Zoologiculfournal ofthe Linnean Society, 67: 203-223. With 8 figures
November 1979
Two new species of nudibranchiate molluscs
from the west coast of North America,
with a revision of the family Cuthonidae
GARY C . WILLIAMS
Department @Marine Biology, San Francisco State University,
San Francisco, Caltjornia 94132
AND
TERRENCE M. GOSLINER
Department of Zoology, University $New Hampshire,
Durham, New Hampshire 03824
Acceptedjbr publication April 1978
Two species of nudibranch molluscs are described from the northeastern Pacific Ocean on the west
coast of North America. These are: a new aeolid species of Cuthona Alder & Hancock, 1855 (family
Cuthonidae) from the Oregonian marine zoogeographical province and a new dorid species of
Acanthodoris Gray, 1850 (family Onchidorididae) from the Panamic province in the Gulf of
California. The internal anatomy and external features of each species are compared with related
species. Differences in structure of the radula, reproductive system and other morphological aspects
are described. A revision of the family Cuthonidae is included. Evidence is presented to include the
genera Trinchesia Ihering, 1879, and Precuthona Odhner, 1929, within the genus Cuthona. Cuthona
alpha Baba & Hamatani, 1963, is synonymized with Catnonu columbium (O’Donoghue, 1922).We
consider the New World Cuthonidae to be composed of the following five genera: Catriona
Winckworth, 1941 ; Cuthona Alder & Hancock, 1855; Embletonia Alder & Hancock, 1851 ; Tenellia
Costa, 1877; and Tergipes Cuvier, 1805.
KEY WORDS: - Cuthonu - Acanthodoris - new species - taxonomy - anatomy.
CONTENTS
Introduction
. . . .
Cuthom coc0aEhrDtMsp. nov.
Typematerial . . .
Geographic Range
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Habitat
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External features . .
Internalanatomy . .
Discussion
. . .
Revision of the Cuthonidae
List of American Cuthonidae
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0024-1082/79/110203-2llSO2.00
11
0 1979 The Linnean Society of London
G. C. WILLlAMS A N D T. M. GOSLINER
204
Acmttha[orir serpntinduc sp. nov.
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Typematerial . . . . . . . . . .
Habitat
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External features . . . . . . . . .
Internal anatomy . . . . . . . . .
Discussion
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Acknowledgements
References
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INTRODUCTION
The aeolidacean family Cuthonidae is represented on the west coast of North
America by 12 species in three genera. On 14 January, 1972,we collected two
individuals of a previously undescribed species of Cuthona from the rocky intertidal
shores of Coleman Beach, Sonoma County, central California. Since that time, 14
additional specimenshave been collected from the same area.
The onchidoridacean genus Acanthodoris is represented by 1 1 species on the west
coast of North America, and by 18 species worldwide. On 28 March, 1972, we
collected seven individuals of a previously undescribed species of Acanthodoris from
the intertidal zone of San Felipe, Baja California, in the Gulf of California.
Cuthona cocoachroma sp. nov.
0rder N ud ibranch ia
Suborder Aeolidacea
Family Cuthonidae Odhner, 1934
Genus Cuthonu Alder & Hancock, 1855
Species C.cocoa~hromasp. nov.
(Figs lA, 2-6)
Type material. Holotype deposited at the California Academy of Sciences, San
Francisco, Invertebrate Zoology Type Series Collection, number CASIZ 00715.
Also deposited are paratype radula and jaws, numbers CASIZ 007 16, slides 533,
534, respectively. The type-locality is the rocky intertidal region of Coleman
Beach, Sonoma Coast State Park, Sonoma County, California (38O22’N lat.;
123O06’W long.) (Fig. 21, approximately 5 km north of Bodega Bay. The specific
epithet, cocoachroma, is derived from the Spanish, coca0 (=cocoa) and the Greek,
chroma (=colour) in reference to the chocolate brown colouration of the cerata.
Geographic range. Known only from Duxbury Reef, Marin County, California
(37O53‘N lat.; 122O42’W long.) and Coleman Beach, Sonoma County (Fig. 2,
Table 1).
Habitat. Coleman Beach represents a rugged, exposed rocky shore typical of
much of the north-central coast of California. Cuthona cocoachroma sp. nov. is found
in the lower zone tidal region. Individuals,wereencountered crawling on the algae
Egwgia, Ulua, Polysiphonia, and Iridea, or floating upside down on the surface film of
calm pools. The animal has not been found in association with any food substrate.
Individuals appear to be far more common in winter and early spring than in the
summer. N o individualswere encountered in the autumn.
External features. The general body shape is long and slender, tapering
posteriorly, with the head region the widest part. The anterior foot corners of the
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
205
Figure 1. A, Cuthara coco(Ichmma sp. nov. (14 mm long); B, Acanthodwir serpcntinotus sp. nov. (15 nun
long).
Table 1. Collection data for Cuthona cocoachroma sp. nov.
Date
14 January 1972
11 February 1972
25 February 1972
16 May 1972
12June 1976
29 June 1976
Location
Body lengths
(live)
Coleman Beach
Coleman Beach
Coleman Beach
Coleman Beach
Coleman Beach
Duxbury Reef
14 mm
8 mm
11-15 mm
10-14 mm
11 mm
13 mm
Number collected
2
2
7
4
1
1
206
G . C. WILLIAMS A N D T. M. GOSLINER
Figure 2. Maps showing the type localities ('I of A, Cuthom cocoachrmuz sp. nov., and B, Acadwdoris
serpnttinatm sp. nov.
ventral cephalic region are triangular but somewhat rounded at their apices. In
one 14 mm long specimen the foot is long, slender and averages approximately 1.5
mm wide; the distance between the tips of the foot corners is approximately 2 mm.
Just anterior to the foot are the elongate outer lips which surround the circular
mouth and form the oral lappets (Fig. 4A). From the anterodorsal portion of this
region extend the cephalic tentacles. These are smooth, slender and are held
approximately 90° apart in the crawling animal (Fig. 3). Just anterior to the
subcutaneous eyes originate the elongate rhinophores. These are conical, smooth
and measure 4 mm in length in one 15 mm long specimen.
The ground colour is translucent white with encrusting opaque white pigment
covering the entire dorsal side of the cephalic tentacles. This pigment also adorns
the distal half of each rhinophore and the distal apex of each ceras. The ceratal
cores vary from deep reddish-brown to dark chocolate brown.
The well-spaced cerata are arranged in 9-1 1 distinct rows on each side of the
body with 1 to 7 cerata per row. There are 3 to 4 rows of cerata on each side
anterior to the inter-hepatic region. A single ceras is digitiform, elongate, and
somewhat acute at the tip, varying from 1 to 3 mm in length (Fig. 4B).
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
207
Figure 3. Cuthona cocoachroma sp. nov. : dorsal aspect of a 14 mm long animal.
The separate male and female gonopores are located on the right side of the
body between and ventral to the first and second anterior rows of cerata. The
acleioproctic anus is located antero-dorsally to the fourth or fifth ceratal rows, in
the right posterior region of the inter-hepatic space (Fig. 4C).
Internal anatomy. The nervous system is typically aeolidacean in that the visceral,
supra-intestinal, and right parietal ganglia are fused with the right cerebral and
pleural ganglia into one complex (Fig. 5E).
The uniseriate radula is composed of 20-39 teeth. Each tooth has a central cusp
with 4 or 5 lateral denticles on each side. The length of the central cusp is variable
and may be longer than, equal to, or shorter than the adjacent lateral denticles.
The central cusp and lateral denticles are sharply pointed at their apices. The
central cusp approximates the width of the adjacent lateral denticles (Fig. 5A).The
entire radular ribbon of one specimen is 0.9 mm in length. The jaws each have a
single row of approximately 16 triangular to rounded denticles on the masticatory
edge. The thin wings of the jaws are pointed posteriorly (Fig. 5B, C).The jaws are
golden brown in colour and can be seen through the dorsal surface of the living
208
G . C. WILLIAMS AND T. M. GOSLINER
Figure 4. Cuthrma cocoachroma sp. nov.: A, ventral view of head region; B, single ceras; C, right lateral
view of'anitnal with cerata removed.
animal (Fig. 1). A single jaw plate of one specimen is 1.1 mm long and 0.8 mm
wide.
The reproductive system is typically cuthonid (Fig. 5D). The massive ovotestis
contains large male acini with numerous smaller, peripheral female acini. The
ampulla is convoluted and lies latero-ventrally to the female gland mass. The
membrane gland comprises the smallest portion of the gland complex, whereas
the mucous gland is the largest portion of the mass. The small, spherical
receptaculum seminis enters the female atrium via a short duct. The vas deferens is
extremely short and enters the penial sheath near the base. The penis has a short
recurved penial gland. The penial papilla is conical and unarmed.
Discussion.For comparative study specimens of several species of cuthonids were
collected and examined, including Cuthona concinna (British Columbia, New
Hampshire), C. nanu (New Hampshire), C. viridis (New Hampshire), C. divae
(California), Cutrionu columbianu (California), C. p n o t a (New Hampshire), and C.
oba (Florida).All descriptive material is original unless otherwise indicated.
C . cocoachroma differs from its seven sympatric congeners by its unique colour
pattern, lacking the yellow or orange pigment found in C. lagunue (O'Donoghue,
1926),C. uirens (MacFarland, 19661,C.fEawovulta (MacFarland, 1966),and C.fulgens
(MacFarland, 1966). C. abronza (MacFarland, 1966) has purple markings with
opaque white spots over the entire surface. C. albocrusta (MacFarland, 1966)
possesses opaque white speckling covering the body, and its club-shaped cerata
differ markedly from the fusiform cerata of C. cocoachroma. C. cocoachromaresembles
the sympatric C. divue (Marcus, 1961)and the allopatric C. nanu (Alder& Hancock,
18421, but is most similar to the allopatric C. concinnu (Alder & Hancock, 1843)
(Table2).
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
209
Figure 5. Cuthona cocoachrm sp. nov.: A, five radular teeth; B, inner view of two jaw plates, with
detail of denticulations on masticatory edge; C, masticatory edge of jaw plate; D, reproductive
system; E, nervvus system.
The colouration of C. cocoachroma differs from that of the three species listed in
Table 2. Red-brown pigment is found in the digestive gland tissue of the cerata
of C. cocoachroma and C. concinna. However, specimens of C. concinna always possess
blue or white flecks on the ceratal epithelium (O'Donoghue, 1922; Alder 8c
Hancock, 1845 ;present study)which is lacking in all specimens of C. cocoachroma.
C. concinna possesses five or six preanal rows on each side with a total of 10-12
rows per side, while C. cocoachroma has three or four preanal rows with nine to ten
rows along its length. This pattern was consistent in seven specimens of C. concinna
and fiveC. cocoachroma, all ofvarying lengths.
The radular teeth of C. cocoachroma and C. conn'nna are similar in shape, number
and configuration. The central cusp may be shorter than, equal to, or longer than
Receptaculutn
seminis
Bursa
copulatrix
Vas deferens
Penial gland
Rhinophores
and cephalic
tentacles
Ampulla
Radula
9-1 1 rows; 3-4 preanal generally
Cerata
small, spheroid with long narrow
stalk
absent
elongate, convoluted; lateroventral to female gland mass
short; straight
very short; directed anteriorly
lateral or posterior to
rhinophores
20-39 teeth; 4-5 denticles per
side
rhinophores 2X length of
cephalic tentacles
translucent white with encrustations of opaque white on cephalic tentacles, rhinophores, and
tips ofcerata; ceratal cores
chocolate brown
Colour
cocoachroma sp. nov.
saccate; embedded in female
gland mass
elongate; coiled
elongate, convoluted; directed
posteriorly
large, saccate with short wide
stalk
present
20-30 teeth; 3-7 denticles per
side
rhinophores generally equal in
length to cephalic tentacles
translucent white with opaque
white on cephalic tentacles,
rhinophores, and tips ofcerata;
ceratal cores purple-brown to
rust, with metallic silver-blue
on ceratal sheath
10-12 rows; 5-6 preanal generally
extend anterior to rhinophores
concinna
numerous rows; 7-1 1 preanal always
anterior to rhinophores
c-rIatal rows very nutiierous; 3-8
preatial always anterior to
rhinophores
21-32 teeth; 3-10 lateral denticles
saccate; embedded in female gland
mass
elongate; coiled
conical; directed posteriorly
saccate; stalk elongate
absent
sacrate; embedded in female gland
stalk short
present
elongate
conical; directed anteriorly
niass
rhinophores 1.5X length of cephalic
tentacles
rhinophores 1.5-1.7Xlengthof
cephalic tentacles
18-27 teeth; 5-10 lateral denticles
translucent white with opaque white
on tips of cerata; ceratal cores
rose-orange to salmon
nana
u.atislucenc white to pink; tip of
c'rrata opaque white; ceratal cores
rose t o burnt umber
diuae
Table 2. Comparative characteristics of four Cuthona spp.
0
N
c
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
A
211
C
Figure 6 . Diagrams of the reproductive system of A, Cuthona cocoDchroma sp. nov.; B, C. concinna (Alder
& Hancock, 1843); C, C. nana (Alder & Hancock, 1842).
the adjacent denticles in C. cocoachroma while in all specimens of C. concinna
observed it exceeds them.
Nine species of Cuthona have been described as lacking a penial stylet (Burn,
1973). Of these C. concinna is the only species which resembles C. cocoachroma in its
external morphology. 0ther aspects of their reproductive morphology clearly
differentiate C. cocoachroma from C. concinna (Fig. 6). In C. concinna the ampulla is
saccate and embedded in the dorsal surface of the female gland mass while in C.
cocoachroma the ampulla is elongate, convoluted and situated ventro-lateral to the
female gland mass. The vas deferens in C. concinna is elongate and prostatic while it
is short and non-prostatic in C. cocoachroma. The penial gland of C. com'nna is
elongate, convoluted and directed posteriorly while that of C. cocoachroma is short
and directed anteriorly. C. concinna contains a large proximal receptaculum
seminis with a short, wide stalk as well as a vestigal distal bursa copulatrix, while C.
cocoachroma has a receptaculum seminis inserted on a narrow elongate stalk and
lacks a bursa copulatrix. I t is unlikely that these differences merely reflect
intraspecific variations as all specimens were fully mature and the differences were
consistent.
REVISION OFTHE CUTHONIDAE
Miller ( 19 7 7 has recently applied the familial name Tergipedidae
(=Cuthonidae)on the basis of priority. This action is inappropriate in view of the
ruling of the International Commission of Zoological Nomenclature ( 1966)
which places the Cuthonidae on the official list of family group names in
zoology.
212
G. C. WILLIAMS AND T. M. GOSLINER
The distinctions between the various genera of the Cuthonidae have been the
subject of considerable confusion. Burn ( 1973) and Miller ( 197 7 ) provide
excellent historical synopses, which will not be repeated here. We agree with
Miller’s (197 7 ) contention that Trinchesia Ihering, 1879; Xenocratena Odhner,
1940; Njuya Marcus 8c Marcus, 1960; Narraeolidia Burn, 1961; Tooma Burn, 1964;
and Selva Edmunds, 1964 represent junior synonyms of Cuthona Alder & Hancock,
1855, but agree with Burn (1973) that Catriona Winckworth, 1941, is distinct from
Cuthona.
That Trinchesia cannot be separated from Cuthona is here further substantiated.
Odhner (1939) stated that Cuthona could be separated from Trinchesia (then
considered as Cratenu) by the ceratal rows extending anterior to the rhinpphores
in Cuthona and the most anterior cerata always posterior to the rhinophores in
I‘rinchesia. however, the cerata of juvenile Cuthona concinna may not extend
anterior to the rhinophores, whereas large specimens always have ceratal rows
anteriorly (present study). Cuthonu caerulea (Montagu, 18041, type species of
Trinchesia, possesses ceratal rows anterior to the rhinophores (Marcus, 1955).
Therefore, ceratal arrangement cannot be used as a basis for generic separation.
Miller (1977) argued correctly that the possession of accessory denticles in the
radular teeth is not useful in separating Catriona and Cuthona. However, the
possession of bristle-like denticles on the masticatory border of the jaws appears
to be unique to Cutriona. Catriona aurantia (Alder 8c Hancock, 1842), type species
of the genus, has bristle-like denticles, contrary to Miller’s contention (Edmunds,
1968; present study). Also, the possession of a pre-radular tooth, a quadrate
rather than angular cutting edge of the radular teeth, and a radula possessing
more than 50 teeth are unique and consistent characters within the described
species of Catriona. For these reasons we agree with Burn (1973) that Catriona
represents a distinct and valid genus within the Cuthonidae.
Catriona maua Marcus & Marcus, 1960, clearly fits Burn’s ( 1964) revision of the
genus based on C . aurantia. Two other species, C. columbiana (O’Donoghue, 1922)
and C. gymnota (Couthouy, 1838) were placed in Catriona by Marcus 8c Marcus
( 1960) without substantiation. Examination of O’Donoghue’s ( 1922) description
of Amphorina columbiana, with short penial stylet and tapered radula, whose
numerous teeth have secondary denticles and a depressed central cusp, supports
the placement of the species in Catriona. Eolis gymnota is clearly a cuthonid based
on Couthouy’s (1838) description of the anus high on the body (acleioproctic)
and rounded head. However, a more exact placement of the species is not
possible on the basis of the original description. Gould 8c Binney ( 1870) added
no new information useful to its generic placement. Bergh ( 1885) described the
radular teeth and jaws of Eofis gymnota and placed it in Cratena. The numerous
teeth of the tapered radula, as well as the unique denticles of the masticatory
border, indicate that it does belong in Catriona.
Baba 8c Hamatani (1963) described Cuthona alpha from Japan while
MacFarland ( 1966) described Cratena spadix from California. Roller ( 1969), in a
very thorough analysis, established that C . spadix is a junior synonym of C . alpha.
in a re-examination of O’Donoghue’s ( 1922) description of Amphorina
columbiana it became apparent that it was very similar to Cutriona alpha. The
colouration of C . columbianu, opaque white with vermilion cerata with a grey hue,
is identical to that described by MacFarland. The radula is the same in both taxa,
and both have a short penial stylet. Based on this information, Cuthona alpha
NUDIBRANCHIATE MOLLUSCS FROM N O R T H AMERICA
213
Baba and Hamatani, 1963, is here considered as a junior subjective synonym of
Catriona columbiana (O’Donoghue, 1922), syn. nov.
Miller ( 197 7 ) stated that differences between Catriona columbiana (as C . alpha)
and specimens he collected from New Zealand were insignificant and within the
range of intraspecific variation. In all descriptions the radular teeth of C .
columbiana contain two large denticles on each side of the central cusp, whereas
Miller’s New Zealand specimens have three. Contrary to Miller’s contention,
Roller ( 1969) substantiated that Japanese specimens of C . columbiana also possess
bristle-like denticles on the jaws. However, it is not clear from Miller’s figure
(1977: fig. 4b) whether the masticatory border is damaged or irregularly
denticulate. The most substantial difference between Catriona columbiana and
Miller’s specimens is in the reproductive system. C . columbiana contains a short
penial stylet while the New Zealand animals possess an unarmed, conical penis. It
is therefore unlikely that Miller’s specimens are conspecificwith C . columbiana.
Moore ( 1964) regarded the New England species of Catriona as Cratena aurantia.
However, these animals are virtually identical with Couthouy’s ( 18381, Gould &
Binney’s (1870) and Bergh’s (1885) descriptions of Catriona gmnota. Ecologically,
both taxa are found at the base of the stolons of Tubularia (Gould & Binney,
1870; present study). The egg masses of C . gymnota are identical with all other
material from New England (Gould 8c Binney; 1870: fig. 520). Similarly, there is
no basis for differentiating specimens of Catriona gymnota of the western Atlantic
from the European Catriona aurantia. Both taxa have similar colouration
(Couthouy, 1838; Gould & Binney, 1870; Alder & Hancock, 1842), radular
configuration and reproductive morphology (Odhner, 1939; present study).
Therefore, Eolis auruntia Alder 8c Hancock, 1842, is here regarded as a junior
subjective synonym of Catrionagmnota (Couthouy, 1838), syn. nov.
Subsequent examination of Catriona oba Marcus, 1970 (present study) confirms
that it is properly placed in Catriona. In addition to the characters described by
Marcus, specimens from Florida possessed bristle-like denticles on the
masticatory border.
Precuthona was described by Odhner ( 1939) to accommodate the single species
Eolis peachi Alder 8c Hancock, 1848. Odhner maintained that E. peachi differed
from members of Cuthona since there are rows of the posterior right ‘liver’
extending anterior to the anus, thus converging with the cleioproctic condition.
Observation of numerous cuthonid specimens from the New Hampshire coast
(Brian Rivest and Alan Kuzirian, personal communication; present study)
suggests that generic and specific differences between Cuthona and Precuthona and
their respective type-species are at best questionable. Alder & Hancock ( 1855)
illustrated radular teeth of Eolis nana (pl. 47, figs 16, 1 7 ) and E . peachi which
appear significantly different in shape. Specimens of a single reproducing
population from the New Hampshire coast contain radular teeth which resemble
those of both species in Alder & Hancock’s figures, and the shape of teeth within
the radula of a single specimen may vary considerably. AS older teeth are more
similar to those attributed to E. nana and newer teeth more closely resemble
those depicted for E. peachi, it would appear that the two ‘species’ may in fact be
conspecific, representing different age classes. Odhner ( 1939) described the
reproductive system of Cuthonu nana as lacking a penial gland. Numerous
specimens from New Hampshire all had a penial gland, even those only 3 mm in
length. We believe that either Odhner did not see the penial gland or he was
214
C . C. WILLIAMS A N D T. M . GOSLINER
dealing with a different taxon. The first possibility seems most likely in view of
the extreme similarity of the radular teeth between his specimens, those of Alder
& Hancock and our own. The cerata of specimens from the New Hampshire
coast also show similarities to plates of both species in Alder & Hancock (Family
3: pl. 25, figs 1-4; pi. 10, figs 1-4). Small specimens have all the cerata of the
posterior right digestive system posterior to the anus. Large specimens have one
or two ceratal rows of the posterior system anterior to the anus as described by
Odhner ( 1929) for Precuthonu peachi. Brian Rivest (personal communication) has
encountered specimens of intermediate size in which the right posterior system is
in the process of its anterior proliferation and lies dorsal to the anus.
In view of the fact that the major criteria used to separate Cuthonu nana from
Precuthona peachi, the radula and ceratal arrangement, vary within a single
population and can be correlated with age, there is little basis for separating the
two species. Therefore, we consider Eolis peachi Alder & Hancock, 1848, to be a
junior subjective synonym of Cuthona nana (Alder & Hancock, 18421, syn. nov.
Since Precuthona peachi was designated as the type-species of Precuthona by
Odhner (1929) the genus must therefore be regarded as a junior synonym of
Cuthona Alder & Hancock, 1855, syn. nov. The other species previously placed in
Precuthona is P. divue Marcus, 1961. The morphology of P. dime is similar to C.
nana. The shape and number of the radular teeth are very similar. Both species
are associated with athecate hydroids (Hydractinia spp.1. Both species have a
simple penial papilla with an elongate, conical penial gland. There are three to
eight preanal ceratal rows in P. divae while there are seven to eleven in C . nunu.
The most substantial difference is in the reproductive system. P. divae has a
proximal receptaculum seminis and a distal bursa copulatrix (MacFarland, 1966,
as C. rosea) while C. nunu lacks a bursa copulatrix. In other regards P. divue does
not differ markedly from C. nuna and other members of Cuthona. The fact that C.
concinna also possesses a bursa supports the placement of P. dime within Cuthona
and it is here considered as Cuthonu d i v a (Marcus, 19611, comb. nov. Miller's
( 19 7 7) separation of the Cuthonellinae and Cuthoninae must similarly be
suppressed as it is based on differences which are found in juvenile versus adult
Cuthona nunu.
A summary of the proposed nomenclatural changes and a revised list of
American cuthonids is as follows.
LIST OF AMERICAN CUTHONIDAE
Catriona Winckworth, 194 1
1. columbiana (O'Donoghue, 1922). British Columbia-California, Japan
Amphorina columbiana O'Donoghue, 1922
Cuthonu alpha Baba & Hamatani, 1963, syn. nov.
Cratena spadix MacFarland, 1966, syn. nov.
Catrionu columbium; Marcus & Marcus, 1960
Catriona alpha; Roller, 1969
2. gymnota (Couthuoy, 1838). North American and European Atlantic
Eolis gymnota Couthuoy 1838
Eolis aurantia' Alder & Hancock, 1842, syn. nov.
NUDIBRANCHIATE MOLLUSCS FROM N O R T H AMERICA
Eolis aurantiaca; Alder & Hancock, 1855
Montaguagouldii Verrill, 1874, syn. nov.
Cratena gymnota; Bergh, 1885
Cratena aurantia; Odhner, 1939; Moore, 1964
Catriona aurantia; Winckworth, 1941
3. o6a Marcus, 1970. Brazil, Florida
Cuthona Alder 8c Hancock, 1855 (= Trinchesia Ihering, 1879 ;
Precuthona Odhner, 1.929,syn. nov.)
1. abronia (MacFarland, 1966).Washington-California
2. albocrusta (MacFarland, 1966).Washington-California
3. cmrulea (Montagu, 1804).Mediterranean, Brazil
4. cocoachroma sp. nov. California
5. concinna (Alder 8c Hancock, 1843). Circumboreal, North America, Europe
6. d i m e (Marcus, 196l), comb. nov. Washington-California
7. Jlauouulta (MacFarland, 1966). California
8. fulgens (MacFarland, 1966). California
9. georgzana (Pfeffer, 1886). S. Chile
10. lagunae (O'Donoghue, 1926). California
11. nunu* (Alder 8c Hancock, 1842). Circumboreal, North America, Europe
Eolis nana Alder & Hancock, 1842
Eolispeachi Alder & Hancock, 1848, syn. nov.
Cuthona nanu; Alder 8c Hancock, 1855
Precuthonapeachi; Odhner, 1929
12. odhneri Marcus, 1959. S. Chile
13. perca (Marcus, 1958). Caribbean, Hawaii
14. ru6ra (Edmunds, 1964).Jamaica
15. tina(Marcus, 1957). Brazil
16. uirens (MacFarland, 1966). California
17. uiridis (Forbes, 1840). North American and European Atlantic
Embletonia Alder 8c Hancock, 1851
1. euelinae Marcus, 1957. Brazil
Tenellia Costa, 187 7
1. adspersa' (Nordmann, 1845).Widespread, Americas, Europe, Japan
Tergipes Cuvier, 1805
1. tergipes * (Forskal, 17 75). N. and S. American Atlantic, Europe
* Indicates type-species.
215
C. C. WILLIAMS ANDT. M. GOSLINER
Acanthodorisserpdnotus sp. nov.
(Figs lB, 7 , 8)
Type material. Holotype deposited at the California Academy of Sciences, San
Francisco, Invertebrate Zoology Type Series Collection, bearing number CASIZ
007 17. A whole paratype is numbered CASIZ 007 18, and a paratype reproductive
system, nervous system, radula and labial cuticle are deposited as CASIZ 007 19,
slides 535, 536 respectively. The type locality is the boulder-strewn muddy shores
approximately 2km north of San Felipe, Baja California, Mexico, in the
northern region of the Gulf of California (31°10'N lat.; 114O50'W long.) (Fig.
2). This represents the only known locality. We derive the specific epithet,
serpentinotus from the Latin serpentis (=snake), and Greek notos (=back), in
reference to the presence of conspicuous, narrow papillae on the animal's dorsal
surface.
Habitat. The intertidal region just north of San Felipe is bathed in nutrient-rich
water from the nearby Colorado River delta, which empties into the northernmost
region of the Gulf of California. The intertidal zone here is composed of a layer of
coarse silt strewn with boulders of varying size. Shallow tidepools are present on
the silt surface. All individuals of Acanthodotrs
' serpatinotw sp. nov. were found
Figure 7. Acanthodair scr'pcntinotuc s p nov.: dorsal aspect of a 15 rnrn long animal.
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
217
under these boulders. They appeared to be associated with an undetermined
species of ctenostomatous ectoproct.
External features. The general body shape is ovoid with a pronounced posterior
visceral hump. The body is widest anteriorly. The body length varies from
7-16 mm. A 15 mm animal, 10 mm wide, had a foot 5 mm wide and 1 1 mm in
length. The dorsal surface is covered with conspicuous papillae 0.5-1.5 mm in
length. The labial tentacles surround the mouth anterior to the foot and are
acute at their apices (Fig. 8B).
The rhinophores are elongate, lanceolate with mammiform apices. The
rhinophoral cores are surrounded by 15-20 lamellae for4 of their length.
The branchial plume is composed of seven bipinnate gills, approximately
3 mm in length. The branchial plume is bilaterally symmetrical (Fig. 7). The
rJl
.
......
,.:..
:..:.
40pm
Figure 8. A
c
A* scrpeneinohu sp. nov.: A, labial cuticle with detail of a single rodlet; 8 , ventral
view of animal; C, reproductive system; D, teeth from right half-row of radula.
218
C . C. WILLIAMS A N D T. M. GOSLINER
hermaphroditic gonopore is located on the right side of the body, between the
dorsum and foot, in the anterior quarter of the body.
The ground colour of the body is dull reddish-brown to pinkish-orange or
salmon-orange (Fig. 1). The papillae are reddish-brown or pinkish to rust-brown
at the base, and dull whitish in the distal half. The rhinophores have whitish
cores surrounded by reddish-brown colouration in the lamellar region. The gills
are translucent white with speckled black pigment. The foot is dull translucent
white, spotted with reddish-brown and with brownish lines around the margin.
The lateral sides of the foot have very concentrated brown to pinkish-brown
speckling on a dull grey ground colour. Dense speckling occurs on the
underside of the dorsum around the oral tentacles and also on the anterior
margin of the foot. Less dense speckling occurs throughout the sole of the foot
(Fig. 8B).
Internal anatomy. The radula (Fig. 8D) has 26-29 rows of teeth, with five outer
laterals and one inner lateral per half row. A rachidian tooth is absent. The
median surface of the large inner laterals contains two to six small denticles. The
diminutive outer laterals lack denticles.
The labial cuticle (Fig. 8A) contains numerous rodlets on the anterior surface.
These rodlets are 30 to 45 pm in height and possess 7 to 9 denticles.
The reproductive system (Fig. 8C) is described from the dissection of a single
10 mm specimen. The ovotestis is large and partially embedded in the digestive
gland. The preampullar coelomic gonoduct is narrow, short and enters into a
broad, straight ampulla. The ampulla gradually narrows into a short
postampullar coelomic gonoduct. From this point the male and female systems
divide. The vas deferens is narrow and highly convoluted, opening into a large
bulbous penis sack which opens at the gonopore. The female system begins as a
thick glandular tube of the albumen gland which gradually increases in diameter
as it enters the female gland mass proper. From the albumen gland extends the
membrane gland which continues into the massive mucous gland. The mucous
gland is elongated distally near the gonopore. Along the oviduct, extremely close
to the separation of the male and female systems, is the elongate uterine duct
which enters the large bursa copulatrix. At this point two other ducts exit from
the bursa. The first is the duct of the receptaculum seminis. The receptaculum is
approximately 4 the size of the bursa copulatrix. The second duct is the
highly convoluted and extremely long vaginal duct. The vaginal duct exits at the
gonopore between the penial and oviducal apertures.
Discussion. The genus Acunthodoris is composed of 15-1 9 previously described
species. Of these, all but one have been encountered from the polar to temperate
regions of the world. Only A . pinu Marcus & Marcus, 1967, is known from the
subtropics (Gulf of California). Nine species are known from the boreal to
temperate regions of the northeastern Pacific coast, from Alaska to California.
One of these, A. pilosu (Abilgaard, 1789), is also known from the American and
European North Atlantic and Japan. A . citrinu Verrill, 1879; A . stellutu Verrill,
1879; and A . omutu Verrill, 1879, from the northwest Atlantic are here
considered as junior synonyms of A . pilosa. Verrill described only external
characteristics but his descriptions are within the range of variation of A . pilosa in
New England. A . subquadrutu (Alder & Hannock, 1845) is also a junior synonym
of A . pilosa (Hunnam 8c Brown, 1975).One or two species are known from boreal
South America. A . fulklundicu Eliot, 1907, from the Falkland Islands may be
NUDIBRANCHIATE MOLLUSCS FROM NORTH AMERICA
219
synonymous with A. vatheleti Mabille & Rochebrune, 1889, from Cape Horn.
However, the description of A . vatheleti is too superficial for proper comparison.
Three to five additional species are known from southern New Zealand,
Tasmania and Australia. Bergh (1905), in his original description, considered the
possibility that A. pilosa novaezealandiae may be a junior synonym of A . mollicella
Abraham, 18 7 7, but did not resolve the problem. Further anatomical investigation of Abraham's specimens by Eliot (1907) substantiated the synonymy. Eliot
also suggested that A . metulfera Bergh, 1905, may be synonymous with A . globosa
Abraham, 1877. Burn (1969) described A . nanega and noted differences from
other regional species. One additional species, A . uchidai Baba, 1935, is known
from northern Japan. A . serpd'3mtu-s sp. nov. represents the second subtropical
acanthodorid from the Gulf of California. It is interesting to note that the Gulf
of California is immediately adjacent to the Californian zoogeographical
province, the zone with the largest number of sympatric species within the genus.
Therefore, even the two subtropical representatives are directly associated with a
boreal and temperate fauna which has undergone substantial speciation.
The external morphology of Acanthodoris species is generally uniform. Most
species have a moderately depressed, ovoid body with elongate rhinophores and
soft, long dorsal papillae (with the exception of A . uchidai, which has a smooth
dorsum). The notum frequently contains dense spicules. There is generally
interspecific variation in the number and elaboration of the branchial plumes
(Table 3). Several species exhibit limited intraspecificvariability in gill number. A .
serpentinotus was found to have only seven branchial plumes. These are proportionately larger and more bilaterally symmetrical in their arrangement than
in any other known species. Also, in most species the most anterior plume is the
largest. However, in A . serpentinotus the two most lateral gills are largest. The
acanthodorid body shape is usually ovoid with the anterior margin being the
widest part of the body. Only A. atrogriseata O'Donoghue, 1927, has been
reported to have a truly ovoid form, with the widest portion in the mid-region of
the body. A . serpentinotus has been observed to assume both body shapes.
A . pilosa is the only acanthodorid reported to have a wide range of variability in
its colour. A . serpentinotus is unique among the acanthodorids in having a brown
ground colour with opaque white markings on the gills. Acanthodoris brunnea
MacFarland, 1905, and A . rhodocerm Cockerel1 & Eliot, 1905, have a brown
ground colour, but have black-tipped papillae and yellow markings on the
dorsum which are absent in A. serpentinotus. The colouration of living A .
falklandica, A . globosa, A . mollicella, A . metulijera and A . pilosa novaezealandiae is
unknown.
In all acanthodorids for which it is described, the labial cuticle contains an
armature of rodlets. The strength and elaboration of these rodlets is variable, but
in most, if not all species, the rodlets are variously denticulate. It is unlikely that
the dentition of the rodlets is valuable in specific separation.
There is little interspecificvariability in the radula of Acanthodoris. A rachidian
tooth is never present. The innermost laterals are significantly larger than the
outer laterals. The number of outer laterals varies from four to seven on each
side. Most species have little variation in the number of outer laterals but A.
falklandica encompasses the entire range of the genus. The large inner laterals
contain varying numbers of denticles on their inner face, and this variation is
considerable within a single radula. A . brunnea has the most numerous denticles
220
G . C. WILLIAMSANDT. M . GOSLINER
of any species, with up to 22. Those species with radular formulae most closely
approaching A . serpentinotus are A . pinu, A . pilosa, A . lutea, A .falklandica, A . brunnea
and A . atrogriseata. However, all have dentition of the large laterals which differs
to varying degrees from that of A . serpentinotus (Table 3).
The pseudo-peritoneum and its degree of pigmentation was considered by
MacFarland (1925, 1926). He described the degree of pigmentation of the
visceral membrane for several species of Acanthodoris. The pseudo-peritoneum of
a single specimen of A . serpentinotus was highly pigmented with dense, black
granules. However, upon dissecting several specimens of A . pilosa it was noted
that the degree of pigmentation is extremely variable. This same variation has
also been observed in HalZuxa chani Gosliner & Williams, 1975. Due to high
intraspecific variation in several species it is unlikely that it can be utilized for
taxonomic separation.
The penis of A . serpentinotus is unarmed. The penis of most acanthodorids has
been described (Table 3). For the majority of species there are contradictory
reports as to its armed or unarmed character. It is uncertain whether this contradictory information is a result of intraspecific variation or error. Admittedly, it
is difficult to discern the penial armature, particularly when the penis is not fully
protruded. The determination of the armature requires microscopic
examination of squashed or serially sectioned material. Comparison of the
penial armature of the species of Acanthodoris can, at this time, only be
speculative.
Two other components of the reproductive system vary significantly. The size
of the receptaculum seminis relative to the bursa copulatrix seems to be constant
within a single species (Table 3). In A. serpentinotus, A . brunnea, A . falklandica, A .
hudsoni, A . metulfera, A . pilosa novaezealandiae, A . pina and A . rhodoceras the
receptaculum is substantially smaller than the bursa, while in A . lutea, A .
nunairnoensis and A . pilosa the receptaculum is equal to or larger than the bursa. A.
rhodoceras is unique in possessing an additional vaginal vesicle (MacFarland,
1925; Marcus, 1961; present study).
The relative length and elaboration of the vagina is an important diagnostic
character in separating species (Table 3). While Bergh ( 1880) described the vagina
of A. pilosa as being “extremely long’’ his drawing (pl. 13, fig. 5) indicates that it is
of relatively moderate to short length. Dissection of numerous specimens of A.
pilosa from northern New England indicates that the vagina is indeed relatively
short. A . serpentinotus has an extremely long vagina which is highly convoluted. A.
lutea and A . nunairnoensis also share this characteristic.
A. pina Marcus 8c Marcus, 1967 and A . serpentinotus occur in the northern Gulf of
California. Owing to their geographical proximity a more detailed comparison of
the two species is warranted. The colouration of the two species differs markedly.
A . pina is bright red and black in contrast to the drab red-brown colour of A .
serpentinotw. The rhinophores are proportionately larger in A . pina while in A.
serpentinotw the papillae are more numerous. A . serpentinotus possesses papillae
within the area circumscribed by the branchial plumes, whereas they are absent in
A . pina. The branchial plumes are proportionately larger in A. serpentinotus, with
the two lateral gills being the largest. In A . pinu the most anterior gill is the largest.
The labial rodlets of A . pinu are shorter ( 15-20 pm in a 14 mm specimen, Lance,
1968) and more numerous than those in an 11 mm specimen of A . serpentinotus
(30-45 pm). Unfortunately a comparison of the reproductive organs of the two
5-7 *
rhodoceras Cockerell & Eliot, 1905
"Continued or added in this study.
-
10
32-37(4-6.1.0.1.4-6)
9
'
7-8
7-90
5-7
nanaimoensis O'Donoghue, 192 1
nanega Burn, 1969
pilosa (Abilgaard, 1789)
pina Marcus & Marcus, 1967
uchidai Baba, 1935
vatheleti Mabille & Rochebrune, 1889
37-43(5-6.1.0.~ 5 - 6 ) ~
35(5.1.0.1.5)
25-3 1(Q-6.1.O.1.4-6)'
28-34(4-6.1.0.1.4-6)
7-9
mollicella Abraham, 1877
'7
40(7.1.0.1.7)
7
metulfera Bergh, 1905
serpenthotus sp. nov.
30-39(54.1.0.1.5-6)*
9*
lulea MacFarland, 1925
-
30(7.1.0.1.7)
26-29(5.1.0.1.5)*
24-37 (6.1.0.1.6)
34(7.1.0.1.7)
27(5-6.1.0.1.5-6)
7
5
'
globosa Abraham, 1877
hudsoni MacFarland, 1905
28-30(7.1.O.1.7)
26-27(4.1.0.1.4)
24-30(6-7.1.0.1.6-7)*
39(8.1.0.1.8)
28(4-1.1.0.1.4-7)
7
70
9
9-10
7-10
caerulescas Bergh, 1880
falklandica Eliot, 1907
a n a t a O'Donoghue, 1927
atrognseala O'Donoghue, 1927
brunnea MacFarland, 1905
Species
4)
-
0
2-6 *
rs < bc"
2-7 *
-
(4)*
rs<bc
4)
-
very short
w/vesicle*
very long'
short
long
rs < bc*
-
very long'
-
long
rs=bc*
rs < bc
(4)
rs< bc
(4)
rs > bc
slightly
rs < bc
0-8 *
2-3
5-15*
1-3
3-7
3-4
0-5*
long
moderately
long
very long
rs< bc
(+)
-
3-4
4-7
long
short
rs< bc
7
New Zealand
British Columbia to California
Alaska
Falkland Islands
British Columbia
British Columbia
California
Lord Auckland Islands (New Zealand)
Tasmania
-
-
Japan
Chile (Cape Horn)
unarmed British Columbia to California
- Australia (Victoria)
armed Northern Pacific & Northern Atlantic
armed or Gulf of California
unarmed
armed or California
unarmed*
unarmed" Gulf of California
armed
armed
unarmed California
armed
armed or
unarmed
unarmed
armed
armed
very short
rs< bc
(+)
-
-
-
-
-
7-9
9-10
8-9
14-22"
Table 3. Comparison of world species of Acanthodoris
I
1c
fi
222
G. C. WILLIAMS AND T. M. GOSLINER
species lacks precision owing to the incomplete description of the reproductive
system of A. pinu. I t appears, however, that the vaginal duct of A. pinu is not as
elongate and convoluted as in A. serpentinotus.
ACKNOWLEDGEMENTS
We wish to thank Dr Hans Bertsch, Mr Michael Gosliner and Mr Scott C.
Williams for their assistance in the collection of specimens from the Sea of Cortez
and from central California. Scott Williams also provided valuable help in the
preparation of the colour plate. Ms Bonnie J. Gosliner typed several drafts of the
manuscript and added editorial comments. We also extend thanks to Dr Robert
Beeman of San Francisco State University, Drs Larry G. Harris and Alan M.
Kuzirian of the University of New Hampshire and Mr Brian Rivest of the University
of Washington for their advice and comments. Dr T. E. Thompson of the
University of Bristol provided additional interest, encouragement and suggestions
concerning this work.
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ABBREVIATIONS USED IN FIGURES
a
am
bc
cn
CPPW
Ct
e
f
fC
gP
ihh
It
m
od
01
anus
ampulla
bursa copulatrix
cephalic nerves
cerebral/pleural/parietal/
supra-intestinalhisceral
ganglionic complex
cephalic tentacle
eye
foot
foot corner
gonopore
inter- hepatic hump
labial tentacle
mouth
oviduct
outer lip (oral lappet)
Ot
P
Pdg
Pg
P"
PS
rh
rs
V
vd
9gm
9gp
6~
ovotestis
penis
pedal ganglion
penial gland
pedal nerve
penial sheath
rhinophore
receptaculum seminis
vagina
vas deferens
female gland mass
female gonopore
male gonopore