ZOOLOGICA

SCIENTIFIC CONTRIBUTIONS OF THE
NEW YORK ZOOLOGICAL SOCIETY

VOLUME 54 • ISSUE 2 • SUMMER, 1969

PUBLISHED BY THE SOCIETY
The ZOOLOGICAL PARK, New York

Contents

PAGE

4. Some Mexican and Central American Land Snails of the Family Cyclo-

phoridae. By Fred G. Thompson. Plates I- VII; Text-figures 1-14 35

5. The Underwater Song of Erignathus (Bearded Seal). By Carleton Ray,
William A. Watkins, and John J. Burns. Plates I-III; Text-figure 1;
Phonograph Disk 79

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Published November 17, 1969

© 1969 New York Zoological Society. All rights reserved.

4

Some Mexican and Central American
Land Snails of the Family Cyclophoridae

Fred G. Thompson1
(Plates I-VII; Text-figures 1-14)

The systematics of some Middle American cyclophorid snails is revised based on studies
of the soft anatomy. Two subfamilies are recognized ( Aperostominae and Neocyclotinae)
as occurring in Mexico and Central America, not including the Diplommatinid genus
Adelopoma. The subfamilies are separated by characteristics of the male and female
reproductive systems. Genera placed in the Aperostominae include Aperostoma, Megalo-
mastoma , Farcimen, and Tomocyclus. Genera placed in the Neocyclotinae include Dicrista
new genus (type species— D. liobasis n. sp. ), Xenocyclus new genus (type species— A" patulus
n. sp.), Amphicyclotus, and Neocyclotus. The following new species and subspecies are
also described: Dicrista flavescens n. sp., D. indentata n. sp., D. rugosa n. sp., Amphi-
cyclotus texturatus spiralis n. sp., A. paulsonoriun n. sp., Neocyclotus simplicostus n. sp.,
N. capscelius n. sp., N. ( Incidostoma ) impressus n. sp. The following nomenclatorial
changes are made: Mexcyclotus petersi petersi Solem change to Dicrista petersi (Solem);
M. p. damianensis Solem changed to D. damianensis (Solem); Cyclotus cooperi Tryon
changed to D. cooperi (Tryon). Cyclostoma lutescens Pfeiffer is considered a nomina
dubia. The generic name Mexcyclotus based on lutescens as genotype become unavailable
for use among Mexican taxa.

THE purpose of this study is to present new
information bearing on the systematics
and distributions of some Mexican and
Central American cyclophorid snails based on
material collected during recent years. The ma-
terial includes numerous specimens preserved
for anatomical investigations, and alters previ-
ous systematic concepts. The study is not com-
prehensive, and includes only critical synony-
mies for particular species and genera. For a
complete review of the taxa within this region
the reader is referred to papers by Bartsch and
Morrison (1942), Morrison (1955), and Solem
(1956).

Introduction

The Cyclophoridae are typical of many groups
of neotropical land snails. Although many spe-
cies are known, more await to be discovered.
Most of those that are known are represented
by only a few specimens each. Distribution data
are sparse or absent for most species. Large

1 Florida State Museum, University of Florida,
Gainesville, Florida 32601.

geographic areas from which material may be
expected remain unexplored for mollusks. Very
little is known about individual or geographic
variation, and much less is known about the
anatomies of the various species.

The classification of the cyclophorid mollusks
is as confused as that of any other comparable
division of land mollusks. There is no general
agreement whether the cyclophorids comprise
a single very large family, or whether several
distinct families are involved. Recent authors
tend to recognize the group as a superfamily
with several families, but no one has demon-
stated the presence of characters that consist-
ently separate and characterize the families. All
of the genera discussed in this paper are placed
in a single family and assigned to two sub-
families. This does not imply that I favor the
recognition of a single large family, the Cyclo-
phoridae, but only that I am hesitant to recog-
nize additional families until more is learned
about the soft anatomy of the various divisions.
Families or subfamilies in this group currently
are based, in part, on the geographic distribu-
tions of these categories, and this leaves much

35

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to be desired in explaining their origins, evolu-
tion, and relationships.

Early systems of classification divided the
helicoid cyclophorids into two subfamilies.
Those with a calcified operculum were placed
in the Cyclotinae, and those with a chitinous
operculum were placed in the Cyclophorinae.
The cylindroid genera were placed in several
different subfamilies on even lesser basis. This
system was modified by Kobelt (1902) and
Thiele (1929) who used geographic distribu-
tion as an important factor. All of the neo-
tropical genera were placed in a single subfamily
with the exception of Adelopoma , which belongs
in the subfamily Diplommatininae. Bartsch
(1942) recognized three subfamilies endemic to
the American tropics, but made no attempt to
differentiate them from Old World groups. These
subfamilies were based exclusively on shell and
opercular characters. The helicoid genera were
placed in the Aperostominae with a calcified
operculum, and the Amphicyclotinae with a
chitinous operculum. The cylindroid genera
were placed in the Megalomastominae.

Tielecke (1940) divided the cyclophorid
mollusks into five families, based primarily on
the anatomy of the reproductive systems. His
contribution is outstanding in that it was the
first and only comprehensive attempt to study
the soft anatomy of the cyclophorid mollusks.
The neotropical genera were placed in a single
family, the Poteriidae, characterized by possess-
ing a common duct for the copulatory bursa,
oviduct, and the seminal receptacle, and by hav-
ing the verge in males located on the center of
the nape or behind the right tentacle.

Recently Morrison (1955) studied the ex-
ternal male reproductive structures of the neo-
tropical members and placed them in two fami-
lies, the Amphicyclotidae and the Neocyclo-
tidae. The Amphicyclotidae was characterized
by having a seminal duct enclosed within the
verge. The Neocyclotidae was characterized by
having an open seminal groove extending to the
tip of the verge, and included two subfamilies,
the helicoid Neocyclotinae (= Aperostominae
and Poteriidae of other authors) and the cylin-
droid Neopupinae (= Megalomastominae) . He
related the Neocyclotidae to the Cyclophoridae
but derived the Amphicyclotidae from the
marine family Lacunidae. Solem (1957) dem-
onstrated that Amphicyclotus possesses a verge
that places it in the Neocyclotidae, and indicated
the nomenclatural changes that were necessary
if the West Indian “amphicyclotids” were rec-
ognized as a separate subfamily. Thompson
(1967) showed that this West Indian group is
related to the neocyclotids by the structure of

the female reproductive system, but differed
conspicuously in the tubular structure of the
verge, and recognized the group as the sub-
family Crocidopominae.

Recent field work in Mexico and Central
America has produced much new and interest-
ing material of the Cyclophoridae. This material
represents several new taxa and adds distribu-
tional data to some species that previously were
known from indefinite localities. Even more
important, most of the species collected are rep-
resented by soft parts, which provide new evi-
dences on the phylogeny of the group in Middle
America. New descriptions of four poorly
known species are also included.

Acknowledgment

Many people have assisted me in this study,
to all of whom I am grateful. For assistance in
field work in Mexico and Central America I
wish to thank Dennis R. Paulson and his wife
Mary Lynn, Washington State University; F.
Wayne King, New York Zoological Society; Roy
McDiarmid, Norman Scott, and Jay Savage,
University of Southern California; Andrew Star-
red, Los Angeles County Museum of Natural
History; Colin Little, University of Bristol; S.
David Webb, Florida State Museum, University
of Florida (UF). Albert Schwartz and Richard
Thomas, Miami, Florida, have provided me with
much valuable West Indian material. I wish to
thank the following people for the loan of speci-
mens in their charges. Tucker Abbott, Academy
of Natural Sciences, Philadelphia (ANSP);
Henry van der Schalie, Museum of Zoology,
University of Michigan (UMMZ); Harold A.
Rehder, United States National Museum
(USNM). Photographs of shells used in this
paper were taken by Ernest M. Collins, Jr.,
staff photographer of the Florida Division of
Plant Industries. Field work in Mexico and
Central America was supported by the National
Institutes of Health Research Grant GM 12300.

Family Cyclophoridae

The material that I have studied alters pre-
vious classifications of the neotropical cyclo-
phorids. All apparently lack a copulatory bursa
such as occurs in Cyclophorus (Tielecke, 1940:
321-327). I found no structure that appears
homologous to that organ of the Old World
cyclophorids. The absence of this organ indi-
cates a degree of unity among the American
genera that may justify recognition of them as a
single family, the Neocyclotidae. However, the
anatomical diversity of these genera oversha-
dows the common relationships suggested by the
absence of the bursa. The Megalomastominae
differs from all other cyclophorid groups by

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

37

having a long vaginal slit extending nearly the
length of the uterus. The subfamily is also pe-
culiar among New World groups in having a
multipapillaform seminal receptacle and a verge
located on the side of the head behind the right
tentacle. These last two characters suggest a
relationship with the Asiatic Pupininae (-idae).
Characters of the shell also suggest this rela-
tionship, but the Asiatic pupinids differ by hav-
ing a well developed copulatory bursa. Until
more is learned about the anatomy or the vari-
ous Asiatic pupinid genera, the relationship be-
tween the Pupininae and the Megalomastominae
will remain in question.

The Neocyclotinae and the Crocidopominae
are more alike to each other than to any other
comparable group of cyclophorids by having a
verge that is located on the center of the nape.
The Neocyclotinae has a stout verge that bears
an open seminal groove extending from the end
of the prostate to the tip of the penis. The
Crocidopominae has a long slender verge that
possesses a tubular seminal duct. Apparently
the Crocidopominae evolved from the Neocy-
clotinae. The emphasis placed on the distinction
between these two subfamilies may be ques-
tionable, but their relationships and their differ-
ences are clear in contrast to most other cyclo-
phorid subfamilies.

Subfamily Megalomastominae Kobelt
and Mollendorff

The external male reproductive structures of
the following species have been described:
Aperostoma m. mexicana (Menke)

(Tielecke, 1940: 339)
Aperostoma l walker i Baker

(Morrison, 1955: 152)
Tomocyclus simulacrum (Morelet)

(Bartsch and Morrison, 1942: 142)
Farcimen vindlense scopulorum T. and B.

(Torre and Bartsch, 1942: 34)
Farcimen superbum itinerium T. and B.

(Morrison, 1955: 152)
Farcimen ( Neopupina ) croteum (Gmelin)
(Bartsch, 1942: 44)
Megalomastoma pepiti Bartsch

(Bartsch, 1942: 48)
In addition I have examined both sexes of the
following species:

Aperostoma mexicana salleana (Martens)
Aperostoma palmeri (Bartsch and Morrison)
Farcimen ( Neopupina ) croteum (Gmelin)
This subfamily is characterized by having the
penis located on the side of the head behind the
right tentacle. The penis is broad and flattened
basally, and becomes cylindrical and attenuate
distally. An open seminal groove extends from

the end of the prostate and along the side of the
nape to the penis where it passes along the outer
and lower margin to the tip. The prostate has a
corresponding slit along its columellar margin.
The slit opens into the prostatic lumen and ex-
tends from the seminal duct to the anterior end
of the prostate where it continues with the
seminal groove on the nape.

The female has an open vaginal slit that ex-
tends almost the length of the uterus and is con-
tinuous with the uterine lumen. The uterus has a
single continuous lumen and is nuiltilobate along
its outer and distal margins. The copulatory
bursa is rudimentary or absent. The seminal re-
ceptacle consists of a series of digitiform or
grape-like glandular lobes that discharge into a
common chamber. The albumen gland is formed
by a simple loop in the oviduct and is attached
at its base by connective tissue to the side of the
bursa. The albumen gland enters into the cham-
ber of the seminal receptacle, which in turn
opens into the distal end of the vaginal slit. Both
the albumen gland and the seminal receptacle
are imbedded in muscle and connective tissue
and appressed to the side of the uterus.

In addition the subfamily has an unusually
enlarged hypobranchial gland, that occupies a
major portion of the surface of the pseudolung
(Text-fig. 1 ) .

The megalomastomids have in common a
multispiral, cornified operculum in which the
outer edges of the whorls overlap the succeed-
ing whorls and project obliquelly outward as
thin chitinous lamella. The innermost whorls
may be thickened but do not have calcareous
deposits. Although these opercular characteris-
tics do not distinguish this group, they show a
degree of uniformity among the member genera.

This subfamily consists of a homogeneous
group of genera that is confined to eastern
Mexico, Guatemala, and the Antilles. Aside
from the helicoid genus Aperostoma all of the
species are cylindroid in shape. This divergence
in shape is more apparent than significant, for
other features of the shell, such as the siphonal
notch and the reflected peristome, indicate a
close affinity between Aperostoma and Tomo-
cyclus, which have allopatric but contigous
ranges in eastern Mexico and Guatemala.

Tomocyclus

This genus has recently been reviewed
(Thomson, 1963). No additional material has
been examined.

Aperostoma mexicanum salleanum (Martens)
Cyclophorus salleanum von Martens, 1865;

Malak. Blatt., 12: 15 1 . — Strebel, 1873; Beit.

Mex. L. — Susswasser Couchy., I: 9; pi. 1,

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[54: 2

fig. 2; pi. 1A, figs. 2-2a. — Martens, 1890;
Biol. Cent. Amer. : 7-8. (Type locality:
Cordoba, Veracruz).

Cyrtotoma mexicanum salleanum (Martens),
H. B. Baker, 1922; Occ. Pap. Mus. Zool.
Univ. Mich., ( 106) :42-43; pi. 16, figs. 8-12.
Aperostoma mexicanum salleanum (Martens),
H. B. Baker, 1928; Occ. Pap. Mus. Zool.
Univ. Mich., (193) :51.

Cyrtotoma salleanum (Martens), Bartsch and
Morrison, 1942; Bull. U.S. Nat. Mus., 181;
170-171; pi. 22, figs. 19-21.

Aperostoma m. mexicanum (Menke), Solem,
1956; Proc. Acad. Nat. Sci. Phila., 108:48-50
{in part ) .

Veracruz: 2.9 mi. E. Cordoba, 2500' (UF
20211. 2); 1.9 mi. S.W., 0.8 mi. N. Fortin,

2900' (UF 20212 . 13); 4.3 mi. E. Cordoba,
2300' (UF. 19). Anatomical material examined
from the last two localities.

Male. The penis is located on the side of head
behind the right tentacle. The base of the penis
is bulbous; the distal end is about twice the
length of the base and is slender and flagellate.
An open seminal groove extends from the pros-
tate and along the side of the nape to the tip of
the penis.

Female. (Text-fig. 2, C) The single female
examined illustrates the general features of the
reproductive system, although the uterus does
not appear to be completely mature. The vaginal
slit extends the length of the uterus and is con-
tinuous with the uterine chamber. The uterine
chamber is uninterrupted through its length. The
outer margin of the uterus is convoluted into

Text-fig. 1. Aperostoma palmeri (Bartsch and Morrison). Dorsal and lateral view of the pseudolung and
associated organs showing the relatively large hypobranchial gland. Scale equals 5 mm.

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Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

39

many small lobes that decrease in size distally.
The distal end of the uterus is very thin and
spatulate, with weakly indicated lobation. The
seminal receptacle consists of about four digiti-
form glandular lobes that discharge into the
oviduct. The albumen gland consists of a simple
convoluted loop in the oviduct. The loop is at-
tached to the base of the seminal receptacle by
fine fibers of connective tissue.

Aperostoma palmeri (Bartsch and Morrison)
Cyrtotoma palmeri Bartsch and Morrison, 1942,
Bull. U.S. Nat. Mus., 181:172-173; pi. 22,
figs. 1-3. (Type locality: Gomez Farias,
Tamaulipas).

Aperostoma mexicanum palmeri (Bartsch and
Morrison), Solem, 1956; Proc. Acad. Nat.
Sci. Phila., 108:50-51; pi. 5, figs. 1-4, pi. 6,
figs. 1-5.

San Luis Potosi: 11.4 mi. E. Xilitla,

1100' (UF 20209. 31), (UF 20208. 11):
7.5 mi. E. Xilitla (UF 20210 .1). One female
and one male examined from first locality.

The material before me does not indicate
intergradation with A. mexicana as Solem (1956:
51 ) reported for material from the same region.
A. palmeri is readily distinguished from A.
mexicana by its deep parietal notch that is
open to the dorsal surface of the whorl as a
siphonal notch, and by its thickened, weakly
flaring peristome. The parietal notch is partially
obscured by a wing-like extension of the upper
lip which leaves a narrow slit connecting the
notch with the margin. A. mexicana has a more
broadly flaring peristome, and the parietal notch
consists of a simple U-shaped indentation that
lies along the parietal wall of the aperture, but
does not open through the dorsal wall of the
whorl as in a siphonal notch.

The nature Of the anatomical material is not
satisfactory for detailed studies, but does show
the gross morphological features of the repro-
ductive systems.

Male. Reproductive system typical for genus.
The penis is located on the side of the head be-
hind the right tentacle. The seminal groove ex-
tends from the prostate and along the side of
the nape to the tip of the penis. The groove is
uninterrupted along its course. The prostate lies
along the right margin of the pseudolung, and
appears to have an open seminal channel that is
continuous with the prostatic chamber and ex-
tends from the spermatoduct to the anterior end
of the prostate. The channel lies along the right
margin of the pseudolung, and terminates over
the seminal groove on the nape.

Female. The reproductive system is similar
to that described for A. mexicana salleana, ex-

cept that the uterus is more developed, and has
the same general appearance as does Farcimen
croteum.

Farcimen (Neopupima) croteum (Gmelin)

Puerto Rico: 2.5 mi. S.W. Yabucoa, 800'
alt. (3 females and 1 male); 1 km. S. Pueblito
de Ponce (4 females, 1 male).

Male. The verge is located on the right side
of the head behind the tentacle. It has an open
seminal groove that is continuous from the
prostate.

Female. The uterus (Text-fig. 2, A-B) is
large, robust, and glandular with numerous large
folds along its intestinal margin. The distal end
is conspicuously flattened and palmate. The
vagina consists of a continuous slit that extends
the length of the uterus, and has a very thin
membranous fold that overlaps the outer wall of
the uterus. The vaginal slit is continuous with
the uterine cavity, which continues distally into
the seminal receptacle. The receptacle consists
of a large mass of closely attached glandular
lobes that discharge individually or in small
groups into a chamber. The lumen of the re-
ceptacle is lined with numerous small folds that
ramify into the individual glandular lobes. The
albumen gland consists of a long sigmoid loop
in the oviduct that is closely attached by con-
nective tissue to the side of the seminal recep-
tacle in such a way that it is not distinguishable
from the receptacle lobes upon superficial exami-
nation. The ovary consists of five glands. The
first gland is a small, single digitiform structure.
Subsequent glands are multilobate.

The mantle is similar to that of Aperostoma
in that the hypobranchial gland is thick and
padlike, but is confined to the left side of the
pseudolung, is smaller, and is kidney-shaped.

Subfamily Neocyclotinae Kobelt and
Mollendorff, 1898

This subfamily includes the neotropical gen-
era that Morrison (1955) placed here, plus the
genera that he included in the Amphicyclotidae,
exclusive of those that are now placed in the
Crocidopominae (Thompson, 1967: 15). The
subfamily also includes the seven Pacific Island
genera discussed by Clench (1949: 4-13) and
Solem (1959: 180-184).

The subfamily Neocyclotinae is characterized
by possessing a verge that is located on the center
of the nape. An open seminal groove extends
from the end of the prostate, across the nape,
and to the tip of the verge. In some species of
one genus ( Neocyclotus ) the groove may be
secondarily coalesced to form a sperm duct that
is connected to the surface of the verge by a
keratinized raphe. This condition is different

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[54: 2

uterus

seminal rec.

oviduct
albumen gland

vaginal slit

Text-fig. 2. Female reproductive systems of two species of Aperostominae. A. Farcimen croteum
(Gmelin); 2.5 mi. s.w. Yabucoa, Puerto Rico. B. Farcimen croteum (Gmelin); enlarged view of seminal
receptacle with the receptacle chamber partially opened. The albumen gland has been partially freed
from the side of the receptacle. C. Aperostoma mexicana salleana (Martens); 4.3 mi. e. Cordoba, Veracruz.
Scale for A equals 5 mm; scales for B and C equal 2 mm.

from the sperm duct that occurs in the Croci-
dopominae, which has a tubular verge without
any connecting raphe between the sperm duct
and the outer surface. The female system is dis-
tinct in possessing a hollow saculate seminal
receptacle, an albumen gland that consists of an
enlarged segment in a loop of the oviduct, and
in having the uterine lumen divided longitudi-

nally into two chambers by an involution. The
division is generally incomplete so that a horse-
shoe shaped cavity is formed in cross-section,
but in one genus ( Neocyclotus ) the involution
completely divides the lumen except at the distal
end of the uterus. A copulatory bursa is absent
or is rudimentary and imbedded in the uterine
wall.

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Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

41

seminal

Text-fig. 3. Diagramatic illustrations of three types of female reproductive systems in the evolution of the
Neocyclotinae. A, C, and E are longitudinal sections through the uterus. B, D, and F are cross-sections
through the above utera at the points indicated by the arrows, and show the respective degrees of involu-
tion of the uterine wall. A. A primitive condition in which the seminal receptacle and the oviduct are
separate and discharge on the outer surface of the uterus, as in Dicrista new genus. C. A more advanced
stage in which the seminal receptacle enters the oviduct, and the genital duct terminates at the end of
the vagina, as in Amphicyclotus. E. A highly modified stage in which the genital duct enters the uterus
prior to the vagina. The uterine lumen is completely divided by an invagination so that a single sigmoid
passage occurs through the uterus from the genital duct to the vagina.

Evolution within the subfamily involved vari-
ous elaborations of the terminal structure of the
verge and modification of the female reproduc-
tive system. Features of the shell and the oper-
culum have no relationship to underlying ana-
tomical changes. Suprageneric categories based
upon conchological characters are without basis,
for several prominent external features occur
independently throughout the subfamily (color
patterns, siphonal notches, calcified opercula,
etc.) .

In the primitive condition the seminal recep-
tacle has a long slender duct that is independent
of the oviduct throughout its length and both
ducts discharge on the outer surface of the
uterus above the vagina (Text-fig. 3, A). In
more advanced stages the receptacle duct dis-
charges into the oviduct, forming a common
genital duct below their union, and the genital
duct terminates at the vaginal opening (Text-fig.
3, C) or into the terminal segment of the uterine
lumen (Text-fig. 3, E).

Among the Middle American genera Dicrista
new genus possesses the most primitive condi-
tion, (as in Text-fig. 3, A-B) which is only

slightly modified in Xenocyclus new genus.
Amphicyclotus (as in Text-fig. 3, C-D) is in-
termediate in structure between Dicrista and
Neocyclotus (as in Text-fig. 3, E-F). Presum-
ably other American genera are similar to Neo-
cyclotus. Ostodes Gould and Gonatoraphe
Mollendorff are the only members among the
Pacific island genera that have been investigated
sufficiently to indicate the structure of their
female reproductive systems (Solem, 1959: ISO-
184). They too are similar to Neocyclotus.

Mexcyclotus lutescems (Pfeiffer)
Cyclostoma ( Cyclophorus ) lutescens Pfeiffer,
1851; Proc. Zool. Soc. Lond.: 250.
Cyclophorus lutescens (Pfeiffer), Pfeiffer, 1852;

Monogr. Pneum. Viv., 1:82.

Mexcyclotus lutescens (Pfeiffer), Bartsch and
Morrison, 1942; Bull. U.S. National Mus.,
(181): 179 (not 181).

Apparently this is a South American species
that has been identified with a form occurring
in Mexico. A brief review of its history is given.
Pfeiffer (1851: 250) described lutescens from
Brazil. He subsequently (1865: 69) recorded

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[54: 2

lutescens from Panistlahuaca, Oaxaca, on the
basis of material collected by Boucard. Fischer
and Crosse (1886: 139) included lutescens in
the Mexican fauna on the basis of Pfeiffer’s
identification of Boucard’s specimens. Angas
(1879: 483) recorded the species from the
Nicoya Peninsula of Costa Rica. Martens (1890:
7) hesitantly accepted the Costa Rican record
and suggested the identity of Cyclotus cooperi
Tryon from Mexico with Cyclostoma lutescens
Pfeiffer. Bartsch and Morrison (1942: 181)
recognized the two species as distinct, but they
included both in the Mexican fauna, and desig-
nated a new genus, Mexcyclotus, with lutescens
as the type species. Solem (1956: 55) synonym-
ized cooperi with lutescens, and discussed its
distribution in Mexico and Central America.

Apparently the sole basis for including lutes-
cens in the Mexican fauna is Pfeiffer’s citation
of specimens from Panistlahuaca, Oaxaca.
Later authors followed Pfeiffer and credited the
identity of the Mexican form to lutescens, but
at no time did Pfeiffer state that the original
locality of Brazil was in error, though implied
by von Martens (1890: 7). The identity of
Angas’s Costa Rican record is also doubtful.
Von Martens accepted the locality as probable
because it was bracketed by records from Brazil
and Mexico, but he did not accept some of
Angas’s other Costa Rican cyclophorid records
(Martens, 1890: 4).

An important distinction between lutescens
and Mexican forms, or their identity, depends
upon the opercular structure of the type of
lutescens. All authors on Mexico subsequent to
Pfeiffer ( 1865) assumed that Mexican popula-
tions called lutescens have an operculum similar
to that described for the Brazilian specimens.
The types of lutescens currently lack opercula
(J. F. Peake, personal communication), but
some important points are stated in the original
description (Pfeiffer, 1851: 250). A translation
is given below.

“Shell umbilicate, depressed conical, solid,
obliquely threadstriate, silky (shiney), yellow-
ish white; spire low and conical, acute; suture
deep, simple; whorls 4.5, convex, rapidly in-
creasing, last whorl not descending; umbilicus
moderate, deep; aperture slightly oblique,
broadly ovate; peristome simple, sharp, con-
tinuous, narrowly adnate, upper corner weakly
angulate. — Operculum membranous, pale horn
colored, coarse and spiral [lamella], outer sur-
face deeply concave. - Major diameter 20 mm,
minor diameter 15.5 mm, height 12 mm, aper-
ture height 10 mm.”

“Habitat in Brazil.”

Several critical points are apparent. The shell
is more depressed than any Mexican specimens
identified as lutescens by recent authors. The
shell is unusually large, has unusually few
whorls, and the whorls rapidly increase in size
in contrast to Mexican specimens identified as
lutescens. The operculum is described as being
rough and membranous, not calcified. Similar
observations on the operculum were made by
von Martens ( 1 890: 2) and Kobelt (1902: 254)
who had both examined Pfeiffer’s types. Kobelt
merely stated that the operculum was mem-
branous and tightly coiled.

All authors subsequent to Pfeiffer assumed
that Mexican specimens identified as lutescens
have a membranous operculum as described
by Pfeiffer. Actually they do not. The Mexican
forms all have a well developed oblique cal-
careous lamella in addition to a chitinous la-
mella. The differences in opercular structure
between lutescens and cooperi precludes their
specific or generic identity. Because of these
differences the name Mexcyclotus must be re-
stricted to the “Brazilian” species (lutescens) ,
and the Mexican species (cooperi and others)
must be placed in a separate genus described
below.

Even if we assume that the original locality
given for lutescens was in error, but that the
name applies to a Mexican species and that
Pfeiffer omitted important points in his descrip-
tion of the operculum, the name cannot be
clearly identified with any Mexican form, for
Pfeiffer’s description fails to mention charac-
teristics of the embryonic sculpture which would
be necessary to restrict the name among known
taxa.

Dicrista new genus

Type Species: Dicrista liobasis new species.

A neotropical genus of cyclophorid snails
superficially characterized by the combination
of characters of its shell and operculum, and
more fundamentally by the characters of the
male and female reproductive systems. The shell
is variable in size and shape. It is usually heli-
coid or depressed helicoid; occasionally very
depressed. The shell has about five whorls at
maturity. The whorls slowly increase in size.
The umbilicus is variable in size, but always less
than 0.30 times the major diameter. The sculp-
ture is simple, consisting of axial threads or
riblets. In some instances the axial sculpture
may be quite heavy and rugose, but it is always
simple, and follows the line of growth, not anas-
tomosing or oblique or otherwise modified. The
axial sculpture may begin on the second embry-
onic whorl in one group of species or it may

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

43

not appear until after the third whorl in another
group. The aperture is generally simple, hut
two species have a small siphonal notch in the
upper corner.

The operculum is highly variable within the
genus (PI. I and Text-fig. 4), but always con-
sists of a chondroid basal plate with a calcareous
and a chitinous lamella on the outer surface.
The basal plate may he simple or it may be
laminated with calcareous deposits. The lamella
may be simple, oblique, and overlapping, or they
may be nearly vertical and highly modified for
particular species. The operculum is usually
concave in cross section and consists of about
nine to ten closely coiled whorls.

The male possesses a stocky, moderately flat-
tened verge that ends in a simple rounded or
bluntly pointed tip, and has a small triangular
penis on the dorsal surface (Text-fig. 5). The
penis lies near the right margin and is reflected
posteriorly. A low sigmoid lateral fold lies along
the outer margin of the penis. An open seminal
groove originates on the side of the nape at the
anterior end of the prostate, and continues along
the ventral surface of the verge, and back along
the inside surface of the lateral fold. The inner
wall of the prostate, as in the uterus of the
female, is lined with a thick layer of glandular
tissue that is involuted mesially to produce a
large pendulous glandular fold that divides the
prostatic lumen into two cavities that are con-
nected mid-ventrally by a narrow gap.

The uterus is elongate, cylindrical, and of
nearly uniform width throughout its length
(Text-fig. 6). The interior of the uterus is lined
with a thick glandular layer that is involuted
mesially to form a large pendulent fold which
divides the uterine lumen into two lateral
chambers that are interconnected mid-ventrally
by a narrow gap. The vagina consists of a small
slit located on the columellar side of the anterior
end of the uterus, and is continuous with the
uterine lumen. The seminal receptacle is a small
saculate pouch appressed against the distal end
of the uterus. It has a thick brown glandular
wall, and has a simple muscular duct that is
split along one side near its base. The albumen
gland consists of a large sigmoid loop in the
oviduct. The base of the loop is closely bound
by connective tissue to the distal sixth of the
uterus. Both the oviduct and the receptacle duct
are partially imbedded in the uterine wall, and
terminate just above the vagina beneath a thick
fleshy flap on the columellar side of the uterus.
The two ducts discharge into separate narrow
grooves in the wall of the uterus. The grooves
are parallel to the vaginal slit and are not inter-
connected.

The genus is known to occur in southwestern
Mexico. It questionably has been recorded from
Costa Rica. Dicrista contains seven known spe-
cies representing two species groups that are
distinguished by the sculpture on the early
whorls of the spire. One group, containing the
type species, has strong axial ribs on the second
embryonic and following whorls. The other
group does not develop axial sculpture until after
the third whorl. The groups parallel each other
in modifications of other characters of the shell
and operculum. I consider the typical group
with sculptured embryonic whorls to be the most
specialized, and derived from the more gen-
eralized smooth-whorled stock. Species of the
latter group have also undergone a high degree
of specialization, but along individual lines and
not as a group.

Dicrista and the following genus form an
isolated stock that is not closely related to other
genera of the subfamily Neocyclotinae, because
of the structure of the reproductive systems.

The generic name Dicrista is derived from the
Latin and refers to the two opercular lamella,
one calcareous and one chitinous. The name is
of the feminine gender.

Dicrista cooperi (Tryon)

Cyclotus cooperi Tryon, 1863; Proc. Acad. Nat.
Sci. Phila., 1863: 281; pi. 2, fig. 2. (Type
locality: nr. Mazatlan, Sinaloa).

Mexcyclotus cooperi (Tryon), Bartsch and
Morrison, 1942; Bull. U. S. Nat. Mus., 181:
180; pi. 24, figs. 10-12.

Mexcyclotus lutescens (Pfeiffer), Bartsch and
Morrison, 1942; Bull. U. S. Nat. Mus., 191:
181; pi. 24, figs. 13-15.

Mexcyclotus lutescens (Pfeiffer), Solem, 1956;
Proc. Acad. Nat. Sci. Phila., 108: 55-56;
pi. 5, figs. 12-13, 16.

Diagnosis. A species of Dicrista allied to
liobasis, damianensis, and flavescens, and dis-
tinguished from others by its rugosely sculp-
tured embryonic whorls. It differs from the first
three species by its moderately small size, conical
shape, closer sculpture on the early whorls, and
narrower umbilicus. It approaches damianensis
in these characters, and may be subspecifically
related. The primary differences between the two
forms are in the smaller shell, lack of a sub-
sutural chord, and flattened operculum of
cooperi.

Shell (PI. II, A-C). Small or medium sized.
Solid, but not thick. Helicoid; height 0.67-0.95
times major diameter. (The holotype is unusu-
ally depressed. All other specimens examined
have a height/width ratio greater than 0.70).

44

Zoologica: New York Zoological Society

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Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

45

Spire conical, straight-sided or weakly convex.
Color dull brown with darker streaks along
growth lines. Whorls regularly and relatively
slowly increasing in size; minor diameter 0.79-
0.83 times major diameter. Whorls uniformly
rounded, not shouldered; not noticeably de-
scending near aperture. Suture deeply impressed,
without subsutural chord. Umbilicus narrow,
0.16-0.20 times major diameter. Whorls 4.4-5. 3
in mature specimens. Embryonic whorls 1. 8-2.0;
protruding. First embryonic whorl smooth, 0.8
mm. in diameter perpendicular to initial suture.
Next embryonic with strong, rugose, oblique

riblets. Following whorls with similar riblets
that become more closely spaced and less dis-
tinct until on last whorl or so the sculpture
consists of numerous close, sharp axial threads
and striations, which continue only slightly
diminished across the ventral surface of the body
whorl and into the umbilicus. Aperture circu-
lar, slightly higher than wide; 0.45-0.49 times
major diameter. Narrowly attached to but not
indented by previous whorl. Advanced at the
parietal margin; oblique in lateral profile. Pari-
etal callus moderate, opaque. Peristome simple,
sharp. Interior of aperture white.

Text-fig. 5. Verges of Dicrista new genus and Xenocyclus new genus. A. D. liobasis new species, dorsal
view of head and nape with the verge bent forward to show the seminal groove. B. D. liobasis new species,
dorsal view of verge. C-D. D. rugosa new species, topotype. E-G. D. flavescens new species, holotype,
G is a view of the right margin of the verge showing the coarse of the furrow under the penis. H-I. .Y. patulus
new species, topotype. Scales equal 5 mm; scale under A for that figure only; scale at bottom of page
for all others.

46

Zoologica: New York Zoological Society

[54: 2

receptacle
duct

uterus

Text-fig. 6. A. Dicrista liobasis new species, ventral view of uterus and associated organs; topotype.
B. Dicrista liobasis, enlarged view of lower half of uterus showing terminations of the genital ducts beneath
a flap of tissue. C. Dicrista liobasis, cross-section of uterus A at point indicated by arrow. D. Xenocyclus
patulus new species, ventral view of uterus and associated organs, topotype. Scales equal 5 mm.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

47

Measurements in mm of six specimens of D

. cooperi

are:

Maj. Diam.

Min. Diam.

Height

LJmbil.

A per. H.

A per. W.

15.8

12.8

12.1

—

1A

7.1

type

17.5

—

14.0

-

8.2

8.2

ANSP

74555

14.5

—

13.7

-

7.0

6.9

USNM

251718

16.1

12.9

13.2

2.9

7.5

7.5

15.0

11.8

11.6

3.0

7.1

6.9

14.0

11.4

11.7

2.2

6.9

6.8

Operculum (PI. I, B; Text-fig. 4, A). Con-
sisting of eight to nine whorls in large specimens.
Nucleus depressed, forming a low mound on
inner surface. Basal chondroid plate partially
laminated with calcareous deposits. Chitinous
spiral lamella lying at an oblique angle. A nar-
row, calcareous spiral lamella lies against the
underside of the chitinous lamella, and extends
nearly as far out as the latter. Outer edge of
calcareous lamella simple, though overlapping
succeeding whorl.

Specimens Examined. Sinaloa: nr. Ma-
zatlan (ANSP 13019 — type and paratype of
Cyclotus cooperi Tryon); Rosario (ANSP
74555. 5). Jalisco: Hacienda de Istapa

(USNM 251718. 13); San Sebastian (USNM
251717. 1). Colima: 7.6 mi. N.N.E. Man-
zanilla, 200' (UF 20190. 8). Guerrero:
Zihuatenejo (E1SNM 517886. 1), (ANSP

194612. 4). Oaxaca: no specific locality

(ANSP 13021. 3), ( MCZ 136023. 1). Costa
Rica: no specific locality (ANSP 13020. 2).

Remarks. Solem (1956: 55) recorded a
specimen (ANSP 184033) from near Zihuate-
nejo, Guerrero. This and two others from near-
by localities (UF 20204, UF 20205) are not
identifiable as cooperi because of their notably
heavier and larger shells, but cannot be placed
elsewhere because they are weathered speci-
mens that lack sculptural details and opercula.

I am not satisfied that other specimens listed
from Guerrero, or those from Oaxaca and Costa
Rica, are identifiable with this species or that
they represent authentic records. These lots con-
sist of only one or a few specimens, and are
unsatisfactory for critical comparison. The
specimens cited from Zihuatenejo, Guerrero,
( USNM 517886) cannot be satisfactorily identi-
fied with or distinguished from cooperi. They are
mostly immature, broken, and lack opercula.

Specimens that bear such locality data as
"Oaxaca” and "Costa Rica” defy verification
about the authenticity of their data.

The confusion of cooperi with Mexcyclotus
lutescens has been discussed under that species.

Dicrista damianensis (Solem)
Mexcyclotus petersi damianensis Solem, 1956;

Proc. Acad. Nat. Sci. Phila., 108; 57-58; pi.

5, fig. 11; pi. 6, figs. 13, 18.

Diagnosis. A species of Dicrista related to
cooperi, liobasis, and flavescens by its rugosely
sculptured embryonic whorls. It is distinguished
by its depressed helicoid shape, narrow umbili-
cus, the presence of a subsutural chord, its larger
size, and its deeply dished operculum.

Shell (PI. Ill, D-F). Medium sized. Dull
light brown. Moderately thick for genus. De-
pressed-helicoid, height 0.67 times major diam-
eter. Spire conical; very slightly convex on out-
line. Whorls regularly increasing in size; minor
diameter 0.76 times major diameter. Whorls
nearly uniformly rounded, dorsal surface slop-
ing. Umbilicus funicular, 0.20 times major diam-
eter. Fast whorl descending near the aperture.
Suture deeply impressed, slightly channeled
along suture. Subsutural chord very weakly in-
dicated. 4.8 whorls. Embryonic whorls 1.8;
raised, but only moderately protruding. First
whorl 1.0 mm in diameter; smooth. Following
3A whorl with strong, widely spaced riblets. Fol-
lowing whorls with coarse thread-riblets that
become more closely spaced and less well de-
fined with growth of shell. Thread riblets only
slightly diminished in texture on ventral surface
of body whorl. Aperture width 0.41 times major
diameter. Parietal callus thick, opaque. Paris-
tome simple, sharp, moderately arched along
dorsal surface; oblique in lateral profile. Interior
of aperture dull white.

Measurements in mm of the holotype of D. damianensis are:

Maj. Diam. Min. Diam. Height Umbil.

Aper. H.

Aper. W.

20-8 15.7 14.6 4.3

9.1

9.0

48

Zoologica: New York Zoological Society

[54: 2

Operculum (PI. I, C; Text-fig. 4, B). Con-
sisting of about 10 closely coiled whorls. Coni-
cal; deeply dished in cross-section. Basal
chondroid plate weakly laminated with calca-
reous deposits. Chitinous spiral lamella moder-
ately thin and broken away along its edge.
Underlying calcareous lamella moderately thick,
oblique, and overlapping so that outer face of
operculum is predominantly calcified in appear-
ance.

Type Locality. Michoacan, 1 mile north of
San Pedro Damian Naranjestilla (18° 18' N,
103° 8' W). Holotype: UMMZ 184837; col-
lected by James A. Peters (only known speci-
men).

Remarks. This species was described orig-
inally as a subspecies of D. petersi (Solem). D.
daniianensis differs from petersi in so many
respects, including the nature of the opercular
structure, the absence of a siphonal notch, and
the presence of axial sculpture on the second
embryonic whorl, that even a close specific rela-
tionship is not tenable.

D. daniianensis is closely related to D. co-
operi as is discussed under that species. It is
also closely related to D. liobasis. It differs from
liobasis by having a more deeply dished opercu-
lum, a narrower umbilicus (about 0.20 times
major diameter), a more elevated spire, a more
deeply impressed suture, coarser and closer
thread riblets on the second and third whorl,
having the sculpture continue scarcely dimin-
ished across the ventral surface of the body
whorl, and by lacking a distinct subsutural chord.

Dicrista liobasis new species

Diagnosis. A species of Dicrista related to
cooperi, daniianensis, and flavescens because of
the costulate sculpture on the embryonic whorls.
It is distinguished by its very depressed helicoid
shape, its concave spire, its suture which is only
moderately impressed, its broad umbilicus, and
its narrow aperture. Some of these characters

are shared with one or two of the other species,
but liobasis is distinguished from all by the sculp-
ture on its last whorl. The sculpture consists of
thread-striations on the dorsal surface, which
become obsolete at the periphery leaving the
ventral surface and the umbilicus smooth. The
opercular characteristics described below also
tend to characterize liobasis.

Shell (PI. Ill, A-C). Medium sized. Moder-
ately thin. Very depressed helicoid; height 0.58-
0.63 times major diameter. Spire concave. Color
light brown with slightly darker radial streaks
due to periostracal fringes on the ribs. Suture
moderately impressed. A moderate subsutural
chord is present. Umbilicus broadly open, 0.25-
0.29 times major diameter. Whorls regularly
increasing; minor diameter 0.72-0.78 times ma-
jor diameter. Whorls nearly uniformly rounded,
slightly flattened dorsally. Body whorl descend-
ing slightly near the aperture. Whorls 4. 6-5.0 in
large specimens (4.7 in holotype). Embryonic
whorls 1.7; protruding so that spire is concave
in outline. Diameter of first whorl 0. 9-1.0 mm
perpendicular to initial suture. First whorl
smooth; following 3A whorl with strong uniform,
widely spaced thread-riblets that are most de-
veloped along the upper suture. Following two
whorls with uniformly spaced thread-riblets that
become more closely spaced on the body whorl.
Thread-riblets with low periostracal fringes.
About % riblets/mm on penultimate whorl.
Thread-riblets becoming obsolete below periph-
ery of body whorl. Ventral surface and
umbilicus smooth and shiny with incremented
striations. Aperture subcircular, usually slightly
higher than wide; narrowly attached to preced-
ing whorl. Aperture 0.40-0.43 times major
diameter. Parietal region slightly advanced,
thick, weakly translucent. At the most the aper-
ture is only slightly indented by the previous
whorl. Peristome simple, slightly arched forward
above periphery; moderately oblique in lateral
profile. Interior of aperture dull white.

Measurements in mm of seven specimens of D. liobasis are:

Maj. Diam.

Min. Diam.

Height

Umbil.

A per. H.

Aper. W.

22.1

16.6

12.9

6.0

9.1

9.3

holotype

21.4

15.8

13.4

6.0

8.7

8.5

paratype

21.7

16.1

12.8

6.3

9.2

8.9

paratype

22.1

16.0

13.4

5.5

9.4

9.2

paratype

21.1

16.5

13.3

5.1

9.5

9.1

paratype

20.6

15.6

13.0

5.7

8.1

8.4

paratype

19.0

14.1

11.4

5.2

8.4

8.0

paratype

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

49

Operculum (PI. I, D; Text-fig. 4, C). Con-
sisting of about nine to ten whorls in large speci-
mens. Weakly concave with a central depres-
sion. Nuclear region with a small knob on inner
surface. Basal chondroid plate thin and inter-
laminated with thin calcareous deposits. Calca-
reous lamella paralleling chitinous lamella, but
thicker and more resistant so that outer surface
of operculum may appear completely calcified.
Calcareous lamella deeply implanted into chiti-
nous structure of operculum.

Male. The verge (Text-fig. 5, A-B) originates
on the middorsal region of the nape and is ovate
in cross-section. When retracted the verge lies
under the mantle and is directed posteriorly. The
distal end of the verge terminates in a broad but
flat triangular point. A triangular penis is folded
back along the dorsal surface of the verge and
is directed toward the base. The end of the penis
is flattened and bluntly rounded. The penis bears
along its dorsal margin a smaller fleshy convolu-
tion in which the seminal groove terminates.
The seminal groove extends the length of the
verge. It lies on the ventral surface of the basal
half of the verge, and curves along the lateral
margin of the penis to where it ends in the
lateral fold on the side of the penis.

The verge of this species is characterized by
the simple structure of the penis, which lacks any
accessory modification, except for the lateral
fold. It is also characterized in lacking any pa-
pillae, grooves, or other modifications.

Female. The uterus (Text-fig. 6, A-C) is
elongate and nearly cylindrical in cross-section.
The vaginal slit is confined to the anterior tip
of the uterus along the columellar margin, and
continues into the uterine lumen. The uterine
walls are lined on the internal surface with a
thick glandular layer that forms a large pen-
dulous fold that extends nearly across the lumen
of the uterus. The fold divides the lumen into
two chambers that are interconnected by a nar-
row gap along the ventral margin, and extends
the length of the uterus. The outer surface of
the uterus and its distal margin are creased by
the arrangement of the internal glandular
masses. The anterior end of the uterine wall also
contains a small lobate yellow glandular mass
that lies lateral and slightly distal to the vaginal
slit. The oviduct has an elongate sigmoid loop
that forms the seminal receptacle, and is at-
tached at its base by connective tissue to the
distal fourth of the uterus. The seminal recep-
tacle contains a small yellow grandular mass
in its distal loop. The seminal receptacle lies
appressed to the ventral side and distal end of
the uterus. It is an elongate saculate structure
that is brown in color with a thick glandular wall.

The oviduct and the seminal receptacle have
separate ducts that extend to the anterior fourth
of the uterus where they discharge independently
under a thick fleshy flap on the columellar mar-
gin. The distal end of the receptacle duct is split
along its lateral margin beneath the flap and
discharges into a narrow, shallow groove. The
end of the oviduct is truncate and discharges into
a similar narrow groove that parallels the bursal
groove. These two grooves tend to lie parallel
to the vaginal slit, and the three structures are
not interconnected.

Type Locality. Jalisco, a limestone sink 6.0
miles southwest and 6.6 miles east of Pihuamo;
2000 feet elevation. Holotype: UF 20194;
collected 3 August, 1966 by Fred G. Thompson.
Paratypes: UF 20195 (13), UF 20196 (11).
UMMZ 216546 (4); same locality as the
holotype.

The type locality is at the base of a huge
limestone sink that lies atop a hill overlooking
the valley of the north tributary of the Rio
Tuxpan. The vegetation in the area consists of
dry scrub forest with little ground cover. Snails
were found in debris and leaf mulch around
limestone boulders.

Remarks. This species is superficially similar
to D. flavescens. See the latter species for a dis-
cussion of the differences between the two. D.
liobasis is also similar to damianensis (Solem)
on the basis of its opercular structure. They are
alike in having thin basal plates with calcareous
laminations, and with predominate oblique
calcareous lamella on the outer surface. They
differ as is discussed under D. damianensis.

Dicrista flavescens new species

Diagnosis. A species of Dicrista related to
liobasis , cooperi , and damianensis because of
costulate sculpture on the embryonic whorls. It
is distinguished by its yellowish brown color, its
depressed-helicoid shape, its sculpture consist-
ing of dense thread-striations that continue un-
diminished into the umbilicus, its wide umbilicus,
its narrow aperture, and its dorsally flattened
whorls. The most important characters special to
flavescens are in the structure of the operculum,
which consists of a thick basal chondroid plate
lacking calcareous lamination, and possessing
thick, resistant chitinous, and calcareous spiral
lamella on the outer surface. Features of the
verge described below are probably also pe-
culiar to the species.

Shell. (PI. II, G-I). Medium sized. Moder-
ate in thickness. Depressed helicoid; height 0.67-
0.72 times major diameter. Periostracum yel-
lowish brown. Spire uniformly conical. Whorls
regularly increasing in size; minor diameter

50

Zoologica: New York Zoological Society

[54: 2

Measurements in mm of the four specimens of D. flavescens comprising the type series are:

Maj. Diarn.

Min. Diam.

Height

Umbil.

A per. H.

A per. W.

18.8

14.3

13.0

4.9

8.0

8.1

holotype

21.2

16.1

13.3

6.0

9.1

8.8

paratype

19.8

14.7

12.5

5.6

8.0

8.0

paratype

18.1

13.3

11.3

5.2

7.7

7.6

paratype

0.74-0.76 times major diameter. Suture deeply
impressed. Subsutural chord weakly developed.
Whorls nearly uniformly rounded, flattened
dorsally. Last whorl not descending near the
aperture. Umbilicus funicular, showing all pre-
vious whorls; 0.26-0.29 times major diameter.
Whorls 4.9-5. 1 (5.0 in holotype). Embryonic
whorls 1.5. First whorl 0. 8-1.0 mm in diameter
perpendicular to initial suture; raised; smooth.
Following half whorl with uniform, evenly
spaced radial riblets. Remaining whorls with nu-
merous close radial threads that bear low cuticu-
lar fringes. Radial threads continuous and hardly
diminished into umbilicus. Aperture nearly cir-
cular; narrowly attached to preceding whorl,
which only slightly indents aperture. Parietal
callus moderate, glassy, transparent, slightly ad-
vanced. Aperture moderately oblique in lateral
profile; 0.40-0.43 times major diameter. Peri-
stome simple, sharp, nearly planular. Interior of
aperture white.

Operculum (PI. I, E; Text-fig. 4, D). Con-
sisting of about nine whorls in large specimens.
Shallowly dished in cross-section. Nuclear re-
gion with a small knob on inner surface. Basal
chondroid plate thick, not interlaminated with
calcareous deposits. Thick chitinous lamella ex-
tending obliquely outward and turned nearly
vertically upward at its outer edge. Calcareous
lamella lying parallel to and along underside of
chitinous lamella. Upturned ends of chitonous
and calcareous lamella forming a raised spiral
ridge on face of operculum.

Male. The verge (Text-fig. 5, E-G) originates
on the center of the nape immediately beneath
the mantle collar, and when retracted is directed
posteriorly and to the left within the mantle
cavity. The verge is lanceolate in shape with a
slight constriction near its middle, and is nar-
rowly ovate in cross-section. The verge ends in
an obtuse point, and has a flat triangular wing-
like penis that lies on its dorsal side and is di-
rected back toward the base of the verge. The
penis bears a small low lateral fold on its outer
margin in which the seminal groove terminates.
A deep furrow lies on the dorsal side of the
verge and passes obliquely under the penis. The
distal left third of the verge bears numerous

small conical papillae that occur in a restricted
zone on the dorsal and ventral surfaces.

Female. None examined.

Type Locality. Guerrero, 7.8 miles south of
Mazatlan; 3500 feet altitude. Holotype: UF
20197; collected 28 June, 1966 by Fred G.
Thompson. Paratypes: UF 20198 (3); same
data as the holotype.

The type locality lies on a limestone hillside
along a ravine cut by a tributary to the Rio
Omiltan. The area is rugosely karsted. The vege-
tation consisted of a lush, dense second growth
of shrubs, vines, and small trees. Snails were
found in leaf mulch around limestone boulders.

Remarks. This species is similar to D. lio-
basis, but differs from it in numerous respects.
The most apparent differences between the two
species are in the nature of the shell sculpture,
the spire, the suture, and the operculum. D.
flavescens has a dull luster with very close radial
threads bearing cuticular fringes. The threads
continue undiminished across the ventral surface
of the body whorl and into the umbilicus. D.
liobasis has more widely spaced fringed thread-
riblets on the first four whorls. These transform
into irregular cuticular threads on the last whorl.
The threads and thread-riblets do not continue
across the ventral surface of the body whorl,
which is smooth and shiny. The embryonic
whorls of flavescens are not conspicuously
raised, and the spire has a simple, depressed,
conical outline. The embryonic whorls of lio-
basis protrude, causing the spire to be concave
in outline. The suture of flavescens is deeply im-
pressed, due to the more elevated, uniformly
conical spire. The suture of liobasis is only mod-
erately impressed, due to the flattened, concave
spire.

More important, but less conspicuous, are dif-
ferences in the operculum and the male repro-
ductive systems. The operculum of flavescens is
strongly concave, and has a thick chondroid
basal plate that lacks calcareous laminations.
The chitinous lamella is relatively thick and
resistant to wear. The calcareous lamella is also
relatively thick and erect, and is not deeply
implanted into the chitinous structure. The oper-
culum of liobasis is depressed-conical in cross-

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

51

section, and has a relatively thin basal chondroid
plate that is interlaminated with calcareous de-
posits. The cuticular spiral lamella is thin and
weak, and is generally eroded away, leaving a
nearly naked calcareous outer surface formed
by the thin, oblique calcareous lamella, which is
deeply imbedded into the chitinous structure.

The verge of flavescens is unique in the genus
by possessing minute conical papillae along its
distal margin extending beneath the reflected
penis flap.

Dicrista indentata new species

Diagnosis. A species of Dicrista lacking
sculpture on the embryonic and upper whorls of
the spire, relating it to petersi and rugosa. It is
distinguished by its small size, its helicoid shape,
the presence of a siphonal notch that develops
only after growth of the fourth whorl, and a
strong subsutural chord. The operculum is dis-
tinct within this group of species by its relatively
simple laminated structure with oblique calca-
reous and chitinous lamella. The calcareous
lamella is peculiar in that it possesses a spiral
groove along its outer margin caused by the over-
hanging free edge.

Shell (PI. II, D-F). Small. Moderately
thick. Light brown in color. Helicoid; height
0.66-0.84 times major diameter. Spire moder-
ately raised, convex in outline. Umbilicus funicu-
lar, showing all previous whorls; 0.21-0.27
times major diameter. Whorls slowly and regu-
larly increasing in size; minor diameter 0.75-
0.83 times major diameter. 4. 5-5. 2 evenly
rounded whorls in large specimens (5.0 in holo-
type). Body whorls slowly descending to the
aperture. Suture deeply impressed with body
whorl loosely attached to preceding whorl. The
loosely attached suture along the last whorl is
caused by the progressive growth of the si-
phonal notch, which does not appear until after
the shell has acquired about four or more
whorls. A conspicuous subsutural chord is also
present along all postembryonic whorls, and lies
outside of the subsutural groove along the last
whorl. Embryonic whorls 1. 5-2.0; protruding.
First whorl 0.80-0.95 mm wide perpendicular
to initial suture. Embryonic and first postembry-
onic whorls smooth. Following whorls with reg-
ular, fine, slightly rugose ribs that become
narrower, sharper, and reduced but distinct on
the base and in the umbilicus; about 4-6 ribs/
mm on the dorsal surface of the last whorl. Aper-
ture nearly circular; slightly higher than wide.
Only slightly or not at all indented by previous
whorl. Aperture width 0.42-0.45 times major
diameter. Peristome complete across parietal
margin, but with a small siphonal notch at the
upper corner that is exaggerated by the sub-

sutural chord along its outer margin. Peristome
slightly oblique in lateral profile; planular. In-
terior of aperture dull white.

Measurements of the holotype: major diam-
eter, 16.5 mm; minor diameter, 12.3 mm; height,
11.8 mm; aperture height, 7.1 mm; aperture
width, 7.0 mm. The holotype is the largest nor-
mal shell examined. Larger specimens are geron-
tic in form.

Operculum (PI. I, F; Text-fig. 4, E). Con-
sisting of about nine to ten whorls in large speci-
mens. Center of operculum depressed, forming
a low knob over inner surface. Basal chondroid
plate thick near middle, interlaminated with cal-
careous deposits near outer surface. Chitinous
spiral lamella extending obliquely outward. Cal-
careous lamella deposited outside of chitinous
lamella and forming a parallel spiral band. Cal-
careous lamella with a spiral groove along out-
side margin, formed by overhanging free edge
of lamella.

Type Locality: Michoacan, 10.0 miles

southeast of San Vicente, 200 feet elevation.
Holotype: UF 20191; collected 31 May, 1966
by Fred G. Thompson. Paratypes: UF 20192
(36), UF 20193 (15), UMMZ 216845 (5);
same locality as the type.

The type locality lies in low rolling hills that
extend out toward the Pacific Ocean as a low
limestone range. The vegetation consisted of a
submesic forests with little ground cover, except
for recently fallen leaves and debris. Snails were
collected from around limestone boulders and
from under logs and debris.

Remarks. This species is similar in appear-
ance to cooperi from which it differs in several
respects, most important of which is the embry-
onic sculpture. In indentata the embryonic
whorls, as well as the next whorl or two, are
smooth. Any sculpture at all consists only of
fine, irregular incremental striations. Distinct
axial thread-riblets do not appear until -after at
least the third whorl. In cooperi strong regularly
spaced-riblets appear on the second embryonic
whorl, and continue around the spire where they
become closer and finer. The difference in em-
bryonic sculpture place indentata and cooperi
in different species groups. D. indentata is also
distinct by having a siphonal notch in the parie-
tal margin of the aperture, by having a loosely
attached body whorl due to a groove formed by
the growth of the siphonal notch, by having a
well developed subsutural groove, and by having
a spiral groove along the outer side of the cal-
careous opercular lamella.

D. indentata is similar to D. petersi because of
the development of a siphonal notch in both spe-
cies late in the growth of the shell. Besides the

52

Zoologica: New York Zoological Society

[54: 2

very different structures of the opercula, inden-
tata is readily recognized by its small size, nar-
rower umbilicus, and its holicoid shape.

Dicrista petersi (Solem)
Mexcyclotus petersi petersi Solem, 1956; Proc.

Acad. Nat. Sci. Phila., 108: 56-57; pi. 5, fig.

9; pi. 6, figs. 14-17.

Diagnosis. A large species of Dicrista lacking
sculpture on the upper three to four whorls of
the spire, relating it to indentata and rugosa. It
is distinguished by its large size, depressed heli-
coid shape, channeled suture, siphonal notch,
and weakly convex operculum with a strong
calcareous lamella that has a flat base with its
outer margin turned vertically upward along the
succeeding chitinous lamella. The chitinous la-
mella is high, strong, resistant to wear, and is
weakly sigmoid.

Shell (PI. IV, A-D). Large; solid. Shell de-
pressed-helicoid; height 0.64 times major diam-
eter. Spire low and straight sided. Color light
brown with occasional darker streaks along lines
of growth. Umbilicus funicular; 0.30 times ma-
jor diameter. Suture moderately impressed, and
deeply channeled by a groove formed by the
siphonal notch. Groove accentuated by a spiral
chord along its outer margin. Whorls regularly
increasing in size; minor diameter 0.74 times
major diameter. Whorls rounded; dorsal surface
sloping. Last whorl not descending to aperture.
Apparently 5.2 whorls in holotype prior to when
apical whorl was lost. Embryonic whorls about
1.75; smooth. Following two whorls also smooth,
but with very fine incremented striations that
become increasingly stronger. Body whorl sculp-
tured with incremental thread-striations that be-
come increasingly prominent toward the aper-
ture, but are very reduced on the ventral surface
and indistinct in the umbilicus. Aperture nearly
circular, slightly higher than wide; narrowly at-
tached to preceding whorl. Aperture width 0.39
times major diameter. Parietal callus thin and
translucent. A strong siphonal notch indents the
upper corner. The siphonal notch is accentuated
by a shallow groove along its outer margin inside
of the aperture. This groove lies beneath the end
of the subsutural chord on the outer surface of
the shell. Peristome simple, vertical in lateral
profile. Interior dull white.

Operculum (PI. I, G; Text-fig. 4, F). Con-
sisting of ten whorls. Inner six whorls closely
coiled; outer whorls more loosely coiled. Weakly
convex with outer margins turned upward. Basal
chondroid plate thick; very weakly laminated
with calcareous deposits. Nuclear region slightly
depressed on outer surface. Chitinous spiral la-
mella nearly erect, and sigmoid with its edge
directed laterally. Calcareous lamella thick and
flat with its outer margin turned upward along
succeeding chitinous whorl. Surface of calca-
reous lamella with rugose spirally oblique stria-
tions.

Type Locality. Michoacan, La Placita
( = Sulatillo) ( 18° 32' N, 103° 37' W). Holo-
type: UMMZ 184836, collected 5-9 July,
1950 by James A. Peters. Paratype: ANSP
194642 (juvenile); same data. Only known
specimens.

Remarks. This species is known only from
the holotype and an immature paratype. The
characteristics used to distinguish the species are
consistent in both specimens. Its relationship to
D. indentata and D. rugosa are discussed under
those species respectively.

Dicrista rugosa new species

Diagnosis. A large species of Dicrista related
to petersi and indentata by lacking costulate
sculpture on the upper three to four whorls of
the spire. It is characterized by its very de-
pressed helicoid shape, only moderately im-
pressed suture lacking a subsutural channel or
chord, light brown color that fades to dirty white
on the last half of the body whorl, rugose costu-
late sculpture on the last whorl, and a simple
peristome lacking a siphonal notch. The opercu-
lum is characteristic in being moderately con-
cave, with a strong erect calcareous lamella that
lies against the preceding chitinous lamella. The
chitinous lamella is weak and is generally eroded
away leaving a nearly bare calcified outer surface
to the operculum.

Shell (PI. IV, E-G). Large, solid. Shiny.
Color light brown, tending to fade to white on
last half of body whorl. Very depressed helicoid;
height 0.63-0.67 times major diameter. Spire
straight-sided or only very slightly concave in
outline. Umbilicus funicular, showing all pre-
vious whorls; 0.24-0.29 times major diameter.
Suture only moderately impressed due to low

Measurements

in mm of the holotype of D. petersi are:

Maj. Diam.

Min. Diam. Height Umbil.

A per. H.

A per. W.

25.4

18.8 16.2 7.9

11.0

10.0

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

53

Measurements in mm of six specimens of D. rugosa are:

Maj. Diam.

Min. Diam.

Height

Umbil.

A per. H.

A per. IV.

24.8

19.5

15.5

6.1

11.2

10.8

holotype

24.4

18.7

15.5

7.0

10.3

10.2

paratype

22.5

17.8

15.2

5.4

10.1

9.9

paratype

26.8

21.2

17.0

7.4

11.4

1 1.2

UF 20203

25.7

19.6

16.3

6.9

11.0

10.7

UF 20203

25.0

18.7

15.0

7.2

10.7

10.7

UF 20203

spire. Subsutural chord absent. Whorls regu-
larly increasing in size; minor diameter 0.75-0.79
times major diameter. Last whorl descending
near the aperture, particularly in large animals,
though the descent may not be conspicuous in
specimens with fewer than 4.8 whorls. Whorls
nearly uniformly rounded, slightly flattened
dorsally. Whorls 4. 7-5. 3 in large specimens (4.9
in holotype). Embryonic whorls 2. 0-2. 2; mod-
erately protruding. First whorl 1 .0-1.1 mm in
diameter. Embryonic whorls smooth. Following
two whorls also smooth but with fine irregular
incremental striations. Body whorl with irregu-
lar rugose ribs that become increasingly strong
near the aperture, but are poorly defined on the
ventral surface, and indistinct in the umbilicus.
Aperture circular, slightly higher than wide;
narrowly attached to but not indented by pre-
ceding whorl. Aperture width 0.42-0.46 times
major diameter. Parietal callus moderate and
opaque. Peristome simple, oblique in lateral pro-
file. Interior of aperture white.

Operculum (PI. I, H; Text-fig. 4, G). Con-
sisting of about eight whorls in large specimens.
Moderately concave in cross-section. Nuclear
region thick, but without knob on inner surface.
Outer surface with thick high vertical calcareous
spiral lamella that is partially lined on its inner
surface by a thin chitinous lamina which gener-
ally is eroded away. Outer side of calcareous
lamella concave. Basal chondroid plate thick,
without calcareous lamination.

Male. The verge (Text-fig. 5, C-D) orig-
inates on the center of the nape immediately be-
neath the mantle collar. The verge is stocky and
narrowly ovate in cross-section with a bluntly
rounded tip. The penis consists of a small lobate
flap, and a larger acuminate lateral fold along
the outer margin. The seminal groove terminates
on the inner side of the acuminate lateral fold.

Female. None examined.

Type Locality. A small limestone knoll 11.4
miles east of Colima, Colima; 1800 feet altitude.
Holotype: UF 20199; collected 28 May, 1966
by Fred G. Thompson. Paratypes: UF 20200
(11); same data as the type.

Other Specimens Examined. Colima: hill
10.0 mi. S. Colima (UF 20201. 5), (UF 20202.
2) ; 1 1 .4 mi. S. Colima (UF 20203. 16). These
specimens are all dead and bleached shells, some
of which retain partially deteriorated opercula.
They are like the type specimens in size, shape,
sculpture, and opercular characters, except that
the last series of specimens (UF 20203) tends
to be more depressed. The specimens examined
for anatomical studies were from the type lot.

Remarks. This species is distinct within the
genus because of its large size, smooth sculpture
on the spire, and rugose sculpture on the body
whorl. It is similar to D. petersi (Solem) on the
basis of its size, smooth spiral whorls, and cal-
careous lamella of the operculum, but differs
from that species by lacking a siphoral notch and
a channeled suture, and by having rugose cos-
tulate sculpture on the body whorl. D. petersi
has a well-developed siphonal notch that forms
a subsutural groove, which in turn is accentu-
ated by a raised spiral chord along its outer mar-
gin. The sculpture on the body whorl consists of
incremental thread striations. In D. rugosa the
operculum is concave, laminated, and the cal-
careous lamella is erect along the preceding
chitinous lamella. In D. petersi the operculum
is convex, unlaminated, and the calcareous la-
mella has a flat base with its outer margin erect
along the succeeding chitinous lamella. D. ru-
gosa also differs from D. petersi by having a
slightly smaller aperture and a slightly wider
umbilicus.

Xenocyclus new genus

Type Species: Xenocyclus patulus new species.

A neotropical genus of cyclophorid snails
closely related to and derived from Dicrista ,
but having so many peculiar features that it
warrants separate generic status. The shell is
moderately large and depressed dome-shaped.
The umbilicus is very wide, being one third or
more the major diameter of the shell. The whorls
are of correspondingly small caliber and slowly
increase in size, with five or more whorls in
adult specimens. The sculpture consists of fine

54

Zoologica: New York Zoological Society

[54: 2

thread striations on the lower whorls. In the only
known species the sculpture is obsolete on the
ventral surface and absent in the umbilicus. The
most distinctive feature of the genus is the pres-
ence of a deep, narrow tear-shaped siphonal
notch in the upper corner of the peristome. The
notch is not open dorsally, but continues back
along the suture as a siphonal tube that is nearly
completely enclosed, being narrowly open only
along the suture of the earlier whorls. The
siphonal notch and resulting siphonal tube be-
gin with the first postembryonic whorl.

The operculum (PI. I, A; Text-fig. 4, H) is
similar to some species of Dicrista, except that
it is an even more elaborate modification than
that which occurs on D. petersi and D. rugosa.
The operculum is strongly convex in cross-
section, consisting of about 12 tightly coiled
whorls. The outer surface bears a nearly vertical
calcareous lamella and a slightly higher chi-
tinous lamella that are free from each other.

The male reproductive system is similar to
that of Dicrista. The verge (Text-fig. 5, H-I)
originates on the center of the nape, and has an
open seminal groove that runs from the end
of the prostate, across the nape and along the
verge to its tip. The end of the verge has a
simple triangular penial flap reflected posteriorly
with the seminal groove terminating in a small
lateral convolution.

The female reproductive system (Text-fig. 6,
D) is similar to that of Dicrista and other neo-
cyclotids, but is peculiar in having a segmented,
glandular seminal receptacle duct that has a
narrow central lumen. Both the receptacle duct
and the oviduct discharge through a single small
pore on the outer surface of the uterus about
one fifth of the length of the uterus above the
vaginal slit.

The genus is monotypic and is currently
known from a single locality in the coastal lime-
stone ranges of Colima.

The generic name is derived from the Greek
^cvog, meaning strange and kl’kAo?, meaning
circular, or more exactly its affinities with the
cyclophorid snails. The name Xenocyclus re-
flects the strange combination of siphonal and
opercular characters. The name is of the mas-
culine gender.

Xenocyclus is closely related to Dicrista. It
is separated because of its highly developed and
closed siphonal notch and tube, depressed dome-
shaped shell, strongly convex operculum with 12
whorls, and segmented glandular seminal recep-
tacle duct that opens through the same pore as
does the oviduct. D. petersi might be considered
intermediate between the two genera because of

its open siphonal notch, deep groove along the
suture, and weakly convex operculum, but I
am disposed to regard these as independent
evolutionary trends. The development of a
siphonal notch is a rather plastic character
among neotropical cyclophorids. It is highly
variable within genera ( A perostoma , Tomocy-
clus, and Incidostoma ) and similar structures
may develop independently even among closely
related forms {Tomocyclus simulacrum and
T. gealei). Thus, the similarities between D.
petersi and X. patulus do not necessarily reflect
phylogenetic affinity. Other features of the shell
and operculum suggests that D. petersi is much
closer in its relationships to non-siphonate forms
of Dicrista. The numerous differences between
Xenocyclus and Dicrista indicate an extensive
evolutionary transition of Xenocyclus from the
primitive dicristid lineage.

Xenocyclus patulus new species
Shell (PI. V, A-D). Medium to large. Solid
but not particularly thick. Depressed dome-
shaped. Spire slightly raised above last whorl;
more elevated in old and gerontic specimens.
First embryonic whorl elevated, rapidly increas-
ing in size. Following half whorl constricted and
depressed with succeeding whorls being nearly
planular. Fleight 0.53-0.65 times major diam-
eter. Shiny. Color light brown with lighter and
darker streaks that parallel growth lines. Nuclear
whorls when present nearly white. Umbilicus
very wide, 0.33-0.38 times major diameter.
Whorls of small caliber, slowly increasing in
size; minor diameter 0.75-0.84 times major
diameter. Whorls nearly uniformly rounded;
dorsal surface somewhat flattened and sloping.
Last Vi whorl descending rapidly to the aper-
ture. Suture very shallow; partially interrupted
by a nearly completely covered siphonal tube
that parallels the suture. Siphonal tube formed
by a deep narrow tear-shaped siphonal notch in
the upper corner of the peristome. It begins in
the first postembryonic whorl and continues un-
interrupted to the aperture. The tube is not com-
pletely sealed over, but is narrowly open along
some portions of the suture, particularly along
the upper whorls. Whorls 5. 0-5. 3. Embryonic
whorls 1.5-1. 7, smooth, generally broken away.
First whorl 0. 9-1.0 mm wide perpendicular to
initial suture. Whorls of spire nearly smooth,
sculpture with fine irregular incremental stria-
tions that become progressively stronger and
closer. Last 1.5 whorls with numerous close in-
cremental thread-striations that are recurved
along the suture, are very much reduced in tex-
ture on the ventral surface, and are obsolete in
the umbilicus. Aperture nearly circular, slightly
higher than wide; width 0.35-0.39 times major

Thompson: Some Mexican and Central American

1969] Land Snails of the Family Cyclophoridae 55

Measurements in mm of five specimens of X.patuhis are:

Maj. Diam.

Min. Diam.

Height

U mbit.

A per. H.

A per. W.

24.0

18.2

13.0

9.1

8.8

8.6

holotype

24.9

19.4

13.7

9.6

10.1

8.7

paratype

23.7

19.0

13.6

8.2

9.2

8.5

paratype

23.2

19.5

14.8

7.4

10.0

9.2

paratype

(gerontic)

22.5

17.5

13.5

8.2

9.1

8.7

paratype

diameter. Peristome simple, sharp, complete ex-
cept for a deep, narrow, tear-shaped siphonal
notch at the upper corner. Siphonal notch not
open dorsally, but continuing back along suture
as a siphonal tube. Upper-outer margin of peri-
stome arched forward. Parietal callus thin,
opaque. Interior of aperture white, with a
slightly livid tinge.

Operculum (PI. I, A; Text-fig. 4, H). Con-
sisting of about 12 closely coiled whorls in large
specimens. Basal condroid plate convex, with
outer lamellar fringe turned upward. Chondroid
plate with some small calcareous lenticular de-
posits. Nuclear region forming a low mound
on inner surface. Chitinous lamella turned
nearly vertically upward and forming a spiral
fringe free from underlying calcareous lamella.
Calcareous lamella thick at base and tapered
upward; weakly imbedded into chitinous
structure.

Male. The verge (Text-fig. 5, H-I) originates
on the center of the nape beneath the mantle
collar, and when relaxed is directed posteriorly
and to the left within the mantle cavity. The
verge is dorso-ventrally compressed and is about
thrice as long as wide. The distal end is bluntly
rounded and bears a triangular flap-like penis
that is folded back on the dorsal surface along
the right margin. The penis bears a thin fleshy
lanceolate appendage on its outer margin. The
distal fourth of the verge has a small zone of
low rippled papillae along its left margin. The
verge has many fine parallel creases elsewhere
along the margins. An open seminal groove
originates on the side of the nape at the end of
the prostate, and extends along the ventral
surface of the verge to the lateral appendage on
the penis where it terminates. The interior of
the prostate, as in the uterus of the female, is
lined with a glandular layer along its sides. The
glandular layer is involuted mesially to form a
large pendulous fold that divides the lumen into
two lateral chambers that are connected mid-
ventrally by a narrow gap.

Female. The uterus (Text-fig. 6, D) is
elongate-cylindrical and of nearly uniform diam-

eter throughout its length. The outer surface is
marked by numerous parallel creases that follow
the pattern of the underlying glandular masses.
The interior of the uterus is like that of Dicrista.
The sides of the lumen are lined with a thick
layer of glandular tissue that is involuted mesi-
ally to form a thick pendulous glandular fold
that divides the lumen into two lateral chambers
which are connected mid-ventrally by a narrow
gap. The vaginal slit is located at the anterior
end of the uterus and is continuous with the
uterine lumen. The seminal receptacle consists
of a small brown sac that is appressed against
the end of the uterus. The receptacle walls con-
sist of a thick glandular layer of tissue that ex-
tends the length of the duct as a weakly seg-
mented glandular stalk with a narrow flat lumen.
The albumen gland consists of a large sigmoid
loop in the oviduct. The base of the loop is
closely bounded by connective tissue to the distal
sixth of the uterus. The loop is flattened and
laterally expanded to form a saculate albumen
gland. Both the oviduct and the receptacle duct
are partially imbedded in the uterine wall, and
discharge through a single pore that consists of
a lobate fold on the side of the uterus and is
located about Vr, of the length of the uterus
above the vaginal slit. The ovary consists of a
few large digitiform and weakly dendritic glan-
dular clusters.

Type Locality. Colima, a collapsed lime-
stone ridge 0.3 miles southeast of Tamala; 500
feet altitude. Holotype: UF 20185; collected
2 August, 1966 by Fred G. Thompson. Para-
types: UF 20186 (7), UF 20187 (7), UF
20188 ( 10), UMMZ 216547 (3); same locality
as the holotype.

The type locality is a collapsed limestone ridge
consisting of large blocks and boulders of lime-
stone. The vegetation along the ridge consists
of an open xeric scrub forest that lacks ground
cover. Snails were found around the bases of
limestone boulders in damp leaf mulch. This is
the same locality and station as that from which
I collected a new genus and species of helicinid
snail, Ceocliasma phrixina (Thompson, 1968).

56

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[54: 2

Remarks. This species is immediately dis-
tinguished from all other neotropical cyclo-
phorids by the presence of a nearly completely
closed siphonal tube along the suture. It is also
distinguished by its large size, depressed shape,
large umbilicus, and strongly convex operculum
with 12 whorls. As striking as are these features,
relationships are not obscured.

Amphicyclotus Crosse and Fischer, 1879
Amphicyclotus Crosse and Fischer, 1879; Journ.
de Conchyl., 27:46. — Bartsch and Morrison,
1942; Proc. U. S. Nat. Mus., 181:183-184.
(Type species: Cyclostoma ( Cyclophorus )
boucard: [Salle] Pfeiffer, 1856).
Amphicyclotus as used in this paper includes
only the typical group related to the type species,
A. boucardi (Pfeiffer). The genus may also in-
clude Megacyclotus, Barbacyclus, and Calacy-
clotus as subgenera or lesser categories (Solem,
1956: 43; see also Bartsch and Morrison, 1942:
175-186 for definitions of these generic groups).
A discussion of the status of these groups is
beyond the limitations of the anatomical mate-
rial currently available. The shell characters
used to separate them are distinctive enough to
allow consistent recognition, but the emphasis
placed on these characters is subjective. Prob-
lems of relationships cannot be resolved until
anatomical studies are made of the last three
"genera.”

In the course of this study I have examined
the anatomies of three species of Amphicyclotus.
The species show a surprising degree of diversity
in some aspects of the female reproductive sys-
tem, but in other aspects of both male and
female systems they show a degree of uniformity
that is characteristic for the genus.

The prostate (Text-fig. 7, C) is relatively
simple, with a narrow lumen that forms a broad
U caused by a thick glandular ridge along the
columellar margin. The verge (Text-fig. 7, A-B;
Text-fig. 8) is located on the center of the nape
beneath the mantle collar. It is dorso-ventrally
flattened, and is directed posteriorly with its
distal end recurved anteriorly. The tip of the
verge has a funicular tip through which the semi-
nal groove terminates. A moderate bulge is
located along the inner margin of the tip of the
verge. The bulge and the funicular tip form the
penis. An open seminal groove extends from
the end of the prostate, diagonally across the
nape and along the verge to the tip of the penis.

The uterus (Text-fig. 9) is elongate-fusiform,
and has a narrow U-shaped lumen divided by a

thick glandular pendulent fold. The vagina con-
sists of a slit in the anterior third of the uterus.
The oviduct and the seminal receptacle have a
common duct along the columellar margin of
the uterus. The duct has an open groove extend-
ing its length and terminates at the vagina. The
duct is partially imbedded in the uterine wall
and has a small saculate vestibule at its distal
end. The seminal receptacle consists of a series
of convoluted tubules that usually forms a com-
pact mass on a short duct, but may be imbedded
in the wall of the vestibule. The oviduct enters
the common duct either at its end on the vesti-
bule, or near the middle of the duct (Text-fig.
10). The oviduct forms a sigmoid loop near the
end of the uterus. The distal bend of the loop
is enlarged into a saculate albumen gland.

Amphicyclotus is distinguished anatomically
by the nature of the common genital duct and
the seminal receptacle. Close relationships to
other genera are not indicated. The genus ap-
pears to be a Middle American assemblage of
species that is characteristic of the Chiapas-
Guatemala-Flonduras region, with some species
occurring in adjacent areas of Veracruz and
Oaxaca. Evolution within the genus appears to
have centered about modifications of the female
reproductive system, and secondarily about shell
characters. For this reason it is difficult to dis-
cuss the phytogeny of species that are known
only from shells, for similarities of external
characters frequently are not substantiated by
anatomical data.

Amphicyclotus t. texturatus (Sowerby)
Cyclostoma texturatus Sowerby, 1850; Thesau-
rus Conchyliorum, Suppl.: 160; pi. 31 A, fig.
303. (Type locality: Guatemala)
Amphicyclotus texturatus (Sowerby); Fischer
and Crosse, 1880; Miss. Sci. Mex. et dans
l’Ameriq. Cent., vol. 2, pt. 7; pi. 35; figs.
2-2b. — 1886, ibid.; 144. — Bartsch and Mor-
rison, 1942; Bull. U. S. Nat. Mus., 181:186;
pi. 24, figs. 1-3. — Solem, 1956; Proc. Acad.
Nat. Sci. Phila., 108:45.

Cyclophorus ( Amphicyclotus ) texturatus (Sow-
erby), Martens, 1890; Biol. Cent. Amer.: 6.
Type Locality. Herein restricted to Coban,
Alta Verapaz, Guatemala.

Guatemala ( Dept. Alta Vera Paz) : Finca
Chichen (UMMZ 149481. 1 ); Finca de la
Providencia (UMMZ 86029. 1 ) ; 3 km. W. Finca
Samac (UMMZ 132316. 1). No Specific Lo-
cality: (UMMZ 86033. 1), (UMMZ 86034.
1), (UMMZ 86644. 1), (UMMZ 35762. 1).

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

57

Text-fig. 7. Male reproductive structures of Amphicyclotus and Barbacyclus. A-C. A. t. spiralis new
subspecies, topotype. A, B. Dorsal and ventral views of verge. C. Prostate and associated structures.
D. B. princeps (Pilsbry), ventral view of the verge. E. B. princeps (Pilsbry) an enlargement of the distal
portion of the verge and penis. Scales for B-D equal 5 mm; scale for E equals 1 mm.

58

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[54: 2

Text-fig. 8. Verges of three species of Amphicyclotus showing dorsal (A, C, E) and ventral (B, D, F)
views. A-B. A. parvus Thompson, paratype. C-D. A. megaplanus Morrison. E-F. A. paulsonorum new
species, topotype. Scales equal 3 mm; scale for A also for B-D; scale at bottom for E and F.

Measurements in mm of seven specimens of A.t. texturatus are included so that this subspecies
can be compared with the following new subspecies:

Maj. Diam.

Min. Diam.

Height

Umbil.

A per. H.

A per. W.

Cat. No.

29.4

21.1

17.3

7.6

8.3

7.9

149481 (imm.)

45.1

30.5

22.4

12.8

16.9

19.7

86029

37.8

26.5

21.1

11.2

15.6

15.5

132316

39.1

28.0

19.7

12.0

15.8

16.8

35762

36.8

26.4

19.2

11.3

15.0

15.1

86033

36.7

26.8

20.6

10.2

14.8

15.0

86034

35.8

24.6

20.0

9.6

15.0

16.0

86644

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

59

Ratios are: minor diameter, 0.68-0.73 times
major diameter; height, 0.50-0.59 times major
diameter; umbilicus, 0.27-0.31 times major
diameter; aperture width, 0.41-0.45 times major
diameter.

A specimen that Solem (1956: 45) recorded
from Chiquihuite, Mt. Tacana, Chiapas, 6400
ft. (UMMZ 144244) does not belong to this
form, but represents an undescribed species,
characterized by its nearly smooth sculpture
and small size. The specimen is insufficient for
a taxonomic description.

Amphicyclotus texturatus spiralis

Diagnosis. A form assumed to be subspecifi-
cally related to A. texturatus (Sowerby). It
differs from texturatus by being smaller and by
having light spiral bands in the periostracum.
A. t. texturatus is unicolored. Since the anatomy
of A. t. texturatus is unknown it is not possible
to comment further on the degree of differentia-
tion of the two forms.

Shell ( PI. VI, A-C) . Moderately large. Light
brown with a rose tinted apex and with light
spiral bands, particularly along the periphery.
The bands differ in width and are irregular in
number. Some are always conspicuous along the
periphery and additional ones are clearly evi-
dent below the periphery. The bands are weakly
impressed as spiral lines into the vermiculate
sculpture. Generally depressed helicoid, al-
though some specimens may be nearly planular;
height of shell 0.59-0.70 times major diameter.
Spire weakly concave in outline. Whorls regu-
larly increasing in size, minor diameter 0.71-
0.78 times major diameter. Umbilicus funicular,
moderate, 0.24-0.28 times major diameter.
Suture impressed, but not channeled. Last whorl
descending slightly near the aperture. Whorls
5. 2-5. 5 (5.5 in holotype). About 2.2 embryonic
whorls; moderately raised, rounded, and with a
weakly impressed suture. First 1.7 embryonic
whorls smooth; following half whorl with weak
axial ribs that are most distinct along the suture.
The axial ribs continue onto the following
whorls, where they become stronger and tend

to become vermiculate on the third whorl. Re-
maining whorls with distinct but relatively weak
vermiculating sculpture that extends from the
suture to the umbilicus, where it becomes
slightly weaker. Vermiculations not conspicu-
ously interrupted by spiral bands in fresh speci-
mens. Aperture circular, oblique in lateral pro-
file; 0.42-0.47 times major diameter. Posterior
corner of aperture advanced. Peristone slightly
thickened and weakly reflected; connected across
parietal wall by a thick callus.

The type series encompasses nearly all varia-
tion in size and proportions seen among other
individuals.

Operculum. Typically amphicyclotid, con-
sisting of about nine chitinous whorls that
weakly overlap. The operculum is deeply dished,
with the nuclear region being slightly more
depressed.

Male (Text-fig. 7, A-C). The prostate is sub-
triangular in cross-section and is elongate-
tapered with its distal end flattened and wedge-
shade. The seminal duct enters the prostate at
the base of the wedge-shaped distal segment.
The seminal duct discharges directly into the
prostatic lumen, which is U-shaped because of
a thick glandular ridge along the columellar side
of the lumen. The anterior end of the prostate
is partially imbedded in the body wall, and opens
into a genital groove on the side of the nape.

The verge is located on the center of the nape
beneath the mantle collar and is folded poste-
riorly with its tip reflected anteriorly. The verge
is long and ponderous, with its distal end broadly
expanded and then tapering to a pointed funi-
cular tip. A small inconspicuous bulge occurs
on the right margin near the end of the verge.
The bulge and the funicular tip are homologous
to the penis of Dicrista. An open seminal groove
extends obliquely across the nape of the base
of the verge and follows a mid-course along the
ventral surface of the verge to its funicular tip.

Female (Text-fig. 9, D). The uterus is
elongate-fusiform with an expanded, flattened
distal end and a narrower, attenuate base. The

Measurements in mm of the six specimens comprising the type series of A. t. spiralis are:

Maj. Diam.

Min. Diam.

Height

Umbil.

Aper. H.

Aper. W.

32.0

23.5

19.2

7.8

14.0

15.0

holotype

33.2

23.3

—

8.9

14.1

14.6

paratype

30.4

21.7

17.9

8.5

13.2

12.8

paratype

29.6

21.7

18.7

7.3

12.9

13.4

paratype

28.9

21.0

17.8

7.2

12.5

13.3

paratype

27.8

21.5

19.6

7.2

12.8

12.0

paratype

60

Zoologica: New York Zoological Society

[54: 2

Text-fig 9. Female reproductive systems of three species of Amphicyclotus. A. A. paulsonorum new
species, topotype. B. Cross-section of uterus of A at point indicated by arrow. C. A parvus Thompson,
paratype. D. A. t. spiralis new subspecies, topotype. Scales equal 5 mm.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

61

uterine lumen is divided longitudinally by a
thick pendulous fold of glandular tissue that is
involuted from the columellar margin. The
vagina is about one-third the length of the uterus
and enters the lumen along the ventral base of
the internal glandular fold. The oviduct and the
seminal receptacle duct form a common genital
duct along the columellar margin of the uterus
(Text-fig. 10, C) . The duct is partially imbedded
in the uterine wall and has an open slit extending
from near its apex to the vagina. The apex is
slightly enlarged and forms a small vestibule
into which the receptacle and the oviduct dis-
charge independently. The oviduct forms a sig-
moid loop that is bound by connective tissue to
the distal sixth of the uterus. The distal end of
the loop is broadly expanded and forms a large
saculate albumen gland. The seminal receptacle
has a short duct and consists of a series of con-
voluted tubules that are bound by connective
tissue into a small ball.

Type Locality. A coffee grove 4.7 miles
north-northeast of Huixtla, Chiapas; 600 feet
elevation. Holotype: UF 20176; collected 23
July, 1966 by Fred G. Thompson. Paratypes:
UF 20177 (5); same data as the holotype.

Other Specimens Examined. Chiapas:
12.7 mi. N.N.E. Huixtla, 1500' (UF 20178.
17); 14.6 mi. N.N.E. Huixtla; 2100' (UF
20179. 2); near Escuintla (UMMZ 128945. 3).
Specimens for anatomical studies were taken
from the series comprising UF 20178.

This subspecies was common north of Huixtla
in quasi-rain forests, where specimens were col-
lected in leaf mulch and among organic debris.

Remarks. Solern (1956: 45) treated this
form as d. t. texturatus (Sowerby), but noted
the distinctive characteristics of its color pat-
terns. It is distinguished from A. texturatus by
its spiral banding. It also tends to be more
elevated and to have a narrower umbilicus, but
it overlaps the typical subspecies in these
characters.

Amphicyclotus paulsonorum new species

Diagnosis. A species of the typical subgenus
characterized by its small size, large umbilicus,
costulate sculpture on the second embryonic
whorl, and loosely convoluted seminal recep-
tacle.

Shell (PI. VI, D-F). Moderately small.
Solid, but not thick-walled. Periostracum uni-
form dull yellow-brown. Depressed-helicoid in

Text-fig. 10. Posterior view of terminal segments of the genital ducts and associated structures in three
species of Amphicyclotus. A. A. paulsonorum new species, topotype. B. A. parvus Thompson, paratype.
C. A. t. spiralis new subspecies, topotype. Scales equal 2 mm.

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[54: 2

Measurements in mm of six large specimens from the type series of A. paulsonorum are:

Maj. Diam.

Min. Diam.

Height

Uinbil.

A per. H.

A per. W.

20.5

15.0

13.5

5.0

9.2

9.2

holotype

20.5

15.5

13.7

5.4

8.9

9.0

paratype

20.1

14.8

13.0

5.2

8.7

8.7

paratype

20.0

14.6

13.1

4.8

9.5

9.2

paratype

19.4

14.2

12.7

4.6

8.8

9.0

paratype

19.0

14.6

11.7

5.0

8.3

8.2

paratype

shape; height 0.62-0.69 times major diameter.
Spire broadly conical, pointed; spire nearly
straight-sided. Umbilicus moderately wide, deep
and funicular, 0.23-0.27 times major diameter.
Whorls slowly and regularly increasing in size;
minor diameter 0.72-0.77 times major diameter.
Whorls flattened dorsally along the suture and
tending to be obsoletely angulate along the
periphery. Last whorl not descending near the
aperture. Suture deeply impressed, but not
channeled. Whorls 4. 6-5.0 (4.9 in holotype).
Embryonic whorls, 2.0; moderately protruding
and with a strongly impressed suture. First
embryonic whorl smooth; following whorl with
strong, close, moderately oblique ribs. Following
neanic whorl with stronger, more widely spaced,
and nearly vertical ribs that become wavy near
the suture. Remaining whorls with moderately
strong, vermiculated sculpture that forms
oblique wavy lines along the periphery and is
continuous into the umbilicus. Sculpture tend-
ing to be obsolete along the last Vi whorl, par-
ticularly on the base. Aperture circular, oblique
in lateral profile; interior white. Aperture width
0.43-0.46 times major diameter. Peristome
simple, narrowly interrupted across parietal
margin. Parietal callus moderate and opaque in
large individuals.

Operculum. Chitinous, consisting of about
eight vaguely distinguishable whorls that do not
overlap. Concave, with the nucleus depressed on
the outer surface and forming an obtuse blunt
point on the inner surface.

Male (Text-fig. 8, E-F). The male repro-
ductive system is similar to that of A. texturatus,
but differs in several characteristics of the verge.
The distal third of the verge is broadly expanded
so that the recurved penis is of minor impor-
tance in its mass. The funicular tip of the penis
lies along the inner margin facing the base of the
verge, and the penial bulge is large and lobate.

Female (Text-fig. 9, A). The nature of the
uterus and vagina is similar to that described for
A. texturatus and the genus in general. Features
peculiar to paulsonorum are in the structure of
the genital duct and its associated organs. The

duct is open throughout most of its length and
forms a moderately small vestibule at its distal
end. The seminal receptacle is large and con-
sists of a highly convoluted mass of tubules that
are loosely connected so that no compact struc-
ture is formed. (In Text-fig. 9, A, the receptacle
is folded upon itself so that its true relative size
is not indicated). The receptacle discharges
through a small duct into the apex of the vesti-
bule (Text-fig. 10, A). The albumen gland con-
sists of a moderately enlarged sacculate loop in
the oviduct, and has a relatively long duct that
enters the genital duct about midway between
the apex and the vagina.

Type Locality. A ravine 4.2 mi. N. W.
Escuintla, Chiapas; 300 feet altitude. Holo-
type: UF 20180; collected 24 July, 1966 by
Fred G. Thompson. Paratypes: UF 20181
(15), UMMZ 216549 (5); same data as the
holotype.

Other Specimens Examined. Chiapas:
21.3 mi. N. W. Huixtla, 300' (UF 20182. 17);
32.5 mi. N. W. Huixtla, 200' (UF 20184. 2);
10 mi. N. W. Pijijiapan, 100' (UF 20183. 6).
Alcoholic specimens for anatomical studies were
taken from the type series and the two locali-
ties northwest of Huixtla.

This species was collected in quasi-rain for-
ests. They were found crawling on debris and
leaf mulch after rains, and hiding in organic
trash during dryer weather.

Remarks. A. paulsonorum is similar to A.
texturatus spiralis in superficial appearance, but
differs in several aspects of the shell, including
its smaller size, fewer whorls, unicolor spire, and
lack of spiral bands. As far as is known the two
species are allopatric. They were suspected to be
subspecifically related until their soft anatomies
were examined. A. paulsonorum differs strik-
ingly from spiralis by its larger, loosely coiled
seminal receptacle, and by the origin of the
oviduct from the middle of the common genital
duct (Text-fig. 10, A, C). In spiralis the recep-
tacle is smaller and compactly coiled, and the
oviduct discharges into the apex of the common
genital duct behind the vestibule.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

63

The shell of paulsonorum is also similar to
that of A. parvus Thompson (1963: 20-22) and
A. maleri Crosse and Fischer (1883: 102).
A. parvus differs most notably in characteristics
of the sculpture. In that species the first IVi
whorls are devoid of any sculpture, except for
very fine, irregular growth striations. The fol-
lowing whorls have the characteristic vermi-
culate sculpturing as occurs in the genus, but
the sculpturing is very weak and shiny. A. paul-
sonorum has strong oblique axial ribs on the
second embryonic whorl and the following
whorl, and the vermiculated sculpture on the
remainder of the shell is strong, rugose, and
dull. A. parvus differs by even more striking
characteristics of the female reproductive sys-
tem. The copulatory bursa is vestigial and is
imbedded in the vestibular wall of the common
genital duct, and the oviduct originates from
the apex of the common duct (Text-fig. 10, B).

A. maleri, from Tabasco, differs from paulso-
norum by being considerably larger, by having
a reddish-violet apex, and by having the upper-
most 2.5 whorls smooth.

The specific epithet of A. paulsonorum is
proposed as an expression of gratitude to Dr.
Dennis R. Paulson and his wife Mary Lynn, who
discovered the species.

Amphicyclotus parvus Thompson
Amphicyclotus parvus Thompson, 1963; Proc.

Biol. Soc. Wash., 76: 20-22; pi: II, figs. 4-7.

Type Locality. Hacienda Monte Cristo,
Metapan, Santa Ana, El Salvador; 2200 meters
elevation. Holotype: UMMZ 195882. Para-
types: UMMZ 195881 (35); Senckenbergi-
schen Naturforschenden Gesellschaft 101151-6
(120).

No new material has been examined. The fol-
lowing anatomical discussions are based upon
animals extracted from the paratypes (UMMZ
195881), which were preserved in 70% alcohol
when collected.

Male (Text-fig. 8, A-B). The male repro-
ductive system is similar to that of A. texturatus.
It differs only by having a smaller “penial” bulge
along the right margin, and by having a more
pronounced funicular tip to the verge.

Female (Text-fig. 9, C). The female repro-
ductive system is similar to that of A. texturatus
except for the following characters. The distal
end of the genital duct forms a much enlarged
vestibule. The seminal receptacle is rudimentary,
being embedded within the wall of the vestibule
and is evident only as convoluted tubules within
the wall. The albumen gland is relatively smaller,
as is illustrated.

Amphicyclotus megaplanus Morrison
Amphicyclotus megaplanus Morrison, 1955;

Jour. Wash. Acad. Sci., 45: 160; figs. 29-31.

Morrison’s description is based upon a
bleached and worn adult (holotype) and an im-
mature paratype. The holotype (USNM 618777)
lacks the apical whorls, the operculum, and the
periostracum. The paratype (USNM 618778)
has worn apical whorls and lacks an operculum.
Material recently collected from near the type
locality reveals several important features not
evident or clearly represented in the type mate-
rial, and necessitates a redescription of the
species.

Shell. Large, solid, light brown with occa-
sional darker growth streaks. Planular, height
0.54-0.56 times major diameter. Spire broadly
conical and slightly elevated; sides of spire con-
cave. Apical whorls protruding. Whorls rapidly
increasing in size; minor diameter 0.70-0.78
times major diameter in large specimens. Um-
bilicus broad and revealing all previous whorls;
umbilicus 0.27-0.30 times major diameter.
Suture deeply impressed and channeled, par-
ticularly along last whorl, which rapidly de-
scends near the aperture. Whorls flattened and
sloping inward near the suture; uniformly
rounded around the periphery. About 5.3 or
more whorls in mature specimens (apex fre-
quently broken or eroded). About 2.0 embry-
onic whorls, which bare sparse, oblique, weak
axial riblets along the upper suture. Riblets con-
tinuing on following two postembryonic whorls.
Last 1.3 whorls with characteristic but weak
vermiculate sculpture that continues over the
surface of the whorl and into the umbilicus, but
may be obsolete on some parts of the base near
the aperture. The vermiculated sculpture may
be hardly noticeable in some specimens, particu-

Measurements

in mm of five specimens of A. megapla

nus are:

Maj. Diam. Min. Diam.

Height

Umbil.

A per. H.

A per. W.

42.0

32.5

22.5

12.6

16.0

18.0

holotype*

37.0

26.9

20.8

10.7

15.0

16.1

34.9

25.0

19.6

9.6

14.0

15.6

32.5

27.0

18.0

—

14.0

14.0

paratype*

31.4

22.0

—

9.4

12.9

14.0

* Measurements given by Morrison (1955: 160).

64

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[54: 2

larly those with fewer than 4.5 whorls. Aperture
nearly circular, slightly wider than high; width
of aperture 0.43-0.45 times major diameter.
Peristome continued across parietal margin by
a thick callus. Posterior corner of aperture with
a weak, impressed groove and advanced as a
small point. Aperture strongly oblique in lateral
profile and slightly sinuous. Interior white.

Operculum (PI. I, I). Nearly planular;
slightly depressed in the center and with a low
knob over the inner surface of the nucleus. Con-
sisting of about 9 closely coiled whorls. Outer
surface with a moderately thick spiral calcareous
layer. Chitinous basal plate thin and with
oblique weak lamella that are worn away at the
outer surface of the operculum. Spiral calcare-
ous lamellum highest along inner margin and
sloping outward.

Male (Text-fig. 8, C-D). The verge is similar
in location and structure to that of other mem-
bers of the genus. The distal end forms a large
funicular opening in which the seminal groove
terminates.

Female. None examined.

Type Locality. Ocozocoautla, Chiapas.
Holotype: USNM 618777. Paratype: USNM
618778.

Specimens Examined. Chiapas: 15.8 mi.

N. W. Ocozocoautla, 2700 ft. alt. (UF 20174.
3), (UF 19180. 2).

Anatomical Material. One male from
UF 20174.

Remarks. This species is closely related to
other Chiapas members of the genus Amphicy-
clotus s. s., as is indicated by the structure of
the verge, the vermiculate sculpture on the shell,
and the closely coiled multi-whorled operculum.
It differs from all other members of Amphicy-
clotus s. s., as well as the problematic genera
Barbacyclus and Megacyclotus by the presence
of a moderately heavy spiral calcareous deposit
on the outer surface of the operculum, much as
occurs in Neocyclotus. On the basis of this
character, megaplanus could be accorded sepa-
rate generic status from Amphicyclotus as has
frequently been done with other members of the
family by using such criteria. Because it is closely
related to other members of Amphicyclotus s. s.
by the structure of its verge, and since we know
nothing of its female reproductive system, I hesi-
tate to separate megaplanus from Amphicyclo-
tus s. s. A recent suggestion (Solem, 1956: 46)
that megaplanus may be subspecifically related
to A. texturatus (Sowerby) is without basis, and
is highly unlikely because of the opercular
differences.

Barbacyclus Bartsch and Morrison
Barbacyclus Bartsch and Morrison, 1942; Bull.
U. S. Nat. Mus., 181: 175. (Type species:
Cyclophorus underwoodi Da Costa, 1900).
Bartsch and Morrison separated Barbacyclus
from Amphicyclotus and allied genera by the
forward projection of its upper lip, its spiral
banding, its strong oblique thread-like sculp-
ture, and its operculum which bears fimbriations
along the outer edge of each turn. Solem ( 1956:
43) expressed doubt about the generic signifi-
cance of these characters. Material pertaining
to this genus is still rare in collections, and the
only information on its anatomy is provided in
the short description given below for B. princeps
(Pilsbry). The anatomical material that I have
examined is limited to a single incomplete male,
but indicates that Barbacyclus is distinct from
Amphicyclotus by the possession of a small
spoon-like penis at the tip of the verge. Because
of this anatomical distinction, I tentatively favor
the recognition of Barbacyclus as generically
distinct from Amphicyclotus, though the two
are close in their relationship.

Barbacyclus princeps (Pilsbry)

Aperostoma (Amphicyclotus) princeps Pilsbry,
1935; Proc. Acad. Nat. Sci. Phila., 87: 3; pi.
1, figs. 1, la, lb.

Barbacyclus princeps (Pilsbry), Bartsch and
Morrison, 1942; Bull. U. S. Nat. Mus., 181:
175-176; pi. 23, figs. 1-3.

Costa Rica (Limon Prov.): Moin Hill,
nr. Limon (UF 20143. 20), (UF 20144. 20),
(UF 20145. 3), (UF 20147. 2), (UF 20146. 1);
all lots collected by Colin Little.

The material is rather homogeneous in char-
acter, and its variation is not sufficient to include
other named forms. One single shell contained
a partially decomposed animal that was in suffi-
cient condition to provide the following notes on
its reproductive anatomy.

Male (Text-fig. 7. D-E). The verge is located
on the center of the nape beneath the mantle
collar, and is directed posteriorly when relaxed.
The verge is nearly uniform in diameter through-
out its length, and is terminated by a thin, fleshy,
spoon-like penis. An open seminal groove ex-
tends from the anterior end of the prostate
across the nape and along the ventral surface
of the verge to the penis. The seminal groove is
bounded on either side by large ridge-like folds
that continue to the tip of the verge.

Neocyclotus Fischer and Crosse, 1886
As used in this paper, Neocyclotus includes
as subgenera Neocyclotus s. s., Incidostoma

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

65

1969]

Bartsch and Morrison, 1942 (see Morrison,
1955: 157), and Cyclohidalgoa Bartsch, 1942.
This last group lies beyond the geographic limits
of this paper, and anatomical material pertain-
ing to it is not available.

Neocyclotus is a large genus distributed
through most of tropical South America, the
Lesser Antilles, and Central America north to
Veracruz, Mexico. The genus is represented in
Mexico and Central America by a few species
of two subgenera, Neocyclotus s. s. and Incido-
stoma. Our knowledge of the anatomy of the
genus consists of a description of the female
reproductive system of N. dysoni (Pfeiffer)
(Tielecke, 1940: 338-339), some brief observa-
tions on the external male reproductive struc-
tures of N. wetinori (Bartsch and Morrison),
N. grenadensis mcsweeni ( Bartsch ) , N . (I.)
giganteum (Reeve), and N. (C.) translucidum
bejumense (Baker) (Morrison, 1955: 156-157),
and the anatomical observations given below
representing the type of the genus (N. dysoni),
some closely related species, and a single species
of the subgenus Incidostoma.

Neocyclotus is characterized anatomically by
having an elongate dorso-ventrally compressed
verge that is terminated by a simple flagellum-
like penis lying along the ventral distal margin
and between two labiate folds of flesh (Text-
fig. 11, D-F). A seminal groove extends from
the anterior end of the prostate, across the nape,
and along the ventral side of the verge to the
tip of the penis. The seminal groove may be
open (Incidostoma) , or it may be secondarily
coalesced by a raphe to form an internal sperm
duct and a superficial seminal furrow overlying
the duct (Neocyclotus) . The prostate is simple
in structure, with a semicircular lumen resulting
from a partial involution on the ventral side.
The oviduct forms a sigmoid loop at the distal
end of the uterus. The distal segment of the
loop is enlarged into an albumen gland. The
seminal receptacle is large, globular, hollow, and
has a short stout duct that connects to the ovi-
duct. The genital duct enters the wall of the
uterus and about halfway above the vagina be-
comes enlarged and folded as part of the uterus
(Text-fig. 13). The uterine lumen is divided by
a complete involution of the ventral wall. This
forms two chambers that interconnect at the
distal end, so that a single long sigmoid passage
is formed from the common genital duct to the
vagina (Text-fig. 13, B) . The vagina is short and
is confined to the anterior end of the uterus.

I he two subgenera considered do not differ
significantly in the female reproductive system.
They are readily recognized by conchological
features. Incidostoma has a bicolor shell with

simple costutate sculpture, and a tightly coiled
operculum with 8 to 1 1 whorls. Neocyclotus
has a unicolor shell that generally has anas-
tomosing sculpture, and the operculum con-
tains about 5 to 6 rapidly expanding whorls.
These differences might be considered sufficient
basis for separating the two as genera, but the
close anatomical similarity between them and
the intermediate nature of some species over-
shadows their distinctiveness. Also we do not
know the variability of opercular and anatomical
characters among the South American species of
Incidostoma or Neocyclotus.

Neocyclotus s. I. is closely related to a large
assemblage of West Indian genera. These in-
clude Cyclopilsbrya Bartsch, 1942; Cycloba-
keria Bartsch, 1942; Cyclojamaicia Bartsch,
1942; Cyclochittya Morrison, 1955; Poteria
Gray, 1850; Plectocyclotus Kobelt and Moellen-
doriff, 1898; and probably Rugicyclotus Mor-
rison, 1955. These genera are closely allied by
the terminal structure of the verge (Morrison,
1955). All possess a verge similar to that found
in Neocyclotus, in contrast to all other neo-
tropical genera which have basically different
male reproductive structures. Morrison’s obser-
vations are not detailed enough to allow an
analysis of generic interrelationships, for he
only examined the external male genitalia. A
large closely related assemblage of genera such
as this might be considered worthy of subfa-
milial recognition, except that in this instance
the generic taxonomy is “over refined” and
exaggerates the true degree of differentiation.

Besides the species and subspecies listed
below, Neocyclotus includes several additional
Central American and Mexican forms (see
Bartsch and Morrison, 1942: 204-219, 233-
242. Solem, 1956: 53-54).

Subgenus Neocyclotus Fischer and Crosse, 1886
Neocyclotus Fischer and Crosse, 1886; Miss.

Sci. Mex., 2: 148. — Morrison, 1955; Jour.

Wash. Acad. Sci., 45: 156. (Type species:

Cyclostoma dysoni Pfeiffer, 1851).
Austrocyclotus Bartsch, 1942; Bull. U. S. Nat.

Mus., 181: 133. (Type species: Cyclostoma

stramineum Reeve, 1843).

Neocyclotus s. s. is a specialized subgenus
evolved from a more generalized South Ameri-
can lineage. This is suggested by both its anat-
omy and its geographic distribution. The co-
alesced seminal groove forming a sperm duct
in the male is derived from the more generalized
condition of an open groove such as occurs in
Incidostoma. The geographic distribution of
Neocyclotus s. s. in Central America and Mexico
indicates a group that relatively recently has

66

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[54: 2

immigrated northward from South America and
has not yet undergone much evolutionary di-
versity at the specific level. In contrast, several
very distinct species of Neocyclotus s. s. occur
in northern South America and the Lesser An-
tilles. The migration northward from South
America probably was initiated in the early
Pliocene when Central and South America
became connected. The distribution and differ-
entiation of N. dysoni in Mexico suggests an
even more recent immigration of the genus into
that region.

Neocyclotus dysoni ambiguum (Martens)

Cy dot its ( A perostoma ) dysoni ambiguum Mar-
tens, 1890; Biol. Cent. Amer.: 4.

Neocyclotus dysoni ambiguum (Martens), Ko-
belt and Mollendorff, 1897; Nachrb. Deutsch.
Malak. Ges., 29: 137. — Solem, 1956; Proc.
Acad. Nat. Sci. Phila., 108: 53.

Poteria (Neocyclotus) dysoni ambiguum (Mar-
tens), Baker, 1923; Occ. Pap. Mus. Zool.
Univ. Mich., (137): 34.

A perostoma (Neocyclotus) dysoni ambiguum
(Martens), Bartsch and Morrison, 1942;
Proc. U. S. Nat. Mus., 181:211; pi. 28; figs.
10-12.

Veracruz: Laguna Encontado, nr. San

Andres Tu.xtla (UF 19163, 56). Tabasco:
2.4 mi. E. Teapa (UF 20213. 1); 2.6 mi. E.
Teapa (UF 19167. 3); 4.0 mi. W. Teapa (UF
19166. 3). Chiapas: 8.0 mi. N. Tuxtla Gutie-
rrez, 3800' (UF 19297. 22); 8.6 mi. E. Chiapa
de Corzo, 3100' (UF 19164. 10); 14.9 mi. E.
Chiapa de Corzo, 4400' (UF 19165. 5).

Anatomical Specimens. Chiapas: 8.6 mi.
E. Chiapa de Corzo (4 females, 3 males).

Male. The prostate (Text-fig. 11, B-C) is
baso-columellar in position and is a simple
tapering clavate structure that is enlarged dis-
tally and pointed basally. Its surface is finely
furrowed due to underlying glandular lobes.
The prostatic lumen (Text-fig. 11, C) is a semi-
circular cavity that is lined on two sides by thick
glandular layers. The dorsal layer is derived
from a partial involution, but the interior is not
divided into two interconnected chambers, as in
Dicrista and Amphicyclotus. The verge (Text-
fig. 11, D-F) lies on the center of the nape and
is coiled and folded clockwise and posteriorly.
The verge is broadly expanded at the base and
gradually tapers distally. The tip of the verge
bears a cleft that is bordered on its two sides by
labiate folds. A slender terminal flagellum origi-
nates at the base of the cleft and along one side.
Distally it bears a shallow groove along its dor-
sal side into which the sperm duct terminates.
A strong fleshy fold extends across the nape

from near the end of the prostate to the base
of the verge, and continues along the ventral
side of the verge as a shallow seminal furrow.
The furrow is highly variable due to the state
of relaxation of the verge, and may appear as
a deep groove. The sperm duct (Text-fig. 11,
E-F) is an enclosed tube that extends from the
prostate to the tip of the flagellum at the distal
end of the verge. It lies within the nape fold
and beneath the seminal furrow. The sperm duct
is derived from a deep seminal groove, for it is
connected to the outer surface of the nape and
verge by a coalesced and keratinized raphe. The
overlying nape fold and seminal furrow have
been wrongly interpreted as a seminal groove by
other authors.

Female (Text-fig. 13, A). The uterus is
stocky, short and dorso-ventrally compressed
distally. The outer and distal margins have nu-
merous large lobes caused by the pattern of the
underlying glandular fold in the uterine wall.
The vaginal slit is short and is near the anterior
end of the uterus. The interior of the uterus is
divided into two chambers by a thick involution
that extends to the opposite wall (Text-fig. 13,
B-C). The chambers are interconnected distally.
The vaginal slit opens into the right chamber,
which serves as a functional vagina. The left
chamber has a U-shaped loop at its anterior
end, which is caused by the side of the uterus
being folded back upon itself. The genital duct
discharges into the uterine chamber at the end
of this folded loop. The oviduct forms an
elongate sigmoid loop along the distal end of
the uterus. The distal segment of the loop is
slightly enlarged and forms a lobate albumen
gland. The lower segment of the loop is tightly
attached by connective tissue to the ventral side
of the uterus. The seminal receptacle is large,
globular, hollow; is partially impressed in the
ventral side of the uterus; and is attached to the
oviduct by a short duct. The two ducts form a
genital duct that is imbedded in the uterine wall
and enters the uterus one-third of the distance
above the vagina.

Neocyclotus dysoni dysoni (Pfeiffer)

Cyclostoma dysoni Pfeiffer, 1851; Proc. Zool.
Soc. Lond., 19: 243. — Pfeiffer, 1852; in
Martini-Chemnitz, Conchylien Cabinet, 1,
sec. 19: 259; pi. 35, figs. 5-6.

Neocyclotus dysoni (Pfeiffer), Fischer and
Crosse, 1888; Miss. Sci. Mex. l’Amer. Cent.,
2, (7) : 164, in part.

Cyclotus (Aperostoma) dysoni (Pfeiffer), Mar-
tens, 1890; Biol. Cent. Amer.: 3.

Aperostoma (Neocyclotus) dysoni dysoni (Pfeif-
fer), Bartsch and Morrison, 1942; Proc. U. S.
Nat. Mus., 181: 207-208; pi. 28, figs. 28-30.

1969]

Land Snails of the Family Cyclophoridae
Thompson: Some Mexican and Central American

67

Text-fig. 1 1. Male reproductive structures of Neocyclotus. A. N. bisinuatus (Martens), prostate; Tapanti,
Costa Rica. B. N. d. ambiguum (Martens), prostate; 8.6 mi. e Chiapa de Corzo, Chiapas. C. Cross-
section through prostate of B at point indicated by arrow. D-F. N. d. ambiguum (Martens), dorsal view
of verge (D) and enlarged illustrations of dorsal (E) and ventral (F) views of the terminal portion of
the verge showing the relationships of the sperm duct to the seminal furrow and the penis. Scales equal
3 mm.

68

Zoologica: New York Zoological Society

[54: 2

Honduras (Comayagua Prov.): 4 Km.
S. S. W. (Comayagua, stream drift (UF 20165,

1 ); 15.1 mi. N. Comayagua, 4200' (UF 19162.
17).

Neocyclotus dysoni dveri (Bartsch & Morrison)
Aperostoma ( Neocyclotus ) dysoni dyeri Bartsch
and Morrison, 1942; Proc. U. S. Nat. Mus.,
181: 205; pi. 28, figs. 31-33. - Solem, 1956;
Proc. Acad. Nat. Sci. Phila., 108: 54. (Type
locality: La Ceiba, Honduras).

Honduras (Colon Prov.): Balfate (UF
20166. 5).

This is a giant subspecies confined to the
coastal region of northern Honduras and adja-
cent regions of Guatemala. Specimens from
Balfate, Honduras, have a distinct notch in the
basal lip, as in specimens discussed by Solem
( 1956:54) . In this respect they tend to approach
N. bisinuatus (von Martens) from Costa Rica,
but I have not examined sufficient material from
Nicaragua to demonstrate intergradation.

Neocyclotus dysoni nicaraguense

(Bartsch and Morrison)

Aperostoma ( Neocyclotus ) dysoni nicaraguense
Bartsch and Morrison, 1942; Proc. U. S. Nat.
Mus., 181: 214-215; pi. 29, figs. 16-18.
Costa Rica (Guanacaste Prov.): 3.8 mi.
S. Nicoya (UF 20162. 9); 2.2 mi. S.E. Nicoya,
500' (UF 201 63. 50 ) ; 1.2 miles east of Caimital
(UF 20164. 26).

This subspecies was described from the dry
Pacific coastal region of Polvon, Nicaragua. Its
occurrence in Costa Rica is an extension of its
known range southward to the Nicoya Peninsula.

Neocyclotus simplicostus new species
Diagnosis. A species of the subgenus Neo-
cyclotus distinguished from all others by having
simple costulate sculpture. It is closely related
to TV. dysoni (Pfeiffer) by its opercular struc-
ture and its anatomy, but is distinguished by its
smaller size as well as its sculptural characters.

Description (PI. II, J-L). Shell small, light
brown, becoming slightly lighter on base and
in umbilicus. Dull satiny. Helicoid, height 0.74-
0.83 times major diameter. Spire elevated, coni-
cal; nearly straight sided, being very slightly
convex. Whorls rapidly increasing in size; minor
diameter 0.69-0.84 times major diameter. Um-
bilicus moderately sized, but highly variable,
about 1/5-1/10 of major diameter. 4. 0-4.4
whorls in mature shells (4.3 in holotype). Su-
ture strongly impressed. Whorls nearly uni-
formly rounded; slightly extended peripherally;
weakly shouldered. Last whorl usually not de-
scending near the aperture. Embryonic whorls
1.7-1. 9; smooth. Following whorl or so with
irregular weak axial striations which become
more intense and transform into ribs on last
quarter of penultimate whorl. Body whorl with
strong parallel, slightly oblique axial ribs that
continue only slightly diminished across base and
into umbilicus. In contrast with other species of
Neocyclotus the ribs do not anastomose. Aper-
ture large, broadly ovate, slightly indented along
parietal margin; hyaline white internally; slightly
oblique in lateral profile. Aperture width 0.49-
0.54 times major diameter. Peristome simple,
continued across parietal margin by a callus.

Operculum (PI. I, J). Solid and calcareous.
Consisting of about six whorls that rapidly in-
crease in size. Nucleus sunken. Each succeeding
whorl lying on a slightly higher plane than pre-
vious whorls. Inner edge of whorls forming a
slightly raised spiral chord. Chitinous basal
plate forming a small knob under nucleus; not
extending through outer calcareous surface.

Male (Text-fig. 12, E). The verge is similar
to that of N. d. ambiguum, except smaller. It
ends in a slender flagellar extension that lies
between two terminal labia. The sperm duct is
enclosed within the verge, but is connected to
the seminal furrow by a coalesced raphe. The
sperm duct continues internally from the pros-
tate to the tip of the flagellum. There is a low

Measurements

in mm of the ten largest specimens

from the type

series of N .

simplicostus are:

Maj. Diam.

Min. Diam.

Height

Umbil.

Aper. H.

Aper. W.

14.8

11.3

12.2

1.4

8.3

8.0

holotype

15.4

12.9

12.2

2.3

8.2

7.6

paratype

15.4

11.9

12.2

2.0

8.1

7.6

paratype

14.9

11.3

11.4

2.6

8.1

7.3

paratype

14.0

10.5

10.6

2.3

7.8

7.1

paratype

14.1

10.2

10.4

2.7

7.7

7.2

paratype

14.7

10.9

11.3

1.7

7.7

7.3

paratype

14.5

10.0

11.5

1.7

7.6

7.1

paratype

13.1

10.0

10.1

1.6

7.2

6.4

paratype

13.7

10.0

10.4

2.0

7.3

7.1

paratype

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

69

ridge on the nape overlying the sperm duct and
extending from the prostate to the base of the
verge, where it continues as the seminal furrow.

Female (Text-fig. 13, D). The uterus and
associated organs are similar to those of N. d.
atnbiguum though smaller. The seminal recep-
tacle is more elongate, and the lower part of the
genital duct converges into the uterus more
rapidly.

Type Locality. A ravine 4.2 miles northwest
of Escuintla, Chiapas; 300 feet altitude. Holo-
type: UF 20167; collected 24 July, 1966 by
Fred G. Thompson. Paratypes: UF 20168
(30), UMMZ 216559 (5); same data as holo-
type. The type series was collected in leaf mulch
and debris in a second growth quasi-rain forest,
along the side of a ravine. The soil consisted of
lateritic clay.

Other Specimens Examined. UF 20171 (19
spec, in alcohol from type locality). Chiapas:
21.3 mi. N. W. Huixtla, 300' (UF 20169. 33);
32.5 mi. N. W. Huixtla, 200' (UF 20170. 3),
(UF 20172; 2 spec, in alcohol).

Geographic Variation. This species is
known only from the vicinity of Escuintla,
Chiapas. It shows considerable variation be-
tween the three known populations. Specimens
from 21.3 mi. N. W. Huixtla differ from the
typical form in that the axial ribs on the base are
weaker, and form sharp threads in the umbilicus.
The specimens from 32.5 mi. N. W. Huixtla are
considerably larger than those of other popu-
lations, attaining a major diameter of 19.5-21.1
mm, but are typical in proportions. They also
differ in that they have stronger ribs on the
base and in the umbilicus. In other aspects of
the sculpture they are like the typical form.

Text-fig. 12. Male reproductive organs of three species of Neocyclotus. A. N. bisinuatus (Martens),
dorsal view of verge; Tapanti, Costa Rica. B. N. bisinuatus (Martens), enlargement of distal end of verge
from ventral view. C-D. N. ( Incidostoma ) impressus new species, dorsal and ventral views of verge;
topotype. E. N. simplicostus new species, ventral view of verge; topotype. Scales equal 5 mm; scale on
left for A, C, D; scale on right for E only.

70

[54: 2

Zoologica: New York Zoological Society

Text-fig. 13. Female reproductive systems of two species of Neocyclotus. A. N. d. ambiguum (Martens);
8.6 mi. e. Chiapa de Corzo, Chiapas. B. Diagramatic longitudinal section through uterus of A showing
course of uterine lumen. C. Cross-section of uterus of A at point indicated by arrow. D. N. simplicostus
new species, topotype. Scales equal 5 mm.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

71

Remarks. N. simplicostus differs from all
other species of the subgenus by its simple, uni-
form axial riblets that do not anastomose. It is
also distinguished from other species by its
smaller size. The distinction of sculpture is more
than can be accounted for by assuming that it is
only a local variation of the widely distributed
N. dysoni. A form of the latter species was col-
lected at 14.6 mi. N. N. E. Huixtla, 2100' (UF
20160). It is typical in its sculpturing and shows
no tendency to converge with the characters of
N. simplicostus.

Neocyclotus bisinuatus (Martens)
Cyclotus bisinuatus Martens, 1864; Malak-Blat-
ter; 11: 1 13; pi. 3; figs. 1, 2.

Cyclotus (Aperostoma) bisinuatus (Martens),
Martens, 1890; Biol. Cent. Amer.: 3.
Neocyclotus (Neocyclotus) bisinuatus (Mar-
tens), Kobelt and Mollendorff, 1897; Nachrb.
Deutsch. Malak. Gesell., 29: 137.
Aperostoma (Aperostoma) bisinuatus (Mar-
tens), Bartsch and Morrison, 1942; Proc.
U. S. Nat. Mus., 181: 235; pi. 33, figs. 5-6.

Costa Rica (Cartago Prov. ): Tapanti,
4300' (UF 20159. 13), (UF 20156. 18).
(Puntarenas Prov.): 5 mi. E. Villa Neily
(UF 20157. 1); Inter-American Agricultural
Institute, Turrialba, 2000' (UF 20158. 1 ). Ana-
tomical material was examined from each lo-
cality.

This species is widely distributed in Costa
Rica, and has been recorded from Guatemala
(Martens, 1890: 3) . Its relationship to N. dysoni
(Pfr.) is very close, but it is uncertain whether
the two species are conspecific. Bartsch and
Morrison (1942: 235) placed bisinuatus in
Aperostoma (Incidostoma — see Morrison,
1955: 157), because it has a bicolor base as do
other species of that subgenus. Unlike other
species of Incidostoma , and like most species of
Neocyclotus s.s., bisinuatus has anastomosing
sculpture on the lower whorls. Bartsch and Mor-
rison (1942: 213-214) described N. dysoni
valerioi from Cervantes, Costa Rica, character-
ized by having the vermiculated sculpture of N.
dysoni and by having a bicolor base as occurs in
N. bisinuatus. If valerioi is a subspecies of N.
dysoni, then the only distinction that remains
between dysoni and bisinuatus is the notches in
the peristome for which bisinuatus was named.
All of the material that I have identified from
Costa Rica as bisinuatus has the peristomal
notches, though to varying degrees due to onto-
genetic development of this character. None of
the material from Costa Rica that I have identi-
fied as N. d. nicaragueuse shows any indication
of such notches. However, some populations of

N . d. ambiguum, N. d. cooki, N. d. dyeri, and
an undetermined subspecies of N. dysoni from
eastern Nicaragua show a tendency for a single
notch to develop in the lower peristome. On the
basis of its. sculpture, opercular structure, and
reproductive anatomy, N. bisinuatus is more
closely related to N. dysoni (Pfeiffer) than it is
to the bicolor species of Incidostoma. Whether
N. dysoni actually integrates with N. bisinuatus
in eastern Nicaragua and Costa Rica remains to
be determined. It seems unlikely because of the
differences in the verges.

Operculum (PI. I, K). The operculum is
typical in structure for the subgenus Neocyclo-
tus. In large specimens it consists of 5 to 6 rap-
idly expanding whorls that overlap along the
inner margins, so that a spiral ridge that gently
slopes on the outside is formed. The calcareous
outer lamella bears numerous moderately strong
oblique striations. The inner surface has a raised
knob over the nucleus.

Male. (Text-fig. 12, A-B). The prostate lies
along the dextroventral margin of the coelom,
and is tapered anteriorly. The sperm duct forms
an enlarged loop prior to where it enters the
prostate. The verge is relatively long and slender,
with a broadly expanded base and an enlarged
funicular tip. Two lateral flaps lie along the
posterior (ventral) side of the verge about half-
way from the base. A slender flagellum extends
beyond the funicular end of the verge. A seminal
groove extends from the anterior end of the pros-
tate, across the nape in a broad curve, and along
the posterior (ventral) side of the verge to the
tip of the terminal flagellum. The groove con-
nects an enlarged underlying duct with the out-
side surface, and is not coalesced closed, as in
N. dysoni ambiguum and N. simplicostus.
Throughout most of its course, the groove and
underlying duct lie within a raised seminal
ridge. The verge is located on the center of the
nape and is directed posteriorly beneath the
mantle when relaxed.

Female (Text-fig. 14, A). The uterus and
associated structures are similar to those of N.
dysoni, though more simplified in certain as-
pects. The oviduct forms a sigmoid loop at the
distal end of the uterus. The albumen gland con-
sists of a weakly enlarged segment in the sig-
moid loop. The seminal receptacle is simple,
globular, and hollow, and is located on a short
stout duct that enters the common genital duct
which is embedded in the wall of the uterus. This
duct enlarges within the uterine wall, and re-
verses its direction to pass posteriorly as it en-
ters and transforms into a uterine chamber, as
occurs in D. dysoni. A major point of distinc-
tion between the two species is that the lower

72

Zoologica: New York Zoological Society

[54: 2

Text-fig. 14. Female reproductive systems of Neocyclotus. A. N. bisinuatus (Martens); Tapanti, Costa
Rica. B. N. bisinuatus (Martens), enlarged view of lower part of uterus showing transition of genital
duct into uterus. C. N. ( Incidostoma ) impressus new species, topotype. D. N. (/.) impressus; enlarged
view of lower part of uterus showing coarse of genital duct into uterus. Scales equal 5 mm.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

73

segment of the common genital duct is not as
strongly convoluted as occurs in N. dysoni.
Other aspects of the utera are very similar.

Neocyclotus capscelius new species

Diagnosis. A species tentatively assigned to
the subgenus Neocyclotus. It differs from all
other species by its fine axial thread-striations,
and by its complex operculum which bears a
raised spiral calcareous lamella reinforced later-
ally by thin oblique lamellar-like buttresses.

Shell (PI. V, E-H). Medium sized, thin and
relatively fragile. Uniform satiny brown with
occasional irregular dark streaks occurring along
growth threads. Very depressed-helicoid; height
0.62-0.68 times major diameter. Spire low,
slightly convex in outline. Umbilicus moderately
large, about 0.23-0.25 times major diameter.
Whorls, 5.0 in holotypes (which is largest com-
plete specimen). Whorls of moderate caliber,
slowly increasing in size; minor diameter 0.75
times major diameter. Suture moderately im-
pressed. Last whorl not descending near aper-
ture. Embryonic whorls protruding, pitted, and
eroded so that exact number is not determined.
First whorl 0.9 mm in diameter perpendicular
to initial suture. Sculpture on lower whorls con-
sisting of fine, irregular thread-striations that
parallel lines of growth. Sculpture continuing
across base only slightly diminished. Aperture
circular, oblique in lateral profile; width of aper-
ture 0.45-0.47 times major diameter; interior
with a thin livid gloss. Aperture slightly indented
by preceding whorl; slightly auriculate due to
forward extension of posterior corner. Peri-
stome simple, sharp, continued across parietal
margin by a thin callus.

Operculum (PI. V, H). Consisting of about
eight closely coiled whorls. Along its inner mar-
gin calcareous lamella abruptly rising above pre-
ceding whorls forming a low spiral wall. Nu-
merous thin lamella-like buttresses extend
obliquely outward from the spiral ridge. Nuclear
region depressed.

Type Locality. A wooded ravine on Cerro
de la Muerte, 10.5 kilometers north of San
Isidro El General, San Jose Prov., Costa Rica,
5200 feet altitude. Holotype: UF 20148;
collected 14 July, 1963 by Richard C. Casebeer.

Paratypes: UF 20149 (4); 14.2 km. north
of San Isidro El General, 5600 feet.; collected
5 August, 1963 by Fred G. Thompson. Speci-
mens were found at both localities among de-
bris and mosses in densely wooded ravines in
the transitional zone between rain forest and
cloud forests.

Remarks. In some aspects N. capscelius has
a youthful appearance, though the holotype
probably represents the definitive form of its
species. The entity is characterized by its fine
thread-striae, low spire, and peculiar operculum
bearing a raised calcareous lamella reinforced
on the outside by oblique thin lamellar-like but-
tresses. Its phylogenetic relationships are diffi-
cult to determine. By the combination of its
characters it has no close relationship to any
known species. On the basis of shell features it
would be placed in the genus Dicrista. Its oper-
culum, which I consider more significant, sug-
gests a relationship with Neocyclotus. Within
Neocyclotus it cannot be clearly assigned to any
subgenus, for its characters can be derived from
any of three subgenera, Neocyclotus s. s., Inci-
dostoma and Cycloliidalgoa. The only subgenus
within this assemblage that has a tendency for
the operculum to vary in the direction exhibited
by capscelius is Neocyclotus. In contrast with
other species of Neocyclotus s. s., capscelius has
a closely coiled operculum as occurs in Central
American species of Incidostoma. However, all
Central American species of Incidostoma are
bicolored and have heavier sculpture as is de-
scribed below for N. (/.) impressus n. sp. The
shell sculpture of capscelius tends to be similar
to that of Cycloliidalgoa, but its operculum dif-
fers from that subgenus as it does from Neocy-
clotus. Because of its distinctive features cap-
scelius could be placed in a separate subgenus,
but this should not be done until its anatomy
has been examined so that its relationships can
be determined with certainty.

N. capscelius is named for Richard C. Case-
beer, who brought this interesting species to my
attention.

Subgenus Incidostoma Bartsch and Morrison
Incidostoma Bartsch and Morrison, 1942; Bull.

U. S. Nat. Mus., 181: 187. - Morrison, 1955;

Measurements in mm of the three largest specimens of N. capscelius are:

Maj. Diam.

Min. Diam.

Height

Umbil.

A per. H.

A per. W.

25.6

19.1

15.9

6.3

11.8

11.5

holotype

25.5

19.0

—

6.2

11.6

12.0

paratype

21.4

16.1

14.6

5.0

10.0

10.0

paratype

74

Zoological New York Zoological Society

[54: 2

Jour. Wash. Acad. Sci., 45: 157. (Type spe-
cies: Incidostoma malleatum Bartsch and
Morrison, 1942) .

Pseudaperostoma Baker, 1943; Naut., 56:135.
(Type species: Cyclostoma inca (Orbigny,
1835).

This subgenus contains two distinct sections
that perhaps should be recognized as subgenera.
The typical section possesses a strong siphonal
notch in the aperture and occurs in Colombia,
Ecuador, Peru, and perhaps Brazil. The other
section ( Pseudaperostoma ) lacks a notch, is
more widely distributed in South America, and
occurs as far north as Costa Rica. Morrison
(1955: 157) synonymized the two because a
series of one species ( Incidostoma incomptum)
includes individuals that bridge this distinction
through ontogenetic development. If one fails
to recognize generic characters that develop only
after maturity, many genera of mollusks would
have to be relegated to synonymy. Such a cri-
terion is highly undesirable, for it would result
in a few “megagenera” in those instances where
the generic characters are not apparent until the
shell has completely developed or the animal has
undergone sexual maturity. I follow Morrison’s
usage of Incidostoma rather than propose an-
other name change, only because so many South
American cyclophorids are poorly founded and
are anatomically unknown.

The Central American Incidostoma are di-
vided into two species groups (Bartsch and Mor-
rison, 1942: 233-250). The carmioli group is
confined to Costa Rica, has fine axial ribs in the
umbilicus, and has one or two notches in the
peristome. The giganteum group occurs in Pan-
ama, Colombia, and Ecuador; has heavy axial
ribs in the umbilicus; and has a slight angle in
the posterior corner of the aperture. Several
species in both groups are founded on scant
material. A large number are not known from a
specific locality, but only a country. The species
treated below belong to the carmioli group and
are from Costa Rica. The material, though lim-
ited, adds substantially to our knowledge of this
group.

Neocyclotus (Incidostoma) carmioli

(Bartsch and Morrison)

Aperostoma (Aperostoma) carmioli Bartsch and

Morrison, 1942; Proc. U. S. Nat. Mus., 181:

233; pi. 32, figs. 19-21.

Costa Rica (Cartago Prov.) : Rio Chitaria,
2 km. N. E. Jabillas, 3000'; collected by Andrew
Starrett, 3 August, 1957 (UMMZ 216557. 2).

Previously this species was not known from
any specific locality, and was represented only
by the holotype (USNM 25034) and a single
immature paratype ( USNM 405227) . The speci-
mens collected by Starrett are similar to the
holotype in all respects, except that they are a
bit larger and have a proportionally higher
aperture.

Neocyclotus (Incidostoma) irregulare (Pfeiffer)

Cyclostoma (Cyclotus) irregulare Pfeiffer, 1855;

Proc. Zool. Soc. Lond., 23: 1 17.

Cyclotus irregulare (Pfeiffer), Pfeiffer, 1858;

Monogr. Pneumon. Viv., 2: 15. — Reeve,

1864; Conchol. Iconica, 14: pi. 4, fig. 18.
Aperstoma (Aperstoma) irregulare (Pfeiffer),

Bartsch and Morrison, 1942; Bull. U. S. Nat.

Mus., 181: 236; pi. 33, fig. 4.

Costa Rica (Limon Prov.): Pandora (UF
20150. 1).

This species previously was known from
“Costa Rica,” but without specific locality. The
single specimen examined (PI. VII, D-F) closely
fits Pfeiffer’s description and Reeve’s figure, dif-
fering only in minor details. Pfeiffer’s measure-
ments are in error, in part, for they imply a very
depressed shell. He gives the dimensions as:
major diameter 37 mm; minor diameter 30 mm;
height 19 mm. Reeve’s figure of the type shows
a specimen that is about 26 mm in height. Meas-
urements in mm for the specimen from Pandora
are: major diameter, 31.1; minor diameter, 23.9;
height, 25.2; aperture height, 15.7; aperture
width, 14.7; umbilicus, 5.2; 5.0 whorls. The cir-
cumbilical angle is not as strongly developed as
in Pfeiffer’s specimen, for it is rather weakly
indicated.

The operculum consists of about 1 1 closely
coiled whorls (PI. VII, D). The inner margin of
the calcareous lamella is raised and overhangs
the preceding whorl. The outer slope is rather
coarsely and irregularly sculptured with oblique
striations.

Measurements in mm for specimens of N. (I.) carmioli are:

Maj. Diam.

Min. Diam.

Height

Umbil.

A per. H.

A per. W .

Whorls

44.0

30.5

30.0

8.5

21.4

20.3

5.0

42.1

30.5

27.7

7.8

21.7

20.0

5.0

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

75

Neocyclotus (Incidostoma) impressus

new species

Diagnosis. A member of the subgenus Inci-
dostoma belonging to the carmioli species group,
characterized by small size, wide umbilicus,
single notch in the lower peristome, and an im-
pressed dent on the inside of the aperture lateral
to the notch. It is similar to N. (/.) pit fieri
(Martens), but differs by being more elevated
in spire, and smaller. It is not known whether
pittieri has the impressed dent that characterizes
impressus.

Shell (PI. VII, A-C, G). Medium sized.
Solid, but of variable thickness. Bicolor. The
dorsal surface consists of a light tan zone that
may have a reddish tinge in its middle, and is
bound at the periphery by a reddish brown band.
The band blends into the lighter colored base,
which is similar in hue to the dorsal surface. The
intensity of the color pattern is highly variable,
and in most specimens tends to be lighter than
in the holotype. Shell depressed helicoid, height
0.62-0.73 times major diameter. Spire low,
weakly convex in outline. Umbilicus moderately
large, 0.18-0.25 times major diameter. Whorls
4. 5-4. 8 in mature specimens (4.7 in holotype),
of moderate caliber; minor diameter 0.71-0.75
times major diameter. Body whorl descending
slightly near aperture. Suture moderately im-
pressed. Embryonic whorls 1.7; moderately pro-
truding; smooth. Following whorls crossed by
slightly oblique parallel axial threads that trans-
form into riblets on lower whorls. Riblets on
last whorl uniform, diminishing slightly on ven-
tral surface, and coalescing in umbilicus to form
sharp thread-riblets. Aperture circular, becoming
auriculate at posterior corner, which is advanced
along suture; 0.44-0.50 times major diameter.
Aperture weakly indented by preceding whorl;
livid white internally; lying at an oblique angle.
Peristome simple, sharp, continued across parie-
tal margin by a moderately thick callus. Basal
lip with a small notch. Midway between the
notch and the periphery, the interior of the peri-
stome bears a small impressed dent that occupies
the same position as the outer peristomal notch
in N. (/.) exiguum (Bartsch and Morrison).

Operculum (PI. I, L). Consisting of about
eight closely coiled whorls that uniformly in-
crease in size. Inner margin of calcareous
lamella abruptly raised, and gradually sloping
outward so that a spiral ridge is formed. Outer
slope irregularly sculptured with oblique stria-
tions. Nuclear region dished out. Inner surface
smooth; with a low conical mound over nucleus.

The anatomical material is not in optimal
condition for dissection, but is sufficient to reveal
essential aspects of the male and female repro-
ductive system. These systems appear as though
the individuals are not in breeding condition.
The verge and the structures associated with the
genital ducts appear to be normal in develop-
ment, but the prostate and uterus are slightly
atrophied. However, these organs are well
enough developed to indicate the species phylo-
genetic alliances.

Male (Text-fig. 12, C-D). The verge lies on
the center of the nape beneath the mantle collar,
and is directed posteriorly when retracted. A
deep seminal groove extends from the anterior
end of the prostate, across the nape, and the
length of the verge along its posterior (ventral)
surface. The end of the verge bears two folds
which form a funicular tip. A slender terminal
flagellum lies at the base of these folds. The
seminal groove extends to the tip of the flagel-
lum.

Female (Text-fig. 14, C-D). The female
reproductive system is similar to that of N.
bisinuatus (Martens) but is more simplified. The
oviduct forms a stout sigmoid loop. An albumen
gland is formed at the distal end of the loop.
The seminal receptacle is enlarged, sacculate,
and has a short thick duct that connects it to the
common genital duct. The latter is imbedded in
the wall of the uterus, forms a loop at about 1/5
of the distance above the vagina, and transforms
into a segment of the uterus with poorly differ-
entiated folds. The internal course of the uterus
is similar to that of N. dysoni.

Type Locality. Along road immediately
east of Nueva Castle, Limon Prov., Costa Rica.
Holotype: UF 20151; collected 30 August,
1967 by Colin Little. Paratypes: UF 20152

Measurements in mm of five specimens of N. (I.) impressus from the type series

are:

Maj. Diam.

Min. Diam.

Height

Umbil.

Aper. H.

Aper. W.

27.3

20.2

19.7

5.0

13.0

13.1

holotype

28.3

20.6

17.6

7.0

12.8

13.0

paratype

25.9

19.5

17.2

6.3

11.8

11.5

paratype

22.6

16.2

15.8

4.3

10.5

11.0

paratype

21.1

15.1

13.8

4.2

10.0

10.1

paratype

76

Zoologica: New York Zoological Society

[54: 2

(57), UMMZ 216560 (5); same data as the
holotype. The specimens were collected in
mulch from between the buttress roots of a large
Ficus tree.

Other Specimen Examined. Costa Rica
(Limon Prov.) : Pandora (UF 20153. 2).

Remarks. This species is highly variable in
appearance and proportions. The color is vari-
able to the extent that in some specimens the
peripheral dark zone is almost indistinguishable.
The apertural characters that distinguish it from
other known species are developed only after
maturity. Thirteen specimens in the type series
have matured sufficiently to show the notch and
the internal impressed dent in the lower lip. The
shell under the dent is thin and fragile, and it
may break away so that upon superficial exam-
ination a second notch may appear to be present.

This species is similar to N. (/.) exiguum
(Bartsch and Morrison) in size and appearance.
It is distinguished from the latter species by hav-
ing a wider umbilicus and a single notch in the
peristome, as opposed to having two well devel-
oped notches. I am uncertain about its relation-
ship to N. (/.) pittieri (Martens). The last
species was described as a variety of N. (/.)
irregulare (Pfeiffer). It was only briefly con-
trasted with irregulare and has not been figured.
N. (/.) pittieri is more depressed than is itn-
pressus, and it is larger in size. Martens (1900:
597) states that the type is 29 mm in diameter,
16.5 mm in height and has an aperture 10 mm
high. It was described from Salinas Bay, north-
western Costa Rica. Whether or not impressus
and pittieri are conspecific has yet to be demon-
strated. Their relationship is close.

References

Angas, G. F.

1879. On the terrestrial mollusca collected in
Costa Rica by the late Dr. W. M. Gabb,
with descriptions of new species. Proc.
Zool. Soc. Lond., 1879: 475-486; pi. 40.

Bartsch, P.

1942. The cyclophorid mollusks of the West
Indies, exclusive of Cuba. Bull. U. S. Nat.
Mus., 181: 43-143; pis. 9-18.

Bartsch, P., and J. P. E. Morrison

1942. The cyclophorid mollusks of the mainland
of America. Bull. U. S. Nat. Mus., 181:
142-278; pis. 19-42.

Clench, Wm. J.

1949. Cyclophoridae and Pupinidae of Caroline,
Fijian and Samoan Islands. Bull. Bernice
P. Bishop Museum, (196): 1-52.

Fischer, P., and H. Crosse

1870-1902. Mission scientifique au Mexique et
dans l’Amerique Centrale. Etudes sur les
mollusques terrestres et fluviatiles de
Mexique et du Guatemala. 2 volumes.

Kobelt, W.

1902. Cyclophoridae. Das Tierreich, 16: i-xxxix,
1-662.

Martens, E. von

1890-1901. Biologia Centrali-Americana. Mol-
lusca. i-xxviii, 1-702; pis. 1-44.

Morrison, J. P. E.

1955. Notes on American cyclophorid land
snails, with two new names, eight new
species, three new genera and the Family
Amphicyclotidae separated on animal
characters. lour. Wash. Acad. Sci., 45:
149-162.

Pfeiffer, L.

1851. Descriptions of forty-three new species of
Cyclostomacea, from the collection of
Hugh Cuming, Esq. Proc. Zool. Soc.
Lond., 1851: 242-251.

1855. Description of thirty-eight new species of
land shells, from the collection of Hugh
Cuming, Esq. Proc. Zool. Soc. Lond., 23:
111-119.

1865. Monographia Pneumonopomorum Viven-
tium, III: 1-284.

Solem, A.

1956. The helicoid cyclophorid mollusks of
Mexico. Proc. Acad. Nat. Sci. Phila., 108:
41-59; pis. 5-6.

Thiele, J.

1929. Hundbuch Systematischen Weichtier-
kunde, 1 (1): 1-376.

Thompson, F. G.

1963a. Systematic notes on the land snails of the
genus Tomocyclus (Cyclophoridae). Bre-
viora, (181): 1-11.

1963b. New land snails from El Salvador. Proc.
Biol. Soc. Wash., 79: 19-32.

1967. A new cyclophorid land snail from the
West Indies (Prosobranchia), and the dis-
cussion of a new subfamily. Proc. Biol.
Soc. Wash., 80: 13-18.

1968. Ceochasma, A remarkable new land snail
from Colima, Mexico. (Gastropoda, Pro-
sobranchia, Helicinidae). Proc. Biol. Soc.
Wash., 81: 45-52; figs. 1-21.

Tielecke, H.

1940. Anatomie, Phylogenie and Tiergeographie
der Cyclophoriden. Archiv fur Naturge-
schichte, N. F„ 9: 311-359.

Torre, C. de la, and P. Bartsch

1942. The cyclophorid mollusks of Cuba. Bull.
U. S. Nat. Mus., 181: 3-42; pis. 1-8.

1969]

Thompson: Some Mexican and Central American
Land Snails of the Family Cyclophoridae

77

EXPLANATION OF THE PLATES

Plate I

Opercula of Neocyclotinae.

A. Xenocyclus patulus new species, holotype.

B. Dicrista cooperi (Tryon), (UF 20190).

C. Dicrista damianensis (Solem), holotype.

D. Dicrista liobasis new species, holotype.

E. Dicrista flavescens new species, holotype.

F. Dicrista indentata new species, holotype.

G. Dicrista petersi (Solem), holotype.

H. Dicrista rugosa new species, holotype.

I. Amphicyclotus megaplanus Morrison, (UF

20147).

I. Neocyclotus simplicostus new species, holo-
type.

K. Neocyclotus bisinuatus (Martens), (UF

20156).

L. Neocyclotus (Incidostoma) impressus new spe-

cies, paratype.

Plate II

A-C. Dicrista cooperi (Tryon), (UF 20190).

D-F. Dicrista indentatus new species, holotype.
G-I. Dicrista flavescens new species, holotype.
J-L. Neocyclotus simplicostus new species, holo-
type.

Plate III

A-C. Dicrista liobasis new species, holotype.
D-F. Dicrista damianensis (Solem), holotype.

Plate IV

A-D. Dicrista petersi (Solem), holotype.
E-G. Dicrista rugosa new species, holotype.

Plate V

A-D. Xenocyclus patulus new species, holotype.
E-H. Neocyclotus capscelius new species, holo-
type.

Plate VI

A-C. Amphicyclotus texturatus spiralis new sub-
species, holotype.

D-F. Amphicyclotus paulsonorum new species,
holotype.

Plate VII

A-C. Neocyclotus (Incidostoma) impressus new
species, holotype.

D-F. Neocyclotus ( Incidostoma ) irregulare
(Pfeiffer), (UF 20150).

G. Neocyclotus (Incidostoma) impressus new

species, paratype.

THOMPSON

PLATE I

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORI DAE

THOMPSON

PLATE I!

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORI DAE

THOMPSON

PLATE II!

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORIDAE

THOMPSON

PLATE IV

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORIDAE

THOMPSON

PLATE V

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORI DAE

THOMPSON

PLATE VI

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORI DAE

>'V

THOMPSON

PLATE VII

SOME MEXICAN AND CENTRAL AMERICAN
LAND SNAILS OF THE FAMILY CYCLOPHORIDAE

5

The Underwater Song of Erignathus (Bearded Seal)

Carleton Ray,1 William A. Watkins,2
and John J. Burns3

(Plates I-III; Text-figure 1; Phonograph Disk)

Vocalization by mature males during breeding season. The call consists of a long oscil-
lating frequency-modulated warble that may be more than a minute in duration, followed
by a short unmodulated low-frequency moan. It typically starts at about 2000 cps with
many frequency variations and ends as low as 200 cps. This call has been identified with
the species by our own observations and those of others. Examination of seals heard
calling and which were killed revealed them to be males in breeding condition. Thus, this
“song” is apparently used solely by mature males in spring courtship season. It is suggested
that its purpose is a proclamation of territory or of breeding condition or both.

Introduction

Erignathus harbatus (Erxleben, 1777), the
bearded seal, produces a long combina-
tion of complicated underwater sounds
during the spring courtship season. This we have
termed the “song” because of its complex musi-
cal quality and apparent behavioral significance.
The characteristic frequency-modulated warble
and low moan, though produced entirely under-
water, may occasionally be heard in air, radiat-
ing through the water surface or ice-cover or
through the hull of the boat.

These musical underwater sounds have been
identified with the bearded seal by the Eskimos
who habitually hunt the species as a major
source of food and skins (Burns, 1967). The
association of singing sounds with the seals is
reflected in the names used for these animals by
the Alaskan Eskimos; when the seals are sing-
ing, the term that is used (“aveloouk” — Upik
dialect; “ayuktuk” — Inupik dialect) is trans-

1 Department of Pathobiology, School of Hygiene and
Public Health, The Johns Hopkins University, Balti-
more, Maryland 21205.

2 Woods Hole Oceanographic Institution, Woods
Hole, Massachusetts 02543 (Contribution No. 2028
from WHOI).

s Division of Game, Alaska Department of Fish and
Game, P.O. Box 862, Nome, Alaska 99762.

lated as “the one that sings” or “the singer.” The
reference is to the bearded seal (in-air known as
“mukluk” or “oogruk,” respectively).

The song of Erignathus was described by
Peter Freuchen (1921-24: pp. 224-225) as a
“shrill, siren-like note which is made in the
water and becomes deeper and deeper till it ends
in a long-drawn-out sigh.” The sigh he described
as a “strange, dull, deep-toned sound,” remark-
ing that some “sighs” were accompanied by
bubbles which he thought indicated that the seal
would shortly surface. The description fits the
underwater sound very well and has been quoted
by other more recent authors. Poulter (1966)
has described the underwater signals of Erigna-
thus, but the spectrographic analyses he pre-
sents are hard to compare with ours since no
scale is indicated and a non-standard logarithmic
frequency portrayal is used. It seems likely that
these are sounds of Erignathus, but we do not
find either the high (6 kcps) frequency starts
or the consistently distinct pulses he describes.

Over the past 10 years two of us (C. R. and
J. B.) have observed Erignathus in the Bering
Sea. These observations have included a num-
ber of instances when the “singing” could defi-
nitely be attributed to a seal in the water. Usually
only a part of the song was heard in-air as a
seal was closely approached, but through a series

79

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Zoologica: New York Zoological Society

[54: 2

of such exposures a general impression of the
song has been obtained. These impressions have
been confirmed by underwater recordings made
from shore, from pack ice, and from small boats
on 7, 8, 9, 10, 14, 20, and 21 May 1966 near
Gambell, St. Lawrence Island, Alaska (C. R.)
and analyzed at Woods Hole Oceanographic
Institution (W. W.). The dates of recording
corresponded to the height of the courtship sea-
son. No other mammals were seen in the imme-
diate vicinity during most of the listening pe-
riods, except for a few walrus, Odobenus, whose
underwater sounds were noted to be similar to
some of those reported from a captive (Schevill,
Watkins, and Ray 1966).

The recordings were made with an LC-50
(Atlantic Research) hydrophone, a preamplifier
(Watkins, 1963), and a Nagra III tape recorder.
Analysis playback was by means of a Crown
(800 series) recorder. The system was essen-
tially flat from 50 to 10,000 cps. Spectrographic
analyses were made on a Kay Electric Vibra-
lyzer.

Acoustical Results

The song of Erignathus is both complicated
and highly variable, yet by listening for an ex-
tended period an overall pattern for the song
may be noted. The entire pattern occasionally is
heard in one song; more often the song is frag-
mented with only parts of the song given and
the variations predominating. At times a short
rising trill may signal the repetition of a large
part of the song, usually with additional varia-
tions. Our listening sample appears to have
been large enough and from a sufficiently varied
locale so as to offset limiting oceanographic
factors, such as selective frequency attenuation
and temperature/pressure effects. The fact that
the song may be heard through the water-air
interface indicates a relatively intense sound.

The song of Erignathus is a highly frequency-
modulated call, much more so than that of any
other marine animal we have herad. It may be
continuous for more than a minute and is com-
posed of short oscillations of the carrier-
frequency (frequency-modulation) superim-
posed on longer-duration variations of the
carrier-frequency. The song gives the aural im-
pression of a long, siren-like oscillating warble.
The song starts at 2000 to 3000 cps and ends at
200 to 300 cps; there is an overall downward
sweep in frequency throughout the song, though
there may be several short-term upward excur-
sions. The song appears to end with a separate
unmodulated low-frequency moan of two to
three seconds duration and usually slightly de-
creasing frequency.

In our recordings, singing seals were numer-
ous and never sufficiently isolated from their
fellows to be certain of the attribution of the
entire song to one individual. However, the pat-
tern appeared generally to be the same. The
variability noted in the detail of the pattern may
be the result of individual preference.

Our representative song (Text-fig. 1 ) was as
follows:

1 ) An introductory short warble which rose
in frequency from 2500 to 3000 cps and lasted
2.5 seconds.

2) A second phrase 20 seconds in duration
in which the carrier-frequency dropped from
3000 to 1000 cps.

3) A third phrase which lasted 3.5 seconds
and rose to 2000 cps in carrier-frequency.

4) A repetition of phrase two with additional
variations, 40 seconds in duration, which
dropped to just below 1000 cps and was fol-
lowed by a pause of 15 seconds.

5) An unmodulated moan which lasted 3
seconds and fell in frequency from 400 to 300
cps.

Detailed description of the song as heard
from many individuals is as follows. The be-
ginning phrase of the song (PI. I) is a rising
warble characterized by short bursts (100
to 250 msec, long) of frequency-modulation
with oscillations of up to 1000-cps variation,
separated by periods (100-150 msec.) of either
less variation in frequency or unmodulated tone.
This first phrase of the song may last 2.5 to 8
seconds.

The introductory phrase is followed by a long
second phrase (PI. II), an oscillating warble
that may last a minute or more and that is
composed of regular frequency oscillations
produced at a relatively rapid rate (12-30 per
second) superimposed on slower oscillations of
the carrier frequency which vary at the rate of
3 per second to 1 per several seconds. The
overall frequency drops during this phrase of
the song and both the rapid frequency-modula-
tion and the slower oscillation of the carrier-
frequency occur progressively more slowly.
Thus during the later portions of the second
phrase, the song becomes more like a simple
frequency-modulated warble in which the long
carrier-frequency oscillations are of 5 to 10
seconds in duration. The sound may vary during
frequency modulation by as much as 1000 cps,
but the largest is usually about 500 cps.

A third phrase consisting of a short warble
sometimes interrupts the second phrase, usually
to be followed by a repetition of phrase two as
another “verse” of varying length. This ascend-

1969]

Ray, Watkins & Burns: The Underwater Song of
Erignathus (Bearded Seal)

81

ing warble is relatively short (3 to 7 seconds)
and has regular frequency-modulation as well as
a steadily rising carrier-frequency (PI. III).
A typical insertion of the ascending trill into the
song raises the carrier-frequency from about
1000 to 2000 cps allowing a repetition or a varia-
tion of the last portions of the song. The ascend-
ing warble is never used following a moan and
is always inserted when the carrier-frequency of
the song has dropped to 1000 cps or below.

The moan (lower portion, PI. II) appears
at the end of many of the Erignathus songs
and so we include it as a part of the total song.
Actually, there usually is a silence of up to 30
seconds (the interval is difficult to determine)
between the last part of the slowly oscillating
warble and the beginning of the moan. The
moan is always lower in frequency than the
earlier parts of the song. It is an unmodulated
tone usually of descending frequency between
500 to 200 cps and of 2 to 3 seconds duration,
contrasting sharply with the long frequency-
modulated warble that precedes it. At close
range, it is the moan that is associated with the
appearance of bubbles and the subsequent sur-
facing of the seal.

Behavioral Observations

In spite of its superficial variability, the gen-
eral pattern of the song of Erignathus is stereo-
typed and repetitive. It is complex and musical;
it is seasonally produced and apparently sexu-
ally distinctive. It may also be territorial in func-
tion. In these respects the song of Erignathus
fits the traditional usage of the term “song” as
it is applied to the complex sound combinations
of passerine birds.

In an effort to determine the role of the song
a number of seals were collected (J. B.) It is
the habit of Erignathus to swim in leads or
openings in loose pack ice and individuals are
not gregarious. Of 17 identified as singing and
collected, all were males; of another 19 collected
in the immediate vicinity of singing, 15 were
males. All of these males proved to be sexually
mature. Contrastingly, in July, though many
seals of both sexes have been observed, none has
been heard to sing. This strongly implies that
the male Erignathus is proclaiming either its
breeding territory in the pack ice or simply its
availability or perhaps both. This is not in agree-
ment with Freuchen’s (1921-24) often quoted
assertion that the song is used for communica-

— 1 — > 1 1 1 — 1 — * 1 1 > 1 ■ — —i ' 1 ' r-

0 10 20 30 40 50 60 70 80

TIME - SECONDS

Text-fig. 1. The lower portion of the drawing is a spectrographic portrayal of the characteristic (irregular
sine-wave-like) variations in the carrier-frequency of an Erignathus song. Additional modulation is
superimposed on these carrier-frequency variations and consists of relatively rapid frequency-modulation
whose swing about the carrier-frequency may be as large as 1000 cps; this is portrayed in the upper
portion of the drawing. During phrase one the frequency-modulation typically is in short bursts; phrase
two has continuous but varying frequency modulation; phrase three has slower and more regular modu-
lation; and the moan at the end is separated from the rest of the song by a silent interval and is
unmodulated.

82

Zoologica: New York Zoological Society

[54: 2

tion between mother and pup, nor with Poulter’s
( 1966) evident belief that the song has a sonar
function.

Our suggestions are reinforced by the ob-
servations of the Eskimos. Those that were inter-
viewed agreed that the song is heard only from
March through June and is associated with rela-
tively short dives of about three minutes dura-
tion. They emphasized that bubbles always ap-
pear at the surface shortly after the moan is
heard and that these bubbles are used as a con-
venient marker for the seal’s appearance where
it may be killed by the hunter.

The observation that in-air sound is used by
phocid seals in territorial or courtship activities
on land has been made for Mirounga, the ele-
phant seal, by Bartholomew ( 1952) . That sound
is important in underwater courtship in its
world of shore ice has also been suggested for
Leptonychotes, the Weddell seal, by Ray (1967).
Territory in the case of Erignathus would imply
a lead or opening in the pack ice.

Summary and Conclusions
The underwater song of Erignathus usually
consists of a long oscillating frequency-modu-
lated warble that may be more than a minute in
duration, followed by a short unmodulated low-
frequency moan. The song typically starts at
about 2000 cps with many frequency variations
and ends as low as 200 cps. The song apparently
is used only by mature males during the spring
courtship season. It is suggested that its purpose
is a proclamation of territory or of breeding
condition or both.

Literature Cited

Bartholomew, G. A., Jr.

1952. Reproductive and social behavior of the
northern elephant seal. Univ. Calif. Publ.
Zool., 47:369-472.

Burns, J. J.

1967. The Pacific bearded seal. Alas. Dept, of
Fish and Game. Juneau. 66pp.

Freuchen, P.

1921-4. Mammals. Part II, Rept. Fifth Thule
Exped., 2(4 & 5) :68-278.

POULTER, T. C.

1966. Systems of echolocation. In Les Systemes
Sonars Animaux, Ed R.-G. Busnel. Lab.
Physiol. Acous., Jouy-en-Josas, France,
1:157-185.

Ray, Carleton

1967. Social behavior and acoustics of the Wed-
dell seal. Antarctic Jour., 2(4 ): 105-106.

Schevill, W. E., W. A. Watkins, and

Carleton Ray

1966. Analyses of underwater Odobenus calls
with remarks on the development and
function of the Pharyngeal pouches. Zoo-
logica, 51(3): 103-105.

Watkins, W. A.

1963. Portable underwater recording system.
Undersea Tech., 4(9):23-24.

Acknowledgments

We wish to thank Dr. F. H. Fay of the Arctic
Health Research Laboratory, U. S. Public
Health Service, College, Alaska, for aid in the
identification of sounds. Winfred James and
numerous eskimos of Gambell, Alaska, aided us
in the field.

We also wish to thank W. E. Schevill and
Dr. R. H. Backus, both of Woods Hole Oceano-
graphic Institution, for many helpful criticisms
during preparation of the manuscript. This work
was sponsored by the following grants: the New
York Zoological Society (C. Ray); the Arctic
Institute of North America to The Johns Hop-
kins University under contractual agreements
with the Office of Naval Research (C. Ray); the
Office of Naval Research contract Nonr 4446
( W. A. Watkins) ; Federal Aid to Wildlife funds,
Pittman-Robertson Project W-6-R and W-14-R
(J, J. Burns).

1969]

Ray, Watkins & Burns: The Underwater Song of
Erignathus (Bearded Seal)

83

EXPLANATION OF THE PLATES

Plate I

The song of Erignathus begins with an introduc-
tory warble (phrase one) that alternates short bursts
of frequency-modulation separated by periods of
relatively unmodulated tone. The sounds below 2
kcps are from more distant seals. The analyzing
filter bandwidth is 200 cps.

Plate II

A later portion during the Erignathus song (phrase
two) is portrayed in the upper part of the spectro-
gram and shows rapid frequency-modulation super-
imposed upon carrier-frequency oscillations of
longer duration. The lower part illustrates a moan
at the end of another seal’s song. The effective filter
bandwidth in this analysis is 120 cps.

Plate III

Sometimes interrupting phrase two is a short rising
warble (phrase three) in which short-term modula-
tions are regular and there are no longer oscillations
as in phrase two. The analyzing filter bandwidth is
400 cps.

Inserted

Phonograph disk of the underwater song of
Erignathus (Bearded Seal).

RAY, WATKINS & BURNS

PLATE I

THE UNDERWATER SONG OF ERIGNATHUS (BEARDED SEAL)

RAY, WATKINS & BURNS

PLATE II

in co O m o in
cvJ cvi ^ O

THE UNDERWATER SONG OF ERIGNATHUS (BEARDED SEAL)

RAY, WATKINS & BURNS

PLATE III

Co

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