Opisthobranchs from Florida and the Virgin Islands

OPISTHOBRANCHS FROM FLORIDA AND THE VIRGIN ISLANDS

EVELINE AND ERNST MARCUS Department of Zoology, University of Sao Paulo, Brazil

ABSTRACT A total of 15 species are listed and described, 14 opisthobranchs and one prosobranch (Lamellaria). They were collected chiefly at the Virgin Islands and on the coast of Florida; some are from the Bahamas and British Honduras. The collection contains the first Atlantic Hexabranchus, H. morsomus, n. sp. (Figs. 46-47), and contributes to a better knowledge of some species of M6rch and Bergh, described in the past century. Two species hitherto known only from Japan are remarkable.

INTRODUCTION Dr. Frederick M. Bayer sent us for determination material from the collections of The Marine Laboratory, University of Miami. From this material we were able to identify 14 species of opisthobranchs and one Lamellaria. The animals came from various places on the coast of Florida, the Virgin and Bahama Islands, and from British Honduras. Since this material was gathered on field trips, during which mainly conspicuous benthonic slugs are obtained, it has little in common with Dr. Diva Diniz Correa's collection from the Miami area (Marcus, 1960b), selected in the laboratory out of growth on panels which hung from the pier of The Marine Laboratory, Univer- sity of Miami (Smith, Williams, and Davis, 1950: 133). Several collecting trips were made to St. John, Virgin Islands, thus to the neighborhood of St. Thomas and St. Croix where A. H. Riise, A. S. Oersted, and others caught and preserved many sea-slugs which were studied by O. A. L. March and R. Bergh. In recognition of their work a latinized Danish word is chosen as the name for a new species in the present collection, the first Hexabranchus from the Atlantic Ocean. Some redescriptions advance our knowledge of pre- viously known species from the Virgin Islands. Two specimens complete the status of the only W,estern Atlantic species of the rare genus Phyllidiopsis, a single slug of which was dredged off west Florida by the U. S. steamer BLAKE in 1877-78. We thank Dr. Frederick M. Bayer for revising the language in our manuscript and reading the proofs. All specimens and slides were returned to The Marine Laboratory, University oi'Miami. 1962] Marcus & Marcus: Opisthobranchs 451

EXPLANATION OF LETTERING a-albumen gland. n-nerve rIng. am-ampulla. ni-nidamental duct. ar-anus. o-oesophagus. h-clustered gland. oe-oral tube. c--collar. p-pems. cc-buccal ganglia. q-prostate. co-blood gland. r-retractor. d-radula. re-right fold of penial sheath. e-efferent duct. s-stomach. er-Ieft fold of penis sheath. sa-salivary gland I-insemination duct. se-oesophageal pouch. g-ptyaline gland. sr-seminal groove. II-hermaphrodite duct. t-spermatheca. i-intestine. u-pharynx. ii-lip. ue-glandular part of oesophagus. io-foot. un-duct of ptyaline gland. ill-duct of oesophageal gland. v-vagina. iz-gizzard. va-genital apertures. j-oral vestibule. w-winding gland. k-tentacIe. x-rhinophore sheath. I-liver branches. y-spermatocyst. m-mucus gland. z-muscle. mo-mouth. ze-oesophageal gland. zi-gills. SYSTEMATICSECTION Class GASTROPODA Subclass OPISTHOBRANCHIA Order CEPHALASPIDEA Suborder PHILINACEA Family AGLAJIDAE Chelidonura evelinae Marcus, 1955 Material.-1. Upper Long Reef, Dade County, Florida; Gilbert L. Voss et al. col.; 9 June 1960, one specimen: UMML 30. 2699. - 2. Station 33. Europa Bay, St. John, Virgin Islands, shore to 10 ft.; John Randall, E. Iversen, and Hermann Kumpf col.; 16 February 1959, one specimen: UMML 30. 2700. Further distribution.-Coast of S. Paulo, Brazil (Marcus, 1955: 95). Biscayne Bay, Miami (id., 1960b: 140). Order ANASPIDEA Family APL YSIIDAE Subfamily Aplysiinae A plysia (V arria) cervina (Dall and Simpson, 190]) Material.-Upper Matecumbe Key, Monroe County, Florida; col. J. 452 Bulletin of Marine Science of the Gulf and Caribbean [12(3) Vallee, 21 March 1961, one specimen: UMML 30. 2703. Further Distribution.-Charleston, South Carolina; east coast of Vir- ginia Key; northern coast of Yucatan (Eales, 1960a: 299); Puerto Rico; Cura<;ao; Brazil, coast of Alagoas and 5. Paulo (Marcus, 1960b: 143). Remarks.-The slug was labeled in The Marine Laboratory, Univer- sity of Miami, and it came to us without radula. However, we think that the identification is correct, as the specimen shows scattered dark round spots on the sides, and the parapodia join low down over the root of the foot. Aplysia (Varria) dactylomela Rang, 1828 Reference.-Eales, 1960a: 307-310 and frontispiece. Material.-Europa Bay, 5t. John, Virgin Islands, Tony Chess col.; 20 April 1960, one specimen: UMML 30. 2704. Further distribution.-Worldwide in warm seas. Subfamily Dolabriferinae Dolabrifera dolabrifera (Rang, 1828) Material.-l. Triumph Reef, Dade County, Florida; Gilbert L. Voss et al. col.; 9 June 1960; one specimen: UMML 30. 2705 - 2. Haul- over Bay and Lesser Lameshur Bay, St. John, Virgin Islands, 1-5 ft.; col. Gilbert L. Voss, Hermann Kumpf, and Robert Work; 24 and 25 January and 19 June 1959, a total of ten specimens: UMML 30. 2706 - 30. 2709. Further distribution.-Circum-tropical and circum-sub-tropical (En- gel, 1936a: 42-43). Recently found on the coast of Brazil (Marcus, 1958: 57), but not recorded yet from the warm-water zone of western America, where another species with a widely different shell occurs on the coast of Nicaragua (Pilsbry, 1896: 124). The record from Greenland maintained in Pruvot-Fol's synopsis (1954a: 108) is almost certainly an error (Eales, 1944: 17, note). Remarks.-In the specimens from St. John the shell is typical in its angular shape with button-like callous spire (Engel, 1927: Fig. 7). The largest animals are, in preservation, 33 mm long, 22 mm broad, and 12 mm high. The radula of a slug 33 mm long had 43 rows with 116 lateral teeth in the half-row; the cusps are narrower than those of Engel's Figure 8 (1927: 96). The penial armature is weak in comparison with Eales' material from the Indian Ocean (1944: Fig. 10) and, as in Pruvot-Fol's 1962] Marcus & Marcus: Opisthobranchs 453 material from Tahiti (1954b: Fig. 14), consists of only one row of spines on the tiny male organ, and some spinous warts on the collar. The 22 mm long animal from Florida looks like a Dolabrifera, as it is broadest and highest about a quarter of the body length from the posterior end. Also the dorsal slit lies in the posterior fourth. Mandibular pegs, palatal plates, and radula agree with the corresponding organs of our material from 81. John. The radula contains about 40 rows. The smaller number, 105, of lateral teeth corresponds to the smaller size. The breadth of the cusps is similar to Eales' Figure 9 A (1944: 7). The male armature consists of a few spine- bearing warts on the collar; the penis itself is without spines. But as the spines are poorly developed also in the material from S1. John, we do not attribute systematic value to this character. In Petalifera petalifera (Rang, 1828) the spines of the penis are known to be variable (Engel, 1936a: 51), and Phyllaplysia zostericola was described both without (McCauley, 1960: 551, 573) and with spines (Marcus, 1961a: 11). The slug from Triumph Reef has no shell nor mantle foramen, but the mantle is completely dosed without vestiges of a loss of the shell. On account of this character we considered assigning the specimen to the genus Phyllaplysia, as Engel (1936c: 209) did with the Dolabrifera-shaped A clesia varicolor Bergh (1905: 21) from the Kei Islands. That species has 45 lateral teeth in the half-row of the radula and therefore remains within the known limits for Phyllaplysia (maximum: 53 in Ph. zostericola). For the present slug we prefer to presume a malformation. Such are not rare in retrograding organs (Marcus, 1957c: 56) as are the shells in the Anaspidea; Engel (1936a: 41) and Pruvot-Fol (1945a: 106, note 3) mention them in Dolabrifera. The skin of our Florida specimen agrees with Pruvot- Fat's description (I 954b: 9. Fig. 13). Petalifera ramosa Baba, 1959 Figures 1-3 Synonym.-Petalifera habei Eales, 1960 (1960b: 12ff., 112) Material.-2 mi. SSW of Alligator Reef light, Monroe County, Flo- rida; depth 120-150'; 19 August 1961, one sp.ecimen: UMML 30. 2710. Further distribution.-Tomioka, Amakusa Bay, southern Japan, from low tide mark to a few meters in depth; Misaki, Sagami Bay, Middle Japan; in both localities on Zostera marina. 454 Bulletin of Marine Science of the Gutf and Caribbean [12(3) Description.-The specimen is 21 mm long, 14 mm broad, and 8 mm high; it is broadest behind. The head is broad, not set off from the body; the tail is contracted. The convex upper side is separated from the flattened underside by well defined borders. The foot extends far forwards, nearly to the mouth, and the sole takes up about one half of the under surface; nearly one quarter of the breadth on either side is occupied by strong longitudinal muscles. The anterior border of the foot is bilabiate, its hind end pointed, probably due to contraction. The diaphanous back is beset with flat warts or dense disks, the retracted papillae. These occur also on head, tentacles and rhino- phares, extending onto the underside of the head backwards to the elliptical oral lobes. Some black and brown blotches are preserved on the posterior half of the back. The tentacles have truncated ends with short slits. The 3 mm long rhinophor.es, which are narrowed at their bases, stand 2 mm apart from one another. One mm farther outwards are the eyes, behind the rhinophores in the present specimen. The dorsal slit lies on the right side in the posterior half of the body; it begins 12 mm behind the anterior end and is 6 mm long. In the present animal the left parapodium lies uppermost, then fol-

~ 1

FIGURES 1-3. Petali/era ramosa Baba. 1, elements of jaw; 2, radular teeth; 3, palatal teeth. 1962] Marcus & Marcus: Opisthobranchs 455 lows the right border of the mantle with the shell and the right parapodium. The mantle foramen is wide; the thin shell is broad and circular in front, prolonged behind as in Baba's figure (1959: Fig. 1 B). In our animal the apex is broken. Behind the mantle roof the anal sipho projects. Within the mantle cavity the genital aperture, the gill, and the simple opaline gland (character of the subfamily) are visible without dissection. The seminal groove with a high left wall runs to the right tentacle. The elements of the jaws (Fig. 1) are hollow structures flattened against each other, those near the margins of the mandibular plates with fringed free edges like ctenoid scales. The radula (Fig. 2) contains 27 rows with 36-38 lateral teeth in a half-row. The rhachidian tooth has an excavated plate and three denticles on either side of the median cusp, compared with two in the Japanese specimens. The lateral teeth have up to six inner and four outer denticles, the Japanese material up to four inner and five outer ones. Only the very long outermost lateral plates are distinctly bifid at their ends; the others are faintly bifid or end with a single point. The penis sheath is unarmed, the penis proper has a row of five spines, and the collar two spiny warts. Discussion.-The description aims to justify the zoogeographically strange determination. In order to preserve the present specimen as far as possible, its alimentary tract and reproductive organs were not dissected. Baba and Eales figured the living and preserved animal and its parts, with the exception of the components of the mandi- bles which we add. The only Petalifera hitherto known from warm Atlantic waters was Petalifera petalifera f. bonairei Engel, (1936a: 44-45) which differs from P. ramosa by oral lobes and radula. One can expect that the present species as well as the following one may in the future be found in warmer waters on the Pacific coast of America, where the opisthobranchs are less well known than in temperate localities such as Monterey Bay, Dillon Beach, and Van- couver. Subfamily Notarchinae Notarchus Cuvier, 1817 (emend. Bergh, 1902: 344) When Eales' terse key (1944: 19) for classification of the anaspi- dean (aplysiacean) subfamilies and genera is used, two facts should be considered. Notarchus, in its former wider sense of Pilsbry (1896: 456 Bulletin of Marine Science of the Gulf and Caribbean [12(3) 135) and Hagg's bibliography (1904: 7-13), has been substituted by Engel's (1929: 193, 202) and Eales and Engel's (1935: 281) definitions of the genus. To the latter only the section Notarchus of Thiele's treatise (1931: 398) corresponds. Secondly, Eales and Eng- el's (1935: 281) warning of the variability of all Aplysiidae must be remembered. The processes (villi) of the back are completely retractile in Notarchus and so, at first sight, the determination of the nu-

FIGURES 4-6. Notarchus punctatus armatus Baba. 4, radular teeth; 5, male copulatory organ, opened; 6, genital organs. 1962] Marcus & Marcus: Opisthobranchs 457 merous, quite smooth slugs of the present material met with an obstacle in the above-mentioned key. According to Engel's revision of older material and descriptions (1929; 1936a: 57, 66; 1936b) there are two species of Notarchus, differing in radula and male copulatory organ. These are N. indicus Schweigger, 1820, the type-species from the Indian and western Pa- cific Oceans, and N. punctatus Philippi, 1836, from the Mediterra- nean. The radula of indicus has long lateral teeth; at least the last third of each row has long, scythe-like teeth (Engel, 1936b: 118); the penis is unarmed. In punctatus the lateral teeth are shorter and broader, the longest ones narrow leaf-like (Vayssiere, 1885: Figs. 84, 85; Engel, 1929: Fig. 4); and the penis and its collar are covered with spines. The one-sided dentic1es of the lateral teeth in indicus, developed on both edges in punctatus, cannot be maintained as dif- ferential characteristics, in view of Eales' (1944: 12) specimen of indicus whose laterals are serrate on both edges. After 1936, Notarchus indicus armatus Baba, (1938: 4; 1949: 28, 127) was found. Its spiny penis separates it from indicus. On the other hand the spines are not raised on warts as in punctatus (Engel, 1936b: Fig. 3 D), and the lateral teeth (Baba, 1938: Fig. 2 e) are rather scythe-shaped than long leaves. Baba did not compare his subspecies with punctatus and related it to indicus probably for zoogeographic reasons. But morphology must prevail in the taxonomy of these little-known animals and, as the radula is less disjunctive (Engel, 1936b: 114; Eales, 1944: 12) than the penis in species of Notarchus we consider Baba's form as a subspecies of punctatus. All essential characters given by Baba agree with the present material from Florida, so we include it in his subspecies armatus. In order to make a recognition of further systematic units possible, our description, which follows Eales' pattern (1944: 1), refers exclusively to the present material and stresses some slight differences from that of Baba. Notarchus punctatus armatus Baba, 1938 Figures 4-6 Material.-D de S 360. 4 mi. off Islamorada, Monroe County, Flo- rida; 40 fms.; D. de Sylva, M. Manning, WaIter A. Starck, II; 20 August 1961,27 specimens: UMML 30.2711. Further distribution.-Middle Japan, southwestern coast of the Kii Peninsula; Sagami Bay, 8-10 m. 458 Bulletin of Marine Science of the Gulf and Caribbean [12(3) Description.-The snails all have their heads tucked into the body, as is often the case in preserved N otarchus (Eales, 1944: 18). The skin is soft and smooth. The length is up to 32 mm, the height 24 mm, the breadth 19 mm. The sole contracted in transverse direction is about 25 mm long. 2 mm broad; the head about 10 mm long. Tenta- cles, rhinophores and muzzle are completely withdrawn. The dorsal slit is 8 mm long. There is no tail. The color is olive, with numerous black spots up to 2 mm in diameter, and small light dots, evidently around openings of glands. Tentacles, rhinophores, muzzle and seminal groove have no black spots; the sale is yellowish. The black eyes lie a little in front of the rolled rhinophores. The more consistent centers of larger light blotches are probably retracted villi. Some dark pigment is preserved in folds of the skin, as generally in aplysiids. The lining of the mantle cavity is olive-colored like the outside. The left slightly dotted parapodium overlaps the right one. There is no shell nor mantle foramen. The gill is pigmented in the middle of its upper side. A small pallial shield projects in front of it. The shield lodges the purple gland, recognizable by numerous separate black dots, if the gland .cells are not emptied. To the left of the purple gland lies the long kidney. Under the gill, on the afferent branchial blood sinus, lies the button-shaped osphradium surrounded by a circular thickening as in punctatus (Pelseneer, 1894: Fig. 81). The genital aperture lies far in front on the floor of the large mantle cavity. To the right of it the diffuse opaline gland opens. The jaws are broader than long; their pegs stand in 30-35 not quite regular transvers.e series. Each peg is striped transversely due to successive secretion of its cuticular layers; the free edges are smooth and become serrulate by wear. The very numerous and slender palatal hooks are smooth, not striped. The radula (Fig. 4) has 30-33 rows of 36-38 teeth in each half-row. These numbers exceed Baba's of 26 s.eries with up to 33 teeth in a half-row, but the difference is without systematic value. The trapezoidal central tooth has three (two in Baba's specimens) lateral denticles on each side of the median cusp. Minute secondary dentic1es may raise the number of lateral dentic1es to five in our material. The cusps of the lateral teeth increase in length outwards, while their bases remain the same. The 28th and the seven following teeth have cusps of about 0.3 mm. These teeth as well as the preceding ones are serrate on both edges. The number of serrulations, up to six outer and seven inner ones, 1962] Marcus & Marcus: Opisthobranchs 459 corresponds to Baba's drawings (1938: Fig. 2; 1949: Fig. 13), but not to his text which indicates two to three denticles. The three outermost teeth of the present specimens are smaller and are lost in older rows. The five outermost lateral teeth may have denticles on one side (the inner or, rarely, the outer), or none at all. The long salivary glands are fastened to the anterior region of the gizzard, whose silky outside is due to a close layer of annular muscles. The anterior part of the gizzard contains 18 large and small masticatory teeth. In the posterior part there are two to four irregular rows of soft, blunt bosses with brown tips. Anterior and posterior digestive glands open into the gut behind the gizzard. The intestine winds backwards beyond the gonad, whence the rectum runs forwards. The intestine is imbedded in the surface of the digestive gland. The rectum lies in a cutaneous fold of the right side; the anal opening is steJlate. A caecum does not occur in our specimens, nor in N. indicus (Eales, 1944: 12). For punctatus from the Medi- terranean the texts of Vayssiere (1885: 86) and Bergh (1902: 347) and the figure of Guiart (1901: Fig. 44) do not indicate a caecum; Mazzarelli (1893, quoted from Hoffmann, 1939: 1114) indicated it, but we cannot evaluate the determination. The penial sheath (praeputium) of N. punctatus armatus (Fig. 5) consists of two sacs, one behind the other. At rest the inner, basal one lodges the spinous penis (p); the outer one has no spines, and its walls form two unequal muscular cushions (er, rc). The same applies to punctatus punctatus (Pruvot-Fol, 1930: Fig. 6; Engel, 1936b: Fig. 3), but the penial armatur,e of Baba's (1938: Figs. 2 E, F) and our armatus is weaker. Spines on the collar (c) around the penial root are developed in our armatus and typical punctatus (Bergh, 1902: 349; Engel, 1936b). Probably Baba did not pull out the organ far enough to see the collar. Also in Vayssiere's figure (1885: Fig. 88), repeated twice subsequently (1913: PI. 17, Fig. 8; 1930: Fig. 8), there is no collar. A longitudinal, spine-free zone occurs in Engel's and our material. Engel (1936b: 116), and allus- ively also Bergh (1902: 349, PI. 28, Figs. 30, 31), described the spines sitting on warts which are absent in Baba's and our armatus. It is, however, possible that these warts are retractile, as Vayssiere's and Pruvot-Fol's figures do not show them. The shape of the penis varies; it is compressed in one direction or the other. The racemose gonad lies around and behind the digestive gland. The following little hermaphrodite duct or spermoviduct (Fig. 6, h) 460 Bulletin of Marine Science of the Gulf and Caribbean [12(3) loops around the canal of the spermatocyst. Farther in front it bifurcates. The bifurcation is the fertilization chamber. The sperms pass along the seminal groove in the large hermaphrodite duct to the genital aperture, whence the groove (sr) courses through the dorsal slit and along the neck to the penis. From the fertilization chamber the eggs pass to the brown, hard albumen gland (a) with numerous foliaceous folds. The next section of the female duct is the whitish, convoluted or winding gland (w),' a thin coiled organ, followed by the transparent mucus gland (m) whose folds are radiate. The mucus gland describes two circles around the albumen gland, communicates with the fertilization chamber and thereby with the large hermaphrodite duct. The large hermaphrodite duct contains the seminal groove overlain by a fold on one side and by the oviduct on the other, the latter with oblique folds. Between them are two high longitudinal glandular folds which continue forward to the level of the spermathecal duct. The duct of the spermatocyst (y) leaves the large hermaphrodite duct farther entally, near its beginning. The vaginal part of the hermaphrodite duct is characterized by longitudinal folds. The shape of the sperm reservatories varies according to their contents. The entrance of the duct of the spermatheca (t) is marked by a pouch (b) filled with zigzag folds, corresponding with the clustered gland of Aplysia. The outermost section of the large hermaphrodite duct is longitudinally folded. Discussion.-There are three figures of the genital ducts of N. punctatus punctatus: those of Guiart (190 I: Fig. 95), Bergh (1902: PI. 28, Fig. 26) and Pruvot-Fol (1960: Fig. 20 H). The second and most complete one agrees with ours of punctatus armatus. The genital ducts of N. indicus have not yet been illustrated; Pruvot- Fol's Figure 20 H is Vayssiere's Notarchus indicus (1906: Fig. 9), but his species was recognized (Engel, 1936a: 57, 66; 1936b: 119) as Stylocheilus longicauda (Quay et Gaimard, 1824). Of the four genera of the Notarchinae, the genital ducts are known in Notarchus, Stylocheilus (Vayssiere, 1906) and Bursatella, of which B. leachii lacinulata Gould, 1852, was examined for this discussion. The ducts of Barnardaclesia are not known; those drawn by Bergh (1907: PI. 2, Fig. 2) belong to B ursatella leachii Blainville, 1817 (Eales and Engel, 1935: 300; Eales, 1952: 71). In the known genera the mucus gland forms one loop around the anterior and one 1962] Marcus & Marcus: Opisthobranchs 461 around the posterior surface of the sac-shaped albumen gland, while in Aplysia both glands together run in several parallel coils (Marcus, 1959a: PIs. 1-4).

Order ASCOGLOSSA Suborder ELYSIACEA Family ELYSIIDAE Tridachia crispata March, 1863 Figures 7, 8 Principal references.-March, 1863: 40; Bergh, 1872: 191-198; Yonge and Nicholas, 1940: 289-301; Marcus, 1960b: 153-159. Material.-l. Reef patch north of Pacific Reef, Dade County, Flo- rida; Gilbert L. Voss et al. col.; 6 June 1960, one specimen: UMML 30.2712. - 2. Bay side, Crawl Key, Monroe County, Florida; C. R. Robins and Reeve M. Bailey family col.; July 1961, numerous specimens: UMML 30. 2713.-3. Ocean side, Key Largo, Monroe County, Florida; J. Vallee col.; 10 April 1961, one specimen UMML 30. 2714. - 4. Stations 33 and 34. Europa Bay, shore to 10 ft., and cave in east side of Europa Bay, depth 4 ft., St. John, Virgin Islands; John Randall, E. Iversen, and Hermann Kumpf col.; 16 February 1959, a total of eight specimens: UMML 30.2701,2702.-5. SJHK 59-76. S. shore, Reef Bay, St. John, V. I.; poison station at base of bay in rubble and grass area, 1-3 ft.; Hermann Kumpf col.; 14 July 1959, one specimen: UMML 30.2715.-6. WAS Carib 16. 200 yards S. of Cay Bohel, Turneffe Is., British Honduras, depth 12 ft.; Walter A. Starck, II col.; 30 June 1961, one specimen: UMML 30. 2716. Further distribution.-Dry Tortugas Keys; Antilles; Venezuela; Cura- c;ao. Remarks.-The specimens from locality 2 attain 50 mm in length, 38 in breadth. Their green color is preserved; the tail is lighter. White spots and stipples occur on the whole upper side and on the underside of the parapodia. The lips and the rhinophores are white. A light blue streak runs along the edge of the parapodia. The margin of the parapodia contains, about 0.2 mm from the edge, a band of zooxanthellae. Their color had disappeared, and they were studied in sections. Beside smaller algae, 10-20 JL in diameter, with central nucleus and peripheral chloroplasts, agreeing with those of Yonge and Nicholas' Figure 9, there are 25-60 JL big ones whose nucleus 462 Bulletin of Marine Science of the Gulf and Caribbean [12(3) lies within the thick wall. The latter algae are similar to those found in the turbellarian Amphiscolops sargassi (Marcus, 1950: 19); their center is occupied by a vacuole containing a voluminous pyrenoid. Like those studied by Yonge and Nicholas (1931: 141), they have no well defined cellulose wall. The oesophagus is of different length in slugs of similar size from one and the same lot. In one case we found the oesophageal section (0) between nerve ring (n) and muscular pouch (sc) nearly straight (Fig. 8); in another it was much longer and curved V-wise (Fig. 7).

FIGURES 7-8. rridachia crispata Morch. 7, alimentary tract of specimen with long oesophagus (0); 8, same, with short oesophagus.

Discussion.-Slugs with a nearly straight oesophagus (Bergh, 1872: PI. 23, Fig. 11; Marcus, 1960b: Fig. 38) cannot be separated systematically from those with an oesophageal loop (Yonge and Nich- olas, 1940: Fig. 5). Our previous contrary opinion (Marcus, 1960b: 158) must be altered, because the length of the oesophagus varies individually. Consequently, the loop cannot have a special function, as Yonge and Nicholas assumed (1940: 297). Also the absence of zooxanthellae as in our first material is no systematic character. The orange or brownish color of these algae is the first of all color marks to disappear when slugs are preserved. All hitherto described Tridachia from the West Indies belong to one and the same species. The author of the genus is Deshayes (1857: ]42); the name of 1962] Marcus & Marcus: Opisthobranchs 463 the species must be crispata (Engel, 1927: 115). Deshayes described the characteristic shape of the parapodia, not their color. He wrote: "we propose the name Tridachia for the genus, and for the species that of Mr. Schramm to whom the discovery is due." Hence "Tri- dachia schrammi, Desh. (Journ. de Conch., 1857, p. 141)" as March (1863: 41) wrote, does not,exist, though Pruvot-Fol (1946: 42) uses it; Tridachia schrammi March, 1863, is a nomen nudum.

Order NOT ASPIDEA Suborder PLEUROBRANCHACEA Family PLEUROBRANCHIDAE Subfamily Pleurobranchinae Berthellina quadridens (March, 1863) Figures 9-13 Rejerences.-March, 1863: 29; Bergh, 1898: 136, PI. 10, Figs. 12-19. Material.-l. SJHK 58-31. Greater Lameshur Bay, off Yawzi Pt. St. John, Virgin Islands; 30'; John Randall, L. and S. Thomas col.; 21 December 1958, three specimens: UMML 30.2717. - 2. Station 33. Europa Bay, St. John, V. 1., shore to 10 ft.; J. Randall, E. Iversen, and H. Kumpf col.; 16 February 1959, three specimens: UMML 30. 2718. Further distribution.-St. Thomas, Virgin Islands. Description.-The animals are 20-25 mm long, 14-20 mm broad, and 12-15 mm high. The mantle does not quite reach the edge of the sole. The mantle border of the preserved specimens is rolled in. The color is whitish; thickened knots in the dorsal epidermis are glands. The white shell (Fig. 9) lies far behind; its size is not correlated with that of the animal. In the larger specimens from Lameshur Bay (locality 1) a shell 5 mm long and 3 mm broad was found; in the smaller ones from Europa Bay (locality 2) the shell measured 6.2 mm in length, 3.6 mm in breadth. The yellowish peri- ostracum already mentioned by Bergh (1898: 136) is distinct. Spicules were not found. The anterior border of the foot is bilabiate, the sale up to 15 mm broad, the tail pointed, without caudal gland. The velum is straight, 10 mm broad. The rhinophores are long, thickened at the base, and rolled along their whole length. The gill is about 10 mm long and bears some 20 pinnules on .each side of the smooth rhachis. The 464 Bulletin of Marine Science of the Gulf and Caribbean [12(3) anus lies behind the end of the branchial membrane which leaves about six pinnules free. The cusps of the mandibular platelets (Fig. 10) range from one to eight. Sometimes there are two equal or unequal points, or a principal point flanked symmetrically or asymmetrically by two minor points. Their number and breadth varies considerably; five points are frequent. All platelets of Fig. 10 are from one animal from Lame- shur Bay, except the two uppermost ones which are of a slug from Europa Bay. The articulation points of the platelets lie on very different levels as was stressed by Bergh (1898: 137). The radulae examined consist of 90 and 98 rows, and have about 300 teeth in the half-row. The teeth are up to 0.4 mm long, thus very tall, and end with curved hooks, or with nearly straight points as

9 II

12 13

FIGURES 9-13. Berthellina quadridens (Morch). 9, shell; 10, mandibular platelets of specimen from Lameshur Bay, the two at far left from specimen from Europa Bay; 11, radular teeth of specimen from Lameshur Bay; 12, same, Europa Bay; 13, outermost radular tooth of specimen from Europa Bay. 1962] Marcus & Marcus: Opisthobranchs 465 in the outer teeth of the animal from Lameshur Bay. Below the terminal hook there are one to four denticles (Fig. 11). The "quadridens" tooth of the original description (March, 1863: 29) with three denticles below the hook, the uppermost bigger, the two others smaller and of equal size, occurs, among other types of denticulation, in the examined specimen from Europa Bay (Fig. 12). The outermost tooth of this radula has a slightly bifid tip (Fig. 13). The reproductive organs are exactly as in B. amarillia (Mattox, 1953: Fig. 10). Near its origin from the hermaphrodite duct, the sperm duct has a prostate. A long tubular appendage, Mattox' "seminal vesicle," opens into the sperm duct approximately at its middle. The female system is remarkable by the absence of a fertilizing or uterine duct, i.e., a communication between the duct of the spermatocyst and the albumen gland. Hence for fertilization the sperms must descend the vagina, enter the nidamental opening, and rise into the albumen gland to meet the eggs. Discussion.-There are two more species of Berthe/lina from the same region, B. circularis (March, 1863: 31) from St. Thomas, Virgin Islands, and B. amarillia (Mattox, 1953: 110) from the southwestern shore of Puerto Rico, whose original generic position required correction (Marcus, 1957a: 21). For a comparison of the two species from St. Thomas, Bergh's re-examination (1898: 134-138) of the original material is important; Bergh inverted March's sequence in his text and maintained it in the figures. Of B. circular is a single specimen is known, and the figures (Bergh, 1898: PI. 10, Figs. 31-37) refer to mandibular platelets and radular teeth, the variability of which was stressed in our preceding description of quadridens. March's only indication of taxonomic value for circularis, ctenidium fixed along its total length and comprising 16 pinnules, has not been .confirmed by Bergh. He counted 20 pinnules on either side and stated that the last fifth of the gill is free as in quadridens. Bergh's indication of 130 rows in the radula of circularis may be compatible with our up to 98 rows, as his animal was bigger (38 mm). In quadridens Bergh could not count the rows, because the radula was fragile; he indicated about 70 rows. He found 200 teeth in circularis and 150 in quadridens, hence none of his counts of radular elements agrees with ours. Bergh described the denticulation of the innermost and outermost teeth of circularis (1898: 135, PI. 10, Figs. 34, 35) as stronger than in the middle of the half-row. 466 Bulletin of Marine Science of the Gulf and Caribbean [12(3) We found, on the contrary, the teeth in the middle with more, those on the inner and outer ,end of the half-row with fewer dentic1es in both of the radulae examined by us. Therefore we cannot consider circularis as a synonym of quadridens. We maintain amarillia as a separate species also. Even supposing partial decalcification of the spicules in quadridens, which Bergh drew 20 years after having received the specimens (1898: PI. 10, Fig. 13), they differ widely from those of amarillia (Mattox, 1953: PI. 10, Fig. 4). Moreov,er, amarillia has 180-190 rows of teeth with up to ten denticles below the terminal hook. Size of the shell and number of radular rows and teeth in each row generally increase with age and body size, but the length of preserved specimens has only an approximate value, because individuals of one and the same lot narcotized and preserved together may contract with quite different intensity. Exact comparative systematics should start with measurements of living slugs, at rest or creeping, but under the same conditions.

Pleurobranchus (Pleurobranchus) areolatus March, 1863 Figures 14, 15 Synonym.-Pleurobranchus (Susania) atlanticus Abbott, 1949: 73-78, PI. 5. Material.-l. Triumph Reef and upper Long Reef, Dade County, Florida; Gilbert L. Voss et al. col.; 9 June 1960, a total of three specimens: UMML 30.2722 and 30.2723.-2. SJHK 58-31. Greater Lameshur Bay, off Yawzi Pt., St. John, Virgin Islands, 30'; John Randall, L. and S. Thomas col.; 21 December 1958, one specimen: UMML 30. 2720.-3. SJHK 59-6. E. shore of Greater Lameshur Bay, St. John, V.I.; littoral and sublittoral rock area; Hermann Kumpf, Gilbert L. Voss, and C. Adams col.; 22 January 1959, two specimens: UMML 30. 2719.-4. Reef Bay, St. John, V. I.; depth 70'; inside lip of dead conch (Strombus gigas Linne, 1758); John Randall col.; 10 May 1960, three specimens: UMML 30. 2721. Further distribution.-Soldier Key. Biscayne Bay, and throughout the Florida Keys (Abbott, 1949: 76); St. Thomas, V. I. (March, 1863: 29); Barbados (Bergh, 1897: 111). Remarks.-Abbott (1949: 77) separated atlanticus from areolatus by different sculpture of the notum, and folds around the genital orifices much less developed in areolatus (see Bergh, 1897: Pi. 9, 1962] Marcus & Marcus: Opisthobranchs 467 Fig. 33). The latter character is difficult to evaluate in preserved specimens whose folds may be contracted or covered by the everted genital atria. The sculpture of the notum in a living slug, or well relaxed, preserved ones, should not be compared with material preserved without previous narcotization. The present specimens have tubercles of various sizes; one animal is nearly smooth. The areae around the tubercles are most frequently separated from each other by dark lines in the present material, white ones in Bergh's specimens earlier examined by March. The shell in our material from S1. John has a spire of 1.5 whorls like Abbott's from Florida. One shell from St. John is chestnut brown as was March's; another is yellowish white with a faint rosy tint on the outer surface as reported by Abbott, but with a brown interior. Our shells from Florida are decalcified, and the conchinous constituent of the shell is preserved in folded, shapeless, condition. Our shells from the Virgin Islands have an elongate calcareous layer as described by March and drawn by Abbott. The broad conchinous border (Abbott, 1949: Fig. 8, HY) occurs in our shells also (Fig. 14); it was not drawn by Bergh (1897: PI. 9, Fig. 31). What appears as the "flaring last whorl" in Bergh's shell is pre- sumably brought about by a part of the last whorl having been broken off. If the piece outside the dashed line in our Fig. 14 were broken off, the outline of the shell would resemble Bergh's figure. In the latter, the growth lines do not encircle the margin but end abruptly on it. The radula of Bergh's specimens consisted of 76-80 rows, that of Abbott's of 75, and ours of 80 (Triumph and Long Reef, Florida) and 94 rows (St. John, Virgin Islands). Bergh's indication of 120 teeth evidently refers to the half-row. Abbott found 190 teeth in the half-row, we 180 (Florida) and 200 (St. John). 15

FlORES 14-15. Pleurobranchus areolatus Morch. 14, shell, upper surface; 15, shell, lower surface. 468 Bulletin of Marine Science of the Gulf and Caribbean [12(3) Though Abbott's description and figures remain indispensable to our knowledge of the species, its correct name is, in our opinion, that given by March. Discussion.-As the type-species of Susania Gray, 1857 (Pleuro- branchus testudinarius Cantraine, 1840), has a posterior shell (Bergh, 1897: 84), the present species cannot be allotted to this genus (White, 1946: 52) which Bergh (1897: 63-64), Odhner (1926: 21) and Pruvot-Fol (1954a: 222) do not separate from Oscanius Leach, 1847. P. areolatus with an anterior shell belongs to Pleurobranchus, or to Pleurobranchus (Pleurobranchus) if Oscanius is considered a subgenus of Pleurobranchus as in Odhner's system. Susania gardineri White (1952: 106) from Dry Tortugas also has an anterior shell, thus belonging to Pleurobranchus, and is probably P. areolatus. The number of 75 radular rows agrees with Abbott's indication, and so does that of 176-186 teeth in a half-row. The partly decalcified shell (Fig. 3 A) does not permit specific separation from areolatus. The depth of the sinus in the anterior mantle border, which White considers a character of Susania (1946: 52; 1952: 107), "can be changed at will by the animal" (Abbott, 1949: 74) and varies according to contraction in preserved specimens. The relatively short ctenidium with only 18 pinnules could, perhaps, isolate gardineri, whose body is up to 59 mm long preserved. However, the number of pinnules varies widely in areolatus; March indicated about 16, Abbott found 20-22, Bergh 23-26, and we up to 27. Nothing can be said about Pleurobranchus reesi White (1952: 107) from Bird Key Reef, Florida, because the position of the shell is not indicated. Order NUDIBRANCHIA Suborder DORIDACEA Section EUDORIDACEA Tribe HEXABRANCHIATA Family HEXABRANCHIDAE Hexabranchus morsomus, spec. nov. Figures 16, 17 Material.-Harbor of Spanish Town, Virgin Gorda, British Virgin Islands; Tony Chess col.; 4 December 1959, one specimen. Noted swimming off bottom by body undulations. Bright red and cream. Description.-The length is 30 mm, the breadth 17 mm, the height 3 mm. The color is not preserved, the body is whitish with brown 1962] Marcus & Marcus: Opisthobranchs 469 viscera shining through the skin. The latter is smooth without tubercles or spicules. The rim of the notum is broad, thin, and frilled. The foot is narrower than the notum and projects with a 5 mm long tail; the pedal margin is folded. The auriculate, flap-like tentacles have crenate upper borders. The rhinophores have about 30 leaves, smooth shafts, and pockets with smooth rims. The six tripinnate gills form a circle in whose center the wide anal opening lies, and in front of it the renal pore.

FIGURES 16-17. Hexabranchus morsomus, sp. nov. 16, middle of row of radula; 17, reproductive organs.

The mouth projects as a flattened cone showing the labial disk covered by a cuticle with slight radial ribs. The genital atrium lies 10 mm behind the anterior end. It is everted so that two openings can be seen. One on a papilla is the common orifice of male duct and vagina; the other, more ventral, one is the nidamental opening. The radula is 5.8 mm long and 5 mm broad. It consists of 40 rows with 90 teeth in the half-row. The rhachis bears a small, triangular plate, a rudimentary tooth (Fig. 16). The ten following inner teeth are 0.1 mm high. Toward the middle of the half-row the teeth attain a height of about 0.18 mm and have cusps 0.12 mm long; the outer- 470 Bulletin of Marine Science of the Gulf and Caribbean [J2(3) most teeth again decrease. The oesophagus has longitudinal folds. The hermaphrodite duct (Fig. 17, h) forms an ample ampulla (am), then narrows and enters the small albumen gland (a), where it bifurcates. The male duct emerges from the albumen gland and begins as a thick prostate (q). The following section (e) is muscular, the next glandular. The outermost section is the long cuticularized copulatory organ, an acrembolic penis (p). The oviduct goes from the albumen gland to the correspondingly small mucus gland (m). The nidamental duct (ni) is wide and thin- walled. The muscular vagina (v) begins beside the penis and dilates into an ample spermath.eca (t) lying dorsal to the genital mass. Beside the entrance of the vagina the insemination or uterine duct leaves the spermatheca. The spermatocyst (y) is a long, curved sac and communicates with the albumen gland by a short ,continuation of the insemination duct (f). In order to leave as much as possible of the remarkable specimen we dissected only the indispensable organs. Holotype.-The slug and two slides (radula and reproductive organs), UMML. 30. 2696. Discussion.-The Hexabranchidae have no mandible, hence belong to the Eudoridacea (Odhner, 1934: 233). Their gills are contractile, but not retractile into a permanent pocket as in the Cryptobranchiata. Their broad notum with free margin and the numerous uniform radular teeth separate them from the Phanerobranchiata. These facts were aIr,eady stressed by Eliot (191 Oa: 64, note 3) and Hoffmann (1940: 49) and lead us to establish a special tribe, Hexabranchiata. The Dendrodorididae and the Phyllidiidae, however, which lack jaws and radula, constitute a special Section, Porostomata Bergh, 1876, coordinate with Gnathodoridacea and Eudoridacea. While the Poro- stomata are highly specialized, the Hexabranchiata have primitive as well as advanced characters. The radula is primitive in the great number of undifferentiated teeth and a rhachis with a tooth-like thickening in the present species. The genital organs combine a primitive acrembolic efferent duct with the more specialized prostate, and a semiserialconnection (Odhner, 1926: 51) of the female seminal reservatories, a type intermediate between vaginal and serial. The nervous system of the Hexabranchiata is highly concentrated (Eales, 1938: 94). This agrees with their lively swimming activity, even in rough water (Risbec, 1928: 116). 1962] Marcus & Marcus: Opisthobranchs 471 The specific divisions of Hexabranchus are extremely doubtful (Eliot, 191 Ob: 419), perhaps at least in part due to the quasi-pelagic life of these slugs which are frequently found swimimng at some distance from the land. More than 20 species were described, all from tropical or subtropical regions of the Indo-Pacific. The Red Sea and the east coast of Africa southward to Inhaca, 26° S (Macnae and Kalk, 1958: 45, 128) are the western limit, and the Hawaiian Islands (Gould, 1852; Souleyet et Eydoux, 1852; Ostergaard, 1955: 128- 133) the eastern. The northernmost occurrence is at the southwest shore of the Kii Peninsula, 34° N, Middle Japan (Baba, 1938: 1,2), the southernmost is the coast of New South Wales (Allan, 1950: 223). Many species were described without examination of the radula. The number of gills is in most cases six, sometimes seven or eight, and exceptionally five. The living slugs are frequently red and yellowish, colors which Eliot (191 Oa: 23-24) considered warning wh~n the red margin of the notum is displayed, protective when it is folded over the back. Several species were based on preserved specimens whose colors had in part or completely faded out. It is highly probable that all the commoner forms are color varieties of a single species (Bergh, 1900: 225; Eliot, 1909: 83;id., 1910b: 419;Pruvot-Fol, 1943: 75). Even the name for this species, Hexabranchus lacer (Cuvier, 1804) or more probably H. marginatus (Quoy et Gaimard, 1832), seems not to be definitiv,ely settled (Bergh, 1905: 89 and note 3). From Hagg's bibliography (1904: 16), where March's paper (1863) is quoted, it appears as if Hexabranchus was already known from the West Indies. However, March was aware that Gray's Hexa- branch us is different from Hexabranchus Ehrenberg, 1831, and gave it the name Rhacodoris. Bergh (1879b: 45) recognized that March's Rhacodoris krebsii belongs to the genus of the Porostomata that is now called Dendrodoris Ehrenberg, 1831. The present species is the first Hexabranchus from the Atlantic Ocean. It differs from all other species with known radula by the rudimentary rhachidian tooth. This plate-shaped thickening would not have escaped Bergh and Eliot who were accurate in the analyses of the radulae. We stress .that the rudimentary single median plate is unpaired and uniformly present in all rows; it cannot be confounded with the several reduced internal teeth of H. praetextus Ehrenberg, 1831 (Vayssiere, 1912: Fig. 113). By comparative study of the literatur,e (e.g. Bergh, 1905: 89, 90, notes) we found the numbers of radular rows and teeth relatively high for this small slug. 472 Bulletin of Marine Science of the Gulf and Caribbean [12(3) Section POROSTOMATA Family DENDRODORIDIDAE Doriospsilla areolata Bergh, 1880 Figure 18 Principal references.-Bergh, 1880: 316 fl.; 1896: 454 fl.; Vayssiere, 1901: 50; 1919: 83; Nobre, 1938-40: 46; Pruvot-Fol, 1951: 39; 1952: 411 fl.; 1953: 90; 1954a: 336. Material.--SJHK 59-6. E. shore of Greater Lameshur Bay, St. John, Virgin Islands; littoral and sublittoral rock area; Hermann Kumpf, Gilbert L. Voss, and C. Adams col.; 22 January 1959, one specimen: UMML 30. 2724. Further distribution.-Adriatic Sea; French Mediterranean coast; East Atlantic coast, southernmost France, Portugal, Morocco; Cape Verde Islands (Eliot, 1906b: 148). Description.-The slug is 16 mm long, 8 mm broad, and 5 mm high. The color is uniformly brownish. The notum bears round tubercles, up to 1 mm in diameter. The larger ones lie on either side of the middle, and between them and around the borders there are smaller warts. Vayssiere's figure of an unnamed variety (1919: PI. 5, Fig. 34) and Pruvot-Fol's photographs (1951: Fig. 21) correspond well to the aspect of the present specimen. Numerous, in part rather thick, spicules lie in the connective tissue of notum and hyponotum. The position of the spicules, generally perpendicular to one another but parallel to the skin, does not agree with Bergh's description (1896: 457). The notal border is soft, nearly without spicules, curled upward, and slightly folded. The spicules do not project on the surface of the tubercles. The foot is narrower than the notum, straight in front, and pointed behind. The rhinophores have about 20 foliations which are too soft to be counted exactly. The borders of the rhinophorial pockets are smooth. The genital openings lie 5 mm behind the anterior end. The conspicuous anal papilla is situated to the left of four tripinnate gills. The por,e-like mouth is flanked by the minute tentacles. It leads into a vestibule or oral cavity (Fig. 18, j) whose thick wall contains glands and muscles. Its fundus is fastened to the body wall by two retractor muscles (r). The bulbar tip of the pharynx, Bergh's "Schlund- kegel," projects into the vestibule. To the right of the pharynx lies the blood gland (co), whose outlines are smooth. The section of the tubular gut in front of the nerve ring (n), the pharynx (u), is 1962] Marcus & Marcus: Opisthobranchs 473 thinner than that behind it. The buccal ganglia (cc) are apposed to the pedal ganglia. The oesophagus (0) is glandular; it ends with a muscular section (iz), the "renflement spherique" or "sorte de gesier" ofVayssiere (1901: 52, 125, PI. 3, Fig. 19, g; 1902: 235). The annular fibres of this section function as sphincter to the entrance of the stomach (s). Occlusion of the cardia may help the anterior gut to suck in the loose tissue of sponges. Over the posterior oesophagus lies a secretory gland (ze) coated with muscles and connected with the gut by a short and wide duct (in). This yellowish duct agrees histologically with the gland; its opening into the gut was not found in the sections; probably it was tom during dissection. Besides the unpaired gland there are no other glands joined to the anterior gut. Discussion.-For a better understanding of our single specimen and of Bergh's and Pruvot-Fol's papers cited above, we reexamined the larger species Dendrodoris atropos (Bergh, 1879), of which we have well preserved specimens from the coast of S. Paulo (Fig. 19). Its

FIGURE 18. Doriopsilla area/ata Bergh; anterior part of alimentary tract. FIGURE 19. Dendrodaris atropos (Bergh); anterior part of alimentary tract of specimen from Sao Paulo. 474 Bulletin of Marine Science of the Gulf and Caribbean [12(3) oral vestibule (j) receives the long duct (un) of a bilobed ptyaline gland (g). The boundary between the pharynx (u) and the glandular oesophagus (ue) coincides with the position of the buccal ganglia (cc) and the small, sessile salivary glands (sa). A voluminous blood gland (co), a ductless lymphatic organ, is connected with the oesophagus by several vessels (Bergh, 1879: 60). The passage of the oesophagus into the stomach (s) is characterized by a strong sphincter (iz). In Doriopsilla areolata (Fig. 18) the vestibule with its retractors and the projection of the pharynx into it are the same as in Dendro- doris atropos. There is, however, no ptyaline gland and duct discharging into the vestibule. Pruvot-Fol's assertion (1951: 39, and else- where) that ptyaline glands described for Doriopsilla are really blood glands is confirmed by our sections. D. leia and D. pharpa Marcus (1961b: 145, 146) also have no ptyaline glands. Bergh, it is true, described a ptyaline gland in three of the four species of Doriopsilla studied, D. areolata. D. pallida, and D. capensis. This may be due to an unusual location of the blood gland. Generally, it lies dorsal to the nerve ring (e.g., Pruvot-Fol, 1953: Fig. 35), but in our specimen it lay to the right of the central nervous system. One of the retractor muscles of the vestibule can easily he held for a ptyaline duct, if the organ is not sectioned with the microtome. The theoretical boundary between pharynx and oesophagus may be defined by the position of the buccal ganglia (Bergh, 1896: 457), but not by the salivary glands (Hoffmann, 1938: 947), which are lacking in D. areolata (Pruvot-Fol, 1952: 414). We sectioned the whole anterior gut, so that even very small, sessile salivary glands would have been seen. The numerous subepithelial glands of the muscular oesophagus (0) were noted in the sections. As Bergh's figures of D. areolata (1880: PI. 11, Figs. 3-11) are not available, we expected from his text (1896: 457) to find small, dark yellow salivary glands at the cardia. From our dissection of Dendrodoris atropos we supposed the big, flat dorsal gland (ze) in this region to be the blood gland. However, its structure agrees with that of the honeycomb glands in the wall of the oesophagus of D. atropos (Fig. 19, ue), hence it is a secretory, not a lymphatic, gland, and its secretion is discharged by a duct. The sphincter (Fig. 18, iz) of the cardia and the stomach (s) of Doriopsilla areolata are like those in Dendrodoris atropos. As in Eliot's material (1906b: 148), the typical white net on the notum of D. areolata is not preserved or not developed in the present 1962] Marcus & Marcus: Opisthobranchs 475 specimen. The number of rhinophorial perfoliations is a little smaller than the originally indicated 25. Nevertheless, we think that our determination is reliable. The number of branchiae is known to vary from three (Eliot, 1906b: 148) and four (Pruvot-Fol, 1953: 91-92) to six (Pruvot-Fol, 1952: 412). Nobre (1938-40: 47) considers Doriopsilla paulinoi Oliveira, 1895, as a separate species, by reason of its very high tubercles. Eliot's material from the Cape Verde Islands has tubercles of usual height and seems to belong to areolata. Family PHYLLlDIIDAE Phyllidiopsis (Phyllidiopsis) papilligera Bergh, 1890 Figures 20-24 Reference.-Bergh. 1890: 176-178, PI. 2, Figs. 7-14. Material.-l. Ridge 5 mi. SE of Lameshur Bay, St. John, Virgin Islands; 60 ft., found under ledge after rotenone; John Randall and Tony Chess col.; 5 February 1960, one specimen: UMML 30. 2697. -2. Chaplin Station 505; South shore, Little Bahama Bank, Grand Bahama Island; 1 July 1959, one specimen: UMML 30. 2698. Further distribution.-Gulf of Mexico, 101 fms., 25°33'N, 84°21'W, about 400 km W of Cape Sable, Florida. Description.-Body flat, stiff, with numerous spicules, which project on the sides of the slug from the Bahama Bank (Fig. 22). This animal is 13.5 mm long, 6 mm broad. The slug from St. John (Fig. 20) is 30 mm long, 18 mm broad, and 7 mm high. Its rhinophores are completely withdrawn, their black clubs with about 20 leaves, not all complete. The tentacles (Fig. 21, k) are two round flaps, with broad bases, united for a short way in front of the mouth (rna), and furrowed on the outer side. The foot of the larger animal is 21 mm long and 7 mm broad, that of the smaller one 12 mm long, and too much folded for measuring the breadth. The anterior border of the foot (io) is notched; on either side lie about 100 branchial leaflets (zi). These are black in the smaller specimen, white in the larger. In the latter the genital papilla ( vo) projects in the anterior sixth of the right series of gills. The ground color of both animals is white, and both have black circles on the back. Three large ones on either side and an unpaired median circle in front occur in both slugs; smaller, irregularly scattered black areae are more numerous in the larger specimen (Fig. 20). 476 Bulletin of Marine Science of the Gulf and Caribbean [12(3)

(J-.:

21 :n 24 FIGURES 20-24. Phyllidiopsis papilligera Bergh. 20, specimen from St. John; 21, ventral view of anterior end of same; 22, specimen from Bahamas, drawn to same scale: 23, anterior part of alimentary tract, dorsal view; 24, ventral view of same. 1962] Marcus & Marcus: Opisthobranchs 477 The black blotches of the notal margin show through on the ventral side. The large black circles and many of the smaller ones bear warts or papillae with light tips. Possibly these now white prominences were yellow in life, as they are denser than the epidermis between them. The warts on the large blotches are beset with several smaller ones or have irregular outlines due to the union of small warts. There are also entirely white warts and others with only small black spots between the black areae. Along the middle of the notum the warts form a confluent ridge. The rhinophore sheaths open on light warts (x), and the longitudinal anal slit (ar) on a white wart with two black spots. Some of the papillae are of equal breadth along their entire length, others are broader at the base; flask-shaped and claviform papillae as in Bergh's specimen were not seen. The peritoneum is pigmented. The oral pore (rna) leads into a broad muscular cavity or buccal vestibule (j), whose walls contain glands, but the organ is not wrapped in clusters of oral glands. The posterior oral gland or ptyaline gland (g) opens into the inner part of the sacculiform oral tube (oc). The fundus of the gland is directed forwards and ends with a narrow curved caecum. Bergh (1890: 177) took this blind, duct-like inner end for the discharging duct of the ptyaline gland and thought that it opens immediately below the mouth, and Pruvot-Fol (1957: 116) was bewildered by Bergh's drawing (PI. 2, Fig. 13) and text. The long pharynx (u) which follows the broad oral tube is cylindrical. From the hind end of the oral tube it courses forwards to the level of the fundus of the oral vestibule, and then curves backwards. In this curve lies the nerv,e-ring (n). Distant from the latter the buccal ganglia (cc) are located at the end of the pharynx, which is separated from the following wider oesophagus by a constriction. The small salivary glands which Bergh figured immediately behind the buccal ganglia were not seen. The oesophagus (0) courses backwards with a narrow loop held in place by a muscle (z). The reproductive organs were not dissected, in order to leave the notum intact. Discussion.-The Phyllidiidae are the longest known of all nudibranchs (Bergh, 1876b: 378) and were figured as early as 1735. Systematically, however, they are not well known .even today, because color and sculpture, both vague qualities in preserved slugs, are the 478 Bulletin of Marine Science of the Gulf and Caribbean [12(3) principal systematic criteria in these animals without radula and with rather uniform gills and spiculation. The most important references for the Phyllidiidae are: Bergh (1876a; 1889; 1892: 1123 ff.), Eliot (1903a), and Pruvot-Fol (1956-1957). To our recent note on the genera (Marcus, 1960a; 912-13), we add that Ceratophyllidia Eliot ( 1903b: 250), with stalked processes of the notum, spherical or ovoid in shape, may b.e maintained as a subgenus of Phyllidiopsis (Eliot, 1906a: 674), and not be considered as a mere synonym of it (Bergh, 1905: 180, note). The warts of the present species are distinctly smaller than those in Ceratophyllidia africana Eliot, 1903, and C. grisea Eliot, 1910, so that it is better allocated to Phyllidiopsis (Phyllidiopsis ). In Phyllidiopsis Bergh, 1876, the anterior part of the oral tube, the muscular buccal vestibule, is not surrounded by the large glandular mass present in the other genera of the family. The tentacles are broadly attached. This is the only character recognizable without dissection, but it is not reliable. In the single specimen of Ph. papilligera Bergh (1890: 176) "no vestiges of tentacles were seen." The longitudinal muscles of Bergh's slug were evidently very much contracted, as is revealed by his measurements of the foot, 7.5 mm long and 6 mm broad. Therefore, we suppose that the tentacles were completely withdrawn under the anterior border of the foot. Coalesced tentacles hiding the mouth occur in Ph. berghi Vayssiere (1902: PI. 9, Fig. 11, v); the author described them in his diagnosis of the genus. Pruvot-Fol (1954a: 329) said "sans palpes," but the circular fold around the mouth, which she mentioned, are the palps. In addition to these two species from the Atlantic Ocean, eight others have been described, including two of Ceratophyllidia Eliot (1903b: 250; 1910b: 436). With the exception of Phyllidiopsis gemmata Pruvot-Fol (1957: 121), whose locality is not indicated, they are all from the Indo-West-Pacific Ocean. Phyllidiopsis carinata Eliot (1910 b: 435), from the Amirante Isles, is extremely similar to papilligera, but the "difference of habitat makes it improbable that the two animals are specifically the same," and "it must be confessed that if they had been found together, the discrepancies could be explained away" (ibid.; 436). In fact the bright white borders of the black areae constitute the only perceptible difference. But neither were the tentacles described nor was the oral tube dissected, so that the generic position of carinata cannot be defined. Very probably Pruvot- 1962] Marcus & Marcus: Opisthobranchs 479 Fol (1956: 63) is right to transfer this species to Phyllidia, as a synonym of Ph. ocellata Cuvier, 1804. Suborder EOLIDACEA Tribe CLEIOPROCTA Family FACELINIDAE Phidiana lynceus Bergh, 1867 References.-Bergh, 1867: 104-116; 1874: 615-618; Engel, 1925: 56, 61 fI. Synonym.-Ph. Selencae Bergh, 1879a: 560-563; Marcus, 1955: 178-181 (as selenkai); 1957b: 467 ff. (selenkai). Material.-SJHK 59-6. E. shore of Greater Lameshur Bay, St. John, Virgin Islands; littoral and sublittoral rock area; Hermann Kumpf, Gilbert L. Voss, and C. Adams col.; 22 January 1959, one specimen: UMML 30. 2725. Further distribution.-St. Thomas, Virgin Islands; Guadeloupe; Bra- zil: Bahia; Cabo Frio (22°57'S, 42° I'W); Rio de Janeiro; Angra dos Reis (22°58'S, 44°19'W); common on the coast of S. Paulo from Ubatuba (23°27'S, 45°6'W) to Cananeia (2503'S, 4r50'W). Description.-The preserved animal is 7 mm long, 4 mm broad, and 4 mm high. The anterior end of the foot is dilated into a semicircular disk. The tail is very short, hardly projecting behind the last cerata. Each of the lateral fields that bears cerata is slightly broader than the middle area without cerata. The groups of cerata are indistinct, and their delimitation is somewhat arbitrary. On the right side 36 cerata form about eight rows dorsal to the genital opening; they belong to the anterior liver. The two following groups on the right side are a middle one of 28 cerata in about six rows, and a hindmost of 12 cerata in five rows; these are, in Odhner's terminology (1939: 50), the anterior and posterior right-hand group of the left liver. The anus lies between these groups on the boundary between the third and the last fourth of the body-length. On the left side the liver has 22 anterior cerata. The posterior area comprises 33 cerata of which 19 anterior and 14 posterior ones may be distinguished. The pericardium lies in the middle of the body; the neurilemma of the central nervous system is not pigmented. The border of the masticatory process bears 24 denticles. The radula consists of 16 teeth of which the two hindmost are quite new and pale. The median cusp has four to six small denticles on each side, whose direction may be rather 480 Bulletin of Marine Science of the Gulf and Caribbean [12(3) parallel or more transversal to that of the cusp. On either side of the latter the cutting edge bears four to six strong, sharp points. The penial stylet is blackish brown, in the present specimen broken at the tip, but evidently not different from that of selenkai. Discussion.-The specimen from S1. John, separated from the original locality by the 3.3 km wide Pillsbury Sound (Kumpf and Randall 1961: 544), confirms Engel's (1925: 57) and our supposition (Mar- cus, 1955: 181) that lynceus and selenkai are one and the same species. Neither the characters of Engel's key (1925: 71) nor ours (1957b: 472) are disjunctive. The disciform dilatation of the anterior end of the sale, still considered as a peculiarity of lynceus (Engel, 1925: 61, 63), occurs also in our material of selenkai. The position of the anus is the same in both. Only the distinction of four right groups of cerata in lynceus brings about a fictitious dissimilarity. By different contraction of the tail, the anus lay 2 mm from the posterior end in a specimen of lynceus 12 mm long, and 7 mm in one 15 mm long (Engel, 1925: 30). Bergh (1879a: 563) said that the shape of the penial stylet of selenkai is quite different from that of lynceus, but did not describe nor figure this difference (Engel, 1925: 67). The number of denticles on the masticatory border and the pigment of the neurilemma are evidenced as variable characters by the present speCImen. Family AEOLlDIIDAE Spurilla neapolitana (Delle Chiaje, 1823) Material.-Ocean side, Key Largo, Monroe County, Florida; J. Vallee col.; 10 April 1961, one specimen: UMML 30. 2726. Further distribution.-Mediterranean Sea; Atlantic coast of France and Morocco; Canary and Cape Verde Islands; Sargasso Sea; Virginia Key, Florida (Marcus, 1960b: 187); Texas (Marcus, 1959b: 258); Brazil, southward to Sao Paulo. Subclass PROSOBRANCHIA Order MESOGASTROPODA Family LAMELLARIIDAE Subfamily Lamellariinae Lamellaria leucosphaera Schw,engel, 1942 Figures 25-28 References.-Schwengel, 1942: 62-64, PI. 3, Fig. 8; Perry and Schwengel, 1955: 126, Figs. 327a, b. 1962] Marcus & Marcus: Opisthobranchs 481 Material.--SJHK 59-6. E. shore of Greater Lameshur Bay, St. John, Virgin Islands; littoral and sublittoral rock area; Hermann Kumpf, Gilbert L. Voss, and C. Adams col.; 22 January 1959, one female. UMML 30. 2727. Further distribution.-Pine Island Sound, off Red Fish Pass, Captiva Island, Florida, 1.5-2 fms. Remarks.-The species is well characterized by the shape of the shell, which was compared with that of Marsenina globosa Perry, 1939 (Perry and Schwengel, 1955: Fig. 169). The spire of leucosphaera is, as mentioned by Schwengel (1942: 63), more produced. The shell of the present animal is 9 mm long, 6.5 mm broad, and 4.5 mm high. The dark digestive gland is also in our specimen visible through

Sl"tl-1'Y\.o I I '----l 25

27 FIGURES 25-28. Lamellaria leucosphaera Schwengel. 25, shell; 26, three rhachidian teeth; 27, cusp of rhachidian tooth; 28, lateral tooth. 482 Bulletin of Marine Science of the Gulf and Caribbean [12(3) mantle and shell, due to the absence of pigment in the epithelium lining the pallial cavity. Description of radula.-The radula contains about 58 rows. The rhachidian tooth has almost equal legs; its cusp points to the left or to the middle, exceptionally even to the right. It has four to six denticles on each side, those on the left a little larger. The lateral tooth has five to six strong denticles on the upper, and 10-13 finer ones on the lower cutting edge. Discussion.-Warmke and Abbott (1961: 89) record L. rangi (Bergh, 1853) from the Gulf of Mexico and Puerto Rico and give a descri ption and photograph of its shell (pI. 17, B). Bergh (1853: 94) indicated that a Marsenia (now Lamellaria) from 51. Thomas, Virgin Islands, had been mentioned and drawn by Rang as "Sigaret" and copied two figures of Rang (1853: PI. 5, Fig. 7). Bergh gave the name rangii to this material. Later on (1886: 165) Bergh united Rang's "Sigaret" with Lamellaria perspicua (Linne, 1753). He did the same with two species which he had related to rangii in 1853. Nevertheless, Bergh continued to use the name rangii (1886: 170) for Rang's material from 5t. Thomas without description. Hence Lamellaria rangii (Bergh, 1853) needs reexamination of Rang's material from St. Thomas.

ZOOGEOGRAPHIC REMARKS The new species, Hexabranchus morsomus, the first Atlantic repre- sentative of an Indo- West-Pacific genus, must be left aside in the zoogeographic analysis of the present collection. The largest group, 35.7 per cent, is formed by autochthonous West Indian species. The next, 21.4 per cent, is made up of species whose range extends from the West Indies, or even from South Carolina, to southern middle Brazil. This group would certainly be more numerous were not the depths in which the present and the Brazilian material were gathered somewhat different. The UMML-collection does not come as exclusively from the tidal zone as our slugs from Brazil. Three groups, each with 14.3 per cent, are composed of (1) transatlantic species; (2) species distributed in warm waters of the Atlantic and the Indo- West-Pacific Ocean, and (3) species from Middle Japan and the West Indies. Memhers of the last group may also occur on the coast of southern California or the adjacent warm water region, because their range seems to be due to the ancient Pacific-Caribhean connection. 1962] Marcus & Marcus: Opisthobranchs 483 It is true that this connection has been interrupted since the Middle Miocene, so that one would expect related, not identical, species. Of the species considered her,e, 57 per cent are stenothermal inhabi·· tants of warm water, 43 per cent are more eurythermal and live in tropical as well as warm temperate regions. Like our first collection from the Miami area (Marcus, 1960b), which did not contain any Dorididae at all, the present one is poor in doridids. It comprises only two incomplete, hence unidentifiable, specimens from St. John, Virgin Islands, one of which could not even be defined as belonging to the Cryptobranchiata. The opisthobranch fauna of the coast of Texas is very little known. It may, however, be mentioned that only one species of the present collection, Spurilla neapolitana, widely distributed in warm and warm temperate Atlantic seas, is also represented in the material that Joel W. Hedgpeth gathered, chiefly at Port Aransas (Marcus, 1959b).

LITERATURE CITED ABBOTT, R. TUCKER 1949. A new Florida species of the tectibranch genus Pleurobranchus. Nautilus, 62 (3): 73-78.

ALLAN, JOYCE 1950. Australian shells. Melbourne, Georgian House, xix + 470 pp., 44 pIs.

BABA, KIKUTARO 1938. Opisthobranchia of Kii, Middle Japan. J. Dep. Agric. Kyushu Univ., 6 (1): 1-19. 1949. Opisthobranchia of Sagami Bay. Tokyo, Iwanami Shoten, 194 + 7 pp., 50 pIs. 1959. The genus Pe/a/ijera and a new species, P. ramosa, from Japan. PubI. Seto mar. bioI. Lab., 7 (3): 337-338.

BERGH, RUDOLPH 1853. Bidrag til en monografi af marseniaderne. Dansk Vidensk. Selsk. Skr., (5)3: 1-119. 1867. Phidiana lyncells og Ismailia mons/rosa. Vidensk. MeddeI. Dansk naturhist. Foren., 1866 (7-9) :97-131. (Not seen.) 1872. Malacologische Untersuchungen, Heft 4. Elysiadae. In: Semper, C. Reisen im Archipel der Philippinen. Wissenschaftliche Resultate, 2 Theil, 1: 175-203. 1874. Beitrage zur Kenntniss der Aeolidiaden, 1. Verh. zool-bot. Ges. Wien, 23: 596-628. 1876a. Neue Beitrage zur Kenntniss der PhylIidiaden. Verh. zooL-bot. Ges. Wien, 25: 659-674. 1876b. Malacologische Untersuchungen, Heft 10. In: Semper, C. Reisen im Archip~1 der Philippinen. Wissenschaftliche Resultate, 2 Theil, 2: 377-427. 484 BulleTin of Marine Scienceof the Gulf and Caribbean [12(3) 1879a. Beitrage zur Kenntniss der Aeolidiaden, VI. Verh. zool. bot. Ges. Wien, 28: 553-584. 1879b. Die Doriopsen des atlantischen Meeres. Jahrb. malak. Ges., 6: 42-65. 1880. Die Doriopsen des Mittelmeers. Jahrb. malak. Ges., 7: 297-328. (Not seen.) 1886- Malacologische Untersuchungen, Heft 4, Suppl. 3-4. Die Marseniaden. 1887. In: Semper, C. Reisen im Archipel der Philippinen. Wissenschaftliche Resultate, 2 Theil, 4: 131-225; 227-285. 1889. Malacologische Untersuchungen, Heft 16 (2. Halb). Nudibranchien vom Meere der Insel Mauritius. In: Semper, C. Reisen im Archipel der Philippinen. Wissenschaftliche Resultate, Their 2: 815-872. 1890. Report on the nudibranchs. Reports on the results of dredging ... in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879- 80), by the U. S. Coast Survey steamer "Blake." Bull. Mus. compo Zool. Harv., 19(3) :155-181. 1892. Malacologische Untersuchungen, Heft 18. System der Nudibranchia- ten Gasteropoden. In: Semper, C. Reisen im Archipel der Philippinen, Wissenschaftliche Resultate, Theil 2: 995-1165. 1896. Uber die Gattung DoriopsilJa. Zool. Jb. Syst., 9 (3): 454-458. 1897. Malacologische Untersuchungen, Heft 5, 4 (1, 1-2). Die Pleurobran- ~hiden. In: Semper, C. Reisen im Archipel der Philippinen. Wissen- schaftliche Resultate, 7: 1-115. 1898. Malacologische Untersuchungen, Heft 5, 4 (1, 3). Die Pleurobran- chiden. In: Semper, C. Reisen im Archipel der Philippinen. Wissen- schaftliche Resulta te, 7: 117-158. 1900. Ergebnisse einer Reise nach dem Pacific ... Zool. Jb. Syst., 13: 207-246. 1902. Malacologische Untersuchungen, 4. Abt., 4 Abschn. Ascoglossa, Aplysiidae. In: Semper, C. Reisen im Archipel der Philippinen. Wiss- enschaftliche Resultate, 7: 313-382. 1905. Die Opisthobranchiata der Siboga Expedition. Siboga Exped., 50: 1-248. 1907. The Opisthobranchiata of South Africa. Trans. S. Afr. phil. Soc., 17(1): 1-144.

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EALES, NELLIE B. 1938. A systematic and anatomical account of the Opisthobranchia. Sci. Rep. Murray Exped., 5(4): 77-122. 1944. Aplysiids from the Indian Ocean, with a review of the family Aply- siidae. Proc. malac. Soc. Land., 26 (1): 1-22. 1952. On Barnardaclesia cirrhifera (Q. & G.) Ibid., 29 (2-3): 71-79. 1960a. Revision of the world species of Aplysia. Bull. Brit. Mus. (Nat. Rist.), 5 (10): 267-404. 1960b. Petalifera habei, a new species from Japan. Proc. malac. Soc. Lond., 34 (1 and 2): 12-18 and 112.

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