentine, Neotropica, 16(49): 1-4, La

Plata. Argentina.
Carcelles. A. 19.5.3. Nuevas especies de Gastropodos Marines de

las Republicas Oriental del Uruguay y Argentina. Com.

Zool. Mus. Hist. Nat. Montevideo, 4(70): 1-16. pis, 1-.5.
Clench, W. J. & Turner, R. D. 1964. The Subfamilies

Volutinae, Zidoninae, Odontocymbiolinae and Calliotectinae

in the Western Atlantic. Johnsonia, 4(4.3): 129-180. pis.

80-114.
Dall, W. H. 1907. A Review of the American Volutidae.

Smith. Misc. Coll.. 48:341-37.3.
Pilsbry, H. A. & Olsson. A. A. 19.54. Systems of the Volutidae,

Bull Amer. Paleont. 35(152):27.5-306. pis. 25-28.
Rios, E. C. Coastal Brazilian Seashells, 1-255, pis. 1-60. 4 maps.

Rio Grande. Brazil.
Stuardo. .J. & Villarroel. M. 1974. On Some Living and Fossil

Volutes Referred to Miomelon Dall. 1907 and Proscaphella

von Ihering. 1907, Tlie Veliger. 17(2):139-1.5.5. 21 figs.
Weaver, C. S. & du Pont, .J. E. 1970. The Living Volutes,

Monograph Ser. 1. Delaware Mus. Nat. Hist. I-XV. 1-.375,

pis. 1-79.

136 THE NAUTILUS

October 3n. 1979

Vol. 94 (4)

LOCALIZED EGG SHELL DISSOLUTION DURING DEVELOPMENT IN
STENOTREMA LEAI (PULMONATA: POLYGYRIDAE)

Alex S. Tompa

Museum of Z<)olop\-

University of Michigan

Ann Arbor, Michigan 48109

ABSTRACT
As the embryo of Stenotrema leal (Binney) undergoes development, it first dis-
solves the calcite ai/stnls in the mder part of the egg, not uniformly throughout
the surface of the egg, but at a local area of the shell. Fiimlly the rest of the egg
shell calcium crystals are dissolved. This observation is at odds with previous ex-
pl/ui(tti<i)is of egg shell dissolution only by lowering egg albumen pH. Now it seems
that some larval organ is specifically applied against the egg shell and causes local
calcium resorption in one area at a time The two mx>st likely organs which could
be involved are the embryonic podocyst, which is a modification of the foot, or the
mouth region.

Recent work has clearly demonstrated that the
egg shell of most land snails contains calcium
carbonate crystals which the embryo utilizes for
its own calcium needs during development (Tom-
pa, 1975). Almost all the work pertaining to such
embryonic calcium utilization has involved eggs
which are said to be heavily calcified (Tompa,
1974), i. e., they have a brittle, hard calcium shell.
In such a system, using the eggs of Strophocheilus
oblongus, it has been shown that the egg fluid pH
dramatically decreases and fluid calcium concen-
tration concomitantly increases during develop-
ment (Tompa, 1979). Because of this documenta-
tion, it appeared that all of the egg shell calcium
must be dissolved at the same rate, equally all
around the egg, since a pH decrease in the egg
albumen fluid would cause erosion everywhere
where it touches the egg shell. The present study
deals with changes associated with development
in the partly calcified egg of the land snail
Stenotrema leai (Binney) (alias monodon (Rac-
kett)). This study suggests that a pH change in
the egg albumen is not sufficient by itself to ex-
plain the differential disappearance of calcite
crystals in the outer egg layers in partly calcified
eggs.

MATERIALS AND METHODS

Stenotrema leai snails were collected within
the city limits of Ann Arbor, Michigan. They
were brought into the laboratory, fed on a diet of
carrots, chalk and filter paper, and were found to
mate and breed successfully. Containers were

checked for eggs every day; when found, they
were immediately isolated and placed inside a
small glass Petri dish containing ash-free filter
paper moistened with deionized water. Qose-up
photographs were periodically made of the
developing eggs.

RESULTS

A total of ten clutches were examined. The
number of eggs per clutch was 2.06 ± 1.06, with
each clutch ranging in size from 1-4 eggs. The
average size of the eggs laid was 2.28 ± 0.14 X
2.29 ± .18 mm. Approximate time of hatching at
20°C was two weeks. The pictures illustrated in
Figure 1 were taken from eggs of the same
clutch, in increasing order of age, so that Figure
1 is a newly deposited egg, while Figure 4 is
within a few days of hatching.

The most striking aspect of this developmental
sequence is that the egg crystals are not dissolved
uniformly around the embryo. Instead, certain
areas of the shell are preferentially dissolved,
often completely, before other parts of the calcite
layer were involved. Figure 2 is an especially
striking example of this phenomenon, where one
small area of the egg shell has been completely
denuded of calcite crystals while the rest seem
intact. As indicated in Figure 4, most eggs lose
their opacity by the time of hatching, and become
transparent from loss of the crystal layers in the
outer egg shell. This same type of localized calcite
dissolution has been subsequently observed with

Vol.94 (4)

October 30. 1979

THE NAUTILUS 137

^^^HHlTj

^^^^^^^^^^

^^H^^^M

FIGS. 1-4 Illustrate the appearance of prugresmvely older eggs
of Stenotrema leai during incubation at room temperature.
1, is a freshly deposited egg: 2, is older by several days and
shows a single prnnounced area of crystal dissolution: 3, is
older still, with a more extensive area of calcium, carbonate
erosion. 4, is an egg only a few days from the time of
hatching: here the embryo occupies most of the egg and only
a very snudl amount of caleite crystal material is left. This.
too, will disappear before final hatching. White scale bar in
the upper right comer indicates 0.5 mm. All four eggs are
from the same clutch: i is the maximum number of eggs
found per chdch for this species in the laboratory.

eggs of other partly calcified eggs, such as those
of the pulmonates, Varohadra yeppoonensis from
Australia and Helicodiscus parallelus from the
northern United States.

act site of caleite disappearance. Especially in
the earlier parts of development, the egg is
opaque and the embryo is not visible. Presently,
the best guess is that either 1) the embryonic foot
organ called the podocyst (see Gather and Tompa,
1972) is applied to this area to dissolve calcium
carbonate, or that 2) the mouth and its secretions
are directly responsible. We know that im-
mediately post-hatching, the neonate consumes
all of the egg shell remnants available and may
even rasp on the shells of other nearby eggs
(numerous sources; personal observations with
such snails as Helix, Stenotrema, Anguispira,
etc.). On the other hand, it is also known that the
podocyst, an embryonic organ modified from the
foot, functions in taking up egg albumen (Gather
and Tompa, 1972) and indeed it may have a
calcium resorbing function as well, such as in the
avian embryo's chorioallantois (Terepka et ai,
1969). This is all the more likely since the
podocyst is often seen directly appressed to the
inner egg shell surface for long periods of time.
The podocyst is often so large in later develop-
ment that it makes direct contact with 50% or
more of the inner surface area of the egg shell.
Therefore, either the podocyst or the larval
mouth area takes part in egg shell caleite resorp-
tion. The embryo, of course, needs this calcium to
build its first whorls of the body shell, the pro-
toconch, so that it has a hard shell by the time of
hatching (Tompa, 1975). No doubt, such a hard
shell, into which the neonate can withdraw, has a
direct and immediate selective advantage where
micropredators abound; the calcific egg shell is
dissolved, then re-precipitated by the embryo as
aragonite body shell crystals.

DISGUSSION

The cause of such specific and localized caleite
dissolution is not clear and conflicts with the
previously held ideas that a general erosion of
the egg shell crystals occurs during development.
The present study suggests that while there may
be a moderate degree of general crystal dissolu-
tion during development, limited areas are
preferentially attacked and rapidly dissolved.

It has not been possible to associate the jux-
taposition of any embryonic organ with the ex-

LITERATURE GITED

Gather. J. and A. Tompa 1972. The podocy-st in pulmonale
evolution. jV/a/ar. Rev. 5:1-3.

Terepka. A., M. Stewart and N. Merkel 1969. Transport func-
tions of the chick chorioallantoic membrane. II. Active
calcium transport, in vitro. Expt. Cell Res. 58:107-117.

Tompa. A. 1974. The structure of calcareous snail eggs. Malac.
flpr. 7:49-50.

197.5. Embryonic use of egg shell calcium in a

gastropod. Nature 255:232-33.

1979. pH and calcium concentration changes in a

molluscan egg during development. Experientia. 35:812-813.

138 THE NAUTILUS October 30. 1979 Vol.94 (1)

GASTROPODS AS INDICATORS OF TROPHIC LAKE STAGES

Arthur H. Clarke

Smithsonian Institution
Washington. D.C. 20560

ABSTRACT

Field data associated with the 91 species and subspecies of boreal and arctic
North American freshwater gastropods were analyzed. Most species and subspecies
are eurytopic, but a few are entirely, or nearly, restricted to lakes of particular
trophic levels. These are: Valvata sincera sincera Say for oligotrophic lakes.
Fossaria decampi fStreng) and Stagnicola catascopium (Say) for oligotrophic and
mesotrophic lakes, and Amnicola limosa (Say). L\Tnnaea stagnalis juguiaris (Say),
and Planurbula armigera (Say) for eutrophic lakes. Physa integra Haldeman is fre-
quently associated unth mesotrophic lakes but also occurs in other habitats. The
indicator species are illustrated and briefly described.

The literature dealing with gastropods as in-
dicators of water quality, especially in regard to
water pollution, has been recently reviewed by
Hannan (1974). That paper includes a survey of
existing knowledge (including new observations)
about the tolerances of many species of
gastropods to extremes of pH, alkalinity, total
CO2. dissolved O2, and temperature, and to in-
dustrial wastes and pesticides. The fundamental
value of this approach is unquestioned, although
as that author has also pointed out, most
moUusks have broad tolerances for environmental
perturbations and "almost every common species
has been found in polluted environments" (loc cit.
p. 302.)

The present study seeks to assess the possible
utility of freshwater gastropods, not as pollution
indicators, but as indicators of progressive
ti'ophic lake stages. It is based on the literature
and on about 2000 freshwater field collections
and associated observations made since 1950
throughout cool-temperate, boreal, and arctic
North America (Clarke, 1973. 1980). Although the
field experience has been fairly extensive, in most
instances the trophic character of a lake was
judged solely on qualitative observations. The
conclusions presented here must therefore be con-
sidered provisional. Most freshwater species listed
here are eurytopic or wide-ranging in habitat
tolerance, but others are restricted to lakes in
various stages of development.

Of course mollusks have biological require-
ments which affect their utility as indicator
organisms. Since most pulmonates are ranfined to

shallow water where access to the atmosphere is
possible, they commonly occur near the water
line or among emergent vegetation. Many,
however, are apparently able to capture and use
the oxygen released by plants during photosyn-
thesis and in some the pulmonary cavity is filled
with water and functions as a branchium or gill.
Such adapted pulmonates, like prosobranchs. can
thrive in the deep profundal zone of lakes.
Although some species have been found in water
with very low oxygen saturation levels (Harman.
1974), it is unlikely that any species is able to
live for long periods in regions which periodically
undergo prolonged and dra.stic reductions in
dissolved oxygen, such as within the hypolimnia
of many eutrophic lakes. Eggs of gastropods, in
fact, ai'e even more susceptible to low oxygen
values.

Table 1 represents a preliminary' attempt to
tabulate the relative abundance, regional geo-
graphical distribution, and kinds of water bodies
inhabited by the freshwater gastropods of
northern North America. The species list is
thought to be complete for Canada and virtually
so for Alaska. Nearly all of the species found in
New England and the states bordering Canada
are also included, and some can serve as laketype
indicators.

The attributes which a species should possess
to be useful as an indicator of lake-stages are:
wide geographical distribution, comparative
abundance, relative stenotopy, and ease of iden-
tification. The table demonstrates that only a few
of the 91 species and subspecies listed combine all

Vol.94 (4)

October 30, 1979

THE NAUTILUS 139

Relative Abundance, Approxlnace Distributions, and Uaual ^j
HablcaCB □( Che Freshwacer Gaattopoda of northern North Aseclca

Lynnaea atkaeoals Dall
Valvata sincera slncera

Valvata perdeprcsaa Walker

Foaaarla decaapl (Streng)

Stagnlcola caataacoplua
catascopluB (Say)

SCagDlcola keonlcottl Bakei

Phyaa pioplnqua Tryon

Phyaa Jennesal Jenneaal

Dan

Physa hecerostcopha (Say)

Somatogyrus subglobosus
(Say)

Phyaa Integra Kaldeman

Clnclonacla Cincinnati ens I
(Anthony)

Physa gyrina latchfocdl
(Baker)

Hellsona corpulentun
verallionense Baker

Valvata placlnalla (Wilier)

GonlabBBis llvescens
(Henke)

Llthoglyphua vlreos (Lea)

BullBus teotaculatus (L)

Foasaria exigua (Lea)

Physa Jennesst atheaml
Clarke

Physa coluablana Henphlll
Physa lordl Balrd

lellsooa campanulatuit

caatpanuLatun (Say)

Stagnlcols elodea (Say)
Stagnicola proslaa (Lea)
Valvata slncera ontarlenal

Paeudosucclnla colunella
(Say)

Bullmea aegasotsa (Say)

Lymaca scagnalls Jugularts
(Say)

Stagnicola arctlca (Lea)
(^raulua deflectus (Say)

Hcllaoaa trlvolvla trlvolvl
(Say)

H of 55' IE o! 9M'

DISTHIBUTION

OLICOTR KESOTR EUTROPK VERMAL

XXX
XXX

XXX
XXX

XXX
XXX

CAT

: A T B » P

XXX
XXX

XXX
XXX

XXX
XXX

XXX

I'hy.o gyrina gyrlna Say
CytauLus parvus (Say)

I Rafli

Juga pllclfera (Lea)

Canpetoma declsuB (Say)

Vtvlparus georglanus (Lea)

Clpongopaludlna chlnensls
(c:ray)

Harstonla decepca (Baker)

Lyogyrus granun (Say)

Anilcola walkert Pllsbry

Amlcola llaosa (Say)

Foasaria truncatula

(MUller)

Radix aurlculsrla (L)
Radix peregra (Wller)
Acella haldemanl (Blnney)

Armlger crista <L)

(Dall)
KeneCus Cooper 1 Baker
Plsnorbula amlgera (Say)
LaoDia Crlvolvia bioneyl

Phyaa concolor Haldeoan
Physa hordacea Lea
Phyaa nutcalll Lea
Laevapez fuacus (Adams)
FerrlsBla fragllls (Tryoo)
Fossarla madlcells (Say)
naea bulltaoldes

BakerllynmMa dalll (Sakfr)
Stagnicola reflexa (Say)

Gyraulls vennlcularls

(Could)

W of 95* E of 9i' OLICOTR KESOTR EUTROPH VERHAJ,

Fronenetus tnbll

( Cockerel 1)

Icatell

Physa Jennesal sklnoeri

Taylor

Apleia hypnoruB

(L)

Planorbula caope

atrin

DISTRIBUTION

T B H P
T B H P

Stagnicola caperata (Say)

Stagnicola aoatancDals

(Baker)

Phyaa Johnaoni Clench
Ferrlaala rivularla (Sav)
Lonx nuttalli (Haldeman)
Fomatlopsls lapldarla (Say)
Fossarla parva (Lea)

T B C
T B C

XXX

XXX
XXX
XXX

XXX

XXX

XXX

XXX
XXX

XXX
XXX
XXX
XXX
XXX
XXX

XXX
XXX

XXX
XXX

XXX
XXX

id springs
streams and sp -Ings

ant hlbioi
aa{ hlbloi

(1)

Abbreviations. Abumlance: C, abundant or cccraon: R, uncommon op rar«: It recently
introduced (relative abundance unstable). Distribution: A, arctic; T, artic-bore*!
transition zooej B, boreal forest; H, Mstem mountain regioni P, prairie and parkland
region; G, Great Lakes-St. Lawrence forest region. Habitat: X, frequent occurreneej
X, infrequent occurrence.

140 THE NAUTILUS

a-tober 30, 1979

Vol.91 (1)

Apex

[Vnultimatc

Bod\- whorl

OwCTlip

FIG. 1. Part.'! of a gastropod ahell.

of these attributes. These are: (for oligotrophic, or
early stage, lakes)' Valvata sincera sincera Say;
(for both oligotrophic and mesotrophic lakes)
Fossaria decampi (Streng) and Stagnicola
catascopium (Say); and (for eutrophic, or old, ad-
vanced stage, lakes) Amnicola limosa (Say), Lipn-
naea stagnalis jugularis (Say), and Planorbula ar-
migera (Say), among others. In southern Canada
Physa Integra Haldeman occurs most frequently
in mesotrophic lakes and is therefore of some use
as an indicator also, but it is not entirely
restricted to such habitats. It is also worthwhile
to note that Stagnicola caperata (Say) and
Gyraulus circumstriatus (Tryon) are confined to
vernal, or temporary, water bodies and that
Aplexa hypnorum also ordinarily occurs only in
vernal habitats.

The lake-stage indicator species are illustrated
in Fig. 2 and briefly described below. This is for
the benefit of those who are not familiar with
mollusks but who wish to use them for lake
classification. The structural features mentioned
are illustrated in Figure 1. However, positive
identification can only be achieved by considera-
tion of all species which are similar to the in-
dicator species. For additional references consult
especially Baker (1928), Clarke (1973, 1980). Har-
man & Berg (1971), La Rocque (1966-70) and
Taylor (1975).

Prosobranchia

Valvata sincera sincera Say (Valvatidae) (Fig.
2, A) is one of about six boreal North American
species and subspecies of Valvata. It is up to 3.2
mm high and 5 mm wide, with four rounded

' Lymnnra nthaetifix. although known only from oligotrophic
lakes, is restricted to Alaska and extreme northwestern
Canada.

whorls sculptured with widely-spaced coilabral
threads (8 or fewer per mm), and a round oper-
culum with about 6 turns. It is similar to
Valvata .'iincera helicoidm Dall but that sub-
species is more northern, is larger (up to 7 mm
wide) and has finer, more crowded, coilabral
threads (11 or more per mm).

Amnicola limosa (Say) (Hydrobiidae) (Fig. 2, B)
is one of eight boreal North American species in
the family. Most northern hydrobiids are less
than 6 mm high, are higher than wide, and
possess an ovate aperture and an ear-shaped
operculum with fewer than three turns. (One
species, Lyogyrus granum, has a round.

FIG. 2. Trophic take-stage indicator .spprics of gaxtropixlx. A,
Valvata sincera sincera (USNM .i.ma,. width i.ll mm/: B,
Amnicola limosa (USNM 2?109<). height J,.J mm): C, Physa In-
tegra (NMC J.i?J,. height ll.ti mm): D, Fossaria decampi
(NMC S97(ili. height 11.2 mm): E, Lymnaea stagnalis jugularis
(NMC Ii7i9. Iieight 61.1 mm): F, Stagnicola catascopium
catascopium (NMC 2197. height 1S.7 mm): G, J, Planorbula
armigera (NMC 29S19. mdth 6..i mm): H, P. armigera show-
ing position of internal "teeth" (NMC ■i9:lJ,5. width J,.7 mm).
.Abbreviations: USNM. Smith.tonian In.ttitution: NMC. Na-
t iomil Mu.<!eums of Canada.

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 141

multispiral operculum). A. limnsa is up to 4 1/2
mm high, 3 1/3 mm wide, with 4 1/2 convex
whorls, and has a blunt (but not truncated) spire.
It is often abundant on lily pads and other
vegetation. .4. limom occurs throughout the
eastern two-thirds of the United States and
Canada south of the tree-line.

Pulmonata

Fosmria decarnpi (Streng) (Lymnaeidae) (Plate
1, figure D). The Lymnaeidae is a large family
(26 Canadian species and subspecies) char-
acterized by shells which are rather thin, high-
spired, and dextral (i.e. coiled clockwise when
viewed from above) and by the absence of an
operculum. Nearly all Fosmria (6 species in
Canada) are less than 12 mm long at the adult
stage (5-6 whorls) and most are less than 8 mm.
F decarnpi (normally 4-8 mm long and about half
as wide) may be recognized by its shouldered
whorls, laterally flattened body whorl, elevated
and reflected inner lip, and aperture which is
narrowly arched above and broadly rounded
below. It occurs in the Great Lakes-St. Lawrence
drainage and north and west throughout the
boreal forest region, principally in large lakes.

Stagnicola catascopium catascopium (Say)
(Lymnaeidae) (Plate 1. figure F). Most Stagnicola
(10 species and subspecies in Canada) are medium-
sized (10-35 mm), variable, and have relatively
strong shells. S. catascopium catascopimn shows
unusually great interpopulation variability. Most
specimens are between 13 and 25 mm long, about
2/3 as wide, with a rather heavy shell, low spire,
broad aperture, inflated whorls, deep suture, and
thickened inner lip. It occurs across North
America (except in northern British Columbia,
Yukon Territory, and Alaska) south to about
40° north latitude.

Li/mnaea stagnalis jugularis Say (Lymnaeidae)
(Plate 1, figure E) (formerly L. stagnalis appressa
Say) is larger (often 60 mm long), with height
about double the width, up to 7 1/2 whorls, and
thin-shelled. It has a long, narrow spire with con-
cave sides and flatly rounded whorls and a bul-
bous body whorl. This common subspecies lives
throughout nearly all of boreal and temperate
Canada and the northern United States e.xcept
for the extreme eastern portion, i.e. it is absent

from most of New England, the Canadian Mari-
time Provinces, and noithern Quelxx'.

Phym Integra Haldeman (Physidae) (Plate 1,
figure C). The Physidae (about 16 Canadian
species and subspecies) have shells which are thin
in most species, high-spired, and sinistral, i.e.
coiled counterclockwise when viewed from above.
They all lack an operculum and are small to
medium-sized (7-26 mm high). P. integra is up
about 15 mm high, 9 mm wide, with five whorls,
and the shell is thicker and heavier than that of
other northern species of Physa. The aperture is
thickened within by a white ridge and many
specimens have several whiteish collabral bands
representing thickened lips formed during
previous growth stages.

Planorbula armigera Say (Planorbidae) (Plate
1, figure G-J). The Planorbidae (about 21 Cana-
dian species and subspecies) have shells which are
nearly all flatly-coiled, with the body whorl in
about the same plane as the apex, lack an oper-
culum, and may be small to quite large (3-32 mm
in shell width). P. armigera is medium sized
(about 8 mm wide, 3 mm high, 5 whorls) and has
one (rarely two) set of 5, well-developed "teeth"
well within the aperture In most specimens these
teeth may be seen by looking into the aperture
but in some specimens they are visible only by
use of transmitted light (as a dark, thickened
area) or by chipping back about 1/4 of the body
whorl. Only one other northern planorbid, the
larger western species P. campestiis (Dawson),
has apertural teeth but each set contains 6 teeth
and they occur only in juveniles. P. armigera
lives throughout eastern and central North
America from Georgia and Louisiana to New
Brunswick, northern Ontario, and the vicinity of
Great Slave Lake in Canada's Northwest Ter-
ritories.

ACKNOWLEDGMENTS
C. 0. Berg and R. S. Houbrick read the
manuscript and provided u.seful suggestions, Ms.
Cathy Lamb assisted in the laboratory, and Ms.
Valerie Fulford prepared the diagrammatic
drawing. The photographs were provided through
the courtesy of the Smithsonian Institution and
the National Museums of Canada. I am grateful
for all of this assistance.

142 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

REFERENCES

Baker, F. C. 1928. The freshwater Mollusca of Wisconsin. Part
1. Gastropoda. Wiscorusin Academy of Science. Arts, and
Ij-Aters. pp. i-.\x + 1-.507, plates 1-28.

Clarke, A. H. 1973. The freshwater molluscs of the Canadian
Interior Btisin. Malacotoyia 13:1-509.

1980. The freshwater MoUuscs of Canada Na-
tional Museums of Canada. Ottawa (in press).

Harman, W. N. 1974. Snails (Mollusca :Gastropoda) m C. W.
Hart. Jr. and S. L. H. Fuller (Eds.). Pollution Ecology of
Freshwater Invertebrates. Academic Press, New York, N.Y.,
389 pages.

Harman, W. N. and C. 0. Bei^. 1971. The freshwater snails of
Central New York. Search Agriculture. Entomnlogy (Ithaca)
2. Agricultural E^xperiment Station, Cornell University,
Ithaca, NY, pp. 1-68.

Taylor, D. W. 1975. Index and bibliography of Lake Cenozoic
freshwater Mollusca of Western North America. Claude W.
Hibbard Memorial Volume 1, Papers on PaJeontolngy. No.
10. Museum of Paleontology, University of Michigan, Ann
Arbor, 384 pages.

LaRocque, Aurele. 1966-70. Pleistocene Mollusca of Ohio. BulL
Dept. Natural Resources, Ohio 62(M):l-800.

A NEW SPECIES OF AMNICOLA FROM AN ARKANSAS CAVE

(HYDROBIIDAE)

Leslie Hubricht

4026 a5th Street
Meridian, Mississippi 39301

ABSTRACT

A blind cave snail, Amnicola cora, is described from Independence Co., Arkansas.

Amnicola cora, new species

Figs. 1-3

Description: Shell small, broadly conic, wider
than high, thin, subhyaline, pale-yellow; whorls
3.3, well-rounded the last whorl lightly appressed
to the preceding whorl, sutures very deep,
nuclear whorl slightly raised; umbilicus open,
about one-fifth the diameter of the shell; aper-
ture nearly round, peristome continuous, barely
attached to the preceding whorl, lip thin, col-
umellar margin not reflected or bent; sculpture
of many fine spiral lines, operculum comeus,
multispiral, with about 5 whorls.

Animal white and blind, without any trace of
eyes; verge bifid, rather stout; central tooth of
the radula with 11 denticles on the reflection, one
moderately large mesocone and 5 ectocones on
each side; lateral tooth with 11 denticles, one
moderately large mesocone, 3 entocones, and 7 ec-
tocones; marginal teeth with numerous small
denticles.

Height 1.6 mm, diameter 2.0 mm, aperture
height 1.0 mm, aperture width 0.9 mm, umbilicus
diameter 0.4 mm, 3.3 whorls. Holotype.

Distribution: ARKANSAS: Independence Coun-
ty: .stream in Foushee Case, 3 miles west of Locust
Grove (Type Locality) (Norman & Jean Young-

steadt; Leslie Hubricht, collectors) holotype 193762,
and paratypes 193763, Field Museum of Natural
History, other paratypes 47584, 47585, collection of
the author.

Remarks: Amnicola cora is most closely related
to A. stygia Hubricht from cave streams in Perry
Co., Missouri. It differs in being smaller, with
more slowly expanding whorls, the shell is not as
fragile, and the operculum is multispiral rather
than paucispiral. It is named for the Attic god-
dess, Cora, Queen of Hades.

2mm

FIG. 1-3. Amnicola cora Hubricht. holotinw. Fh-nwings courtesy
iif Elisabeth A. Leibman. Field Museum of Nat uraJ History.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 143

THE BEHAVIOR OF THREE SYMPATRIC SPECIES OF CREPIDULA

(GASTROPODA: PROSOBRANCHIA) FROM THE ATLANTIC, WITH

IMPLICATIONS FOR EVOLUTIONARY ECOLOGY

K. Elaine Hoagland

Department of Biology

Lehigh University
Bethlehem, Pa. 18015

ABSTRACT

In the course of a stiuiy of reproductive energetics, behavioral observations were
made on Crepi'dula fomicata (Linnaeus), C. plana Say, and C. convexa Say.
Althoiigh C. convexa is intertidal, C. fomicata and C. plana rarely are. C. fornicata
orients itself on convex, exposed surfaces mth the anterior shell margin upward, if
possible. C. plana is photonegative. C. fomicata and C. convexa juveniles appear at
staggered intervals during the .summer in New England.

When brooding eggs, females of all three species are sedentary. However, all but
the highly convex or tunsted individ^ials are capable of some movement. C. convexa
is the most mobile. Only C. fomicata /orws stacks of more than 3 individuals.

Brooding is energetically costly for Crepidula,' both brood abortion and brood
cannibalism occur. Eggs can also be delayed in hatching. Newly-hatched C. convexa
graze using the radxda; filter-feeding is probably not efficient at that stage.

These behavioral patterns are discussed in terms of their survival advantages
and niche differences of the three sympatric species.

There are three species of Crepidula found
commonly along the eastem coast of the United
States: C. fomicata (Linnaeus), C. convexa Say,
and C. plana Say. The three share several generic
characters of an ecological nature: they are
primarily sedentary as adults, they must copulate
in order to reproduce, they are protandrous, and
they acquire food via filtration of water through
the gills. Species differences include maximum
size, shell convexity, shell muscle scar patterns,
substrate preferences, and whether or not there is
a planktonic larval stage (Hoagland, 1977b). The
species can be collected together at many
localities, including Woods Hole, Massachusetts.

In the course of a comparative study of the
reproductive energetics of the three species
(Hoagland, 1975), behavioral and physiological
differences were identified that give each species
unique niche dimensions (Hoagland, 1978; 1979).
Tiis paper adds further observations on orienta-
tion behavior, brood care, and feeding in
Crepidula. After discussing each set of observa-
tions in turn, I will interpret the findings in the
context of niche theory and evolutionary adapta-

tions for the survival of individuals of each
species.

STUDY SITES, METHODS

Individuals of all three species were observed
in shallow water (less than 1 m) on shell and
stone substrate resting on mud or sand bottom,
at Vineyard Haven (Martha's Vineyard) and
Woods Hole, Massachusetts. Some C. fornicata and
C. plana were found attached to live horseshoe
crabs (Limidus polyphemus). Many C. plana and
C. convexa were on gastropod shells occupied by
hermit crabs, while C. convexa was abundant on
live Littorina littorea. C. fomicata was also
observed on stones in tide pools at Nahant,
Massachusetts, and on Mytilus edulis attached to
docks at Tiverton, Rhode Island.

Some specimens and their substrates were
marked in the field by notching the shell and
painting numbers on the substrate. Laboratory
observations were made on specimens taken from
the Woods Hole and Martha's Vineyard popula-
tions. Live specimens still attached to their
original substrates, or made to attach to watch

144 THP] NAUTILUS

Octobers 1979

Vol.94 (4)

glasses, were maintained in flowing sea water
tables at the Woods Hole Oceanographic Institu-
tion. The temperature was not controlled.

RESULTS: OBSERVATIONS

Microhahitat

Many ecologists describe Crepidula as inter-
tidal. C. convexa occurs on shells of Littonun lit-
torea and Uyanassu obsoleta, snails that frequent-
ly exist intertidally. C. convexa may be found
with a bone-dry shell, tightly affixed to an equal-
ly dry living snail, during the hottest summer
days. Yet C. convexa has been dredged from a
depth of 212 meters (Abbott, 1974).

However, C. fiyniicata and C. plana are uncom-
mon above the mean low tide line. In Nahant, C.
fomicata is found in upper tide pools, but only
occasionally are specimens found out of water. In
Woods Hole, the only specimens of C. fomicata or
r. plana found out of water in three years of
study were those deposited ashore by storms or
by the buoyant alga, Codium fragile, which at-
taches to the shells of C. fomicata and floats the
snails to the intertidal zone. Those C. fn-mcata
and C. plana that attach to the undersides of
horseshoe crabs or inside hermitcrab-occupied
shells also find their way into the intertidal zone,
but remain in a moist environment.

None of the Crepidula are commonly found on
hard substrate in the rocky intertidal zone; this
high energy environment is apparently not suited
to their mode of life, which is much closer to the
oyster than to either the limpet or the mussel.
The preferred substrate of C. fomicata is a con-
vex surface, not highly irregular. Specimens are
rarely found on large boulders, but are common
on fist-sized stones. The bottom sediments are
usually mud rather than sand; the latter in-
dicates an environment that is poor in organic
material and probably in food for filter feeders.
C. fornirata is known for forming large stacks,
one animal atop the other (Figure 1). Occupying
such a convex surface, a C. fomicata individual
would be exposed to greater currents and less
sedimentation than if it were located on a con-
cave surface.

In the laboratory, young specimens of C. for-
ninitd placed inside of finger bowls invariably
climb up and over the edge of the bowl, to the

FIG. 1. A Mfifk of Crepidula fomicata in life position. Sexes
(if the indimlualx are indicated. I = intermediate.

convex exterior. The final orientation is nearly
always as shovm in Figure 2. The animal sits at
an angle to the top of the bowl, with its anterior
shell margin directed upward, near or flush with
the rim of the bowl. Faeces and pseudofaeces are
releiised from the anterior shell margin. Mobile
('. fiirnmiln also tend to move to the part of the
tank with the most rapid water flow.

C. convexa has no preference for convex or con-
cave surfaces, nor does it show precise orienta-
tion. It forms male-female pairs, but not stacks.
It attaches to eelgrass blades as easily as to shells,
bottles, or porcelain (Hoagland, 1977a).

C. plana prefers dark places and concave or
flat surfaces, such as underneath rocks or inside
large empty shells. It forms clusters of several
males and juveniles on one female, but not

FIG. 2. Preferred orientation of Crepidula fornicata on the
iiutxide of a ylaxa fingerhowl. The anterior maiyin touches the
nm of the hold. Die entire bowl wm submeryed in sea miter.

Vol.94 (1)

October 30, 1979

THE NAUTILUS 145

stacks. In the laboratory, C. plana juveniles
display a photonegative response. Natural con-
cave surfaces tend to be inner surfaces, so it is
not clear if C. plana is selecting darkness or con-
cavity or both.

All three species are sometimes found on the
same piece of substrate, such as a stone or a dead
shell. C. plana occupies the under- or inside of
such a substrate, but the microhabitats of C. for-
nicata and C. convexa cannot be so easily
distinguished. In Woods Hole in the years
1972-1974, the summer reproductive periods of C.
foniicata and C. convexa did not coincide. C. for-
nicata spat settled in early June, followed by a
"set" of barnacles; then C. convexa juveniles ap-
peared in early July. Another wave of C. for-
nicata settled in August, and finally more C. con-
vexa in early fall. This pattern serves to decrease
competition among juveniles for substrate. Those
individuals of both C. fomicata and C. convexa
that settled intertidally disappeared within a few
days. This indicates either mortality or removal
to a less exposed microhabitat.

Mobility

The common knowledge among ecologists is
that Crepidula species are largely sedentary. Yet
Crepidula must copulate, and the substrates of
Crepidula are spatially discontinuous; the snails
cannot survive in the intervening sand or mud. C.
fonmata and C. plana can disperse during the
planktonic larval stage, but C. convexa lacks this
stage. I investigated the mobility of the three
species, to see how wide is their access to the
substrate and to each other.

In the field, C. fomicata and C. plana adults
are largely sedentary. Of 50 female C. fonmata
marked in the tidepools of Nahant, 34 remained
in place two years later. C. plana and C. convexa
were more difficult to follow because their
substrates moved. However, C. convexa adults
were observed to travel within tidepools. Those
living on eelgrass either had to move or perish,
because the eelgrass died each winter. The greater
mobility of ('. c(iinr.m. and its greater propensity
for attaching to living organisms, means that C.
convexa is more likely to disperse as an adult
than either of the other species. However, C. con-
vexa, like all other Crepidula, is sedentary when
out of water.

Laboratory observations confirmed the above
impressions. Small individuals of all three
species, including most C. convexa, can maneuver
over abrupt discontinuities in substrate (e.g.,
from one stone to another), across a silty tank
bottom, as long as there is a hard bottom under-
neath. Movement can be assessed by measuring
trails left on the silty bottom. Adult C. fornicata
and C. plana grow to fit the curvature of the
substrate, and have difficulty moving. Highly
arched or distorted specimens cannot move at all.
Regardless of species, those brooding young do
not move.

Both C. fomicata and C. convexa have a
tendency to climb up (negative geotropism) and
out of the water when placed in aquaria. They
often sit above the water line, where they die.
This tendency can be reduced by increasing aera-
tion in the tanks. In fact, several times, young C.
fomicata established themselves directly on top
of an air stone. When aeration in the tanks was
stopped, all but the brooding females and those
attached to other highly arched shells moved up-
ward.

The ability of the three species of Crepidula to
regain their positions on a substrate, once
dislodged, is very different. C convexa can re-
attach within seconds, if both animal and
substrate are wet. C. convexa has a very active
and flexible foot, which allows an overturned
animal to right itself. I have observed C. convexa
floating upside-down on the surface film of the
water until reaching the side of the tank, where
it quickly attached.

Adult C fomicata and C. plana may take 1 to
3 hours to attach firmly to a substrate. During
that time, the specimens are vulnerable to crab
predation. I demonstrated this vulnerability by
placing several adult Crepidula loose on top of
their former substrates, accompanied by 3 crabs,
in an aquarium. All specimens of Crepidula were
eaten.

The difference in ease of attachment between
species is partly, but not completely, due to size.
Small C. fomicata and C. plana can attach more
effectively than larger ones, which often have
irr^ularly-shaped apertures that can only fit
against the substrate on which they grew. Still,
small specimens of C. convexa were more resil-
ient and active than their counterparts.

146 THE NAUTILUS

October 30, 1979

Vol.94 (4)

One cause for mobility in Crepidula is to
enhance breeding success by ensuring copulation.
In both field and laboratory, C. convexa and
C. plana males were seen to wander from one
female to another, although a single pairing of
C. convexa in the lab lasted as long as 5 months.
Some C. fomicata males also wander, but some
spend their entire lives as males with one stack
of females. Most biologists have assumed that
stacking in C. firmicata is related to mating.
Walne (1956) believed that the tendency to form
stacks was not related to reproduction, but rather
to the production of feeding currents. The
strength of the excurrent flow of faeces and
pseudofaeces may be augmented by the shape of
the stack, as Walne supposed. No data exist on
this point. An analogy might be made to oysters,
which form clusters that serve to raise the
animals from a muddy substrate, augmenting
their ability to filter-feed. Yet in Crepidula, the
stack is a breeding unit (Hoagland, 1978), and
probably reduces the vulnerability of males to
predation by reducing their need to be mobile.
Because of the close proximity of the right
anterior portions of the shells of a stack (Figure
1), the several males at the top can easily
copulate with the several females at the bottom,
with eight or more individuals in between. This
leads to a promiscuous breeding system, as is also
found in C. convexa and C. plana, but by means
of an entirely different behavior pattern.

Brood Care

All female Crepidula brooding young are com-
pletely sedentary. Interesting problems for
ecologists include just how much of a liability
this is for a brooding female. How much energy
is expended by a brooding female in caring for
the eggs? Does brooding affect her own chances
for survival?

I observed that females of all three species, but
especially C. fomicata, often push the young out
from under the shell when aeration is reduced,
measurably lowering the oxygen tension in the
aquarium. The same event occurs when the
animals are kept in millipore-filtered sea water
(starvation). In three of eight cases of low oxygen
and two of six cases of starvation, the females
died after expelling the eggs. Survival of females
of equivalent size but not br(x)ding eggs was bet-

ter in all three experimental situations, but in-
sufficient data were obtained for statistical
analysis. The data suggest that there is a cost in-
volved in brooding, and that a female might abort
a bnxjd, thereby increasing her longevity.

Egg masses released by females were kept in
aerated but unfiltered sea water to see if they
would hatch. Ciliated protozoans, bacteria, and
nematodes infested most of the egg masses. If
some of the eggs become inviable, the entire egg
mass eventually was lost to the predators.
However, 2 of 10 ^g masses of C. convexa and 4
of 20 of C fomicata did hatch. The young were
normal in appearance. Therefore, release of the
brood by a dying female could be of benefit to the
young, especially if they were near hatching.

The role of the female in larval brooding thus
appears to be related to oxygenation and cleaning
of the larvae. Egg maintenance appears to re-
quire continuous circulation of water. A female
without eggs reduces its filtration if the water
contains no food, but one brooding eggs continues
to filter at a high rate. This is one energ>' cost.
The brood is maintained in the vicinity of her
gills, which, in these filter-feeders, create strong
currents flowing over the egg mass (Werner,
1951). The presence of the egg mass probably
reduces the efficiency of the gills as respiratory
and feeding structures; this is another cost of
brooding.

Not only can individuals of Crepidula be in-
duced to leave their broods, but they can
sometimes be induced to produce eggs at ab-
normal seasons. In the laboratory, they can also
retain broods over winter, but this has not been
observed in nature, at least in New England
where reproduction normally occurs only in sum-
mer. In New England waters, Crepidula do not
develop broods until the temperature exceeds 10°
C.

Specimens of C. fomicata collected at Martha's
Vineyard in December 1972, were accidently left
outside a water table, in a finger bowl, sometime
between January 18 and February 1, 1973. The
water warmed, and two females produced eggs.
The females with broods were placed back in the
water table, where the water temperature was 2 -
4° C. The egg masses finally hatched on April 1,
1973, at a temperature of 6° C. Another specimen
dredged from Buzzard's Bay, at a time

Vol.94 (4)

October 30, 1979

THE NAUTILUS 147

unrecorded, spawned in a water table on
February 13, 1973, when the water temperature
suddenly rose to 6° C. In the summer of 1972, 25
female C. fomicata were maintained at 9° C, to
see if egg production could be delayed. None pro-
duced eggs at 9° during a three-month period,
June to August, when C. fomicata is normally
brooding.

Specimens taken from Martha's Vineyard in
November, 1972, contained ripe gonads;
specimens taken from the same locality in
January, 1973, had spent gonads, although no
reproduction was observed in the interim. The
gonads are probably resorbed during winter
under natural conditions.

Another question of interest is how long sperm
can be stored within the seminal receptacle of
the female. Coe (1953) claimed that sperm storage
could last several months to a year. In my
laboratory, females of C. fomkata known to have
mated but isolated in early June continued to
reproduce broods through September, but none
reproduced the following spring. This may have
been due to sub-optimal feeding in the
laboratory. Orton (1952) suggested that an in-
dividual could store its own sperm while in the
process of changing sex, thereby functioning as a
self-fertilizing hermaphrodite, but his speculation
was based on the circumstantial evidence of find-
ing isolated females with broods.

Larval Cannibalism

It had been thought that Crepidula under nor-
mal circumstances did not provide the developing
young mth nurse cells (Fretter and Graham,
1962, p. 404-405). However, Gallardo (1977) has
reported nurse cells for Crepidida dilatata, and
Coe (1942), for C onux. Thorson (1940) said that
some capsules of C. walshi contained large em-
bryos, while other embryos in the same capsules
disintegrated.

An examination of several hundred broods
each of C. fomicata and C. convexa within 24
hours of collection in the field revealed that a
high percentage (10% of C. fomicata; 23% of C.
convexa) failed to develop. These embryos broke
up and were ingested by other embryos once they
had reached the stage of possessing feeding struc-
tures. If a normal embryo was artificially rup-
tured with a fine needle, surrounding larvae

spinning around within the egg capsule drew
cells from the damaged embryo into their gullets
via a self-generated feeding current. Both species
did this, but C. convexa appeared not to have the
capability once the larvae had lost the velum. If
the damaged larva is in the veliger stage, the
velum is not eaten but persists within the egg
capsule until the capsule ruptures at hatching.

This process probably explains the cases I have
seen in C. convexa where some hatching egg cap-
sules of a brood contain 8-10 uniform, average
size young, whereas others contain 2-3 very large
young. It explains Thorson 's observation as well.
The size at hatching is more uniform in C. for-
nicata, which releases its brood in the veliger
stage.

Feeding

When the broods are released, C. convexa
young immediately begin a benthic existence. In
the laboratory, I observed one brood of newly
hatched young moving over a glass substrate
coated with bacteria and microscopic algae. The
snails' heads swayed from side to side, clearing
tracks of microorganisms and debris. Inspection
under the dissecting microscope showed that the
odontophores and radulas were working, and
material was entering the guts of the animals.
Putnam (1964) reported that C. adunca also uses
its radula to graze when first emerging from the
egg capsule. Microscopic examination of the gill
filaments of newly hatched C. convexa proved
them to be fewer in number than in adults and
rather fat and club-shaped. It is doubtful that
they could function efficiently as filtering devices
at that stage. This is probably one reason that
Crepidula retains a large, well-developed if
unspecialized radula, despite the filter-feeding
mode.

Another reason for retention of the radula
(over evolutionary time) is that it is used to han-
dle food packaged on the gills (Werner, 1951). I
have observed adults of C. fomicata to reach
around and grab mucous balls containing large
particles rejected by the gills (pseudofaeces),
which normally exit on the right side of the man-
tle cavity. Occasionally, these balls are re-
ingested. This behavioral pattern was observed
only in closed-system aquaria, where I assume
food availability was low.

148 THE NAUTILUS

October 30, 1979

Vol.94 (4)

DISCUSSION
Evolutionary Adaptations

Although cause-and-effect relationships are dif-
ficult to determine in evolutionary biology, one
can often guess the survival value of a particular
behavior or morphological structure. In the case
of Crepidula. it is clear that individual orienta-
tion is adaptive. In C. fomicata, it maximizes the
chances of encountering others of the same
species and maximizes feeding currents while
minimizing fouling. In C. plana, an orientation
opposite to C. fomicata with respect to light
sacrifices availability of currents, but increases
protection against large predators such as crabs
and fish. In C conveia. small size and foot flex-
ibility allow much greater mobility, an obvious
advantage in a species without planktonic larvae.

Brooding costs the female an as-yet undeter-
mined amount of energy. The expulsion of the
broods under conditions of stress benefits the
female by saving energy, and may indirectly
benefit the offspring, which would die if trapped
under a dead female. In terms of evolutionary
theory, this is the optimal strategy for an in-
dividual that has high risk of juvenile mortality,
can produce numerous broods over its lifetime,
and that increases in fecundity with age and size.
The same strategy occurs in birds that abandon
the nest under unfavorable conditions.

The survival advantage of brood cannibalism is
even more obvious. This system prevents wastage
pf the energy that the female diverted into
reproduction. Furthermore, nonviable embryos do
not remain to decay and contaminate the brood.
The "nurse cells" are not specially differentiated
as such, but the effect is the same. Fretter and
Graham (1962, p. 405) described the situation
structurally: "In capsules in which embryos are
not separated from one another but share a com-
mon supply of albumen, it seems likely that a
healthy individual will automatically devour
disintegrating tissues with the albumen which is
used as f(X)d." In terms of evolution, this is a way
of increasing offspring size, as an alternative to
the female adding more yolk to all the eggs. The
advantage of size to a young Crepidula is not
known, but by analogy to other organisms, it
probably provides an edge in survival.

Niche Theory

The three species of Crepidula from New
England are the most divergent, morphologically
and behaviorally, of those living in the Atlantic
Oceaa The differences among sympatric species
in microhabitat, mobility, and orientation
preferences bring up questions about how they
divide their resources (Schoener, 1974). Hoagland
(1976) pointed out that in Crepidula, species with
morphological and ecological parameters in com-
mon overlap only in the tropics where there is
closer species packing. In rigorous environments
such as the northwestern Atlantic, there are
found the fewest species, with the greatest mor-
phological and ecological distance between them.
Important niche-discriminating parameters were
identified as substrate type, light preference,
depth preference, and a size factor, correlated
with types of life history and types of predators.

Carpenter (1857) also demonstrated that the
number of sympatric species of Crepidula, and
the family Calyptraeidae as a whole, decreases
dramatically with increasing latitude along the
west coast of North America. Similarly, in the
Atlantic, those from the northernmost part of the
province have the most extreme differences in
morphology.

Reproductive isolating mechanisms are an
alternative to competition as an explanation for
the observed differences between related species.
However, the need for such mechanisms should
increase in the tropics, and instead, this is the
area with the most similar congeners. I conclude
that the present distribution of Crepidula in the
Northwestern Atlantic and the behavioral dif-
ferences of sympatric species are indicative of
divergence that occurred long ago and had the
effect of decreasing competition.

ACKNOWLEDGMENTS

I thank P. Ander, G. M. Davis, T Schoener,
and R. D. Turner for stimulating discussion of
much of this material. G. Grice provided labora-
tory space at the Woods Hole Oceanographic
Institution. G. M. Davis and R. Robertson read and
commented on the manuscript. This work was
supported in part by a Gibbs Fellowship from
Harvard University.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 149

LITERATURE CITED

Abbott. R. T. 1974. American SeiuihHIx. Second edition. Van

Nostrand. New York. 663 pp.
Carpenter, P. P. 1857. Report on the present state of our

knowledge with regard to the Moliusca of the west coast of

North America. Report of the Brit. Assoc, for the Adv. of

Sci for 1856: 159-368. pis. 6-9.
Coe, W. R. 1942. The reproductive organs of the prosobranch

mollusk Crepidula onyi and their transformation during

the change from male to female phase. Jour, of Morphology

70: .501-512.
1953. Influences of association, isolation, and

nutrition on the sexuality of snails of the genus Crepidida.

Jour, eiper. ZooL 122: 5-19.
Fretter, V. and A. Graham. 1962. British Prosobranch

Molhiscs. their Functional Anatomy and Ecology. Ray

Society, London, xvi + 755 pp.
Gallardo. C. S. 1977. Two modes of development in the mor-

phospecies Crepidula dilatata from Southern Chile. Marine

B>o/(x/.v 39:241-251.
Hoagland, K. E. 1975. Reproductive strategies and evolution

in the genus Crepidula (Gastropoda: Calyptraeidae). Ph.D.
Diss.. Harvard University. 360pp.
1976. Patterns of evolution and niche partitioning

in North American Crepidula (Gastropoda: Calyptraeidae).

A.M.U. Bull, for 1975:b2-^.

1977a. A gastropod color polymorphism: one adap-

. 1977b. Systematic review of fossil and Recent

Crepidula and discussion of evolution of the Calyptraeidae.
Malacologia 16:a53420.

1978. Protandry and the evolution of environ-
mentally-mediated sex change: a study of the Moliusca.
M(U(woiogia 17:365-.391.

. (1979). The behavior and physiology of three

five strategy of phenotypic variation. Biol. Bull. 152:
360-372.

species of Crepidida exposed to a desiccating environment.

Ms submitted to The Veliyer.
Orton. J. H. 1952. Protandry with self-fertilization in the

American slipper limpet Crepidula fomicata. Nature 169:

279-280.
Putnam, D. A. 1964. The dispersal of young of the commensal

gastropod Crepidula adunca from its host Tegula funebralis.

The W/jger6(Suppl.):63-66.
Schoener, T. W. 1974. Resource partitioning in ecological com-
munities. .Sc!>«ff 185:27-.39.
Thorson, G. 1940. Studies on the egg masses and larval

development of Gastropoda from the Iranian Gulf. Danish

sci. Invest. Iran 2:159-238.
Walne, P. R. 1956. The biology and distribution of the slipper

limpet Crepidula fomicata in &sex rivers, with notes on

the distribution of the larger epibenthonic invertebrates.

Pish. Invest. London Ser. II. 20 (6):l-50.
Werner, B. 1951. tiber die Bedeutung der Wasserstrom-

erzeugung und Wasserstromfiltration fur die Nahrungsauf-

nahme der Ortsgebunden Meeresschnecke Crepidula for-

nicata L. (Gastropoda: Prosobranchia). Zool. Anz. 146:97-

113.

THE OCCURRENCE AND SPREAD OF CORBICULA MANILENSIS
IN EAST-CENTRAL ALABAMA

John J. Jenkinson'

Museum of Zoology
Ohio State University
Cblumbus. Ohio 43210

The introduction and spread of the Asiatic
Clam, Corhicvla manilensis (Philippi, 1841)^ in
the United States has been recorded by numerous
authors (review in Sinclair, 1971; Sickel, 1973;
Fuller and Powell, 1973; Diaz. 1974; Britten and
Murphy, 1977). These papers generally include
the type of substrate in which the animals were

' Present address: T.V.A.. Forestry Building, Norris, TN 37828.
' In this paper I am following present usage by considering
C manilensis (Philippi, 1841) to be the name of the eastern
North American corbiculid species. Morrison, however, be-
lieves that the vast majority of these populations are C. leana
Prime, 1864 (J. P. E. Morrison, pe?-.S((«a/ communication. 1977).

found; the range of size classes (often used to
suggest the date of the introduction); some men-
tion of the problems that this exotic bivalve will
cause to human uses of the watercourse; and, oc-
casionally, some hypothesis or comment as to how
Corbicula might have been introduced into the
system. Few of these papers detail the extent of
the newly reported Corbicula population, a fact
which could indicate a great deal about the in-
troduction of this animal into the stream and its
subsequent spread within the system.

Distributional data about previously unre-

m THE NAUTILUS

October 30, 1979

Vol. 94 (4)

ported Corhicula populations were collected while
studying the distribution patterns of unionids in
east-central Alabama (Jenkinson, 1973: 1975).
This study (conducted in 1972 and 1973) involved
four small stream systems, all of which originate
in central Lee County, Alabama. Two of these
streams, Saugahatchee (Saw-ga-hach'-ee) and
Uphapee (You-fap'-ee) creeks, flow west into the
Tallapoosa River while the other two streams,
Halawakee (Hal-a-wok'-ee) and Uchee (Ooch'-ee)
creeks, flow east into the Chattahoochee River
(Fig. 1). During the course of this study 2,646
unionids and 76 voucher specimens of Corhicula
were ajllected from 47 productive sites on these
four streams. Additional collections have also
been made in adjacent small streams and in the
two rivers.

Tlie resulting distribution pattern for Cor-
hicula is illustrated in Figure 1. Corhicula is
abundant in both the Tallapoosa and Chattahoo-
chee rivers (although I had not found it in the
Tallapoosa River in 1968), however, Corhicula is
essentially absent from the tributary streams.

Uchee Creek Population

Two exceptions to this general distribution pat-

tern were found to exist. One large and apparent-
ly well-established population of Corhicula was
located in the lower half of Little Uchee Creek
and in Uchee Creek only below the mouth of Lit-
tle Uchee Creek. No Corhicula specimens were
taken in any other part of this creek system
although unionids were abundant in all of the
peiTTianent streams. The farthest upstream collec-
tion of Corbicula from Little Uchee Creek was
taken at the base of a rapids and falls that mark
the transition from Piedmont to Coastal Plain
substrates. This was also the most upstream site
where fishermen were noticed. Following the
hypothesis advanced by Sickel (1973), it would be
tempting to suggest that Corbicula was in-
troduced into the Uchee Creek system at this site
by fishermen. Unfortunately, I have no additional
evidence to support such a hypothesis.

A similar distribution pattern for Corbicula
has been reported from the Mesilla Valley of
Texas and New Mexico (Metcalf, 1966). In that
case Corbicula occurred in the main channel of
West Drain but not in its tributaries or in any
other adjacent tributary of the Rio Grande River.
Metcalf suggested that the periodic drying up of

FIG. 1. The Icnitwn di.itributinn o/ Corbicula manilensis (Philippi. ISil). in eaxt-fentml Alabama. Most recorxk date from 1972
and 197S: Sauyahaichee Creek records aboxte the mouth of Loblockee Creek date from 12 September 1976.

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 151

the Rio Grande or some adverse environmental
factors in the unpopulated drains might account
for this pattern. Neither of these conditions
seems to be operating in the Uchee Creek system;
the larger streams always maintain some min-
imum flow, and any "adverse environmental fac-
tors" which might prevent colonization by Cor-
bicula have not affected the thriving unionid
populations.

Saugahatchee Creek Population

The Uchee Creek population was the only Cnr-
bicula population known from any of these creek
systems until October 1973, when John C. Hurd
collected one dead specimen of Corbicula in
Saugahatchee Creek. This find was unexpected
because Hurd had surveyed the aquatic mollusks
of western Lee County in 1970-1971 and had
found no living bivalves in the main stream of
Saugahatchee Creek (Hurd, 1971). Hurd had con-
cluded that unionids were unable to survive in
Saugahatchee Creek because this stream carries
the effluents of a large textile mill and a sewage
treatment plant.

In addition to the mill and sewage effluents,
Saugahatchee Creek also receives water from the
experimental ponds of Auburn University
Department of Fisheries and Applied Aquacul-
ture. During the summer of 1972 a project was
conducted in some of these ponds to determine if
Corbicula could be used as a biological filter to
reduce the plankton levels in commercial catfish
ponds. At the end of that project the clay bottoms
of the test ponds were screened in Saugahatchee
Creek to separate out the Corbicula for counting
and growth analysis. The dead specimen that
Hurd collected some distance downstream during
the following fall might have been an escape or a
discard from this screening process. Regardless of
the origin of this specimen, collections made in
November 1973 indicated that living Corbicula
did exist in Saugahatchee Creek at that time.

Starting with the collections made in Novem-
ber 1973, three sites on Saugahatchee Creek have
been sampled at approximately 18-month inter-
vals in an attempt to monitor the status of the
Corbicula population in this stream. The most
upstream of these sites is located appro.ximately
one kilometer above the experimental pond
discharge and the area where the pond bottoms

Ikm, upstream Hm- downstream 10km. downstream

HG. 2. Girbicula ciiUectiim results from three sites an
Saugahatchee Creek taken over a three-year period. Numbers
along each ordiimte refer to maximum shell length in
millimeter's: those along each abscissa refer to numbers of in-
diiiduals with a given shell length.

were screened. The midstream site is approx-
imately one kilometer below the screening site
and the downstream site is approximately nine
kilometers further downstream. In addition to be-
ing visited in November 1973, all three sites were
collected on 8 March 1975 and on 12 September
1976. On each occasion a hand seive was used to
collect Corbicula specimens from sandy areas in
the substrate. No special effort was made to col-
lect particular size classes; what was desired was
an essentially random sample of any living Cor-
bicula population. The results of these collections
and the lengths of the living Corbicula specimens
obtained are shown in Figure 2.

These collections document that during
November 1973 a population of relatively small
(<16mm) Corbicula existed in the creek only at
the midstream collecting site. In March 1975
there were no Corbictda at the upstream site, the
midstream population included some larger in-
dividuals (>20mm) and the downstream site was
populated by many small animals (<12mm). By
September 1976 both the mid- and downstream
sites included animals with fairly broad ranges of
shell lengths, the largest still occurring at the

152 THE NAUTILUS

October 30, 1979

Vol.94 (4)

midstream site. No. Corbicula specimens had yet
been found at the upstream site.

These results strongly suggest that Corhiodn
was introduced into Saugahatchee Creek within
one kilometer of, and within a few months of, the
screening of experimental Corbicula specimens by
Auburn Fisheries personnel. These results docu-
ment that Corbicula was able to survive and
reproduce in a stream which, apparently because
of pollution, is incapable of sustaining unionid
populations. So far as the spread of this Cor-
bicula population is concerned, these results in-
dicate that an easily detectable population was
established approximately ten kilometers down-
stream from the apparent site of introduction in
more than 12, but less than 28 months. The pop-
ulation had not spread one kilometer upstream in
approximately 48 months.

Current

The factors responsible for this apparent
unidirectional colonization pattern are presently
unknown, however, stream current is one en-
vironmental factor which could produce this kind
of effect. According to Sinclair (1971) the North
American corbiculid species passes through a
non -swimming, pelagic, veliger larval stage.
When these larvae are released, they apparently
cannot swam against the current and all of them
are carried downstream. The unidirectional effect
of current alone, therefore, could explain the lack
of upstream colonization in Saugahatchee Creek.

The unidirectional effect of current could also
explain the "unusual" distribution patterns of the
Corbicula populations in the Uchee Creek system
and in Mesilla Valley. In both cases, if Corbicula
had been introduced at an upstream site, the re-
mainder of the distribution pattern coincides ex-
actly with the areas where non-swimming plank-
tonic larvae would be carried by current. In the
Uchee Creek system current would adequately
explain why no Corbicula specimens were found
in Uchee Creek proper above the mouth of Little
Uchee Creek, although unionids occur in both
areas. In Mesilla Valley current alone could pre-
vent an original population in West Drain from
spreading into any tributary that maintained
some minimum flow. This same reasoning could
be used to explain why Corbicula does not occur
in other east-central Alabama streams even

though it is abundant in both the Tallapoosa and
Chattahoochee rivers.

Although this proposed role of current in di-
recting the spread of Corbicula populations would
seem entirely logical and expected, I have found
no mention of it in the extensive American
literature concerning Corbicula. Other ideas have
been advanced, however, to explain the oc-
currence of this invading organism in certain
locations. One recently proposed hypothesis is
that Corbicula sometimes becomes established
because it is able to out-compete the native
bivalves in areas that have been disturbed by
man (Fuller and Imlay, 1976). While this
hypothesis may fit some situations, especially
with regard to sphaeriids (e.g. Gardner et al.,
1976), it does not seem to be operating in the
relatively unaltered Uchee Creek system where
unionids and Coribula occur together in large
numbers. In addition, the information presented
in the abstract by Fuller and Imlay appears to
support this "current hypothesis" better than the
"competition hypothesis" they propose.

Corbicula can no longer be considered to be an
oddity only worthy of a casual distributional
note. This organism is now a dominant member
of many North American freshwater faunas,
often much more abundant than any other mol-
lusk. Since we know so little of the biology,
ecology or taxonomy of this newly-established
species, every piece of factual information which
appears in the literature can only serve to in-
crease our understanding of this animal. In addi-
tion to the theoretical material presented in this
paper. I have attempted to detail the present
distribution pattern of the Corbicula populations
in east-central Alabama as completely as possi-
ble. It is my hope that future workers may be
able to use these data in various ways to increase
our general understanding of this no-longer alien
mollusk.

LITERATURE CITED

Britton. J. C. and C. E. Murphy. 1977. New records and ecolog-
ical notes for Cnrbicida manilensis in Texas. The Nautilus
91:20-23.

Diaz. R. J. 1974. Asiatic Clam, Corhiaila nmnilensii (Philip-
pi), in the tidal James River, Virginia. Chesapeake Sci.
15:118-120.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 153

Fuller. S. L R and M. J. Imlay. 1976. Spatial comix;lilion
between Girbirula manilensis (Philippi). the Chinese Clam
(GirbiculiHae). and freshwater mussels (Unionidae) in the
Waccamaw River basin of the Carolinas (Mollusca;
Bivalvia). .4.s.sor. SmdheaMi'rn Bill Bull. 23:6(1.

Fuller. S. L. H. and C. E. Powell. .Jr. U)73. Range e.xtensions of
Ciirhicula miiiiileiixis (Philippi) in the Atlantic drainage of
the United States. Tlie Naidilii.^ 87:.59.

Gardner, J. A.. Jr., W. R. Woodall, Jr.. A. A. Staats. Jr. and J.
F. Napoli. 1976. The invasion of the Asiatic Clam {Girhicula
manilenxix Philippi) in the Altamaha River, Georgia. Vie
Nautitux9<i:m-125.

Hurd, J. C. 1971. A survey of the mollusks of the Chewacla
and Saugahatchee creek drainages in western Lee County,
Alabama. M. S. Tlirsis. Auburn Univ. 64 pp.

.Jenkin.son. J. J. 1973. Distribution and Z(joge(]graphy of the
Unionidae (Mollusca: Bivalvia) in four creek systems in
east-central Alabama. M. S. Thesix. Auburn Univ. 96 pp.

197.5. The Fall Line as a barrier to the distribu-
tion of some unionids (Bivalvia: Unionidae). Amer.
Mtduadoiiird Union Bull, for 1974::30-31.

Metcalf, A. L. 1966. Corbicula manUemdx in the Mesilla
Valley of Texas ajid New Mexico. Vi.e Nautiiius 80:16-20.

Sickel. .1. B. 1973. A new record of Corbicula manilenxi';
(Philippi) in the Southern Atlantic Slope Region of Georgia.
77ir Av,h/, 7 «.s- 87:11-12.

Sinclair. R. M. 1971. Annotated bibliography on the exotic
bivalve Corbiruln in North America, 1900- 1971. Stirkinnn
43:11-1S.

DESCRIPTIONS OF SIX NEW FORMS' OF FLORIDA TREE SNAILS,

LIGUUS F ASCI AW S

Archie L. Jones

1.37(1 S.W. 1 1th Street
Miami, Floi-ida 33131

In the spring of 1962 I found a group of snail
hammocks in the southern Everglades of Florida
that had never before been explored by Liguus
collectors. One of these supports a polvmorphic
colony of Liguus fnsciatus (Miiller) that includes
two new color forms.

In Pilsbry's (1946) classification of Liguus
fasciatus, these new forms would be placed in the
subspecies testudineus Pilsbry. Their closest rela-
tionship is vfith the form nuitanem. I have called
these two forms, or morphs, humesi and fmmp-
tnni.

Four years earlier (19.58) I had set out with a
friend in his airboat in search of an especially
beautiful form, marrjfioratiis, which a Seminole
Indian, Smallpox Tommy, had shown me. We
picked up Tommy at his camp three miles north
of the Tamiami Trail. A lack of communication
between the Indian and us, or his reluctance to
take us there, prevented us from finding our

' Latinized names for color forms. ./» cm (i, varieties, or aberra-
tions are useful to students of variation, but the.se infrasub-
specific names, proposed after 1%(). have no nomenclatural
standing, and hence no priority over properly proposed sjieci-
fic or subspecific names, according to Articles 1 and 10b of
the International Code Zool. Nomen. - Editor.

marmarntus. The group of hammocks to which he
took us contained instead a new fonn of the
subspecies testvdineus, namely evergiadesensis.

The deplorable practice by collectors of
transplanting the Florida tree snail, Liguiis
/(isciatia^. to hammocks already populated with
other Liguus began before the turn of the last
century and continues to this day. Collectors
gathered choice specimens of this magnificent
snail and put them in selected hammocks with
the e.xpectations of collecting them and their pro-
geny tefore some other collector did. In 1947 I in-
terviewed a Mr. Lincoln, a former Florida West
Coast shell dealer. He was then in his late
eighties and resided in a rest home in Ft. Myers,
Florida. He told me that when he was a young
man he transplanted some Liguus from Long
Pine Key of the Lower Everglades to Big Pine
Key in the Lower Florida Keys. Charles Torrey
Simpson introduced them into his hammock in
Lemon City (North Miami) so that he could more
easily observe and study them. "In my bit of
forest, into which I have carried many specimens
from elsewhere - - -."

A great fluriy of transplantation occurred im-
mediatelv before the establishment of the

154 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

Everglades National Park in 1947. Collectors
rushed to the then-to-be Park and removed some
of the more beautiful varieties and relocated
them outside the Park in Pinecrest, Collier Coun-
ty, the East Coast Ridge and the Florida Keys.
TTiey hid them almost anywhere they thought the
snails would not be found by other collectors.
Tliis distribution in no way hurt the Park col-
onies but the cumulative effect of all the in-
troductions greatly affected the gene mix of once
reasonably stable populations, so that now it
would be next to impossible to work out the
mystery of the distribution of these snails in
southern Florida.

Liginu^ feed upon the minute lichens, fungi,
sooty molds and algae that grow on the bark and
leaves of trees, shrubs, etc. They use their radulae
to scrape these foods and loose particles of bark
from the hammock vegetation. Newly hatched
snails begin feeding at the bases of trees and,
during periods of wet weather, work their way to
the tops of the trees, feeding as they go.

In the descriptions of the forms that follow, I
have used the words large, medium size and sub-
solid in describing the size and solidity of shells.
One should understand that the size and solidity
of Liguus shells are determined to a lesser degree
by heredity and to a greater degree by the
amount and quality of the snail food found in a
hammock. It follows, therefore, that when one
describes the size and thickness of a Liguiis shell,
one describes to a greater degree the condition of
the hammock as it relates to Ligims and to a
lesser degree the inherant nature of the shell
itself. For example: if one took, say, 45 newly
hatched graphicus from one small colony, divided
them equally into three lots and put one lot in a
hammock with a maximum amount of food on
the lysiloma and Jamaica dogwood trees; the sec-
ond group in an identical hammock with a mini-
mum of food; the third lot in a hammock forested
principally with bustic and hackberry with opti-
mum food, one would get three very different
results. If one were to describe the size and
solidity of each group at the end of the third
year of activity, the descriptions would be ap-
proximately as follows:

First group - largesize(up to70mm.), solid;

Second group - small size (up to 46 mm.), thin;

Third group - large size (up to 65 mm.), thin.

These facts were not understood by some describ-
ers of Liguus and it has caused confusion and dif-
ficulty in subsequent identifications of some
forms of snails.

Liguus fasciatus humesi, new form

Figs. .5, 6
Description: Shell medium size (up to 55 mm.
in length), moderately elongate, subsolid; texture
lustrous in young shells to dull in old specimens;
whorls not inflated, slightly convex; columella
sinuate to straight, thin; palatal lip smooth, occa-
sionally crenate at juncture of periostracal green
lines, slightly thickened within.

Color, apex pink; columella and parietal wall
invariably white except in thin shells where the
color of the shell penetrates the very thin white
callus which produces a slight pinkish effect;
there is a narrow white to creamy brown sutural
line; the third whorl is light-pink to brown and is
marked with a few brovm axial striae; the color
of the fourth, fifth, sixth and last whorls is dark-
brown to almost black, broken by irregular
yellowish axial stripes (which are often zigzag)
and blotches that often extend from suture to
suture on the fourth, fifth and sixth whorls and
from suture to the base of the shell on the last
whorl; there is a narrow yellowish peripheral
band that produces a dark band, broken by
yellow axial flames and/or blotches, above and
below the periphery. A small percentage of shells
have a few spiral green lines above and/or below
the periphery.

Type material: The form humeri is found only
in an isolated group of hammocks of the southern
Everglades. The holotype and paratypes were col-
lected March, 1962. The holotype has been placed
in the United States National Museum, Washing-
ton, D.C. It is a four-year-old shell; length 46
mm., width 23 mm., aperture width 23 mm., dis-
tance from suture to base of shell 21.5 mm.
Paratypes have been placed in the United States
National Museum, Washington, D.C, the
Museum of Comparative Zoology, Harvard Uni-
vereity, the Academy of Natural Sciences of
Philadelphia, University of Florida, Gainesville,
and the Everglades National Park Collection.
Homestead, Florida.

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 155

A lot of 129 shells, collected without selection
included the following forms:

castaneozonatus U>1 78%

cingidatus 11 9"/°

humesi 9 7%

fi-amptoni 5 4%

'luteiis 3 2%

129

100%

The color form humeri differs from the form
castaneus by always having a white columella
and parietal wall and by the absence of the single
or double peripheral bands.

In 1964 a group of humesi was introduced into
a hammock containing no Liguus. Since then I
have visited this hammock scores of times during
the last 15 years and have not seen any of the
other forms associated with it in its native
habitat.

It is with great pleasure that I name this shell
for one who has played a significant part in the
history of Ligiuis in Florida, Mr. Ralph Humes,
now of Leesburg, Florida, intimate friend, de-
lightful snailing companion and dedicated conser-
vationist. He donated his fine large Liguus collec-
tion to the Everglades National Park. He is the
originator of the Park Liguus project on which he
collaborated until he moved from Miami. Mr.
Humes described the color form wintei and wrote
a history oi Liguus collecting in Florida.

Liguus fasciatus framptoni, new form
Figs. 7, 8

Dfscriptinn: Shell medium size, (up to .55 mm.
in length), moderately elongate, subsolid; texture
lustrous in young to dull in old shells; whorls not
inflated, slightly convex above the periphery; col-
umella sinuate to straight, thin; palatal lip
smooth, occasionally crenate at juncture of
periostracal green lines, slightly thickened
wathin.

Color: apex pink with a minute brown spot on
its summit: columella and parietal wall in-
variably pink or liver-colored; there is a narrow
creamy brown sutural line; the third whorl is
creamy brown, sometimes with faint narrow light
brown axial streaks; the color of the fourth, fifth,
sixth and seventh whorls is dark-brovm, broken
by irregular yellowish axial striae (which are
often zigzag) and blotches that often extend from
suture to suture on the fourth, fifth and sixth

whorls and from the suture to the base of the
shell on the last whorl; there is a narrow
yellowish peripheral band that produces a dark
band, (sometimes wanting on the last whorl)
broken by yellow axial flames and/or blotches,
above and below the periphery. A small percent-
age of shells have a few faint spiral green lines
above and/or below the periphery. A brovra or
purplish sinuating line borders the parietal wall
from termination of the suture to the tip of the
columella. It is a parallel form to humesi, differ-
ing only in the light -brown coloration, the pink
or liver -colored columella and parietal wall and
the pink apex with the minute brown spot at the
summit.

Type material: This color form is found wath
humesi, castaneozonatus, cingulatus and luteus in
an isolated group of hammocks of the southern
Everglades referred to above in the description of
humesi. The holotype, a three-year-old shell, has
been placed in the United States National Mu-
seum, Washington, D.C. Its length is 47 mm.,
width 23 mm., aperture width 12 mm., distance
from suture to base of shell 21 mm. Paratypes
have been placed in the United States National
Museum, Washington, D.C, the Museum of Com-
parative Zoology, Harvard University, the
Academy of Natural Sciences of Philadelphia,
University of Florida, Gainesville, and the
Everglades National Park Collection, Homestead,
Florida.

The offspring of a number of framptoni in-
troduced several years ago into a hammock
devoid of Liguus were predominately framptoni,
some humesi, luteus and very rarely castaneo-
zonatus.

I have named this form in honor of Henry G.
Frampton (1902 - 1966), one of the early modern
collectors of Florida Liguus, who contributed to
the literature by describing the forms splendidus,
fuscoflammellus and clenchi. His widow,
Theodosia, presented his fine, large Liguus collec-
tion to the Museum of Comparative Zoology, Har-
vard University.

Liguus fasciatus evergladesensis, new form

Figs. 1, 2
De.'icription: Shell medium size, moderately in-
flated, subsolid, texture matt or without much
gloss; whorls convex, last whorl well rounded;

156 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

FIGS. 1-12. Ncir aiUir forma i//' Liguus fascial as (MHJIri) fraiii tin Hunihi Erny(nd(x. Aiicrho-nl ririrs (ire hulnlftixs. dfD-xal
itiews are paralj/pes. 1, 2, evergladesensis. 3, 4, margaretae. .'5, 6, luimesi. 7. 8. fiamptoni. 9, 10. keiiiiethi. 11. 12, beardi. .4//
formae nnvae./(;HP.s. 1.979.

Vol.i»4 (1)

October 30. 1979

THE NAUTILUS 157

sutures not ver>' deep, well shouldered; columella
usually thin, straight and simple, occasionally
slightly sinuated; palatal lip smooth, slightly
crenate at juncture of periostracal green lines,
slightly thickened within.

Gill))-: apex, columella and parietal wall in-
variably pink. Ground color is light-yellow. Tlie
antepenult whorl is marked by a broad smoky
lavender band broken by yellow vertical flames
or blotches. Above and below this band are nar-
row i-ufescent bands. On the penultimate and
body whorls the broad band degenerates into
alternating vertical smoky lavender and light-
yellow flames. The two narrow bands become a
series of comma-like blotches. The yellow ground
color predominates. On the body whorl, the ver-
tical flames are broken at the periphery' by a
very light-yellow band and/or a lavender line.
The columella is bordered by a narrow pink line.
There is a narrow reddish brown basal line which
is often reduced to a series of blotches. Almost all
shells have from one to five spiral green lines
ab(3ve the periphery and from one to four below.

Tifpe material: The type locality is one of a
group of four or five hammocks about one mile
west of Canal Levee 28 about six miles north of
the 40-Mile Bend of the Tamiami Trail. The
holotype has been placed in the United States
National Museum, Washington, D.C. It is a
three-year-old shell: length 48 mm., width 25
mm., aperture width 14 mm., distance from
suture to base of shell 23 mm. Paratypes have
been placed in the United States National
Museum. Museum of Comparative Zoology, Har-
vard University, the Academy of Natural
Sciences of Philadelphia, University of Florida at
Gainesville and the Everglades National Park
Collection, Homestead, Florida.

Comments: Form erergladesensis. in its first
year superficially resembles castanetis but in
later growth the juxtasutural bands are absent or
reduced to a series of blotches. The columella and
parietal wall are invariably pink whereas in most
castaneiis they are white. It is unique among
Pinecrest and Collier County subspecies
testudineus, being the only form having a full
pink tip. I doubt if there is any close genetic rela-
tionship between evergladesenfsis and castanem.
Over 50 miles separate the two forms. The closest
hammocks containing castaneus are those of the

L)ng Pine Key area near Homestead. The form
evergladesensis is found with livingntoni, the
predominant form, and with the form floridanus.
It is interesting that while they are found in a
pol^Tnorphic population they breed true to form
when isolated. Such populations introduced in
two s(juthern Everglades hammocks in 1961 have
never produced any other forms.

Liguus fasciatus margaretae, new form
Figs. .3, 4

Description: Shell large (to 64 mm. in length),
elongate; texture subsolid with a sheen but ap-
pears dull; body whorl convex, well-shouldered;
penultimate whorl convex; the antepenult, fourth
and third whorls flat; columella straight, not
thin, slightly twisted, occasionally obliquely trun-
cated; palatal lip slightly thickened within,
usually crenate at juncture of periostracal green
lines which are numerous and always present.

C(ilo)" columella and first two or three whorls
of spire are white. There is a narrow supra-
sutural creamy yellow band and a subsutural
mahogany-colored line. The fourth whorl is
ivoiy-white broken by reddish brown subsutural
spots that often develop into vertical striae that
extend downward almost to the suture. The fifth,
or antepenult whorl, has a broad bluish gray
band broken by light-tan vertical flares that in-
creasingly diffuse on the penultimate and body
whorls and on the body whorl are overlaid with a
blue-green wash above the reddish mahogany
peripheral line and a wide darker green wash
below the light-tan narrow band that lies im-
mediately below the peripheral line. There is
often a baby-blue line immediately above the
))eripheral line. An orange basal band borders the
columella and it is bordered by a much darker
band that extends from the base of the shell to
approximately two-thirds the distance to the
suture.

Type material: Tlie type locality is a small
hammock of the southern Everglades. The holo-
type is a mature, three-year-old shell, length
.54.5 mm., width 26 mm., aperture width 13 mm.,
distance from suture to base of shell 22.5 mm. It
has been place in the United States National
Museum. Washington. D.C. Paratypes were also
placed there and in the collections of the
Everglades National Park, Homestead. Florida.

158 THE NAUTILUS

October 30. 1979

Vol. 94 (4)

Museum of Comparative Zoology, Harvard Uni-
versity, Academy of Natural Sciences of Phila-
delphia and the University of Florida at Gaines-
ville.

Comments: TTiis race of snails descended from
five snails that appeared in a hammock in which
I had placed together lucidovarim from Pinecrest
Hammock No. 11 and clenchi from Pinecrest
Hammock No. 88. One of these shells had a so-
called "jewel tip", or apex of pinkish brown. This
population produced the two above-mentioned
forms, lossmanicus, many intermediates and the
five ancestors of margaretae.

The five snails were transferred to another
hammock which had no snails. Two years later I
returned and saw about 15 newly hatched snails
(all of the white-tipped form), three white-tipped
parents and the dead jewel-tipped shell. If this
jewel-tipped snail died before it mated it could
account for the white-tipped offspring.

One would expect to find the polymorphism of
the first hammock to show itself in the snail
population of the second hammock but this has
not occurred. Since the introduction in July, 1969
all offspring have been margaretae.

The distinguishing characteristics of
margaretae are the light blue-green wash over
the body whorl and the spire pattern of lucida-
varl'm. In recently collected shells the wash ap-
pears to be more blue than green but as the colors
fade green predominates.

I name this shell for my wife whose patience
and understanding made it possible for me to
spend many thousands of hours in the field these
45 years since I first began snailing in 1934.

Liguus fasciatus beardi, new form
Figs. 11, 12
Description: Shell similar to that of
margaretae, except for color and pattern. First
whorl of spire pink, faintly tinged with brovwi at
the summit. Next two or three whorls ivory-white
or white, sometimes flecked with ochre. There are
supra and subsutural light-brown lines which are
darker, heavier and broken on the antepenult
whorl. On the penultimate whorl this line some-
times appears as brownish spots. The overall m/-
or of the shell is grayish brown wash, broken at
the periphery by a wide, lighter colored band
which is dissected by a heavy, browTi or maho-

gany line. There are usually four or five green
lines above and about three or four brownish
green ones below the peripher\'. The columella is
white or nearly so. The parietal wall is light-
purple. There is a brownish purple line bordering
the parietal wall which extends from the suture
to the tip of the columella. Bordering this line at
the base of the shell is a lighter colored band
sometimes bordered by a darker one.

Tifpe material: The type locality is a small
hammock of the southern Everglades near the
t.\i)e locality of margaretae. The holot\T3e is an
adult three-year-old shell: length 54 mm., width
26 mm., aperture width 14 mm., distance from
suture to base of shell 24 mm. The holotype has
been placed in the United States National
Museum, Washington, D.C. Paratypes have been
placed in the United States National Museum,
the Everglades National Park Collection,
Homestead, Florida, Museum of Comparative
Zoology, Harvard University, Academy of
Natural Sciences of Philadelphia and the Univer-
sity of Florida, Gainesville.

Comments: There is almost a total lack of ver-
tical markings of any sort, except as described
above. Occasionally a shell will have a trace of
the blue-green wash of margaretae on the body
whorl.

It gives me much pleasure to name this shell
for Dan Beard, first superintendent of the
Everglades National Park, whose foresight and
encouragement made possible the introduction of
rare and beautiful forms of Lignus into the Park
where, hopefully, they will be saved for future
generations of scientists to study and for Park
visitors to observe and enjoy.

Liguus fasciatus kennethi, newform

Fi^s. 9.1(1

Description: Shell large (to 62 mm.), moderate-
ly elongate, subsolid to solid, somewhat lustrous
to dull; whorls 7-7':, convex; columella heavy,
straight but slightly twisted, obliquely truncated.

Color: first three whorls of the apex and col-
umella ivory-white, parietal wall veiy light-flesh
color. The ground color of the body whorl is
yellow with an overlay of blotches, smears and
v(>rtical strijies of burnt umber and umber which
fade with time to yellow-ochre. There is a very
narrow yellowish cream subsutural line and a

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 159

narrow (1 - 2 mm.) peripheral band of the same
color, sometimes bordered above by a lavender
line. As the colors fade, each year's markings
become lighter so that in some old shells the
whorls above the body whorl are almost white. A
few specimens show on the body whorls some
spiral bandings as in the form floridanus.
Periostracal green lines seldom present and few
in number. Grovrth-rest varices slightly expanded.

Type material: The type locality is a small
hammock of the southern Everglades. The holo-
type is a four-year-old shell, length 59 mm., width
28 mm., aperture width 15.5 mm., distance from
suture to base of shell 26 mm. The holotype
has been placed in the collection of the United
States National Museum, Washington, D.C.
Paratypes have been placed in the United States
National Museum, the Museum of Comparative
Zoology, Harvard University, the Academy of
Natural Sciences of Philadelphia, University of
Florida, Gainesville, and the Everglades National
Park Collection, Homestead, Florida.

Comments: The progenitors of kennethi first
appeared in Pinecrest Hammock No. 13 into
which Mr. Erwin C. Winte had comingled some
introduced Liguus with the native population.
Unfortunately, no records were kept and in-

formation as to the identity of the forms in-
troduced is uncertain. Mr. Winte and I isolated
five snails of this new form in a barren ham-
mock. Later most of the progeny were transferred
to another hammock. Since then, the two colonies
have remained monomorphic. This phenomenon,
plus the fact that kennethi shows no similarity to
any of the forms of the original population leaves
its geneology uncertain. Its overall shape and ap-
pearance indicate only mainland forms were in-
volved but its somewhat glossy appearance in five
and six-year-old specimens suggests the influence
of a Florida Keys ancestor.

I name this snail for my son whose help in the
exploration for suitable hammocks, collecting
Ligims material and establishing it in the
Everglades National Park contributed substan-
tially to the success of the Park Liguus Project.

LITERATURE CITED

FVampton. Henry G. 19.32. Pr<ic. Biological Society of

Washtngton, DC. 45:55-57.
Humes. Ralph H. 19.54. Go-sCropirfm 1(2):10.

1965. Tequesta, No. 25:67-82.

Pilsbry, Henry A. 1946, Academy of Natural Sciences

Philadelphia. Monographs No. 3. 2(part 1):37-102.
Simpson, Charles T. 1929. Proc. United States
Museum 73(Art. 20):l-44,pls.l-4

of

National

CHICOREUS COSMANI, A NEW MURICID GASTROPOD FROM THE

WEST INDIES

R. Tucker Abbott

American Malacologists, Inc.
Melbourne, Rorida 32901

C. John Finlay

and 116 Tanglewood Lane

Newark, Delaware 19711

Despite the fact that the taxonomy of the fami-
ly Muricidae has recently suffered under the
hands of various conflicting interpretations (E. H.
Vokes, 1971, Radwin and D'Attilio, 1976; Wagner
and Abbott, 1978), new, apparently valid, taxa
continue to come to light (Emerson and D'Attilio,
1979). Contributing to our knowledge of marine
mollusks is a corps of enthusiastic SCUBA divers
and ardent private shell collectors. An outstan-
ding example are the collecting efforts of Mr.
Dieter Cosman of Long Island, New York, who
has personally collected and documented numer-

ous outstanding conchological discoveries in the
tropical Western Hemisphere.

Among Mr. Cosman 's unusual discoveries is a
colony of Chicoreus muricid snails from Jamaica
representing a species which evidently has not
been given a valid, scientific name. We take great
pleasure in naming this new species after him.

Chicoreus cosmani new species

(Figs. 1-9)
Description: Shell moderate in size for the
genus, attaining a length of 79 mm., trigonally

160 THE NAUTILUS

October 30. 1979

Vol. 9-1 (1)

F^KiS. 1-9. Chiaireus cosmani Ahhntt and Finlay. new xpcriem. Orhn Rios. Jiimmcn. 5, in the center is the halatjipe. 7!) mtn. in
Icmjth. the other Jiyurex are ixirntifftesfnim the name locality. Collected by Dieter Coxman. Maivh 1967.

Vol. 91 (1)

October 30. 1979

THE NAUTILUS UH

fusiform in shape. Spire acute, with an angle of
35° to 40°, and about 45 percent of the entire
length of the shell. Nuclear whorls 1 1/2 glossy-
smooth, convex, small but bulbous, whitish to tan,
and with a well-indented suture, followed by S or
9 convex, well-sculptured, p(_)st -nuclear whorls.
First few whorls with a cancellate sculpture be-
tween the varices. Suture finely impressed and
slightly wavy. Aperture relatively small, about
one-fourth the length of the entire shell, and with
the peristome entire. Parietal wall glossy, slightly
raised, and tinted with yellow, orange-brown or
pinkish. Outer lip scalloped and bearing 10 to 12
minute, raised, white denticles. Siphonal canal
moderately broad, nearly sealed, and slightly
recurved dorsally and to the right at the distal
end. Former siphonal canal half as large, tube-
like, recurved to the left, and bearing on its sur-
face a half-dozen axial, irregular, small cords.
Last (and earlier) whorls with three varices,
originating just behind the varix above it on the
previous whoi'l. Each varix in the body whorl
bears 8 short, bi- or tri-furcate, scaly, partially
(or rarely entirely) closed fronds. Tliree of these
fronds are on the right side of the siphonal canal.
In the early whorls the top frond is usally twice
the size of those below. Intervarical sculptui'e
consists of 4, I'arely 3, even-sized axial, low cords
whicli ai'e crossed by numerous finer, spiral
cords, thus foi-ming a pattern of low, rounded
beads, oi- tiny knobs, all about the same size. Col-
or of shell varies from a uniform brownish
orange to a pale yellow orange, rarely white. In-
terior of aperture white, with an orange-stained
columella. Operculum chitinous, light-brown, oval,
unguiculate. with fine, scaly concent ic giviwth
lines.

Measurements (mm)

length

79
67
38
29
2.5

tmdth
(tvith ifpines)
40
.3.3
21
17
1.5

10-F
9-1-
7.5
8.0
7.0

no. whorls

holot)^*. fig. 5.
parat>'pe,fig. 7.
parat.vpe, fig. 6.
paratype, fig. 3.
parat>T)e.fig. 2.

Type Inaditij: on pilings at the Reynolds Baux-
ite dock, Ocho Rios, north side of Jamaica. 10 to
15 feet. March 1967. Dieter Cosman, collector.

Tapes: Tlie holotyi)e (Fig. 5) has been de]>)sited
in the U. S. National Mu.seum no. 78-332.3. Para-

FIGS. 10, 11. Chicoreus species from Curaecu) resemUing
cosmani. 29 mm. in length. Collected by Henk Bielderman,
197-1 CiDistance Boone collection Photos courtesy of Emily
Voke.'>.

types are in the collection of Dieter Cosman, C.
•John Finlay, the Academy of Natural Sciences of
Philadelphia, the Amer. Mus. Nat. Hist., .Jerome
Bijui', and the Delaware Museum of Natural
History. Specimens have been reported as "very
uncommon in about .35 feet at the Bogue Islands,
Discovery Bay, Orange Bay and Bull Bay (ajuth
coast), .Jamaica, in water as deep as 60 feet by
Michael Humfrey (1975, p. 131, pi. 1.5, figs, 10,
10a). We have not seen these specimens. One
paratype (Acad. Nat. Sci. Philadelphia no. 3.5419)
worn in condition, was collected by Robert Swift
in St. Thomas, Virgin Islands, in the 1860's.

Remarks: The Chicoreus complex in the Carib-
bean is complicated by the existence of a number
of species, subspecies and local, isolated forms, so
that the present status of our knowledge is still
far from complete. We believe that C. cosmani is
a valid species, closely related to C. dilectus (A.
Adams, 1855), brevifrons (Lamarck, 1822), spec-
trum (Reeve, 1855) and flurifer (Reeve, 1845). It
differs markedly from those other species in hav-
ing 3 or 4 axial rows of rounded beads between
the varices, somewhat reminiscent of the sculp-
turing seen in Bursa pileare (Linnaeus). The
other species usually have one large and one or
two smaller knobs on the shoulder of the whorl.
In breinfrons and mergus E. Vokes, 1974, the
spire is much lower, the shell more quadrate, and

162 THE NAUTILUS

October 30, 1979

Vol.94 (4)

the upper spine on the varix much larger and
longer than those below. Closest to cosmani is the
specimen from Curacao illustrated and identified
by Ruth Fair (1976, pi. 6, figs. 73, 73a) as
Chicoreus pudoricolor (Reeve, 1845). This may be
a darkly striped, less beaded form of cosmani.
The type and only known specimen of pudoricolor
was returned to Denmark by Reeve, and has not
been subsequently relocated. The original illustra-
tion and description suggests a species more like
corrwgatus (Sowerby, 1841) or a young spectrum.
We consider pudoricolor a species inquirenda.
The Indo-Pacific counterpart of cosmani is
akritos Radwin and D'Attilio, 1976, from north-
ern Australia.

ACKNOWLEDGMENTS
We would like to thank Dieter Cosman for his

generosity in contributing the holotype to the
U. S. National Museum, Smithsonian Institution,

and Jerry Harasewych for his excellent photo-
graphy, and Emily E. Yokes, Constance E. Boone
and the Walter N. Carpenters for information
and the loan of related species.

LITERATURE CITED

E>nerson, W. K. and A. D'Attilio, 1979. Six New Living
Species of Muricacean Gastropods. The Nautilus 93(1):1-10.

Fair, Ruth H. 1976. The Murex Book: An Illustrated
Catalogue of Recent Muricidae. Honolulu, Hawaii. 138 pp.,
363 figs.

Humfrey. Michael. 1975. Sea Shells of the West Indies.
Taplinger Pub. Co.. NY. 3.51 pp.. 32 pis.

Radwin, George E. and Anthony D'Attilio. 1976. Murex Shells
of the World. An Rlustraied Guide to the Muricidae. Stan-
ford Univ. Press. 284 pp., 32 pis.

■Vokes, Emily H. 1971. Catalogue of the Genus Murex Linne;
Muricinae, Ocenebrinae. Bu/i Amer. Paleont. 61(268):1-141.

Wagner, R. J. L. and R. T. Abbott. 1978. Standard Catalog of
Shells Supplement I pp. 13-801 - 13-810. American
Malacologists, Melbourne, FL.

POPULATION DYNAMICS AND ZONATION IN THE PERIWINKLE
SNAIL, LITTORINA ANGULIFERA, OF THE TAMPA BAY,

FLORIDA, REGION

Susan B. Gallagher

12250 6th Street East
Treasure Island. FL 33706

and

St

George K. Reid

Eckerd College
Petersburg, FL 33733

ABSTRACT
Seasonal changes in population density and size class distribution reflect the
seasonal nature of reproduction in Littorina angulifera in the Tampa Bay. Florida,
area The zonation pattern of adult snails and juveniles is described. Both extreme-
ly high tides and a Gymnodinium breve "Red Tide" bloom reduced the population
density. The Gymnodinium bloom killed new recruits differentially and had a
long-lasting effect on the population density. The data show that most new
recmits reach spawning size 9 to 10 months after metamorphosis. Most adults do
not survive to spawn after two years, as there is an approximate 70 percent yearly
mortality.

INTRODUCTION
This is our second report dealing with Lit-
torina angulifera (Lamarck) in the Tampa Bay

area. The first dealt with reproductive behavior
and early development (Gallagher and Reid,
1974); this report characterizes the composition

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 163

and zonation of a Tampa Bay population of L.
angulifera and describes seasonal changes in it
from October 1971 through May 1975. In addition,
two unusual natural environmental stresses oc-
curred during the course of the study. Excessively
high tides three to five feet above normal (Simon,
1974), accompanied Hurricane Agnes in June
1972 and an extensive outbreak of "red tide"
caused by blooms of the dinoflagellate, Gipn-
rmdinium breve, in the winter and spring 1974.
Effects of these events are described and resul-
tant changes compared with those in non-stress
years.

Although various Ldttorina species have been
investigated extensively, only Borkowski (1974)
has studied seasonal population changes and
growth in groups of littorines over a period of
several years. Palant and Fishelson (1968)
reported on the reproductive cycles and ecology
of L. punctata and L. neritoides in the Mediterra-
nean Sea, but seasonal changes in population
density and size distribution were not considered.
Lenderking (1954), in her work on the biology of
L. angulifera in the Miami, Florida, area studied
growth, reproduction and size distribution pat-
terns, but data were sparse on small snails
because they were difficult to detect in the
mangrove habitat in which she worked. Popula-
tion density studies were not done. Hayes (1929)

and Moore (1937) investigated shell growth in L.
littorea; Moore also reported on spawning, length
of life and mortality in this snail. Bingham (1972)
investigated the growth and ecology of L. irrorata
but none of these studies investigated seasonal
changes in snail populations as reported here.
Much has been done also on zonation patterns of
littorines by Smith and Newell (1954), Evans
(1965), Bock and Johnson (1967) and Chow (1975)
among others. In addition to studies involving on-
ly littorines, others have investigated desiccation,
temperature and salinity changes, and behavior
patterns in relation to observed zonation patterns
of intertidal animals generally (Broekhuysen,
1939; Kensler, 1967; Markel, 1971; and Vermeij,
1972). There are very few investigations en-
compassing the complete life history of pro-
sobranch mollusks done in such a way that life
cycles of the species can be illustrated from one
spawning season to the next and so related to
seasonal changes in population density and size
distribution (however, see Frank, 1965). Results
reported here, coupled with those obtained in a
previous study on reproductive behavior (Gal-
lagher and Reid, 1974) depict events in the life
history of this snail, but we do not attempt to
analyze the factors, whether physiological or en-
vironmental which may be causal in these events.

160-

"o

^ 140

O
ID

20--

(VJ

100- -

\r-^

\

i ^•^■

\ t^

Hurricane Agnes

.-^ Area A
— -o Areo B

Q z o

no*

1971 1972 1973 1974 I97S

FIG. 1. Fluftuations }n population density o/Littorina angulifera /rom October 1971 through May 1975 in two areas of seaivall.
Except for the large differences in recruitment in the fall of 1971 the populations densities in the two areas were similar.

\M THK NAUTILUS

October 30. 1979

Vol. 91 (1)

TAXONOMIC NOTE
There is some question regarding the tax-
onoinic status of this snail. Rosewater (1963)
stated that it was a subspecies of the Indo-Pacific
snail Littorina scahra and so should be called L.
Hcuhra (DH/nlifpra. It was so called in our first
report (Oallagher and Reid, 1974). However.
Bandel (1974), in his study of Atlantic Lit-
torinidae. more recently stated that radular dif-
ferences between the two are such that they
should be considered separate species. Because of
this and because Abbott (1974) also considers
these two as separate species, this animal is so
considered in this report. Until this taxonomic
problem is cleared up we believe it less confusing
to refer to the organism as L. an(julifera since it
is so designated in most of the literature.

HABITAT
Most of the animals in this study occupied a
vertical concrete seawall bordering a canal in
Boca Ciega Bay immediately south of John's Pass
in Treasure Island, Florida (27°47'N, 82°47'W).
The seawall habitat was chosen because of the
ease of observing and counting animals on it in

contrast to attempts to study these animals in a
5pa/■^^«« -mangrove community. Although
previous work (Gallagher and Reid, 1974) in-
dicated that the seawall is a less favorable
habitat than the Spart/na-mangrove area, obser-
vations indicated that the same pattern of
reci'uitment and zonation occurred in both places.
Therefore, we felt results of this study would ap-
ply generally to the species in this area.

The seawall is composed of upright concrete slabs
130-11(1 cm high and 120 cm wide; the canal bot-
tom is composed of soft mud and oyster bar. Dur-
ing the study the lowermost 30-40 cm of seawall
were encrusted with oysters (Crassostrea
riiyinicn) and barnacles (Biluitn.s lunphitrite.
('hfh<tni(du.s spp.). Tlie isopod, Ligid sp. was one
of the most conspicuous animals in the habitat.
An intertidal zone approximately 9 m wide ex-
tended horizontally from the base of the seawall
since this much of the canal bottom was exposed
at low spring tides. In 1971, at the beginning of
the study, both L. anguUfem and L. irromta
were present on the seawall, but during that year
the numbers of the latter species gradually
declined so that by 1972 none remained. 'Iliis

65-
60-

(/i

a

(/) 55H

w 50

\ 45-

._ '^0-
D
C 35-1

(f)

>. 3oH

W 25-

I ^°-
CZ 15-1

o
o

~B 5-1

Q.

O
Q_

I \

I
I

/

I
I

■♦ "OLD" YEAR CLASSES

O-

■^^^3 NEW RECRUITS

I I r

Sept Oct Nov Dec Jon
1971-72

I r

Sept Oct Nov Dec Aug Sept Oct Nov Dec July Aug Sept Oct Nov Dec

1972 1973 1974

FIG. 2. ConilMrisiin of imindnliiui density of new rn-nnts nml ulilcr i/ciir cldssiK of L. aiiKulifera in the iimntli^ m irhicli I Ik two
Uroiips (ire ciixiliidi.itiiiiiiii.ihnL

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 1(55

species continued to be abundant in local Spar-
tina marshes but did not return to the seawall.
Casual observation of other seawalls in the area
showed that while L. nngnlifcra was frequently
present, L. irrorata was rarely present, sug-
gesting that it was less able to adapt to that en-
vironment. Although these were the only two
supratidal mollusks on seawalls several inteitidal
mollusks inhabited the canal bottom.

Several species of algae grew upon the en-
crusted basal zone of the seawall. Tlie following
species of Cyanophyta (blue green) were found:
Anacystiii aeruginosa, A. montana. Por-
phip-iisiphon noiarisii Schizotkrix arenaria. S.
calcicola, Microcoleus lyngbyaceus, Entnphysalis
de^ista, and Mastigncoleus testanim. The last two
and Schlzothrir calcicola were found boring into
oyster and barnacle shells in the upper parts of
the encrusted zone. In addition to the blue green
algae, several species of red and green algae were
consistantly found on the lower 20 cm of seawall,
usually where it was protected by an overhang of
oyster growth and not subject to excessive desic-
cation. The following species of Rhodophyta (red
algae) were found: Polysiphonia suhtilissima,
Centroceras clavulatmn, and Ceramium
fastigiatum. Chlorophyta (green algae) included:
iUva sp.. Entcromorplia roiiipin^m. E. liitgnlittn.
Chaetomoi-iyha aerea. Qadophora delicatula, and
Qadophora sp. In addition numerous diatom
species were present. Both littorines fed in this
zone but actual species eaten were not deter-
mined.

Thus, while creation of seawalled canals has
apparently contributed to the decrease of species
diversity in Boca Ciega Bay (Taylor and Saloman,
1968; Sykes and Hall, 1970) some species are able
to adapt to the conditions, especially if an inter-
tidal zone is present. Since much of the shallow
water area of this bay formerly consiting of
grass flats, mangrove shores and Spartina marsh-
es has been converted to seawalled canals (Simon,
1974), we felt that studying snails in this type
of environment might add to knowledge of some
long-term effects of "dredge and fill" as well as
provide information of the life cycle of L. anguli-
fera.

METHODS

Pupulation fluctuations

Population changes were studied by means of
censuses of all L. angulifera in two areas of
seawall. Area A was a portion of seawall 13.2 m
long (eleven 120 cm slabs). Area B, 10.8 m long
(nine 120 cm slabs) was located approximately 25
m from Area A. All snails in these areas were
counted every 2-3 weeks from October 1971
through June 1972. and approximately each
month thei'eafter through May 1975, with addi-
tional censuses in May and July 1976. In some in-
stances slightly longer intervals elapsed between
counts. The seawall was 140 cm high in Area A
and the substrate at the base was soft mud: the
base of the wall was encrusted with oysters and
barnacles. In Area B the seawall was 130 cm high
and the substrate at the base was oyster bar; the
base was also encrusted with oysters and bar-
nacles, although the zone of encrustation was not
as wide as in Area A due to the contour of the
canal bottom. Total counts of L. angulifera were
converted to population densities expressed as
numbers of snails/m^ of seawall (Figure 1). From
September through December of each year new
recruits were recorded separately from previous
year classes since size differences between the
two groups were evident during censusing
(Figure 2).

Total shell height (from base of aperature to
tip of spire) of random samples (including all
snails on an area of exposed seawall at all levels)
of usually at least 100 snails was measured to 0.1
mm with vernier calipers to study the pattern of
size distribution and growth. Sizes of samples
taken after the 1974 red tide were small because
of the decrease in snail population then, but such
samples represent a large percentage of the re-
maining population. The samples were taken near
to but not in census areas and' usually were
retui-ned to the seawall after measurement to
avoid depleting the population and disturbing the
census areas. Size distribution curves (Figure 3)
are based on size classes of 1 mm intervals.
Figure 4 depicts the seasonal variation in mean
shell height for the population as a whole.
Growth of new recruits during 1972-73 was com-
pared with that of older snails (Figure 5) by
calculating mean shell height of new recruits and
older snails separately. During months when

166 THE NAUTILUS

October 30, 1979

Vol.94 (4)

c
o

3

Q.

O

CL

o

c

if)

19 Oct.. 1972

Size Class

FIG. 3. Seasonal variations in size class distribution o/L. angulifera /row October 1971 through May 1975.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 167

c
o

B

a.
o

Q_

o

c

Size Class

FIG. 3. (continued)

168 THE NAUTILUS

October 30. 1979

Vol. 91 (J)

E

e

0)

cn

c
o

C3t-7'I>£^Sr>t/iOZOc_-n2>Sc-^>wOZOc_-ri2>5<_c_

1971

1972

1973

1974

i S S ^ 2
1975

FK'i. 1. .SV ii.<iiii(il riiniilitiiix In niciiii sliill In iijlit n/'L. anpulifera.

sizes of the two groups overlapped a "cut-off'
point based on relative numbers of individuals in
different size classes was used. The same methods
of cen.-^usinp and shell height measurement were
continued during and after the high tide and red
tide episf)des. Particular attention was paid to
resultant changes.

In addition to the 1974 red tide there was a
less extensive outbreak in the summer of 1971.
Accurate census data were not obtained at this
time because snails in the census areas were
disturbed during other studies, but data available
indicate that there was a decline in population
density as a result of exposure to two "patches"
of red tide.

Zonation Patterns

Both the vertical migration and zonation level
of adult snails were investigated during the
spawning season from May to October. Addi-
tionally the developing zonation pattern of new
recruits was studied from November 1971
through May 1972. The position of snails on the
seawall was designated by dividing the seawall
into six zones from biise to cap. The lowermost
zone (zone 1) consisted of that part of the seawall
encrusted with oysters and barnacles and varied
from 30-40 cm deep depending upon the contour
of the canal bottom. The next higher zone (zone
2) included the area from the top of the encrusta-
tion to a dark stain on the seawall and w;us
uniformly 20 cm deep. The uppermost limit of
this zone was that of Mean High Water Spring
and the base of the seawall was at or just above

Mean Low Water. The remaining portion of the
seawall was arbitrarily divided into four addi-
tional zones (zones 3-6) each 20 cm deep. All
zonation study was done in Area A and snails
therein were not moved or disturbed.

To deteiTnine the zonation pattern of adult
snails, numbei-s of individuals in each of the six
zones in from 2-3 sections of seawall (about
75-100 animals) were counted and that number
converted to percent of all snails counted. Water
level, time of day, and general weather conditions
were recorded at each observation. If the tide was
sufficiently low to uncover the entire seawall the
water level was recorded as "0". Since snails were
not ordinarily found below the base of the
seawall, specific data on tides lower than this
were not obtained. Observations included the
hours from aiiproximately (1900 to 23iHi on 17
different days during both neap and spring tides
from 26 May to 2 October 1971, although not all
days included the veiT late observations. Observa-
tions were usually made four to five limes per
day, but as few as three and as many as eight
were made on .some days.

Since newly recruited snails were not seen
readily in the encrusted zone, the zonation pat-
tern of these .small snails was studied only when
zone I was under water and small snails visible
on bare seawall. In this case the relationship be-
tween the size of the snail and the di.stance above
the waterline was determined and zones only 10
cm wide were used. Figure 6 shows percentages
of snails at different levels above the water and
placement of snails as a function of size. Tlie two

Vol. 94 (4)

October 30. 1979

THE NAUTILUS 169

sets of data on zonation show different aspects of
the life cycle. One illustrates the adult pattern of
zonation and the other the development of that
pattern.

OBSERVATIONS AND RESULTS

Population Changes

a) General

Data in Figures 1 through 5 show that there
are seasonal changes in population density and
mean shell height reflecting the seasonal nature
of the L. angulifera reproductive cycle in this
area. The first new recruits settled on the seawall
sometime between late July and mid-August of
each year studied. Increases in population density
were evident by the end of August or early
September; there then followed a period of from
as few as 39 days to as many as 113 days when
the population density increased. Greatest
population density was reached during peak
recruitment in the fall of each year studied. Ac-
tual dates varied from late September in 1974 to
mid-November in 1973, but after these dates the
population declined steadily and reached a yearly
low in July or August just before recruitment
began again.

The smallest snails settling on the seawall
were 1..5 mm total shell height but most newly
settled individuals were in the 2.0-2.9 mm size

class and had five or six whorls. Attempts to find
presettlement snails in the environment failed, so
that the course of development from swimming
veliger with a maximum shell length of only 0.13
mm (Gallagher and Reid. 1974) to those capable
of settlement at 1.5 mm as found here is
unknovm. Length of time spent in the pelagic
stage can be estimated, however. In 1971, peak
spawning occurred during late August and early
September (Gallagher and Reid, 1974) and peak
recruitment occurred in early November (Figures
1 and 2). Thus about eight to ten weeks elapsed
between maximum spavraing and maximum
recruitment; this likely represents the length of
pelagic life for this snail.

Comparison of Figures 1 and 4 shows that
mean shell height of the population varies in-
versely with density. This is due in part, of
course, to the presence of large numbers of new
recruits during certain months, but in years of
greatest overall density snails tended to remain
smaller than in years of overall low density. A
weak positive correlation (r = 0.74) between densi-
ty and mean shell height of adult snails com-
pared and tested by the X^ method was found.

Size distribution curves (Figure 3) show
seasonal changes in recruitment and growth.
There is a distinct bimodal pattern in late sum-
mer and fall, although numbei-s of adults

20-

El6-
.E 14-
^ 12-

a>

a> 10-

X

-C 6-

(r>

c 4-
o

<U 2-

-cr--

.o"

<^o'

O— ^^O FIRST YEAR CLASS (NEW RECRUITS)
^— ^^« OTHER YEAR CLASSES

O'

Sept Oct Nov Dec Jon Feb Mor Apr May June July Aug Sept Oct

1972 1973

FIG. .5. Gymparisnn of the mean shell heights nf new recruits and idder iiear elasses of {,. angulifera in 1972-7-1 to show dif-
ferences in growth rate heticeen t he t wo i/roups.

170 THE NAUTILUS

October 30, 1979

Vol.94 (4)

representing previous year classes were much
smaller than those of new recruits. By the end of
December the two distinct sizes could not be
detected by gross observation but were still evi-
dent in size distribution curves. By March,
however, size distribution curves were no longer
distinctly bimodal, indicating that growth of new
recruits was greater than that of older year
classes and that they were "catching up" to them
in size. The total size range at this time was
large, ranging from 3.0 to 20.0 mm shell height
(except in 1974 following the red tide outbreak).
In summer, during spawning and just before
recruitment began, the size range was much
smaller, being from 9.0 to 18.0 mm in 1972 and
11.0 to 20.0 mm in 1973. Since snails can begin
spawning at approximately 10.0 mm shell height
(Gallagher and Reid, 1974). these data indicate
that most surviving recruits reached spawning
size toward the end of their fii-st year or at about
9-10 months post metamorphosis. Thus the size of
the total population in May, which is the start of
the spawning seasfjn in the Tampa Bay area, can
be regarded as the size of the breeding population
at the start of any given breeding season. Figure
5, which compares mean shell heights of new
recruits and older year classes from September
1972 through June 1973, shows the difference in
growth rates of the two groups of snails. New
recruits grew rapidly through the fall and winter
while older year classes grew little or not at all
during that period but increased in size from
March to May. Apparently grovrth is minimal
during spawning and winter months for adult
snails but is lapid for new recruits until they
reach adult size.

b) Miwtality

Although the data do not show seasonal
changes in mortality rate which may occur in
this snail, total yearly percent mortality can be
detennined by converting the decrease in popula-
tion density (from highest yearly density after
fall recraitment to lowest yearly density just
before recruitment) to percent of snails lost
(Table 1). This gives approximate ten month
"mortality rates" of 58 and 57 percent in 1971-72
and 1972-73 respectively, increasing to 94.5 per-
cent in 1973-74. the year of the extensive bloom
of (hjnitiixliiiinin breve If 57-58 jiercent is con-
sidered a normal ten month mortality (average

5.75 percent per month) expected yearly mortal-
ity can be extrapolated to be about 70 percent in
an average year. Older year classes continue to
decrease in density from September through
December (Figure 2) while new recruits show a
sharp increase in density for a period of six to
twelve weeks during recruitment. Therefore there
is a sharp decline followed by a more moderate
rate of decrease (Figure 2). Apparently many
new reci'uits do not survive even a few weeks in
the intertidal environment, and older year classes
decline in numbers throughout the year.

The percent increase in snails also varied in
different years (Table 2). Increase during recruit-
ment in Area A was 235 percent following losses
from the July 1971 red tide. Due to lack of sum-
mer census data for Area B, the percent increase
is not known. Figure 1 shows an exceptionally
heavy recruitment for both areas, especially Area
B. There is no explanation for this difference but
population densities in the two areas were
similar in all other years studied (Figure 1). Dur-
ing the next two years there was a 90 percent in-
crease in density (though actual numbers of snails
were different) possibly representing a normal
or average increase. Percent increase was excep-
tionally large (462 percent) following severe
population depletion after the 1974 red tide;
actual population size, however, was greatly re-
duced. The 1971 summer red tide, which con-
sisted of only two "patches" in the study area,
did not reduce the population to exceptionally
low densities (Table 2).

c) Effects of extremely high tides and a red
tide bloom

During the extremely high tides which ac-
companied Hurricane Agnes in June 1972, water
completely covered seawalls in the area, causing

TABLE 1. Percent decrease in snail population (Area A) from
highest yearly density at peak recndtment in fall of one year
to lowest yearly density before recruitment starts in the
folUnciny year.

1971-72 1972-73 1973-74

High Density*

77.0

.58.7

47.5

Low Density

32.3

25.0

2.6

Total Decrease

44.7

33.7

44.9

Pei'cent Decrease

.58.1

57.4

94.5

'Denisitv = number of individuals/m' seawall.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 171

TABLE 2. Percent increase in snail poptdation during
recruitment -Area A

1971

1972

1973

1974

Low Efensity'

23

32.3

25.0

2.6

High Density

77

61.6

47.5

147

Total Increase

54

29.3

22.5

12.1

Percent Increase

2a5%

90%

90%

462%

'Density = number of snails/m" seawall.

L. angulifera to crawl onto the cap of the
seawall. This left many individuals stranded on a
horizontal surface. Fifty stranded snails were
marked with waterproof paint to determine if
they would return to the vertical portion of the
seawall. After five days five of them had
returned, but subsequent observations showed no
more did so. There was a sharp drop in popula-
tion density from 59/m^ to 46/m^ in Area A
(Figure 1) immediately after the storm. The
decline was even greater in Area B which had ex-
ceptionally large numbers of snails from the
heavy fall 1971 recruitment. Resultant loss from
these high tides was 27 percent in Area A and 42
percent in Area B. As a consequence of greater
loss in Area B, population densities for the two
areas became similar and remained so during the
remainder of the study. These population losses
occurred suddenly over the course of a few days,
and there was no subsequent increase indicating
that stranded snails had returned to the seawall.
Thus, such stranding constitutes a lethal hazard
for this species in a seawall environment. It is
possible that in a mangrove habitat snails would
be able to move up and down greater distances
on mangrove trees and probably not be stranded.
In a Spartina marsh, snails would probably re-
main submerged near the tops of Spartina stalks
and if wave action or currents were strong be
washed off and lost. Most snails remained sub-
merged just under the cap of the seawall for
several hours during the hurricane. Lowest densi-
ty for that year was 32 snails/m^ (Figure 1) so ef-
fects of Hurricane Agnes did not reduce sharply
the actual numbers of spawning snails. No doubt
the extremely large numbers of snails as a result
of the heavy 1971 recruitment somewhat
ameliorated the damaging effects of Hurricane
Agnes on the population.

An outbreak of red tide caused by the
dinoflagellate Gymnodinium breve, occurred in
the study area from February through March,

1974. In the canal it appeared as patches of in-
fested water and was not present continuously. It
was most prevalent at high tides and tended to
concentrate in the upper 30 cm of water. Often
the accumulation was heaviest adjacent to the
seawall as if the wind was pushing the dino-
flagellates against the seawall which then acted
as a barrier to its dispersal, hence some very high
concentrations occurred here. The patch almost
always dispersed on the outgoing tide or if the
wind shifted. A new patch sometimes, but not
always, occurred with the next incoming tide.
Most patches extended between 5 and 10 m out
from the wall and lasted approximately six
hours. In the study area, most occurred from
mid-February through March, but the outbreak
in the Tampa Bay region lasted from January
through April. Following the appearance of red
tide in the canal, many L. angulifera were found
dead and dying in the mud at the base of the
seawall. Moribund animals seemed paralyzed and
unable to withdraw into shells or attach to
substrate. Many recovered when placed in non-
infested seawater in laboratory aquaria but no
controlled studies to determine effects of ex-
posure time and concentration were done.

There was a drastic reduction in the snail
population as a result of the red tide. The popula-
tion density on 24 January 1974 before any red
tide appeared in the canal was 27 and 31
snails/m^ in Areas A and B respectively. This is
comparable to densities in those areas on 19
January 1973 (36 and 32 snails/m^ Areas A and
B). On 25 February 1974 a few days after the
first appearance of red tide in the canal popula-
tion densities were only 8 and 9 in the two areas
(A and B). In 1973 density reduction after a com-
parable time was only by three snails in Area A
and none in Area B. There were further reduc-
tions in the population until low densities of 2.6
and 2.3 individuals/m' were reached in the sum-
mer of 1974 (Figure 1), representing a 94.5 per-
cent reduction from peak density in November to
yearly low in August (Table 1). Density of the
breeding population in May of that year was only
3 snails/m^ in the two areas studied. Presumably
similar changes occurred in other habitats in the
area so that the breeding population of L.
angulifera would be much reduced in the Tampa
Bay region for the 1974 spawning season.

172 THE NAUTILUS

October 30, 1979

Vol.94 (4)

Recruitment in 1974 began at the end of July and
reached a peak in late September, slightly earlier
than in previous years. The peak density reached
in the fall of 1974 following the red tide of the
previous winter-spring was 15 and 8 snails/m^ in
Areas A and B, far below peak densities reached
in other years (Figure 1) even though the percent
of increase was much greater than in previous
years (Figure 2). In May 1975 population den-
sities were 12 and 9 indicating that the L.
angulifera population was not back to pre-red
tide levels and still had a very reduced breeding
population. One year later in May 1976 popula-
tion densities were 15 and 13 snails/m^ in Areas
A and B, still below comparable dates for other
years. The last census taken (July 1976) showed
population densities of 12 and 5 snails/m^ in the
two areas counted. Apparently the effects of red
tide are long lasting for this snail for after two
years the population had not recovered in terms
of density.

A marked increase in mean shell height from
10.6 mm on 24 January to 13.8 mm (a total of 3.2
mm) on 25 February 1974 accompanied the initial
sharp decline in population density. On com-
parable dates in previous years shell heights in-
creased by 1.2 mm in 1973 and 0.4 mm in 1972. In
addition, on 24 January (before red tide) sizes
ranged from 4.0 mm to 20.0 mm (Figure 3). On 25
February (after red tide) sizes ranged from 9.0 to
18.0 mm. Since it is unlikely that snails in the 4.0
to 4.9 mm size class could grow to 9.0 mm in that
time, the data apparently indicate that mortality
was greater among the small snails; indeed, none
of the very small snails remained. Nearly all in-
dividuals still alive were of adult size. It is
probable, therefore, that the breeding population
in May 1974 was made up largely of animals two
or more years old. Thus, although few snails sur-
vive through two spawning seasons, those that do
would be important in species survival should an
event which kills new recruits differentially oc-
cur.

Zonation Patterns

a) Adult zonation and vertical movements
Adult L. angidifera were never found sub-
merged but always occurred above the water
line. During low tide periods, snails might mi-
grate down into the encrusted zone to feed, but

as they became wet with the rising tide, they
moved up and remained out of the water. In the
laboratory, animals placed in aquaria with small
amounts of water responded by crawling out of it
within 5-10 minutes. Lenderking (19.54) noted
similar behavior, and Hayes (1929), Evans (1965),
and Bingham (1972) demonstrated similar
responses in other species of Littorina. When
kept in aquaria for periods of two or more weeks,
however, L. angulifera migrated down to the
water level on occasion and fed from algae
covered rocks or shells. Records indicate no
periodicity to these migrations but tidal tanks
were not used. In this species, only spawTiing ap-
peared to have true tidal and lunar periodicities
(Lenderking, 1954; Gallagher and Reid, 1974).

Data obtained from observations on vertical
migrations of adult snails on the seawall show
that most L. angulifera were found in zones 3
and 4 or between 60 and 100 cm above the base of
the seawall in Area A. Measurements of the
water level at different tidal phases showed that
extreme high spring tides generally reach no
higher than 80 cm on the seawall, mean high
spring tide was at the top of the dark stain on
the seawall (zone 2), and mean low water just
below the base of the seawall in the study area.
Actual measurements on the seawall varied with
the contour of the canal bottom, resulting in nar-
rowing of the encrusted zone (zone 1), but the
pattern of zojiation in terms of tidal level is the
same, only the measurements are different. These
observations show that L. augulifera is a supra-
tidal snail occupying a zone corresponding to
the level of high spring tides and almost always
remaining out of the water. Since it is a species
of quiet water areas and wave splash is not a
factor, it is thus seldom subject to wetting
from spray as are some supratidal animals.

Movements into lower zones, presumably to
feed, took place only when those zones were ex-
posed but did not occur at every exposure. Data
presented in Table 3 show that at any given low
tide, whether neap or spring, usually less than 50
percent of the adult snail population migrated in-
to the encrasted zone, indicating such migrations
for adults are relatively infrequent. Dates of
heaviest migration occurred during more humid
periods when rain had occurred or when low
tides occurred in evening or early morning hours.

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 173

Apparently snails were more likely to move when
relative humidity was high. L. auyulifem did not
crawl in the mud at the base of the seawall even
during very low tides but always remained on
the upright seawall; thus, they never moved
lower than mean low water, and usually re-
mained well above this level. The same pattern of
zonation was also seen in Sixuiinn-nvdngnwe
areas, where snails were found only on stems and
prop stems of mangroves or Sixviina stalks, not
crawling on sand or mud at bases of these plants.

b) Zonation in new recruits

Newly recruited L. anguUfera remained close
to the waterline in a zone wetted by the minimal
wave wash in the canal. This zone was very nar-
row, usually not exceeding 10 cm. Snails nearly
always moved up and down so as to remain in
this wet zone, but they remained in the encrusted
zone during ver\' low tides and did not move out
over the mud at the base of the canal.

Smaller snails are closest to the waterline and
there is a progressive increase in size as distance
fi-om the water increases until the snails reach
adult size when they assume the adult position
and are likely to be found distributed throughout
the supratidal zone (Figure 6). There is nearly
always a small percentage of adult snails near
the waterline since snails go to the water (though
they do not submerge), probably to prevent ex-
cessive desiccation. During November, when
mean size is small due to large numbers of new
reciTiits, between 62.4 and 65 percent of all snails
were within 10 cm of the waterline, and between
17 and 25 percent were from 10-20 cm of it. By
December and January, the percent of snails
within 10 cm of the waterline had decreased to
between 22 and 30.5 percent. Sizes of such snails
remained small but there were fewer of them.
Data presented in Figure 6 show changes in zona-

TABLE 3. MUjratiiin into encmsted z<ine 2t)May tii 2 October 1972.

tion pattern of new recruits as they grow to
.spawiing size. With the exception of the unusual-
ly low zonation pattern seen for 14 March, there
is a general rise in zone level of this species as
the size of snails increases; adult size is reached
when animals are zoned at the level of high spr-
ing tides. This occurs in May at the start of the
spawiiing season when most new recruits have
reached adult size. These observations also
showed that during the fall and winter months,
mature snails from previous year classes re-
mained at the supratidal level; there was no
seasonal shift in zonation pattern of adults as has
been I'epoited for other intertidal snails (Frank.
1965; Palant and Fishelson, 1968). Only the new
recruits shifted from a waterline position where
they remained wet to a dr>' position as they grew
to adult size. Thus, the change in zonation pat-
tern seen as postlarval snails reach spawning size
can be considered a developmental phenomenon.

DISCUSSION AND CONCLUSIONS
The results presented here can best be sum-
marized in Figure 7 which illustrates yearly
changes in a population of L. anguUfera in the
Tampa Bay, Florida, area. In this area all the life
history stages are seasonal, therefore, it is easy
to delimit them. Spawning occurs during the
wanner months of the year (May to October). The
pelagic larvae also develop and begin to settle
during this time but peak recruitment is reached
in the fall 8 to 10 weeks after peak spawning.
Juveniles grow rapidly during cooler months of
fall, winter and early spring; at the same time
they attain the adult zonation pattern. Thus, dur-
ing growth to adult size there is a change from a
water-line position to a supratidal position. By
late May most of the young snails are ready to
spawn. Population changes and size distribution

Percent Snails moving
into Encrusted zone

Number of Days Seen

Percent of

in Encrusted zone

Total davs

19 days

4().ro

.5 davs

10.6%

IBdavs

40.-^

2 days

4.3%

2 days

4.3%

Less than ICf o

10 ■ 25%

2.5 -.50%

.50-75%
More than 75%

Total number of days observed — 47
The percent of snails seen in the encrusted zone during low tides on 47 different days of the 1972 spawning season. The days
include both neap and spring tides.

174 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

70

60
d 50

<.

2 40

S
5
H

I I"

O

I

_,10

_1

X

" 6
Z
< 4

o

70

9 NOVEMBER, 1971 go

50
40

30
20
10

0 20 !C 40 50 60 TO eo 90 lOO

IB
16
14
12
10
8

18 NOVEMBER. I97J

27 NOVEMBER, 1971

10 20 30 40 50 60 TO 80 90 iOO

10 20 30 40 50 60 TO 80 90 100

0 20 3C 4^1 50 fC 7C 80 90 lOO

70
60

=! 50

<I

I-
O 20

Z 18

Z 16

14

X

o

I

CO 6

DISTANCE ABOVE WATER LINE IN CM

70

12 DECEMBER. 1971

10 20 3C 40 50 60 TO 80 90 100

70
60
50
40
50
20
10

4 JANUARY. 1972

60-
50-

40-

SO-
SO-
10

>C 2C 30 40 50 60 70 80 90 lOO

10 20 30 40 50 60 TO 80 90 lOO

23 JANUARY, 1972

iC 20 JC 40 5C 60 TO 80 90 lOO

10 20 30 40 50 60 TO 80 90 lOO

10 20 30 40 50 60 TO 80 90 100

10 20 30 40 50 60 TO 80 90 100

DISTANCE ABOVE WATER LINE IN CM.

FIG. 6. Development of the zonation pattem in L. angulifera. The distance above the waterline as percent total snail population is
related to median shell height. (Median shell height is used here rather than mean shell height in order to eliminate bias in-
troduced by averaging the size of an adult snail which may be near the waterline— as mentioned such snails do occasionally
migrate to the waterline but would belong to the adult group mther than the new recntits whose zonation pattern this figure
depicts.)

Vol.94 (4)

October 30. 1979

THE NAITTILUS 175

70

60

12 FEBRUARY. 1972

<

z

50

CO

-I

40

<

H

30

o

*-

20

^^

s«

10

imi «!

lO 2C 10 40 50 e.C 70 80 90 lOO

5

18 ■

z

IS

t-

I

14

o

HI

12

^S jaBt/^E«

X

_]

10

-I

^^^^H^

HJ

e

^^^^^^^

X

^^^^^^^

to

6

^^^^s

z

^^^^^^^

<

^

^^^^^^

o

^^^^^^^

UJ

2

^^^^^^Bffi

5

^H^

14 MARCH. 1972

70
60-
50
40-
30
20
10

0 20 30 40 50 60 70 BO 90 lOO

3-6 APRIL, 1972

TO 80 90 lOU

10 20 30 40 50 60 70 80 90 ;C0 lO 20 30 40 50 60 70 80 90 lOO

DISTANCE ABOVE WATER LINE IN CM.

70-

« 60-

20 APRIL. 197

_l

< 50'

Z

<n

_i ""

<

1- 30

O

^ 20

ss

^M ■

10

gl liy

iO 20 10 4C 50 60 70 80 90 lOO

S 18 ■

s

2 16 ■

t- 14 ■

I

^ ,2

UJ

I 10

_l

-1 8

UJ

X

to 6

2

< 4

Q ,

UJ 2 ^

S

L

'0 20 30 4C 5C %0 70 80 90

00

70-
60
50
40
30
20
10

70-
16 MAY. 1972 50

50
40

30
20-

lO 20 30 40 5:J 60 ?0 80 90 lOO

M JUNE. 1972

(0 20 30 40 50 60 70 80 90 lOO

lO 20 3C' 4C 50 60 70 80 90 lOO

DISTANCE ABOVE WATER LINE IN CM.

176 THE NAUTILUS

October 30, 1979

Vol.94 (4)

patterns reflect these chanpes. The yearly cycle in
this area is much more sharply delineated than
in the Miami area where, as shown by Lender-
king (1954), spawning occurs throughout the year.
It follows, as she showed, that other life stages
are more or less continuous in that area also. No
doubt the greater seasonal variation in
temperature in the Tampa Bay area is, in part,
responsible for differences seen between the two
localities.

Data and observations indicate that L.
angidifera is a fast-maturing, probably short-
lived species much like LItfnrina lineatcu L.
linealatcu and L. ziczcw as reported by Borkowski
(1974). Most snails begin spawning about 9 to 10
months after metamorphosis. About 70 percent of
them d(j not reach a second spawTiing season,
much the same percent Borkowski (1974) found
for species of the Littorina ziczae complex.

Population changes in this snail are affected by
a variety of factors. These include unusual en-
vironmental events that do not occur regularly
ever>' year. During the course of this study two
such events, extremely high tides and a red tide
bloom, occurred. Because population changes in
groups of animals are susceptible to events of this
nature which vary from year to year, it is dif-
ficult to ascertain just what "average" or "nor-
mal" changes are. This could only be done by
observations over such a long period that effects
of unusual events would cancel out. Obviously a
three year study period is too short. In spite of
this, however, changes occurring in the unusual
years were compared with changes when no
unusual events occurred. In this way some indica-
tion of the magnitude of these environmental
stresses was obtained. The results show that
while these events caused drastic changes in- ac-
tual population numbers, the general changes ac-
companying the yearly life history remained the
same. Of the two, the red tide bloom was more
damaging than the extreme high tides. Not only
were the immediate effects of the red tide bloom
more severe but there were long term changes in
p<jpulation density as well. Further, since the red
tide differentially killed small snails, the com-
position of the spawning pt^pulation the following
year consisted primarily of older snails. Thus, the
older group, small in numbers compared to the
most recently spawTied group, had to make up the

deficit caused by the high mortality among new
recruits. As the data show, this caused a lasting
effect on population density.

Upon settling, very small snails remain close to
the waterline and move upward as they grow and
mature so that by the beginning of the spawning
season in May the adult zonation pattern has
developed. Other investigators have alsf) reported
an upshore size gradient of this type for inter-
tidal moUusks. Smith and Newell (1954)
demonstrated that this occurred with L. littorea
until the adult zonation pattern was reached at
about one year of age, after which individual
snails tended to remain at the level they had
reached at that time. They did not report any
vertical migrations of adults as noted here for L.
aiHiulifcm. and by Bingham (1972) for L. irmrata.
Palant and Fishelson (1968) found the same
phenomenon for L. punctata in that small in-
dividuals remained clustered in a wet zone near
the waterline, while large individuals were found
higher on the seawall. Chow (1975) reported an
upshore size gradient in L. .'icutnlata. with
smaller snails being found closer to the water.
Frank (1965), in a study of population changes in
the limpet Acmaea digitalL<!. found a similar size
gradient, with largest and oldest animals being
found higher in the intertidal zone. Vermeij
(1972), in an excellent review, reported such a
gradient for high intertidal to supratidal
mollusks during post larval stages but the op-
[josite gradient for those whose range was low to
mid-intertidal. Chow (1975) found that while
small snails were less resistant to desiccation
than large ones, all sizes were resistant to desic-
cation encountered in the envii-onment. Results of
preliminary, as yet unpublished, experiments
show that the same is true for L. augulifcra. The
zonation pattern of juvenile snails results in
favorable placement in respect to food and pro-
bably helps to ensure frequent feeding excui-sions.
TViis is likely necessary for snails to grow to
maturity by the spawning season in May. It may
\:>e more imiX)rtant in determining the zonation
pattern of juveniles than resistance to desicca-
tion. It is also possible, however, that placement
lower intertidally was an important factor in the
greater mortality of small snails during the red
tide outbreak. Larger snails remained higher on
the seawall and hence had a better chance to

Vol.94 (4)

October 30, 1979

THE NAUTILUS 177

SPAWNING SEASON

'Srowth of 1st Year Class to Spawning Size

Develop men ui mOuII Zonation Patiern

HIGHEST POPULATION
DENSITY PER YEAR

RECRUITMENT

JLOWEST POPULATION
DENSITY PE'r'yEAr|!

i *::■

Growth of 1st Year Class to Spawning Size

Development of Adult Zonation Pattern

OCT NOV DEC. JAN. FEB MARCH APR MAY JUNE JULY
FIG. 7. Diiifiniiii mitt ir ifjinsciiiatiiiii iiftlic i/fitrlti tiff

escape it. Smaller snails also may be more
susceptible to red tide toxins, but tests were not
made.

There is some evidence that snail growth may
be density dependent since during years when the
lowest density of the year is high, the greatest
mean shell height for that year is lower than in
years when the lowest density for the year is low
(Figures 1, 4). VeiTneij (1972) reported this for
the bivalve Tellina tenuis and Frank (1965) found
that growth of Acmaea digitalis was reduced dur-
ing crowding. Frank (1965) suggested that food
availability may be a factor, and such may also
be true here, although Bingham (1972) found that
it was not important in the distribution of L. ir-
rorata in a north Florida marsh since in that en-
vironment an excess of food was available in all
areas. The situation might be different on a flat
seawall which would present less surface area for
the growth of food organisms than would a marsh
or mangrove habitat. Gallagher and Reid (1974)
showed that L. angnlifera in a Spartina-ma.n-
grove area had a larger mean size than those on
a seawall, suggesting that food availability may
be a factor in a seawall environment.

Although this study illustrates and describes
the yearly life history of L. angulifera in the
Tampa Bay. Florida area much remains to be in-
vestigated regarding factors regulating these
events. Studies encompassing temperature

AUG SEPT OCT NOV DEC. JAN FEB MARCH APR MAY

histiiriiiifh. angulifera in the Tnnipii liii/. Ftundii. lu-rn.

tolerance, desiccation resistance, and identifica-
tion of food organisms are planned.

ACKNOWLEDGMENTS
We are deeply grateful to William G. Lyons,
Supervisor of Invertebrate Studies, Florida State
Department of Natural Resources, Marine Re-
search Laboratory, St. Petersburg, Florida, for his
critical reading of the manuscript. We also thank
Ms Karen A. Steidinger, Laboratory Supervisor,
for identification and measurement of the Gym-
riiidinium breve blooms, and Dr. Harold J.
Humm, Professor of Marine Science, University
of South Florida, St. Petersburg, for confirmation
of the algal identifications. We express great ap-
preciation to Mrs. Sally D. Kaicher for prepara-
tion of the figures and to Miss Stephanie
Schminke for the typing. Financial support has
been received from the Eckerd College Faculty
Development Fund.

LITERATURE CITED

Abbott. R. T. 1974. Amenran Seashells. 2nd Ed. Van Nostrand

Reinhold Co.. New York. 1974.
Bandel, K. 1974. Studies on Littorina from the Atlantic.

Veliger 17:92-115.
Bingham. F. 0. 1972. The influence of environmental stimuli

on the direction of movement of the supralittoral gastropod

Littorina irmrata. Bull. Mar. Sn. 22:.309-a35.
Bock. C. E. and R. E. .Johnson. 1967. The role of behavior in

determining the intertidal zonation of Littorina planaxis

Phillipi 1847 and Littorina scutulata Gould 1849. Veliger

10:42.54.

178 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

Borkowski, T. V. 1974. Growth, monality and productivity of
South Florida Littorinidae (Gastropoda: Prosobranchia)
Bull. Mar. Sci. 24:409437.

Broekhuysen, G. J. 1939. A preliminary investigation of the
importance of desiccation, temperature, and salinity as fac-
tors controlling the vertical distribution of certain inter-
tidal marine gastropods in False Bay, South Africa. Trans.
Royal Soc. (if South Africa 28:255-292.

Qiow, V. 1975. The importance of size in the intertidal dis-
tribution of Littorina scutulata. Veliger 18:69-78

Evans, F. 1965. The effect of light on zonation of the four
periwinkles, Littorim littorea (L.), L. obtv.sata (L.) L. sax-
alilis (Olivi) and Melarapha neritoides (L.) in an ex-
perimental tidal tank. Neth. Jour. Sea Res. 2:556-565.

Frank, P. 1965. The biodemography of an intertidal snail
population. Ex;ology 46:831-844

Gallagher, S B. and G. K. Reid, 1974. Reproductive behavior
and early development in Littorina scabra angulifera and
Littorina irrnrata (Gastropoda: Prosobranchia) in the Tam-
pa Bay region of Florida. Malacohjgical Review 7:105-125

Hayes, F. R. 1929. Contributions to the Study of Marine
Gastropods. Ill Development, Growth and Behavior of Lit-
torina. Contr. Can. Biol.. N.S. 4:413-430

Kensler, C. B 1967. Desiccation resistance of intertidal crevice
species as a factor in their zonation. Joum. Animal Ecol.
36:391406

Lenderking, R. E. 1954. Some recent observations on the

biology of Littorina angulifera Lam. of Biscajtie and

Virginia Kej-s, Florida. Bull. Mar Sci. Gulf & Carib.

3:273-'296
Merkel. R. D. 1971. Temperature relations in two species of

West American Littorines. Ecolog>- 52:1126-1130
Moore, H. B. 1937. The biology of Littorina littorea Part I.

Growth of the shell and tissues, spawning, length of life and

mortality. Jour Mar Biol. Assoc. UK 21:721-742
Palant. B. and L. Rshelson. 1968. Littorina punctata (Gmelin)

and Littorina neritoides (L) (Mollusca: Gastropoda) from

Israel: Ecology and annual cycle of the genital s>'stem.

Isreal Joum. Zool. 17:14.5-160
Rosewater, J. 1963. Problems in species analogues in world

Littorinidae. >lmer. MalacoL Union, Ann. Reps.. Bull 30:5-6
Simon, J. L. 1974. Tampa Bay estuarine system - a s>Tiopsis.

Flo. Sci. 37:217-244
Smith, J. E. and G. E. Newell. 1954. The dynamics of the

zonation of the common periwinkle Littorina littorea (L) on

a stony heach.Jaum. Animal Ecol 23:35-56
Sykes, .J. E. and J. R. Hall. 1970. Comparative distribution of

moUusks in dredged and undredged portions of an estuar>-.

with a systematic list of species. U.S. Fish and Wildlife

Service Fishery Bulletin 68:299-306
Taylor, J. H. and C. H. Saloman. 1968. Some effects of

hydraulic dredging and coastal development in Boca Ciega

Bay, Florida. U.S. Fish and Wildlife Sen^ Fish Bull.

67:213-241
Vermeij, G. J. 1972. Intraspecific shore-level size gradients in

intertidal mollusks. Ecology 53:693-700

SPHAERIIDAE AS INDICATORS OF TROPHIC LAKE STAGES

Arthur H. Qarke

Smithsonian Institution
Washington, D.C. 20560

ABSTRACT
Analysis of field data associated mth 35 species of boreal and arctic North
American Sphaeriidae indicates interesting correlations between species oc-
currences and types of lentic habitats. A few species combine the attnbutes of
stenotopy, broad geographical distribution, relative abundance and relative ease of
taxonomic identification and appear to be of use as trophic lake stage indicators.
These are: Pisidium conventus Qessin and Sphaerium nitidum Gessin for
oligotrophic lakes, P. idahoense Roper and S. striatinum (Lamarck) for
mesotrophic lakes, and P. rotundatum Prime and S. simile (Say) for eutrophic
lakes.

Tlie characterization of inland aquatic en-
vironments based on mollusks frequently con-
stitutes an integral part of Quaternary
paleoecological studies (Camp, 1974; Gibson, 1967;
Miller. 1966; Taylor, 1957; and Warner, 1968). In
such studies the whole biological assemblage pre-
sent (often consisting of pollen, ostracod shells,
mollusk shells, and fish bones) or the mollusk

assemblage alone (consisting of gastropod and
sphaeriid shells and possibly also of freshwater
mussel shells) may be analyzed and evaluated.
The use of only a few critical species of
Sphaeriidae for interpretation of paleoen-
vironments, or for characterization of existing
trophic lake stages, has not been attempted, at
least in North America.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 179

The Sphaeriidae (also known as Pisidiidae)
(Superfamily Corbiculacea) are a large worldwide
family of small freshwater, bivalved mollusks.
Unlike the other native families of freshwater
clams (Superfamily Unionacea) the shells are
small (15 mm or less in most species),
porcelaneous, and have lateral teeth both anterior
and posterior to the cardinal teeth. The life
histories of the North American species have
been described by Heard (1965, 1977).

A preliminary' summary of information con-
cerning the relative abundance, regional geo-
graphical distribution, and kinds of aquatic
habitats occupied by the sphaeriids of northern
North America is presented in Table 1. The
species list is believed to be complete for Canada.
With the exception of two warm -temperate
species in the southeastern United States (Eupera
cubensis (Prime) and Pisidium punctifeiitm (Gup-
py)) and one. rare, relict species in northern
California and southern Or^on (P. ultramon-
tanum Prime), the list is also believed to be com-
plete for the continental United States. Relative
abundance estimates, distribution approxima-
tions, and habitat identifications refer only to
populations in Canada and northern United
States. The abbreviations under Distribution
refer to ph>togeographic regions (see brief sum-
mary in Qarke, 1973).

Inspection of the table reveals that most
species are eur>topic, or wide-ranging in habitat
preferences. Among those which are common and
widely distributed, only a few are principally
associated with lakes in any one particular stage
of trophic development. These are, for
oligotrophic lakes: Pisidium conventus and
Sphaerium nitMum: for mesotrophic lakes: P.
idahoense and S. striatinum: and for eutrophic
lakes: P. rntimdatum and 5. simile. S. occidentale
(uncommon in Canada but locally common in the
United States) is characteristic of the most ad-
vanced aquatic stage in lake development, i.e.
swamps and temporary (vernal) ponds and pools.

-wilful UTih

t .«nlHul (oiih

iw™.

>-A

\

\ ^ fWnixucTbunl

\niT««.uiTU(Tjl

11

(~

FIG. 1. Parts of a sphaeriid shell (Pisidium idahoense Roper
left and right valves from different specimens), semidiagram-
maiic.

The following short descriptions and the il-
lustrations are designed to assist' limnologists
who are unfamiliar with the Sphaeriidae but who
wish to be able to identify the indicator species
here selected. The structural terms used are
defined in Figure 1 and the species are il-
lustrated in Fig. 2 and 3. The beaks (umbones)
are located dorsally and near the posterior end in
most species of Pisidium. In species of sphaeriids
which have the beaks more centrally located, the
anterior and posterior of empty shells can be
found by examination of the hinge teeth. The
right valve bears a single, very small cardinal
tooth located under the beak and 4 (2 pairs) of
narrow, elongate lateral teeth, one pair located
on either side of the cardinals. The left valve
bears 2 cardinals and 2 single laterals which ar-
ticulate with the corresponding teeth in the right
valve. In life the animal moves forward with the
beaks held upward, the right valve on the right
and the left valve on the left. The most elevated
part of each lateral tooth is the cusp. The posi-
tion is proximal if it is close to the cardinal teeth
(or tooth) and distal if it is far from them.

The user is cautioned that positive identifica-
tion of sphaeriid species is often difficult,

TABLE 1

(1)

Relative Abunda
Habitats of the Sph^

nee. Approximate Distributions, and Usual
Sphaeriidae of northern North America^^^

Abbreviations. Abundance: C, abundant or common; R, uncommon or rare; I, recently
introduced (relative abundance unstable). Distribution; A, arctic; T, arctic-boreal
transition zone; B, boreal forest; M, western montane region; P, prairie and parkland
region; G, Great Lakes-St. Lawrence forest region. Habitat: X, frequent occurrence;
X, infrequent occurrence.

180 THE NAUTILUS

October 30, 1979

Vol.94 (4)

SPECIES

a

CO

<

DISTRIBUTION

HABITAT

W of 95°

E of 95°

OLIGOTR.

MESOTR.

EUTROPH .

V-ERNAL

Plsidlum waldeni Kuiper

R

A T

X X X X

J

P. conventus Clessin

C

A T B M

A T B C

X X X X

XXXX

Sphaerlum nitidum Clessin

C

A T B M

A T B C

X X X X

XXXX

XXXX

P. compressum Prime

c

T B M P

T B C IX X X X

XXXX

XXXX

P. lilljeborgi Clessin

(■

A T B M P

A T B R

X X X X

XXXX

XXXX

P. nitidum Jenyns

{

A T R M P

T B C

X X X X

XXXX

XXXX

P. subtruncatum Malm

R

A T B M P

B C

XXXX IX XXX

XXXX

P. casertanum (Poll)

C

T B M P

T B C

X X X X

XXXX

XXXX

XXXX

P. idahoense Roper

c

A T B M

B r.

XXXX

XXXX

XXXX

P. fallax Sterki

R

B P

B R

XXXX

XXXX

XXXX

S. striatinum (Lamarck)

c

T B M P

T B G

XXXX

XXXX

S. comeum (I.)

1

R

XXXX

XXXX

P. amnicum (Mil Her)

I

G

XXXX

XXXX

P. ferrugineum Prime

c

A T B M P

A T B R

XXXX

XXXX

P. henslowanum (Sheppard)

I

R

XXXX

XXXX

P. supinum Schmidt

R

R

XXXX

XXXX

P. variabile Prime

c

T B M

T B G

XXXX

XXXX

P. ventricosum Prime

c

T B M

T B C

XXXX

XXXX

P. walkerl Sterki

R

A T B M

T B G

XXXX

XXXX

S, transversum (Say)

R

BMP

B G

X X X X

X X X X

-

P. adamsi Prime

R

B P

B G

XXXX

XXXX

P. mi 1 lum Held

R

IBM

T B C

XXXX

XXXX

S. lacustre (Muller)

c

T B M P

T B R

XXXX

XXXX

P. cruciatum Sterki

R

G

XXXX

P. dubium (Say)

R

C

XXXX

P. equilaterale Prime

R

B G

XXXX

P. punctatum Sterki

R

B M

B G

XXXX

P. rotuindatum Prime

C

IBM

T B G

XXXX

S. patella (Gould)

R

M

XXXX

S. rhomboideum (Say)

R

B M

T B G

XXXX

S. simile (Say)

C

B G

XXXX

S. partumelum (Say)

C

B P

B G

XXXX

XXXX

S. securis Prime

C

BMP

B G

XXXX

XXXX

S. occldentale Prime
P. Insigne Cabb
S. fabale Prime

R

M

T B R
G
G

/ 1

XXXX

\ _ _ _ _

XXXX

R
R

M

- - - llOLic only/ --------

i ^ .^ f 1 ^ nnlitl ^ .• ^ ^ -M — ^ ^

— — — Miotic oniy^ _ - — -

Vol.94 (4)

October 30, 1979

THE NAUTILUS 181

especially in Pisidium. Even though the eight in-
dicator species are among the easiest to identify,
for verification one should refer to Herrington
(1963), Burch (1972), Clarke (1973, 1979). or better
still, to all of these. 5. simile and 5. striatinutn
are the most abundant species of Sphaerium and
are the most frequently encountered, but in
Pisidium the most abundant is the variable
species P. casertanum (Poll) followed by P. com-
pressum Prime and several other species.

Sphaetium nitidum (Clessin) (Figs. 2, J-M) is
up to 6 mm long, rounded anteriorly, posteriorly,
and ventrally, and with centrally-located beaks.
Fine concentric striae (more than 12 per mm)
cover the shell and maintain their height and
spacing up over the beaks. There is no radial

ridge on the inside of the shell. The periostracum
is shiny and pale yellowish-brown.

Sphaerium occidentale Prime (Figs. 2, N-Q) is
up to 7 mm long, also rounded anteriorly,
posteriorly, and ventrally and with centrally-
located beaks. The fine concentric striae (more
than 12 per mm) which cover the shell are even
finer near and over the beaks. A low, flat, radial
ridge on the inside of the shell runs from the
beak cavity to the central ventral margin. The
periostracum is pale yellowish-brown to brown
and dull or somewhat glossy.

Sphaerium simile Say (Figs. 3, G-J), the largest
Sphaerium in North America, ordinarily exceeds
16 mm in length and may reach 25 mm. The shell
is long oval, rather thin to fairly thick, and

/*^^\

FIG. 2. Trophic lake-stage indicator species of Sphaeriidae. A-C, Pisidium rotundatum (USNM 595777, length 1.95 mm); D-H,
Pisidium ventricosum (USNM 16U25. 1.85 mm): J-M, Sphaerium nitidum (USNM 216222. S.i5 mm): N-Q, Sphaerium occidentale
(USNM iTiS.J2. 7.55 mm).

182 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

FIG. 3. TVnphic lake-stage indicator species of Sphaeriidae. A-C, Sphaerium striatinum (NMC 502S0. length 13.0 mm): D-F,
Pisidium idahoense (NMC 327J,8. 7.1 mm): G-J, Sphaerium simile (NMC 1,5082, 118 tnm): K-P, Pisidium conventus (USNM
363001. 3.0 mm).

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 183

covered with coarse concentric striae (8 or fewer
per mm near the center) which are more widely
spaced over the beaks. The periostracum is
brownish or yellowish, with concentric lighter
and darker bands, and the interior of the shell is
bluish.

Sphaerium stiiatinum (Lamarck) (Figs. 3, A-C)
is up to 14 mm in length, oval, and relatively
thick and strong. It is covered by concentric
striae (8 or less per mm) which are unevenly
spaced and irregularly strong or weak in the
same specimen, but are not weaker on the beaks.
It is also brownish or yellowish, with concentric
darker and lighter bands, and with a bluish in-
terior. In juveniles, the dorsal margin is curved
in 5. striatinum but straight in S. simile.

Pisidium conventus Clessin (Figs. 3, K-P) is
small (less than 3 mm long), variable in shape
(ordinarily some specimens are trapezoidal), thin,
fragile, suboval, not inflated, and with a dull
glossy periostracum. The hinge plate is long
(more than 3/4 the shell length), with cardinal
teeth overhanging the edge of the hinge plate,
and with lateral teeth thin and narrow and with
the cusps (the highest parts) located near the
outer ends. For further details see Heard, 1963.

Pisidium idahoense Roper (Figs. 3, D-F) is
large (for Pisidium), up to 12 mm long, but most
specimens are closer to 8 mm. The shell is ovate,
with a short dorsal margin, and with the surface
covered by fine, concentric striae (15 or more per
mm). These characters will distinguish P. ida-
hoense from the other large species of Pisidium
(P. adamsi, P. amnicum, and P. dubium). Al-
though P. idahoense is characteristic of meso-
trophic lakes throughout its range on the North
American mainland, it occurs in eutrophic lakes
on Prince Edward Island, Canada.

Pisidium rotundatum Prime (Figs. 2, A-C) (and
P. ventricosum Prime, Figs. 2, D-H) are both
small (about 3 mm long) and more spherical in
shape than most other Pisidium species. In P.
rotundatum the height divided by the length
(H/L) is .80 to .92 and the width divided by the
length (W/L) is .70 to .76. In P. ventncosum
(H/L) is .82 to 1.00 and (W/L) is .80 to .95. In P.
rotundatum. the beaks are located almost central-
ly or are posterior of center but in P. ven-
tncosum they are far posterior. In the left valve
of P. rotundatum the hinge plate between the

cardinal teeth and the anterior lateral tooth is
narrow and much longer than wide, whereas in
P. ventricosum it is thick and short, i.e. about
equally long and wide. P. rotundatum is
characteristic of eutrophic water bodies and P.
ventricosum occurs in both mesotrophic and
eutrophic lakes.

It is useful to remember that some small
marine bivalve mollusks resemble sphaeriids and
may be mistaken for them, and vice versa. This is
especially important in the interpretation of
fossil deposits. The various species of marine
bivalves all possess unique hinge teeth and other
differential characteristics, however, which can be
observed by careful examination. See Abbott
(1974) and included references for further in-
formation on marine mollusks.

It should be remembered that occasional
specimens of most sphaeriid species may be found
in all kinds of habitats. The presence of an in-
dicator species is therefore only significant as a
trophic lake-stage indicator if that species occurs
in relative abundance.

As one gains familiarity with Sphaeriidae, in-
terpretation of trophic lake stages based on them
becomes more practical. The shells of most species
are variable, however, and the significant
characteristics of the hinge teeth of Pisidium are
minute and difficult to observe. It is therefore
recommended that limnologists utilize for lake
classification a larger suite of indicator species
than that provided by the Sphaeriidae alone.

ACKNOWLEDGMENTS
I thank C. 0. Berg, G. L. Mackie, and J.
Rosewater for useful suggestions, Ms. Cathy
Lamb for laboratory assistance, and Mrs. Carolyn
Gast for preparing the drawings. The photographs
were supplied through the courtesy of the Na-
tional Museums of Canada and the Smithsonian
Institution.

REFERENCES

Abbott. R. T. 1974. American Seashells. Second Edition. Van
Nostrand Reinhold Company, New York. 663 pages.

Burch. J. B. 1972. Freshwater Sphaeriacean Clams
(Mollusca:Pelecypoda) of North America. Biota of
Freshwater Ecosystems Identification Manual No. 3. pp. i-
viii + 1-33. United States Government Printing Office,
Washington.

Camp, M. J. 1974. Pleistocene Mollusca of three southeastern
Michigan marl deposits. Sterkiana No. 56:21-64.

184 THE NAUTILUS

October 30. 1979

Vol.94 (4)

Clarke, A. H. 1973. The freshwater molluscs of the Canadian

Interior Basin. Malarologia 13:l-.509.
. (1980): The Freshwater Molluscs of Canada

Special Publications, National Museums of Canada, Ottawa

(in press).
Gibson, G. G. 1967. Pleistocene non-marine MoUusca of the

Richardson Lake deposit, Clarendon TowTiship, Pontiac

County, Quebec, Canada. Sterkiana, No. 25: 1-36.
Heard, W. H. 1963. The biolog>' of Pisidium (Neopisidium)

conventus Qessin (Pelecypoda:Sphaeriidae). Papers uf the

Michigan Academy of Science. Art^. and Letters i8:ll-S6.
. 1965. Comparative life histories of North

American pill clams (Sphaeriidae:ffeMf iwm). Malacologia

2(3):,381-m.

. 1977. Reproduction of fingernail clams (Sphaeri-

idae :Sp/iaenum and Mitsadium). Malacologia 16(2):42M55.

HerrinRtcm, H. B. 1962. A revision of the Sphaeriidae of
North America (Mollusca:Pelecypoda). Miscellaneaus
Publicatiiins, Museum of Zoology, University of Michigan,
118: 1-74, 7 plates.

Miller, Barry B. 1966. Five Illinoian molluscan faunas from
the -southern Great Plains. .Vfo/ofo/of/ia 4 (l)L173-260.

Taylor, D. W. 1957. Pliocene freshwater moUusks from Nava-
jo County. Arizona. Jimmal of Rdeontology 31(3):654-661.

Warner. D. J. 1968. Pleistocene Gastropoda of a lake deposit,
Rimouski County. Quebec, Canada. Sterkiana. No. 31:1-14.

URANIUM-SERIES AGES OF ECHINOIDS AND CORALS FROM THE UPPER
PLEISTOCENE MAGDALENA TERRACE, BAJA CALIFORNIA SUR, MEXICO

A. Omura W. K. Emerson T. L. Ku

Department of E^arth Sciences Department of Invertebrates Department of Geological Sciences

Kanazawa University American Museum of Natural History Universityof Southern California
Kanazawa 920, Japan New York, NY 10024 Los Angeles. CA 90007

ABSTRACT

Nine ""Th/^'^U and "^Pa/^^^U dates on six coexisting corals (Porites califor-
nica) and echinoids (Encope grandis) from the Magdalena Terrace, west coast of
Baja California Sur, Mexico, average 116,50O±6,0O0 years (± one standard devia-
tion). Based on this average, the newly named Magdalena Terrace may he cor-
relative with the Nestor Terrace in the San Diego, California area and possibly
with several other late Pleistocene terraces along the California coast thought to
have been formed during a highstand of the sea 120,000 - 125,000 years ago.
Although fossil echinoids contain uranium of secondary origin their ages are con-
cordant with those of the coexisting corals and suggest that the uranium uptake
occurred .^oon after the death of the organisms. 77!?.s. as well as the low "^Tli con-
tent in both the living and fossil Encope analyzed suggests that a further in-
vestigation of echinoids is warranted to examine their suitability .for
geochronological studies with U-series nwclides.

We report the ""Th/"''U and "■Pa/"'U dating
on two samples of the stony coral Porites califor-
nicn and four samples of the irregular echinoid
Encope grandis from marine terrace sediments at
Magdalena Bay (Bahia Magdalena) on the west
coast of Baja California Sur. Mexico. The mean
and standard deviation of the six "°Th/'^''U dates
are 117,000 ± 7,000 years. The mean and standard
deviation of the three "'Pa/"'U dates are
115,000 ± 5,000. The two methods are in con-

cordance, giving an average age for the nine
dates on the six samples as 116,500 ± 6,(X)fl years.
U-series dates exist for several terraces bordering
southern California (summary in Ku and Kern,
1974) and from Guadalupe Island (Isla Guada-
lupe), some 400 km off Baja California Norte
(Goldberg. 1965). Our dates are the first for
Pleistocene terrace sediments from penisular Baja
California. TVie radiometric dates now available
for the richly fossiliferous deposits of Magdalena

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 185

Ba.\' permit more precise regional comparisons of
this fauna with those of chronologically related
Pleistocene deposits dated previously.

The present results suggest that Pleistocene
specimens of echinoids, and possibly those of
other echinodeiTns, are potentially datable by the
U-series methods. This is significant in view of
the general scarcity of specimens of coral in ter-
race deposits. Echinoids, especially the disarticu-
lated plates and spines of regular ones (sea
urchins) and, to a lesser degree, the tests of ir-
regular ones (sand dollare) are not uncommonly
pi'eserved in terrace sediments. If reliable
radiometric dates can be obtained from echinoids,
the numerous terrace deposits of late Pleistocene
age along the West American borderland and
elsewhere throughout the world can be dated
more precisely.

1841, were collected from a Pleistocene terrace
about 1.5 km north of the village of Puerto
Magdalena (24°38'N, 112°09'W), on the east side
of Santa Magdalena peninsula, Baja California
Sur, Mexico, from The American Museum of
Natural History [A.M.N.H.] locality F-6
[ = California Academy of Sciences (C.A.S.) locali-
ty 754]; see Figure 1. The samples analyzed with
U.S.C. lab. nos. designated as AO-3, -4, -5 (Table
1) are from A.M.N.H. locality F-6 collected on
March 17, 1957 (Emerson, 1958). Those designated
as AO-6, -7, -8 (Table 1) are from C.A.S. locality
754, collected July 25. 1925 by G D. Hanna and E.
K. Jordan (Jordan, 1936).

The two Recent specimens (U.S.C. lab. no.
AO-1, -2) of Encope grandis are from San Carlos
Bay, near Guaymas, Sonora, Mexico (27°57'N,
lli°04'W).

SAMPLE LOCALITIES

The coexistent fossil specimens, comprising of
two samples of Pontes califomka Verrill, 1870
and four samples of Encope grandis L. Agassiz,

EXPERIMENTAL RESULTS
AND DISCUSSION
Table 1 summarizes analytical results of
samples AO-1 through AO-8. Known quantities of

Table 1. Radiometric and Age Data on Echinoids and Corals from Mexico

Lab
No.

Materia

1' Mineralogy

U
(ppm)

Th
(ppm)

"«Th
^^■'Th

""Th

"'Pa 5

Age (10=
""Th

-^^Pa^

AO-1

E.g.'

High-Mg
Calcite

0.204
±,003

<0.02

1.14
±.02

-

<0.01

<0.1

<1

<5

AO-2

E.g.=

High-Mg
Calcite

0.293
±.005

<0.02

1.14
±.02

-

<0.01

<0.1

<1

<5

AO-3

P.c-

Aragoni te

3.50
±.08

0.022
±.007

1.08
±.02

345
±108

0.656
±.025

0.892
±.045

116±8

110^"

-1 9

AO-4

E.g."

High-Mg
Calcite

0.465
±.008

0.035
±.003

1.01
±.02

28.1
±2.6

0.667
±.016

0.906
±.041

119±5

117*"

-IB

AO-5

E.g."

Low-Mg
Calcite

1.86

±.04

<0.02

1.05
±.02

>300

0.692
±.025

n.m.

128±9

n.m.

AO-6

P.c."

Aragonite

3.36
±.12

0.062
±.006

1.14
±.03

128
±39

0.663
±.036

n.m.

118±12

n.m.

AO-7

E.g."

Low-Mg
Calcite

1.56
±.04

0.070
±.010

1.06
±.02

46.2
±6.5

0.632
±.026

n.n.

108±8

n.m.

AO-8

E.g."

Low-Mg
Calcite

0.810
.010

<0.02

1.08
±.01

>400

0.647
±.020

0.910
±.043

113±6

-19

1

E.G.:

Encope grandis; P

.c: Por

-ites cal

ifornica.

Recent, dead-collected, beach specimen.
Recent, live-collected specimen.
Pleistocene specimens,
n.m. : not measured.

186 THE NAUTILUS

October 30,1979

Vol. 94 (4)

232 U_ 228'J^ ^j^(J 233p^ ^,g^p ^gg^J ^g y\^\^ traCCfS Ih

the analyses of the radioisotopes listed. The
quoted errors (one standard deviation) are based
on the counting statistical fluctuations only.
Mineralogical identifications were done with
x-ray diffraction techniques. In computing
the ages, we assumed that "°Th and "'Pa were
initially absent or present in negligible amounts
and that samples acted as a closed system after
incorporation of the radioisotopes. The half-life
values used for ""Th and "'Pa are 75,200 years
and 34,300 years, respectively.

The assumption of negligible initial ""Th and
"'Pa (Table 1) is suppf)rted by the observations
that, firstly, "'•Th/"'Th values in the fossil
specimens are very much higher than those
values in natural waters or sediments, which are
commonly 1 to 3, and secondly, modern specimens
of E. yrandis show very low ^^°Th/"''U and
"'Pa/"*U values of <0.1, as is the case for corals
(Ku, 1968). The closed-system assumption is sup-
ported by the concordancy checks between the
"°Th/"^U- and "'Pa/"'U-" derived ages on three
samples in which such checks were made (Table
1). The validity of this assumption is alscj
reflected in the agreement, within counting
statistical error, of ages for the six coexisting
fossil specimens.

As the present study reports the first mea-
surements on echinoids, a discussion of the data
obtained is in order. The ""U/"' U ratios of 1.14
in AO-1 and AO-2 are the same as that for
uranium in sea water (Ku, et ai, 1977). Living E.
'(innidis apparently incorporate about 0.2-0.3 ppm
of uranium directly from sea water. Unlike coral,
there appears to be a discrimination factor of 10
to 1 in favor of Ca to U in the uptake of these
two elements from sea water by the organism.
With the exception of the echinoderm teeth, the
hard tissue of echinoderms is known to be
originally composed of calcite containing several
per cent Mg (Chave, 1954; Schroeder et al., 1969).
This is the case for samples AO-1, -2, and -4.
Because high-Mg calcite is metastable under sur-
face conditions, its transformation to low-Mg
calcite could provide conditions condusive to ex-
change of radionuclides with thase in the
surroundings— conditions similar to the conver-
sion from aragonite to calcite for coral. Data on
samples AO-5, -7. and -8 suggest that during the

transformation to low-Mg calcite, significant
amounts of uranium may have entered the
echinoid skeletal tests with little or no accompa-
nying thorium isotopes. For sample AO-4, the
slightly higher-than-modem U value (ppm) fur-
ther suggests that limited addition of uranium
could have also occurred before the transforma-
tion. This secondary uranium added to the sam-
ple is largely of non-marine origin, judging from
the "''U/"«U value of 1.01 ± .02 (oceanic uranium
would decay from 1.14 to 1.10 in about 120,tKX)
years).

From the above discussion, one sees some
parallel between E. gy-andis and mollusks in
terms of open system for secondary uranium up-
take in fossil specimens. However, the present
results show two encouraging aspects of dating E.
grandvi: (1) The concordant ages obtained here
suggest that the open-system episode must have
been brief and limited to a period very close to
the death of the organism. (2) There is evidence
for n^ligible presence of initial and extraneous
"°Th and "'Pa in the samples analyzed (Table 1).
These favorable conditions have been found in
mollusks, but they are not common (Kaufman, et
al., 1971). Thus for echinoids, one needs to deter-
mine how commonly these conditions occur and
what criteria are required to distinguish them.
These questions cannot be answered from the pre-
sent limited number of analyses. Further studies
of echinoid tests to evaluate their suitability for
U-series dating are warranted.

MAGDALENA TERRACE-OCCURRENCE,

FAUNAL ASSEMBLAGE

AND CORRELATION

The terrace represented by A.M.N. R locality
F-6 (Fig. 1) extends along the shore at a max-
imum elevation of approximately 6 meters above
sea level. The fossils are most numerous in
sediments of poorly sorted sand and angular ig-
neous rocks exposed along the shore at the high
tide level to an elevation of 1.5 to 1.8 meters. The
fossiliferous sand is locally overlain by 0 to 4.6
meters of non-fossiliferous alluvial cover. A con-
glomerate resting on the terrace platform, which
cuts into the basal igneous bench-rock, is exposed
at the level of the present beach on the apparent-
ly correlative terrace remnants that are pre-
served along the shore for about 1.5 km south of

Vol. 94 (4)

October 30, 1979

THE NAUTILUS 187

AREA OF .

IHOtX MAP \^ N

FIG. 1. Iiidei- map afthe Magdalena Bay - Almejiui Bay area ofBnja California Sur. Mexico, showing Pleistocene fossil localities (F-5,
F-6 on Santa Magdalcna peninifula: F-7. F-S on Santa Margarita Island) described in the text.

Puerto Magdalena village (Figure 1, A.M.N.H.
locality F-5 = C.A.S. locality 982). This con-
glomerate and the terrace platform are not ex-
posed at locality F-6. According to Hanna (1925),
these terrace remnants represent the beach-line
existing at the time of uplift of the igneous and
metamorphic rocks which form the higher terrain
behind the village, and this tectonic event re-
sulted in the closure of the northern entrance
to Magdalena Bay. A terrace similar to that at
Puerto Magdalena is exposed north and south of
the village of Puerto Cortes on the eastern shore
of adjacent Santa Margarita Island (Isla Santa
Margarita), which faces Almejas Bay (Bahia
Almejas), see Figure 1. This terrace extends
about 6.5 km along the shore south of Puerto
Cortes at a maximum elevation of about 4.6 m (at
A.M.N.H. locality F-7) and continues north of the
village at the same height for about 1.2 km
(Figure 1, A.M.N.H. locality F-8=C.A.& locality
932). The terraces exposed at the localities on
Santa Margarita Island are cut into basal igneous

rocks (0-1.5 m in thickness) and are overlain by
conglomerates (.5 to 6 m), fossiliferous sand peb-
bles (.5 to 1.2 m), and pebbly soil cover (.5 and 1.2
m). The terrace appears to be tilted slightly to
the northwest, as is the terrace on the Santa
Magdalena peninsula. These topographic features
are here designated the Magdalena Terrace, with
the type locality restricted to the section exposed
at A.M.N.H. locality F-6 on the Santa Magdalena
peninsula.

The presence of well-preserved metazoan in-
vertebrate fossils, mostly mollusks, in terrace
sediments in the vicinity of Magdalena Bay has
long been known. Hinds (1844) was the first to
report mollusks "... embedded in the fossiliferous
cliffs which surround a portion of the Bay of
Magdalena." Dall (1918), Smith (1919), Jordan
(1924), and Hanna (1925) considered the age of
these terraces to be Pleistocene, based on faunal
evidence. Jordan (1936) listed a total of 442
species-group taxa, including 4 echinoderms, 1
coral, and 337 mollusks, from three locations in

188 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

Magdalena Bay (C.A.S. localities 754, 932, and
982). He concluded that "...the beds should be cor-
related with the warm Upper San Pedro, or Up-
per Quaternary" (of Arnold (1903) in the Los
Angeles Basin, now referable to the upper
Pleistocene Palos Verdes Sand). The Magdalena
Bay assemblage is the largest Pleistocene in-
vertebrate fauna described from Pacific Baja
California (Emerson, 1956; Gastil et ai., 1975)
and, in western North America, it is second in
size only to the assemblages reported from
Newport Bay, California, where nearly 500
species of metazoan invertebrates are recorded
from late Pleistocene deposits (Kanakoff and
Emerson, 1959).

The fauna! constituents of the Magdalena Ter-
race are essentially modem in composition, con-
taining a nearly equal mixture of Panamic and
Califomian Provincial faunal elements, together
with wide-ranging, eurytopic taxa. The metazoan
invertebrates living at the present time in
Magdalena Bay also represent a blending of these
faunal components, with perhaps a diminution in
the ratio of the warm water (Panamic element)
to the temperate water components (Califomian
element). The Panamic element is present in
similar terrace deposits occurring northward
along the continental borderland. This southern,
warm-water element diminishes in numbers
rapidly in Pleistocene assemblages north of Viz-
caino Peninsula (27°50'N., 115°5'W) and is a
minor faunal component in the San Diego and Los
Angeles embayments, where wide-ranging and
cooler faunal elements dominate (Emerson, 1956).
Changes in the composition of these assemblages
have been largely ascribed to alternating
hydroclimatic regimes that accompanied the late
Pleistocene oscillations of the continental ice
sheets (cf. Valentine, 1955, 1961; Kanakoff and
Emerson, 1959; Addicott and Emerson, 1959;
Kennedy et al.. 1979). Because species-level ex-
tinctions in faunas have been negligible during
the late Pleistocene and tectonic changes in the
coastal configuration have locally obscured the ef-
fects of eustatic changes in sea level during this
period, traditional stratigraphic and paleontologic
methods do not permit absolute temporal and
regional correlations of these terraces (cf.
Durham and Allison, 1960; Ku and Kern, 1974).
The U-series ages obtained here suggest correla-

tion of the Magdalena Terrace with the Nestor
Terrace in San Diego and similar terraces in the
region, formed during a highstrand of the sea ap-
proximately 120,000 yrs. ago (Ku and Kem, 1974)
during the early Sangamon (isotopic stage 5e of
Shackleton and Opdyke, 1973). More precise cor-
relation must await absolute dating of additional
regional deposits.

ACKNOWLEDGMENTS
Peter U. Rodda, Chairman of the Department
of Geology, California Academy of Sciences,
generously contributed fossils for dating (C.A.S.
locality number 754). William E. Old, Jr. of the
Department of Invertebrates, American Museum
of Natural History kindly provided technical
assistance in the preparation of the manuscript.
We are indebted to George L. Kennedy, U. S.
Geological Survey, Menlo Park, California and
Leslie F. Marcus, City University of New York,
for critically reading the manuscript. The
radiochemical analyses were done at the Univer-
sity of Southern California supported by National
Science Foundation grant EAR 77-13680 to T. L.
Ku and W. H. Easton, Contribution no. 394,
Department of Geological Sciences, University of
Southern California.

LITERATURE CITED
Addicott. W. 0. and W. K. Emerson. 1959. Late Pleistocene

invertebrates from Punta Cabras. Baja California. Mexico.

Amer. Mus. Novitates. no. 192.5. 33 p.
Arnold, R. 1903. The paleontolog>' and stratigraphy of the

marine Pliocene and Pleistocene of San Pedro, California.

Calif Acad. Sci. Mem. 3:1-419.
("have, K. E. 19.54. Aspects of the biogeochemistry of

magnesium: 1. Calcareous marine organisms. Jour. Geol. 62:

587-599.
Dall, W. H. 1918. Pleistocene fossils of Magdalena Bay, Lower

California, collected by Charles Russell Orcutt. Tfte

Afa?rfi7i(.s 32:23-26.
Durhiun, .1. W. and E. C. Alli-son. 1960. The geologic history of

liija California and its marine faunas. Systematic Zool.

9:47-91.
Emerson. W. K. 19.56. Pleistocene invertebrates from Punta

China, Baja California. Me.xico, with remarks on the com-
position of the Pacific Coast Quaternary faun;is: .■\mer.

Mus. Bull. 1I1:31.5-:M2.
1958. Results of the Puritan - American Museum

of Natural History Expedition to western Mexico. 1.

General account. Amer. Mus. Novitates no. 1894, 25 p.
Gastil, R. G., R. P. Phillips, and E. C. Allison. 197.5. Recon-
naissance geology of the State of Baja California. Geol. Soc.

Amer. Mem. 140, 170 p.

Vol.94 (1)

October:?!), 1979

THE NAUTILUS 189

Goldberg, E. D. 1965. An observation on marine sedimentation
rates during the Pleistocene. Limnol. and Oceanog. Suppl..
10:R 125-128.

Hanna, G D. 1925. Ebcpedition to Guadalupe Island. Mexim. in
1922. Prnc. Calif. Acad. Sci., ser. 4. 14:217-275.

Hinds, R. B. 1844. (On new species of Terebra). Proc. Zool. Soc.
London, pt. 11, "for 1843": 149-168.

Jordan, E. K. 1924. Quaternary and Recent molluscan faunas
of the west coast of Lower California. Southern Calif. Acad.
Sci. Bull. 23:145-156.

1936. The Pleistocene fauna of Magdalena Bay,

Lower California. Contr. Dept. Geol. Stanford Univ. 1:103
-173.

Kanakoff, G. P. and W. K. Emerson. 19.59. Late Pleistocene in-
vertebrates of the Newport Bay area, California. Los
.Angeles Co. Mus. Contrib. Sci., no. 31: 47 p.

Kaufman, A., W. S. Broecker, T. L. Ku. and D. L. Thurber.
1971. The status of U-series methods of mollusk dating.
Geochim. Cosmochim. Acta 35:1155-11&3.

Kennedy, G. L.. K. R. Lajoie, and J. F. Wehmiller. 1979. Late
Pleistocene and Holocene zoogeography. Pacific northwest
coast. Abstracts, Cordillian Section, Abstracts with Pro-
grams, Geol. Soc. Amer. 11(3):87.

Ku, T. L. 1968. Pa."' method of dating corals from Barbados

Island. Jour. Geophys. Research 73:2271-2276.
Ku, T. L. and J. P. Kern 1974. Uranium-series age of the up-
per Pleistocene Nestor Terrace, San Diego, California. Geol.

Soc. Amer. Bull 85: 1713-1716.
Ku, T. L, K. G. Knauss and G. G. Mathieu. 1977. Uranium in

open ocean: Concentration and isotopic concentration.

Deep-Sea Res. 24: 1005-1017.
Schroeder, J. H.. E. K. Dwornik and J. J. Papike. 1969.

Primary proto-dolomite in echinoid skeletons. Geol. Soc.

Amer. Bull. 80:1613-1616.
Shackleton, N. J. and N. D. Opdyke. 1973. Oxygen isotope and

palaeomagnetic stratigraphy of equatorial Pacific core

V28-238: Oxygen isotope temperatures and ice volume on a

W and W year scale. Quat. Res. 3:39-55.
Smith, J. P. 1919. Climatic relations of the Tertiary and

Quaternary faunas of the California region: Proc. Calif.

Acad. Sci., ser. 4, 9: 123-17.3.
Valentine, J. W. 19.55. Upwelling and thermally anomalous

Pacific Coast Pleistocene molluscan faunas. Amer. Jour. Sci.

253: 462-474.
. 1961. Paleoecologic molluscan geography of the

Californian Pleistocene. Univ. Calif. Publ. Geol. Sci. 34:

1309-442.

THE NAIAD FAUNA OF LAKE SPRINGFIELD, ILLINOIS:
AN ASSESSMENT AFTER TWO DECADES

Walter E. Klippel and Paul W. Parmalee

Department of Anthropology'
University of Tennessee, Knoxville, Tennessee 37916

ABSTRACT

A sui-vey of the naiad fauna uf Lake Springfield during 195S pniduccd nine
species of freshwater mussels. A second survey of the identical collection localities,
conducted in 1977. produced the same nine species. Patterned quantative changes
in the fauna were observed. Qualitative changes have resulted from the introduc-
tion of four previously unrecorded species. Variations in the naiad populations
have been discussed in terms of observed changes in other aiiificinlly formed lentic
habitats as well as unimpounded fluvial systems.

Nearly two decades after the construction of
Lake Springfield during 1935, a survey of the
lake's naiad fauna was, conducted and reported
by the junior author (Parmalee 1955). The lake,
situated in Sangamon County in central Illinois,
is fed by Lick and Sugar creeks, has a surface
area of 17.6 km^ and roughly 90 km of shoreline.
At the time of the 1953 survey central Illinois
had suffered several months of below average

rainfall and by October, 1953, the level of Lake
Springfield fell to an average (169.07 m MSL) 1.62
m below normal pool (170.69 m).

The_exposed shoreline of the relatively shallow
lake (X depth = 4.57 m) gave rise to the survey
of stranded freshwater mussels along the waters
edge. Nine hundred and eighty-seven specimens
representing nine species were recovered from 20
different collecting stations (Fig. 1). The area

190 THE NAUTILUS

October 30. 1979

Vol.94 (4)

FIG. 1. Lake Springfield, Rlinois, shoviing stations where
tuiiads were collected in 195.i and 1977.

sampled (4x50 yr.) at each loci was about 167.4 m,
(200 yr^), bringing the total area collected to 3346
m^ and providing a mean density of .295/m^

Quadnda quadnda (Rafinesque, 1820) occurred
in greatest abundance (48%), followed by Lep-
todea laevissima (Lea, 1830)— 22%, Lasmigona
complanata (Barnes, 1823)— 11%, Ligumia riasutn
(Say, 1817)-11%, Anodmta grandis (Say, 1829) -
6%, Amblema plicata (Say, 1817)-1%, and
Anodmta imbecilis (Say, 1829)— 1%. Fusconaia
flava undata (Barnes, 1823)— 1% and Arddens
confragosnLR (Say, 1829)— 1% were represented by
only one specimen each (Parmalee 1955:32).

During 1976, slightly over two decades after
the low water of 1953, central Illinois was once
again subjected to below average rainfall which,
by early winter, had left Lake Springfield 1.56 m
(169.13 m MSL) below normal pool. The water
level continued to drop until February, 1977,
when it finally reached a low of 168.80 m MSL.

By March, 1977, the snow cover that had
blanketed the otherwise exposed shoreline had
melted, and during the next ten days a second
survey of the 20 loci collected during 1953 was
completed. During this period the lake level
ranged from 169.13 m MSL to 168.95 m MSL (Fig.
2a) and was an average 169.19 m MSL; a mean
level only 12 cm higher than the mean level for

October, 1953, when the initial sun^ey was con-
ducted. By May, 1977, the lake had again at-
tained a normal pool (Fig. 2b).

Distances of 50 m were marked off along the
waters edge at 18 of the 20 stations and collec-
tions of all shells with one dimension larger than
1.5 om were made for a distance of 4 m back
from the waters edge. In two instances (Stations 9
and 23) the areas collected were extended to 100
m long by only 2 m wide because of heavy grass
and brush cover that occurred within 3 to 4 m of
the waters edge. Both of these stations are at the
headwaters of the lake where the water line
begins to take on characteristics more like the
btinks of Sugar and Lick creeks than the shore-
line of Lake Springfield. Although the dimensions
(100x2 m) differ from areas established at the
other 18 stations (50x4 m), even,' attempt was
made to collect the same amount of surface area
at all stations, i.e. 200 m^. It should be noted at
this point that the areas collected during 1977
(200 m^) are roughly 20 percent larger than the
areas collected in 1953 (200 yr^ = 167.3 m^.

A total of 2177 paired valves were recovered
from the 20 stations during 1977. The area
sampled at each station was 200 m^ bringing the
total area collected to 4000 m^ and providing a
mean density of .544/m^ or almost twice as many
specimens per unit area as found at the same loci
during 1953.

Qualitative Changes in the Naiad Fauna

Qualitative changes have occurred in the lake's
fauna as a result of the introduction of four new
species (Carunndina paira (Barnes, 1823), Tmn-
rilla truncata Rafinesque 1820, Obliqrmria reflexa
Rafinesque 1820 and Corbinda manilcns-is Philip-
pi). There has also been an overall increase in the
lake's naiad fauna of roughly ten percent per
unit area as well as statistically significant quan-
tative changes among the nine original species.
Unfortunately the myriad of unmonitored, inter-
related factors responsible for the observed
changes cannot be fully delineated post de facto.
but there are some patterned variations that can
be discussed.

The nine original species (1953) constitute 1296
of the total 2177 specimens recovered in 1977.
When these primary species are considered sep-
arately (n = 1296), the naiad density per unit area

Vol.94 (4)

October 30, 1979

THE NAUTILUS 191

is only slightly greater (.324/m^) than that found
during the first survey (.295/m^). Increases in the
mussel fauna are restricted to as few as seven
stations (i.e. 2, 5, 6, 9. 10, 12, and 15) situated
along the main body of the lake (Fig. 1) where in-
creases per unit area by station range from 71
percent to 204 percent. Density was nearly the
same per unit area at station 16 (i.e. < 2 percent
change) while densities per unit area at the re-
maining 12 stations decreased rather markedly.

The upper reaches of the lake and the heads of
many of the inlets have undergone considerable
aggradation through siltation. This phenomenon
was readily apparent when collections were made
in 1977. The substrate at stations 4 and 13
(inlets), 17, 18, 19 and 20 (upper reaches of lake)
consisted of poorly consolidated silty clay loams
and were difficult to collect without sinking
waist deep in "muck". Also, the color of these ag-
grading deposits was noticeably darker (Table

TABLE 1. Frexhwatfr ninsscl.': nrorcrrd front tiirntij statians alutui the expiised shiireUiic of Lake Springfield. Iltindia. diiriiiy
1953 and 1977.

O I.

— a>

1 2 '3

■-J tj 'op

.3,2 2, 2:i

?S 1^ I'S

11 §2 i-f

Of O- ^ a ^ -rf

.3 § .3.2

t

a a, «

■ri ■a u

fc « -J •.»

■-■3 ,0 a.

!l 5

1

ne,ne,se,se of Sec.
12; T15N; R5W (SE)*

lOYR 5/4

1953
1977

17
8

4

18
15

4

57

18
76

2

nw.se, sw,ne of Sec.
19; T15N; R4U (NC)

lOrR 4/4

1953
1977

105

1

3
3

5

115

2 18

15

5
150

3

nw,nw,se,se of Sec.
14; T15N; R5U (NC)

lOVR 4/4

1953
1977

1

26
25

13

2

11
3

15

7

25

85
57

2

18

16

85
93

i

nw,ne,nw,sw of Sec.
24; T15N; R5W (NC)

lOYR 3/2

1953
1977

1

26

17

11

2
1

8

18
13

17

81
45

3

18

27

81
93

5

se,ne,nw,ne of Sec.
25; TISN; R5W (NC)

lOrR 4/2

1953
1977

28
26

24

1

5

1

12
24

33

52

109

3

59

26

52

197

6

se.se, sw,sw of Sec.
19; T15N; R4W (NC)

lOYR 5/4

1953
1977

4
18

2

3

5

11

16
37

6 11

223

16
277

7

se,sw,sw,se of Sec.
19; T15N; R4W (NC)

lOYR 4/4

1953
1977

78
22

3

6
6

96
32

2 3

70

96

107

3

sw,nw,nw,sw of Sec.
30; TISN; R4W (NC)

lOYR 5/4

1953
1977

2

25
23

10

10

3

54
30

3 23

48

54
104

9

sw,nw,se,se of Sec.
36; nSN; R5H (NC)

lOYR 3/1

1953
1977

20
65

I

3

8
5

36

74

17

5

36
96

10

ne,nw,sw,se of Sec.
35; T15N; R5W (NC)

lOTR 3/3

1953
1977

12

174

17

1
4

16

29
48

68

249

4

24

75

68
353

U

se,se,nw,sw of Sec.
36; T15N; R5U (NC)

lOYR 3/3

1953
1977

1

33
16

5

3

45
21

7

3

45
31

12

ne,sw,se,se of Sec.
35; TISN; R5U (NC)

lOYR 3/3

1953
1977

2

26

203

3

5

21
14

60
231

1

26

10

60
268

13

sw,se.se,ne of Sec.

2; T14N; R5U (NC)

lOYR 3/1

1953
1977

21
2

1

3

2
3

34
10

I

4

34

15

14

ne,ne,sw,nw of Sec.
2; TUN; R5H (C)

lOYR 4/3

1953
1977

16
33

1

12

1

13

5

4

49
41

11

1

49
53

15

sw,rTW,ne,nw of Sec.
16; T14N; R5W (C)

lOTR 3/3

1953
1977

6

75

1
1

6
2

7
10

10

30
96

1

7

1

30
105

16

sw,nw,nw,sw of Sec.
3; T14N; R5U (C)

lOYR 3/2

1953
1977

2

25
44

1

9

3

13
8

52

61

6

12

52

79

17

nw.sw.se.nw of Sec.
32; T15N; R5U (C)

lOYR 3/1

1953
1977

14
10

11

1

3

13
9

31
31

1

5

31
37

18

ni5,ne,sw.sw of Sec.
30; T15N; R5W (C)

lOYR 3/1

1953
1977

30

2

5
2

1

39
4

39
4

19

nw,nw,nw,sw of Sec.
9; T14N; R5W (C)

lOYR 3/1

1953
1977

54

7

12
12

13

21
6

100
25

100
25

20

sw,5w,se,sw of Sec.
34; T15N; R5W (C)

lOYR 3/2

1953
1977

17

1

4

4

9
3

5

36
12

2

36

14

•Determined from 7.5 minute UbGS quadrangles: (SE) ■ Springfield East; (NC) - New City; (C) - Chatham.

192 THE NAUTILUS

October 30, 1979

Vol.94 (4)

1-lOYR 3/1, 3/2) than substrates at most other
stations where yellowish brown and brown soils
(primarily Hickory, Clinton, and Elco series— as
depicted on advance soil sheets for Sangamon
County) are eroding from the former valley walls
of Sugar Creek (Table 1). Aggrading deposits
transported into the lake from the nearly black
upland prairie soils are very dark gray (lOYR
3/1— Munsell) to very dark grayish brown (lOYR
3/2) and consistently produced fewer naiads per
unit area (X.ll/m^) than were found during 1953
(X.32/m^). The relatively undiluted herbicides
and/or pesticides, and large quantities of smoth-
ering silt particles that settle out when they
reach the sluggish waters of the lake have prob-
ably contributed to this decrease in primary
naiad density at these stations.

Quantative changes among the primary species
have also taken place over the past two decades.
A chi square conducted on the 1953 and 1977
populations (Table 2) clearly shows that there
have been significant quantative changes in the
naiad fauna (X^ = 202, df = 8. p .< .001). Q.
quadrula, A. grandis and A. imbecUis occurred in
greater frequencies than expected during 1977
while L. cotnplanaUi, L. laevissima, A. plicata,
and L. nasuta have decreased. Variation in oc-
currence of L. complanata, Q. quadrula. L.
/aem,s('»(a, A. plicata and L. natiuta contribute
the greatest respective amounts to the high chi
square value.

A comparison of the combined assemblages

TABLE 2. Ncdad fauna recorded for Lake Springfield during
195J compared to the same specien recovered in 1977.

total naiad
fauna (1953)

partla
fauna

1 naiad
(1977)

naiad epecles

fo

fe

fo

fe

total

Anblenu plicata

14

6.5

1

8.5

15

F^i.tninnm tlni'it midiitu

1

0.9

I

1.1

2

Quadrula quadrula

472

581.9

874

764.1

1346

Anodonta grtmdie

63

80.4

124

106.1

187

Anodanta vnbecilie

7

U.7

20

15.3

27

Arcidana oonfragoBUB

1

0.9

I

1.1

2

Latmigoruz acmplanata

HI

53.6

13

70.4

124

Leptodsa latvieeina

213

168.6

177

221.4

390

ligumia naeuta

105

82.2

85

107.9

190

Total

987

1296

2283

from the heads of inlets and upper reaches of the
lake (i.e. stations 4, 13, 17, 18, 19 and 20) for the
1953 and 1977 populations has been made by con-
structing a contingency table similar to that in
Table 2. At these loci A. grandis. A. imbecilis and
L. laevissima occurred in greater frequencies
than expected during 1977 while Q. quadnda. L.
aiinplanata, L. nasuta and .4. plicata occurred in
fewer numbers than expected. Even when the "no
zero cell' requirement is fulfilled and .4. plicata
and L. complanata are excluded (including only
Q. quadrula, A. grandis. A. imbecilis. L.
laevis.Kim(i, and L. nasuta). a chi square shows a
statistically significant difference between 1953
and 1977 population (X^ = 33, df = 4, p < .001).

All three of the species that occurred in
greater frequencies than expected are known to
be more tolerant of mud substrates and lentic
waters than many of the species that occur in the
lake (Parmalee 1967:47, 48. 74). This observation
tends to substantiate our previous supposition
that naiad populations at these loci are being in-
fluenced by siltation, as does the fact that Q.
quadrula recovered from these areas are all
mature individuals generally over five years of
age.

By way of comparison we have combined the
assemblages at the seven stations on the main
body of the lake that showed an increase mussel
density per unit area (i.e. Stations 2, 5, 6, 9, 10,
12, and 15) between 1953 and 1977. A contingency
table shows that Q. quadrula. A. grandis and .4.
imbecilis occur in greater numbers than expected
while the other six primar>' species occur in a
lower frequency than expected. A chi square on
eight of the nine species (excluding A. plicata
since none was found during 1977) shows the two
I»pulations to be significantly different (X^ =
235 df = 7: p < .001). These species are the same
three that occurred in greater frequencies than
exj^ected when all 20 stations were combined and
1953/1977 samples were compared. A similar ma-
nipulation of mussel counts from remaining sta-
tions, i.e. those with decreased naiad density but
not on the upper reaches of the lake or at heads
of inlets, show changes in the same direction that
other stations on the main body of the lake dis-
play.

Despite the lower naiad densities at these sta-
tions, Q. quadrula, A. grandis and A. imbecilis

Vol.94 (4)

October 30, 1979

THE NAUTILUS 193

FIG. 2. Lake Springfield. Illitmx at Station 13 shoiring ex-
posed svbstmte near the head of an inlet during March 1977.
Water level is at 169 in MSL

occur in greater frequencies than expected while
the remaining species occur in fewer numbers
than would be expected if the populations had
undergone no change over the past two decades.

Qualitative Changes in the Naiad Fauna

Four species of freshwater mussels recovered
during 1977 were not found in the lake during
the 1953 survey. Of the four species established
since 1953, C. manilensis was found in greatest
frequency. It made up 28 percent of the total
specimens recovered during the 1977 survey and
was second in abundance only to Q. quadrula.
Had all specimens of the Asiatic clam been col-
lected, they would have been quantitatively the
most significant naiad in Lake Springfield. Lit-
erally thousands of C. manilensis were not col-
lected because they were less than 15 mm in
diameter. In fact, the lower limit of 15 mm was

established after the first station was visited as
the task of collecting all Corbicula was found to
be nearly impossible given the amount of time
available for the second survey.

Corbicula manilensis was introduced into the
fluvial systems of North America as late as 1938
and has since spread to most major drainages in
the United States (Sinclair 1971). The environ-
mental conditions this freshwater clam is able to
tolerate in Illinois are varied but as late as the
mid 1960s it was not found in the Mississippi
drainage above Carlo in Illinois (Parmalee
1967:95). However, over the past ten years the
species has become established in the Illinois
River (Thompson and Sparks 1977:34) and the
major reservoirs of the Sangamon River drainage
(e.g. Lake Springfield, Lake Decatur, Sangchris
Lake) in central Illinois. In some drainages this
species has been found to exceed 269,000/M^ in
density and in instances has become so numerous

FIG. 3. Lake Springfield, Illinois, at Station IS (inlet) during
May. 19 77. Water level is at normal pool (1 70. 69 m MSL).

194 THE NAUTILUS

October 30, 1979

Vol. 94 (4)

as to pose problems at power generating and
water filteration installations (Sinclair 1971).

Three species of naiads (i.e. 0. reflexa. C. par-
va, and T. tntncataj endemic to the Mississippi
River drainage have also become established in
Lake Springfield since the initial survey. All
three species were known to exist in the Sanga-
mon River drainage at the time of the 1953
survey. 0. reflexa and T. (nnicata were reported
common in the South Fork of the Sangamon not
far from the lake, and an abundant population of
T. tnmcata and C. jxirm was noted observed in
Lake Decatur (Parmalee 1955:31) just upstream
from Lake Springfield in the Sangamon River. It
was speculated at the time of the 1953 survey
that these species were either not present in
Sugar Creek prior to its impoundment or that
they were primarily lotic species that were not
able to adapt to the man-made lentic habitat
formed by Lake Springfield.

Results of our 1977 survey clearly demonstrate
that these three, especially 0. reflexa. are capable
of maintaining viable populations in a man-made
reservoir like Lake Springfield. The fact that over
3300 M^ was systematically collected at 20 dif-
ferent loci and that considerably more shoreline
was sporadically surveyed (but not collected) and
none of these naiads were found during 1953
argues strongly for a more recent establishment
of the species. Live specimens of 0. reflexa.
utilized in another study (Parmalee and Klippel
1974), were collected at Station 9 in August 1971;
several individuals were between five and six
years of age, which indicates this species had
become established in the lake at least by 1965—
and probably earlier. In contrast, C. manilenms
was not present at this same station as late as
spring 1973.

The means by which these mussels could have
been introduced are numerous, but two of the
most likely avenues known to us are: 1) their in-
troduction as glochidia with fish (primarily, but
not exclusively, white bass) obtained from other
fluvial systems in Illinois and placed in Lake
Springfield by the Illinois Department of Conser-
vation during 1951 and 1974, or 2) through the
emergency water supply system that was estab-
li.shed by City Water, Light, and Power shortly
after the low water of 1953. This system consists
of a canal that was excavated from a dividing

dam along the east shore of the lake to nearby
Horse Creek. Water from Horse Creek flows in
the canal to the dividing dam from where it is
pumped into the lake. According to City Water,
Light, and Power records, the pumping facility
was operated for a short period after its comple-
tion in 1956 and again during 1976 and 1977
when as many as 900 million gallons per month
were pumped from the canal into Lake Spring-
field. Either small fish infested with glochidia
and/or glochidia suspended in the water may
have been carried through this pumping facility.

Regardless of how these three species were in-
troduced they all seem to have become well
established and are fairly widely distributed. ().
reflexa was the third most numerous species
recovered during the 1977 survey. It was only
outranked in frequency by Q. qitadnda and C
manilensw and was nearly as ubiquitous as the
first and second ranked species (Table 1). 0.
reflexa is noticeably absent and/or in low fre-
quencies along the upper reaches of the lake and
at the heads of inlets (e.g. Stations 13, 17, 18, 19,
and 20). In general, 0. reflexa occurred in
greatest frequencies at those same stations where
the primary species were found in increased den-
sity per unit area during 1977 (e.g. Stations 2, 5,
9, 10, and 12).

C. parva and T. tntncata were the eighth and
ninth respective most numerous of the 13 species
recovered. C. parva was found at and near rallec-
tion stations throughout the lake while T. trun-
cata in sampling strata were exclusively
restricted to the east shore of the main body of
the lake (e.g. Stations 2, 6, 7, and 8). At least 20
additional T. truncata were observed outside the
sampling loci at these stations but in only one in-
stance was the species observed along any other
portion of the lake. This location was approx-
imately 90 meters outside the area collected at
Station 5 which is also along the lower portion of
the main body of Lake Springfield but on the
west shore. Whether the present low population
number is a result of what appears to be a fairly
recent introduction (the largest individuals are
ca. 4-5 years of age) or the inability of a typical
river species to adapt to a lake environment is
not clearly understood.

Vol.94 (4)

October 30, 1979

THE NAUTILUS 195

Comparisons and Discussion

Few thorough studies of quantitative and
qualitative changes in naiad fauna resulting from
artificial impoundment of fluvial systems and
subsequent adaptation to lentic environment have
been reported for North America. The pelecypod
fauna from Lake Texoma in Texas and Oklahoma
have been studied and reported (Riggs and Webb
1965; White and White 1977) and some work had
been conducted in the Red River prior to its im-
poundment (Isely 1925). Conclusions set forth on
the basis of the most recent studied suggests that
"despite the many conditions seemingly working
against the pelecypods of Lake Texoma, it can be
said with some degree of confidence that they are
flourishing when compared to their original di-
versity and abundance" (White and White 1977:
251).

Unfortunately quantitative data are not avail-
able to measure the strength of this observation.
Variations in survey strategies preclude the pos-
sibility of making direct comparisons from one
report to the next. White and White (1977:248)
note, for example, that "Tlie .study by Riggs and
Webb (1956) found that the mussel populations
of the lake were much more established than had
been indicated previously; however, since they
surveyed only one of the possible lake habitats, a
loamy-sand substrate, the data could not be used
to draw conclusions about the abundance of spe-
cies throughout the entire lake." In fact Riggs
and Webb (1956:200) report information that in-
dicate the average naiad density was .39/m^ dur-
ing 1953 while information provided for more
varied habitats by White and White (1977:242)
show that the mean density was .12/m^ during
1975-1976. Only two of the stations collected by
White and White (1977-stations 7 and 9) pro-
duced as high a density (> .24/m^) as the station
producing the lowest density during 1953 (Station
8) when a portion of the lake was collected by
Riggs and Webb (1956). The 1975-1976 collections
did produce three species not collected by Riggs
and Webb (1956), i.e. L. complanata, 0. refleoca
and LampsiiLs teres. However, the significance of
this observation is also rendered less impressive
when one considers that White and White (1977)
collected a surface area of over seven times as
great as the area collected during 1953.

Unlike the claims made for Lake Texoma, most
observations made on naiads in the impound-
ments of the larger, previously swift, streams and
rivers of southeastern United States indicate that
mussel populations have been drastically altered
(e.g. Bates 1966; Stansbery 1964; Isom 1969).
Bates (1966:235) notes, for example, that "Most of
the large river forms which were characteristic of
the pre-impoundment assemblage [in the Ten-
nessee River] are now typically absent from these
shallow water habitats" in the Kentucky Reser-
voir. "The one exception noted here is Q.
quadnda, which has successfully invaded these
areas. Many juveniles of this species were col-
lected from both the beach areas and the mud
shallows indicating a much higher biotic poten-
tial for this species than for the other Union-
inae." In addition to Q. quadrida and C. parva,
various species of Leptodea and Anodonta com-
prised the dominant naiads recovered by Bates
(1966).

Pronounced changes in mussel population of
unimpounded fluvial systems have also been well
documented. In many of the streams of the Mid-
west the overriding observation is that popula-
tions have undergone various degrees of degradia-
tion (e.g. Clark 1976; Matteson and Dexter 1966;
Starrett 1971). One point of interest here is that
all three of these reports on mussels in streams
flowing through or bordering Illinois note the
hardiness of Quadrida qimdnda despite siltation
and pollution (Clark 1976:8; Matteson and Dexter
1966:99; Starrett 1971:363). Also of interest is
Clark's (1976:8) notation of recent increases in the
occurrence of 0. reflexa in the Wabash River.

A survey of pre-impoundment Lick and Sugar
creeks in central Illinois was never undertaken.
Consequently it is impossible to compare or con-
trast species of the original lotic environment
with those in the subsequent artificially produced
lentic environment resulting from the construc-
tion of Lake Springfield. However, mussel popula-
tions of the lake were surveyed (1953) nearly two
decades after impoundment (1935). Slightly over
two decades later (1977) a survey of the same loci
collected during 1953 was again undertaken. Re-
sults of this second survey conclusively demon-
strate that naiad density per unit area has gen-
erally increased and that species diversity has

196 THE NAUTILUS

October 30, 1979

Vol.94 (4)

also taken place in Lake Springfield. In this
respect the results of this second survey are
similar to the claim for Lake Texoma, i.e. "in-
creasing density and diversity within the lake"
(White and White 1977:235).

Seven of the ten species reported for Lake Tex-
oma occur in Lake Springfield and seven of the
12 species recovered from Lake Springfield are
also found in Lake Texoma. Riggs and Webb
(1956:201) report L. laevissirym and Q. qmidnda
as the first and second respective most common
species in Lake Te.xoma while White and White
(1977:242) report L. laeinssima and A. yrandis as
the two most numerous species. In the Lake
Springfield populations for both 1953 and 1977, Q.
quadrula was most numerous and L. laenssima
the second most common of the Unionacea. Also,
as in the case of Lake Springfield, 0. reflexa is a
recent addition to Lake Te.xoma as it was not
recovered by Riggs and Webb (1956) in 1953.

While Q. fjuadritla has seemingly decreased in
Lake Te.xoma, the species has actually increased
in frequency in Lake Springfield. This seems to
conform to some findings in both streams and
rivers of the Midwest (Matteson and De.xter 1966)
and lake environments in the South (Bates 1962).
The manner in which Lake Springfield does not
appear to compare favorably with many other
reported populations in the Midwest and South-
east is that there does not seem to be an overall
degradation of naiad populations. Degradation of
the population seems to be occurring in the upper
reaches of Lake Springfield, as well as at the
heads of inlets, but populations in the main body
of the lake generally have thrived over the past
two decades. However, as Lake Springfield con-
tinues to silt in, it is expected that the naiad den-
sity per unit area will continue to decrease and
that A. (jrandis, A. imbecilis, and L. laevmima
will continue to increase in relation to other
species in the agrading portions of the lake.

Hinge Anomalies

Anomalies occurring in the form of transposed
lateral hinge teeth have been noted in freshwater
bivalves for over a centur\' (Agassiz 18.59: I^ea
1860). Van der Schalie (1936) revised Lea's 1860
list and included his own records of species ex-
hibiting various combinations of transposed teeth

which he accumulated during many years of in-
tensive collecting. In addition to the eight species
recorded by Lea, van der Schalie listed 18 others
which represented (for all species) 72 anomalous
individuals. None of the hinge variations de-
scribed by these workers were found in species
belonging to the genus Qiiadiida, so the oc-
currence of transposed teeth in 13 individuals
from the 1977 sample of Q. quadnda collected in
Lake Springfield is worthy of note.

The normal dentition in species belonging to
the family Unionidae consists of double lateral
and pseudocardinal teeth in the left valve and a
single lateral and pseudocardinal tooth in the
right. At least five distinct variations were
observed among the 13 anomalous individuals:
single lateral in each valve (N = 3): double
lateral in both valves (N=3): single lateral in
left, double in right (N = 4): double lateral in left
valve, partly treble in right (N = 2); treble
laterals in both valves (N = l). One of the in-
dividuals possessing a single lateral in the left
valve and double lateral in the right is addi-
tionally noteworthy because the i3seudocardinal
teeth are also transposed. Whether or not re-
versed or transposed hinge teeth in freshwater
bivalves are a result of environmental or genetic
factors is not clearly understood. However, the
fact that such variations in hinge structure do oc-
cur, even if uncommonly to rarely, is significant
in relation to their use as characters in iden-
tification and classification. Transposed hinge
teeth were not noted in individuals of the other
species from Lake Springfield. The anomalous
specimens of Q. quadnda comprised approximate-
ly one percent of the sample of that species.

Summary

Systematic surveys of the naiad fauna in the
artificially formed lentic environment of bike
Springfield of central Illinois were undertaken
during 1953 and 1977. Comparable survey strat-
egies employed during both sun'eys has made it
possible to make direct comparisons of the naiad
populations over a period of a quarter of a cen-
tury.

Both quantitative and qualitative changes have
occurred in the naiad fauna. Generally, the naiad
density per unit area h;is increased along the

Vol.94 (4)

October 30, 1979

THE NAUTILUS 197

shores of the main bt)dy of the lake while the
density in the upper reaches of the lake and at
the heads of the inlets has decreased. Com-
mencerate with the decreased density that has oc-
curred in these portions of the lake that have
been agrading over the past 25 years are the
changes in relative proportions of certain species
of mussels; L. laevissima. A. grandis. and .4. ///;-
bcciliti have increased with respect to other species
in these habitats.

Qualitative changes in the mussel fauna have
also taken place in Lake Springfield. All of the
species recovered during 1953 were also recorded
during 1977. In addition, four species (i.e. C. par-
va. T. truncata. 0. reflexa. and C. manilensw)
have become newly established in the lake. Depo-
sition of silt in the areas of entry of the feeder
creeks appears to greatly inhibit the establish-
ment and growth of naiads. With continued
heavy silting at several locales in the lake, ac-
cidental introduction or periodic stocking of fish,
and with possible unforeseen changes in the pre-
sent lake habitat, a future study of the mussels of
Lake Springfield may well provide additional
useful data relative to population dynamics
under artificial conditions.

ACKNOWLEDGMENTS

We would like to thank Arthur E. Bogan,
Department of Anthropology, University of Ten-
nessee, Knoxville, for his assistance with the in-
itial sorting and processing of the Lake Spring-
field naiads. James R. Purdue, Illinois State
Museum, Springfield, furnished the photograph in
figure 2b and Marl in Roos, Illinois State
Museum, Springfield, provided prints of all of the
figures.

LITERATURE CITED

Agassiz. Louis. 1859. Notes on Unio ligamentimts reversed.

P)vc. Boston Sue. Nat. Hisl. 7:166-167.
Bates. John M. 1962. The impact of impoundment on the

masse! fauna of Kentucky reservoir. Tennessee River.

Amrr Midi Nat. m:2»>--m.
Clark, Clarence F. 1976. The freshwater naiads of the lower

Wabash River. Mt. Carmel. Illinois to the south. Sterkiana

61:1-14.
Isely. F. B. 1925. The fresh-water mussel fauna of eastern

Oklahoma. Proc. Okla. Acad. Sri. 4:43-118.
Isom, B. G. 1969. The mussel resource of the Tennessee River.

Malacoloyia 7:397-425.
Lea. Isaac. 1860. Proceedings of Acad. Nat. Sri,. Phil. 51-.53.
Matteson. Max R. and Ralph W. Dexter. 1966. Changes in

Pelecypod populations in Salt Fork of Big Vermilion River,

Illinois 1918-1962. The Nautilus 79:96-101.
Parmalee. Paul W. 19.55. .Some ecological aspects of the naiad

fauna of Lake Springfield, Illinois. The Nautibi.^ 69:28-.34.
. 1967. The fresh -water mussels of Illinois. III. St.

Mj«. Pop. Sri. Sw. 8:1-108.
and Walter E. Klippel. 1974. Freshwater mussels

as a prehistoric food resource. .4mer. Antiq. 39:421-434.
Riggs. C. D. and G. R. Webb. 19.56. The mussel population of

an area of loamy-sand bottom of Lake Texoma. ,4 me?-. Midi.

AVir. 56:197-203.
Sinclair, R. M. 1971. Annotated bibliography on the exotic

bivalve dirbicula in North America, 1900-1971. Sterkiana

43:11-18.
Stansbery, D. H. 1964. The Mussel (Muscle) Shoals of the Ten-
nessee River revisited. Ann. Report Amer. Malacol. Union.

1964:25-28.
Starret, William C. 1971. A survey of the mussels (Unionacea)

of the Illinois River: a polluted stream. HI. Nat. Ifist, Surv.

Bull. 30:266-403.
Thompson, Carl M. and Richard E. Sparks. 1977. The Asiatic

Clam, Corbiculo manilenfds in the Illinois River. The

Nautilus 91:31-36.
van der Schalie, Henrv-. 1936. Transposed hinge teeth of North

American naiades. The Nautilus 49:79-84.
White. David S. and Susan J. White. 1977. Obser\-ations on

the pelecvTxid fauna of Lake Texoma, Texas and Oklahoma,

after more than 30 years impoundment. Southwest. Nat.

22:2a5-254.

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