JANUARY 29, 1981 THE NAUTILUS ISSN 0(i2«-13.ll Vol. 95 No. 1 A quarterly devoted to malacology and the interests of conchologists Founded 1889 bv Henry A. PilsbiT- Cict of.-ieminal recep- tacle; eg, esophageal gland; espc, ejnthelial lining of spermatophore chamber; hg, hypiihranchial gland; il, in- ner lamina; inho, inhalant siphon and ocelli; j, jaw; Isg, left salivary gland; mes, mid-esophagus; od, odo7i- tophore; ol, outer lamina; os, osphradium; ospc, opening to spermatophore chamber; pes, posterior esophagus; pp, pallial papilkw; ppo, proxim/il pallial oviduft; r, radula; rex, ridge forming exhalant siphon; rpg, right pletiral ganglion; rs, radula sar; rsg, right salivary gland; rt, radular tensor muscle; sec, supraesophageal connective; seg, supraesophageal ganglion; sn, snout; sp, spennatophore; spc, spermatophore chamber; sr, sem.inal receptacle; t, tentacle; wbc, wall of buccal cavity. Vol. 95(1) January 29, 1981 THE NAUTILUS If : ^•^Xiu:* VC i*" rd B • •.'• . FIG. 4. Longitudinal section through the uihahmt siphon showing a pallial eye (Length of eye: 0.1 mm). A, Pallial eye in relation to mantle edge; B, Detail of pallial eye showing internal structure: bp, pigmented cells surrounding "cornea": ce, elongate epithelial cells comprising "cornea": rd, area interpreted as rods of retinal cells; rt, retinal cells: VC, vacuolated cells. staining cell walls and large nuclei filled with dark staining granules (Fig. 4, rt). These appear to be pigmented photoreceptor cells of the reti- na. A thick mass of large vacuolated cells with small nuclei and weakly defined cell boundaries surrounds the receptor cells. This last cell layer comprises most of the ocellus and is embedded in the muscular tissue of the mantle edge (Fig. 4, vc). When the mantle cavity is opened by a dorsal longitudinal cut, the layout of the mantle organs is typically cerithioid. The hypobranchial gland (Fig. 3A, hg) is a wide, thick structure extending back about one third the length of the mantle cavity. The rec- tum is a thick tube filled with several transverse layers of fine tubular fecal pellets that consist of fine carbonate sediment, green algal particles and detritus, and strands of filamentous green algae. It is detached from the mantle wall at its distal end where it becomes a free tube that opens about 3-4 mm behind the distal part of the pallial gonoduct. A deep fold in the mantle roof lies in apposition to the anus and corresponds to the exhalant siphonal ridge seen on the external mantle roof. The osphradium (Fig. 3A, os) is tan, thin and bipectinate, lies close to the ctenidium, and ex- tends most of the mantle cavity length. At its distal end it becomes a fine worm-like ridge which ends near the edge of the exhalant siphon. The ctenidium (Fig. 3A, ct) is monopectinate and comprised of numerous long triangular fila- ments. The pallial gonoducts are open in both sexes and males are aphallic. This arrangement is typically cerithioid and may be compared with what has been described for other cerithids (Houbrick, 1971, 1976, 1978). In females, the thick glandular pallial oviduct is basically a slit tube comprising outer and in- ner laminae (Fig. 3B, ol, il). There are no sperm collecting gutters or ducts in the wall of the outer lamina (Fig. 3B, ol) for most of its length, but the proximal end bears a large kidney- shaped spermatophore chamber (Fig. 3B, spc) in its wall. This lies close to the free edge of the outer lamina and appears as a large, light yellow structure with a finely wrinkled surface. When closely observed, the proximal part of the outer lamina is seen to be a complex structure that in- cludes a seminal receptacle (Fig. 3B, C, D, sr) and internal duct as well as the spermatophore chamber (Fig. 3D, spc). The spermatophore chamber opens to the lumen of the pallial ovi- duct by a latitudinal slit on the free edge of the outer lamina (Fig. 3C, D, ospc) and may contain as many as two spermatophores. Spermato- phores (Fig. 3D, sp) are pale yellow, tear shaped, and are roughly the size of the sper- matophore chamber. They are placed with their rounded ends lodged in the proximal part of the chamber, and when present, cause the chamber to bulge. The interior of the spermatophore chamber is lined with columellar epithelial cells (Fig. 3D, espc). Another thin latitudinal slit lies 8 THE NAUTILUS January 29, 1981 Vol. 95(1) along the edge of the spermatophore chamber (Fig. 3n. spc) and within the free wall formed by this slit is found the seminal receptacle (Fig. 3C, D, sr). The seminal receptacle appears to have a small duct (Fig. 3C, D, (isr) leading from it to the underside of the free wall. This opening is sur- rounded by fingerlike wrinkles and is easily seen. By means of this duct, sperm exit from the seminal receptacle into the slit and thence into the lumen of the pallial oviduct to fertilize ova as they move down the oviducal groove of the ovi- duct. There is no apparent connection between the spermatophore chamber and the seminal re- ceptacle and its duct, but sperm are free to move from one slit to the other. The exact mechanism of sperm transfer is unknown. Tiny pink ova were seen in the oviducal groove and develop- ment is presumably indirect. The alimentary system (Fig. 3E, F) of Gour- mya gourmyi is that of a typical herbivorous cerithiid. The mouth lies at the top of a bilobed snout, recessed between the lobes. A pair of smooth ovate chitinous jaws (Fig. 3E, j) with smooth cutting edges, each about 1 mm long and 0.73 mm wide, lie at the anterior end of the buc- cal cavity. The buccal mass is large and the long radular ribbon (Fig. 3E, r) ends in a thickened radula sac that curls upwards (Fig. 3E, rs). Two thick radular tensor muscles (Fig. 3E, rt) extend from the walls of the head and insert laterally on the posterior buccal mass. The paired salivary glands are loose string-like lobes and lie dorsally on the dorsal buccal mass and anterior esopha- gus, in front of the nerve ring (Fig. 3E). A por- tion of the left salivary gland (Fig. 3E, Isg) passes through the nerve ring. No salivary ducts were found. Immediately behind the nerve ring the esophagus narrows and makes a sharp turn upwards, expanding slightly. The mid-esopha- gus (Fig. 3E, mes) has a deep ventral food groove and a broad, flat dorsal food channel (Fig. 3F). A large paired esophageal gland, (Fig. 3E, eg) comprising two longitudinal strips, lies along the mid-esophagus. (Fig. 3F). Sections of this gland show that it has many fine deep folds and diverticula which may be seen through its thin dorsal wall. The posterior esophagus (Fig. 3e, pes) has numerous longitudinal folds but is otherwise simple in structure. The stomach is basically the same as in other cerithiids. It is unusual in having a very large chitinous gastric shield with an extensive base and a main sorting area with numerous serially arranged leaflets. The cerebral ganglia (Fig. 3E, eg) are about 2.1 mm long and are nearly fused, while the pleural ganglia lie below, close to the cerebrals. The supraesophageal connective (Fig. 3E, sec) is thick and the supraesophageal ganglion (Fig. 3E, seg) is moderately large. The RPG ratio (length of the pleuroesophageal connective di- vided by the sum of the length of the right pleural ganglion, the supraesophageal connec- tive, and the supraesophageal ganglion) was 0.62, indicating a moderately concentrated nerve ring. Records -LOYALTY ISLANDS: Mare Id (AMS C3714); NEW CALEDONIA: Noumea (NMV); Bambui, He des Pins (AMNH 186748); 30 meters, reef near Dumbea, (USNM 795115); 29 meters, outer slope St. Vincent Reef, off Baie de Vincent (USNM 795116); CHESTERFIELD ISLANDS: 7 meters, NE end, Anchorage Id (AMS C. 86642); Bampton Reefs (AMS C 108914; C 108913); Seaward face of He Longue (USNM 795122); 9 meters Bellona Reef (White- head, 1977:3); AUSTRALIA: 5-25 meters top of coral bommies, Brodie Cay, Marion Reef, 19°10'S, 152°17'E (AMS C 108915). DISCUSSION Synonymic Remarks -Crosse (1861:173) nam- ed this species after Mr. Gourmy, from whose collection the first specimens were described. Several authors (Sowerby, 1865; Tryon, 1887) have mistakenly referred this species to the potamidid genera Pyrazns Montfort, 1810 and Potamides Brongniart, 1810, but the similarities in shell morphology are convergent. Members of the Potamididae are estuarine snails and differ considerably from marine cerithiids. Crosse (1861:173) compared Gourmya gourmyi with Terebralia species (potamidids) but noted that the latter were ecologically very different from the marine dwelling Gourmya species. He also compared Gourmya with Cerithium adv^tum Kiener, 1841. The latter species only resembles Gourmya superficially and never has the aper- Vol. 95(1) January 29, 1981 THE NAUTILUS tural features that distinguish Gourmya. Ceri- thium adustum lacks the siphonal eyes, has a different radula and belong to the TheHcium lineage. Kobelt (1888:8) was unsure of the pro- per allocation of Gownnya gounnyi and assign- ed it, with some doubt, near a group of species that he placed in the genus Vertagiis Schu- macher, 1817 i = Rhinodavis Swainson, 1840) but which are now regarded as members of the genus Pseudovertagtis Vignal, 1904 (Houbrick, 1978). He noted that the base of the outer lip of Gourmya was similar to that seen in Pseudo- vergagtLS aluco (Linnaeus, 1758). This similarity is superficial because the animals are quite dif- ferent. Cossmann (1906) repeatedly spells Gour- mya incorrectly as Gourmyia. The pallial ocelli of Gourmya are unlike the well defined eyes found on its cephalic tentacles and on most mesogastropods. They appear to be more like the pit-shaped eyes of Haiiotis as depicted by Welsch and Storch (1973:176-177) but differ from Haiiotis by having a bundle of rod-shaped epithelial cells and a ring of dark pig- ment on the surface which I interpret as a lens. The ocelli somewhat resemble the eye of Tri- chotropis as shown by Fretter and Graham (1962:316). I have observed siphonal ocelli in one other cerithid, Rhinoclavis (Proclava) kochii (Philippi, 1848). Rhinoclavis species and some Cerithium species have large siphonal ganglia and elaborately pigmented inhalant siphons that seem to serve some sensory function. These have not been histologically investigated but probably bear some sensory structures. Johans- son (1956) described a very similar eye in the potamidid Tympanotomis. Thus, the presence of siphonal ocelli in Gourmya, although unusual, is not unprecedented among the Cerithiinae. The serially arranged leaflets in the sorting area of the stomach of Gourmya are similar to those I have seen in the stomach of Campanile symbolicum Iredale, 1917, family Campanilidae Douville, 1904 (Houbrick, 1980, in press). Cam- panile is another Tethyan relict and the last of a long lineage of a large family of Tertiary snails. This structure is not present in other anatomi- cally known species of Cerithiidae and Potami- didae. Ecology - Gourmya gourmyi, although uncom- mon in museum collections, is probably not a rare gastropod in its restricted range and habitat. Cernohorsky (1978:53) stated that it lives in the intertidal zone but this is erroneous. All museum specimens have been collected at depths ranging from 5-30 meters and at an average depth of 17.5 meters on rocky substrata associated with coral reef slopes. According to Australian collectors, specimens are usually found on algal covered rocky surfaces on fore reef drop-offs. As divers using SCUBA investi- gate that zone in this part of the Pacific, more specimens will undoubtedly be found. The most striking feature of the shell of this species is the unusual, centrally placed siphonal canal over which extends the base of the outer lip. These peculiarities of the aperture and siphon create a flattened circular apertural plane that allows the snail to withdraw its head and foot and clamp down on the hard substra- tum for protection. Communication with the ex- ternal environment is maintained through the siphonal canal by means of the ocelli and sen- sory receptors on the siphonal mantle edge. Another deterrent to predation is the thickened varix on the edge of the outer lip. No observa- tions have been made on living animals and their associations but most live-taken specimens have Capulus danieli (Crosse) attached near the shell apex. Stomach contents, fecal pellet analysis and the anatomy of the alimentary system in- dicate that Gourmya is a herbivorous grazer. The relatively long radular ribbon suggests a grazing habit on coarse surfaces. Fossil Record -Gourmya romeo (Bayan, 1870), a Tethyan Eocene species, is unequiv- ocally a Gourmya species and is well illustrated by Bayan (1870: pi. 9, fig. 5) and Cossman (1906: pi. 1, figs. 8-9). Its shell shape is very close to the living species, Gourmya gourmyi. Cossmann (1906:68) stated that Bayle, whose manuscripts were used by Fischer (1884) in proposing Gour- mya, designated Cerithium romeo Bayan as the "genoplesiotype" of Gourmya. Both Bayan (1870:37) and Cossmann (1906:68) noted its resemblance to the living species described by Crosse (1861:171-173) as Cerithium gourmyi, but it is unlikely that the two are conspecific. An Oligocene species, Cerithium ocirrohoe Or- 10 THE NAUTILUS January 29, 1981 Vol. 95(1) bigny, 1850, has also been referred to Gourmya by Vignal (1897:69-70) and Cossmann (1906:69). I have not examined specimens of this species, but illustrations of it in the literature support its allocation to Gourmya. Cossmann (1906:69) fur- ther cited the Miocene species Ceritkium kiips- teini Michelotti, 1847 and Cerithium geminatum Grateloupe, 1832 (non Sowerby, 1816) as rep- resentatives of Gourmya. I have not seen these species and cannot comment on their allocation to the genus. I have examined the holotype of Cerithium parungpo7denge7ise K. Martin, 1899 (RMGM St 10391), a Pliocene species from Java, which, as K. Martin (1899:204) and Cossmann (1906:69) remarked, appears to be closely re- lated to Gourmya gourrnyi. I believe that this fossil is either the direct ancestor of Gourmya gourmyi or conspecific with it and am inclined to accept the latter opinion. Many other living cerithids have records extending back as far as the Miocene. Geographic Range -(Fig. 5). The range of this species is restricted to the New Hebrides (Cer- nohorsky, 1978:53), New Caledonia, the Ches- terfield Islands and Marion Reef, in the Coral Sea. Conclusions -I regard Gourmya as a good genus because its lineage may clearly be traced in the fossil record to the Eocene. The living species' habitat in deeper waters of coral reefs FIG. 5. Geographic distribution 0/ Gourmya gourmyi. suggests that members of this genus exploited an adaptive zone different from those of most other cerithiid groups. The peculiar features of the shell, such as the shape of the aperture, outer lip and siphonal canal, further set this group apart from other cerithiids. The presence of siphonal ocelli, a highly developed esophageal gland, large gastric shield and the arrangment of the spermatophore chamber and seminal re- ceptacle at the proximal end in the outer lamina of the pallial oviduct are distinctive anatomical features that support the standing of Gourmya as a separate group. Open pallial gonoducts, aphallic males and the basic anatomy establish its inclusion in the Cerithiidae and suggest a close relationship with the genera Cerithium Bruguiere, Pseudovertagus Vignal, and Rhino- clavis Swainson. Members of the genus Gourmya were present in the Tethys Sea from the Eocene through the Miocene but became extinct after the Miocene and the closure of the Tethys. A fossil from Java confirms the presence of the genus in the Indo- Pacific during the Pliocene. The sole survivor of this lineage, Gourmya gourmyi, is today restricted to island groups in the Coral Sea around New Caledonia. ACKNOWLEDGMENTS I thank Dr. Philippe Bouchet, of the Paris Museum, and Dr. Winston Ponder of the Aus- tralian Museum, Sydney, for supplying me with preserved specimens and providing facilities for dissection. I also thank Dr. William K. Emerson, American Museum of Natural History, and Mr. Janssen of The Leiden Museum for the loan of specimens in their charge. The original draft of this paper was reviewed by Dr. Edward Petuch, University of Maryland, and Dr. Joseph Rose- water, Smithsonian Institution. Ms. Cathy Lamb kindly proofread the final manuscript and assisted with the preparation of material for SEM. Photography was done by Mr. Victor Krantz of the Smithsonian Photographic Serv- ices. Photomicrographs of the radula were sup- plied by the Smithsonian Scanning Electron Microscope Laboratory. Part of this research was supported by a Smithsonian Research Foundation Grant. Vol. 95 (1) January 29, 1981 THE NAUTILUS 11 LITERATURE CITED Bayan, F. 1870. Etudes faites dans la collection de I'Ecole lies Mines sur des fossiles nouivaiut ou mal coymits. Pre- mier Fascicule. Mollusques Tertiairies. Paris, 162 pp, 20 pis. Bruguiere, J. G. 1789. Encyclopedie Methodique, Histoire Naturelle des Vers. Paris, 1(1): 344 pp. Brongniart, A. 1810. Sur des terrains qui paroissent avoir ete sous I'eau douce. Annales museum d' Histoire Naturelle de Paris. 15(89-90):357-405, pis. 22-23. Cernohorsky, W. 0. 1978. Tropical Pacific Marine Shells. Sydney, 352 pp, 68 pis. Cossmann, M. 1906. Essaif de Paleoconchologie Comparee. vol. 7. Paris, 248 pp. Crosse, H. 1861. Description d'especies nouvelles. Journal de Conchyliologie 9:171-173, pi. 6, figs. 1-2. Dance, S. P. 1974. The Collector's Encyclopedia of Sliells. New York 288 pp, illustrated. Douville, H. 1904. Mollusques Fossiles, In: Morgan, J. De. Mission Scientifique en Perse. Vol. 3, Etudes Geologi- ques, part 4, Paleontologie: 191-380, pi. 25-50. Fischer, P. 1884 (1880-1887). Manuel de Conchyiiologie et de paleontologie conchyliologique. Paris, xxiv + 1396 pp, 23 pis. Fleming. J. 1828. Mollusks, Encyclopedia Britannica. sup- plement to editions 4-6, vol. 3, part 1. Edinburg. Fretter, V. and A. Graham. 1962. Britwh Prosobranch Mol- lusks. Ray Society, London. 755 pp, illustrated. Grateloupe, J. D. S. 1832. Tableau (suite du) des coquilles fossiles qu'on rencontre dans les terrans calcaires ter- tiaires (faluns) des environs de Dax, department des Landes; par M. Grateloup, membre honoraire. 5'" Article. Actes de la Societe Linneenne de Bordeaux. 5(29):263-282. Houbrick, R. S. 1971. Some aspects of the anatomy, repro- duction and early development of Cerithium nodulosum (Bruguiere) (Gastropoda, Prosobranchia). Pacific Science 24(4):560-565. 1974. The Genus Cerithium in the Western Atlantic. Johnsonia. 5(50):33-84, pis. 13-48. 1978. The family Cerithiidae in the Indo-Pacific, Part 1: The genera Rhinoclaris. Pseudovertagus and Clavocerithium. Monographs of Marine Moll usca. No. 1: 1-130, 98 pis. Houbrick, R. 1980. Anatomy, biology and systematies (jf Campanile symbolicum Iredale with reference to adaptive radiation of the Cerithiacea (Gastropoda: Prosobranchia). Malacologia, in press. Iredale, T. 1917. More molluscan name changes, generic and specific. Proceedings of the Malacological Society of Lon- don. 12(6):322-330. Johansson, J. 1956. On the anatomy of Tympanotonus fus- catus (L.), including a survey of the open pallial oviducts of The Cerithiacea. Atlantidae Report. No. 4:149-166, pi. 1. Kiener, L. C. 1841 (1841-1842). Species general et icono- graphie des coquilles vii'antes. Genre Cerite. Paris, vol. 5, 104 pp, 32 pis. Kobelt, W. 1888-1889. Die Gattung Cerithium. 297 pp, 47 pis. In Martini, F. H. W. and J. H. Chemnitz, Neues sys- tematisches Conchy lien-Cabinet, etc., 1(26). Nurenburg. Linnaeus, C. 1758. Systema naturae per regno tria naturae. Editio decima, reformata. Stockholm, vol. 1, Regnum animale, 824 pp (Jan. 1). Martin, K. 1899. Die Fossilien von Java. Sammlungen des Geologischen Reichs-Museums in Leiden. Neue Folge, 1(6-8):133-221, pis. 36-45. Michelotti, G. 1847. Descriptions des Fossiles des terrains Miocenes de I'ltalie Septentrionale. Hollandsche Maat- schappij der Wetenschappen, Haarlem. Natuurkundige Verhandeiingen 3(2): Monterosato, M. 1890. // naturalista SicUiano 9(7): 140- 151; 157-166. Montfort, D. de. 1810. Conchyiiologie systematique et class- ification methodique des coquilles. Paris, 2 vol., 676 pp. Nordsieck, F. 1968. Die europdischen Meeres-Gehdu.se- schnecken ( Prosobranchia) vom Eismeer bis Kapverden und Mittelmeer. Stuttgart, 273 pp, 31 pis. Orbigny, A. d'. 1850. Prodrome de Paleontologie Strati- graph ique universelle des Animauj: Mollusq^tes et Rayon- nesfaisant suite au cours Elementaire de Paleontologie et de Geologic Stratigraphiques. Paris, 1269 pp. Schumacher, C. E. 1817. Essai d'une nouveau septeme des habitations des vers testaces. Copenhagen, 287 pp, 22 pis. Sowerby, J. 1816. The Mineral Conchology of Great Britain. London, vol. 1. Sowerby, G. W. 1855. Thesaurus Conchiliorum. or mono- graphs of genera of shells. Vol. 2, Cerithium: 847-859, pis. 176-756. London. 1866. As above. Supplementanj. pi. 290. Ceri- thium. 1865. In Reeve, Conchologia Iconica: or illustra- tions of the shells of molluscous animals, vol. 15, Ceri- thium. 20 pis. -I- index. London. Swainson, W. 1840. A treatise on Malacology or the Natural History of Sliells and Shellfish. London, 419 pp. Thiele, J. 1931. Handbveh der Systematisches Weichtier- kunde. Jena, 2 vols. Tryon, G. W. 1887. Manual of Conchology: structural a7id >' Clam) (Miller and McClure, 1931) it has not been estabhshed whether these clams could survive long periods in environ- ments similar to those in ships of the period. Britton and Morton (1979) also attribute the im- portation of C. fluminea to the Chinese but place the introduction of the founding population sometime during the mid-1930's when many Chinese came to the United States and Canada to escape national and international conflicts in Asia. The present report places the arrival of C. Vol. 95(1) January 29, 1981 THE NAUTILUS 13 fluminea in North America during the early- to mi(i-1920's. The absence of other Canadian records of Cor- hicula fluminea raises questions about its biology and distribution. Sport fishermen have used C. fluminea as a bait for many years (Fox, 1969; Britton and Morton, 1979) and the spread of this species in the United States has been at- tributed to these sportsmen who throw unused clams into streams (Britton and Morton, 1979). Abbott (1975) noted tropical fish hobbyists may similarly be responsible for the spread of these clams. Since C. fluminea is a consecutive pro- tandrous hermaphrodite (Kraemer, 1978) very few clams are necessary to establish a popula- tion if environmental conditions are within ac- ceptable limits for survival. It may be that USNM 363020 were discarded, either as bait or as the remains of a meal, into waters whose physicochemical characteristics were unsuit- able. This speculation is not supported, how- ever, by climatic, geologic and phytogeogi'aphic data for British Columbia (Clarke, 1973) which demonstrate that the environment of the south- western portion of the province is like that of western Oregon and Washington and northern California where C. fluminea has thrived for over 30 years (Fox, 1969). The absence of C. fluminea in the Canadian Interior Basin (Clarke, 1973) and present-day British Columbia also supports the hypothesis recommended by Thompson and Sparks (1977) that C. fluminea is incapable of being carried to new localities in the gastrointestinal tract of migratory waterfowl. The specimens in USNM 363020 are signifi- cant as they are the only record of Corbicula fluminea in Canada and also the earliest docu- mented specimens of the species in North America. ACKNOWLEDGMENTS I wish to thank Arthur H. Clarke and Joseph Rosewater, United States National Museum of Natural History for making their facilities avail- able to me. I am also indebted to Muriel F. I. Smith, Museums of Natural Sciences, National Museums of Canada, Daniel Quayle, Pacific Biological Station and Russell Jensen, Delaware Museum of Natural History for their research of Corbicula records. I also wish to thank Diane M. Muni for her assistance in gathering distribution records and R. Tucker Abbott for his sugges- tions and review of the manuscript. LITERATURE CITED Abbott, R. T. 1975. Beware the Asiatic freshwater clam. Tropwal Fish Hobkjists 23:15. Britton, J. C. and B. Morton. 1979. Corhicula in North America: the evidence reviewed and evaluated. Proc. First Internat. Corbicula Symp. pp. 250-287. Burch, J. Q. 1944. Checklist of west American mollusks. Minutes Conchol. Club California 38:18. Clarke, A. H. 1973. The freshwater molluscs of the Canadian Interior Basin. Malarologia 13:1-509. Clench, W. J. 1970. Corhicula marulensis Philippi in lower Florida. The Nautilus 84:36. 1971. Corhicula manilensis (Philippi) in Okla- homa. The Nautilus 85:145. Crumb, S. E. 1977. Macrobenthos of the tidal Delaware River between Trenton and Burlington, New Jersey. Chesapeake Set. 18:253-265. Eckbald, J. W. 1975. The Asiatic clam, Corhicula. in the upper Mississippi River. Th£ NuMtilui; 89:4. Fox, R. 0. 1969. The Corhtcula story: a progress report. Western Soc. Malacol., 11 pp. 1970. The Corbicula story: chapter two. West- ern Soc. Malacol., 5 pp. Haas, F. 1954. Non-marine mollusks from the Pacific Slope of North America. The Nautilus 67:94-96. Kraemer, L. R. 1978. Corhicula fluminea (Bivalvia: Sphae- riacea): the functional morphology of its hermaphroditism. Bull. Amer. Malacolog. Union 1978:40-49. Mathiak, H. A. 1979. A River Survey of the Unionid Mussels of Wisconsin 1973-1977. Sand Shell Press (Horicon, Wis- consin). 75 pp. Miller, R. C. and F. A. McClure. 1931. The freshwater clam industry of the Pearl River. Lingnan Sci. Jour. 10: 307-322. Morris, J. S. and R. W. Taylor. 1978. A survey of the fresh- water mussels (Bivalvia: Unionidae) of the Kanawha River of West Virginia. The Nautilus 92:153-155. Sinclair, R. M. and B. G. Isom. 1963. Further Studies m the Introdwed Asiatif Clam (Corbicula) in Tennessee. Ten- nessee Stream Pollution Control Bd., Tennessee Dept. Publ. HIth., v-^79pp. Thompson, C. M. and R. E. Sparks. 1977. Improbability of dispersal of adult Asiatic clams, Corbicula manilensis, via the intestinal tract of migratory waterfowl. Amer. Midi. Nat. 98:219-223. 14 THE NAUTILUS January 29, 1981 Vol. 95(1) ANALYSIS OF SOME CHARACTERISTICS IN TWENTY FOUR POPULATIONS OF WESTERN U.S. PLEUROCERID SNAILS' Branley A. Branson and Daniel H. Barrett Department of Biological Sciences Eastern Kentucky University Richmond, Kentucky 40475 ABSTRACT Statistical analysis of the average obesity index and average apertural index in 2Jt populations of pleurocerid snails from the western United States indicates broad overlapping of those characteristics in Goniobasis plicifera and G. silicula and a clusteriyig ofG. orickensis, G. chacei, G. coquillensis, G. yreckaensis, G. hemphilli maupinensis, G. hemphilli dallesensis and G. plicifera bulimoides distinct from the G. plicifera-silicula complex. This cluster of species andlor races needs to be re-elevated in order to determine interrelationships. INTRODUCTION In its natural western U.S. range, the family Pleuroceridae was apparently rather wide- spread during Tertiary times (Henderson, 1935c), becoming progressively more segre- gated and depauperized in individual basins with the post-Pleistocene dessication of various drainages. At present, representatives of the family are distributed from British Columbia through western Washington and Oregon to northern California, but not extending south to San Francisco (Henderson, 1932). There are a few additional species in the western United States and Canada, such as the so-called Goniobasis columbiensis Whiteaves from the up- per Columbia River in eastern British Columbia, a species which is probably conspecific with G. livescens (Menke) of the Niagara River and many Great Lakes tributaries (Goodrich, 1937). Furthermore, there are a few highly depauper- ized pleurocerids isolated in some Great Basin springs in Washoe County, Nevada, Lassen County, California, and some Columbia River tributaries. However, Goodrich (1935, 1944) judged these species to be more closely related to eastern U.S. species than to those of the Pacific slope. It is the Pacific species which are very confus- ing. Henderson's (1935a, b) work on this group 'Supported by Sigma Xi-RESA ami P>asU'rn Keiitiici.. Cf-> COOCCCCCC : C = C — cv c 1-^ c c c='-- cc c c c D_r ai-" =C CO ci— s\r s'~r o^- qnC C(— . cf-. =^r C-= c_r ci3 c_= =-= cir. cccccocco If^ Crv CC\; =(— C .^ C -:r C T-", :t% cn-^ =_=■== ==; =C =Cv f-i C (> <- c I CCCf-'Crv.Cc^Cf^ C-:r E_=^ c-:r cm -- nC C vT 1-- -=: ~- -C r- Br^ ccc =f-\cf-' c,:rcc: cc cC co c'-- c- c*c cnC c>c CSC C'C CC-- cr- ' — ■ c _=■ = ~ c ■Lr\ c 1.-. 5^ 5^ S^ -b ' r- r^ sC r^ I— C I- c^^ O- O CnC sC >C ^C c ^- >- r- C occcccoco c^c-cc c>.c:cvc:p- csT cc c?- er'>=.-^ =:f— cf- cc *c cr^cr-cc cc; cc cc cc ccn 5. ccccccccc ^-^ ^« *^J w^ ^* *— b — s^-' li 1 CsC Of-' E-cc-'^clAco.i cc; cr>*. ICCCC\.CCMCC\:C^C-:rC_C^C1_'\ * I CCOCCCCCi I (T' C — = -r • C 'iT =-r5?^c *^»c t B \f\ C »-* 4 C O C .-' ccvjccjc'^c'^c-r VN *\j^»vC » Cv», «C =Cs»r-i»_3! Pv ^ C 18 THE NAUTILUS January 29, 1981 Vol. 95(1) O a. a ■^ o 5 g CQ (Or-' cpiCJ CO m r^ COCO ••CO \0 sO -3 £>■ CC CN mO 0)0 OjCm KCV) o)'^Rf*^ CO COCOCO COCO Z€ S8 cocc CO t:o CO ! S8 SS Sc O r-J * o c o i O * O CO I W Q in Q I C O C O 38 Se O I "^ ~ O « C # O * O .«^ SSSc I mcoir-icni-^inr-^ojcj I COCO COCO CO CO CO CO cc coco * o * o i c o c c : o c o c O : t o » O J o cocococococo«o*o*o t c o c o r- r-- (-1 3r-l tn Po r SSS) : o * o * o * I :o*0*0#o *o*oc( »S 3 0*0*1-'*. : o c o c o * o ^OJf^OsOt^f^CuPO V> SPE>£Q'i r-ncc o c o *0_OCOUO_Ot.O»C Ar-lfrr-" 1 n I tfjCtor-'woonwtnrjtnfnmr^mjm-gnv; I d I riococococccococococo sgss s« s«sssl»s,l»s VAOOsCOoTCr. n~i bcoco CO CO CO coco *0 CO CO CO CO co*o*r si sSssa; So S3 s< O \A nC t CO Os (-\ \/\ O O vO o )(\jiD'^n-3 -305-:? \r4 :ococo*o co*o * "S * 3S _T \A .-t Ca On I 0*0C0*0»0#' ;3 ^ Vol. 95 (1) January 29, 1981 THE NAUTILUS 19 plicifera bulimoides, G. coquilleTisis, and popula- tion 6 of G. yrekaensis obscura, and the third cluster for G. orickensis, G. draytoni and G. chacei. Goodrich (1942) listed G. plicifera bulimoides as a synonym of G. plicifera, and all of Hender- son's (1935a, b) other forms as species incerta, hinting that all of these were probably variants of either G. plicifera or G. siiicula, or both. However, in view of the results reported here, this view does not appear acceptable. Goodrich (1942) himself stated that, "until a system of nomenclature shall have been devised that can deal with peculiarities of groups, clusters, or col- onies, each by itself, it appears wasest to keep to the course followed in the treatment of the Pleu- roceridae east of the Rocky Mountains." In the eastern United States, nearly every river sys- tem has its own peculiar pleurocerid fauna, even though some of the systems lie in close prox- imity to one another. If we follow Goodrich's (1942) logic, extrapolating the condition of eastern streams to the West, then it should follow that western drainages may also have ex- perienced pleurocerid divergence so that differ- ing drainages would possess differing species complexes of this complicated molluscan family. Hence, it is concluded that Henderson's (1935a, b) species, possibly including G. plicifera buli- moides, actually form a closely related complex of species and/or races as distinct from the G. plicifera-G. siiicula complex. However, this complex needs to be re-evaluated as a group in order to determine interrelationships. LITERATURE CITED Bailey, J. L., R. Pearl and C. P. Winsor. 1932. Variation in Goniobasis rnrginica and Anculosa carinata under natural conditions. Biol. Gen. Band 8:607-634. Branson, B. A. 1977. Fresh water and terrestrial Mollusca of the Olympic Peninsula, Washing^ton. The Veliger 19:310-330. Goodrich, C. 1935. A species of Goniobasis new to the Great Basin. Th£ Nautilus 49:66. 1937. Goniobasis columiriensis Whiteaves. The Nautilus 50:82-84. 1942. The Pleuroceridae of the Pacific Coastal drainage, including the Western Interior Basin. Oec. Pap. Mus. Zool. U. Mifh. 469:1-4. 1944. Pleuroceridae of the Great Basin. Occ. Pap. Mus. Zool. U. Mich. 485:1-4. Henderson, J. 1932. The range of Polygyra and of Gonio- basis in California. The Nautilus 46:4-6. 1935a. West American species of Goniobasis, with descriptions of new forms. The Nautilus 48:94-99. 1935b. West American species of Goniobasis, with descriptions of new forms. The Nautilus 48:130-134. 1935c. Fossil non-marine Mollusca of North America. Geol. Soc. Amer. Spec. Pap. 3:225-231. Walker, B. 1900. Changes with growth of Lithasia oboimta (Say). The Nautilus 13:97-98. Wiebe, A. H. 1926. Variations in the fresh water snail, Goniobasis livesce7is. Ohio J. Set. 26:49-68. Specimen Shells Offering microscopic and miniature (to "t inch) .shells from the Florida Keys, with accurate locality data Al.'m unsorted grunge: write for list. Margaret Teskey P.O. Box 273 Big Pine Key. Fl. 330J,3 PHILLIP W. CLOVER COLLECTOR & DEALER IN WORLD WIDE SPECIMEN SEA SHELLS p. O. Box 83 Glen Ellen, CA 9S442 FREE SHELL LISTS SPECIALISTS IN CYPRAEA^ CONUS^ VOLUTA margineLla, Mif RA, MUREX 20 THE NAUTILUS January 29, 1981 Vol. 95(1) A NEW RECORD OF VALVATA SINCERA ONTARIENSIS F. C. BAKER FROM MINNESOTA Robert C. Bright Bell Museum of Natural History University of Minnesota Minneapolis, Minnesota During the summer of 1970 a large series of mollusk and seed samples were obtained from the surface of sediments of lakes and ponds in northern Minnesota by Hilary Birks. One sam- ple, from Little Spring Lake, Lake County, con- tained a specimen of the rare Valvata sincera forma ontariensis F. C. Baker. Although the specimen is damagaed (part of the apex is missing, as is the terminal portion of the shell beneath the periostracum) it exhibits the loose coiling, round entire aperture, wide umbilicus, and the sharp, thin, lamellar ribs of the periostracum described by Baker (1931). The periostracal lamellae are fairly evenly spaced and most are directed posteriorly. With the periostracum removed, the shell would appear much like the form described by LaRoque (The Nautilis 46: p. 199) as V. I. mccolli from the late Wisconsin marl in Grey County, Ontario, Canada. I agree with Clarke (Malacologia 13: p. 225) that mccolli is a synonym of ontarwvsis but consider them to be forma, rather than true subspecies. Little Spring Lake is located in a spruce forest in SWV4, sec. 29, T61N, RlOW, about 20 miles southeast of Ely, Minnesota. The lake is small, being about 300 yards long and 150 yards wide. It is densely vegetated except for an open space in the east end, where the maximum depth at- tained is 11 feet. The specimen was collected about five yards offshore at the western end of the lake in about two feet of water. There the vegetation was dense (ca. 80 percent cover) and was dominated by Nymphaea odorata, Nuphar variegatum, Potamogeton (3 spp.), Najasflexilis. and Megalodonta beckii. Other mollusks taken from the bottom nearby include Marstonia decepta, Valvata tricarinata, Gyraulus parvits, Valvata sincera, Sphaerium sp., and Pisidium sp. The bottom sediments were fine-grained and muddy. The only previously published records of on- tariensis are from Ontario, Canada. The plate photographs were provided by Roger Woo. Hilary Birks (Cambridge University) provided the habitat data. REFERENCES CITED Baker, F. C. 19.31. Description of a new variety of Valvata ieunsi Currier. The Nautilus 44:119. Clark, A. H. 1973. The freshwater mollusks of the Canadian Interior Basin. Malacologia 13(l-2):225. LaRoque, A. 1932. A new variety of Valvata lewisi from the Pleistocene of Ontario. Can. Field Naturalist 46(9):199. FIG. 1. Apical view o/ Valvata sincera /orma ontariensis, Bell MNH No. P3578. xi5. FIG. 2. Apertural view of the same .•specimen. The terminal portion of the last whorl is slightly distorted because the shell is mv^sing beneath the periostracum. x 15 Vol. 95 (1) January 29, 1981 THE NAUTILUS 21 THE FRESHWATER NAIADS OF ELK RIVER, WEST VIRGINIA WITH A COMPARISON OF EARLIER COLLECTIONS Ralph W. Taylor and Romie C. Hughart Department of Biology Sciences Marshall University Huntington, WV 25701 ABSTRACT During the summers of 1978 and 1979 an extensive surtjey of the freshwater mussels of the Elk River was conducted. A total of eighteen species ofunionacean clams, plus the exotic Asian clam, Corbicula fluminea, were collected. A search of the collections of several miiseums produced evidence that earlier workers had, over the last one hundred years, taken a total of twenty-07ie species from the Elk River. Lampsilis orbiculata, Dysnomia torulosa rangiana, Cyclonaias tuber- culata and Lampsilis ovata, which had been reported earlier, were not found and m.ust be presurned no longer present in the Elk. Corbicula fluminea has spread throughout the Elk River. Fusconaia m. maculata, Lampsilis radiata luteola. Elliptic dilatata, Ptychobranchus fasciolaris and Actinonaias ligamentina carinata are presently the dominant species. Information on the freshwater naiads in- habiting the streams of West Virginia is all but non-existent. Until recently, the poor roads and rugged terrain of the region have made it rather difficult to reach most parts of the state. A few hardy individuals, most notably Dr. A. E. Ort- mann, carried out limited expeditions into the state around the turn of the century. Other less well-known biologists have collected in West Virginia but none of their work was published, even though, fortunately, some of their material was deposited in museums around the country. Contemporary papers by Morris and Taylor (1979) and Taylor (1980) report mussel faunas of the Kanawha and Ohio Rivers, respectively. David Stansbery and Carol Stein (Ohio State University Museum of Zoology) have collected extensively throughout West Virginia in recent years but none of their work has as yet been published. We shall in this paper report material collected in the Elk River during the summers of 1978 and 1979, and in addition compare and con- trast our findings with those of other investi- gators. We believe this to be the first extensive survey to have been carried out on the Elk. THE ELK RIVER The Elk River orginates in a sparsely pop- ulated mountainous area in Pocahontas County, W. Va., and flows approximately due west for 181 miles to its confluence with the Kanawha River at Charleston, W. Va. It traverses valleys with steep, high walls. Most of the basin is heavi- ly forested and remains essentially untainted by man. The only pollutants present are those orig- inating in a few local industries and a small amount of human sewage. The actual amount of raw sewage discharged into the stream is not known, but it probably has a significant effect on such water quality parameters as bacterial county, plant nutrients and turbidity (W. Va. (Geological and Economic Survey, 1973). There are no major cities in the Elk River basin, and mining and timbering activity is limited, hence the Elk is a stream of fairly high quality. The bottom substrate consists primarily of cobble, silt and sand. The main stem of the Elk averages a fall of 168 feet per mile. The best collecting is in or near shoal areas. The river, throughout most of the collecting area, averaged 50 meters in width and less than two meters in depth. METHODS Shells were hand-picked from the shallows and river banks. Only live specimens, or those which obviously had been recently killed, were 22 THE NAUTILUS January 29, 1981 Vol. 95(1) collected. Specimens were returned to the lab- oratory where they were cleaned, positively identified and accessioned in to the Marshall University Malacological Collections. Voucher specimens have been placed with the Ohio State University Museum of Zoology. All scientific names used in this paper are those currently be- ing used by Stansbery (1979). A total of 15 localities were designated as collecting sites and visited at irregular intervals during the two summers. COLLECTING SITES Site 1 60 yards down river from the base of Sutton Dam, near Sutton (Braxton County) Site 2 along Rt. 16, 7.5 miles east of the Brax- ton/Clay County line (Braxton County) Site 3 along Rt. 16, 3.2 miles west of the Brax- ton/Clay County line (Clay County) Site 4 near a small roadside park on Rt. 16, 15.3 miles west of the Braxton/Clay County line (Clay County) Site 5 along Rt. 16, 15.9 miles west of the Braxton/Clay County line (Clay County) Site 6 Secondary Rd. 5, 4.3 miles west of in- tersection with Rt. 16 (Clay County) Site 7 Secondary Rd. 5, 4.8 miles west of the intersection with Rt. 16 (Clay County) Site 8 Secondary Rd. 5, 6.4 miles west of the intersection with Rt. 16 (Clay County) Site 9 Secondary Rd. 5, near Camp Elk, 8.3 miles west of the intersection with Rt. 16 (Clay County) Site 10 Secondary Rd. 5, downstream of Camp Elk, 8.7 miles west of the intersection with Rt. 16 (Clay County) Site 11 Secondary Rd. 5, 3.0 miles east of the intersection with Rt. 4 (Clay County) Site 12 Secondary Rd. 5, 2.4 miles east of the intersection with Rt. 4 (Clay County) Site 13 small roadside park on Rt. 4 at the Clay/Kanawha County line Site 14 below the bridge at Queen Shoals (Kanawha County) Site 15 along U.S. 119 southeast of the Rt. 4 -U.S. 119 intersection at Clendenin (Kanawha County) RESULTS A total of 18 species of unionacean clams, plus the exotic Asian clam Corbicula harm, were col- lected. These data are presented in Table 1. All collecting sites, with the execption of Site 1 (im- mediately below Sutton Dam), produced some usable material. In order to get the most information available on previous collections made in the Elk River, the first author visited several museums (spring 1980) and searched the holdings for West Vir- ginia material. The museums visited were as follows: Field Museum of Natural History - Chicago U.S. National Museum -Washington, D.C. Carnegie Museum (Car. I.)- Pittsburgh Ohio State University Museum of Zoology (OSU)- Columbus Harvard University Museum of Compara- tive Zoology (MCZ)- Boston The results of this search are presented in Table 2. Elk River specimens were found at the Ohio State University Museum, the Carnegie In- stitute Museum and the Harvard University Museum of Comparative Zoology. In all, 21 species of unionids have been col- lected in the Elk River by earlier investigators. The vast majority of the museum material was collected 50 to 100 years ago, with most of the work having been done by Dr. A. E. Ortmann of the Carnegie Institute. The only contempory report on the mussels of the Elk River was by Bates (1971). This paper was based on limited collecting (two localities - single collection at each) and listed only eight species. The species found by Bates were: Ellip- tio dilatata, Fusconaia jlava. Quadrula pustu- hsa, Adinonaias l. carinata, Lampsilis fas- ciola, Lampsilis ventricosa, Ligumia recta and Oboi'aria subrotunda. With the exception of Quadrula pustulosa all species that Bates reported had been previously collected and were found in the museum collections. In this paper we report Lampsilis radiata luteola { = Lampsilis siliquoidea) for the first time as appearing in the Elk River. This species, while never occurring in large numbers at any one site, nevertheless is quite widespread and was collected at 11 of the 15 designated sites. Also reported for the first time in the Elk River is the exotic Asian import Corbicula Vol. 95(1) January 29, 1981 THE NAUTILUS 23 Table 1. Abundance and distribution uf Elk River Mussels (R = Rare, M = Moderately Common, C = Very Common). Species Strophi tus u. undulatus (R) Lasmigona costata (M) Quadrula £. pustulosa (R) Amblema p . pi i cat a ( M ) Fusconaia tn. maculata (C) Fusconaia f lava ( R) Pleurobema clava (R) Pleurobema sintoxia ( R) Ell ipt lo crassidens ( R) EllipUu dilatata (C) Ptychobrttnuhus fasciolaris (C ) Act monaias 1 . carinata ( C ) Obovaria subrotunda (C ) Ligumia recta (C) Villusa ins I R) Lamps 1 lis r . luteola ( C ) Lampsilis vent ricosa (C ) Lampsilis fasciola ( R ) Curbicuia leana ( C ) Site No. 7 8 9 10 11 X 12 13 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Table 2. Museum records from the Elk River (locality data are as they were recorded on original tags). Species Strophitus u. undulatus Alasmidonta marginata Lasmigona costata Amblema p. plicata Fusconaia m. maculata Locality Gassaway Shelton Clay Sutton Gassaway Shelton Sutton Shelton Gassaway Mouth O'Brien Ck, Below Sutton Dam Mouth Twistabout Ck. .2 mi. below Little Sandy Ck. Sutton Gassaway Shelton Below Queen Shoals Bridge Mouth of Laurel Ck. Below Sutton Dam Below King Shoals Run Gassaway Mouth O'Brien Ck. Museum Catalog No Car. 61 .5397 Car. 61.5399 Car. 61.5398 Car. 61.5395 Car. 61.5382 Car. 61.5333 Car. 61.5366 Car. 61.5368 Car. 61.5367 OSU 6514 OSU 24702 OSU 6420 OSU 23112 Car. I. 61.5262 Car. I. 61.5265 Car. I. 61.5266 OSU 23227 OSU 6411 OSU 24703 OSU 44379 OSU 45026 OSU 45013 24 THE NAUTILUS January 29, 1981 Vol. 95(1) Fusconaia flava Cyclonaias tuberculata Pleurobema clava Below mouth Little Sandy Ck. Below Blue Ck. bridge Mouth Twistabout Ck. Mouth Twistabout Ck. Mouth O'Brien Ck. Rt. 11 bridge N.E. of Clay Frame town Glendon Elkhurst Rt. 6') bridge 2 mi. N.W. of Kelso Mouth Twistabout Ck. 5.8 mi. W. of Fayetteville Mouth O'Brien Ck. Below Sutton Dam Mouth Buffalo Ck. 1 mi . N.E. of Clay Frametown Gassaway Above Twistabout Ck. 01 endon Shelton Gassaway Sutton OSU 23113 osu 23034 OSU 7901 OSU 6418 osu 6513 OSU 44650 OSU 44993 OSU 44976 OSU 44931 OSU 24996 OSU 7905 Car. I. 61.5301 OSU 6516 OSU 24704 OSU 44651 OSU 44551 OSU 44999 OSU 45027 OSU 43882 OSU 44977 Car. I. 61.5325 Car. I. 61.5324 Car. I. 61.5323 Pleurobema sintoxia At Twistabout Ck. OSU 43883 Elliptio crassidens Ptychobranchus fasciolaris Actinonaias 1 . carinata Obovaria subrotunda Truncilla truncata Ligumia recta Villosa i. iris .2 mi. below Queen Shoals Frametown Glendon Gassaway Gassaway Shelton Sutton Clay 1 mi. N. of Clay Above Twistabout Ck. Above Twistabout Ck. Shelton Shelton Sutton Gassaway 1 mi. N. of Clay Shelton Gassaway Below Sutton Uam Rt . 64 bridge 4 mi . E. Fayetteville Mouth O'Brien Ck. U.S. Rt. 64 bridge E. of Fayetteville Mouth O'Brien Ck. Mouth Twistabout Ck. Shelton Clay Gassaway Above Twistabout Ck. Elkhurst 1 mi. N.E. of Clay Mouth Buffalo Ck. 5 mi . E. of Fayetteville Shelton Sutton OSU 23228 OSU 45000 OSU 44978 Car. I. 61.5327 Car. I. 61.5339 Car. I. 61.5328 Car. I. 61.5335 Car. I. 61.5340 MC2 185594 OSU 6424 OSU 7910 Car. I. 61.5410 Car. I. 61 .5411 Car. I. 61 .5406 MCZ 262800 MCZ 185596 Car. I. 61.5451 Car. I. 61.5449 OSU 24706 OSU 16182 OSU 6527 OSU 19062 OSU 6521 OSU 7913 Car. I. 61.5504 Car. I. 61.5503 Car. I. 61 .5502 OSU 43890 OSU 44938 OSU 44558 OSU 44668 OSU 19066 Car. I. 61.5493 Car. I . 61.5492 Vol. 95(1) January 29, 1981 THE NAUTILUS 25 Species Locality Lampsilis ventncosa 1 mi. N. of Clay Gassaway Shelton Gassaway Sutton Clay City Lampsilis orbiculata . 5 mi . below moul Lampsilis ovata Shelton Clay Lampsilis fasciola Gassaway Mouth O'Brien Ck Epioblasma turulosa rangiana Elkhurst Mouth O'Brien Ck Mouth O'Brien Ck Museum Catalog No. MCZ 185597 MCZ 262794 Car. I. 61.5538 Car. I. 61.5536 Car. I. 61.5535 Car. I. 61.5537 OSU 44386 Car. I. 61.5527 Car. I. 61.5526 MCZ 262795 OSU 45024 OSU 44962 OSU 6526 OSU 45025 JJuminea (also referred to as manilensis Philippi and leana Prime). Thomas and Mackenthun (1964) were the first to recognize Corhicula in the Kanawha River at Charleston, W. Va. near the mouth of the Elk River. It has since spread into the Elk and is presently distributed throughout our study area as far upstream as Sutton Dam. Of the 21 species reported by earlier investi- gators, we did not find the following six: Alas- midonta marginata, Cyclonaias tuberculata, Epioblasma torulosa rangiana, Lainpsilis orbi- culata, Lampsilis ovata and TriinHlla truncata. The Elk River is a stream of fairly good quali- ty and is at the present time supporting a good population composed of a relatively large number of kinds of unionid mussels. Fusconaia m. maculata, Lampsilis r. luteola, Elliptio dilatata, Ptychobranchns fasciolaris and Ac- tinonaias I. carinata are the dominant species in the Elk River. Only two specimens of Pleuro- beyna clava were found in the entire study. This species is very nearly extinct in this river at this time, while fairly large collections of it were made 50 years ago. A single fresh specimen of Elliptio crassidens was found. It is our belief that this species is also in danger of extinction in the Elk River in the very near future. ACKNOWLEDGMENTS Special thanks to the museum curators who so graciously opened the collections to me. To the many others associated with the museums, I ex- tend my heartfelt appreciation (R. W. Taylor). Some of the material presented in this paper was submitted by the second author to the Biological Sciences Department at Marshall University as partial fulfillment of the re- quirements for the Master of Science Degree. LITERATURE CITED Bates, J. M. 1971. Mussel Investigations of the State of West Virginia. U. S. Bureau of Commercial Fisheries. 91 pp. Morris, J. S. and R. W. Taylor. 1979. A Survey of the Fresh- water Mussels of the Kanawha River of West Virginia. TJw Nautilus 92{4):\53-l55. Stansbery, D. H. 1979. Naiad Mollusks of the Ohio River Drainage System. The Ohio State University Museum of Zoology (mimeographed). 1 p. Taylor, R. W. 1980. A Sunvy of the Freshwater Mussels of the Ohio River from Greenup Locks and Dam to Pitts- burgh, Pa. U.S. Army Corps of Engineers, Huntington/ Pittsburgh Districts. 71 pp. Thomas, N. A. and K. M. Mackenthun. 1964. Asiatic Clam Infestation at Charleston, West Virginia. The Nautilus 78(1):28. West Virginia Geologic and Economic Survey. 1973. The Elk River Basin: A Report on Water Pollution in the Elk River and Its Tributaries. 39 pp. 26 THE NAUTILUS January 29, 1981 Vol. 95 (1) NEW RECORDS OF ALLOP.OSUS MOLLIS VERRILL (CEPHALOPODA, OCTOPODA) FROM THE PACIFIC OCEAN Angeles Alvarino and John R. Hunter National Oceanic and Atmospheric Administration National Marine Fisheries Service Southwest Fisheries Center La Jolla, California 92038 ABSTRACT Two specimens o/ Alloposus mollis (Alloposidae) captured off southern Califor- nia are described and illustrated. The anatomical characteristics of the species are discussed, and its distribution is reviewed. Alloposv^s mollis is a relative rarely captured mesopelagic cephalopod. Records of this species are few and locations scattered. The published illustrations and descriptions are rather in- complete and diagrammatic because of the lack of specimens in good condition of preservation. Verrill (1880) originally described the species from specimens collected off New England in the North Atlantic. Additional specimens were reported by Verrill (1881) and Hoyle (1886) from off Newport, Rhode Island, the mouth of the Chesapeake Bay, and in other parts of the Atlantic (Joubin, 1895, 1900; Robson, 1930 for his A. hardyi; Thore, 1949; Adam, 1960). Ijima and Ikeda (1902) described an allied species, A. pacificus, from the Sagami Sea, Japan, and this species was recorded also for Sagami Bay, Japan, by Sasaki (1929). Berry (1914) suggested that the evidence was not sufficient to warrant two different species. Similarly, A. hardyi is believed to be synonymous with A. mollis (Thore, 1949). Specimens belonging to the fami- ly Alloposidae obtained at Pailolo Channel, Hawaii and other ALBATROSS stations in the Pacific (Hoyle, 1904; Berry, 1914) were con- sidered to belong to A. mollis. Alloposidae material from the DANA collections, including specimens from the Atlantic, Indo-Pacific (05°52'N, 131°14'E) and the Indian Ocean (04°52'N, 77°08'E), were placed by Thore (1949) under A. mollis. Young (1972) obtained one specimen from Santa Catalina Basin, California (33°23'N, 118°49'W). This specimen, judging from the illustrations, was not complete and in bad condition of preservation, facts also explain- ed by Young (1972) when he comments ". . . very large, but rather poorly preserved specimen". Two specimens of A. mollis in excellent condi- tion were taken off the southern California coast during survey cruises conducted by the National Marine Fisheries Service's R/V DAVID STARR JORDAN. These records to- gether with the one by Young (1972) are the first reported specimens obtained from the North American Pacific. This report documents these records, provides a description and il- lustration of the specimens and review, the distribution and external morphology of the species. Alloposus mollis Verrill, 1880 Material examined -The specimens collected were: Specimen A (200 mm total length, head and mantle) captured July 18, 1976 (2349 hours PST) at 33°23'N, 117°43'W in a six feet Isaacs- Kidd midwater trawl towed to a maximum depth of 70 m; and Specimen B (67 mm total length, head and mantle to base of arms) col- lected March 24, 1977 (0410 hours PST) at 33°31.8'N, 117°58'W, in a midwater trawl tow- ed at a maximum depth of 7 m. Both specimens were females. Description -These animals are ovoid in shape, widest at the head region. They are soft and of smooth gelatinous consistency, translu- cent, and covered with small red spots, giving the whole animal a brick-purple color. The head is large, short and slightly broader than the body. The mantle opening is wide and full, and in two broad pouches, extending dorsally from Vol. 95 (1) January 29, 1981 THE NAUTILUS 27 FIG. 1. A-Lateral left m.eu> o/A]loposus mollis (Specimen Bl: B-Dorso lateral left mew o/"Allopo- sus mollis (Specimen B). the ventral point of the commissure towards the level of the eyes (Fig. 1). The eyes are large and prominent, covered by the eye lid. The lid has a small central opening which can be expanded to expose the entire eye (Figs. 2A and 2B). The funnel is large and is embedded with the gela- tinous tissue of the head, except for the top which is free, reaching to a level higher than the upper edge of the eyes. The olfactory organ, a flat round lump, is located posteriorly to the eyes. The arms are stout and short, relative to the body length (head and mantle), and they de- crease in length from the dorsal to the ventral side. They are connected at the base by a broad membrane, web or umbrella, which attains the greatest extension between the dorsal pair of arms. The suckers are arranged in a straight row of 3 to 4 (ventral arms) or 4 to 6 (dorsal arms), from the mouth to the point on the arm where the web starts. At this point the suckers begin to deviate from a straight course to an in- cipient zig zag arrangement, which becomes more evident along the webbed and the free part of the arms (Fig. 2C). This pattern occurs in both specimens we collected, in Verrill's syn- type, and in all other specimens we received from the Division of Mollusks at the Smithso- nian Institution, which included the material ex- amined by Berry (1914). Measurements from our specimens are given in Table 1. DiscMssiori- The arrangement of the suckers on the arms is an important character and sub- ject to some disagreement and confusion in the literature. Ijima and Ikeda (1902) described an allied species, A. pacificus. from the Sagami Sea, subsequently reported by Sasaki (1929) from the same body of water in the Sagami Bay, Japan. Berry (1914) stated that the anatomical differences between A. pacificus and A. mollis were insufficient to establish a new species. Ac- cording to Ijima and Ikeda (1902) the suckers of A. pacificus were arranged in a single row for most of the length of the arm, and were biserial- ly arranged only on the free part of the arm, that is, from the edge of the web to the outer tip of the arm. This same characteristic was men- tioned by Robson (1930) for A. hardyi. Verrill (1880) specifies that the suckers are "large, single, in two alternating rows," and Verrill 28 THE NAUTILUS January 29, 1981 Vol. 95(1) (I4 (2 a. FIG. 2 . A - Eye urith the eyelid exparwfed, exposing the eye (Specimen Al: B - Righ t eye with sphineier of eyelid contracted; the diameter of the opening corresponds to that of the pupil of the eye (Specimen B); C- Detail of the crown of arms and. interarms web, and the disposition of the siwkers of female Alloposus mollis (from both Specimen A and Specimen B). (1881) states that the suckers "are in two rows or rather in a single more or less zig zag row which most conspicuously approached the two rowed condition after reaching the margin of the umbrella (at about the 13th sucker on the dorsal arms)." Robson (1930) explained for A. hardyi that "suckers tend to be uniserial or very widely alternating except about or just beyond the margin of the web, where they are more or less biserial." The suckers in our specimens are arranged, as explained above, in a straight row from the mouth to the point where the web starts, and at this point the suckers initiate an incipient zig zag arrangement, which becomes clearly evident along the webbed and free part of the arms (Fig. 2C). The suckers are 1 to 12 mm in diameter and their number varies from 12 (Thore, 1949) to 155 per arm (Joubin, 1900). The proportions of the body in A. mollis change slightly with age; older specimens have relatively shorter bodies and longer arms than young individuals. The only sexual dimorphism in Alloposidae is the third right arm, hectotylus of males. The males have 7 normal arms and the hectotylized arm. Verrill (1881) reported a hectotylus reach- ing 200 mm in length and 20 mm in width, with two rows of large 4-mm diameter, 6 or 7 lobed suckers, with a terminal process 30 mm long and 7 mm diameter. Most of the specimens of A. mollis obtained by other authors were partially destroyed, injured during trawling, or only fragments of large in- dividuals. Our specimens were alive and in ex- cellent condition when brought on deck, and the morphological structures were accurately main- tained (Fig. 3). No dissections were made to ex- amine the internal atatomy or stomach content, because we felt it was important to keep the specimens in good conditon. Vol. 95 (1) January 29, 1981 THE NAUTILUS 29 TABLE 1. Meristic data on the specimens o/Alloposus mollis collected off California. Total length fim Width nm Head width run Length funnel nin Eye diameter nm Diameter open, eye lid Width mantle nm No. suckers run Size suckers nm Specimen A 200 65 76 36 26 3 80 >80 3 to 1 Total length of arms from ventral to dorsal right left I 82 76 II 88 82 III 92 85 IV 120 117 Length of free part of the arms right left I 43 40 II 40 37 III 52 50 IV 85 82 Specimen B 67 38 40 16 8 1 42 20-30 1.5 to <1 Total length of arms from ventral to dorsal right left I 24 20 II 35 32 III 36 34 IV 40 40 Length of free part of the arms right left I 12 10 II 15 15 III 18 17 IV 22 22 FIG. 3. Alloposus mollis (Specimen B), length 67 mm. Distribution -Alloposus mollis is a cosmopol- itan species, usually found near tropical and sub- tropical oceanic regions (Tables 2 and 3; Fig. 4). The majority of the deep-sea cephalopods were collected in trawls and probably are adept at avoiding nets of all types. The capture of our specimen B (Fig. 3) was observed by biologists on deck of vessel, and it was efficiently avoiding capture, when net was directly towed in pursuit of the specimen. Similarly, Thore (1949) sug- gested thati4. mollis may only appear to be rare because of their ability to avoid capture. A. mollis may inhabit the open sea during certain phases of its life cycle, and remain in deep and bottom layers of the continental slope during other (Thore; 1949). Our specimens were both juvenile females 30 THE NAUTILUS Januai^- 29. 19S1 Vol. 95(1) TIDT r -T ■■ •,'"" ycv'.ii •izt:2 r^, .-L »•«■•«. Ts . 2S"-3S1 ir.; ^S'STt. r-,6 . ■erst. ■;'■ • B-JTl. ' ;"*€ • irjTi. r-.; • a':5 « 05"a-s. I3i*I4': 5«*a-i, TTTi-- ?rwi. 08"S9I Lails Ofrtu, -aar'ai 1.. u^ *1? 40S ■r r- f? is.t7c- ?s "" -- i-t '. as '.' 5"t= «. r'a: • Jjc-sj" 35-U «. "^'3 • S'36 1, •'.•=- . , E"J« 1. "•■ " t ■f. m »H aiger .i-3e iFT %. -y^ 1 ■ ; - - i^V X- a: IT ;'. ..-.rr -.-■ I^zr.-. '•^'-.■■j^ : 1-.: iCm -f. m 3CB IQh n '- Is— •■. 'S- ya«. i^, i: • sr^-t. ^ -^ • (;— - . iSJ lcr=i i::«m -c?e. "sse «r»5 «. ST : . t3 ■': zC zz ' : H n-2-i. »j"a-ii -co:-^. "=St r"s 1. j-u . ir>. m: -_z 'j: s iir-jL%. ■£'-a. • ■St larr z^ j-c Jci^i. '^X ;i;A-!r :*i .!>;- ana TTser-^a'".. •ai"i41. 3f3« • -0-. -.:. I «e-37 :"• I'ter-at'tg. | i-'cact.zei'cnc «-- r 1 :* wee , arer z • 15 « 31 -Z 2-3., 2S.2 1 1 23 MS ;■ i? ■ I. "■: A^. irsc ,0.3 II 33 . 14 II J3 • 17 I « 33 ■ il:r Sara C.- ?r. i 3S n aoo- Um. 1560 1 ■: 12£ T2C rx 38 F foufiq, 1972 1 Vol. 95 (1) Januarj' 29, 1981 THE NAUTILUS 31 TABLE 3. Data im specimens fmm the Smithstmian Institution. of lenc"- soeciinens nr =osit ion Depth Date I rele 12 j I » 60 4 males variab Is I • 120 1 » 55 Several * med ium 2 * 55 I * large I * ^5 I * S8 59 *52' K-~C*55 ' ft icTT Knooe isianc) coC Hawaiian Islands (Pai lolo Channel ) 530. ■i 2I°06'N-I56°I3'W (Hawaiian Islands ) 586 21°0rN-l56°43'W (Hawaiian Islands) 5^.7 12°24'N-82°2i'W (Caricbean Sea ) 28°I7'N-86°2!'W ( Gulf of Mexico ) IB°52'N-94=50'W ( Gulf of Mexico ) 2i^i'N-S7=49'W ( Gulf of Mexico ) 23°CiO'N-35°20'W ( Gulf of Mexico ) 29=46'N-38°25'W ( Gulf of Mexico ) 612.7 671 612.7 567 521 36.5 22 July, 1902 5 Apr! 1, 1 968 17 Nc^., 1968 22 Nov., 1968 20 June, 1959 5 June, 1970 U Aug., 1970 27 Aug., 1970 U A^r;i,l972 * Due TO bad condition of preservation of sceci-ens, sex could nc" Total lencth induces -eac and nanrle. • PUBLISHED RECORDS X PRESENT DATA o SPECIMENS FROM THE SMITHSONIAN INST. FIG. 4. Distribution o/Alloposus mollis. 32 THE NAUTILUS January 29, 1981 Vol. 95(1) (200 mm and H7 mm in total length) and were taken at 70 m and 7 m depth respectively. Ac- cording to Verrill (1881) the bathymetric range of the species extends to 2462 m depth, and fragments of specimens were taken from 3173 m depth. Berry (1914) states that it extends from 180 m to more than 900 m depth. Voss (1967) explains that Alloposidae appear to be distributed in the upper 400 m, although they may extend to more than 3000 m depth, and that larvae and juveniles occur in the upper 100 m. Populations of A. mollis probably are strati- fied ontogenically, as is often the case in oceanic animals. The temperature of the surface waters at the time of capture of our two specimens was 14.6°C (Specimen A), and 13.0°C (Specimen B), which is well within the range of temperature recorded for the species (Thore, 1949). Cephalopods are important in the food web of the oceans, as they constitute the main food of dolphins, sperm whales, other sea mammals, turtles, Thunnidae, sharks and other large fish. Joubin (1895, 1900) found fragments of A. mollis (dorsal region and tentacular crown) in a region of the Atlantic where sperm whales were feeding, but found no A. mollis in their stomachs, possibly because of the difficulty in identifying digested gelatinous remains. ACKNOWLEDGMENTS We would like to extend our appreciation to Dr. Joseph Rosewater and Michael J. Sweeney, Division of Mollusks, Smithsonian Institution, for providing us for comparative analysis the syntype and good amount of material of Allo- posus mollis. We are also grateful to Carol A. Kimbrell for obtaining Specimen A, here stud- ied, from the trawl collections at the Southwest Fisheries Center, to Daniel L. Gittings (Li- brarian, SWFC) and Nelson Ross (NODC) for their great cooperation in providing us with valuable literature pertinent to this subject. We also like to thank Roy M. Allen for the prepara- tion of the distributional map. LITERATURE CITED Adam, W. 1960. Les Cephalopodes de L' Institut Fran^ais d'Afrique Noire. Pt. II. Bull. Inst. Frangais Afriqiie Noire, Ser. A (2):465-511. Berry, S. S. 1909. Diagnoses of new Cephalopodes from the Hawaiian Islands. Proc. U.S. Natl. Mus. 37(1713): 407-419. 1914. The Cephalopoda of the Hawaiian Islands. Bull. Bur. Comm. Fish. 32(1912):255-362. Hoyle, W. E. 1886. Report on the Cephalopoda collected by H. M. S. Challenger during the years 1873-1876. IN: Voy- age of the Challenger, 16:I-VI, 1-246. 1904. Reports on the dredging operations off the west coast of Central America, by the R/V Albatross (1899-1900). VI Report on the Cephalopoda collected by the research vessel Albatross. Bull. Mas. Comp. Zool. Harvard College 43:1-71. Ijima, I. and S. Ikeda. 1902. Notes on a specimen of Amphi- tretus obtained in the Sagami Sea. Annot. Zool. Japan 4:85-101. Joubin, L. 1895. Contribution a I'etude des Cephalopodes de I'Atlantique Nord. Resultats des Campagnes Scientifiques Prince de IMonaco, (9): 1-63. 1900. Cephalopodes provenant des campagnes de la PRINCESS-ALICE (1891-1897). Resultats des Campagnes Scientifiques Prince de Monaco, 1889, 17: 1-135. Robson, G. S. 1930. Cephalopoda. Discovery Rep. 2: 371-402. Sasaki, M. 1929. A monograph of the Dibranchiata Cephalo- pods of the Japanese and adjacent waters. Jour. Fac. Agric. Hokkaido Univ., Sapporo, Japan, Suppl. 20:1-357. Thore, S. 1949. Investigations on the DANA Octopoda. Part i. Bolitaenidae, Amphitretidae, Vitreledonellidae and Alloposidae. Dana Report 33:1-85. Verrill, A. E. 1880. Notice on the remarkable marine fauna occupying the outer banks off the southern coast of New England. Anwr. Jour. Sci. Ser. 3, 20:390-403. 1881. Reports on the results of the dredging under the supervision of A. Agassiz. Report on cephalo- pods and some additional species dredged by the U.S. Fish Commission steamer FISH HAWK, during the season of 1880. Bull. Mus. Cmnp. Zool. Harvard College 8:99-116. 1884. Second catalogue of mollusca recently added to the fauna of New England coast and adjacent part of the Atlantic, consisting mostly of deep sea species, with notes on others previously recorded. Trans. Conn. Acad. Sci. 6:139-294. Voss, G. L. 1967. The biology and bathymetric distribution of deep-sea cephalopods. Studies Trap. Oceanogr. 5: 511-535. Young, R. E. 1972. The Systematics and areal distribution of pelagic Cephalopods from the Seas off southern Cali- fornia. Smithsonian Contrib. Zool. 97:1-108. Vol. 95(1) January 29, 1981 THE NAUTILUS 33 VERTIGO MERAMECENSIS (PULMONATA: PUPILLIDAE) FROM THE NIAGARAN ESCARPMENT, IOWA Terrence J. Frest and Leslie P. Fay Department of Geology The University of Iowa Iowa City, Iowa 52242 ABSTRACT The snail. Vertigo meramecensis Van DevendeT was found at four' localities along the Niagaran Escaryynent in Fayette, Clayton, arid Dubuque Counties, Iowa. Though more variable in morphology than originally reported, the species is easily distinguishable from V. gouldi with which it occurs. In Iowa, V. mera- mecensis inhabits steep, damp, well-forested talus slopes with extensive calcare- ous rock outcrops. Vertigo meramecensis was recently described from the Northern Ozark Plateau (Crawford County, Missouri) with sixteen individuals con- stituting the type series (Van Devender, 1979). Recent collecting in northeastern Iowa has turn- ed up about fifty more individuals from four localities in Fayette, Clayton, and Dubuque Counties (Fig. 1). Two of these are drift collec- tions but the species was collected alive at the two other sites (localities 3 and 4) in 1975 and 1979. Small litter samples were also taken in August, 1979 at both localities to insure ade- quate representation of all land snail species. The Iowa collections materially enlarge the range of V. meramecensis and provide much ad- ditional information on the species' morphology and ecological requirements (discussed below). Van Devender's full description is confirmed in essentially all respects by our material. Though the species is closely related to the notoriously variable V. goiddi gouldi (Binney) (see Pilsbry, 1948), which is common in collections from all four localities, we encountered little difficulty in separating adult specimens of meramecensis from gouldi, even without recourse to a micro- scope or hand lens. The Iowa localities are more than 300 miles to the north of the type locality. All four are situated on the Niagaran Escarpment of north- eastern Iowa, a well dissected area with steep, heavily wooded bluffs unsuited for farming and with extensive outcrops of Silurian limestones FIG. 1. Map uf part of central United States showing knoum distribution of Vertigo meramecensis Van Devender. and dolomites (Kankakee, Edgewood, and Hop- kinton Formations). All are within a few miles of the Iowa portion of the Driftless Area, a region long known to harbor unusual land mollusks (Imlay, 1973). This portion of Iowa historically was among the most densely forested areas in a largely prairie state, and because of its rugged 34 THE NAUTILUS January 29, 1981 Vol. 95 (1) topography is probably the least disturbed by agriculture (Hartley, 1966). Suitable habitat for V. meramecensu in Iowa is likely limited to the eastern third of the state and, possibly, the Loess Hills of extreme west- ern Iowa. However, brief searches in the most nearly ecologically equivalent areas in Fremont, Boone, Linn, Johnson, and Lee Counties failed to produce any specimens, and many north- eastern Iowa localities also lack the species. Although obviously much more work needs to be done on its distribution, it is probable that V. meramecensis will prove to be rare and very local in occurrence in Iowa, and confined to the northeastern corner. Until the range of V. meramecensis is better known some caution against overcollecting or other damage should be exercised. It would be particularly unfor- tunate if the type locality (subject to periodic flooding if the proposed Meramec dam were built, according to Van Devender, 1979) were lost. Specimens used for this paper have been deposited in the collections of the Field Museum of Natural History (FMNH). LOCALITIES 1. Drift at base of east-facing slope along Brush Creek, Brush Creek Canyon State Pre- serve, NEV4, NEV4, SEV4, SE'A, sec. 17, T92N, R7W, Wadena 7V2' quadrangle, Fairfield Twp., Fayette Co., Iowa. 2. Drift at base of north-facing bluff above Bear Creek, Bixby State Park, center SEV4, SEV4, SWV4, sec. 23, T91N, R5W, Edgewood 7V2' quadrangle, Lodomillo Twp., Clayton Co., Iowa. 3. Live collection and litter sample from dense upland woods on northwest-facing slope above a tributary to Bear Creek, SV2, SEV4, SE'A, SWV4, sec. 23, T91N, R5W, Edgewood 7V2' quadrangle, Lodomillo Twp., Clayton Co., Iowa. 4. Live collection and litter sample from west- facing forested talus slope above Point Hollow Creek, White Pine Hollow State Preserve, NW'/4. SWV4, NEV4, SE'A, sec. 7, T90N, R2W, New Vienna 7V2' quadrangle, Liberty Twp., Dubuque Co., Iowa. DISCUSSION Morphology: Our specimens range in length from 1.72 mm to 2.11 mm, slightly larger than Van Devender's but with a comparable mean length (x = 1.83). The observed widths (1.05 to 1.20 mm, x= 1.08) show an identical range but somewhat smaller mean (x=1.10 for the Missouri specimens). Thus, Iowa specimens are quite similar to the type lot in dimensions but slightly more slender (mean H/D=1.66 vs. 1.62 for the Missouri holotype). According to Van Devender (1979:71) half of the Crawford Co., Missouri, specimens lack a subcolumellar lamel- la. More than 90 percent of the Iowa material show some sign of a subcolumellar lamella, but this is usually vestigial (Figs. 2a-d). None have the subcolumellar as well-developed as the col- umellar; only one or two lack it completely. In most Iowa V. meramecensis, both palatals are equally recessed from the lip edge; nearly all have a knob-like lower palatal, and the long, slightly curved lower palatal present in 19 per- cent of the Missouri specimens characterizes a smaller percentage (<5 percent) of the Iowa specimens. Although both V. meramecensis and V. gouldi gouldi are somewhat variable, mixed lots can be separated on several features. Van Devender (1979:72) emphasizes the smaller teeth and more open aperture of V. meramecensis; she also notes that the less massive and straighter parietal of V. meramecensis tends to point toward the lower palatal, while that of V. gouldi gouldi points between the two palatals. We have illustrated some examples of both species (com- pare Figs. 2a-d with 2e-h) in which these tenden- cies are less pronounced, but even the two most similar examples are clearly separable on aper- tural characters alone (Figs. 2k and 1). Aside from the teeth, the aperture of V. gouldi gouldi is more elongate and the outer lip more strongly constricted. Some differences in gross shell characters should also be mentioned. V. meramecensis has more evenly expanding, slightly shouldered whorls; associated V. gouldi gouldi tend to have Vol. 95(1) January 29, 1981 THE NAUTILUS 35 ^^^i.^'?**/ 41^^^ FIG. 2. Vertigo nieramecensis VanDevender(cdl deposited in the Field Museum of Natural History). a, Largest mature specimen, 2.11 mm. Dubuque Co., la. b, Vertigo meramecensis Van Devender. 2.05 mm. Clayton Co., la. c, Vertigo meramecensis Van Devender. 1.89 mm. Clayton Co., la. d. Vertigo meramecensis Van Devender. 1.89 mm. Clayton Co., la. e. Vertigo gouldi gouldi (Binney). 2.11 mm. Fayette Co., la. f. Vertigo gouldi gouldi (Binney). 1.9U mm. Fayette Co., la. g. Vertigo gouldi gouldi (Binney). 1.92 mm. Fayette Co., la. h. Vertigo gouldi gouldi (Binney). 1.82 mm. Fayette Co., la. i. Ver- tigo gouldi gouldi (Binney). 2.07 mm. Clayton Co.. la. j. Vertigo meramecensis Van Devender. Dubu- que Co., la. k. Vertigo gouldi gouldi (Binney). Enlargernenl of aperture. Fayette Co., la. 1, Vertigo meramecensis Van Devender. Enlargement of aperture. Clayton Co., la. a-j, approximately 25 x ; k-1, approximately 45 x. 36 THE NAUTILUS January 29. 1981 Vol. 95(1) the ultimate and penultimate whorls about equal in width and more evenly rounded. Iowa speci- mens of both are not distinguishable on color (chestnut) and have equally sharply and regular- ly striate mature shell surfaces (Missouri V. meramecensis are more strongly and irregularly striate, according to Van Devender, op. cit.). Shells with mature apertures have between 3V2 and 5 whorls. Ecology: Both Iowa localities with live V. meramecensis are comparatively steep, pro- tected lower slopes with deep, loamy soil and well developed litter interspersed with talus blocks of Niagaran dolomite. The forest is dominated by hard maples [e.g., Acer saccha- rum) and basswood, with common red oak, hick- or}', and dogwood. High slopes at Locality 4 also have common yew (Taxus canadensis) and white pine (Pirnis strobiis). Both support land snails (see Table 1), with Carychium exiguum most abundant. Both retain some mositiire even in late August. Trees are more common and varied at the Clayton Co. locality; the slope at Locality 4 is less stable, more steep, and closer to the creek floodplain, hence moister. The majority of the species collected (slugs were not retained) are common to both (77 percent): those peculiar to one or the other (Locality 3: Stenotrema fratemum. Discus patulus, Gastrocopta cor- ticaria. Vertigo tridentata. Locality 4: Cochlicopa luhrica, Gastrocopta tappaniana, Striatura milium) tend to support the observed differences in tree cover and moisture mention- ed above. Both localities are good examples of habitat 7 of Thorne (1964:19), defined from the same area. Comparable slopes are situated in the immediate vicinitj- of Localities 1 and 2 also; these have not yet been litter sampled. Land snails associated with V. meramecensis at the type locality are low in diversity (Table 1), ver>' likely because the collection was made after dark on a limestone bluff; a litter sample was evidently not practical. Nevertheless, the general features (wooded limestone bluffs) ap- pear comparable to Iowa occurrences. In sum- mary, V. meramecensis seems to prefer rich, deep, moist, well-wooded slopes associated with extensive calcareous rock exposures. Vertigo meramecensis is as yet unknown as a TABLE 1. Assoclstea of V. i leceaalB Van Devender. LocMlltj A Locsllcy 3- Crswford Co.. Dubuque Co., Clayton Co., Trlodopala albolabcla (S'r) T. fosterl (Baker) Mesodoo thyroldus (Say) H. laletua (Blnney) AtloKona prottmda (Say) Baplotreaa concavxm (Say) StenotccBa barbatua (Clapp) S. f ratemuD (Say) Hendersoala occulca (Say) Angulsplra aleemata (Say) Discus patulus (Deshayes) Cochlicopa lubrlca (Muller) Zooltoldes arboreus (Say) Clyphallna Indentata (Say) Sespylcrea electrlna ((wjuld) Caacrocopta contracta (Say) C. cortlcaria (Say) C. holzlngerl (Sterkl) C. pencodoti (Say) C. tap part laja (Adaas) Columella edeotula (Drapamauld) Hellcodlscus parallelus (Say) H. slDRleyaous (Pllsbry) H»50 mm) C. foliatum preyed largely on two bivalves species, Adula californiensis and Protothaca staminea, consistently choosing the latter even though it required drilling and yielded less energy per capture. C. foliatum apparently select P. staminea because they are less likely to be dislodged by rough waves while feeding. The gastropod Ceratostoma foliatum (Gmelin) is a common inhabitant of rocky shores along the northeast Pacific rim from Alaska to Califor- nia. Despite its large size (>100 mm) and com- moness its ecology is poorly known. Functional morphology (Spight and Lyons 1974, Palmer 1977) and life history patterns (Spight et ai, 1974) have been examined in some detail, but only a few feeding observations have been made. Spight et al. (1974) suggest that C. foliatum may follow a dietary strategy similar to that of Muricanthvs nigritus (Philippi) (Paine 1966). Small M. nigritus are specialists on acorn barnacles while large individuals (>40-50 mm shell length) are generalists on gastropods. This dietary shift during ontogeny presumably oc- curs due to the increased energy demands of larger M. nigritus (Paine 1966). With C. foliatum the hypothesized dietary shift is from specialization on barnacles to generalization on bivalves. Based on the presumed adaptiveness of the labial spine on the outer lip of C. foliatum. Spight and Lyons (1974) suggest that the dietary shift should occur when the spine is func- tionally complete. The purpose of this study is to examine two 'Present address: Department of Zoology, University of Maryland, College Park, Maryland 20742. aspects of feeding in C. foliatum,. First, what are the preferred prey, and what factors affect these preferences? Second, does a dietary shift occur during ontogeny when the labial spine becomes functionally complete? MATERIALS AND METHODS The study site was located along the southeast margin of Boiler Bay, Oregon. The area consists of scattered mudstone benches separated by surge channels. The stone is heavily perforated by boring organisms, principally bivalves in the families Pholadidae (Nettastomella rostrata. Penitella penita and Zirfaea pilsbryi) and Mytilidae (Adula californiensis). Empty pholad burrows are inhabited by a variety of nestling species, including the bivalves, Protothaca staminea (Veneridae) and Hiatella arct.ica (Hiatellidae). Mussels (Mytilus califomianus) and small acorn barnacles (Balanus glandula) are scattered over the study site. The density of potential prey was determined by a random quadrat method. A bench-mark was established in the center of the study site using a 2.5 cm diameter white plastic disc held in place with a 5.1 cm long masonry nail. A double set of ran- dom numbers was used to determine the north- south and east- west coordinates of each sample. Quadrats were 15x15 cm on the siu-face and Vol. 95(1) January 29, 1981 THE NAUTILUS 39 rock was removed to a depth where no further boreholes were evident on the newly exposed rock surface. Snails found feeding during these searches were measured (shell length from ape.x to tip of siphonal canal) and the prey identified and measured. The method of attack was also noted. The laboratory experiments were conducted in a 50 X 50 cm clear Plexiglas tank with con- stantly circulating 3.3% seawater. Water depth was maintained at 4 cm. During the study water temperature varied from 15-17°C. Eight snails, ranging from 31 to 69 mm shell length were placed in the tank and starved for seven days. Eight specimens of each of six prey species (i.e., B. glandula. A. caJifoniiensis. M. californianuji. N. rostrata, P. staminea, and Z. pilsbryi) were then placed in the tank. Individual prey were placed randomly using a grid system and two sets of random numbers for determining coor- dinates. Specimens for each species represented the full size range available in the field. Prey items were replaced with another individual of the same species and size when eaten. The tank was covered during the experiment with black plastic. The experiment was checked at least every 12 hours. As with the field observations C. foliatum length, prey species, prey length and method of attack were recorded. Two prey species. P. penita and//, ardica, were not abun- dant enough to be used in the laboratory studies. Caloric contents of the prey species were determined using a Parr oxygen bomb calori- meter (Anonymous, 1960). Prey were dried to a constant weight at 80°C, the dried tissues were removed from the shell and then tested accord- ing to the protocol in the Parr manual. RESULTS C. foliatum of all sizes use two different methods of attacking prey. Bivalves with an ob- vious siphonal gape (i.e., A. califoryiiensis) were attacked by direct eversion of the proboscis through the gape. The siphonal region of the bivalve shells attacked in this manner showed no evidence of drilling activity, strongly suggesting that the radula and accessory boring organ were not used to enlarge the siphonal gape before proboscis eversion. Snails feeding in this man- ner had the head placed directly over the sipho- nal gape of the prey. The anterio-lateral corners of the propodium were extended anteriorly and medially to form a short tubular channel be- tween the mouth and siphonal gape. The pro- boscis was extended through this channel. The labial spine was frequently observed pressed against the substrate to assure a firm purchase while feeding. A different method of attack is used against prey such as Protothaca staminea which lacks a prominent siphonal gape. These prey were drill- ed through the valves, a mechanism widely used by muricid gastropods (see review by Carriker and Williams 1978). In the study area P. staminea normally occurs in empty Penitella penita burrows which have a small external opening and a spacious interior partially filled with sediment. C. foliatum feeding on these clams fold the lateral margins on the anterior half of the foot dorso-medially to form a tubular channel for the proboscis. This portion of the foot is everted through the burrow opening, and, once into the interior of the burrow it becomes greatly inflated (Fig. 1). Presumably FIG. 1. Ceratostoma foliatum edge-drilling a Pro- tothaca staminea iii an empty pholad burrow. Is, labial spine: rv, right varii: dv, dorsal varix; ef, everted portion of foot tvitk right and left halves folded dorsally to form a tubular channel for the proboscis. 40 THE NAUTILUS January 29, 1981 Vol. 95(1) Ihe swelling is brought about by the transfer of body fluids into the extended portion of the foot. The anterior tip of the foot is attached to the prey, thus bringing the accessory boring organ and the radula (at the tip of the everted pro- boscis) close to the prey's valves. Of the clams attacked in this manner, 82% were drilled at the juncture of the valve edges where the shell is thinnest. The remaining 18% were drilled through one of the valves. The labial spine is not important in anchoring the snail to the sub- strate, since it is rarely pressed against the -substrate as it is when A califomiensis is being attacked. I have found C. foliatum harder to remove from the substrate when it is feeding on P. staminea rather than on A. calif oniiensis simply because of the difficulty of pulling the swollen portion of the foot through the small burrow opening. Spight and Lyons (1974) suggested that the diet of C. foliatum should shift at a shell length of 60 mm since at this size the labial spine be- comes functionally complete. The C. foliatum at Boiler Bay reach a smaller size than those in Spight and Lyon's study. With the exception of a single, high-spired specimen of 82 mm, none of 168 individuals examined during the study ex- ceeded 70 mm. The labial spine of Boiler Bay C. foliatum becomes functional when the shell reaches a length of about 50 mm. Because of this difference, I use 50 mm as the predicted size at which the dietary shift should occur in all the analyses which follow. The results of the field feeding observations for small (<50 mm) and large (>50 mm) C. foliatum for the period of April to August 1976 are compared using the chi-square test. Only those prey items eaten are listed in Table 1. TABLE 1. Field observations of feeding by small (<50 mm) and large (>50 mm) Ceratostoma foliatum. Diets for the two size classes are compared using the chi-square test (3?) and show no significant relationship between size and diet (x' = 2.S3. p>0.05). Other available prey are listed in Table 3. Diet is not related to size (x^ = 2.33, p>0.05). A similar treatment for laboratory feedings also shows no significant relationship between size and diet (x2= 1.39, p>0.05; Table 2). A dietary shift does not occur when the labial spine becomes func- tional in C. foliatum from Boiler Bay. TABLE 2. Lnhorntory feeding observations for small (4:50 mm) and large 050 mm) Ceratostoma foliatum. Diets are compared using the chi-square test and show no significant correlation between size and diet fx'' = l-39. p>0.05). 31 to 50 mm 51 to 69 mm Number % Number % eaten Diet eaten Diet C foliatum size range Prey species C. foliatum size range 12 to 50 mm 51 to 70 mm Number % Number % Prey species eaten Diet eaten Diet Adula califomiensis 8 53 16 47 Hiatella arctiea 1 7 0 0 Protothaca staminea 6 40 18 53 Adula califomiensis 1 13 4 22 Mytilus califomianus 0 0 2 11 Protothaca staminea 7 87 12 67 A number of prey characteristics may affect prey choice, although two, energy content (see review by Pyke et al. 1977) and abundance (Rap- port 1971, Emlen 1973, Estabrook and Dunham 1976), are frequently considered to be the most important. The energy content of each prey species and the abundance of each species in both the field and laboratory observations are listed in Table 3. Only those species in families on which C. foliaium is known to prey are in- cluded in Table 3 (Spight et al. 1974, this paper). Because there was no relationship between size and diet within each set of observations the re- sults were pooled (Table 3). The two most pre- ferred prey (P. staminea and A. califomiensis) are both high in energy content and common. But neither energy content nor abundance alone is an adequate predictor of preferred prey. The energetically most valuable prey (A. califomien- sis) only represented 21% of the laboratory diet, while P. staminea accounted for 71% of the laboratory diet. This preference for P. staminea is even more surprising, since P. staminea must be drilled before it can be eaten. Such drilling is not required for feeding on A. califomiensis. In the field, A. califomiensis and P. staminea each represent 49% of the diet. This change is pre- sumably the result of A. califomiensis being almost twice as common as P. staminea (Table 3). However, A'^. rostrata, which is also nearly twice as common as P. staminea was not eaten Vol. 95(1) January 29, 1981 THE NAUTILUS 41 TABLE 3. Summary of prey charactertistics and percent of diet in laboratory andfield conditions. Since there is no significant difference between the diets of small and large snails in either the laboratory or the field the data haiv been combined urithin each treatment. Lahoratoi '-y Field Mean Energy content Abundance % Abundance % Prey species (Cal. /ash-free g.) (no./m2) Diet (no,/m^) Diet Balanus glandula - 32 0 11 0 Adula californiensis 4713 32 21 293 49 Hintella arctica -- 9 2 Mytilws califomianus 4596 32 8 0 0 Nettastomella rostrata 3918 32 0 276 0 Penitella penita 4161 9 0 Protothaca staminea 4560 32 71 151 49 Zirfaea pihbryi 3714 32 0 98 0 even though C. foliatum has been observed feeding on other Pholadidae (Spight et al. 1974). DISCUSSION The labial spine appears to allow C. foliatum a greater purchase while feeding on certain prey, such as Adula californiensis, and possibly also during quiescent periods. A mature labial spine is clearly not needed to feed on bivalves, since small C. foliatum with poorly developed spines readily do so. Whether very small C. foliatum (about 10 mm or less), which lack a labial spine, can successfully attack bivalves is unknown. Such small snails are difficult to find in the com- plex environment at Boiler Bay. The absence of the hypothesized dietary shift may be partially due to the time of the year of the study. Barnacle densities were particularly low at Boiler Bay while the field study was in progress (Table 3). Under such conditions spe- cialization on barnacles may not be a viable alternative for small C. foliatum. Spight, et al. (1974) have found that C. foliatum responds to yearly fluctuations in barnacle density. When barnacles are abundant they are heavily preyed upon by C. foliatum. During lean years bar- nacles are infrequently eaten. Spight, et al. do not list the prey eaten when barnacles are rare, but the observations reported here suggest that C. foliatum of all sizes prey on bivalves when barnacles are unavailable. Several factors affect prey selection. Energy content and abundance are important, since the two preferred prey (P. staminea and A. califor- niensis) are both common and energy rich, but do not adequately explain why /I. californiensis is not more frequently eaten that it is. This mussel is the most abundant prey, has the high- est energy content, and requires no preparatory drilling before ingestion. Yet A. califomiensis is only eaten as frequently as P. staminea which is both lower in abundance and energy content and requires drilling prior to ingestion. One pos- sible explanation for this paradox is the reduced risk to the snail of being dislodged. Feeding C. foliatum were frequently observed to be in more exposed positions than quiescent snails. Preda- tors (Palmer 1977) or heavy surf (Menge 1978, pers. observ.) can readily remove exposed snails. Palmer (1977) has shown that the foliated varices of large C. foliatum significantly in- creases the probability that the snail will land with the aperture down, protecting the vulner- able foot from predatory fish. Palmer's results were obtained in still water, so it is unclear whether the same results would be obtained in surf. At Boiler Bay dislodged snails are fre- quently found being held upside down on the dorsal surface of the sea urchin Strongylocen- trotus purpuratus. Normally this accounts for less than 1% of the C. foliatum observed, although after a storm as much as 11% of the population may be stranded on urchins (Kent, unpubl.). Stranded C. foliatum. probably perish since they appear to lack any means of escape. Snails feeding in exposed positions would be most susceptible to being dislodged. The in- creased ability to remain attached while feeding 42 THE NAUTILUS January 29, 1981 Vol. 95(1) on P. staminea (due to the inflated foot) would reduce the risk of being dislodged and increase the "value" of P. staminea as a prey item. A. caUfomien,'iis is more abundant and higher in energy content, but feeding on A. califomiensis incurs greater risk of being dislodged by predators or heavy wave action. The relative risks of being dislodged may also explain the concurrent development of the labial spine and the foliated varices in C. foliatwm. In small C. foliatum the labial spine and varices are absent or poorly developed, but become increas- ingly well developed as the snail grows larger (Spight and Lyons 1974). At Boiler Bay small C. foliatum. are most frequently observed in crev- ices and depressions where they would be rela- tively immune to disturbance by either preda- tory fish or surf. Larger C. foliatum have few refugia and are more exposed, particularly when feeding. Large varices would reduce fish predation but would increase the risk of being dislodged by surf (Palmer 1977). The labial spine conteracts this tendency by assuring a firm pur- chase to the substrate. The labial spine of C. foliatum is not used for attacking new types of prey. Rather it functions as a handy tool for assuring a firm purchase while feeding in exposed positions. Where an even firmer purchase can be obtained by anchor- ing the foot in a burrow the labial spine is not used. At Boiler Bay the risk of being dislodged appears to be so high that prey preferences of C. foliatum, have been affected. ACKNOWLEDGMENTS I wish to thank C. J. Bayne and J. C. Ruther- ford for helping during early stages of this work, J. L. Kent for assistance during the field work, and M. L. Reaka, E. M. Bird, and J. A. Veil for helpful discussions. I would like to thank G. J. Vermeij and T. M. Spight for their com- ments on this manuscript. LITERATURE CITED Anonymous 1960. Oxygen bomb calorimetry and combus- tion methods. Technical manual no. 130. Parr Instrument Co., Moline, Illinois. Carriker, M. R. and L. G. Williams. 1978. The chemical mechanism of shell dissolution by predatory boring gas- tropods: a review and an hypothesis. Malacologia 17: 143-156. Emlen, J. M. 1973. Ecology: an evolutionary approach. Addison-Wesley Pub. Co., Reading, Mass., 493 pp. Estabrook, G. F. and A. E. Dunham. 1976. Optimal diet as a function of absolute abundance, relative abundance, and relative value of available prey. Amer. Natur. 110: 401-413. Menge, B. A. 1978. Predation intensity in a rocky intertidal community. Relation between predator foraging activity and environmental harshness. Oecologia 34:1-16. Paine, R. T. 1966. Function of labial spines, composition of diet, and size of certain marine gastropods. Veliger 9: 17-24. Palmer, A. R. 1977. Function of shell sculpture in marine gastropods: hydrodynamic destabilization in Ceratostoma foliatum. Science 197:1293-129.5. Pyke, G. H., H. R. Pulliam and E. L. Charnov. 1977. Opti- mal foraging: a selective review of theories and tests. Quart. Rev. Biol. 52:137-154. Rapport, D. J. 1971. An optimization model of food selection. Amer. Natur. 105:575-587. Spight, T. M., C. Birkeland and A. Lyons. 1974. Life his- tories of large and small murexes (Prosobranchia: Muri- cidae). Marine Biol. 24:229-242. Spight, T. M. and A. Lyons. 1974. Development and func- tions of the shell sculpture of the marine snail Ceratosto- ma foliatum. Marine Biol. 24:77-83. Major Research and Identification Classic for Sale Lovell Reeve's CONCHOLOGIA ICONICA (1843-1878) This is the largest and most famous of the 19th century master works on conchology, containing 1,840 exquisite handpainted litho- graphic plates of many hundreds of new species. This excellent set, bound in contem- porary blue buchram in 23 volumes, contains all the then-known marine mollusks of the world. It lacks the land and freshwater parts dealing with such groups as Helix and Uyiio. The set has unusually fine colored plates of Murex, Voluta, Cypraea. Pecten. Coyius, Tur- ris, Mitra, and other popular groups. In addi- tion, there are 43 plates photostated of rare, unattainable parts. Write: Dr. R. Tucker Ab- bott, P. 0. Box 2255, Melbourne, FL 32901. Vol. 95 (1) January 29, 1981 THE NAUTILUS 43 A METHOD OF COLLECTING MINUTE LAND SNAILS C. Cliff Coney', Wallace A. Tarpley and Robert Bohannan Department of Biological Sciences East Tennessee State University Johnson City, Tennessee 37601 ABSTRACT A method is described which will facilitate the processing of leaf litter for dead shells of the Pupillidae and other molluscan micro-fauna by utilizing floatation of the shells against the different density gradients of water and xylene hydrocar- bons. Most of the undamaged dead shells which were present in the original sam- ple may be recovered by this process. County and state records for the Pupillidae and other minute land snails indicate widely scattered distributions when compared to the reported ranges of the larger and more obvious land snails. This may be due to the difficulty en- countered in processing large amounts of leaf litter for its molluscan micro-faunal content. The method of collection of minute land snails used by previous workers has largely been car- ried out by a process of sifting dried moss and leaf litter debris, followed by a laborious and time-consuming ordeal of hand-picking the residue (La Rocque, 1974; Smith, 1910; Sterki, 1887). Laver (1878) introduced the method of winnowing leaf litter in the wind, and thereby utilizing the force of the wind to carry away the unwanted debris. This method unfortunately in- troduces bias into the sample by the certain loss of such genera as Punctum, Striatura, and Ver- tigo. A more suitable means of separating the majority of the leaf litter debris involves the in- novative addition of water floatation to the original process of dry sifting of leaf litter (Evans, 1972). We have developed a method which will pro- vide a maximum yield of molluscan shells with a minimum expenditure of time and effort. A leaf litter or moss sample is taken so as to include from 5 cm to 10 cm of soil. This will insure ade- quate sampling of the fine leaf/soil interface where many of the minute gastropods thrive. The contents of the sample should be placed on a screen having a 5-mm-square mesh which has been suspended over a deep bucket. The sample can then be gradually washed with water through the screen and into the bottom of the bucket. The fraction of sample which remains on the 5-mm screen should be searched for large land snails. Examination of the contents of the bucket after the initial washing phase will reveal a layer of detritus containing dead mollusk shells floating on the surface as a result of air trapped within their spires; the heavier fraction of soil and rock detritus will have settled to the bottom of the bucket. The floatant should be skimmed off the surface of the water and placed on a No. 60 mesh brass screen and allowed to drain. We have found it desirable to gently wash this fraction with tap water to remove the finest particles of floatant. The remaining fine detritus containing small mollusk shells should then be dried in an oven at about 60 °C until the sample is completely dried. Forty-eight hours is usually sufficient drying time unless the sample con- tains a large amount of rotted wood or bog humus. When thoroughly dry, the sample should be sifted into a beaker containing xylene and allow- ed to settle out for approximately one hour with periodic agitation until the fine debris stops fall- ing to the bottom of the beaker. The remaining suspended floatant can then be skimmed off the surface of the liquid and placed on filter paper and allowed to drain dry at room temperature. When dry, this remaining fraction can be ex- amined under a stereoscopic microscope or hand lens and the mollusk shells removed by touching a probe wetted with ethyl alcohol to the shells 'Present address: Dept. of Biology, Coastal Carolina College, Conway, S.C. 29526. 44 THE NAUTILUS January 29, 1981 Vol. 95(1) which will adhere to the probe. The shells may be collected in a vial of alcohol and subsequently dried at 60°C if desired. A word of caution! Xylene has been determin- ed to be a possible carcinogen; therefore, one should be sure that the work area is well ven- tilated and skin contact avoided as this sub- stance may be absorbed through the skin with prolonged use. Other hydrocarbons such as toluene or benzene may be substituted providing the above precautions are adhered to. Unfortunately, the above described floatation technique cannot be employed on clastic clay samples from Pleistocene cave deposits since the shells from these deposits are typically filled with clay. The following method has been found to yield satisfactory results for examining Pleistocene cave deposits for the molluscan micro-faunal contents. The sample is dried in an oven at 60°C until thoroughly dry, then it is covered with a hydrocarbon such as kerosene or varsol and allowed to stand overnight. After decanting the hydrocarbon, the sample is im- mediately covered with a mixture of boiling water and detergent and allowed to sit for a few hours. This will allow the clay to be broken up in- to finely particulate sediments thus preparing the sample for gentle washing through a 5 mm square mesh screen and into a collection bucket. After the contents of the sample remaining on the screen are examined, the fraction of sample collected in the bottom of the bucket is poured on to a No. 60 mesh brass screen and washed thoroughly with water. The fraction remaining on the No. 60 mesh brass screen is then dried in an oven at 60°C. The dried sample may then be examined under a stereoscopic microscope for molluscan content. ACKNOWLEDGMENTS We would like to thank Dr. Jeff G. Wardeska for suggesting the possibility of hydrocarbon floatation. We are also indebted to Dr. Dan M. Johnson and Mr. Charles H. Coney for critically reading the manuscript. LITERATURE CITED Evans, John G. 1972. Land Snail in Archaeology. Seminar Press, London. xiiH-436 pp., 145 figs. La Rocque, Aurele. 1974. Short notes on land snails. In: How to Study and Collect Shells: A symposium, 4th ed. Ameri- can Malacological Union, pp. 69-71. Laver, Henry. 1878. Suggestions for finding the smaller land shells. The Quarterly Journal of Conchology . 1:264. Smith, Herbert H. 1910. Directions for Collecting Land Shells. Museum of the Geological Survey of Alabama. 12 pp. Sterki, Victor. 1887. Hcnt) to Collect Small Land Shells. The Conchologist's Exchange, l(ll):67-68. Vol. 95(1) January ^9, 1981 THE NAUTILUS 45 GUIDE TO THE NUDIBRANCHS OF CALIFORNIA INCLUDING MOST SPECIES FOUND FROM ALASKA TO OREGON B^ C\R> R, McDonald AND ddited B\ R Juikt-r Des.tine(i to be the "bible lor tidepool dnd scubj biologists, the Guide (o Ihe Mudibrantlr. ol Calilornia will equally serve those researchers from Alaska and Pacific Canada to Oregon The extensive informal ionon the specialized toods and habitats ot each species will aid not only in identification but also in ecological analyses. Unique among similar guides, this book has the advantage ol ex- tensive keys, authoritative information and convenient [ihylogenefic organization. This book will be welcomed by marine hinlogisis amateur naturalists, marine aquarium enthusiasts, and students ol oceanography. Years in the making, this compact account gives the stientific essentials to all the known nudibranchs snails ol Caliform.i, uu ludmg the higher classification and descriptions of eaih genus with iheir type-species. With top quality in photography and undeisl.indable concise morphological descriptions identilKalions ot species are made much easier american malacologists Pi HLISHEKS of DlSnM:TI\'E BiVKS O.V MliLLUSKS P O BOX 2255 MELBOURNE FLORIDA 32901 ),AMtS W. NVBAKKtN Ai)hi)tll 1 1 2 color [jiates 64 [iages ■^^- r- • . i^ Solfcover $1 i,30 ^■\'::--'i •i '. ' L • -^-k X\-\- ^l^^ • BIOLOGY • KEY TO SPECIES • GENERIC DESCRIPTIONS • SPECIES DESCRIPTIONS • 112 COLOR PLATES OF LIVING ANIMALS • CC:)LLECTING TECHNIQUES • PHOTOGRAPHING TECHNIQUES, • ANATOM\ .m'^l • BIBLK^GRAPhn i'^ :^s m^^^'^ M\ sS% Freshwater Snails of Africa and their Medical Importance by David S. Brown DISCOUNT PRICE TO NAUTILUS SUBSCRIBERS $49.00 (plus postage) Regular price $55.00 (plus postage) For the first time: A comprehensive account of freshwater snjiils in Africa and neighbouring islands. An exhaustive guide to species of medical and veterinary importance. An invaluable reference work for malacologists, epidemiologists, parasitologists, freshwater biologists and biogeographers. Published by TAYLOR & FRANCIS LTD, LONDON. Distributed in the Americas by AMERICAN MALACOLOGISTS, INC. FLORIDA. The knowledge resulting from Intensive study in recent years is brought together for the first time in this book. Dr. Brown presents a systematic synopsis of nearly 400 species, most of them illustrated, together with chapters on host/parasite relations, snail control, ecology, distribution and biogeography, accompanied by many maps, photographs of shells and drawings. Dr. David S. Brown is a senior scientist on the staff of the Medical Research Council of Great Britain and has been based for 20 years at the British Museum (Natural History) working with a team on research into host/parasite relations. During long periods of field- work in Africa, he has studied the entire gastropod fauna of fresh and brackish waters over large areas of the continent. 450 pp. 230 X 152nim (9 x 6" 0 85066 145 5 Cloth 153 Figs. 46 THE NAUTILUS January 29, 1981 Vol. 95(1) REVIEW Brown, Davis S. 1980. Freshwater Snails of Africa and their Medical Importance. 487 pp. , 153 pis. Taylor and Francis, Ltd., London. Distributed in the Americas by American Malacologists, Inc., P. 0. Box 2255, Mel- bourne, FL 32901. Hardback, £25 in England, $55.00 U.S. Dr. Brown's book on the "Freshwater Snails of Africa" is a welcome addition to regional faunal works of Africa, such as Pallary, 1909 (Egypt); Pilsbry and Bequaert, 1927 (Zaire, former Belgian Congo); Connolly, 1939 (South Africa); Mandahl-Barth, 1954 (Uganda); Wright, 1963 (Angola), and Brown, 1965 (Ethiopia). The book begins with a systematic synopsis (Chapters 2, 3 and 4) of the Prosobranchia and the Basommatophora of the Euthyneura. The families and genera of African freshwater gastropods can be identified by means of keys (Chapter 2). The systematic synopsis includes distributional maps and information about ecology and parasites. Such essential informa- tion is presented for nearly 400 species, almost all illustrated in photographs or line drawings. Facts relevant to the study of biogeography are particularly difficult to segregate, and are found in many chapters. Investigators on snail biology and distribution have expended a great amount of effort in trying to explain the local distribu- tions of particular snails in terms of physical and chemical limiting factors in the environment; some observations from the field and laboratory are summarized (Chapters 10 and 11). Chapter 12 deals with regional faunas and is an excellent feature of the book. For each zone there is a list of species encountered, with up-to-date nomen- clature. These regions include North and Southern Africa, large lakes and major river basins. In addition to a subject index, there is a very useful taxonomic index. An Appendix in- cludes methods used in studying snails. This book is a must for those interested in the freshwater snails of Africa, their up-to-date systematic status, their geographic distribution, ecology, and their medical and economic impor- tance.-£'rni/.e A. Malik, Tulane University, New Orleans. american malacologists (305) 725-22fi0 PC BOX 2255 MELBOURNE. FLORIDA 32901, U.S.A. PUBLISHERS OF DISTIWriVE BOOKS UN MOLLUSKS Abbott, R. Tucker, editor THE BEST OF THE NAUTILUS. 1976. 288 pp An exciting and nostalgic anthology of stiell collecting In ttie Nlneteentti Century, ISBN 0-91572602X Clotfi $13 95 Arakawa, K Y SHELLS ON STAMPS OF THE WORLD. 1979. 234 pp , 15 color pis , text figs lllus Catalog and classifications ISBN0-915B26-070 Clotfl$1595 Bouchet, P SEASHELLS OF WESTERN EUROPE. 1980 (Jan.) 144 pp , all color, living animals, habitats ISSN 0-915826-05-4 Paperback $ 8,95 Houbrick, RIcriard S THE FAMILY CERITHiDAE IN THE INDOPACIFiC 1979 130 pp , 98 pis . 3 In color Monographs of Marine Moiiusca no 1, with buchramlooseieat binder ISSN 0162-8321 $26 00 Wagner. H J L ■ Abbott. 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Continued by H. Burrington Baker. Editor-in-Chief: R. Tucker Abbott EDITORIAL COMMITTEE CONSULTING EDITORS Dr. William J. Clench Curator Emeritus Museum of Comparative Zoology Cambridge, Mass. 02138 Dr. William K. Emerson Department of Living Invertebrates The American Museum of Natural History New York, New York 10024 Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, Ohio 43210 Dr. James H. McLean Los Angeles County Museum of Natural History 900 Exposition Boulevard Los Angeles, California 90007 Dr. Arthur S. Merrill 103 West 8th Avenue Cudjoe Gardens Summerland Key, Florida 33043 Dr. Donald R. Moore Division of Marine Geology School of Marine and Atmospheric Science 10 Rickenbacker Causeway Miami, Florida 33149 Dr. Joseph Rosewater Division of Mollusks U.S. National Museum Washington, D.C. 20560 Dr. G. Alan Solem Department of Invertebrates Field Museum of Natural History Chicago, Illinois 60605 Dr. David H. 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(United Parcel Address: 2208 South Colonial Drive, Melbourne, FL 32901) Mail: Box 2255, Melbourne, FL 32901 Second Qass Postage paid at Melbourne, Florida and other post offices Subscription Price: $12.00 (.see inside back cover) $14.00 (foreign); institutions $18.00 THE NAUTILUS Volume 95, number 2 - April 30, 1981 ISSN 0028-1344 CONTENTS Terrence J. Frest and R. Sanders Rhodes II Oreohelix strigosa cooperi (Binney) in the Midwest Pleistocene 47 C. M. Way, Daniel J. Hornbach and Albert J. Burky Seasonal Metabolism of the Sphaeriid Clam, Musculium partumeium, from a Permanent and a Temporary Pond 55 Robert S. Prezant Taxonomic Re-evaluation of the Bivalve Family Lyonsiidae 58 James F. Quinn, Jr. A New Genus of Turbinellidae (Gastropoda: Prosobranchia), with the Description of a New Species from the Caribbean Sea 72 William K. Emerson and Anthony D'Attilio Remarks on Muricodrupa Iredale, 1918 (Muricidae: Thaidinae), with the Description of a New Species 77 Bruce Einsohn New Records of Land Mollusca in New York City 82 Arthur H. Clarke Corbicula Jluminea, in Lake Erie 83 Marc J. Imlay, John W. Arthur, Barbara J. Halligan and John H. Steinmetz Life Cycle of the Freshwater Snail Campelama decisum (Viviparidae) in the Laboratory 84 Marian E. Havlik The Northern Extension of the Range of Anodonta suborbiculata Say (Bivalvia: Unionidae) 89 Emile A. Maiek and W. Lobato Paraense Some Peruvian Hydrobiids, Potential Snail Hosts of Paragonimiasis 91 Ralph W. Taylor Freshwater Naiades of Eagle Creek, a Tributary of the Kentucky River (Unionidae) 93 Leroy H. Poorman and David K. Mulliner A New Species of Crosslandia (Nudibranchia: Dendronotacea) from the Gulf of California 96 News 88 Vol. 95(2) April 30, 1981 THE NAUTILUS 47 OREOHELIX STRIGOSA COOPERI (BINNEY) IN THE MIDWEST PLEISTOCENE Terrence J. Frest and R. Sanders Rhodes II Department of Geology The University of Iowa Iowa City, Iowa 52242 ABSTRACT The pulmonate gastropod, Oreohelix strigosa cooperi (Binney), occurs in the lower few feet of the Peoria Loess (Pleistocene: Wisconsinan) in a narrow band of localities from, southwestern Iowa to western Illinois, disjunct by more than 3^0 miles east of the nearest moderyi occurrence. New localities include the western- most and easternmost Pleistocene stations for the subspecies. The Peoria Loess is dated at 22,000 to 12,500 RCYBP, making the bettey-- documented Pleistocene 0. s. cooperi sites Woodfordian in age. Occurrence of Oreohelix and a distinctive associated molluscan faunule implies cooler and drier summers, and perhaps winters, and coniferous forest cover in part of the Peoria Loess outcrop area. The genus Oreohelix is a characteristic ele- ment of the Rocky Mountain molluscan province (Henderson, 1931) and is frequently the only large land snail at many northern and central Rockies localities (Pilsbry, 1939). Its current distribution is centered in Idaho, Nevada, Wyoming, Montana, and Utah, but during Late Pleistocene one species ranged as far east as Il- linois (Fig. 1). This subspecies, originally con- sidered to be typical Patula strigosa Gould (McGee and Call, 1882: Keyes, 1888), was first relegated to the subspecific rank, 0. strigosa cooperi Binney, by Shimek (1890). It was re- garded as a distinct fossil subspecies (iowensis) by Pilsbry (1898 and 1916). He later relegated 0. strigosa iowensis to the synonymy of Oreohelix strigosa cooperi (Binney), and considered these smaller fossils from Iowa and Illinois as similar to modern specimens (Pilsbry, 1939:445). Literature records of varying value are avail- able for several Iowa and Illinois counties. Our collections and museum collections substantiate some old records but others remain to be veri- fied (Table 1). Most old localities cannot be recollected due to the ephemeral nature of many Pleistocene outcrops. In the course of this study new county records for Mills and Linn Counties, Iowa and new local- ities in Polk and Johnson Counties, Iowa and Rock Island County, Illinois were accumulated. Recently collected material, as well as that from completely described old localities, apparently FIG. 1. Map showing approximate recent (gray) and Pleis- tocene (bla£k) distribution o/Oreohelix. Recent distribution based on Pilsbry (1939. fig. 296,312). as modified by Be- quaert and Miller (1973. fig. !f). 48 THE NAUTILUS April 30, 1981 Vol. 95(2) TABLE 1. OccMrrence Data /or Oreohelix strigosa cooperi (Bintiey). Starred localities have been collected by the authors. Ucallty Source Repository ILLINOIS : Carroll Co. Chamberlin t, Salisbury (1888) Cass Co. Uverett (1899) *Roc)c Island Co. Morrison (1943) NHNH, SUI Whiteside Co. HcGee (1891) IOWA: CI ay con Co. Chamberlin & Salisbury (1888) Des Holnes Co. Leverett (1899) •Johnson Co. Shlmek (1888), Cameron (1940) NHNH, ANSP, IMNH SUI. Linn Co. SUI Louisa Co. Udden (1901) •Mills Co. SUI Muscatine Co. Udden (1899) IMNH. NMNH •Polk Co. McCee (. Call (1882) , Keyes (, Call (1892), Bain (1897) NMNH. ANSP, SUI occurs within a few feet of the base of the Peoria Loess. This formation was deposited between 22,000 and 12,500 RCYBP and can exceed 75 feet in thickness (Willman and Frye, 1970). Wood associated with Oreohelix at Locality 5- la dates from 17,170 ±205 RCYBP. At this locality and one other, Oreohelix is associated with abundant spruce macrofossils. This, together with the occurrence of Oreohelix as a member of a distinct faunule within the Peoria Loess, indicates a drier and much cooler climate during the Woodfordian for parts of Iowa and western Illinois. Peoria Loess Oreohe- lix apparently indicate a short-lived incursion of Rocky Mountain elements (and climates) into a limited area of the Midwest during the Wood- fordian. The Midwest fossil localities are the on- ly ones for 0. s. cooperi; the easternmost occur- rence of live specimens is in west central South Dakota, about 350 miles west of the nearest fos- sil occurrence (Mills County, Iowa). All new material has been placed in the Repos- itory, Department of Geology, The University of Iowa (specimens prefixed by the letters SUI). Old collections are at the U. S. National Museum of Natural History (NMNH), Academy of Natur- al Sciences of Philadelphia (ANSP), and The University of Iowa Museum of Natural History (IMNH). LOCALITIES In the course of this study Oreohelix was col- lected from several previously unrecorded sites in Illinois and Iowa, and one Illinois locality was successfully recollected (Morrison, 1943: Rock Island County). Provenance and location are summarized below. 1-1. Mills Co., Iowa. Giangreco local fauna. Alluvial channel fill associated with Peoria Loess, SEV4, NWV4, SW'A, SEV4, sec. 14, T71N, R43W, Mills Co., Iowa. Collected by junior author, 1972. 2-1. Polk Co., Iowa. Saylorville Reservoir sec- tion. Unoxidized Peoria Loess beneath Wiscon- sinan glacial till from Iowa Geological Survey drill hole, NEV4, NEV4, NWV4, sec. 20, T80N, R29W, Des Moines NW 7V2' quadrangle. Oreo- helix and other snails associated with abundant wood and spruce needles. Collected by George Hallberg, 1976. 5-1. Johnson Co., Iowa. Conklin Quarry sec- tion. Peoria Loess above face of River Products Co. Conklin Quarry, Iowa City, NWV4, SE'A, SEV4, sec. 32, T80N, R6W, Iowa City West 7V2' quadrangle. Oreohelix from two sites (a) uncom- monly in unoxidized basal Peoria swale fill on north facing slope above S. wall of quarry, asso- ciated with well preserved wood and spruce needles, seeds, some small mammals as well as other snails; wood date 17,170 ±205 RCYBP; and also in lower several feet of deoxidized loess overlying swale fill; (b) commonly in oxidized Peoria Loess on east facing slope above S. wall of quarry; at this site a barren deoxidized layer of coarse loess separates the fossiliferous unit from the underlying weathered till. Collected by authors and Leslie P. Fay, 1977-1979. 5-2. Johnson Co., Iowa. Iowa City Airport section. Peoria Loess in borrow pit NW of Iowa City Airport, NE corner, NWV4, SWV4, SWV4, sec. 16, T79N, R6W, Iowa City West 7V2' quad- rangle. Collected by Leslie P. Fay and senior author. 1978. 5-3. Johnson Co., Iowa. Pentacrest Apart- ments section. Peoria Loess in excavation for Pentacrest Apartments, Burlington and Capital Vol. 95(2) April 30, 1981 THE NAUTILUS 49 Streets, Iowa City, SWV4, SEV4, SWV4, SWV4, sec. 10, T79N, R6W, Iowa City West 7V2' quad- rangle. Collected by senior author, 1979; no longer exposed. 5-4. Johnson Co., Iowa. Lake MacBride sec- tion. Natural exposure of Peoria Loess along in- termittent stream on N. side of N. arm of Lake MacBride, Lake MacBride State Park, center SV2, SWV4, NWV4, sec. 29, T81N, R6W, Ely 7V2' quadrangle. Collected by authors, 1977 and 1978. 8-1. Rock Island Co., Illinois. Copperas Creek section. Peoria Loess in bank of Copperas Creek, SWV4, NWV4, NWV4, sec. 30, T16N, R6W, Blanchard Island 7V2' quadrangle. Same as Morrison (1943:104). Horberg's (1956:30) Locality 5 may also be the same locality: he gives a detailed section, most of which is no longer exposed, but did not find Oreohelix. Recollected in 1979 by Leslie P. Fay. 8-2. Rock Island Co., Illinois. Moline Airport East section. Peoria Loess exposed in borrow pit for Moline Airport, SWV4, NWV4, SWV4, NWV4, sec. 29, T17N, RIW, Milan 7V2' quad- rangle. Collected by Leslie P. Fay, 1975. 8-3. Rock Island Co., Illinois. Coal Creek sec- tion. Peoria Loess exposed in Peterson Bros. Co. borrow pit along Coal Creek, NEV4, NWV4, NEV4, NWV4, sec. 27, T17N, RIW, Milan 7V2' quadrangle. Collected by Dr. Ann Foster and senior author, 1978 and 1979. Because 0. s. cooperi is generally quite rare, careful collecting is required to secure speci- mens. For example, processing of over 3,500 pounts of matrix from the Mills County site (Locality 1-1) yielded fewer than a dozen Oreohelix. Where possible each locality was visited several times: both hand and bulk collect- ing methods were used. Bulk samples weighed a minimum of one hundred pounds; generally sev- eral times that weight was collected, sieved, and picked for fossils. DISTRIBUTION Reported Pleistocene occurrences of 0. strigosa cooperi are summarized in Table 1 and mapped on Fig. 2. Recent collecting has sub- stantiated the presence of 0. s copperi in Johnson and Polk Counties, Iowa, and in Rock / FIG. 2. Map showing Midwest Pleistocene distribution of Oreoheli.x strigosa cooperi (Binney) by county. Large dots in- dicate areas from which specimens have been examined by the authors; small dots are unsubstantiated literature records. Localities: Iowa-1, Mills Co.; 2, Polk Co.; 3, Clayton Co.; 4, Linn Co.; 5, Johnson Co.; 9, Muscatine Co.; 10, Louisa Co.; 11, Des Moines Co.; Illinois-6, Carrol Co.; 7, Whiteside Co.; 8, Rock Island Co.; 12, Cass Co. Island County, Illinois, and has added Mills County, Iowa to the list. Museum collections are available for Rock Island County, Illinois, and for Johnson, Linn (previously collected but un- published), Muscatine, and Polk Counties, Iowa. We have not been able to substantiate literature records for Carrol, Cass, and Whiteside Coun- ties, Illinois, and for Louisa, Clayton, and Des Moines Counties, Iowa. The unsubstantiated literature records vary in credibility. Carrol, Clayton, and Whiteside County specimens were identified by R. E. Call (Chamberlin and Salisbury, 1888:285, 286; McGee, 1891:448). The Des Moines County col- lection was made by Leverett and identified by C. T. Simpson (Leverett, 1899:169). B. Shimek provided the faunal lists for the Louisa County site (Udden, 1901:113). The Cass County record was based on specimens collected by J. F. Snyder and originally identified as Helix solitaria Say, i.e.. Anguispira kochi (Pfeiffer). Shimek (in Leverett, 1899:173) stated that these specimens probably were 0. s. cooperi since A. kochi has not been found in Woodfordian sedi- ments in Illinois (although present in Altonian and Farmdalian sediments farther south. Leonard and Frye (1960) thought Shimek's sug- gestion might be valid. On the other hand, Baker (1931:290) regarded all Illinois records as doubtful, since his collections from the same counties did not contain Oreohelix. Leonard and Frye (1960) also did not encounter the species in 50 THE NAUTILUS April 30, 1981 Vol. 95(2) central, western, or southern Illinois. However, because 0. >s. cooperi is normally quite rare and hence easily overlooked, and because the chances of misidentification are slim, we ten- tatively accept all of the above records. A report of 0. s. cooperi from Tazwell County, Illinois (Baker, 1922:58) is not plotted on Fig. 2 because it was based on fragments only and Baker later (1931:290) referred these to Triodopsis multi- Lineata wanlessi (Baker). Baker (1920, 1928) records 0. s. cooperi in what he termed Yarmouth, Sangamon, and Peorian deposits. These stratigraphic assign- ments must be reevaluated because considerable refinement of Pleistocene stratigraphy has taken place since Baker's work. Nearly all well- documented Midwest 0. s. cooperi occurrences are from the basal few feet of the Peoria Loess (as defined by Willman and Frye, 1970 in Il- linois) or equivalents, and therefore Woodfor- dian in age. Possible exceptions are the Mills County specimens, which came from an alluvial channel probably associated with the Peoria Loess (and hence very likely Woodfordian), and some Muscatine specimens reported by Udden (1899:328) from a so-called "ante-glacial silt." This unit has not been restudied since Udden's work and as a result is of uncertain age. The Peoria Loess in Illinois spans the Woodfordian substange and dates from 22,000 to 12,500 RCYBP (Willman and Frye, 1970:125); in Iowa the largely equivalent "Wisconsinan" Loess is considered by Ruhe (1969:87) to date from 29,000 to 14,000 RCYBP. As presently known, fossil 0. s. cooperi occurs in a narrow band (average width: 30 mi.) stretching 340 miles from southwestern Iowa to eastern Iowa and western Illinois (Fig. 2). The species appears to be absent from the well- studied Peoria Loess of Nebraska and Kansas (Frankel, 1965; Leonard, 1952), Missouri (Pauken, 1969), Indiana (Johnson, 1965) and the Illinois and lower Mississippi River valleys in Il- linois (Leonard and Frye, 1960). Living Oreohe- lix is endemic to the Rocky Mountain and South- western Molluscan Provinces; it is the dominant genus in the former (Bequaert and Miller, 1973). 0. strigosa in one or another form occupies nearly the whole of the genus range (Fig. 1), i.e., from eastern Washington, southeastern British Columbia and southern Alberta south through Montana, Wyoming, extreme western South Dakota and the west half of Colorado to New Mexico and northern Mexico. To the west it oc- curs in Arizona and southeastern Nevada north through Utah and Idaho. Modern 0. s. cooperi occurs on the northeastern periphery of this range, in the Cypress Hills of Alberta and in the Black Hills of South Dakota (Pilsbry, 1939). This very limited distribution may be an artifact of spotty collecting. On the other hand the extant colonies could represent pre-glacial relicts (Taylor, 1965:606), i.e.. a form widely dis- tributed prior to the Pleistocene whose range was reduced substantially during it. Alterna- tively, 0. s. cooperi may be a recently evolved form adapted to a Pleistocene climate and sur- viving only in areas still retaining similar condi- tions as a glacial relict (e.g., the Midwest endemic Discus macclintocki (Baker), wide- spread in the Midwest Pleistocene but now re- stricted to an extremely limited area in north- eastern Iowa (Hubricht, 1972)). The limited fossil record and present distribution of the genus argue against the last two possibilities. Other species presently limited to the Rocky Mountain Molluscan Province inhabited the Midwest during the Pleistocene, especially the Wisconsinan (e.g., Disctis shimeki. Columella alticola). Moreover, although other Midwest endemics are now known to survive in north- eastern Iowa, no relict populations of Rocky Mountain species have yet been encountered (Frest and Fay, in prep.). At its nearest point the Pleistocene range of the subspecies is dis- junct some 340 miles from its modern range. SHELL MORPHOLOGY Although they are characteristically smaller, fossil specimens of 0. s. cooperi agree very closely with Binney's original description (quoted in Pilsbry, 1939:443) based on recent shells. Measurements of the fifty largest speci- mens from Locality 4 show a considerable range in width and height (W max= 13.8 mm, W min = 10.3 mm, H max = 10.8 mm,_H min = 6.5 mjii; see also FJg^3), but the means (W= 11.7 mm, H = 8.0 mm, H/W = 0.68) are similar to Pilsbry's type of Vol. 95(2) April 30, 1981 THE NAUTILUS 51 0. c. iowmsis (ANSP 10922: W=11.4 mm, H=7.7, H/W = 0.68). Large Recent specimens can exceed 20 mm in diameter. In a series from Lawrence County, South Dakota closely ap- proaching the dirnensions of fossil specimens the five_largest have W = 15.5 mm, H= 11.9 mm, and HAV = 0.77. The umbilical width of both recent and fossil specimens is about one-fifth the shell diameter (Pilsbry, 1939:443-444). Fossil specimens which retain original shell color generally have the two color bands char- acteristic of Oreohelix (Fig. 3b, e, h) but occa- sionally the upper band is faint or absent (Fig. 3q). The base frequently has one or more smaller bands (Fig. 31, r); these also are sometimes faint or absent (Fig. 3f, o). The initial whorls are near- ly smooth (Fig. 3c); later whorls have faint to moderate irregular transverse sculpture and subordinate spiral sculpture (Fig. 3a, d, g, j, m, p). Juveniles are sharply keeled and quite dis- tinct from any other Peoria Loess snails. Mature specimens, fossil or modern, have the aperture strongly deflected and thickened. Fossil speci- mens are not as extreme in this regard as are some modern ones (compare Fig. 3q with Pils- bry, 1939: Fig. 279:34-36). Large fossil specimens have from 5 to 5V2 whorls (Fig. 3p), as do many recent adults. ECOLOGY Relatively little recent ecological data is available for Oreohelix. Hendersen and Daniels (1916) found most species to be calciphiles; the commonest situation is in landslides or talus at the base of limestone cliffs (Henderson and Daniels, 1916; Pilsbry, 1939; Jones, 1940). These same authors note that it mostly occurs in widely scattered, locally dense colonies, a few feet or yards in diameter. We have collected or observed Oreohelix (0. subrudis, 0. pygmaea, 0 yavapai extremitatis, 0. strigosa depressa) in such situations in Wyoming and Alberta. In most cases colonies were clearly delimited by dead shells; commonly a wide scatter of very low density surrounds a much smaller area with nu- merous Oreohelix. Occasionally only a part of the area with common dead shells seemed to be currently occupied by living individuals. With proper rock or debris cover and calcereous soil. forest is not required by most Oreohelix, and the nature of the vegetation is irrelevant (Hender- son and Daniels, 1916:317). 0. strigosa depressa is found "indifferently under either rock or vegetative cover" (Henderson and Daniels, op. cit.) in colonies as described above. This form was collected by Hoff (1962) on the ground, in litter, and under rocks, mostly in mixed aspen, spruce, and fir stands in New Mexico. No speci- i5c information is available for 0. s. cooperi other than that the South Dakota specimens were found in forest on limestone (Pilsbry, 1939:444), but its requirements are probably similar to those of 0. s. depressa. Pleistocene specimens are found in compar- able situations. Though lacking rock cover, vegetated Peoria Loess would provide an ade- quately calcareous habitat for Oreohelix because it is generally quite calcareous where not subse- quently leached; samples analyzed by Frye, Glass, and Willman (1962:49) averaged 9.15 per- cent CO2, and X-ray analyses in Willman and Frye (1970:174-175) showed an average of 16 counts/sec. carbonate minerals in the <2u frac- tion, mostly dolomite. The subspecies is rare at most exposures, with only a few individuals be- ing found {e.g., Shimek (1989) collected a total of 85 specimens from all localities he visited). How- ever, at one Johnson County site (Locality 4) over 365 0. s. cooperi were found. This situation seems analogous to the modern areal distribu- tion; unless exposures were very extensive at a given locality one would expect to find dense col- onies infrequently compared to the less rare oc- currence of scattered individuals. Locality 5-1 exemplifies both situations: the colony at (b) pro- vided most specimens (including all juveniles) while the two scattered occurrences at (a) together yielded fewer than a dozen specimens. Our other localities each had fewer than twelve Oreohelix. Two dozen other land snail species are found with 0. s. cooperi at our localities: the most fre- quent associates are listaed in Table 2. The fauna shows a mix of Holarctic and Nearctic ele- ments, many of which are currently restricted to either the Northern or Rocky Mountain Mol- luscan Provinces in North America; others are 52 THE NAUTILUS April 30, 1981 Vol. 95(2) FIG. 3. Oreohelix strigosa cooperi, Peoria Loess, Johnson County. Iowa: Locality 5-lh. a-b, SUI U9(iG0. diameter=U.6 mm; c, SUI 1,9661. diameter = 3.7 mm; d-f, SUH9662. diameter = 12.1, mm.; g-i, SUI 1,9668. diameter = 12.0 mm; j-1, SUI 1,9661,. diameter =12.3 mm; m-o, SUI 1,9665, diameter = 12.1, mm: p-r, SUI 1,9666. diameter= 13.3 mm. SO widely distributed as to be valueless as snails. There are no southern (Austroriparian) ecological indicators. Only two (Hendersonia oc- elements and only 60 percent of the associated culta, Triodopsis multilineata) are Interior species live currently in Iowa or Illinois; these Vol. 95(2) April 30, 1981 THE NAUTILUS 53 TABLE 2. Common associates o/Oreohelix strigosa cooperi (Binney) in the Peoria Loess. Occurrence In Present Distribution In Taxon lowa-lllinois Distribution Peoria Loess Hendersonla occulta X Nearctlc- Interior widespread Discus cronkheltel X Nearctlc- wldespread widespread Discus shlmekl - Rocky Hts. northern Trlodopsls multllineats X Nearctic- InCerior widespread Cochlicopa lubrica X Holarctlc- widespread widespread Succinea ovalis X Nearctlc- uldespread widespread S. Rrosvenori X Nearctic- widespread widespread Catlnella Relida X Nearctlc- widespread widespread Euconulus fulvus X Holarctic- widespread widespread Vallonia Rracllicosta - Holarctic- Rocky Hts. northern Pupllla muscorun " Holarctlc- Norchem, Rocky Mts. northern Columella altlcola - Nearctic- Rocky Mts. widespread VertlRO oodesta - Holarctic- Northem widespread V. alpestris oughtonl - Holarctic- Northem northern Deroceras laeve X Holarctlc- widespread widespread are mostly widespread and tolerant species. Large snails are low in diversity and absolute numbers. Even if the Interior species are elimi- nated no modern fauna corresponds exactly to that associated with fossil 0. .s. cooperi. How- ever, nearly all of the remainder do occur with modern Oreohelix. The most similar associations are those reported by Beetle (1954, 1957, 1961) from Wyoming, Karlin (1961) from Montana, Colorado, and New Mexico, and Hoff (1962) from New Mexico (with Oreohelix as a consti- tuent) and by Wayne (1959) from northeastern Manitoba (without Oreohelix). Essentially all of the ecologically restricted species (Discus shimeki, Vallonia gracilicosta, Pupilla. mus- corum. Columella altricola, Vertigo alpestris oughtoni, V. modesta) are forms able to survive the cold, somewhat arid conditions of the high Rockies or northern Canada. None is restricted to forest, though most have been found in asso- ciation with trees, especially coniferous forests. Karlin (1961) studied the relation of vegetation types to land snail distribution in Montana, Col- orado, and New Mexico. Of the fifteen associa- tions he discriminated, land snails were most abundant in pure aspen stands, mixed lodgepole pines and aspens, and mixed Englemann spruce- lodgepole pine-aspen forests (1961:61-62). Pure conifer forests commonly had few snails, al- though he assumes that "very small snail popula- tions do exist in most coniferous woods" (1961: 65). Aspens especially would characterize burn- ed or otherwise disturbed areas in largely spruce forests. Disturbance, and establishment of aspen, lodgepole pine, or mixed stands, leads to rapid local population increases for many land snail species (op. cit.). Except under the most favorable conditions of preservation, the nu- merically and areally dominant spruce would be the major plant macrofossil found in a deposit accumulated in an area with the cited plant associations. Karlin (1961:64) also found land snail abundance to be directly correlated with availability of free calcium. At two localities in the Peoria Loess (5- la and 2-1) 0. c. cooperi occurred with abundant con- ifer wood and spruce needles: no plant macro- fossils were preserved at the other localities. It can be inferred that Peoria Loess localities with Oreohelix had a climate with colder, drier sum- mers (and possibly winters as well); the most likely vegetation would be spruce forest (with some aspen as the major deciduous component), possibly reduced to comparatively bare ground in areas nearest the ice margins. Our climatic in- terpretation is analogous to that suggested by Taylor (1965) for parts of the Wisconsinan Great Basin. He believes that the "cool-steppe fauna" of this region in the Early Wisconsinan indicates cooler summers, a lower mean annual tempera- ture, and precipitation no greater (and possibly less) than at present (Taylor, 1965:603-604). However, this description applies to only a small part of the total Peoria Loess (Late Wiscon- sinan) outcrop area; more southerly locales with different land snail assemblages undoubtedly had a somewhat different climate and flora. Lo- calities with Oreohelix, as noted above, have a distinctive fauna atypical of the Peoria Loess as a whole (see, e.g.. the lists of Leonard and Frye, 1960). It is very likely that much of the contro- 54 THE NAUTILUS AprU 30, 1981 Vol. 95(2) versy surrounding interpretation of Peoria Loess ecology (Shimek, 1930, 1931; Baker, 1928; Leonard and Frye, 1960; Taylor, 1965) results in part from failure to discriminate molluscan associations in fine enough detail (Frest and Fay, in prep.). In any case, there is strong evidence that the most severe Pleisto- cene climatic changes in the Midwest occurred during the Wisconsinan (Taylor, 1965). ACKNOWLEDGMENTS Numerous individuals aided this project at one time or another. We are especially indebted to Leslie P. Fay (The University of Iowa) for infor- mation and samples from some Illinois localities. Professor Lon D. Drake and the Department of Geology (The University of Iowa) arranged for the radiocarbon date of wood from Locality 5- la. The University of Iowa Alumni Geology Fund partially funded this publication. Dr. Ann Foster (The University of Iowa) provided speci- mens from the Coal Creek section (Locality 8-3). George Hallberg (Iowa Geological Survey) supplied material from and information on a Survey core from Locality 2-1, as well as a preliminary lithologic description of Locality 5-1. Herbert M. Spitz (Dresser Industries) col- lected some of the Wyoming comparative ma- terial. Margaret Frest typed the first draft; the final version was typed by Gwen Fay. LITERATURE CITED Bain, H. F. 1897. Geology of Polk County. Iowa Geol. Survey Ann. Kept. 9:263-412. Baker, Frank C. 1920. The Life of the Pleistocene, or Glacial Period. Univ. Illinois Bull. 17, 476 p. 1922. Pleistocene Mollusca from Northwestern and Central Illinois. Jour, of Geology 30:43-62. 1928. Molluscan life of the loess deposits of Il- linois. Illinois Acad. Sci. Transactions 20:269-292. 1931. Pulmonate mollusca peculiar to the Pleis- tocene Period particularly the loess deposits. Jour, of Paleontology 5:270-292. Beetle, Dorothy E. 1954. Terrestrial and aquatic Mollusca of Albany County, Wyoming. The Nautilus 67:121-129. . 1957. The Mollusca of Teton County, Wyoming. The Nautilus 71:12-22. 1961. Mollusca of the Big Horn Mountains. The Nautilus 74:95-102. Bequaert, Joseph C. and Walter B. Miller 1973. The Mol- lusca of the arid Southwest. Univ. Arizona Press, Phoenix. 271 p. Cameron, Cornelia C. 1940. The fossils of the Peoria loess of Iowa. Unpublished Ph.D. thesis, Univ. of Iowa. 79 p. Chamberlin, T. C. and R. D. Salisbury 1888. Preliminary paper on the Driftless Area of the Upper Mississippi Valley. U. S. Geol. Survey Ann. Rept. 6:199-322. Frankel, Larry C. 1965. Pleistocene geology and paleoeco- logy of parts of Nebraska and adjacent areas. Unpublished Ph.D. dissertation, Univ. of Nebraska, 297 p. Frye, John C, H. D. Glass, and H. B. Willman 1962. Strati- graphy and mineralogy of the Wisconsinan loesses of Il- linois. Illinois Geol. Survey Circ. 334, 55 p. Henderson, Junius 1931. Molluscan provinces in the western United States. Univ. Colorado Studies 18:173-186. Henderson, Junius and L. E. Daniels 1916. Hunting Mollus- ca in Utah and Idaho. Acad. Nat. Sci. Philadelphia Proc. 69:315-339. Hoff, C. Clayton 1962. Some terrestrial gastropoda from New Mexico. Southwestern Nat. 7: 51-63. Horberg, Leland 1956. Pleistocene deposits along the Mis- sissippi Valley in central-western Illinois. Illinois Geol. Survey Rept. Inv. 192, 39 p. Hubricht, Leslie. 1972. Endangered land snails of the east- ern United States. Sterkiana 45:33. Johnson, Gerald H. 1965. The stratigraphy, paleontology, and paleoecology of the Peoria Loess (Upper Pleistocene) of southwestern Indiana. Unpublished Ph.D. thesis, In- diana Univ., 229 p. Jones, David T. 1940. A study of the Great Basin land snail Oreohelix strigosa depressa (Cockerell). Univ. Utah Bull. 31:1-43. Karlin, Edward J. 1961. Ecological relationships between vegetation and the distribution of land snails in Montana, Colorado, and New Mexico. Amer. Midland Nat. 65: 60-66. Keyes, Charles R. 1888. An annotated catalogue of the Mol- lusca of Iowa. Bull. Essex Inst. 20:61-83. 1890. Notes on the distribution of certain loess fossils, ^rm-r. Geol. 4:119-121. Keyes, Charles R. and R. E. Call 1892. On a Quaternary sec- tion eight miles southeast of Des Moines, Iowa. Iowa Acad. Sci. Proc. 1, pt. 2:30. Leonard, A. Byron 1952. Illinoian and Wisconsinan mollus- can faunas in Kansas. Univ. Kansas Paleontol. Cont. 9 (Mollusca, Art. 4), 38 p. Leonard, A. Byron and John C. Frye 1960. Wisconsinan mol- luscan faunas of the Illinois Valley region. Illinois (}eol. Survey Circ. 304, 32 p. Leverett, Frank C. 1899. The Illinois glacial lobe. U. S. Geol. Survey Monogr. 38, 817 p. McGee, William J. 1891. The Pleistocene history of north- eastern Iowa. U. S. Geol. Survey Ann. Rept. 11:189-757. McGee, William J, and R. E. Call 1882. On the Loss and asso- ciated deposits of Des Moines. Amer. Jour, of Sci. 124: 202-223. Morrison, J. P. E. 1943. Oreohelix east of the Mississippi. The Nautiliui 56:l0i. Pauken, Robert J. 1969. A population study of the Pleisto- cene molluscan faunas in loess of the Missouri River Basin Vol. 95(2) April 30, 1981 THE NAUTILUS 55 in Missouri. Unpublished Ph.D. dissertation, Univ. of Mis- souri-Columbia, 192 p. Pilsbry, Henry A. 1916. Notes on the anatomy of Oreohelix. with a catalogue of the species. Acad. Nat. Sci. Phil- adelphia Proc. 68:340-.59. 1939. Land Mollusca of North America (North of Mexico), V. 1 pt. 1. Acad. Nat. Sci. Philadelphia Mono- graphs 3:1-573. Ruhe, Robert V. 1969. Quaternary landscapes in Iowa. Iowa State Univ. Press, Ames, 255 p. Shimek, Bohumil 1888. Notes on the fossils of the loess at Iowa City, lovis.. Amer. Geol. 1:149-152. 1890. The Mollusca of eastern Iowa. Univ. of louiaStud. Nat. Hist. 1:56-81. 1898. Is the loess of aqueous origin? Iowa Acad. ditions. Ecology 11:673-686. 1931. Ecological conditions during loess deposi- Sci. Proc. 5:32-45. 1930. Land snails as indicators of ecological con- tion. Univ. Iowa Stud. Nat. Hist. 14:38-54. Taylor, Dwight W. 1965. The study of Pleistocene non- marine mollusks in North America, m Wright. H. E., .Jr. and David G. Frey (eds.). The Quaternary of the United States. Princeton University Press: Princeton, New Jersey, 922 p. Udden, J. A. 1899. Geology of Muscatine County. Iowa Geol. Survey Ann. Kept. 9:249-388. 1901. Geology of Louisa County. Iowa Geol. Sur- vey Ann. Kept. 11:57-126. Wayne. William J. 1959. Inland mollusks from Hudson Bay, Manitoba. The Nautilus 72:90-95. Willman, H. B. and John C. Frye 1970. Pleistocene strati- graphy of Illinois. Illinois Geol. Survey Bull. 94, 204 pp. SEASONAL METABOLISM OF THE SPHAERIID CLAM, MUSCULIUM PARTUMEIUM, FROM A PERMANENT AND A TEMPORARY POND C. M. Way, Daniel J. Hornbach' and Albert J. Burky Department of Biology University of Dayton Dayton, Ohio 45469, USA ABSTRACT Seasonal metabolic rates were exayninedfor the sphaeriid clam. Musculium par- tumeium (Say) from a permanent and a temporary pond. For the fall-bom. generation from, the permanent pond and for the single generation from the tem- porary pond, metabolic rates peak during periods of greatest growth and reproduction. Metabolic rates were consistently higher for the permanent pond population. These rates for Musculium partumeium extend the available informa- tion on the family Sphaeriidae to the genus Musculium. One important aspect of the ecology of an organism is its seasonal pattern of metabolism. The majority of the investigations on the metabolic rates of freshwater molluscs have dealt with gastropods (Berg et al., 1962; Berg and Jonasson, 1965; Burky, 1971; Burky, Pacheco, and Pereyra, 1972; McMahon, 1973; Calow, 1976). Metabolic studies of sphaeriid 'Present Address; Department of Biology. University of Virginia, Charlottesville, Virginia 22901. clams have been limited. However, there are reported rates on Pisidiuyn (Johnson and Brinkhurst, 1971b; Jonasson, 1972; Holopainen and Ranta, 1977a, b; Alimov, 1975; Burky and Burky, 1976) and Sphaerium (Alimov, 1975; Waite and Neufeld, 1977; Collins, 1967). The study of Pisidium walkerii by Burky and Burky (1976) is the only seasonal metabolic study in the literature. This study assessed the seasonal metabolic rates of the sphaeriid clam, Muscu- lium partumeium (Say) from a permanent and a temporary pond. 56 THE NAUTILUS April 30, 1981 Vol. 95(2) MATERIALS AND METHODS Clams were collected from a temporary and a permanent pond in SW Ohio (see Way et al., 1980, for a description of the two ponds). The clams were sorted into 6-8 visual size categories (2-30 clams per chamber, depending on size) and oxygen consumption was measured month- ly at field temperature with Clark-type O2 elec- trodes (YSI Model 53 moniter, YSI Model 5331 bath stirrer and chambers) using the acrylic chamber modification described by Burky (1977). After each experiment shell lengths (SL = greatest anterior-posterior dimension) were measured. Clams were dried to constant weight at 90° C, and they were subsequently analyzed for total nitrogen using a Coleman Model 29 nitrogen analyzer. Total dry weights were converted to tissue weights using shell cor- rection values from Burky et al. (1979). Oxygen consumption values are expressed as Qo2 = m1 02/mg dry tissue/hr and Qo2 = m1 02/Mg tissue N/hr. Tissue nitrogen can be assumed to repre- sent protein and helps express the respiration rates in terms of more realistic energy equiva- lents. RESULTS AND DISCUSSION In order to consider seasonal metabolic rates it is necessary to briefly outline the life histories of the two populations (from Way et al., 1980). The ephemeral, or temporary, pond (DW) usual- ly has a single generation per year. Clams are born (mean SL at birth = 1.4 mm) in the spring and early summer (May-July), remain dormant as juveniles in the dry substrate (August- January), begin growth in March (reaching adult SL of 5.9 to 10.1 mm in July), reproduce, and then die as the pond dries during the summer. The permanent pond (AM) has two generations per year. The first generation is born (mean SL at birth = 1.4 mm) in the spring between May and July (AM-SG). These individuals initiate growth during late August (reaching adult SL of 4.4 to 8.0 mm in November), and reproduce be- tween September and November. Some adults of the spring generation overwinter and con- tribute to the next spring generation. Young of the fall, permanent pond, generation (AM-FG) overwinter as subadults (mean SL = 2.4 mm) and experience rapid growth and reproduction in late spring (reaching adult SL of 3.8 to 7.5 mm in July). Most clams of the fall generation die by the end of July, but a few survive to contribute to the new fall generation. For M. partumeium there is no inverse rela- tionship between metabolic rate and size within size series of adults or juveniles. Thus in the metabolic rate equation, M = ^l 02/clam/hr = kW", b=l. In this study b was not significantly different from 1 for any date. Values of b not significantly different from one have been re- ported for gastropods (Daniels and Armitage, 1969; McMahon, 1973; and others), and for the sphaeriid clam Pisidiutn walkerii (Burky and Burky, 1976). It is also indicated in the data of Collins (1967) for Sphcierium occidentale and Johnson and Brinkhurst (1971b) on several genera of Pisidium. One possible explanation for the absence of a size-rate relationship is the small size range of clams within a particular generation. This idea is supported by the fact that for a number of dates where the size range of clams utilized was very small, the regression of log M on log tissue weight was not significant (prob. F<0.05). Burky and Burky (1976) discuss the possible effects of brooding young on b-value (sphaeriids are ovoviviparous) and the signifi- cance of a b-value of one on energy partitioning in P. walkerii. Consequently, oxygen expressed as nl 02/mg dry tissue/hr or y.\ 02/Mg N/hr were averaged for all individuals, regardless of size, within a generation, i.e. all adult values were averaged on a given date as were values for juveniles. Oxygen consumption for adults of the ephem- eral pond (DW) population at field temperature (FT) ranges from 0.58 ^il02/mg tissue/hr, stan- dard error (SE) = 0.04 (or 12.31 i^Wi^g N/hr; SE = 0.46) for clams of mean SL = 7.57 mm in July (FT = 20°C) to 3.23 ^lOa/mg tissue/hr, SE = 0.17 (or 22.65 tilOzl^g N/hr; SE = 1.20) for clams of mean SL = 6.54 in May (FT= 14°C). Oxygen con- sumption averaged 2.29 fil02/mg tissue/hr (or 12.81 Ml02/Mg N/hr) for newborns (May- July) at field temperatures of 14-20°C. Values for adults of the permanent pond, spring generation, (AM-SG) range from 0.49 Ml02/mg tissue/hr, SE = 0.08 (or 4.39 Ml02/Mg Vol. 95(2) April 30, 1981 THE NAUTILUS 57 N/hr, SE = 0.78) to 1.55 ^iWmg tissue/hr (or 14.14 Ml02/Mg N/hr) for clams of mean SL = 6.34 in November (FT = 7.0°C) and for clams of mean SL = 5.97 in May (FT= 15°C) respectively. New- borns of AM-SG (mean SL= 1.4 mm) collected in August (FT = 20-25 °C) average 2.18 Ml02/mg tissue/hr (or 15.56 ^102/^5 N/hr). Permanent pond, fall generation (AM-FG) juveniles (mean SL = 3.16 mm) have metabolic rates averaging 1.64 Ml02/mg tissue/hr (or 14.29 nlOJi^g N/hr) during November-May (FT = 7-15°C), while adults have rates ranging from 1.91 ^102/mg tissue/hr, SE = 0.75 (or 19.79 Ml02/Mg N/hr, SE = 7.67) for clams of mean SL = 5.43 mm in July (FT = 20°C) to 3.36 Ml02/mg tissue/hr, SE = 0.74 (or 35.35 ^^\02l^^g N/hr, SE = 8.34) for clams (mean SL = 5.35 mm) in June (FT= 18.5°C). The comparable values reported in the litera- ture are for the genus Pisidium,: 0.35 to 0.87 ;jl02/mg tissue/hr at field temperatures for P. walkerii (Burky and Burky, 1976); 0.09, 0.15, and 0.33 Ml02/mg tissue/hr at 11°C, 16°C, and 8°C for P. casertanum (Berg et al., 1962; Berg and Jonasson, 1965); and 0.43, 1.08, 1.15, and 1.30 Ml02/mg tissue/hr at 20 °C for P. caser- tanum, P. ventricosum, P. henslowanum, and P. casertanum, respectively (calculated using a 0.5 mg standard clam for Johnson and Brinkhurst, 1971b). Values for other sphaeriids have been reported by Collins (1967), Alimov (1975), and Waite and Neufeld (1977), but oxygen consump- tion is expressed per tissue wet weight or total wet weight (including shell) and thus are not comparable. Oxygen consumption for the fall generation at the permanent pond (AM) rapidly increases dur- ing the months of April and May (2.33 to 4.15 MlOg/mg tissue/hr), corresponding to the period of peak growth and reproduction, with a subse- quent decline over the summer months (4.15 ^lOa/mg tissue/hr in May to 1.91 Hl02nig tissue/hr in late July). Patterns of growth and reproduc- tion for overwintering clams at the ephermal pond (DW) are similar to those of the perma- nent, fall generation (AM-FG) (Way et al., 1980; Hornbach et al., 1980). Therefore it is not sur- prising that the annual patterns of respiration of overwintering ephemeral pond (DW) clams are very similar when compared to the permanent pond ones (AM-FG). Rates increase from April to May (1.42 to 3.23 ^dOj/mg tissue/hr) and then decrease from May to July (3.23 to 0.58 ^ilOg/mg tissue/hr) when the pond dries. The annual respiratory pattern is the same for ephemeral (DW) and permanent (AM-FG) pond generations when the values are based on tissue nitrogen, but oxygen consumption rates are consistently higher for the latter. Clams of the permanent pond (AM-FG) partition more of the total assimi- lated energy to respiration than do those of the ephemeral pond (DW) (56% vs. 38% for AM-FG and DW, respectively; Burky, Hornbach and Way, unpublished data), thus ephemeral pond (DW) clams can direct a greater fraction of the total assimilated energy to growth and repro- duction. ACKNOWLEDGMENTS We would like to thank Mr. J. Koestner, Director of the Dayton Museum of Natural His- tory for permission to collect clams from the pond at Drew Woods (owned by the Eliza Miller Tree Farm, Pike Timberlands, Inc.); Mr. Paul Knoop and Mr. Jack Wood of the Aullwood Audubon Center for permission to collect clams from the marsh pond; and Dr. G. L. Mackie for having confirmed our identification of these clams as Musculium partumeium (Say). Spec- imens are on deposit with the Museum of Zoology, University of Michigan, Ann Arbor, Michigan for the ephemeral pond clams (DW) (Voucher No. 250040) and permanent pond pop- ulations (AM) (Voucher No. 250037). This study has been supported in part by grants to Dr. Albert J. Burky from The Ohio Biological Survey and the University of Dayton Research Council. LITERATURE CITED Alimov. A. F. 1975. The rate of metabolism in freshwater bivalve mollusks. Smi. J. Ecol. (Engl, Transl. Ekologiya) 6:6-13. Berg, K. anri P. M. Jonasson. 196.5. Oxygen consumption of profundal lake animals at low oxygen content of the water. Hydrobiologia 26:131-143. Berg, K., P. M. Jonasson and K. W. Ockelmann. 1962. The respiration of some animals from the profundal zone of a lake. Hydrobiologia 9:1-39. Burky, A. J. 1971. Biomass turnover, respiration and inter- population variation in the stream limpet, Femssia rivu.- laris (Say). Ecol Monogr. 41:235-251. 58 THE NAUTILUS April 30, 1981 Vol. 95(2) ^_^____ 1977. Respiratory chambers for measuring oxy- gen consumption of small aquatic molluscs with Clarke- type polarographic electnxles. Malaeol. Kev. 10:71-72. Burky, A. J. and K. A. Burky. 1976. Seasonal respiratory variation and acclimation in the clam, Pisidium walkerii Sterki. Comp. Biochem. Physwl. 55A: 109-114. Burky, A. J., J. Pacheco and E. Pereyra. 1972. Tempera- ture, water and respiratory regimes of an amphibious snail, Pomacea urcciis (Muller). from the Venezuelan savannah. Biol. Bull 143:304-316. Burky, A. J., M. A. Benjamin, D. M. Catalano and D. J. Hornbach. 1979. The ratio of calcareous and organic shell components of freshwater sphaeriid clams in relation to water hardness and trophic conditions. J. Moll. Stud. 45:312-321. Calow, P. 1976. The respiratory strategies of two species of freshwater gastropods (Ancylus fluviatilis Moll, and Planorbis contortus Linn.) in relation to temperature, oxygen concentration, body size and season. Physiol. Zool. 48:114-129. Collins, T. W. 1967. Oxygen uptake, shell morphology and dessication of the fingernail clam, Sphaerium occidentale Prime. Ph.D. Dissertation. Univ. of Minnesota. (Diss. Abstr. 288:5238, Order No. 68-07294). Holopainen, I. J. and E. Ranta. 1977a. Respiration of Pisi- dium amnmim (Bivalvia) measured by infrared gas analy- sis. Olfcos 28:196-200. 1977b. Carbon dioxide output in the respiration of three Pisidiuvi species (Bivalvia: Sphaeriidae). Oecologia 30:1-8. Hornbach, D. J., C. M. Way and A. J. Burky. 1980. Repro- ductive strategies in the freshwater sphaeriid clam, Mus- culium partumeium (Say), from a permanent and a tem- porary pond. Oecologia 44:164-170. Johnson, M. G. and R. 0. Brinkhurst. 1971b. Production of benthic macroinvertebrates of Bay of Quinte and Lake On- tario. J. Fish. Res. Bd. Canada 28:1699-1714. Jonasson, P. M. 1972. Ecology and production of the pro- fundal benthos in relation to phytoplankton in Lake Esrom. Oikos Suppl. 14:1-148. McMahon, R. F. 1973. Respiratory variation and acclimation in the freshwater limpet, Laevapex fuscus. Biol. Bull. 145:492-508. Waite, J. and G. Neufeld. 1977. Oxygen consumption by Sphaerium simile. Comp. Biochein. Physiol. 57A:373-375. Way, C. M., D. J. Hornbach and A. J. Burky. 1980. Compar- ative life history tactics of the sphaeriid clam, Muscu- lium partumeium. (Say), from a permanent and a tempo- rary pond. Amer. Midi. Nat. 104:319-327. TAXONOMIC RE-EVALUATION OF THE BIVALVE FAMILY LYONSIIDAEi Robert S. Prezant College of Marine Studies University of Delaware Lewes, Delaware 19958 ABSTRACT The taxonomy of the marine lyonsiid bivalves is reviewed and redefinitions of the family and genera are offered. These lyonsiids are divisible into three distinct genera, Lyonsia, Entodesma, and Mytilimera, based primarily upon periostracum and calcareous shell structure, umbonal length ratios, modifica- tions of the mantle edge including the presence of arenophilic radial mantle glands, morphology of the pedal gape, comparative sizes of adductor muscles, mor- phology and size of the foot and byssal systems, modifications of the siphons and general habitats. Some changes in generic taxonomy are suggested. It is also recommended that the present subgeneric taxafor the marine Lyonsiidae be aban- doned since these lower ranks indicate ecomorphs and not tru£ taxonomic units. Few modern workers have concerned them- selves with the systematics of the bivalve sub- class Anomalodesmata. Existing reports are 'College of Marine Studies, University of Delaware Contri- bution No. 151. conflicting and have thrown the taxonomy of this heterogeneous group into a state of confu- sion and disarray. The subclass contains such diverse members as the elongated and cylin- drical clavagellid watering-pot shells, the Vol. 95(2) April 30, 1981 THE NAUTILUS 59 laterally compressed pandorids and the "car- nivorous" septibranchs. The Lyonsiidae are also members of this poor- ly understood subclass. This family, comprising some 20 (Boss, 1971) to 45 species, exhibits characteristics which easily distinguish the group. The subfamilial taxonomy is less precise. Several different versions of lyonsiid taxonomy place from one to twelve extant genera in the family. Some recent authors (Abbott, 1974; Narchi. 1968; Prezant, 1979a) place three gen- era in the Lyonsiidae: Lyonsia, Eyitodesma, and Mytilimeria. Habe (1977) puts four genera in the lyonsiids of Japan (Lyonsia, Allogramu, Bentholyonsia and Agriodesma). and Keen (1969), five genera in the family (Lyoiisia, Allograma, Entodesma. Mytilimeria and Ostomya). Habe first introduced Bentholyonsia as a subgenus (1952), then (1977) elevated it to generic status. The characteristics distinguish- ing this genus from Lyonsia are obscure. Mor- rison (1943) described a new genus and species of lyonsiid, Guianadesma sinuosum, from freshwater rivers of Guyana. This species, ac- cording to Morrison, is the only lyonsiid known to lack an internal calcareous ossicle, the lithodesma, which divides the resilium into two portions. G. siniwsum has many other lyonsiid characteristics in soft parts and shell (overall shell shape, edentulous hinge, fused mantle lobes), but the exact classification must remain tentative until the internal morphology and shell microstructure have been more critically ex- amined. Yonge (1952) felt that Lyonsiidae should include Agriodesma and the three genera advocated by Abbott (1974). Thiele (1935) classified Agriodesma and Entodesma as subgenera of Lyonsia while Dall (1903) placed Entodesma and Lyonsia s.s. as subgenera of Lyonsia, and Allograma and Philippina as sec- tions of Entodesma. According to Lamy (1928), the only valid genus in the family is Lyonsia, with Entodesma, Agriodesma, and Allograma being subgenera. Yokes (1980) has listed ten re- cent, genera in the family: Agriodesma, Allograma, Anticorbula, Bentholyonsia, En- todesma, Guianadesma, Lyonsia, Mytilimeria, Philippina, and Phlycticoncha. Increased data on soft part morphology, be- havior, and paleontology accumulated since the earlier studies have left us with more data on which to draw for taxonomic interpretations. Many early bivalve taxonomic systems were based on a single or very few characteristics, such as fusion of mantle lobes (Dumeril, 1806; Fleming, 1822; Latreille, 1825), shell symmetry and pallial sinus (Linnaeus, 1758; Orbigny, 1843), pedal system (Gray, 1847; Lankester, 1883), adductor muscles ("Philippi, 1853), gills (Fischer, 1886; Pelseneer, 1889; Ridewood, 1903), hinge system (Neumayr, 1884; Dall, 1895), and type of stomach (Purchon, 1959). Dall (1895, 1913) and Douville (1896, 1912, 1913), and later Cox (1960) and Newell (1965), pro- moted total organism taxonomy with corre- lating evidence, as available, from paleontology. For many taxa, sufficient data are now available to permit us to follow this holistic approach in classifying mollusks based on distinct char- acteristics of the entire animal. Recent work on the mantle edge and shell of the Lyonsiidae (Prezant, 1980; 1981) required a corresponding examination of the morphology and behavior of numerous members of this fami- ly and has prompted this re-evaluation of the group's higher taxonomy. Institutional Abbre^nations A/VSP- Academy of Natural Sciences of Phila- delphia, Philadelphia, Pennsylvania CAS - California Academy of Sciences, San Francisco, California LAMN -hos Angeles County Museum of Nat- ural History, Los Angeles, California AfCZ- Museum of Comparative Zoology, Har- vard University, Cambridge, Massachusetts AM/V//- National Museum of Natural History, Smithsonian Institution, Washington, D.C. METHODS AND MATERIALS Lyonsia fioridana, L. hyalina, L. califomica, Entodesma saxicola and Mytilimeria nuttalli were collected live and observed in the labor- atory on a running seawater table at 12°-18°C at 30 ppt salinity. Individuals of the genus Lyon- sia were placed on a sterile, fine sand substra- tum. L. fioridana were originally collected from 60 THE NAUTILUS April 30, 1981 Vol. 95(2) Blind Pass, Sanibel Island, Florida, in shallow waters in a fine-to medium-grained sand and shell substratum. L. hyalina were collected from depths of 14-20 meters in Nahant Bay, Massachusetts, and Delaware Bay, Delaware, in fine sands. Living specimens of L. californica and M. nuttalli were collected from along the coastline of Venice, California. Specimens of live E. saxicola were collected just subtidally on Shaw Island, Washington. Museum specimens included: Lyonsia gouldii (MCZ), L. californica (LAMN), L. pugetensis (NMNH), Entodesma beana (NMNH), E. cuneata (ANSP), E. patagonica (ANSP, NMNH), E. saxicola (CAS), E. truncatissima (ANSP), and Mytilimeria nuttalli (CAS). Spec- imens of E. fretalis and E. chilensis, both found among the colonial tunicate Pyura chilensis, were obtained from Corral Bay, Chile. These were fixed in Zenker's fluid or 10% formalin prior to observations. Measurements were taken to the nearest 0.5 mm with a pair of Mitutoya calipers. Umbonal length ratio measurements are defined as the ratio of the longitudinal distance from the umbo to the anteriormost part of the shell to the horizontal distance from the umbo to the pos- teriormost part of the shell. Histological and electron microscopical techniques are described in detail elsewhere (Prezant, 1979a, b, 1980). In brief, specimens were fixed in Zenker's fluid or 10% formalin, embedded in polyester wax, sec- tioned at 5-10 ^im and stained with Heidenhain's or Groat's hematoxylin and eosin or a modifica- tion of the Pantin trichrome (Prezant, 1979a). For scanning elctron microscopy, shells were dried in ethanol or critically point dried, coated with a thin layer of carbon and gold and examin- ed at accelerating voltages to 15-30 k V in a Philips PSEM 501. RESULTS The family Lyonsiidae is composed of three valid marine genera: Lyonsia, Entodesma, and Mytilimeria. Species within the genus Lyonsia are usually found vertically oriented and partial- ly buried in fine sands or muds with their posterior fifth to third exposed above the substratum. This intertidal to deeply benthic genus has an active foot but produces only a few weak byssal threads to aid in attachment and stabilization. Further stability within the substratum is obtained by adhesion of foreign particles, often forming a dense coat over the periostracum which adds to the surface area and weight of the bivalve (Prezant, 1979a, b, 1980). Ansell (1967) described the burrowing activities of L. norwegica (Gmelin) as very slow. Stanley (1970) concluded the same for L. hyalina. Obser- vations of L. californica, hyalina and floridana in the present study showed that these bivalves burrowed to their usual partially buried position within two to four minutes. They often travers- ed short distances while in the substratum, as revealed by numerous trails left in the sediment. All three species showed photosensitivity and responded to shadows by withdrawing their siphons and adducting their valves. Species of the more sedentary genus, Ento- desma, are usually found intertidally or just sub- tidally, nestled within rocky crevices or among algal holdfasts, tunicates or sponges. The genus possesses the largest individuals of the family and also the thickest shelled members. En- todesma, especially as juveniles, can adhere foreign particles to their shell but, unlike Lyon- sia, are attached by numerous, thick and strong byssal threads. The nestling habit of these bi- valves often produces distorted shells reflecting compressions or modifications of growth within their, often small, rocky crevices. This habit results in great variability in shell shape of in- dividuals in a given species, and makes shell form a difficult characteristic to use in species determination. The third lyonsiid genus, composed of a single known species, Mytilimeria nuttalli, has as- sumed a totally sessile life-style embedded within compound tunicates (Eudistoma psam- mion and Distaplia occidentalis) usually in the intertidal zone, although Smith and Gordon (1948) report finding this bivalve in depths of about 20 meters. The larvae of M. nuttalli in- itially settle upon and are eventually encased by the growing ascidian colony (Yonge, 1952). The clams maintain a narrow siphonal slit in the asci- dian test that is forced apart by protrusion of their siphons and seals tightly when the siphons Vol. 95(2) April 30, 1981 THE NAUTILUS 61 PERIOSTRACUM FOOT AND BYSSAL SYSTEM intertidal to deep benthic; partially buried in fine sands or muds thin radially spinulated; often sand covered; radial striae elongate with less than 1:2.5 umbonal length ratio; thin prismatic, biphasic nacre thin, non-muscular edge with numerous multi- cellular mantle glands opening into periostracal groove isomyarian to slightly heteromyarian active foot is long and laterally flattened; well developed byssal gland produces a few, thin byssi; pedal gape long and narrow with no internal rim narrow lumens; numerous, small variously colored, pigmented spots; numerous small photoreceptors on exhalent siphon ENTODESMA intertidal to subtidal; usually nestled in rocky crevices or among algal holdfasts, tunicates or sponges thick, wrinkled; may have partial extraneous cover; radial striae elongate with greater than 1:2.5 umbonal length ratio; often a thick homogeneous layer; always a thin pris- matic and biphasic nacre thick, muscular mantle edge with many mantle glands as juvenile that open distal to periostracal groove slightly heteromyarian small, cylindrical foot; well developed byssal gland produces many thick byssi ; pedal aperture is circular and has a raised internal rim very muscular with medium diameter lumens; no photoreceptors intertidal to just subtidal embedded within compound ascidians thin; golden brown; surface pitted with crater-like pores globular shell with less than 1:2.5 umbonal length ratio; thin homogeneous, thick prismatic, biphasic nacre muscular, deeply pigmented mantle edge; no arenophilic radial mantle glands heteromyarian small cylindrical foot; poorly developed byssal gland produces a few, thin byssal threads; small, circular pedal gape very broad si phonal no photoreceptors TABLE 1. Comparison of the major generic differences within the family Lyo7isiidae. LyonsiaarenosaMoWer, 1842 LyoTisia califomica Conrad, 1837 Lyonsiafloridana Conrad, 1849 Lyonsiagouldii Da\\, 1915 Lyonsia hyalina Conrad. 1831 Lyonsia norwegica Gmelin. 1791 Lyonsia puget£7is is Dall, 1913 Entodesma beana (Orbigny, 1842) Entodesma chilensis (Philippe, 1845) Entodesma cuneata (Gray , 1828) Entod£smafretalis{'D3[\, 1915) Entodesma patagonica (Orbigny, 1846) Entodesma saxicola Baird, 1863 Entodesma, truncatissima Pilsbury, 1865 My tilimeria nuttalli Conrad, 1837 1:1.9 1:2.1 1:1.9 1:1.3 1:1.5 1:1.6 1:1.5 1:5.9 1:6.7 1:4.8 1:4.7 1:3.8 1:2.8 1:4.6 1:1.6 TABLE 2. Average ratio of distance from umbo to anterior shell edge and posterior shell edge to umbo. Higher ratios mean greater distance from umbo to posterior edge than from imibo to anterior edge of shell. Measurements exclude any overlap of periostracum at the shell edge. are withdrawn. Mytilimeria iiuttalli, as a juvenile (Yonge, 1952) and when removed from its host as an adult, can produce a few thin, weak byssal threads. Based upon the globular shell shape, this species appears the least lyon- siid like, but shell ultrastructure and internal anatomy reveal that it is indeed a member of the Lyonsiidae. Detailed morphological differences between the three genera of Lyonsiidae are noted in the following definitions and in Tables 1 and 2. Systematics Family Lyonsiidae, Fischer, 1887 Shell typically inequivalve with left valve generally larger and extending slightly beyond right; shell usually with a weakly developed prismatic layer and a thick biphasic (lenticular plus sheet) nacre; periostracum often well de- veloped and extending beyond shell edge espe- cially in posterior region; internal resilium split by a well developed lithodesma; resilium pos- sesses a dense array of long, aragonitic needles which lie in a plane normal to hinge and litho- desma; mantle edges fused (Type C fusion (Yonge, 1957)) by the inner and middle folds leaving only four openings into the mantle cavity (inhalent and exhalent siphons, pedal aperture, fourth pallial atrium); mantle edge may possess discrete multicellular, club-shaped mantle glands which secrete a mucoid substance in conjunction with periostracum and function in adhesion of foreign particles to shell exterior; siphons short, split, with short fringes or ten- 62 THE NAUTILUS April 30, 1981 Vol. 95(2) FIGS. 1-6. 1, Lyonsia pugetensis, Sitka Harbor. Alaska: length = 2S mm. 2, Lyonsia californica, Venice, California; kmjth = 19 mm. 3, Lyonsia hyalina. Marthas Vineyard, Massachusetts; length = 17 rrmi. 4, Lyonsia floridana, Sanibel Island, Florida; length = 10 mm. 5, Entodesma saxicola, Friday Harbor, Washington; length = S9 mm. 6, Entodesma truncatissima, Hokkaido, Japan: length = 67 mm. Vol. 95(2) April 30, 1981 THE NAUTILUS 63 FIGS. 7-12. 7, Entodesma cuneata, Iquiqui. Peru: length=36 mm. 8, Entodesma patagumca, Punta Balneario. Argentina: length = 17 mm.. 9, Entodesma fretalis, Corral Bay, Chile: length =31 mm. 10, Entodesma chilensis, Corral Bay. Chile: length = -22 mm. 11, Entodesma beana, Myrtle Beach. South Carolina: length = 28 mm. 12, Mytilimeria nuttalli, Venice, California; length = 2i mm. 64 THE NAUTILUS April 30, 1981 Vol. 95(2) tacles; anterior few filaments of inner demi- branch of gill fused with inner portion of palp (Category II, Stasek, 1963); outer demibranch of gill composed of a single, upturned lamella (Type E, Atkins, 1937); Type IV stomach (Purchon, 1958, 1960); simultaneous herma- phrodites with large ova possessing numerous, thick gelatinous coats. Genus Lyonsia Turton, 1822 Figs. 1-4 Type Mya striata Montagu, 1815 ( =M. norwegica Gmelin, 1791). 1788 Mya Chemnitz, Conch. Cab. 10:345, pi. 170, figs. 1647- 1648. (non-binomial). 1802 Pandora Bosc, Hist. Nat. Coq. 2:243. Non Bruguiere, 1797. 1802 Pandore Bosc, Hist. Nat. Coq. 2:243, pi. 14, fig. 1. (error for Pandora). 1822 Lyonsia Turton, Conch. Insul. Brit. p. 35, pi. 3, figs. 6-7. 1827 Magdala, Brown, lUustr. Recent Conch. Great Brit., pi. 11, figs. 1, 2 and 10. 1827 Hiatella Brown, Illustr. Recent Conch. Great Brit., pi. 16, figs. 26-27. Non Bosc, 1801. 1830 Tetragonoste Deshayes, Encycl. Method., Vers 3:590. (vernacular name). 1833 Myatella Brown, Conch. Text-Book, p. 142, pi. 16. figs. 12 and 30. 1833 Pandorina Scacchi, Osserv. Zool., p. 14, Non Borg St. Vincent, 1827 (Protozoa). 1835 Osteodesma Deshayes, in Lamarck, Anim. s. vert., 2nd Ed., 6:85, 129. Non Blainville, 1825. 1926 Eudorina Pascher, Arch. Protestenk. 53:470-471. 1969 Arerwlyonsia Nordsieck, Die europaeischen Meere- smuscheln eis. Kapverden. Mittlemeer, Schwarzes Meer, p. 156. (Type: arenosa Moller, 1842). Shell elongate, inequilateral, posterior region from umbones usually longer and tapering to a truncated siphonal region; shell with siphonal gape; typically a dense cover of foreign ma- terial, usually sand, covering at least a portion of the shell's exterior; shell radially ornamented with numerous, small truncated spines; perio- stracum thin with fine radial striations and adherent mucoid strands emanating from man- tle edge; small but prominent lithodesma; pris- matic shell layer thin and lenticular and sheet nacre layers well developed; ratio of distance from umbo to anterior edge and umbo to poster- ior edge usually around 1:2.5; anterior/posterior shell axis parallel to body axis (measured from dorsal edge of adductor muscles); mantle edge and siphons thin and nonmuscular; band of nu- merous, small darkly pigmented photoreceptor organs present on exhalent siphon; arenophilic mantle glands numerous, lining most of mantle edge at regular intervals and secreting a mucoid product into the periostracal groove and over the periostracum; periostracal groove well defined; unfused portions of mantle edge reveal typical three-fold edge; pedal aperture long, narrow and lacking internal rim; foot long, laterally flattened, active with well developed byssal gland producing only a few, fine byssal threads; isomyarian to slightly heteromyarian; adductor scars poorly delimited on shells; shallow burrowers in fine sands or muds. Entodesma Philippi, 1845 Figs. 5-13 Type Entodesma chilensis Philippi, 1845. 1818 Mya Lamarck, Anim. s. vert. 5:461. (in part). 1830 Tetragonoste Deshayes, Encycl. Method., Vers 2:590. (vernacular name). 1835 Osteodesma Deshayes in Lamarck, Anim. s. vert., 2nd Ed. 6:75, 84. 1845 Entodesma Philippi, Arch. Naturgesch. 2:52, 53. 1849 Tetragostea Herrmannsen, Index Genera Moll. 2:565. 1909 Agriodesma Dall, Proc. U.S. Nat. Mvs. 37:284. Thick-shelled bivalves with a thick, often brown or green, periostracum; valves commonly crack when dried; lithodesma large; periostra- cum often with radial striations; typically rock crevice or algal holdfast dwellers that may con- form to shape of nesting site; shell often with byssal notch located posterio-ventrally; anter- iorrposterior length ratio from umbones greater than 1:2.5; adult shells often with thick, outer granular homogeneous layer, always with a weak prismatic and biphasic nacre; anterior/ posterior body axis not parallel to shell longi- tudinal axis; mantle edge and siphons extremely muscular; arenophilic radial mantle glands usually present in juveniles where they open distal to the periostracal groove; arenophilic mantle glands may gradually be lost with growth; inner mantle epithelium densely packed with mucocytes; periostracal groove and mantle folds poorly defined; siphons often brightly col- ored and lacking photoreceptors; foot small, cylindrical with well developed byssal gland pro- ducing numerous thick, strong threads; pedal Vol. 95(2) April 30, 1981 THE NAUTILUS 65 gape small, circular with raised internal rim; muscle scars usually well defined; slightly heteromyarian with anterior adductor smaller than posterior adductor and displaced ventrad; some indication of temporary marsupium in suprabranchial chamber. Genus Mytilimeria Conrad, 1837 Fig. 14 Type Mytilimeria nutfalii Conrad, 1837. 1837 Mytilimeria Conrad. Journ. Acad. Nat. Sci. 7:246- 247, pi. 19, fig. 5. Thin-shelled bivalves with rounded shells; um- bones may be slightly recurved; periostracum thin and often light golden-brown color; no radial ornamentation but periostracum covered with numerous small, crater like pores; usually embedded within compound tunicates; perio- stracum firmly attached to ascidian host and often peels away when the clam is removed from the tunicate; lithodesma short, squat; anterior:posterior umbonal length ratio usually less than 1:2.5; adult shells with thin homogeneous layer, well-developed prismatic layer and a biphasic nacre; anterior/posterior body axis oblique to shell longitudinal axis; mantle edge broad and flat with well developed orbital musculature; mantle edge contains a deep purple pigment; lacks mantle glands; si- phons muscular with wide atrial diameters and no photoreceptors; siphons with numerous api- cally situated and brightly pigmented short fringes, often appearing to match coloration of host tunicate; inner mantle epithelium with a dense array of mucocytes; foot very small, cylin- drical with poorly developed byssal glands able to produce only a few thin byssal threads; pedal aperture very small, circular; heteromyarian with anterior adductor small and displaced ven- trad. Entodesma beana (Orbigny, 1842) new combination Figs. 11. 13 1845 Lyonsia beana Orbigny, Sagra, Hist. Cuba, Moll. 2: 225, pi. 25, figs. 26-28. 1850 Lyonsia braziliensis Gould, Proc. Boston Soc. Nat. Hist. 3:219. 1857 Osteodesma orbigny Fischer, Journ. Conchyl. 11:383, pi. 11, figs. 7-8. 1928 Lyonsia beana Lamy, Journ. Conchyl. 72:2.58. fa id FIG. 13. Entodesma beana soft part morphology. While still listing it as Lyonsia beana (sub- genus Philippia), Abbott (1974) suspected that this "may be an Enfodesyna." Moore (1969) noted that the type for Philippina (placed within En- todesma) is Lyonsia beana. Many characteris- tics of this species immediately remove it from Lyonsia and place it in the redefined genus En- todesma. The overall shell shape is entodesmid; that is, it is anteriorly gently tapered to a round- ed edge with the umbo located very close to the anterior of the shell. The posterior end of the shell is broad and truncate and the anterior/ posterior length ratio form the umbo is close to 1:6. The periostracum is thick, brown and wrin- kled in places (especially posteriorly), and there is rarely a partial sand cover on the shell. The ventral edge of the shell has a shallow byssal notch. Juvenile shell consists of a thin prismatic layer and a thick sheet nacre (Prezant, 1980b). The apparent lack of a lenticular nacre in juveniles is a rare modification of lyonsiid shells. Larger specimens of E. beana possess a typical biphasic nacre (i.e., composed of lenticular plus sheet nacre). There are several weak radial striations aligning the shell. Muscle scars are well defined on the internal shell. The litho- desma is long and narrow. The mantle edge of E. beana is muscular with dense bundles of oribtal muscles. The fourth pallial artrium is extremely small and difficult to discern but is located directly beneath the pos- terior adductor muscle. Arenophilic mantle glands line a part of the mantle edge in juve- 66 THE NAUTILUS April 30, 1981 Vol. 95(2) niles, usually along the posterior pedal gape and the siphons, and open distal to the periostracal groove. Specimens examined (NMNH) from Cape Hatteras, North Carolina, southward to the coast of Brazil, were found in algal or seagrass beds, in gravel or associated with sponges or coelenterates. Many of these specimens had a partial sand cover near the byssal notch or near the posterior shell region. This sediment coat correlates well with the loca- tion of the mantle glands. The small, wormlike foot expands dorsally in- to a distended region with a very large, circular byssal orifice. The byssal groove runs almost the entire length of the posterior side of the foot. A small, circular pedal aperture is present and has a distinct, raised internal rim. E. beana is heteromyarian with a small anterior adductor muscle located ventrally, below the anterior part of the ctenidia. The anterior adductor muscle is narrow and situated in an oblique position along the ventral cur- vature of the anterior shell edge. The posterior adductor muscle is about twice as large as the anterior adductor and is oval in sagittal section. The former is situated well away from the shell edge while the anterior adductor is located very close to the shell edge. The muscular siphons lack photoreceptors but are well endowed with numerous, small ten- tacles. In one specimen the narrow suprabranchial chamber was densely packed v/ith numerous, large eggs. During the study this has also been observed in E. chiiensis and E. saxicola. This finding may be indicative of a temporary mar- supium in some species of Entodesma. Entodesma fretalis (Dall, 1915) new combination Figs. '.>. 11 1915 Lymsia fretalis Dall, Proc. U.S. Nat. Mus. 49:454. The type locality for this species is the Straits of Magellan at a depth of about 38 meters (Dall, 1915). The type description of the species cor- responds with the generic redefinition offered here and, indeed, Eydodesrrm fretalis and E. chiiensis are quite similar. In all specimens recently examined, shells are distinctly ento- FIG. 14. Entodesma fretalis soft part morphology. desmid. The valves are only slightly tapered anteriorly but are broad and truncated poster- iorly. The average umbo length ratio is 1:4.6, the umbo being located very close to the an- terior edge. The periostracum is ornamented with several raised radial striations and is usually thick and brown, and extends beyond the shell edge (es- pecially posteriorly). The shell proper is com- posed of thin prismatic, thick lenticular, and thick sheet nacre in juvenile specimens. Large adult shells have not been examined ultrastruc- turally. The lithodesma is large, usually about 1/5 the shell length. The mantle edge is highly muscular, especially with radial musculature. The inner mantle epithelium is densely packed with mucocytes. Many arenophilic radial mantle glands are pre- sent in juveniles which open distal to the perio- stracal groove. Secretion from these glads pene- trates the periostracum, and there is sporadic, partial sand adhesion on some shells. A small fourth pallial atrium is present directly beneath tlie posterior adductor muscle. The foot is very small and appears to be dorso- ventrally compressed in preserved specimens. There is a very large byssal orifice and a well defined byssal groove which runs almost to the tip of the foot. The small, circular pedal aper- ture has a raised internal rim. Entodesma fretalis is heteromyarian with the posterior adductor being about IV2 times the Vol. 95(2) April 30, 1981 THE NAUTILUS 67 size of the anterior adductor. The anterior ad- ductor is also displaced ventrally so that the dor- sal edge of the latter is aligned with the ventral edge of the posterior adductor. Thus the body axis is oblique to the shell longitudinal axis. The anterior adductor is also compressed in the anterio-posterior plane. The siphons of this species are very muscular and are apically covered with a dense array of short, frilly tentacles. There are no photorecep- tors on the siphons. Dissection of several specimens revealed densely packed ova within the suprabranchial chamber similar to conditions found in En- todesma beana and E. saxicola. The eggs seem to align neatly along the branchial filaments. Entodesma cuneata (Gray, 1828) Fig. 7 1828 Anatina cuneata Gray, Spicilegia Zoologica 1:6, pi. 3, fig. 12. 1843 Osteodesma cuneata Hanley, Cat. Recent Bivalve Shells: 25. 1843 Osteodesma cuneata Deshayes. Treat, elem. Conch. 1:215, pi. 9, figs. 7-8. 1846 Lyonsia cuneata Orbigny, Voy. Amer. merid 5(Moll.): 518. 1856 Mytilimeria cuneata H. and A. Adams. Gen. Recent Moll. 2:364. 1907 Lyonsia cuneata Mehdll and Standen, Mar. Moll. Scot- tish Nation. Antarct. Exped., Trans. R. Soc. Edinburgh 46:151. 1909 Entodesma cuneata Dall, Shells Peru, Proc. U.S. Nat. Mus. 37:259. 1914 Lyonsia cuneata Melvill and Standen. Ann. Mag. Nat. Hist. 13(8): 136. 1928 Lyonsia (Entodesmu) cuneata Lamy, Journ. Conchyl. 72:256. 1951 Entodesma cuneata Carcelles and Williamson, Rev. Inst. Nac. Inv. Cienc. Nat. 2:348. 1972 Entodesma cuneata Dell, Recs. Dominion Mus. 8(3): 29, fig. 23. Dall, (1909), on the basis of shell characteris- tics, was the first to place Lyonsia cuneata in Entodesma. Soft parts have not been examined, but shell ultrastructure (Prezant, 1981) appears to substantiate this generic change. Large speci- mens of E. cuneata have a thick brown perio- stracum which is often frayed and wrinkled (es- pecially posteriorly). The shells have a thick, well developed granular homogeneous layer lo- cated above a poorly developed prismatic layer and a biphasic nacre. There is a large, recurved lithodesma. Dall (1910) synonymized Entodesma cuneata and E. chilensis on the basis of reports of other authors but retracted this synonymy in his review of some Anomalodesmata (1915) where he states that E. chilensis and E. cuneata are "very different" shells. As Dell (1972) points out, entodesmids are typically found nestled within rocky crevices and their growth form conforms to their surroundings. Thus species of En- todesma can vary in shape according to their habitat. However, distinct differences in length to umbo ratios, and the broad, round posterior margin in E. chilensis as compared to the long, tapering, truncated siphonal margin in E. cuneata, indicates these are separate species. A detailed examination of soft parts oiE. cuneata is still a necessity. Entodesma patagonica (Orbigny, 1846) Fig. 8 1846 Lyonsia patagonica Orbigny, Voy. dans I'Amer. Merid. 5:517, pi. 81, figs. 13-14. 1915 Lyonsia patagonica Dall, Proc. U.S. Nat. Mus. 49: 454. 1928 Lyonsia patagonica Lamy, Journ. Conchyl. 72:258. 1944 Lyonsia patagonica Carcelles, Rev. Mus. La Plata 3:292, pi. 14, fig. 113. 1967 Lyonsia patagonica Castellanos, An. Com. Inv. Cient. Buenos Aires 8:280, pi. 24, figs. 11-12. 1972 Entodesma patagonica Dell, Recs. Dominion Mus. 8(3):31, fig. 26. In his 1915 work on the Anomalodesmata of the west coast of America, Dall again wrote that Lyonsia patagonica "is probably an Entodesma". Dell (1972) examined the type specimens at the British Museum of Natural History and confirm- ed this diagnosis on the basis of gross shell mor- phology. Juvenile shells of this species have a thin prismatic layer and a biphasic nacre. There is a long, thin lithodesma. The umbonal length ratio of this species is about 1:3.8 and thus fits the Eyitodesma pattern well. The soft parts of this species also confirm its identity as an En- todesma. The mantle edge and siphons are highly muscular. There are no photoreceptors. Mantle glands are numerous in juveniles and open distal to the periostracal groove. A small fourth pallial atrium is present below the 68 THE NAUTILUS April 30, 1981 Vol. 95(2) posterior adductor. In this species the fourth atrium has a slightly raised internal rim. The foot is small and cylindrical, and has a very large byssal orifice. The pedal aperture is small and circular and has a well defined raised internal rim. The species is slightly heteromyarian with a large, circular, posterior adductor muscle (in sagittal section) and a smaller, ovoid, anterior adductor which is slightly ventrad. DISCUSSION The taxonomic development of the family Lyonsiidae reflects the gradual accumulation of data on these bivalves and the incorporation of these data into the groups' systematics. Dall (1903) originally placed only the genus Lyonsia in the lyonsiids with two subgenera: Lyonsia s.s. and Entodesma, with the latter divided into two sections, Allograma (Dall, 1903) and Philippina (Dall, 1900). In 1915, Dall gave Allograma sub- generic status and added Agriodesma as a sec- tion of the subgenus Entodesma. Conrad (1837) thought Mytilimeria was allied with the my- tilids but Dall (1915) tentatively placed the genus Mytilimeria in the Lyonsiidae. Habe (1952) gave generic status to Allograma with Bentholyonsia as a subgenus. Habe (1977) divid- ed the Japanese Lyonsiidae into four genera: Lyonsia, Allograma. Bentholyonsia and Agrio- desma. It is apparent thai Allograma, described by Habe (1977) and Dall (1903) as being very thin shelled and having fine radial striations over the shell, short siphons with numerous fringes or tentacles, anterior-posteriorly elongated shell with a circular anterior end and an elongated posterior end with a siphonal gape, is not separable from Lyonsia as here defined. The umbones are also situated close to the mid- point of the longitudinal axis of the shell (um- bonal length ratio of about 1:1.2). Allograma certainly does not belong as a subtaxon of the thicker shelled, more heterogeneously shaped and more posteriorly drawn out Entodesma and characteristics oi Allograma are not sufficient to warrant generic status. Taxonomic charac- teristics of species oi Allograma overlap exten- sively with characteristics of Lyonsia and these bivalves should therefore be transferred to the latter genus. A similar situation exists for Bentholyonsia, originally described by Habe (1952). Habe (1977) described this genus as very thin shelled, ovoidal ellipsoidally shaped, with a circular anterior end, and a straight wider posterior end with a siphonal gape, having a shell with fine radial ribs, a glossy shell interior, and found living on fine sands. Moore (1969) maintains subgeneric status for Bentholyonsia on the basis of radially arranged granules on the shell's exterior, a lack of radial ribs, a posterior shell gape and a large lithodesma. The apparent conflict concerning radial ornamentation may indicate poor defini- tion of terms, condition of material, or a vari- able character not valid in diagnosis at or above the species level. The overall definition never- theless fits the genus Lyonsia well. The umbo is situated centrally in Bentholyonsia and approx- imates a 1:1 umbonal length ratio. Species of Bentholyonsia should be transferred to Lyonsia. Species of Agriodesma on the other hand should be allocated to Entodesma. This relation- ship was recognized by Abbott (1974) when he placed Agriodesma as a subgenus oi Entodesma. The umbonal length ratios of Japanes species of Agriodesma. described by Habe (1977) range from 1:3.8 to 1:5.6, obviously within the Ento- desma range. Habe (1977) defined individuals in this "genus" as medium to large in size, having an anteriorly situated umbo, radial ribbing of the shell, thick brown periostracum in larger specimens, commonly ovoidal ellipsoid, poster- ior end of shell wide and straight, having a glossy interior, and often living among the roots of seaweeds. This same author tentatively syno- nymized E. truncatissima with A. naviculum (A. Adams and Reeve, 1850). The use of subgenera or sections for lyonsiids by many early authors (Lamy, 1928; Dall, 1909, Thiele, 1935) and continued by Keen (1971) and Abbott (1974) in their comprehensive volumes on American molluscs, breaks the family down into several minor components which only serve to confuse the taxonomy. These subdivisions are Imsed upon variable characteristics, such as periostracal color and surface topography (i.e., the subgenus Agriodesma Dall, 1909 of the Vol. 95(2) April 30, 1981 THE NAUTILUS 69 genus Entodesma. is distinguished from Ento- desma s.s. by its coarse periostracum, and the subgenus Phlycticoncha Bartsch and Rehder, 1940 ( = Phlyctiderma. 1939) may have a zigzag coloration of the thin periostracum). The vari- ability in color morphs and periostracal or- namentation or thickness, which are often worn smooth due to abrasion or growth habits, render these distinctions unreliable. Within the Lyon- siidae, divisions between the three marine genera are clear, and the variability within a given species sufficient to warrant the disuse of subgeneric taxa and use only of generic and specific ranks. Definitions offered in this paper should be ap- plicable to all marine lyonsiids. It is important to note that there is a strong association between internal anatomy, ecology, and shell structure; for example, the overall modification of shell gape corresponds well with the degree of he- teromyarianism and changes of habitat. As in mussels, increased dependence upon a byssal system results, in evolutionary terms, in ex- panded importance of the posterior region of the bivalve, i.e., the siphonal area and associated shell and structures. Increased stabilization and decreased exposure resulting from firm byssal attachment within crevices resulted in a more pronounced elaboration of the posterior region of species of Entodesma than in Lyonsia. Yonge (1952) cites these differences as extending inter- nally to include the adductor muscles, and leading, in part, to the more pronounced hetero- myarian condition found in Entodesma. The elaboration of the siphonal area has resulted in a hypertrophy of the active posterior region. Par- tially because of the endosymbiont habit that results in external well distributed support, Mytilimeria nuttalli has assumed a circular or globular shape. Taxonomic definitions of the marine genera offered here reveal a plasticity of the Lyonsiidae that partially accounts for their phylogenetic and ecologic divergence. The slender shell and relatively active pedal system of Lyonsia are well adapted for burrowing. The weak byssal system is supplemented by the extraneous sand coat on their shells, and this adhesion is sup- ported by the mucoprotein produced by the arenophilic mantle glands (Prezant, 1979a). The mucoid secretion adheres firmly to the perio- stracum and is entangled among the numerous shell spinules (Prezant, 1979b). The high nacre content of the shell allows the valves to remain thin yet strong and fracture resistant. Light- shadow reactive siphonal photoreceptors serve the bivalve in detecting large predators in shallow waters, and also in the detection of light-dark cycles. The adaptive significance of the shell ultrastructure is discussed elsewhere as is the role and phylogenetic implications of the arenophilic radial mantle glands (Prezant, 1980; 1981). Many species of Entodesma have assumed a life-style nestled within crevices along a rocky intertidal shoreline. These bivalves are often ex- posed to harsh physical stresses from tidal im- pacts and have developed a thick periostracum and shell and an energetically inexpensive, frac- ture resistant, homogeneous layer (Prezant, 1981). Thick byssal threads help secure the ani- mal in place. A reduction in the number of are- nophilic radial mantle glands occurs with growth and increased shell thickness. The nest- ling habit probably affords protection from some potential predators. Entodesma lacks photoreceptors but the nestling habits may leave the bivalve in poorly lit areas anyway. Mytilimeria lacks photoreceptors, an active byssus, arenophilic radial mantle glands, and possesses a very thin shell. These characteristics fit the bivalves well in their endosymbiont habit. The enveloping ascidian has coincidentally assumed the role of stablizing, protecting and camouflaging the bivalve. In turn Mytilimeria has developed wide siphonal atria, cryptic col- oration of siphons to match their host test, and a physically adhesive periostracum which binds the bivalve tightly to the tunicate. Yonge (1952) believed that the byssus of adult Mytilimeria nuttalli had regressed to the point of nonfunction, although he did note byssi in juveniles. This was a reasonable assumption for adult clams since it is difficult to find even rem- nants of byssi within the tunicate. Furthermore there appears to be little need of a byssus for a bivalve dwelling within a sessile ascidian. Adult M. nuttalli, however, when placed outside their 70 THE NAUTILUS April 30, 1981 Vol. 95(2) hosts will produce a few thin byssal threads reminiscent of those in Lyonsia. Both of these genera have developed other extraneous modes of stabilization. Entodesma, on the other hand, exposed to the rigors of intertidal, often rocky shorelines, has evolved a system of numerous, strong byssal threads and a thick shell and periostracum. Coe (1943) in a discussion of functional her- maphroditism among bivalves noted that most hermaphrodites are also brooders. In three spe- cies of Entodesma (saxicola, chiieyisis and fretalis) numerous ova have repeatedly been found within the suprabranchial chamber of the gills. It is uncertain if this represents true brooding, or is the result of some environmental or preservation artifact that caused expulsion of ova into this cavity. Eggs are exceptionally large in some Anomalodesmata (Morgan and Allen, 1976), and larvae may have a short larval existence. Brooding seems reasonable since many species of Entodesma live in a rigorous environment in which larvae, even if present in the plankton for a short time, may quickly be washed into a zone without appropriate sub- strata for settlement. If released in a late stage of development, larvae may be able to settle quickly out of the water column within a single tidal cycle and remain within a suitable environ- ment. Eggs examined in these three species, however, did not show any signs of develop- ment, and, indeed, may not have been fertilized. It may be possible that the suprabranchial chamber acts as a holding chamber prior to in- ternal fertilization. In this way gametes may not be washed away prior to fertilization. The repro- ductive and life cycles of species of Entodesma have yet to be examined. Morrison (1943) described Guianadesma simiosum and placed this freshwater bivalve in the Lyonsiidae. Morrison (1943) reported G. siniiosum as having a small, cylindrical foot, with a large byssus gland and a large byssal orifice; being slightly heteromyarian with a larger posterior adductor; having fused mantle lobes except for the siphonal and pedal aper- tures; with papillose siphons; well developed brown periostracum; small, rhomboidal, inequi- valve shell; being edentulous; having rounded anterior end and truncate posterior end; raised radial striations; umbones about one-third from anterior end; and internal ligament lacking a lithodesma. These molluscs were found attached by byssal threads to rocks in midstream of the Cuyuni River, Guyana. Specimens personally examined (ANSP) appeared "Entodesma" like, as did the shell description offered by Morrison (1943). Muscle scars were well imprinted on the shell interior, and the umbonal length ratio was about 1:3.5. The periostracum appeared clean (i.e., no adhering sediments) in specimens ex- amined including the type specimens (NMNH -J. P. E. Morrison, personal communication). The gonadal and gill structures, presence of arenophilic mantle glands, and shell ultrastruc- ture are presently unknown and these must be examined prior to final taxonomic categoriza- tion. The evolutionary modifications and adapta- tions within the Lyonsiidae have resulted in three distinct marine genera, readily separable and easily characterized, and well suited to the diverse habitats in which they occur. Because of the distinct tripartite divergence revealed in this taxonomic analysis, subgeneric taxa for the marine Lyonsiidae should be abandoned. ACKNOWLEDGMENTS Thanks are extended to the following in- dividuals for the loan or donation of many speci- mens used in this study: Dr. J. A. Allen, Univer- sity Marine Biological Station Millport; Dr. F. Bernard, Pacific Biological Station; Dr. K. Boss, Museum of Comparative Zoology, Harvard Uni- versity; Dr. D. D. Chivers and Dr. W. Lee, California Academy of Sciences; Dr. G. Davis, Academy of Natural Sciences of Philadelphia; R. Dillon, University of Pennsylvania; R. Fay, Pacific Bio-Marine Labs., Inc.; Dr. R. Fernald, Friday Harbor Laboratories, University of Washington; C. Gallardo, Instituto de Zoologie, Universidad Austral de Chile; Dr. J. H. McLean, Los Angeles County Museum of Natural His- tory; Dr. J. Rosewater, National Museum of Natural History, Smithsonian Institution; and Dr. R. Virnstein. Harbor Branch Foundation, Inc. Vol. 95(2) April 30, 1981 THE NAUTILUS 71 I am most grateful to Drs. R. T. Abbott, M. R. Carriker, F. C. Daiber, R. E. Hillman, N. W. Riser, and J. Rosewater for encouragement and critical review of manuscript. Thanks also to F. Prezant for encouragement and help in collect- ing many of the live specimens used in this study and P. Savage for typing the manuscript. LITERATURE CITED Abbott, R. 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Systematics of Mollusca in Japan, Bival- via and Scaphopoda. Hokuryukan, Tokyo, i-xiii -i- 373 pp., illus. Neumayr, M. 1884. Zur morphologie des Bivalvenschlosses. S. B.AI^ad. Wiss. Wien 88(1):.385-418. Newell, N. D. 1965. Classification of the bivalvia. American Mus. Novitates 2206:1-25. Obigny, A. d'. 1843-1847. Mollusques. Quatrieme classe. Lamellibranchia. Paleont. Francaise. Terrains cretaces. 3: 807 pp. 1846. Voyage dans VAmerique Meridional . . ., Mollusques. V(3):489-758. Atlas, IX (Mollusques), lams. 1-85. Paris. Pelseneer, P. 1889. Sur la classification phylogenetique des pelecypodes. Bull. Sci. Fr Belg. 20:27-52. Philippi, R. A. 1845. Diagnosen einiger neuen Conchylien. Arch. Naturgesch. 11:50-71. 1853. Handbuch der Conchliologie und Malaco- zoologie. Halle. 547 pp. Prezant, R. S. 1979a. The structure and function (if the radial mantle glands of Lyonsia hyalina (Bivalvia: Anoma- lodesmata). Jour. Zool., Lond. 187:50.5-516. 1979b. Shell spinules of the bivalve Lyonsia hyalina. The Nautilus 93:93-95. 1980. The arenophilic radial mantle glands of the Lyonsiidae (Bivalvia: Anomalodesmata) with notes on lyonsiid evolution. Malacologia 20:267-289. 1981. Comparative shell ultrastructure of lyonsiid bivalves. The Veliger 23:289-299. Purehon, R. D. 1958. The stomach in the Eulamellibranchia: Stomach type IV. Proc. Zool. Soc. Lond. 131:487-525. 1959. Phylogenetic classifications of the Lamel- libranchia, with special reference to the Protobranchia. Proc. Malac. Soc. Lond. 33:224-230. 1960. The stomach in the Eulamellibranchia; Soc. Geol. Fr 12(4):419-467. Stomach types IV and V. Proc. Zool. Soc. Lond. 135: 431-489. Ridewood, W. G. 1903. On the structure of the gills of the Lamellibraneliia. Phil. Trans. Roy. Soc. Lond, 195: 147-284. Smith, A. G. and M. (Gordon. 1948. The marine mollusks and brachiopods of Monterey Bay, California, and vicinity. Proc. Calif Acad. Sci. 26:147-245. 72 THE NAUTILUS April 30, 1981 Vol. 95(2) Stanley, S. M. 1970. Relation of shell form to life habits of the Bivalvia. Geol. Soc. Am. Mem. 125, 296 pp. Stasek, C. R. 1963. Synopsis and discussion of the ctenidia and labial palps in the bivalved mollusca. Veliyer 6:91-97 . Thiele, J. 1935. Handbuch der systematixchen. Weichtier- kunde. Jena: Teil 3. Ciassis Bivalvia. i-v + 779-1154 pp. Gustav Fischer. Turton, W. 1822. Conchylia insularu.7n Brittanicarum. The shells of the British Islands: reissued as Bivalve shells of the British Islands. 1830. London M. A. Nattali; 279 pp. Yokes, H. E. 1980. Genera of the Bivalvia; A systematic and bibliographic catalogue. Paleont. Research In.st. Ithaca, N.Y., 307 pp. Yonge, C. M. 1952. Structure and adaptation in Entmlesmn saxicola (Baird) and Mytiliineria nuttalli Conrad. Univ. Cal. Puhl. Zool. 55(10):439-450. 1957. Mantle fusion in the Lamellibranchia. Publicaz. Staz. Zool. Napoli 29:151-171. Abbreviations Used in Drawings aa- anterior adductor muscle d -digestive diverticula t e-exhalent siphon f-foot fa -fourth pallial aperture i - inhalent siphon id - inner demibranch ip- inner labial palp k- kidney ud- outer demibranch op -outer labial palp ov - ovary p;i- posterior adductor muscle pc- pericardial chamber pg- pedal gape r- rectum t- testis A NEW GENUS OF TURBINELLIDAE (GASTROPODA: PROSOBRANCHIA), WITH THE DESCRIPTION OF A NEW SPECIES FROM THE CARIBBEAN SEA James F. Quinn, Jr. Florida Department of Natural Resources Marine Research Laboratory 100 Eighth Ave., S.E. St. Petersburg, FL 33701 ABSTRACT Cyomesus, a new genus, is proposed to receive four species of Turhinellidae previously assigned to Mesorhytis Meek. 1876, Teramachia Kuroda. 1931. and Benthovoluta Kuroda and Habe, 1950. All four species are reviewed, and a new species, Cyomesus aratiunculus, is described from, near the Virgin Islands. Investigations of the tropical Atlantic and eastern Pacific deep-sea by the University of Miami have resulted in one of the most exten- sive collections of tropical deep-sea mollusks in the world. Most of this remarkable assemblage remains to be examined. These collections con- tain specimens of three of the four western Atlantic species of Cyomesus, a previously undescribed genus. Since the species here assigned to Cyomesu^s have been the subject of much nomenclatural confusion, a review of all species is presented. The taxonomic history of the genus is reviewed and the relationships of Cyomesus to other genera within the Turhinel- lidae are briefly discussed. Specimens on which this paper was based are housed in the Invertebrate Research Collection of the Rosenstiel School of Marine and Atmos- pheric Science, University of Miami (RSMAS), designated by the abbreviation UMML, the Na- tional Museum of Natural History, Smithsonian Institution (USNM), and the Museum of Com- parative Zoology, Harvard University (MCZ). Family Turhinellidae Swainson, 1840 Subfamily Ptychatractinae Stimpson. 1865 Cyomesus gen. nov. Mesorhytis: Dall, 1889a: 172; 1889b; 112; 1890; 317. -John- son, 1934; 127.-Cernohorsky, 1970; 51; 1972; 218. {Non Mesorhytis Meek, 1876: 356, 364). Prodallia Bartsch, 1942; 12 (partim). Teramachia: Weaver and duPont, 1970: 176 (partim). - Bayer. 1971: 195. -Abbott, 1974; 243. {Non TeraTnachia Kuroda. 1931; 45). Vol. 95(2) April 30, 1981 THE NAUTILUS 73 Benthmmluta: Rehder, 1972: 7, 8 (parHm). -Cernohorsky, 1973: 126 (parUm). Type-species -Fasciolaria (Mesorhytis) Meeki- ana Dall, 1889; herein designated. Gencfer- Masculine. Description -SheW fusiform, elongate, of moderate size; spire extended, 40-50% of total shell height. Whorls broadly rounded peripher- ally, constricted anteriorly; siphonal canal rela- tively short, broad, slightly reflexed. Sculpture on early whorls of strong axial ribs, usually be- coming obsolete on later whorls; spiral sculpture present or absent. Aperture lanceolate, outer lip slightly flared anteriorly in adult. Columella slightly flexed, with 3 high, thin, oblique plaits, posteriormost strongest; parietal wall with very thin glaze. Operculum small, thin, spatulate, slightly curved, with terminal nucleus. Radula triserial; rhachidian multicuspid, with saddle- shaped base; laterals with elongate base and distal, clawlike cusp. Remarks -The species here assigned to Cyomesus have been placed previously in Mesorhytis Meek, 1876, Teramachia Kuroda, 1931, and/or Benthovoluta Kuroda and Habe, 1950. Teramachia has usually been accepted as a member of the Volutidae. The uniserial radula of the type-species, T. tibiaeformis Kuroda, 1931 (illustrated in Habe, 1952), indicates close relationship with Calliotectum Dall, 1890, a volutid (Rehder, 1972; Cernohorsky, 1973). Since Bayer (1971) showed that Mesorhytis meekiana Dall, 1889, and Terarmackia chaunax Bayer, 1971, are turbinellids, Teramachia is eliminated as an appropriate genus for the pre- sent group. Mesorhytis was erected by Meek (1876) for a fusiform gastropod fossil from the Cretaceous of Missouri. An examination of the type series of M. gracilenta Meek, 1876, showed that Cyo- mesiis differed in having less prominent axial sculpture, the whorl periphery more anterior, the columella distinctly twisted to the left anteriorly (not straight), and the columellar plaits more lamelliform, with the posterior (not middle) plait most prominent. However, in view of the general similarity of Mesorhytis and Cyomesus, it is quite possible that Mesorhytis is turbinellid rather than fasciolariid as it has been regarded by most authors (Meek, 1876; Dall, 1889a, 1889b, 1890; Thiele, 1929; Cernohorsky, 1970, 1972) and may be a precursor of Bentho- voluta or Surculina Dall, 1908. Benthovoluta was introduced by Kuroda and Habe (1950) for Phenacoptygma? kiiensis Kuroda, 1931. Kuroda (1965) and Rehder (1967) showed that Benthovoluta was turbinellid in af- finity rather than volutid. Rehder (1967) also commented on the relationships of Metzgeria Norman, 1879, Ptychatractus Stimpson, 1865, and Surculina Dall, 1908, grouping them together with Benthovoluta. In a subsequent paper, Rehder (1972) discussed "Teramachia" barthelowi (Bartsch, 1942) and concluded that it should be assigned to Benthovoluta. He went on to mention Bayer's (1971) discussion of the Car- ibbean species Mesorhytis meekiana. M. costatus Dall, 1890, and Teramachia chaunax, and in- timated that these species constituted a distinct group of their own, but stopped short of sepa- rating them from Mesorhytis. Cernohorsky (1973), apparently unaware of Rehder's (1972) paper, independently placed Teramachia barthelowi in Benthovoluta. but, unlike Rehder, also included T. chaunax. Mesorhytis meekiana, and M. costatus. The relatively large shell with rounded whorls, very long, straight siphonal canal, and low, rounded columellar plaits of Ben- thovoluta distinguish it from Cyomesus, and, in my opinion, exclude "Teramachia" barthelowi from Beyithovoluta. I thus include the following genera in the Ptychatractinae in accordance with Rehder (1967) and Cernohorsky (1973) and with the changes involving Mesorhytis and Cyomesus discussed above: Ptychatractus Stimpson, 1865; Metzgeria Norman, 1879; Mesorhytis Meek, 1876; Benthovoluta Kuroda and Habe, 1950; Surculina Dall, 1908; Cyomesiis gen. nov.; and Ceratoxancu^ Kuroda, 1952 (fide Cernohorsky, 1973). Although problematical, the following fossil genera might also be considered turbinel- lid: Paleofusimitra Sohl, 1963, Mitridomus Sohl, 1963, and Fusimitra Conrad, 1855. Cyomesus meekianus (Dall, 1889) Fig. 1 Fa-sciolaria (Mesorhytis) Meekiana Dall, 1889a: 172, pi. 36, fig. 7; 1889b: 112, pi. 36, fig. 7. Fnsciolari.a (Mesorhytis) meekiana: Johnson, 1934: 127.- Rehder. 1972: 8. 74 THE NAUTILUS April 30, 1981 Vol. 95(2) Mesorhytia Tneekiana: Cernohorsky, 1970: 52; 1972: 218. Teramachia meekiana: Bayer, 1971: 197, figs. 54 (left), 5.5 D-E. Benthovoluta meekiana: Cernohorsky, 1973: 127, fig. 2. Description -See Bayer, 1971. Lectotype -USNM 86970; herein designated. Length 15.4 mm; width 5.2 mm. Type-locality -BLAKE sta. 100, off Morro Light, Havana, Cuba, 732 m; herein restricted. Material examined -BLAKE sta. 100, off Morro Light, Havana, Cuba, 732 m; 1 spec, USNM 86970 (lectotype); 1 spec, USNM 784568 (paralectotype).- BLAKE sta. 16, 23°irN, 82°23'W, 534 m; 1 spec, MCZ 7243 (paralec- totype). - BLAKE sta. 20, 23°02.5'N, 83°11'W, 402 m; 1 spec, MCZ 7242 (paralectotype). - PILLSBURY sta. P-1225, 17°42.5'N, 77°58'W, 457-558 m; 1 spec, UMML 30-8260. Remarks - Cyomestis meekianus remains a very rare species, known only from the speci- mens cited above. The range of this species in- cludes the three BLAKE stations along the northwest coast of Cuba and the single PILLS- BURY station southwest of Jamaica. The PILLSBURY specimen is the largest known for this species, measuring 26.0 mm in length. Cyomesus chaunax (Bayer, 1971) Fig. 3 Teramachia chaunax Bayer, 1971: 198, figs. 54 (right), 55 R-C. - Rehder, 1972: 8. -Abbott, 1974: 243. Benthovoluta chayiuix: Cernohorsky, 1973: 127. Description -See Bayer, 1971. Holotype -USNM 701216. Length 28.1 mm; width 8.9 mm. Type-locality -RIY JOHN ELLIOTT PILLS- BURY sta. P-904, 13°45.5'N, 61°05.7'W, 201- 589 m. Material examine;/- PILLSBURY sta. P-904, 13°45.5'N, 61°05.7'W, 201-589 m; 1 spec, USNM 701216 (holotype).- COLUMBUS ISE- LIN stations in Tongue of the Ocean, Bahamas: CI-80, 23°54'N, 77°04'W, 1244 m; 1 spec, LTVIML 30-8261. -CI-79, 23°5rN, 76°51'W, 1289 m; 2 spec, UMML 30-8262. -CI-151, 23°52.2'N, 76°48.5'W, 1315 m; 1 spec, UMML 30-8263. -CI-363, 23°51.6'N, 76°51.9'W, 1324-1315 m; 1 spec, UMML 30-8264.- CI-156, 23°44.4'N, 76°48.3'W, 1334 m; 1 spec, UMML 30-8265. -CI-368, 23°43.2'N, 76°50.5'W, 1352-1342 m; 1 spec, UMML 30- 8266.-CI-252, 23°38.5'N, 76°47.8'W, 1322- 1332 m; 1 spec, UMML 30-8267. -CI-158, 23°30.7'N, 76°56.8'W, 1317 m; 1 spec, UMML 30-8268. -CI-14, 23°33'N, 77°09'W, 1246 m; 1 spec, UMML 30-8269. -CM63, 23°31.6'N, 77°08.3'W, 1342 m; 1 spec, UMML 30-8270.- CI-47, 23°42'N, 77°08'W, 1372 m; 1 spec, UMML 30-8271. -CI-54, 23°54'N, 77°13'W, 1298 m; 2 spec, UMML 30-8272. -CI-55, 23°57'N, 77°18'W, 1353 m; 1 spec, UMML 30-8273. -CI-303, 23°54.8'N, 77°18.4'W, 1390-1389 m; 2 spec, UMML 30-8274.- CI-365, 23°51.2'N, 77°16'W, 1372 m; 1 spec, UMML 30-8275. -CI-165, 24°04.7'N, 77°22.3'W, 1426 m; 1 spec, UMML 30-8285.- CI-406, 23°57.3'N, 77°20.8'W, 1408-1399 m; 1 spec, UMML 30-8286. Remarks -This, the most recently described species of Cycmiesus, is now the best known. The present material considerably extends the range of the species to the north and west. However, it is recorded from two areas, the Tongue of the Ocean, Bahamas, and St. Lucia, with no mate- rial from in between, although U.S. Government and University of Miami ships have made nu- merous collections within that area. Specimens of C. chaunax have not been discovered from any of the other Bahamian deep-water basins, although not all of the material collected from Exuma Sound has been sorted. The TOTO speci- mens of C. chaunax show that the species is rather conservative morphologically. Most of these specimens are somewhat more inflated than the type but not exceedingly so. One speci- men is 55 mm long, making C. chaunax the largest species of the genus. Cyomesus costatus (Dall, 1890) Fig. 2 Fasciolaria (Mesorhytis) costatun Dall, 1890: 317, pi. 5, fig. 5. Mesorhytis costattis: Cernohorsky, 1970: 52. -Rehder. 1972: 8. Teramachia costatus: Bayer. 1971: 197.-Abbott, 1974:243. Benthovoluta costata: Cernohorsky. 1973: 129. Description -See Dall, 1890. Holotype-\JSNM 96507. Length 13.8 mm; width 4.5 mm. Vol. 95(2) April 30, 1981 THE NAUTILUS 75 FIGS. 1-5. 1, Cyomesus meekianus (Dull. li;89). Lectotype, USNM 86970. 154 mm. 2, Cyomesus costatus (Dall, 18901- Holotype. USNM 96507. IS. 8 nun. 3, Cyomesus chaunax (Bayer. 1971). Holotype. USNM 701216. 28.1 mm. 4, Cyomesus aratiunculus sp. nov. Holotype, USNM 784594. 29.0 mm. 5, Cyomesus barthelowi (Bartsch. 191,2). Holotype. USNM238JM, 27.5 mm. Type-locality -ALBATROSS sta. 2751, 16°54'N, 63°12'W, 1256 m. Material examined-See Holotype (only known specimen). Remarks -Oi the four Caribbean species of Cyomesus, C. costatus is the most uncharac- teristic. However, its strongly convex whorls are similar to the early whorls of C. meekianus, and its other characteristics are so similar to the other Cyomesus species that I have little doubt C. costatus belongs in this group. Cyomesus aratiunculus sp. nov. Fig. 4 Description- Shell elongately fusiform, strong, coarsely sculptured. Apical whorls lost, 6V2 whorls remaining. Whorls with low, weak axial folds evident only from above to just below periphery, separated from each other by some- what wider interspaces. Numerous (41 on last whorl) irregular, crowded, unequal spiral threads covering whorls from suture to tip of anterior canal. Suture indistinct. Aperture nar- rowly lanceolate; outer lip simple; columella twisted to left anteriorly, with 3 oblique, lamelliform plicae, increasing in size from anterior to posterior; parietal wall without callus. Animal unknown. Holotype -VS'NM 784594. Length 29.0 mm; width 9.3 mm. Type-locality -RIV JOHN ELLIOTT PILLS- BURY sta. P-984, 18°26.4'N, 63°12.6'W, 430 m. Material examined-See Holotype (only known specimen). 76 THE NAUTILUS April 30, 1981 Vol. 95(2) Remarks -In general shape and size, Cyome- siis aratiunculus is extremely similar to C. chaunax and C. meekianus. The axial folds restricted to the periphery and the persistent spiral sculpture immediately distinguish C. ara- tiunculus from the other species. Cyomesus barthelowi (Bartsch, 1942) Fig. 5 Prodallia barthelowi Bartsch, 1942: 12, pi. 2, fig. 2. Teramachia barthelowi: Weaver and duPont, 1970: 177, pi. 75, figs. C, D.-Bayer, 1971: 196-198. "Teramachia" barthelowi: Rehder, 1972: 7. Benthovoluta barthelowi: Rehder, 1972: 8. -Cernohorsky, 1973: 127. Description- See Bartsch, 1942; Weaver and duPont, 1970. Holotype -US^M 238444. Length 27.5 mm; width 8.0 mm. Type-locality- ALBATROSS sta. 5425, off Cagayan Island, Sulu Sea, Philippines, 905 m. Material examined -See Holotype (only known specimen). Remarks -I am placing this species in Cyome- sus. However, the unique axial sculpture of deeply incised grooves, presence of two instead of three columellar plicae, and geographic isola- tion from the Caribbean species may indicate a need for a separate subgenus to accommodate C. barthelowi. Soft parts of C. barthelowi must be examined before a satisfactory solution can be reached. ACKNOWLEDGMENTS I am grateful to Dr. Joseph Rosewater of the USNM for his cooperation during my visits to the museum, for making photographs of some types, and loaning specimens without which this paper could not have been completed. I thank Mr. Fred Collier for loaning the syntypes of Mesorhytis gracilenta contained in the paleon- tological collections of the USNM. Dr. Gilbert L. Voss provided access to the collections of RSMAS, University of Miami. Some of the specimens contained within these collections were obtained during the University of Miami- Deep Sea Biology Program under the direction of Drs. Voss and F. M. Bayer. This paper con- stitutes Contribution 135 of that program. Cruises of R/V COLUMBUS ISELIN to the Tongue of the Ocean, Bahamas, were supported by National Science Foundation Grant OCE- 73-06639-A02, Dr. C. Richard Robins, Prin- cipal Investigator. W. G. Lyons and D. K. Camp kindly commented on this paper, and Sally D. Kaicher provided the photographs. LITERATURE CITED Abbott, R. T. 1974. American Seashells. 2nd Ed. Van Nostrand Reinhold Co., New York, 663 pp. Bartsch, P. 1942, Some deep-sea Philippine volutids. The Nautilus 56(1):9-13. Bayer, F. M. 1971. New and unusual mollusks collected by R/V JOHN ELLIOTT PILLSBURY and R/V GERDA in the tropical western Atlantic. Bull. Mar. Sci. 21(1): 111-236. Cernohorsky, W. 0. 1970. Systematics of the families Mitri- dae and Volutomitridae (Mollusca: Gastropoda). Bull. Auckl. Inst. Mus. 8:1-190. 1972. A taxonomic evaluation of recent and fos- sil non-mitrid species proposed in the family Mitridae (Gastropoda: Mollusca). Rec. Auckl. Inst. Mus. 9:125-194. . 1973. The taxonomy of Benthovoluta hilgendcrrfi (von Martens) and allied turbinellid genera (Mollusca: Volutacea). Rec. Auckl. Inst. Mus. 10:123-131. Conrad, T. A. 1855. Observations on the Eocene deposit of Jackson, Mississippi, with descriptions of thirty-four new species of shells and corals. Proc. Acad. Nat. Sci. Phila. 7(7):257-263. Da]l, W. H. 1889a. Reports on the Mollusca. Part II. Gastro- poda and Scaphopoda. Reports on the results of dredg- ing .. . in the Gulf of Mexico (1877-78) and the Caribbean Sea (1878-80), by the U.S. Coast Survey steamer "Blake" . . . Bull. Mus. Com.p. ZooL. Harv. 18:1-492. 1889b. A preliminary catalogue of the shell- bearing marine mollusks and brachiopods of the south- eastern coast of the United States. Bull. U. S. Natl. Mus. 37:1-221. 1890. Preliminary report on the collection of Mollusca and Brachiopoda obtained in 1887-88. Scientific results of explorations by the U.S. Fish Commission steamer "Albatross". No. VII. Proc. U. S. Natl. Mus. 12:219-362. 1908. The Mollusca and the Brachiopoda. Re- ports on the scientific results of the expedition to the eastern tropical Pacific ... by the U.S. Fish Commission steamer "Albatross" . . . Bull. Mus. Comp. ZooL, Han. 43:205-487. Habe, T. 1952. Pholadomyidae, Clavagellidae, Pandoridae, Juliidae and Condylocardiidae in Japan. In: T. Kuroda (ed.). Illustrated Catalogue of Japanese Shells, 1(18): 121-132. Johnson, C. W. 1934. List of marine Mollusca of the Atlan- tic coast from Labrador to Texas. Proc. Bo.^t. Sac. Nat. Hist. 40:1-204. Kuroda, T. 1931. Two new species of Volutacea. Venus 3(l):45-49. 1952. On an interesting new genus of gastropod Mollusca from the sea of Kii Peninsula. Publ. Seto Mar. Biol. Lab. 2(2):69-71. Vol. 95(2) April 30, 1981 THE NAUTILUS 77 1965. On the generic position of Benthovoluta (Gastropoda). Venus 24(l):50-.52. Kuroda, T. and T. Habe. 1950. Volutidae in Japan. In: T. Kuroda (ed.), lUustrated CntaUigue of Japanese Shells l(5):31-38. Meek, F. B. 1876. A report on the invertebrate Cretaceous and Tertiary fossils of the Upper Missouri Country. Rep. U. S. Geol. Sum. Ten: 9: Ixiv + 629. Norman, A. M. 1879. The Mollusca of the fjords near Ber- gen. Joum. Conchyl. 2:8-77. Rehder, H. A. 1967. A new genus and two new species in the families Volutidae and Turbinellidae (Mollusca: Gastro- poda) from the western Pacific. Par. Sci. 21(2):182-187. 1972. Some notes on the genus Teramachia (Volutidae: Calliotectinae). Velige.r 15(1):7-10. Sohl, N. F. 1963. New gastropod genera from the late Upper Cretaceous of the east Gulf Coastal Plain. Joum. Paleont, 37(4):747-757. Stimpson, W. 1865. On certain genera and families of zooph- agous gasteropods. Amer. Joum. Conch. 1:55-64. Swainson, W. 1840. A Treatise on Malacology: or the nat- ural classification of Shells and Shellfish. VIII. London, viii ■¥ 419 pp. Thiele, J. 1929. Handhiich der systematischen Weichtier- kunde. Teil 1. Gustav Fischer, Jena, pp. 1-376. Weaver, C. S. and J. E. duPont. 1970. Living volutes. A monograph of the Recent Volutidae of the World. Del. Mus. Nat. Hist., Monogr. 1: xv -H 375 pp. REMARKS ON MURICODRUPA IREDALE, 1918 (MURICIDAE: THAIDINAE), WITH THE DESCRIPTION OF A NEW SPECIES William K. Emerson American Museum of Natural History New York, New York 10024 and Anthony D'Attilio Natural History Museum San Diego, California 92112 ABSTRACT Muricodrupa jacobsoni, a new species known only from Melanesian populations (Bisynarck Archipelago, Solomon and Fiji Islands), is described and dedicated to the late M. K. Jacobson. Radular and opercular figures are provided for Muricodrupa fenestrata (Blainville, 1832). and M. funiculus (Wood, 1828). A lec- totype of Murex margariticola Broderip is selected and illustrated, and con- sidered to be a junior synonym of Cronia fiscella (Gmelin, 1 791). The classification of the numerous species- group taxa with Morula-like shell characters has long presented problems to students of murica- cean gastropods. The thaidid genus Morula Schumacher, 1817, remains a genus-group receptacle for numerous, small, non-spinose forms with denticulate apertures without regard for the limitations dictated by the characters of the type species, Drupa uva Roding, 1798 (cf. Radwin and D'Attilio, 1972). Recent investigations on the radulae of various moruloid species, including those of Arakawa, 1962, 1965; Cernohorsky, 1969; Emerson, 1968, Emerson and Cernohorsky, 1973; Radwin and D'Attilio, 1971, 1972; Wu, 1965, 1968, and others, have advanced the morphological know- ledge of these rachiglossate gastropods. The basic familial and subfamilial classification of the Muricacea, however, remains in a state of flux. Some workers largely ignore the radular characters and rely mostly on shell morphology for defining familial-level groups. Such is the case for the thaidid taxa. Some workers separate the Thaididae from the Muricidae, while others recognize subfamilial rank within the Muricidae for the thaidine taxa (see sum- mary by Cernohorksy, 1969, p. 293). The new species described below belongs to a small group of Indo-Pacific taxa characterized by shells possessing deeply pitted, squarish in- terspaces formed by the junction of the axial and spiral ribs. In the absence of knowledge on its radular morphology, the present species is tentatively referred to the genus Muricodrupa Iredale, 1918, for which the radular dentition of the type species is described and illustrated. We name this new species in the cherished memory of a longtime friend and valued col- 78 THE NAUTILUS April 30, 1981 Vol. 95(2) league, Morris Karl Jacobson (1906-1980), in recognition of his many and varied contributions to the field of malacology. Family Muricidae Rafinesque, 1815 Subfamily Thaidinae Suter, 1909 Genus Muricodrupa Iredale, 1918 Muricodrupa Iredale, 1918, p. .38; Thiele, 1929, p. 29.5; Wu, 1968, p. 90, radular drawings of "Muricodrupa elangata [sic] (Blainville)" pi. 4, figs. 4, 5. Type species by original designation: Purpura fenestrata Blainville, 1832, p. 221, pi. 10, fig. 11. Synonyms: Murex cariosus Wood, 1828, Suppl. p. 15, Murex pi. 5, fig. 22 [not Linne, 1767, p. 1220]; Purpura "alongee" [vernacular for elongata] Blainville, 1832, pi. 10, fig. 9, fig. only [nomen nudum]; Purpura cancellata Quoy and Gaimard, 1833, vol. 2, p. 563, atlas (2), pi. 37, figs. 15-16 [not Roding, 1798, p. 143]; Ricinula elongata Reeve, 1846, Ricinula no. 25, pi. 4, fig. 25. Radular characters of type species: Five cusps on the rachidian tooth, with central cusp narrow and long, lateral cusps about % the length of the central cusp, intermediate cusps small and lo- cated near the laterals (figs. 5a, 5c); lateral tooth large and normally hooked (fig. 5b). Opercular characters of type species: Outline broadly ungniculate, margin thickened on one side, central area depressed, with irregular rais- ed, concentric rings on the interior surface (fig. 7b). Muricodrupa jacobsoni, n. sp. Figs. 1-4 Description - Shell moderately large for genus, attaining 35* mm in height, low spired; nature of protoconch unknown (eroded off speci- mens); suture weakly defined and interrupted by varical buttresses; whorls 4*, weakly convex, shouldered, spire short, blunt. Aperture narrow- ly ovate, inner lip mostly adherent, outer lip finely fluted, ornamented with 6 well-defined, evenly spaced denticles, set slightly back from apertural margin, with the lowest denticle above the entrance to canal and the uppermost denticle below the shoulder area; anal trough with a prolonged sinus extending above the shoulder, delineated within on the left side by a minor denticle and on the right side by a swollen and more prominent denticle isolated above the 6 lower denticles; canal, broad, mostly open, tapering and recurved distally, siphonal fasciole coarsely sculptured with previous canal termin- ations; pseudo-umbilical pit present. Sculpture consisting of 6 varices with visibly defined varical margins, rounded with equal or wider in- terspaces, varices crossing the angulate shoulder slightly oblique and forming buttresses against the previous whorl; shoulder deeply ex- cavated in the interspaces; varices with low, scabrous lamellae on varical leading surface; number of costae increasing by one or two on the spire; 3 primary spiral cords situated on the body, along with an occasional secondary cord; a major cord in concave area below the body; canal with one major cord, supplemented with minor or secondary cords; spiral sculpture crossed by lamellose growth striae, scabrously ornamented where not abraded. Shell color - matte white, apertural interior white in holotype, tinged with pale violet in paratypes. Type-locality - Astrolabe Barrier Reef, Yanu- yanu-i-lona Island, Fiji Islands (19°55'S, 178°35'E), Kauter and Williamson, 1971. Holotype from type locality, LACMNH no. 71-205; measurements 35.5 mm in height, 16.9 mm in width; fig. 1. Other material examined: Paratype A, fig. 2, AMNH 201460 (ex-Tulane University, Department of Geology), Manus Island, Bismarck Archipelago; 31.5 mm in height, 16.8 mm in width. Paratype B, fig. 3, SDNHM Type No. 76523, Nudha Island, Solo- mon Islands, American Mela Expedition Station 18; 38.5 mm in height, 20.2 mm in width. Para- type C, Billee Mabry, June-July, 1978, Billee Mabry Collection, same locality as for Paratype B; 37.2 mm in height, 17.9 mm in width. Para- types D and E, Guadalcanal, Solomon Islands; paratype D, 36.3 mm in height, 17.1 mm in width; paratype E, fig. 4, 37.8 mm in height, 13.4 mm in width, Thora Whitehead Collection. DISCUSSION The new species, together with its species- group congeners, is characterized by the promi- nent cavernous excavations between the varical Vol. 95(2) April 30, 1981 THE NAUTILUS 79 FIGS. 1-4. Muricodrupa jacobsoni, n. sp.. all x IV2. 1, hutotype, Yanu-yanu-i-loma Island, Fiji Islands, LACMNH 71-205. 2, paratype A. Manus Island, Bisma7xk Archipelago, AMNH 20H60. 3, paratype B. Nudha Island, Solomon Islands. Billee Mabry Collection. 4, paratype E, Rove, Guadalcanal Island, Solomon Islands, Thora Whitehead Collection. and spiral ridges, which form squarish pits. It is readily distinguished from its closest relatives by the extended narrow form of the shell, the blunt spire and broad canal. The new species has been confused with Mur- icodrupa funiculiis (Wood, 1828, p. 15, Murex pi. 5, fig. 17), locality unknown; radula and oper- culum here illustrated, figs. 6a, b; 8a, b. We con- sider Muricodrupa decussata (Reeve, 1845, Murex species 153, pi. 31, fig. 153), "Island of Bohol, Philippines," type specimens not located in the BM(NH) teste J. H. McLean and Murico- drupa triangulata (Pease, 1868, p. 278, pi. "233", fig. 15, "Insl. Hawaii") to be junior synonyms of Muricodrupa funiculus (Wood, 1828). Compared to the new species. Wood's taxon has an essentially triangular form, is broad at the shoulder relative to height, has a more spinose shoulder carina, and has three denticles anteriorly positioned on the columella. 80 THE NAUTILUS April 30, 1981 Vol. 95(2) FIGS. 5a-5c. Radular dentition of Muricodrupa fenestrata (Blaimnlle), greatly enlarged; SW Rarotonga Island. Cook Islands, ANSP 278974. 6a-6b, Radular dentition of Muricodrupa funiculus (Wood), greatly enlarged; Rodda Reef Queensland. Australia, SDSNH 51212. Kay (1979, p. 238, fig. 831) assigned Murico- drupa triangulata (Pease) to the synonymy of Muricodrupa funiculus (Wood). Cernohorsky (1969, p. 311, pi. 49, fig. 25), however, referred Pease's taxon to the synonymy of Morula (Crania) fiscella{Gme\m, 1791, p. 3552, no. 160), but his figured specimen represents an example of Muricodrupa funiculus (Wood). Cerno- horsky's nomenclatural interpretation of the identity of Murexfiscellum Gmelin was based on the figure citations by Gmelin (1791, p. 3552) to Chemnitz's (1788, vol. 10, pi. 160, figs. 1524, 1525) illustrations and on the descriptive text. Chemnitz's text (op. cit., p. 242) describes the shell as being "... strongly clathrate with deeply recessed windows (depressions) which are col- oured brown", and Cernohorsky (1969, p. 311) concluded that the ". . . description and figure [sic] are only applicable to M. fiscella not to M. margariticola." The figures of Chemnitz, how- ever, lack squarish windows, whereas the col- oration and sculpture are much closer to Morula margariticola (Broderip, 1833, p. 177), as figured by Cernohorsky (1969, p. 312, pi. 49, fig. 26, and 1972, pi. 128, pi. 36, fig. 8). Cernohorsky (1978, p. 69, pi. 20, fig. 5) illustrates what ap- pears to be a specimen of Morula margariticola (Broderip, 1833) (our concept oi fiscella Gmelin) under the name (Cronia crassulnata (Hedley, 1915), and he (1978, p. 70, pi. 20, fig. 6) il- lustrates a specimen of Muricodrupa funiculus (Wood, 1828) as Cronia triangulata (Pease, 1868), which he suggests may prove to be an ex- treme form of Cronia fiscella (Gmelin, 1791). FIGS. 7a- 7b. Opercular characters (7a. outer surface; 7b, in- ner surface) of Muricodrupa fenestrata (Blaimnlle), greatly enlarged; Truk Lagoon, Moen Island, Caroline Islands, SDSNH 7652J,. 8a-8b, Opercular characters (8a. outer sur- ftwe; 8b inner surface) of Muricodrupa funiculus (Wood), greatly enlarged; Palmyra Island, Line Islands, SDSNH ni88. Vol. 95(2) April 30, 1981 THE NAUTILUS 81 It is our view that Murex fiscellum (Gmelin, 1791) should be based on the drawings of Chem- nitz (op. cit.), which lack any indication of squarish, window-like depressions, and, in the absence of the type specimens, should represent the typological concept of Gmelin's species. Moreover, the descriptive text of Chemnitz (op. cit.) could reasonably be applied to several other moruloid species with squarish pits, such as the type species of Muricodrupa, Purpura fene- strata Blainville, 1832. Therefore, we interpret Murex fiscellum Gmelin to be referable on the basis of Chemnitz's illustrations (op. cit.) to the common and wide-ranging Indo-Pacific species subsequently described as Murex margariticola Broderip, 1833, p. 177; Reeve, 1846, Murex species 178, pi. 34, fig. 178; syntype here il- lustrated, fig. 9. This interpretation agrees with the concept of Murex fiscellum Gmelin arrived at by Lamarck (1822, p. 346), Blainville (1832, p. 206', pi. 10, fig. 8), and Reeve (1846, Ricinula sp. 28, pi. 4, fig. 28), who would qualify as the First Revisor under Article 24 of the International Code of Zoological Nomenclature of the International Congress of Zoology. In summary, Muricodrupa jacobsoni, n. sp. is most closely related to M. funiculus (Wood, 1828), [synonyms: Murex decussatus Reeve (1845, Murex species 153, pi. 31, fig. 153); Pur- pura stellaris Hombron and Jacquinot (1853, atlas, pi. 22, figs. 13, 14); Coralliophila con- FIG. 9, Murex margariticola BrodeWp, one of three syntypes in The British Museum (Natural History), x I'k; this specimen is selected as the lectotype. It is a junior synonym u/Cronia iisceWa (Gmelin. 1791). fragosa H. and A. Adams (1864, p. 432), and Sistrum triangulatum Pease (1868, p. 278, pi. 23, fig. 15)]. Whereas Cronia fiscella (Gmelin, 1791), [synonyms: Murex margariticola Brode- rip (1833, p. 177), Purpura thiarella Quoy and Gaimard (1833, p. 571, pi. 39, figs. 4-6) [not Lamarck, 1822, p. 246], [?] Thais crassulnata Hedley (1915, p. 749, pi. 85, fig. 90), and Morula rhyssa Dall (1923, p. 304, a new name for Ricinula fiscella Reeve, 1846)], with which the new species also has been confused, is a distinc- tive species. The type species of the genus-group taxon Cronia H. and A. Adams, 1853, Purpura amygdala. Kiener (1835), apparently has radular morphology (Cooke, 1919, fig. 33) similar to that of the type species of Muricodrupa. ACKNOWLEDGMENTS We are indebted to the following friends and colleagues for kindly providing specimens for study: Billee Mabry, Richard Salisbury, Thora Whitehead, Emily H. Yokes (Tulane Univer- sity), Virginia Orr Maes (Academy of Natural Sciences of Philadelphia), and James H. McLean (Los Angeles County Museum of Natural His- tory), who also photographed typological specimens in the British Museum (Natural History). The remaining photographs were taken by Sidney S. Horenstein. William E. Old, Jr., contributed technical assistance. LITERATURE CITED Adams, H. and A. Adams. 1853-1854. The genera of Re- cent Mollusca. arranged according to their organization. London, vol. 1, p. xi + 256 [1853], p. 257-484 [1854]. 1864. Descriptions of new shells chiefly from the Cumingian collection. Proc. Zool. Soc. London, pp. 428- 438. (Apr., 1864). Arakawa, K. Y. 1962. A study on the radulae of the Japa- nese Muricidae. The genera Purpura, Thais, and Manci- nella. Venus 22(l):70-78. 1965. A study on the radulae of the Japanese Muricidae. The genera Drupa, Drupina. Drupella, Cro- nia, Morula, Morulina, Phry(fiomurex. Cyniia, and Ten- guella gen. nov. Ibid. 24(2):113-126. Blainville, H. M. D. de, 1832. Disposition methodique des especes recentes et fossiles des genres Pourpre, Ricinule, Licorne et Concholepas de M. de Lamarck. Nouv. Ann. Mus. Nat., Paris 1:189-263. Broderip, W. J. In, Broderip, W. J. and G. B. Sowerby, L, 1833. Characters of new species of Mollusca and Conchi- fera, collected by Mr. Cuming. Proc. Zool. Soc. London, pp. 173-179. (Jan. 14, 1833). 82 THE NAUTILUS April 30, 1981 Vol. 95(2) Chemnitz, J. H. 1788. Neues syst.ematisch£s Conchylien- Cabinet (continuation of F. H. W. Martini) Niirnberg, vol. 10, xxiv + 376 p. Cernohorsky, W. 0. 1969. The Muricidae of Fiji, Pt. 2, Sub- family Thaidinae. Veliger 11(4):293-315. Cernohorsky, W. J. 1972. Marine shells of the Paeific. Syd- ney, vol. 2, 411 p. Cernohorsky, W. 0. 1978. Tropical Pacific marinie shells. Sydney, vol. 3, 352 p. Cooke, A. H. 1919. The radula in Thais, Drupa, Morula. Concholepax. Cronia. lopas. and the allied genera. Proc. Malacol. Soc. London 13(3 & 4):90-110. Dall, W. H. 1923. Notes on Drupa and Morula. Proc. Acad. Nat. Sci. Philadelphia 75:303-306. Emerson, W. K. 1968. Azumanwrula, new name for Moru- lina Dall, 1923, not Boerner, 1906. Th£ Nautilus 81(4): 125-127. Emerson, W. K. and W. 0. Cernohorsky. 1973. The genus Drupa in the Indo-Pacific. Indo-Pacific Mollusca 3(13): 1-40. Gmelin, J. F. 1791. Systermi naturae per regno tria nature . . .. ed. 13. Leipzig 1(6):3021-3910. Hedley, C. H. 1915. Studies on Australian Mollusca. Pt. 12, Proc. Linn. Soc. New South Wales 39(4):695-755 (Feb. 26, 1915). Hombron, J. B. and C. H. Jacquinot, Zoologie, vol. 5. De- scription des mollusques, . . ., In, Rousseau, L., 1842- 1853 [pis.], 1854 [text]. Voyage au Pole Sud et dans rOceanie sur les corvetts I'Astrolabe et la Zelee, execute . . . pendant . . . 1837-1840. Iredale, T. 1918. Molluscan nomenclatural problems and solutions. No. 1 Proc. Malacol. Soc. London 13(1&2): 28-40. Kay, E. A. 1979. Hawaiian marine shells. Reef and shore fauna of Hawaii, Sec. 4: Mollusca. B. P. Bishop Mus., Honolulu, xvii + 653 p. Kiener, L. C. 1835. Species general et icotiographie des coquilles vivantes. Genre Pourpre. Paris, vol. 8, pp. 1-151. Lamarck, J. B. P. A. de M. de. 1822. Histoire naturelle des animaxix sans vertebres. Paris, vol. 7, 711 p. Linne, Carl von, 1767. Systema naturae per regna tria naturae . . ., ed. 12. Stockholm, [Regnum animale], 1(2): 533-1327. Pease, W. H. 1868. Descriptions of sixty-five new species of marine gasteropodae. inhabiting Polynesia. Avier. Jour. Conch. 3(4):271-297, [April 2, 1868]. Quoy, J. R. C. and J. P. Gaimard, [1832-] 1833 [-1835]. Voy- age d£ decouvertes de rAstrolabe. execute par ordre du Roi Paris. Zoologie, Mollusca 2:321-686 (1833), atlas (1835). Radwin, G. E. and A. D'Attilio, 1971. Muricacean supra- specific taxonomy based on the shell and radula. Echo, Western Soc. Malacologists 4:55-67. 1972. The systematics of some New World muricid species . . . with description of two new genera and two new species. Proc. Biol. Soc. Wash. 85(28): 323-352. Schumacher, C. F. 1817. Essai d'un nouveau systeme des habitations des vers testaces. Copenhagen, iv ■¥ 287 p. Reeve, L. A. 1845-1846. Conchologia iconica. London, vol. 3, Monograph of the genus Murex, text with 36 pis. 1846. Conchologia ieonica. London, vol. 3, Mono- graph of the genus Ricinula, text with 6 pis. Roding, P. F. 1798. Museum Boltenianum . . . pars secunda continens Conchylia. Hamburg, vii -i- 199 p. Thiele, J. 1929. Handhuch der systematischen Wekhtier- kunde. Jena, l(l):l-376. Wood, W. 1828. Supplement to the Index testcuxologicus; or a catalogue of shells, British and foreign. London, vi + 59 p. Wu, Shi-Kuei, 1965. Studies of the radulae of Taiwan muri- cid gastropods. Bull. Inst. Zool, Acad. Sinica 4:95-106. 1968. On some radulae of the muricid gastro- pods. Venus 27(3):89-94. NEW RECORDS OF LAND MOLLUSCA IN NEW YORK CITY Bruce Einsohn Department of Physical Sciences Kingsborough Community College Brooklyn, NY 11235 Cecilioides acicula (Miiller), a small achatinid snail, has been found in Inwood Hill Park at the extreme northern end of Manhattan Island in New York City. This is the first reported occur- rence of this species in New York State. Specimens of C. acicula were discovered along a rocky ridge where the snails were found attached to the undersides of bricks from the ruins of what appears to have been a green- house. At this site nine species of shelled pul- monates, in addition to the Cecilioides, were found within a few square feet: Cochlicopa lubrica (Miiller), Eitx;onulus fulvus (Miiller), Hawaiia minuscula (Binney), Helicodiscus parallelus (Say), Oxychilus cellarius (Miiller), 0. draparnaldi (Beck), Pupoides albilabris Vol. 95(2) April 30, 1981 THE NAUTILUS 83 Adams), Vallonia pulchella (Miiller), and Ver- 'igo cf. veyitri.cosa (Morse). Several species of slugs have also been recorded. Curiously, Zo7ii- 'aides arboreiis (Say), moderately common else- tvhere in the park, has not been found here. Vallonia costata (Miiller) was also found in In- A^ood Hill Park, as well as at other locations in northern Manhattan. These occurrences consti- ;ute the first record of this species for Manhat- jan (New York County), but not for New York [lity. V. costata was not recorded from the New York Metropolitan Area until some 20 years ago A'hen Jacobson and Emerson (1961) reported it Tom Van Cortlandt Park in the Bronx, but that colony evidently does not exist today. I carefully searched the environs of Van Cortlandt Park A'ithout finding V. costata. In the New York ^hell Club Notes for May, 1962 (no. 82) H. S. Peinberg reported V. costata from the Riverdale section of the Bronx. I was able to confirm this 'ecord at a site some two miles southwest of V^an Cortlandt Park in November, 1977. Subse- quently, I was able to establish the Manhattan records. V. costata is found under stones and fallen logs, and in rock crevices. It occurs in close association with V. pulchella. The animals of the two species appear quite similar in their gross aspects, both being white with con- spicuous black eye spots. Specimens of Cecilioides acicula and Vallonia costata, both from Inwood Hill Park, have been deposited in the American Museum of Natural History (catalog numbers 200375 and 201470 respectively). I would like to gratefully acknowledge the assistance of the late M. K. Jacobson who read portions of this manuscript and made helpful criticisms. It was he who first suggested that Cecilioides might be the correct genus for what proved to be C. acicula. I would also like to thank William E. Old, Jr. of the American Mu- seum who granted me access to the Museum's collections and library. LITERATURE CITED Jacobson, M. K. and W. K. Emerson. 1961. Shells of the New York City Area. Argonaut Books. Larchmont, N.Y. 142 p. CORBICULA FLUMINEA, IN LAKE ERIE Arthur H. Clarke Ecosearch, Inc. 7 Hawthorn Street Mattapoisett, MA 02739 On December 17, 1980, 2 living juvenile speci- mens of Corbicula fluminea (Miiller) were col- ected in the western end of Lake Erie at Mon- roe, Monroe County, Michigan, by me and by two divers, Messrs. Al Melkic and Ted Creese, rhis is the first record of C. fluminea from the jreat Lakes-St. Lawrence drainage system, rhe specimens both occurred on a sand bottom in 3 feet of water at Sterling State Park, one off- shore from a point 1000 feet south of the south- ern end of a rocky dike near the mouth of Sandy 3reek and the other offshore from a point 2000 feet south of the same landmark. The lake level ivas 2.4 feet above mean low water (MLW) and the specimens were each found while screening the substrate from SM^ bottom samples through a V4-inch mesh screen. No other mollusks were found in these samples. The specimens were 8.0 and 8.6 mm long, respectively. C. fluminea probably cannot survive at such shallow depths in Lake Erie because of winter freezing and ice-scouring, but other juveniles from the same 1980 larval settlement probably occur nearby in deeper water. If water temper- atures permit, C. fluminea will probably now become widespread in the region. One suspects that the abundant bottom-feed- ing fishes in Lake Erie will keep C. fluminea 84 THE NAUTILUS April 30, 1981 Vol. 95(2) populations in the lake itself from becoming too populous and from exerting an adverse effect on native unionid populations. (Where dense pop- ulations of C. fluminea occur native unionids become rare, perhaps because the filter-feeding activities of C. fluminea remove unionid sperm from the water and interfere with unionid repro- duction). The eventual damage that C. flumiyiea will cause to water intake systems and other commercial activities in the region, however, may be significant. LIFE CYCLE OF THE FRESHWATER SNAIL CAMPELOMA DECISUM (VIVIPARIDAE) IN THE LABORATORY Marc J. Imlay^ John W. Arthur^, Barbara J. Halligan" and John H. Steinmetz' ABSTRACT Campeloma decisum reared in Minnesota Lake Superior water grew con- sistently well when clam meat or commercial fish food wees provided and a substrate of sand or mud was present. Food alone, or the substrate alone, was generally ineffective in promoting growth. Thick substrates were more effective than thin substrates. Substrate depth wa^ directly correlated with growth, although some growth occurred when no soft substrate was present. Campeloma decisum tested in Missouri hard well water grew equally well with or without a substrate. A population of newborn snails from the St. Croix River, Wisconsin was reared through three generations in U2 months on a diet of clam meat and trout chow with St. Croix River mud substrate. Survival of the original snails to Jfl months was 80%. Campeloma is an exclusively North American genus of ovoviviparus snails widely distributed in lakes and streams of eastern North America. Campelojna decisum (Say, 1819) plays an impor- tant role in the fish (Price, 1957) and diving duck (Thompson, 1973) food chains and has been used in studying the effects of toxicants in the labora- tory (Arthur, 1970, Arthur and Leonard, 1970). Arthur and Leonard (1970) studied the effects of a range of copper concentrations on survival, feeding and parturition of young Campeloma decisum snails. The snails completely devoured 'Columbia National Fisheries Research Laboratory U.S. Fish and Wildlife Service Route #1; Columbia, MO 65201 ^Environmental Research Laboratory U.S. Environmental Protection Agency Duluth, MN 55804 fresh unionid clam meat in copper concentra- tions of control (2.0 jig/l) up to 8.0 /jg/1 but would not accept or consume this food at the higher concentrations tested. Although the control snails fed at the rate of one clam per 10 snails per week, there was no measurable growth in 6 weeks. Thus, it was not possible to assess the ef- fects of copper on the ability of the snails to grow and complete the life-cycle. It was believed that experiments to determine why the snails fed without growing would demonstrate a way to grow the snails in the laboratory. A literature review suggested several expla- nations for why the snails fed without growing. The following describes several experiments which tested these ideas and ultimately culmi- nated in rearing Campeloma decisum through several generations in the laboratory. Allison (1942) trapped Campeloma with dead Vol. 95(2) April 30, 1981 THE NAUTILUS 85 fish or cloth packets of dog, cat, chicken, ferret or muskrat dung. Snails came from both up and down stream, with a maximum number of snails at the trap on the 10th day. Bovbjerg (1952) found populations of Campeloma decisum just downstream from rapids in the presence of silt and detritus. In the absence of factors that would orient the snails to food, the snails moved upstream (positive rheotactic response) but the hard surfaces associated with riffles or rapids blocked further upstream movement. Snails moving upstream did not travel over exposed surfaces of rocks. Snails also aggregated on the downstream side of log barriers or boulders. Thus, the literature reports that Campeloma decisum. feeds on decayed animal material and cannot function properly on a bare hard surface. In the following experiments Campeloma deci- sum was fed dead clams or other foods under various conditions of hard, sandy, muddy or other substrates. Water quality was also varied to determine the significance of hardness, cal- cium, or other minerals in growth. MATERIALS AND METHODS Effect of Substrate and Food Source In a study to determine if a soft substrate is needed for growth of snails, young Campeloma decisum and various substrates were collected from the St. Croix River, Douglas Co., Wiscon- sin where the calcium content was 32-37 mg/1 as CaCOs. Tests were run for 90 days in flowing carbon filtered water pumped from Lake Supe- rior at Duluth. During the tests, calcium was 46-53 mg/1 as CaCOs, temperature 18±1C, dissolved oxygen 8.2-10.2 mg/1, and pH 7.5-8.0. Ten or 20 snails as available were randomized by size and added to each of 48 10-liter tanks. Substrates provided were either mud or sand, 3.5-4.5 cm deep. Other snails were held in tanks with only glass substrates. Either one 10-15 cm long freshly killed unionid clam or 0.5 gram trout chow (Glencoe starter granules) was pro- vided every 1-2 weeks. Shell lengths were measured with vernier calipers (0.1 mm ac- curacy). Tests with Missouri Snails in Hard Water To determine further if a soft substrate was needed for growth of snails tested in hard water, young Campeloma decisum were col- lected from a muddy substrate in the Gasconade River, Osage Co., Missouri. Sandy substrate (with some silt and gravel in- termixed) was collected from a Gasconade tribu- tary and a layer of this substrate 2.3 cm thick was added to four aquaria each containing 10 snails and 10.3 liters of Columbia, Missouri hard well water (Ca, 70; Mg, 27; K, 3.9; SO4, 4.4; CI, 29; EDTA hardness, 272 mg/1). The water was continuously exchanged at the rate of 0.50-0.52 liters every 4-8 minutes. Four additional control aquaria differed in that no substrate was added to the glass bottom. One dead 10-12 cm freshwater mussel was fed every 3 weeks to the snails in each of two substrate and two control aquaria. This experiment ran from June 19-September 9, 1978 at 18.5-19. 3C. Campeloma Life Cycle Adult snails were collected in February, 1970 from the St. Croix River, Douglas Co., Wiscon- sin and placed on a sieved mud substrate in an aquarium at the Duluth Environmental Re- search laboratory. In August 1970, 30 newborn snails were recovered from this aquarium and placed in an aquarium with sieved mud sub- strate 3.5-4.5 cm thick. They were fed trout chow with clam meat ad libitum. The snails were provided with flowing Lake Superior water at 18±1C. The mud substrate was exchanged in March 1971, June 1973, and January 1974. Growth rates of the young snails were measured periodically. RESULTS Campeloma decisum tested in Duluth, Minne- sota soft water grew consistently well when clam or fish food was provided and a substrate of sand or mud was present (Table 1). For exam- ple, in one tank with glass substrate and clam meat growth was 0.3 mm (standard error of only 0.09) in 90 days. With mud substrate and clam meat the least growth was 0.8 mm. Food alone, or the substrate alone was generally ineffective in promoting growth. The most growth with mud alone was 0.7 mm. Thick substrates were more effective than thin substrates (Table 2). It 86 THE NAUTILUS April 30, 1981 Vol. 95(2) TABLE 1. Growth in 90 days o/Campeloma decisum snails (10-20 mm original lervgth) in varied substrates and food sources. Duluth soft water. Each number (except overall average) is average growth (mm) of 10 or 20 snails. Substrate provided None FOOD SOURCES Clam S- FUh Food Glass 0.0 0.0 0.0 0.1 O.I 0.2 0.3 0.09 0.4 o.e 0.8 1.0 1.2 0.4 0.05 0.8 0.25 0.9 0.12 1.0 0.25 1.0 0.19 1.1 0.28 1.3 0.33 1.3 0.31 1.3 0.15 0.1 0.2 0.2 0.2 0.7 0.8 1.0 2.0 "triT Mud 0.0 0.0 (St. Croix River) 0.0 0.1 0.1 0.1 ~ 0.1 0.2 0.2 0.3 0.7 0.16 Sand 0.1 0.1 (St. Croix River) 0.0 1.1 0.079 2.1 injT 0.7 0.17 0.7 0.22 0.9 0.23 1.0 0.21 1.3 0.33 0.9 0.10 TABLE 2. Growth in 90 days o/Campeloma decisum snails (10-20 mm original length) in varied St. Croix River mud substrate depths and food sources. Duluth soft water. Each number is average growth (mm) of 10 snails. Substrate provided Clam FOOD SOURCE S- Flsh Food Glass 0.0 0.0 0.0 o.s 0.5 0.7 0.098 1.5 1.1 1.1 ~r2i 0.10 1.0 nm 0.0 0.0 0.0 1.2 1.5 1.1 0.11 2.8 1.5 1.8 0.17 5.0 1 0.0 0.0 0.0 1.8 1.3 1.4 0.15 3.3 3.4 3.2 0.26 25.0 mi 0.0 0.0 0.0 2.1 2.2 2.5 t:7t 0.17 3.2 3.7 2.6 "TIT 0.17 Vol. 95(2) April 30, 1981 THE NAUTILUS TABLE 3. Growth of young Missouri snails June Q-Septetnber 19. Mi-ssouri hard water. 18.5-19.3C. 87 Substrate Food Initial No. Initial length im growth 102 days Final No. Alive Sand Glass Glass Sand clam 10 10.4 - 12.9 0.0 10 10 13.2 - 15.8 0.0 10 10 8.7 - 12.0 0.0 10 10 12.8 - 15.0 0.0 10 10 9.7 - 12.9 2.0 0.34 10 10 13.7 - 16.0 2.3 0.38 9 20 9.8 - 16.2 2.4 0.27 12 TABLE 4. Meayi length and number of survivors for several generations o/Campeloma decisum. The first getierntion produced at least three second generations. The first of these in turn produced a third generation. First Generation Second Generation Second Generation Second Generation Third Generation N Age length N Age length N Age length N Age length N Age length (months) (ran) (months) (mm) (months) (fim) (months) (mm) (months) (ran) August 1970 30 0 newborn January 1972 29 17 18.3 27 0 3.5 January 1973 28 29 23.1 March 1973 21 14 10.9 September 1973 27 37 23.7 14 20 17.4 30 6 January 1974 24 41 24.4 15 24 18.8 30 10 February 1974 June 1974 17 46 25.1 15 29 20.9 30 15 9.0 30 3 4.9 34 0 3.5 7.0 10 4 4.5 is seen that substrate depth was directly cor- related with growth, although some growth oc- ;nirred without any soft substrate. The survival rate was 80-100% per tank. Campeloma decisum tested in Columbia, Missouri hard water grew equally well with or without substrate (Table 3). A population of newborn snails from the St. Croix River, Wisconsin was reared through three genera- tions in 42 months on a diet of clam meat and trout chow with St. Croix River mud substrate [Table 4). DISCUSSION The demonstrated synergistic action of food and natural sand or mud substrate on growth of Campeloma decisum in the laboratory is prob- ably related to the preference of this species for sand or mud substrate in the wild. Further experimentation is required to deter- mine if the synergistic property of the substrate was a mineral such as calcium, a vitamin, sand grain digestive aid, protection from harmful wavelengths of light, or a "psychological re- quirement." It is not known if the lack of synergistic action of soft substrate and food for Missouri snails in Missouri hard water was due to calcium in the hard water or genetic dif- ferences from the Wisconsin snail population. Chamberlain (1958) cultured 45 North Carolina 88 THE NAUTILUS April 30, 1981 Vol. 95(2) Campeloma decisum "in isolation" in 4.5 inch fingerbowls containing a natural substrate of clayey silt with some sand and decaying organic debris. They grew at about the same rate as in nature but only two snails were still alive after 12 months. He found that Campeloma decisum from University Lake, Chapel Hill, North Carolina were not gravid before two years of age and until reaching 15.0 mm in length. The largest snail he collected was 27.3 mm long. The second year class lost identity as a size class at 20 mm in length. The parturition period was from mid-March until the end of June. Medcof (1940) who studied Campeloma deci- sum from the Speed River, Ontario, also re- ported that sexual maturity was reached in two years, and one, two, and three year old snails were 12, 17 and 23 mm long, respectively. The parturition period was from March- September. From Table 4 it may be noted that newborn snails (August 1970) reproduced in less than two years (January 1972, about 17 months after birth) presumably due to early parturition in the laboratory. The approximate maximum length (25.1 mm) obtained by snails in our study was similar to that found by Medcof (23 mm) and Chamberlain (20-27.3 mm). ACKNOWLEDGMENTS Dr. Henry van der Schalie, University of Michigan Museum and department of Zoology, and Dr. Carol B. Stein, Ohio State University Museum of Zoology, identified Campeloma decisum from Wisconsin and Missouri, respec- tively. Virginia Vail reviewed the manuscript. LITERATURE CITED Allison, L. N. 1942. Trapping snails of the genus Campelo- ma. Sftertrp 95:131-132. Arthur, J. W. 1970. Chronic effects of linear alkylate sul- fonate detergent on Gammarus pseudolimnaeus. Campe- loma decisum and Physa Integra. Water Research 4: 251-257. Arthur, J. W. and E. N. Leonard. 1970 Effects of copper on Gammarus pseudolimnaeus. Physa Integra, and Campelo- ma decisum in soft water. Journal Fisheries Research Board of Canada 27:1277-1283. Bovbjerg, R. V. 1952. Ecological aspects of dispersal of the snail Campeloma decwum. Ecology 33:169-176. Chamberlain, N. A. 1958. Life history studies oi Campeloma decisum. The Nautilus 72:22-29. Medcof, J. C. 1940. On the life cycle and other aspects of the snail, Campeloma. in the Speed River. Canadian Journal of Research 18(sec. D):165-172. Price, J. H. 1957. A study of the food habits of some Lake Erie fish, U.S. Fish and Wildlife Sennce Report No. 837, 105 pp. Thompson, D. 1973. Feeding ecology of diving ducks on Keokuk Pool, Mississippi River. Journal of Wildlife Man- agement 37:367-381. NEWS Dr. Arthur E. Bogan joined the staff of the Department of Malacology, Academy of Natural Sciences of Philadelphia in September 1980. He came to the Academy having received his doc- torate from the University of Tennessee, Knox- ville. His thesis was concerned, in part, with Unionidae in archaeology. His position, cura- torial associate, involves management of the growing computerized collection data base, generating reports from the data base such as: Catalog of the Chitm Types (1979; Tryonia, 1:1-60), identification of species, curatorial up- dating of families, processing new collections for cataloging. Dr. Bogan joins Drs. Davis and Robertson in managing the neontological and paleontological sections of the Department of Malacology. The collections are supported, in part, by a continuing grant from the National Science Foundation. The Western Society of Malacologists will hold its 14th annual meeting June 23-26, 1981, at the San Diego State University. The Ameri- can Malacological Union will hold its 50th an- niversary meeting July 19-24, 1981, in Ft. Lauderdale, Florida (details Jan. issue of The Nautilus, p. 37). The 1981 convention of the Conchologists of America will meet in San Francisco, California Sept. 2-5 at the Miyako Hotel in the Japan Center. Vol. 95(2) April 30, 1981 THE NAUTILUS 89 THE NORTHERN EXTENSION OF THE RANGE OF ANODONTA SUBORBICULATA SAY (BIVALVIA: UNIONIDAE) Marian E. Havlik Malacological Consultants La Crosse, Wisconsin 54601 ABSTRACT The naiad mollusk, Anodonta suborbiculata Say, 1831, has apparently never been reported alive m the Mississippi River main stem north ofFairport Iowa (River Mik 463). During 1977 two live specimens were collected m Bluff Slough at La Crosse, Wisconsin. Because of the obvious age difference in these specimens reproduction m the area seems likely. Three other living naiad species and four dead naiad species were also collected from this site The naiad mollusk Anodoyita suborbiculata Say, 1831, popularly known as the Heel-Splitter or Flat Floater, has apparently never been reported alive from the Mississippi River main stem above Fairport, Iowa (River Mile 463) (Coker, 1919), nor in the Illinois River north of Peoria Lake (Danglade, 1914). Witter (1883), in reporting on the mollusca of Muscatine County (Iowa), stated that A. subor- biculata was "common or even abundant, in Keokuk Lake, and lakes along Cedar (River), especially the lake on the west bank of Cedar, a half-mile below Moscow" (Iowa). Studies of the Mississippi River since the 1920's have not reported this species (Dr. M. M. Ellis (summariz- ed by van der Schalie and van der Schalie, 1950), Dawley (1947), Coon et al. (1977), Havlik and Stansbery (1978), Fuller (1978), Perry (1979) and Havlik and Marking (1981)). Apparently A. suborbiculata was never found in Wisconsin (Baker, 1928, and H. Mathiak, per. -omm., Horicon, Wisconsin). Several studies of iie Mississippi, Minnesota River and Black Rivers by the author have not revealed this 5pecies. During June 1977 two live specimens of A. suborbiculata were taken from Bluff Slough, ^ol 8 of the Mississippi River at La Crosse', Visconsin. This 90-meter-wide side channel, at ■lississippi River Mile 695, was being investi- gated by the author as part of an environmental ssessment for a sewer line to be constructed -nder the Slough by the city of La Crosse. The two living specimens, about 5 and 8 years of age, were in 1.5 meters of water on a sand bar that also contained some soft to firm mud, about 15 meters downstream from the proposed sewer line. Because of the obvious age and size dif- ference, reproduction in the area seems likely, at least on a limited basis. One specimen is in the Ohio State University Museum of Zoology, Col- umbus, Ohio 43210 (OSUM:1977:398:42780). Other naiad species collected alive at this site mcluded Anodonta grandis corpulenta Cooper, 1834, Amblema plicata plicata (Say, 1817) and Fusconaia flava (Rafinesque, 1820). Dead specimens were found of Lampsilis radiata luteola (Lamarck, 1819) and L. ventricosa (Barnes, 1823); sub-fossil specimens were found of Lasmigona complanata (Barnes, 1823) and Leptodeafragilis (Rafinesque, 1820). No rare or endangered species were found. Very few recent records exist for this species in the Upper Mississippi River. Two additional Wisconsin records for A. suborbiculata in the Mississippi River backwaters have been re- ported. A single fresh-dead specimen was found August 1978 at Mississippi River Mile 637.4, Pool 10, on the shore of an area known as Big Lake, 3.2 kilometers north of Prairie du Chien, Wisconsin (James Theler, per. comm. Dept. of Anthropology, University of Wisconsin-Madi- son, Madison, Wisconsin). Theler also found several other fresh-dead A. suborbiculata in the same general area June 1980. These specimens are all at The Ohio State University Museum of Zoology. 90 THE NAUTILUS April 30, 1981 Vol. 95(2) Fresh-dead shells of A. suborbiculata were found in 1976 in a then dried-up, small pond on the southern tip of Arsenal Island bordering Sylvan Slough, and in two other locations in Sylvan Slough in 1977 at Rock Island, Illinois, Mississippi River Mile 482.8 (Thomas Freitag, per. comm., Rock Island District, Corps of Engineers, Rock Island, Illinois). Four recently-dead shells were found in 1978 in water 0.75 meters deep in about a 2 hectare pond, about 10.4 kilometers NW of Muscatine, Iowa (Michael Knott, per. comm., Stanley Con- sultants, Inc., Muscatine, Iowa). Apparently this species is more common in the Upper Mississippi River than formerly believed, but the favored habitat makes collection dif- ficult. ACKNOWLEDGMENTS I wash to thank Dr. David H. Stansbery and Dr. Carol B. Stein for their comments on the early draft of this paper, and Leif Marking, Na- tional Fishery Research Laboratory, La Crosse, Wisconsin, for his comments on the final manu- script. LITERATURE CITED Baker, F. C. 1928. The fresh water moUusca of Wisconsin. Part II. Pelecypoda. Bull. Wisconsin Geological and Natural History Survey, 70:1-495. Coker, R. E. 1919. Fresh-water mussels and mussel indus- tries of the United States. Bull. Bureau of Fisheries 36: 11-89. Coon, T. G., .J. W. Eckblad, and P. M. Trygstad. 1977. Re- lative abundance and growth of mussels (Mollusca: Eula- mellibranchia) in pools 8, 9, and 10 of the Mississippi Ri- ver. Freshwater Biology 7:279-285. Danglade, E. 1914. The mussel resources of the Illinois River. Report U.S. Commissioner of Fisheries for 1913, Appendix 6:1-48. Dawley, C. 1947. Distribution of aquatic mollusks in Minne- sota. Amer. Midland Nat. 38:671-697. Flowers, W. 1975. Notes on the current status of Wisconsin Unionidae. Sterkiana 57:40-42. Fuller, S. L. H. 1978. Fresh-water mussels (Mollusca: Bi- valvia: Unionidae) of the upper Mississippi River: Observa- tions at selected sites within the 9-foot channel navigation project on behalf of the United States Army Corps of Engineers. Acad. Nat. Sci. Philadelphia. 401 pp. Grier, N. M. and J. F. Mueller. 1923. Notes on the naiad fauna of the Upper Mississippi River. II. The naiads of the upper Mississippi drainage. The Nautilus 36:96-103. Havlik, M. E. and L. L. Marking. 1981. A quantitative analysis of naiad mollusks from the Prairie du Chien, Wisconsin dredge material site on the Mississippi River. Bull. Amer. Malacol. Union, 1980, pp. 30-34. Havlik, M. E. and D. H. Stansbery. 1978. The naiad mollusks of the Mississippi River in the vicinity of Prairie du Chien, Wisconsin. Bull. Amer. Malacol. Union, Inc. (1977). pp. 9-12. Perry, E. W. 1979. A survey of Upper Mississippi River mussels. In: Rasmussen, J. L., editor. A compendium of fishery information on the Upper Mississippi River. Second Edition. Upper Mississippi River Conservation Committee, Rock Island, Illinois, pp. 118-139. Starrett, W. C. 1971. A survey of the mussels (Unionacea) of the Illinois River; a polluted stream. Bull. Illinois Natural History Survey 30:267-403. van der Schalie, H. and A. van der Schalie. 1950. The mus- sels of the Mississippi River. Amer. Midland Nat. 44(2): 448-466. Witter, F. M. 1883. The mollusca of Muscatine County and vicinity. The Muscatine Conchological Club, Muscatine, Iowa. S. E. Cassino and Co., Boston, pp. 3-24. Major Research and Identification Classic For Sale Lovell Reeve's CONCHOLOGIA ICONICA (1843-1878) This is the largest and most famous of the 19th century master works of conchology, containing 2,340 exquisite handpainted lithographic plates of many hundreds of new species. This excellent set, bound in contem- pory blue buchram in 26 volumes, contains all the then-known marine and land mollusks of the world. It lacks the freshwater parts deal- ing with such groups as Anodo7i and Unio. The set has unusually fine colored plates of Murex, Valuta, Cypraea, Pecten. Cornis. Tur- ns, Helix, Neritina, Mitra, and other popular groups. In addition, there are 87 plates photo- stated of rare, unattainable parts. Write: Dr. R. Tucker Abbott, P.O. Box 2255, Melbourne, FL 32901. Vol. 95(2) April 30, 1981 THE NAUTILUS 91 SOME PERUVIAN HYDROBIIDS, POTENTIAL SNAIL HOSTS OF PARAGONIMIASIS Emile A. Malek and W. Lobato Paraense Department of Tropical Medicine, Tulane Medical Center, New Orleans, LA, U.S.A. and Institute Oswaldo Cruz, Rio de Janeiro, Brazil Paragonimiasis, a lung fluke infection, is com- mon among humans and/or animals in the Far East, Southeast Asia, West Africa and the Americas. According to Abbott (1948) thiarids (melaniids), pleurocerids or assimineids are the usual snail first intermediate host in the Far East, but 3 out of 17 species of lung flukes there utilize hydrobiids. In West Africa the snail host is a thiarid. It has been established that hydro- biids (family Hydrobiidae) act in this capacity in the Americas. While it has been known for some time that the amphibious Poniatiopsis lapida^ia Say is the snail host of Paragonimus keUicotti in the United States (Ameel, 1934), only during the last decade did it become known that the small aquatic Aroapyrgus colombiensis is the snail host of P. caliensis in Colombia (Malek and Little, 1971) and that Aroapyrgus costaricensis (Morch, 1861) is the snail host of P. mexicanus in Costa Rica (Malek et al., 1975). Although the etiologic agent of human para- gonimiasis in Peru and Ecuador is not known, it is very likley that one or all of P. peruvianus. P. amazonicus and P. caliensis, which infect ani- mals in Peru, also causes the disease in humans. The snail hosts of Paragonimus spp. in Peru and Ecuador are still not known. However, on ac- count of similarities in the biology and details of the life cycle of the lung flukes in Central and South America, we believe that the snail hosts of paragonimiasis in Peru and Ecuador are also small aquatic hydrobiids, as they are in Colom- bia and Costa Rica. Among snails collected by the junior author in Peru in 1960 and 1961 are some small aquatic hydrobiids which we consider to be potential hosts of lung flukes in Peru and possibly also in Ecuador. These hydrobiids are: (1) Aroapyrgtis "Mlombiensis Malek and Little, 1971, Fig. lA. rhis species was collected from streams at lacos, Trujillo, Peru. Potamopyrgus mirandoi FIG. 1. A, Aroapyrgus colombiensis Malek and Little. 1971, male and female. B, Littoridina cumingii (Qrbiffny. 1835). male and female. Some internal organs show through the transparent shell especially the embryos in the ovoviviparous female A. colombiensis. In the male, part of the shell broken to expose verge, bp, brood pouch; e, eye; ec, egg capsule; em, embryo; g, gill; i, intestine; o, operculum; p, papilla on verge; r, rectum; t, tentacle; v, verge. Weyrauch, 1963, described as a new species in Peru on the basis of the shell only, is probably this species. (2) Littoridina cumingii (Orbigny, 1835) Fig. IB. This species was collected from streams near Lima, Peru. Orbigny (1835, 1835- 1846) based his description of the shell on material collected near Callao and Lima, Peru and at Valparaiso, Chile. Oiir bases for iden- tification of these two hydrobiids are the shell, 92 THE NAUTILUS April 30, 1981 Vol. 95(2) the operculum, the verge, details of the female reproductive system and the radula. Aroapyrgtcs colombiensis has a similar habitat in Peru as in Colombia, where it is the natural host of P. caliensis. The purpose of this short paper is to stimulate parasitologists to look for natural infections with Paragonimus spp. among hydrobiids in Peru and Ecuador, and to attempt to infect them experimentally. It should be noted that thiarids, in the same habitats with A. colombiensis in Colombia, are not infected with the lung flukes. LITERATURE CITED .\bbott, R. T. 1948. Handbook of medically important mol- ' lusks' of the Orient and the Western Pacific. Bull. Mvs. Camp. Zool. Harvard. Univ. 100:245-328. Ameel, D. J. 1934. Paragonimus, its life history and distri- bution in North America and its taxonomy (Trematoda: Troglotrematidae). Amer. Jour Hygiene 19:279-317. Maiek, E. A. and M. D. Little. I'm. Aroapyrgus colombien- sis n. sp. (Gastropoda; Hydrobiidae), snail intermediate host of Paragonimus caliensis in Colombia. Thf Nautilus 85:20-26. Malek, E. A., R. Brenes and G. Rojas. 1975. Aroapyrgus costari^ensis. hydrobiid snail host of paragonimiasis in Costa Rica. Jour. Parasit. 61:355-359. Orbigny, A. 1835. Synopis terrestrium et fluviatilium Mol- luscorum in suo per America meridionalem itinere collec- torum. Mag. Zool. 5:1-44. 1835-1846. Voyage dans rAmerique Meridio- nale. Paris (Vol. 5. Mollusques). Weyrauch, W. K. 1963. Cuatro nuevas especies de Hydro- biidae de Argentina y Peru (Gastropoda; Prosobranchia). Acta Zoologica LiUoawi 19:243-259. GUIDE TO THE NUDIBRANCHS OF CALIFORNIA INCtUDINC MOST SPECIES FOUND FROM AtASKA TO OREGON BY Gary R. McDonald and Itditt'd B\ R JuLker Destined to be the "bible" for tidepool and scuba biologists, the Guide to the Nudthranchi ol Caliiornia will equally serve those researchers from Alaska and Pacific Canada to Oregon. The extensive information on the specialized foods and habitats of each species will aid not only in identification but also in ecological analyses. Unique among similar guides, this book has the advantage of ex- tensive keys, authoritative information and convenient phylogenetic organization. This book will be welcomed by marine biologists, amateur naturalists, marine aquarium enthusiasts, and students ot oceanography. Years in the making, this compact account gives the scienlilic essentials to all the known nudibranchs snails of California, including the higher classification and descriptions of each genus with their lype-species. With top quality in photography and understandable, concise morphological descriptions, identilu ations ot species are made much easier Iames W, Nybakken Abbott} 1 12 color plates, b4 pages Sottcover: $13 50 \xr sJP"-^ • BIOLOGY ;■ ~iM-' • KEY TO SPECIES ' ■^. . GENERIC DESCRIPTIONS ' • SPECIES DESCRIPTIONS • 1 12 COLOR PLATES Of LIVING ANIMALS • COLLECTING TECHNIOUES PHOTOGRAPHING TECHNIQUES i f' _ american malacologists >( BUSHliliS OF DlSnNCriVE BOOKS ON MOLUSKS p O BOX 2255 MELBOURNE FLORIDA 32901 • ANATOMY • BIBLIOGRAPHY Vol. 95(2) April 30, 1981 THE NAUTILUS 93 FRESHWATER NAIADES OF EAGLE CREEK, A TRIBUTARY OF THE KENTUCKY RIVER (UNIONIDAE) Ralph W. Taylor Department of Biological Sciences Marshall University Huntington, WV 25701 ABSTRACT A survey of the freshwate?- Naiades of Eagle Creek, a tributary of the Kentucky River, was carried out during the summer of 1980. Ten stations were collected at irregular intervals during the summer. A total of twenty-one species are reported as currently occurring in the stream. Two species, Pleurobema clava and Cyclonaias tuberculata, may no longer be present in the stream as they were found only as dead shells. All other species enjoy wide-spread distribution and good numbers are present. Anodontoides ferussacianus, Simpsonaias ambigiia and Elliptio crassidens are reported for the first time as occurring in the Kentucky River system. As part of a continuing effort to document freshwater mussel faunal assemblages of smaller Kentucky streams, this paper reports work carried out during the summer of 1980 on Eagle Creek, a major downstream tributary of the Kentucky River. Eagle Creek enters the Kentucky River near the village of Worthville, Carroll County, Kentucky, at a point some seven miles from the confluence of the Kentucky with the Ohio River at Carrollton, Kentucky (Fig.l). The Kentucky River proper originates in the mountains of eastern Kentucky which are located within the Cumberland Plateau. The headwaters consist of three main branches, the North, Middle and South Forks. Three addi- tional major tributaries flow into the Kentucky River along its 400 mile length. They are: (1) the above-mentioned Eagle Creek, (2) the Dix River and (3) the Red River. . The only previous study concerned with the "reshwater naiades of this drainage was carried )ut by Danglade (1922) some 60 years ago. Dur- ng the summers of 1919-1920, he surveyed the nussel resources of the mainstem Kentucky liver with an eye on the commercially valuable ;hells which fed the burgeoning shell-button in- lustry. In 1920, a single 35 mile stretch of river, vhich he monitored regularly, produced 87 tons if desirable shells. A total of 40 species of nussels (22 with commercial value) was re- VIG. 1. Map of northern central Kentucky showing collecting stations (blafk dots) on the Eagle Creek. ported as occurring in the drainage (Table 1). These data indicate a productive stream of good water quality and readily available suitable habitat. Since the studies of Danglade the river has been modified. Extensive "improvements" 94 THE NAUTILUS April 30, 1981 Vol. 95(2) TABLE 1. Freshwater Naiades of Kentucky River as Reported by Danglade (collected summers of 1919-1920). Name as used by Danglade usage AlasntidontB marginata Alasmidonta minor Anodonta grandis Anodonta imbecillis Cyprogenia irrorata LuRipsilis alata Loapstlis anodontotdcK Uinps i 1 i s f a 1 1 ac i osa Lampsilis graolis Lamps i lis ligament) na Lompsilis lutcola Lampsilis aultiradiata LanpsiliK parva Lampsilis recta Lampsilis ventricosa Obliquaria reflexa Obovaria lens Plagiola donacifomis Plagiola clcgans Plcurobcffla clava Ptychnbranchus phaseolu! Quadrula coccinea Quadrula cylindrica Quadrula granifera Quadrula heros Quadrula kirtlandiana Quad ru la 1 ac)i rymosa Quadrula pustulata Quadrula pustulosa Quadrula rubiginosa Quadrula sol ida Quadrula subrotunda Quadrula undulata Strophitus cdentulus Symphynota complanata Symphynota costata Tn togonia tuberculata Truncilla rangiana Truncil la triquetra Unio gibbosus Alasmidonta marginata Say, 181S Alasmidonta viridis iRaf.. 1820) Anodonta g. grandis Say, 1$29 Anodonta imbecillis Say, IS29 Cyprogenia stegaria (Kaf., 1820) Potamilus alatus (Suy, 1817) Lampsilis teres form anodontuides (Lea, 1B31) Lampsilis teres form teres (Raf., 18201 Leptodea fragilis (Kaf., 1820) Actinonaias ligamentinu carinata [Barnes. 1823 Lampsilis radiata luleola (Lam., 1819) Lampsilis fasciola Raf.. 1820 Toxolasma parvus (Barnes, 1823) Ligunia recta (l.am., 18191 Lampsilis ventricosa (Barnes, 1S23) Obliquaria reflexa Haf . . 1820 Obovaria subrotunda (Raf., 1820) Truncilla donaciformis (Lea, 1827) Truncilla truncata Haf., 1820 Pleurobema clava (Lam., 1619) Ptychftbranchus fasciolaris (Raf., 1820) Pleurobema sintoxia (Raf., 1820) Quadrula cylindrica cylindrica (Say, 1817) Cyclonaias tuberculata (Raf., 1820) Megalonaias nervosa (Raf,, 1830) Fusconaia maculata kirtlandiana (Lea, 1834) Quadrula quadrula (Raf., tS20) Quadrula iiodulaLa (Raf., 1820) Quadrula pustulosa pustulosa (I.ea, 1831) Fusconaia flava (Raf.. 1820) Pleurobema cordatum (Haf., 1820) fusconaia maculata maculata (Raf. , t82U) Amblema plicata plicata (Say, 1817) Strophitus undulatus undulatus (Say. 1817) Lasmigona complanata (Barnes. 1823) Lasmigona costata (Raf.. 1820) Tritogonia verrucosa (Raf., 1820) Epioblasma torulosa rangiana (Lea. 1039) EpiobJasma triquetra (Raf.. 1820) El liptio dilatiita (Raf., 1820) METHODS Ten stations, where good naiad populations existed, were established and visited at ir- regular intervals throughout the summer of 1980. Shells were hand picked from the shal- lows. Additionally fresh dead valves, deposited as middens by muskrats and raccoons, are in- cluded in Table 2. Specimens found only as dead, badly eroded shells are indicated as such. The material collected was returned to the labor- atory, cleaned, identified and catalogued in the Marshall University Malacological Collections. Dr. David H. Stansbery of the Ohio State University Museum of Zoology very kindly con- firmed identifications of some specimens. Voucher specimens have been placed with O.S.U.M. All names included herein are those used by Stansbery (1979). Collecting Site Localities 1. Scott Co. -Co. Rd. 620 at Porter Rd. near Salem Church. 2. Scott Co.-Pokeberry Rd., % mi. W of 1-75 near village of Sadieville. TABLE 2. List of species found at each location. Eagle Creek. Kentucky 1980 Survey. (C) = common. (M) = moderate- ly common, (R) = rare. for navigational purposes have been made, and additionally the stream has suffered from man's other activities in the last 80 years (i.e., mining, industry, agriculture and sewage). Eagle Creek, on the other hand, remains essentially unchanged today. There are no dams, no industries and only limited human sewage input along the Ca. 80 mile length of the stream. Eagle Creek originates in the Bluegrass region of central Kentucky just north of Lex- ington and flows in a northwesterly direction through rolling knobs past horse and tobacco ferms to the Kentucky River. No towns of ap- preciable size exist within the drainage of this creek. The creek for the most part never ex- ceeds 15 m in width or 2 m in depth. Anodonta g. grandis Say, 1829 (C) XXXXXXXXX Anodontoides fcrussacianus (Lea, 1834) (R) X Strophitus u. undulatus (Say, 1817) (C) X X X X X X X Alasmidonta viridis (Raf., 1820) (C) X X X X X X Sinpsonaias ambigua (Say. 1825) (M) X X Lasmigona complanata (Barnes. 1823) (C) X X X X Lasmigona costata (Raf., 1820) (R) X Tritogonia verrucosa (Raf., 1820) (C) X X X X Quadrula quadrula (Raf., 1820) (M) XXX Amblema p. plicata (Say. 1817) (M) X X X X Fusconaia flava (Raf.. 1820) IM) X X X X Cyclonaias tuberculata (Raf., 1820)« (R) X X Pleurobema clava (Lam., 1819)* (fi) X Elliptio c. crassidens (Lam.. 1819) (R) X Elliptio dilatata (Raf., 1820) (C) X X X X X X Ptychobranchus fasciolaris (Baf., 1820) (M) X X Leptodea fragilis (Raf.. 1820) (M) X X X X Potamilus alatus (Say. 1817) (C) X X X X X Toxolasma parvus (Barnes, 1823) (R) X Lampsilis r. lutcola (Lam., 1819) (C) XXXXXXXX Lampsilis ventricosa (Barnes. 1823) (C) X X X X X •Found only as badly eroded dead shells Vol. 95(2) April 30, 1981 THE NAUTILUS 95 3. Owen Co. -Co. Rd. 1883, 1 mi. NW of Jet. with Co. Rd. 2018, 2 mi. W of village of Nat- lee. 4. Owen Co. -Co. Rd. 1739, behind Mussel Shoals Baptist Church, 1.5 mi. NE of Jet. with St. Rd. 845. 5. Owen Co.- Jet. of St. Rd. 330 at St. Rd. 845 under bridge, area locally known as Lusby's Mill (old milldam still present). 6. Grant Co. -Co. Rd. 1132, 1.5 mi. N of Jet. Calendar Rd., 3 mi. N of village of Jones- ville. 7. Grant Co. -Co. Rd. 1132, 1.5 mi. S of Jet. with St. Rd. 467 at Ford's Mill Rd. 8. Gallatin Co. - St. Rd. 467, 4.2 mi. E of village of Sparta, 1.2 mi. W of Gleneoe. 9. Gallatin Co. -St. Rd. 467, 1.2 mi. ENE of vil- lage of Sparta at Louisville and Nashville Railroad crossing. 10. Owen Co. -St. Rd. 35, under bridge at Sparta. RESULTS Twenty-two species of freshwater naiades were found in Eagle Creek (Table 2). Two species, Cyclonaias tuberculata and Pleurobema clava. were found only as badly eroded dead shells and may be assumed to be either very rare or no longer present in this stream. Anodon- tx)ides fertcssacianus. Simpsonaias ambigua. Lasmigona costata. Elliptio crassidens and Tox- olasma panms were found only rarely. All other species were found widely distributed and in fairly good numbers throughout most of the stream. Anodonta g. grandis was found at every station and Lampsilis r. luteola was found at every station except Station No. 1. Anodontoides fenissacianics, Simpsonaias am- bigua and Elliptio crassidens are reported herein for the first time as occurring in the Ken- tucky River system. Specimen Shells Offering microscopic and miniature (to '/» inch) shells from the Florida Keys, with accurate locality data Also unsorted grunge: write for list. Margaret Teskey P.O. Box 273 Big Pine Key. H. 330J,3 CONCLUSIONS The Kentucky River around the turn of the Twentieth Century was a stream of relatively high quality and supported a freshwater naiad population of considerable commercial value (Danglade, 1922). Whether that is still the case remains to be seen. Future investigators may wish to take a second look at the Kentucky and see what effects habitat modifications (i.e, pollu- tion, damming, etc.) have had. One must assume that as in other comparable streams the impact has been great. I would be very surpised if any single location in the Kentucky still supported mussels in commercial quantities. I would also be surprised if many of the species reported by Danglade were still in the river, even in limited numbers. Among this doubtful group would be Quadmla cylindrica, Actinonaias I. carinata, Lampsilis teres, Pleurobema clava, Epioblcbsma t. rangiana and Epioblasm,a triquetra. The future outlook for our larger streams is not one of total dispair. It may well be that if and when the larger streams are cleaned up, to a point where they again afford suitable habitat for naiades, lesser tributaries such as Eagle Creek may produce the restocking material for these larger waterways. The large number of species and good num- bers of individuals in Eagle Creek indicate a stream of rather high quality that is under little or no environmental stress. Conservation ef- forts by state and federal agencies, aimed at protecting these small stream refugia, may be the key to the continued existence of freshwater naiades in North America. LITERATURE CITED Danglade, Earnest. 1922. The Kentucky River and Its Mussel Resources. U.S. Bureau of Fisheries Doc. 934:1-8. Stansbery, David H. 1979. Naiad MoUusks of the Ohio River Drainage System. The Ohio State University Museum of Zoology, 1-p mimeo. PHILLIP W. CLOVER COLLECTOR & DEALER IN WORLD WIDE SPECIMEN SEA SHELLS p. o. Box 83 Glen Ellen, CA 95442 FREE SHELL LISTS SPECIALISTS IN CYPRAEA. CONUS, VOLUTA margineCla, Mif RA, MUREX 96 THE NAUTILUS April 30, 1981 Vol. 95(2) ANEW SPECIES OF CROSSLANDIA (NUDIBRANCHIA: DENDRONOTACEA) FROM THE GULF OF CALIFORNIA Leroy H. Poorman' Museum Associate Los Angeles County Museum of Natural History Members of the dendronotacean nudibranch family Scyllaeidae have been reported through- out the equatorial and temperate seas for over two centuries. Seba (1743) first published an il- lustration of one of these species as Pullus Ranae Piscatricis Quartae. He thought is was the young of a fish and figures it in an inverted position. Several years later, Linnaeus (1758) named this species Scyllaea pelagica. thus establishing the binomial. Linnaeus, however, continued the error of describing the animal up- side down. Presently, Scyllaeidae contains three genera: Scyllaea Linnaeus, 1758, Crosslandia Eliot, 1902, and Notobryon Odhner, 1936. Character- istics of the genera are detailed in Odhner (1936: 1096-1103). Crosslandia daedali Poorman and Mulliner, new species Description -Body long, about 25 mm in length, narrow and deep; produced forward in a long neck and posteriorly in a short tail (Fig. 1). Wide winglike lobes extended laterally along the middle one-half of each side; lobes irregularly notched and digitate (Fig. 2). Head blunt, with an abbreviated vellum on upper portion of the buccal opening. Rhinophores retractile in hollow of flaring rhinophore sheaths; conical, perfoliate with 22 leaves. Numerous fimbriating retracta- ble branchial tufts irregularly placed on the in- side surface of the lobes and the dorsal area be- tween (Fig. 2). A caudal crest extended over the tail section. Color of animal greenish brown-orange; longi- tudinal fine chestnut brown lines with some white lines on sides and undersides of lobes; a and David K. Mulliner Research Associate San Diego Museum of Natural History Balboa Park, San Diego, CA 92112 FIG. 1. Sketch of a living Crosslandia daedali (25 mm in length) crawling over Padina; lateral mew, anterior to the right. Dramng try A. D'Attilio. > 15300 Magnolia Street, Sp. 55, Westminister, CA 92683. FIG. 2. Dorsal view o/Crosslandia daedali, shoacing the bran- chiae on the inner surface of the body lobes and various inter- nal organs, a, jaw plates: b. pharyngeal bulb: c, gaglion; d, liver mass: e, three-part hermaphroditic gland: f, stomach: g, heart: h, ana.'t: i, branchial tufts. Drawing by A. D'Attilio. Vol. 95(2) April 30, 1981 THE NAUTILUS 97 narrow light-colored border along the thin edge of the rhinophore sheaths, along the sides of neck, around edge of lobes and crest of tail; ir- regular black to brown blotches on some ani- mals. Brilliant blue small round spots medially along sides of body, about 6 in number, about 5 spots medially on the dorsum, most spots with fine black borders. A row of 4-6 flesh-colored, sharply conical tubercles along median line of each side of the animal. Jaw plates (Fig. 3) large and hinged dorsally with the muscles attached at the bend and FIG. 3. Lateral mew of the jaw o/Crosslandia daedali. Draw- ing by A. D'Attilio. covering the large tessellated stiff cheeks. The radula with 15 longitudinal rows of teeth denti- culated on both sides (Figs. 4 and 5); central tooth slightly flattened, smaller than the laterals. The radula formula 15x25«1.25. The hermaphrodite gland (Fig. 6) of three masses, two posterior, one on each side of a liver mass located in the mid-dorsal region; the third mass located anterior on the right side of the animal. The genital opening beneath the rhino- phore sheath on the right side. The spermatheca X)nnecting directly into the vagina. The large ampulla connected by a long convoluted tube to ;he genital orifice. The liver in two large masses interior and posterior. The stomach armed with 14 plates in a constricting ring. The anus located nidpoint of the side below the right lobe. Type-locality -Tmajas, Bahia de Bacochibam- )o, Sonora, Mexico (27°56'N; 110°59'W). Material examined -Eoloty^e, San Diego Natural History Museum, Department of Ma- ine Invertebrates, Type Series No. 514. Col- FIG. 4, Sketches of various views of assorted radiilar teeth. Draunngs by A. DAttilio. lected at Tinajas, Bacochibampo Bay, Sonora Mexico (27°56'N; 110°59'W); 4 December 1975, by Roy and Forrest Poorman. Paratypes, col- lected with the holotype specimen, are deposited in the malacology (or marine invertebrate) col- lections of the San Diego Natural History Museum (SDNHM Type Series No. 515), the Los Angeles County Museum of Natural History (LACM 1910), and the United State National Museum (USNM 795112). Additional material was collected at Tinajas, Sonora, Mexico, on 23 October 1976. Also, 4 specimens were collected at Bahia de Algo- dones, Sonora, Mexico, and 1 specimen was col- lected on the east side of Punta Cuevas, Bahia de San Carlos, Sonora, Mexico. Etymology -This species is named in recogni- tion of the Greek, Daedalus. When the animal is at rest, it attaches to Padina with the posterior part of the foot. With its lateral lobes extended 98 THE NAUTILUS April 30, 1981 Vol. 95(2) FIG. 5. Scanning electron micrographs of the lateral teeth of Crosslandia daedali. Top and middle., approximately 6S5 x . Bottom, approximately ISOOx. Microscopy by Robert Petty- john. FIG. 6. Sketch of the viscera o/ Crosslandia daedali. a, liver mass; b, stom,ach; c, hermaphroditic gland. Drawing by A. D'Attilio. and head and neck raised, it appears to reach outward from the stem. Just so must the legend- ary Daedalus have looked as he fastened on his feathers and paused before launching into his winged flight. DISCUSSION Crosslandia da£dali has been found only on the Sonoran shores of the Gulf of California, in the Guaymas area. It is the first record of the genus from the Eastern Pacific. Its known con- gener, C. viridis Eliot, 1902, has been reported only from Zanzibar, the Red Sea and Japan. There are distinctive internal anatomical features which distinguish these two species. In Crosslandia daedali the masticatory edge of the jaws is smooth and flexible, bending outward and forming stiff cheeks which are attached full length. By contrast, a slit separates the bottom one-third of the jaw plate at the bend in C. viridis. The spermatheca of C. daedali is attach- ed directly to the vagina, whereas in C. viridis it is connected by a long tube. Externally, the new species consistently Vol. 95(2) April 30, 1981 THE NAUTILUS 99 shows a narrow, light-colored border along the sharp edges of the body and all the appendages. This is not apparent on Crosslandia viridis. Crosslandia daedali consumes small hydroids growing on the surface of the algae. The nudi- branchs graze slowly over the surface or attach to the stems with a small central portion of the foot, resting with the head and neck extended and the lateral lobes projecting at an angle of about 45° from the vertical. Because of coloring and irregular shape, these animals are mime- tically camouflaged, resembling another piece of torn algae. ACKNOWLEDGMENTS We thank Mrs. Laura Shy for field assistance; Mr. Robert Pettyjohn for doing the scanning electron microscopy; Mr. Anthony D'Attilio (De- partment of Marine Invertebrates, San Diego Natural History Museum) for the anatomical drawings; and especially Dr. Hans Bertsch (formerly Curator of Marine Invertebrates at the San Diego Natural History Museum) for his editorial assistance in putting this paper together. LITERATURE CITED Eliot, C. N. E. 1902. On some nudibranchs from Zanzibar Proc. Zool. Soc. London 2:62-72; pis. 5-6; text figs. 2-5. Linnaeus, C. 1758. Systema naturae, tenth edition Odliner. N. H. 1936. Nudibranchia Dendronotacea. A revi- sion of the system. Me7n. Mus. Roy. d'Hist. Nat. Belgigue 2nd ser. 3:1057-1128; 1 pi.; 47 text figs. Seba, D'Albert. 1743. Locupletissimi rerwn naturalimn thesauri accurata descriptio et iconihus artificionissi- mis. Amstelodami. 'SPECIAL OFFER FROM KRAUS REPRINT^ 30% Discount Applied to Orders Received by May 31, 1981 on Back Volumes of A Quarterly Devoted to the Interests of Conchologists Volumes 1-40 and General Index 1-34. Philadelphia, Pa., 1886-1926/27. cloth $578.00 paper $494.00 per vol. paper $ 12.00 Gen. Ind. 1-34 (1886-1921) paper $ 14.00 Later volumes available; please inquire. 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MOLLUSK VOUCHER SPECIMENS It is becoming increasingly important for future research purposes that an identified sam- oling of species mentioned in publications be deposited in a permanent, accessible museum ipecializing in mollusks. This is particularly ;rue of mollusks used in physiological, medical, jarasitological, ecological, and experimental projects. Several museums of natural history have ex- tensive modern facilities and equipment for the housing and curating of voucher specimens. Material should be accompanied by the identifica- tion, locality data and its bibliographic reference. There is no charge for this permanent curating service, and catalog numbers, if desired, will be sent to authors prior to publication. WANTED - OLD SHELL BOOKS Will pay good prices for libraries, second- „„. „„_ __., hand books and reprints on mollusks, shells 305-725-2260) or write: R Tucker Abbott and conchology. Back numbers of The Nauti- lus, vols. 40-71 wanted, $1.50 each. Phone (1- American Malacologists, Inc.. P. 0. Box 2255 Melbourne, FL 32901. Free appraisals. americanmalacologists, inc. PUBLISHERS OF DISTINCTIVE BOOKS ON MOLLUSKS THE NAUTILUS (Qmrterly) MONOGRAPHS OF MARINE MOLLUSCA STANDARD CATALOG OF SHELLS INDEXES TO THE NAUTILUS (Geographical, vols 1-90; Scientific Names, vols 61-90) REGISTER OF AMERICAN MALACOLOGISTS JULY 10, 1981 THE NAUTILUS ISSN 0028-1344 Vol. 95 No. 3 A quarterly devoted to malacology and the interests of conchologists Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker. Editor-in-Chief: R. Tucker Abbott EDITORIAL COMMITTEE CONSULTING EDITORS Dr. William J. Clench Curator Emeritus Museum of Comparative Zoology Cambridge, Mass. 02138 Dr. William K. Emerson Department of Living Invertebrates The American Museum of Natural History New York, New York 10024 Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, Ohio 43210 Dr. James H. 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Box 2255, Melbourne, Florida 32901 Mrs. Cecelia W. Abbott Business and Subscription Manager P.O. B(« 2255 Melbourne, Florida 32901 Tlie Nautilus (USPS 374-980) ISSN 0028-1344 OFFICE OF PUBLICATION American Malacologists, Inc. (United Parcel Address: 2208 South Colonial Drive, Melbourne, FL 32901) Mail: Box 2255, Melbourne, FL 32901 Second Qass Postage paid at Melbourne, Florida and other post offices Subscription Price: $12.00 (see inside back cover) $14.00 (foreign); institutions $18.00 THE NAUTILUS Volume 95, number 3 - July 10, 1981 ISSN 0028-1344 CONTENTS William K. Emerson Two New Indo-Pacific Species oiMorum (Gastropoda: Tonnacea) 101 William K. Emerson, George L. Kennedy, John F. Wehmiller, and Everly Keenan Age Relations and Zoogeographic Implications of Late Pleistocene Marine Invertebrate Faunas from Turtle Bay, Baja California Sur, Mexico 105 Dorothea S. Franzen Catinella vagans (Pilsbry) and a New Species of Catinella (Succineidae Pulmonata) from the Shore of Lake Waccamaw, North Carolina 116 Barbara W. Myers and Anthony D'Attilio The Morphology and Distribution of Ocenehra grippi (Muricidae: Ocenebrinae) 124 Hugh J. Porter and Glenn Safrit The Marine Faunal Zones of North Carolina, with New Molluscan Records 127 R. S. Harvey Recolonization of Reactor Cooling Water System by the Asiatic Clam Corbicula fluminea 131 Roy S. Houston and Edward B. Hatfield The Reproductive System of the Western Atlantic Anachis avara (Gastropoda: Columbellidae) 136 Robert M. Severns Growth Rate Determinations of Achatinella lila, A Hawaiian Tree Snail 140 Amy Lyn Edwards and Celeste Marie Humphrey An Electrophoretic and Morphological Survey oi Busycon Occurring in Wassaw Sound, Georgia 144 James F. Quinn, Jr. The Gastropods, Calliostoma orion Dall, 1889 (Trochidae) and Heliacus (GyrisctLs) worsfoldi N. Sp. (Architectonicidae), from the Bahama Islands 150 Publications received ii Recent deaths ii THE NAUTILUS July 10, 1981 Vol. 95(3) PUBLICATIONS RECEIVED Roth, Alexander, Jr. 1980. Molluscan Melange: How to Prepare Your Molluscs for Eating. 148 pp., illus. Aljemasu Enterprises, P. 0. Box 7867, Tamuning, Guam 96911. Paperback, $6.95. A charming book containing many new and old recipes for scallops, oysters, escargots, squid, and various lesser mollusks. The culinary information is far better than the malacological accounts. Roth, Alexander, Jr. 1980. Mollusks of the Southem Ma- rianas Islandx. 110 pp. Aljemasu Enterprises, Guam. An informal checklist of mollusks found in Guam. Contains a phylogenetic listing of most families of mollusks. List is marred by inclusion of numerous species guessed to be "probable on Guam" which doubtlessly will never extend their ranges to that archipelago. Farmer, Wesley M. 1980. Sea-Slug Gastropods. W. M. Farmer Enterprises, Inc., P. 0. Box 26653, Tempe, AZ 85282. 177 pp. Technical coverage of Pacific coast nudi- branchs, aphysiids, sacoglossates, one Titiscania (no Lamellaria sea slugs) and Onchidella, with drawings of animals, radulae and ranges. Author recommends reader obtain set of 60 pencils in order to color the draw- ings! Index consists only of list of authors with the species they have described. Unfortunately the preface is poorly written, but does not detract from the usefulness of the book. Breisch, Linda L. and Victor S. Kennedy. 1980. A Selected Bibliography of Worldwide Oyster Literature. Publication no. UM-SG-TS-80-11, Sea Grant Program, Univ. Mary- land, 1224 H. J. Patterson Hall, College Park, MD 20742. Contains titles and references to 2837 published articles, 810 reports, and 134 theses, with subject indices to each. Waller, Thomas R. 1981. Functional Morphology and Devel- opment of Veliger Larvae of the European Oyster, Ostrea eduiis Linne. Smithsoiitan Contributions to Zoology, no. 328, 70 pp., 152 SEM figs. Many new structures dis- covered. Dell'Angelo, Bruno and Angelo Tursi. 1978. Guida biblio- grafica ai Chitoni (Polyplacophora): 1970-1978. Oebaiia, vol. 4, pp. 79-151. [living and fossil]. Kaas, Piet and Richard A. van Belle. 1980. Catalogue of Living Chitons (MoUusca: Polyplacophora). 144 pp. Dr. W. Backhuys, Publ., Oudorpweg 12, Rotterdam RC 3062, Netherlands. Hardback. About $20.00 U.S. (no bibliog- raphy, see above). Bruce, J. I. et al., editors. The Mekong Schistosome. Mala- cological Review. Chapter on snail host, Triatla aperta. $26.00. Malacological Review, P. 0. Box 420, Whitmore Lake, MI 48189. RECENT DEATHS Joshua L(ongstreth) Baily, Jr. died on April 18, 1981, in Mission Hills, California, at the age of 92. He was born Jan. 29, 1889, in Philadel- phia, PA. He graduated from Haverford College (A.B., 1912; A.M. 1913) and Johns Hopkins (Sc.D., 1938). A Quaker, he served in the American Red Cross in World War I. He was a past-president and charter member of the A.M.U. and later in life moved to California where he was associated with the San Diego Society of Natural History where his collection and library are now housed. A biobibliography appears in Festimis, vol. 8, no. 5, p. 63 and in American Malacologists, 1st ed., 1973, p. 195. Ralph H(amilton) Humes died on April 17, 1981, in Leesburg, FL, at the age of 79. He was born Dec. 25, 1902, in Philadelphia, PA. He was a well-known sculptor and an active collector and student of Florida and Cuban tree snails of the genus Liguus for many years. His collection was given to the Everglades National Park museum. A short biography appears in Ameri- can Malacologists, 1st ed., p. 312. He is survived by his wife, Janet C. Humes, 2616 Azalea Pt., Leesburg, FL. 32748. Vol. 95(3) July 10, 1981 THE NAUTILUS 101 TWO NEW INDO-PACIFIC SPECIES OF MORUM (GASTROPODA: TONNACEA) William K. Emerson American Museum of Natural History New York, New York 10024 ABSTRACT Morum (Oniscidia) macdonaldi, n. sp. (type locality Kwajalein Atoll, Marshall Islands) and M. (0.) joelgreenei, n. sp. (type locality, GulfofDavao, Mindanao Island, Philippines) are described. The former taxm represents the first Microne- sian record for the genus Morum in the western Pacific Ocean. Nineteen living species o/ Morum (sensu lato) are now known (IS in the Indo-Pacific, two in the eastern Pacific, and four in the western Atlantic). Some of these taxa are poorly known and require additional study. Although the genus Morum (sensu lato) was more widely distributed during the Tertiary with species known from Europe, India, In- donesia, New Zealand, Japan, and the Americas (from Florida to Peru), the surviving members of the subgenera Oniscidia and Herculea are best represented in the western Pacific Ocean. Here most of the species live in the waters off the Old World continent, ranging from southern Japan, the Ryukyu Archipelago, Taiwan, to the Philippines, and are found in the southwestern Pacific waters in New Guinea, New Caledonia, and eastern Australia. One species (Morum pon.derosum). however, occurs in the south- central Pacific at Pitcairn Island; it is also recorded from the Ryukyu Archipelago, New Caledonia, and off Queensland, Australia. With the discovery of the new species described lerein from the Marshall Islands, the genus is low known from Micronesia. In contrast, the discovery of another new species in the Philip- aines is not unexpected, as many new and other- A'ise interesting mollusks have been recently recovered in this archipelago by industrious col- ectors. In addition to the two species described below, he following Recent species of Morum are mown, 1. Indo-Pacific, M. (Oniscidia): cancella- um (Sowerby, I, 1824); exquisitimi (Adams and leeve, 1848); grande (A. Adams, 1855); macan- Irewi (Sowerby, III, 1889); praeclarum Melvili, 919; bruuni Powell, 1958; teramachii Kuroda and Habe, in Habe, 1961; uchiyamai Kuroda and Habe, in Habe, 1961; watsoni Dance and Emerson, 1967; kurzi Petuch, 1979; M. (Hercu- lea) ponderosum (Hanley, 1858). 2. Eastern Pacific, M. (Morum) tuberculosum (Reeve, 1842); M. (Oniscidia) veleroae Emerson, 1968. 3. Western Atlantic, M. (Morum) oniscus (Linne, 1767); M. (Oniscidia): dennisoni Reeve, 1842); strombiformis (Reeve, 1842); matthewsi Emer- son, 1967. One or two of these nominal species are per- haps best considered a nomen iyiquirendwm, un- til additional specimens can be obtained. A few others require anatomical study in order to determine their biological validity. Family Cassidae Swainson, 1832 Genus Morum Roding, 1798 Type species by monotypy: Morum purpureum Roding, 1798 [ = Strombus oniscus Linne, 1767], Recent, western Atlantic. Morum s.s. is repre- sented by a few Plio-Pleistocene to Recent, New World species with knobbed, subcylindrical shells. Subgenus Oniscidia Morch, 1852 Type species by monotypy: Oniscia cancellata Sowerby, I, 1824, Recent, Indo-Pacific (See I.e. Z.N. Opinion 1040, 1975). Represented by several Eocene to Recent, largely world-wide species with extended spires and cancellate 102 THE NAUTILUS July 10, 1981 Vol. 95(3) FIGS. 1-3. Morum (Oniscidia) joelgfeenei n. sp. x 1. I, Holotype, dorsal, parietal and apertural vieu's. 2, Paratype A. dorxal and apertural views. 3, Paratype B. dorsal and apertural inews. FIGS. 4-6. Morum (Oniscidia) macdonaldi, n. sp., x 2. 4, Holotype. dorsal, parietal, and apertural in,ews. 5, Paratype A, dor- sal and apertural views. 6, Paratype B. dorsal and apertural views; note immature apertural chararters. FIG. 7. Morum (Oniscidia) kurzi Petuch, 1979. x 2; Delaware Mws. Nat. Hist. no. 126S93: holotype, dorsal and apertural views. All photographs try S. S. Horenstein. sculpture of broad axial ribs and narrower spiral cords. Morum (Oniscidia) joelgreenei, new species Figs. 1-3 Description- Shell trian^larly ovate, moder- ately stocky with a wide shoulder, attaining 46 + mm (holotype, fig. 1); spire extended; proto- conch of 3V2 smooth whorls, erect and papillate; 5+ postnuclear whorls cancellated, with 10 moderately weak spiral cords, crossed by 10 conspicuous, spinose axial ridges (varices) per Vol. 95(3) July 10, 1981 THE NAUTILUS 103 whorl; juncture of spiral cords and varices with a sharp, hooked spine; spines most prominent at the shoulder; intervarical areas with 8 to 10 evenly spaced axial lamellae; parietal shield large with outer margin raised and covered with numerous pustules; parietal pustules linear near the aperture, pimplelike on the outer margin; outer lip thickened, crenulated and toothed; 9 primary teeth form linear bifid projections on the inner labial margin, secondary teeth con- fined to postmarginal surface; anal sulcus shal- low; siphonal canal short, recurved, open. Coior- Nucleus shiny, light- tan; postnuclear whorls with whitish base color, overlaid with flecks of reddish brown; 4 widely interrupted brownish spiral bands on body whorl (1 band on shoulder, 2 on either side of midbody area, 1 near the base); darkest coloration of bands on side facing apertural face of each varical spine and on edge of outer lip; bands more defused in Paratype B; parietal shield glazed, buff color with posterior surface tinged a pale lavender- white; pustules white; outer lip glazed, buff col- or with dark-brown blotches (4 major blotches formed at labial base of spiral bands and 2 secondary blotches between each spiral band). Material examined - E.o\QtyTpe A.M.N.H. 203719 (fig. 1), 46.4 mm in length, 29.8 mm in width; Paratype A, A.M.N.H. 201362 (fig. 2), 39.4 mm in length, 26.1 mm in width (both ex- Joel Greene collection from type locality); Paratype B, (fig. 3), 35.3 mm in length, 22.8 mm in width (William Bledsoe collection, from Panglao, Bohol Island, Philippines, from tangle nets, in 146 meters, June 1980). Type locality -Davao Gulf, Mindanao Island, Philippines, netted in 200 meters in 1980 by Filipino shell fishmen. Distribution -Known only from Davao Gulf and Bohol Strait. Etymology -'Named for Joel Greene, an avid collector and a purveyor of shells. Remarks -This species is reminiscent of the western Atlantic species Morum (Oniscidia) dennisoni (Reeve, 1842; Dance and Emerson, 1967, p. 93-94, pi. 12, figs. 5-7), but differs in details of the sculptural ornamentation and in the coloration of the aperture and parietal shield. Morum (0.) exquisitum (Adams and Reeve, 1848), a species also known only from Philippine waters (Emerson, 1977, p. 83, 84, figs. E, F, J), has a more robust shell, with stronger and more numerous axial ribs, and a purplish pink parietal shield and outer lip. Morum (0.) kurzi Petuch (1979, p. 7, figs. 10-13), recently described from the Philippine Islands, has a smaller shell with coarser sculp- ture and an orange-colored parietal shield and outer lip (fig. 7). The Sino-Japanese species, M. (0.) macandrewi (Sowerby, III, 1889; Habe, 1964, p. 67, pi. 20, fig. 4), has coarser sculpture, stronger banding, with a white parietal shield and a white outer lip bordered with numerous dark blotches on the outer labial rim. Morum (Oniscidia) macdonaldi, new species Figs. 4-6 Description- Shell somewhat pyriform, broadly shouldered, small for group, attaining 17-1- mm in length (holotype, fig. 4); spire weak- ly extended; protoconch of 3 whorls, erect and papillate; A+ postnuclear whorls cancellated, with 12 strong spiral cords, crossed by 16 promi- nent axial ridges (varices); juncture of spiral cords and varices with a blunt, weakly hooked spine, spines most conspicuous at the shoulder; intervarical pits with 6 to 10 weakly raised striae; parietal shield small, largely confined to columella wall, with outer margin raised and covered with numerous small pustules, mostly pimplelike; outer lip narrowly thickened, crenu- lated and toothed with about 10 major denticles on the inner labial surface; 3 minor denticles near anterior end of siphonal canal; anal sulcus weakly notched; siphonal canal short, gently recurved, open. Coior- Nucleus shiny, pinkish-tan; post- nuclear whorls with creamish tan base color, 4 discontinuous purplish-browTi bands on body whorl (1 band on shoulder, 2 on either side of midbody area, and 1 near the base; bands less in- terrupted on paratype with juvenile aperture (fig. 6); darkest coloration of bands on the aper- tural sides of varical spines and at base of outer lip; parietal shield poorly glazed, with white pustules; labial margin white, not blotched. Material examined -Holotype A.M.N.H. 104 THE NAUTILUS July 10, 1981 Vol. 95(3) 203713, 17.3 mm in length, 10.8 mm in width (fig. 4); Paratype A, A.M.N.H. 203714, 16.1 mm in height; 9.5 mm in width (fig. 5); Paratype B, A.M.N.H. 203715, 15.8 mm in length, 10.2 mm in width (fig. 6); Paratype C, A.M.N.H. 203716, 15.9 mm in length, 10.1 mm in width (all ex-D. J. MacDonald collection); 2 Paratypes, D. J. Mac- Donald collection. Type locality-West reef of Kwajalein Atoll, between the islands of Kwajalein and Ninni, Marshall Islands, in about 15 meters, on sandy rubble imder coral boulders, along the ocean side dropoff of the fringing reef (^es^e D. J. Mac- Donald, February 23, 1981). Distribution -Known only from the type locality. Ety7nology -Named for the collector, D. J. MacDonald. He recognized the uniqueness of this discovery and submitted specimens to Robert W. Morrison, who in turn kindly trans- mitted the material to me for study. i?emarA-s- Somewhat resembling a tiny, immature Morum (0.) macandrewi (Sowerby, III, 1889), this distinctive species is the first representative of the genus reported from the Marshall Islands. The molluscan fauna of these atolls is well known (e.g. Dietrich and Morris, 1953; Brost and Coale, 1971). The difficulties of collecting on the ocean side of the reefs and the diminutive size of the shells undoubtedly have contributed to the failure to find specimens in the past. No specimens were obtained inside the lagoon. Mr. MacDonald reports examining about a dozen specimens, including two living ones discovered at night on patches of sand near coral rubble. None of the six specimens recorded here were live- taken, but several were obtained in a well-preserved condition, as is the case of the holotype and the figured paratypes. ACKNOWLEDGMENTS I am indebted to the following collectors for their generosity in submitting specimens for study: William Bledsoe of Los Angeles, Califor- nia, Joel Greene of San Francisco, California, Robert W. Morrison of Sarasota, Florida, D. J. MacDonald of Kwajalein Atoll, and Carl C. Withrow of St. Petersburg, Florida. Virginia 0. Maes and Robert Robertson of the Academy of Natural Sciences of Philadelphia, Russell Jensen of the Delaware Museum of Natural History, and Joseph Rosewater of the U.S. Na- tional Museum of Natural History, kindly pro- vided information on material in their respec- tive institutional collections. I thank my col- leagues, Sideny S. Horenstein and William E. Old, Jr., for technical assistance. LITERATURE CITED Adams, Arthur. 1855. Descriptions of new genera and spe- cies of gasteropodous [sic] Mollusca. Proc. Zool. Soc. Londmi for 1853, 21(259):182-186 (May 16, 1855). Adams, Arthur and Lovell Reeve. 1848[-50]. Mollusca. In. A. Adams, The Zoology of the Voyage of H.M.S. Sama- rang; under the Command of Captain Sir Edward Belcher. London, p. x +87. Brost, F. B. and R. D. Coale. 1971. A Guide to Shell Col- lecting in the Kwajalein Atoll. Charles E. Tuttle Co., Rut- land, Vermont, 157 pp. Dance, S. P. and W. K. Emerson. 1967. Notes on Morum dennisoni (Reeve) and related species (Gastropoda: Ton- nacea). The Veliger 10(2):91-98. Dietrich, R. V. and P. A. Morris. 1953. Mollusks from Kwajalein. The Nautilus 67(1):13-18. Emerson, W. K. 1967. A new species of Morum from Brazil, with remarks on related species (Gastropoda: Tonnacea). The Veliger 9(3):289-292. 1968. A new species of the gastropod genus Morum from the eastern Pacific. Jour. Conchyl. 107(1): 53-57. 1977. Notes on some Indo-Pacific species of Morum (Gastropoda: Tonnacea). The Nautilus 91(3): 81-86. Habe, Tadashige. 1964. Shells of the Western Pacific in Color, 2. English ed. Hoikusha, Osaka, 233 pp. Hanley, Sylvanus. 1858. Description of a new Oniscia. Proc. Zool. Soc. London 26(142):255-256. International Commission on Zoological Nomenclature. 1975. Opinion 1040 Oniscidia Morch, 1852 (Mollusca): Placed on the Official List. Bull. Zool. Nomeri. 32(3): 139-140. Kuroda, Tokubei and Tadashige Habe, In, T. Habe. 1961. Colored Illustrations of the Shells of Japan, 2, Hoikusha, Osaka, Appendix, p. 1-41. Linne, Carl. 1767. Systema naturae per regna tria naturae. Editio duodecima. reformata, pt. 2, p. 533-1327. Melvill, J. C. 1919. Description of Morum praeclarum, sp. nov., with remarks on the Recent species of the genus. Proi: Mnlnc. Soc. London 13(3-4):69-72; Addendum, Itnd. 13(5-6): 145. Morch. 0. A. L. 1852. Calalogus conchyliorum . . . de Yoldi. Regis Daniae. Copenhagen. Fac. 1, 170 p. Petuch, E. J. 1979. Twelve new Indo-Pacific gastropods. Occ. Pap. Delaware Mus. Nat. Hist. Nemmiria no. 23, 21 p. Vol. 95(3) July 10, 1981 Powell. A. W. B. 1958. Mollusca of the Kermadec Islands. Pt. 1. Rirordx Auckland Inst, and Mus. 5(l-2):65-85, pis. 9-11. Reeve, L. A. 1842. Conchologia Systematica, or Complete System of Conchology. London, vol. 2. Roding, P. F. 1798. Musmm Btilteniariuni . . . pt. 2, Con- chylia. Hamburg, vii+109 p. Sowerby, G. B., I. 1824. The Genera of Recent and Fossil THE NAUTILUS 105-- Shells. London, vol. 1, Oniscia pi. 233. Sowerby, G. B., IH, 1889. Descriptions of fourteen new species of shells from China, Japan, and the Andaman Islands . . . Proc. Zool. Sac. London for 1888, p. 565-570. Swainson, William. 1829-33. Zoological illustrations, or figures and descriptions of new, rare, or interesting ani- mals . . ., ser. 2, vol. 3, pis. 1-136. AGE RELATIONS AND ZOOGEOGRAPHIC IMPLICATIONS OF LATE PLEISTOCENE MARINE INVERTEBRATE FAUNAS FROM TURTLE BAY, BAJA CALIFORNIA SUR, MEXICO William K. Emerson', George L. Kennedy^, John F. Wehmiller^, and Everly Keenan^ ABSTRACT Two Pleistocene marine terraces at Turtle Bay, northwestern Baja California Sur, Mexico (27.7° N. lat.) have been dated at approximately 120.000 and 95,000 years B.P. on the basis of amino-acid racemization in fossil mollusks. These ages imply a correspondence to the early and middle-to-late parts, respectively, of marine oxygen-isotope stage 5. Faunal differences between the upper {2k-27 m), 120,000-B.P. terrace and the lower (12 m). 95,000-B.P. terrace conform to the age relations and faunal-temperature aspects docum.ented previously in other localities on the Pacific coast of North America. Faunal assemblages from, these terraces contain both extralimital northern and southern species, an enigmatic situation not uncommon in East Pacific Pleistocene deposits. However, nearly 50% of the species from the upper tei'race are warm-water (subtropical and tropical) taxa, whereas only 5% are cool-water (warm teynperate) taxa. Converse- ly, the lower terrace fauna is composed of 21 % extralimital northern taxa, and. on- ly a minor (9%) southern, warm-water element. INTRODUCTION Pleistocene marine invertebrate faunules from two marine-terrace deposits at Turtle Bay*, northwestern Baja California Sur, Mexico (Figs. 1, 2), contain distinct warm- and cool- water elements (Emerson, 1980). These faunal 'Department of Invertebrates. American Museum of Natural History, New York, New York 10024 -U.S. Geological Survey, Menlo Park, California 94025 'Department of Geology, Llniversity of Delaware, Newark, Delaware 19711 ^Turtle Bay (27°41'N., 114°52'W.) is also known as Bahia Tortugas, the port of which is Bahia San Bartolome or Puer- to Bartolome. differences, in comparison with similar faunal differences known to represent discordant ages elsewhere (Kern, 1977; Kennedy, 1978; Lajoie et ai, 1979), suggest that the warmer and cooler water assemblages at Turtle Bay might also represent different ages. To test this hypoth- esis, we examined the extent of amino-acid racemization in mollusks from each assemblage, and derived estimates of both relative and ab- solute ages. We also considered the zoogeo- graphic implications of the temporally distinct assemblages (Emerson, 1980). Amino-acid racemization methods can serve as both relative and semi-quantitative tools for 106 THE NAUTILUS July 10, 1981 Vol. 95(3) 1 SinDi»go-^l ••^^^ / 3 Punti OMCinM '1 "*^ .^_ / Bah'aToaos Santos Ol > ,/ 3 PunU China — f jr A. 4 Punii CibfM-^S i '\ •30-^ CaOoColnetl-/ / K > . o '^v^. 5 C»finlu— *, c / V /\ <^^"- >S' i / N— \ +;\^ e B«hlaSanQulntin -j\ < \ z / \ ON. PuntaBala^^^::^^^ £ y ) o\ 1' c / BahladeSebasi;an Vizcaino \ \ K "1 7L«gunaO|o(l«U«br« \ ^ ' u ""--...„^^ (Scammon Lagoon) \ \ \ A) tf ^■"•^-..^^^ /' 8 lil« C«droa — y;J3 \ ^ \ V z o < n SONOflA --^^/ Punia Eugenia tl \ J /) y'^--v.,_^ (Vircamo PeninsuiaiT\^ A i( ^\ / 9 Bahlad«Bsr1olonn« \ ' itj'"*-. > 1 2 (TurtlaBey) \ ■'^ c \ i 1 \ . ^' \ , 1 \ 10 LagunadeSanlgnacIo '' I % t \ \ -25 , (San tgnacio Lagoon] \ l^ > V 1 li ' \ \ § , 1 ^ J < / 9 /' N. K.. / \ .-' ' t 1 < m 1 flT y •^^ / £ i / 11 BahiadeMagdalena < '. / / (Magdalena Bay) > \ c "~\ JIVNIS / N \ ^ -^ / 115 f \ V"--wC. f / \ k \n V-c ^ Cabo San Lucas \ \ ' 0 \ ^ FIG. 1. Index map of Baja California, Mexico, showing Pleistocene localities (numbered 1 to 11), Turtle Bay (locality 9), and geographic place names representing the modem range endpoints of some components of the Turtle Bay faunas. dating Quaternary mollusks (see Hare et aL, 1980, for recent review and references). Recent studies of Pleistocene mollusks from both the Atlantic and Pacific coasts of the United States have shown that D/L values increase with age in Pleistocene samples with known stratigraphic relations. In addition, the temperature depen- dence of amino-acid racemization has been docu- mented with D/L data from three roughly coeval (~120,000-yr.) uranium-series-dated localities over a broad latitudinal range on the Pacific coast (24° N. to 35° N.) (Wehmiller and Emer- son, 1980). The ~120,000-yr. amino-acid isochron thus generated allows interpolation of amino-acid enantiomeric ratios (D/L values) at intermediate temperatures, such as for the localities at Turtle Bay. Sebastian Vizcaino Bay iTurtle'tJ ■ '^Ir^ Bay B-3007 ^»,B-3024 (SaioSTM) Cape ^"^V^-' Tortolo I 'B-3026 i6to9M B-3048 (6 M) localed i 9 7 Km southeast of Turtle Bay Thurloe Head FIG. 2. Sketch map (not to scale) showing the approximate location offossiliferous terrace remnants in the Turtle Bay area. The fossils used herein are part of a collection made in 1956 by the late E. C. Allison from six localities in the vicinity of Turtle Bay (Fig. 2) (see "Register of Localities" for collection data). These collections are now in the University of California Museum of Paleontology (UCMP), Berkeley. Specimens for amino-acid analysis are from two of these localities, one containing a warm-water assemblage (UCMP loc. B-3024) and the other a cool-water assemblage (UCMP loc. B-3007). Locality B-3024 is on a 24 to 27-m-high terrace along the inner, bay side of Cabo Tortolo, a peninsula forming the south- west margin of Turtle Bay; locality B-3007 is on a 12 m-high terrace along the northwest margin of the bay, round its mouth. Although terrace remnants are present at several elevations around Turtle Bay (Ortlieb, 1979; Emerson, 1980), we herein refer to localities B-3024 and B-3007 as the upper and lower terraces, respec- tively. PROCEDURE We analyzed a total of 13 samples of the venerid bivalve mollusks, Saxidomus nuttalli Conrad, 1837, Chione undatella (Sowerby, Vol. 95(3) July 10, 1981 THE NAUTILUS 107 1835), and C. califomiensis (Broderip, 1835), to determine the extent of racemization of their component amino acids. Multiple analyses, in- cluding repeats of the same shell, were neces- sary to discriminate the slight differences in age expected between the two localities. Amino-acid analyses were performed according to the pro- cedures of Kvenvolden et al. (1972), Frank et al. (1977), Wehmiller et al. (1977), and Wehmiller and Emerson (1980). Capillary column gas chro- matography was performed on either NTFA- isopropyl derivatives or NTFA-( -^ )-2-butyl derivatives of the total amino-acid mixture. The NTFA-( -)- )-2-butyl derivatives were analyzed with a Perkin-Elmer Sigma 2 gas chromato- graph, using a 100-m glass capillary column coated with OV225, programmed as follows: in- crease from 115° to 140°C at 1.5°/min, 36 min isothermal; increase at 2°/min to 165°C, 150 min isothermal. Chromatographic conditions for the NTFA-isopropyl derivatives are found in Wehmiller and Emerson (1980). When both pro- cedures were used, sample extracts were split and derivatized after all the hydrolysis and desalting steps. Excellent baseline resolution for at least seven amino acids is possible by the combination of these two procedures. The enan- tiomeric ratios (D/L) reported herein represent mean values of peak-height ratios from at least two chromatograms. Table 1 lists the enantiomeric ratios of seven amino acids in the Turtle Bay samples. These data generally satisfy the criterion of reproduci- bility and are consistent, within typical analyt- ical uncertainty, with relative intergeneric and intrageneric racemization (Lajoie et al., 1980). The only significant deviations occurred in the glutamic acid data for Saxidomus from locality B-3007. In these samples, the glutamic acid D/L values were too high in comparison with the ratios of other amino acids, particularly leucine. '' DISCUSSION Enantiomeric ratios for the Turtle Bay samples (Table 1) imply a small but significant difference in age between the two sample locali- ties. Differences in enantiomeric ratios between each locality, however, are slight and fall barely outside the range of normal analytical scatter, Table 1, Amino Acid Enantiomeric (D/L) Ratios From Ciiione and Saxidomus From Turtle Bay, Baja California Sur, Mexico (UCMP localities B-3007 and B-3024) Sample Species 79-62-1 C unbatella 79-62-2 79-62-3 79-62-4 79-63-1 79-63-1 R 79-62-2 79-62-2B S. nuttalli 79-64-la 79-64- lb 79-64-2 C. califomiensis 79-64-2R 79-64-3 79-65-1 S. nuttalli 79-65-1R 79-65-2 79-65-3 .oc. LEU GLU »AL ALA PRO PHE ASP iCal. Method i-3007 ,57 .53 .50 .83 .64 .70 nd ..8 B .56 .51 .50 .87 nd .58 .76 <.8 P .56 .57 .47 .87 nd .58 .76 nd P .52 .55 .53 .91 nd .49 .75 nd P .53 .55 .53 .91 nd (.6) nd nd P 1-3007 .65 .61 .51 nd nd .61 .62 < 8 P .62 .58 .49 .97 nd .65 .59 < .& p .64 .63 .53 .94 nd .65 .69 < 8 P .63 -52 .47 .91 nd .60 .60 <.8 P .58 .63 .55 .93 nd .57 ,69 .60 .59 .58 .94 nd .59 .66 .71 .64 .61 .89 .69 .62 .59 .94 .61 .55 .61 .57 .55 .91 .63 .57 .56 70 ,76 nd .59 .70 . 1 ,0 nd .66 ,64 ■ nd ,62 .73 72 ,70 nd e-3024 .73 .62 .51 .92 .84 .75 nd .71 .63 .54 .93 nd .65 ,67 .69 .58 .51 .99 nd .66 .58 .64 .59 .45 .86 .78 .74 nd .67 .57 .48 .94 nd .60 .69 .64 .58 .50 .94 nd .59 .65 Notes for Table 1: Amino acid abbreviations: LEU GIU VAL ALA Leucine Glutamic Acid Valine Alanine PRO Proline PHE Phenylalanini ASP Aspartic Acii Kal , S Calcite nd not determined Methods: B - (t)-2-butyl derivative on OV 225 column. P - isopropyl derivative on Chirasil Val column. Samples labelled "R" represent second fragrant cut from a shell valve. Samples split for analysis by two chromatographic methods represent single fragments, the hydrolyzate of which was split after desalting for separate derivatization. Samples 79-64-la and 79-64-lb are the two valves of a single articulated specimen of Chione, especially for the Saxidomus data. Although the ratios from each locality overlap slightly, the dif- ference in mean D/L values is 2-5% for Sax- idomus and 6-10% for Chione, depending on which amino acid is compared. According to Miller and Hare (1980), these differences would be significant at the 90-95% confidence level. It might be argued, however, that the amino-acid results do not reflect any age difference, but are instead due to typical analytical scatter (in the case of Saxidomus), or species-level effects on racemization kinetics (in the case of Ckmie). Because of our accumulated observations on nu- merous samples of both species of Chione and two species of Saxidomus (Lajoie et al, 1980; unpublished data), we believe the best interpre- tation is of a real age difference. Figure 3 plots D/L leucine values against local mean annual air temperature for three uranium- series dated localities along the Pacific coast, at Cayucos, San Diego (Nestor Terrace), Califor- nia, and at Magdalena Bay, as well as D/L leu- cine values for Bird Rock Terrace at San Diego. 108 THE NAUTILUS July 10, 1981 Vol. 95(3) 1.0- .9- .8- .7- LLi -J .5- ^ ^- Q 3 .2- .1- 0- LOC: SD TB MB 1 10 12 14 16 18 20 22 24 PRESENT MEAN ANN. TEMP., "C. FIG. 3. Comparison of D/L leucine values from Turtle Bay samples mlh 120.000-yr. B.P. isochron of D/L leucine vs. present mean annual temperature (after Wehmiller and Emerson. 1980). Calibration localities, connected by solid line, are: Cayucos (C, 35.3°N. lat); Nestor Terrace CN, at San Diego. SD, 32.7° N. lat): Magdalena Bay (MB, 2J,.8°N. lat). Data for Bird Rock Terrace (BR, at SD), which is known to be younger than the Nestor Terrace (Kern. 1977), imply a leucine kinetic model age of 80.000 ±10.000 years (Wehmiller et al., 1977). The plotted D/L leucine values for Turtle Bay (TB>. 0.57 ± 0.03 for loc. B-3007 and 0.65 + 0.03 for lac. B-302It. are mean values of all data, factored to account for intergeneric differences in Chione, Protothaca, and Sax- idomus (Lajoie et al, 1980), and for differences produced by the two analytical methods used in this study (Wehmiller and Emerson, 1980:32, footnote). The present mean annual temperature at Turtle Bay is 20.9°C. (Hastings, 1961,). The leucine mjudel age for loc. B-3007 is 95.000 ±15,000 years, us- ing 120.000 years as the "calibration" age for loc. B-3021, and a slightly cooler Effective Quidernary Temperature for B-3007. The age of Bird Rock Terrace, which occurs be- low the 120,000-B.P. Nestor Terrace, is esti- mated at 80,000± 15,000 B.P. by amino-acid dating (Wehmiller et al, 1977) and from its geologic relation to the Nestor Terrace (Kern, 1977). Both the faunal characteristics and rela- tive extent of racemization of the Nestor/Bird Rock Terrace pair resemble those of the upper and lower terraces at Turtle Bay and invite com- parison along these lines. The data points plotted in Figure 3 are mean values of all the D/L leucine determinations in Chione, Protothaca, and Saxidomus from each locality. These data have been factored slightly to allow comparison of results obtained from dif- ferent genera^ and by the two analytical methods mentioned previously (see Wehmiller and Emerson, 1980:32, footnote). The Turtle Bay data are plotted at a mean an- nual air temperature of 20.9° C (Hastings, 1964). The data point for the upper terrace (loc. B-3024) lies just below the smooth 120,000-yr. (early stage 5) isochron drawn through the three uranium-series-dated calibration points. The separation between the isochron and locality B-3024 data point is analytically only marginally significant, and can not be considered as reliable evidence for an age significantly less than 120,000 B.P. because of uncertainties in their local Effective Quaternary Temperature his- tories^. For example, if the difference in the assigned temperatures of Magdalena Bay and Turtle Bay was 0.3°C greater than that used herein, the B-3024 data point would lie on the isochron. Small differences in effective-tem- perature histories create an inherent uncertain- ty in amino-acid dating, especially in cases where only small increments of time are being resolved. The data point for the lower terrace (loc. B-3007) plots well below the 120,000-yr. iso- chron and cannot be considered contemporane- ous unless unreasonably large effective-temper- ature differences are invoked. Assuming an equal effective Quaternary temperature history for both terraces (and an age of 120,000 B.P. for the upper terrace), the age estimate for the lower terrace would be approximately 85,000 ± 15,000 B.P., using the leucine kinetic model of age estimation (Wehmiller et aL, 1977). Because localities younger than 120,000 B.P. probably have had a slightly cooler (0.3-0. 5°C.) effective- temperature history (Wehmiller et aL, 1976; Wehmiller et al.. 1977: fig. 16, table 1), the age ^Protothaca and Chione are assumed to have equivalent kinetics; Saxidomus data have been converted to "equiva- \ent-Protothaca" values (Lajoie et al.. 1980). i^The Effective Quaternary Temperature (EQT) is the temperature representing the average rate constant, and in- tegrated temperature history, for a fossil sample (see Wehmiller el al. 1977; Kvenvolden et at. 1979; Wehmiller and Emerson, 1980; Wehmiller. 1981). Vol. 95(3) July 10, 1981 THE NAUTILUS 109 estimate for the lower terrace is herein revised to approximately 95,000 B.P. (see Wehmiller et ai, 1977:68, for discussion of similar tempera- ture modeling of the Bird Rock Terrace age estimate). In summary, the early and middle-to-late stage 5 amino acid age estimates for the upper and lower terraces at Turtle Bay are based on small differences in analytical results that could also be due to factors other than age. Neverthe- less, the simplest, and we believe the best, inter- pretation is of a real difference in age (within a single interglacial stage) between the two ter- race remnants at Turtle Bay (Iocs. B-3024, B-3007). Implications of an apparent difference in the age and faunal character of the terraces at Turtle Bay and elsewhere along the Pacific Coast (Kern, 1977; Kennedy, 1978) are discuss- ed below. Faunal comparisons of Turtle Bay assemblages The upper Pleistocene terrace deposits from Turtle Bay have yielded 138 species of metazoan invertebrates, mostly mollusks (Emerson, 1980). When these fossils were collected, they were believed to represent a single period of deposition. Although most of the terrace de- posits around Turtle Bay are horizontal in atti- ;ude, some are clearly deformed or faulted Mclntyre and Shelton, 1957; Minch et ai, 1976), and the differences in elevation were at- ;ributed to this post-depositional deformation. The fossiliferous terrace remnants in the vicini- :y of Turtle Bay (Fig. 2) actually represent several terrace levels: at 4.5 to 6 m (UCMP Iocs. 3-3027, B-3050, B-3048), at 6 to 9 m (loc. 3-3025), at 12 m (loc. B-3007), and at 24 to 27 m ,loc. B-3024) (elevations determined by E. C. \.llison, see Fig. 2 and Emerson, 1980). How- 'ver, Ortlieb (1979:Fig. 1) recorded terrace elevations in the Turtle Bay area at 5, 12, 20, uid 50 m. Two of the terrace localities (UCMP loc. 3-3024, B-3025) contain warm-water (sub- ropical and tropical) species and were cor- elated with marine oxygen-isotope substage 5e '^Sangamon interglaciation) (Emerson, 1980) 'n the basis of faunal comparisons with other dated assemblages (Kennedy, 1978). Four other assemblages from Turtle Bay (Iocs. B-3027, B-3050, B-3007, and B-3048) lack these warm- water species and were not assigned to any in- terglacial or isotopic stage on the basis of their faunal composition (Emerson, 1980). Emerson (1980) reported 83 positively identi- fied species (53 gastropods, 28 bivalves, 1 chiton, and 1 echinoid) from locality B-3024 and 34 taxa (16 gastropods, 17 bivalves, and 1 echi- noid) from locality B-3007 (Tables 2-5). In all, 20 species (12 gastropods and 8 bivalves), about 20% of the total number of taxa, are common to both localities. No extinct species have been recognized in these faunas. Comparison of the modern geographic ranges of the species from the upper and lower terraces (Iocs. B-3024 and B-3007, respectively) show basic differences in the zoogeographic composi- tion of each fauna. Combined, the faunas con- tain 25 tropical (Table 2), 17 subtropical (Table 3), and 8 warm-temperate (Table 4) species. The warm-water fauna of the upper terrace contains 19 gastropods and 5 bivalves that have modern northern endpoints of range south of Turtle Bay (Table 2). An additional 14 species (6 gastro- pods, 7 bivalves, and 1 chiton) occur only as far north as the Isla Cedros-Bahia de Sebastian Vizcaino area, and three other species (two gas- tropods and one bivalve) range only as far north as Bahi'a de Todos Santos in Baja California Norte (Table 3). Thus, the assemblage from the upper terrace contains distinct tropical and sub- tropical elements representing nearly one half (49%) of the fauna. On the other hand, the as- semblage from the lower terrace contains only three southern species (one gastropod, one bi- valve, and one echinoid) that do not occur today as far north as Turtle Bay (Tables 2, 3). The two mollusks are common to both localities. Table 4 lists warm-temperate species with southern endpoints of range north, or in the vicinity, of Turtle Bay. This northern element is represented by only four species (three gastro- pods, one bivalve) on the upper terrace and by seven species (two gastropods and five bivalves) from the lower terrace. Of these, two gastro- pods and one bivalve are common to both localities. The northern species from the upper 110 THE NAUTILUS July 10, 1981 Vol. 95(3) Table 2. Southern (tropical) Faunal Elements From Turtle Bay Localities B-302't and B-3007 Table 3- Southern (subtropical) Faunal Elements From Turtle Bay Localities B-3024 and B-3007 [Names in brackets for species not collected at locality B-302'i, but recorded from SDSNH 062't (=locanty B-3024; Emerson, 198O]. Species with modern northern endpoints of range that occur south of, or in the vicinity (■•') of Turtle Bay. Mollusca: Gastropoda Bulla punatulata Cancellaria oassidiformis Cantharus elegans Ceritkium maculosum Columbella major *Conus fergxisoni __ Conus perplexus IConus purpurasaens'^ [ Cypraea annettae'] [ Cypraea arabicula'^ Hormospira maculosa Nerita saabriaosta Oliva incraasata Oliva polpasta forma davisae Phyllonotus erythrostomus Strombus graoilior \_Strombus granulatusj Thais biserialis Trigonostoma goniostoma Bivalvia [ Araopsis solida ] Chione picta Ostrea angelica Semele flavesoens Trachyaardium panamense Echi nodermata : Echinoidea Eucidaris thouarsii Col lect ing Stations B-302l( B-3007 X 1 X 1 X x_ X 1 X 1 X X [Names in brackets are species not collected at locality 6-302*4, but recorded from SDSNH 062*4 ('locality B-302I4, Emerson; 1980]. Species with modern northern endpoints of range occurring on the west coast of Baja California, north of Turtle Bay in the Isla Cedros-Bahia de Sebastian Vizcaino area, unless otherwise indicated. Col lect ing Stations Mollusca; Gastropoda 6-302*4 B-3007 Acanthina lugubris 1 X - Anachis ooronata forma hannana X - Cruoibulum scutellatum X - Eupleura mupiciformis X - Macron aethiops X X Terebra armillata X - Turbo fluotuosus X - \_Vitularia salebrosa'\ X - Bi val vi a Argopeaten aircularis s.s. 1 X - [.Barbatia gradatal X - \_BaTbatia reeveana] X - Chione gnidia Dosinia ponderosa Megapitaria squalida Protothaoa grata Tellina simulans Polyplacophora [Stenoplax magdalenensis] 06^*4 Species also recorded from SDSNH loc. (Chace, 1956; Emerson, I98O, table 1). 2 Northern endpoint of range: Bahia Todos Santos. Northern endpoint of range: 2*4 km north of Bahia San Quint in. Northern endpoint of range; Cabo Colnett. Species also recorded from SDSNH loc. 062*4 (Chace, 1956; Emerson, I98O, table 1). terrace represent less than 5% of the assem- blage, in comparison with 21% for the lower ter- race assemblage. The remaining 46 species, all mollusks (Table 5), have modern ranges that overlap the latitude of Turtle Bay. Many of these species terminate their ranges to the north at Point Conception, California (41%), and to the south on the west coast of Baja California Sur (65%). Amino-acid racemization data are not avail- Vol. 95(3) July 10, 1981 THE NAUTILUS 111 Table '4. Northern (warm temperate) Fauna I Elements From Turtle Bay localities B-302'4 and B-3007 [Names in brackets for species not collected at locality B-302'(, but recorded from SDSNH 062^4 ("locality B-302'(; Emerson, 1980). Same usage in Table 5]. Species with modern southern endpoints of range that occur north of, or in the vicinity (•'■) of Turtle Bay. Col lect i ng Stat ions B-302'4 B-3007 X X 1 Mollusca: Gastropoda Cypraea spadiaea *Lottia gigantea "Olivella biplioata Bi val via *Chaoeia ovoidea "Glans oarpentepi "Milneria minima Sasddomus nuttalli *Transennella tantilla Species also recorded from SDSNH 1 oc . 062'i (Chace, 1956; Emerson, I98O, table 1). Table 5. Other Species (non-ext ral i mi ta 1 ) From Turtle Bay Localities B-302't and B-3007 Species with modern northern and southern endpoints of range occurring north and south, respectively, of Turtle Bay. Species with northern endpoints of range extending no farther north than Point Conception, California indicated by an asterisk (*) ; species with southern endpoints of range terminating on the west coast of Baja California Sur indicated by a number sign (#). Mollusca: Gastropoda If Alia carinata *ttAstraea undosa [Siipsa aali foimiaal ttCaeoum crebricinctum ttCaecum dalli ttCollisella limatula ItConus satifomiaus Col lect i ng Stations B-302') B-3007 X X 1 X X 1 X !' - X X X X - 1 X Col lect ing St 6-3024 B [Crepidula onyx"] x Cimoibulujn spinosum x *Elephantulum aarpenteri x #Fartulum ocaidentale x iFissurella volcano x *tiHaliotis fulgens x \_Hipponix antiquatus'} x iHipponix tumens x "ItNassarius tegula x "Neverita reolusiana x "ttllopinsia norxn-si "ttPseudomelatoma peniaillata x -■■•tfPteropurpura festiva x "§Serpulorbis squamigems ■-■tt[.Tegula aureotinota'] x '■'■ttTeguta eiseni x "UTegula gallina x UTrivia solandr-i x "/fTmnaatelta oatiformica Bi val vi a '"ttArrriantis oallosa x Anomia peruviana x "Chione oalifomiensis x iCorbula luteola x *Crassinella pacifioa x Cryptomya aalifomiaa x {.Diplodonta orbellus'\ x "ttOonax aalifomiaus x HEpiluoina aalifomiaa Felaniella serioata x ttUinnites giganteus "tlLepovimetis obesa x Luainisoa nuttallii x #Macoma indentata x UMaaoma nasuta Parviluaina approximata \_Penitella fitohil x Kenitella penita "#Semele deaisa x Tagelus aalifomianus x Species also recorded from SDSNH loc. 0621) (Ch?ce, 1956; Emerson, I98O, tablel). at ions -3007 X X X 112 THE NAUTILUS July 10, 1981 Vol. 95(3) able for most of the Turtle Bay assemblages, and so any temporal correlations must be made on the basis of fauna! or geomorphic evidence. E. C. Allison, who collected these fossils, be- lieved loc. B-3025 to be on a tilted remnant of the 24 to 27 m terrace represented at loc. B-3024. Locality B-3025 was previously referred (Emerson, 1980) to isotopic substage 5e, owing to the presence of four extralimital tropical and subtropical mollusks in its fauna {Conus regu- lariti, Oliva polpasta forma davisae. Thais biserialis, and Ostrea angelica). The remaining six taxa in the small fauna all have modern geo- graphic ranges that overlap the latitude of Tur- tle Bay. The presence of an extralimital south- ern element and the geologic setting suggest that localities B-3024 and B-3025 are probably coeval and referable to the warm-water phase of the Sangamon Interglaciation (Emerson, 1980). Assemblages from the remaining Turtle Bay localities -B-3027 (northwest of the bay on the outer coast), B-3050 (inner northeastern margin of the bay), and B-3048 (southeast of the bay on the outer coast) (see Fig. 2) -are dominated by species still living in the region, but include both extralimital northern and southern taxa. Extra- limital southern species present at these localities are Thais biserialis, Trachycardium panamense, and Protothaca grata, each of which occurs in loc. B-3024, and the latter two in loc. B-3007. Three northern extralimital species also occur in loc. B-3050 (Lottia gigantea, Saxidomus nuttalli, and Tresus nuttallii), two of which are present in loc. B-3024. Because of the small size of these other faunas and the presence of both extralimital northern and southern species, we hesitate to assign precise ages to them at this time. Further amino-acid racemization deter- minations on elements of these faunas would probably resolve the question of their ages. In summary, it is difficult to imagine that faunas (from Iocs. B-3024 and B-3007) with such striking differences in their zoogeographic com- position could have been deposited contem- poraneously, and the amino-acid data presented herein support their temporal difference. Although both assemblages contain both extra- limital northern and southern species, indicative of a shift in the geographic ranges of a few com- ponent species subsequent to deposition, the overall faunal composition of each assemblage reflects different hydrocHmatic conditions. Thus, nearly half (49%) of the assemblage from the upper terrace is made up of warm-water (subtropical and tropical) faunal elements, in comparison with only 9% of these elements on the lower terrace. In contrast, 21% of the taxa from the lower terrace are northern, cool- water (warm temperate) species, in comparison with only 5% of the taxa from the upper terrace (Tables 2-4). Comparison with other faunas from Baja California Sur Late Pleistocene megainvertebrate faunas from the west coast of Baja California Sur have been reported from only three areas in addition to Turtle Bay (lat. 27°4rN.) (Fig. 1): (1) Laguna Ojo de Liebre (Scammon Lagoon, lat. 27°57'N.) -24 molluscan species from "raised beaches near Scammon's Lagoon" (Jordan, 1924); (2) Laguna de San Ignacio (San Ignacio Lagoon, lat. 26°45'N.)-88 species of mollusks (Hertlein, 1934; including taxa cited previously by Jordan, 1924); and (3) Bahia de Magdalena (Magdalena Bay, lat. 24°30'N.)-442 species-group taxa, mostly mollusks (Jordan, 1936; incorporating previous records of Dall, 1918, Smith 1919, and Jordan, 1924). The Magdalena Bay fauna is the largest Pleistocene fauna described from anywhere in Baja California. No amino-acid or radiometric dates are avail- able for the faunas at Scammon Lagoon or San Ignacio Lagoon. However, at Magdalena Bay, uranium-series dates on both corals and echinoids indicate an average age of 1 16,500 ± 6,000 B.P. for Magdalena Terrace (Omura et ai. 1979). These radiometric dates suggest that Magdalena Terrace is correlative with a high- stand of sea level at approximately 125,000 to 120,000 B.P., equivalent to the early, warm- water phase of the last interglacial stage (sub- stage 5e) of the marine oxygen-isotope record (Shackleton and Opdyke, 1973). The uranium- series date on the Magdalena Terrace has been used subsequently by Wehmiller and Emerson (1980) to calibrate the southern temperature Vol. 95(3) July 10. 1981 THE NAUTILUS 113 range of the 120,000-yr. Fig. 3. isochron shown in Amino-acid racemization data suggest that the fauna from the upper terrace at Turtle Bay (loc. B-3024) and that from Magdalena Bay (CAS loc. 754 of Jordan [1936] = loc. F-6 of Omura et al. [1979]) probably were deposited contemporaneously. Faunal comparison (Table 6) of these two assemblages suggests a slightly warmer hydroclimate at Magdalena Bay, not totally unexpected because of its more southerly location (Fig. 1). Both the absolute number and the percentage of tropical and subtropical taxa are greater at Magdalena Bay than at Turtle Bay. although both sites supported similar faunas rich in these elements. Conversely, the number of warm-temperate (i.e.. extralimital northern) taxa at Turtle Bay is greater than at Magdalena Bay. Comparison of the fauna from the lower ter- race at Turtle Bay (loc. B-3007) with the noncon- temporaneous fauna at Magdalena Bay shows greater discrepancies (Table 6). Thus, although three-fourths of the non-extralimital species at Turtle Bay also occur at Magdalena Bay, only three of the seven warm-temperate taxa occur there. Moreover, two of the three tropical and subtropical species are common to both localities. Table 6. Comparison of Positively Identified Species in Turtle Bay Faunas with Those of the Magdalena Bay Faunas. (A) Present at CAS loc. 75I1 and loc. F-6 Present at Haqdalena Bay (cf. Jordan. 1936) H » % S * of (A) H ■' of (A) Loc. 6-302'i Total Species 83 = 100? 63 761 Ih SgJ Tropical 21. 29 21 87s 23 96'> Subtropical 17 20? 13 76'.. 15 88'.' Non-extral imi tal 38 1.6 » 28 73".: 33 86.. Warm temperate I4 5"; 1 25* 3 m Loc. B-3007 Total species 31. = 100? 15 1.1.-- 23 681- Tropical t subtropical 3 9i 1 33' 2 667 Non-extral imi tal 21. 70;; 13 5VJ 18 75^ Warm temperate 7 21* 1 \Vr. 3 1.3'' Comparison with more northern localities The temporal and faunal relations of the up- per and lower terraces at Turtle Bay invite com- parison with other terrace pairs on the Pacific coast. The best known of these pairs is at Point Loma in San Diego, California, where Nestor and Bird Rock Terraces occur in superposition. The upper terrace (Nestor) has been dated by uranium-series methods on corals at 121,000 + 10,000 B.P. (Ku and Kern, 1974), and the lower terrace (Bird Rock) by amino-acid methods (Wehmiller et al.. 1977) and geologic evidence (Kern, 1977) at approximately 80,000 B.P. Thus, the terraces at Point Loma can be correlated to the early and late phases of marine oxygen- isotope stage 5 and correspond to the ages ob- tained herein for the terrace pair at Turtle Bay. Although it is inappropriate to make a direct species comparison of the San Diego and Turtle Bay faunas because of the distance separating them (~600 km) and of the different deposi- tional settings, their zoogeographic relationship can be examined. The fauna of Nestor Terrace contains both extralimital northern and south- ern species, but is dominated by southern species; this observation suggests seasonal temperatures warmer than those now prevail- ing in the San Diego area (Kern, 1977). The fauna of lower and younger Bird Rock Terrace contains few (4%) extralimital northern ele- ments, but lacks extralimital southern species; this observation suggests marine temperatures lower than those of the San Diego area (Kern, 1977). The similarity of the radiometric and amino- acid age estimates for these widely separated terrace pairs (southern California and northern Baja California Sur), as well as their similar zoogeographic compositions, is strong evidence that near-shore marine waters were successive- ly warmer and cooler than those of today during the early and middle-to-late parts, respectively, of marine oxygen-isotope stage 5 (130,000- 80,000 B.P.). Provincial assignments of Turtle Bay assemblages The original usage of a single provincial 114 THE NAUTILUS July 10, 1981 Vol. 95(3) designation for a geographically prescribed area (Valentine, 1961; Addicott, 1966) must now be tempered by the recognition of more than one marine-terrace level (and associated fauna) at elevations previously believed to represent con- temporaneous deposition (Kennedy, 1978, 1979). In the San Diego, California area, for ex- ample, assemblages from late Pleistocene ter- race deposits that previously were considered coeval are now referable, on the basis of radio- metric and amino-acid age estimates, to three temporally distinct episodes of deposition (Ku and Kern, 1974; Kern, 1977; Masters and Bada, 1977; Wehmiller et aZ., 1977; Lajoie et aL, 1979; Demere, 1980; and Karrow and Bada, 1980). The recognition of several possible terrace ages that relate to highstands of sea level during dif- ferent glacial minima requires that provincial faunas be identified by their respective ages (Kennedy, 1978). Establishment of a geochro- nology that is related to the deep-sea isotopic chronology of glacial minima and maxima (Shackleton and Opdyke, 1973) facilitates the assignment of an isotopic-stage number to the modern or Pleistocene provincial name most representative of that fauna (Kennedy, 1978). Valentine (1961:393) proposed the Magdale- nan Province for late Pleistocene molluscan assemblages characterized by tropical and sub- tropical faunas at Magdalena Bay and elsewhere along the coast of Baja California Sur, the Gulf of California, and the adjacent mainland of Mex- ico. The Magdalenan Province is here restricted to faunal assemblages that are referable to the 130,000- ~120,000-B.P. highstand of the sea, correlative with the early part of marine oxy- gen-isotope stage 5 (substage 5e). The warm- water assemblages at Turtle Bay (loc. B-3024 and probably loc. B-3025) are herein assigned to the Magdalenan Province. Other warm-water faunas from along the southern Baja California coast at San Ignacio Lagoon (Hertlein, 1934) and at Scammon Lagoon (Jordan, 1924) prob- ably also can be assigned to the Magdalenan Province. However, provincial assignments based entirely on faunal inferences should be tempered by some means of absolute dating, especially if their faunas are small and contain a mixture of northern and southern species. The cooler water, middle-to-late stage 5 as- semblage at Turtle Bay (loc. B-3007) is not as readily assigned a Pleistocene provincial desig- nation because the more northerly Verdean and Cayucan Provinces also have been restricted to early stage 5 faunas (Valentine, 1980). Until more of the known localities along the Baja California coast are dated, either biochemically or radiometrically, and can be shown to repre- sent either early or late stage 5 time, provincial delineation will remain difficult. Fossil localities with faunas that still need provincial assignment include those at Cedros Island (Hertlein, 1934), and in Baja California Norte at San Quintin (Jordan, 1926), Punta Cabras (Addicott and Emerson, 1959), Punta China (Emerson, 1956), and Punta Descanso (Valentine, 1957). A fauna at Camalii has been assigned already to the Pleistocene Verdean Province by Valentine (1980). Register of Localities University of California Museum of Paleon- tology, Berkeley, California. All fossils were col- lected by E. C. Allison. For locality data of Magdalena Bay localities, see Omura et ai, (1979). UCMP loc. B-3007. Terrace deposit at an ele- vation of about 12 m, N. 30°E. of peak on south side of entrance to Turtle Bay. Collected June 18, 1956. UCMP loc. B-3024. Terrace, traceable for several hundred meters, at an elevation of 24 to 27 m, along the southwestern part of Turtle Bay in back and south of small fishing camp. Col- lected June 26, 1956. UCMP loc. B-3025. Terrace at an elevation of 6 to 9 m southeast of loc. B-3024 and possibly equivalent to the terrace at loc. B-3024, because it appears to be tilted in that direction. Collected June 26, 1956. UCMP loc. B-3027. Terrace at an elevation of 4.5 to 6 m immediately behind long sandy beach along southwestern part of peninsula northwest of Turtle Bay. Collected June 27, 1956. UCMP loc. B-3048. Terrace at an elevation of approximately 6 m that extends along the open coast adjacent to a long sand-gravel beach about Vol. 95(3) July 10, 1981 THE NAUTILUS 115 9.7 km southeast of Turtle Bay. Collected July 2, 1956. UCMP loc. B-3050. Terrace at an elevation of 4.5 to 6 m along the northeast side of Turtle Bay. Collected July 3, 1956. ACKNOWLEDGMENTS Fossils from Turtle Bay used for amino-acid analysis were kindly loaned by Joseph H. Peck, Jr., of the University of California Museum of Paleontology, Berkeley. Technical assistance was provided by William E. Old, Jr., of the American Museum of Natural History, New York. Amino-acid research at the University of Delaware, Newark, was supported by U.S. Geological Survey Grants 14-08-0001-G592 and 14-08-0001-G680. The manuscript was critically reviewed by Kenneth R. Lajoie, Leslie F. Marcus, and Louie N. Marincovich, Jr. LITERATURE CITED Addicott, W. 0. 1966. Late Pleistocene marine paleoecology and zoogeogi'aphy in central California. U.S. Geol. Surv. Prof. Paper 523-C, iii + Cl-C21 p. Addicott, W. 0. and W. K. Emerson. 1959. Late Pleistocene invertebrates from Punta Cabras. Baja California, Me.xico. Amer. Mus. Novitates. no. 1925, 33 p. Chace, E. P. 1956. Additional notes on the Pliocene and Pleistocene of the Turtle Bay area, Baja California, Mex- ico. San Diego Soc. Nat. Hist. Trans. 12(9):177-180. Dall, W. H. 1918. Pleistocene fossils of Magdalena Bay, Lower California collected by Charles Russell Orcutt. The Nautilus 32(l):23-26. Demere, T. A. 1980. A late Pleistocene molluscan fauna from San Dieguito Valley, San Diego County, California. Sari Diego Soc. Nat. Hist. Trans. 19(15):217-226. Emerson, W. K. 1956. Pleistocene invertebrates from Punta China. Baja California, Mexico, with remarks on the com- position of the Pacific Quaternary faunas. Amer. Mus. Nat. Hist. Bull. lll(4):313-342. 1980. Invertebrate faunules of late Pleistocene age, with zoogeographic implications, from Turtle Bay, Baja California Sur, Mexico. The Nautilus 94(2):67-89. Frank, H., G. J. Nicholson and E. Bayer. 1977. Rapid gas chromatographic separation of amino acid enantiomers with a novel chiral stationary phase. Jour. Cknmi. Sei. 15:174-176. Hare, P. E., T. C. Hoering and K. King, Jr. [eds.]. 1980. Biogeochemistry of Amino Acids, John Wiley & Son. New York. Hastings, J. R. 1964. Climatological data for Baja California. Univ. Arizona, Inst. Atm. Phys., Technical Reports of the Climates of Arid Regions, No. 14, p. 1-132. Hertlein, L. G. 1934. Pleistocene mollusks from the Tres Marias Islands, Cedros Island, and San Ignacio Lagoon. Mexico. So. Calif. Acad. Sci. Bull. 33(2):59-73. Jordan, E. K. 1924. Quaternary and Recent molluscan faunas of the west coast of Lower California. So. Calif. Acad. Sci. Bull. 23(5): 14,5- 156. 1926. Molluscan fauna of the Pleistocene of San Quintin Bay, Lower California. Calif. Acad, Sci. Proc. ser. 4, 15(7):241-255. 1936. The Pleistocene fauna of Magdalena Bay, Lower California. Stanford Unic. Contrib. Dept. Geol. 1(4):101-173. Karrow, P. F. and J. L. Bada. 1980. Amino acid racemization dating of Quaternary raised marine terraces in San Diego County, California. Geology 8(4):200-204. Kennedy, G. L. 1978. [MS]. Pleistocene paleoecology, zoo- geography and geochronology of marine invertebrate faunas of the Pacific Northwest Coast (San Francisco Bay to Puget Sound). Ph.D. thesis, Dept. Geol., Univ. Cahfor- nia, Davis, 824 p. Kennedy, G. L. 1979. Pleistocene marine faunal provinces of California. Appendix, p. 15, to K. R. Lajoie and others. Quaternary marine shorelines and crustal deformation, San Diego to Santa Barbara, California, pp. 3-15. In. P. L. Abbott, [ed.], (jeological e.xcursions in the southern California area (San Diego State Univ., San Diego). Kern, J. P. 1977. Origin and history of upper Pleistocene marine terraces San Diego, California. Geol. Soc. Amer. Bull. 88(11):1553-1.566. Ku, T. -L. and J. P. Kern. 1974. Uranium-series age of the upper Pleistocene Nestor Terrace, San Diego, California. Geol. Soc. Anwr. Bull. 85(11):1713-1716. Kvenvolden, K. A., E. Peterson and G. Pollock. 1972. Geo- chemistry of amino acid enantiomers: gas chromatography of their diastereoisomeric derivatives. In. Adr. Organic Geochemistry 1971. H. von Gaertner and H. Wehner [eds.], Pergamon Press, Elmsford, New York, p. 387-401. Kvenvolden, K. A., D. J. Blunt and H. E. Clifton. 1979. Amino acid racemization in Quaternary shell deposits at Willapa Bay, Washington. Geochim. Cosmochim. Acta 43(9):1.505-'l.520. Lajoie, K. R., J. P. Kern, J. F. Wehmiller, G. L. Kennedy, S. A. Mathieson, A. M. Sarna-Wojcieki, R. F. Yerkes and P. A. McCrory. 1979. Quaternary marine shorelines and crustal deformation, San Diego to Santa Barbara, Califor- nia, p. 3-15. In. P. L. Abbott, [ed.], Geological excursions in the southern California area (San Diego State Univ., San Diego). Lajoie, K. R., J. F. Wehmiller and G. L. Kennedy. 1980. Inter- and intrageneric trends in apparent racemizatiQ Series 2J,. (Revised Edition): 104 pp., 54 text figs. (20 March 1978). Oldroyd, I. 1927. The Marine Shells of the West Coast of North America. Stanford Univ. Press, vol. 2, pt. 2, 304 pp.. pis. 30-72. Radwin, G. E. and A. D'Attilio. 1976. Murex shells of the world, an illustrated guide to the Muricidae. Stanford Univ. Press, 284 pp., 32 pis., 198 figs. THE MARINE FAUNAE ZONES OF NORTH CAROLINA, WITH NEW MOLLUSCAN RECORDS Hugh J. Porter and Glenn Safrit Institute of Marine Sciences University of North Carolina Morehead City, NC 28557 ABSTRACT Northern range extensions o/Charonia variegata and Cooperella atlantica into North Carolina marine waters are reported for the first time. The occurrence in these waters of Anomalocardia auberiana, Astraea phoebia, Lima scabra, Pinc- tada imbricata and Spondylus aniericanus, previously based on few specimeyis, is further substantiated. Faunal zones are redefined in relationship to the North Carolina, marine moUuscan fauna. The purpose of paper is to clarify and substan- tiate several North Carolina range records in the molluscan literatui'e which are based on few specimens; to add several new North Carolina range records; and to discuss the relationship of these records to a reevaluation of faunal zones within North Carolina waters, an area where Cape Hatteras is considered a significant boun- dary. All records were collected within the past 14 years and unless specified, are based on adult specimens. Records catalogued in the Univer- sity of North Carolina, Institute of Marine Sciences Mollusk Collection are indicated by a UNC-IMS number, an asterisk (*) designating live-taken specimens. Anomalocardia auberiana (Orbigny, 1842). Published range: South half of Florida to Texas (Abbott, 1974). Dall (1902) records the northern range of A. brasiliayia Gmelin as Wilmington, NC. Subsequent use of North Carolina as the northern range of this species, as recorded in Porter (1974), is likely based on former account. Narchi (1972) states that the North Carolina record of A. brasiliana, in error, is for A. cuneimeiis Conrad, a synonym of A. auberiana (Orbigny), (see Abbott, 1974). DATA: Live spec- imen washed up on Bogue Banks beach, Car- teret County (34°41.4'N; 76°47.6'W). Astraea phoebia Roding, 1798. Published range: Southeast and northwest Florida to Brazil (Abbott, 1974). Menzies, et al. (1966) list the species in their North Carolina report but give no locality data. Later North Carolina range references (Porter, 1974) are probably based on the Menzies et al. report. See also Porter (1974) and Schwartz and Porter (1977) for recent North Carolina records of the species. DATA (11 specimens south of Cape Lookout- Beaufort Inlet area): Juvenile, UNC-IMS#4174 (34°17.5'N; 76°10.8'W; 46 m depth); UNC-IMS #3381 (34°16.5'N; 76°42.0'W; 91 m depth); 128 THE NAUTILUS July 10, 1981 Vol. 95(3) UNC-IMS#4035. 1-4035.2* (34°20.0'N; 76°42.0'W; 24 m depth); juvenile, UNC/IMS #4036 (34°23.0'N; 76°39.0'W; 24 m depth); UNC-IMS#6145* (34°15.6'N; 76°35.5'W; 32 m depth); UNC-IMS#6343* (South of Cape Look- out; 23-30 m depth); UNC-IMS#7105. 1-7105.4 (34°21.8'N; 76°35.0'W; 20-26 m depth). Speci- mens were found at 20-91 m depth generally in rocky or shelly substrate. North Carolina is also the northern range of a related species A. tecta americana (Gmelin, 1791) [see Porter, 1974; record based on one specimen from south of Beaufort Inlet - UNC- IMS#4039* (34°23.0'N; 76°39.0'W; 33 m depth)]. Charonia variegata (Lamarck, 1816). Publish- ed range: Southeast Florida to Brazil (Abbott, 1974); however, Merrill and Petit (1969) record a fresh juvenile fragment off Cape Romain, SC. A Scheltema (1971) larvae record off the North Carolina coast (unlisted by Scheltema but in- dicated in Figure 6) is listed by Porter (1974). DATA (Seven specimens from south to south- east of Cape Lookout, NC): juvenile, UNC- IMS#4366 (34°9.9'N; 76°10.6'W; 35 m depth); Ross specimen* (34°23.5'N; 76°35.0'W; 24 m depth); Dixon specimen (34°14.0'N; 76°35.0'W; 26-32 m depth); Safrit specimen (34°11.0'N; 76°31.0'W; 31 m depth); UNC-IMS#7106, 7107, and 7131 (34°21.8'N; 76°35.0'W; 20-26 m depth). Specimens were found at 20-35 m depth frequently in rocky or shelly substrate. No shell or living specimens were noted in 1978 by the junior author during dives on "Ten Fathom Rock" (34°21.8'N; 76°35.0'W) but a living specimen was collected in June 1978, on "210 Rock" (34°14.0'N; 76°35.0'W) during a dive organized by Dr. R. Searls; no later records have been reported. Cooperella atlantica Rehder, 1943. NEW RANGE RECORD. Published range: Southeast Florida to Brazil (Abbott, 1974). DATA (10 specimens from southeast of Cape Lookout to southeast of New River Inlet, NC): UNC-IMS (34°10.0'N; 77°04.0'W; 27 m depth); four specimens (three living), UNC-IMS#5386 (34°12.9'N; 76°13.2'W; 37 m depth); UNC- IMS#6374 (34°11.8'N; 76°36.2'W; 37 m depth); two specimens, UNC-IMS#6463* (34°12.rN; 76°35.7'W; 37 m depth); UNC-IMS#3832 (33°55.9'N; 76°31.9'W; 35 m depth); UNC-IMS* (34°17.0'N; 76°46.0'W; 20-26 m depth). This species in North Carolina waters may be re- stricted to depths between 20 and 37 m, the lati- tude restriction, 33°55.9' to 34° 17.0', related (?) to a lack of samples at above mentioned depth, north and south of these latitudes. Lima scabra (Born, 1778). Published range: South Carolina to Brazil (Abbott, 1974), though Emerson and Jacobson (1976) list North Caro- lina to West Indies. Records near Cape Look- out, NC date back to Stimpson (1860) and Coues (1871); later records, probably based on the aforementioned, are listed in Porter (1974). Jacot (1921) implies, probably correctly, that the Stimpson and Coues records are Lima inflata Lamarck (synonym of L. pellucida C. B. Adams), a species known living in the Beaufort Inlet and Cape Lookout area. DATA (four speci- mens from south of Cape Lookout to southeast of Cape Fear, NC): UNC-IMS#2704 (33°28.5'N; 77=27.5^; 26 m depth); UNC-IMS#6104*, 7132.1*, and 7132.2* (34°14.0'N; 76°35.0'W; 26-32 m depth). Living specimens were attach- ed to under surface of rocks. Many living speci- mens were seen attached under rocks on "210 Rock" June, 1978-1980 (personal communica- tion-S. Ross) and by junior author. Pinctada imbricata Roding, 1798. Published range: South Carolina to Brazil (Abbott, 1974); however, Jacot (1921) found a recent-living specimen in the vicinity of Beaufort, NC. Other authors (Porter, 1974), listing North Carolina within the range for this species, are suspected to have as their source data the Jacot report. DATA (two specimens from Cape Lookout Bight and Pine Knoll Shores Beach, NC): UNC- IMS#7870* (34°37.5'N; 76°33.3'W; beach); Rowland and Giles specimen* (34°41.7'N; 76°52.2'W; beach). The Howland and Giles specimen was attached to Sarga^sum sp. sea- weed. Specimens collected by Jacot and more recently by Ryan (UNC-IMS#7870) may also have been brought into North Carolina waters by Sargassum or other drifting objects upon which they may have set. During winter months it is believed that P. imbricata might be found Vol. 95(3) July 10, 1981 THE NAUTILUS 129 on any beach in North Carolina wherever Snr- gassum is washed ashore. Spondylus americanus Hermann, 1781. Pub- lished range: North Carolina to Brazil (Abbott, 1974); Porter (1974) lists previous North Caro- lina records and UNC-IMS holdings. DATA (15 specimens from southeast of Cape Lookout to east-southeast of Cape Fear, NC): UNC- IMS#4415* (34°18.5'N; 76°10.8'W; 46 m depth); four specimens (three recent), UNC-IMS#3400 (33°52.(yN; 76°32.0'W; 57 m depth); UNC- IMS#4417 (33°26.0'N; 77°00.9'W; 76 m depth); UNC-IMS#2596* (34°08.1'N; 76°11.4'W; 67-72 m depth); UNC-IMS#4537* (34°09.4'N; 76°08.0'W; 70-119 m depth); two specimens, UNC-IMS#5007 (34°09.6'N; 76°10.1'W; 46-57 m depth); Safrit specimen* and UNC-IMS#7130 ;34°21.8'N; 76°35.0'W; 21 m depth); UNC- [MS#7108.1*-7108.3(34°11.0'N; 76°31.0'W; 31 n depth). Specimens were found in North Caro- ina waters between 21 and 119 m depth. Recent iving specimens have been noted on nearshore ^orth Carolina shipwrecks (pers. comm. - D. ^oe). COMMENTS: Molluscan species occur- •ing within the shallow marine waters of North Carolina have been considered members of ■ither the Virginian (Boreal subprovince), Caro- inian, and/or the Caribbean Faunal Provinces Abbott, 1968). Cape Hatteras is usually con- idered to be the southern boundary of the ■^irginian and northern boundary of the Caro- inian and Caribbean faunas. Faunal overlap- ping is common. Basically, these faunal prov- ices or regions are acceptable when consider- ig most groups of marine organisms (Briggs, 974). The North Carolina marine faunas fall in- 0 the following redefined provinces: Boreal: species having reproducing popula- lons from Labrador south to North Carolina. Virginian: species having reproducing opulations north and south of North Carolina 'aters. This group may correspond to the "Tem- erate" or "Virginian" group of Bousfield (1960). efined as ranging from the Gulf of St. Law- 3nce to northern Florida and the Gulf of Mex- 0. Carolinian: species having reproducing popu- tions from Florida north to North Carolina. i.bbott, 1968, and Briggs 1974). In North Caro- lina waters, the Carolinian species may be restricted to estuarine and nearshore waters of less than 20 or 25 m depth; further north, the species live at depths from 26-156 m (Merrill et al. 1978). Caribheayi: species seldom found north of North Carolina and probably not capable of reproducing within North Carolina waters. Ma- jor populations occur offshore in deep water habitats influenced by the warm Gulf Stream (Abbott 1968 and Briggs 1974). Anomalocardia auberiana, Astraea tecta americana and Charonia mriegata are mem- bers of the Caribbean Province and not capable of sustaining North Carolina populations. As such, they are considered as accidental strays within the North Carolina fauna. Astraea phoebia, Cooperella atlantica, Lima scabra and Spondylus americanus are believed to be members of the Carolinian Province. Cooperella atlantica is widely distributed in san- dy habitats within the area sampled and have oc- curred there for several years. Astraea phoebia, L. scabra and S. americanus frequently are found in rocky offshore areas. The fauna at "210 Rock", studied intensively during recent years, is believed to be mainly self-reproducing (per- sonal communication - R. 0. Parker). LInusually cold winters in 1977 and 1978 have caused sig- nificant mortalities at this rock (pers. comm. - R. Searls); however, the 1978 to 1980 presence of large living specimens of Charonia variegata and Lima scabra indicates that these two species, at least, are capable of surviving off North Carolina at "210 Rock" even under periods of unusually cold \\inter stress. Read (1967) in his thermal tolerance study of Lima scabra from Puerto Rico, primarily concerned with upper temperature limits, lists a winter adaptation temperature of 26.2°C for the species, a temperature considerably higher than that occurring at "210 Rock". That Charonia variegata also seems capable of surviving winter temperatures as low as 6°C, may suggest that it likewise is capable of sustaining a population within North Carolina waters. ACKNOWLEDGMENTS Specimens collected by the junior author were I 130 THE NAUTILUS July 10, 1981 Vol. 95(3) taken during dives connected with ecological studies of North Carolina rock outcroppings sponsored by: Dr. Richard Searls, Duke Univer- sity, Durham, NC (grant support: Duke Univer- sity and North Carolina Board of Science and Technology) and the Atlantic Estuarine Fish- eries Center (AEFC), National Marine Fisheries Service (NMFS), Beaufort, NC (Project Leader - Mr. R. 0. Parker). Astraea specimens collected by Mr. E. Pond (UNC-IMS #4035, 4036, 4039) were from a study supported by NC Board of Science and Technology, Grant 456. Catalogued UNC-IMS specimens used in this study not col- lected by the authors were donated by: Dr. Charles E. Jenner, Department of Zoology, University of North Carolina at Chapel Hill, Chapel Hill, NC; Mr. Bill Laughinghouse, Morehead City, NC; Mr. Steve W. Ross, Depart- ment of Zoology, University of North Carolina at Chapel Hill, Chapel Hill, NC; and Dr. William J. Woods, Swansboro, NC. Thanks are given to the following individuals who loaned specimens to the authors for use in this paper: Mr. Billy Corbett, Wilson, NC (Anomalocardia auberiana); Mr. Bob Dixon, NMFS, NOAA, Beaufort, NC (Charonia varie- gata); Ms. Jean Giles, National Park Service Ranger Station, Harkers Island, NC and Ms. Patricia A. Howland, Morehead City, NC (Pinc- tada imbricata); and Dr. Edward Ryan, Biology Department, East Carolina State University, Greenville, NC (Pinctada inibricat a -\3iter donated as UNC-IMS#7870). Specimens of Cooperella atlantica in the UNC- IMS Collection were compared by the senior author with identified specimens in the molluscan collection at the Delaware Museum of Natural History. Our specimen of Charonia variegata (UNC-IMS#4366) was identified by Mr. Russell Jensen of the above institution. Acknowledged also are Dr. A. F. Chestnut (Director) and Dr. W. E. Fahy of the University of North Carolina, Institute of Marine Sciences and Dr. Arthur S. Merrill, NMFS, NOAA, Northeast Fisheries Center, Woods Hole, MA, who critically reviewed this paper. LITERATURE CITED Abbott. R. T. 1968. Seashdia of North America. A guide to field identification. Golden Press, New York. 1974. Aytwrican Seashells (second edition). Van Nostrand Reinhold Co., New York. Bousfield, E. L. 1960. Canadian Atlantic Sea Sheila. Nat. Mus. Canada, Ottawa. Briggs, J. C. 197i. Marine Zooyeography. McGraw-Hill Book Co., New York. Coues, E. 1871. Notes on the natural history of Fort Macon, N. C. and vicinity. Proc. Acad. Nat. Sci. Philadelphia 23:120-148. Dall, W. H. 1902. Synopsis of the family Veneridae and of the North American recent species. Proc. U. S. Nat. Mus. 26:335-412. Emerson, W. K. and M. K. Jacobson. 1976. The American Museum, of Natural History Guide to Shells. Land, fresh- water, and marine, from Nova Scotia to Florida. Alfred A. Knopf, New York. Jacot, A. P. 1921. Some marine molluscan shells of Beau- fort and vicinity. Jour. Elisha Mitchell Sci. Soc. 36: 129-144. Menzies, R. J., 0. H. Pilkey, B. W. Blackwelder. D. Dexter. P. Ruling and L. McCloskey. 1966. A submerged reef off North Carolina. Int. Rev. ges. Hydrobiol. 51:393-431. Merrill, A. S., R. C. Bullock and D. R. Franz. 1978. Range extension of moUusks from the middle Atlantic Bight. The Nautibis 92:34-40. and R. E. Petit. 1969. Mollusks new to South Carolina: II. The Nautilus 82:117-122. Narchi, W. 1972. Comparative study of the functional mor- phology ol Anomalocardia brasiliana (Gmelin, 1791) and Tivela mactroides (Born, 1778) (Bivalvia, Veneridae). Bull. Mar. Sci. 22:643-670. Porter, H. J. 1974. The North Carolina Marine and Estua- rine Mollusca, an Atlas of Oecurrenee. Univ. of North Carolina, Inst. Mar. Sciences, Morehead City, NC. , C. Johnson and Anne B. McCrary. 1977. Marim Invertebrates. Introduction. In: J. E. Cooper, S. S. Robin son, and J. B. Funderburg(Eds.). Endangered and Threat- ened Plants and Animals of North Carolina, N. C. State Mus. Nat. Hist., Raleigh, NC. Read, K. R. 1967. Thermal tolerance of the bivalve mollusc Lima scabra Born, in relation to environmental tempera- ture. Proc. Malac. Soc. bond. 37:233-241. Scheltema, R. S. 1971. Larval dispersal as a means of gene- tic exchange between geographically separated popula- tions of shallow-water benthic marine gastropods. Biol. Bull. 140:284-322. Schwartz. F. J. and H. J. Porter, 1977. Fishes, macroin- vertebrates, and their ecological interrelationships with a calico scallop bed off North Carolina. NOAA, Fishery Bull 75:427-446. Stimpson, W. 1860. A trip to Beaufort, North Carolina. Amer. Jour. Sci. and Arts. (Series 2) 29:442-445. Vol. 95(3) July 10, 1981 THE NAUTILUS 131 RECOLONIZATION OF REACTOR COOLING WATER SYSTEM BY THE ASIATIC CLAM CORBICULA FLUMINEA^ R. S. Harvey Savannah River Laboratory E. L du Pont de Nemours and Company Aiken, South Carolina 29801 ABSTRACT Recolonization rates for the Asiatic dam Corbicula fluminea ranged fro7n 3 0 to 5.6ynetric tons per year in cooling water basins for a nuclear production reactor at the Savannah River Plant. However, a 10-month cleaning cycle for each basin (Jlow area. 6100 m^} keeps the depth of the stlt/clam layer low. With this deaniZ Jrequmcy. CorhicnX^ are not reaching heat exchangers at sufficient size or in suffi- cient numbers to restrict flow. Data are presented on the sue/age distribution L dams recolonizing cooling water basins between cleanings. The Savannah River Plant (SRP), built and operated for the Department of Energy by E. I. du Pont de Nemours and Company, was estab- lished in 1950 to produce plutonium-239 and tritium for national defense (Harvey and Ran- dall, 1974). SRP occupies an 800-km2 area of the Atlantic Coastal Plain near Augusta, Georgia, and is bordered on the south for 35 km by the Savannah River. The Savannah River is the arincipal source of cooling water for the nuclear •eactors used to produce the plutonium and ;ritium. The Asiatic clam Corbicula fluminea was first ■eported in the Savannah River near Augusta Georgia, in 1973 (Fuller and Powell, 1973)! --abeled as a pest species by many industries, "orbicula are noted for their ability to restrict low in water supply pipes and to clog ducts and creens. The affected industries are widespread nd include water and sewage plants, power .•enerating plants, and irrigation systems (Goss nd Cain, Jr., 1975; McMahon, 1977). By 1975, ufficient numbers of Corbicula were present in ooling water from the Savannah River to clog le heat exchangers (Fig. 1) of P-Area nuclear roduction reactor, one of three (P, K, and C) at RP. Clams were also found in the K- and C- •eactor cooling water systems. he information contained in this article was developed dur- i the course of work under Contract No. AT(07-2)-l with e U. S. Department of Energy. The cooling water for P Reactor comes from two sources: the Savannah River and a cooling water reservoir, Par Pond (Fig. 2). The cooling water for K and C Reactors is pumped directly from the river through a system of pipes into large basins. Juvenile clams apparently enter the system with the river water and are trans- ported 8 to 10 km through pipes before reaching the basins. Corbicula have been recently (1981) found in Par Pond. At K and C Areas, large volumes of river water are discharged into three 32-megaliter basins (Fig. 3) where some settling occurs before the water is pumped through heat ex- FIG. 1. Heat exchanges- openings are clogged by the Asiatic Clam Corbicula fluminea. 132 THE NAUTILUS July 10, 1981 Vol. 95(3) FIG. 2. Prnduclion Areas and coaling water .soKrcf.s- on the Savannah River Plant. Vol. 95(3) July 10, 1981 THE NAUTILUS 133 1 Process 1 T Cooling T ^ Water to \ Process Cooling Water to Heat Exchangers" 105-K ?>=o Cooling Water Basins ^^^r-i^^ ^ o ?lver I IWoter Header -CX} Tie Line Header f FIG. 3. K-Area cool By-Pass Header t7ig water system. changers in the reactor area. The floor area of each basin is approximately 6100 km^. Due to in- frequent cleanings and unexpected accumula- tions of Corbicula, the silt/clam substrate levels in P-Area basins were about 90 cm deep when heat exchanger pluggage occurred. The sub- strate levels in K-Area basins in 1976 were ap- proximately 75 cm. The deposited silt and flow of river water provides suitable substrate and Qutrients for Corbicula growth and reproduc- :ion. Silt and clams must be removed at regular ntervals to prevent heat exchanger pluggage irising from high populations of clams in the msins. Current practice is to clean the basins ?very ten months. A model has been developed to determine the •growth rate of Corbicula in the cooling water )asins at SRP (Pool and Tilly, 1978); their sur- vival in chlorinated water has also been studied Tilly, 1973). The objective of this paper is to •haracterize and provide a measure of the Cor- icula population recolonizing the K-Area cool- ag water basins between cleanings (October 976-August 1977). Method At present, the clams are controlled by clean- mg the reactor basins, pump wells, and emer- gency cooling system every ten months. Each cleaning occurs during reactor shutdown and in- volves draining the basins. The walls are washed down with fire hoses and the silt on the floor is removed. The emergency cooling system is also flushed completely at this time. When the basins were cleaned, clams sus- pended in basin water were sampled with a 760-M plankton net, 0.5 m in diameter and 1.5 m long, with a digital flowmeter mounted in the mouth of the net. The net was hand-held near floor drains as water levels dropped from 1.0 to 0.7 m. The sample was examined and clams were measured with the aid of a dissecting microscope. Quantitative samples from the walls, floors, and pump wells were washed through a U.S.' Standard Number 10 sieve to collect the Cor- bicula present. Shell lengths of 100 clams from each sample were measured with a caliper across the widest part of the shell parallel to the hinge; this measurement was then used to deter- mine the approximate age of each specimen (Gardner, et al., 1976). Results and Discussion Flow was maintained on at least one of the three cooling water basins at all times. Under normal flow conditions, water is pumped from the pump wells to heat exchangers in the reac- tor area. Basins 2 and 3 were both drained on 1 September 1977, and were dry, when sampled six days later, except for small areas exposed to leakage. Basin 1 was drained on 28 September 1977, and was sampled during and immediately after draining. Basin 2, located between the other basins, contained essentially no silt and too few clams for a meaningful sample. About 50% of the floor area of Basin 3 was covered with silt up to 12.5 cm deep with an average depth of about 7.5 cm. Clam mortality, based on 5 sample areas (each 100 cm^), ranged from 20 to 80% depending on the moisture of the sub- strate. Earlier notification would have permit- ted samples from Basin 3 during draining and would have made results more comparable with those from Basin 1. Mortality was only 5% for 134 THE NAUTILUS July 10, 1981 Vol. 95(3) Corbicula collected from pump wells in Basins 2 and 3, and for those collected from Basin 1. About 40% of the floor area of Basin 1 was covered with silt up to 5.0 cm deep with an average depth of 2.5 cm. Clam concentrations on the floors of Basins 1 and 3 (Table 1) were generally comparable ex- cept for the fifth sample from Basin 3 which was taken from a large mound of clams piled up by receding water. By using mean concentrations of Corbicidalm^ and appropriate percentages oi floor area covered by silt, clam populations in Basins 1 and 3, ten months after cleaning, were estimated to be 2.7 and 10.2 million, respective- ly (calculation excluding sample 5). Size/age distribution data (Table 2) show that Corbicula in Basin 1 were smaller and younger than those in Basin 3. A higher percentage of juveniles and fewer one- and two-year old Cor- bicula in Basin 1 than in Basin 3 may be due tc TABLE 1 . Corbicula aoneentrations in K-Area cooling water basins. Number of Clams /m^ of Sample Area Basin 1 Basin 3 Sample Basin Floor Basin Floor Sept. 1977 Suction Well No. Sept. 1977 Aug. 1978 Sept. 1977 1 3002 23270 4380 11780 2 1076 11580 505 30380 3 656 7061 2130 18600 4 1431 15403 6230 - 5 430 4628 44780^ - Sample 5 was collected from a mound of clams accumulated by receding water. The sample is not representative of clam concentrations in the basin. TABLE 2. Size distribution of Corbicula in the K-Area cooling water basin. Shell Length/ Age Class (Percent of Population) 13.6 - 18.5 mm 18.6 - 28.0 rm (2 yr) (3 yr) <7. 5 mm 7.3- 13. 5 mm Location (<1 yr) (1 yr) 186-lK Basin Floor, Sept. 1977 78.3 14.9 Wateri 100.0 186-3K Basin Floor 9.4 73.9 Suction Well 17.5 48.3 K-Area ECWS CW-39 1.0 37.0 RW-1 1.0 59.0 6.8 0.0 16.7 0.0 29.2 5.0 39.0 23.0 39.0 1.0 Shell lengths are <1 mm (151 specimens) Vol. 95(3) July 10, 1981 THE NAUTILUS 135 the source of cooling water. Basins 2 and 3 are supplied from the river water header; Basin 1 is supplied from a tie line header which has a sec- tion of pipe with stagnant water. This would suggest that the juveniles might be produced or raised in the tie line. The silt substrate in the pump wells of Basins 2 and 3 generally contained higher concentra- tions of Corbicula (Table 1) than were found in basin floor samples. The reason is not known. Size/age distribution data for clams from the pump well (Table 2) are comparable to those observed for clams in Basin 3. Wall scrapings in the K-Area basins did not yield any Corbicula. Samples (lOO-cm^ areas) were collected at various depths and washed through a U.S. Standard Number 10 sieve. Corbicula larvae, generally smaller than 250 pi, were not found in the K-Area basins. Shell lengths of 151 juveniles collected from 400 kilo- liters (kL) of water during the draining of Basin 1 ranged from 380 to 1000 m (1 kL = 264.18 gallons; 1 fi = 0.001 mm). These specimens were collected in a 715-(j plankton townet as the water level dropped from l.O to 0.7 m. This col- lection represents a concentration of about 0.4 clams/kL or 12,618 clams per basin volume. An analysis of the size/age distribution data (Table 2) shows that Corbicula grow about 600 to 1100 /i/month during the first year. On this basis, the juveniles collected from Basin 1 were probably produced in late August or early September 1977, just prior to the draining of the basin. The Corbicula spawning season begins when the water temperature reaches 16 to 17°C and continues until temperature falls below this (Gardner et al., 1976), thus allowing a spawning season in the Savannah River usually from April •through November. However, the origin of these clams can only be speculated. They could have entered the basins as larvae or as juveniles by transport through distribution pipes, or they could have been produced as larvae by adult Corbicula living on the floor of Basin 1. An experiment in October 1977 estimated the transport of Corbicula from the raw water system into Basin 1. Immediately after the basin A'as drained, the walls and floor were washed A'ith fire hoses to remove all clams. The basin was refilled on 6 October 1977, and the water was allowed to stand for two hours for the clams to settle before draining for the second time. Four Carbicula juveniles with shell lengths about 0.5 mm in length were found in a 129-kL plankton townet sample (mesh 715 fj.) collected from Basin 1 as the water level dropped from 1.0 to 0.7 m. This calculates to about 0.03 clams/kL or 946 clams/basin volume. When the basin was completely drained, the basin floor contained very little silt and only a few clams near the inlet header and near the effluent drain. Six l-m^ floor samples yielded Corbicula concentrations of 0, 0, 4, 12, 2, and O/m^. One specimen was less than 1 year old, seven were about 1 year old, and ten specimens were ap- proximately 2 years old. This experiment demonstrates how quickly a clean basin can be restocked with both juveniles and sexually mature clams from the river water header. Summary The ten-month cleaning cycle is effective in preventing the buildup of silt/clam substrate in K-Area basins. The level in 1976 was about 75 cm; in both 1977 and 1978, silt/clam levels were <15 cm. Although clams are recolonizing Basins 1 and 3 at rates of 3.0 and 5.6 metric tons/year, clams apparently are not reaching the heat ex- changers at sufficient size or in sufficient numbers to restrict the cooling water flow. A higher percentage of juvenile clams in Basin 1 (78%) than in Basin 3 (9.4%) may be due to Basin 1 receiving water from the tie line header which has a section that is not routinely flushed to remove clams. LITERATURE CITED Fuller, S. L. H. and C. E. Powell. 1973. Range Extensions of Corbicula manilensis (Philippi) in the Atlantic Drain- age of the United States. The Nautilus 87(2):59. Gardner, J. A., Jr., W. R. Woodall, Jr., A. A. Staats, Jr. and J. F. Napoli. 1976. The Invasion of the Asiatic Clam Corbicula manilensis (Philippi) in the Altamaha River, Georgia. The Nautilus 90(3): 117. Goss, L. B. and C. Cain, Jr. 1975. Power Plant and Service Water System P>.)uling by Corbicula. the Asiatic Clam. In Proceedings of Biofouling Workshop, Electric Power Re- search Institute and Maryland Power Setting Program, John Hopkins University, Baltimore, Maryland, June 16-17, 1975. 136 THE NAUTILUS July 10, 1981 Vol. 95(3) Harvey, R. S. and D. Randall. 1974. Measuring the Environ- mental Effects of Thermal Discharges. DuPont Innovn- ti„n 6(1): 1. McMahon, Robert F. 1977. Shell Size - Frequency Distribu- tions of Corbicula manilensis (Philippi) from a Clam- Fouled Steam Condenser. The Nautilus 91(2):54-59. Pool, A. C. and L. J. Tilly. 1978. A Model to Determine Growth Rate of Corbicula. USERDA Report DP-MS- 77-79, E. 1 du Pont de Nemours and Company, Savannah River Laboratory, Aiken, SC. Tilly, L. J. 1973. Clam Survival in Chlorinated Water. USAEC Report DP-1398, E. I du Pont de Nemours and Company, Savannah River Laboratory, Aiken, SC. THE REPRODUCTIVE SYSTEM OF THE WESTERN ATLANTIC ANACHIS AVARA (GASTROPODA: COLUMBELLIDAE) Roy S. Houston Department of Biology Loyola Marymount University Los Angeles, California 90045 and ABSTRACT Edward B. Hatfield' Jackson Estuarine Laboratory RFD 1, Adams Point Durham, New Hampshire 03824 The reproductive system of specimens o/Anachis avara (Say, 1822) from. Bis- cayne Bay, Florida, is described from dissections and histological sections, and found similar to that of its southern counterpart, A. brasiliana. In this case it ap- pears that the reproductive systems are of little taxonomic value at the specific level. Few investigations have been made regarding the functional anatomy of reproductive systems in the Columbellidae. Marcus and Marcus (1962b) studied the genitalia of eight species from Brazil. In a later study, Marcus and Mar- cus (1964) compared the external shell charac- teristics and the genital system of Anachis pulchella (Blainville 1829) with those species previously investigated. Houston (1976) de- scribed the reproductive systems of several species from the Gulf of California. Anachis avara (Say, 1822) is a small proso- branch of the family Columbellidae reported by Radwin (1977a) to have a geographical range from the Gulf of Maine to Miami, Florida. In Brazil and Uruguay this species is replaced by A. bra^siliana (von Martens, 1897) one of the eight species studied by Marcus and Marcus (1962b). Abbott (1974) considered brasiliana to be a subspecies of avara. Recently, Radwin (1977a, 1977b) placed these species in the genus Costoanachis Sacco, 1890. However, in this ' Present address: P. 0. Box 94, Freedom, N.H. 03836. study, we treat Costoanachis as a subgenus of Anachis. It is the objective of this study to determine if there are differences in the reproductive anat- omy, which are useful in distinguishing A reac/its avara from A. brasiliana. In addition, the major anatomical and functional aspects of the genita- lia of A. avara will be discussed, in relation to other neogastropods. Methods and Materials Both sexes of Anachis avara were collected from the shallow subtidal of Biscayne Bay, Florida. Gross anatomical features of the reproductive system were determined by means of dissections of living and preserved material. In addition, stained serial sections were used to elucidate the histological details. Through the use of standard histological techniques, the animals were infiltrated with paraffin and sec- tioned at 8 microns. The sections were then stained with Weigert's Hematoxylin and Vol. 95(3) July 10, 1981 THE NAUTILUS 137 Gomori's Trichrome following the procedure of Gomori (1950). Results The Male Duct Posteriorly, both the testis (t) and digestive gland share the visceral mass. The testis is com- posed of numerous acini which are surrounded and separated from each other by a thin layer of loose connective tissue. Mature spermatozoa oc- cur within each acinus. They are arranged in an orderly fashion with their heads embedded in the acinar epithelium and their tails extending into the center of the lumen. These acini lead to acinar ducts which ulti- mately join to form the testicular duct (td) (Fig- ure lA). Anteriorly, the testicular duct runs along the columnar region of the whorls next to the digestive gland until it becomes highly con- voluted. This coiled region, now the posterior vas deferens, appears to function as a seminal vesicle (sv) for it is densely packed with sperm. The lumen is lined with low columnar epithelium which have round basal nuclei. In addition, the cytoplasm contains light blue granules which may be secretory in nature. Furthermore, this duct is approximately 2.5 mm long and attains the same diameter throughout its length. As the seminal vesicle approaches the posterior region ?rnm , IG. 1. Genitalia of Anachis avara: A- male. B- female, ■ampulla: bc-lmrsa copulatrix; cg-capsule gland; go- ynadal oiiduct; gp-ge>i>tal pore: o-ovary: om-openiitg into ■nntle cavity: p-peois; ^A-penial duct: to- renal oviduct; sv- mvinal vesicle; i-testis: td-testicnlar duct; vd-uas deferens; ■i-vestibv.le. of the mantle cavity, it straightens out for a short distance then opens into a large thin- walled ampulla (a). This structure corresponds to the seminal vesicle of Brasilian columbellids studied by Marcus and Marcus (1962b). From this sac there is communication with the mantle cavity (om) by means of a short ciliated duct. This duct is 70^ long and its entrance into the sac is guarded by a sphincter. Anteriorly the sac or ampulla leads to a thick- walled muscular ciliated duct, the anterior vas deferens (vd). This tube runs along the right body wall until it joins the penis (p). The penis, which is located just posterior to the right cephalic tentacle, is extremely long and dorso- ventrally flattened. Furthermore, it is wide at the base and then tapers to a point. The wall of this organ is composed of an outer layer of circu- lar muscle cells. Inside are two layers of longi- tudinal muscle fibers from which arise addi- tional fibers that form a latticework around the haemal sinuses. Finally, the entire structure is covered with a single layer of ciliated squamous cells. The penial duct (pd) is centrally located and appears as a convoluted tube which opens at the tip of the penis. Histologically the penis can be divided into two regions. At the base it is lined with glandular cells interspersed with ciliated tall columnar cells. The basal round nuclei of the gland cells are highly basophilic and have two nucleoli. The ciliated cells, in turn, have oval nuclei which are centrally located. Anteriorly, the lumen of the penial duct is lined entirely by secretory epithelium. As in other col- umbellids (Marcus and Marcus, 1962b; Houston, 1976), the tip of the penis is tucked in a pouch in the posterior mantle wall. The Female Duct The bright yellow ovary (o) lies along the outer side of the visceral mass and is separated from the digestive gland by a thin layer of connective tissue. In addition, there is a tenuous layer of connective tissue surrounding the ovary itself. As in the testis of the male, the ovary is com- posed of numerous acini which collectively fun- nel into the gonadal oviduct (go) (Figure IB). Several cell types comprise the acinar epithe- 138 THE NAUTILUS July lU, 1981 Vol. 95(3) Hum. These include low columnar cells, secre- tory cells, primoidal germ cells and developing oocytes. Within the acinar lumina are oocytes that are attached to the epithelium by a pedun- cle. Also, there are large numbers of oval secre- tory droplets that stain bright red with Gomori's. The short thin-walled gonadal oviduct is lined with nonciliated low columnar epithelium and in mature females it is packed with oocytes. As this tube leaves the visceral mass it becomes ciliated and becomes the renal oviduct (ro). Here it straightens out and runs anteriorly along the right side of the body wall, just ventral to the nephridium and dorsal to the pericardial cavity. Anterior to the pericardial ca\aty the oviduct enters the posterioventral region of the large capsule gland (eg). In cross section this organ has a lumen which appears as a dorsoventral slit that divides it into right and left lobes. The lumen is lined with ciliated, tall, columnar epithelium interspersed by ducts arising from clusters of subepithelial gland cells. It is interesting to note that two sub- epithelial cell types, each with their respective staining properties, occur within the gland. The posterior one-fourth of the gland is com- posed mainly of polygonal cells with small round centrally located nuclei. Moreover, the cyto- plasm stains bluish-gi-een with Gomori's. The rest of the capsule gland is made up of elongated clusters of teardrop-shaped cells that stain deep red. In addition, within the lumen are masses of secretory droplets of the same color. Anteriorly, the lumen of the capsule gland is continuous with a large deeply folded vestibule (ve). It is rather thin-walled and lined with ciliated, low, columnar epithelium. Ventral to and communicating with the vestibule is the highly muscular bursa copulatrix (be). This organ is lined with ciliated, low, columnar epithelium like that of the vestibule, except the cilia are shorter and not as numerous. The vesti- bule and bursa copulatrix both join anteriorly in the form of a short ciliated vagina which ter- minates at the genital pore (gp). DISCUSSION As far as one is able to determine, the reproductive system of Anachis avara is like that of A. hrasiliana as described by Marcus and Marcus (1962b). It is therefore apparent that, in this case, the reproductive system is of little tax- onomic value at the specific level. Differences in reproductive anatomy, do occur among higher categories. Marcus and Marcus (1962b) concluded there are two morphological divisions among the Co- lumbellidae, based on their reproductive systems. One group contains species in which the males have a seminal vesicle and no prostate gland; and females that have an albumin gland and bursa copulatrix. The other group contains species in which males do not have a separate seminal vesicle but have a prostate gland. More- over, the females lack an albumin gland and bursa copulatrix, but they have a gonopericar- dial connection. In following this scheme, Ana- chis avara and A. hrasiliana would belong to the former group. It is worth noting that Anachis avara and the columbellids studied by Houston (1976) appear to have generalized reproductive systems with specific regions performing more than one func- tion. Thus, compartmentalization is not to the degree as in other neogastropod groups. These include: the Muricidae, Nassariidae and Buccin- idae studied by Fretter (1941), and the Turridae examined by E. H. Smith (1967). In these groups the separate organs each appear to assume one function. In male columbellids the coiled posterior vas deferens appears to function both as a seminal vesicle and for resorption of sperm. This condi- tion also occurs in those species that appear to have a separate seminal vesicle. Furthermore, the penis probably has a dual function. In addi- tion to being an intromittent organ, the pres- ence of glandular tissue indicates it may assume a prostatic function. The bursa copulatrix in females receives the penis during copulation (Houston, 1976). Moreover, it functions as a depository for spermatozoa, although no sperm were present in females of Anachis avara. Observations by Marcus and Marcus (1962b) in- dicate that in some species of columbellids, the bursa is divided into two sacs. One sac serves as Vol. 95(3) July 10, 1981 THE NAUTILUS 139 a site for sperm ingestion, while the other is ased for storage. The albumin gland oiAnachis avara and other solumbellids is not externally separated from the capsule gland, but occupies the posterior region of the latter. This also appears to be the :ase for some species of olivids (Marcus and Marcus, 1959). This arrangement differs from ather families of neogastropods where a short iuct separates the two glands. Some of these families are: Muricidae, Nassariidae and the Buccinidae (Fretter, 1941), the Terebridae (Mar- cus and Marcus, 1962a), and the Turridae (E. H. Smith, 1967). In addition. Ponder (1970) found ^his to be true for the volute, Alcithoe arabica Gmelin, 1791). Also, a later study by Ponder 1972), showed this to be the case for the Mitri- lae. More recently, Fretter (1976) indicated ;hat a deep constriction separates the capsule md albumin glands in the marginellid, Vol- mrina taeniolata Morch, 1860. Therefore, it appears that two major morpho- ogical types of genital systems occur through- out the neogastropods. One specialized type vith high compartmentalization and numerous iccessory organs, each apparently performing a :)articular function; and a second generalized ype with low compartmentalization and fewer iccessory structures which assume multiple unctions. Whether one type is more advanced han the other is difficult to determine. Recently, Radwin (1977a) mentioned that the ]olumbellidae exhibit a high degi'ee of adaptive adiation in shell morphology. Since they have nvaded numerous habitats, possibly they would lave evolved specialized organ systems to adapt 0 these habitats. This does not appear to be the ase in their reproductive anatomy. On the ther hand, since the Columbellidae originated uring the Eocene and radiated as recently as he Miocene (Radwin, Op. cit.). it is possible lere has not been enough time for specialized ystems to evolve. If there was ample time for pecializations to occur, they could possibly have een lost. In any case much work is needed on le functional and ecological interrelationships f reproductive systems. ACKNOWLEDGMENTS I am most grateful to the late George Radwin for his invaluable criticism of the manuscript. In addition, thanks are extended to Dr. Evelene Marcus for her encouragement during this study. LITERATURE CITED Abbott, R. Tucker. 1974. American Seashells. Van Nostrand Reinhold, N.Y. 663 pp. Fretter, Vera. 1941. The genital ducts of some British steno- glossan prosobranchs. Joum. Mar. Biol. Assoc. U.K. 25: 173-211. 1976. The anatomy and feeding of the volutacean prosobranch Volvarina taeniolata Morch, Joum. of Mol- luscan Studies 42(3):327-336. Gomori, G. 1950. Gomori's one step trichrome stain. Aracr. Joum. Cliyxical Path. 20:661-664. Houston, Roy S. 1976. The structure and function of neo- gastropod reproductive systems: with special reference to Columbella fu.scata Sowerby, 1832. The Veliyer 19(1): 27-47. Marcus, Ernst and Eveline du Bois-Reymond Marcus. 1959: Studies on "Olividae." Bol. Fac. Filos. Cien. Univ. Sao Paulo. Zool. 22:99-188. 1960. On Haatula cinerea. Bol. Fac. Filos Cien. U)iiv. Sao Paulo. Zool. 23:2.5-66. 1962a. On Leucozonia nassa. Bol. Fat. Filos. Cien. Univ. Sao Paulo. Zool. 24:11-30. 1962b. Studies on Columbellidae. Bol. Fac. Filos. Cien. Sao Paulo. Zool. 24:355-402. 1964. On the dove-shell Anachis pulchella (Blain- ville). Anais da Academia Brasileira de ciencias 36(3): 359-366. Ponder, Winston E. 1970. The morphology of Alcithoe ara- bica (Gastropoda: Volutidae). Malacol. Rec. 3:127-165. 1972. The moqjhology of some mitriform gas- tropods with special reference to their alimentary and reproductive systems (Neogastropoda). Malacologia 11(2): 295-342. Radwin, George E. 1968. A taxonomic revision of the family Columbellidae (mollusca: Gastropoda) in the western Atlantic exclusive of the genus .Astryis. Ph.D. disserta- tion. The George Washington University. 237 pp.. 18 pis. 1977a. The family Columbellidae in the western Atlantic. The Veliger 19(4):403-417. 1977b. The family Columbellidae in the western Atlantic. Part Ila. • The Pyreninae. The Veliger. 20(2): 119-1.33. Smith, Edmund H. 1967. The reproductive system of the British Turridae (Gastropoda: Toxoglossa). The Veliger 10(2):176-187. 140 THE NAUTILUS July 10, 1981 Vol. 95(3) GROWTH RATE DETERMINATIONS OF ACHATINELLA LILA, A HAWAIIAN TREE SNAIL Robert M. Severns^ Natural Sciences Division Hilo College Hilo, Hawaii 96720 Hawaiian tree snails of the family Achatinel- lidae are described by Pilsbry, et al. (1912- 1914). The species studied in this paper is Achatinella lila, the habitat of which is the sum- mit area of the Koolau mountains on the Island of Oahu. Little is known about the biology of these snails, therefore this study was under- taken to determine their growth rates. Materials and Methods The altitudes of the colonies range from 2,500 feet to 2,800 feet. The colonies were all located on ohia trees (Metrosiderns polymorphus) and the surrounding low shrubs and vines. Speci- mens were taken from three colonies, each of which was characterized by a distinctive overall color: brown, yellow, or green. All of the snails were banded with either yellow or brown. A total of 56 animals was collected -20 from the predominantly yellow colony, eight from the predominantly green colony, and 28 from the predominantly brown colony. The green and the yellow colonies were from the same immediate area and altitude, the brown from a slightly lower elevation. Because A. lila had not been kept in captivity successfully before, some details of the means of doing so are presented here. The collected snails were reared in cages which were 30x 18 inches on the base and 20 inches high, and made of screen on a pine frame. Three cages were con- structed to permit isolation of the individual col- onies so that no cross-breeding among colonies could occur. Because the cages were kept at a high humidity, there was a possibility that disease-causing bacterial colonies might form. To avoid this, the cages were placed in a slight draft and partial sunlight. The snails feed 'Present address: 2535 Alaula Way, Honolulu, Hawaii 96822. naturally on algae and fungus species growing on the surface of smooth-leafed plants. As per- manent substrate for the snails, Hawaiian bird nest ferns (Asplenium nidum) were kept potted in the cages. The ferns required minimal sun- light and provided a large smooth leaf surface for grazing snails. The snails do not eat the ferns. The snails were fed a mixture of lettuce and dried milk. By blending the lettuce leaf and the dried milk with water, a paste that could be lap- ped up by the snails from the surface of the substrate plants was made. This mixture was marginally acceptable by two of the varieties, while the third, the green variety, seemed to do well. All three varieties formed a growth scar while adjusting to the artificial nutrient mixture. This scar is a convenient mark with which to measure growth. Two scars were present on the shell at the end of the first month after collection. The first scar was formed after birth and marked the end of the nuclear whorl. The other scar was formed as a result of the nutritional changes described above. Several snails were born to the colonies during the initial period of captivity, and these shells showed none of the scarring due to the artificial food. The artificial food was replaced eventually by natural food (fungus and algae found on the bark and leaf surfaces of forest trees) to insure the life of the snails born in captivity and to allow growth to continue at as near normal rate as possible. The snails were fed in captivity and observed for several months. Growth measurements were taken on a total of 32 shells. Six of these were born in captivity and placed in individual size classes to the near- est 0.5 mm. The rest were grouped in 1.0 mm size classes, beginning at 11.0 mm (see Table I). Growth was measured along the suture (Fig- Vol. 95(3) July 10, 1981 Table I . THE NAUTILUS 141 Shell Sa:e Suture Growth Average suture Number of Suture Growth apex to base per sire class growth per size days of rate per day (iron) . (mm) . class (mm) . observat ion (mm) . 03.0 0.34S 03. S 1.4 04. S 2.2 05.0 2.3 07.0 1.8 08.0 2.1 11.0 3.0 l.b 4.6 12.0 3.0 2.5 3.0 1.0 9.5 13.0 2.5 3.0 1.5 2.1 2.0 11.1 14.0 2.0 2.0 1.5 1.5 1.8 2.0 1.0 11 .8 15.0 1.6 1.5 1.7 1.6 6.4 I6.n 2.0 17.0 1.2 2.0 3.2 2.3 2.4 1.7 1.6 1.6 4 20 39 47 52 72 81 81 81 81 81 81 0.086 0.070 0.056 0.049 0.035 0.029 0.028 0.029 0.027 0.021 0.020 0.025 0.020 'Bom in captivity. ure 1) of the shell, beginning at the scar formed from change in diet when the animals were taken into captivity. A thin piece of thread was used to measure the suture growth. Calipers were used to measure the overall length of the shell. An average of growth rate for each size class was calculated, and this was then divided by the number of days since scarring had occur- red to give an estimate of daily growth rate. This measurement was compared with the total length of the shell from apex to base. Figure 2 shows the relationship of these two measure- ments. The procedure was repeated with ani- mals which had been born in captivity and whose shells showed no scarring. The average growth rates of the latter series of snails also were com- 142 THE NAUTILUS July 10, 1981 Vol. 95(3) FIG. 1. The ahell measurements used in the paper: A, the apex of the shell. B, the base of the shell. G, the growth along the body whorl of the shell. L, the length of the shell from apex to base, and S, the scar formed by the change in nutrition from the natural food to the artificial food. pared with the length of the shells determined from apex to base. This series of young in- dividuals provided the growth rate data for the beginning of the curve. Results Table I presents growth data from the snails. The first column lists the different size classes into which the snails were put according to their shell length (Figure 1). The second column shows the individual growth measurements of the snails in each size class. These measure- ments were averaged in those size classes with more than one individual (third column). The fourth column shows the growth period in num- ber of days. The growth, or average growth, of the snails during the observed growth period was then divided by the number of day of obser- vation giving a value in millimeters which represents the average growth per day of the shells. This latter value was plotted against shell length to obtain the curve (Figure 2), which shows changes in the growth rate as the snail matures. This growth rate curve shows a rapid decrease in growth rate as the shell length increases. The shell length at which the growth rate begins to level off is approximately 9 mm. The length of GROWTH RATES OF ACHATINELLA LILA (Pilsbry) .09 1 .08 . .07 a — .06 ° .05 g .04 .01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Length, aoex to base, (mm) FIG. 2. Growth rates 0/ Achatinella \\]a. (Pilsbry). Vol. 95(3) July 10, 1981 THE NAUTILUS 143 the shell eventually almost doubles to 17 mm but with a much slower growth rate. The smaller and younger snails grow much faster than the larger snails. Three-millimeter shells, which is the size at birth, have a growth rate of .086 mm/day. At 5 mm the daily growth rate has declined to .049 mm/day and at 8 mm to .029 mm/day. The growth rate then decreases from .028 mm/days to .020 mm/days for shells 11 mm to 17 mm re- spectively (Table I). DISCUSSION With the data collected and calculated, it became clear that age approximations for each shell class could be figured. Table II follows the progression of data from the size class to the age in days of the shell at that size class. In column 1 the size classes of shells, meas- ured apex to base, are listed. Choosing one of these classes, 15 mm, the suture of the shell was measured from the end of the nuclear whorl around the whorls to the end of the body whorl. This is shown in column 2 as 53 mm. Next, the suture of the preceding size class, 14 mm, was measured and subtracted from the length of the suture of the shell of the class of 15 mm shells. Thus an increase of 4 mm in suture length is then listed in column 3. The next step involves utilizing the data from the last column of Table I, the daily growth rate of the shell along its suture. The daily growth rates of the preceding class, 14 mm, and of the 15 mm size class, .021 mm and .020 mm respectively, were averaged to obtain .021 mm, representing the growth rate from one class to the next. Finally, in column six the number of days to advance from one class to another was figured. This was obtained by divid- ing the suture length difference of column 3, 4 mm, by the average growth rate between size classes, .021 mm/day. The final column is the ac- cumulated number of days from birth of the snail to the size class being observed; class 15 mm is 1,404 days old or 3.85 years old. It can be seen from the data, then, that the oldest and largest of the snails studied is 17 mm in length, and has reached an estimation age of 5.27 years. This suggests that the life span of the snails can be five years. ACKNOWLEDGMENTS I would like to thank Mr. Richard Davis of Kaneohe for supplying A. lila. Dr. Yoshio Ron- do of the Bishop Museum for his kind advice on raising the snails, Dr. James Rutherford of the U. of Hawaii, Hilo for his encouragement, and [All measurements in mm unless indicated.) Increase in Observed suture Averag e daily No. of days Total days Shell length Total suture suture length growth rates suture growth rates between each for each (size cl ass) . length. per class per day. between classes. si:e c ass . group. 7mm 15mm --- .055miii -_. 8 18 Smm .029 .032I1U11 72 days — 9 23 5 --- .02&* 172* 244 days 10 29 6 --- .028* 214' 458 11 33 4 .028 .028* 143 601 12 39 6 .029 .028 214 815 13 42 3 .027 .028 107 922 14 49 7 .021 .024 292 1214 15 S3 4 .020 .021 190 1404 16 60 7 .025 .023 304 1708 17 65 S .020 .023 217 1925 5.27 years 565/1925 days 144 THE NAUTILUS July 10, 1981 Vol. 95(3) especially to Dr. H. F. Little of the U. of Hawaii, Hilo for his editorial assistance. Special thanks go also to Mrs. La Vanda War- ren secretary of the Natural Sciences Division at t-he U of Hawaii, Hilo for her help in typing and other secretarial skills during the project. LITERATURE CITED Pilsbry, Henry A. and Cooke, C. Montague. 1912-1914. Achalinella'lila. Manual ofConcMogy 22:139-140. AN ELECTROPHORETIC AND MORPHOLOGICAL SURVEY OF BUSYCON AN ELECiRUPHUK^^^^^ ^^ W ASS AW SOUND, GEORGIA Amy Lyn Edwards and Celeste Marie Humphrey Skidaway Institute of Oceanography University of Georgia P.O. Box 13687 Savannah, Georgia 31406 ABSTRACT Sixty-seven specmiens of right-handed knobbed whelks _ collected m Wassaw Sound Georgia were examined for genetic and morphological vartatwrt m order toZrmiJths validity of the ta^a Busycon carica (Gmehn, 1 791) and Busycon eliceans (Montfort, 1810). Starch gel ^^^^ff^^^^^^^^^.^V^VpG^^ ^sterns; of these, six were used for data collection: SOD LAP, MDH, PGI,and 6.PGD They were all found to be moncmorphic. Four shell characters, tumidity knobhiness, aperture coloration, and the ratio of aperture lerujth to overall shell length were also examined. No assocmtion between these characters wo.s found and the sample was normally distributed. Only 3U% oj tke specirnens could be classified as belonging to B. carica or B. eliceans exclusively Therefore from thts electrophoretic and morphological evidence, we determined the sampk to have been taken from a single population o/B. carica and use of the taxon eliceans in this locale is unnecessary. The knobbed whelk, Busycon carica (Gmelin, 1791), is a large (125 to 225 mm) carnivorous gastropod common in estuaries from Cape Cod, Massachusetts, to Cape Canaveral, Florida (Ab- bott, 1974). The name Busycon elicean.^ (Mont- fort,' 1810) refers to a similar form commonly found in the southern part of the range of B. carica, from North Carolina to Cape Canaveral (Pulley, 1959). Bus-ycon carica and Busycon eli- ceans were classified by HolUster (1958) as a pair of sympatric species, and later reclassification placed the taxon B. eliceans as a subspecies of B. carica (Abbott, 1974). The adult forms of B. eliceans have previously been separated from B. carica on the basis of three morphological characters: presence of tumid ridge, prominent spines as opposed to low tubercles, white aperture coloration with yellow to brown suffusions as opposed to the orange aperture color in B. carica. In this paper all spines, knobs, and tubercles are referred to as degrees of knobbiness. Both described forms of the knobbed whelks are found in Wassaw Sound, Georgia. We exa- mined individuals from this area in order to determine their morphological and genetic variation and to see if separation of these in- dividuals into populations of B. carica andB. eli- ceans is applicable. Protein electrophoresis was employed to determine genetic differences be- Vol. 95(3) July 10, 1981 THE NAUTILUS 145 tween individuals for comparison with their morphological characteristics. Electrophoresis has been successfully used to distinguish closely related molluscan taxa (Chambers, 1978; Skibin- ski et at, 1977). The morphological traits ap- plied are those typically used by malacologists for species distinction. The niche, historical age, habitat and abundance of the animal led us to believe that electrophoretic techniques might detect considerable genetic variation. Large differences in shell form, coloration and sculpture exist among local populations, members within a single population and even in single individuals (Pulley, 1959; Stanley, 1979). Busycon is a wholly North Atlantic genus that has flourished in this region since the lower Miocene epoch (Hollister, 1958). Busycon are found in abundance from intertidal flats where their prey, oysters (Crassostrea virginica) and clams (Merceyiaria mercenaria) are numerous to approximately the 26 fathom contour offshore (Walker, in prep.). The genus seems to be made up of localized populations of slow-growing long- lived animals, and gene flow between different populations could be slow or even negligible (Pulley, 1959). Individuals are continually migrating between adjacent intertidal flats as a result of prey availability and on and offshore seasonally (Walker et ai, 1980). The estuarine habitat is not homogeneous in structure or in physical, chemical or biotic char- acteristics. Fluctuations of salinity, turbidity, water depth and temperature greater than those in the open sea are encountered (Vern- berg, 1972). Considerable controversy exists concerning the relationship between environ- mental stability and genetic variability. Based on theoretical argument, Valentine (1976) and Levins (1968) conclude that unstable environ- ments should be inhabited by organisms having higher genetic variability than organisms in- habiting stable environments. Levinton (1973) contributed experimental support to these hypotheses by demonstrating that, for different species of bivalve molluscs, varying and hetero- geneous environments did support species that were more polymorphic than those in non-vary- ing, geologically permanent environments. Lewontin (1958) demonstrated a loss of chromo- somal polymorphism in a population of Droso- phila pseudoobscura raised for many genera- tions in a constant environment and concluded that heterogeneous environments retard the loss of genetic polymorphism. Increased hetero- zygosity has also been correlated with increased benthic ecosystem diversity and with the stabil- ity of trophic resources (Selander, 1976; Valen- tine, 1976; Ayala and Valentine, 1977). Busycon, being a geologically old genus, living as it does in a temporally heterogeneous estuarine envi- ronment and experiencing spatial heterogeneity through its migratory behavior, appears to fit all the criteria necessary for the maintenance of electrophoretically and morphologically poly- morphic populations. Methods and Materials All specimens of Busycon were collected from Wassaw Sound, Georgia, in April, 1980 and kept frozen until used. Tissue samples were dissected from partially thawed specimens, ground and then run on starch gels. Morphological measure- ments taken for comparison with electrophore- tic findings were: overall length, aperture length, width, presence or absence of a tumidity across the back of the siphonal canal, direction of knobs on the whorls, extent of knobbiness, and color of the aperture. Measurements of shell width, overall length and aperture length were taken using metric calipers. Presence or absence of a tumidity (Fig. 1) and direction of FIG. 1. TTie presence (A) or absence (B) of a tumidity (a) across the back of the siphonal canal 0/ Busycon. I 146 THE NAUTILUS July 10, 1981 Vol. 95(3) knobs on the shoulder of the whorls (Fig. 2) were recorded. Color hues were determined by eye according to predetermined standards. Examin- ation of radula dentition was made. The Hunter-Markert zymogram technique combines electrophoresis with histochemical staining methods (Brewer, 1970). The electro- phoretic frequencies observed were converted to allelic frequencies for genetic inferences. The enzymes studied by this method were chosen by the availability of appropriate staining tech- niques and not with regard to the functions they specify. Horizontal starch gel electrophoresis was used following the procedure of Schaal and Anderson (1974). Ground tissue samples absorb- ed on 3 by 6 mm filter paper wicks were set in the gel and 55 ma currents were passed across the gel by a model IP-2717 Heathkit power sup- ply for five hours. Initial samples of liver, kidney, heart, and FIG. 2. Direction oj'hwbs on the shoulders of the whorLs. A. Jorwardly directed, B. recurvetl spines. radula retractor muscles were run on starch gels using six different buffer systems at vary- ing pH regions. These gels were stained for 23 enzyme systems. Lithium Hydroxide, Tris-HCl and JRP buffer systems (John Avise, personal communication), Dehydrogenase and Tris- citrate buffer systems (Schaal and Anderson, 1974), and Poulik Discontinuous buffer system (Poulik, 1957) were examined in conjunction with the following stains: Isocitrate Dehydro- genase, Lactate Dehydrogenase, Malate Dehy- drogenase (MDH), 6-Phosphogluconate Dehy- drogenase (6-PGDH), Glucose-6-Phosphate De- hydrogenase, Alcohol Dehydrogenase, Xanthine Dehydrogenase, a-Glucose Phosphate Dehydro- genase, Sorbital Dehydrogenase, Phosphoglu- cose Isomerase (PGI), Phosphoglucomutase (PGM), Glutamate Oxaloacetate Transaminase, Leucyl Amino Peptidase (LAP), Hexokinase, Nucleoside Phosphoralase, Creatine Kinase, Peptidase, Alkaline Phosphatase, Acid Phos- photase. Adenylate Kinase, Esterase o-Naph- thylacetate. Superoxide Dismutase (SOD), Malic Enzyme and General Protein (Schaal and An- derson, 1974; John Avise, personal communi- cation). The systems that produced the most clearly defined bands in the initial experiments, were chosen for data analysis. SOD, LAP and MDH stains were used in conjunction with the Tris-citrate buffer system, PGM and 6-PGDH were used with the JRP buffer system, and PGI was used with the Dehydrogenase buffer system. Results A summary of the morphological observations shows that of the 67 specimens examined, 64 were females (determined by lack of penis and presence of enlarged nidamental glands), 34 possessed recurved spines, 14 had both recurved spines and spines directed forward, and 19 had all forward directed spines. Thirty shells dis- played tumid ridges and 37 lacked them. There were 20 pale yellow, 23 yellow, 21 orange and three red apertures observed. The denticulation on the rachidian varied from four to eight while the laterals all had two large cusps on the marginal and central ends separated by two, three or four small denticles. Other workers Vol. 95(3) July 10, 1981 THE NAUTILUS 147 have found varying male to female ratios for these snails 1:11 (Walker, in prep.), 1:1, 1:2, 3:1 and 2:1 (Magalhaes, 1943). Contingency Chi-square tests were used to determine independence of the morphological traits; direction of knobs, presence of tumidity, and aperture coloration, while "goodness of fit" tests were used to ascertain normality of the population (Bhattacharyya and Johnson, 1977; Mendenhall, 1968). There is considerable varia- tion in the size and degree of knobbiness (Hollis- ter, 1958; Magalhaes, 1943) leaving these char- acteristics undiagnostic. Direction of knobs was determined to be independent of both the pres- ence of tumidity, and aperture coloration at the 0.05 confidence level: knobs/tumidity, x^ = 0.71, d.f. = 2 (Table 1); knobs/aperture coloration, x^ = 7.66, d.f. = 6 (Table 2). Tumidity and aper- ture coloration were not shown to be occurring independently at the 0.05 confidence level; x^ = 11.71, d.f. = 3 (Table 3). Additional testing of these data by both Cramer's contingency coeffi- cient and Pearson's coefficient of mean square contingency indicated no strong associations between variables and leaves the above men- TABLE 1. Contingency Table using the Chi-square "good- ness of fit" test for the Null Hypothesis that the two variables. Tumidity and Direction of Knobbation, are independent of each other. Expected frequencies are listed in parenthesis next to observed frequencies, k' = 0.71, d.f. = 2, at 0.05 con- fidence level. TABLE 3. Contingency Table using the Chi-square "good- ness of fit" test for the Null Hypothesis that the two variables. Tumidity and Aperture Coloration, are independent of each other. Expected frequencies are listed in parenthesis next to observed frequencies, x' = 11.71. d.f. = 3, at 0.05 confidence level. Tumidity Present Absent Totals Coloration Red 2 ( 1.34) 1 ( 1.66) 3 Orange 10 ( 9.40) 11 (11.60) 21 Yellow 15 (10.30) 8(12.70) 23 Pale Yellow 3 ( 8.96) 17(11.04) 20 Totals 30 37 67 tioned dependence uninterpretable. These values were 0.17 and 0.39 respectively. The sample ratios (N = 67) of overall length to aper- ture length were found to be normally distrib- uted at the 0.05 confidence level; x^ = 7.65, d.f. = 7 (Table 4). The denticulation on the rachiglossate radula varied greatly but bore no correlation to the size of the individual. There was also no observed correspondence between an increased number of denticles on the rachidian and lateral teeth. The numbers observed for rachidian denticles were: 20 individuals with four denticles, 27 with five, 13 with six, three with seven and one with eight denticles. The denticulation on the lateral teeth varied less; there were four individuals with four, 46 with five, and 14 with six. Some of the radulas are illustrated in Figures 3 to 8. The variations observed in knobbiness, aperture col- Tumidity Knobs Forward Recurved Both Totals Present Absent Totals 7( 8.57) 12(10.49) 19 16 (15.22) 18 (18.78) 34 7 ( 6.27) 7 ( 7.73) 14 30 37 67 oration, and number of denticles in teeth corresponds to those found by TABLE 4. Chi-square "goodnes of fit" test for continuous data, using the Null Hypothesis th the model Y-N (1.21005, 0.000962681. x- = 7.65 the radular Magalhaes Normality on at the data fits , d.f = 7. 0.05 TABLE 2. Contingency Table using the Chi-square "good- test for the Null Hypothesis that the variables, f Knobbation and Aperture Coloration, are inde- each other. Expected freq-uencies are in paren- to the observed frequencies, x- = 7.66. d.f = 6, nee level. confidence level. riess of fit" Direction q pendent of thesis yiext 0.05 confidi Class 1 2 3 4 Class Interval 0.00- 1.13 1.13- 1.15 1.15- 1.17 1.17- 1.19 Observed 1 0 2 12 Expected 0.27 1.31 4.55 10.27 Knobs Coloration Forward Recurved Both Totals 5 6 1.19- 1.21 1.21 - 1.23 19 16 15.75 16.23 Red Orange Yellow Pale Yellow Totals 1 (0.85) 1 ( 1.52) 1 (0.63) 3 4 (5.96) 13 (10.66) 4 (4.39) 21 4(6.52) 13(11.67) 6(4.81) 23 10(5.67) 7(10.15) 3(4.18) 20 19 34 14 67 7 8 9 10 Totals 1.23- 1.25 1.25 - 1.27 1.27- 1.29 1.29 ■< 11 3 2 1 67 11.28 5.27 1.65 0.40 66.97 148 THE NAUTILUS July 10, 1981 Vol. 95(3) FIGS. 3 to 8. Examples of obsemed variation in radular of Busycon. Rachidian tooth (a) and lateral (b) teeth: in- dividuals J,2(Z), 53(4), 5.4(5), 52(6), UC!) and j,9(6). (1948). Variation in the ratio of overall length to aperture length compared to the variation Ma- galhaes (1948) measured in spire height (Fig. 2). Although the zymograms produced clearly discernible banding patterns, all of the six en- zymes analyzed (N = 67) were monomorphic. In- traspecific monomorphism in electrophoretic banding patterns seems to be typical throughout the Busycon genus, based on preliminary data (Jerry Harasewyzh, personal communication). DISCUSSION The purpose of this study was to determine which genetic and morphological differences within the local Busycon could be identified and to relate such variation to the taxonomy of the genus. The sample exhibited interpopulation normality while displaying characteristics at- tributed to two different taxa, Busycon carica and B. eliceans. These findings led to questions involving the validity of these taxa. Hollister (1958) separated B. carica from a dextral sympatric species, B. eliceans, in the adult form by the presence of a tumid ridge that runs across the back of the siphonal canal and a more rugged and knobbed shell in the latter. More recently, Abbott (1974) has reassigned B. eliceans as a subspecies under B. canca using tumidity, knobbiness and aperture coloration for distinction. He has listed B. carica as having no tumidity, low knobs and yellow-orange to red aperture coloration; while the subspecies eli- ceans has a tumidity, rugged knobbed shoulders and a white aperture with yellow and brown suf- fusions (this coloration corresponds to our pale yellow color designation). In the sample studied, no correlation between the presence of a tumid ridge and the direction of knobbiness was observed, and the colorations corresponding to the presence of a tumidity were not those listed in the literature. Of the 44.75% of the popula- tion that possessed tumidities, 50% had yellow apertures, 33.3% had orange apertures, 10.0% had pale yellow apertures and 6.7% had red apertures. We detected no polymorphism in the enzymes that we studied; however, it is important to remember that electrophoretic measurements give minimum estimates of variation (Selander, 1976). So, although no evidence of polymorph- ism was found, it is not possible to draw final conclusions about the inherent genetic variabil- ity of the population from this data. However, since the same techniques have been used to ex- amine electrophoretic variation in other marine invertebrates, conclusions can be drawn by com- paring our data with the results of previous work. Monomorphism such as we detected is ex- tremely unusual, particularly in marine inverte- brates which are among the most variable groups studied, exhibiting 5% to 50% poly- morphic loci and 5% to 15% heterozygosity (Selander, 1976). Specific studies on five marine gastropod species showed a 17.5% polymorphic loci and 8.3% heterozygosity in 17 studied loci (Selander, 1976). Therefore our results are a radical departure from previous work on similar groups and are consistent with the hypothesis that we observed a population of a single species, particularly since intraspecific mono- morphism of electrophoretic banding patterns seems to be typical of Busycon (Jerry Harasewych, personal communication). A subspecies as defined by Mayr (1963) is "an Vol. 95(3) July 10, 1981 THE NAUTILUS 149 aggregate of local populations of a species in- habiting a geographic subdivision of the range of the species and differing taxonomically from other populations of the species" (p. 672). It has been suggested that species be divided into taxo- nomic subspecies if more than 75% of the indi- viduals can be recognized as belonging to one or the other taxa (Mayr, 1969). In this study the percentage of specimens that could be recogniz- ed as being of one or the other defined sub- species (Abbott, 1974) was only 34.3%, not suffi- cient to support a subspecies division. We are left to conclude that the observed specimens in this particular area represent a population of a single species. Reasons for the observed variation within this species may be related to environmental adapta- tion. Vermeij (1978) identifies factors that con- tribute to the production of morphological varia- tion in gastropods. Calcification efficiencies, predation pressures, and lack of certain sub- strate constraints may induce greater morpho- logical diversity toward the southern end of the species range, accounting for increased thick- ness and knobbiness of southern shells (Vermeij, 1978). Clinal variation, often used to classify populations within a species (Mayr, 1970), could also explain the morphological variation observ- ed in B. carica; however, the word cline refers to a specific character (such as knobbiness), and a species may contain many clines. So although useful as a component of species structure, the character of the word makes it undesirable as a taxonomic divider. The description of a species should be exten- sive enough to include the variations in the dif- ferent parts of its range (Pulley, 1959). In the population we observed there were no indica- tions that its variation necessitates the separa- tion of individuals into either two separate species or subspecies. Therefore we conclude that the population in Wassaw Sound, while in- :luding individuals whose characteristics might classify them as either B. carica orB. eliceans, is 1 single population and that the subspecies aame eliceans is unnecessary in the taxonomy of :he Busycon from this locale. ACKNOWLEDGMENTS We are indebted to the following persons: Dr. John Avise, Dr. David Gillespie, Bretton Kent, Dr. James Porter and Dr. Grace Thomas for critical examination of the manuscript; Charles Aquadro and Dr. John Avise for assistance and use facilities; Randy Walker for assistance with field work; and the University of Georgia Ma- rine Extension Service where the major part of this work was carried out. This work was par- tially funded by Georgia Sea Grant #NA 79- AA-D-00123. The U.S. Government is authorized to produce and distribute reprints for governmental pur- poses not withstanding any copyright notation that may appear hereon. LITERATURE CITED Abbott, R. T. 1974. American Seaskells. 2nd Edition, Van Nostrand Reinhold Co., New York. 663 p. Ayala, F. J. and J. W. Valentine. 1977. Genetic Variation and Resource Stability in Marine Invertebrates. In Marine Organisms, Genetics. Ecology and Evolution. Ed., Bruno Battaglia and James Beardmore. Plenum Press, New Yorli. 23-51. Avise, J. Personal Communication. University of Georgia, Genetics Department, Athens, Georgia 30602. Bhattacharyya, G. K. and R. A. Johnson. 1977. Statistical Concepts and Methods. John Wiley and Son, New York. 639 p. Brewer, G. J. 1970. Introduction to Isoenzyme Techniques. Academic Press, New York. 186 p. Chambers, Steven M. 1978. An electrophoretically detected sibling species of "Goniobasis floridensis" (Mesogastro- poda: Pleuroceridae). Malacologia 17(1):157-162. Dobzhansky, T.. F. J. Ayala, G. L. Stebbins and J. W. Valen- tine. 1977. Evolution. W. H. Freeman and Co. 572 p. Harasewych, J. Personal Communication. University of Del- aware, College of Marine Studies, Newark, Delaware 19711. Hollister, S. C. 1958. A review of the genus Busycon and its allies. Palentog. Amer. 4:49-126. Levins, R. 1968. Evolution in Changing Environments. Princeton University. Press. Princeton, N.J. 120 p. Levinton, J. 1973. Genetic variation in a gradient of environ- mental variability: Marine bivalvia (Mollusca). Science 180:75-76. Lewontin. R. C. 1958. The adaptations of populations to varying environments. In Cold Spring Harbor Symposia on Quantitative Biology 22:395-408. Magalhaes, Hulda 1948. An ecological study of snails of the genus Busycon. at Beaufort, N.C. Ecological Monographs 18:377-409. Mayr, E. 1963. Animal, Species and Evolution. Belknap Press of Harvard Univ. Press. Cambridge, Mass. 797 p. 150 THE NAUTILUS July 10, 1981 Vol. 95(3) 1969. Principles of Systematic Zoology. Mc- Graw-Hill, New York. 428 p. 1970. Populations, Species and Evolution. Belknap Press of Harvard Univ. Press. Cambridge, Mass. 453 p. Mendenhall, W. 1968. The Design and Analysis of Experi- ments. Duxbury Press. Belmont, Calif. 465 p. Poulik, M. D. 1957. Starch gel electrophoresis in a dis- continuous system of buffer. Nature 180:1477-1479. Pulley, T. E. 1959. Busycon perversum (Linne) and some related species. Rice Institute Pamphlet 46:70-89. Schall, B. A. and W. W. Anderson. 1974. An outline of tech- niques of starch gel electrophoresis of enzymes from the American oyster, Crassostrea virginica Gmelin. Georgia Marine Science Center, Technical Report Series. Unpub- lished manuscript. Selander, R. K. 1976. Genetic variation in natural popula- tions. From: F. S. Ayala (Ed.), Molecular Evolution. Sinauer Assoc. Inc. Sunderland Mass. 21-45. Stanley, S. M. 1979. Macroevolution: Patterns and Process. Freeman and Co., San Francisco. 332 p. Skibinski, D. 0. F., J. A. Beardmore and M. Ahmad. 1977. Genetic aids to the study of closely related taxa of the genus Mytilus. In Marine Organisms, Genetics, Ecology and Evolution. Ed., Bruno Batteglia and James Beard- more, Plenum Press, New York. 469-486. Valentine, J. W. 1976. Genetic strategies of adaptation. From: F. S. Ayala (ed.). Molecular Evolution. Sinauer Assoc. Inc. Sunderland, Mass. 78-94. Vermeij, G. J. 1978. Biogeograpky and Adaptation; Pat- terns of Marine Life. Harrard Press, London. 331 p. Vernberg, W. B. and F. J. Vernberg. 1972. Environmental Physiology of Marine Animals. Springer-Verlag, New York. 346 p." Walker, R. L. Intertida! populations of whelks (Busycon spp.) in Wassaw Sound, Georgia. In preparation. Walker, R. L., M. A. Fleetwood and K. R. Tenore. 1980. The distribution of the hard clam, Mercenaria mercenaria (Linne) and clam predators in Wassaw Sound, Georgia. Georgia Marine Science Center Technical Report 80- 859 pp. THE GASTROPODS, CALLIOSTOMA ORION DALL, 1889 (TROCHIDAE) AND HELIACUS (GYRISCUS) WORSFOLDI N. SP. (ARCHITECTONICIDAE), FROM THE BAHAMA ISLANDS James F. Quinn, Jr. Florida Department of Natural Resources Marine Research Laboratory 100 Eighth Ave., S. E. St. Petersburg, PL 33701 ABSTRACT Heliacus (Gyriscus) worsfoldi n. sp., is described from the northwestern Bahamas. Calliostoma orion Dall, 1889. is redescribed and the radula and jaws are illiistrated by SEM micrographs. Calliostoma orion lives in and. feeds upon the tube sponge. Spinosella vaginalis. Heliacus worsfoldi, the first record of the subgenus Gyriscus in the western Atlantic, is associated with a species of Zoan- thus or Parazoanthus. The use of SCUBA equipment by shell collec- tors has opened an immense area of heretofore inaccessible ocean bottom for examination. This is especially true of the deep fore-reef zone of coral reef tracts such as occur in the Bahama Islands. Numerous specimens of gastropods col- lected near Freeport, (Jrand Bahama Island, were loaned to me for identification by Mr. Jack Worsfold. Among these specimens are some representing two species with unusual biological associations. Type-specimens are deposited in the collec- tions of the U. S. National Museum of Natural History, Washington, D.C., the Academy of Natural Sciences, Philadelphia, Pennsylvania, and the Florida Department of Natural Re- Vol. 95(3) July 10, 1981 THE NAUTILUS 151 sources, Marine Research Laboratory, St. Petersburg, Florida, abbreviated USNM, ANSP, and FSBC I respectively. Additional specimens are in the personal collections of Messrs. Jack Worsfold and Bob Quigley, Free- port, Grand Bahama Island. Family Trochidae Rafinesque, 1815 Genus Calliostoma Swainson, 1840 Calliostoma orion Dall, 1889 Figures 1-13 Calliostoma orion Dall, 1889a: 367, pi. 28, fig. 2; 1889b: 162.-Pilsbrj', 1889; 383, pi. 48. fig. 18.-Johnson, 1934: 70. -Clench and Turner, 1960: 54, pi. 35, figs. 1, 2. Description -SheW medium in size, height to about 16 mm, turbinate, imperforate, delicately sculptured by numerous spiral rows of small beads, teleoconch whorls 8-8 V2; color straw or bone white, often with nebulous areas of light- brown, always with fine, spiral brown lines. Pro- toconch small, white, IV2 whorls. Early teleo- conch whorls flat-sided, last 3 distinctly convex. Spiral sculpture of 20-26 fine cords ornamented by small, sharp, spirally elongate tubercles; cords generally alternate in size. Base almost flat, sculptured by 28-40 smooth spiral cords, generally every fourth larger and colored brown; cords made somewhat undulate by ir- regular growth lines. Aperture subquadrate; outer lip thin, simple; columella short, thick, straight, white. Operculum thin, multispiral, light amber in color. Radula typically calliostomatine (Figures 3, 4). FIGS. 1 and 2. Calliostoma orion Dall. 1889. 1, Apertural view, USNM 784595, U.8 mm high. 2, Basal view of same specimen. Rachidian slender, base pyriform, with long, slender, finely denticulate cusp. Laterals 5; bases pyriform, becoming rhombic on distal 2 (Figure 5); cusps long, slender, becoming very slender on outer laterals, finely denticulate on both sides. Marginals numerous, about 25-30 per half-row; inner marginal large, massive, usually with 6-8 large, strong teeth on proximal margin of tip, finely denticulate on distal mar- gin, with prominent buttress opposite toothed margin (Figure 6); succeeding inner marginals of similar, although less massive, structure without buttress (Figures 4, 6, 7); outer margin- als very slender, whisker-like, with fine teeth along both sides of tip, occasionally smooth. Jaws chitinous, subrectangular, rounded an- teriorly and posteriorly, fringed anteriorly (Figures 10, 11). Two major plates joined dor- sally by pair of smaller, elongate, corrugated plates (Figures 9, 10). Outer surface of jaws comprised of small, elongate, hexagonal or diamond-shaped scales (Figure 12); inner sur- face vaguely reflecting outer texture (Figure 13). Holotype-VSNU 214272. Height 4.5 mm; maximum diameter 4.2 mm. Type-locality -BhAKE station, off Havana, Cuba, 146 m. Material examined -BLAKE station, off Havana, Cuba, 146 m; 1 spec, USNM 214272 (Holotype).-Off Tamarind, Lucaya, Grand Bahama Island, Bahamas, on sponge, 15-43 m, J. Worsfold collector; 1 spec, USNM 784595; 1 spec, USNM 784597; 2 spec, ANSP 353315; 1 spec, FSBC I 22163; 1 spec, FSBC I 23777.- Little San Salvador, Bahamas, on sponge, 34 m, J. Tyler collector; 1 spec, USNM 706809.- Providencia Island, Colombia, N. A. Roberts, leg.; 1 spec, ANSP 316567. Distribution -Known from the eastern and northwestern Bahamas, northern Cuba, and the western Caribbean off Nicaragua, at depths of 15-43 m and 146 m. Remarks -Until now Calliostoma orion has been known from only two shells: the holotype, a juvenile, collected from 146 m off Havana; and a second specimen found at Arenas de la Chor- rera in sand dredged from 5-27 m off Sante Fe, Cuba (Clench and Turner, 1960). Both speci- 152 THE NAUTILUS July 10, 1981 Vol. 95(3) FIGS. 3-7. SEM micrographs of radida o/Calliostoma orionDaH, 1S89 (FSBC 1 22163). 3, Composite micrograph ofradula; 75 x. 4, Segment showing laterals and marginals; note deritieulatwn of prox- imal and distal edges of marginals: SOOx. 5, Detail of outer two laterals; apparent fusion of several teeth is an artifact of mounting; J,12 x . 6, Detail of tip of first inner marginal showing heavy buttress; 638 x. 7, Marginal f rem, middle of marginal half-row; 600 x. mens are bone white in color with the character- istic spiral brown lines very faint. The speci- mens from Providencia and Little San Salvador Island are also albinistic. However, all specimens examined from Grand Bahama Island are rather richly colored, with brown clouds Vol. 95(3) July 10, 1981 THE NAUTILUS 153 E /■/ « , f "'T'"^''"' * "■' '""■" '-'.'■ Calliostoma orion Dall. 1889 (FSBC 1 22163). 8, Anterior )rnge oj left lateral plate; S75x. 9, Surface detaU of dorsal conr^cting plates; S75>.. 10, Left latZal pla e and u,o dorsal plates, external surface; 60.. 11, Right lateral pMe, ^nt^nalsurfaJ;6oTl2 Lateral plate external surjace microsculpture of elongate hexagonal and tetragonal scales; 150 x' 13 Lateral plate internal surface microsculpture: 150 X. . • lo. superimposed on a straw-colored background, and numerous, distinct brown spiral lines. In outline, Calliostoma orion is extremely similar to C. marionae Dall, 1906. The upper whorls are flat-sided, forming an evenly conical spire, but the last 2 or 3 whorls are convex, with the base remaining almost flat throughout. The whorl periphery becomes less angular as growth 154 THE NAUTILUS July 10, 1981 Vol. 95(3) progresses. Calliostoma orion also differs from C. maricmae in having beaded sculpture and no umbilicus, as well as being considerably smaller. The very small, sharply-pointed beads on the up- per part of the whorls and the shape of the shell immediately separate C. orion from other im- perforate species, such as C. euglyptum (A. Adams, 1854) and C. sarcodum Dall, 1927, with which it may be confused. The radula and jaws are very similar to those described and illustrated for the subgenus Cal- liostoma as restricted by Clench and Turner (1960). In this subgenus there are five marginals with long, slender cusps, a massive inner margi- nal followed by a number of teeth of less massive but similar structure, and an outer series of very slender marginals. The radula of C. orion differs primarily in the shape of the first marginal tooth, especially the buttressed tip and slender rhachis which are more similar to those in the subgenera Kombologion Clench and Turner, 1960, and Elmerlinia Clench and Turner, 1960. Until radulae of more species of Calliostoma are examined using SEM, I refrain from assigning C. orion to a subgenus. This species, as far as is known, occurs only on deep reefs of the northern and western Carib- bean islands. It is not uncommon in depths from 15 to 43 m (50-140 ft) and is always found in the tube sponge, Spinosella vaginalis (Lamarck, 1814), in the Bahamas (J. Worsfold, personal communication). A number of recent papers have documented the feeding of Calliostoma species on coelenterates (Lang, 1970; Salvini- Plawen, 1972; Francis, 1973; Miller, 1973; Per- ron, 1975; Perron and Turner, 1978), bryozoans (Perron, 1975), and dead animal flesh (Keen, 1975; Perron, 1975), in addition to the herbi- vorous or detrital diets previously thought characteristic of all trochids. An examination of the contents of the intestine of a specimen of C. orion revealed numerous spicules of Spinosella vaginalis (straight oxeas), cellular material of indeterminate origin, and small calcareous frag- ments. In view of the previous observations of oppc feeding of Calliostoma spp. and the f.. "< sponge spicules in the fecal material don, it is probable that this species does in fact feed on Spinosella, the first such observation for Calliostoma. Family Architectonicidae Gray, 1850 Genus Heliacus Orbigny, 1842 Subgenus Gyriscus Tiberi, 1867 Heliacus (Gyriscus) worsfoldi n. sp. Figures 14, 15 Description- Shell small, height to 7.3 mm, solid, turbinate, umbilicate, with high spire; whorls rounded, sculptured by spiral rows of beads; color of shell whitish to light mauve, with 8-10 axially elongate blotches of light-brown around periphery; umbilicus purplish brown within, columella stained with purplish brown. Protoconch anastrophic, prominent, glassy, brown, 0.84 mm in greatest diameter. Teleo- conch whorls 4, subtubular, with 5 or 6 beaded, spiral cords above periphery and 8 or 9 (rarely 7 or 10) on base; axial sculpture of low, rounded, flexuous threads. Umbilicus narrow, about 15% of greatest shell diameter, lightly wrinkled by growth lines. Aperture circular; outer lip thin, crenulated by external sculpture; columella con- cave, lip slightly reflected, smooth. Operculum thin, circular, multispiral, light-brown in color; external surface concave, with concentric over- lapping foliations; nucleus central; inner side with prominent, clockwise-spiraled central plug. A color slide (ex J. Worsfold) of the ventral view of a specimen with animal expanded shows the foot deeply bifid anteriorly and broadly FIGS. 14 and 15. Heliacus (Gyriscus) worsfoldi Quinn, n. sp. 14, Apertural view ofholo'type. USNM 78J,593. 7.S mm high. 15, Basal view of sarne specimen. Vol. 95(3) July 10, 1981 THE NAUTILUS 155 rounded posteriorly. Color of foot light mauve, with numerous spots of opaque white. Tentacles long, tapering gradually to rather bluntly round- ed tips; color Hght mauve, with zig-zag markings of darker purple. Radula not preserved. Holotype -USNM 784593. Height 7.3 mm; maximum diameter 6.2 mm. Type-locality -Off Settlement Point, Grand Bahama Island, 12.2 m, J. Worsfold and B. Quigley, collectors. Paratypes -USNM 784596, 2 spec; FSBC I 23778, 2 spec; ANSP 353241; 2 spec; J. Wors- fold and B. Quigley collections, 43 spec; all specimens with same data as holotype. Remarks -Heliacus worsfoldi is the third known species of the subgenus Gyriscus, which was established by Tiberi (1867) for Gyriscus jeffreysianus Tiberi, 1867, described from off Sardinia, Italy. One of the three syntypes of H. jeffreysianus is in the USNM and has been re- iescribed by Merrill (1970). Specimens of the new species are superficially very similar to those of H. jeffreysianus but are smaller, have a smaller protoconch [range 0.810-0.875 mm, x = D.84 mm for H. worsfoldi; 0.95 mm for H. jef 'reysianus (Merrill, 1970)], have fewer primary spiral cords (5 or 6, not 7), lack intercalarj' secondary spiral threads, have a proportionally larrower umbilicus (H. ivorsfoldi: 15% of maxi- Tium shell diameter; H. jeffreysianus: 20%), and ire a different color. Powell (1965) described lyriscus asteleformis from off the northern tip )f North Island, New Zealand, from a depth of )0 fathoms. Powell's species differs from H. riirsfoldi in being larger, proportionally iroader, uniformly buff-colored, in having more lumerous and more finely beaded spiral cords. md a larger umbilicus. All of the specimens of H. worsfoldi were col- ?cted together on a specimen of the antipath- rian, Cirripathes sp., which was largely en- insted by a species of Zoanthus or Parazoan- 'lus. Previously, architectonicids have been bserved in association with scleractinian corals ilobertson, Scheltema and Adams, 1970) and ne zoanthiniarians Zoanthus and Palythoa Robertson, 1967; Marche-Marchad. 1969), and owell (1965) reported Heliacus (Gyriscus) steleformis from the ca\ity of a sponge. Robertson (1981) has recently reviewed the gas- tropods symbiotic with zoanthiniarians, of which assemblage Heliacus was a major constituent. It is therefore probable that H. worsfoldi is also svTnbiotic with the zoanthid, although the possi- bility of an association with antipatharians can- not yet be dismissed. ACKNOWLEDGMENTS I am grateful to Mr. Jack Worsfold who brought the two species to my attention and who kindly donated the tj'pe material. Sally D. Kaicher made the excellent photographs, and W. G. Lyons and D. K. Camp reviewed the manuscript. Lana Tester provided SEM serv- ices. LITERATURE CITED Clench, W. J, and R. D. Turner. 1960. The genus Calliosto- ma in the western Atlantic. Johnsonia 4(40):l-80. Dall. W. H. 1889a. Reports on the Mollusca. Part II. Gastro- poda and Scaphopoda. Reports on the results of dredg- ing .. . in the Gulf of Mexico (1877-78) and the Caribbean Sea (1878-80), by the U. S. Coast Sur\-ey steamer "Blake" . . . Bull. Mils. Comp. ZooL, Han: 18:1-492. 1889b. A preliminary' catalogue of the shell- bearing marine mollusks and brachiopods of the south- eastern coast of the United States. Bull. U. S. Natl. Mus. 37:1-221. Francis, L. 1973. Intraspecific aggression and its effect on the distribution of Anthopleura elegantissima and some related sea anemones. Biol. Bull. 144:73-92. Johnson, C. W. 1934. List of marine Mollusca of the Atlan- tic coast from Labrador to Texas. Proc. Bost. Soc. Nat. Hist. 40:1-204. Keen, A. M. 1975. On some western American species of Calliostoma. The Veliger 17:413-414. Lang, J. C. 1970. Inter-specific aggression within the scler- actinian reef corals. Unpubl. Ph.D. Dissertation, Yale University. 80 pp. Marche-Marchad, I. 1969. Les Architectonicidae (Gastro- podes prosobranches) de la cote occidental d'Afrique. Bidl. Inst. Found. Afr. Noire, Serie A. 31:461-486. Merrill, A. S. 1970. The family Architectonicidae (Gastro- poda: Mollusca) in the western and eastern Atlantic. Un- publ. Ph.D. Dissertation, Uni\'ersity of Delaware, 338 pp. Miller, A. C. 1973. Obser\'ations on the associations and feeding of six species of prosobranch gastropods on antho- zoans in Discovery Bay. Jamaica. Echo 5:35-36. Perron. F. E. 1975. Carnivorous Calliostoma (Prosobran- chia: Trochidae) from the northeastern Pacific. The Veli- ger 18:52-54. Perron, F. E. and R. D. Turner. 1978. The feeding behavior and diet of Calliostoma occidentale, a coelenterate-associ- I 156 THE NAUTILUS July 10, 1981 Moll. Stud. 44: ated prosobranch gastropod. Joum. 100-103. Pilsbry H A 1889. Trochidae, Stomatiidae, Pleurotoman- idae.'Haliotidae. In: G. W. Tryon, 1879-1913, Manual ofConchology, Series 1, vol. 11. Philadelphia, 519 pp. Powell A W. B. 1965. New Zealand molluscan systematics with 'descriptions of new species: Part 5. Rec. Auckl. Inst. Mus. 6(2):161-168. Robertson, R. 1967. Heliacus (Gastropoda: Architectonici- dae) symbiotic with Zoanthiniaria (Coelenterata). Science 156:246-248. Vol. 95(3) 1981. Gastropods symbiotic with zoanthid sea anemones. Bull. Amer. Malacol. Union for 1980: 69 (ab- stract). Robertson, R., R. S. Scheltema and F. W. Adams. 1970. The feeding, larval dispersal, and metamorphosis of Philippta (Gastropoda: Architectonicidae). Pacific Science 24:55-65. Salvini-Plawen, L. v. 1972. Cnidaria as food sources for marine invertebrates. Cahiers Biol. Mar. 13:385-400. Tiberi, N. 1867. Diagnose du nouveau genre mediterraneen Gyriscus. Joum. de Conchyl. 15:303. SECOND, REVISED AND IMPROVED PRINTING - July 15, 1981 GUIDE TO THE NUDIBRANCHS OF CALIFORNIA INCLUDING MOST SPECIES FOUND FROM ALASKA TO OREGON By Gary R. McDonald and (Edited By R. Tucker James W. Nybakken Abbott) Destined to be the "bible" tor tidepool and stuba biologists, the Guide to the Nudihranchs of Catiiornia will equally serve those researchers from Alaska and Pacific Canada to Oregon. The extensive information on the specialized foods and habitats of each species will aid not only in identification but also in ecological analyses. Unique among similar guides, this book has the advantage of ex- tensive keys, authoritative information and convenient phylogenetic organization. This Iwok will be welcomed by marine biologists, amateur naturalists, marine aquarium enthusiasts, and students of oceanography. Years in the making, this compact account gives the scientific essentials to all the known nudihranchs snails of California, including the higher classification and descriptions oi each genus with their type-species. 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Part 1: The Genera A^as- uria, Trajana and Neoteron. 50 pp. By Walter 0. Cernohorsky. $7.50. Postage free if order is ac- ompanied by payment. Foreign subscribers please add $1.00 for postage. American Malacologists, nc. P.O. Box 2255, Melbourne, FL. 32901. U.S.A. 158 THE NAUTILUS July 10, 1981 Vol. 95(3) Freshwater Snails of Africa and their Medical Importance by David S. Brown For the first time: A comprehensive account of freshwater snails in Africa and neighbouring islands. An exhaustive guide to species of medical and veterinary importance. An invaluable reference work for malacologists, epidemiologists, parasitologists, freshwater biologists and biogeographers. Published by TAYLOR & FRANCIS LTD, LONDON. Distributed in the Americas by AMERICAN MALACOLOGISTS, INC. FLORIDA. The knowledge resulting from intensive study in recent years is brought together for the first time in this book. 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THE BEST OF THE NAUTILUS. 1976. 288 pp.An exciting and nostalgic anthology of shell collecting In the Nineteenth Century ISBN 0-915726-02X Cloth $13.95 Arakawa. K, Y SHELLS ON STAMPS OF THE WORLD. 1979. 234 pp., 16 color pl3.; text llgs. Illus. Catalog and classifications. ISBN 0-915826-07-0 Cloth $15.95 Bouchel, P. SEASHELLS OF WESTERN EUROPE. 1980 (Jan.). 144 pp, all color, living animals, habitats. ISSN 0-915826-05-4 Paperback $ 8.95 HoubrIck, Richard S. THE FAMILY CERITHIDAE IN THE INDO-PACIFIC. 1979. 130 pp., 98 pis , 3 In color. Monographs of Marine Mollusca no 1, with buchram looseleaf binder. ISSN 0162-8321 $26.00 Wagner, R. J. L. • Abbott, R. Tucker. STANDARD CATALOG OF SHELLS. 1978, with supplement no. 1 (1978). 460 pp. Values, world size records, lists, maps, hundreds of figs., some In color 15,000 entries ISBN O-91582603-8 Buchram postblnder $40.00 McDonald and Nybbaken, 1980. 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PUBLISHERS OF DISTINCTIVE BOOKS ON MOLLUSKS THE NAUTILUS (QuaHerly) MONOGRAPHS OF MARINE MOLLUSCA STANDARD CATALOG OF SHELLS INDEXES TO THE NAUTILUS (Geographical, vols 1-90; Scientific Names, vols 61-90) REGISTER OF AMERICAN MALACOLOGISTS OCTOBER 29, 1981 THE NAUTILUS ISSN 0028-1344 Vol. 95 No. 4 r Marff>i> Sf^c^;^?Uj?^Of£tafY ■m^ i^^: " '' ^' ■Ko':'^ A quarterly devoted to malacology and ,./^ the interests of '^"' conchologists Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker. Editor-in-Chief: R. Tucker Abbott EDITORIAL COMMITTEE CONSULTING EDITORS Dr. William J. Clench Curator Emeritus Museum of Comparative Zoology Cambridge, Mass. 02138 Dr. William K. Emerson Department of Living Invertebrates The American Museum of Natural History New York, New York 10024 Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, Ohio 43210 Dr. James H. 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Box 2^55, Melbourne, Florida 32901 Mrs. Cecelia W. Abbott Business and Subscription Manager P.O. Box 2255 Melbourne, Florida 32901 Tlie Nautilus (USPS 374-980) ISSN 0028-1344 OFFICE OF PUBLICATION American Malacologists, Inc. (United Parcel Address: 2208 South Colonial Drive, Melbourne, FL 32901) Mail: Box 22.55, Melbourne. FL 32901 Seamd Qass Postage paid at Melbourne, Florida and other post offices Subscription Price: $12.00 (see inside back cover) $14.00 (foreign); institutions $18.00 THE NAUTILUS Volume 95, number 4 - October 29, 1981 ISSN 0028-1344 CONTENTS Joseph Rosewater Malacological Journey into Cuba, 1980 159 Paul M. Tuskes Population Structure and Biology oi Liguus Tree Snails on Lignumvitae Key, Florida 162 Harald A. Rehder A New Species of Volutocorbis (Volutidae), from Somalia 169 G. 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THE NAUTILUS October 29, 1981 Vol. 95(4) The first ntnckulogiral work hy an Aint-rtrnn published in America, Thomas Say's CONCHOLOGY 1819 A beautiful f(wMmile copy of the third edition of Say's fundemerifal work from Nicholson's British Encyclopedia Philadelphia 1819 Tliis rare work, never before reproduced in full, con- tains 2(1 pages and four lithograph plates of Say's new land and freshwater species of mollusks. This is the expanded version of the first (1816) and second (18 IS) edition. 32 pages, paperbound. The preface, by R. Tucker Abbott, tells the history of this article and gives brief biographies of the author, the editor, the publisher and the printer. Limited edi- tion. S.S.OO, including postage. Foreign postage, please add .$1.00. Amkkican Malac(ilik;ists. Inc. P ( ), Bdx 22:,:, Melh.iuriie. FL :iaKll-(i:!28 american malacologists (305) 725-2260 P O BOX 2255 MELBOURNE, FLORIDA 32901 USA PfllLISHEHS (IF IiISTI.\(TIVF: lidOhS ti\ .MOI.IJSKS Abbott, R Tucker, editor. 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INC. y P O Box 2255, Melbourne, FL 32901 USA > Vol. 95(4) October 29, 1981 THE NAUTILUS 159 MALACOLOGICAL JOURNEY INTO CUBA, 1980 Joseph Rosewater Division of Mollusks National Museum of Natural History Smithsonian Institution, Washington, D.C. 20560 The Smithsonian and the Academia de Cien- cias de Cuba have joined in an exchange pro- gram whereby scientists of both institutions may visit the other and conduct research of mutual interest. Several Smithsonian scientists have done this: Raymond Manning and Mere- dith Jones (Crustacea and Worms), were early participants (1978). Storrs Olson (Birds) trav- eled to Oriente Province in October 1980 for a joint ornithological expedition; Porter Kier (Fossil Echinoids) visited during late October 1980 and worked in the Geological Institute col- lections. Early in 1980 I indicated an interest in participating in the exchange program. It was my feeling that a Smithsonian malacologist should visit Cuba, renew acquaintances with old colleagues, meet new ones, and begin to re- establish what was a very active program of cooperative research.' Another very important reason for wanting to visit Cuba was the hope of examining old and new collections of research interest and to carry out field work. As it turned out I accomplished all but some hoped-for field work in Pinar del Rio, that mecca for Cuban land Mollusca. I boarded the plane at National Airport, left Washington at 7:30 a.m. on November 10, 1980, and arrived in Toronto, Canada, my Cuban disembarkation point, at 10:30 a.m. The Havana bound A ir Canada flight left Toronto at noon and arrived at 3:30 p.m. Upon arrival in Havana the passengers from the Air Canada DC-8 were gathered into the terminal to await passport examination, a pro- cess which occupied at least an hour. My wel- 'For early accounts of Cuban visits see The Nautilus, vols. 25:3 (Webb, 1911); 26:2 (Henderson, 1912); 26:99, 111 (Wheeler, 1913); 27:136 (Henderson, 1914); 28:4, 49, 133 (Ramsden, 1914, 191.5); 31:41 (Henderson, 1917); 35:118 (Remington, 1922); 38:.56 (Emery, 1924); 40:37, 88 (Hand, 1926, 1927), and 62:78 and 7o!l (.Jao.bson, 1949, 1956) [editor]. coming party patiently waiting outside the cus- toms shed consisted of Dr. Fernando Gonzalez Bermudez, director of the Instituto De Zoologia, Academia De Ciencias De Cuba, Jose Fernandez Milera, Curator of Mollusks, and others. After warm greetings, and since it was then nearing 5:00 p.m., I was driven into the city to the residence for visiting scientists at no. 212 Prado (now Paseo San Marti) where I was to be housed and fed during my stay. The residence, once the house of an important official, is beautifully furnished in Spanish motif, replete with marble floors, stairways and statues. Rooms are large, well-furnished and air-conditioned. Three meals a day are served in the large well-attended dining room. While there I met scientists from France, Germany and other Latin American countries, for Cuba has cooperative research agreements with many countries. On the following morning I was picked up at 9:00 a.m. and driven to the Zoological Institute on the west side of Havana. The road traversed the Malecon, the famous Havana waterfront road that runs from the harbor entrance (Morro Castle) past the entire city proper. As those who have visited Havana already know, the down- town area boasts many large tourist hotels, one of the most prominent being "The Rivera". Upon arriving at the Zoological Institute a meeting was held during which I was introduced to staff concentrating on various malacological prob- lems: Jose Milera, who as I mentioned, is in charge of the Institute's mollusk collections; Jose Espinosa, who is collaborating with Hortensia Sarasua on systematic revisions of Cuban prosobranchs; Isabela Cortes Vico, of the Institute's Department of Terrestrial Ecology, who is working on problems concerning the es- tablishment of an escargot resource utilizing the large land snail, Zachrysia guanensis castanea; 160 THE NAUTILUS October 29, 1981 Vol. 95(4) and Renzo Rodriguez of the same department, who is working on cuituring Polymita to ensure its preservation in the face of destruction of the habitat and heavy collection pressure. Both of the latter workers are very anxious to contact U.S. scientists who can counsel them or provide references which would help with an under- standing of the ecology, dynamics of reproduc- tion, and trophic niches of Zachrysia and Polymita.^ At present both are being cultured in the laboratory and have passed through several generations. Various types of commercial food have been accepted by the snails, the most satisfactory results so far having been with Zachrysia feeding. The Polymita seem to offer more of a problem and Rodriguez is presently performing dissections on the digestive system to determine just what the animals are eating. He certainly would welcome suggestions or ref- erences on Polymita digestive system anatomy. The address at which they can be reached is: Departamento de Ecologia Terrestre, Institute de Zoologia, Academia de Ciencias de Cuba, Calle 212 #17A09, esq. 19, Atabey, Municipio Playa, Ciudad Habana, Cuba. Other malacological research currently being done in Cuba, so far as I could learn, is concern- ed with matters of public health and disease vec- tors. I made inquiries about fisheries research, but learned nothing and suggest that informa- tion may be obtained by contacting the fisheries directly. I am quite certain that mollusks are be- ing studied by other Cuban governmental in- stitutes such as Oceanology in connection with their research, but learned nothing definite. After discussing the above, the program was reviewed for the balance of my visit, consisting of laboratory and field studies on Cuban Littor- inidae. Also detailed were several extracurricu- lar activities, such as an evening tour of old Havana; an evening at the International Ballet which was then having its season in Havana; dinner at a roof-top restaurant downtown; and a much anticipated visit to the Museo Felipe Poey (which did not take place because the latter was ^Sec Thi Xinililiix. '■Sonif Habits ot" A Culian Snail Pdhpniln pirln Born" liv A. Iv Andrews. VXVZ. vol. 4(1. pp. 22-27 le.iiu.r!. being renovated). My approval of the proposed program was solicited and since the work por- tion, at least, was what I had hoped for - approv- al was freely given! There followed a toast (with Cuban banana brandy) to the success of the pro- gram. The afternoon was spent reviewing the work of the malacology section and in examin- ing collections. The next day, November 12, was spent at the malacology section with Milera examining, sort- ing and naming Cuban Littorinidae. Due to a number of nomenclatorial, distributional and ecological problems, it was agreed that we should co-author a study of that family in Cuba. As I was interested in tracking down as many of our colleagues as possible, I asked about Alfredo de la Torre, son of Carlos, and was told he works at the Institute de Geologia. Miguel Jaume, formerly Director of the Museo Felipe Poey, now retired, resides at Calle 42, #3307, Playa 13, Havana, Cuba. He visited me one day at the Institute, is a hearty 73, and was most in- terested in hearing about and being remem- bered to his colleagues in the U.S. I am sure he would welcome letters directed to the above ad- dress. He is busily engaged in a large biblio- graphic study on Cuban mollusks. Field work with Milera, Renzo and a driver, occupied four of the six full days I spent in Cuba. On Thursday, November 13, we traveled via Matanzas to Cardenas, about 150 km east of Havana. There we spent two days completing 15 stations around the Varadero peninsula. Milera, who is an excellent field man, took me to habitats where the maximum number of Lit- torina species would be found. Inclement weather and higher than normal tides seemed to have stimulated some of the Littorina to seek "higher ground", such as L. nebulosa, which we found to be clustered near the tops of pilings under estuarine conditions. On occasion there would be 100 or more on the top of a single pil- ing, more, claimed Milera, than he had ever noted previously! While near Varadero we col- lected on the shore near Xanadu, former du- Pont Estate, which has been maintained in lieautiful condition. The house is now a very elaborate restaurant. Vol. 95(4) October 29, 1981 THE NAUTILUS 161 Litforina ziczac. L. angusfior. L. lineolata, Tectarius muricatus. Nodilittorina tuberculata, and Echininus nodulosus all were collected on hard reef substrate, the latter three species often being found at highest shore levels. Lit- torina mespillum. the brown-spotted form, was found in rocky tide pools (a first for me). LH- torina meleagris was collected at lowest tide line, and L. angulifera was rare on mangrove and sea walls. In all, I collected 10 species of Lit- torinidae on the trip. Two more are known to live in Cuba, the possibly introduced Littorina flava. which lives only in the vicinity of Cien- fuegos, and Littorina te>isellata. also an inhabi- tant of the south coast. On Saturday, November 15, we traveled to the vicinity of Guira de Melena on the south coast of Cuba where we again collected Lit- torina nebulosa and Melampus cqffeus both of which were living in great profusion in man- grove and clustered on pilings at Playa Cajio. There were many Truncatella in the litter. At- tempts to collect at the port of Batabano were largely thwarted by high winds and rain. On Sunday, November 16, 1980, having evidenced interest in seeing Hemingway's home, I was taken there by Milera and party. The Hemingway estate is located in a suburb of Havana, in the town of San Francisco de Paula, overlooking the city. It is kept as a museum with ground, furniture and contents as they were when the author and his wife lived there. We collected some land snails on the grounds. From there we traveled to nearby Cojimar, a little fishing village that inspired Hemingway to write "The Old Man and the Sea". Collections were made there also (it was there that L. meleagris was found plentifully at low tide). The Cubans seem devoted to Hemingway, who made his home there for many years. While I may have had vague concerns about traveling to Cuba, by the time I had to leave, these had vanished. As those of you who have been there know, the country is a malacological paradise at least for marine and land mollusks. For those unfamiliar with Cuba, I recommend (to U.S. naturalists at least) they read Thomas Barbour's 1945 book, "A Naturalist in Cuba". It relates a great deal about the fauna and flora. and gives one a taste for the island. As a member of our malacological "fraternity" I felt I was genuinely accepted there, and left feeling that we have reestablished some of the old cooperative research interest with the Cubans, and that I accomplished much that I had hoped in going there. In many ways Cuba's contact with much of the rest of the malacological world -certainly ours -was largely severed 25 years ago. That means they have to catch up on much recent literature. For instance, Milera's laboratory lacks most of Johnsonia, Occasional Papers on Mollusks, The Nautilus. Malacologia, The Veliger. etc. They do not have Abbott's second edition of "American Seashells". I have obtained Abbott's book and have sent it to them and he has donated "American Malaeologists" and the Supplement. We are sending our reprints. Our International Exchange Service will supply quite a few volumes of the The Nautilus that re- main from a number Abbott gave the exchange two years ago. Cuban malaeologists wish to re- establish contact with their U.S. colleagues and to exchange literature with them. I know Jose Fernandez Milera and his colleagues would like to hear from other malaeologists. His address is: Departamento de Malacologia, Instituto de Zoologia, Academia de Ciencias de Cuba, Calle 212 #17A09, Esq. 19, Atabey, Municipio Playa, Ciudad Habana, Cuba. It is my understanding that mail, so directed, will now go through safe- ly, if not rapidly. Milera tells me he would be delighted to exchange specimens (prepared and/or preserved as you want them) for literature. It may be of interest to U.S. malaeologists that it is possible t\)r them to visit Cuba, and, in fact, I was encouraged to spread this good news to my colleagues. A Cuban Visa may now be legally obtained by U.S. citizens and travel is by way of Canada or Mexico via the airlines of those countries. Your travel agent should be able to provide the necessary information. Staff of the Instituto de Zoologia, and especially Milera, recommended your contacting them if you would like to have their guidance and helj.) in collecting and studying Cuban muliusks. 162 THE NAUTILUS October 29, 1981 Vol. 95(4) I departed Cuba on Air Canada at 5:00 p.m., Monday, November 17. It was 32° F and snow- ing when I arrived in Toronto and I was afraid the many living mollusks, for which I had an im- port license, would die of the cold shock. They survived, however, and following a night in Toronto I continued on to Washington the next day to conclude a fruitful and interesting trip. POPULATION STRUCTURE AND BIOLOGY OF LIGUUS TREE SNAILS ON LIGNUMVITAE KEY, FLORIDA. Paul M. Tuskes 1444 Henry Street Berkeley, California 94709 ABSTRACT Two named color forms o/Liguus fasciatus are native to Lignumvitae Key. The two color forms, simpsoni and lignumvitae constitute about 90% of the total population. The form simpsoni grows larger than lignumvitae in the dense ham- mock, but the opposite is true along the hammock edge. Individuals of both forms from the hammock edge, are significantly larger than individuals of the same form and age class from the central portion of the hammock. A population estimate suggests that there are about 28,500 snails on the Key in age classes 2 through 6 years. Three introduced forms of L. fasciatus; dryas, delicatus, and subcrenatus make up the remainder of the population. About 178 of the Key's 280 acres appears to be suitable Liguus habitat. Experiments examining the proba- bility of dispersal via rafting showed that Liguus died after short exposures to sea water. A great deal of work has been published re- garding the taxonomy of tropical tree snails in the genus Liguus. Much of the taxonomic work regarding Florida Liguus, done by Simpson, Clench, McGinty, and Pilsbry, was summarized by Pilsbry (1946) in his monograph on North American land molluscs. With the exception of a recent paper by Voss (1976), most articles re- garding Liguus biology have been popularized, presenting interesting but generalized informa- tion (Doe, 1937; Jones, 1954; Davidson, 1965). There is still a great deal to be learned regard- ing various aspects of their biology, but it has become increasingly difficult to find pristine col- onies of Liguus. Many colonies have been ad- versely influenced by human activity either through modification of the colonies' composi- tion (by the introduction and establishment of new forms), or the modification of the hammock habitat by lumbering or real estate develop- ment. The purpose of this study was to examine the population structure and evaluate the status of the Liguus population on Lignumvitae Key. In addition, an effort was made to examine the likelihood that Liguus are able to traverse great distances across seas by rafting. Lignumvitae Key was privately owned and, because of its isolation, was never developed commercially. The Key is now a Florida State Botanical Preserve which can only be reached by boat. It is unique in that the Key's hardwood forest, or hammock, has for the most part re- mained intact, with some trees well over 500 years in age. The height and diameter of these trees are matched by only a few stands of ham- mock left on the northern portion of Key Largo. The Key has an elevation of about 5 m making it among the highest in the 200 km long chain of Vol. 95(4) October 29, 1981 THE NAUTILUS 163 islands which extend from the southern tip of Florida to within about 130 km of Cuba. In addi- tion to its forest, the Key has a number of fresh water springs. METHODS Three study sites were established on the Key, each measuring 25 by 25 m. The first site was located on the east side of the Key about 300 m N.W. of the boat dock. The second site was just north of the main trail near the center of the Key, while the third site was on the west side of the Key, about 350 m N.W. of site 2. Dead snails were collected in order to deter- mine the areas and degree of mortality. Trees 4" or more in diameter were identified and counted. The age class of a snail was based on how many growing seasons the snail had ex- perienced. An annual growth line appears on the shell of each snail caused by the deposition of new shell at the thickened lip formed the previ- ous year. This interface is marked by a furrow which is often a different color. The annual growth line is quite prominent on most shells and usually can be distinguished easily from lines formed by interrupted growth during the growing season. Measurements of length were made with vernier calipers and rounded to the closest 1/10 of a mm. These measurements were taken in November after the snails had finished their seasonal growth. A Lincoln Index was conducted on 4 different occasions at each site to estimate the population density. For each index the snails received a distinctive mark. Individuals in age class 1 (snails in the first growing season) were not in- cluded in the recapture study for two reasons: (1) their small size precludes them from being observed and thus recaptured with the same probability as snails which are 2 years or older, and (2) snails in this age class are very fragile and might be subjected to a great deal of dam- age if included in the study. To examine the effects of exposure to salt water on Liguus two experiments were con- ducted using 90 snails in age classes 2 to 5 col- lected on North Key Largo. These snails were divided into 3 color groups of 30 individuals, each of which contained 22 lineolatus, 6 cas- taneozonatus, and 2 elliottensis. Snails in the first group were allowed to attach to 3 Dogwood branches, 10 to a branch. The branches were placed in a protected lagoon and the response of the snails observed. The branches floated in water about 1 m deep. Snails which fell off the floating branches were retrieved, rinsed with fresh water, and returned to Key Largo. The second group of snails was placed on a piece of plywood and left floating in the same Lagoon (on Plantation Key, Oct. 5, 1978) for 2 hours. The third group served as the control and was placed in a screen covered box on a dock within 4 m of the snails being tested. Both experiments were conducted under calm weather conditions, with only 2 cm ripples caused by light wind. A thin film of sea water covered the upper surface of the plywood board, but at no time were the board or snails submerged. RESULTS The plant survey indicated 16 tree species were distributed among the 3 study sites, with 8 species contributing over 60% of the individuals. Table 1 indicates the species composition for each site and the relative frequency of each tree TABLE 1. List of tree species found in each study site, and the % occurrence of trees with a 4 inch or greater diameter at each site. Percent Occurrence Tree Species • 1 » 2 » 3 - 1.6 Guaiacum soKctum Lignumvitae - - 3.2 Thrinax floridana Thatch Paljn - 3.2 ConoaarpiLS erecta Buttonwood - 3.6 - Cocos rmaifera Coconut Palm 21.8 - Swietenia mahogoni Mahogany 11.3 Amyrig elemifera Torchwood 1.6 - Gyminda latifolia Boxwood S.l Pithecellobium unguis-cati Cat's Claw 4.8 1.8 Mastiahadendron foelidissimwn Mastic 4.8 1.8 4.8 Pisonio dieaolor Blolly 8.1 1.8 6.4 Metopiim toxifeim Poisonwood 1.6 12.7 9.7 Fisaidia pisaipula Jamaica Dogwood 1.6 1.8 3.2 Ximenia americana Hog Plum 16.1 16.4 11.2 Coacoloba diversifolia Pigeon Plum 9.7 38.2 22.6 Bursera svnaruba Gumbo-limbo 34.0 1.3 34.0 Krugiodendron ferveum Iron-wood 62 55 62 Total number of trees 11 10 10 Number of tree species per plot 164 THE NAUTILUS October 29, 1981 Vol. 95(4) species at a site. Because of the dense canopy, little direct sunlight reaches the hammock floor during the warm wet summer, thus, most of the iloor is covered with leaf litter, bare soil or ex- posed coral rock. Plants in the understory occur near clearings and along trail cuts. Species in the understory associated with the study sites are wild coffee Psyehotra nervosa, white indigo Rnndia acuteata, crabwood Gymnnthes lucide, cheesewood Morinda royoc, and white stopper Eugenia axillaris. The average of the 4 Lincoln Indices for each site was determined to be 21, 28, and 25 individ- uals for sites 1, 2, and 3 respectively, with a pooled average of 24.7 individuals per plot. Thus, based on the size of a plot and the acreage of the island suitable as Liguus habitat, it is estimated that there are about 28,500 snails in the 2nd to 6th year age classes on the Island. A comparison of individuals in the hammock with those at the hammock edge indicated that the length of individuals of the same color form and age class inside the hammock was signifi- cantly less (t-Test, P>0.5) than those from the edge (Table 2). Though there was no statistical difference between the two color forms, individ- uals of simpsoni at all age classes averaged 1 to 3 mm larger than lignumvitae in the hammock, but the reverse was true at the hammock edge (Table 2, Fig. 1). Corresponding with the dif- ference in growth in the hammock, compared to the hammock edge, a difference in the distri- bution of age classes was noted, with the ham- mock edge having a greater proportion of 2 to 3 year old snails (58 to 65%) than the other por- TABLE 2. Average size as related to age class and occurrence in the hammock. A t-test was conducted between members of the same age class which occurred in different portions of the liammock. Central Hammock llaMTiock Edg e Color Form Age Class Average Length mm S.D. n Age Class Average Length mm S.D. n t Value lignimv. 1 27.1 0.8 10 1 31.2 1.7 10 2.81 Hgnwnv. 9 37.8 2.0 7 7 44.6 3.3 7 4.53 lignumv. 3 43.9 4.2 10 3 49.4 3.0 16 3.66 lignumv. 4 49.1 2.9 11 4 56.7 4.5 8 4.49 lignumv. 5 53.0 2.0 15 5 58.9 - 2 * lignumv. 6 55.1 3.1 3 6 61.0 - 7 * simpsoni 1 28.2 1.7 10 1 30.8 1.2 10 2.93 simpsoni 2 38.9 1.9 ]0 7 41.4 "> 1 8 2.34 simpsoni 3 46.0 2.3 13 3 49.7 3.3 12 3.07 simpsoni 4 50.5 2.9 23 4 55.1 2.5 6 3.19 simpsoni 5 54.2 3.1 19 5 57.8 2.1 5 3.95 simpsoni 6 57.7 0.5 3 6 60.2 1.7 5 * * t-test not conducted imless n was > 5. Vol. 95(4) October 29, 1981 THE NAUTILUS 165 60 55 5 0 4 5 E E 4 0 g" 3 5 01 to < 3 0 25 2 0 1 5 1 0 1 2 3 4 5 6 Age Class (yrs) FIG. 1. Average length of snails from the hammock edge and central portion of the hammock. Open symbols represent snails from the edge of the hammock, closed syynbols repre- sent snails from the central portion of the hammock. Triangles = simpsoni; circles = lignunivitae. tions of the hammock (33 to 41%) as indicated by Figure 2. Empty shells which were collected at the study sites during October were examined to determine the cause of death. Of the 61 dead siynpsoni found, 47.0% of the shells were intact and therefore placed into the unknown cate- gory, 27.7% of the damaged shells were attri- buted to mammals and 24.4% to birds. A total of 35 dead lignumvitae were found, 31.3% of which were placed in the unknown category, 22.8% were attributed to birds, and 45.7% to mam- mals. Considering the number of dead shells col- lected and the present population density, the shells must have represented the accumulation of a number of years. It is possible that damage may have occurred after the death of the snail, which resulted in attributing their death to other causes. From October 1978 to August 1980, 29 additional dead snails were found in the study sites (8 lignumvitae, 21 sinipwni). All 29 shells represented recent mortalities with 6 simpsoni and 2 lignumvitae appearing to have been predated, the remainder of the shells were intact. Observations were made in an effort to ex- amine the likelihood that Liguus are able to traverse great distances across seas on floating trees. In the first experiment 10 snails were placed on each of 3 cut Dogwood branches as described in the methods. Within 1 minute after the snails and branches came into contact with sea water, the snails released their grip from the branches and sank to the bottom. Thirty addi- tional snails which were placed on plywood and floated in the lagoon withdrew into their shells upon contact with sea water. All 30 snails died from their 2 hour exposure to a thin film of sea water within 36 hours. No mortality was ob- served among the control group. DISCUSSION Liguus become active in the spring following the first warm rains in April or May. It is at this time that the majority of the eggs deposited in the ground the previous fall begin to hatch. The snails feed almost exclusively on lichens, fungi, and algae which grow on the bark of trees. Al- though snails may be seen on any species of tree on the Key, they show a marked preference for smooth barked trees such as Jamacian Dog- wood, Blolly, and Mastic. Lysiloma and Dog- wood are two tree species preferred by Liguus in south Florida, but of the two only Dogwood occurs throughout the Keys. Lysiloma does not occur commonly any further south than Planta- tion Key, about 15 Km northeast of Lignum- vitae Key. During the course of the field work, five named color forms of L.fasciat us were found on the Key. The two endemic forms, simpsoni and ligiumivitae. constitute about 90% or more of the Liguus population. The remainder of the population consisted of two forms endemic to adjacent Lower Matecumbe Key, delicatns and suhcrenatus, both introduced to Lignumvitae KW; THENAl'TimS 50 Vol. 95(4) Age Class Ham moc k ( edge central FIG. 2. Agf c/f/.s-.s- distribution varied between the central portion and the edge of the hammock. The number of two-iiear-old individuals is unexpectedly low. and perhaps related to the unusually dry sutnmer and cold winter on the Key two years ago. Drought effects the hatch and sunnval of young snails. Key around 1955 by C. C. Von Paulsen, accord- ing to Mr. A. L. Jones. One specimen of the form dryas, also said to be introduced by Von Paulsen, was found. From April to August the snails remain active and rather mobile, especially during and after a rain. In July and August mating occurs and by early October the snails have come down out of the trees to lay their eggs. The construction of the nest and deposition of eggs requires 1 to 3 days, during which time 5 to 30 eggs will be deposited in the soil near the base of a tree. The eggs may vary in color from light to dark brown, and measure about 7.5x4.0 mm. Weber (1953) and Voss (1976) give additional information re- garding nest construction. The time of these events will vary from (jne Key to the next, as does the behavior of any one individual in a population. Population Size and Structure The frequency of thunder storms in the area decreases sharply in October, reducing the movements of the snails. It is at this time that the mark-recapture study was conducted. Four Lincoln indices were conducted at each study site, and the values averaged. The average estimates for the three sites were then pooled giving a value of 24.7 individuals per plot. Thus, based on 178 of the Keys 280 acres being suit- able Liguus habitat, the population estimate for the Key is about 28,500 individuals in the 2 to 6 year age classes. Frequently as many as eleven first year snails were observed in a study plot, and it is not known how many additional in- dividuals were hidden by foliage. Though no spe- cific data was collected on this age class in the mark-recapture study (for reasons given in the methods) they could have contributed an addi- tional 35 to 45% to the population. On Lignumvitae Key snails in their first or second growing season continued to grow until November, while older individuals stopped growing in September; for this reason measure- ments of length were taken in mid-November after all individuals had reached their maximum length. Individuals collected from the hammock edge were significantly larger than those from Vol. 95(4) October 29, 1981 THE NAUTILI'S KIT the middle of the hammock (Table 2). By plot- ting size against age class it becomes evident from the slope of the line that the major dif- ference is attributed to growth during the first two seasons (Fig. 1). A difference also exists between the two color forms with the average size of simpsoni exceeding that of lignumvitae in the central hammock but with the opposite being true along the hammock edge. Thus, it is possible that the two forms represent different biologically adapted types, as indicated by the differential growth rates under similar condi- tions. It should be noted that physically, condi- tions on the hammock edge are quite different than in the rest of the hammock. Typically the edge is less humid, has greater light penetra- tion, is exposed to winds, and has an abundance of food on the trees as compared with the inner portions of the hammock on this Key. Although the size difference between the two color forms from the same portion of the hammock was not always statistically significant, this may be due to sample size as the averages show a consistent difference (Fig. 1). An unexpected difference in age class distri- bution was found to occur between the ham- mock and the hammock edge (Fig. 2). In the cen- tral hammock the majority of the individuals were of the 4-6 age class, while along the ham- mock edge the majority were in the 2-3 age class. This difference might be attributed to a higher rate of survival among newly hatched in- dividuals because of greater food availability and less competition from older snails. Mature snails in this area must have a higher mortality rate, or a tendency to move away from the edge into the hammock. At least three observations on Lignumvitae Key differ sharply from those made by Voss (1976) on two Liguus populations on the mainland north of Homestead, and near Miami. Voss indicates that the growth rate of the snails is linear with respect to age. On Lignumvitae Key it is clear that the most rapid growth occurs in the first year and decreases at about the time individuals become sexually mature (3 or 4 years old). Thus, on the Key, shells of 4, 5, and 6 year old snails are not growing in length as fast as 1 year old snails (Fig. 1). Secondly, Voss found that almost all individuals die after apparently breeding only once at the age of 4. He found on- ly 1 individual which was 5 years old, and meas- ured perhaps only 3 individuals greater than 50 mm in length. On Lignumvitae Key about 21% of the Liguus population (2-6 yr.) were of the age class 5 and 6, with the vast majority of the individuals 4 years old or older being well over 50 mm (Table 2, Fig. 1). Thus Liguus on the Key exhibit a different pattern of growth, live sub- stantially longer (which results in more repro- ductive attempts), and grow considerably larger than those which Voss examined at Timm's and Brickell Hammocks. Voss failed to mention which forms of fasciatus he observed and measured during his study. My own observa- tions in Timm's Hammock revealed at least 14 named forms of fasciatus to be well established there in 1978. Although some of the observa- tions by Voss differ from the ones reported here, this is to be expected as he was dealing with different forms oi L. fasciatus living under biological conditions very different than those on Lignumvitae Key. Sources of Mortality All of the empty shells on the ground at the start of the study were collected and placed into 1 of 3 categories depending upon the condition of the shell. Of the 96 dead shells found, about 64% were simpsoni. with the remainder being lignumvitae. The type of damage differed markably between the two color forms, but the significance of this is not clear because it is not known how much of the damage observed oc- curred after the death of the snail. During the observations made in 1980, 8 lignumvitae and 21 simpsoni were found dead in the study area, 21 of the shells showed no sign of damage, but individuals of each color form had been attacked by raccoons. The damage caused to a shell by raccoons typically results in the upper portion of the shell being crushed and on occasion tooth holes may be seen on the remaining portion of the shell. Shells damaged by birds usually have a hole punched in the lower 2/3 of the shell, and it is more likely that a portion of the snail remains in the shell than if it were attacked by a raccoon. Shells which were placed in the unknown cate- 168 THE NAUTILUS October 29, 1981 Vol. 95(4) gon,' may have died in any number of ways, but in all cases the shell remained intact. Causes of death in this group might include predation by land crabs of the genus Coenobita. carniverous snails, ants, or old age. Although Eisner and Wilson (1970) suggest that body fluids offascia- tus may ser\-e to deture attacking ants. I have observed LiffuiLs being attacked and killed by the fire ant, Solonopsis geminata (Fab.) on 3 oc- casions. Thus. Liguus may be protected from some species of ants, but not all. Habitat Stability In a mature hammock, such as Lignum\itae Key, the Liguus population is probably rela- tively stable barring severe cUmatic conditions or other catastrophic events. A balance appears to have developed in which light intensity and moisture (influenced by canopy densitj- and cli- matic predictability) interact to influence the rate at which the snaUs' food regrows after be- ing grazed. This combined with the relative numbers of smooth-barked trees must deter- mine the over-all carrj-ing capacity'. An ex- amination of the Dog^vood trees on the Key reveals those in the central hammock to be polished or almost so. This condition results from the continual scraping of the radula on the bark of the trees over a great many generations. A tree which has been polished by Liguus ap- pears quite different from one which has been recently occupied and merely had the majority- of the food eaten off the bark. In hammocks disturbed by fire where the Liguus population was sharply decreased, the food regrows rapidly due to increased light and reduced grazing pressure by the snails. During the second and third years following a fire, large individuals are found. These have a high reproductive success such that the density may exceed that reached prior to the fire. As a result of the population in- crease, the available food is soon consumed. This caus^-'s a shortage for most members of the population which results in stunted growth and lower fecundity. In time the lower fecundity and lack of food results in a general decline in the population. Numerou.s oscillations may follow as the balance is established between food avail- ability and the density ot Liguus. Based on the mean size of indi\iduals on the Key and the pop- ulation density, the Lignumxitae Key Liguus population is probably oscillating about a point near the present carrying capacity of the island. Thus, this population is probably relatively stable in relationship to the conditions within the hammock as it presently exists on the Key. Dispersal of Liguus Pilsbr\\ (1946) stated that "All naturalists who have considered the subject agree that our Liguus were derived from Cuban stocks of the polymorphic L. fasciatus (Miiller), brought to Florida sealed to floating trees and cast ashore by high winds or hurricanes." Although the ori- gin of our Liguus may not be in dispute, the means by which they arrived here is by no means clear. The mode by which Pilsbry sug- gested that L iguus arrived in Florida cannot be discounted, but the likelihood of an event such as he described appears to be much lower than one might expect. AestivatingLi^i/^ do form a tenacious seal by which they attach themselves to a tree during the winter, but the hurricane season is during the summer and fall while the snails are active and not in aestivation. In addi- tion, the mucus which seals the snail softens and becomes non-adhesive when moistened for ex- tended periods. To examine the possibility' that non-aestivat- ing snails could sunive the journey which Pilsbrj- described, several tests were run. First, it was obsen'ed that the density of some trees, such as Lignum\itae and Ironwood, is greater than that of sea water and therefore they do not float. Other tree species, such as Gumbo-limbo, Dogwood, and Poisonwood, barely remain afloat in calm water. Thus, it appears that many species of trees in the hammocks are not suitable as rafts for Liguus. None of the 30 snails on Dogwood branches remained attached for more than a minute after the branches were placed in sea water. The snails placed on a board, which was floated for 2 hours, never came into contact with water greater than 3 mm deep, and were usually out of the water, but moist. Again, the snails withdrew into their shells upon contact with sea water, Vol. 95(4) October 29, 1981 THE NAUTILUS 169 but this time the shell remained setting on the flat surface of the board. No individuals exposed to these conditions during the 2 hour test were alive 36 hours later. This sensitivity to sea water may explain why many of the forms of Liguus endemic to the Keys occurred on only one or two Keys, while forms in the Everglades tend to be more wide- spread. It appears that aestivating or non-aesti- vating snails have an exceedingly low probabil- ity of surviving a 130 Km trip in a hurricane to reach the southern-most portion of Florida. ACKNOWLEDGMENTS I wish to thank Mr. Archie Jones and Dr. Barry Roth for reviewing the manuscript, and Dr. Roy Snelling for identifying the ants. I would also like to thank Kevan O'Kane, and Jim Stevenson of the Florida Department of Natural Resources for their cooperation, and Steve Sparks and Kevin Sunderland for assistance. Special thanks to park ranger Ms. Jeanne Parks for all of her assistance and cooperation. LITERATURE CITED Davidson, T. 196.5. Tree .snails, gems of the Everglades. Nat. Geogr. Mag. 127:372-387. Doe. M. F. 1937. Tree snails of south Florida. Nature Mag. 29:82-84. Eisner. T. and E. 0. Wilson. 1970. Defensive liquid dis- charge in Florida tree snaWs (Liguusfaseiatus). The Nauti- lus 84:14-15. Jones, A. L. 1954. How Florida Tree Snails Live. Everglades Nat. Hist. Mag. 2:59-62. Pilsbrj', H. A. 1946. Land Mollusca of North America (north of Mexico). Acad. Nat. Sri. Ph Had. Monogr. No. 3, Vol. 2. pt. 1, p. 37-102. Voss. R. S. 1976. Observations on the ecologj- of the Florida tree snail Liguus fasriatus (Muller). The Nautilus 90:6.5-69. Weber, J. A. 1953. Nests of the Florida tree snail. Ever- glades Nat. Hist. Mag. 1:63-65. A NEW SPECIES OF VOLUTOCORBIS (VOLUTIDAE) FROM SOMALIA Harald A. Rehder National Museum of Natural History Smithsonian Institution Washington, D.C. 20560 Through the kindness of Dr. Harry G. Lee of Jacksonville, Florida, I received for examination a small series of a species of Volutocorbis from Somalia. I recognized immediately that the specimens were unlike any described species of the genus. With Dr. Lee's permission I am describing this species as new and am pleased to name it in honor of Mrs. Rosavittoria Todaro, from whom Dr. Lee received the specimens. They were col- lected by Abdulkadir Ma'allin "Javane", from whom Mrs. Todaro obtained the specimens. Volutocorbis rosai-ittoriae new species (Figs. 1-5) Description: Shell of medium size for genus. heavy, biconic, with the spire sharply conical, about V4 total length or slightly more. Proto- conch mamillate. consisting of about IVs smooth, rounded whorls, the top sometimes ob- liquely flattened. Postnuclear whorls 5V4-6, first one with axial ribs that become nodulose below suture after first "4 whorl, with a second spiral row of nodules, separated from the first by a rounded groove; the subsutural row of nodules in later whorls margins a channeled subsutural shelf and may divide and form an upper flat- tened, less nodulose cord; in later whorls the number of spiral rows of nodules increases with the addition of finer spiral cords, the number of such spiral elements numbering about 45 in paratype #3; the number of axial ribs and riblets 170 THE NAUTILUS October 29, 19S1 Vol. 95(4) FIGS. 1-5. Volutocorbis rosavittoriae n. up. x 1. 1, Hulofype. dorsal vieu: 2, Hutotype. apertural rieu: 3, Paratype nu. 1. 4, Pnratype no. 2. 5, Paratype no. 3. also increases so that in the same parat^^^e there are 16 riblets in the first postnuclear whorl and about 50 in the last whorl. The last whorl is usually slightly angled at the shoulder by a strong row of pointed nodules, and the entire surface is rendered rough and filelike by the numerous spiral cords and threads made finely nodulose by the crowded axial riblets. The color is pale tan or dark straw-color with white spiral lines or bands. Aperture narrow, pointed at both ends, outer lip broadly thickened inside with 16-22 teeth of various sizes that extend as spiral ridges into the aperture; parietal callus thin, margined above and on lower half, with 7-10 spiral folds on thickened internal lower half, the lowest fold usually strongest; lower part of outer lip flattened near broad, open siphonal canal. Range: South coast of Somalia from off Kisi- mayu (Chisimaio) to Brava. Type locality: Off Kisimayu, southern Somalia. No. of Height Width Whorls 50.75 22.9 5% 50.45 22.9 6 40.25 20.2 5'/, 39.15 19.4 5 'A Measurements (in mm): Holotype USXM 784653 Paratype #1 USNM 784654 Paratype #2 Colin. H. G. Lee Paratype #3 USNM 784654 Remarks: This species is distinct from other known species of Volutocorbis in possessing a stout, thick shell with strong, fine spiral and ax- ial sculpture. In size, general shape, and in the thickness of the outer lip it is closest to V. semirugata Rehder and Weaver, 1974, but that species is much smoother, with more strongly shouldered whorls. Since receiving the four specimens that form the basis of this description, Dr. Lee has learned that this species has been collected in some numbers off Brava on a species of Xenophora. probably pallidula (Reeve). Of 100 specimens of the latter species 29 had specimens of Volutocor- bis rosavittoriae affixed to them. NOW AVAILABLE MONOGRAPHS OF MARINE MOLLUSCA, no. 2. The Family Buccinidae. Part 1; The Genera iVa^- saria, Trajana and Neoteron. 50 pp. By Walter 0. Cernohorsky. $7.50. Postage free if order is ac- companied by payment. Foreign subscribers please add $1.00 for postage. American Malacologists, Inc., P.O. Box 2255, Melbourne, FL. 32901-0328. U.S.A. Vol. 95(4) October 29, 1981 THE NAUTILUS 171 TWO NEW SPECIES OF ACANTHOCHITONA FROM THE NEW WORLD (POLYPLACOPHORA: CRYPTOPLACIDAE) G. Thomas Watters Department of Zoology' University of Rhode Island Kingston, Rhode Island 02881 A systematic revision of the New World Cryp- toplacidae has revealed the presence of two new species: Acanthochitona imperatrix (command- ing chiton) from tropical west America and Acanthochitona andersoni from southeast Florida and the Caribbean. Because of the wide- spread confusion in the literature concerning this family, additional notes on related species have been extracted from the revision to help clarify the taxonomic position of the species in- volved. Abbreviations used in the text: AMNH- American Museum of Natural History, New York. ANSP- Academy of Natural Sciences of Phila- delphia. DMNH- Delaware Museum of Natural History, Greenville. MCZ- Museum of Comparative Zoology, Har- vard University. USNM-U.S. Museum of Natural History, Washington, D.C. Acanthochitona imperatrix new species (Plate la, b, c; Plate 4b) Description: Holotype 8.9 mm in length, curled. Tegmentum of intermediate valves about twice as wide as long, flattened, not carinate. Beaks prominent. Jugum very wide, flat, smooth, and distinctly raised above the latero-pleural areas. Jugal macresthetes widely spaced, arranged in longitudinal rows, each associated with 0-2 micresthetes. Latero-pleural areas sculptured with numerous teardrop- shaped, close-set pustules, each moderately elevated and concave. Each pustule bears one centrally located macresthete. 0-5 micresthetes (commonly 0) accompany each macresthete and are generally confined to the area anterior to 'Present address: Museum of Zoology, Ohio State Univ., Columbus, OH 43210. the macresthete. Mucro central and prominent with a concave postmucronal slope. Tegmentum uniformly peach-colored, the jugum lighter. Alternating spots of cream and maroon occur along the posterior borders of the valves and flank the jugum on the holotype. Apophyses extensive. Slit formula 5-1-2. Ar- ticulamentum colored cream, tinged with green towards the beaks. The dorsum of the girdle is velvety, armed with dense, very minute spicules. These spicules are monomorphic (i.e. -composed of one tj^pe of element as opposed to bimor-phic, composed of two distinct types of elements), round in cross- section, smooth, and slightly bent. Girdle dor- sum peach-colored, ventral side slightly darker. Marginal fringe and sutural tufts well- developed, composed of numerous long, slender spicules. Type locality: 8 fathoms (14.6 m) off San Diego, California; lat. 24°22'30" S, long. 110°19'30" W; taken with tangles on broken shell bottom, April 30, 1888, by the U.S. Fish Commission. Holotype: USNM 218762. Para- types: USNM 225346 - Sta. 2826, 9.5 fathoms (17.4 m) off La Paz, Baja California Sur; lat. 24°12'00" S, long. 109°55'00" W; taken with oyster dredge on shelly bottom, April 30, 1888, by the U.S. Fish Commission. ANSP 153484 -Seymour Bay, Isla Santa Cruz (Indefatigable Island), Galapagos Islands, by Pinchot Expedi- tion, Pilsbry. Range: Subtidally to at least 17 m, from southern California to the Galapagos Islands. Remarks: A. G. Smith and Ferreira (1977) il- lustrated and described a specimen of this species (ANSP 153484) but did not name it. Their specimen was composed of a head, tail, and three intermediate valves without the gir- dle. The specimen is labeled as 'A. galapagana Pils. MS, A. G. Smith TYPE". This name was 172 THE NAUTILUS October 29. 1981 Vol. 95(4) PLATE 1. Figs, a, b, and e: Acanthochitona imperatrix new species. Paratope ANSP 153i8i, Seymour Bay, hla Santa Cruz. Galdpago's Islands, (a): valve ? VII. 3.9 mm diameter, (b): valve VIII, 2.8 mm diameter, (c): valve VIII. profile. Fig. d: Acanthochitana communis (Risso. 1826). USXM 218733. Tierra del Fuego. Argentina; calve VII, 5.2 mm diameter. Fig. e, f, and g: Acanthochitona angelica Dall, 1919. AMNH 7U~13. Maria Mngdalena Island. Tres Marias hlawlx. (e): valve VII. 3.8 mm diameter, (f): valve VIII. 2.7 mm diameter, (g): ■ nlri- VIII. profile. Fig. h, i, and j: Acanthochitona avicula (Carpenter. 186U), AMNH 130977. Agua de Chale. Buj'j Culij'omia. Mexico, (h): valve VII. 3.J, mm diameter, (i): valve VIII. 2.3 mm diameter, (j): valve VIII, profile. never introduced and Dr. Ferreira (written comm.) is not familiar with it. Subsequently I located two conriplete specimens at the U.S. Na- tional Mu.seum (TSNM 225346 and 218762), the latter of which I nave desi^ated as holotjpe. Acanthochitona imperatrix is one of several species in a New World complex composed of forms characterized by broad, rectangular, in- termediate valves bearing teardrop-shaped pustules and a centrally located, prominent Vol. 95(4) October 29, 1981 THE NAUTILUS 173 mucro. In addition to A. imperatrix. the com- plex contains A. angelica Dall, 1919, A. avicula (Carpenter, 1864), A. communis (Risso, 1826), and A. spiculosa (Reeve, 1847). A second com- plex, composed of A. astriger (Reeve, 1847), A. exquisita (Pilsbry, 1893a), A. hemphilli (Pilsbry, 1893a) (rhodea (Pilsbry, 1893a) is this species), A. hirudin ifonnis hirudiniformis (Sowerby, 1832) (coquimboensis (Leloup, 1941a) and tabo- geyisis A. G. Smith, 1961, are this species), and A. kirvxiiniformis peruviana (Leloup, 1941a), is differentiated by having long, pentagonal valves, oval to teardrop-shaped pustules, and a low, posteriorly acentric mucro. The third New World complex will be discussed under the fol- lowing remarks of Acanthochitona andersoni new species. The superspecies that contains A. imperatrix antedates the closing of the western Tethys Sea and probably stems from A. communis or its im- mediate ancestor. Acanthochitona communis (pi. Id; pi. 4a) is a widely distributed species throughout the Mediterranean, the eastern Atlantic from Spain to Great Britain and the Azores (Malatesta, 1962), the Cape of Good Hope and the Falkland Islands (Leloup, 1941a), Tierra del Fuego (USNM 218733). and the southern Caribbean (as A. bonairensis Kaas. 1972). The dorsal girdle elements of A. com- munis are bimorphic while those of .4. impera- trix are monomorphic; furthermore, A. com- munis does not possess the very wide, flat, distinctly raised jugum of A. imperatrix. Acanthochitona angelica Dall, 1919. (pi. le. f, g; pi. 4e) differs in having bimorphic girdle elements, both of which are bent and striated; those of .4. imperat7-ix are straight and smooth. The jugum of A. angelica may be longitudinally striated and is never as wide as in A. impera- trix. A. G. Smith (1977) inexplicably sxTiony- mized A. angelica with .4. avicula despite ob- \ious differences between the two species and A. angelica has not been recognized as distinct in recent years (Putnam, 1980, and Kaas and Van Belle, 1980). The dorsum of the girdle of .4. angelica is velvety, composed of minute spicules, while those of A. avicula are coarse and thorn-like. In addition, the pustules of A. angelica are never as large and elongated as those of A. avicula. A. G. Smith and Ferreira (1977) introduced A. jacquelinae, a sjTionym of A. angelica. Acanthochitona avicula (Carpenter, 1864) (pi. Ih, i, j; pi. 4c, d) differs from A. imperatrix in possessing a striated jugum and large, bent, distally striated spicules among the smaller, smooth elements on the dorsum of the girdle. Acanthochitona avicula variety diegoensis (Pilsbry, 1893b) is a common variant; the lec- tot\-pe, herein designated, is ANSP 349330 from San Diego, California (pi. 4d). Acanthochitona spiculosa (Reeve. 1847) (pi. 2a, b, c; pi. 4f, g) from the Caribbean and south- eastern U.S. also has a striated jugum and bent dorsal elements. The A. pygmaea of Abbott (1954, 1974), Kaas (1972), Warmke and Abbott (1964), Kaas and Van Belle (1980). and others, is A. spiculosa. Acanthochitona pygmaea (Pilsbn,', 1893b) is based upon a juvenile of A. spiculosa: the lectot\'pe, herein designated, is ANSP 35783 from Key West. Florida (pi. 4g). The "spiculosa" of these same authors (and of most collections) is A. astriger. a common West Indian species which has been confused with A. spiculosa ever since E. A. Smith (1890) first misidentified his specimens. Acanthochitona astriger (pi. 2d: pi. 4h) never possesses a striated jugum and has longer, more pentagonal valves than A. spiculosa. The complicated synonymy of these two species will be presented at a later time. Synonymy: Acanthochitona species? A. G. Smith and Ferreira. 1977. rWipcr 20:82. 97. fig. 22. Acanthochitona andersoni new species (Piate 2e, f. g; Plate 4i) Description: Maximum size 12 mm in length. Tegmentum of intermediate valves longer than wide, pentagonal in outline. Beaks prominent. Jugum wide, smooth except for growth lines. Jugal macresthetes widely and irregularly placed, generally absent from the central por- tion of the jugum. Each macresthete is accom- panied by 1-5 micresthetes. Mucro posteriorly acentric, ven,- prominent; postmucronal slope steep and concave. Lateropleural areas sculp- tured with widely spaced, convex, "D"-shaped pustules which radiate from the beak. Each 171 THENAl'TILrS October 29, 1981 Vol. 95(4) iL__Ij F'LATK 2. Fiys. a, b, , Watters collection, Bahia deKino, Sonora. Mexico, (h): valve VII, 2.!, mm diameter, (i): valve VIII, 1.8 mm diameter, (j): valve VIII, profile. pustule bears one macresthete located towards the prepustular edge. The 2-7 micresthetes per pustule are limited generally to the prepustular slope. Tegmentum mottled brown, yellow, green, or uniformly white; pustules may be col- ored differently from the rest of the tegmen- Uim. One paratype (DMNH 95383) is uniformly blackish-brown with occasional white pustules. Apophyses moderately extensive. Slit formula 5-1-2, with interslits in some specimens. Vol. 95(4) October 29, 1981 THE NAUTILI'S T Articulamentuni translucent white, the color of the tegmentum showing through. The entire girdle is velvety, armed with dense, bimorphic spicules on the dorsum. Both types are flattened in cross-section, bent, and smooth, but differ in size. Girdle variously colored green, white, dark-brown, tan, or mottled with these colors. Sutural tufts and marginal fringe well- developed but composed of only a few long, stout elements colored translucent white. Type locality: Sta. 2, rocky cove, south shore of point, 1 km south of Calliaqua, St. Vincent, Lesser Antilles. Holotype: ANSP 332171. Paratypes: ANSP 220834 - 30 fathoms (54.6 m), on wreck, off Destin, Florida; ANSP 220833 - 30 fathoms (54.6 m), off Boynton Beach, Florida, Bales; Bullock collection - West Summerland Key, Florida; USNM 103424 - Key West, Florida, from U.S. Fish Commission; USNM 181248 - Key West, Florida, April 15-27, 1884; USNM 663398 - Key West, Florida, Weber; MCZ 204125 - Dry Tortugas, Florida, 1940, E. Koto; USNM 735327 - Sta. 52-60, on coral, center of Nicchehabin Reef, East Allen Point, Ascension Bay, Quintana Roo, Mexico; Bredin - Smithson. Inst. Expedition, April 10, 1960, Rehder & Bousfield; USNM 736249 - Sta. 85 & 95, Suliman Point, Ascension Bay, Quintana Roo, Mexico; Bredin - Smithson. Inst. Expedi- tion, April 17 & 19, 1960, Schmitt et al.; USNM 736058 - Ascension Bay, Quintana Roo, Mexico; Bredin - Smithson. Inst. Expedition; Bullock collection - Galeta Point, Canal Zone; ANSP 325808 - 1 mile west of Haulover, North Bimini, Bahamas; ANSP 325864 - 1 mile east of Turtle Rocks, southwest of concrete ship, 18 feet (5.4 m), Bimini, Bahamas, 1957-58, Robertson; DMNH 95383 - 10.6 m on Strornbus gigas, Pic- quet Rocks, Bimini, April 17, 1973, Watters; MCZ 238906 - Goat Key, Andros Island, Bahamas, Patterson; MCZ 390 - Tobago Island, Clarke; Bullock collection - St. Jorisbaai, Curasao. Range: Subtidally to at least 55 m, from Quin- tana Roo to southeastern Florida and the Bahamas, the Lesser Antilles, and the Nether- lands Antilles. Remarks: This new species is not uncommon in collections but is often misidentified as other species, particularly as A. pyginaea <=A. npicu- losa) and A. hale^^ae Abbott, 1954. It is part of distinct complex containing A. arragonites (Carpenter, 1857) and A. balesae. The species of this complex are recognized by the vermiform body and convex, "D"-shaped pustules. All other New World Acanthochitona have concave, tear- drop-shaped or oval pustules. Acanthochitona andersoni is closely related to A. arragonites (pi. 2h, i, j; pi. 4k), its cognate from the eastern Pacific, but can be differenti- ated by the dorsal girdle elements: in A. ander- soni they are bimorphic, both types being flat- tened in cross-section, smooth, and bent, but of two distinct sizes; in A. arragonites they are monomorphic, round in cross-section, finely rib- bed, and bent. Acanthochitona balesae (pi. 3a, b, c; pi. 4j) dif- fers from A. andersoni in having the dorsal elements monomorphic, flattened in cross- section, strongly ribbed, and bent. The pustules PLATE 3. Figs, a, b, and c: Acan- thochitona balesae .4 WJ xpeciea colli'i-tcd nt Luke McConaughy. Keith County. AVA;vi.sA'«. Collection site nuTiber Specimen identification number Species Length Length (g.) Composition of substrate Depth of collection Se". ati ve Turbidity (i.e. visibility) (m. ) 1 — — — - Mud Bottom 4 < 1 Z — -- -- -- Mud Bottom 3 < 1 3 -- -- -- -- Mud Bottom 3 - 4 < 1 4 HDBl A. qrandis grandis 0.150 278.5 Fine Sand/ 3 - 5 5 - 7 MDB2 A. grandis grandis 0.144 270.5 Silt with MDB3 A. grandis grandis 0.155 370.0 large rocks HDB4 A. grandis dakota 0.160 386.0 5 JEF15 A. grandis dakota 0.132 209.0 Fine Sand/ 5 - 7 5 - 7 MDB16 A. grandis grandis 0.086 54.3 Silt with 6 ~ -- — — large rocks Sand/Silt 4 - 7 ottom (usually under 3 m). The substrate of .ake McConaughy is sand, but a thin layer of ilt is found in the deeper waters toward the am. 12 of the clams were found on the sand- ilt; only 4 clams (A. g. grandis and A. im- ecillis) were collected on sand-rock substrates Fable 1). Of the larger clams collected (MDB4, JEF6, [DB8, JEF9) the majority were found in deeper -aters located in the coves at the base of the im (Fig. 1). This area should be the most stable 1 terms of water level fluctuations due to the LCt that it is closer to the dam and should lerefore maintain a higher, more constant level " water. No Anodonta individuals were found in depths ss than 2 m, despite searching at least 400 m^. his result is confirmed by area divers, who re- ported seeing 70 additional clams, all in depths of 3 to 5 m. Therefore, Anodonta appears to be confined to the perimeter waters (3-5 m deep) of this reservoir. Since the study was conducted in August of the year in which the lake was high until quite late in the season, it is likely that these depths represent early summer level's, and that minimum depths of perhaps slightly under 2 m are experienced at those sites only at lowest storage. This suggests that Anodonta is uncom- mon in the shallow (rarely 2 m deep for any ex- tended period of time) North Platte River.' No other mollusks were observed; presumably they are rare or absent. ACKNOWLEDGMENTS I wish to thank Dr. K. Keeler for her support and direction in this project; J. Ferguson, my diving partner; Dr. D. H. Stansbery for identi- fying specimens; and J. Palmer for editing and tyT3ing this manuscript. A special thanks to the Cedar Point Biological Station operated by the University of Nebraska for the use of its facilities and equipment during this project, and especially to its Director, Dr. J. Janow, Jr.,' and his wife, Karen, for the most memorable sum- mer of my life. LITERATURE CITED Burch. J. B. 19T3. Biota of Freshwater Ecosystems. Identi- fication Manual #11 Freshwater Unionacean Clams (Mol- lusca: Pelecv-poda) of North America. U.S. Enmromnental Protection Agency Publication. Washington, D.C. Central Nebraska Public Power. 1965a. Central Nebraska District, Lake McConaughy. Cevtral Public Power Dis- trict Publication. North Platte, Ne. Central Nebraska Public Power. 1965b. Statistics of the Lake McConaughy Reser\'oir. Central Public Power Dis- trict Publication. North Platte. Ne. Frierson, L. S. 1910. Description of a new species of Ano- donta. The Nautilus 23(9):113-114. McCarraher. D. B. 1977. Nebraska's sandhills lakes. Ne- braska Game and Parks Commission, Lincoln, Ne. Nebraska Game, Forestation, and Parks Commission. Fish Stock- Pu'corck. 1958-1979. North Platte Regional Office North Platte, Nebraska. Pennak, W. 1958. Study of Freshwater Invertebrates. Uni- versity of Colorado Press, Denver. Taylor. M. W. 1979. Modelling the influence of eutrophica- tion on the cold-water fishen,' habitat of Lake Mc- Conaughy, a "two-story" reservoir. Nebraska Game and Parks Commission Publication. Lincoln, Ne. 184 THE NAUTILUS October 29, 1981 Vol. 95(4) PROTANDRY WITH ONLY ONE SEX CHANGE IN AN EPITONIUM (PTENOGLOSSA) Robert Robertson Academy of Natural Sciences Nineteenth and the Parkway Philadelphia, PA 19103 ABSTRACT KefHirts conflict on whether ptenoglossam'i undergo more than one sex change, although since 1926 they were always reported (with few supporting data) to be protandric. Small individuals of the West Indian wentletrap Epitonium albidum (Orbigny, lBi2) (shell length <8 mm) were found, to be males (with spermato- zeugmata in their gonads), and large individuals (shell length >7 mm) were females (with oocytes and ova). Hermaphroditic individuals ranged in shell length from 5 to 8 mm.. The data support the idea ofprotandry with only one sex change in E. albidum. Males and females attain larger sizes in the British Virgin Islands than at Barbados. The Epitoniidae ( = "Scalariidae" or "Scalidae") and Janthinidae, two ptenoglossan families, have at various times been considered to have separate sexes, or to be simultaneous herma- phrodites or to be protandric hermaphrodites. Cuvier (1808:129) believed that the sexes are separate in Janthina. but Quoy and Gaimard (1832:247) believed Janthina to be her- maphroditic. Pruvot-Fol (1925), who studied histologic sections of two Janthina animals. thought that they are simultaneous hermaphro- dites and that they possibly self-fertilize. Ankel (1926:196) stated that "Scala" [ = Epito- nium] and Janthina are protandric. The meager data published subsequently (Table 1) support this conclusion, but there is disagreement on whether there is more than one sex change. Fretter and Graham (1962:377-378) summa- rized the situation well. Ankel (1936:149) stated that in "Scala"! = Epi- TABLE 1. Authors since Ankel (1926) who have coticluded that pteyioglossans are protandric. Author Species studied^ Only one sex change More than one sex change Ankel, 1930: 496-502, fig. 3 Ankel, 1936: 149-150, fig. 128 Laursen, 1953: 8-14 (Jraham, 1954 Bulnheim, 1962: 302-304 Bulnheim, 1968: 234 Breyer, 1980 Robertson, 1981 Robertson, this paper Janthijui pallida Epitonium ctathrus Janth ma spp. J(Uilhin(i janthina Upalia funiculata Efiiton I N ni linctuni Epitonium liiiclutn Epitonium millecostntum Epilon ium albidum + + + 'Nomenclature ijroughl up-to-date. Vol. 95(4) October 29, 1981 THE NAUTILUS 185 toninmj clathrus (Linn., 1758) there is sex rever- sal accompanying each breeding season (it is not stated when the breeding season occurs, or how long the Epito7iium lives). The purpose of this paper is to determine from a large series of specimens whether the West In- dian wentletrap Epitonium. albidum. (Orbigny, 1842) is protandric and whether it undergoes more than one sex change. MATERIALS AND METHODS Epitonium. albidum. a symbiont with the ac- tiniarian Stoichactiit heliunthus (Ellis and Solander, 1786) (Robertson, 1963:52-53), was studied at Virgin Gorda Feb.-Mar. 1972 and Barbados Mar.-April 1980. The shell length of each specimen was recorded, and the shell was cracked or dissolved (in weak hydrochloric acid or in Bouin's solution). Gonads were examined with a Wild dissecting microscope at 50x . Sper- matozeugmata (ciensely packed in the gonad, es- pecially to the right of the stomach) and oocytes and ova could readily be distinguished. Individ- uals termed hermaphroditic had spermatozeug- mata proximally in the gonads and oocytes and ova distally. RESULTS The data are given in Fig. 1. Ninety-three in- dividuals were sexed-39 from the British Vir- gin Islands and 54 from Barbados. Fifty-three animals, ranging in shell length from 1 to 8 mm, were males, and twenty-nine animals, ranging in length from 7 to 16 mm, were females. Eight animals, ranging in length from 5 to 8 mm, were hermaphrodites, and three additional animals, ranging in length from 2 to 4 mm, were im- mature. An animal 8 mm long was seen to shed spermatozeugmata and was later sexed as a female (it was categorized as a hermaphrodite). The sex ratio was 59% male, 9% hermaphrodite and 32% female. The largest Barbados males were 6 mm long, while the largest British Virgin Island males were 8 mm long. British Virgin Island females ranged up to 16 mm; one Barbados female was 14 mm, and the others were 11 mm or less in length. (According to Clench and Turner (1951: is- 14- 13- 12- 11- 10- 9- 8- 7- 6- 5- 4- 3- 2- 1- 0- 1- 0- Mill . ; s 9 10 ■ I ■ ; I 9 10 n 12 13 14 IE I 5 S ; J mm 5 = 93 I 1 2 3 4 5 6 7 « mm ^. H immature 2 3 4 mm SHELL LENGTh FIG. 1. Shell lengths vf imninture. itiale, hi-nnaphriiclilp and frmale itidiridiials (j/'Epitonium idbkiumj'rotii Barbadiis and Iht' British \'irqtn Isliinds. 260-261), E. albidum attains a length of about 21.5 mm.) CONCLUSIONS The data given here on Epitonium albidum support the concept that at least this species is strictly protandric, that is, it first becomes male and later becomes a female between shell lengths of 5 and 8 mm. All the individuals longer than 8 mm were females. There is no evidence that these females ever change back into males. The proximally (anteriorly) located spermato- zeugmata of the hermaphroditic individuals in- dicate that these were changing from the male to the female phase and not vice versa. The above conclusions are consonant with those on Janthina by Ankel (1926, 1930) and Graham (1954), and other species i)i Epitonium by Breyer (1980) and Robertson (1981). The statements by Ankel (1936) and Bulnheim (1962, 1968) about epitoniids alternating their sex more than once require substantiation. 186 THE NAUTILUS October 29, 1981 Vol. 95(4) Male and female Epitnnium nlbidum attain larger sizes in the British Virgin Islands than at Barbados. ACKNOWLEDGMENTS I am grateful to Dr. Finn Sander, Director, Bellairs Research Institute of McCJill University, Barbados, for the provision of excellent facili- ties. The following kindly criticized the manu- script: Dr. George M. Davis and Virginia Orr Maes. LITERATURE CITED Ankel, W. E. 1926. Sperrtiiozeugmenbildung durch atypische (apyrene) und typische Spermien bei Scala und Janthina. Verhandl. Deutsch. Zool. Gesellsch.. 31 Jnhresi-ersamml. Kiel, Zool. Anzeiger Supplhd. 2: 193-202. 1930. Die atypische Spermatogenese von Jan- thina (Prosobranchia. Ptenoglossa). Zeitschr. Zellforsch. mikroskop. Anal ll(3-4):49 1-608, pi. 6-7. 1936. Prosobranchia [in] G. Grimpe and E. Wagler (eds.), Die Tierwelt der Nord- und Ostsee IX. bi, Lief. 29:1-240. Leipzig, Alpleurun carinatus Dall. 1927:11 (non Leach, 1847, male name; non Leach, 18.52). Type locality: Eastport, Maine [44° 54' N, 67°b0' W]. Holotype: (USNM 225149). Original description: "Shell rather large . . . yellowish white, densely covered with minute pustules which are obscurely arranged concen- trically to the mucro of the posterior valve, radially on the anterior valve and longitudinally on the intermediate valves; back subcarinate, the angle about 70°; eaves projecting, the inser- tion plates of the terminal valves not split but radially rugose, of the intermediate valves en- tire; girdle narrow, densely pilose, with ex- tremely fine close minute spinules, with alter- nating darker and lighter patches; central, jugal and lateral areas not defined; length in dry, curved condition about 35, diameter 9; height, 12 mm." (Dall, 1927:11). Expanded Description: The holotype of Lepidoplen7~iis carinatus Dall, 1927 (USNM 225149) is accompanied by a museum label which reads "Eastport / type / 1870 / Maine / Verrill," with question marks pencilled in by unknown hand after the words "Eastport" and "Maine." Specimen preserved dry, tightly curled; all valves broken, mostly longitudinally, with loose fragments of valves i, ii, iv, and v. Uniform cream color. Strongly carinate. Lateral areas obsoletely defined; tegmentum sculptured with vermicular, low profile rugosities disposed longitudinally in central areas, concentrically in valve i, postmucro area of valve viii, and lateral areas of intermediate valves (Figure 1). Valves Vol. 95(4) October 29, 1981 THE NAUTILUS 191 Fl(j. 1. Holutype y/ Lamir.oplax dalli iKans. i:i:>7). ChiKe-uii oj valves vi and vii to show tegmental sculpture. remarkably heavy, up to 800 y^m in thickness on valve iii. Insertion plates well developed in the anterior and intermediate valves, but limited to a ridge in the posterior valve (Figure 2), without slits or teeth, but with tluted rugosities on the outer surface (Figure 3). Sutural laminae rela- tively large, separated by a well defined sinus. Girdle pilose in appearance, covered uniformly with juxtaposed spicules (Figure 4), mostly straight, many broken (Figure 5) measuring up to 400 piva in length, 30 yun in thickness; under- surface covered with imbricated, tlat, trans- parent, lanceolate scales, about 120x15 ]xm in dimentions (Figure 6). Gills short, posterior. Radula, still in place, not examined. Remarks: Laminoplax dalli is known only from the tj'pe specimen. Although Dall (1927) in- Uj. 2. Holotype o/' Laminoplax dalli iKaas. 1957). Close-up I posterior valve to show (arrow) side vie^v of insertion •lute, here limited to a ridge. FIG, 3. Holotype o/ Laminciplax dalli /A'rm.s. ;■/.•],-;. Clusi-uji of fragment of anterior valve to .s/xi/r tegmental sralptun. and insertion j)late with its Jhited rugosities. _i 10 mi FIG. 4. Holotype o/ Laminoplax dalli iKans. iy.',7). Girdle spicules at junction of ptatet;. 100 M.^ FIG. 5. Holotype of Laminoplax dalli lKaa.s. 19571. Girdle fragment to show spicules, mostly broken, reduced to stumps only. 192 THE NAUTILUS October 29, 1981 Vol. 95(4) 100 ^m FIG. 6. Holotype o/Laminoplax ilalii iKaas. 1H57I. Scales on the undprs'urface of the qirdle. dicated that more specimens of the species were available to him from Maine and Georges Banks, none were found. Three lots labelled "Lepido- pleurus carinatus Dall" in the collections of the National Museum of Natural History, Washing- ton, D.C. (USNM 10757; USNM 103477; USNM 34448), examined on a loan arranged through the kindness of Dr. Joseph Rosewater, proved to be misidentifications; no specimens so labelled were found in the Museum of Comparative Zoology, Harvard University, Cambridge, Massachussetts (Dr. Kenneth J. Boss, in litf., 22 October 1979). There remains, also, some ques- tion about the depth at which the single specimen of Lamlnoplax iialli was collected. Dall (1927) did not include it in the original description of the species except for the am- biguous statement that "others" were found in 12 fathoms [22 m]; the accompanying museum label gives no indication of depth, either [the figure "1870" on the original label likely refers to the date of the collection, not to the depth]. In general shape, tegmental sculpture, girdle elements, and posterior gills, Ldminiijihix dulU is undoubtedly in the suborder Lepidopleurina. Despite assigning it to Lepidopleurus. Dall (1927:11) regarded the species as "intermediate between Lcjiidnpleurus and Hanlcya." Ap- parently based on this statement and Dull's description, and without examining the ty})e material, Kaas (1957) assigned dalli to the genus Hanleya, instead. However, neither Dall's (1927) nor Kaas' (1957) generic assignment is correct. Present understanding of these two genera [Lepidopleut'us having no insertion plates; Hanleya having insertion plates in the terminal valves but not in the intermediate valves] indicates that dal.li, for the presence of slitless insertion plates in all valves, belongs in the Afossochitonidae, in a new genus, Lamino- plax, here proposed. ACKNOWLEDGMENTS I wish to express my appreciation to Dr. Joseph Rosewater, National Museum of Natural History, Washington, D.C, Dr. Kenneth J. Boss, Museum of Comparative Zoology, Har- vard University, Cambridge, Massachusetts, and Drs. Peter U. Rodda and Barry Roth, California Academy of Sciences, San Francisco, California, who generously helped me in several phases of this work. Credit is also due to Bar- bara Weitbrecht, California Academy of Sciences, for assistance with the drawings. LITERATURE CITED Adams, Henry and G. F. Angas. 1864. Descriptions of new genera and species of Chitonidae from the Australian Seas, in the collection of George French Angas. Proc. Zoo/. Soc. London, pp. 192-194; 1865. Proc. Zool. Soc. London, pi. 11, figs. 16-17. Angas, George French. 1867. A list of species of marine Mollusca found in Port .Jackson Harbour, New South Wales, and on tlie adjacent coasts, with notes on their hahit.s. etc. Pmc. Zool.. Soc. London, pp. 185-233. Ashby, Edwin. 1921. The rediscovery of Ckoriplax( = Mirro- plax) (jrnyi Adams and Angas (Order Polyplacophora) with notes on its true place in natural systems and the description of a new sub-species. Trans. & Proc. Roy. Soc. So. Auslriilia 45:1.36-142, pi. 9. 1925. Monograph on Australian fossil Polypla- cophora (Chitons). Proc. Roy. Soc. Viclorin 37(N.S., 2): 170-205. pis. 18-22. 1929. Taxonomic value of characters in the Order Polyplacophora. Pror. Mnlaeol. Soc. London 18(4):1,59-16.1. .•\shby. Edwin and Bernard (\ Cotton. 1939. New fossil chitons from the Miocene and F^liocene of Victoria. Rec. So. .Au.-ilralmri A/«.s-. 6(3):209-242. pis. 19-21. Vol. 95(4) October 29, 1981 THE NAUTILUS 193 Ashby. Edwin and W. G. Tcirr. 1901. F'ossil Pdlyplacophora from Eocene beds of Muddy Creek. Moriiin^mi (Schnap- per Point) and Moorabool, Victoria, with definitions of nine new species, and notes on others. Trans. Roy. Soc. So. Australia 25:136-144. pi. 4. Bergenhayn. J. R. M. 1955. Die fossilen schwedischen lori- eaten nebst einer vorlaiifigen revision des systems der ganzen klasse Loricata. Lunds Universitets Arsskrift. N.F. Avd. 2, vol. 5, no. 8, Kungl. Fysiografiska SalLskapets Handl. N.F.. 66(8):3-42, 2 tables." Blainville, H. M., Ducrotay de 1816-1830. Vers et Zoo- phytes. In: Dictionnaire des sciences naturelles. Ft. 2. Regiie organise. Paris, (not seen). Dall, William H. 1927. Diagnoses of Undescribed New- Species of Mollusks in the Collection of the United States National Museum. Prop. U.S. Nat. Mus. 70(no. 2668):l-n. Iredale, Tom and A. F. Basset Hull. 1925. A monograph of the Australian Loricates (Phylum Mollusca - Order Lori- cata). Australian Zool.. 4(2):75-lll. pis. 9-12. Reprinted: 1927. Roy. Zool. Soc. New So. Wales, pp. i-xiii, 1-168, frontis. & pis. 1-21, text figs. 1-4. Kaas, Piet. 1957. Notes on Loricata. 5. On some preoccupied names. Basieria 21:83-87. Kjiorre, Heinrich Von. 1925. Die Schale und die Rucken- sinnesorgane von Trachydermon iChiton) ciriereus L. und die ceylonischen Chitimen der Sammlung Plate. (Fauna et Anatomia ceylonica, IH, Nr. 3) .Jena. Zeitschr. Natur- viss.. 61 (n. ser., vol. ,54):469-632. pis. 18-35. figs. 1-17. Koninck, L. G. de. 1883. Faune du Calcaire Carbonifere de la Belgique. Chitonidae. Ann. jV/«.s-. Roy. Hisf. Nal. Bely. 8:198-213, pis. 5()-.53. Leach, William Elford. 1852. Molluscorum Britanniae Synopsis. A synopsis of the Mollusca of Great Britain arranged according to their natural affinities and anatomi- cal structure. L-ondon. 376 pp., 13 pis, Pilsbry, Henry Augustus. 1892-1894. Polyplacophora. In: Manual of Conchology (G. W. Tryon, Jr., ed.). 14:i-xxxiv + 1-350, pis. 1-68: 1.5:1-132, pls."l-10. 1894a. Notices of new chitons, HL The Naittilus 7(12):138-139. Smith, Allyn Goodwin. 1960. Amphineura. In: Treatise on Invertebrate Paleontology (R. C. Moore, ed.). Part I, Mollusca 1, pp. 47-76, figs. 31-45. Thiele, Johannes. 1909-1910. Revision des Systems der Chitonen. Stuttgart. 132 pp., 10 pis. 1929. Handbuch der systematischen Weichtier- kunde. Loricata: l(l):l-22, figs. 1-22. Jena. Van Belle, Richard A. 1975. Sur la classification des Poly- placophora: H. Classification systematique des Lepido- pleurina (Neoloricata) avec la description des Helmintho- chitoninae. nov. subfam. (Lepidopleuridae) et de Meso- chiton nov. gen. (Helminthochitoninae). Inform. Soc. Beige Malacol. 4(6): 133- 145, 3 pis. 1978. Sur la classification des Polyplacophora: Vn. Errata, additions et rectifications. Resume de la classification. Index alphabetique. Inform. Soc. Beige Malacol. 6(3):6.5-82. FRESHWATER SNAILS OF THE SENEGAL RIVER BASIN, WEST AFRICA^ Emile A. Malek and Jean-Paul Chaine Department of Tropical Medicine and International Health Program, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA 70112 The Senegal River is the second largest river in West Africa. Its river system is about 1,800 kilometers long and drains an area of about 290,000 square kilometers. The Senegal River is formed by the union of the Bafing and Bakoye 'This study was carried out for the United States Agency for International Development, the State Department, and 0. M. V. S., Dakar, through a contract with Gannett Fleming Corddry and Carpenter, Harrisburg, Pennsylvania. It is a part of a study on Assessment of Environmental Effects of Proposed Developments in the Senegal River Basin. Our thanks are due to Dr. Max Miller for encouragement. rivers at the town of Bafoulabe, about 1,060 kilometers u{istreani fmni the Atlantic Ocean. These two rivers, along with the Faleme River, supply almost all the flow entering the Senegal River. This study on the freshwater snails of the Senegal River basin was carried out to assess the situation before two dams are built. One dam, an antisalt dam about 80 km upstream of Saint-Louis at the village of Diama, and a high flow regulatory dam at Manantali in Mali. The 194 THE NAUTILUS October 29. 1981 Vol. 95(4) Diama dam wil! create an impoundment of 235 square km and the Manantali dam an impound- ment with a surface area of 477 square liiisl Sliittiiiis Lire Ih'iiil 3 34 130 205 342 170 82 21 5 4 2 1 1 1,00(1 <20 20-29 30-39 40-49 50 + Total 23 2 4 1 38 27 119 119 837 3 16 10 20 2 18 161 1,010 specimens have been common. The depth and ive status of the specimens used in this report ire shown in Table 2. Twenty-seven of the 38 ;tations included in this study were in "Pinna Beds" (Burch 1980) where T. oahuana is one of he commonest bivalves. Although the type specimen of T. mauai is nore elongate than any of the specimens that ve have dredged, we concur with Dr. Kay's con- lusion that it should be considered a synonym ■f T. oahuana. The type of T. mauai was dredged by Thaanum in 4-8 fathoms near Lahaina, Mauai, in 1918. This is shallower than we have dredged with the Janthina VII but we now plan to dredge at this depth in hopes of finding such specimens. The specimens used in this study have been deposited in the Division of Mollusks, U.S. Na- tional Museum of Natural History at the Smith- sonian Institution in Washington, D.C. LITERATURE CITED Burch, B. L. 1980. Action of the Fcn-.shell Beds. Hdivaiimi Shell News. 28(7): 1. Dall, W. H.. Bartsch, P. & Rehder, H. A. 1938. A Manual of the Recent and Fossil Marine Pelecypod Mollusks of the Hawaiian Islands. B. P. Bishop Mus. Bull. 153. Kay, E. A. 1979. Hawaiian Marine Shells. B. BMop Mu- seum Special Piihl. 64. FIGS. 1-4. 1, Tellina oahuana, lype specimen. USNM no. 333059. Height/length ratuj = 71.8. Burch photo Al7J,-5. 2, Tellina mauai, type specimen. USNM no. 33731,7. Height/length ratio = 59.7. Burch photo Al7Jf-8. 3, Tellina oahuana, Burch Station 77080. 22-26 fathoms offWaikiki. Oahu. (interior) HeightJlength ratio = 69.8. Burch photo N2i9-12. 4, Tellina oahuana, Burch station 77080. (interior of speeimen shoum in Fig. 3). Burch photo N2I,9-1J,. 200 THE NAUTILUS October 29, 1981 Vol. 95(4) Freshwater Snails of AtYica and their Medical Importance bv David S. Brown DISCOUNT PRICE TO NAUTILUS SUBSCRIBERS S49.00 (plus postage) Regular price S55.00 (plus postage) For the first time: A comprehensive account of freshwater snails in Africa and neighbouring islands. An exhaustive guide to species of medical and veterinary importance. An invaluable reference work for malacologists, epidemiologists, parasitologists, freshwater biologists and biogeographers. Published by TAYLOR & FRANCIS LTD, LONDON. Distributed in the Americas by AMERICAN MALACOLOGISTS, INC. FLORIDA. The knowledge resulting from intensive study in recent years is brought together lor the first time in this book. Dr. Brown presents a systematic synopsis of nearly 400 species, most of them illustrated, together with chapters on host/parasite relations, snail control, ecology, distribution and biogeography, accompanied by many maps, photographs of shells and drawings. Dr. David S. Brown is a senior scientist on the staff of the Medical Research Council of Great Bntatn and has been based for 20 years at the Bntish Museum (Natural History) working with a team on research into host/parasite relations. Dunng long penods of field- work in Afnca. he has studied the entire gastropod fauna of fresh and brackish waters over large areas of the continent. 450 pp. 230 ^ 152mm i" x 6") 0 850b6 145 5 Cloth 153 Figs. GUIDE TO THE NUDIBRANCHS OF CALIFORNIA INCLUDING MOST SPECIES FOUND FROM ALASKA TO OREGON Bn G\k> K. McDonald ano '/ (lih-il l>\ K I tH kfr Destined to be the "bihle" lor tidcpool .ind stuh.i hiDJiii^ists, the CukIv In IIh- iVudi/jf.UK /)s III ( ,i/i/iif;)M will f(|UiilK st'r\r those resejrchers Irom Al.isk.i ,ind P,n ilii ( .in.id.i to ( )rfKon I he cvIitisivc inlorm.ilion on the s|)f( lali/cd toods ,mBAKKEN ■\d()i)//i I I -' c olor plates (i4 p