THE NAUTILUS THE PILSBRY QUARTERLY DEVOTED TO THE INTERESTS OF CONCHOLOGISTS VOL. 75 JULY, 1961 to APRIL, 1962 EDITORS AND PUBLISHERS HORACE BURRINGTON BAKER Professor Emeritus of Zoology, University of Pennsylvania CHARLES B. WURTZ Consulting Biologists Inc., Bethlehem Pike, Spring House, Pa. R. TUCKER ABBOTT H. A. Pilsbry Chair of Malacology, Academy of Natural Sciences MRS. HORACE B. BAKER Philadelphia, Pennsylvania PONV PRINTING, UPPER DARBY, PA. April, 1962 nautilus iii CONTENTS Names of new genera, species, etc. in italics Acteocina candei distinct from Retusa canaliculata 87 Adventitious dispersal 94, 124 Alabama 32, 63, 97, 104, 106, 123, 124, 145 American Malacological Union 83 Ancylidae, radulae 97, 145 Anomia aculeata, variation and sculpture 131 Arcidens confragosus in Kansas 95 Arkansas 28 Atlantic, eastern 50, 109 western 1, 7, 21, 40, 50, 55, 85, 87, 94, 108, 109, 127, 128, 131, 138, 149 Australorbis albicans, anatomy and shell 156 Beckianum H. B. Baker (genus of Achatinidae or subgenus of Leptinaria 84 Brachidontes recurvus, gonad development and spawning 149 Bulimulus dealbatus jonesi 166 California, inland 84 marines 19 Canada 103 Capulus sericeus Burch & Burch 19 Camaenidae, Puerto Rican 64 Caracolus marginella mayaguezi H. B. Baker 64 Catinella pugilator Hubricht 31, pi. 4, 61 Catinella texana Hubricht 31, pi. 4, 61 Cerion, anatomy 33 Cionella lubrica, aggregations Ill Clausilia, pallial complex 36 Corbicula fluminea from Ohio River 126 Cuba 156 Cymatium caribbaeum, range extension 94 Dates of the Nautilus 39 Directory of conchologists 40 Engina zonata Gray, type species 107 Eupleura caudata, sexual behavior 7 Europse 36, 39 European Malacological Congress 39 82208 iv NAUTILUS Vol. 75 (Index) Fluorescence, enhancement by glycerin 138 Florida, inland 63, 142 marine 94 Gaeotis nigrolineata 121 Gardner, Julia Anna, obituary 122 "Gastrondonta" saludensis to Helicodiscus 105 Georgia 63, 124 Geotaxis in Physa 75 Glyphyalinia junalaskana, anatomy 125 Gonads and spawning 149 Haiti 71 Helicodiscus barri Hubricht 105 Helicodiscus hadenoecus Hubricht 106 Helicodiscus jacksoni Hubricht 106 Helicodiscus multidejis Hubricht 102 Helicodiscus notius & H. n. specus Hubricht 104, 105 Helicodiscus saludensis 105 Helicodiscus shimeki Hubricht 103 Helicodiscus, subgenus Troglodiscus 105 Helisoma anceps carried by bug 124 Holopodopes, infraorder o£ Geophila 116 Illinois 113, 126 Ilyanassa obsoleta, mass movement 85 Indiana 123 Iowa 103 Jamaica 142 Kansas 46, 95 Kentucky 105, 106 Lacinaria, pallial complex 36 Leptinaria, subgenus (?) Beckianum 84 Louisiana 79 Maryland 62, 107 Mexico 31, 84, 142 Michigan 124 Mississippi 63 Missouri 104 Nenia tridens, anatomy 35 Neoplanorbinae, radulae 145 New Guinea 70 April, 1962 nautilus v New Mexico 28 New York 103 North Carolina 62, 124, 126 Notes and news 39, 84, 123 Nucella 109 Obeliscus (Stenogyra) terebraster rarisinister H. B. Baker 117 Oklahoma 46, 104, 124 Oleacinoids, Puerto Rican 142 Oliva rejecta Burch & Burch 165 Oliva spicata & O. venulata 162, 165 Olivella mutica, reproduction 139 Pacific, eastern 19, 162, 165 Papuina ferussaci 67 "Paravitrea" roundyi to Helicodiscus (?) 107 Physa, geotactic behavior 75 "Pilsbryna" tridens to Helicodiscus (?) 107 Pleistocene 43 Polydontes incerta & P. lima asperula 66 Polygyra gracilis Hubricht 26 Polygyra lithica Hubricht 28 Pomacea paludosa in Alabama 123 Practicolella berlandieri campi 29 Proptera capax in Kansas 95 Publications received 41, 86, (3) iii, (4) iii Puerto Rico 33, 64, 116, 142, 156 Pupillidae 33 Radulae of ancylids 97, 145 Retusa canaliculata distinct from Acteocina candei 87 Rhodacmeinae, radulae 97 Rissoellidae 21 Sagdidae 142 Schwengel, Jeanne Sanderson, obituary 36 Sexual behavior, Eupleura and Urosalpinx 7 Smith, Maxwell, death notice and portrait 84, (4) pi. 18 South America 16 South Carolina 63 Spiraxidae 142 Stenotrema calvescens Hubricht 28 Strobilops lonsdalei & S. I. cansasiana Ho &: Leonard 43, 46 vi NAUTILUS Vol. 75 (Index) Strombus canaliculatus 127, 129 Succinea Indiana 60, 123 Succinea solastra Hubricht 30 Succinea urbana Hubricht 32 Tennessee 29, 102, 105, 106 Thyasira sarsi, synonymy 50 Texas 27, 30, 43, 61 Troglodiscus, subgenus of Helicodiscus 105 Urosalpinx cinerea, sexual behavior 7 Valvata windhauseni Parodiz 16 Vasum globulus nuttingi 1 Vertigo teskeyae 62 Virgin Island marines 55, 108 Virginia 104 Viviparus subpurpureus in Oklahoma 124 X-ray diffraction & shell structure in Oliva 162 Xylophaga atlantica 40 INDEX TO AUTHORS Allen, J. Frances 149 Baker, H. Burrington 33, 39, 64, 84, 116, 142 Basch, Paul F 97, 145 Bode, William T. (Shuster &) 1 Branson, Branley A. 124 Briggs, Rev. H. E. J 39 Burch, John Q 40 Burch & Rose L. Burch 19, 165 Deslandes, Newton (Paraense &) 156 Dexter, Ralph W 40, 85 Donohue, Jerry & Kenneth Hardcastle 162 Dundee, Dee Saunders & Patti Watt 79 Editors 36 Eyerdam, Walter Jacob 71 Fechtner, Frederick R 126 Gregg, Wendell 0 84 Hardcastle, Kenneth (Donohue &) 162 Hargis, William J., Jr. & Clyde L. Mackensie, Jr 7 Henrard, J. B 67 April, 1962 nautilus vii Ho, Tong-Yun & A. B. Leonard 43 Hubricht, Leslie 26, 60, 102, 123, 123, 125, 166 Leonard, A. B. (Ho &) 43 Mackensie, Clyde L., Jr. (Hargis &) 7 McClary, Andrew 75 Merrill, Arthur S 94, 1 3 1 Moore, D. R. (Olsson &) 127 Murray, Harold D 95 Ockelmann, K. W 50 Olsson, A. A. & D. R. Moore 127 Orr, Virginia 107 Owen, D. F 1 24 Paine, Robert T 1 39 Paraense, W. Lobato 8c Newton Deslandes 156 Parodiz, J. J. 16 Rehder, Harald A 1 09 Robertson, Robert 2L 128 Roscoe, Ernest J. 1 1 1 Shuster, Carl N., Jr. & William T. Bode 1 Teskey, Margaret C 83 Watt, Patti (Dundee &) 79 Weber, J. A 55 Wells, Harry J. & Mary Jane Wells 87 Wilson, Druid 122 Woodridge, Richard G., Ill 138 THE NAUTILUS Vol. 75 July, 1961 No. 1 OBSERVATIONS ON VASUM GLOBULUS NUTTINGI, WITH COMMENTS ON OTHER CARIBBEAN VASE SHELLS By carl N. SHUSTER, JR., and WILLIAM T. BODE Department of Biological Sciences, University of Delaware^ and El Camino High School, Sacramento, California The information in this article is based upon the observations by Mr. John B. Henderson, Jr. (Nutting, 1919), and from field notes made in connection with the Smithsonian-Bredin Caribbean Expedition, 1958, and by Mr. Bode during two years, 1957-1958, as a Fulbright Fellow at Antigua.^ Information on the distribution, ecology, evolution, and sys- tematics of the genus Vasum in the western Atlantic is of particu- lar interest to the writers of this article. Since at least three species, V. jnuricatum, capitelliim, and V. globulus (Globivasum) nuttingi (Henderson), have overlapping ranges in the Lesser Antilles, spe- cial care should be made to report the exact locality and observa- tions of each find. Habitat notes. Vasum muricatum and V. globulus nuttingi were found within a few miles of each other at Barbuda, but in dis- tinctly different habitats. Vasum muricatum is generally found in or close to turtle grass beds. Vasum muricatum (Born) Anegada: from Pomato Point in shoal water on Turtle Grass flat. Barbuda: south shore (Gavenor's Landing) . 5 specimens from shallow water, 3 to 6 feet depths, on sandy bottom in region of coral heads and nearby shoreward expanse of turtle grass. Ab- bott (1950) noted that "It seems to prefer rather sheltered, shal- low waters, but is sometimes found on relatively exposed reefs." Antigua: Jumby Bay, Long Island. Vasum globulus nuttingi (Henderson) Barbuda: windward side of Spanish Point. Specimens found in shallow water along coral (dead) rock ledges and on patches of 1 University of Delaware Marine Laboratories, Contribution No. 7. 2 For the opportunities afforded him, as an invited member of the expedi- tion, the senior author wishes to express his gratitude to the sponsors of the expedition, Mr. and Mrs. J. Bruce Bredin and to the expedition leader, Dr. Waldo L. Schmitt. I 2 NAUTILUS Vol. 75 (1) sand among the rocks. Roughly 40% of the specimens were within a few inches of Diadema. Several Vasum were only an inch away from the periphery of the Diadema. Depths were 1 to 3 feet. In only one case, a specimen was collected in another habitat: turtle grass on a sand-covered ledge of coral rock, depth 6 inches. Antigua: from areas just inside points of land, in semi-protected waters. As at Barbuda, where an offshore coral reef broke the direct force of the surf, the localities in Antigua were areas with well-circulated seawater but not exposed to direct surf. We found no Nutting's vase well within bays. Localities included are: Car- lisle Bay: in 3 feet of water. Dead Sands: rocky area on the east side, in 5 feet of water. Ding-a-Dong Nook: in 4 to 5 feet of water. Exchange Bay and Smith Island at Mill Reef: in one to 21/2 feet. Freeman's Bay: inside harbor mouth. Galley Bay: in 3 to 6 feet of water. Literally hundreds of Nutting's Vase shells containing hermit crabs were observed on the Galley Bay side of the point separating Galley Bay and Little Galley Bay. Specimens can be collected at Little Galley Bay when the sea is calm. Guana Island: at the part of the island called the Headlands, at 3 to 4 foot depths. Half Moon Bay: inside rocky area on the Mill Reef side of the bay and in 2 to 6 feet of water, along western shore- line, midway between the sand beach and the open sea to the south. Johnson's Island: northwest side, in 4 to 5 foot depths. Rendezvous Bay: in 4 feet of water; this area may be heavily populated, but extremely rough surge makes it difficult to collect; it was the only locality on Antigua where specimens were found directly exposed to the open sea. Windward Bay: in tide pools formed by a small reef of dead coral, at the water's edge to one and a half feet; in 3 to 6 foot depths outside of the tide pools. Natural history of species of Vasum: Little is known about the living animal. Vasum muricatum is known to be predatory upon worms and clams (Abbott, 1954) ; presumably, the other species are also predatory. In its habitat, Vasum globulus nuttingi escapes notice from all but the experienced collector. Nutting (1919) reported from the notes of Mr. Henderson that, "Miss Sykes seemed to be the only collector with eyes properly focussed to detect these turbin- ellas clinging to the rocks, so well concealed are they by their coloration and by the calcareous deposit that further hides them from their enemy (but not Miss Sykes). One of the chief enemies of these rock-living mollusks is a fish of the grouper family that at high tide swims about the reefs examining every inch of their surface for little mollusks that have not hidden themselves very carefully." Miss Esther Bates, in a mimeographed newsletter, July, 1961 NAUTILUS 3 commented upon collecting at Carlisle Bay, Antigua, on 22 April, 1958: "The tide was low and they [natives] led us to a coral reef at the water's edge. They [Nutting's vase] are difficult to see against the rocky background but I came away with a goodly numbei" ..." Vasiim muricatum may be nocturnal, hiding during the bright sunlight hours among a little species of coral and turtle grass; traveling across the bottom, in 2 to 3 feet of water, in the late afternoon. This may also be the case for V. globulus nuttingi. Most specimens appear to be, to the collector swimming about in search of them, at rest among growths on rocks or partially cov- ered with sand. Possibly visual, audible, or pressure stimuli, caused by the swimmer, cause the snails to "freeze." Specimens removed from the water frequently come part way out of their shells and appear to be quite active. Three of the species have been dredged from moderate depths {Abbott, 1950; Rehder and Abbott, 1951) : V. latiriforme (18 to 20 fathoms) , capitellum (10 fathoms), and globulus nuttingi (7 fathoms) . The type locality of globulus nuttingi was designated as 7 fathoms (Abbott, 1950) , whereas the published account of the living animals (Nutting, 1919) reported them on the rocks in shallow water about the reefs at the entrance to Freeman's Bay. There is no doubt that shallow water areas are characteristic habitats; it remains to be proved that moderate depths are also usual or common. If a range in depth of habitat exists, then a seasonal migration pattern, perhaps for feeding or breeding, may be involved. In this respect, the collections by Bode and Shuster were made only in shallow water, during the period from 9 March through 25 June, 1958. A false distribution may be caused by the activities of predators, such as the grouper (Nutting, 1919) , or by hermit crabs. V. globulus nuttingi has been found at depths ranging from the water's edge to, as a rule, not more than 6 or 8 feet of water. In every case, except at Rendezvous Bay, the snails were found in an area protected from the direct waves of the open sea, yet they were always located where there was considerable water circula- tion. As a rule, they were not found in sheltered areas, as at the head of a bay. The most sheltered habitat observed by Mr. Bode was just inside the entrance to Freeman's Bay, where the snails 4 NAUTILUS Vol. 75 (1) were found in shallow water, not exceeding a foot in depth. Their distribution in this particular area, as in several others, was restricted to a zone covered by a moss-like giowth on the rocks. This growth was not collected nor identified, although it can be recognized easily again once a person has seen it. It appears like a coarse moss, 14 inch to I1/2 inches long, ranging in color from a grey to a brown. In some areas the Nutting's vase was found in the shallow water within a short distance of the beach, among rocks and dead coral, with a higher ridge of rock and dead coral between the open sea and their habitat. Often a bank of live coral would be located at the edge of this "protecting" reef and the water depths quickly dropped off to at least 25 or 30 feet. Although examples of V. globulus nuttingi were found in shallow water, they were within a distance generally not exceeding 50 to a 100 feet from deep water. Specimens of Nutting's vase are frequently found partially buried in pockets of coral sand in crevasses of dead coral. When collected out in the open, on the top of rocks, they are always beneath the water's surface. No examples were ever found on living coral, although some, as at Half Moon Bay, were almost completely encrusted with what appeared to be a living coral. This coral had a very light lavender color when first taken from the water. It completely covered and hid the shape of the shell, with the exception of the aperture. Large numbers of immature V. globulus nuttingi have not yet been found. In some areas only adult specimens occuned. In others, only immature examples were found and when one or two snails were found in an area they were most often immature. On the basis of these observations, since in most areas the adult specimens considerably outnumber the immature ones, we believe that either the young stages are to be found in another habitat, perhaps a breeding area, or that the adult populations are main- tained by a low number of surviving immature snails. Mr. Bode has noted that the local populations can be over-fished. This observation suggests that the snails either have a wider range of distribution, as into greater depths, or more probably, there is a low level of population replenishment due to predation and other forms of mortality or to a low reproductive rate. July, 196 1 NAUTILUS ligmcs a lu d, J'a.suin {(.'Aabivaauin) globulus nutliugi (Henderson), lo illnstrate variation in adult shells: a, the "fossilized" shell frim a kitchen midden, b, characteristic shell, c. an elongate specimen, d, the largest shell. Scale block 5 cm. in length. An area that needs considerably more investigation comprises the small islands off the northeast coast of Antigua, and in par- ticular, the windward side of Long Island and Guana Island. Exchange Island, Little Exchange, Hellgate, Pelican Island and Maid Island should also be more closely investigated. In this general area, dead shells have been picked up that appear to be larger and longer than those found on the south side of the island. Among the several dozens of V. globulus nuttingi collected by Mr. Bode, 3 are worthy of special mention: 2 are atypical, one was found in a kitchen midden. These 3 specimens (figs a, c, d) and a more usual one (fig. b) from Barbuda (Shuster!) are de- picted on page 5. An elongate specimen (fig. c) was collected alive at Windward Bay, Antigua, on 9 March, 1958. It was found at a depth of about 3 feet of water in an area consisting of broken, dead coral and coral rock, with small patches of sand. A very large shell was found in the same area. The third shell (fig. a) was found in a kitchen midden, approximately two feet below the surface, in conjunction with potshard and broken conch and nuuex shells. The midden site was at the western end of a "shell beach" on tlie north side of Antigua, between the airjjort and NAUTILUS Vol. ;i) ■n IP I EupU'ura caudaiu (Say) . Fig. 1 , male and female in ropi.la. Fig. 2. two males attempting copulation with one female. July, 1961 NAUTILUS 7 Long Island. This shell was in a bank approximately 7 feet above mean tide and 10 feet back from the water's edge. Two of these specimens were pictured at slightly larger than actual size by Shuster (1959) : the example with tlie elevated spire and the low- spired shell from the midden. References Abbott, R. T. 1950. The genera Xancus and Vasurn in the western Atlantic. Johnsonia, 2 (28) : 20 1-2 18. 1954. American Seashells. D. van Nostrand, Princeton, N. J. Nutting, C. C. 1919. Barbados-Antigua expedition. University of Iowa Studies in Natural History, 8(3) : 199-203. Rehder, H. A. and R. T. Abbott. 1951. Some new and interesting mollusks from the deeper waters of the Gulf of Mexico. Rev. Soc. Malacologica, 8 (2) -.5 3-66. Shuster, C. N. Jr. 1958. Caribbean adventure. Estuarine Bulletin, 5(2):7-12. SEXUAL BEHAVIOR OF THE OYSTER DRILLS: EUPLEURA CAUDATA AND UROSALPINX CINEREA' By WILLIAM J. HARGIS, JR., and CLYDE L. MACKENZIE. JR.2 Virginia Fisheries Laboratoi7 The observations reported herein are part of an extensive study of the biology of Urosalpinx cinerea (Say) , the smooth oyster drill, and Eupleura caudata (Say) , the rough oyster drill, which is in progress at our laboratory. Results of studies of other aspects of the behavior and ecology of these predatory snails will be re- ported as they become available. Little is known of the copulatory behavior of dioecious marine gastropods. Though Stauber (1943) reported a partial pairing of E. caudata, pairing of U. cinerea has never been described. Our studies show that pairing of both species is a complex process involving fairly intricate behavior of both sexes. Copulation o^ Eupleura caudata. According to Stauber's (1943) description of a partial mating of E. caudata the male mounted the right side of the female and formed the anterior part of his foot into a copulatory groove through which the penis was ex- 1 Contributions from the Virginia Fisheries Laboratory, No. 00. This re- search was conducted under contract with the U. S. Fish and Wildlife Service, Bureau of Commercial Fisheries, No. 14-19-008-2372, Study of Oyster Drills in Chesapeake Bay. - Present address. Bureau of Commercial Fisheries Biological Laboratory, Milford, Connecticut. 8 NAUTILUS Vol. 75 (1) tended into her mantle cavity. Even though disturbed repeatedly this pair copulated intermittently for 21 days. Our laboratory observations of pairing of captive E. caudata confirm and enlarge upon those of Stauber. Eighty-one separate pairings were observed but because the average time each couple was together was ex- tensive and coitus occurred intermittently, only two copulations were seen from beginning to end. Prior to coupling, the female usually moved about the aquar- ium walls and finally assumed a stationary position with her siphonal tip upward. Pairing also occurred in horizontal positions on oysters, or on the aquarium bottom, or rarely, on the walls. The mantle cavity was then exposed by allowing the shell to hang down and away from the posterior part of the foot. Though in most cases a male (or males) had already assumed a position upon the shell of the female, several unpaired females also ex- posed their mantle cavities in the same fashion prior to copulating and probably this behavior is normal precopulatory activity. Fol- lowing this the male often moved about on the female's shell for a short time but eventually assumed a stationary position on her right ventral surface slightly posterior to the mantle cavity with his siphonal cavity pointing in the same direction as hers (Fig. 1, p. 6) . The foot of the male extended to the rim of the mantle cavity and a copulatory groove formed in its anterior surface through which the penis was protruded into the mantle cavity and presumably the vagina, though that orifice was always hidden from view by the shell. On termination of copulation, the female often twisted from side to side and opened and closed the cavity opening. Similar twisting behavior has been observed in other gastropods apparently attempting to dislodge predatory snails, Odostomia, from their shells (Allen, 1958) . The male then with- drew and either remained in position or moved about on the shell of the female or to the substrate. E. caudata usually remained in position and copulated inter- mittently for extensive periods, often up to 48 hours. Two pairs copulated continuously for 2 hours 45 minutes ± 15 minutes and 3 hour 39 minutes ± 10 minutes, and a third for 5 hours ± 10 minutes, but all were paired longer. Another pair copulated intermittently for a total of at least 8 hoins 48 minutes over a period of two days, during which the male maintained his posi- July, 1961 NAUTILUS 9 tion on the female. A marked pair copulated 1 1 times in five months. During this period the pair often separated and the female paired with other males. Eupleura caudata showed marked promiscuity. Of 29 marked pairs, 12 females copulated with more than one male and 15 males with more than one female. One male copulated with 6 different females and one female accepted 5 males throughout the season. Although these are observations on drills confined in running- water aquaria and cages, there is little reason to doubt that, depending on density and movement, similar promiscuity occurs in nature. Usually, males were smaller than their consorts (48 males: mean height 18.7 mm., range 14.9-23.5 mm., standard deviation 2.3; 44 females: mean height 22.6 mm., range 17.5-28.9 mm., standard deviation 3.2) . Seasonal periodicity of copulation was determined in outside cage experiments and running-water aquarium observations. Though the frequency of observation was not always constant throughout the year, the number of pairings seen in aquaria per month roughly corresponded to those in more careful cage exper- iments. In 1956 pairings were recorded as follows: March-6, April-14, May-15, June-3, July-9, August-1, September-1, October- 9, November- 1, and December- 1. The first occurred on March 7 (12.9°) and the first peak occurred in late April and early May. A second peak came in July, comparatively few pairings occurred from July through September, but an increase took place in the last part of October. Copulation ceased after December 10 (10.3°C) . The lowest temperature at which pairings were ob- served was 10.3°C, the highest 28.4°C. Also in 1956, 30 females and 30 males, caged in a single large compartment, were examined every two days between 1400 and 1700 hours. Onset of the mating period was not observed because the experiment was established too late in the season. Pairing was first seen in late April at 13.7°C, reached a peak on June 7 at 23.7°C, and ceased on July 7 at 26.1 °C, (Figure 3). A late wave of 28 pairings, about one-third as intense as the spring wave, began at the end of September (21.7°C) and ended November 11 (16.4°C.) Observations made two or three times a week during the winter of 1956-57 revealed no copulatory activity but this was expected because all other 10 NAUTILUS Vol. 75 (1) i < 1 1 1 1 1 1 1 1 1 i lOvAuHro 9 1IH01a t.joo to on :. Clench. William J. 1936. Mem. Soc. Cuba Hist. Nat. /0:335-342, pi. 25. & C. C. Aguayo. 1937. Mem. cit. //:61-76, pi. 7. Cochran, Doris M. 1928. Biol. Soc. Washington 41:53-60. APPARENT GEOTACTIC BEHAVIOR IN PHYSA By ANDREW McCLARY University of Wisconsin-Milwaukee This note describes an experiment in which snails of the genus Pliysa, identified as P. Integra Haldeman^ were tested for geotac- tic behavior in a mud medium. Method. Six populations of P. Integra, collected from the locations given in Table 1, were used in the study. Experiments were conducted between September 25 and Octobei- 8, 1960. Each population was collected early on a given day, and tested in the afternoon or evening of the same day. The medium in which the snails were tested was a silty mud obtained from the banks of the Milwaukee River at Estabrook Park, on the north side of the city of Milwaukee. The populations designated as "2", "4" and "5" in Table 1 were collected in the same area as the mud. The mud was washed in tap water, sieved through a fine mesh screen, and allowed to dry to a tacky consistency. Some oligochaetes of the family Tubificidae were present in the mud after sieving; no other forms of life were obvious. Before testing a given population, tap water was added to a portion of the mud, which was then used in the test as described below. In some cases, the mud utilized had been employed in previous tests, in other cases, fresh mud was used. Twenty snails were selected at random from the population to be tested, each snail being measured at the time of selec- tion. The average shell length of the animals used was about 7mm. Each snail was placed alone in a 150 ml. glass beaker filled to a level of 4mm. with mud. Although the orientation of the snails was not controlled, most animals appeared to land in an upright postion. Care was taken to place the snails in the 1 The writer wishes to thank Dr. H. van der Schalie, Museum of Zoology, University of Michigan, for kindly identifying the specimens. 76 NAUTILUS Vol. 75 (2) middle of the mud surface. Mud was then added over the snail in each beaker to form a mud column totaling 50mm. in height. The mud column was typically of a consistency such that after a half hour approximately 5mm. of water had collected above its surafce. At the start of a test, each snail was therefore immersed in a mud medium at an approximate distance of 4mm. from the beaker floor, 25mm. from the beaker wall, and 45mm. from the mud surface. The 20 beakers were then placed on a table 4 feet below a 100 watt lamp. Room temperature during the tests ranged from 19-22°C. Beakers were inspected at 5 minute intervals, mud surface, beaker wall, and beaker floor being watched for the appearance of snails. As the mud medium was homogeneous in texture, snails appearing could readily be identified. Each beaker was observed for a period of two hours. If a snail had not appeared by the end of this period, its position in the mud was ascertained by probing. Results. Of the total of 120 snails used in the experiment, 61 surfaced on the mud. Surfacing usually occurred at a point roughly between the center of the beaker and the beaker wall so that, assuming travel in a straight line, the 61 snails moved towards the surface along a path that was at an average angle of 70° from the horizontal. The average time lapse between start of a run and surface appearance was 42 minutes. Eight of the 120 snails were recorded as appearing at beaker walls at points ranging from half way up the beaker wall to just below the mud surface. Again assuming travel along a straight line, snails moving towards a beaker wall did so along a path that was at an average angle of 50° from the horizontal. Average time lapse between start of a run and appearance at a beaker wall was 6.^ minutes. Fifty-one of the 102 test snails did not appear at either the surface or the wall of a beaker. Probing indicated that 15 of these had moved up through the mud medium, having traveled from I/3 to 14 the distance to the sur- face. The remaining 36 snails were found to be in approximately the location where they had been placed at the start of the two-hour period. Snail size did not appear to be a significant factor in the behavior shown. The consistency of the mud medium differed slightly between tests, and this may have been a partial cause October, 1961 NAUTILUS 77 of the behavior variations found between populations. Possibly also more exact tests would reveal actual behavior differences between snails of different populations. A summary of the results is given in Table 1. Table 1 Behavior < 3f Physa in a Mud Medium Date Tested No. of Snails Recovered in Each Four Locations of Population Number Mud Part Way Surface to Surface Beaker Wall Original Location Total 1 9-25-60 8 2 0 10 20 2 9-30-60 Hi 3 1 2 20 3 10-2-60 11 2 1 6 20 U 10-7-60 12 2 2 I 20 ? 10-8-60 9 1 2 8 20 6 10-8-60 7 ? 2 6 20 Total 61 15 8 36 120 Collection sites of popiilations were as follows. 1: Aquarluw in Botany Department at University of Wisconsin — Milwaukee. 2, h, $: Milwaukee River bank at Estabrook Park, Milwaukee County. 3: Stone fountain at Whltnall Park, Milwaukee Coonty. 6? Stream at Kletzsch Park, Milwaukee County. Discussion. Possibly vertical gradients involving physical- chemical properties exist in a mud medium and serve to guide an immersed snail to the surface of the mud. Gradients of this type might conceivably involve differences in temperature, light, oxygen, or in the concentration of various organic or inorganic materials in the mud. An alternate, and perhaps more likely, explanation of the upward movement of the snails in the present experiment is that the mud itself provided no cue as to direction, but that the movement was a true geotactic behavior, or response to gravity. Snails are usually considered to orient to gravity either by statocysts, organs designed to ascertain position in space; or by proprioceptors, sensitive to the differential stresses in muscle which occur in an organism subjected to the pull of gravity (Carthy, 1958). While statocysts are present in snails (Bouvier, 1887; Lacaze- Duthiers, 1872) , these organs have not been clearly shown to 78 NAUTILUS Vol. 75 (2) I'unction in gcotaciic behavior, for the experimental work which has been done in this respect is open to criticism, having proved difficult to repeat (Pieron, 1928; Crozier and Navez, 1930). On the other hand, a strong case has been made for the existence of a proprioceptive control of snail geotactic behavior. Experi- ments have shown that snails which normally show negative geotactic movement will change their direction of travel if muscle stress becomes greater on one side of the body than the other. This latter condition can be brought about by attaching a thread to the shell apex and gently twisting the shell out of line with the snail's body. Snails so manipulated turn so that their body lies along the same axis as the shell, and travel in the new direction determined by this axis, even if the new direction is one that is positively geotactic. It has been concluded from experiments of this sort that snails show- ing negative geotactic behavior have oriented themselves so that there is an equal muscle tension on both sides of the body, as would presumably be true when the shell hangs ventrally. A snail traveling in any direction but upward woidd presumably experience unequal muscle tension due to the weight of the shell (Crozier and Navez, op. cit.) . While possibly snails may orient to gravity by this method in air or water, orientation of this kind would seem less likely to occur in a medium such as mud. In a mud medium, there is probably very little tendency for a snail's shell to sink faster than its body and so create muscle tension, forcing the body to orient upward. This is almost certainly true when a snail is at rest in a mud medium, and is probably true to a large extent when a snail is moving through the medium, although this remains to be verified. In any case, the results of the present experiment indicate that a re-examination of the possible role of statocysts in snail orientation seems desirable. The utility of negative geotactic behavior in some species of snails, such as the tree forms, may be that of enabling an ani- mal to regain its normal habitat after accidental dislodgement (Crozier and Navez, op. cit.) . In aquatic pulmonates, negative geotactic behavior may be a mechanism which sends an animal to the surface to gain oxygen (Cheatum, 1934) , although other factors may also be October, 1901 nautilus 79 involved, as many pulmonates appear never to surface (Russell- Hunter, 1953). The negative geotactic behavior (if such it should prove to be) described here may have been a response to oxygen loss, the latter perhaps resulting from sudden immer- sion in the mud medium. Possibly also a medium such as mud will stimulate receptors in all or a part of the snail's body and that negative geotactic movement results from the stimula- tion. This latter possibility is strengthened by the fact that, wliile no quantitative records were kept, snails often ceased their upward movement as soon as they had surfaced on the mud, although they still had no direct access to air, being below^ the surface of the water which was above the mud. References Bouvier, E. L. 1887. Systems nerveux, morphologie generale et classification des gastropodes prosobranches. Ann. Sc. Nat. Zool. (7) iii: 1-570. Carthy, J. D. An introduction to the behavior of invertebrates. New York. 1958. Cheatum, E. P. 1934. Trans. Amer. Microsc. Soc. 55:318-407. Crozier, W. J. and Navez, A.E. 1930. Jour. Gen. Psychol. 5:3-37. Lacaze-Duthiers, H. 1872, Arch. Zool. Exp. Gen. 7:97-166. Pieron, H. 1928. Jour. Genet. Psychol. 55:3-17. Russell-Hunter, W. 1953. Proc. Roy. Soc, Edinburgh. ^^5 (ii) :- 143-165. LOUISIANA LAND SNAILS WITH NEW RECORDS By dee SAUNDERS DUNDEE and PATTI WATTi Louisiana State University in New Orleans Collections made during the past year have revealed three mollusks not previously reported in Louisiana. Gulella bicolor (Hutton) , known previously from this area by Dr. Harold Harry but not reported by him (personal com- munication, 1959), has been taken from 20 localities in and around New Orleans. Nowhere is it abundant; colonies appear to consist of few individuals which are found only after rains or in very damp habitats. A small colony of Praticolella griseola (Pfeiffer) was dis- covered in the yard of the Laclede Steel Corporation on France 1 This paper is an outgrowth of a current investigation supported by a research grant, RG 7194, from the National Institutes of Health, Public Health Service. 80 NAUTILUS Vol. 75 (2) Road in New Orleans. We have found it nowhere else even though extensive searches have been made. At this locality it is living in and around a pile of steel girders. The pile shows signs of having been there undisturbed for some time. It is part of a barge which used to make trips to Texas. Possibly this is how this colony came to be here. It is an interesting find in view of Pilsbry's statement (1940, p. 689) concerning Praticolella dis- tribution: "The herd of eastern Mexico and Texas is separated from that of the southeastern states by the Mississippi River and State of Louisiana, 300 miles more or less." Vaginula sp. (?) first came to our attention while collecting in Mobile, Alabama. There it is found in large localized colonies. Up to that time we had not discovered it in Louisiana (probably because of a dry period), but shortly thereafter we began finding it in New Orleans. To date it is known from 4 localities in the city. Since little is known of the mollusks of Louisiana, we consider it useful at this time to publish a list of the terrestrial mollusks which have been reported. In this list letters following localities indicate the source of the information as follows: (G) = Goodrich, (Ha) = Haas, (HH) = Harry, (H) = Hubricht, (?) = Pilsbry, (T) = Taylor, (V) = Vanatta, (Vi) = Viosca. Localities are parishes unless otherwise noted. Helix (ispefsa (Miiller) — Orleans, East Baton Rouge (HH, P, Vi).2 H. aperta Born— Orleans (HH, Vi).^ Otala vermiculata (Miiller) — Orleans. (P) ^ O. lactea Miiller— Orleans (HH) .2 Polygyra septemvola febigeri (Bland) — Orleans, Vermillion (P) ; Plaquemines (HH). P. auriformis (Bland) — Orleans, Calcasieu (P) . P. leporina (Gould)— DeSoto (P) ; Grant (H) ; Catahoula (V) . P. triodontoides (Bland) — Calcasieu (P) . P. texasiana (Moricand) — DeSoto (P, HH) ; Grant, Rapides, Caddo, Orleans, Calcasieu, Nachitoches, Tensas (HH) .-^ P. dorjeuilliana Lea — Nachitoches, DeSoto, Bienville (P) ; Clai- borne (H) . 2 These were no longer found in 1948 (Harry) and we have found none of them in Orleans Parish. 3 Specimens may be P. triodontoides (Harry, 1951) . Odobci. HXil NAUTILUS 81 Stcnoticnut lahio.stnii (lihmcl) — -Rapides, I'nioii (P). S. sIcnotreiiKi (Plcillcr) — Madison, Rapides (P) . S. nionodoii (illciac (Pilsbry) — DeSoio, Bienville, (Calcasieu (lype loealiiy (P): Evangeline, Allen, Vernon, Rapides (H) . S. iiionodon loiiu f) icrsoni Pilsbry — -Catahoula (V) . Mcsodon tliyroidus (Say) — Morehouse, I'laukiin. Calahoida (\'): Caleasieu, Grant, Ouaehita (H) . M. nijlfitus (S'ly) — Morehouse, Franklin (V) ; (Caleasieu (H, P) ; Lxangeline, Vernon, Grant, LaSalle (H) . Triodopsis vulluosa (Goidd) — C^alcasieu (P) . T. oagini Call — Naehitoches (P) ; Grant, Claiborne (H) . T. carolifiioisis (Lea) — -DeSoto, Caddo (P) . T. jostcri (F. C^. Baker) — Lake Pontchaitraiu (no parish given) /. (ilhohihris (Say) — included in the range given by Pilsbry — no dehnite localities listed (P): Oua( iiiia (H) . T. dn'csta (Gould) —DeSoto (P) . I Idplotrciiui concavum (Say) — LaSalle (H) . Hiilniiiiliis dealbatiis (Say) — DeSoto (P) . liiDiniiti decollata (Linnaeus) — Orleans (Ci, P, Vi) ; East Baton Rouge (HH). I junellaxis gracilis (Button) — Orleans (HH, P) ; East Baton Rouge (HH). I:iigl(indinti rosea (Feussac) — Orleans, Franklin, Iberia, Iber- ville. \V. Carroll (P) : Plaquemines (HH) . J., rosea biillata (Gould) — Orleans, St. Landry, Lake Pontchar- train (no parish given) , Iberia (P); Franklin (P, V) . liuconulus chersinus (Say) — State of Louisiana (P) ; Catahoula (V); Plaquemines (HH) . /:'. cliersi)ius trocJndus (Reinhardt) — Caddo (P) . E. chersinus dentatus (Sterki) — Catahcjula (\'); Rapides (P) . Guppya sterkii (Dall) —Bienville (?) . Retinella indentata (Say) — LaSalle (H); Morehouse, Catahoula (V) ; Plaquemines (HH). ''. indentata paucilirata (Morelet) — State of Louisiana (P) ; C:iaiborne (P, H) ; Morehouse (V). Mesonipliix friabilis (W. G. Binney) — Morehouse (P, V). M. inilgatus H. B. Baker — Calcasieu, Iberia, Morehouse, Franklin (P) ; Vernon, LaSalle (FI); Morehouse, Franklin (\') . Haivaiia rniniscula (Binney) — included in the range given by Pilsbry — no definite localities given (P) ; Plaquemines (HH); .Morehouse, Catahoula (V) . I'entridens demissus (Binney) — Vernon, Grant, LaSalle (H) ■ /'. demissus brittsi (Pilsbry) — DeSoto, Bienville, Calcasieu (P). /'. intertextus (Binney) — Calcasieu, Claiborne. Evangeline, La- Salle (H) ; Bienville (P). 82 NAUTILUS Vol. 75 (2) Zonitoidcs arboreus (Say) — State of Louisiana (P) ; Morehouse, Richland, Ouachita, Franklin, Catahoula (V) : Plaquemines (HH) . Limax fiaviis Linnaeus — Lincoln (T). Limax marginatiis Miiller — Caddo (HH). Deroceras sp. — Plaquemines (HH) . Deroceras Uicvc Miiller — East Baton Rouge. Ciaddo, DeSoto (HH). Angiaspira (iltern/iln (Say) — Catahoula (P, V): Morehouse, Franklin (V). A. alternata crassa Walker — Caddo, Franklin, Morehouse, De- Soto (P) ; Claiborne, Ouachita, Grant, Calcasieu, Evangeline, Vernon (H) . HeUcodiscus singlcyanus (Pilsbiy) — Morehouse (P, \^) ; Oua- chita (V). H. singleyaniis inermis H. B. Baker — Morehouse, Ouachita (P). Pliilomycus carolinianus (Bosc) — Calcasieu, Evangeline, Rich- land, Ouachita (H) . P. carolinianus flexuolaris Rafinescjue — Grant (P) . Fallifera marmorea (Pilsbry) — Vernon, Grant (H) . Oxylonia sallaena (Pteifter) — Orleans, DeSoto (P). Succinca nnicolor Tryon — Orleans (type locality) (P). .S'. grusx'etwri Lea — Rapides (P) . S'. lutcula Gould — Vermillion, Plaquemines (HH) . S. concordialis Gould — Concordia (type locality) (P) . Strobilops tcxasiana (Pilsbry and Ferriss) — Morehouse, Rapides (P. V). S. labyrinthica (Say) — Morehouse, Catahoula (V). S. aenea Pilsbry — State of Louisiana (P) ; Morehouse, Richland, Catahoula, Franklin; form micrompliala: Rapides, Morehouse, DeSoto, Richland, Franklin, Catahoula (P) . Gastrocopta contracta clnneana (Vanatta) — Orleans, Franklin (V) ; Morehouse, (P, V) ; Plaquemines (HH) . G. corticaria (Say) — Rapides (P). G. pentodon Say — Plaquemines (HH) . G. tappaniana (C. B. Adams) — INIorehouse, Franklin (V) . G. rupicola (Say) — included in the range given by Pilsbry — no definite localities given (P) : Plaquemines (HH) . G. pelliicida hnrdaccUa (Pilsbry) —Gulf States (P). Pupoides albilabris (C. B. Adams)— Gulf States (P) . P. modicns Gould — Placpiemines (HH) . Vertigo inilium Gould — Plaquemines (HH) . V. oscariana Sterki — Madison (P) . V. rugosula Sterki — State of Louisiana (P) ; Morehouse (V) . IJcUcina orbiculata (Say) — DeSoto, Jefferson, Orleans (P) . Bradybaena similaris — (Ferussac) — Orleans (Ha, HH, G). October, 1961 nautilus 83 Literature cited Goodrich, C. 1940. Naut. 53 (3) : 105. Haas, F. 1945. Fieldiana. Zoology 31:2, 3-14. Harry, H. VV. 1942. Occ. Papers of La. State Univ. Marine Lab., No. 1. 1948. Naut. 62 {\) : 20-24. 1951. Naut. 64{?,): 96-99. Hubricht, L. 1956. Naut. 69(4) : 124-26. Pilsbry, H. A. 1939-41. Land Mollusca of North America (North of Mexico) Acad. Nat. Sci. Monographs 3, vols. 1 & 2. Taylor, W. E. 1899. Gulf Fauna and Flora Bull., 1 (3):69-73. Vanatta, E. G. 191 1. Proc. Acad. Nat. Sci. Phil.: 525-531. Viosca, P. 1928. Naut 41 (4): 139-40. THE AMERICAN MALACOLOGICAL UNION Twenty-eighth Annual Meeting, June 20-23, 1961 For the third time in its 30 year history, the American Mala- cological Union convened at the U. S. National Museum in VV^ashington, D. C. Attendance broke all records (150) while the four-day program rolled smoothly along thanks to careful plan- ning and the dedicated services of volunteer members of the National City Shell Club. Behind the scenes was Dr. Harald A. Rehder together with his henchmen Drs. Morrison and Rose- water, all veterans of past A.M.U. meetings, therefore anticipating the requirements of their guests well in advance. President Thomas E. Pulley presided over the academic ses- sions; it was due to his vigilance in enforcing time limits that every paper on an unusually full program was heard. An evening garden party at the beautiful home of Mr. and Mrs. A. Lothrop Lutrell in Rockville, Maryland was the high- light of opening day, and on Thursday the annual dinner was held at the Cumberland Country Club where food, service and sumptuous surroundings left nothing to be desired. The Executive Council met on Wednesday evening and at the annual business meeting on the following afternoon it was an- nounced that it had been found necessary to raise the annual dues one dollar per year with joint and life memberships to be advanced accordingly. (This advance will not become effective until 1962.) No site had been selected for the 1962 meeting, but a com- mittee has been appointed to consider the matter and it is ex- 84 NAUTILUS Vol. 75 (2) pected that the time and place will be announced in the 1961 report bulletin. The following slate of officers for the coming year was pre- sented by the nominating committee and elected by unanimous vote of the members present: President, William K. Emerson. Vice-president, Albert R. Mead. 2nd Vice-president, Robert W. Talmadge. Secretary-treasurer, Margaret C. Teskey. Publications Editor, Morris K. Jacobson. Councillors-at-Large, John B. Burch, H. B. Herrington, Edward H. Michelson, Virginia Orr. The field trip on Friday was a 50 mile excursion to Scientists Cliffs on Chesapeake Bay where the clay banks of the Calvert formation yield a seemingly endless series of Miocene fossils. The trek back to the city was the final featine of the 1961 meet- ing, another to be added to the long list of memorable reunions of the AMU. — Margaret C. Teskey NOTES AND NEWS Beckianum — New genus (or subgenus of Leptinaria Beck, 1837?) in Achatinidae (Subulininae) . Type species is Synopeas beckianum (Pfeiffer) H. B. Baker, 1945, Naut. 58:9\; 1947, Naut. 61 (1) : plate 1, from Cordoba, Mexico. As stated by Zilch, 1959, Handb. Palazool. <5(2):351, Synopeas Jousseaume, 1889, is a homonym of Foerster, 1856. As pointed out in 1945:88, this unique species is very distinct from either Opeas (Ferussaciinae) or Lamellaxis and Leptinaria, sensu stricto (Subulininae) but, from its shell sculpture, it may belong near Pelatrinia Pilsbry, 1907 (1):324, which was proposed as a subgenus of Leptinaria. Pelatrinia has a larger, more conoid and imperforate shell, which carries its columellar cord into the aperture. — H. Burrington Baker. Maxwell Smith — Dr. Joshua L. Baily, Jr., writes from Ashe- ville, N. C, that Maxwell died there Sept. 12, and that a biographic sketch will be prepared for a future number. — H.B.B. Southern California slugs, additional locality records. — The following records are here listed because of their importance in establishing knowledge of distribution. Lehrnannia poiricri (Mabille) . Santa Cruz Island, Stanton October, 1961 nautilus 85 Ranch headquarters (introduced) , 23-1-1960. Dr. Carey Stanton! Prol)abIy all records of Limax marginatvs iMiill. from North America, and certainly all California records of same should be referred to this species^. Anadenulus cockerelli (Hemphill). Kern County, soutli of sawmill at head of Tejon Canyon, Tehachapi Mts., altitude about 5,300 feet, 3-V-1958. W. O. Gregg, W. B. Miller! Ariolimax coliimbianiis stromineus Hemphill. Ventura County, Santa Paula Canyon, altitude about 2,700 feet, 29-V-1955. Ed Peterson! Hesperarion niger (J. G. Cooper) . Kern County, west of Poso Creek and about one half mile north of Glenville — Woody road, 8-VI-1945. Under oak log in damp meadow. W. O. Gregg, M. L. Walton! This is the record which Dr. Pilsbry- refers merely to "northern Kern Co." Tulare County, along Arrastre Creek, about 3 miles east of White River, altitude about 2,200 feet, 26-V-1957. W. O. Gregg, W. B. Miller, W. B. Miller Jr.! Hesperarion hemphilli (W. G. Binney) . Santa Cruz Island, Canada del Puerto, 1.3 mile from Prisoners Harbor, 17-1-1960. Found under old log. W. B. M., W. O. G.! Santa Barbara County, along Salsipuedes Creek near Calif. Hwy. 1, about 3.4 miles south of junction with Hwy, 150, 10-III-1951. W. O. G., W. B. M., W. B. M. Jr.! San Luis Obispo County, near tributary of San Luis Obispo Creek at old ranch road .8 mile north of U. S. Hwy. 101, south side Cuesta Pass, Santa Lucia Mts., 13-n-1960. W. O. G., W. B. M.! Binneya notnbilis J. G. Cooper. Santa Barbara Island, El Primero Canyon, 19-IV-1959. W. O. G., W. B. M.! Shells only, but with epidermis remaining on some shells. Very dry at time of collecting. — Wendell O. Gregg. Mass movement of a colony of the mud snail Ilyanassa. — In a survey of the marine life at Cape Ann, Massachusetts, a dense colony of Ilyanassa obsoleta was discovered on a mud flat border- ing a salt marsh about midway up Little River in 1933. Little River is a side channel to the Annisquam Tidal River, a marine inlet which divides the Cape Ann Promontory. The habitat was very soft, black, sticky mud. The colony in question occupied an area about 85 feet wide and extended outward from the edge of the salt marsh for some 80 feet downshore. In 1935 a series of quadrat counts gave a range of 25-61 with an average of 43 snails 1 Quick, H. E., Proc. Mai. Soc. London, vol. 29, pt. 5, pp. 181-189; British Slugs'. Bull. British Museum, Zool., vol. 6, no. 3, p. 197-200. - I'ilsbi7, H. A., Land MoUusca of North .America, vol. 2, pt. 2, p. 724. 86 NAUTILUS Vol. 75 (2) per quarter square meter. Measurements the next year indi- cated the same abundance. In 1956, quadrat counts ranged from 7-36 with an average of 21 snails. Counts made the next two years gave a range of 9-53 and an average of 26 in 1957; a range of 8-64 with an average of 26 in 1958. I observed, however, that a band of snails, usually not far from the marsh, had a density of about 3 snails per square inch. This band of maximum density seemed to shift with fluctuations of tidal levels between spring tides and neap tides. The 5 quadrat levels at which the counts were made and are quoted above, never fell on this narrow band of maximum density. In 1960 this colony was first visited on August 6. The water level at the time of observation did not permit an extensive sample, but abundance seemed to be about the same as in the past 4 years. On September 6, however, a single snail was found in the area formerly occupied by the colony described above. A search disclosed that the entire colony had moved to a new area some 150 feet northeastward, to the entrance of a ditch which cuts back into the marsh. No explan- ation seems apparent for this mass movement. — Ralph W. Dexter, Department of Biology, Kent State University, Kent, Ohio. PUBLICATIONS RECEIVED, 1960 Pages in italics include new taxons Benthem Jutting, W. S. S. van. Non-marine Mollusca of the lime- stone hills in Malaya. Some zoogeographical remarks on the non-marine Mollusca of the Moluccas. Proc. Cent. & Bicent. Congress of Biology, Singapore, 1958: 63-68, 4 figs.; 164-169, 1 fig. Chernin, Eli, Edward H. Michelson & Donald L. Augustine. Daubaylia potomaca, a nematode parasite of Helisoma tri- volvis, transmissible to Australorbis glabratus. J. Parasitology -^^.•599-607 (2 pis.). Michelson, Edward H. Chemoreception in the snail Australorbis glabratus. Amer. J. Tropic. Med. & Hygiene 9:480-487, 3 figs. 1961 Abbott, R. Tucker. The genus Lnmbis in the Indo-Pacific. Indo- Pacific Mollusca 1 (3) '.28 pp., 18 pis. (1 colored) , maps. Abbott, R. Tucker. How to know the American marine shells. Pp. 222, 12 col. pis., many text figs. Signet Key Book, P. O. Box 2310, Grand Central Station, New York 17, N. Y. {Ibi +5«s postage) . THE NAUTILUS Vol. 75 January, 1962 No. 3 THE DISTINCTION BETWEEN ACTEOCINA CANDEI AND RETUSA CANALICULATA Bv HARRY W. WELLS and MARY JANE WELLS Deparimeni of Biological Sciences, Florida State University, Tallahassee Abbott (1954) has suggested that the opisthobranch gastropods Acteocina candei (Orbigny) and Retusa canaliculata (Say) may belong to the same species and may be merely geographic races or subspecies. The recovery of a large number of Acteocina candei from offshore waters in the vicinity of Cape Hatteras has per- mitted us to compare this form with an equally large number of superficially similar specimens of Retusa canaliculata collected in Pamlico Sound. Our observations and conclusions are presented in this report. Our comparisons led to the discovery of certain as- pects of the biology of Retusa canaliculata not previously re- corded, including the presence of a radula and the occurrence of non-pelagic reproduction in this species. Material. More than 300 specimens of Acteocina candei were recovered from the stomachs of seastars (Astropecten articulatus) collected from a sand bottom off Ocracoke Inlet, North Carolina, at a depth of 4 to 7 fathoms (Wells et al 1961) . Most of these were fresh specimens, from the soft parts of which radulae could be recovered. A similar number of specimens of Retusa canalicu- lata were collected from sand flats 2 to 3 inches below mean low tide along the eastern shore of Pamlico Sound 1 mile north of Avon, N. C. These two collecting stations are separated by a distance of less than 30 nautical miles. While one habitat is oceanic, the other is estuarine, with a greater range in tempera- tures, more rapid temperature changes, and reduced salinities. In addition to these specimens from North Carolina, shells of both species from different parts of their ranges have been ex- amined at the U. S. National Museum. Observations. These "forms" differ in several consistent charac- ters: Oxierall shell shape. Variations in the shell shape of Acteo- cina candei and Retusa canaliculata are shown in Figures 8-10 and 1-3, respectively. Specimens from the oceanic collection {A. 87 NAUTILUS Vol. 75 (3) Figs. 1-3. Retusa canaliculata, showing variation in shell shape. Fig. 3. R. canaliculata with extreme development of the spire (protoconch eroded) . Fig. 4. Acteocina candei, protoconch. Fig. 5. R. canaliculata, protoconch. Fig. 6. R. canaliculata, apical view. Fig. 7. A. candei, apical view. Figs. 8-10. A. candei, showing variation in shell shape. (Fig. 10 shows juvenile condition.) (Figures were prepared with aid of a camera lucida.) January, 1962 NAUTILUS 89 Fig. 11. Egg mass of Retusa ca?ialiciilala. Fig. 12- Radiilar teeth of Acleoci)ia candei. Fig. 13. Radiiiar teeth of R. canaliculata. Fig. 14. R. canali- culata, egg membrane containing veliger. Figs. 15-16. Shell of newly hatched R. canaliculata. (Figures were prepared with the aid of a camera lucida.) candei) are generally spindle-shaped, with an elevated spire and a tapered base, so that the shell is widest in the middle (Figs. 8 and 9) . However, juvenile specimens of A. candei may appear more or less truncate (Fig. 10) , because of the lesser development of the spire. The aperture tapers gradually at its apical end. Specimens from the estuarine collection [R. canaliculata) are more cylindrical in shape, usually with lower spire, with a more rounded base, and with nearly parallel sides, so that the shell is shouldered and nearly as wide near its apical end as it is in the middle (Figs. 1 and 2) . However, there is some variation in the elevation of the spire in R. canaliculata, occasionally approaching (as in Fig. 3) the development characteristic of A. candei. The existence of individuals with such "intermediate" shell characters has no doubt led to confusion in identification. Specimens of both species that show a broad shallow depression in the middle of the 90 NAUTILUS Vol. 75 (3) last whorl (as in Fig. 2) , producing a sinuous outer lip such as that figured by Marcus (1958, fig. 26) for Acteocina {:=Torna- tina) candei have been examined. A similar depression is shown in the shells of Retusa obtusa figured by Lemche (1948, figs. 43- 53) , but in that species also this character is variable and not always present. Because of its occurrence in several similar species and the variability of its expression, such a shallow depression cannot be used as a reliable character for the separation of species. Protoconch. Whereas in A. candei the protoconch is obvious and projecting, in R. canaliculata only a small portion is visible as a small protuberance, and this is often eroded. The hetero- strophic protoconch of A. candei is composed of about one and one-half whorls (Fig. 4) set at an angle of 80° from the axis of the adult shell. It is about i/4 submerged in the first adult whorl (Fig. 7) . In contrast, the heterostrophic protoconch of R. canali- culata contains only about 3/^ of a whorl (Fig. 5) set at an angle of 80° from the adult shell axis. It is about % hidden by the first adult whorl (Fig. 6) . This difference in protoconchs would indi- cate that the planktonic stage is of moderate length in the larva of A. candei, while the planktonic stage is suppressed in the larva of R. canaliculata. Radular teeth. Using the technique described by Turner (1960) , the radulae were mounted for examination. The radular teeth of a specimen of A. candei 2.5 mm. in length are shown in Figure 12. The median tooth is 18 microns wide, 10 microns high, and bears 4 or 5 forward projecting denticles on each of two arches. The lateral tooth, with, an overall length of 45 microns, has a base 33 microns long and a moderately curved cusp 30 microns long; it bears 5 to 7 sharp denticles on an expansion at the angle formed at the base of the cusp. By the same technique, a radula was discovered in R. canaliculata, the teeth of which are shown in Figure 13. For a specimen 3 mm. in length, the median tooth is 30 microns wide, 19 microns high, and is comprised of two arches, each bearing ten or eleven denticles. The lateral tooth is approximately 65 microns long, with a base 46 microns long and a strongly curved cusp 41 microns long that bears 16 to 20 small denticles on a curved ridge. For each species, the radulae of at least 10 specimens were examined. The shape of the teeth and the distribution and relative size of the denticles clearly dis- January, 1962 nautilus 91 tinguish the radulae of the two species. Because of the minute size of the radulae in these species, ade- quate radular preparations are difficult. Evidently, the radulae of both species escaped detection by early workers. Pilsbry (1893) treated both species as having no radula; however, later workers recognized the presence of a radula in Acteocina (Thiele 1931; Marcus 1958, as Tornatina) . Thiele (1925) could find no radula in Retusa canaliculata, and many workers (Marcus 1958, Zilch 1959, and others) have utilized the absence of a radula to charac- teiize the Retusidae, and to place R. canaliculata in this family. The possession of a radula is used for the placement of Acteocina candei in the Scaphandridae. Since R. obtusa (Montagu) is the type species of Retusa, the discovery of a radula in canaliculata makes a re-examination of R. obtusa for the presence of a radula necessary' in order to clarify the position of canaliculata in opisthobranch classification. Until the presence or absence of a radula in R. obtusa is ascertained, we prefer to retain canaliculata in the genus Retusa. Although the possession of a slightly modified shell may reflect environmental differences between two habitats occupied by the same species, the differences considered above can scarcely be attributed to the environment. On the basis of this comparison, these forms should be regarded as biologically distinct species. This group of differentiating characters, particularly the differ- ences in protoconchs and radular teeth, provide unquestionable grounds for the recognition of two species. Acteocina candei occurs from North Carolina south to Argen- tina (Carcelles & Parodiz 1938), principally in offshore or oceanic habitats. In contrast, Retusa canaliculata occurs from Cape Cod to the West Indies, primarily in estuarine habitats. As Parker (1959) noted for the Texas coast, R. canaliculata is a character- istic inhabitant of enclosed bays of variable, low to intermediate salinities. Reproduction in Retusa canaliculata. Egg masses produced by Retusa canaliculata (Fig. 11) were collected on sand flats in Pam- lico Sound, where they were found to be relatively common from May to October. The egg masses of this species bear a resem- blance to one figured by Thorson (1946, fig. 151) as that of Philine scabra. They are composed of a spherical jelly mass about 92 NAUTILUS Vol. 75 (3) 2.0 to 2:5 mm in diameter, attached by a strand about 5 mm long to stems and blades of marine grasses, worm tubes, shell frag- ments, and other objects. Each mass contained a number of large eggs, each within its own egg membrane (Fig. 14) . The envelop- ing egg membranes are ovoid and 0.30 to 0.35 mm in length. Although eggs were usually found only in the enlarged spherical part of the mass, in some cases they were also contained in the attachment strand, as figured. A number of egg masses were re- moved to the laboratory for observation. Development progressed within the egg capsule, through a shelled veliger stage, to a min- iature crawling juvenile. These young snails were observed crawl- ing within their individual egg capsules, from which they event- ually emerged to crawl about the aquarium. These observations constitute the first record of non-pelagic development in Retusa canaliculata. The retention of the veliger stage within the egg capsule un- doubtedly serves to maintain this species in estuarine areas wdiere the net flow of water seaward could carry planktonic larvae away from an otherwise favorable environment. The evolution of such a mechanism would have considerable survival value for the larvae of species that inhabit estuaries. Indeed, non-pelagic development insures a more stable population size (Thorson, 1950) . Such a non-pelagic development has been demonstrated for some species of echinoderms, polychaete annelids, prosobranch gatropods, and pelecypods (Thorson, 1950) . Generally, tecti- branchs have been considered to produce planktonic larvae. Lemche (1948) indicated that studies of the apical whorls of tectibranch gastropods may give reliable evidence about their larval development, and Thorson (1950) successfully applied similar correlations of apical shell form to the development of prosobranch gastropods. According to Lemche's standards, the blunt, relatively coarse protuberance formed by the protoconch of Retusa canaliculata fits the general protoconch morphology that is correlated with a reduced or suppressed planktonic devel- opment. Significantly, Lemche found the protoconch of Retusa obtusa to be wanting, and suggested that it probably exhibits a non-pelagic development. In his svnvey of Danish planktonic larvae, Thorson (1946) had not found larvae that he could assign to R. obtusa, although adults of that species had been known January, 1962 nautilus 93 from the area studied. Evidently, R. obtusa shares with R. canali- culdta a non-pelagic type of reproduction. The relatively large size of the eggs and the prolonged repro- ductive period of R. canaliculata are features that have been correlated with non-pelagic development in other marine inverte- brates (Thorson 1950) . By increasing the chances of successful reproduction, these characters contribute to the effectiveness of non-pelagic development as an effective mechanism for the pro- duction of a new generation without the waste usually associated with plauktonic reproduction. Acknowledgments. These specimens were obtained and studied during the course of research supported by a grant (G-5838) from the National Science Foundation to Dr. I. E. Gray of Duke Uni- versity and aided by the Cape Hatteras National Seashore of the National Park Service. The authors wish to express their appreci- ation to Dr. Harald A. Rehder and Dr. J. P. E. Morrison of the Division of Mollusks, United States National Museum, for making available specimens and literature. References Abbott, R. T. 1954. American Seashells. D. Van Nostrand Co., New York. 541 pp. Carcelles, A., and J. J. Parodiz. 1938. Physis, 12: 251-266. Lemche, H. 1948. K. Danske Vidensk. Selsk. Skr. (Biol.) , 5: 1-136. Marcus, E. 1958. Bol. Oceanogi-. S. Paulo, 7 (1-2) (1956) : 31-80. Parker, R. H. 1959. Bull. Amer. Assoc. Petrol. Geol., 43: 2100- 2166. Pilsbry, H. A. 1893. George W. Tryon, Jr., Manual of Conchology; structural and systematic. Order Opisthobranchia, vol. 15: 134- 436. Philadelphia. Ihielc, J. 1925. Gastropoden der Deutschen Tiefsee-Expedition, Teil 2. Wiss. Ergebn. Deutschen Tiefsee-Exped., 17 {2) Opistho- branchia: 257-288, 348-352. Jena. 1 93 1. Handbuch der systematischen Weichtierkunde, vol. /. G. Fischer, Jena. 778 pp. Thorson, G. 1946. Meddel. Komm. Danmarks Fiskeri- og Havun- dersogelser, Scr. Plankton •/(!): 1-523. 1950. Biol. Rev., 25: 1-45. Turner, Ruth. 1960. Nautilus, 75(4): 135-137. Wells, H. W., M. J. Wells, and I. E. Gray. 1961. Biol. Bull., 120 (2) . In press. Zilch, A. 1959. Gastropoda von Wilhelm Wenz; Euthyneura. Handbuch der Palaozoologie, 6(2): 1-200. Berlin. 94 NAUTILUS Vol. 75 (3) RANGE EXTENSION FOR CYMATIUM CARIBBAEUM WITH A NOTE ON ADVENTITIOUS DISPERSAL By ARTHUR S. MERRILL U. S. Department of the Interior, Fish and Wildlife Service Bureau of Commercial Fisheries Biological Laboratory Woods Hole, Massachusetts A specimen of Cymatium caribbaeum CI. Sc T. was recently sent to me by Mr. Richard Spencer of Charleston, South Carolina. He had collected the example alive from a navigation buoy after it was brought in from its station off Port Royal, South Carolina, to the U. S. Coast Guard Base at Charleston for cleaning and servic- ing. Clench and Turner (Monograph of the family Cymatiidae in the western Atlantic. Johnsonia: 3 (36) : 206, 1957.) record the northernmost range for this species as Lake Worth, Florida. The buoy record thus extends the range northward along the Atlantic coast about 350 miles. The specimen is a thin-lipped juvenile, height 31.7 mm., width 16.1 mm. This is the second species of this genus whose range has been considerably extended northward as a result of buoy sam- pling. The first was a juvenile Cymatium labiosum (Wood) which I collected in 1948 from a buoy brought in from off Cape Romain, South Carolina. This record appears in the monograph by Clench and Turner (1957) on page 202. The Cymatiidae are stenothermic and range widely in all tropi- cal waters. A probable long larval stage aids in their wide dispersal according to Clench and Turner. The larvae of the Cymatium species found on the South Carolina buoys probably chanced to be dispersed northward from Florida by way of rapid transport in the Gulf Stream. Caught in the coastal waters below Cape Hatteras, they finally settled on the convenient buoy surfaces. The normal longitudinal distribution of a species with pelagic larvae is controlled for the most part by the temperature ex- tremes that it can tolerate as an adult. The chance dispersal beyond the consistent range of such a species is probably common. When this occurs and when the larvae happen to settle in a favor- able habitat during a season in which the temperatures are also favorable, the organisms may survive and grow until such time as * Wells, W. Harry and \. E. Gray. The seasonal occurrence of Mytilus ediilis on the Carolina coast as a result of transport around Cape Hatteras. Biol. Bull.: 119 {3): 550-559, 1960. January, 1962 nautilus 95 the temperature becomes lethal. The tact that an adult of the genus Cymatium has never been recorded from the bottom in off- shore Carolinian waters suggests that juveniles are winter-killed. Wells and Gray* recently reported on a cold water species, Mytilus ediilis, which commonly spreads beyond its normal south- ern limit at Cape Hatteras. The species is unable to survive sum- mer temperatures in the northern part of the Carolinian sub- province. However, the larvae of the fall spawning colonize this area after the water temperatures fall below lethal values. There is no need to stress the importance of accurate range records for ecological purposes. In order to increase the accuracy of range records, one must distinguish between that part of the range within which a species is able to maintain itself and propa- gate, and that portion, usually at the extremes, where it is unable to complete its life history. It is also important to record whether the specimen was alive or dead when collected; especially near the borders of its geogiaphic or bathymetric range. Knowledge of extreme range is particularly useful to indicate possible modifica- tions in the usual biota of an aiea should long-range environ- mental changes alter, even slightly, in any direction. ARCIDENS CONFRAGOSUS AND PROPTERA CAPAX IN KANSAS By HAROLD D. MURRAY Department of Zoology, The University of Kansas The extended ranges of the two species of mussels herein re- ported are the result of studies of the unionid fauna of Kansas from the years 1956 to 1959. Call (1885, 1886 and 1887) listed numerous species of unionids in Kansas without descriptions or illustrations, and Scammon (1906) described and illustrated the species of fresh-water mussels occuiTing in Kansas. Neither Call nor Scammon reported these two species as occurring in Kansas. A search of the literature indicates that neither has been recorded for Kansas. Catalogue numbers refer to the mollusk collection of the Museum of Natural History, The University of Kansas, Lawrence, Kansas. Arcidens confragosiis (Say) , KUMNH. 11083. This species was not collected by the author but was uncovered, quite by accident, in the museum collection. R. W. Reese obtained a single gravid 96 NAUTILUS Vol. 75 (3) specimen of Arcidens confragosus from the Marais des Cygnes River, 3 miles east of Ottawa, Franklin County, Kansas, on Sep- tember 25, 1949. Unfortunately, only a half shell of this specimen remains in the museum collection. An empty shell of A. con- fragosus was found at a later date at the same locality, but has subsequently been lost. The half shell remaining in our collection measures 60 mm. in length and 42 mm. in height. A. confragosus was taken from a gravel shoal where the water ranged in depth from one to five feet. Subsequent attempts to collect additional examples have been unsuccessful. Because Utterback (1916:103) reported A. confragosus as oc- curring in northern and central Missouri and because the Osage River (Marais des Cygnes River in Kansas) flows through central Missouri, the presence of A. confragosus in Kansas is not surpris- ing. Possibly A. confragosus may occur in isolated areas in eastern Kansas not yet adequately sampled. Proptera capax (Green) , KUMNH. 10486. A gravid specimen oi Proptera capax was recovered by the author on August 27, 1956 from the Neosho River, 7i/2 miles east and 1 mile south of Em- poria, Lyon County, Kansas. Simpson (1914:47) reported the westernmost range of P. capax as the St. Frances River in eastern Arkansas and two almost certainly invalid records from the Elk- horn and Blue Rivers, Nebraska. Inasmuch as the St. Frances River in Arkansas empties into the Mississippi River a short distance from the Arkansas River and inasmuch as the Neosho River is a tributary of the Arkansas River, it is not surprising that P. capax should occur in the Neosho River in Kansas. Although Utterback (1916:163) reported P. capax in Missouri, his records, as best as can be determined, are from the extreme eastern portion of Missouri. P. capax has not been reported to this date in those streams flowing from Kansas through Missouri to the Mississippi River, which is somewhat surprising considering the appearance of P. capax in the Neosho River. The single example of P. capax thus far known for Kansas is typical in most respects for the species. The nacre is a somewhat darker purple, and the shell is somewhat more elongate than specimens from the Mississippi River. The Kansas specimen measures 155 mm. in length and 101 mm. January, 19(32 nautilus 97 in height. In length, this specimen exceeds the previously re- ported maximum length of P. capax by 12 mm. (Haas, 1941 : 261) . P. capax ^vas recovered from slowly moving water 3i/^ feet deep in a substrate of small rocks and sand having very little silt. Because A. confragosus is a species with unusual morphological features and not likely to be confused with other species, and because Call (1885, 1886 and 1887) and Scammon (1906) did not report this species in Kansas, it seems most likely that A. con- fragosus has made its appearance in Kansas after 1906. It is my opinion that P. capax may have occurred sparsely in Kansas for many years and may possibly have been confused by Call and by Scammon with Lampsilis ovata ventricosa (Barnes) . Literature Cited Call, R. E. 1885. Bull. Washburn College Lab. Nat. Hist., i.-48- 123. 1886. Bull. Washburn College Lab. Nat. Hist., 7.177-183. 1887. Bull. Washburn College Lab. Nat. Hist., 2.11-25. Haas, F. 1941. Zool. Series, Field Mus. Nat. Hist. Chicago, 2^.-259- 270. Scammon, R. E. 1906. Univ. Kansas Sci. Bull., 5.-279-373, pis. 52-86. Simpson, C. T. 1914. A descriptive catalogue of the naiades of pearly fresh-water mussels. Detroit, 1540 pp. Utterback, W. L 1916. Amer. Midi. Nat. 4: (1-10) : 200 pp., 29 pis. RADULAE OF NORTH AMERICAN ANCYLID SNAILS I. SUBFAMILY RHODACMEINAE ^ Bv PAUL F. BASCH Department of Biology, Kansas State Teachers College, Emporia freshwater limpet snails, constituting a distinct subfamily of the family Ancylidae, and limited in distribution to the southeastern United States. Walker (1917) recognized two "sections" or sub- genera of Rhodacmea based partly upon conchological characters, but principally upon features of the radula, to be discussed below. In connection with a continuing study of North American fresh- water limpets, I have reported briefly on the anatomy of one species of Rhodacmea (Basch, 1960) , and more recently have ex- amined the radulae of other species in an attempt to understand better this unusual genus of mollusks. I am indebted to Dr. Henry 1 Supported bv grant G-14125 from the Xaiional Science Fouiidaiion. The genus Rhodacmea consists of about half a dozen species of 98 NAUTILUS Vol. 75 (3) van der Schalie of the University of Michigan Museum of Zoology (UMMZ) for kindly making available to me the material used in this study. The radulae upon which Walker based his systematic con- clusions were prepared for him by Rev. H. M. Gwatkin of Cam- bridge, England. The specimens from which those slides were made were collected in the Tennessee and Coosa River drainages in Alabama, presumably by A. A. Hinkley or H. H. Smith, in the first decade of this century. In Walker's 1917 paper, and again the following year (Walker, 1918) , two figures illustrate the radu- lae of Rhodacmea filosa (Conrad) and R. rhodacme Walker. These drawings were the work of Mrs. Lydia M. H. Green. Al- though probably Mr. Walker examined the preparations himself, there is to my knowledge no direct evidence that he did so. I have examined 7 slides of radulae prepared by Rev. Gwatkin, including those from which Mrs. Green made her original illus- trations. The fact that his preparations have remained in ex- cellent condition for over half a century is a tribute to the skill of Rev. Gwatkin, who died in November, 1916. In addition, I have prepared 24 slides of radulae extracted from dried animals found within their shells in the UMMZ collection. The wide open aper- ture of the limpets and the lack of spiral coiling allowed easy re- moval of the dry animals without damage to the shells. After removal, the animals were soaked for several hours in a 0.5% solution of trisodium phosphate to soften the tissues, and the radulae then dissected out. Although large portions of these frail ribbons could be removed intact, I could not obtain an unbroken radula in this manner. The number of transverse rows of teeth per ribbon could therefore not be determined. In some cases, where bits of tissue adhered to the radula, the entire piece of ribbon was immersed briefly in a dilute solution of sodium hypo- chlorite (clorox) to clean it. Such treatment does not harm the teeth if performed judiciously, and is far more convenient than the traditional sodium hydroxide bath. All ribbons were rinsed in 70% ethyl alcohol and mounted in polyvinyl lactophenol, a mounting medium which dries fairly rapidly and does not require previous dehydration and clearing of the specimen. The following specimens were examined, all UMMZ numbers: A. Prepared radulae from the Gwatkin collection January, 1962 nautilus 99 #946, 947, 948 — 7^. rhodacme Walker, Coosa River. •^9A9 — R. gwatkiniana Walker, Coosa River. :jijt950, 951 — R. clatior (Anthony), Tennessee drainage, Flor- ence, Alabama. #976 — R. filosa (Conrad) , Coosa River B, Radulae extracted and mounted from dry specimens #65998 — R. cahawbensis Walker, Little Cahaba River, Bibb County, Alabama. 2 specimens. #69213 — R. filosa, Coosa River, Talladega County, Alabama. 8 specimens. #69221 — R. giuatkiniana, Coosa River, Coosa County, Ala- bama. 3 specimens. #69223 — R. giuatkiniana, Coosa River, Chilton County, Ala- bama. 4 specimens. #69237 — R. rhodacme, Coosa River, St. Clair County, Ala- bama. 7 specimens. All the identifications of species are those of Walker. A sixth species, Rhodacmea hinkleyi (Walker) was unavailable. The specific features utilized in establishing the two subgenera of Rfiodacmea are as follows (Walker, 1917) : "Section Rhodacmea, s.s. Shell elevated. Radula with a uni- cuspid central, which has the base triangularly expanded; laterals with the cusp of the mcsocone extending bvit little beyond the base and not overlapping the base of the central tooth." Included in this section were R. filosa, R. cahawbensis, R. elatior, and R. hinkleyi. "Section Rhodocephala, n. sect. Shell depressed. Radula with a faintly bicuspid central which has the sides of the base straight and not expanded; laterals with the cusp of the mesocone extend- ing far beyond the base and overlapping the base of the central tooth." In this section were placed R. rhodacme and R. gxvat- kiniana. From my study of these species I have come to the conclusion that there is no constant character by which it is possible to dis- tinguish species or species groupings within Rhodacmea. I submit that the characters utilized by Walker are largely artifacts, which are based upon two conditions — the amount of wear on the teeth examined, and variations in techniques of mounting the ribbon for study. In figs. A to C are shown 3 rows of teeth from a single radula of R. cahawbensis. Changes in the conformation of indi- vidual teeth as a consequence of the amount of wear may be easily seen. The central tooth, originally bicuspid, becomes worn down to a single cusp; the length of the mesocone may vary by 30% 100 NAUTILUS Vol. 75 (3) ^^.'f 3 4 5 6 7 8 mi^ij r- ,.' "t Representative teeth from one radula of Rhodacmea cahaxubensis, UMMZ. #65998, prepared and mounted January, 1961, from a dried specimen. A, teeth near the front of ribbon, showing severe wear; B, teeth from an intermediate area, showing some wear; C, unworn teeth from a region near end of radular sac. Only central and 8 of the 11 teeth on one side are shown. Features marked by small letters in C ilhistrate variable characters: a, central tooth bicuspid or unicuspid; b, degree of overlapping between rows; c, amoimt of "shoulder- ing" on medial surface of first tooth; d, configuration of finer denticles on first January, 1962 nautilus 101 within the same ribbon, and the amount to wliich it overlaps the base and the base of the central tooth are both dependent partly upon wear and partly upon the amount of pressure applied to the coverslip in making the slide. Depending upon the manipu- lation of the preparation, teeth may be rotated into various posi- tions, and may be separated from each other to a greater or lesser degree. The specific areas of greatest apparent variation in the sample studied are pointed out on figure C. Previous studies on the reliability of the radula as a taxonomic tool (Howe, 1930; Van Cleave and Richey, 1936) suggest that this structure alone is not a dependable criterion of specific differences within a genus (in those cases, Vivipariis) . In the present genus, although the radula is of the greatest importance in separating Rlwdacmca, sensu lato from other patelliform fresh-water mol- lusks, I feel that no reliance can be placed upon it in making critical taxonomic decisions within the genus. With regard to the elevated versus depressed shell, this may be a character useful for species differentiation, but I do not believe it to be of sufficient importance to separate subgenera, particularly when the radulae are indistinguishable in all species studied. I must conclude that the subgenera (or sections) Rhodacmea, s.s. and Rhodocephala are based largely upon artifact rather than biological differences, and therefore invalid. In a later paper I hope to discuss the relationships of Rhodacmea within the Ancy- lidae, and of the various species to one another. Literature cited Basch, Paul F. 1960. Naut. 73 (3) : 89-95. Howe, Sam W. 1930. Naut. •/-/ (2) : 53-63. Van Cleave, Harley J., and Emily M. Richey. 1936. Trans. Amer. Micros. Soc. 55(2): 223-229. Walker, Bryant. 1917. Naut. 31 (1) : 1-10. 1918. A synopsis of the classification of the fresh-water Mol- lusca of North America, north of Mexico, and a catalogue of the more recently described species, with notes. Misc. Publ. Mus. Zool. Univ. Mich. 6: 1-213. row of teeth; e, lateral distance between teeth, and basal characters; f, pro- nounced notch present or absent on 4th tooth; g, ninnber of teeth per row (10, 11, or 12, with 1 ribbon of 13). All figures drawn with the aid of a camera lucida. 102 NAUTILUS Vol. 75 (3) NEW SPECIES OF HELICODISCUS FROM THE EASTERN UNITED STATES By LESLIE HUBRICHT HELICODISCUS MULTiDENS, new species. Plate 7, D-F; Text fig. 1 Shell discoidal, spire flat or nearly so; whorls 4i/2 to 5; pale greenish-yellow, dull, opaque. Umbilicus wide and shallow, show- ing all the whorls, occupying from 45 to 50% of the diameter of the shell. Whorls well roundfed, slowly increasing, the last slowly descending; sculptured with numeious, fine, spiral threads. Aper- ture lunate, the peristome somewhat thickened within. Within the last quarter whorl there are 3 pairs of teeth on the outer and basal walls. These teeth are radially elongate, raised on a heavy callous ridge, and separated by a rounded sinus. Alternating with these are 3 teeth on the parietal wall. These teeth extend out to about the center of the whorl, are about twice as broad as high, the ends are turned forward, the upper end more so than the lower. Of the 3 sets of teeth the center set is usually more fully developed than the others. As the shell grows, the teeth farthest within are absorbed and a new set added near the aperture. Height, 1.88 mm. Diameter, 4.75 mm. Umbilicus diameter, 2.22 mm. Aperture height, 1.55 mm. 4.5 whorls. Holotype. Distribution: — Tennessee: Putnam Co.: in Jared Hollow Cave, 3 miles northeast of Chestnut Mound (Thomas C. Ban", Jr., coll.) . DeKalb Co.; in Jim Cave, 1.5 miles southeast of Dowell- town, holotype 207798 U.M.M.Z., paratypes 17063, collection of the author; in Avant Cave, 1 mile east of Dowelltown. Helicodiscus multidens Hubricht; A, view of central pair of teeth. B, parietal tooth from above. C, diagram of tooth arrangement. Helicodiscus multidens is most closely related to H. triodus Hubricht. In H. triodus the teeth are smaller, and the sets of 3 teeth are placed at irregular intervals in the last whorl, not crowded near the aperture. H. multidens is a rare snail, found NAUTILUS Map 1. Distribution of Helicodiscus shimeki Hubricht as represented by specimens in the collection of the author and in the collection of the Uni- versity of Michigan. only in caves. Of the nine specimens so far collected only one was found alive. Helicodiscus shimeki, new species. Plate 7, A-C; Map 1. Shell discoidal, pale yellow, somewhat shining, translucent, spire flat or slightly convex. Umbilicus wide, shallow, showing all the whorls, occupying about 50% of the diameter of the shell. Whorls 5 to 6, well rounded, very narrow and slowly increasing; nuclear whorls with faint spiral striae; later whorls with numer- ous spiral threads. Aperture lunate, peristome thin. Within the last whorl there are usually three pairs of small conical teeth; on the outer and basal walls, the earlier teeth are absorbed. Height, 1.7 mm. Diameter, 4.2 mm. Umbilicus diameter, 2.1 mm. Aperture height, 1.7 mm. 5.2 whorls. Holotype. Type locality: loioa: Delaware Co.: Backbone State Park, holo- type 207796 and paratypes 207797 U.M.M.Z., other paratypes 13807, collection of the author. Helicodiscus shimeki is a species of the northern United States and probably southern Canada, although the author has seen no specimens from there. It ranges from Iowa eastward to northern New York. Map no. 1. Helicodiscus shimeki may be readily distinguished from H. parallelus (Say) by its more slender whorls and its broader, shal- lower umbilicus. It resembles H. salmonaceus W. G. Binney in its proportions, but the thread striae are coarser, and the umbilicus is not quite so broad. It stands somewhat intermediate between these two species. It is named in honor of the late Bohumel Shimek of Iowa City, Iowa. 104 NAUTILUS Vol. 75 (3) Map 2. Distribution of Helicodiscus notius Hubrifcht as represented by specimens in the collection of the author. Helicodiscus notius, new species. Plate 9, N-P; Map 2. Shell discoidal, the spire flat or nearly so; whorls 5 to 5i/^; pale yellowish, dull, translucent when young, becoming opaque with age. Umbilicus wide and shallow, showing all the whorls, occupy- ing from 40 to 45% of the diameter of the shell. Whorls well rounded, slowly increasing, sutures well impressed; sculptured with numerous spiral threads. Aperture lunate, peristome thin. Within the last whorl there are usually 2 or 3 pairs of conical teeth, one on the basal wall and one above it on the outer wall. Height, 1.66 mm. Diameter, 3.66 mm. Umbilicus diameter, 1.62 mm. Aperture height, 1.04 mm. 5 whorls. Holotype. Type locality: Alabama: Jackson Co.: side of Keel Mtn., Paint Rock, holotype 207792 and paratypes 207793 U.M.M.Z., other paratypes 17588, collection of the author. Helicodiscus notius is found over most of the southeastern United States, ranging from the Gulf north to Virginia and west to Missouri and Oklahoma. See map no. 2. Helicodiscus notius differs from H. parallelus (Say) in being a little larger due to the additional whorl; in having a broader, shal- lower umbilicus; and in having the thread striae on the embry- I NAUTILLfS 75 (.H) PLATE j^ ^' HoldlNlK's. \-( . Hclirodiscus shhnrhi Huhiidii. HI'. H. innllidrii.s Huhrichl. NAUTILUS 75 (3) PLATE 8 I K ly^« M II()h)l\|)LS. (,-1. flrli((>ilis(iis noliiis spcciis Hiihiitlil. | .<: R. //. UadciuH'ciis Ihihiiilu. L c<: M, //. jucksoiii Hubricht. January, 1962 nautilus 105 onic whorls more strongly developed. It is most closely related to H. eigenmanni Pilsbry, from which it differs in being smaller and in having a larger umbilicus. Helicodi,sc;u.s notius specus, new subspecies. Plate 8, G-1. Differing from the typical form in being without the internal teeth in shells laiger than two and one-half whorls. The last half whorl slowly descends to the aperture, and the peristome is often much thickened. Type locality: Kentucky: Barren Co.: in Burnette Cave, 0.6 mile west of Park City, holotype 207794 and paratypes 207795 U.M.M.Z., other paratypes 17027, collection of the author. Helicodiscus notius specus is known only from the type locality. In this cave, it was feeding on the guano of the cave-cricket, Hadenoecus subterraneus (Scudder) , in company with Carychium stygium Call. Typical H. notius is occasionally found in caves also, but only where leaves have been washed or blown in. It never has become a guano feeder. Helicodiscus saludensis (Morrison) Gastrodonta (Clappiella) saludensis Morrison, 1937, Proc. Biol. Soc. Wash. 50-58, PI. 4, figs. 1-4. Clappiella saludensis (Morrison) , Pilsbry, Land Moll. N. Amer. II, p. 433, fig. 233. I believe that this species should be placed in the genus Helicodiscus. It is so like H. parallelus (Say) in its general ap- pearance that one needs a lens to distinguish it. H. fimbriatus Wetherby has a similar pattern of internal teeth, although they are not as regularly alternating. Troglodiscus, new subgenus. Shell with numerous, fine, revolving, epidermal fringes; but without the revolving ridges of Helicodiscus s.s. There are no internal teeth at any stage of growth. Type species: Helicodiscus barri. Helicodiscus barri, new species. Plate 9, R-T. Shell small, pale gieenish-yellow, subtranslucent, thin, de- pressed; spire low, convex; whorls 4 to 41/2, well rounded, sutures well impressed. Umbilicus moderately large and deep, contained about 3 times in the diameter of the shell. Sculpture of numerous, fine, revolving epidermal fringes. There being from 40 to 50 of these fringes on the last whorl. Aperture lunate, peristome thin. There are no internal teeth at any stage of growth. Height, 1.8 mm. Diameter, 3.9 mm. Umbilicus diameter, 1.4 mm. Aperture height, 1.3 mm. 4.5 whorls. Holotype. Distribution: Tennessee: Dickson Co.: in Columbia Caverns, 2 miles southwest of Van Leer, holotype 207799 and paratypes 106 NAUTILUS Vol. 75 (3) 207800 U.M.M.Z., other paratypes 17446, collection of the author. Davidson Co.: in Bull Run Cave, 2.5 miles northwest of Scottsboro. Helicodiscus barri is known only from the total darkness of caves. It was found feeding on raccoon dung. It is named for its discoverer, Thomas C. Barr, Jr. Helicodiscus hadenoecus, new species. Plate 8, J-K; PI. 9, U. Shell very small, yellowish, opaque, subdiscoidal; whorls 4, well rounded, sutures well impressed. Umbilicus moderately large and deep, contained from 21/2 to 3 times in the diameter of the shell. Embryonic whorl smooth, later whorls, with fine, re- volving, epidermal fringes, which are found on both the upper and lower surfaces and in the umbilicus. There are from 30 to 40 of these fringes on the last whorl. Aperture lunate, peristome sinuous, not thickened. There are no internal teeth at any stage of growth. Height, 1.2 mm. Diameter, 2.7 mm. Umbilicus diameter, 1 mm. Aperture height, 1 mm. 4 whorls. Holotype. Distribution: Kentucky: Barren Co.: in Beckton Cave, 0.5 mile northwest of Beckton. Tennessee: DeKalb Co.: in Avant Cave, 2 miles east of Dowelltown. Van Buren Co.: in McElroy Cave, 1.5 miles northeast of Bone Cave P. O., holotype 207801 and paratypes 207802 U.M.M.Z., other paratypes 17444, collection of the author. White Co.: in Indian Cave, 2.5 miles southeast of Quebeck. Jackson Co.: in Hargis Cave, 1 mile north of Gran- ville (Thomas C. Barr, Jr., coll.) Alabama: Madison Co.: in Aladdin Cave, 7 miles northeast of Maysville. Helicodiscus hadenoecus is known only from the total dark- ness of caves. It feeds on the guano of the cave-cricket, Hade- noecus subterraneus (Scudder) . It is related to Helicodiscus barri, differing in its smaller size. Dead shells from which the epidermis has been removed show no sculpture other than weak growth lines. They show no ridges like those in H. parallelus. Dead shells resemble those of Hawaiia minuscula (Binney) . Helicodiscus punctatellus Morrison. The type locality for this species is in, not near. Whites Cave, near Mammoth Cave. The author found dead shells fairly com- mon in Whites Cave, but no living specimens. The author visited nearly every accessible cave in Mammoth Cave National Park without finding this species in any other cave. It apparently occurred only in Whites Cave and is now extinct. Helicodiscus jacksoni, new species. Plate 8, L-M; PI. 9, Q. Shell very small, depressed, thin; whorls 4 to 414, well rounded, January, 1962 nautilus 107 sutures well impressed, spire low but convex. Umbilicus wide, occupying about 40% of the diameter of the shell. Embryonic whorl smooth, later whorls with irregularly spaced growth wrin- kles, lower surface of last whorl nearly smooth. Aperture lunate, peristome simple. Height, 1.11 mm. Diameter, 2.44 mm. Umbilicus diameter, 0.96 mm. Aperture height, 0.77 mm. 4.5 whorls. Holotype. Type locality: Maryland: Dorchester Co.: subfossil, in shell mound near beach, 0.5 mile west of Elliott, holotype 207803 and paratypes 207804 U.M.M.Z., other paratypes 22476, collection of the author. Helicodiscus jacksoni is most closely related to Helicodiscus singleyanus inermis H, B. Baker, with which it was found. It differs in its distinctly larger umbilicus and in the more prom- inent growth wrinkles on the upper surface of the last whorl. The whorls are a little more slender and not so tightly coiled. The aperture is smaller. Only dead shells were found, and most of these were chalk white. Some were fresh, these were translucent, with a very pale yellow shell. It is named in honor of Ralph W. Jackson, who discovered this interesting shell locality. Paravitrea roundyi Morrison. PiLSBRYNA TRIDENS MorrisOU. These two species seem out of place in the genera to which they have been assigned. Possibly when they are better known, they will prove to belong to the genus Helicodiscus. TYPE OF THE GENUS ENGINA (BUCCINIDAE) By VIRGINIA ORR The type species of the genus Engina Gray, 1839, is Engina zonata Gray, 1839, by subsequent designation (Gray, 1847) . This species has not been correctly identified by authors because it was not figured; the color pattern is uncommon for the species but principally because, in error. Gray described it as II/2 inches long (misprint?) . Mr. S. P. Dance, of the British Museum, recently showed me a lot of two shells, BV. 113, marked Enzina (sic) zonata Gray in Gray's handwriting. They came from Mr. Guilding and the locality was "West Indies". Neither the adult nor the juvenile shell shows white knobs around the base, the common color-form 108 NAUTILUS Vol. 75 (3) Radula of Engina turbinella (Kiener) , ANSP. 195841, Buccoo Reef, Tobago Island, B. W. I. app. 970 X- of the species, but both are easily identified as the common west- ern Atlantic species, Engina turbinella (Kiener, 1836) . The adult shell measures 11.5 mm. in length (approximately 14 inch) and is here designated lectotype of Engina zonata Gray. I figure it (Plate 10, fig. A) with a similarly colored specimen from St. Thomas, Virgin Islands, ANSP 34755 (fig. B) . The lot from which the lectotype is taken is the one referred to by Tomlin (1928) as "a possible type lot" and misidentified as Engina leucozona (Philippi, 1844). My figure A is from the photograph published by Bartsch (1931) . However, I have in- cluded a scale showing in the original photograph but not previ- ously published because it explains why Bartsch did not recognize the species. Bartsch saw only the photograph of the specimen and had no notes on the size of the shell except the scale photographed with it. Reading, "Axis: II/2 inches" in Gray's description he pre- sumed the scale was an inch rule and translated the size to 27 mm. He made no attempt to identify this outsized Engina. Although, from the misspelling of the generic name noted earlier, this lot of Engina zonata evidently was not labeled by Gray in 1839 (he misspelled Enzina in 1842 and 1847), it prob- ably was in his hands when he designated the type of the genus. It is also the only Gray material of that name which has come to light. Except for the discrepancy in size, the specimens agree well with Gray's description. Fortunately, the better-known name for the species, Engina NAUTILUS 75 (3) PLATE 9 ■s Holotypcs. N!'. Ilclicodiscus noliiis Ilubviclit. (). H. jacksoiii Hubrichi. R- 1 , H. harri Hubrichi. U, H. hadrnocrtis Hiibiichl. I'holographs bv John V,. iV.iuh. I'liiversity of Michigan. NAUTILUS 75 (3) PLATE 10 4 i: n :- 'f^y. / . '» 3 4 Suci'lla lupillii.s: Figs. I -L'. spec inuii lioni liaiut- (I'.S.X.M. (at. No. 12{i,'i(j) . Figs. 3-4, original figures in .\Iaiiini. ITSO. pi. 124. ligs. I IPS, 111). (All ligines approximateh natural size.) I'ig. .V. LctlotNpc oi luio/iui zoitdla (.ia\. H\ . Ii;f. liiitisli Miisciiin. West Indies. .Scale in nun. Fig. M. l-:>ioi)in linb'niclla (Kiencr), AN.SP, 'H7."i,"). St. Ihomas, Virgin Islands. January, 1962 nautilus 109 turbinella ( Kiener) precedes E. zonata by 3 years. Therefore, the type species of the genus Engina Gray is Engina zonata Gray, 1839 (non Reeve 1846) = Purpura turbinella Kiener, 1836. References cited Bartsch, Paul. 1931. Proc. U. S. Nat. Mus., 79 (15) : 1-10, pi. 1, fig. 6. Gray, J. E. 1839. Zoology of the Blossom, pp. 112-113. 1847. Proc. Zool. Soc. London, p. 133. Tomlin, J. R. leB. 1928. Nautilus, -/2 (2) : 40. THE STATUS OF NUCELLA ROEDING By HARALD a. REHDER U. S. National Museum, Smithsonian Institution The genus Nucella was instituted by Roding (Musuem Bol- tenianum, 1798, p. 130-131) for the 5 species listed below. Fol- lowing each name I have given what I believe to be the present correct or proper assignment of the species in question: reticulata Cancellaria reticulata (Linnaeus) . moschatellina Species dubia. macina Nomen nudum. lapillus Paralagena smaragdula (Linnaeus) theobroma Nucella lapillus (Linnaeus) . It will be noted that I have been unable to identify one of the species: N. moschatellina. Roding rechristened with this name Gmelin's Buccinum laeve, repeating the latter's reference to Mar- tini's figures in volume 4 of the Conchylien-Cabinet (1780, pi. 124, fig. 1150). Martini's description of this species in the ac- companying text (Conchylien-Cabinet, vol. 4, 1780, pp. 36-37) does not quite agree with the figures, and later authors have been unable satisfactorily to identify the species. Gray (Zoology Beechey's Voyage, 1839, p. 126) placed it in his new genus Bullia and gave as a synonym sqiialida King. However, the finely striated sculpture and grooved interior of the aperture mentioned by Martini speak against this assignment. The same criticism can be leveled against Pfeiffer's (Krit. Register Martini & Chemnitz Konch. — Kat., 1840, p. 33) suggestion that the species may repre- sent the juvenile stage of Buccinum undatum Linnaeus. Clench, in his treatment of the western Atlantic species of Purpura and Thais (Johnsonia, vol. 2, no. 23, 1947), has dis- cussed on pages 85-86 the problem of the type of Nucella, but 110 NAUTILUS Vol. 75 (3) because 1 have come to a conclusion differing from his I am placing my views on record, as I feel that the nomenclature of this common boreal group should be settled. Nucella was first actively revived by Dall in 1909 (Prof. Paper U. S. Geol. Survey, no. 59, 1909, pp. 46-48, 50) as a subgenus of Thais Roding. Clench (I.e.) is coiTect in stating that Dall did not specifically designate a type, although he undoubtedly in- tended to do so in his outline of the classification on page 50, where he cites T. [hais] lapillus after the name Nucella s.s. Later on, in his paper on the members of this group from northwestern America (Proc. U. S. Nat. Mus. 49, no. 2124, 1915, p. 558) he did definitely designate N. lapillus (Linnaeus) as type. As Clench has pointed out, this is an invalid designation since Linnaeus' species was not included by Roding in his genus. Therefore, Suter (Manual of New Zealand Mollusks, 1913, p. 425), Iredale (Trans. Proc. New Zealand Inst. 47, 1915, p. 472), and Grant and Gale (Mem. San Diego Soc. Nat. Hist. 1, 1931, p. 716) were wrong in accepting Dall's type designation. Wenz (Handbuch der Palaozool., vol. 6, Pt. 1, Lief, 6, 1941, p. 1123) credits Dall with citing filosa Gmelin (lapillus L.) as type, while Winkworth (Proc. Malac. Soc. London 26, 1945, p. 141), credits him with giving N. theohroma as the type species. Both these statements are also erroneous, since Dall, on the one hand, merely listed filosa Menke (not filosa Gmelin) as an example ( 1909: 46) , and, on the other hand, as Clench states, makes no mention at all of Roding's theobroma. Clench, however, has overlooked Winkworth's earlier type designation (Journ. of Conch. 19, 1932, p. 229) , where he un- equivocally gave N. theobroma Roding as type, without crediting it to Dall. This is the earliest valid type designation for Nucella that I have been able to discover. The principal problem seems to be the identity of Nucella theohroma which Clench concludes must be considered a species dubia. Roding refers his species to Bucciniim filosum Gmelin (Syst. Naturae, Ed. 13, vol. 1, Pt. 6, p. 3486), and follows the latter author in citing two figures in Martini (Conch.-Cabinet, vol. 3, 1777, p. 433, pi. 121, fig. 1113-1114) as illustrating the species. Clench feels that these figures are unidentifiable, but to me it January, 1962 nautilus 111 seems to be evident on a number of counts that they represent a form of the common Nucella lapillus (Linnaeus) . First of all. Martini himself, in the accompanying text, considers the shell a variety of lapillus, stating that it differs only in the color pattern; the locality he doubtfully gives as East Indies. Secondly, Roding has renamed the same shell again on page 132 of the "Museum Boltenianum" as Nossa ligata, again referring to Buccinum filosum Gmelin, and to the same figures in Martini. Here it is placed immediately next to Nassa rudis Roding, which as Clench points out, is merely a new name for lapillus. Thus it seems cer- tain that Roding regarded Buccinum filosum as being close to lapillus Linnaeus. Finally, an examination of the U.S.N.M. col- lection of Nucella lapillus revealed a specimen, collected in France, that very closely resembles the figure given by Martini. On plate 10 I give a photograph of this specimen together with a reproduction of the figures of Martini. Considering the varia- bility of the species, I am sure that specimens could be found that match the figure of Martini even more closely. Polytropa Swianson, 1840 (Treatise Malacology, pp. 80, 305) is the next available name, and the one that Clench (op. cit.) used instead of Nucella. Swainson included in this genus Purpura lapillus, which Gray in 1847 (Proc. Zool. Soc. London, pt. 15, p. 138) designated as type. Thus Polytropa, it is true, is the first taxon that was fixed unequivocally on lapillus, but is a name that has been little used, and Nucella, as explained above, is clearly available for this group, and is earlier by 42 years. A survey of the literature over the past 15 years, using the Zoological Record as a source, reveals that 18 authors used the name Thais, without subgeneric assignment, for the species lapillus, 4 (all American) , used Polytropa (as a subgenus of Thais) , and 14 authors used Nucella, all but two as a distinct genus, a procedure that Clench (op. cit.) suggested probably should be followed for this group. AGGREGATIONS OF THE TERRESTRIAL PULMONATE CIONELLA LUBRICA By ERNEST J. ROSCOE Chicago Natural History Museum Widely distributed in Europe, Asia, and north Africa, Cionella luhrica (Miiller) is generally spread over the North American 112 NAUTILUS Vol. 75 (3) continent from northern Alaska to northern Mexico (Pilsbry, 1948) . The species is quite ubiquitous within its range. Although there has been little work done on population density, collectors generally report that C. Inbrica is difficult to obtain in t|uantity. AVhenever large aggregations have been noticed, the observation has been thought of sufficient importance to place on record. Such recorded observations are summarized in the accompanying table, to which the following may now be added. On October 27, 1960 Miss Maidi Wiebe, Staff Artist, Geology Department, Chicago Natural History Museum, observed a large aggregation of C. lubrica, probably totaling several hundred in- dividuals, on the sidewalk in front of her apartment in Oak Park, Illinois, at about 7:30 A.M. The pavement was moist from a brief shower the preceding evening, although the adjacent ground was not particularly wet, the moisture having permeated into the soil. Air temperature was about 47° F. No other organ- isms were observed in association with the snails. At 5:00 P.M. Miss Wiebe noticed that about a fourth of the number of snails observed that morning were still present on the pavement. At 7:30 A.M. the following morning the snails had almost vanished. The temperature was somewhat higher, about 54° F., and the pavement was dry. Heavy rains fell on each of the following two days. A few snails were observed on the walk for a period of about 14 days, none being noticed thereafter. The available data are insufficient to warrant drawing final conclusions. Some tentative suggestions do seem in order, and the summation will at least serve to call attention to the need for additional observations and to indicate the type of informa- tion required. Aggregations of C. lubrica have been observed in widely scat- tered localities in North America, from Massachusetts and Penn- sylvania to British Cohnnbia. I have been unable to find refer- ences to any observed aggregations in the Old World. Quick (1954) states that C. lubrica is much more abundant that its close relative C. lubricella Porro in England. The aggregations have occurred from late May or early June to late October. The majority of observations have been made in late summer or fall. Krull and Mapes (1952) have noted that these snails became increasingly numerous after September 1 in January, 1962 nautilus 113 central New York. They ascribed the greater numbers of snails observed in association with rocks at this time to the increased warmth and protection afforded by the stones. 1 he observed aggregations have generally occurred either dur- ing or preceding a storm. This would tend to support Hender- son's (1905) suggestion that they are a response to physical fac- tors. However, Mapes and KruU (1951) found collecting difficult even after a rain. Additional data on response to various environ- mental conditions is given in Krull and Mapes (1952) . That such aggregations are for the purpose of reproduction has been sug- gested (Anon., 1946; Pilsbry, 1948) . Possibly both physical and biological factors are involved, perhaps depending upon the season. A hint of a cyclic phenomenon is contained in Clapp's (1914) statement that "in 25 years collecting in the Sewickley Valley [Pennsylvania] I have found this species decidedly rare." Long- time observations on populations of C. lubrica are necessary. I plan to keep tab on the Oak Park population during succeeding years. Stephens (1918) found large numbers of these snails fastened by their secretions to the walls of a building, all with the apex of the shell directed downwards. This suggests some sort of oriented reaction (oriented behavior is discussed in Allee et al., 1949 and Warden et al., 1940) . Possibly this behavior was a re- sponse to excessive ground moisture, Mapes and Krull (1951) noting that C. lubrica "is quickly activated and stimulated to climb up when submerged." About 100 of the Oak Park snails were kept under my observation for several days in a small petri dish, the bottom of which was covered by moistened newspaper. There was a noticeable tendency for the snails to concentrate in the center of the dish, in fact to form a pile of snails, when the paper was quite moist. As the paper dried out the snails tended to move out and distribute themselves more uniformly over the bottom. No mating activity was noticed during the relatively short observation period. Oriented behavior is discussed in Allee et al. ( 1949) and in Warden et al. (1940) . These aggregations of C. lubrica are in contrast to the difficulty experienced by Mapes and Krull in collecting this snail in central New York for experimental studies. Some of their collecting was 114 NAUTILUS Vol. 75 (3) 1 1 CD o o >■ tc 3 c C CO re <+ <+ 3 re p. 3- « re o p. >< O ^ 'C o •-I a 3- p' ►« E^- Co u- o re 13 j^ B- a 3 3 13 o CD 3 O P P o !-• •o 3 c+ 0\ ^O O ^0 P. Co re O ^ CO ^ O \J1 Ca V3 --4 O ^ tn CO o ?r 1 re p o H- < 13 « N E^ t- <+ re t- re H- a o o 10 H- 1 P Hg- re 3 p K s o p ►1 p- o M re m h-* < 1 ?r 3 O «< re X H- 1 p . H- O" s: o •-" s o o p p c 0 o cr r+ •1 e+ 0^ < c* n O m O t-" !-• re . O H- o re P \o>< cr p. 1 1 <+ 1 r* ^d" vji re p- S 1 ^- 1 1 1 o a- < re p c << re re c+ o 3 p •1 H- M> re o !-• 3 o o VO « 1 ■'O \o p. i-i 3 0\ >— ' 4^ O vn o o •-4 n o ^ 3 re P P- o- ^ H- o- E O 1-^ o. P! re o M C CI. 13 c P- re 3 "t O S P 1 1 -< cr a P H- re 3 P o c*- P 1 1 O i-t, E < Jq 5 1 o I-" P- 1 C P P <6 p- 8 •1 re 3 fr 3 o ^ J-. 0- H- ^ l-<3 o f^ re p. re P fr 3 H- !-• C D- r"- cri m o 3 f-- 1-4 s o O 3- o p. p. >i p •i) re ►» Oq P P- K- o >->> e° m H' cr o 3 o f+ 3 T O H- O p (_.. pq H- »-[f) >-• M) 1-' m p. 3- P. p <-•- t-^ 3 ►i) - e+ cr 13 re H- - '1 re 13- ►1 s: (K) to P. P M) re <» S- 3- 1 -( "^ (-■ 1 o p 1 p P <+ C+ O 1 «<; o 3 1 1 •-< 1 <+ . . s 1 re 1 S 3- <» 3 ►-• 1:1 0\ p re >-3 CO 1 Oq o -1 1 1 >< ►« O C « re P CD B B cr-o S re o H* >a M 1 H- P. re 3 3- ►1 »<+(!) 3 re o P ►1 o P- cr p. C h*' .tr P re ^ H- i( 3 --J <+ re H- 3 o p. C (-•VJl 0 C O P H S 5 E^ o cr s ^-b o ^ 3 re i-b o <+ 3 p re o re P- o w © o P* pore re B I 1— p. •-I <+ 13 S >-• 1 ►1 i-'l 3 *^ cr re re re re H- P u c < re ere" H- O 1 p- p. r> ~ re o p. c«-a- re re 1 H- o < o- p, to 3 r»- 3 r^ re re re H- H re b C re >i to 3 re c+ O- 3 rl- P- — IT re — — o u 3 o re <-+• P" p o > 3 P p r*- *i m re ►1 P O re ",2 S r+ P o p o o 3* 1 f^- o 3 1 1 3 o cr O HlO P re 3 p 1 1 1 1 I 1 p p re •1 14IP fr, 3 d- »-( S re in ,'1 p. < -1 (H- P re p h o o p. |0 |H- p 1 r January, 1962 nautilus 115 done near Cazenovia, the general locality of Henderson's (1905) observations. Mapes and KruU found it necessary to resort to the use of traps consisting of wet gunny sacks spread over the ground in suitable areas in order to obtain sufficient specimens. These traps, examined two or four times weekly, resulted in only 26 specimens per trap even in favorable sites and under favorable conditions. These authors are of the opinion that the requisite factors for large populations of C. lubrica are moist soil, almost constant shade, and a large quantity of suitable vegetation. The materials required for the culture of C. lubrica are inex- pensive, but such cultures do require a considerable amount of attention. Detailed instructions may be found in Mapes and Krull (1951) . There is here an excellent opportunity for some interested amateur with the time at his disposal to make some very worthwhile observations on the biology of this snail. References Allee, W. C. 1931. Animal Aggregations. Univ. Chicago Press, Chicago, 111. Allee, W. C, et al. 1949. Principles of Animal Ecology. W. B. Saunders Co., New York. See especially Chapter 23, pp. 393- 419. Anon., 1946. Naut. 60:72. Binney, Amos. 1851. The Terrestrial Air-breathing Mollusks of the United States and the Adjacent Territories of North Amer- ica, vol. 1. Charles C. Little Sc James Brown, Boston. Edited by A. A. Gould. Binney, W. C, and T. Bland. 1869. Land and Freshwater Shells of North America, Part 1, Pulmonata Geophila. Smith. Misc. Coll., 194. Clapp, Geo. H. 1914. Naut. 28:96. Fromming, Ewald, 1954. Biologic der mitteleuropaischen Land- gastropoden. Duncker & Humblot, Berlin. Gould, A. A. 1870. Report on the Invertebrata of Massachusetts. 2nd ed. Wright 8c Potter, Boston (1st ed., 1841, not seen). Henderson, J. B. 1905. Naut. /c9;109-l 10. Mapes, C. R. 1951. Cornell Veterinarian ^/. -382-432. Mapes, C. R., and W. H. Krull. 1951. Ibid, II. Cornell Veter- inarian ■/;. -433-444. Pilsbry, Henry A. 1948. Land Mollusca of North America (north of Mexico) . Vol. 2, part 2. Phila. Acad. Nat. Sci., Monogr. No. 3. Quick, H. E. 1954. Proc. Malacol. Soc. London 50.-204-214. Stephens, T. C. 1918 Science, n.s. 43:21]. Warden, C. J., et al. 1940. Comparative Psychology, vol. 2, Plants and Invertebrates. Ronald Press & Co., New York. IHi NAUTILUS Vol. 75 (3) PUERTO RICAN HOLOPODOPES By H. BURRINGTON BAKER The name Holopodopes (plural ot holopod-ops) is proposed here lor an infraorder ot the suborder Sigmurethra, to include the achatinoids (Achatinidae and Spiraxidae) , Streptaxidae, rhytidoids (Acavidae proper -{- Caryodinae, Haplotrematidae, Rhytididae and Chlamydephoridae) and orthalicoids (Urocop- tidae and Orthalicidae or Bulimulidae) . In a systematic ar- rangement, they should precede the Aulacopoda (arionoids, limacoids and testacelloids) and the restricted Holopoda (poly- gyroids, oleacinoids and helicoids) . Some of the reasons for the separation of the holopodopes have been outlined in an earlier paper (1955) . The symbols used for Puerto Rican localities were explained recently (1961). Opeas piimilum (Pfeiffer) . Es2 (coconut plantation) . The older name, Helix hannensis Rang, 1831, from West Africa, which may have been this species, now can be dropped as obsolete. The other widely distributed Opeas, O. pyrgula Schmacker & Boettger, which has less arcuate growth striae, probably also occurs in Puerto Rico, although it has not been reported, unless the older, but obsolete name, Stenogyra alabas- trina Shuttleworth, from near San Juan, represented it. The more typical Ferussaciinae, Cecilioides (Geostilbia) aperta (Swainson) -|- gundlaclii (Pfeiffer) and C. (Karolus) consobrinus (Orbigny) , found by van der Schalie, 1948:50, 51, also have been distributed widely by commerce. Lamellaxis (Leptopeas?) micra (Orbigny) and var. rnargari- taceus (Shuttleworth). Es2 (coconuts), Pnl (yams), Wr2 (cof- fee) , Wr3. All my dry shells (more in alcohol) nearer the smoother form, which is not limited to Puerto Rico; the obsolete name, Stenogyra gompharium Shuttleworth, from near San Juan, may have been based on the typical one. Martens, 1877:345, reported the Cuban L. (Leptopeas) pahi- dinoides (Orbigny) from Aguadilla (Ww), but I got neither it nor the ubiquitous L. (Allopeas) gracilis (Hutton) , which may mean they are more limited to cidtivated areas. Lamellaxis (s. s.) rnonodon (C. B. Adams) and var. opalescens (Shuttleworth). Pnl, Pr3, Wr2, Wn; my only dry shell (Wr2) the imperforate form, which also occurs in Jamaica. January, 19G2 nautilus 117 Obeliscus (Stenogyra) terebraster (Lamarck) . Deep in humus, Er3, 5, Prl-4, 6, Wr2, 3, 1800-4000 ft.; typical larger form. O. (S.) TERKBRASTER RARisiNiSTER, new subspecies. Enl, Es3, 4, Jnl (type locality), Pnl; lowland form smaller throughout, not sim- ply with less whorls. The type, Pilsbry, 1906 (I6a) :pl. 32, fig. 31, a sinistral shell (ANSP. 59320 from R. Swift) of this variety. It measures: 14.4 mm. by 28 (4.1 mm.) with lOi/^ whorls. O. (S.) swiftianus (Pfeiffer) . Ps2 (attains length of 10.5 mm., with 8.2 whorls) & Ws (smaller) ; this species has gone around the world. O. (Pseudobalea) hasta (Pfeiffer) . Under leaves on ground and in moss on tree trunks; Er2, Jnl, Pn, Pr3, 6, Wr, 100-3400 ft. Since Balea dominicensis Pfr., 1853, from "I. Haiti," is identi- fiable only from its inclusion by Pfeiffer himself in the synonymy of O. hasta, the slightly older name is clearly obsolete, even if dated from Pilsbry, 1906 (16a) :272. Subulina octona (Bruguiere) . On ground under dead leaves; Ee, En, Es2-4, Jn, Js, Pn, Pr2, 3, Ps, Wn, Wrl, Ws, Ww; 0-3400 ft. The obsolete Stenogyra (Subulina) acicularis Shuttleworth, based on one shell from near Fajardo, seems to be represented in some eastern lots (Ee, Es2) from near the seashore by occasional dwarfed shells (with fewer whorls, but sexually mature) which have more deeply etched, growth striae, that do crenulate the sutures. Leptinaria unilamellata ( Orbigny) . Widely reported by van der Schalie, 1948:56, probably from cultivated places. Very unfortunately, I, 1945:91, adopted Orbigny's prior name before the more widely used L. lamellata (Potiez & Michaud) would have been saved by the 50 year "rule." Recently, Aguayo, 1961:94, added the other, equally ubiquitous, but more terrestrial L? (Beckianum) beckianum (Pfeiffer) , which already was known from both the Virgins and Haiti. Austroselenites (Zophos) alticola H. B. Baker. Deep in leaf humus, Er2-4, and probably Erl and 5 (too young for exact identification) ; certainly above 2500 ft, on El Yunque and proba- bly Luquillo Mts. above 2000. A. (Z.) co77color (Ferussac) . Also terrestrial. En 3, 4, Jn, Pn, Prl, 3, 4, Wr3, and probably Pr 2, 6, Wn, Wr2 (too young) ; cer- tainly on lowlands, and apparently represented by a smaller, darker race up to 4000 ft. in the Cordillera Central, but my material is too scanty for certainty. The widely transported streptaxid, Diaphera (Huttonella) 118 NAUTILUS Vol. 75 (3) bicolor (Hutton) was found by van der Schalie, 1948:68. Dia- phera Albers, 1850, of which Diaphora Albers-Martens, 1860, is a homonymic emendation, is prior to Gulella Pfr., 1856, and D. bicolor is the type (Nevill, 1878) of Huttonella Pfr., also 1856, of which Indoennea Kobelt, 1904, is a subjective synonym. Brachypodelln (s. s.) riisei (Pfeiffer). Lowlands, En, Jn, Pn, Wn, Ws. B. (s. s.) pallida ("Pfeiffer" Philippi) . Lowlands, En, Jn; Ps2 (beattyiy, VVs (approaching beattyi) . B. (Brevipedella) portoncnnn (Pfeiffer) . En, Jn, Pn, \Vn, Wr2, 0-2300 ft. These 3 species of Brachypodella may occur within a few feet of each other on limestone rocks, but B. portoricana, much the poorest climber, was the only one found (Wr2) far from the limestone rim, and B. pallida, the best climber, was the only species collected at the driest station (Ps2) , where it was buried quite deeply under rocks. Besides their difference in habits, these shells from Ps2 do average smaller and commonly their last whorls are less widely solute (some almost adnate) but the "dif- fers" in riblets seem individual variation. Some are about the size of typical beattyi Clench, 1951:251, fig. 3, from Mona Island; one with all 17 whorls measures 10.3 mm. (over all) by 2.1 (not including aperture) . Many more were found intact but even a little shaking rendered them decollate. Pseudopineria viequensis (Pfeiffer) . In holes and under over- hang of cliffs, on or beneath the limestone outcrops of the north- ern rim, commonly in shaded places where Brachypodella was absent; Jnl, 2. Foot whitish; ommatophores translucent, cylin- dric, with black eyes; inferior tentacles small but certainly pres- ent; sole unizonal, with 1 or 2 waves that involve its full width. Macroceramiis rnicrodon (Pfeiffer). Pilsbry, 1903 (25a) : 1 15- 1 16, pi. 24, figs. 71-72 (ANSP. 251 17 & 25115, from R. Swift) ; van der Schalie, 1948:map 62, pi. 7, figs. 2a, 2b. En, Jn; growth threads narrower than their interspaces (much more so on sub- apical whorls) and irregularly spaced on later whorls. The obsolete M. johannis Pfeiffer appears indistinguishable, and Aguadilla falls within the range of the typical subspecies. M. rnicrodon, var. sliultleiuorthi (ALirtens) , 1877:352 (?) , without exact locality. Pilsbry, fig. 74 (ANSP. 2572, from Bland) ; van der Schalie: fig. 2c. Ws: largest 18.7 mm. long with 12 whorls. Ps2: 1 adult 18.8 mm. long (decollate) and 2 immature, one of which approaches loeryi in growth threads. M. rnicrodon loeryi Jacobson, 1955. Ps2 (near type locality) ; January, 1962 nautilus 119 one adult and 1 immature, empty shells; look as i£ started life like var. a, but assumed later whorls ot var. b, which see. Adult 14.1 mm. by 55 (7.7 mm.) with 7 whorls remaining. M. rnicrodun loeryi, var. a. Ps2, 3. Shells about size and form of typical microdon; one (Ps2) measures: 14.1 mm. by 36 (5.0 mm.) with 11.2 whorls; ranging to 17.2 mm. long with 12.6 whorls; without bluish tinge when alive; 1 shell unicolor, without white patches. AI. microdoji loeryi, var. b. (?) M. shuttleworthi Martens, 1891: 132, Penuelas. Under bunch grass, but climbing 4 to 6 ft. during rain; near Tallaboa (Psl). Shell with growth threads, especially on later whorls, broader than their interspaces and quite evenly and closely spaced; and those on subapical whorls less widely spaced than in typical microdon. Predominant color of shell light sky-blue on living examples but now (1960) almost completely faded to whitish (opaque) with narrow, light brownish (trans- lucent) growth (axial) bands, as were empty shells found nearby (one of last unicolor, without whitish patches) ; with almost no trace of basal angulation in many; largest 21.1 by 37 (7.8 mm.), minor diam. 33 (6.9 mm.) with 13.2 whorls; smallest 19.8 mm. long wuth 1 1 whorls remaining. Living animal light slate color, darker near sole and on ommatophores; mantle collar dark brownish gray, Avith minute light spots; sole unizonal, with 1 or 2 locomotor waves across its full width. In 1939, var. b. was considered a subspecies of M. miaodon (Cf. van der Schalie:96) but I hesitated to name it because of the doubt about the true M. shuttleworthi, which Martens later located at the nearby Penuelas. The above presents the old notes, with a few changes; typical loeryi and var. a were included, as now. Microceramus (s. s.) guanicus H. B. Baker. On rocks near ground; only known from type locality (Ps2) and Mona Island (Clench, 1951). Bulimulus (s. s.) guadalupensis (Bruguiere) . On ground and tree trunks up to 5 ft., Ee, Es2 (coconut plantation), Es4, Jnl, Ps4 (garden) , Wwl (garden) . For this widely disseminated pest, van der Schalie, 1948:87, re- turned to B. exilis (Gmelin). B. (s. s.) diaphanus (PfeiflPer) . More terrestrial, Pnl, Pr2, 4, Ps2, 3, Wn, Ws; 0-3100 ft. Shell epidermis rufous (typical) to whitish. This may be a native species, although described originally from St. Thomas. Pilsbry's, 1897 (9b) : 46-47, transference to this species of the Puerto Rican records of the now obsolete B. fraterculus 120 NAUTILUS Vol. 75 (3) ("Fer." Potiez & Michaud, 1838) is accepted; certainly nothing like the original (P. & M.) figures has been found since. The last name was nude in Ferussac, 1821, livr. 11:54, and in Beck, 1837:67, although Beck questioningly (?) referred it to Helix tenuissirna Ferussac, 1832 (-|- Orbigny, 1835?). Drymaeus (Mesembrinus) virgulatus (Ferussac, 1821) and color form (?) liliaceus (Fer., 1832). Arboreal, edges of Psl (30% Uliaceus) and Ps2 (45% liliaceus) ; empty shells seen elsewhere but only near cultivated places. The separation of these two lots into liliaceus (complete ab- sence of brownish color) and virgulatus (with even a few streaks, up to axial and/or spiral bands of variable continuity) seems highly arbitrary. Confessedly, most of the "lilies" have a less elongate (Roding) form and a slightly swollen last whorl, but they include the most elongate^ shell in the series, and typical virgulatus covers almost the entire range of shell form. These may be hybrids (of an introduced with a native form?) but they cast doubt on any specific separation, even if it has continued for 130 years. D. (M.) multilineatus (Say) ; Cf. form osmenti Clench and/or eboreus Grimshawe. Along road to Wn. One shell from living adult resembling in form, texture and coloration those of Pilsbry, 1946(11) :27, figs. 15b, with similar columellar blotch (absent in thicker and chalkier D. virgulatus) and slightly wider, sutural stripe, but lacking all other dark bands except 4 (plus traces) axial streaks near aperture, and showing no signs of characteristic bluish color near apex. Another shell too broken and bleached to be sure of its form, with similar columellar patch and axial streaks, but without sutural stripe. Neither fits the obsolete Drymaeus hjalmarsoni (Pfr.) , from "near Manati" (between Jn and Pn) , which, as Pilsbry (1899) suggested, seems to have been close to his (1946) Leptodrymaeits, and even might be the subsequently named D. dormani (W. G. Binney) . Simpulopsis (Eudioptusf) psidii (Martens, 1877). Not ob- tained. From field notes, the young shells of Platysuccinea from the Cordillera Central, which approach it in height of spire, were confused with this arboreal species, and thus no special search 1 More so than beattyi Clench, 1951: fig. 6, but less so than his type, figs. 4 & 5. Januai7, 1962 nautilus 121 was made tor it west of Utuado (between Wr6 and Pnl) . How- ever, a shell ot the sagdid at the size of S. psidii (5 by 5 mm.) has one less whorl (2 vs. 3) ; being small, mature 5. psidii might be found only near the end of a long rainy period. Pilsbry, 1902 (31) :lxvii, included both Eudioptus Albers-Martens (not a homonym) and Platysiiccinea in the bulimulid Simpulopsis, but no geophile systematist in this century has guessed either to be a "Bulimulus." The type species of Eudioptus, in which Martens placed his "Bulimus" psidii, is Brazilian, but a dweller on guava leaves might be carried by commerce. Gaeotis nigrolineata Shuttleworth. Mainly on leaves of palms, but also on those of Cecropia and other trees, Er3, 4, 5; in axils of palm pinnae, Wr3; from Luquillo Mts. to western end of the Cordillera Central; 2000-3000 ft. Living animal (Er) 3 by li/g inches (76 by 38 mm.) ; yellowish gieen, but variable; dorsum of foot slaty with yellow middorsal stripe (flavolineata) which often becomes double anteriad; and often with frosty, whitish patches (like albopunctulata.}) ; sides and inferior tentacles lighter, but sole often with orange margin on anterior I/3 (flavolineata); ommatophores blue green, but eyes lighter; mantle (over shell) pea green; often with (internal) black streaks visible (nigrolineata). Very flimsy shell "sigaretiform" but thin lower surface of apical whorls present and containing those of animal, so that separation in preserved examples means damage to one or the other (shells still on most of mine) . Lower surface of apical whorls broken away from all 6 shells studied by Pilsbry, 1899 (35):227-231, as follows: ANSP. 4613, one labeled "albopunctu- lata" and one (4614) "nigrolineata" from Humacao (Bland) . ANSP. 26052, type lot of malleata; 2 shells from "near San Juan," from Swift, collected in 1855. ANSP. 4959, one juvenile labeled "flavolineata" by Bland (not by Pilsbry) from "Luquillo." ANSP. 26051, labeled "nigrolineata" from "Pto. Rico" (Swift). G. nigrolineata is the type species of Gaeotis, by subsequent designation of Kobelt, 1880, 111. Conch.:264. Although only pre- liminary dissections have been made as yet, all my material looks like one variable species, but none of it comes from the lowlands (secretive during dry weather?) . On El Yunque, this bulimulid slug was fairly common, but its coloration blends with the leaves. Additional references (See 1961) 1961 (I), Naut. 74:142. 1961 (5), Naut. 75:64. Aguayo, Carlos G. 1961, Caribb. J. Sci. /.•89-106. Jacobson, Morris. 1955, Archiv f. Molluskenk. 84:91-99. 122 NAUTILUS Vol. 75 (3) JULIA ANNA GARDNER 1882-1960 Julia Anna Gardner, known around the world for her work in stratigraphy and molluscan paleontology, died after a long ill- ness on November 15, 1960. She was a geologist with the United States Geological Survey for 32 years. Julia Gardner was born in Chamberlain, South Dakota, on January 26, 1882. Her undergraduate studies were done at Bryn Mawr College where she received the Bachelor of Arts degree in 1905 and the Masters degree in 1907. Miss Gardner entered The Johns Hopkins University in the fall of 1907, the first woman regularly admitted to the Department of Geology. After receiving her doctoral degree in 1911, she continued there as Assistant in Paleontology until 1915. Her studies of the Late Cretaceous Mollusca of Maryland and other smaller groups were published by the Maryland Geological Survey in 1916. In 1915 she began work on the Miocene Alum Bluff Group of Florida under con- tract with the United States Geological Survey. During World War I, the broad and specific humanitarianism which characterized her life impelled her to go to France with the Red Cross in 1917. She saw strenuous service as an Auxiliary Nurse and after the war with the American Friends in the devastated areas of France. Upon her return to the United States in 1920, Miss Gardner joined the Geological Survey and took up again her professional career, which was to become long and distinguished. She was the author of over 40 reports. Pre-eminent among these are: The molluscan fauna of the Alum Bluff group of Florida: LJ. S. Geol. Survey ProL Paper 142, 1926-1947. The Midway group of Texas: Texas LTniv. Bull. 3301, 1933 [1935]. The Mollusca of the Tertiary form;ttions of northeast Mexico: Geol. Soc. America Mem. 11, 1947. Their scientific value was equaled by their usefulness in the field of petroleum geology, and they are standards of reference in the economic investigations of Tertiary strata of both North and South America. Her published works are foundation stones and bench marks in Coastal Plain stratigraphy and paleontology January, 1962 nautilus 123 that insure Julia Gardner a high place with the pioneers in the geology ot the region. Among the societies of which Miss Gardner was a member are Phi Beta Kappa; Sigma Xi; the Geological Society of America, of which she was a fellow and vice president in 1953; the Ameri- can Association of Petroleum Geologists; and the Paleontological Society, which she served as president in 1952. She was a charter member of the American Malacological Union and was widely known and loved by collectors everywhere. She was an official delegate of the United States to the Inter- national Geological Congress in Madrid in 1926, and to the In- ternational Congress in Moscow in 1937. Julia Gardner made a great contribution in her chosen field of geology; an equally great contribution in the field of human rela- tionship may be exemplified by her encouragement of the Japan- ese scientists while on a tour of duty in Japan after World War II. They confirm that her kindness and generosity heartened them to carry on their researches. In her wide circle of friends, few do not have cause to remember some kindness, some encouragement, some tangible assistance, timely, but given unexpectedly. Julia Anna Gardner will live long in the hearts of her friends. — Druid Wilson. NOTES AND NEWS PoMACEA PALUDOSA IN ALABAMA — In 1943, John Richardson II collected Pomacea paludosa (Say) at Gainesville, Florida, and introduced it into ponds on his farm 7 miles north of Jackson- ville, Florida. From here, in 1953, Frank Lyman introduced it into a small pond on the shore of Gantt Lake, 5 miles northeast of Gantt, Covington Co., Alabama. It soon escaped into Gantt Lake, and is now to be found along the shore for a mile in either direction from Lyman's pond. — Leslie Hubricht. S\ic<:iriea Indiana Pilsbry. Succinea Indiana Pilsbry, 1905, Nautilus, 19: 28. Siiccinea vaginocontorta Lee, 1951, Occas. Papers Mus. Zool. Univ. Mich. no. 533, pp. 1-7, PI. 1-2. A careful examination of the anatomy and shell of topotypes 124 NAUTILUS Vol. 75 (3) Succinea indiana showed no character which could be used to distinguish it from S. vaginacontorta. The same twisted vagina is found in S. indiana. S. vaginacontorta Lee must be placed in the synonomy of S. indiana. Additional records for Succinea indiana are as follows: Xorth Carolina: Craven Co.: sandy roadside, 4.4 miles west of New Bern. South Carolina: McCormick Co.: below Clark Hill Dam. Georgia: Richmond Co.: roadside, 1600 Gordon Highway, Au- gusta. Alabama: Montgomery Co.: waste ground, Atlanta High- way and Forest Hills Ave., Montgomery. Dallas Co.: near Ala- bama River, opposite Selma. — Leslie Hubricht.' ViviPARUs suBPURPUREUs IN OKLAHOMA. — A single Specimen, 33.0 mm. in height and 32.0 mm. in greater diameter, of this species was discovered in a small, mud-bottomed, heavily-vege- tated stream at the south boundary of Tom, McCurtain County, Oklahoma on 16 July, 1961. The spire was greatly eroded. Al- though this specimen represents a new record for Oklahoma, it is not a particularly surprising one. The Austroriparian Biotic Province extends into Oklahoma at this point but it is separated from the main body of that ecological division by the Red River. Viviparus subpurpureus (Say) is a fairly common species in ad- jacent Texas and Louisiana but apparently has met some diffi- culty in traversing the river barrier into Oklahoma, as I have collected rather extensively in this part of the state and have not found the species before. — Branley A. Branson, Dept. of Biol- ogy, Kansas State College, Pittsburg. Helisoma anceps transported by a giant water bug. — On 5 May, 1961, I collected a giant water bug, Lethocerus americanus (Leidy), which had been attracted (at night) to a lOO-watt mercury lamp on a lawn at the University of Michigan's Erwin S. George Reserve, Livingston County, Michigan. The bug was carrying on its scutellum a specimen of Helisoma anceps (Menke) . The snail was alive and appeared to be immature, measuring 5 mm. high and 7 mm. long. Giant water bugs of this species and a similar species, Benacus griseus (Say) , frequently come to lights in early spring and later in the summer; evidently 1 Accidentally omitted from Naut. ?'':()(). — H. B. B. I January, 1962 NAUTILUS 125 there is much movement between ponds, presumably associated with mating behavior. Any animal that happened to become attached to a bug would be similarly transported. During 1959- 61, I examined about 500 of these bugs, but this is the only occasion I found an attached snail. But among several hundred hydrophilid beetles similarly attracted to light, I found 3 with immature leeches attached to their elytra. The leeches at first ap- peared dead, but quickly became active when placed in water. In view of frequent speculation as to how totally aquatic animals colonize isolated ponds, these records may be of interest. — D. F. Owen, Museum of Zoology, University of Michigan, Ann Arbor. The anatomy of glyphyalinia junaluskana. — Glyphyalinia junaluskana (Clench & Banks) generally has been treated as a subspecies of G. sculptilis (Bland) . However, a study of the genitalia shows that it is quite distinct. The following descrip- tion of the lower genitalia is based on a specimen collected at Glyphyalinia junaluskana (Clench & Banks). Three views of terminal genitalia, drawn with aid of camera lucida. Scale line = 1 mm. 126 NAUTILUS Vol. 75 (3) 4700 ft., 0.6 mile southeast of Beech Gap, GTaham Co., North Carolina. Penis (fig.) rather short and stout, club-shaped, basal portion nearly white; upper portion pale brownish, globose. Penial retractor short and stout, inserted at apex of penis. Epiphallus parallel to penis, long and stout, as large as the penis; upper end deeply cleft into two equal lobes; lower portion pale brown, becoming darker at upper end. Spermatheca narrowly obovate, not clearly differentiated from the thick duct. Vagina and free oviduct short. It differs from G. sculptilis in being without the penial appen- dix of that species and in having the epiphallus divided into two distinct lobes. It apparently belongs in section Glyphyalinia. s. s rather than in section Glyphognomon H. B. Baker. — Leslie HUBRICHT. CoRBicuLA FLUMiNEA (Miiller) from the Ohio River — On a field trip last August 30, 1960, to the Ohio River just east of Fort Massac and Metropolis in Massac County, Illinois, I col- lected 1 1 recently dead specimens of Corbicula (Corbicula) flu- minea. They were 15-20 feet from the north bank in 6'' of water. The bottom was more gravel than sand with very little mud present. The areas on either side were muddy bottoms and about one foot deep, yet no specimens were found. Corbicula fiinninea, a native of eastern Asia, has not been reported from the northeast or central states as of this writing; therefore, I can mention those collected at Metropolis, Illinois, as new in this part of the country. Sinclair and Ingram (1961, Naut. 7-/:l 14-1 18) reported the species' presence in the Tennessee River in Hardin County, Tennessee. Previously, the species was known only from the south to north western states, i.e., Arizona, California, Idaho, Nevada, Oregon and Washington (op. cit.) . Corbicula flumiyiea seems to be widely distributed over the United States. Records of its further spread are to be expected with additional collecting. Since I am not an expert on foreign sliells, the specimens were submitted to Dr. Fritz Haas of Chicago Natural History Museum for identification. They are now Chicago Natural History Mu- seum No. 103678. Sincere appreciation is extended to Dr. Haas for his assistance. — Frederick R. Fechtner. I THE NAUTILUS Vol. 75 APRIL, 1962 No. 4 A NEGLECTED WEST ATLANTIC STROMB By a. a. OLSSON and D. R. MOORE In 1949, Mr. Leo A. Burry described and figured (Shell Notes, December, 1949) , a most unusual Strombus under the name of S. canaliculntus, reported as having been taken in a fish-trap set at a depth of 175 fathoms off Hopetown, Elbow Key in the Bahamas. The whereabouts of the type is unknown. The figure shows an immature specimen in which the lip is not yet fully formed. Subsequent to the description of the species, the junior author saw 3 additional specimens which Burry had obtained from the same source. Two specimens were half grown and smaller than the holotype, the third was fully matured with a flared and thickened outer lip. This last specimen, a topotype, is in the reference collection of the Marine Laboratory of the University of Miami (Accession no. 30:1839). It measures 242 mm. in length. (Plate 11.) The full-grown shell has a high, broad, conic spire of 8 or more whorls, each edged with a sharp, peripheral keel or carina, the main surface of each spire-whorl smooth, except for the fine lines of growth. There are no axial riblets at any stage. The peripheral keel becomes more strongly emphasized on the shoul- der of the body-whorl and at its termination on the edge of the outer lip it forms into a deep notch. The wall of the shell is quite heavy, interior of aperture with a pink coloration and the surface is covered with the usual, light-brown, peeling perio- stracum. The report that this shell was taken from a fish-trap seems very questionable. There seems to be notliing closely re- lated to S. canaliculatus in the living fauna; S. leidyi Heilprin of the Florida Pliocene is perhaps the nearest, but even in this case, the resemblance is not close. The collection of at least 4 typical specimens of S. canaliculatus in a relatively short time and from the same general area seems to preclude a chance anomaly or a deformed or diseased shell. The absence of axial ribbing on any part of the whorls of the 127 128 NAUTILUS Vol. 75 (4) spire is again emphasized. More material with accurate data as to station and environment is needed and we are calling re- newed attention to this interesting species so that collectors visiting the Bahamas can be on the watch for it. THE STATUS OF STROMBUS CANALICULATUS By ROBERT ROBERTSON Assistant Curator of Mollusks, Academy of Natural Sciences of Philadelphia Olsson & Moore (1962) have claimed that Strombus canalicu- latus Burry (1949) is a distinct, "neglected" species, not closely related to any other living species. They have discounted the idea that the 4 known specimens are abnormal. 5. canaliculatus was originally described on the basis of a sin- gle, sub-adult shell, purportedly from a fish trap in 175 fathoms off Hope Town, Elbow Cay, Great Abaco, Bahama Islands. The trustworthiness of this type locality has bearing on the validity of this species. If, as Olsson has suggested (m litt.), it is a deep water, "outer shelf" species, it could have been overlooked. Unfortunately, Burry gave no information as to how he ob- tained the holotype. According to D. R. Moore {in litt.) , Burry obtained it from a man named Ford [not Rev. Paul D.], who had a shop in Riviera Beach, Florida, and who imported shells from the Bahamas. Possibly, Ford bought the shell from a fisherman. There are four reasons to doubt that this shell (collected alive) came from 175 fathoms off Hope Town: (1) . Although detritus feeders can live at great depths, I doubt that such a large, herbivorous gastropod (Robertson, 1961) could live at 175 fathoms, well below the photosynthetic zone.^ (2) . The escarp- ment bounding the Little Bahama Bank off Hope Town is precipitous. The margin of the Bank is at a depth of 55-70 fathoms (personal observations) ; soundings of about 1000 fathoms are recorded as near as 5 miles to the Bank (see H.O. chart 0026e) . (3). The currents off Abaco are so strong (2-3 knots) that retrieval of a fish trap from 175 fathoms would be ' Various Strombus species, all smaller than 5. canaliculatus, are known definitely to live in depths of at least 30-43 fathoms, but not deeper. A tiny species has been dredged alive in the Hawaiian Islands between 43 and 66 fathoms (see Abbott, 1960, pp. 83-84) . NAUTILI TS 75(1) PLATE II ligs. 1:1 Siioinhu.s canaliculalus Bmry. Length: 242 NAUTILUS 75(4) PLATE 12 ^ i ^' L.^k Spires of iiialloniu'd, tarinalc Mxnnbus (Ti i<(>i iii.s) i^/iic/.s Linn. MalKima Islands (?) . Fij^. I. Holotype of S. caintlii iihil us lluiiy. Drawing l)v (lilbcrt L. Voss in Burrv (1949). Fig. 2. Pui ported "topoiype" of ,S. raiialirulatus. Same slicll as tliat figured l)\ Olsson & Moore (19(32). Both figs, approx. natural size. April, 1962 nautilus 129 impossible without equipment not available to local fishermen, Avho do not place their fish traps ("pots") outside the reef. (4) . During 3 summers (1953-1955) while collecting shells at Hope Town, 1 was unable to get any information from the local fishermen about the finding of 5. canaliculatus. These fishermen remembered details about shells of commercial value collected years before. In view of these 4 reasons to doubt that the holotype came from 175 fathoms off Hope Town, it is improbable that the other 3 specimens of S. canaliculatus (see Olsson & Moore) came precisely "from the same source [locality]". Olsson & Moore concede that they doubt that the "topotype" figured by them was taken from a fish trap. Lyman (1951) reported that the adult specimen (presumably the "topotype") "was brought in from the Bahamas and delivered to Mr. Burry." Thus, there is no compelling evidence that any of these 4 shells came from deep water, or even from the vicinity of Hope Town. The shell figured by Olsson & Moore, identified by them as 5. canaliculatus, differs significantly from the holotype. Oriented conventionally, the holotype (Plate 12, fig. 1) has a high spiral ridge projecting vertically from each whorl of the spire, forming a deep channel near the suture. A similar ridge projects laterally on the shell figured by Olsson & Moore (Plate 12, fig. 2) ; there is no deep channel. In addition, the spires of the 2 shells are of different heights. In my opinion, the name 5. canaliculatus has been applied to malformed shells of S. (Tricornis) gigas Linn. The holotype of S. canaliculatus (255 mm. long) and the shell figured by Olsson & Moore (242 mm. long) are both the normal size of adult and sub-adult S. gigas. A congenital defect of a small part of the mantle laying down the shell material of the posterior part of the outer lip, or an injury at an early age, would account for all the morphological differences (including the suppression of spines and axial sculpture) , and for the differences in the form of the spiral ridge if the position of the defective part of the mantle varies. There are other striking malformations of S. gigas (see M. Smith, 1940, and M.C.Z. no. 168409; Salisbury, 1953), and similar carinate malformations due to mantle defects occur in many other gastropods (Pelseneer, 1920; for more examples. 130 NAUTILUS Vol. 75(4) see Crosse, 1881; Sykes, 1903; Dautzenberg, 1911). A malformed shell of 5. (Strombus) pugilis alatus Gmelin (Plate 13) corresponds in part to S. canaliculatus. On the last II/2 whorls a vertical spiral ridge forms a deep channel near the suture. Growth was normal until the outer lip was twice broken. La Fontaine (1875) and Abbott (1960, p. 112) discuss 2 more malformed, carinate Strombus, one (S. vittatus Linn.) canali- culate. A simple experiment might prove beyond question that S. canaliculatus is a malformed shell. The appropriate portion of the mantle of juvenile S. gigas could be artificially damaged in order to observe the effects on the subsequently formed outer lip of the shell. In 1951, 2 years after describing 5. canaliculatus and about 11/2 years before his death (in Dec, 1952), Leo A. Burry ad- mitted to William J. Clench and Ruth D. Turner that he then believed he had named a malformed shell. The additional speci- mens were in Burry's possession at that time. Acknoioledgment: Axel A. Olsson graciously pro\'ided the ex- cellent photograph of the spire of S. canaliculatus, and courte- ously allowed me to read the manuscript of his paper co-authored with Donald R. Moore. References Abbott, R. T. 1960. Indo-Pacific Mollusca, 1 (2) . Burry, L. A. 1949. Shell Notes [publ. Frank Lyman, Lantana, Florida], 2:106-109. Crosse, H. 1881. J. Conchyl., 2P;341-342, pi. 11, fig. 3. Dautzenberg, Ph. 1911. J. Conchyl., 55:209, pi. 10, figs. 12-13. La Fontaine, J. de. 1875. Ann. (Mem.) Soc. Malac. Belgique, ;0:21, pi. 2. figs. 1-2. Lyman, F. 1951. Shell Notes, 2:195-196. Olsson, A. A. & D. R. Moore, 1962. Naut., 75:127-128. Pelseneer, P. 1920. Acad. roy. Belgique; classe sciences; Mem. (8vo), (2)5:22, 45. Robertson, R. 196L Notulae Naturae (Acad. Nat. Sci. Philadel- phia) , no. 343. Salisbury, A. E. 1953. Proc. Malac. Soc. London, 30A7AS, pi. 8 Smith, M, 1940. World-wide sea shells, p. 131. Sykes, E. R. 1903. Proc. Malac. Soc. London, 5:260. April, 1962 nautilus 131 VARIATION AND CHANGE IN SURFACE SCULPTURE IN ANOMIA ACULEATA By ARTHUR S. MERRILL^ Surface sculpturing on the shell of Anomia acule.ata Gmelin varies considerably (Verrill and Smith, 187S; Jackson, 1890; Whiteaves, 1901; and Foster, 1937) ranging from smooth to highly spinose. In fact, lacking intermediates, the variants at the extremes could be easily mistaken for separate species. One, ac- cordingly, might expect to find grave nomenclatorial difficulties in the literature but this is not the case. The smoother of the in- dividuals are still occasionally listed with "form" or "varietal" names but it is generally well understood that they are part of a single species complex. With ample material available, this study was undertaken sim- ply to describe the degree and complexity of sculptural variation normally occurring in this species. As the study progressed I foimd that spinosity, if it is expressed, develops at widely differ- ing shell sizes. In the usual lamellibranch, a character which develops in the postlarval form becomes apparent at about the same age in all specimens. But in A. aculeata, this laboratory has individuals whose variability for the characteristic spinosity may be expressed any time after metamorphosis. This paper, then, describes variability in A. aculeata and pre- sents data to show the change in ratio of smooth to spiny indi- viduals with reference to shell size. Methods of Collecting and Measuring. Most of the material used in this study came from navigation buoys stationed in off- shore waters south of Nantucket, Massachusetts. Since buoys are brought in periodically for cleaning and servicing, the many forms of life found attached can be removed for study. Anomia often homesteads the convenient buoy surfaces, after the initial pelagic larval stage, instead of settling in its usual habitat on the bottom. Because smaller Anomia were predominant on the buoys sampled, the bottom was dredged to obtain representatives of the larger adult sizes. A. aculeata usually maintains a suborbicular shape during ^ U. S. Department of the Interior, Fish and Wildlife Service, Bureau of Commercial Fisheries Biological Laboratory, Woods Hole, Massachusetts. 132 NAUTILUS Vol. 75(4) growth. Those which, by some accident of position, meet an ob- stacle in the immediate vicinity assume various distorted shapes in an effort to circumvent the impediments. This apparently does not affect the morphology gieatly other than to shift the axis of growth. The shape may become transversely elongated, or, more commonly, irregularly rounded. Thus, to better indicate true shell size, measurements of both the height and length were taken, added together, and the result divided by 2. Over 4,000 specimens, from newly settled larvae to mature adults, were examined. Variation in surface structure. A. aculeata derives its specific name from the spinous and/or foliaceous character of its surface. While most individuals exhibit some degree of surface ornamen- tation, many individuals are entirely smooth. Foster (1937), reporting on specimens brought up attached to shells from fairly deep water on Georges Bank, described considerable variation in the spines, but, lacking smooth individuals, he did not describe this condition. Verrill (Verrill and Smith, 1873) mentioned vari- ations in A. aculeata from the Bay of Fundy and the Casco Bay areas and described a variety with the scales "more or less absorptive or even entirely absent." Jackson (1890) and Whit- eaves (1901) briefly discussed the smooth form. Plate 14 illustrates the variation found in the surface sculpture of this species. On individuals with well-developed spines, the spines may radiate to the ventral margin at regular, well-spaced intervals. On others, they may be irregularly or more closely spaced. The spines may be seated on raised ridges or may simply arise from the surface. Concentric lines form at intervals as the shell grows. The spines terminate at the line formed at the end of each of these growth intervals, and other spines commence to form with renewed shell growth. The degree of fluted, frilled, or other transverse sculpture depends on the degree of development of concentric processes. For example, on those with closely spaced and conspicuous growth lines, the spines are blunted. Often those with weaker growth lines tend to have spines which project from radiating ridges. The spines may also lack radial symmetry and simply form along concentric lines apparently at random over the shell surface. April, 1962 nautilus 133 On those individuals with smooth surfaces, the concentric growth lines are slightly undidate causing the surface to appear craggy or scaly. Very few have the smooth and glittering surface of the allied species, A. simplex Orbigny; usually the surface appears dull and chalky. Practically every conceivable combination occurs between plain smooth and fully scaly individuals. Those not quite smooth may have faint ridges, perhaps just a ray or two in some; others may have a full fan of strong ridges with no sign of spines. On some with ridges, there may be a raised spine here and there, or possibly one of the ridges will be fidly spined with none of the other ridges showing the slightest tendency to spininess. Some will be smooth to a certain stage in growth, then suddenly begin producing nicely developed spines. Others may do this and then just as suddenly become smooth again. There is seemingly no end to the possible combinations. For the purpose of this paper, the individuals have been separated into two recognizable categories: those lacking surface ornamentation, and those show- ing surface sculpture to various degiees. The latter include individuals whose sculpture ranges from faintly rayed to heavily spinose. Size-frequency data by station: As mentioned earlier, popula- tion samples of A. aculeata were taken from 3 offshore buoys as well as from the bottom by dredging. Table 1 lists the frequency distribution from all stations as well as the percentage of smooth Anomia in each size category. The station locations and other data relating to them are listed below. Nantucket Shoals Lightship Buoy (NSLS). The NSLS buoy, located 1 mile, 55° true, north of the permanent Nantucket Shoals Lightship at 40° 33' N. latitude and 69° 28' W. longitude, was placed on station October 8, 1957. When removed May 10, 1958, it had been in the water for 7 months. An estimated 25,000-30,000 specimens of A. aculeata were attached to the buoy. The sample used for this study consisted of 2,423 specimens. Davis Shoals Buoy (4DS#1). The station occupied by the }DS#I buoy is about 25 miles west-northwest of the NSLS buoy at 40° 57' N. latitude and 69° 55' W. longitude. This buoy was on station 1 year from May 7, 1957, to May 15, 1958. The sample taken from this buoy included 537 specimens of A. aculeata. 134 NAUTILUS Vol. 75(4) T) ti (d m VI ac 3 O O n1 u m N d CO at 3 0) ti 1 C jC :4t 500 o " 0) 2 3 fl( Oj M m <*^ 1 C/} o-w m p No. spec men 1 "S x: n; '^ -*-» >, 500 o ^ a, 0 3 CO 4-« 1 ►J 0 Jh CO CO 0 c ^ 0) N 53 eNjC35«3oot~r~t-oot-oo»-icoino>cDoot- t~ooc^^coM05co^DTl^MtotDTf(^^^-»-l^-«o t~c^mT}<(joi-(t~cot--'i'^cj>-( I CM-HCMMT-tCgCMtOtDinf-ICOOl I I I I c35t-tomiOir5T}H •3 .-ic^co^intDt-oocr50.-ieMcO'«iu.\j piiolli.s aliiliis (.nielin. jiucnile. Shell ct)ated with MgO to show sculptuiL- bin not color pattern. Saiiibel Island (?), Florida, .\merican Miiseiiin ol Xaiinal History (no. 46068). Fig. 1. \]>ical \iew. x'-^"- I'ig- -■ Vix'rtural \iew. Fig. .S. ()l)li(iiic \iew. Figs. 2-3 iiainral size. NAUTILUS 75 (4) PLATE 14 A)iomui nnilctilti C.mcliii. Rcpicsciilativc individuals arranged in show variation in shell stidpturc. April, 1962 nautilus 137 one can easily trace back along the shell and see when spines were first laid down. Although this usually is found to be within the first few millimeters of giowth, as reflected by the graph, it may be found on particular specimens at any size. Even a speci- men of almost maximum size may finally express potential to produce spines. It should be pointed out, in regard to using material mostly from buoys for this study, that the environment on the buoy is probably more uniform than on the bottom. However, the small amount of data from the bottom collections fits in well with the data from buoy samples. This tends to confirm the possibility that variation in surface sculpture in A. aculeata might be a genetic rather than an environmentally induced phenomenon. Conclusion and Summary 1. Surface sculpture in the shell of Ajiomia aculeata varies considerably depending, in part, on size (or age) . The sinface may be smooth or, to a highly variable degree, spinose. A long series of similarly-sized specimens from single buoy samples can be formed in which graded variability in surface structure is shown easily. Therefore, in keeping with the usual procedures in taxonomy, no distinction shoidd be shown the extreme variants. 2. All early post-larval A. aculeata have smooth siufaces and, although a percentage may remain smooth throughout life, many start early to put on spines, the percentage of spiny individuals increasing with shell size. 3. The fact that smoothness is always expressed in the early dissoconch shell implies that spinosity is a natural later develop- ment. The early smooth shell undoubtedly represents the gen- eralized or ancestral form. The generalized form found along the western Atlantic coast is A. simplex, or along the European coast, A. ephippium (type species of Anomia) . Spinosity, a divergence from the generalized, may be considered a derivative. Literature cited Bousfield, E. L. 1958. Proc. Nova Scotian Inst. Sci. 24 (3) : 303-325. 1960. Canadian Atlantic sea shells. National Museum of Canada, Ottawa, 72 pp. Foster, Richard W. 1937. Naut. 50(3) : 102-103. Jackson, Robert Tracy. 1890. Phylogeny of the pelecypoda, the Aviculidae and their allies. Alem. of the Boston Soc. of Nat. Hist. 4 (8) :277-400. 138 NAUTILUS Vol. 75(4) Whiteaves, J. F. 1901. Catalogue of the marine invertebrates of Eastern Canada. Geological Survey of Canada, Ottawa, 271 pp. Verrill, A. E. and S. I. Smith. 1873. Report upon the invertebrate animals of Vineyard Sound and adjacent waters, with an account of the physical features of the region. Report of the U. S. Fish Commission for 1871-72, 448 pp. ENHANCEMENT OF LATENT SHELL FLUORESCENCE BY GLYCERINE By RICHARD G. WOODBRIDGE, III c/o Transspace Laboratory, Box 111, Princeton Junction, New Jersey At the close of a recent period of collecting and experimenting, an interesting observation was made pertaining to the fluores- cence of shells (1) which is deemed worthy of preliminary publication at this time. All specimens were obtained at and below (using scuba) the "low tide line", Northwest Harbor, Deer Isle, Maine, August 28-29, 1961. The ultraviolet light used was one originally de- veloped for underwater work and littoral exploration (2) emis- sion being from a BLB lamp (approximately .8500 to 4000 angstroms) . While attempting to ascertain the suitability of glycerine as a preservative for the color and normal fluorescence of "coralline algae" (3) , a small "limpet" adhering to one specimen was inad- vertently coated with the glycerine, whereupon (in the dark) under the ultraviolet light the limpet shell burst into a strong, glowing, deep red fluorescence. Fifteen living specimens of Acmaen testudinalis testudinalis (Miiller) (limpets) were subsequently either coated with or immersed in glycerine. In every case a deep red fluorescence resulted over the entire shell while under the glycerine. Prior to treatment these specimens had no apparent visible red fluores- cence. Unfortunately time did not permit an examination of the effect of glycerine on the fluorescent areas (feeding?, homing?) surrounding such limpets when they are found living on "bare" rocks — an observation made by the writer some years ago (un- published) . Twenty-seven living specimens of Littorina littorea (Linn^) April, 1962 nautilus 139 (the common periwinkle) were treated with glycerine. In all cases, a similar deep red shell fluorescence of considerable inten- sity resulted, particularly strong in small specimens. Location of the area of maximum shell fluorescence was somewhat variable, appearing to have a tendency to localize in areas in the proximity of the apex. Fifteen specimens kept immersed in glycerine ap- pear to have retained their red fluorescence unchanged for two months. In the case of the periwinkles, the writer has felt for some years that occasionally some sort of dark red shell fluorescence could be observed but it was so illusive and ephemeral that such observations could be considered at best as highly questionable; however, it has led the writer to refer to the phenomena as "enhancement" of fluorescence, rather than, say, "inducement." Vigorous scraping with a knife blade of both limpet and peri- winkle shells subjected to the above glycerine treatment re- sulted in no apparent diminution of shell fluorescence until the shells were deeply abraded — suggesting that the phenomena is not due to a superficial shell coating. Three small, living specimens of Bucciniim undatum Linn^ (the common welk) coated or immersed in glycerine showed no such shell fluorescence. A small specimen of Clanculus puniceus from the writer's col- lection of fluorescent shells showed no particular enhancement of its normal brilliant rose fluorescence. References Woodbridge, R. G. Fluorescent Shells, a Monograph, etc. Pub- lished by Transspace Laboratory, 1961. Ibid. Underwater Ultraviolet Lights, etc. Published by Trans- space Laboratory, 1960. Woodbridge, R. G. and Woodbridge, R. C., The Application of Ultra-Violet Lights to Underwater Research, Nature 184:2b^ (July 25, 1959) . REPRODUCTION OF OLIVELLA MUTICA^ By ROBERT T. PAINE Scripps Institution of Oceanography La Jolla, California Olivella mutica (Say) occurs commonly in warm, shallow ^Contribution no. 171 from the Oceanographic Institute, Florida State University, Tallahassee, Florida. 140 NAUTILUS Vol. 75(4) waters from North Carolina to Texas, and in the West Indies (Abbott, 1954) . However, little appears to be known about its general biology. The following observations are primarily con- cerned with the external form of the egg capsvde, length of the developmental period, and duration of the spawning season. Some data are also presented on the nature of the occupied habitat and population density. This study was made possible through use of the facilities of the Alligator Harbor Marine Laboratory of Florida State University, in Franklin County, Florida. Menzel (1956) has cited O. mutica as a common snail in the immediate region. Olivellas were collected from the south end of a sandbar lying across the mouth of Alligator Harbor. Extensive portions of this bar become exposed at most low tides. Thirty- two snail egg capsules of similar appearance but of unknown parentage were collected, primarily from the valves of a brachiopod which occurs commonly on the bar. All but 7 of these embryos were reared successfully in filtered sea water, and many of them were then maintained until they were suf- ficiently large to be identified. Most were identified from Abbott (1954) and Olsson's monograph (1956) as O. mutica. However, one O. pusilla (Marrat) which is also present at Alligator Har- bor, was subsequently discovered included with the specimens of O. mutica. Because, unfortunately, laboratory-raised and field- collected specimens were mixed, I do not know whether all the eggs were O. mutica, or whether a few might have been O. pu- silla. This confusion of two very similar species will not affect those conclusions based on egg capsules in which O. mutica is known to have predominated. However, no distinction was drawn between these two olivellas in the field and thus the density and habitat information includes both species. Adult snails were noted from September, 1959, to August, I960, indicating year-round occupancy of the intertidal portions of the sandbar's southern end. The bottom sediment here is predominately a mixture of fine-grained quartz sand M'ith an average diameter of 0.125 to 0.250 mm., and a few shells or shell fragments. The silt and clay fractions of the sediment are mini- mal, and little decaying organic matter has accumulated. The marine grass Diplanthera wrightii (Ascherson) , occurring in patches, has consolidated portions of the bottom sediment but has not changed the physical characteristics of the substratum April, 1962 nautilus 141 appreciably. Olivellas were collected from both consolidated and unconsolidated sandy sediment, with the maximum density of 178 snails per square meter in the latter. Snails of this genus were not found in samples from soft bottom areas overlain by quantities of organic material. 670 A 1050/t Fig. 1. Usual egg capsule ot Olivella mutica. The encapsulate eggs of O. mutica (Figure 1) are laid separ- ately, one ovum per capsule, with no trace of nurse eggs, and are attached to any solid object that protrudes above the surface of the sand. The geneial cliaracteristics of the egg and the site of oviposition are thus similar to those described by Marcus and Marcus (1959) for O. verrcauxii (Ducros) . The base of the egg capsule of O. mutica is roughly circular and 1.0 to 1.1 mm. in diameter. From this base rises a smooth, spherical, transparent dome about 670 microns in diameter. Near the top a distinct ridge indicates the line along which the capsule lid separates when the young snail escapes. In general form the capsules ap- pear indistinguishable fiom those figured by Perry and Schwen- gel (1955) for O. pusilla. In contrast, the egg capsule of O. ver- reauxii (Marcus and Marcus, 1959), though entirely similar in gross shape, can readily be distinguished by the surface sculptur- ings — fine, raised, parallel lines. The majority of the eggs of O. mutica were found attached to the anterior end of the valves of the inarticulate brachiopod, Glottidia pyramidata (Stimpson) , with from 1 to 5 capsules per brachiopod. Freshly-deposited eggs or developing embryos were obtained on 25 March and 8 April, 1960, when the water temper- ature ranged from 16° to 20° C. The maximum developmental 142 NAUTILUS Vol. 75(4) period, based on laboratory-reared eggs, was 19 or 20 days for both collections. The cleavage and veliger stages are spent in the capsule, and upon hatching the capsule lid is broken off and a young snail, 750 microns in length crawls away. On the other hand, Marcus and Marcus (1959) have shown that O. verreauxii hatches as a veliger after 8-9 days. Large samples of the brachiopod were also closely scrutinized on 26 February, 10 and 12 March, 22 and 23 April, and 3, 8, 25, 26, and 28 May; they were devoid of Olivella egg cases. The first egg to hatch in the laboratory did so on 6 April. If one extrapo- lates back 20 days, the suggested period of embryonic develop- ment, the initial spawning took place about 17 March. Egg- laying appears to have ceased sometime between 8 and 22 April. These data suggest that O. miitica spawns for approximately one month during the spring, and that egg-laying is closely limited to this period. No information is available on spawning in the fall, or latitudinal variations in the duration of egg-laying. Literature cited Abbott, R. T. 1954. American Seashells. Princeton: D. vanNos- trand Co. 541 pp. Marcus, E. and E. Marcus, 1959. On the reproduction of Olivella. Univ, Sao Paulo, Fac. Filos. Cienc. e Letras, Bol. Zool. 22: 189-199. Menzel, R. W. 1956. Annotated check-list of the marine fauna and flora of the St. George's Sound - Apalachee Bay Region, Florida Gulf Coast. Fla. State Univ. Ocean. Inst., Contrib. 61. Olsson, A. A. 1956. Studies on the genus Olivella. Proc. Acad. Nat. Sci., Philad. 108:155-225. Perry, L. M. and J. S. Schwengel, 1955. Marine shells of the western coast of Florida. Ithaca: Paleon. Res. Inst. 318 pp. PUERTO RICAN OLEACINOIDS By H. BURRINGTON BAKER The symbols used for Puerto Rican localities were explained recently, 1961 (1) . Yunquea denselirata H. B. Baker. Only known from type locality (Er3) ; on last whorl of type (only dry) shell, "very fine" growtli threads average 1 1 microns from crest to crest, which means 91 per mm., and that the "very slightly stronger" ones run 13 to 15 per mm. Y. monteplatonis (Pilsbry) has similar threads. Odontosagda sp. "Yunquea denselirata" van der Schalie, 1948: April, 1962 nautilus 143 71, pi. 6, fig. 5. Probably an unnamed species, from about 3 km. south of Aguas Biienas. The anatomy of Odontosagda is unknown. Although its shell has internal lamellae (like some Sagdinae) , in general form and size, it does resemble more closely that in Yunquea (Yunqueinae). Hyalosagda (Microsagda) subaquila (Shuttleworth) . Among dead leaves in disturbed places. En, Jn, Pn, Prl (2500 ft.) , Wn, Wr2, Ws, Ww2; mainly lowlands. Foot light near sole but almost black above, with lighter middorsal stripe and triangle between ommatophores, which are very dark; eyes light with dark centers. H. (M.) subaquila, var. a. Psl-3; shell more depressed, with larger umbilicus (about I/5 major diameter) . H. (Lacteoluna) selenina (Gould) . Probably distributed by commerce; Es2, Jn, Pn, Pr2-6, Wn, Wr, Ws, 0-3400 ft., but not found in Luquillo forests. H. (Aerotroc/ius?) krugiana (Martens) . Size (1877:346) : 3.5 by 171 (6 mm.) with 5 whorls, subangulate, narrowly umbilicate. Caguana, west of Utuado. Martens compared the last species to the Cuban Helix turbini- formis Pfeifier, which at the time was confused with type species of Aerotrochiis, the Jamaican Hyalosagda subpyramidalis (C. B. Adams) ; the last is a higher, but angulate shell, which lives on trunks of trees. These 3 Puerto Rican species belong in the sub- genus (or genus?) Lacteoluna; Hyalosagda (s. s.) and Stauro- glypta appear to be mainly Jamaican. Aquebana (s. s.) velutina (Lamarck) . Living animals very rare, under rocks, 5-6 inches below surface (Jnl) and under dead leaves between limestone ledges (Enl) during and at end of drouth, but dead shells numerous (Jn2) which may indicate that it has periods of abundance. Fresh shells with greenish tinge. To 1940c: 59, is added: foot pale, with chrome spots, obscured by chalky ones. Platysuccinea portoricensis (Shuttleworth) . Terrestrial, under upper layer of dead leaves, especially in ruderal places; Er, Pr, Wr, 1500-4000 ft. Fresh shells, with adherent dirt except in columellar region, greenish corneous on El Yunque and often with very low spires, but often more hyaline with higher spires in Cordillera Central. Animal (added to 1940c:61) rather slug- gish; side of foot very warty, ochraccous to brown, darker in wrinkles, dorsad and on ommatophores; mantle collar not over- lapping peristome but with umbilical lobe over columellar area; sole dark slate, only trizonal, with numerous rapid waves in middle zone. P. portoricensis, var. a. Under rocks, Enl; also empty shell from Pnl ; less than 200 ft. Shells much smaller, more hyaline and 144 NAUTILUS Vol. 75 (4) with higher spires, but not distinguishable from young ones from Cordillera Central; also quite similar in form to "Simpulopsis" aenea Pfeiffer, 1861, as figured by Fischer & Crosse, 1877, Miss.. Mex. Moll. 7;pl. 24, figs. 12; "S." cumingi Pfr., P. Z. S., 1861:pl. 3, fig. 2, from Mexico, looks like typical P. portoricensis (some El Yunque shells even larger) ; and ruderal snails do get around. Varicella (Vagavarix) portoricensis (Pfeiffer) . Terrestrial; En, Es, Jn, Pn, Pr3,6, Wn, Wr2,3, Ws, 0-3000 ft., but not found in Luquillo Mts. V. (Vagavarix) calderoni H. B. Baker. On ground; Pr6, Wr2, 2000-3000 ft., Cordillera Central. V. (Vagavarix) sulculosa (Shuttleworth) . Terrestrial; En, Es, Jn, Pn, Pr 1,5,6, Ps2,3, Wn, Wr, Ww, 0-4000 ft., but not found in Luquillo Mts. Larger lots intergrade completely with smoother form terebraeformis (Sh.) , which has more widely and irregu- larly spaced growth striae; mostly size of sulculosa but one (Ps2) 12.1 mm. long with 8.2 whorls. V. (Vagavarix) sporadica H. B. Baker. On ground; Es3,4, Er2, 200-2500 ft., only found in eastern Puerto Rico. Oleacina (Laevaricella) interrupta (Shuttleworth) . Usually subarboreal, but also seen alive under leaves at base of trees; Er2, Pr2,3, Wr2,3, 2000-3400 ft., ranging from Luquillo Mts. to western Cordillera Central. Animal (1941b:29) seen attacking Nenia; lateral zones of foot narrow. Oleacina (Boriquena) glabra (Pfeiffer, 1846) . Terrestrial, Er2- 5, above 2000 ft. in Luquillo Mts. O. (B.) playa (H. B. Baker) . On ground; En, Es3, Jn, Pn, Wn, Ws, lowlands, 0-800 ft. This "large, elongate, smooth species com- mon to Puerto Rico" first noticed and called "gracilior" by Shut- tleworth, 1854:51; all I did (1940a) was to prove it a distinct species and name his "var. beta" in Varicella; if his descriptive term be considered a trinomial, it would be preoccupied in neither Gla7idina nor Oleacina. Although the animal of Oleacina s. s. is still unknown, Bori- quena (possibly only a section) and Laevaricella (a very distinct subgenus) now are made congeneric with it, because of the close resemblance in the embryonic shells of Oleacina, Boriquena and Varicella s.s., which was pointed out by Pilsbry, 1907 (12a): 127, and because the differences in shell form between O. voluta (Gmelin) and O. (voluta var.?) flexuosa (Pfr.) from Haiti so closely parallel those between the Puerto Rican O. glabra and O. playa. In 1956:133, 135, after vacillating in I941d and 1943c, the almost strictly Antillean Oleacinidae (-f Varicellarum) , with 1 Cuban species in Florida, were separated from the Spiraxidae (including Streptosylinae and Euglandininae) , which are most April, 1962 nautilus 145 differentiated on the mainland, but have invaded Jamaica (Spir- axinae) and other Antilles [Streptostylinae: Salasiella (Laevolen- cina & Flavoleacina), Streptostyla (Rectoleacina), etc.]. These two families have almost nothing in common except their carnivorous habits and the correlated convergences in the radulae of their most specialized groups. Even in their radulae, the Spiraxidae almost intergrade with the Achatinidae (sens. lat.) , which also have little epiphallic differentiation and some- times (Ferussaciinae) have similar "heterurethrous' " pallial com- plexes. The changes in the radulae within Varicella (especially Melaniella) show that the convergences (uniformly aculeate teeth) have come from different sources, and the Oleacinidae have sigmurethrous pallial complexes and truly penial epiphalli, often with well developed verges, much more like those in the Sagdidae. The unroofing of the adrectal limb of the ureter, which is paralleled in both the Oleacinidae and the bigger Spiraxidae (and in many other groups of geophiles) is found also in Yunquea, which has the most generalized radula in the oleaci- noids. Incidentally as far as known, outside the small species of Hojeda, and the riideral Hyalosagda selenina and (possibly) Platysuccinea, the Sagdidae also seem to be restricted to the Antilles. Additional references (see 1962) 1961 (1), Naut. /•/ .-142-149. 1962, Naut. 75:116-122. RADULAE OF NORTH AMERICAN ANCYLID SNAILS II. SUBFAMILY NEOPLANORBINAEi By PAUL F. BASCH Department of Biology, Kansas State Teachers College, Emporia The subfamily Neoplanorbinae was established by Hannibal (1912) to accommodate 5 species in two unusual genera of fresh- water mollusks. These species demonstrate an extreme in endem- ism, all known specimens having been collected from the lower Coosa River bordering Coosa, Chilton, and Elmore counties in central Alabama. As far as I am aware, only t^vo men, H. H. Smith and A. A. Hinkley, have ever seen these animals alive, and it is unlikely that living specimens will be seen by anyone else. The first mention of these snails was by Hinkley in 1904, who listed both "Planorbis tnntillus Pilsbry" and an undescribed ' Supported by grant G-14125 from the National Science Foundation. 146 NAUTILUS Vol. 75 (4) form, "N. g., n. sp." among a group of Alabama shells collected the previous year. Pilsbry (1906) recognized these shells as ". . . quite unlike any fresh-water snails hitherto known in this country, having affinities with the Ancylidae." He established two new genera for them, describing Amphigyra alabamensis and Neoplanorbis tantillus as new species. Two years later. Walker (1908) named 3 additional species of Neoplanorbis: N. cari- natus, N. umbilicatus, and N. smithii, and these have remained, without change or addition, to the present. In 1914 Lay Dam, the first of a series of major hydroelectric power installations, was completed across the Coosa River be- tween Coosa and Chilton counties, 13 miles east of Clanton, Ala- bama. This dam imponds an area of 6,000 acres, with a back- water extending to a point 13 miles below Childersburg (Pierce, 1955) . Sixteen miles downstream Mitchell Dam was completed in 1923, with 5,800 acres of backwater extending to Lay Dam. In 1929, Jordan Dam was built 8 miles north of Wetumpka, Elmore County. This dam supports a lake of 4,900 acres, extend- ing about 18 miles upstream to Mitchell Dam. The large lakes formed by these dams, which provided power and recreational facilities for the people of central Alabama, also destroyed the habitats (and presumably caused the extinction) of all known species of Neoplanorbinae. These tiny mollusks lived on stones in the swift current of the Coosa (See Goodrich, 1944) , in localities now covered by many feet of impounded lake water. An attempt in June, 1959, by the author and Dr. John B. Burch to find living specimens in the Coosa was not successful (Basch, 1959) . Through the kindness of Dr. Henry van der Schalie of the Uni- versity of Michigan Museum of Zoology I have been given access to the specimens of Neoplanorbinae in his care, with permission to extract and prepare radulae from a sample of the specimens. The radulae were extracted and mounted using techniques out- lined in a previous paper (Basch, 1961) . A study of these radulae was undertaken in an attempt to learn more about the systematic position of the Neoplanorbinae by comparison of their radulae with other groups of Bosommatophora. In Neoplanorbis, the shell is planorboid and extremely sim- ilar in conformation and dimensions with shells of Micro- menetus of the family Planorbidae. Since Menetus (Micro- April, 1962 nautilus 147 menetus) alabamensis is known from the state, 1 considered that possibly Neoplanorbis represented a special group of Menetus- like planorbid snails. Ecologically, Menetus is an inhabitant of quiet, plant-filled pools in a situation vastly different from the rocky rapids of the old Coosa River. Shells and radulae of Micromenetus are illustrated by F. C. Baker (1945). The following radulae have been prepared (UMMZ numbers): #102672 — A^ tantillus, 2 specimens. #102664 — N. carinatus, 2 specimens. #102671 — ^A^. smithii, 2 specimens. The species studied were all similar in radular characters. Neo- planorbis tantillus, carinatus, and umbilicatus are obviously closely related on the basis of shell similarities and may in fact represent a single variable species. The radulae of A^. tantillus and N. carinatus are indistinguishable (it was not possible to obtain a suitable specimen of A'^. umbilicatus). Neoplanorbis smithii, whose shell is easily differentiated from the other three by its lack of spiral sculpture, has a radula differing in minor characters, particularly the angle formed by the medial surface of the lateral teeth with the longitudinal axis of the ribbon. In all three species of Neoplanorbis the radular formula is 17-1-17, with the inner cusp of the laterals long and dagger-like, bearing a small accessory cusp on its medial surface. The marginal teeth are characterized by an increasingly rectilinear upper edge and a prominent needle-like cusp located just medial to the center of the tooth (Page 148, Figs. 1 and 2) . The extreme smallness of these teeth must be pointed out, for some of the finer features lie beyond the resolving power of a light microscope. The optical equipment used in this study consisted of a Leitz triocular Labolux microscope with a lOOX N. A. 1.30 oil immersion ob- jective and paired 20X oculars. An internal prism factor of 1.25X provided a final magnification of 2500X. Even at this extreme magnification, some details were not readily distinguishable in the bacteria-sized teeth. The radula of Amphigyra is strongly bicuspid (cf. Pilsbry, 1906) and similar to that of Neoplanorbis. The formula is 18-1-18, and lateral teeth 7 to 11 resemble planorbid and some ancylid laterals rather closely (Page 148, Fig. 3), perhaps estab- lishing a point of homology. Two radulae were prepared from 148 NAUTILUS Radulae of Neoplanorbinae. Fig. 1, N. carinatus Walker; Fig. 2, A^. smithii Walker; Fig. 3, Amphigyra alabamensis Pilsbry. specimens in UMMZ lot #\Q2Q11. Judging by the radula, apparently Amphigyra and Neoplan- orbis are closely related to each other, but they have diverged considerably from other groups of Basommatophora. With April, 1962 nautilus 149 a dearth oi anatomical data concerning the Neoplanorbinae, its position within the Ancylidac is not firmly supported by radular structure alone, but no other evident relationships are revealed. Literature cited Baker, Frank C. 1945. The Molluscan Family Planorbidae. Urbana. Univ. of Illinois Press. 530 pp. Basch, Paul F. 1959. The Coosa Revisited. Amer. Malac. Union Annual Rept. for 1959: 17. 1961. Radulae of North American Ancylid Snails. I Sub- family Rhodacmeinae. Naut. 75:97-101. Goodrich, Calvin. 1944. Naut. 5.9 (1) :11-15. Hanibal, Harold. 1912. Proc. Maloc. Soc. London. 70:1 12-211. Hinkley, A. A. 1904. Naut 18(5) :54-57. Pierce, Laurence B. 1955. Hydrology and surface-water resources of east-central Alabama. Geol. Surv. of Alabama, Special Rept. 22:1-318. Pilsbry, Henry A. 1906. Naut. 20 {5):49-5\. Walker, Bryant. 1908. Naut. 2/ (1 1): 126-129. GONAD DEVELOPMENT AND SPAWNING OF BRACHIDONTES RECURVUS IN CHESAPEAKE BAY By J. FRANCES ALLEN* National Science Foundation, Washington, D. C. The hooked or curved mtissel, Brachidontes reciirvus (Rafin- esque) of the family Mytilidae, occurs in large numbers on oyster bars in the tipper Chesapeake Bay and its tributaries. This species is an important fouling organism on oyster bars and affects the growth habits of the oyster. It was reported by Frey (1946) as forming much of the cultch on oyster bars in the Potomac River where most of the marketable oysters weie completely covered with mussels. As a result, the oysters were misshapen from grow- ing among the mussels. Beaven (1947) states that this species is most abundant on bars of the upper portion of the Bay and its tributaries where the salinity is low. Under the name Mytilus recurvus, this species has been re- ported (Nelson, 1928a) as occurring along the New Jersey coast. Chestnut (1949) noted the appearance of the curved mussel in North Carolina. Englc (1945) observed that the hooked mussel, Mytilus Jiaynatiis Say, was present on oyster bars in Alabama, * Work done while with the Department of Zoology, University of Mary- land, College Park, Maryland. 150 NAUTILUS Vol. 75(4) and later (1948) the same investigator reported its presence on bars in Mississippi and Louisiana. According to Abbott (1954) the geographic range of Brachidontes recurvus is Cape Cod to the West Indies. Despite the wide distribution of this species and its impor- tance as a fouling organism on oyster bars, a survey of the lit- erature reveals that with the exception of the observations on distribution previously mentioned, little information is available concerning its biology. This situation is in sharp contrast to that existing in regard to other mussels, such as Mytilus edulis Linne; Mytilus calif ornianus Conrad; Modiolus demissus (Dillwyn) ; and Modiolus modiolus (Linne) , where considerable data are avail- able on numerous aspects of the biology of the species. The investigation reported here was part of a cooperative pro- gram between the Department of Zoology of the University of Maryland and the Shellfisheries Investigations of the United States Fish and Wildlife Service, located at Annapolis, Maryland. Appreciation is expressed to Dr. Robert A. Littleford for his suggestions and criticisms; and to Mr. James B. Engle and Staff of the Fish and Wildlife Service for collection of materials and for data on temperature and salinity. Procedure: Specimens of B. recurvus used in this study were collected from Hackett's Bar, located on the western side of upper Chesapeake Bay and approximately two nautical miles north of the Severn River. This bar is 1/2 to % of a mile offshore from Hackett Point, in water varying in depth from 2 to 35 feet. Sam- ples were taken at two week intervals from January 16, 1950' through April 16, 1951, except when prevented by weather con- ditions or mechanical difficulties with the boat. All the mussels were collected with a standard oyster dredge from the same gen- eral location on the bar and at a depth of 16 feet. With the shell closed and the specimen held in a lateral posi- tion (Newcombe and Kessler 1936), shell dimensions were measured to the nearest tenth, using a sliding vernier caliper calibrated in millimeters. The dimensions used are defined as follows: length, the greatest distance between the anterior and posterior ends of the shell; width, the greatest distance between the dorsal and ventral edges; and thickness, the greatest distance between the right and left valves. The term height is commonly I April, 1962 nautilus 151 used in place of thickness as a more meaningful designation. Specimens of the entire size range were selected from each collection for microscopic study. The individuals were fixed within the shell by severing the posterior muscles and then drop- ping the entire animal into Bouin's alcoholic fixative (Galigher, 1934) . Other fixatives were tried but Bouin's proved most satis- factory. After fixation for several days, they were removed from the shell, washed in 70% alcohol and then stored in 80% alcohol. They were dehydrated in alcohol and xylol, embedded in Tissue Mat, sectioned at 10 micra, stained with either Harris's hema- toxylin and eosin or Mallory's triple stain, and mounted in balsam. Plankton samples were collected simultaneously with the col- lection of mussels by pumping 100 liters of water from just above the bar through a No. 20 silk plankton net. Each sample was concentrated to 100 ml. and preserved with formalin. Examina- tion of these samples to determine the presence or absence of mussel larvae was made with a Sedgewick-Rafter Cell (Little- ford, Newcombe, and Shepherd, 1940) . Obseiuations. The gross microscopic morphology of the curved mussel is identical with that of Mytihis edulis as described by Field (1922) . However, the alimentary tract is sunounded by the visceral mass which contains the other organ systems of the animal. Immediately surrounding the stomach and intestine is the so-called liver, or digestive diverticula. The latter structure also extends into the mesosoma, which is an elongate, ventral extension of the visceral mass, except during the period of gonad development, when the mesosoma is filled with the gonad tissue. The gonadal tissue of B. recurvus consists of a series of ducts and canals, lined with germinal epithelium, which end in pockets or follicles. The mature tissue occupies almost the entire mantle (Plate 15, fig. 4) and the mesosoma to the edge of the foot and penetrates into the digestive diverticula, where it is found ad- jacent to the so-called liver canals, the stomach, and the direct and recurrent intestine. Apparently the early gonad development begins in the mantle and then spreads into the mesosoma. The vesicular tissue which fills in between the follicles is replaced by the gonad tissue as it matures. Thus, when the sex cells are mature, nearly the entire structure of the organism is devoted to 152 NAUTILUS Vol. 75(4) reproduction. As sexual maturity approaches, the mantle and mesosoma become either a bright yellow or a stippled brown in color. The craved mussel is dioecious, and of the 896 specimens exam- ined, there was no indication of the existence of hermaphrodit- ism or alternation of sex. The gonads of both male and female show parallel development in time and in the position of the gonads. From those studied, the sex ratio apparently is evenly distributed. The reproductive potential of these mussels is de- termined by their size rather than by their age. Studies were made of those forms which were as small as 20 mm. in length, and their gonad tissue had the same appearance as that of the larger specimens. Presiuiiably they produce as many reproducti\c cells as their anatomical structure will allow. This also leads to the conclusion that sexual maturity occurs the summer following setting, regardless of size of the mussel. Seasonal Developmerit in the Male. The male follicles vary a great deal in size, depending upon whether the immature or mature condition is observed. From January until mid-April, the follicles are found in tlie mantle, and to a lesser decree, in the mesosoma. They appear at this time to be loosely filled with cells, but by mid-April they become more dense in appearance and they take a deeper and a darker stain (Plate 15, fig. 1) . As they mature, the follicles become filled with spermatozoa which ra- diate from the periphery of the follicle toward the center (Plate 15, fig 2). These cells appear as small oval or spherical bodies which are packed too closely together for their detailed structure to be clearly visible. They matiue by June and remain mature until October. Observation on the density of the sex products in the follicles leads one to believe that spawning may occur from the mantle first, then proceed from the mesosoma. However, the appearance indicates that the animal could very well spawn simiUtaneously from both areas. Spawning from each follicle ex- tends over a considerable period of time so that some follicles do not have the appearance of being spent, while others are mature. As the follicles mature, there are light, radiating areas, which under increased magnification show that the cells adjacent to these areas are concentrated in short rods, apparently similar to the condition observed in Mytilus edulis (Field, 1922). April, 1962 nautilus 153 While the follicle increase in size and maturity, the supportive vesicular tissue surrounding them gradually disappears almost completely. After spawning, the supportive tissue again appears, filling the spaces between the spent follicles. Seasonal Development in the Female. The immature follicles of the female are separated by vesicular connective tissue and vary in size. By the first week in May, the follicles are lined with small cells containing nuclei which with hematoxylin and eosin stain a dark blue. By the third week in May, the cells have in- creased in size so that the prominent nucleoli can be seen, but the cells are still immature. By mid-June, the mantle and the mesosoma are occupied by follicles which are filled with mature and immature eggs (Plate 15, fig. 3) . Some of the vesicular sup- portive tissue is present, but has decreased considerably or dis- appeared as the eggs approach maturity. The eggs vary a great deal in size and the nucleoli are large and prominent (Plate 15, fig. 3) . When the eggs mature, they break from the follicle and are inoved along by ciliated ducts. The eggs are not considered mature until they break free. As is the case in the male, the female gonad tissue penetrates into the digestive diverticula and is in close proximity to the liver canals. (Plate 15, fig. 3) . The condition of the gonad from July to October is similar to that in Jime. After October, however, the ova are not as numerous and some retain the same appearance as those of June. On July 3, the small eggs appeared in the mantle and the larger ones in the mesosoma which contained many follicles. In one specimen from the September group, one lobe of the mantle contained only a few eggs, while the other lobe and the mesosoma were dense with them. Although the condition of the maturity of the ova is such that the entire gonad tissue is subject to spawn- ing at the same time, the intensity of spawning and the time of spawning of these different areas depends upon the individual. Mature eggs are present in December, but show evidence of degeneration or death, as shown by the condition of the nucleus, the absence of nucleoli, and the general appearance of the cyto- pla.-,m. WHiile the destruction of the gonadal tissue appears evi- dent, there is no similarity to the comparable mechanism of re- sorption noted in some pclccypods by Loosanoff and Davis (1951). 154 NAUTILUS Vol. 75(4) The development ot tlie gonads indicates that the state of sex- ual maturity exists from June through October. Release of the sex products occurs over a relatively long period of time, from early June through October, and in some cases, through Novem- ber. Individual follicles develop independently of each other in both sexes. In other words, the gonads do not reach a high peak of maturity and immediately spawn out. Seasonal Distribution of the Larvae. Plankton samples col- lected from January 16, 1950, through April 16, 1951, were ex- amined to determine the presence, relative abundance, and stages of development of the larval forms of B. recurvus. Since the rate of development of the larval stages shows con- siderable variation, in part, at least, because of the protracted spawning period, I decided to divide the forms present into three groups: pre-hinge stage, hinge stage, and post-hinge stage. The hinge stage was defined as "the straight-hinge-line embryonic shell" (Field 1922), between the circular immature larval stage and the triangular ovate form of the mature larva. In the area of Hackett's Bar, the larval stages of this species could be con- fused only with the larval stages of Congeria leucophaeta, Cras- ostrea virginica, or possibly with Tagelus plebeius and Mya arenarin. However, as is pointed out by Sullivan (1948) , care- ful examination will show numerous diagnostic differences be- tween the mussel larvae and other lamellibranchs. Therefore, the larval stages of different groups may be easily separated from each other, although some confusion might possibly arise in regard to the larvae of Brachidontes recurvus and that of Con- geria leucophaeta. However, considering the rare occurrence of the latter form on Hackett's Bar, such confusion should not invalidate the data. The results of the observations on larval distribution are pre- sented in Table I. The relative abundance of the various larvae is expressed as present, common abundant, and very abundant, rather than by using some numerical statement. I felt that such an expression of results had more validity than an exact numer- ical expression, since the method of collection was not subject to exact quantitative analysis (Littleford, Newcombe, and Shep- herd, 1940). Larvae appeared in the plankton for the first time on June 5, April, 1962 NAUTILUS 155 TABLE I SEASONAL OCCURRENCE OF URVAE OF BRACHIDONTES RECURVUS IN PLANKTON SAMPLES Date Pre-hinge Hinge Post-hinge June 5 Present Present Absent June 19 Coramon Cornmon Present July 3 Ganmon Ccnnion Common July 17 Absent Present Present July 31 Abundant Present Absent August 14 Ccramon Common Absent August 28 Abundant Abundant Abundant Sept. 11 Very Abundant Very Ab'jndant Very Abundant Sept. 25 Common Present Cormon October 9 Present Absent Common October 25 Absent Absent Present Nov. 13 Present Common Contnon Nov. 27 Absent Absent Present Dec. 11 Absent Absent Present 1950 when pre-hinge and hinge forms were observed in the samples. By the middle of June, the pre-hinge and hinge stages had quadrupled in number over the earlier part of the month. The post-hinge stage was observed for the first time on June 19, 1950. During July and August there was, generally speaking, a continued rise in abundance of the larval stages. However, the pre-hinge stage was not found on July 17, 1950 and the post- hinge stage was not observed in collections of July 31 and August 14. All three stages were present in large numbers in the collec- tion of August 28, and the peak of their numerical abundance in 156 NAUTILUS Vol. 75(4) the plankton was ob,ser\cd on September 11, 1950. Some idea of the relative seasonal abundance of the larval stages may he obtained from the fact that the number of pre- hinge larvae in June was 27.50% of the total number observed on September 11. Similarly, the number of the hinge larvae in June was 15.15% and the number of post-hinge was 0.54% of the total observed on September 1 1 . (To be concluded) AUSTRALORBIS ALBICANS (PLANORBIDAE) Bv W. LOBATO PARAENSE and NEWTON DESLANDES' Institute Nacional de Endemias Rurais, Brazil This species was described by Pfeiffer (1839, p. 354), on the basis of the shell characters, as follows: "43. Planorbis albicans Pfr. — Testa orbiculari, utrinque um- bilicata, solidula, albicante vel pallide fulvicante, anfract. 3 teretibus; labro subincrassato albo; apertura subovata. — Diam. 21/2, alt. 1'". — Dem PI. albus (hispidus) am nachsten verwandt." Clessin's desauption (1884, p. 119-120) is more detailed and extends the species range to other Antillean islands: "87. Planorbis albicans Pfeiffer. Taf. 11. Fig. 14. T. depressa, utrinque centro profundissime immerso; subtiliter striatula; lutida, pallide-cornea; anfractus 4, rapide accrescentes, rotundati; superius valde convexi, sutura profundissima separati; inferius planulati, sutura paulo immersa disjuncti; idtimus penultimo paulo latior, aperturam versus descendens; apertura late-lunata, albo-labiata, valde obliqua; peristoma acutum, marginibus con- junctis. Diam. 5,5, alt. 1,8 Mm. Planorbus albicans Pfeiffer Wiegm. Archiv I 1839 p. 354. Planorbus albicans Reeve conch. Icon. XX f. 117. (?) Gehause gedriickt, ober- und unterseits in de Mitte tief eigenesenkt, sehr fein gestreift, glanzend, hellhornfarben, Um- gange 4, rasch zunehmend, nach oben sehr gewolbt und durch eine sehr tiefe Naht getrennt; nach unten flacher und durch eine seichtere Naht verbunden; der letzte Umgang nur i/gmal breiter als der vorletzte; gegen die Miindung etwas herabstei- gend; Miindung breit-mondformig, weissgelippt, sehr schief; Mundsaum scharf, mit verbundenen Randern. Vaterland: Die ^ Work made in cooperation with Institnto Oswaldo Cruz and Service Especinl tie Saiulc i'uhlica. Aided by the C'onsellio Nacional de Pes(|uisas of Brazil, which defrayed the expenses of a trip by the senior author to the type locality of A. albicans and also provided additional facilities for the study of the material collected there. NAin ILIIS 75(4) PLATE 15 I. Ii)(i( liidoulcs icrun'us in niicl-A|)ril. Imiiuiuirc t'ollicles of (lie male I^oiukI in the niaiitle. H. and E. slain. X2l)(). 2. in June. Male follicles lilled with spermatozoa. Note the i^adiation from the perijiheiN of the follide lo ihe (enter, (iross section through the niesosoma. Malloi\'s Triple slain. \2()(). 3. in mitl-Jiuie. Matiue female follicles adjaceni lo the so-called liver canals in the di;^esti\c di\erli( iila. H. and I-',, stain. X2()U. 4, in Jidy. General view of cross section in region of the gills. Note the presence of mature and im- mature eggs and the prominence of the nucleoli. H. and E. stain. X50. NAUTILUS 75(4) PLATE 16 Fig. 1: Shell of Auslralot his albicans horn Laguna Somorostro, Havana, lig. 2: Raclula teeth of Aiislralorbis albicans from Lagiina La Canoa, Pinai del Rio {C'. = central, I intcinicdiale, L ^ lateral, M - marginal). Fig. 3: (ieiiital organs of Australorbis albicans from I.agiina La C.anoa. Pinar dci Rio (ag= fragment of albumen gland, ta ^ carrefoin-, ng - nidamenlal gland, od " proximal segment of ovispermidnct, od' = distal segment of ovispermiduct, ot - ovotestis, o\ ^" oviduct, po = pouch of oviduct, pp = prepuce, pr ^ prostate gland, ps = penis sheath, rm = retractor muscles of penial complex, sd - spermiduct, sp - spermatheca, .sv = seminal vesicle, ut = uterus, va - vagina. \tl \as deferens). April, 1962 nautilus 157 Antillen, liisel Cuba, bei Cardenas; Portorico, St. Thomas. (Coll. Dunker) . Die Art gehort zur Sect. Armigerus, welche durch im Innern der Umgange angebrachte Zahne und Lamellen ausgeszeichnet ist. — Diese sitzen (meist zu 2 oder 3 an der Miindungswand, und zu 3 an der gegeniiber liegenden Gaumenwand) und zwar in ziemlicher Entfernung von der Miindung, so dass sie gewohnlich erst beim Zerstoren des Gehauses zu entdecken sind, wenn sie nicht durch die Umgange durchscheinend von aussen an der weissen Farbe erkannt werden. Auf der Miindungswand steht gewohnlich in de Mitte derselben ein grosserer starkerer Zahn, dem nach unten gegen die Ecken ein kleinerer sich anreiht. Auf der Gaumenwand befindet sich in der Mitte eine lamellen — oder faltenartige Schmelzleiste, wahrend zu beiden Seiten dersel- ben in nahezu gleicher Entfernung von ihr und etwa in der Mitte des Raumes von der Mittelleiste bis zu den Anschlussecken zwel Hocker — oder zahnartige Schmelzstiickchen angebracht sind. — Ueber den Zweck dieser Gehauseverstarkungen fehlen bis jetzt noch Beobachtungen." Among the planorbids collected by the senior author in Cuba, in December, 1956, there were specimens whose shell agreed, in shape and dimensions, to the two above transcribed descriptions, inclusive as to the apertural lamellae. Some of them, dissected for previous observation, proved young forms of a species anatomically undistinguishable from Planorbis peregrinus Or- bigny, 1835. As then shown (Paraense and Deslandes, 1958b), the shape of the shell underwent a process of remodelling along with growth, with eventual resorption of the five lamellae. A sample from Puerto Rico, sent us by Drs. F. F. Ferguson and Charles S. Richards in 1959, and regarded by them as albicans, was conchologically similar to the aforesaid Cuban material, but the specimens stopped growing when they reached about 7 mm. in diameter, developed permanent lamellae and showed remarkable anatomical differences. Those facts led us to examine our remaining material, among which we found 1 1 specimens anatomically similar to the Puerto Rican ones. Of such specimens, 7 were collected at Laguna La Canoa (between Artemisa and Mangas, Candelaria, Province of Pinar del Rio), and 4 at Laguna Somorostro (Havana) . The largest specimens were 5 mm. in shell diameter, and only two from La Canoa showed apertural lamellae. Taking into account Pfeiffer's and Clessin's descriptions, and 158 NAUTILUS Vol. 75(4) the fact that we are dealing with topotypic specimens, we agree with Drs. Ferguson and Richards in considering this species as Phinorbis albicans. Since the generic problem of the group to which it belongs was submitted to the International Commission on Zoological Nomenclature, the species is here placed in the genus Aiistralorhis, according to the reasons presented by Para- ense (1961). The following description is based on the above-mentioned Cuban material, of which four shells and one dissected specimen were deposited in the collection of Instituto Oswaldo Cruz (No. 7907) . Description: The empty shell (PI. 16, fig. 1), is yellow or amber, finely oblicjuely striate, has about 31/9 whorls, and usually shows 6 internal lamellae deeply situated in the apertural region. The whorls widen rapidly, but at the region of the lamellae they stop expanding or even slightly decrease, and then rapidly widen toward the opening. The outer whorl shows various degrees of downward deflection at the apertural region. The upper (right) side is flattened and deeply umbilicate. It shows round smooth- walled whorls, of which the inner one is obscured at the bottom of the umbilicus. The under (left) side is concave and has a vortex-shaped central depression shallower than the umbilical one. On this side the whorls are bluntly carinate and the inner whorl is plainly visible at the bottom of the central depression. The aperture is directed forwards in young specimens, but as the shell grows larger the lamellae arise and gradually develop, and the aperture gradually bends downwards. In older specimens a callous thickening of the lip may be found. A complete set of lamellae consists of two parietal and four palatal units. Not only as concerns the lamellae, but also the shell, this species is similar to Australorbis janeirensis (see Paraense and Deslandes, 1956), and to young A. glabratiis and A. peregriniis from some popula- tions whose specimens may develop, at early age, a transient set of apertural lamellae (Paraense, 1957; Paraense and Deslandes, 1958b). The animal shows no appreciable difference from that of other small species of the genus. The pseudobranch is simple, thin and flat. The rectal ridge extends from the pseudobranch into the April, 1962 nautilus 159 pulmonary cavity, disappearing at the level of the stomach. There is no renal ridge. A dorsolateral ridge, facing the rectal one, runs parallel to the left side of the renal vein. The genital organs are shown in fig. 3. The ovotestis is composed of numerous sac-like diverticula, which are nearly always simple and less frequently bifurcate. The diverticula open into the ventral collecting canal, which con- tinues into the thin proximal segment of the ovispermiduct. Then follows the seminal vesicle, whose parietal diverticula are poorly developed, as in A. philippianus (see Paraense and Deslandes, 1958a). The seminal vesicle gradually merges into the distal segment of the ovispermiduct, which is about 3-4 times as long as the proximal segment. The spermiduct, highly sinuous at the beginning, follows a flexuous course in contact with the oviduct and, then, traverses the furrow formed by the pouch of the oviduct. At the point where it emerges from that furrow, it receives a single row of prostrate diverticula. The number of diverticula varied from 8 to 16 in our material. They are mainly bi- or trifurcate, less fre- quently unbranched or arborescent. Although some of them have a short stalk, they are mostly sessile, their branches arising al- most directly from the prostate duct. The prostate duct continues into the vas deferens, which has no special characteristics. The penis sheath varies from a little longer to about 4 times as long as the prepuce. It contains a penis that shows no essential differences from that of congeneric species. The prepuce is only a little wider than the penis sheath and is internally separated from the latter by a muscular diaphragm. The oviduct is similar to that of other congeneric species, also having a large pouch of bosselated walls. The nidamental gland and uterus, taken conjointly, are from one and half times to thrice as long as the oviduct. The vagina is tubular and smooth- walled. The spermatheca is pear-shaped or club-shaped and has a narrow duct about as long as the spermathecal body. The jaw is somewhat T-shaped, consisting of a wider upper piece, vertically striate, and two narrower lateral pieces. The fol- lowing characteristics were observed in 5 specimens from Pinar del Rio (fig. 2) : radula formula, 14-1-14 to 15-1-15; horizontal rows, 80 to 90; central tooth bicuspid; 4 to 6 laterals, 2 to 3 160 NAUTILUS Vol. 75(4) intermediates, 6 to 8 marginals. Comparison loitli related species: In a conchological diagnosis between A. albicans and other congeneric species, there will al- ways be place for uncertainty. In fact, even if no doubt arises as to the distinction between adult A. albicans and young shells from large species of Australorbis, there remain to be considered the similarities between the former and other lamellate shells. Of the Neotropical species studied by us, the adult A. janeirensis is always provided with a permanent set of apertural lamellae (Paraense and Deslandes, 1956) . Under special environmental conditions, young individuals from other species, such as A. glabratus and A. peregrinus, may develop a transient set of lamellae which are resorbed as the shell grows larger (Paraense, 1957; Paraense and Deslandes, 1958b) . Thus, a reliable diagnosis must be based on the anatomical characters associated, of coinse, with those of the shell. A. albicans may be readily distinguished from A. glabratus by the absence of renal ridge, or of the pigmented line that precedes it in young specimens, and of the vaginal pouch (Paraense and Deslandes, 1955a, 1959) ; from A. tenagophilus (formerly called A. nigricans by us), A. peregrinus, A. andecolus and A. prorius, by the absence of tlie vaginal pouch (Paraense and Deslandes, 1955b, 1957, 1958b, c) ; and from A. stramineus (^ centimetralis) by the absence of vaginal corrugation (Paraense and Deslandes, 1955c). Despite the great similarity of its shell, when lamellate, to that of A. janeirensis, there are remarkable anatomical differences bet^\'een the two species (for comparison, see Paraense and Des- landes, 1956) . The penial complex, the vagina and the sperma- theca of A. janeirensis are very long, the penial complex being about half as long as the whole female duct (oviduct, nidamental gland, uterus and vagina together) ; moreover, the penis sheath is from 4.7 to 7.6 times as long as the prepuce. In A. albicans, the penial complex, the vagina and the spermatheca are relatively very short, the penial complex being from 14 to 1/7 (about 1/^.5) as long as the female duct and, the penis sheath, from a little longer to about 4 times as long as the prepuce. Of the Australorbis species so far studied by us, the most closely related to A. albicans, from the anatomical standpoint, is A. philippianus (see Paraense and Deslandes, 1958a) . The latter April, 1962 nautilus 161 also has a small penial complex, the length ot which is about 1/^ that of the whole female duct (range from 1/2.5 to 1/7) . The two species may be distinguished by the characters of the penial complex and the prostate. The penis sheath is from a little longer to about 4 times as long as the prepuce in albicans; the two or- gans are about the same length in philippianiis, the ratio between the former and the latter varying from 0.9 to 1.5. And the number of prostate diverticula is much smaller in philippianiis: from 0 to about 6, as against 8 to 16 in the present sample of albicans. Acknowledgement: We are indebted to the distinguished Cu- ban naturalists Miguel Jaume and Manuel Barro, for their help- ful assistance to the senior author during his work in Cuba. Summary A description of the planorbid species Australorbis albicans (Pfeiffer, 1839) is presented. The following of its characters are considered as having diagnostic significance: Shell up to about 7 mm. in diameter and 2.5 mm. in height, usually with 6 apertural lamellae in the adult; whorls about 814, rapidly widening, bluntly carinate underneath. Absence of renal ridge. Ovotestis diverticula simple or, less frequently, bifurcate. Seminal vesicle with poorly developed diverticula. Prostate di- verticula mainly bifid or trifurcate, less frequently unbranched or arborescent, and arranged in a single row. Penis sheath from a little longer to about 4 times as long as the prepuce. Well de- veloped pouch of oviduct. Vagina tubular and smooth-walled, without pouch or corrugation. References Clessin, S., 1884. Die Familie der Limnaeiden enthaltend die Genera Planorbis, Limnaeus, Physa und Amphipeplea. In MARTINI k CHEMNITZ: Systematisches Conchylien- Cabinet, v. 17. Bauer & Raspe, Niirnberg. Paraense, W. L., 1957. Proc. Malac. Soc. London, 32 (4): 175-179. . 1961. Shell versus anatomy in planorbid systematics. I. Australorbis glabratiis. Rev. Brasil Biol., in the press. Paraense, W. L. and Deslandes, N., 1955a. Mem. Inst. Oswaldo Cruz, 53(1) :87-103. . 1955b. Mem. Inst. Osioaldo Cruz, 53(1) :121-134. . 1955c. Rev. Brasil. Biol, 15(3) :293-307. . 1956. Rev. Brasil Biol., 16(1) :81-102. . 1957. Rev. Brasil. Biol., 17 (2) : 235-243. . 1958a. Rev. Brasil. Biol., 18(2) : 209-2 17. . 1958b. Jour. Conchyliol., 98 (3) : 152-162. . 1958c. Rev. Brasil Biol., 18 (4):367-373. . 1959. Am. J. Trop. Med. & Hyg., 8 (4) : 456-472. Pfeiffer, L., 1839. Arch. f. Naturgesch., I. Zool., 5 (1) :346-358. 162 NAUTILUS Vol. 75(4) X-RAY DIFFRACTION EXAMINATION OF TWO FORMS OF OLIVA SPICATA By jerry DONOHUE and KENNETH HARDCASTLE Department of Chemistry, University of Southern CaUfornia Burch (1959) has discussed a problem concerned with identity of two forms [Cf. plate 17] of Oliva spicata (Roding, 1798) from La Paz, Baja California, which were brought to his attention by Mr. Naylor of San Diego, who stated that one form was rejected by Indian artisans on the basis that they shatter while being worked, the other form being acceptable in making various arti- facts. Although at first glance both lots appeared identical, addi- tional study revealed differences which may be summarized as follows: Used shells: Discarded shells: Base of columella Base of columella white or pink, light purple, more obese, more slender, lower spire. higher spire. For convenience, Burch temporarily identified the acceptable shells as Oliva spicata var. venulata, the discarded ones as var. ustulata, and concluded that, since the two forms were easily separable, the lumping of all these variations under one name was odd. O. venulata (Lamarck, 1811) and O. ustulata (La- marck, 1811) are usually included in the synonomy of O. spicata, e.g., by Johnson (1915) and Keen (1958). In the hope of throwing additional light on this question, we have examined, by the method of x-ray diffraction, samples taken from both forms. These samples were taken from broken frag- ments, and the locations from which the samples were taken is indicated in Fig. 1, which presents an equatorial cross section of a characteristic shell. Shells from both lots showed the structure shown in Fig. 1, i.e., a translucent outer layer which encloses the pigment, a somewhat thicker, white, inner layer which also en- closes pigment that, however, is not visible because this layer is thicker, and finally, a white, opaque, middle layer which con- tains no pigment. The outer and inner layers coalesce at the outer lip. Samples taken from the outer and middle layers of both forms showed almost the same x-ray powder diffraction patterns. All April, 1962 NAUTILUS 163 Translucent outer layer Opaque middle layer o I cm Fig. 1. Equatorial cross section of a characteristic specimen, showing the region from which the samples were selected. The dark areas represent the pigmentation, which was avoided in taking the samples for diffraction analysis. their major and minor features exactly match the pattern re- ported by Swanson, Fuyat, and Ugrinic (1954) for the aragonite polymorph of calcium carbonate. An important difference occurs, however, in the case of both kinds of samples from the form acceptable to the Indians in that faint additional lines character- 164 NAUTILUS Vol. 75(4) istic of the powder pattern of the calcite polymorph of calcium carbonate (Swanson and Fuyat, 1953) may also be seen. We estimate that about 5% of calcite occurs in the outer layer, and somewhat more than half that much in the middle layers, of the utilized form. This calcite content is significantly different from that found in the samples from the form discarded by the artisans where none at all could be detected in the middle layer and only a trace in the outer layer. It would thus appear that, in addition to the differences in shape and color between the two forms, there is also a difference in chemical constitution. There does not seem to be any a priori explanation as to why this difference should result in the differ- ence in physical character noted by the artisans. Although this may or may not be relevant, calcite is considerably softer than aragonite (hardness 3, as compared to 4, Mohs scale) , but pos- sibly the shattering property may be the result of some other effect, e.g., differences in the orientation of the aystallites in the shell. The question of which are the appropriate names to assign to these forms is discussed by Burch and Burch (1962) . Experimental Details. The x-ray diffraction patterns were re- corded photographically by the standard techniques in a Norelco powder camera, with CuKa radiation, filtered through nickel foil. All lines out to spacings of d > 1.15 A were measured. Rel- ative intensities were estimated visually. The 38 lines in this region reported for aragonite were all observed at the expected spacings and with the correct relative intensities for the four different types of samples. The calcite lines observed in the case of the samples from the "accept" form, all with very faint in- tensity, were those at d = 3.86 A and 3.035 A. These are two of the strongest lines reported by Swanson and Fuyat for calcite. All the other strong calcite lines listed by them are coincident with lines due to aragonite and were not observed. The only calcite line observed in the case of the samples from the outer layer of the "reject" form was the one at spacing 3.035 A, which is by far the strongest line of that pattern; the next most intense lines were too weak to be observed. The calcite content was estimated by comparison of the intensities of the 3.035 A line of calcite with the 2.871 A line of aragonite. NAUTILUS 75(4) PLATE 17 Upper and lower, Icli ligs.. Iiolotxpc ol Ulii'a rejecla Burch .^- Burch. Upper aiul lower, right figs., Oliva I'onilaia Lamarck. NAUTILUS 75(4) PLATE 18 Maxwell Smith, 1888-1961 April, 1962 nautilus 165 Fig. 1 was prepared by Mrs. Maryellin Reinecke. We wish to thank Mr. John Q. Burch for bringing this problem to our notice and for furnishing the specimens of both forms. References Burch, J. Q. 1959. Minutes Conch. Club So. Cal. 184:20. Burch, J. Q. and Burch, R. L. 1962. [See next paper]. Johnson, C. W. 1915. Nautilus 2