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Zz 77) ah 2 NOILALILSNI_NVINOSHLINS S3INVYEIT LIBRARIES SMITHSONIAN INSTITUTION NOILALILSNI_ NVINOSHLINS.S3 a w & wu yy, 2 tu Z ul = = ~ = 4 a = « fF =a foes pe Ss = a _< a < r= < c .< Gl rs) 2 = a. = oO = = zy S a = 3 2 a BRARIES SMITHSONIAN INSTITUTION NOILNLILSNI sgiuvugi INS So = S c 5 = = = - o — wo OD £ =: > = >: > > > (| “Ey 2 = 2 = Gs Bi . = 7) = wn es n s NOILALILSNI NVINOSHLINS S31YVYSIT LIBRARIES, SMITHSONIAN INSTITUTION $3 an a and aie Ww = ao hy € THE PELIGerR A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California Volume 14 July 1, 1971 to April 1, 1972 Page II THE VELIGER Foreword to Volume 14 THE END OF A YEAR is a Suitable time to reflect on the experiences and events of the past twelve months. For the Veliger, this period has been perhaps especially eventful. The goal of the California Malacozoological Society has been, always, to publish a journal of high quality and to give it the widest possible distribution by keeping its cost hopefully within reach of all those interested in malacology and conchology. Because of the ever increasing costs of printing and postage, it has been necessary, from time to time, to readjust the charges made for the journal. Every time the rates had to be increased, this was done with the greatest reluctance and only the absolute minimum increase was made. When the financial situation of the Veliger was reviewed, it was found imperative to make another of these undesired increases. How- ever, the timing of the “Freeze” and the uncertainties of “Phase Two” prevented the putting the increase into effect. It was decided to send out an appeal to the membership with the notices of renewals. We have been very gratified by the response to this appeal. It is an encour- aging sign and we will continue our efforts in producing an ever better journal. This is also an excellent opportunity to express our appreciation to our many friends who, in one way or another, continue encouraging us in our efforts. Special mention should be made of Mrs. Jean M. Cate, who, as Manager, devotes countless hours to the various tasks connected with the bookkeeping; she also contributes many hours to the exacting task of reading proofs. We are also grateful to the various fine crafts- men (and -women) at the Printing Department who, through their skills, help maintain a high technical standard for the publication. It is impossible to mention each one of these workers, but we must mention the special care given to our halftone reproductions by the photographer, Mr. Leo Feld. Mr. John Schoen, foreman of the pressroom, not only has given freely of his advice but, in a particular emergency, also spent many hours of hard work to help us out. Mrs. Emily Reid, staff artist in the Department of Zoology also continued to give much of her time and talent to help us toward our goal of excellence. However, there are quite a few persons who quietly are doing much either to encourage your editor or to assist the journal in various ways. It is probably unnecessary to stress that to all these individuals, named and unnamed, we are very grateful. Your Editor. Vol. 14; No. 4 Vol. 14; No. 4 TABLE or CONTENTS Additional data on Flabellina telja (Gastropoda: Opistho- branchia ) ANTONIO J. FERREIRA & HANS BERTSCH essen 414 A Discussion of the systematics, reproductive biology, and zoogeography of Polycerella emertoni and related species (Gastropoda : Nudibranchia) Davin R. FRANZ & KERRY B. CLARK reiscsssssnsssntineen 265 A mesofaunal collecting kit for SCUBA work in frigid waters SIMERMAN BLEAK NEY. sictisctaciatamcniutmnnashscnmienris 212 A new Caecum from the Sea of Cortez (Prosobranchia : Caecidae) CARRE DM ELON G peta ete cct aaa cs Senden eli cael taseehtaat 291 A new Engina in Florida IVIRBEMTEE NCROW Octet thomsen sie al ace 30 A new species of Chelidonura from Bahia San Carlos, Gulf of California, with a synonymy in the family Aglajidae TERRENCE GOSLINER & GARY WILLIAMS cence 424 A note on gametogenesis in the oyster drills, Urosalpinx cinerea (Say) and Eupleura caudata (Say) Joun J. Manzi, A. CarasresE & D. M. Rawiins 271 A Recent record of a rock-boring clam, Zirfaea crispata (Linnaeus) from Newfoundland T35 AS INUSUUON GT. gk IRS Serer an a en a en 31 A revised classification of the family Turridae, with the proposal of new subfamilies, genera, and subgenera from the Eastern Pacific Sates SB MIGIERIAIN I pita enor ome ele hee aaa an 114 A rheotaxic study of three gastropod species PIVETONOAS IVI ID) CET eek et oe Mabe una ie ih 73 A taxonomic note PAWN [i Aer Nie lest bine eared ds dealin ou 440 Cell renewal systems in the gut of the oyster, Crassostrea gigas (Mollusca : Bivalvia) IW OCORS OATS CS (Cu: NUD tee eee eet eee at oe 202 Competitive co-existence: maintenance of interacting as- sociations of the sea mussels Mytilus edulis and Mytilus californianus PRINOBINGEVARGER) (rsa mec ttre Me Mon Shaler a Ae 387 Contribution to the taxonomy of the Muricidae (Gastro- poda : Prosobranchia ) MATTER! © CERNOHORSK YA aeeen enee e 187 Cypraea: a list of species. IT. JERR va DONOELUE yore cctn te tonaenorieeene Ahn os 64 Description of Doto (Doto) fragilis nipponensis subspec. nov. from Sagami Bay, Japan (Nudibranchia : Dendronotoidea : Dotoidae) SUK TAR OF BABA Were i renee um ean ANN aa ta 153 THE VELIGER Page III Distribution and zoogeography of fourteen species of nudi- branchs of northern New England and Nova Scotia INANTAUITONO) BANGER OUR VE Rares sin nrehcmceniansaan 137 Duration of useful survival of the isolated radula protrac- tor of the gastropod Busycon canaliculatum ROBERT EAI Tope te nates cet lar this tine eatin da 373 Effect of scorpion venom on the ciliary activity of fresh water mussel D.C. Raju, R. V. KrisHNAMoorTHY &A.S. Reppi 192 Effect of turbidity on the rate of filtration and growth of the slipper limpet, Crepidula fornicata Lamarck JOHN KENNETH JOHNSON vmstat 315 Embryology and larval development of Coryphella tri- lineata O’Donoghue, 1921 (Gastropoda : Nudi- branchia ) CeEcItia BRIDGES & JAMES A. BLAKE wesssssniettine 293 Embryonic development and post-hatching survival of the sepiolid squid Euprymna scolopes under laboratory conditions Joun M. Arnotp, Cart T. SINGLEY & LOIS HOM WILLIAMS “ARNOLD 0 eee ate 361 Eubranchus misakiensis Baba, 1960 (Nudibranchia : Eoli- dacea) in San Francisco Bay DAV IDIVVSIBEHIRENS) eee castes cennciet ten anaes 214 Feeding and associated morphology in Sanguinolaria nuttalli (Bivalvia : Tellinacea) HROSS PEL ROH TOM reer reteset renner tetra 298 Field identification of crab predation on Shaskyus festivus and Ocenebra poulsoni (Prosobranchia : Muricidae) INTC KR OTETERING EXAM eae eet ee ieee ees 204 Homing behaviour and population regulation in the lim- pet Acmaea (Collisella) digitalis PAUL OAH BREEING ete tih ne ila tte oll BEREAN eas ntaet 177 Host texture preference of an ectoparasitic opisthobranch, Odostomia columbiana Dall & Bartsch, 1909 TGS TINH CHAIR este ears soe Neca Ind reste 54 Ingestion of bivalve molluscan larvae by the polychaete annelid Polydora ligni Wixpor P. BREESE & FE DUANE PHIBBS oerccssssecsenes 274 Malacological applications of scanning electron micro- scopy. — II. Radular structure and functioning INTE SODE Mayers Witetten se tan attention eure: 327 Natural history and occurrence of opisthobranch gastro- pods from the open coast of San Mateo County, California Hans BertscH, TERRENCE GOSLINER, ROBERT WHARTON & GARY WILLIAMS ovsccssssnessussussenntssiee 302 New Pacific Northwest Neptuneas (Mollusca : Gastropo- da : Neptuneidae) ADEY NGG ISMIRE, G20 ected: UIE crcl 33 New record of a color variation in Spurilla oliviae GARY @.) WIEDIAMSS 9 Sec ie ee ieee naan 215 Page IV New species of tropical Eastern Pacific Turridae JAMES H. McLEAN & Roy POORMAN oerccesssssnsssstsin 89 Note on an unusual Pacific coast cephalopod UTETAVING Gen MINT Elen teneenectare este nec ees tore treme 135 Note on feeding habits of the desert snails Sphincterochila boissieri Charpentier and Trochoidea (Xerocrassa) seetzeni Charpentier Y. YOM-Tov & MARGALITH GALUN ccsmssscsesnensninens 86 Notes on some California Mollusca: Geographical, eco- logical, and chronological distribution ROBERT) ROMPATNEADGE jen nti ee ee eee eee: 411 Observations on the food and feeding of some vermivorous Conus on the Great Barrier Reef IRL ENE WEARS EE) Wanner ieee ere cee eniarle enon 45 Observations on the sea hare Aplysia parvula (Gastropo- da : Opisthobranchia) from the Gulf of Califor- nia ANTES RSMCAN GES ee creer at ern ate teens 60 On the identity of Murex phyllopterus Lamarck, 1822, a tropical Western Atlantic species (Gastropoda : Prosobranchia ) WiiuiAM K. Emerson & WILLIAM E. OLp, Jr.._...... 350 On the reproductive biology of Mitra idae (Gastropoda : Mitridae) James R. Cuess « Ricuarp J. ROSENTHAL ........... 172 Pacific species of Nesiodostomia Pilsbry, 1918, and Pupo- syrnola Cossmann, 1921 (Gastropoda : Pyrami- dellacea) JAMES ECE CORGAIN tibet erecta ree ais ec Bae 355 Predation of Marisa cornuarietis on Oncomelania formos- ana eggs under laboratory conditions Lots Wonc Cut, LinpsAy R. WINKLER & RSW COLVIN) a pee meee estan at erie ante nna 184 Range extension for Columbella sonsonatensis MOrcH UD Joy vel [vals Gs or Nasser en Nee nates a Ns ett a ete 321 Range extensions of some Northeast Pacific nudibranchs (Mollusca : Gastropoda : Opisthobranchia) to Washington and British Columbia, with notes on their biology GorponpAs ROBIETIARD seer ree o een eer eone ate 162 Reproduction of Scrobicularia plana da Costa (Pelecy- poda : Semelidae) in North Wales IROGER TN SHIUGEDES iy fates eer meter ne mentees 77 Reproductive system and gonadal activities in Lamelli- dens marginalis (Simpson 1900) CuHiTrRivA GHOSH & K. C, GHOSE veeesssseatissisieens 283 Scanning electron microscopy of planktonic larval marine gastropod shells Rospert RoBpertson Soviet contributions to Malacology KENNETH J. Boss & Morris K. JACOBSON _ .......000 437 THE VELIGER Vol. 14; No. 4 Structure and function of the alimentary tract of Batillaria zonalis and Cerithidea cailfornica, style-bearing mesogastropods ANDREW Io. DRISGOLT) 0 Ue ceo ee 375 Studies on the food of nudibranchs JAMES W. MCBETH” foe Seca. cccc eee 158 Ten new species of tropical Eastern Pacific Turridae DoNnaALp R:'SHASKY eee oe 67 Thais emarginata (Deshayes) : description of the veliger and egg capsule RENEE LEBOEUF! ((2...he coher ee 205 The benthic Mollusca, Plicifusus, in California (Gastro- poda : Mollusca) RoperT R. TALMADGE. (ne ee WA? The biology and a redescription of the opisthobranch mol- lusk Hermaea cruciata Gould from Chesapeake Bay (Sacoglossa : Hermaeidae) Rosarre M. VOGEL unites eee 155 The ecology of the nest-building bivalve Musculus lateralis commensal with the ascidian Molgula occidentalis Grrarp A. BERTRAND © .:.0.¢.ccosslunoin to eee oes) The effect of storms as a density dependent mortality fac- tor on populations of sea mussels J. R. E. Harcer & D. E. LANDENBERGER .......c00 195 The escape reaction of Donacilla angusta Reeve (Mollus- ca : Bivalvia) in the presence of a naticid predator HELENE M. LAWS & D. FLAWS oesescsesnssssnsnesseeeseneen 289 The feeding and reproductive behaviour of the sacoglossan gastropod Olea hansineensis Agersborg, 1923 SANDRA CRANE | ald.ccstenan cnn lean on The fine structure of the nervous system of Bithynia tenta- culata (Prosobranchia) in relation to possible neu- rosecretory activity ELIZABETH BYANDREWS) pete tres ent eee 13 The form and functioning of the pallial organs in the opisthobranch Akera bullata, with a discussion on the nature of the gill in Notaspidea and other tecti- branchs J. E. MortTON® rae uh cence ane 337 The Pectinidae (Mollusca : Bivalvia) of Eniwetok Atoll, Marshall Islands Tuomas R: WALLER | ui. fe eaee peer at eee 221 The reinstatement of Hypselodoris agassizi (Bergh, 1894) (Mollusca : Opisthobranchia ) Gave G: SPHON ..2.ccc ee eer 214 The tidal migration of Donax variabilis Say (Mollusca : Bivalvia ) WiIcLiAM Cin ANY) Miata nserrneecetnet eaters 82 Three new species of eolid nudibranchs from the west coast of North America (Gastropoda : Opistho- branchia ) RIGHARD!A: ROLLER \(:.n.0e eae teen nen eee 416 Vol. 14; No. 4 Trace metal levels in intertidal mollusks of California DAV AD PLE GRATUAMS ites ca ete te ce eteceeseastetentet indents 365 Variation and relative “niche” size in the sea mussel Myt7- lus edulis in association with Mytilus californianus IPRINOBIN@IVARGE RS pateece eter tect ri nneekcrate cera: 275 Veliger development in Dendronotus frondosus (Ascanius, 1774 (Gastropoda : Nudibranchia) TRESS TET GSTS TANS) alpen esate ec tetestctiec 166 AUTHOR INDEX PANIDRENV Se LIZABE TED Bs cccrsccs cc aceite terrarrisetsceneesstinncecccsanse 13 ARNOLD, JoHN M., Cart T. SINGLEY & TEOIS MD WILETAMS-ARNOED) 19" SARE ‘ X ‘- ’ \ . Figure 32 Figure 33 Figure 34 Vol. 14; No. 1 THE VELIGER Page 9 The brown larval shell is ovate, 0.6-1.0 mm long, 0.5— 0.8 mm wide and with 4.7—5.0 whorls. Scheltema’s larvae average larger than mine, and so also do the protoconchs both of us have studied. The early postembryonic sculp- ture consists of major and minor spiral ridges crossed by axial ridges that become less prominent and more irregu- lar towards the lower suture. This sculpture gradually changes so that on the last two larval shell whorls there is a different pattern of reticulation, the interspaces being triangular on the shoulder and (on the last whorl only) quadrangular at the periphery and on the base (Plate 7, Figures 25-26). Two series of ridges cross each whorl obliquely and are nearly at right angles to each other. At each intersection there are projecting nodes, and two or three spiral ridges interconnect the second and third or fourth subsutural series of nodes. On some specimens there are traces of one additional spiral ridge lower down. Per whorl, there are 27—28 nodes per spiral series (Plate 8, Figure 28). Each triangular interspace is minutely spirally striate, the major striae being 0.5—2.0 microns apart (Plate 7, Figure 27); on the base, the striae no longer are spiral; instead, they nearly parallel the steeply ascending ridges. The embryonic shell, 0.13 to 0.14 mm in diameter, is clearly demarcated from the postembryonic shell by a growth line and an abrupt sculptural change, both re- cording the stage at which the embryo hatched from the egg mass (Plate 8, Figures 28—29).* The embryonic shell surface is pitted except near the beginning of the suture and towards the growth line, where it is nearly smooth. The pits are nearly circular (commonly fused) and have radiating grooves; the pits increase in size away from the smooth areas; the larger pits are 3 to 4 microns in di- amater (Plate 8, Figures 30-37). ‘These embryonic shell pits are reminiscent of those of Litzopa, but Pedicularia has larger pits and a less granulated surface. The outer lip is sinusigerous, with the left major con- cavity divided by a minor projection (Plate 9, Figure 32). Two distinct shell layers show on the outer lip and the inner of these extends slightly beyond the outer. Only the inner layer extends onto the parietal area. Its surface is covered with lamellar, quasi-hexagonal, projecting crystals 4 Hape (1955, figs. 4 and 6) illustrates two newly hatched em- bryonic shells of Pedicularia stylasteris Hedley, 1903, that are up to 0.16 mm in diameter; no sculpture is shown. HaBE believed he had observed ovoviviparity, but I think it more likely that he saw in the mantle cavity brooded egg capsules containing em- bryos that were about to hatch and become planktotrophic (see also Dati, 1889: 238 - 239, and Scui_pER « ScuiLpErR, 1944: 30). I have observed masses of similar embryonic shells in the dried bodies of both P. sicula and P. californica Newcomb, 1864. 1 to 7 microns in diameter that dip at an acute angle inwards from the outer edge of the aperture (Plate 9, Figures 33-34). This crystalline surface extends deep into the aperture. The living larva has four long velar lobes like the “Radius [= Neosimnia] or Cyphoma... related to Simnia”’ from near Bermuda studied by LEBour (1945: 474-475, fig. 21). Scheltema identified her veliger as Pedicularia but I think this doubtful because Lebour’s figure does not show subsutural triangles and spiral ridges. ‘Two larval European ovulids in the genus Simnia, s. l., studied by Lespour (1932) and THiriot-QulEvrREUx (1967) lack the subsutural triangles and spiral ridges of Pedicularia but otherwise are closely similar. They both have a clearly demarcated embryonic shell. Lebour noted ‘‘a granular irregular pattern all over it’’ (loc. cit., plt. 1, fig. 8), and Thiriot-Quiévreux described the surface as having a ham- mered appearance. CONCLUSIONS anp FUTURE PROSPECTS Observations of living veligers and of their shells should continue to be carried as far as possible with regular light microscopy and photography. However, the small size and intricate shell surface features of most planktonic gastro- pod larvae impose low limits on what can be seen. The SEM, with its low to high magnifications, high resolu- tion, and great depth of field overcomes these limits, and is therefore indispensable for studying and illustrating the microsculpture of shells and opercula. Even at commer- cial rates, costs per scanning electron microscope photo- graph compare favorably with costs for low magnification light photographs or publishable camera lucida line drawings. The 10 hours used for studying the specimens treated in this paper yielded 71 photographs, 34 of which are published here. SEM comparisons of larval shells with protoconchs aid specific identifications. SEM observations also reveal new systematic characters, and help to relate external shell microsculpture with internal microstructure. Unexpected features revealed in the present study include the im- mersed and tilted coiling of the embryonic shell of Smaragdia viridis, the close sculptural similarity between the larval shells of Litiopa melanostoma and Alaba in- certa, the distinctive larval shell sculpture of Janthina, and the quasi-hexagonal lamellar crystals projecting on the peritreme and in the aperture of larval Pedicularia decussata. The grossly similar embryonic shell micro- sculpture of Litiopa and Pedicularia seems attributable to similar internal shell structure — probably vertical crystalline rods that outcrop as pits and granular crests. Page 10 In his ‘‘shell apex theory,’ THorson (1950: 33-34; fig. 6) suggested that it should be possible to determine from the shape, sculpture, and size of a protoconch whether the larva had been pelagic and planktotrophic. However, he concluded that “a general rule valid for all apices cannot be given.”’ OCKELMANN (1965) extended the idea to bivalves, and has shown how, at least within fami- lies, embryonic shell sizes correlate with egg sizes, and how developmental types can be deduced from larval shells. With the aid of the SEM, I believe that similar deductions can be made from gastropod protoconchs by relating egg sizes and developmental types not with whole larval shells but with embryonic shell sizes or first whorl diameters. Small embryonic shells with small first whorl diameters can be expected to grow from small, yolk-poor eggs with pelagic, planktotrophic development, while larval shells with large first whorl diameters and without demarcated embryonic shells should grow from large, yolk-rich eggs with lecithotrophic (direct) development. On nearly all planktonic larval gastropod shells that I have studied with the SEM, the embryonic shell is readily distinguishable from the postembryonic larval shell. There usually is a growth line recording the stage when the larva hatched from the egg mass or capsule, and in many cases the embryonic and postembryonic sculptures differ (as, for example, in Pedicularia decus- sata). With the SEM, embryonic shell sizes and first whorl diameters can now for the first time be observed and measured accurately. Comparisons need to be made with uncleaved egg diameters. Judging by the clarity with which the SEM revealed ultrastructural features in the muscle scar on the internal surface of larval Litiopa opercula, the instrument should aid the study of how muscles are attached and detached to opercula and shells (columellas) while they grow. Light microscopy and transmission electron microscopy (includ- ing replica techniques) were used by HuBENpIck (1957) before the SEM became available. Freeze drying and other techniques for preparing soft tissues and ciliated surfaces for the SEM (BoypE & Woon, 1969; HoLsorow et al., 1969; Horripce « Tamm, 1969; MARSZALEK & SMALL, 1969) have not yet been applied to veligers, but should be useful for studying the external morphology and ciliation of the velum, mouth region, and foot. SUMMARY Methods of using the scanning electron microscope (SEM) for studying planktonic larval gastropod shells and oper- cula are described, and examples are given of the kinds of THE VELIGER Vol. 14; No. 1 results that can be achieved. The examples were chosen from among some pelagic veligers collected from plankton near Bermuda. A larva shown to be that of Smaragdia viridis (Linnaeus) has an embryonic shell that is tilted and immersed, and the larval operculum already is typi- cally neritid. The larval shells of Litiopa melanostoma Rang and Alaba incerta (Orbigny) are shown to be closely similar, affording evidence that these two cerithiacean genera are closely related. Comparisons of the larval shells of Janthina janthina (Linnaeus), an ovoviviparous (larvi- parous) species, with those of J. pallida Thompson, an oviparous (ovigerous) species, reveal few differences other than larger size of the former; both have distinctive sinu- ous axial growth lines. The larval shell sculpture of Pedt- cularia decussata Gould consists of diagonal and spiral ridges with quadrangular and triangular interspaces; on the peritreme and in the aperture there are numerous, quasi-hexagonal lamellar crystals that project and dip inward. Although widely unrelated, Litiopa and Pedi- cularia have grossly similar embryonic shell microsculp- ture consisting of pits and granulated crests; these are at- tributed to vertically outcropping, rod-shaped crystals. Some micromorphologic larval shell features observable with the SEM record such early life history stages as the hatching of embryos. In future studies, the SEM should be helpful in deducing from a protoconch whether the larva was pelagic and planktotrophic. With dehydration techniques, the external body morphology and ciliation of veligers could be studied with the SEM. ADDENDUM In a paper received after this was submitted for publica- tion, FRETTER & PILKINGTON (1971) have reported use of the SEM to study larval shells of various British proso- branch gastropods. They paid particular attention to en- dogenous rhythms in shell growth (when larvae are cul- tured under constant temperature and light conditions, shell growth is intermittent). According to FRETTER & PILKINGTON, none of the pelagic larval shells they studied are calcified until metamorphosis—in striking contrast to those I have studied. They believe that prior to calcifica- tion, larval whorl diameters can increase by the flexible and fibrous organic matrix being stretched by enlarge- ment of the viscera. Using different terminology from that defined here, FRETTER & PILKINGTON record interspecific differences in larval shell microsculpture, and attribute differences in the patterns made by external convexities to differences in the genetically determined placement of calcareous concretions in the otherwise uncalcified or- ganic matrices. 7 , Vol. 14; No. 1 THE VELIGER Page 11 Literature Cited Assott, RoBert TUCKER 1958. The marine mollusks of Grand Cayman Island, British West Indies. Monogr. Acad. Nat. Sci. Philadelphia 11: i-viit1- 138; 11 maps; 7 text figs.; 5 plts. (31 December 1958) ApAMSs, ARTHUR 1862. On the animal and affinities of the genus Alaba, with a review of the known species, and descriptions of some new species. Ann. Mag. Nat. Hist., ser. 3, 10: 293 - 299 ALBANY, RicHarp L. 1940. A new character of the early stages of the mollusc Janthina exigua. The Nautilus 54 (2): 73; plt. 2, fig. 4 Bayer, FREDERICK MERKLE 1963. Observations on pelagic mollusks associated with the siphonophores Velella and Physalia. Bull. Mar. Sci. Gulf and Caribb. 13: 454 - 466; 7 figs. BoypbE, ALAN & C. Woop 1969. Preparation of animal tissues for surface-scanning elect- ron microscopy. Journ. Microsc. 90 (3): 221-249; 18 figs.; 3 tables Craven, ALFRED-E. 1877. | Monographie du genre Sinusigera, d’Orb. Soc. Malacol. Belgique 12: 105 - 127; plts. 2-4 Dati, WiLL1am HEALEY 1889. Reports on the results of dredging, . . . in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U. S. Coast Survey Steamer “Blake”, . .. Report on the Mollusca, pt. 2, Gastropoda and Scaphopoda. Bull. Mus. Comp. Zool., Harvard Coll. 18: 1 - 492; plts. 10-40 DAUTZENBERG, PHILIPPE 1889. Contribution a la faune malacologique des Iles Acores. Révision des mollusques marins ... Rés. Camp. Sci. Albert 1e* de Monaco, Fasc. 1, 112 pp.; 4 plts. (15 October 1889) DautzENBERG, PHILIPPE & HENRI FISCHER 1896. Dragages effectués par l’Hirondelle et par la Princesse Alice, 1888-1895. Campagnes scientifiques de s. a. le Prince Albert 1" de Monaco. Mem. Soc. Zool. France 9: 395 to 498; plts. 15 - 22 FRETTER, VERA & MarcareT C. PILKINGTON 1971. The larval shell of some prosobranch gastropods. Journ. Mar. Biol. Assoc. U. K., ser. 2, 51 (1): 49-62; 3 text Mém. figs.; 2 plts. (February 1971) GraHaM, ALASTAIR 1954. | Some observations on the reproductive tract of Ianthina janthina (L.). Proc. Malacol. Soc. London 31 (1): 1-6; 3 figs. Hasse, TADASHIGE 1955. Notes on Pedicularia (Pediculariona) stylasteris Hedley var. Venus, Japan. Journ. Malacol. 18 (3): 157 - 160; 6 figs. Hansen, H. J. 1968. A technique for removing gold from plated calcareous microfossils. Micropaleont. 14 (4): 499 - 500 HEDLEY, CHARLES 1903. Scientific results of the trawling expedition of H. M. C. S. “Thetis” off the coast of New South Wales in February and March 1898. Mollusca, Part II. Scaphopoda and Gastropoda. Mem. Austral. Mus. 4 (6): 327 - 402; text figs. 61 - 113; plts. 36 - 38 (8 October 1903) Ho.sorow, P.L., M. S. Laverack «& V. C. BARBER 1969. Cilia and other surface structures of the trochophore of Harmothoé imbricata (Polychaeta) . Zeitschr. Zellforsch. 98: 246 - 261; 15 figs. Horripce, G. A. « S. L. Tamu 1969. Critical point drying for scanning electron microscopic study of ciliary motion. Science 163 (3869): 817-818; 2 figs. and cover photograph (21 February 1969) HuseEnpick, BENGT 1957. On the molluscan adhesive epithelium. Zool., ser. 2, 11 (3): 31-36; 1 text fig.; 3 plts. KimotTo, Sizuo & J. C. Russ 1969. The characteristics and applications of the scanning elec- tron microscope. Amer. Scient. 57 (1): 112-133; 28 figs. Kose._t, WILHELM 1906-1908. Iconographie der schalentragenden europdischen Meeresconchylien. | Wiesbaden (Kreidel’s Verlag), 4: 172 pp.; plts. 99 - 126 LaursEN, Dan 1953. The genus Janthina; a monograph. Dana Report 6 (38): 1-40; 41 text figs.; plt. 1 (20 November 1953) LeExsour, Marie V. 1932. The larval stages of Simnia patula. | Journ. Mar. Biol. Assoc. U. K., ser. 2, 18 (1): 107-115; 1 text fig.; 2 plts. Arkiv for 1945. The eggs and larvae of some prosobranchs from Ber- muda. Proc. Zool. Soc. London 114 (4): 462 - 489; 43 figs. Lewis, Epwin R., Tuomas E. EvERHART & YEHOSHUA Y. ZEEVI 1969. Studying neural organization in Aplysia with the scan- ning electron microscope. Science 165 (3898): 1140 to 1143; 5 figs. (12 September 1969) MacponaLp, JoHN DENIS 1858. On the probable metamorphosis of Pedicularia and other forms; affording presumptive evidence that the pelagic Gasteropoda, so called, are not adult forms, but, as it were, the larvae of well-known genera, and perhaps confined to species living in deep water. Trans. Linn. Soc. London 22: 241 to 243; plt. 42 MarsZALEk, Dona.p S. & EUGENE B. SMALL 1969. Preparation of soft biological materials for scanning electron microscopy. In: Scanning Electron Microscopy /1969, Proc. Second Ann. S. E. M. Symposium, pp. 231 - 239; 21 figs. Chicago, Illinois (ITT Research Inst.) (April 1969) OckELMANN, Kurt W. 1965. | Developmental types in marine bivalves and their dis- tribution along the Atlantic coast of Europe. Proc. First Europ. Malacol. Congress (1962), pp. 25 - 35; 5 figs. PALMER, KATHERINE VAN WINKLE 1942. Notes on the name Litiopa melanostoma Rang and dis- tribution of the species. The Nautilus 55 (4): 128 - 130 Page 12 THE VELIGER Vol. 14; No. 1 PeILe, ALFRED JAMES 1926. The Mollusca of Bermuda. London 17 (2-3): 71-98; 4 text figs. RéEcLuz, Constant A. 1852. | Recensement des Nérites (sous-genre Neéritine) de la France continentale. Journ. de Conchyliol. 3: 282 - 298 RosErTSON, ROBERT 1970. Review of the predators and parasites of stony corals, with special reference to symbiotic prosobranch gastropods. Pacific Sci. 24 (1): 43 - 54 Runuam, Norman W.« P. R. THorRNTON 1967. | Mechanical wear of the gastropod radula: a scanning electron microscope study. Journ. Zool. (London) 153 (4): 445 - 452; 1 text fig.; plts. 1-6 RussEL_, HENry DRUMMOND 1941. The Recent mollusks of the family Neritidae of the western Atlantic. Bull. Mus. Comp. Zool. Harvard College 88 (4): 347-404; 4 text figs.; 7 plts. (August 1941) ScHEtLTEmA, Rupotr S. In press. Larval dispersal as a means of genetic exchange be- tween geographically separated populations of shallow-water benthic marine gastropods. Biol. Bull. (Woods Hole) Scuitper, Franz ALFRED 1931. Revision of the subfamily Pediculariinae. Journ. Conchol. 19 (6): 165 - 169; plt. 6 (December 1931) SCHILDER, FRANZ ALFRED & Maria SCHILDER 1944. Westpazifische Cypraeacea von den Forschungsreisen des Prof. Dr. Sixten Bock. Ark. for Zool. 36A (2): 1-32 (pp. 11-32 authored by FE A. ScuiLper only) (11 Sept. 1944) SimrotH, HEInricH 1895. Die Gastropoden [mit Ausschlu8 der Heteropoden und Pteropoden] der Plankton-Expedition. Ergebn. Plankton- Exped. d. Humboldt-Stiftung. vol. II. FE d. 206 pp.; 17 text figs.; plts. 1 - 22 Proc. Malacol. Soc. Sotem, G. ALAN 1970. | Malacological applications of scanning electron micro- scopy. I. Introduction and shell surface features. The Veliger 12 (4): 394-400; plts. 58-60 (1 April 1970) TurrioT-QuIEVREUX, CATHERINE 1967. Observations sur le développement larvaire et postlar- vaire de Simnia spelta Linné (Gastéropode Cypraeidae) . Vie et Milieu, ser. A: Biol. marine 18 (1-A): 143 - 151; 3 pits. (October 1967) 1970 [“1969”). Caractéristiques morphologiques des véligéres planctoniques des gastéropodes de la région de Banyuls-sur- Mer. Vie et Milieu, ser. B: Océanogr. 20 (2-B): 333 to 366; 1 text fig.; 5 plts. (January 1970) THorson, GUNNAR 1950. Reproductive and larval ecology of marine bottom in- vertebrates. Biol. Rev. 25 (1): 1-45; 6 figs. (January 1950) Turner, RutH Drxon & ARTHUR CHRISTIAN JOHNSON 1969. | Some problems and techniques in rearing bivalve larvae. Amer. Malacol. Union Ann. Repts. for 1969 [Bull. 36]: 9 - 13; 3 figs. (19 December 1969) WENZz, WILHELM 1940. Gastropoda. Teil I. Allgemeiner Teil/Prosobranchia. Lieferung 4 in Otto H. Schindewolf [ed.], Handbuch der Pala- ozoologie, Berlin (Borntreger), Band 6, Teil 1, pp. 721 - 960; figs. 2084 - 2787 (August 1940) Witson, Douctas P. & M. ALtison WILSON 1956. A contribution to the biology of Janthina janthina (L.). Journ. Mar. Biol. Assoc. U. K., ser. 2, 35: 291 - 305; 2 tables; 2 text figs.; plt. 1 Wisk, SHERWOOD W, Jr. 1970. | Microarchitecture and deposition of gastropod nacre. Science 167 (3924): 1486-1488; 3 figs. and cover photo- graph (13 March 1970) Vol. 14; No. 1 THE VELIGER Page 13 The Fine Structure of the Nervous System of Bithynza tentaculata (Prosobranchia) in Relation to Possible Neurosecretory Activity ELIZABETH B. ANDREWS Department of Zoology, Bedford College (University of London) Regent’s Park, London N. W. 1., England (3 Plates; 2 Text figures) INTRODUCTION IT HAS BEEN SHOWN that several types of cells occur in the nervous system of Bithynia tentaculata (Linnaeus, 1758) which differ from the majority of neurones both in cytological detail and in their reactions to those stains used to detect neurosecretion (ANDREWS, 1968). They contain variable numbers of secretory droplets, and occur in groups in all ganglia except the pedal and osphradial, as well as in the visceral loop and visceral nerves. The following description of the fine structure of the nervous system in mature snails, fixed at a time of year when they are not breeding, is primarily concerned with examining the possibility that they are neurosecretory cells. METHODS The snails were collected in October and kept in tap water at room temperature. The nervous system was dis- sected and the surrounding connective tissue removed in cold 3% glutaraldehyde in 0.1M sodium cacodylate buf- fer, pH 7.2 - 7.4. Individual ganglia and short pieces of nerves were fixed in this solution for 2 hours, followed by 30 minutes in 1% osmium tetroxide in 0.1M veronal acetate buffer. The material was embedded in Epon 812, and sections were mounted on uncoated copper grids, stained in 5% uranyl acetate (Watson, 1958), and lead citrate (REyNotps, 1963). They were examined in an AEI EM6B electron microscope. RESULTS The histological and ultrastructural features of the various types of cells found in the nervous system are summarized in Table 1, and their fine structure is illustrated diagram- matically in Figures 1 and 2. Four types of cells were identified in histological prep- arations and described fully in an earlier paper (ANDREWS, 1968): so-called “ordinary” neurones, which are not stained selectively by any of the methods used (Figure 1, a, b) ; and 3 other types (S1, S2, $3), possibly neurosec- retory, which are differentially stained. The possible neu- rosecretory cells include: one type restricted to the cereb- ral ganglia, which is distinctive in its strong affinity for phloxin (Figure 1c); a second, occurring in localized areas of all ganglia except the pedal and osphradial, and stained intensely by aldehyde fuchsin (Figures 2, a, b) ; and a third type, the “bipolar neurones” of the visceral connectives and nerves, also stained by aldehyde fuchsin (Figure 2c). A study of the fine structure of the nervous system has revealed a more complex organization than this in the following respects: (1) Secretory granules are present in the cytoplasm of “ordinary” neurones, as well as in possible neurosecretory cells, although they differ from neurosecretory granules both in size and number (Figures 1 and 2). (2) The neurosecretory areas of the cerebral ganglia contain not one( as previously thought), but two types of neurosecretory cells, the one being phloxinophil (S1, Fig- Page 14 a4 eo. Figure 1 (a) An “ordinary” neurone, containing large numbers of yellow spherules and electron-dense secretory granules. (b) An “ordinary” neurone with large numbers of yellowish- green spherules (lysosomes). Smooth endoplasmic reticulum is distended and filled with finely granular contents. The electron-dense secretory granules are accompanied by larger clear vesicles. THE VELIGER Vol. 14; No. 1 c — membrane-bounded inclusions thought to contain carotenoid pigment cv —clear vesicle gb — Golgi body ger — granular endoplasmic reticulum gly — glycogen ing — immature neurosecretory granule li — lipid ly —lysosome (= inclusion containing lipofuscin pigment) mi — mitochondrion n—nucleus nf — neurofibril nt — neurotubule r — ribosome sg — secretory granule ser — smooth endoplasmic reticulum Vol. 14; No. 1 THE VELIGER Page 15 ure Ic), the other fuchsinophil (S2, Figure 2a). This explains previously confusing anomalies in staining re- actions. (3) ‘Two types of possible neurosecretory cells, indistin- guishable by light microscopy, occur in other ganglia, and can be seen to have elementary neurosecretory gran- ules of different sizes (S2 and S3, Figures 2, a, b). (4) The “bipolar neurones” of the visceral connectives and nerves resemble mucus-secreting cells rather than neurones in their fine structure, and are probably some kind of neuroglial or connective tissue cell (S4, Figure 2c). Similar cells have been identified in electron micrographs of the neurosecretory areas of the ganglia, with the excep- tion of the cerebral, but in sections of the ganglia they have been cut in such a plane that they look like narrow unipolar cells. In the nerves they are often cut longitu- dinally, and so look spindle-shaped. Cell types $1, S2, and S3 will be referred to subsequently as NS cells, groups of them as NS areas, and neurosecre- tory material as NSM. The neurones and neuroglial cells of Bithynia contain al? variety of cytoplasmic inclusions, some of which may mimic NSM in routine histological preparations. For this reason it was important to confirm the identification of both these inclusions and NSM at the ultrastructural level. It was established that there are 3 categories of in- ; clusions which take the form of cytoplasmic droplets or es). .. 3 o? oo ea Pe granules, and their characteristics are summarized in ci 90.0: fa BS Table 1. Droplets of yellow carotenoid pigment (1) j abound in “ordinary” neurones only; the greenish-yellow lipofuscins (2) are found in all cells, and in electron micro- graphs they have the appearance of lysosomes; the colour- less droplets (3) of living cells are shown to be lipids, free in the cytoplasm. The “ordinary” neurones of Bithynia have very dense cytoplasm (Figure la, b; Plate Figures 3, 4), with granu- lar endoplasmic reticulum (ger), free ribosomes (r), and neurotubules (nt), well developed peripherally. The cent- ral region of the cytoplasm is packed with long mitochond- ria (m), and Golgi bodies (gb). They may contain relatively small areas of glycogen (gly). Most “ordinary” neurones have large numbers of drop- lets (c) containing yellow carotenoid pigment which appear in electron micrographs as areas of fine dense granules amongst a slightly less dense matrix, and sur- rounded by a unit membrane. Their sizes range from 0.2 - 1.0 pm. Larger inclusions (ly), some 1.0 - 2.0 um, have much more variable contents composed of some electron- dense bodies in a finely granular ground substance of moderate density. Rarely, they contain traces of mem- branes. They bear a striking resemblance to the lysosomes (c) An NS cell type S1. The cytoplasm is less dense than that of other neurones and neurofibrils are more conspicuous. Golgi bodies are numerous and endoplasmic reticulum and glyco- : 5 ‘ 5 gen are localized. of other cells, and are the lipofuscin spherules identified Page 16 THE VELIGER Vol. 14; No. 1 Table 1 Characteristics of cytoplasmic inclusions and secretory granules of cells in the nervous system of Bithynia tentaculata Staining “Ordinary” NS cells NS cells Mucoid cells Reaction neurones $1 $2&83 $4 Living, 1. yellow < 1pm bluish-white bluish-white unstained 2. yellow-green < 2um bluish-white 3. colourless, variable Living, 1. = = = = methylene blue 2. oF oe - Tron haematoxylin 1. - aF at pale grey 2. + 3h - Herlant 1. - pale blue, vacuolated purplish blue intense blue 2. green 3, - Azan Il. - pale blue, red clumps, red or blue, intense blue 2. yellow green vacuolated not vacuolated 3: - After oxidation: 1. - - + pale grey Chrome haematoxylin 2: + 3. - Phloxin = nm = = Aldehyde fuchsin 1. - = a + 2. + 3, - Orange G _ a = = Alcian blue il - 72, + - + + 3. - Alcian blue/alcian yellow 1. - 2. turquoise pale yellow turquoise turquoise - deep green 3, - Without oxidation: - - - - Alcian blue Aldehyde fuchsin - - - - Epon sections, Toluidine 1. greenish grey + + pale grey - dark blue blue (Jeon, 1965) 2. dark green 3. dark blue Electron micrographs 1. electron-dense vesicles No mature granules $2, 142234 nm S4, lum 2. lysosomes found $3, 104 nm 3. unbounded lipid. Granules: dense 90nm clear 140 nm synaptic vesicles: 60 nm Vol. 14; No. 1 (a) (b) Figure 2 An NS cell type S2. The cytoplasm contains large neurosecre- tory granules variable in shape. An NS cell type S3. The neurosecretory granules are small and associated with glycogen granules. THE VELIGER Page 17 ae — axonal ending bm — basement membrane f — fibre gb — Golgi body ger — granular endoplasmic reticulum gly — glycogen mi — mitochondrion n —nucleus ly — lysosome (= inclusion containg lipofuscin pigment) ng — neurosecretory granule nt — neurotubule r — ribosome rm — ruptured membrane s — secretion sg — secretory granule sw — swelling on endoplasmic reticulum v — vesicle e ays o 1®® S SSS ; ©.8s OSS € (c) A mucoid cell type S4, as seen in a section of a ganglion. The granular endoplasmic reticulum develops large swellings in the early stages of secretion. Secretory granules are much larger than neurosecretory granules. THE VELIGER Vol. 14; No. 1 in histological preparations. Irregularly-shaped lipid drop- lets (li), without a limiting membrane, correspond to the colourless inclusions. Two types of secretory granules have been found in the cytoplasm of the “ordinary” neurones, one type being electron-dense and approximately 90nm in diameter (Plate Figures 3, 4, and /4, sg), the other, about 140 nm, with sparse contents of low electron density (Plate Figures 4 and 1/4, v). The former occur throughout the cytoplasm, and seem to originate from the Golgi bodies, since clusters of them are found in these regions. In some cells they occur together with the larger granules, which never oc- cur alone and seem to be associated with well developed smooth endoplasmic reticulum. The phloxinophil NS cells (S1) of the cerebral ganglia (Plate Figure 5) have less dense cytoplasm than any other neurones in Bithynia and in the snails examined they contain large numbers of immature granules near the prominent Golgi bodies, and very few mature neurosec- retory granules. Stacks of granular endoplasmic reticulum surround the indented nucleus, but other areas of cyto- plasm contain little other than neurofibrils (nf). Deposits of glycogen (gly) are much more extensive in the peri- pheral than in the central cytoplasm, often associated with lysosomes (ly), and mitochondria (mi) are more numerous centrally. The second type of NS cell (S2), which is fuchsinophil, contains neurosecretory granules (ng) which often look dumb-bell-shaped, and have an average size of 142 by 234nm (Figure 13). The granular endoplasmic reticu- lum is well developed, and tends to lie parallel with the long axis of the neurone. Neurotubules are evident peri- pherally, whilst mitochondria and Golgi bodies are con- centrated in the central cytoplasm. It is possible that small neurosecretory granules, 83 nm in diameter, arising from the Golgi bodies, fuse to form larger ones. In these spe- cimens, cells of this type located in the cerebral ganglia contain fewer neurosecretory granules than those of other ganglia, and the Golgi bodies do not seem to be active. This suggests that they may be in a resting condition. The other type of fuchsinophil NS cell (S3), is distin- guished from the former (S2) by its smaller, spherical neurosecretory granules, which have an average diameter of 104nm (Figures //, 12). The peripheral cytoplasm contains large areas of glycogen, which are absent in type S2. They are surrounded by densely packed granular endo- plasmic reticulum (ger). If there are few neurosecretory granules present, they lie close to the cisternae of the endoplasmic reticulum (Figure /3), but if there are many, they lie in the areas of glycogen deposits, and eventually completely fill them. Vol. 14; No. 1 Axones containing this type of NSM are found in the neuropile, and their endings are frequently packed with granules, together with an occasional lysosome. Other workers have reported finding small vesicles amongst larger secretory granules (Amoroso, BAXTER, CHIQUOINE & Nispet, 1964, in Archachatina, and Borer, DouMA & Koxsma, 1968, in Lymnaea), but none has been found in Bithynia. There are indications that NSM is released at the axonal endings, in that the membranes of the gran- ules are disrupted and their contents become less dense (Figure /2). In histological preparations the axonal end- ings of NS cells seem to be packed closely together in neurohaemal areas, as in Lymnaea stagnalis (Borr, 1965). However, electron micrographs reveal that they are inter- spersed amongst the fibres of the fourth type of secretory cell (S4), which are not neurones. For this reason one cannot make a quantitative estimate of NSM from par- affin sections. The secretion of cells belonging to this last category (S4) has staining reactions very similar to those of NS cells, being glycoprotein in nature. In some prepara- tions the alcian blue and alcian green method for dis- tinguishing between different acidic groups (RAVETTO, 1960) stains these cells a deep green following oxidation, as compared with the paler turquoise of the NS cells, but if smaller quantities of secretion are present the cyto- plasm is yellow, with turquoise secretory droplets, similar to the NS cells. The cells are somewhat spindle-shaped in surface view, giving rise to 2 main fibres, which lie against the peri- neurium for some distance before penetrating into the deeper parts of the neuropile. In the visceral connectives and nerves their long axes lie parallel with the direction of the nerve fibres, and the tissue of the nerves is so dense that processes smaller than the 2 main fibres given off by the cells are often undetectable. In sections of the ganglia the cells usually look club-shaped (Figure 2c). They are approximately 11.5 wm in diameter at their widest in these sections, this part being adjacent to the perineurium. The nuclei may be ovoid or cylindrical in shape, depend- ing on the quantity of secretion in the cytoplasm (Figures 2c and 7). In a cell filled with secretion, the nucleus, which is always peripheral, seems to be compressed into a cylindrical form, extending into the narrower part of the cell. If there is little secretion present the cytoplasm is dense and easily confused with that of a neurone. The peripheral region is packed with granular endoplasmic reticulum, which is sparse in the central cytoplasm. This is filled with mitochondria, lipid inclusions, pigment drop- lets (lysosomes), Golgi bodies, and glycogen. Secretory granules with a diameter of some 80 nm are scattered throughout the central cytoplasm (Figure 6, sg), and often clustered around the Golgi bodies. THE VELIGER Page 19 The granular endoplasmic reticulum of these cells is very conspicuous during the earlier stages of secretion, the cisternae becoming much more swollen than in NS cells. At first small swellings develop (Figure 6, sw), which are filled with a finely granular material. They increase in size, and possibly coalesce, until they almost fill the cyto- plasm. The ribosomes become dissociated from certain parts of the membranes (fm), and there are indications that small vesicles filled with secretion are pinched off from the reticulum at such points (Figure 8, v). Eventu- ally, the cytoplasm is filled with membrane-bounded vesicles amongst which are traces of granular endoplasmic reticulum (Figure 7). The material in the vesicles varies in electron-density, and this may be an artifact of fixation, caused by the rupture of the membranes surrounding some of the vesicles (rm). Some areas of cytoplasm con- tain patches of lighter granular secretion free in the cyto- plasm amongst traces of torn membranes (rm). In the fibrous processes of these cells vesicles tend to remain intact and electron-dense peripherally, but are swollen or burst centrally (Figures 9, /0). The fibres contain small mitochondria and tubules sim- ilar in diameter to neurotubules (Figure 7, tu). Their distal ends expand and are in direct contact with the perineurium. Pore-like structures occur at intervals in these regions; the basement membrane can be seen to dip into depressions of the cell-surface, and at these points the cell membrane is discontinuous (Figure /0, p). In some of the processes nearly all the secretory vesicles are intact, but in others they are disrupted, possibly allowing the secretion to escape into the blood spaces of the peri- neurium (Figure 9, bs). Two other types of cells have been found in, or closely associated with, the nervous system; these are the neuro- glial cells, and connective tissue cells referred to as sheath cells. Neuroglial cells, with ovoid nuclei and little peri- nuclear cytoplasm, are interspersed amongst the neurones and nerve fibres. Their fine processes ensheathe the neu- rones, but make little more than superficial indentations into the cytoplasm, unlike the extensive trophospongium of the larger neurones of pulmonates (BULLocK & Hor- RIDGE, 1965). ‘They are often laden with spherules of lipo- ' fuscin, and their branching fibres are both narrower and denser than nerve fibres. Granular endoplasmic reticulum and mitochondria predominate in the cytoplasm. In the nerves, nerve fibres are arranged in bundles, en- sheathed in neuroglial fibres. Bundles are packed so tightly together that there are very few spaces between them, and sometimes it is possible to see that such a space is continu- ous with a blood space in the perineurium. They often contain a coil of cell membrane, extending from the distal end of a fine neuroglial fibre, and it is possible that they are a means of increasing the surface area across which Page 20 THE VELIGER Vol. 14; No. 1 exchange of material with the haemolymph might occur. There is no evidence of poor fixation in these nerves to suggest that they might be artifacts. The second type of cell associated with the nervous system in Bithynia forms a network conspicuous in the connective tissue of the gonad, closely associated with branches of the visceral nerve. At points where they are in contact the nerve fibres are packed with secretory granules. The cells which make this network are similar in ap- pearance to the sheath cells described by BAxTER & NISBET (1963) in Archachatina. The elongated cell bodies attain a maximum size of 7 X 2um. The cytoplasm is filled with electron-dense vesicles ranging in size from 0.5 to 1.0um. There were no indications of different phases of secretory activity in the specimens examined. DISCUSSION One of the most difficult tasks in a study of neurosecretion using the light microscope is identification of NSM. The severe limitations of conventional staining when applied to Bithynia are indicated in the foregoing account. Only 2 types of NSM were recognizable in paraffin sections, whereas 3 can be distinguished in electron micrographs, and another type of secretion, not separable from NSM by light microscopy, bears no resemblance to it at the ultrastructural level. The number and variety of pigmented inclusions in all neurones of Bithynia, as in other proso- branchs, also complicates interpretation of paraffin sec- tions, but the pigmented inclusions are easily distinguished from NSM in electron micrographs. It is known that the presence of neurosecretory granules is not in itself sufficient evidence to establish the neuro- secretory nature of a neurone (SIMPSON, BERN «& NIsHI- oka, 1966), a point which is reinforced by the findings in Bithynia. Many neurones contain electron-dense granules, 87 to 93 nm in diameter, but they are not selectively stained, nor do their axons terminate in a neurohaemal area. This suggests that secretions of these neurones might incorporate neurotransmitters, rather than neurosecretory substances in the strict sense (neurohormones). Similar granules, thought to contain neurotransmitters have been described in “ordinary” neurones of Lymnaea (Borr, Plate Explanation Figure 3: An “ordinary” neurone with cytoplasmic inclusions con- taining a yellow pigment thought to be carotenoid. Secretory granules are particularly evident near the Golgi bodies. XX 25000 Figure 4: An “ordinary” neurone with lysosome-like bodies thought to contain lipofuscins. Secretory granules and vesicles with less dense contents are present. X 25000 Figure 5: A phloxinophil NS cell (type S1) from the cerebral ganglia. Immature neurosecretory granules occur in the vicinity of the numerous Golgi bodies. x 18750 Figure 6: An early secretory phase of a mucoid cell (type S4) of the left pleural ganglion. The cytoplasm contains not only secretory granules of the type seen in neurones, but also larger vesicles of mucoid secretion which arise as swellings on the granular endoplas- mic reticulum. X 25000 c —membrane-bounded inclusions thought to contain carotenoid pigment fm —membrane devoid of ribosomes gb — golgi body ger — granular endoplasmic reticulum gly — glycogen ing—immature neurosecretory granule li—lipid ly — lysosome (= inclusion containing lipofuscin pigment) mi — mitochondrion nf — neurofibril nt — neurotubule sg —secretory granule ser —smooth endoplasmic reticulum sw — Swelling on endoplasmic reticulum cv—clear vesicle n-— nucleus r — ribosome tu — tubule Plate Explanation Figure 7: An oblique section through the sub-oesophageal part of the visceral loop, showing a late secretory phase of a cell type S4. The cytoplasm is filled with secretory vesicles, some of which have x 12500 Figure 8: Cytoplasmic detail of a similar cell with large areas of burst. A fibre arising from the cell is devoid of vesicles. secretion within the cisternae of the granular endoplasmic reticulum. There are indications that vesicles with similar contents arise by bm — basement membrane mi — mitochondrion NSM - neurosecretory material r — ribosome sg—secretory granule bs — blood space ger — granular endoplasmic reticulum n— nucleus 1m —ruptured membrane tu -tubule being pinched off from the cisternae. x 72000 Figure 9: A neurohaemal area of the sub-oesophageal ganglion, showing axones of NS cells intermingling with fibres of cells of type S4. They terminate against the perineurium, which contains blood spaces. xX 6250 Figure 10: Fibres of cells of type S4 filled with secretion termi- nating against the perineurium and showing a pore-like area in the cell membrane. x 18750 f — fibre h — haemocoel np! — neuropile pn — perineurium s — secretion v — vesicle Pp — pore [ANpDREws] Figures 3 to 6 Tue VE.IcER, Vol. 14 No. 1 16 [ANpREws] Figures 7 to 10 Figure 10 ke A Vol. 14; No. 1 Douma & Koxsma, 1968), and Archachatina (Amoroso, BaAxTER, CHIQUOINE & NisBeET, 1964). The smaller vesicles found in the nerve fibres of Bithynia are typical of synaptic vesicles, such as those described in other gastropods by Smpson, BERN & NisHioKa (1966). Tauc & GERSCHEN- FELD (1961) have demonstrated the presence of 2 types of neurotransmitters (cholinergic and non-cholinergic, respectively) in gastropods, and it may be that the elect- ron-dense granules of Bithynia contain a non-cholinergic transmitter, whilst the small, clear vesicles in the fibres contain acetylcholine. The NS cells of Bithynia can be distinguished from these “ordinary” neurones by differences in both cytolog- ical detail and size of the secretory granules. Granules in neurones of types S1, S2, and S3 fall within the size range of neurosecretory granules described in other species, and originate in a similar way, from the Golgi apparatus (Gasper, 1966; Martoya in Grassé, 1968). Furthermore, their axones, containing neurosecretory granules, lead to specific sites where they terminate in groups against the vascular perineurium, which are comparable with the neurohaemal areas described in other species. There is a marked similarity between the S1 NS cells of Bithynia, which have an affinity for phloxin, but not for chrome haematoxylin or aldehyde fuchsin, and the “Go- mori-negative” (CDC) cells of Lymnaea, and in both species, the cells show a seasonal periodicity, perhaps in- dicating a similar role in modulating seasonal rhythms of activity. The fuchsinophilic cells S2 and S3 do not show seasonal variations, and unlike S1, seem to release their NSM, though in varying amounts, at all times. Histological evi- dence is supported at the ultrastructural level, since ele- mentary neurosecretory granules have been found at neu- rohaemal areas, as well as in the perikarya of the neurones. The functional state of the NS cells in the snails exam- ined can be assessed by the condition of the Golgi bodies, and the amount of NSM present, amongst other factors, and these indicate that the S1 cells are inactive, or at the beginning of a secretory cycle, since there are some im- mature secretory granules near the Golgi bodies, but neither the perikarya nor the axones contain NSM. The S2 and S3 cells, on the other hand, contain varying amounts of NSM, suggesting that their activity is not synchronized, and since cells with large amounts of NSM and active Golgi bodies also contain granules, some al- ready burst, in their axonal endings, this suggests that they are secreting and releasing NSM simultaneously. The mucoid cells in the nervous system of Bithynia (S4) do not seem to have any parallel in other species described in the literature. They resemble mucus secreting cells more closely than they do either neurones or glial cells, and since they are always in contact with the perineurium it is possible that they are derived from the perineurium THE VELIGER Page 21 itself. The sheath cells of Archachatina (Amoroso, Bax- TER, CHIQUOINE & NisBeT, 1964) occupy a similar posi- tion, but they do not show the same ultrastructural char- acteristics. Furthermore, the mucoid cells are restricted in their distribution to NS and neurohaemal areas, whereas the sheath cells are widespread. In Bithynia, cells identical with the sheath cells are closely associated with peripheral nerves. It has been suggested that such cells have a supporting or storage function, but these do not seem to be likely roles for the mucoid cells. Their primary function would appear to be secretion. Since there are indications that the secretion is released into blood spaces of the peri- neurium through temporary pores, it can only be sug- gested that it has an endocrine function. No other possible endocrine glands have been found in Bithynia, but groups of cells to which this function has been attributed in other gastropods (Martoya in Grassé, 1968) are aggregated into discrete bodies outside the nervous system. It may be that intimate association be- tween neurosecretory and endocrine glands is the more primitive condition, which has been retained in Bithynia. Other prosobranchs were examined in the hope of finding similar cells, and although none was found in other meso- gastropods, some were located in the visceral ganglion of Theodoxus fluviatilis (Linnaeus, 1758). These, too, are localized in what appears to be the main NS area of the nervous system. Inactive mucoid cells in Theodoxus are very like the neurones, which are multipolar, but when filled with secretion they become sac-like in appearance, and bulge into the connective tissue of the perineurium. The close association between these unusual cells and NS cells in 2 different species of gastropods suggests some functional connection, and it is difficult to believe that cells concerned solely with storage or support would secrete glyco-proteins into the blood. A study of the fine structure of the nervous system of Bithynia tentaculata thus supports the view that certain cytologically distinct neurones are probably neurosecre- tory. In addition, it has revealed the presence of an entirely different type of secretory cell within the nervous system, the possible role of which merits further consider- ation. SUMMARY Examination of the nervous system of Bithynia tentaculata (Linnaeus) by electron microscopy has confirmed the presence of secretory granules in neurones identified as possible neurosecretory cells with the light microscope. They can be divided into 3 groups on the basis of differ- ences in the secretory granules and organization of the cytoplasm. Secretory granules are also found in the major- ity of ordinary neurones, and are thought to contain neurotransmitters. Pigment spherules in the neurones, Page 22 THE VELIGER Vol. 14; No. 1 which can be confused with neurosecretory material in paraffin sections, can easily be distinguished in electron micrographs. There are 2 distinct groups: electron-dense vesicles, thought to contain carotenoids in living neurones, and lysosome-like bodies containing lipofuscins. Neurosecretory and neurohaemal areas of the nervous system not only contain the neurosecretory cells, but also include cells which are not neurones, and which secrete a glycoprotein. There are indications that the secretion is released into the blood through temporary pores, and it could be that they have an endocrine function. A network of fibres which is conspicuous in paraffin sections of the gonad is similar in fine structure to the sheath cells described in the nervous system of Arch- achatina. The fibres are laden with protein spherules when the gonad is mature, and they may be concerned with storage. ACKNOWLEDGMENTS I am indebted to Dr. R. Coleman for his invaluable advice on the techniques of electron microscopy; to Mr. R. L. Jones, for his assistance in the use of the electron microscope and for the preparation of the plates, and to Professors H. A. Bern and A. Graham, for their helpful criticism of the manuscript. I also wish to express my gratitude for a grant from the Bedford College Research and Publications Fund to cover the cost of production of the plates. Literature Cited Amoroso, E. C., M. I. Baxter, A. D. CHIQUOINE & R. H. NisBet 1964. The fine structure of neurons and other elements in the nervous system of the giant African snail Archachatina margin- ata. Proc. Roy. Soc. Biol. 160: 167 - 180 ANDREWS, ELIZABETH B. 1968. An anatomical and histological study of the nervous sys- tem of Bithynia tentaculata (Prosobranchia), with special ref- erence to possible neurosecretory activity. Proc. malacol. Soc. London 38: 213 - 232 Baxter, M. I. « R. H. NisBer 1963. Features of the nervous system and heart of Archacha- tina revealed by the electron microscope and by electrophysio- logical recordings. Proc. malacol. Soc. London 35: 167-177 Borer, H. H. 1965. A cytological and cytochemical study of neurosecretory cells in Basommatophora, with particular reference to Lym- naea stagnalis L. Arch. néerl. Zool. 16: 313 - 386 Boer, H. H., EvisaseETH DouMA & JENNEKE M. A. KoksMA 1968. Electron microscope study of neurosecretory cells and neurohaemal organs in the pond snail Lymnaea stagnalis. In: Studies in the structure, physiology and ecology of molluscs, ed. VERA FRETTER. Symposia Zool. Soc. London no. 22. London, Acad. Press Buttock, THEODORE HotmEs & G. ADRIAN HorRIDGE 1965. Structure and function in the nervous system of inverte- brates. W. H. Freeman and Co., San Francisco & London, 2 vols. Gase, M. 1966. Neurosecretion. Oxford, Pergamon Press Jeon, K. W. 1965. Simple method for staining and preserving epoxy resin- embedded animal tissue sections for light microscopy. Life Sci. 4; 1839 - 1843 Martoya, MIcHELINE 1968. Neurosécrétion et glandes endocrines des Mollusques autres que les Céphalopodes. In: Traité Zool. V (III) Mol- lusques Gastéropodes et Scaphopodes., ed. P-P Grasse. Paris, Masson, publ. RavettTo, CarRLo 1964. Alcian blue — Alcian yellow: a new method for the identification of different acidic groups. Journ. Histochem. Cytochem. 12: 44 - 45 REYNOLDS, Epwarp S. 1963. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. Journ. Cell Biol. 17: 208 - 212 Smpson, Leonarp, Howarp ALLEN BERN & RicHarp Isz1 NIsHIOKA 1966. Survey of evidence for neurosecretion in gastropod mol- luscs. Amer. Zool. 6 (2): 123 - 138; 6 text figs. Tauc, L. « H. M. GerscHENFELD 1961. Cholinergic transmission mechanisms for both excitation and inhibition in molluscan synapses. Nature, London 192: 366 - 367 Watson, M. L. 1958. Staining of tissue sections for electron microscopy with heavy metals. Journ. Biophys. Biochem. Cytol. 4: 475 - 478 Plate Explanation Figure 11: Cytoplasmic detail of an NS cell type S3, showing granular endoplasmic reticulum surrounded by clusters of secretory granules in a region filled with rosettes of glycogen. 50000 Figure 12: The axonal ending of a similar cell in a neurohaemal area. Distally the membranes of the secretory vesicles appear to burst and release the secretion. 50000 cv —clear vesicle ng — neurosecretory granule n —nucleus T — ribosome gb — Golgi body ger — granular endoplasmic reticulum np—pore in nuclear membrane NSM - neurosecretory material Im — ruptured membrane Figure 13: Cytoplasmic detail of an NS cell of type S2, showing secretory granules of variable size lying amongst rosettes of glyco- gen. x 50000 Figure 14: Cytoplasmic detail of an “ordinary” neurone containing secretory granules and paler vesicles, possibly concerned with the secretion of neurotransmitters. x 45000 gly — glycogen mi — mitochondrion pn — perineurium s — secretion sg—secretory granule Tue VEuicrER, Vol. 14 No. 1 [ANDREWS] Figures 1] to 14 : pe : ! Vol. 14; No. 1 THE VELIGER Page 23 The Ecology of the Nest-Building Bivalve Musculus lateralis Commensal with the Ascidian Molgula occidentalis GERARD A. BERTRAND Department of Oceanography, Oregon State University, Corvallis, Oregon 97330 (2 Plates; 3 Text figures) POPULATION STUDY Musculus lateralis (Say, 1822) is a small uncommon bi- valve found from Delaware Bay southward throughout the Gulf of Mexico to the West Indies (Jounson, 1934). It is normally free living, attached to rocks, pilings, or any ‘hard shallow-water substrate. It has not been reported from an ascidian. A general bivalve-ascidian relationship has been known for over a hundred years. JEFFREYS (1863) reported Mo- diolaria (= Musculus) marmorata (Forbes, 1833) from the test of Ascidia mentula Miller, 1776 on the coast of England. Meissner (1893) described this same species as parasitic on Ascidiella virginea (Miller, 1776). Bour- DILLON (1950, 1955) redescribed M. marmorata as a commensal on a number of ascidians, including Styela plicata (Lesueur, 1823). AtpricH (1955) reported a bivalve-ascidian relationship from the western Atlantic coast of this country. He found Molgula manhattensis (DeKay, 1843) attached to the protruded siphon of the clam Mya arenaria Linnaeus, 1758. In this case the tunic- ate was a hindrance to the clam because it could not withdraw its siphon into the burrow. The host animal for Musculus lateralis in my study was Molgula occidentalis Traustedt, 1883. Molgula occz- dentalis is found in abundance on the sand-mud substrate in shallow water from Cape Cod throughout the Gulf of Mexico and the West Indies to Brazil. It is present, and easily collected, in the study area, a protected shallow bay, Alligator Harbor, Franklin County, Florida. Molgula oc- cidentalis, although a simple ascidian, is usually found growing in clumps of 3 to 15 in this area. Because of its size and secure attachment in the soft substrate, it attracts Many organisms seeking shelter and protection. One of these is the bivalve Musculus lateralis. The population sample in this study was based on 50 specimens of Molgula occidentalis taken in Alligator Har- bor at a depth of 2-3 meters in March, 1967. The bi- valves were removed from the tunicate with a probe and the total length measured to the nearest millimeter with an ocular micrometer. Musculus lateralis was present on 37 of the 50 specimens (Figure 1). A total of 412 were recorded with an average of 11.1 for the 37 tunicates with Musculus. The range in numbers was 0 to 48. Of the 412 taken, 389 were measured. Those not measured had both valves chipped or broken when removed from the tunic- ate. The size range was 2 to 9mm and the average size was 6.7 mm. An earlier collection of 35 Molgula occidentalis was dredged off Turkey Point in Franklin County, Florida in December, 1966, at a depth of 5- 6m. A third collec- tion of Molgula, composed of 65 live beach specimens, was made after a storm in March, just east of the Florida State Marine Laboratory at Alligator Harbor. The speci- mens of Musculus lateralis from these two collections were counted and recorded, but not measured. A collection of 12 Styela plicata was dredged in Alligator Harbor in March, and another of 100 was made from a float at the end of the dock at the marine laboratory. The Musculus lateralis on these specimens were also counted and re- corded, but not measured. One specimen of S. plicata from Turkey Point was also obtained and checked. The 35 specimens of Molgula from the Turkey Point collection yielded 1487 Musculus lateralis for an average of 42.4 per tunicate. The range was from 17 to 77 (Figure 2). All of the tunicates had Musculus present. From 65 Molgula occidentalis picked up alive on the beach in Alligator Harbor, there were no M. lateralis. Of the Styela plicata examined, the 12 specimens from Alligator Harbor yielded 174 Musculus for an average of 14.5 per tunicate. The range was 4 to 30 (Figure 3). The single Turkey Point specimen yielded 90 M. lateralis. The 100 specimens taken from the float at the end of the dock had no Musculus attached. Page 24 15 10+: Number of Molgula occidentalis THE VELIGER Vol. 14; No. 1 Average of 11.1 mussels/tunicate with mussels Number of Musculus lateralis Figure 1 The distribution of Musculus lateralis on Molgula occidentalts from the Alligator Harbor Collection of March, 1967 Number of Molgula occidentalis 20 30 40 Number of Musculus lateralis Average of 42.4 mussels/tunicate 50 60 70 80 Figure 2 The distribution of Musculus lateralis on Molgula occidentalis from the Turkey Point Collection of December, 1966 DISCUSSION If Musculus lateralis is present at all on Molgula occi- dentalis, it is usually there in abundance. The explana- tion for this can be arrived at by an examination of its mode of reproduction. This species and other members of the genus lay egg-strings on the inside of a prepared nest. Here the eggs hatch and develop without leaving the nest. The postlarvae remain in or near the nest, feeding from the parental currents (MERRILL & TURNER, 1963; MacGinitiz, 1955; OckeLMAN, 1958). As in the case of many organisms that care for the young, the eggs are large and few in number (THorson, 1935). If the bivalve secures a place to build a nest on the tunicate, it is in a position to increase its numbers quickly. If the tunicates are attached in a clump, and mussels are on one tunicate, they are likely to be on all tunicates. Vol. 14; No. 1 Average of 15.3 mussels/tunicate es, Fa ae i ae 10 20 Number of Musculus lateralis nN Number of Styela plicata Figure 3 The distribution of Musculus lateralis on Styela plicata from the Alligator Harbor Collection of March, 1967 Musculus lateralis is usually a hard-bottom dweller and its mode of reproduction keeps it from colonizing new areas rapidly. A clear area of sand or a distance of open water can prevent it from inhabiting certain new areas. The float from which the 100 specimens of Styela plicata were taken was one of these areas. The tunicate larvae are pelagic and grow rapidly after attachment (Grave, 1936; Brerritt, 1950). The adult tunicates on the float had not yet been reached by Musculus nor many of the epifaunal organisms. The 65 beach specimens came from an area just east of the marine laboratory. This area is very sandy and the epifauna is scarce. Molgula occidentalis larvae can settle in this area on a small shell fragment or any small hard particle. Their tenuous position is evidenced by their washing ashore during a storm. All 65 ascidians exam- ined were solitary, that is, not attached to other Molgula. Like the Styela on the float, they were free of Musculus lateralis. Conversely, those individuals living in a sand-mud sub- strate had a large number of Musculus lateralis attached. The individual tunicates from Turkey Point were attached to each other in clumps of from 2 to 10. These yielded the largest total number of Musculus, with a high aver- age number per tunicate. The greater depth of water, lesser turbidity, greater concentration of nest-building materials, and what appeared to be a larger average size of the tunicates, probably contributed to the greater con- centration of mussels on the tunicates. BourbiLton (1955) found that the number of Modio- laria marmorata (which is about the same size as Muscu- lus lateralis) on Styela plicata varied greatly between individuals. The largest number of Modiolaria he found in a single Styela was 61. The largest number found in my study was 90. His count was made from a tunicate 5 cm long, whereas the Turkey Point specimen used here THE VELIGER Page 25 was about 8cm long. The percent of tunicates from Bourdillon’s study that contained Modiolaria varied from 5 to 100%, in the present analysis from 0 to 100%. NEST BUILDING Many species of bivalves attach themselves to solid objects by means of a byssus, but in the family Mytilidae it is most fully developed. Wurre (1937) described in detail the process by which byssal threads are formed in Mytilus edulis Linnaeus, 1758. The foot has a posterior groove continuous with the byssal aperture. The groove itself and special byssal glands at their base secrete a substance called conchiolin. The conchiolin flows down the groove which terminates in a sucker. The sucker itself secretes a cement which adheres when placed in contact with the substrate. The groove opens and the conchiolin thread, on exposure to sea water, hardens. The formation of these threads is usually confined to spinning a byssus, a strong band composed of many threads, but some species have developed the ability to weave these threads into a protective covering or nest. Robertson described this type of nest building of Lima hians (Gmelin, 1791) in JerFReys, 1863, as did Git- cHrisT (1897). JoHNson (1931) did the same for Lima inflata Lamarck, 1819. Haas (1942, 1943) described the nest of Diplodonta orbella (Gould, 1851) and Cooperella subdiaphana (Carpenter, 1864) as being composed pri- marily of sand adhering to mucus. Thus, this latter type of nest is not composed of threads as is that of L. hians. Instead, a large ball of mucus forms at one end and grad- ually accumulates particles. The volume of mucus in- creases until the bivalve is successfully camouflaged. MacGinitie (1959) described the nest of Musculus discors (Linnaeus, 1767) from the coast of Alaska. The nest-building of this species was later described from laboratory observations by MERRILL & TURNER (1963). This nest proved to be of the former type or a thread nest. As yet, no one has described the nest, or followed the nest building, of M. lateralis. LABORATORY OBSERVATIONS In March, 1967, 50 live specimens of Musculus lateralis were removed from their nest of Molgula occidentalis and placed in aquaria in running sea water at the Florida State Marine Laboratory. The bivalves were put into glass petri dishes which were suspended in the aquaria in a wire net fashioned of stainless steel. Additional petri dishes Page 26 with new Musculus were added in the course of the ex- periment to obtain a comparison of old and new nests. The water temperature during the experiment fluctuated between 19 and 25° C. The flow of water into the aquaria remained relatively constant except for one 12 hour period and one 4 hour period in which the salt water pump failed. The aquaria were not lighted at night except during occasional checks on nest building when indirect lighting was used. Like most mytilids that secrete a byssus, the first action of Musculus lateralis, when put in a new environment, was to secrete a few threads to secure an attachment to the substrate. This was done within the first 2 hours for 44 of the 50 specimens in the aquaria (Figure 4). Those that did not initially secrete a byssus usually did not com- plete a nest and subsequently died. The specimens were placed during daylight, either in late morning or early afternoon; consequently, once the initial threads were out, activity ceased until dark. After putting out the initial threads, Musculus lateralis pro- ceeded to build the nest in the following fashion. First, a ball of mucus formed at the posterior end of the speci- men. As the threads were formed, drops of the mucus stuck to them. This feature made it easy to detect the newly formed threads. In the aquaria each bivalve initi- ated building while lying on its side on one valve. The foot extended and attached a series of threads directly in front of the anterior margin of the valves. After 15 to 20 threads were in place, the foot reached over the top valve and attached another series to the floor of the petri dish on the opposite side (Figure 5). During the 10-hour period in which weaving took place on the first day, about 40 strands were attached. The placement of these threads over the top valve tended to lift the mussel more into an upright position at about 30° from the horizontal. With further building, some individuals completely righted themselves and were positioned on the dorsal surface, while others remained on one valve in the completed nest. The second day each mussel continued putting out threads in a radial manner until the shell was completely sur- rounded by threads radiating from the byssal aperture. At this point there were about 100 threads surrounding the shell (Figure 6). After this basic pattern of the nest was formed, the mussel began secreting longer threads farther away from the shell and reinforcing the already existing threads. At this point the mussel seemed to be enclosed in a tent with the shell margin acting as the top ridge. The threads themselves were not connected to the shell in any way, but to the byssal aperture. When the valves were open for feeding, the byssal retractor muscle and the anterior and posterior adductors were THE VELIGER Vol. 14; No. 1 relaxed. The byssal aperture was raised dorsally toward the margin of the shell and the threads were loose. Upon closing, the byssal retractor pulled the aperture back and with it the threads of the nest. The valves closed and the nest tightly covered the shell. At the end of a week the nest was composed of about 250 threads. The threads themselves, when first secreted, were almost transparent. They were extremely thin but strong. As the threads hardened, the color changed from transparent to yellow and then to brown. The appearance of the nest at this time changed considerably. Sand, detri- tus, algae, and other organisms began to accumulate on and in the nest network. In one instance a piece of shell material 2mm long was incorporated into the nest. At any time from 3 to 4 weeks the bivalve became completely hidden within the nest (Figure 7). All the while, Muscu- lus lateralis added new threads to the nest, but the pro- gress was slower. The weaving was intermittent and threads were not added every night. Each specimen building a nest on the vertical wall of the petri dish followed the same pattern as the others except that, because of its position (dorso-ventral with one valve against the glass) it secreted a larger number of threads on the dorsal side before going over the outer valve to secure threads underneath. The threads of one specimen did not attach in any way to its own shell, but this was not so of other shells. Three specimens in close proximity built their nests in an over- lapping fashion with the threads of one attached to the petri dish and to other shells. The nests so constructed formed an intertwining network which covered the group completely. The shells within the nests were undetectable after 3 weeks except when the mussel was feeding. Except for feeding and nest building, the valves re- mained closed. During daylight for the nearly two months the organisms were kept in the aquaria, only one individ- ual was seen in any activity other than feeding. This specimen was not one from the petri dishes, but one previously placed on the bottom of a 5-gallon capacity aquarium. It moved across on the bottom and climbed the vertical side of the aquarium to a height of 8 inches. In this position it put out a series of threads to secure attach- ment and then ceased movement. The foot of Musculus lateralis is quite remarkable. When fully extended, it is longer than the specimen itself. When first observed, the foot looks like a cream-colored nematode leaving the bivalve. This foot is extremely flex- ible as was evidenced by the manner in which the bivalve climbed the aquarium glass. The foot, like that of M. discors, is equipped with a pedal disc which can attach a byssal thread when placed against the substrate. During Tue VE.icER, Vol. 14 No. 1 [BERTRAND] Figures 4 to 7 Figure 6 The Nest Building of Musculus lateralis Figure 4: 2 hours Figure 5: 24 hours Figure 6: 2 days Figure 7: 1 week Bar is 1 cm long Vol. 14; No. 1 horizontal movement along a flat surface the foot is ex- tended ahead of the bivalve, attaches, and on contraction pulls the valves up to the new position. This is done without the secretion of any byssal thread. To move verti- cally on the glass, the foot is extended, attached, and the body of the shell drawn up. A thread is then secreted and the shell is suspended while the foot extends to its maxi- mum length and attaches again. The shell is again drawn upward with the byssal thread either being broken or released. With this manner of movement, the bivalve was able to move the distance in a matter of minutes. Although this specimen was the only one observed in motion, several others managed to negotiate the distance. One specimen made the trip on 4 successive nights after being replaced on the bottom each day. If the Musculus are open, the gap of the valves is wide and very noticeable. When the Molgula are first collected, the Musculus valves tend to gape and the number of bivalves can be counted. FIELD OBSERVATIONS The process of nest building by Musculus lateralis on Molgula occidentalis in the field is the same as in the laboratory, but the result is different for the following reason. The body of the shell, either partly or completely, is impressed into the test of the ascidian. The older the ascidian grows and the longer Musculus is embedded, the shorter the distance to the edge of the indentation be- comes. Thus, the early nest material piles up on the top and sides of the outward oriented shell margin. This network provides protection and shelter for a myriad of small invertebrates. Nests of larger specimens taken in the field appear to have no symmetry or pattern as do the newer nests fashioned in the laboratory. The “bump” that appears on the outside of the test denoting the presence of a single bivalve on a small surface is entirely missing when a large number of intertwining Musculus is present. The nests blend together to form a mat-like effect and a gener- ally even surface results. Although the bivalve is embedded in the test, it does not break the strong cuticle covering the test. Instead, the flexible cuticle is pushed inward until a depression is formed. When the bivalve closes its shell, the threads become tight and exert a downward pressure on the shell. Through this pressure and friction of movement within the nest, the cuticle is gradually pushed into the test until the depression is made. These depressions are permanent in that they remain when the mollusk is removed. It was observed that the depression under dead valves was not THE VELIGER Page 27 as deep and the cuticle seemed to be returning to normal through growth. This was especially true in the top third of the test surrounding the siphons. In this area the test was several millimeters thick, but was composed of the same milky cellulose material that made up the remain- der of the test. In this area some indentations caused by Musculus were up to 5mm deep from their lip. Small (2 - 3 mm in diameter) whitish circles scattered randomly on the inside of the test could be seen when the test was inverted. These “scars,” at the base of the embedded Mus- culus, were most noticeable on the ventral two-thirds of the test where it was thin, but they were discernible even in the thickened anterior portion. A few spots were seen where no Musculus were embedded and the exterior of the test appeared normal. From these scars the past pre- sence of a bivalve or some attached foreign object can be deduced. While almost all of the larger specimens were found in nests, small mussels (2 mm or less) did not build nests of their own, but lived within the nest of an adult, feeding from the water currents created by it. This is not strange in view of the reproductive habits of Musculus. During the entire study, two adults were never taken from the same nest. DISCUSSION The question of how Musculus lateralis comes to lie em- bedded in the tunic of Molgula occidentalis is important because it could indicate the presence or absence of host specificity. BourDILLON (1950) stated from experimental evidence that Modiolaria marmorata became embedded in the test of Styela plicata because of its chemical attrac- tion to the cellulose nitrates which compose the test. Thus, the attraction to the tunicate would be primarily a chem- ical one. He further stated that the mechanical stimulus of the water currents created by the tunicate played no part in the attraction. In a later paper (BourpiLtton, 1955) he reversed the earlier proposals and said the attraction of the bivalve to the tunicate was due entirely to the mechanical attraction to the test because of its consistency as a substrate for inclusion. He also reaffirmed his position that the water currents produced by Styela plicata played no part in the attraction. As was previously stated, Styela plicata is abundant in Alligator Harbor and is used by Musculus lateralis as a substrate for embedding and nest building. Musculus la- teralis embeds in Styela in a wide band composing the middle third of the elongated test. In this position it can Page 28 THE VELIGER Vol. 14; No. 1 be as much as 2 to 4cm from the siphon openings. This does not remove the bivalve from the effect of the current, but it does lessen it. This is not so with Musculus in Molgula. The majority of the mussels are embedded in the dorsal third around the siphons and the currents cre- ated affects them noticeably (Figures 8, 9). One probable reason for Musculus to attach to the upper third of Mol- gula is that the test in this area is much thicker than on the remainder of the tunicate and more susceptible to indentation. Molgula occidentalis is a simple ascidian; that is, each individual is enclosed within its own test. However, these individuals are often colonial, attaching to each other by the sides and base. Single ascidians have less of a suppor- tive base and sink into the mud or sand bottom for the lower third of their length. Thus, the space available for Musculus lateralis to attach is restricted. There is evidence that Musculus nesting low in the crevice between individu- als are in a dangerous position. Several specimens were found dead, trapped in their nests between the growing tunics of Molgula. Whether these died before or after being covered cannot be determined, but live individuals are often found in the crevice. In the course of the study, no abandoned nests were observed, although many dead individuals were found. The dead Musculus were within the nest and their con- dition could not be determined until removed. In the aquaria some specimens that built nests later died but did not abandon their nests. No abandoned nests were seen in the laboratory specimens. BourpiLton (1955) found that Modiolaria marmorata took 24 hours to entrench in the test of Styela plicata. Although fixation in the test of Molgula occidentalis by Musculus lateralis was not observed in the laboratory, it is thought that it would take at least several days. This is due to the much denser consistency and rigidity of the test of Molgula. Styela plicata is much more malleable and, by using the little finger and steady pressure, one can make a Musculus-sized indentation in a matter of min- utes. This is not so for Molgula. The young of Musculus remain within the parental nest. The young bivalve that leaves the parental nest (less than 2 mm) is free to invade other young Molgula or to settle on the same specimen, ‘The smallest specimens taken within their own nests were 2 to 3mm long, while the largest taken within the parent’s nest were slightly less than 2mm long. Often larvae of Molgula occidentalis settle and grow, apartment house fashion, on the adult organism. These specimens present an ideal habitat for young of Musculus lateralis since they, too, settle on the dorsal third of the test. As we have seen, the locomotive powers of this bivalve are considerable, and the short distance necessary to travel to reach this new area is negligible. The adaptation of nest building in Musculus probably developed because of predation. Musculus lateralis has a very thin shell and those specimens that did not build a nest and remained unprotected could have been elimi- nated. Even with the protective nest, predation is a prob- lem. Many of the dead pairs of valves found within their nests showed evidence of drilling. The holes were very small but clean, such as those made by the dove shells of the family Columbellidae. A number of these tiny gastropods, Anachis spp., and many pyramidellids, were found on or in the material collected on the test of the tunicate. Because empty nests were not found, and the dead specimens showed little evidence of violence other than those with the small bore hole, it is thought that predation on a large scale is not present in the Musculus inhabiting Molgula. The tunicate itself seems unaffected by the presence of the bivalve. Although the test is riddled with indentations, the cuticle is not broken and the functions of the ascidian are unhindered. The bivalve population is dense around the siphons, but this does not seem to impede the flow of water to and from the siphons. To define the relationship of Musculus lateralis to Mol- gula occidentalis a number of ideas must be considered. First, M. lateralis is usually a free-living species. Dr. Ar- thur A. Merrill has taken literally thousands from the east coast of Florida (personal communication). Second- ly, the bivalve is not in any way specific to Molgula since it is found on Styela and a number of other unidentified ascidians. Lastly, in the absence of suitable bottom sub- strate in Alligator Harbor, the ascidians would seem to be a natural place for attachment as is shown by the large number of hard bottom epifaunal organisms found associated with the tunicate colonies. On the other hand, Musculus lateralis inhabits a par- ticular part of the ascidian and builds its own nest. The reproductive habits of Musculus are of tremendous ad- vantage in the relationship when coupled with those of Molgula. The bivalve is able to immediately colonize new areas and maintain the relationship through generations. Musculus lateralis is a filter feeder and must derive some benefit in feeding from the strong currents created by Molgula. The relationship of Musculus lateralis to Molgula oc- cidentalis would certainly seem to qualify under the defi- nition of commensalism, in which one species is benefitted in an intimate relationship, while the other is either bene- fitted or unaffected. For this reason, M. lateralis is con- sidered to be a facultative commensal of Molgula occi- dentalis. Tue VE.icER, Vol. 14 No. 1 [BERTRAND] Figures 8, 9 X-ray Photograph of Musculus lateralis on Molgula occidentalis Twice natural size Figure 8: The incurrent siphon taken from the tunicate in Figure 9 Figure 9: The tunicate with the embedded bivalves Vol. 14; No. 1 THE VELIGER Page 29 ACKNOWLEDGMENTS I wish to thank M. Greenberg, R. Yerger, H. Smith, R. Turner, A. Merrill, and L. Small for their valuable assist- ance in various aspects of this study. I am particularly indebted to Albert W. Collier of Florida State University for support and encouragement during the course of the study. John V. Byrne and Andrew G. Carey, Jr. made pub- lication possible through their support while the manu- script was in preparation. Acknowledgment also is made to the Sea Grant Program, Grant GH-10. Literature Cited ALDRICH, FREDERICK A. 1955. A new relationship involving Molgula manhattensis (DeKay) and Mya arenaria L. Notul. Nat. Acad. Sci. Phila. 274: 1-3 BErRiLx, N J. 1950. Notes sur le commensalism des Modiolaria et des As- cidies. Vie et Milieu, Paris, 1: 198 - 199 1955. Notes sur les Modiolaria habitant la tunique des Asci- dies. Aix-Marseille, Stat. Marit. d’Endoume 15: 15 - 24 GitcuristT, J. D. F. 1897. Lima hians and its mode of life. Hist. Soc. Glasgow. 4 (n. s.): 218 -225. Proc. Trans. Nat. Grave, C. 1936. | Metamorphosis of ascidian larvae. Pap. Tortugas Lab. (1935) 29: 209 - 291 Haas, Fritz 1942. The habits of some west coast bivalves. Nautilus 55 (4): 109-113. 1943. Malacological notes - III. Zool. Ser. Field Mus. Nat. Hist. 29 (1): 1-23; figs. 1-8. JEFFREYS, JOHN Gwyn 1863. British Conchology. 3: 1-393; plts. 1-8 JoHNson, CHARLES WILLISTON 1931. Lima inflata and its nest. Nautilus 44 (4): 126. 1934. List of marine mollusca of the Atlantic coast from Labrador to Texas. Proc. Boston Soc. Nat. Hist. 40 (1): Vol. 2. John Voorst, London, 1 - 204 (July 1934) MacGiniTiz, GrorcE EBER 1955. Distribution and ecology of marine invertebrates of Point Barrow, Alaska. Smithson. Misc. Coll. Publ. 4221. 128 (9): 1-201; plts. 1-8. MacGinirTiz, Nettie 1959. Marine molluscs of Point Barrow, Alaska. Nat. Mus. 109: 59 - 208; 27 pits. MEISSNER, M. 1893. Das Einnisten des Crenella marmorata in den Mantel der Ascidiella virginea. Sitz.-Ber. Ges. naturf. Freunde Berlin, No. 10 Merritt, ArTHUuR S., & RutH D. TurNER 1963. Nest building in the bivalve genera Musculus and Lima. The Veliger 6 (2): 55-59; plts. 9-11 (1 October 1963) OcKkELMAN, W. K. 1958. The zoology of East Greenland. Marine Lamellibranchi- ata. Medd. Gronland, Kgbenhavn. 122 (4): 1-256; pits. 1-3; 29 text figs. THORSON, GUNNAR 1935. Biologische Studien tiber die Lamellibranchier Modio- laria discors L. und Modiolaria nigra Gray in Ostgrénland. Zool. Anz. 111 (11-12): 297 - 304. Waite, KaTHLEEN M. 1937. Mytilus. L. M. B.C. Memoirs XXXI. The Univ. Press of Liverpool. 1-117; plts. 1-10 Proc. U.S. Page 30 THE VELIGER Vol. 14; No. 1 A New Engina in Florida BY M. ELLEN CROVO 2915 South West 102"* Avenue, Miami, Florida 33165 (1 Plate) For SOME TIME, a pale colored Engina has been identified by Florida collectors as merely a color form of E. turbin- ella (Kiener, 1835-36), which is easily recognized by its jet black ground color with a row of large white spots along the shoulder. More careful study of these two En- gina forms, especially through the medium of good photo- graphs showing details of sculpture, indicate that they represent two distinct species. Specimens of the new species have been collected in lim- ited numbers consistently over the years in the cleanings and washing from specimens of Spondylus americanus Hermann, 1781, which were collected from depths of 90 to 120 feet, beyond the reef, off Boynton Beach, Florida. It is possibly an offshore species that may come shoreward only for a limited period to spawn. Engina corinnae Crovo, spec. nov. (Figures 2, 3) Description: Shell biconic, solid; spire and canal of nearly equal length; spire whorls about 5, topped by a small bulbous nucleus of 2 smooth whorls; subsutural zone a wide, deeply sunken, nearly smooth space, except for weak axial undulations across it; sculpture of 7 low axial riblets that are most strongly developed on the middle zone, forming a broad shoulder overridden by coarse spiral cords, 2 on the spiral whorls, increasing to about 10 on the body whorl and across the base and canal. Color light tan, with 2 (rarely 3) lines of chocolate brown dashes between the axial riblets (details of sculpture and pattern shown in Figures 2 and 3). Base of pillar slightly perfo- rate; operculum corneous, varying in color from tan to wine red. The specific distinctions between Engina corinnae and E. turbinella are best illustrated by the figures. In the case of E. corinnae: its narrower, more elongate form; less angulate shoulders, more heavily sculptured with large axial riblets; a narrower aperture with a large, spreading parietal callus that is more strongly denticulate on both sides. Holotype: Length 13mm; diameter 8} mm; MCZ no. 277496. Paratypes: Length 12mm; diameter 8mm; PRI no. 28273. Other paratypes MCZ no. 277497. Type Locality: Off Boynton Beach, Palm Beach County, Florida; 30°00’ N, 79°57’30” W. The species is named for Corinne E. Edwards in recog- nition of her achievements as an ardent collector of marine life as well as an educator in popular subjects on natural history. Tue VE icER, Vol. 14 No. 1 [Crovo] Figures / to 3 Figure 2 Figure 1: Engina turbinella (Kiener, 1835-1836) Figures 2 and 3: Engina corinnae Crovo, spec. nov. Vol. 14; No. 1 THE VELIGER Page 31 A Recent Record of a Rock-Boring Clam, Kirfaea crispata (Linnaeus) from Newfoundland ' K. S. NAIDU’ (1 Text figure; 1 Table) Turner (1954) MADE AN EXTENSIVE review of the Phola- didae of the western Atlantic and the eastern Pacific. In her monograph mention is made of an observation on Zirfaea crispata from the Newfoundland area. There is, however, no mention of the locality from which the speci- men had come. The specimen examined by her carried no information on the details of collection (date, location, or collector). All that is known of the specimen is that it was contained in the large personal collection of Mr. John B. Henderson, portions of which were donated to the United States National Museum over the years from 1913 to 1920. The bulk of his collection from the New England area was deposited in 1915 (Byas, pers. comm.). Attempts to trace the exact source of the specimen have so far failed. This note represents a possible origin of the speci- men now in the United States National Museum (cat. no. USNM 462636; length [antero-posterior axis], 39.2 mm; height [dorso-ventral axis], 26.3 mm). During the course of giant-scallop investigations in Port au Port Bay, Newfoundland, evidence from charac- teristic rock borings in loose beach rocks and visible submerged bed rock indicated the possibility of the pres- ence of boring clams in that area. On further investigation several live specimens were discovered in shallow water below low tide mark (Figure 1). The bivalves were found in depths ranging from 2 to 4 fathoms. While the clams in the upper extremity of their range were found in fairly continuous submerged bed rock, those nearer the shore were usually in small scattered fragments broken off from the main bed rock, perhaps by ice and tidal action. The animals were small (Table 1) and were found boring into unconsolidated silt stone. The rock had a hard- ness of 2-3 (Mohr’s scale), the hardness being slightly ‘ Studies in Biology from Memorial University of Newfoundland No. 241 2 Present address: Fish Stock Evaluation Branch, Fishery Re- sources Division, Food and Agriculture Organization, 00100 - Rome, Italy Figure 1 Specimens of Zirfaea crispata collected from Port au Port Bay, Newfoundland less on the exposed surfaces where weathering had taken place. Local leaching out of carbonate material may ac- count for this. Laboratory analysis of rock samples indi- cated that about 50% of the rock was made up of carbonates (all carbonates), the rest of the rock consisting of finer organic and clayey material. Thin sections of the rock indicated very fine grain material (modal size 100u to 250) with secondary pyrite inclusions. Page 32 THE VELIGER Vol. 14; No. 1 Table 1 Soon after their discovery the clams were sent to Dr. R. D. Turner who kindly confirmed the identification. Length-height ratio of Zirfaea crispata from Port au Port Two of the specimens examined have been deposited in Bay, Newfoundland (length measured in an antero- the National Museum of Canada. The accession number posterior axis and height from dorsal to ventral extremity for these is 68-210 and the NMC Catalogue number is of umbonal-ventral sulcus). AT313) Mr. N. Rowe is responsible for the photograph shown Length (mm) Height (mm) Ratio (L/H) in this communication. 6.3 4.2 1.50 9.3 5.7 1.49 11.9 6.8 1.60 Literature Cited 12.3 7.8 1.57 ; 12.6 8.1 1.56 Turner, RutH Drxon 13.0 7.9 1.65 1954. The family Pholadidae in the Western Atlantic and Eastern Pacific. Part I — Pholadinae. Johnsonia 3 (33): 1-63; plts. 1-34 Vol. 14; No. 1 THE VELIGER Page 33 New Pacific Northwest Neptuneas (Mollusca : Gastropoda : Neptuneidae) ALLYN G. SMITH California Academy of Sciences, San Francisco, California 94118 (3, Plates) DuRING THE LAST TEN YEARS or SO, specimens of large- sized carnivorous gastropods of the genus Neptunea have been accumulating from deep water off the coast of cent- ral California and the Pacific Northwest. The first men- tion of these is contained in a brief note by Robert R. Talmadge of Eureka, California, published in the Minutes of the Conchological Club of Southern California (John Q. Burch, ed.), no. 90, page 5, May, 1949. Mr. Tal- madge mentions 3 species of Neptunea brought in by commercial otter-trawl fishermen from off Humboldt Bay in depths down to 165 fathoms, including one con- sidered to be similar to N. pribiloffensis (Dall, 1919). Study of the first series of these shells obtained by Mr. Talmadge, comparison with the fine series of Neptuneas in the mollusk collection of the United States National Museum, and the subsequent availability of a consider- able number of additional specimens from off Humboldt Bay and other more northern localities have left no doubt about the novelty of this large, fairly common species. Neptunea humboldtiana A. G. Smith, spec. nov. (Figures J to 4 and 5 to 13) General Diagnosis: This light-colored, relatively short- spired Neptunea attains a large size for the genus and is characterized in the adult stage particularly by rounded later postnuclear whorls, deep sutures, and a tumid body- whorl; young shells have straight or somewhat sloping early whorls. The number of postnuclear whorls normally is 43 or 5; the canal is short. The outer lip flares widely on many adults and there is a tendency for a prominent secondary lip-flange to develop with age. Sculpture on the early postnuclear whorls consists of a few brownish col- ored fairly strong spiral cords, with or without finer intercalaries between them. The body-whorl of adult shells may be spirally lirate with weak spiral cords and inter- calaries, or may be entirely smooth. The species occurs most commonly in a general area roughly bounded on the south by Humboldt Bay, California, and on the north by La Perouse Bank off Cape Flattery, Washington, in depths ranging from 100 to 250 fathoms. It is related to N. pribi- loffensis, which lives farther to the north with a range south to Queen Charlotte Sound, British Columbia. Type Series: Twenty specimens, all with contained ani- mals, trawled in 120 fathoms off Redding Rock, Hum- boldt County, California (the type locality) by the M/V St. Joseph, 19 January 1960, received through the cour- tesy of Messrs. E. G. Gunderson, Tom Jow, and Jim Thomas of the California Department of Fish and Game. Holotype: A representative mature shell from the type series measuring: length, 132.1 mm; maximum diameter, 87.8 mm; length of aperture and canal, 83.7 mm; width of aperture, 55.5 mm. The apical angle is about 70°. It has been placed in the California Academy of Sciences Department of Geology (CASG) Type Collection, no. 13637. The animal, preserved in alcohol, is deposited in the California Academy of Sciences Department of In- vertebrate Zoology (CASIZ) Type Series, no. 418. The shell (Figure /) is large, whitish, thin textured, with a tumid body-whorl, well-impressed sutures, a spire slightly shorter than the rest of the shell, and a short canal bent somewhat to the left but not appreciably to the rear. The aperture is capacious, subovate, light orange- yellow inside, with a widely flaring outer lip having a final growth stage extending well beyond a prominent earlier one seen from the inside. The inner lip has a heavy wash of callus appressed to the somewhat sinuate colum- ella; there is no marked siphonal fasciole. The first 3 postnuclear whorls are nearly straight-sided; the penulti- mate and body whorls are rounded. The nuclear tip is broken off, the total number of postnuclear whorls being 52. Sculpture consists, on the first 2 postnuclear whorls, of 2 prominent spiral cords, the upper one near the whorl Page 34 periphery, the lower near the suture. The third postnuc- lear whorl has a nearly straight, sloping shoulder above the upper spiral cord; 3 faint intercalary riblets begin to show as this whorl increases in size. The 2 earlier heavy spiral cords become weaker on the penultimate whorl and fade out completely on the body-whorl, which is smooth except for a series of closely-spaced, subobsolete spiral lirae and the fine, irregular growth-ridges that show as an overlapping series of shell layers under a magnification of 10 (Figure 5). The shell has a dull finish; there are no vestiges of a periostracum. Paratypes: The remaining 19 specimens from the type locality are so designated. In addition, specimens from other than the exact type locality are also designated as paratypes as these have been collected within the known range of the species, have been studied in detail, and have contributed significantly to a knowledge of it. Paratypes have been distributed among several public museums and THE VELIGER Vol. 14; No. 1 institutions maintaining type collections (including the California Academy of Sciences) ; several have been sent to private collectors, who have cooperated in supplying specimens for review. Geographical Range; Specimens Examined: Based on an analysis of more than 100 specimens of all ages (ex- cept the nuclear stage), the range of Neptunea humboldt- iana extends from off the Farallons, central California, to an area 40 miles off Point Estevan, central Vancouver Island, British Columbia, Canada, in depths ranging from 50 to 800 fathoms. A single, live-collected adult may have come from as far north as the southern end of Hecate Strait, the collection data being uncertain as to specific locality. For purposes of discussion, the material at hand, preserved both dry and in alcohol, has been combined into 6 fairly homogeneous groups, as shown in Table 1. In addition to the material analyzed in Table 1, 5 adult and 6 juvenile shells from a series of 36 from 225 fathoms Table 1 Distribution and Numbers of Specimens Numbers of Specimens Po Measured § a a8 @ A - ba aie Bf GS Oo aS ocality < ) B A 50 Off the Farallones and Bodega 1 2 3 Head, California B 50-120 Off Humboldt Bar, Humboldt 9 2 11 Bay, California Cc 150-250 Off Humboldt Bay, California 26 18 44 (Redding Rock, Patrick’s Point, etc.) D 50-225 SW of the mouth of the Colum- 4 9 13 bia River, northern Oregon E 300-800 SW of the mouth of the Colum- 4 10 14 bia River, northern Oregon F 50-150 Vicinity of La Perouse Bank, 9 10 19 Washington, to Point Estevan, British Columbia Total specimens: 53 51 104 Plate Explanation Neptunea humboldtiana A. G. Smith, spec. nov. Figure 7: Holotype. California Academy of Sciences Geology Type Collection, no. 13637. Apertural view. Length, 132.1 mm; maximum diameter, 87.8 mm; 5? whorls. Figure 2: Adult shell lacking major spiral cords but having many closely-spaced spiral lirations. Paratype. Walter J. Eyerdam Collec- tion. Rear view. Length 131.7 mm Figure 3: Adult shell with outer lip doubled. Paratype, CASG Type Collection, no. 13638. Length, 127.5 mm. Apertural view. Figure 4: Apertural view of another adult shell with unworn sculp- ture and a complete nuclear whorl. Paratype, CASG Type Collec- tion, no. 13640. Length, 132.7 mm. Tue VE .icER, Vol. 14, No. 1 [A. G. Smiru] Figures ] to 4 Figure 3 Vol. 14; No. 1 off Brookings, Oregon, and 13 shells from a series of 150 from 100 to 200 fathoms off Humboldt Bay, obtained by Mr. Ralph Ferguson from commercial fishermen, have been studied and returned to him. Nearly half of the specimens of Neptunea humboldtiana have been trawled by fishermen working the area off Humboldt Bay for various species of sole (Group C, Table 1). This is the area selected as the type locality where shells generally are of large size and well developed when adult. However, it is obvious from a series trawled by the R/V N. B. Scofield, operated by the California Depart- ment of Fish and Game in fisheries investigations, that the species does occur in shallower water in the same area (Group B, Table 1), although adult shells are somewhat smaller. Two small specimens that can be identified properly as Neptunea humboldtiana have been taken as far south as the Farallons, about 20 miles off the central California coast opposite San Francisco Bay; another was dredged in 300 fathoms on green mud NNW of Bodega Head by the USS Albatross. The species did not turn up in the trawl- ing operations of the R/V N. B. Scofield off the coast of Mendocino County, although Mr. Talmadge reports it as having been collected off Fort Bragg; it was not en- countered until the Scofield reached the vicinity of Hum- boldt Bar in Humboldt County. Consequently, the Far- allon area may not represent the normal southern end of the range of the species. Except for the series of shells obtamed by Mr. Ferguson from off Brookings, Oregon, and others in the Talmadge Collection from 150 fathoms off Cape Arago and off Yaquina Bay in central Oregon, the next sizable group of specimens at hand comes from an area to the southwest of the mouth of the Columbia River, northern Oregon, in depths of 50 to 800 fathoms. These were collected by the United States Bureau of Fisheries, A. E. C. Project, using R/V Commando, with one lot obtained by the R/V John N. Cobb; most were live-taken and have been preserved in alcohol with the contained animals (CASIZ Collec- tion). This series of shells divides about equally between those from depths of 50 to 225 fathoms (Group D, Table 1) and those from 300 to 800 fathoms (Group E, Table 1), the latter from depths far exceeding any attained so far by West Coast commercial trawlers. The Neptuneas obtained by the Commando in this area also include a small series of juvenile specimens close to, or conspecific with, Neptunea stilesi A. G. Smith, 1966, and 2 small series of N. amianta (Dall, 1890). Contrary to the situa- tion off the Humboldt Bar, shells from deeper water off the mouth of the Columbia River are smaller in size. The northern part of the range of Neptunea humboldt- iana is in the vicinity of La Perouse Bank, about 40 miles THE VELIGER Page 35 off Cape Flattery, Washington. This is the general area worked by commercial trawlers operating out of Belling- ham, Puget Sound, Washington, from whom shells have been obtained through cooperation with Walter J. Eyer- dam of Seattle and the late Everett C. Stiles of Belling- ham. Adult specimens are not appreciably different in size from those living farther south. Except for a single shell said to have come from the southern end of Hecate Strait, the northernmost record for the species is based on an adult, typical specimen taken in 75 fathoms off Point Estevan, central Vancouver Island, by Karl W. Kenyon of the United States Fish and Wildlife Service (Paratype, CASG Type Collection, no. 13638). Individual Variation: For purposes of comparison, meas- urements and notes were recorded for a total of 53 more or less perfect adult shells of Neptunea humboldtiana. These consisted of a count of the total remaining postnuc- lear whorls to the nearest + volution; and the over-all shell length, maximum diameter, maximum length of the aperture and canal measured directly (7. e., not parallel to the shell axis), and the maximum width of the aper- ture taken from the outside surface of the outer lip to the edge of the wash of callus forming the inner lip. Because many adult shells had the outer lip broken or damaged to the extent that some of the measurements would be inaccurate, such shells were not measured. Likewise, dimensions of juveniles and subadults were not taken, as these would not provide additional significant data. A summary of the variation between various meas- urements by groups in ‘Table 1 is given in Table 2. The longest adult shell at hand (135.7 mm) is in the type lot from 120 fathoms off Redding Rock, Humboldt Coun- ty, California (Paratype, CASG Type Collection, no. 13639; animal in CASIZ ‘Type Series, no. 419). The longest known shell (144mm) is in the Talmadge Col- lection. The shortest adult shell (72.7 mm) comes from 325 fathoms off the mouth of the Columbia River, north- ern Oregon (Paratype, shell and animal, CASIZ Type Series, no. 420). Number of Whorls: The thinness of the shell structure of Neptunea humboldtiana is notable. For their size, no other Neptuneas from the West Coast of North America are nearly as light in weight. Thus, the shells are broken easily, especially if they have not developed appreciably thickened outer lips. This factor also contributes to the loss of the nuclear tip and one or more of the early postnuclear whorls, making an accurate whorl count dif ficult to obtain. Only 2 of all adult specimens examined retain perfect, unworm nuclear whorls (Figure 4). These are 2 in number, smooth, erect, nearly straight-sided, Page 36 THE VELIGER Vol. 14; No. 1 white, and somewhat chalky (Figures 7, 8). The postnuc- lear whorls on adult shells range from about 4 to 64; the most frequent number is 42 for 10 shells, followed by 5 whorls for 7, and 44, 44 and 54 on each of 6 shells. Only 3 of the total of 52 adults have 6 or more postnuclear whorls. Outer Lip Characteristics: Neptunea humboldtiana is remarkable for its globose body-whorl and its capacious aperture. The latter is enlarged by a tendency for the animal to develop a widely flared outer lip on reaching maturity and then, as it grows older, to increase the thickness of the outer lip and the canal by adding new shell layers. More remarkable, however, is the further tendency to develop a complete new second, separated outer lip flange (Figure 3). Out of the total of 52 adult shells available, 13 have the outer lip doubled in this manner, occasionally with an accompanying doubling of the tip of the canal. A thickening or doubling of the canal shell layers often creates a narrow but well-devel- oped siphonal fasciole. In older shells, also, there is often a thickening of the inner lip making the peritreme com- plete, and occasionally forming a small lip-notch at the top of the aperture. Canal: This is quite short compared with the rest of the shell in all adults. There is some variation in configura- tion, those on some shells being straight while on others they are bent slightly to the left or to the rear, or both. Sculptural Variation: The major spiral cords on all shells are more keel-like on the early postnuclear whorls (Fig- ure 6), becoming lower and more rounded on the later whorls, and often disappearing completely on the body- whorl. On many shells the major spirals are widely spaced and range from pinkish brown to dark brown in color. contrasting with the whitish or extremely light brownish ground color of the rest of the shells. The variation in spiral sculpture on adult shells can be described by re- ferring to 3 general types that differ in the numbers and strength of the intercalary lirations. In one type the major spirals are 2 in number on the first and second postnuc- lear whorls, with a weak third below the other 2 develop- ing on the third postnuclear whorl; the penultimate whorl has 3 well-marked spirals below the upper, and 2 even weaker ones below the lower; there are 2 and sometimes 3 faint intercalaries between and below the major spirals. The body-whorl has about 12 brown-colored major spirals with indications of some faint intercalaries between them. A second type of sculpture has about the same general aspect as the first, but with 4 to 6 rapidly developing, strong intercalaries between the major spirals. To the unaided eye, shells with this type of sculpture are notice- ably spirally lirate all over. A third, less frequently seen type is represented by 2 shells from the northern end of the range, in which the major spirals are much less evi- dent but with many, closely-spaced, strong spiral lirations covering the entire surfaces of the later postnuclear and body whorls (Figure 2). The Animal: Living animals of Neptunea humboldtiana have been observed by Mr. Talmadge, who has kindly permitted me to use his detailed notes. He says the body of the animal has a pale greenish-cream color heavily maculated with small, irregular, dark-brown blotches, which decrease in both number and size toward the edge of the foot. The tentacles and siphon are maculated also, the sole of the foot having a light tan or orange tint when seen crawling on a glass sheet (animals in alcohol retain some of the orange-yellow color and the dark macula- tions). The shell is carried well back over the tail, ex- posing the forward part of the body, head, and the broadly tapering tentacles during locomotion (Figure 12). The operculum is on the right side of the extended body and may be wholly or partially covered by the shell. Plate Explanation Neptunea humboldtiana A. G. Smith, spec. nov. Figure 5: Enlarged view of incremental sculpture of holotype (Figure 7) , showing overlapping series of shell layers. Figure 6: Apertural views of three juvenile paratypes. CASG Type Collection, nos. 13643 - 13645. Lengths (from left), 25.9, 30.4, and 51.2 mm respectively. Figure 7: Enlarged back view of nuclear whorl of paratype shown in Figure 4. Length, nuclear whorls only, 3.7 mm Figure 8: Enlarged front view of a complete nuclear whorl on another adult shell. Paratype, CASG Type Collection, no. 13641. Length, nuclear whorls only, 4.3 mm. Figure 9: Section of radula from animal in type lot. Central tooth with 2 cusps. California Academy of Sciences Invertebrate Zoology Type Series, paratype no. 418; slide no. 365. Width of radula, 1.6 mm. Figure 10: Same. Central tooth with 3 cusps. CASIZ Type Series, paratype no. 421; slide no. 366. Width, 1.5 mm. Figure 17: Same. Central tooth with 4 cusps. CASIZ Type Series, paratype no. 422; slide no. 367. Width, 1.5 mm. Figure 12: Shell from type locality with animal modeled in clay to show normal forward progression. White arrow indicates point of contact with substrate where shell area shows greatest wear in adult specimens. Figure 13: Dead shell with egg capsules. From 270 fathoms off Trinidad, Humboldt County, California. CASIZ Type Series, para- type no. 423. Length of shell, 76.3 mm. THE VELIGER, Vol. 14, No. 1 [A. G. Smiru] Figures 5 to 13 D ae Figure 5 Figure 7 Figure 12 Figure 13 THE VELIGER Page 37 Table 2 Measurements of Neptunea humboldtiana Vol. 14; No. 1 Item A B Cc Number of adult shells: 1 9 26 Depth (fathoms) : 300 50-120 150-250 Length (mm) : Range 83 98.1-124.6 101.8-135.7 Average 83 96.1 120.1 Length of aperture and canal (mm) : Range 50.6 60.5-74.5 66.1-83.7 Average 50.6 68.9 76.3 Maximum diameter (mm): Range 51.3 60.9-77.2 62.7-87.8 Average 51.3 69.9 77.3 Width of aperture (mm) : Range 29.0 34.1-50.2 33.6-55.6 Average 29.0 39.8 45.4 As can be seen in the illustration, an area of the body- whorl just outside the inner lip is in contact with the substrate during forward progression, wearing it smooth, and in some older shells thinning it to the extent of developing a hole clear through the shell. Operculum: There is little variation in configuration. The flexure noted on the operculum of the holotype is a consistent feature. The curving lines of growth gener- ally are strong, beginning with the nucleus at the lower end; some opercula have faint longitudinal striae spread- ing upward from the nucleus. Radula: This is typical for the genus. The variation is mainly in the number of denticles on the central tooth, which ranges from 2 to 4 (Figures 9 to 11). The radulae with 2 and 3 denticles on the central tooth, as illustrated here, were both from females from the type lot with about the same sized shells. Comparison with the radulae of other West American Neptuneas provide little, if any, basis for species differentiation. Sex: My determination of the sexes of available animals, combined with similar observations by Mr. Talmadge, indicate about an even distribution between males and females. No sexual dimorphism in the configuration and the sculpture of the shells is apparent. Habitat: According to information furnished Mr. Tal- madge by otter-trawl fishermen working the area in the D E F Over-all 4 4 9 53 50-225 325-800 50-150 50-800 96.8-119.0 72.7-97.4 110.1-132.7 TP TMS oi 106.6 84.1 121.3 111.8 65.3-78.7 45.6-60.1 64.3-83.2 45.6-83.7 70.9 52.8 77.6 72.6 60.4-78.5 44.8-55.3 66.2-85.7 44.8-87.8 70.7 49.6 79.5 73.2 38.0-45.0 24.4-32.8 33.7-48.6 24.4-55.6 40.2 27.7 44.1 42.2 general vicinity of the type locality off Humboldt Bay between Trinidad and Redding Rock, there is a more or less gentle slope to the bottom starting with a depth of 25 fathoms down to more than 300 fathoms — the slope paralleling a line 335° - 340° True. In the shallower depths the bottom chiefly is gray sand, which merges into gray or green muddy sand, then into sandy mud, and finally into nearly pure mud below the 200 fathom line. Most specimens of Neptunea humboldtiana have been trawled in 100 to 150 fathoms where the substrate is a combination of mud and sand. Bottom conditions toward the northern end of the range are not known to me. Behavior: Living snails obtained by Mr. Talmadge soon after they were brought in by the fishermen became active when placed in a 5-gallon capacity plastic bucket of aerated seawater. The amount of light (daylight, artificial light, or complete darkness) did not inhibit activity to any observable extent. Movements above the water to create distinct shadow patterns had no effect, but rapid movement of a hand under water inside the bucket caused the animals to retract partially. Unfortunately, the snails did not remain active much more than 3 days, probably due to a lack of good aquarium conditions, including adequate control of temperature within the limits to which they were accustomed. Eggs and Egg Capsules: Mr. Talmadge records the receipt of egg masses with capsules containing fresh em- Page 38 bryos in late September. Those obtained later in the year were open along the lower edge, indicating the eggs had hatched. The egg capsule is fibrous, nearly spherical, smooth, doubly concave, and measures 5 to 6 mm in dia- meter, with a thickness of about 2mm. Capsules are laid attached to each other in a slightly overlapping, rising spiral, each spiral string being attached to a lower one. Unhatched capsules contained 3 to 5 yellow-colored em- bryos approximately 1.5 mm in diameter as seen through the capsule wall. Capsules or masses of them may be attached to other living Neptunea shells, to dead shells occupied by hermit crabs (Figure /3,) or to consolidated lumps of mud on the sea bottom. Freshly hatched young have not yet been collected. Associated Invertebrates: The most common inverte- brate associated with Neptunea humboldtiana in the Humboldt Bay area is an unidentified pink sea anemone having a base 25 to 40 mm in diameter, a short column, and short tentacles. A single Neptunea shell may have 3 or 4 of these attached anemones, which undoubtedly live under commensal conditions. The same or similar ane- mones were found attached to living snails collected by the R/V Commando off the mouth of the Columbia River. Mr. Talmadge reports 2 specimens of Crepidula orbiculata Dall, 1919 were attached to shells collected alive in 200 fathoms off Trinidad Head. Small barnacles (Balanus hesperius Pilsbry), encrusting bryozoans and other sessile types of invertebrates, often are attached to dead shells, but live snails evidently are capable of keep- ing their shells clean of such organisms except for the sea anemones. Food: This is not yet known; no detailed analysis of the gut contents of animals collected alive has been attempted. Because the habitat of Neptunea humboldtiana also sup- ports a sizeable fauna of mollusks (both gastropods and bivalves) and other invertebrates, it may reasonably be assumed that it preys on some or all of these for its food. Comparison with Other Species: Species of Neptunea that occur within the geographical range of N. humboldt- tana include N. tabulata (Baird, 1863), N. lyrata (Gme- lin, 1791), N. phoenicia (Dall, 1891), N. smirnia (Dall, 1919), N. stiles: A. G. Smith, 1968, and N. amianta (Dall, 1890). Toward the northern end of its range in the vicinity of La Perouse Bank, Washington, at least one species of Beringius (B. eyerdami A. G. Smith, 1959) occurs also. Undoubtedly, the nearest relative is Neptunea pribil- offensis (Dall, 1919), and some may prefer to consider N. humboldtiana a subspecies of it. I have given it speci- fic rank, however, as there are at least 2 factors in favor THE VELIGER Vol. 14; No. 1 of such ranking. One is the apparent lack of overlap in the ranges of the 2 taxa based on present collecting data. The southern end of the range of N. pribiloffensis is re- ported as being the Queen Charlotte Islands, British Co- lumbia (Dati, 1921: 97); the northernmost verified record for N. humboldtiana off the central part of Van- couver Island is 300 to 400 miles south of the Queen Charlottes. The other factor is the greater number of postnuclear whorls of the former species compared with the latter, as indicated by the following figures: Numbers of Postnuclear Whorls N. pribiloffensis (13 adults) (52 adults) Range 54-7 Most frequent 63 Average 64 aa a N. humboldtiana + we Even allowing for the fact that the shells of N. pribiloff- ensis are somewhat more solid, with the early postnuclear whorls less subject to breakage, a difference of about 2 whorls between the two species is substantial. In addi- tion, comparison on the basis of other criteria shows that N. humboldtiana has: a. much deeper sutures b. much weaker spiral sculpture, the major spiral cords as well as the intercalary spiral lirations being less prominent or completely obliterated on the body- whorl c. more of a tendency toward a widely flaring outer lip in adult shells d. an unusual tendency for the outer lip to be doubled after reaching maturity, resulting in the develop- ment of an additional, separated lip flange. Except for the deeper sutures, adult shells of the two species have about the same size-range and general con- figuration. While discussing Neptunea pribiloffensis, it is pertinent to mention the important study of the genus Neptunea by A. N. Gottxov (1963), which includes 2 illustrations of shells identified as this species on plate XXI, figures a-b. These shells, which have straight-sided postnuclear whorls with a prominent spiral keel at their peripheries, are not at all similar to specimens in the collection of the California Academy of Sciences from Alaska and Bering Sea. California Academy specimens agree much more Vol. 14; No. 1 closely with the shell Golikov illustrates on his plate XIX, figure 1, which I believe to be incorrectly identified as N. amianta (misspelled “aminata’). The latter species is well illustrated by Dati (1890: 321; plt. 3, fig. 10); it has quite a different shell. Compared with what appear to be identified correctly as Neptunea amianta, typical mature shells of N. hum- boldtiana are nearly twice the size in both length and maximum diameter, show less sculpture on the body- whorl, and generally have weaker major spiral cords on the early postnuclear whorls. Neptunea amianta is thin- shelled, usually has a simple, unflared outer lip, and lives in deeper water. Based on 12 lots comprising 43 specimens of N. amzanta in the California Academy col- lection, the over-all depth range is 100 to 1000+ fathoms, with 31 specimens dredged from depths of 300 fathoms or more and only 12 from 250 fathoms or less. Thus, the benthic ranges of the two species overlap considerably. While adult shells of N. humboldtiana may be differenti- ated easily from N. amianta on account of the compara- tively larger size, this may not always be true. The largest specimen of the latter species in the California Academy collection, taken in 400 fathoms off the coast of central California (CASG no. 33050), is 83 mm long, although all other adult shells are much shorter. The length range of 4 mature specimens of N. humboldtiana from 325 to 800 fathoms off the mouth of the Columbia River (CAS- IZ collection) is 72.7 to 97.4 mm; the average is 84.1 mm. Young shells of N. humboldtiana superficially are much like older shells of N. amianta, making firm identification difficult; the latter species has a higher whorl count for shells of approximately the same size, however. Many California Academy specimens of N. amianta have rem- nants of a well-developed, greenish-brown, rather thin, rough coating of a species of hydractinian. This resembles a periostracum and tends to peel away from the shell when dry. Adult specimens of N. humboldtiana are al- most always completely devoid of a periostracum which, if present at all, is thin, almost colorless, occurs only here and there on some specimens, and is easily over- looked; even on young shells a periostracum is not a prominent feature. Neptunea humboldtiana is not at all closely related to the heavily ribbed N. lyrata, which ranges south into Puget Sound, Washington; to the much less common N. smirnia, which is smooth, light or pinkish brown in color and which occurs in the same area as N. humboldtiana; or to the dark-brown N. phoenicia, which has an olivace- ous periostracum and a sculpture of rather fine spiral cords. From N. stilesi it differs principally in the more rounded whorls and deeper sutures. The turrited N. tabu- lata has a shell with an entirely different aspect altogether. THE VELIGER Page 39 A second series of Neptuneas supplied by Mr. Stiles differs in a number of specific characters from other de- scribed species and comes from an area considerably north of the range of Neptunea humboldtiana. Neptunea meridionalis A. G. Smith, spec. nov. (Figures /4 to 20) General Diagnosis: Shells fairly large, white, with an a- cute spire slightly longer than half the total length. The early postnuclear whorls are nearly straight-sided, the later ones rounded and set off by well impressed sutures. Aperture capacious, usually white inside, with a flaring lip when adult (rarely doubled). The canal is short and twisted slightly to the left and to the rear. Sculpture con- sists of many fairly prominent spiral lirations between which are one or more weak to strong intercalaries. All of the shells at hand are light weight in texture and have been trawled by commercial fishermen operating out of Bellingham, Washington, in an area extending along the inside of the Queen Charlotte Islands to the southern end of Hecate Strait, British Columbia, in depths of about 100 fathoms. Description of the Holotype: Shell a large adult collec- ted alive, of rather thin texture, with 7 postnuclear whorls, the nuclear whorls missing (Figure 14). Color white with vestiges of a thin, yellowish periostracum. The acute spire has an angle of 59° and is a little longer than the rest of the shell. The first 4 postnuclear whorls are approximate- ly straight-sided, the last 3, especially the penultimate and body-whorls, being rounded with deep sutures. The aper- ture is large, white, porcellaneous inside, with a widely reflexed, slightly sinuous outer lip and an inner lip con- sisting of an appressed, thin wash of callus. The columella is straight, terminating in a short, nearly straight canal that is only very slightly bent to the right and to the rear. There is a moderately impressed siphonal fasciole. Fairly prominent spiral lirations occur on all postnuc- lear whorls. There are 3 on the first (one is sutural), 2 each on the second, third and fourth, 5 to 6 on the fifth, 8 to 9 on the penultimate, 13 on the body whorl, and 8 to 9 on the canal. On all whorls except the first, the up- permost lirations are positioned well below the sutures. There are 2 to 3 intercalaries (some stronger than others) between the more prominent spirals but in the downward- slanting spaces between the sutures and the uppermost prominent spirals there may be as many as 8 to 10 weaker spirals on the later postnuclear whorls. The microsculp- ture consists of rough, closely-spaced growth ridges (Fig- Page 40 ure 17). The operculum is typical for the genus, with the usual curving flexure down the median line. Measurements are: length, 126.5 mm; length of aper- ture and canal, 71.9mm; approximate length of canal only, 17 mm; maximum diameter, 72.7 mm. Type Locality: Hecate Strait, off the Queen Charlotte Islands, British Columbia, Canada, in about 90 fathoms. Type Material: Holotype deposited in the California Academy of Sciences Geology Type Collection, no. 13647. A total of 19 other shells, of which 8 are adults and 11 are subadults or juveniles, and which were collected in the same general area, are designated as paratypes and are deposited in various institutions maintaining mollus- can type repositories. Remarks: Neptunea meridionalis is a large, handsome, white species, collected so far only in the vicinity of Hecate Strait. According to Stiles, this is about as far north as the Bellingham trawlers operate. For this reason, there- fore, the northern end of its range has not been deter- mined; its southern end apparently does not extend as far as the center of the coast of Vancouver Island, which marks the northern end of the range of Neptunea hum- boldtiana. Of the 20 shells available, 8 have complete nuclear whorls, which is a relatively high number for such a thin- shelled Neptunea. The nuclear whorls are 2 to 24 in number, somewhat rounded, smooth and porcellaneous (Figure 16). The lirate sculpture of the postnuclear whorls is an abrupt rather than a gradual development. Flaring of the outer lip is a feature of the species. In one shell the outer lip is doubled (Figure 78) in a manner that is of fairly frequent occurrence in Neptunea hum- boldtiana. THE VELIGER Vol. 14; No. 1 Shell measurements are as follows: Average of Dimension Range 8 adults Length (mm) 102.1-129.7 122.0 Length of aperture and canal (mm) 61.6- 78.4 69.3 Maximum diameter (mm) 59.8- 77.6 69.2 Apical angle (°) 56-67 61 Number of postnuclear whorls 6-7 62+ Several animals of this species were obtained by Mr. Stiles, but unfortunately none of them was associated with a corresponding shell. These have been deposited in the California Academy of Sciences Invertebrate Type Series, nos. 424 to 427, inclusive. As preserved in alcohol, some are uniformly yellowish-white or light orange-yellow with no darker markings on the mantle or the foot; others have a few dark-colored markings on the mantle. Radulae of 2 animals were extracted and mounted (CASIZ Type Series nos. 424, 425; slide nos. 368, 369). These show slight variations in the configuration of the central teeth, which, in one instance, has 3 denticles of unequal size (Figure 79), whereas in another the denticles are about equal in size with a tiny, incipient fourth denticle on the outside shoulder of the central tooth (Figure 20). The lateral teeth are typical of the genus. Relationships: Neptunea meridionalis needs to be com- pared with 3 Pacific Northwest species — N. lyrata, N. pribiloffensis, and N. humboldtiana — and with the Jap- anese species N. intersculpta Sowerby, 1899, as all of these appear to be more or less related. While N. lyrata has about the same long-spired shape, adult shells are much heavier in texture and the fewer and more prominent Plate Explanation Neptunea meridionalis A. G. Smith, spec. nov. Figure 14: Holotype, CASG Type Collection no. 13647. Apertural view. Length, 126.5 mm; maximum diameter, 72.7 mm; 7 whorls. Figure 15: Rear view of adult shell with weaker spiral lirations. Paratype, CASG Type Collection, no. 13650. Length, 119.7 mm; maximum diameter, 66.5 mm; 7 whorls. Figure 16: Enlarged view of nuclear whorls of juvenile shell, with first 2 postnuclear whorls also; shows the abrupt change from smooth to lirate sculpture. Length, nuclear whorls only, 4.5mm. Paratype, CASG Type Collection, no. 13648. Figure 17: Enlarged view of incremental sculpture of the holotype (Figure 14) showing lines of growth and both strong and weak spiral lirations. Figure 18: Apertural view of adult shell with aperture doubled and with heavier spiral lirations. Paratype, CASG Type Collection, no. 13649. Length, 119.4 mm; maximum diameter. 74.7 mm; 62 whorls. Figure 19: Enlarged view of section of radula with 3 denticles of unequal size on the central tooth. Width of radula, 1.7 mm. CASIZ Type Series, paratype (animal only), no. 424; slide no. 368. Figure 20: Same. Radula from another animal with 3 central tooth denticles of about equal size and a fourth incipient denticle on the shoulder at one side. Width of radula, 1.5mm. CASIZ Type Series, paratype (animal only), no. 425; slide no. 369. Tue VE.icER, Vol. 14, No. 1 [A. G. SmiruH] Figures 14 to 20 Figure 14 Figure 20 Vol. 14; No. 1 spiral ribs are distinctly different sculpturally from the more frequent and less prominent spiral lirations of N. meridionalis. The ranges of these two species, however, undoubtedly overlap. Compared with N. pribiloffensis and N. humboldtiana, it has a distinctly longer-spired shell; the average number of postnuclear whorls (62+) is at least one-half more than for the former species (with 6}) and 2 more than for the latter (with 42+ ). In sculptural aspect N. meridionalis is much closer to N. pribiloffensis, but has the general appearance of being far more spirally lirate than is true for N. humboldtiana. It should be mentioned, however, that there are 2 shells of the latter species from the northern end of the range that are equally as spirally lirate, although the spirals are much weaker and not nearly as prominent. The relationship of N. intersculpta from Japan is not as close as with Pacific Northwest species, as this has a larger, heavier, yellowish or brownish-yellow, long-spired shell with alternating prominent and subobsolete spiral lirations. The extremely thin texture and pure white color of N. meridionalis set it apart from other species in the genus. ACKNOWLEDGMENTS Thanks and appreciation are due to my department asso- ciates, especially Dustin D. Chivers for painstaking work in extracting and mounting many Neptunea radulae and for assisting this study in a number of other ways, and Miss Dea Beach for her excellent radula photographs. I am grateful, also, to Mr. Maurice Giles, California Aca- demy scientific photographer, for the preparation of nega- THE VELIGER Page 41 tives and prints used for the remaining illustrations on the accompanying plates. Literature Cited Dati, WiLtt1am HEALEY 1890. _ Scientific results of explorations by the U.S. Fish Com- mission steamer Albatross. VII. Preliminary report on the col- lection of Mollusca and Brachiopoda obtained in 1887-88. Proc. U.S. Nat. Mus., 1889, 12 (773) : 219 - 362; plts. 5 - 14 (7 March 1890) 1921. Summary of the marine shellbearing mollusks of the northwest coast of America, from San Diego, California, to the Polar Sea, mostly contained in the collection of the United States National Museum, with illustrations of hitherto unfig- ured species. U.S. Nat. Mus. Bull. 112: i-iii + 1-217; plts. 1 - 22 (24 February 1921) 1925. _ Illustrations of unfigured types of shells in the collection of the United States National Museum. Proc. U.S. Nat. Mus. 66 (2554): 1-41; plts. 1 - 36 (22 September 1925) Goutkov, A. N. 1963. The gastropod mollusks of the genus Neptunea BoLTEN. Acad. Sci. U.S.S.R, Zool. Inst., n.s. no. 85 (Fauna of the U. S.S.R., Mollusks, vol. 5, issue 1): 1-217; plts. 1-28; figs. 1-98 in text Moscow/Leningrad [in Russian] MacNEIL, Francis STEARNS 1957. | Cenozoic megafossils of northern Alaska. Wigs: Geol. Surv. Prof. Paper 294G: 99 - 126; plts. 11-17 SmirH, ALLYN GoopwIN 1968. A new Neptunea from the Pacific Northwest. The Veliger 11 (2): 117-120; plt. 14 (1 October 1968) TaLMADGE, RopErRT RAYMOND 1949. [Note (in litt.) on mollusks of Humboldt Bay and vicin- ity] In: Minutes Conch. Club. South. Calif. (J. QO. Burcu, ed.), no. 90, pp. 5-6 (May 1949) Page 42 THE VELIGER Vol. 14; No. 1 The Benthic Mollusca, Plicifusus, in California (Mollusca : Gastropoda ) ROBERT R. TALMADGE’ Eureka, California (1 Plate) MOLLUSCAN LITERATURE indicates that one species of the circumboreal benthic genus Plicifusus Dall, 1902, inhabits the Pacific Coast of America from the Bering Sea south to San Diego, California. My work with this species, P griseus (Dall, 1889) verifies portions of this range, as I have examined specimens of it from several localities well within the designated range, and a small series has been collected from northern California. It appears that there is a paucity of fossil records from the Pacific Coast of America, as I could locate only one from California. There are Japanese records of one species (and subspe- cies), but the evidence indicates that even in Japan the genus is poorly represented in the fossil fauna. In 1967, I collected a poorly preserved fossil specimen of a Plicifusus from the Pliocene Lower Wildcat Fauna in Humboldt County, California, and during 1969, I obtained a small series of a species which appears to be new to science, from the dragboat fishermen operating out of Humboldt Bay, California. Ecological data available on the better known P griseus and two new taxa are pre- sented here. Plicifusus Dall, 1902 Type, by OD: Fusus kroyeri Moller, 1842 (Latifusus) Dall, 1916 Type by OD: Chrysodomus griseus Dall, 1889 Plicifusus (Latifusus) griseus (Dall, 1889) 1889. Chrysodomus griseus Dall, Proc. U.S.N.M. 12: 332; pit. 5, fig. 6 « Field Associate, Department of Invertebrate Zoology, California Academy of Sciences 4 Oldroyd used the date 1877; it should be 1889 1921. Retifusus griseus Dall. U.S. N. M. Bull 112: 93 1927. Plicifusus (Latifusus) griseus Dall. OLpRoyp 2 (1): 210? 1931. Neptunea (Colus) grisea (Dall). Grant « GaLE, Mem. San Diego Soc. Nat. Hist. 1: 664 Type: In U.S.N.M., Washington, D.C. Type Locality: Off the Channel Islands, Santa Barbara, California. Geographical Distribution: Dati (1921) gave the range as from the Bering Sea in 27 fathoms south to San Diego, California, in 636 fathoms. Kren (1937) gives the range in degrees latitude: 33° to 60° N, with a midpoint of 46° N. BerNarD (1967) uses the same method but gives the range as from 32° to 60° N, and adds ‘80 - 200 fath- oms.’ I have obtained specimens from between 40°28’ to 42°00’ N (submerged Eel Canyon to California-Oregon boundary), taken from between 200 and 400 fathoms on a soft mud substrate. I examined a series taken off the Channel Islands on a soft mud substrate from between 400 to 600 fathoms, and a small set from 200 fathoms, also from a soft mud substrate off Uculet, on the west coast of Vancouver Island, British Columbia, Canada. I have been unable to note any geographical variations or sexual dimorphism. The shell characteristics appear to be very uniform throughout the range, as far as I can see. Plicifusus (Latifusus) indomitus Talmadge, spec. nov. (Figures 7, 2) Description: The single specimen is chiefly an interior mould, consisting of 34 whorls and measuring 26.6 mm in length and 18.6 mm in diameter. Both the apex and the siphonal canal are broken, but a projection of the shell indicates a specimen approximately 38 mm in length. Most of the original shell material was lost as the speci- men lay weathering amid the talus in which it was dis- Tue VE icER, Vol. 14, No. 1 [TaLmapcE] Figures 1 to 4 Plicifusus (Latifusus) indomitus Talmadge, spec. nov. Holotype; Pliocene Figure 1: Dorsal aspect Figure 2: Ventral aspect Plicifusus (Microfusus) obsoletus Talmadge, spec. nov. Holotype, Recent Figure 3: Dorsal aspect Figure 4: Ventral aspect photographs by California Academy of Sciences Vol. 14; No. 1 covered. However, observations made in the field and also on remains of the shell adhering to the mould in- dicate that there were about 12 rather strong axial ribs crossing the third and penultimate whorls, but the ribs were missing on the body whorl. Although the whorls are rounded, they are rather elongate and the suture is not sharply defined. There is a boring (naticid?) on the dorsal surface of the second whorl. Holotype: To be deposited in the Geology Type Collec- tion of the California Academy of Sciences, San Francis- co, California, where it will bear the CASTC no. 13651. The number on the figured holotype is only a Talmadge Collecting Locality number. Type Locality: The specimen was found amid the talus of a cliff on the west side of the Eel River, approximately 200 feet upstream (south) of the U.S. Highway 101 bridge between Scotia and Rio Dell, Humboldt County, California. This is in the lower Rio Dell Formation, Wildcat Group of Ocie (1953), but there are no recorded collecting stations at this site, neither by OcLE (op. cit.) nor Faustman (1964). All authorities agree that this is Lower Pliocene in age. Discussion: It is quite possible that this site was concealed by slides or overburden, and was not exposed until after the major flood of December 1964. The stratum is a hard, brittle mudstone that weathers into small angular frag- ments. These fragments fall from the nearly vertical cliff onto a narrow ledge by the edge of the river where they form a steeply sloping talus. This talus is washed away each winter by the normal high water and is replaced by falling fragments each spring and summer. Found in association with Plicifusus indomitus are Beringius arnoldi (Martin, 1914) and an undescribed fossil Bathybembix. I have seen no Recent Beringius from further south than the generalized Puget Sound region, and in that region they are usually taken in 100 fathoms or more of water. There is the Recent Bathybembix bairdii (Dall, 1889), living in excess of 300 fathoms off northern California, and 2 species of Plicifusus. One, P. griseus, lives on a soft mud substrate in as shallow a depth as 200 fathoms. As I have not seen the paper by Rivers, cited in GRANT & Gate, 1931, I cannot comment on the “?Pleistocene- Pliocene” Neptunea (Colus) grisea, nor am I familiar with the formations or fauna of the “Santa Monica Range.” However, P. indomitus has a more elongate shell than F griseus, and the axial ribs are fewer in number than in P griseus and do not extend down onto the body whorl. THE VELIGER Page 43 The name indomitus, Latin for “untamed,” refers to the condition of the Eel River on whose shores the speci- men was found. (Microfusus) Dall, 1916 Type by OD: Chrysodomus acutispiratus Sowerby "4, 1913 Plicifusus (Microfusus) obsoletus Talmadge, spec. nov. (Figures 3, 4) Description: The shell is small, spindle-shaped, very slen- der, with at least 7 rounded whorls, a sharply incised suture and a short siphonal canal. The axial sculpture consists of 19 to 21 rounded ribs which cover the spire and extend downward to the periphery of the body whorl. There is a spiral sculpture of a fine, thread-like cording, more noticeable on the spire and obsolete in the body whorl. The one operculum obtained was neptunid in char- acter. The shell is of a rich chestnut color with a tawny band at the suture. Holotype: The holotype, CASTC no. 13319, California Academy of Sciences, San Francisco, is 27 mm in length; it was obtained early in 1970 from the drag boat City of Eureka, which had been fishing in 450 fathoms between Trinidad, Humboldt County, California, and off the mouth of the Klamath River, Del Norte County, Cali- fornia (latitude, approximately 41°05’ N to 41°25’ N). The substrate was soft mud. Paratypes: Of 2 paratypes, one (no. 1) was taken in the submerged Eel Canyon (latitude 40°28’ N) on soft mud in 420 fathoms by the drag boat Mineo Brothers and is in the Talmadge collection, Eureka, California. Paratype no. 2 was taken with the holotype and will be deposited in the Los Angeles County Museum of Natural History, Los Angeles, California. There is an additional fragmentary specimen taken from somewhere near Trinidad, Hum- boldt County, California by the Sitka in about 400 fath- oms. Discussion: All of the specimens are nearly identical ia size, shape, sculpture, and coloration and all were ob- tained on a soft mud substrate, a characteristic also _ noted in the series of Plicifusus griseus. Perhaps the most complete collection of Plicifusus on the Pacific coast is that in the Department of Geology at Stanford Univer- sity. Here is preserved the Oldroyd collection with many Page 44 THE VELIGER Vol. 14; No. 1 of the specimens identified by Dall, who also described many of them. Of all the species noted, only P (Micro- fusus) brunneus (Dall, 1877) may be compared with P (M.) obsoletus. There is one specimen of P (M.) brun- neus in the Stanford collection, evidently fully adult, as the specimen compares favorably with P (M.) obsoletus in size, while the holotype of P (M.) brunneus is rather small. The specimens of P (M.) obsoletus have more axial ribs (19 to 21 as against a maximum of 14), more or less obsolete spiral sculpture, and a slightly shorter siphonal canal. The name obsoletus, Latin for ‘obsolete or lacking,’ alludes to the lack of strong spiral cording which is com- mon in the genus and subgenus. ACKNOWLEDGMENT I wish to express my appreciation to the many persons who assisted in this project. Dr. Leo G. Hertlein, Mr. Allyn G. Smith, Mr. Dustin Chivers and Mr. Barry Roth of the California Academy of Sciences searched into some of the lesser known literature, had photographs made of the type specimens, and in general assisted in many ways. Dr. A. Myra Keen of Stanford University opened the Oldroyd Collection so that direct comparisons could be made with specimens identified by Dall. Dr. Clyde E E. Roper of the United States National Museum made cer- tain key specimens available for study, and Dr. James H. McLean of the Los Angeles County Museum of Natural History made his series of photographs of the type speci- mens in the U. S. National Museum available to me. The men of the drag boat fleet, operating out of Humboldt Bay, California, saved specimen material and freely made available any ecological data that they had on depths, substrate, and locality from which the specimens were obtained. Literature Cited BERNARD, FRANK 1967. Prodrome for a distributional check-list and biblio- graphy of the Recent marine Mollusca of the West Coast of Canada. Fish. Res. Brd. Canada Tech. Reprt. 2: ii - xxiv-+ 1-261 Dai, WILLIAM HEALEY 1921. Summary of the marine shellbearing mollusks of the northwest coast of America, from San Diego, California, to the Polar Sea.... Bull. U. S. Nat. Mus. 112: 1 - 217; plts. 1-22 (24 February 1921) FAUSTMAN, WALTER FE. 1964. Paleontology of the Wildcat group at Scotia and Center- ville Beach, California. Univ. Calif. Publ. Geol. 41 (2) : 97 - 160; plts. 1-3 Grant, ULyssEs Simpson, IV « Hoyt RopNgey GALE 1931. Catalogue of the marine Pliocene and Pleistocene Mol- lusca of California and adjacent regions. San Diego Soc. Nat. Hist. Mem. 1: 1036 pp., 32 plts. (3 November 1931) KEEN, A. Myra 1937. An abridged checklist and bibliography of west Ameri- can marine Mollusca. Stanford Univ. Press, 87 pp.; 3 figs. Octe, BurpetTe A. 1953. Geology of Eel River Valley area, Humboldt County, California. Calif. Div. Mines Bull. 165 O.proyp, IpA SHEPARD 1927. The marine shells of the west coast of North America. 2 (1): 297 pp.; 22 plts. Stanford Univ. Press, Stanford, Calif. Vol. 14; No. 1 THE VELIGER Page 45 Observations on the Food and Feeding of some Vermivorous Conus on the Great Barrier Reef HELENE MARSH School of Biological Sciences, James Cook University of North Queensland, Townsville, Australia Zoology Department, University of Queensland, Brisbane, Australia I (2 Text figures) INTRODUCTION THE FEEDING MECHANISM of post-larval Conus is well documented (for references see KoHn, 1959, 1968). As far as is known, all species are carnivorous and possess a venom apparatus used primarily in the capture of prey. Koun (1959) has shown that three groups of species within the genus can be distinguished on the basis of their food. Most feed on marine worms, mainly poly- chaetes, while the second group feeds on fish and the third on other gastropods. Although details of the food of Conus from several parts of the Indo-Pacific are known (Koxwn 1956, 1959, 1960, 1966, 1968), little information is available on the diet of Conus on the Great Barrier Reef. Details of the feeding, food, and degree of dietary specialization for some of the most common intertidal ver- mivorous species are investigated in this study, as this information was considered basic to subsequent work on the effects of the venoms of these species. STUDY AREAS This report is based on field studies made at Lady Elliot Island and Low Isles. Lady Elliot Island (24°07’S and 152°45’ E) is a shingle cay situated at the southern ex- tremity of the Great Barrier Reef and about 40 miles from the Queensland mainland. Only populations of Conus which occur on the reef crest have been studied. The reef crest area is exposed at low tides except extreme low " Present Address: School of Biological Sciences, James Cook University of North Queensland, Townsville, Australia water neaps. Studies were made of specimens of Conus collected from the reef to the south-east, east and north of the island where the crest is conspicuous and easily de- fined. These areas are very flat and composed principally of shingle covered by algal turf. Distributed erratically over the crest are boulders and shallow sand-filled depres- sions. Low Isles (16°23’S and 145°34’ E) is approximately 7 miles off the North Queensland coast and about 20 miles shoreward of the outer Barrier Reefs. Several publications may be consulted to give details of the reef at Low Isles (e. g. STEPHENSON et al., 1931; STEPHENSON, ENDEAN & BENNETT, 1958). Specimens were collected from the reef on the south-east (see STEPHENSON, ENDEAN & BENNETT, op. cit.: 265, fig. 2, locality 31) at low water spring tides. The habitat was more complex than that described above at Lady Elliot Island because the area exposed at low tide included some living coral colonies on the seaward margin of the crest. METHODS Lady Elliot Island was visited twice in 1967 — from 23" February to 7* March and from 29" June to 5" July. Low Isles was visited from 22"¢ to 29" of August 1969. Specimens of the most common species of Conus were collected on day and night low tides, weather permitting, and placed in 10% formalin immediately after collection. The shell length of each specimen was measured to the nearest 0.5 mm with vernier calipers and the gut contents examined within 24 hours of collection. As polychaetes were the main prey items, indigestible setae and jaws permitted subsequent identification by referring to Day, Page 46 1967; Fauve, 1923, 1927; and Monro, 1931. References to the other pertinent literature used, such as species de- scriptions, are listed in the above monographs. Information theory may be used to derive numerical measures of prey species diversity and prey specificity. Following Koon (1966, 1968) SHANNON & WEAVER’S (1949) entropy (H) was used as a measure of prey species diversity. When all prey species are equally abundant H is a maximum of In N (N being the number of prey spe- cies identified). H is always non-negative and is zero when only one prey species is present. Redundancy (R) (SHANNON & WEAVER, Op. cit.) may be used as a direct measure of relative food specialization (H.S. Horn, un- published, cited by Kon, 1966). When each item in a diet is equally abundant R = 0. As the diet becomes in- creasingly specialised R approaches 1. The food species overlap index Ro (Horn, 1966) was used as a measure of prey species overlap. Ro varies from 0 when two predatory species have completely distinct diets to 1 when the diets are identical with respect to prey species composition and proportion. RESULTS (1) SPECIES COLLECTED Lady Elliot Island The following species were collected alive on the reef crest at Lady Elliot Island during the two trips in 1967: Conus aulicus Linnaeus, 1758 Conus catus Hwass in Bruguiére, 1792 Conus chaldeus Roding, 1798 Conus coronatus Gmelin, 1791 Conus ebraeus Linnaeus, 1758 Conus episcopus Hwass in Bruguiére, 1792 Conus flavidus Lamarck, 1810 Conus geographus Linnaeus, 1758 Conus imperialis Linnaeus, 1758 Conus lividus Hwass in Bruguiére, 1792 Conus marmoreus Linnaeus, 1758 Conus miliaris Hwass in Bruguiére, 1792 Conus musicus Hwass in Bruguiére, 1792 Conus omaria Hwass in Bruguiére, 1792 Conus rattus Hwass in Bruguiére, 1792 Conus sanguinolentus Quoy & Gaimard, 1834 Conus striatus Linnaeus, 1758 Conus terebra Born, 1780 Conus textile Linnaeus, 1758 Conus tulipa Linnaeus, 1758 Conus virgo Linnaeus, 1758 THE VELIGER Vol. 14; No. 1 Low Isles The following species were collected alive by the author on the reef crest at Low Isles during August 1969. Conus capitaneus Linnaeus, 1758 Conus chaldeus Roding, 1798 Conus coronatus Gmelin, 1791 Conus ebraeus Linnaeus, 1758 Conus emaciatus Reeve, 1849 Conus flavidus Lamarck, 1810 Conus frigidus Reeve, 1848 Conus lividus Hwass in Bruguiére, 1792 Conus marmoreus Linnaeus, 1758 Conus miliaris Hwass in Bruguiére, 1792 Conus musicus Hwass in Bruguiére, 1792 Conus sanguinolentus Quoy & Gaimard, 1834 Conus rattus Hwass in Bruguiére, 1792 For the purposes of this paper CERNoHORSKY (1965) has been followed in considering Conus lividus and C. san- guinolentus as separate species. KoHN (1959a) considers C. sanguinolentus to be synonymous with C. lividus. (2) SIZE AND SEX RATIOS Shell length was used as a measure of shell size. Infor- mation on the size and sex of the dissected specimens of the commoner species is summarised in Figures 1 and 2. These figures are not a measure of the relative abundance of the Conus species on the reef crest. Shell length of males and females does not differ at the 0.05 level of significance in any species tested at Lady Elliot Island or Low Isles (t tests). The sex ratio differs significantly from unity only for Conus sanguinolentus at Lady Elliot Island (X? test 0.001 < P < 0.05). (3) FEEDING OBSERVATIONS During dissection of Conus the position of food in the gut was noted, and as the time of collection was known approximate feeding times could be ascertained. KoHN (1959) showed that for the vermivore, C. abbreviatus Reeve, 1843, food started to move into the intestine after (on facing page —>) Figure 1 Length frequency distributions for Conus collected at Lady Elliot Island. Sample size, mean shell length + standard deviation are given for both sexes. For this February and July data are combined. Vol. 14; No. 1 THE VELIGER Page 47 | § ebruary July collections collections Con us chaldeus NSE 8 Aayfsas loz 149 9 : 26.7429 Conus ebraeus 1030S : 30.7+4.6 899 9 : 30.9+5.1 Conus coronatus 600: 18.6+5.1 8292 : 19.1+44.2 July data not available Conus miliaris sex data not available shell length: 20.55+3.9 Conus flavidus Hier CP 8 Bilseees) NOSIS S §33!4-E5:9 Conus sanguinolentus Sect 9 Fkas Gy 202 2 : 44.1412:12 12-14 15-17 1820 21-23 24-26 27-29 30-32 33-35 36-38 39-41 42-44 45-47 48-50 51-53 54-56 Length (mm) Page 48 THE VELIGER Vol. 14; No. 1 Conus chaldeus 1008S : 31.3+42.8 699 : 30.0413 5 0 30 25 20 Conus ebraeus 15 35d oS : 35.2464 2829 9 : 36.0+7.4 10 5 0 be a 525 Zz Conus flavidus 2938S : 38.2+8.0 312 2 : 38.9+8.5 Conus lividus 160 oS : 37.2+ 9.8 622 : 40.0+18.4 Conus sanguinolentus 198 oS : 39.5+10.8 1299 : 42.6+13.2 12-14 15-17 1820 21-23 24-26 27-29 30-32 33-35 36-38 39-41 42-44 45-47 48-50 51-53 54-56 Length (mm) Vol. 14; No. 1 THE VELIGER Page 49 Table 1 Percentage of Conus ebraeus which had food in the proboscis and oesophagus at different times of day. Low tide occurred at about the middle of each collecting period. Average times of sunset and sunrise for each collecting trip are indicated. Lady Elliot Island Lady Elliot Island Low Isles February-March June-July August Sunrise: 0540 Sunset: 1825 Sunrise: 0635 Sunset: 1710 Sunrise: 0631 Sunset: 1815 64 6a 6 u a a Be | a & aL & ro 33 33 Ba &o 2o &o 5 2 ge 50 ge 33 ge 25 =i?) QO a a 2 3} mM Time gS ae Ti ES a Tim ES 29 ZS &8 sar Ze We 2 28 Qk 0130-0300 41 2.4 0000-0200 10 40 0300-0500 17 29.4 0600-0900 61 39.3 0800-1000 19 68.4 1000-1200 19 36.8 0930-1230 50 18 1200-1500 28 32 1300-1500 14 0 2000-2300 22 46 Table 2 Percentage of Conus flavidus which had food in the proboscis and oesophagus at different times of day. Low tide occurred at about the middle of each collecting period. Average times of sunset and sunrise for each collecting trip are indicated. Lady Elliot Island Lady Elliot Island Low Isles February-March June-July August Sunrise: 0540 Sunset: 1825 Sunrise: 0635 Sunset: 1710 Sunrise: 0631 Sunset: 1815 5. B. Ep EE Ae fe Se 32 82 33 25 = &© i &6 eee gE 2 Bees Bo fs Bo Se SO) Ba) Time z ro 2s Time Z 3 w8 Time Z S es 0130-0500 95 16 0000-0400 23 34.8 0410-0240 9 22.2 0600-0915 61 262 ; 0800-1200 24 0 0930-1230 41 2.4 1200-1400 16 172-55 1300-1500 15 6.7 1500-1700 6 0 2000-2200 16 6.3 2200-2300 6 83.3 (<— on facing page) 1} hours in the oesophagus. After 3 hours faecal matter appeared in the rectum. Thus, food in the oesophagus Figure 2 and proboscis suggests recent feeding. Tables 1 and 2 Length frequency distributions for Conus collected at eee these data for C. ebraeus and C. flavidus, the Fon species for which most information is available. These data do not cover the full 24 hour period and are Sample size, mean shell length + standard deviation are given for both sexes. limited to low tide times. However, it can be seen from Page 50 Tables 1 and 2 that Conus flavidus appears to feed mainly at night while the C. ebraeus feeding time extends at least until mid-morning. In 2 cases collecting of C. ebrae- us before 0300 hours yielded very low returns. Collec- tions between midnight and dawn for both species pro- duced a higher percentage of food in the proboscis and oesophagus during winter than in summer which suggests that the onset of feeding activity may be linked to sunrise and sunset times. Although the capture of a prey worm by Conus was never observed, C. ebraeus and C. flavidus were often seen at night with proboscis extended and probing the algal turf which covers the crest area. Conus ebraeus and C. flavidus were each seen once while swallowing their prey, Palola siciliensis and Dasybranchus cadacus THE VELIGER Vol. 14; No. 1 respectively. In neither case was there any evidence of prey paralysis. On three occasions active non-paralysed prey was found in the oesophagus of Conus. Two speci- mens of live D. cadacus were removed each from a C. flavidus and a live P. siciliensis was removed from C. ebraeus. (4) FOOD Tables 3 and 4 show the food items identified from Conus collected at Lady Elliot Island and Low Isles re- spectively. All species fed exclusively on polychaetes ex- cept C. sanguinolentus which ate enteropneusts as well. Errant polychaetes of the families Eunicidae and Nereidae were the most important items in the diets of C. chaldeus, Table 3 Prey organisms consumed by the six most common species of vermivorous Conus on the reef crest at Lady Elliot Island. February- March and June-July data are combined. Prey organisms A Polychaetes Ampharetidae (1 species) Capitellidae Dasybranchus cadacus (Grube, 1846) other capitellids (1 species) Cirratulidae (1 species) Maldanidae Petaloproctus terricola Quatrefages, 1865 ' Axiothella australis Augner, 1914? Terebellidae Strebolosoma (2 species) Eunicidae Palola siciliensis Grube, 1840 Palola siciliensis Grube, 1840' Arabella irecolor (Montagu, 1804) Lysidice collaris Grube, 1870 Nereidae Perinereis (1 species) other nereids Phyllodocidae (1 species) unidentified annelids B_ Enteropneusts Ptychoderidae Ptychodera flava Eschscholtz, 1825 ' Total identified food Unidentified food Conus species . and number of individuals examined 3 3 6 ay 6 3 iS) 3 3 8 < 3 oS Ba Sa So 8m So Sr ge §8 83 48 58 f> S © S § aS ie oes os cade merccee Ba BO 58 8 § er Species 5 8 as BOE 0 6 ag ag Za A Lady Elliot Island Conus coronatus 1.1541 0.1676 4 18 ebraeus 0.3095 0.7768 4 67 flavidus 1.2178 0.4144 8 53 sanguinolentus 1.0334 0.0593 3 11 miliaris 0.6804 0.0183 2 19 B_ Low Isles ebraeus 0.8095 0.2809 3 17 Page 52 The indices of prey species overlap (Re), calculated for all pairings of the Lady Elliot Island species in Table 5, are presented in matrix form in Table 6. Table 6 The indices of prey species overlap Ro calculated for all pairings of five species of Conus at Lady Elliot Island. Conus ebraeus flavidus sanguinolentus miliaris eS 3 & = a S = es 6 S iS} 3 x -§ 2k & 3 3 2s 9 iS} as iT) 5 5 5 8 5 S S o ~~ 5 Of the species studied at Lady Elliot Island Conus flavidus had the most diverse diet as measured by both H and the number of prey species eaten. Conus ebraeus had the diet with the lowest diversity and highest redundancy at this locality. However, at Low Isles nereids comprised a greater proportion of the diet of C. ebraeus and its diet was both more diverse and less redundant than at Lady Elliot Island. Reference to Table 6 shows that the species which ate sedentary polychaetes, Conus flavidus and C. sanguino- lentus had little or no dietary overlap with any of the other species at Lady Elliot Island. In contrast, the spe- cies feeding on eunicids and nereids, C’. ebraeus, C. coron- atus and C’.. miliaris had fairly similar diets and the Res for the various pairings of these species were all greater than 0.6. DISCUSSION Gut-content analyses of 887 vermivorous Conus yielded 307 specimens of prey of which 265 were identified. All the Conus studied fed on polychaetes, C. sanguinolentus eating enteropneusts as well. Comparison of the food of Conus from Hawaii (KoHn, 1959), Ceylon (Konn, 1960), the Maldive and Chagos Islands (Koun, 1968) and the Great Barrier Reef shows that the diets of various species of Conus are remarkably constant. For example, Palola siciliensis is a major food item of C. ebrae- us at Hawaii, Maldive and Chagos Islands and at Lady Elliot Island. However, bioassay studies suggest that with- THE VELIGER Vol. 14; No. 1 in the vermivorous Conidae prey specificity is not reflected in venom specificity. Marsu (1970) found that the venoms of 5 species of Conus affected P. siciliensis even though it was a prey animal of only 3 of them. Field evidence shows that the prey of vermivorous Conus is not necessarily paralysed. As the capture of prey was not observed, it is not known whether, in these cases, the prey was stung. In the laboratory the stinging of prey is not essential to feeding in vermivorous cones (Koon, 1959; Marsu, 1970; SauNDERS & WOLFSON, 1961). Bioassay work (Marsu, 1970) to test the effect of the venom of C. chaldeus, C. ebraeus, C. flavidus, C. lividus and C’. miliaris on Palola siciliensis showed that the effect of the venom was to inhibit the polychaete’s re- sponse to stimulation and to render it incapable of normal progression rather than to paralyse it. Only the venom of C. lividus caused paralysis, but this was limited to a few segments in the region of injection. Koun (1966) presents evidence that for the genus Conus increased food specialization is associated with increased numbers of taxonomically and ecologically sym- patric species. Conus californicus Hinds, 1844, the only species of Conus occurring in southern California has a far more diverse (H = 2.82 and less redundant (R = 0.12) diet than do the species which occur on Hawaii and Maldive and Chagos coral reefs where there are large numbers of sympatric species of Conus. Twenty-one spe- cies of Conus were recorded from the reef crest at Lady Elliott Island and 13 from the crest at Low Isles. 'The diets of the vermivorous Conus from these areas were also characterised by low diversity and high redundancy com- pared with C. californicus. It is also notable that at Lady Elliot Island the 2 species with lowest prey species overlap, C’. flavidus and C. sanguinolentus had the most diverse and least redundant diets. Thus, species of Conus which co-occur and exploit the same set of resources are more specialised in diet than C. californicus. SUMMARY 1. Twenty-one species of Conus were collected from the reef crest at Lady Elliot Island and 13 species from the crest at Low Isles. 2. The size distribution and sex ratios of the most common vermivorous Conus were calculated. 3. Feeding was shown to take place mainly at night for Conus flavidus while Conus ebraeus appeared to feed at least until mid-morning. 4. Field evidence was obtained that the prey of vermi- vorous Conus is not always paralysed. 5. All the Conus studied fed exclusively on polychaetes Vol. 14; No. 1 THE VELIGER Page 53 except Conus sanguinolentus which ate enteropneusts as Horn, H. S. well. 1966. | Measurement of “overlap” in comparative ecological 6. The diets of the species studied were characterized by studies. Amer. Natural. 100: 419 - 424 low diversity and high redundancy. Koun, Aran Jacoss 1956. Piscivorous gastropods of the genus Conus. Proc. ACKNOWLEDGMENTS Thanks are due to Dr. A. J. Kohn for his helpful advice and his invaluable assistance in the identification of poly- chaetes. Drs. E Grassle, P. Mather, and M. C. Bleakly and Mrs. A. Alexander also assisted in the identification of prey animals. My supervisor, Mr. R. Kenny gave help- ful criticism of the manuscript and my husband, Mr. L. Marsh, advice with the mathematics. The Commonwealth Government Department of Shipping and Transport made available facilities at Low Isles and Lady Elliot Island. The co-operation of the personnel on both lightstations is gratefully acknowledged. Part of this work was done whilst I was supported by a Commonwealth Post-Gradu- ate Award. Literature Cited CERNOHORSKY, WALTER OLIVER 1964. The Conidae of Fiji (Mollusca: Gastropoda). The Veliger 7 (2): 61-94; plts. 12-18; 3 text figs; 1 map (1 October 1964) Day, Joun HEMswortH 1967. A monograph of the Polychaeta of Southern Africa. Brit. Mus. (Nat. Hist.), London. 878 pp. FAuVEL, PIERRE 1923. Polychetes errantes. Faune de France 5: 1 - 488 1927. Polychétes sedentaires. Addenda aux Errantes, Archi- annelida, Myxostromaires. Faune de France 16: 1 - 494 Nat. Acad. Sci. 42 (3): 168 - 171 1959. The ecology of Conus in Hawaii. 29: 47 - 90 1959a. The Hawaiian species of Conus (Mollusca : Gastro- poda). Pacific Sci., 13: 368-401; 2 plts.; 4 text figs. 1960. Ecological notes on Conus (Mollusca : Gastropoda) in the Trincomalee region of Ceylon. Ann. Mag. Nat. Hist. Ser. 13, 2: 309 - 320 1966. Food specialization in Conus in Hawaii and California. Ecology 47: 1041 - 1043 1968. Microhabitats, abundance and food of Conus on atoll reefs in the Maldive and Chagos Islands. Ecology 49 (6) : Ecol. Monogr. 1046 - 1061 Marsu, HELENE 1970. Preliminary studies of the venoms of some vermivorous Conidae. Toxicon 8: 271 - 277 Monro, C.C. A. 1931. Polychaeta, Oligochaeta, Echiuroidea and Sipunculoi- dea. Sci. Rept. Great Barrier Reef Exped. 4: 1 - 37 SaunpeErRs, Pau R. « Fay HENry WoLFson 1961. Food and feeding behavior in Conus californicus Hinps, 1844. The Veliger 3 (3): 73-76; plt. 13 (1 Jan. 1961) SHANNON, CLAUDE ELwoop & WARREN WEAVER 1949. The mathematical theory of communication. Univ. Illinois, Urbana STEPHENSON, T. A., ANNE STEPHENSON, GEOFFREY TANDY & MicHAEL SPENDER 1931. The structure and ecology of Low Isles and other reefs. Sci. Reprt. Great Barrier Reef Exped. 3: 17 - 112 STEPHENSON, WILLIAM, RoBERT ENDEAN & ISOBEL BENNETT 1958. An ecological survey of the marine fauna of Low Isles, Queensland. Austral. Journ. mar. freshwater Res. 9: 261 - 318 Page 54 THE VELIGER Vol. 14; No. 1 Host Texture Preference of an Ectoparasitic Opisthobranch, Odostomia columbiana Dall & Bartsch, 1909 KIRSTIN CLARK Department of Zoology, University of California, Berkeley, California 94720 and University of Washington Friday Harbor Laboratories, Friday Harbor, Washington 98250 (1 Plate) INTRODUCTION ALL MEMBERS OF THE FAMILY Pyramidellidae, which in- cludes Odostomia columbiana Dall « Bartsch, 1909, are considered to be ectoparasites, and each possesses a long, evaginable proboscis armed with a stylet which is used to extract body fluids from prey animals. In the region of Orcas Island, San Juan Archipelago, Washington, a pre- liminary survey indicated the incidence of association of O. columbiana with Trichotropis cancellata (Hinds, 1848), a filter-feeding prosobranch, to be about 41%. WiiuraMs (1964) has demonstrated that choice of substrate by certain polychaete larvae is influenced by physical properties of the substrate, such as texture and contour, as well as by biotic factors. More specifically, Hopkins (1956) found that rough surfaces of oyster shells attracted more Odostomia impressa (Say, 1821) than did smooth. Because of the unusual nature of the spiny peri- ostracum of Trichotropis cancellata (Figure 1), its con- tribution to substrate preference by Odostomia columbi- ana was examined. MATERIALS anp METHODS All experimental animals were maintained in aquaria provided with running sea water at the University of Washington Friday Harbor Laboratories. Trichotropis cancellata were collected in an area (known locally as the “potato patch”) of East Sound (approximately 48°40’ N, 122°55’ W) off Orcas Island during August, 1969. After noting the number of Odostomia columbiana on each host, the parasites were removed and were held separately. Empty host shells and Fusitriton oregonense (Redfield, 1848), a conch whose surface resembles that of T. cancel- lata, were also retained when recovered from the dredge. Experiments to determine the significance of host shell texture to host selection can be categorized as follows: (1) Odostomia columbiana were presented with alterna- tives involving living Trichotropis cancellata having differences in texture, (2) the alternative textures were present on a single snail, (3) Odostomia columbiana were presented with living Trichotropis cancellata together with empty shells having variations in surface texture, and (4) Fusitriton oregonense, with its similar surface charac- teristics was offered as an alternative to T: cancellata. Unless otherwise noted, two potential host animals were placed in a 10 cm square container with wire screen on 2 of the sides and a grid on the bottom, and the container was set into a sea table. The hosts were allowed to move about until neither changed position over a 3-hour period. At this time, one Odostomia columbiana was placed midway between the two animals and observed at 30 minute intervals until it had moved onto one of the hosts. At no time during continued observations was an O. columbiana seen to leave a host once it had attached. Occasionally, the parasite would brush against a Tricho- tropis cancellata and then move away. If no choice was made within 8 to 10 hours, the experiment was termi- nated. The first choice presented was a pair of Trichotropis cancellata, one untreated (Figure 7), and one with the periostracum completely removed (Figure 3). The peri- ostracum was removed by abrasion with a wire brush and a metal file. Control experiments used 2 normal snails, one with an identifying drop of paint at the top of the spire. In order to confirm that the choice of surface was nct influenced by differences between the snails, other than Tue VE IcER, Vol. 14 No. | {Kirstin Ciark] Figures | to 3 Figure 1 ’ Figure 2 Figure 1: An untreated Trichotropis cancellata with Odostomia columbiana near its aperture x af Figure 2: Trichotropis cancellata with a single strip of spiny peri- ostracum removed X at Figure 3: Trichotropis cancellata with spiny periostracum entirely removed X 2 Vol. 14; No. 1 THE VELIGER Page 55 that of their textures, the periostracum of single snails was removed in evenly spaced strips (Figure 2) such that there was an approximately equal amount of smooth and spiny surface in the form of 4 alternating strips, and these were given access to Odostomia columbiana. A third variation was the presentation of Odostomia columbiana with a choice between a living Trichotropis cancellata and an empty shell of this species. One alter- native was a living snail with the periostracum removed, and the other an empty shell with the usual surface texture. A living normal snail and an empty spinous shell provided the control. Finally, Odostomia columbiana was offered Trichotro- pis cancellata and Fusitriton oregonense (with which it is not known to be associated ). Because of the large size of F. oregonense these experiments were conducted in an 18cm < 30cm tank with running sea water. Twelve Odostomia were presented with one specimen of F ore- gonense and a sufficient number of T: cancellata to equal approximately the surface area of the former. RESULTS A strong preference for the intact spinous periostracum of Trichotropis cancellata was exhibited by Odostomia columbiana (Table 1B). This preference was also mani- fested when the alternative surface characteristics were present on a single snail (Table 1C). In experiments in which an empty spinous shell provided an alternative to a living snail lacking the periostracum, no such preference was noted (Table 2B), but a living aspinous T: cancellata was preferred to a shell of similar texture (Table 2A). Even in the presence of Trichotropis cancellata on which Odostomia columbiana were actually observed to feed, 2 of 10 parasites remained on Fusitriton oregonense for 7 days. DISCUSSION The results indicate that Odostomia columbiana responds to the surface texture of its host, Trichotropis cancellata. Strong evidence for a positive response to the spiny peri- ostracum is provided by the preference exhibited for the spinous strips, when these alternate with aspinous ones on a single snail, as both individual variation, and differ- ences introduced by handling, are minimized in these cases. The rejection of snails whose spinous surfaces had been entirely removed is confirmatory. Also, failure to prefer a living aspinous snail to a spinous, but empty shell indicates that surface texture Table 1 Responses of Odostomia to Living Hosts A B C Host Choice Both Untreated Treated and Untreated Strips on Single Snails with without Treatment None None None Periostracum removed Periostracum Periostracum Number attaching Observed (f) 15 13 30 5 34 7 Expected (F) 14 14 17.5 17.5 20.5 20.5 x? = 0.144 xX? = 16.46 YO = 117/7h83 p < 0.005 p < 0.005 Table 2 Responses of Odostomia to Empty Host Shells A Host Choice Empty Shell Living Snail Periostracum Periostracum Treatment removed removed Number attaching Observed (f) 1 6 Expected (F) B Empty Shell Living Snail Untreated Periostracum removed 12 8 10 10 XxX?) = 2183 Page 56 may be an important factor in maintenance of the associ- ation between Odostomia columbiana and Trichotropis cancellata. However, lack of preference for empty spinous shells suggests that surface characteristics alone do not determine host preference, and this is indicated as well by the preference for living snails over empty shells with identical surface characteristics. Establishment and maintenance of intimate associa- tion between two species is generally imperfectly under- stood, and most investigations have dealt with chemical location and recognition. Davenport (1966: 393) stated “Chemical sign stimuli are perhaps maximally important in the maintenance of aquatic partnerships in general.” Specific tactile information may also play a significant part in mediating and maintaining associations, and the present study has demonstrated that surface texture is an important component in the association of Odostomia columbiana with its host, Trichotropis cancellata. It may be that the spiny periostracum prevents the parasite from being dislodged by the strong currents, so that recognition and preference could assume positive adaptive value, and would be particularly useful to these opisthobranch para- sites which lack strong attachment organs. In the labora- THE VELIGER Vol. 14; No. 1 tory, at least, they are seen to move freely over all parts of the host shells. ACKNOWLEDGMENTS The author wishes to thank Tom Spight for his sugges- tions and Drs. C. M. Yonge and P. Illg for their helpful comments throughout the course of this study. ‘Literature Cited DAVENPORT, DEMOREST 1966. The experimental analysis of behavior in symbioses. pp. 381 - 429, In: S.M. Henry, Symbiosis, vol. 1. Acad. Press, New York Hopkins, SEWEL H. 1956. Odostomia impressa parasitizing southern oysters. Science 124: 628 - 629 Wi.uiAMs, G. B. 1964. The effect of extracts of Fucus serratus in promoting settlement of larvae of Spirorbis borealis (Polychaeta). Journ. Mar. Biol. Assoc. U. K. 44: 297 - 414 Vol. 14; No. 1 THE VELIGER Page 57 The Feeding and Reproductive Behaviour of the Sacoglossan Gastropod Olea hansineensis Agersborg, 1923 BY SANDRA CRANE Department of Biological Sciences, Simon Fraser University, Burnaby 2, British Columbia, Canada (1 Plate) INTRODUCTION SACOGLOSSANS ARE AN ORDER of opisthobranchs which typically have an herbivorous mode of feeding (Hyman, 1967). The family Oleidae has a single member, Olea hansineensis Agersborg, 1923, which has previously been recorded only on Brown Island in the vicinity of Friday Harbor, Washington (Figures /, 2). The original report by Acersporc (1923) comprises the only published know- ledge of this unique sacoglossan. The present study was done in the laboratory at Friday Harbor, and is the result of two months examination of approximately 40 specimens of various sizes which were collected for me by Dr. Thomas E. Thompson and Mr. Gordon Robilliard. HABITAT The specimens used in this study were collected inter- tidally and subtidally to 40 feet from Jaekle’s Lagoon and Garrison Bay on San Juan Island, and Parks Bay, Shaw Island. This extends the range of Olea only slightly from its original source at Brown Island. In all cases Olea is found in shallow embayments with mud bottoms, either upon, inside, or near the egg masses of the cephalaspidean opisthobranchs Haminoea virescens (Sowerby, 1833), Ag- laja diomedea (Bergh, 1894), or Gastropteron pacificum Bergh, 1893. FOOD SOURCES Olea hansineensis was reported by Agersborg to possess neither a single toothed radula nor an ascus. I confirmed by serial sectioning and by dissection the absence in Olea of these two diagnostic sacoglossan characters. Olea thus cannot feed in the typical sacoglossan manner, in which the single toothed radula is used to slit open cells of algae (Gonor, 1961). Instead, Olea has become the only known carnivore among the Sacoglossa. In the field I have observed Olea eating the eggs of Haminoea virescens, Aglaja diomedea and Gastropteron pacificum. In the laboratory they showed a wider range of diet, and would also eat eggs of nudibranchs as diverse as Archidoris montereyensis (Cooper, 1862), Hermissenda crassicornis (Eschscholtz, 1831), and Dendronotus iris Cooper, 1863. The only food source I found Olea utilizing was the eggs of other opisthobranchs. When recently fed specimens are sectioned or dissected, the midgut, particularly its branches into the cerata, is seen to contain veligers, giving the impression of a unique system for brooding eggs in the digestive tract (Figure 3). This illusion results from the fact that Olea is capable of eating eggs in any developmental stage, even completely shelled veligers just prior to hatching. These are not digested in the stomach region, but are passed immediately to the midgut. AcErsgore (1923) observed Olea floating upside down at the water surface and concluded they were eating microscopic organisms. Although I observed suspended animals for many hours in the laboratory, I rarely saw any movement of the mouth parts. Instead, the animals floated with the current, their heads bent down into the water and swinging back and forth. Considering the availability of high energy eggs which Olea is adapted to feed upon, it is unlikely that these movements are a form of feeding, but rather serve as a means of searching for food. Animals in aquaria were observed to move more than a meter to a new food source by this method. Page 58 FEEDING BEHAVIOUR Animals placed in a dish containing opisthobranch eggs travel randomly, moving the head constantly from side to side. Contact with egg masses appears to be accidental, although short distance chemoreception may occur. Once contact with the egg mass is made by the dorsal and ventral labial lobes, the animal moves onto the egg mass. If feeding is to take place, the animal pushes head first into the mass. Usually the entire animal enters, although at times only the head and neck are inserted. Cilia, covering its entire body, provide excellent propulsion in the viscous jelly which binds the eggs together. While Olea moves through the jelly between the strings of eggs, the labial lobes are constantly moving, pushing the jelly apart to allow the head and rest of the body to follow. Olea is very plastic, and flattens and twists its body to conform to the opening offered. When feeding, Olea consumes large quantities of eggs, as many as 15 to 20 a minute. The neck and head region are enlarged and curve downwards with the mouth open- ing into a large circular orifice. The muscular pharynx exerts a pumping action which can be detected in the slight back and forth movement of the animal when it is not completely inside an egg mass, and also in movement of the individual eggs which are pulled against the fer- tilization membrane several times before being pulled free. If the eggs are in the early stages of development they are sucked in along with the fertilization membrane. If eggs are in later stages, the egg membrane is usually broken by the suction and only the veliger is ingested, leaving behind an empty egg case with a slit down one side. The pumping action appears to continue constantly during feeding, but only when the oral lobes of Olea are applied directly to the egg case itself is the mechanism effective. Olea tends to follow along a string of eggs, engulfing each one until, by swinging the head, it begins on another row. More than a dozen individuals, ranging from 1 to 7 mm in length, have been observed living inside one 18 mm long Aglaja diomedea egg mass. Olea remains in an egg mass until all the eggs have either been eaten or have hatched. Feeding is infrequent; the animal feeds only a few times a day, usually for less than an hour each time. At other times, Olea either exhibits reproductive behav- iour, or enters an immobile resting state. While resting, most of the epidermal pigment is contracted, giving a pale cream color to the animal which blends with the egg mass. This corresponds to the “death feigning” observed by Acersgore (1923). I interpreted this behaviour as a resting state because it occurs most frequently when Olea has finished eating and is inside an egg mass, probably digesting its most recent meal. THE VELIGER Vol. 14; No. 1 REPRODUCTIVE BEHAVIOUR AND DEVELOPMENT Olea is gregarious and forms “courtship groups” from the time it is about 2 mm in length. Reproduction commences at approximately 4mm. Courtship groups occur when one animal trails another until it pushes the body of the first with its oral lobes. Both animals then stop and spend some time nudging each other. At times they may pause, either lying side by side, or head to tail in the copu- latory position. In this position mating is reciprocal, the penis of one being inserted in the female atrium of the other. Any animal moving nearby will join the pair and large groups may form. Grouping takes place on the sides of the container or the surface of an egg mass, and groups may remain together for an entire day. Animals oviposit the next day, the egg ribbon being laid in a counterclockwise coil of 14 to 4 turns, with 250 to 600 eggs per ribbon, arranged in a close spiral thread inside the jelly. The egg masses were laid on the sides of the container, as well as on the surface of Aglaja or Ha- minoea egg masses. Eggs were also observed inside the egg masses of Aglaja where they formed a thin thread in the jelly between the Aglaja egg cases. They appeared to develop normally in this situation, and although adult Olea often ate every egg in the Aglaja egg mass, the rib- bon of Olea eggs remained completely untouched. Indeed, adults were observed to recoil violently from their own egg mass by contracting and changing direction. Appar- ently, contact is necessary for recognition of their egg masses. Eggs follow the typical spiral cleavage and develop- ment of a Type I veliger (THompson, 1961). Hatching occurred on the sixth day. Veligers lived for only one week before dying. Metamorphosis would not take place although fresh Aglaja eggs were used as substrate. Recent- ly settled individuals found in the field were measured for initial growth rates. Ten individuals with a mean length of 1.65 mm grew to 3.75 mm in 9 days, and were spawn- ing by the twelfth day. The fast development of eggs and growth of young suggests that Olea has several generations in a season. This coincides with the hypothesis of Miter (1962) that opisthobranchs feeding upon a seasonal food supply have a large, rapidly reproducing population when the food is available, and only a few overwintering individuals. These individuals presumably exist on the remnants of the normal food supply or vary their diet to include the eggs of overwintering reproducers. Tue Ve uicer, Vol. 14 No. 1 [Crane] Figures 1 to 3 Figure 1 Figure 2 Figure 3 Figure 1: Lateral view of Olea hansineensis moving along the sur- face of an Archidoris montereyensis egg mass. The animal is 7 mm long. Figure 2: Dorsal view of Olea hansineensis emerging from an egg mass showing lateral labial lobes (L), dorsal labial lobe (D) and cerata (C). Figure 3: Lateral section of Olea hansineensis revealing the well developed eggs of Gastropteron pacificum in the midgut and its branches into the cerata. Contracting during preparation for sec- tioning forced most veligers out of the cerata. Vol. 14; No. 1 ACKNOWLEDGMENTS I would like to thank Dr. Thomas E. Thompson for suggesting this study, and Drs. Stoner B. Haven and Wil- liam C. Austin for critizing the manuscript. Photographs were taken by Mr. Ron Long. Supported by a National Science Foundation grant to Friday Harbor Laboratories. Literature Cited AcERSBoRG, HELMER PaRELI von WoLp KJERSCHOW 1923. | Notes on a new cladohepatic nudibranch from Friday Harbor, Washington. The Nautilus 36 (4): 133 - 138; plt. 6 THE VELIGER Page 59 Gonor, JEFFERSON JOHN 1961. Observations on the biology of Hermaeina smithi, a sacoglossan opisthobranch from the west coast of North Amer- ica. The Veliger 4 (2): 85-98; 13 text figs. (1 Oct. 61) Hyman, Lippy HENRIETTA 1967. Mollusca, I. vol. 6 of The Invertebrates, 762 pp.; illust. McGraw-Hill Book Co., New York Miter, MicHAEL CHARLES 1962. Annual cycles of some Manx nudibranchs with a dis- cussion of the problem of migration. Journ. Anim. Ecol. 31: 545 - 569; 12 text figs. TuHompson, THomaAs EveRETT 1961. The importance of the larval shell in the classification of the Sacoglossa and the Acoela (Gastropoda, Opisthobranchia) . Proc. Malacol. Soc. London 34 (5): 233 - 239 Page 60 THE VELIGER Vol. 14; No. 1 Observations on the Sea Hare Aplysia parvula (Gastropoda : Opisthobranchia) from the Gulf of California BY JAMES R. LANCE Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92037 (4 Text figures) INTRODUCTION On January 7, 1966, several intertidal opisthobranchs were collected on the northeastern shore of the Gulf of California at Bahia San Carlos, Sonora, Mexico, and transported alive to Scripps Institution of Oceanography where they were maintained in aquaria with running sea water. Along with several species of cephalaspideans and nudibranchs, the collection contained an adult individual of the small sea hare Aplysia (Pruvotaplysia) parvula Guilding in Morch, 1863. Although of common occur- rence in other warm seas of the world, the present speci- men represents the third verifiable record of this circum- tropical species in eastern Pacific waters. I am very grate- ful to Mr. and Mrs. Carlos Pickering of San Diego for placing this material at my disposal. The following diagnosis refers to the present specimen which, except for some minor color variations, appears to be typical of this species. DESCRIPTION Body small (expanded, 36mm long), flaccid, elongate, tapering to a bluntly pointed tail, neck slender (Figure 1) ; skin soft, smooth; foot slightly narrower than body, truncate in front, margins and sole smooth (Figure 2). Rhinophores slender, tapering distally, slit along their outer faces, positioned closer to head tentacles than to anterior parapodial origins. (adjacent column —>) Figure 1 Aplysia parvula Dorsal view of animal in life Vol. 14; No. 1 THE VELIGER Page 61 Figure 2 Aplysia parvula Antero-ventral view of animal in life Head tentacles auriculate, directed forward and out- ward, the upper face inrolled, tubular, the lower surface developed into a foreshortened flap with irregularly scal- loped or ragged edges. Parapodia moderately developed, the rounded anterior margins widely separated, united behind to form an up- standing wall around the mantle cavity. Mantle thin, exposed, the posterior end complexly rolled to form a cylindrical anal siphon; the oval mantle aperture exceptionally large — at least 4 the shell width. Ground color a rich reddish brown, mantle and foot paler; dorsum and sides profusely sprinkled with opaque white or yellowish dots which often occur in irregular patches; similar patches along inner and outer parapodial borders forming a nearly linear series; distal margins of head tentacles and rhinophores, anterior border of foot and edges of parapodia and mantle aperture an intense, velvety black or blue-black. Shell proportionately large (7.3 mm long, 4.9mm wide), dorsal surface strongly convex, subovate, entirely calci- fied except for a narrow cuticular margin, surface ridged with concentric growth lines (Figure 3); ventral face smooth, slightly nacreous, concave; apex incurved, de- limitation of larval shell conspicuous (Figure 4) ; color pale yellowish brown. Labial armature composed of minute straight or slight- ly curved rodlets formed into subtriangular plates. Radula Figure 3 Aplysia parvula Dorsal view of shell Figure 4 Aplysia parvula Ventral view of shell formula 27 14-1-14; rachidian tooth strong, the base produced into widely separated prolongations, central cusp prominent, its margins bearing 5-8 denticles on either side and 3 smaller lateral cusps which decrease in size outwards; lateral teeth with simple, pointed bases, Page 62 their denticulation similar to rachidian; outer 3 margin- als simple subrectangular plates. Opaline gland primarily simple, secondarily with co- alescing ductules. Purple gland present. Details of the anatomy, color variations, synonymy, and geographical distribution will be found in MacFarLtanp (1924), ENcex (1936), Basa (1949), OstercaarD (1950, 1955), Burn (1957), Eates (1960), Kay (1964) and Marcus & Marcus (1967). DISCUSSION The only verifiable records of Aplysia parvula occurring in the eastern Pacific are those of MAcFartanp (1924: 398) who reported on 3 strongly contracted and macerated specimens from Isla San Marcos in the central part of the Gulf of California, and Marcus « Marcus (1967: 154) who examined a single preserved specimen from Puerto Penasco, Sonora. In her classical “Revision of the World species of Aplysia,’ EaLes (1960: 288) gave the eastern Pacific range as“. . . California, South California and the west coast of South America.” BEEMAN (1963: 145) has rightly questioned this distribution. The “California” record is unsubstantiated, and intensive collecting along most of the California coast during the past 20 years has failed to yield a single specimen. Eales’ second locality, “South California,” is presumed to refer to MacFarland’s 3 spe- cimens from Isla San Marcos since no other Panamic records were extant at that time. I have been unable to locate the source of her third reported locality — “west coast of South America.” In recent years the Gulf of California has been the focal point for rather intensive opisthobranch collecting. Accordingly, it is curious that such a relatively conspicu- ous species should have been found so rarely, especially in view of its abundance in other tropical and subtropical seas. Perhaps the answer may be attributed, at least in part, to its retiring habits. Kay (1964: 176), for example, reports that individuals from Hawaii are usually found buried in the sand-algal mat or entangled in long strands of algae. Of the 48 animals she observed, only 2 were found “... crawling freely over the substrate.” The present specimen was found similarly buried in sand at the base of Padina durvillaei Bory de Saint Vincent, 1827. Basa (1949: 125) reported the species to be “Common almost everywhere on the Pacific coasts of Japan,” but did not indicate any specific habitats. Little is known about the spawning habits of Aplysia parvula. After 5 days of confinement in running sea water, our specimen became moribund and extruded a few typical aplysid egg strings on the aquarium wall. The fresh spawn was bright yellowish-green, viable, and gen- THE VELIGER Vol. 14; No. 1 erally agreed with that described for Japanese (BABA ef al., 1956: 216) and Hawaiian (Kay, 1964; 176; OsTErR- GAARD, 1950: 100) specimens. Unlike other northeastern Pacific aplysids for which data are available, for example A. californica Cooper, 1863, and A. vaccaria Winkler, 1955, whose capsules have been observed to contain up to 100 or more eggs, A. parvula has been reported to deposit capsules with only 1 (OsTERGAARD, loc. cit.) or 2-3 (Basa et al., loc. cit.) eggs. The former observation, however, may be based on an erroneous species identifica- tion (see Eases, 1960: 288). Although many of the capsules laid by our specimen were empty, most contained 1 or 2 eggs — a few, 3. However, the scantiness of spawn and unhealthy condition of the present specimen do not permit definitive conclusions regarding normal repro- ductive activity. No attempt was made to maintain or hatch the devel- oping embryos. Numerous species of local algae were offered the animal but no feeding response occurred. Literature Cited Basa, K1KUTARO 1949. Opisthobranchia of Sagami Bay, collected by his Majesty the Emperor of Japan. Tokyo. 104 pp.; 50 plts.; 7 text figs. Biol. Lab. 8 (1) :79- 85; plts. 7, 8 (November 1949) Basa, KixutTaro, Iwao HAMATANI & Kerjiro Hisat 1956. Observations on the spawning habits of some of the Japa- nese Opisthobranchia (II). Publ. Seto Mar. Biol. Lab., 5 (2): 209 - 220; plts. 24, 25; figs. 1-3 (June 1956) BEEMAN, Ropert Davip 1963. Notes on the California species of Aplysia (Gastropoda: Opisthobranchia). The Veliger 5 (4): 145-147. (Apr. 1, 1963) Bory DE SAINT VINCENT, J. B. 1826. Histoire naturelle botanique, Cryptogamie. m L. DuperrEy, Voyage autour du monde . . . surla Corvete .. . La Coquille ... pp. 1-96 (1827), Paris Burn, RoBERT 1957. On some Opisthobranchia from Victoria. Journ. Malacol. Soc. Austral. no. 1: 2- 17; plts. 1- 3 (25 March 1957) Cooper, JAMES GRAHAM 1863. | On new or rare mollusca inhabiting the coast of Cali- Proc. Calif. Acad. Nat. Sci. 3 (2) : 56-60 (17 August 1863) fornia. Eases, NEE B. 1960. Revision of the world species of Aplysia (Gastropoda, Opisthobranchia). Bull. Brit. Mus. (Nat. Hist.) Zoo. 5 (10): 267 - 404; frontispiece; 51 text figs. (January 1963) ENGEL, HEeNnprik « P. WAaGENAAR HUMMELINCK 1936. | Uber westindische Aplysiidae und Verwandten anderer Gebiete. Capita Zoologica 8 (1): 1-76; 43 text figs. Kay, E. ALISON 1964. The Aplysiidae of the Hawaiian Islands. Proc. Malacol. Soc. London 36 (3): 173-190; fig. 1; plt. 8 (8 May 1964) Vol. 14; No. 1 THE VELIGER MacFaruanp, Frank Mace 1924. Expedition of the California Academy of Sciences to the Gulf of California in 1921. Opisthobranchiate mollusca. Proc. Calif. Acad. Sci., ser. 4, 13 (25): 389-420; plts. 10-12. (29 November 1924) Marcus, EvELINE pu Bois-REYMOND & ErNsT Marcus 1967. American opisthobranch mollusks. Stud. Trop. Oce- anogr. Miami 6: vili+ 256 pp.; figs. 1-55, 1-95 (Dec. ’67) Morcu, Orro AnprEas Lowson 1863. Contributions 4 la faune malacologique des Antilles dan- oises. Journ. Conchyliol., 3° serie. 3 (11): 21-43 OsTERGAARD, JENS MaTuias 1950. Spawning and development of some Hawaiian marine gastropods. Pacific Sci. 4: 75 - 115; figs. 1 - 42 (April 1950) 1955. Some opisthobranchiate mollusca from Hawaii. Pac. Sci. 9: 110 - 136; figs. 1-17; plts. 1, 2 (April 1955) WINKLER, LINDSAY ROBERT 1955. A new species of Aplysia on the southern California coast. Bull. So. Calif: Acad. Sci. 54 (1): 5-7; plts. 2, 3 Page 63 Page 64 THE VELIGER Vol. 14; No. 1 Cypraca: A List of the Species. II. BY JERRY DONOHUE Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (1 Text figure) Now, AT LAST, that the beautiful and long awaited book on living cowries by Burcess (1970) has appeared, it seems appropriate to update an earlier analysis (Dono- HUE, 1965) of the situation regarding a definitive listing of the valid species of Cypraea. Such a list should be of interest to cypraeophiles. Unfortunately, Burgess’ appar- ently definitive treatment of this problem is in incomplete agreement with the latest treatment of the same problem from another source (ScHILDER, 1969) well known for its expertise in this genus (s./.). This lack of agreement probably should have been anticipated. Indeed, there is incomplete agreement where it might have been hoped to exist, e. g., among ScHILDER, 1965, 1967 and 1969. We therefore choose for treatment below only the two most recent sources cited above. ScHILDER (1969) lists 170 species and 21 “prospecies,” and Burcess (1970) lists 185 species while remarking that 3 more taxa need more study; however, in an ad- Table 1 Species of C'ypraea accepted by both ScuiLper (1969) and Burcess (1970) [A of Figure 1] achatidea childreni fimbriata albuginosa chinensis friendu algoensis cicercula fultont amphithales cinerea fuscodentata angustata citrina fuscorubra annettae clandestina gambiensis annulus cohenae gangranosa arabica contaminata gaskoint arabicula coxent globulus argus cribellum goodallu armeniaca cribraria gracilis artuffelt cumingit granulata asellus cylindrica grayana aurantium decipiens guttata barclayi declivis hammondae becku depressa helvola bistrinotata dillwyni hesitata bowinit diluculum hirasei broderipu edentula hirundo camelopardalis eglantina histrio capensis englerti hungerfordi caputdraconis erosa interrupta caputserpentis errones irrorata carneola erythraeensis isabella catholicorum esontropia katsuae caurica exusta kienert cernica felina labrolineata ceéruus lamarckit ocellata Scurra langfordi onyx Spadicea lentiginosa ostergaardt spurca leucodon ovum staphylaea limacina owenit stercoraria lurida pallida stolida lutea pallidula subviridis lynx pantherina sulcidentata macandrewt picta surinamensis maculifera pipenta talpa mappa poraria teramachi marginalis porteri teres marginata pulchella tessellata mariae pulchra testudinaria martint pulicaria teuleret mauiensis punctata tigris mauritiana pyriformis turdus mexicana pyrum ursellus microdon quadrimaculata valentia midwayensis rabaulensis ventriculus miliaris rashleighana venusta minoridens reevet vitellus moneta robertsi vredenburgi mus rossellt walkeri nigropunctata sanguinolenta xanthodon nivosa saulae zebra nucleus schilderorum ziczac zonaria Vol. 14; No. 1 THE VELIGER Page 65 ‘Table 2 Taxa of Cypraea in disagreement status in: reference taxon ScHILDER, 1969 Burcess, 1970 in Figure 1 thersites species doubtful (= friendii?) B bicolor species variation of piperita Cc cater species variation of venusta Cc queenslandica species variation of hirasei C hartsmithi species not mentioned D stohlen species not mentioned D aequinoctialis prospecies species E bregeriana prospecies species E cervinetta prospecies species E coloba prospecies species E eburnea prospecies species E fernandoi prospecies species E petitiana prospecies species E semiplota prospecies species E serrulifera prospecies species E subteres prospecies species E yaloka prospecies ? species E acicularis prospecies doubtful (= spurca?) F nebrites prospecies doubtful (= erosa?) F adusta prospecies variation of onyx G dorsalis prospecies variation of subviridis G fischer prospecies synonym of gaskoini G listert prospecies variation of felina G notata prospecies synonym of gracilis G raysummerst prospecies variation of hammondae G superstes prospecies synonym of martini G tomlini prospecies variation of cernica G cassiaut subspecies species H comptonu cline species H kuroharai subspecies species H leviathan mutant species H luchuana cline species H obvelata cline species H summerst cline species H margarita cline doubtful (= cicercula?) I dayritiana not mentioned species J musumea not mentioned species jj thomasi not mentioned species J gondwanalandensis (new) species K steineri (new) species K 1 as humphreysii (see BurcEss, p. 86) Page 66 THE VELIGER Vol. 14; No. 1 Burcess, 1970 ScHILperR, 1969 21 prospecies numerous subspecies, clines, mutants not mentioned (new) Differences in assignments of 204 taxa of Cypraea numerous variations, color forms, synonyms Figure 1 dendum, Burcess accepts 4 sp. nov., places 1 of the 185 into the synonymy (/atior) and 1 of the 185 into the doubtful classification (nebrites). The net opinion of Burgess is thus 187 species plus 4 provisional or doubtful species. The fact that 170421 —187+4 is merely a numerical coincidence: the differences between the Schil- der and Burgess lists are far more subtle. A complete analysis of the two lists is presented in Figure 1. The details of the differences which appear in Figure 1 are presented in Tables 1 and 2. The two authorities agree on the status of 164 taxa as species. It is interesting that of the 21 prospecies of Schilder, Burgess accepts 11 as species, considers 2 doubt- ful, and relegates 8 to synonymy. It is also interesting that 2 of the species recognized by Schilder are not mentioned by Burgess, while 3 of the species recognized by Burgess are not mentioned by Schilder. The overall picture, how- ever, is on the hopeful side, for there appears to be less confusion than there was as recently as 5 years ago. Literature Cited Burcess, C. M. 1970. The living cowries. A.S. Barnes & Co., Cranbury, N. J. pp. 1 - 389; plts. 1-44 DoNOHUE, JERRY 1965. Cypraea: a list of the species. 219 - 224 ScHILDER, FRANZ ALFRED The Veliger 7 (4): (1 April 1965) 1965. The geographical distribution of cowries (Mollusca: Gastropoda) The Veliger 7 (3): 171 - 183; 2 maps (1 January 1965) 1969. Zoogeographical studies on living cowries. The Veliger 11 (4) : 367 - 377; 1 map ScHILDER, Maria 1967. | Length, breadth, and dentition in living cowries. The Veliger 9 (4) : 369 - 376; 1 diagram (1 April 1967) (1 April 1969) Vol. 14; No. 1 THE VELIGER Page 67 Ten New Species of Tropical Eastern Pacific Turridae DONALD R. SHASKY * 734 West Highland Avenue, Redlands, California 92373 (1 Plate) INTRODUCTION THE NUMBER OF UNDESCRIBED species of Turridae from the tropical Eastern Pacific may seem to many observers to be limitless. Despite the diligent collecting efforts of Cuming, Hinds, Reigen, C. B. Adams, The U.S. Bureau of Fisheries, Zetek, Lowe, and others, many new species continue to be recognized from collections made by con- temporary collectors. Generic relationships of the Turridae have been poorly understood. Dr. James McLean’s current work is shedding considerable light into this area. The classification followed in this paper follows that proposed by McLEan in this issue of The Veliger. Abbreviations for type repositories mentioned in the text are as follows: AHF Allan Hancock Foundation (collection on loan to LACM) AIM Auckland Institute and Museum, Auck- land, New Zealand AMNH ~ American Museum of Natural History, New York ANSP Academy of Natural Sciences, Phila- delphia CAS California Academy of Sciences, San Francisco LACM Los Angeles County Museum of Natural History SDMNH San Diego Museum of Natural History SU Stanford University, Stanford, California USNM United States National Museum of Nat- ural History, Washington, D.C. * Research Associate in Invertebrate Zoology, Los Angeles County Museum of Natural History. ACKNOWLEDGMENTS I wish to thank Dr. James H. McLean of the Los An- geles County Museum of Natural History for many favors, including the loan of specimens, supplying needed ref- ferences, much advice, and his critical reading of this paper, to Dr. S. S. Berry, Helen DuShane, Dr. Leo Hert- lein, and Roy Poorman for the loan of specimens, and to Capt. Xavier Mendoza, Dr. Agustine Ayala, and Dr. Antonio Garcia-Cubas, all of Mexico City, for opening many doors for me in their great country. 1. Doxospira hertleini Shasky, spec. nov. (Figure 1) Description: Shell rather large, fusiform; color yellowish white with weak yellowish brown bands on some speci- mens just superior to the suture; shell covered with a rather adherent brownish gray periostracum; protoconch of 4 eroded conical whorls; subsequent whorls about 12; suture a shallow indistinct groove; whorls separated by a wide subsutural channel which on the body whorl is sculptured with fine incremental lines that radiate out like wavelets from the anal fasciole; these are obscured adapically by fine spiral threads; axial sculpture of 7 short ribs on the early whorls, increasing to 9 longer ribs on the body whorl; spiral sculpture of major and minor threads that alternate, there generally being 3 major and 2 minor threads on the early whorls; however the minor threads are obscured on some specimens; aperture glistening white; outer lip thin, gently flaring, smooth within and with a moderate stromboid notch at the lower end; colu- mella straight and smooth; siphonal canal short and slightly recurved; anal fasciole open and wide with a thick callus at the sutural angle. Dimensions of holotype: height Page 68 41.8 mm, diameter 16.6 mm, length of aperture 18.5 mm. Type Locality: Holotype and 8 paratypes from 77-112 m, 14 miles SSE of Judas Point, Costa Rica, 9°19’32” N, 84°29’30” W, CAS locality 17974. Leg. Wm. Beebe, March 1, 1938. Type Material: Holotype, CAS 13288, 3 paratypes, CAS 13289, 13290, 13291, 1 paratype, LACM 1565, single para- types, SDMNH, AMNH, USNM, and Shasky collection. Referred Material: CAS 27557, 1 specimen, 91-110 m, Punta Arenas, Costa Rica; CAS 17986, 1 specimen, 64 m, Gulf of Chiriqui, Panama; CAS 17996, 1 specimen, 73 m, Hannibal Bank, Panama; AHF 854-38, 1 specimen, 73- 110 m, Gorgona Island, Colombia; AHF 213-34, 3 speci- mens, 13-18 m, La Plata Island, Ecuador. Discussion: This species is monotypic for Doxospira Mc- Lean, 1971. On shell characters Doxospira hertleini seems closest to Compsodrillia bicarinata (Shasky, 1961). C. bi- carinata is a more slender shell with fewer and sharper spiral cords and chocolate brown color bands. Immature specimens of Doxospira hertleini, which lack the anal callus, might be confused with species of Knefastia. It is a pleasure to dedicate this species to Dr. Leo Hert- lein of the California Academy of Sciences, San Francisco. 2. Miraclathurella mendozana Shasky, spec. nov. (Figure 2) Description: Shell of moderate size for the genus, brown, biconic; nucleus of 3 glossy, brown whorls, smooth ex- cept for a single peripheral keel; the first nuclear turn somewhat flattened; remaining whorls 6-7; the first 3 mature whorls have strong axial ribs and the continuing peripheral keel; on succeeding whorls the axial sculpture progressively becomes weaker and the spiral threads stronger, which renders these whorls finely cancellate; there are about 23 axial riblets and 5 spiral threads on the penultimate whorl and 27-33 axial riblets on the body whorl; suture impressed, with an adjacent strong subsu- tural cord; between the subsutural cords and the adapical spiral threads is a shallow channel with fine opisthocyrt growth lines; aperture smooth and glossy, of creamy- brown color; outer lip arcuate, sharp-edged, slightly crenulate, edentulous and varicose, with a shallow strom- boid notch; columella smooth and gently curved; siphonal canal open, short, and slightly recurved; anal notch deep, with moderate subsutural callus. Dimensions of holotype: height 16.1 mm, diameter 5.3 mm, height of aperture 7.8mm. THE VELIGER Vol. 14; No. 1 Type Locality: Holotype and 4 paratypes from 37—73 m, mud bottom, Gulf of Tehuantepec, Mexico, 15°43’ N, 96°07’ W, San Juan Expedition station G-5. Leg. Donald Shasky, July 14, 1963. Type Material: Holotype, LACM 1566, single paratypes, CAS, SDMNH, USNM, Shasky Collection. Referred Material: Shasky Collection. Gulf of Tehuan- tepec, San Juan Expedition, 3 specimens from station E-3, 73 m; 1 specimen from station E-9, 146 m; NW side Espiritu Santo Island, Gulf of California, Ariel Expedi- tion, 1 specimen, 146 m; LACM 38-6, Chamela Bay, Jalisco, Mexico, 1 specimen, 27-73 m; LACM 38-9, Gua- tulco Bay, Oaxaca, Mexico, 11 specimens, 73-128 m; AHF bottom sample station 548, Cupica Bay, Colombia, | speci- men, 22 m. Discussion: Miraclathurella mendozana is closest to M. woodringi (Pilsbry and Olsson, 1941) described as a Plio- cene fossil from the Canoa Formation, Punta Blanca, Ecua- dor. Most notable difference is the greater number of axial riblets on the body whorl of M. mendozana (27-33 as compared to 21 for M. woodringi). They may be only subspecifically different. It is named in honor of Capt. Xavier Mendoza von Borstel, of Mexico City. 3. Strictispira stillmani Shasky, spec. nov. (Figure 3) Description: Shell of medium size for the genus, biconic; color dark brown on the early whorls, shading to black on subsequent whorls; nucleus of 3 smooth, glistening, coni- cal whorls; remaining whorls 7; suture shallowly chan- neled; axial sculpture of 16 sigmoid ribs occupying about 2/2 of the abapical portion of the whorl, except on the body whorl where they are much longer; ribs abapically touch- ing the suture; spiral sculpture a single strong subsutural keel, terminating at the callus of the anal sulcus; most specimens fail to show spiral threading until the penullti- mate whorl and frequently not until the body whorl; spiral threads commence as faint striae that do not cross the ribs, becoming stronger on the mid-portion of the body whorl where they cross over the ribs, and terminally becoming strong enough to obliterate the ribs entirely; aperture glistening, with outer lip, anterior canal, and columella chocolate brown, abruptly changing to gray in the throat; outer lip undulate; anterior canal short and open, hardly distinct from the aperture; anal sulcus con- stricted at the opening by a thick subsutural callus; the sulcus expands into a rounded canal that is nearly at right Vol. 14; No. 1 angles to the long axis of the shell; periostracum thin, dark, slate-blue. Dimensions of holotype: height 14.7 mm, diameter 5.8 mm. Type Locality: Holotype and 71 paratypes at low tide from Venado Island, Panama Canal Zone, 8°53’ N, 79° 36’ W, LACM locality 70-15. Leg. James McLean and Donald Shasky, March 8-11, 1970. Type Material: Holotype, LACM 1567, 18 paratypes, LACM 1568, 2 paratypes each to AIM, AMNH, ANSP, CAS, SDMNH, SU, USNM, and S.S. Berry collection, 39 paratypes, Shasky collection. Referred Material: Shasky collection: Punta San Felipe, Baja California, 74 specimens; Agua de Chale, Baja Cali- fornia, 24 specimens; Puertocitos, Baja California, 4 spe- cimens; Mazatlan, Sinaloa, 6—7 m, 2 specimens; Cuaste- comate, Jalisco, 8-15 m, 2 specimens. LACM: specimens from San Felipe, Puertocitos, Point Arena, and Cape San Lucas, Baja California, and Banderas Bay, Jalisco. Discussion: Crassispira (Striospira) xanti Hertlein and Strong, 1951, has axial ribs, a subsutural keel and a color similar to Strictispira stillmani, but the biconic shape of S. stillmani and the shallow, broad anal notch of C. xanti help to rather easily separate these species. I have previously distributed a few specimens of Stricti- spira stillmani under the name Crassispira paxillus (Sow- erby, 1834). The published figures of C. paxillus, which was described from an unknown habitat, suggested this possibility. A photograph of the type of C. paxillus, sup- plied by Dr. Myra Keen, removed it from further consid- eration as it is a chunkier shell with more and weaker axial ribs, and the apparent absence of a subsutural keel. The new taxon is named for Dr. S. Stillman Berry of Redlands, California. 4. Zonulispira chrysochildosa Shasky, spec. nov. (Figure 4) Description: Shell medium size, dark brown, whorls 1014; nucleus flat-topped, of 214 shiny whorls; the first 114 smooth, the next with about 11 oblique riblets that dis- appear at the beginning of the succeeding whorl; arising on the first postnuclear whorl is a strong suprasutural, sharply nodose, yellow-gold, spiral carina, which on later whorls migrates to the center of the whorl; this termi- nates at the edge of the outer lip abapical to the anal notch; a second weaker, subsutural, undulating carina also commences on the first postnuclear whorl, which is dark brown but gradually becomes golden; it ends at THE VELIGER Page 69 the anal callus; on the antepenultimate whorl a third somewhat nodular golden carina appears just above the suture; this terminates in the outer lip just abapical to the strongly nodose carina; on the body whorl there are 10 golden smooth or nodose bands, including the 3 pre- viously described; the nodes of the primary carina are arranged in axial rows with 9 on the penult and 10 on the body whorl; numerous fine spiral threads and even finer intersecting growth lines fill the spaces between the carinae; the suture is a shallow undulating groove; aper- ture elongately oval, smooth, brown, shading to gray in the throat; outer lip coarsely crenulate; columella smooth; anterior canal short, open, slightly recurved; anal notch with a strong callus that partially constricts the opening. Dimensions of holotype: height 20.9 mm, diameter 8.1 mm. Type Locality: Holotype and 44 paratypes collected at low tide, Venado Island and adjacent Veracruz Beach, Panama, 8°53’ N, 79°36’ W. Leg. Donald Shasky, Decem- ber 3, 1967; Donald Shasky and James McLean, March 8-11, 1970. Type Material: Holotype, LACM 1569, 20 paratypes, LACM 1570, single paratypes, AIM, AMNH, ANSP, CAS, SDMNH, SU, and USNM, 17 paratypes, Shasky col- lection. Referred Material: USNM 55468, 1 specimen, Panama, Stearns collection; USNM 216940, 1 specimen, Panama, leg. Zetek; AHF 214-34, 1 specimen, 4 m, Cape San Fran- cisco, Ecuador. Discussion: Zonulispira chrysochildosa resembles Z. grandimaculata (C. B. Adams, 1852) and Z. zonulata (Reeve, 1843), but is broader than either and all the spiral cords of the base are slightly marked, rather than only the peripheral and one basal cord. It is evidently common at Panama at present. Surprisingly, the only specimens found in old collections are the 2 USNM lots mentioned above. The name is derived from the Greek words, chrysos— gold, and childosis—ornamentation. 5. Pilsbryspira (Pilsbryspira) garciacubasi Shasky, spec. nov. (Figure 5) Description: Shell of medium size, turreted, of light gray to slate to black color, and with orange carinae and beads; protoconch whorls 34, glossy, dark brown, last 114 whorls with diagonally slanted axial ribs, 13 per whorl; post- Page 70 nuclear whorls 9; axial ribs do not appear until the penultimate or body whorl where they occupy the mid- dle of the whorl; they are weak and number about 17; spiral sculpture of a strong row of orange interconnect- ing beads over the abapical third of the whorls which terminates at the abapical edge of the anal notch; beads bifid on early whorls, but single on later whorls; addi- tional spiral sculpture of 2 grayish-white carinae that eradually become orange; the first of these is subsutural and commences on the first postnuclear whorl and termi- nates just adapical to the anal notch; the second, which undulates, begins on the sixth to eighth postnuclear whorl, terminating in the outer lip after becoming beaded on the body whorl; on the body whorl, arising at the inner lip and ending at the outer lip margin, are 6-7 parallel rows of interconnected beads or carinae, which are usually of less color intensity than the previous spiral sculpture; spaces between all carinae are densely packed with micro- scopic spiral lines that are faintly cut by opisthocyrt growth lines; on some specimens below the main row of beads on the body whorl these fine spirals are much more strongly and regularly cut with orthocline growth lines, rendering this area delicately cancellate; aperture elon- gately oval, varying from white to gray, to black or com- binations of these colors; inner lip smooth; outer lip coarsely crenulate; anterior canal short, open; anal notch a short, open slit; anal callus moderate. Dimensions of holotype: height 13.3 mm, diameter 4.5 mm. Type Locality: Holotype and 10 paratypes from 2-15 m, under rocks, Cuastecamate Cove, Jalisco, Mexico. 19° 1345” N, 104°44’53” W. Leg. Donald Shasky, August 8-9, 1965; Donald Shasky and James McLean, October 13-21, 1968. Type Material: Holotype, LACM 1571, 3 paratypes, LACM 1572, single paratypes, AMNH, ANSP, CAS, SDNHM, USNM, 2 paratypes, Shasky collection. Referred Material: LACM 68-2, 7 specimens, Santa Cruz, Nayarit, Mexico; LACM 70-7, 8 specimens, Punta Mita, Nayarit, Mexico; LACM 67-23, 1 specimen, Acapulco, Guerrero, Mexico; Shasky collection, 1 specimen, Bahia Santa Cruz, Oaxaca, Mexico. Discussion: Pilsbryspira loxospira (Pilsbry and Lowe, 1932), and P. garciacubasi are similar in color patterns, size and habitat. P. garciacubasi has a straight rather than “bent” axis, 17 rather than 10—11 axial ribs, much weaker growth lines, and a less contracted opening to the anal notch. Pilsbryspira collaris (Sowerby, 1834), also of similar coloration, has fewer spiral threads, bifid peripheral bead- ing on the final whorl, and is a smaller chunkier shell than P. garciacubasi. THE VELIGER Vol. 14; No. 1 This new taxon is named for Dr. Antonio Garcia-Cubas, Jr., micro-zoologist of the Instituto de Biologia, Uni- versidad Nacional Autonoma de Mexico. 6. Glyphostoma (Glyphostoma) myrae Shasky, spec. nov. (Figure 6) Description: Shell of medium size for the genus, whorls 814-9; nuclear whorls 214-3, brownish, inflated, smooth except for a central carina; adult whorls with elevated axial ribs, 11 on the body whorl, but progressively dimin- ishing in number adapically; ribs attenuated or obscured on the base; spiral sculpture of numerous threads, stronger over the ribs; 12 threads on the penultimate whorl and about 30 on the body whorl; microscopic axial riblets cross the first 2-3 subsutural spiral threads of the penultimate and body whorls; virtually the entire external surface of the shell, except the nucleus, is studded with microscopic granules; suture indistinct, undulate; aper- ture narrowly elongate, white within except for brown stains on the alveolar ridge and the columellar lip; outer lip crenulate, varicose, flaring, and with 7-8 denticles, the adapical and abapical the strongest; columellar lip with 8 plicae; anterior canal relatively long, open, re- curved, anal notch open and moderately callused; color yellowish-white with a yellowish-brown subsutural band on all of the whorls below the nucleus, and another simi- larly colored band on the body whorl diffuses into a lighter still brownish shade on the base. Dimensions of holotype: height 12.9 mm, diameter 6.8 mm. Type Locality: Holotype and 1 paratype from 46 m off Jicarita Island, Panama, 7°12’ N, 81°47’ W. Leg. Capt. Fred Lewis, 1937. Type Material: Holotype, LACM 1573; 1 paratype, Shasky collection. Referred Material: AHF 423-35, 2 specimens, 37 m, off Port Utria, Colombia; AHF bottom sample station 505, 1 specimen, 59 m, Gorgona Island, Colombia. Discussion: Glyphostoma myrae has a characteristic color pattern and should not be confused with any known East- ern Pacific Glyphostoma. It is a pleasure to dedicate this species to Dr. Myra Keen, of Stanford University. 7. Kurtziella (Rubellatoma) powelli Shasky, spec. nov. (Figure 7 ) Description: Shell small, fusiform, 7 whorled; nucleus of 3 dome-shaped helicoid whorls, the first 2 smooth, the Tue VE icER, Vol. 14, No. 1 [Suasky] Figures / to 10 Figure 4 Figure 6 Figure 7 Figure /: Doxospira hertleini Shasky, spec. nov. Holotype, X 1.6 Figure 2: Miraclathurella mendozana Shasky, spec. nov. Holotype, X 3.0 Figure 3: Strictispira stillmani Shasky, spec. nov. Holotype, X 3.0 Figure 4: Zonulispira chrysochildosa Shasky, spec. nov. Holotype, X 2.1 Figure 5: Pilsbryspira (Pilsbryspira) garciacubasi Shasky, spec. nov. Holotype, X 3.4 Figure 6: Glyphostoma (Gly phostoma) myrae Shasky, spec. nov. Holotype, X 3.4 Figure 7: Kurtziella (Rubellatoma) powelli Shasky, spec. nov. Holotype, X 7.8 Figure 8: Agathotoma (Vitricythara) klasmidia Shasky, spec. nov. Holotype, X 8.6 Figure 9: Agathotoma (Vitricythara) secalis Shasky, spec. nov. Holotype, X 7.0 Figure 10: Pyrgocythara emersoni Shasky, spec. nov. Holotype, X 6.2 Vol. 14; No. 1 THE VELIGER Page 71 third with about 30 axial riblets; the last Y of the third nuclear whorl rendered faintly cancellate by 4 to 5 distant spiral threads; axial sculpture of postnuclear whorls of rather strong antisigmoid ribs which number about 17 on the penult and from 15-20 much weaker ribs on the body whorl; the ribs of the body whorl are not angled, while the ribs of the other whorls are slightly angled at the periphery on an occasional specimen; spiral sculpture of about 15 fine threads, which increase to about 40 on the body whorl; suture distinct; aperture ovate; anterior canal very short; outer lip thin, smooth within, columella smooth and curved sigmoidally; anal sinus exceedingly shallow; color buff with a subsutural pale brown band and 2 wider brown bands on the last whorl; columella stained with brown. Dimensions of holotype: height 5.1 mm, diameter 2.0 mm. Type Locality: Holotype and 24 paratypes, at low tide, Agua de Chale, Baja California, 30°42’ N, 114°41’ W. 18 specimens making trails on sand bar, leg. Donald Shasky, May 3-6, 1962; 1 specimen, leg. Helen DuShane, May 20-23, 1966; 2 crab specimens, leg. Donald Shasky, No- vember, 1963; 4 crab specimens, leg. Donald Shasky, May 23, 1966. Type Material: Holotype, LACM 1574, 1 paratype, LACM 1575, single paratypes, AIM, AMNH, ANSP, CAS, SDMNH, SU, USNM, DuShane collection, 15 para- types, Shasky collection. Referred Material: Shasky collection: 1 specimen, San Felipe, Baja California; 1 specimen, Puertocitos, Baja Cal- ifornia; 1 specimen from shrimp trawler off state of Chia- pas, Mexico, December, 1962. DuShane collection: 6 specimens, Puertocitos, living on sandbars. LACM 70-11, 1 specimen from siftings, west side, Punta Ancon, Ecua- dor. Discussion: This little shell is best found at night. Its trail is so small that only a faint shadow is cast, which in bright sunlight is very difficult to see. Kurtziella powelli is quite different from other Kurtziella species from the same province. It has more than double the number of axial ribs and spiral threads of the species described to date. The ribs are not angled on the body whorl and only slightly so on the other whorls and then only in some specimens. It is my pleasure to name this species for Dr. A. W. B. Powell of the Auckland Institute and Museum. 8. Agathotoma (Vitricythara) klasmidia Shasky, spec. nov. (Figure 8) Description: Shell small, turreted, whitish with about 614 whorls; nucleus of 214 turns, the first 114 smooth, the last with about 20 faint axial riblets that are angled at the periphery; postnuclear whorls, except the body whorl, shouldered below the submerged and indistinct suture; axial sculpture of 11 antisigmoid, rounded ribs that ex- tend from suture to suture; major and minor fimbriated spiral threads cover the postnuclear shell; on the penult whorl there are 2—3 major threads and about 13 minor threads; on the body whorl there are about 40 threads of which about 10 are major; aperture long, oval; outer lip varicose with spiral threads reflected over the varicose portion; outer lip smooth within; columella straight ex- cept for a slight ripple; anterior canal short, open; anal canal open and with moderate callus. Dimensions of holo- type: height 5.0 mm, diameter 1.9 mm, height of aperture 2.5 mm. Type Locality: Holotype and 93 paratypes (all dead specimens) from 16-20 m, in mud, about | mile offshore, Olas Altas Bay, Mazatlan, Sinaloa, Mexico, 23°11’45” N, 106°27'00” W. Leg. Donald Shasky, December 23, 1962. Type Material: Holotype, LACM 1576, 3 paratypes, LACM 1577, 2 paratypes each to AIM, AMNH, ANSP, CAS, SDMNH, SU, USNM, remainder in Shasky and DuShane collections. Referred Material: Shasky collection: 2 crab specimens, SE side of Chivos Island, Mazatlan; LACM, | specimen dredged at Puertocitos, Baja California; Poorman collec- tion, 2 specimens, 31 m, Guaymas, Sonora, Mexico; LACM 65-21, 1 dead specimen, 9-27 m, Otoque Island, Panama Bay. Discussion: Combined with that of the next species. 9. Agathotoma (Vitricythara) secalis Shasky, spec. nov. (Figure 9) Description: Shell small, elongate, whitish, of about 4 whorls exclusive of the lost nucleus; axial sculpture of 1] rounded ribs that extend from suture to suture; ribs separated by rather deep sulci; ribs interconnected and overridden by spiral threads with resultant minute bead- Page 72 ing of the ribs and shallow rectangular pits in the sulci; there are 8-12 major spiral threads on the penult and 21-24 on the body whorl; 3 minute minor threads be- tween the major threads of the body whorl; whorls shoul- dered on first 3 whorls so that the suture is easily distin- guished, but shouldering disappears on the body whorl, and suture becomes less distinct; aperture long, narrow; outer lip varicose, coarsely crenulate, smooth within; columella smooth, straight; anterior canal short, open; anal callus thick; anal canal rounded, but with a very narrow slit at the opening. Dimensions of holotype: height 7.0 mm, diameter 2.3 mm, height of aperture 3.5 mm. Type Locality: Holotype and 11 paratypes (all dead speci- mens) from 16—22 m in mud, about | mile offshore, Olas Altas Bay, Mazatlan, Sinaloa, Mexico, 23°11’45” N, 106° 27’ W. Leg. Donald Shasky, December 23, 1962. Type Material: Holotype, LACM 1578, single paratypes, AMNH, SDMNH, SU, 2 paratypes, Shasky collection, 5 paratypes, DuShane collection. Referred Material: LACM 65-21, 2 specimens, 9-27 m, Otoque Island, Panama Bay. Discussion: A gathotoma secalis is a longer, narrower spe- cies than A. klasmidia. Both have eleven ribs, but those of A. secalis are beaded. ‘The spiral threads of A. klasmidia are fimbriated and more numerous. The opening into the anal canal of A. secalis is a narrow slit, while A. klasmidia has no constriction. The columella of A. klasmidia is faintly rippled while that of A. secalis is smooth. The name is derived from the Latin secale, meaning rye, the shape suggesting a grain of rye. A single specimen, that I collected at Venado Island, Panama, in March, 1971, after the above description was typeset, has a nearly perfect nucleus which is 3 whorled. The first whorl is smooth; the second with many faint axial riblets, and the third with fewer but stronger riblets and 3 faint spiral threads. THE VELIGER Vol. 14; No. 1 10. Pyrgocythara emersoni Shasky, spec. nov. (Figure 10) Description: Shell large for the genus, whorls 8; nuclear whorls 2, the first smooth and flat-topped, the second with about 30 axial riblets; a noded spiral carina appears on the last % of the second nuclear whorl; early postnuclear whorls with 9 rounded, sharp edged, antisigmoid ribs decreasing to 7-8 on the body whorl; ribs centrally noded with an intersecting weak spiral keel; other spiral sculp- ture of distant incised lines, except on the base where there are 8 cords; suture an undulate groove; aperture elongate; columella smooth; outer lip varicose, smooth within except for a single denticle just abapical to the wide, uncallused, unconstricted anal notch; anterior canal short, open; color of 3 distinct bands, a buff band on the upper portion of the whorl, a white band centrally and a light chocolate brown band above the suture, and the base of varying shades of buff. Dimensions of holotype: height 7.8 mm, diameter 3.2 mm. Type Locality: Holotype and 12 paratypes from under rocks, Agua de Chale, Baja California, 30°42’ N, 114°41’ W. All but 1 are crab specimens. Leg. Helen DuShane, May 1962 and May 1966. Type Material: Holotype, LACM 1579, | paratype, LACM 1580, single paratypes, AMNH, CAS, Shasky col- lection, 8 paratypes, DuShane collection. Referred Material: Intertidal crab specimens from the Gulf of California as follows. DuShane collection: Puer- tocitos and Guaymas; Shasky collection: San Felipe; LACM: San Luis Gonzaga Bay and Puerto Penasco. Discussion: Pyrgocythara emersoni is one of the largest species within the genus. P. emersoni seems closest to P. melita (Dall, 1919). P. melita is smaller and thinner, has more pronounced spiral sculpture, and has purple mark- ings. It is my pleasure to dedicate this lovely little shell to Dr. William K. Emerson of the American Museum of Natural History, New York. Vol. 14; No. 1 THE VELIGER Page 73 A Rheotaxic Study of aAVee Gastropod Species THOMAS M. DUCH Science Department, Bennett College, Millbrook, New York 12545 INTRODUCTION THE OBJECTIVE OF THIS STUDY is to compare aspects of rheotaxic behavior of three gastropod mollusks of the superfamily Trochacea: two turbinids, Leptothyra candida (Pease, 1868) and L. verruca (Gould, 1845), and a trochid, Euchelus gemmatus (Gould, 1845). The rheotaxic behavior of mollusks has been investi- gated by Arty & Crozier (1919), Crozier (1921), FEDE- riGHI (1929), Howes & WeEtts (1934), Neat (1965), NEWELL (1958), OverHoLSER (1964), and no doubt others; but there are no comparative studies of two or more tropical species. The importance of water currents in the lives of these gastropods is discussed. Since the gastropods of this study live in the intertidal zone where they are subjected to water currents it is assumed these factors are significant features in their general orientational behavior pattern. The currents in which and to which these gastropods orient appear to be produced primarily by two factors: (1) tidal changes and (2) waves. The three gastropods appear to orient themselves to the effect of stimuli such as water currents (pe“4ap = cur- rent) in two ways: (1) by a directed orientation reaction (taxis) in which the direction of motion of the gastro- pod is influenced by the stimulus and (2) by an undirected locomotory reaction (kinesis) in which the average speed, the average rate of turning, etc. of the gastropod, but not the direction in which it moves, are dependent upon the stimulus. The definition of taxis used by Partak (1953) is a more general definition than that commonly used, 1.¢., “that the gastropod’s motion is directly toward or away from the source of the stimulus, in that it also includes the term ‘transverse reaction, which means the gastropod moves at an angle to the line joining it to the source of the stimulus.” THe EXPERIMENTAL ANIMALS The trochid Euchelus gemmatus and the turbinids Lepto- thyra candida and L. verruca are anatomically similar trochacean gastropods. The differences between the troch- id and the two turbinids are associated with aspects of external organisation which superficially at least are dif- ficult to relate to habitat or to link with function (Gra- HAM, 1965). The trochids are distinguished from the conchologically similar turbinids by the type of opercu- lum: in the trochids it is thin and horny, in the turbinids thick and calcareous. The conchological similarities among the 3 species of trochaceans afforded a basis of comparison in the rheo- taxic experiments, for slight behavioral variations then could be more easily observed in similar animals. GENERAL ENVIRONMENT The trochaceans studied are readily available as common intertidal species in the Hawaiian Islands. These areas are characterized by tide pools and shallow waters of moder- ate turbulence where there is some swirling and splashing of water. The trochaceans are found on surfaces which are generally level, but which have an undulating microtopo- graphy because of depressions and rock outcrops. The trochaceans are specifically found on the lower ? of rocks which have at least one flat vertical or horizontal surface and have a dark mottled appearance. These surfaces oc- cupied by the trochaceans are in such a position with respect to water currents that tiny particles of sand or silt do not accumulate on the animal while it is clinging to a surface. Although the trochaceans are able to cling to the surfaces, they accumulate in the less-exposed places, often congregating in crevices, beneath stones or among algae (specifically species of Cladorpha, Padina, and Schizothrix). The trochid and the turbinids apparently occur in slightly different areas, Euchelus gemmatus in crevices or beneath algae on the upper part of rocks and Leptothyra verruca and L. candida on the lower part of the rocks. An apparent increase in the activity of the trochaceans occurs about sunset. In spite of the fact that the gastropods can be seen feeding throughout the day, “vigorous” feed- ing and activity seem to occur more at twilight. MATERIALS anp METHODS From preliminary and general observations of the trocha- ceans over a period of two years, investigations were ex- Page 74 panded to include the following: (1) an investigation of a positive or negative rheotaxis; (2) an investigation of the angle of orientation to a current of water; (3) an investigation of the orientation during rising and falling tides; and (4) determination of the physical effects of water currents on the orientation of an empty trochacean shell. The following methods and materials were utilized for each of the investigations: (1) all experimental ani- mals were acclimated for one day before use in an experi- ment; (2) the temperature of all apparatus was main- tained at between 20 and 25° C; (3) filtered sea water was used in all experiments; (4) all experiments were done in each of the tidal periods of the day except those occurring between 12:30 a.m. and 8:30 a.m.; (5) be- fore each trial an apparatus was horizontally leveled to limit the possible influence of a geotaxic response; (6) all apparatuses were shielded with black paper to limit the influence of reflected light; and (7) after each trial the apparatus was cleaned to prevent the possible influence of an old mucus trail on the behavior of the trochacean. An INVESTIGATION orf a POSITIVE or NEGATIVE RHEOTAXIS In the field the three species of trochaceans are usually oriented toward the incoming tide. This observation sug- gested the possibility of a positive rheotaxic response as a mechanism which would maintain this position, the troch- aceans receiving a stimulus from the incoming tide. To test the hypothesis that the trochaceans orient and move against a directed current of water, thus exhibiting positive rheotaxis, a current tube was designed in which the intensity of the water current was easily regulated by fluctuating the height of the water supply. Twenty ani- mals of each species with shells about 2 mm in diameter were individually subjected to the current tube. The tube was filled with water and then an animal was placed so that its anterior (apertural) end would be opposite the current. A current of water (28 ml/sec, a possible thresh- old stimulus) was released after the animal was firmly attached to the substrate. The animal’s response was termed positive if it turned and moved horizontally one centimeter against the direction of the water current. An INVESTIGATION or tHe ANGLE oF ORIENTATION To a CURRENT or WATER Both in the laboratory and in the field, there seems to be an angular deviation in the path of movement of a trocha- cean when there is either an increase or decrease in the rate of water current. THE VELIGER Vol. 14; No. 1 A “movable” protractor was designed to test the hypo- thesis that the angle of orientation of the snail changes with a change in intensity of a water current. An animal was placed so that its anterior end (aperture) would be subjected to a directed water current, a stimulus of the effect (angular response), which was released from a glass pipet after the animal was firmly attached to the sub- strate. The angles of orientation (responses) of 20 indi- vidual animals each of Euchelus gemmatus and Lepto- thyra verruca were measured in separate currents of water (28 ml/sec; 50 ml/sec; 80 ml/sec; 90 ml/sec; 165 ml/sec;and 200 ml/sec). The components of the measured angles consisted of the direction of the water current and the axis of the snails’ shells. DETERMINATION or tHe PHYSICAL EFFECTS or WATER CURRENTS In THE ORIENTATION OF THE TROCHACEAN SHELL It is easily observed that a coiled turbinate shell sealed by an operculum is posturally unstable in directed water currents. This observation suggested that the physical ef- fects of water currents on the animal’s shell may be related to the position of the animal in water currents. It then appeared worthwhile to investigate the possibility that the angular deviation of an empty trochacean shell in a known water current might approximate the angular orientation of a trochacean in the same current intensity, thereby implying that the hydrodynamic qualities of the snail’s shell may be important as possible receptors associ- ated with the rheotaxic response. To test the hypothesis that the angular orientation of an empty trochacean shell may be proportional to the intensity of water current, 50 shells of each species were individually subjected to various water currents (30 ml /sec; 50 ml/sec; 100 ml/sec; and 150 ml/sec). A shell was placed on an apparatus essentially the same as that for the experiment measuring a trochacean’s angle of orientation in a current of water, but a wax mount was added on which the empty shell was set. The wax mount was shaped to simulate the foot of the animal and mounted upon an easily rotated glass plate. An INVESTIGATION or ORIENTATION DURING RISING anp FALLING or tHE TIDES While observing the 3 trochacean species in the field, the vertical movements of Euchelus gemmatus appeared cor- related with the changing tides as opposed to the lack of Vol. 14; No. 1 THE VELIGER Page 75 tidal vertical movements of Leptothyra verruca and L. candida. An experiment was designed to investigate the relation- ships between the vertical movement of Euchelus gemma- tus and breaking waves and turbulence during the lower- ing and rising of tides. Forty animals were placed in separate containers of 1 gallon capacity: 20 into a tideless aquarium and 20 into an aquarium that was vigorously aerated for the duration of the entire experiment. Each apparatus was divided into an A zone and a B zone by a horizontal line midway up the container. The selected tidal periods represented the higher and lower tides (extreme conditions) in a month: in this case 14 tidal periods between 1.4 and above and 16 tidal periods ranging between 0.0 and below. A measurement was taken at each preselected tidal period by counting the number of animals present in areas A and B. RESULTS The 3 species show a positive rheotaxic response to water currents of above 27 ml/sec. A comparison of the 3 spe- cies, however, shows a distinct difference in the time re- quired to move horizontally 1cm in the water current. Euchelus gemmatus moves faster than either of the 2 turbinids, while Leptothyra verruca moves faster than L. candida. Water currents of intensities other than 28 ml/sec resulted in observations suggesting that the rate of move- ment might be directly proportional to currents below 28 ml/sec and inversely proportional to water currents of 50 ml/sec; 100 ml/sec; and 156 ml/sec. There appears to be a relationship between the distance moved per second by the animal and the speed, and therefore the resistance provided by the various water currents. The average speed of forward movement of the trochaceans steadily increases for a period and appears to reach a maximum in a water current of 30 ml/sec. The speed then steadily decreases, presumably to the point where the resistance of the water current cannot be over- come. From the data it appears that the animals are all maximally stimulated by water currents of 20-30 ml per second. The steady decrease and finally stoppage of forward movement may be accounted for by the increas- ing resistance of the water current. While it is evident that the rate of movement of the animals is affected by the speed of the current, it must be remembered that the resistance to overcome is greater as the water current increases, and the animal must do more work as the resistance increases if its rate of progress is to be main- tained. When the resistance increases to a point which cannot be overcome, the snail maintains itself in a station- ary position at an angle of slightly less or more than 180° to the axis of the shell, remaining in this position for as long as 3 days. As soon as the intensity of the current is reduced the snail again begins forward movement. To the stimulus of the water current the snail showed an immediate reaction, which was a spasmodic response followed by the snail turning into the current. As the trochacean oriented with respect to the water current, it extended both tentacles, the right tentacle toward the direction of the oncoming current and the left tentacle waving from side to side. It is perhaps noteworthy that the trochaceans turn to the left in more than half of the angular orientations. The angular orientation of a trochacean to a current of water was first observed in a current of about 28 ml/ sec, a possible threshold of response. From the data it ap- pears that the angle of orientation decreases in propor- tion to increasing current intensity with a final result of dislodgement in currents above 200 ml/sec. The experi- ment showed a positive relationship between the directed current expressed as intensity of stimulation and the angle of orientation to the directed current (response). All of the empty trochacean shells were posturally unstable in experimental water currents of above 50 ml/sec and were consistently dislodged from the constructed wax foot, falling 80% of the time to the left. The distribution of the positions of the animals in zones A and B of the aquaria versus the preselected tidal periods provided results which implied that the vertical move- ments of Euchelus gemmatus might be correlated with tidal periods (70 - 90% of the snails were counted in the upper part of the container [zone A] during the preselec- ted tidal periods). The control aquaria (no currents) provided the same results, suggesting a possible endogen- ous rhythm. In water currents above 50 ml/sec the angular orien- tations of the empty shells were sharply decreased as the intensity of the water current increased. No quantitative proportional relationship was observed. DISCUSSION In comparing the rheotaxic behavior in the 3 species there appear to be behavioral differences between the trochid and the 2 turbinids, but no pronounced difference in rheotaxic behavior between the turbinids, Leptothyra candida and L. verruca. The general rheotaxic behavior of the trochaceans may be associated with their forward facing mantle cavity, shell shape, and possible endogenous rhythms. As Morton (1960) notes: “the forward facing mantle cavity in pro- sobranchs becomes the centre of those functions depending on the passage of a water current: respiration, olfaction, detection and removal of sediment, and in a few cases feeding as well.” When the animals are examined it is Page 76 THE VELIGER Vol. 14; No. 1 found that in the trochid and turbinid mantle cavities the inhalant water current enters the mantle cavity on the left side of the snail (CiarK, 1958) and according to Yonce (1947) detritus accumulation continues until the material drops off the back of the animal (the floor of the mantle cavity) and is discharged in the exhalant stream. Thus, water currents directed at the right side of the snail would tend to keep the waste material accumu- lated at or in the exhalant aperture. The trochaceans respond to water current stimulation, orienting in the water current and waste products are carried away in the water current. The general shape of the trochacean shell may be related to angular orientation, since the empty shells tended to fall to the left in directed water currents and the angular orientative sharply decreases with increased current intensity. The vertical movements of Euchelus gemmatus do not appear limited to the stimulus of water current since these movements also occur in tideless aquaria, suggesting that there may be a daily rhythm which limits activity to certain hours of the day and the tidal cycle. The obser- vations of this study are not in direct agreement with those of Korrinca (1947) who believes that periodicity is associated with rhythmical differences in water pressure or possibly current velocities, though the vertical move- ments in the field may indeed be somewhat related to water currents. It appears that rheotaxy and angular orientation in water currents are no more than responses to a series of stimuli, water current being the more pronounced stimulus. SUMMARY (1) All the snails in the study were positively rheotaxic in directed currents of water, but in swirling currents of water only 60% of the snails showed a positive rheotaxic response. (2) The rate of movement appears to be directly pro- portional to water currents below 28 ml/sec and inversely proportional at currents between 50 ml/sec and 150 ml/ sec. While in a water current there is a suggestion that the most stable position is a 180° angle with the anterior axis of the snail. If the direction of the water current to the axis of the animal changes there may be an angular orientation; that is, there appears to be a relationship between current intensity and angular orientation to a current. (3) Vertical movements during at least certain times of the year may be related to the phases of the moon. There also appears to be a rhythm between vertical move- ment spawning and tidal height with Euchelus gemmatus (Ducu, 1969). No such relationship was noted with the turbinids. ACKNOWLEDGMENTS I would like to acknowledge the advice and comments of Dr. E. Alison Kay, Dr. A. Bernatowicz, and Dr. S. Townsly. Literature Cited Arey, LEsuiE B. « W. J. Crozier 1919. The sensory responses of Chiton. Journ. Exp. Zool. 29: 157 - 260 (April 1919) Cxark, W. C. 1958. Notes on the mantle cavities of some trochid and turbin- id Gastropoda. Proc. Malacol. Soc. London 33: 57 - 64 Crozizr, W. J. 1921. On some problems of adaptation. V. The phototropism of Lima. Biol. Bull. 41: 102 - 105 Ducu, THomas M. 1969. | Spawning and development in the trochid gastropod Euchelus gemmatus (Gould, 1841) in the Hawaiian Islands. The Veliger 11 (4) : 415 - 427; 2 text figs. (1 April 1969) FEDERIGHI, H. 1929. Rheotropism in Urosalpinx cinerea. Biol. Bull. 56: 331 - 340 GRAHAM, ALASTAIR 1965. The molluscan stomach. ‘Trans. Roy. Soc. Edinburgh 27: 737 - 778 Howes, N. H. « G. P WELLS 1934. The water relations of snails and slugs. I. Rhythms in Helix pomatia. Journ. Exp. Biol. 11: 327 KorrincA, PIETER 1947. Relations between the moon and periodicity in the breeding of marine animals. Ecol. Monogr. 17: 347 - 381 Morton, JoHN Epwarp 1958. Molluscs. 23 text figs. NEALE, JoHN R. 1965. | Rheotactic responses in the marine mollusk Littorina The Veliger 8 (1): 7-10; 4 text figs. (1 July 1965) Hutchison Univ. Libr., London. 232 pp.; planaxis PHILIPPI. NEWELL, G. E. 1958. An experimental analysis of the behaviour of Littorina littorea (L.) under natural conditions and in the laboratory. Journ. Mar. Biol. Assoc. U. K. 37: 241 - 266 OverHOLSER, J. ALAN 1964. | Orientation and response of Tegula funebralis to tidal current and turbulence (Mollusca: Gastropoda) . The Veliger 6, Supplement: 38 - 41; 4 text figs. (15 Nov. 1964) PaTLak, C. S. 1953. | A mathematical contribution to the study of orientation of organisms. Bull. Math. Biophys. 15: 431 - 476 YoncE, CHARLES MAurRICE 1947. ‘The pallial organs in the aspidobranch gastropoda and their evolution throughout the Mollusca. Phil. Trans. Roy. Soc. London, B 232: 443 - 518 (22 April 1947) Vol. 14; No. 1 THE VELIGER Page 77 Reproduction of Scrobicularia plana Da Costa (Pelecypoda : Semelidae) in North Wales ROGER N. HUGHES Marine Science Laboratories, Menai Bridge, Anglesey * (2 Text figures) INTRODUCTION LitTLE INFORMATION has been published on sexual repro- duction in Scrobicularia. Pars-DA-Franca (1956) de- scribed the seasonal changes in the histology of the gonads throughout the year for a population in Portugal. Lesour (1938) fertilised the eggs artificially in the laboratory and reared the larvae which came from them to the early free-swimming stage. Stoprorp (1951) reported young spat on the Cheshire Dee in June and July; THAMpRUP (1935) found large numbers of spat during the summer months and Smit (1951) found occasional young of the ‘O’ group at the end of October in Danish waters. This paper presents information on seasonal development of the gonads, sex ratio, and spawning for a North Wales population of Scrobicularia. MATERIALS anp METHODS Monthly collections of 10 animals were made between December 1966 and December 1967 from the same small area of beach (Aber foreshore, Conway Bay, Caernarvon- shire). During the period of sexual activity weekly samples were collected. The soft parts were fixed in saline Bouin’s solution. After 24 hours the fixative was washed out with 70% ethanol and the specimens upgraded via ethanol and 2-epoxy ethanol. The visceral mass, embedded in Ester wax 1960, was sectioned transversely (4u.) at 3 equally spaced levels along the dorso-ventral axis. Nuclei were stained black with Heidenhain’s iron haematoxylin and the cytoplasm pink with xylidine ponceau, differ- entiating with phosphomolybdic acid. ™ Present address: Department of Zoology, University College of North Wales, Bangor, Caernarvonshire, Wales. RESULTS Development of the Gonads: Scrobicularia is usually gonochoristic, no hermaphro- dites being found among the 63 mature and developing animals investigated by histological methods. However, Pars-pA-Franca (1956) reports a maximum of 4.42% showing hermaphrodite condition in a Portuguese popu- lation. Unlike many other gonochoristic bivalves (e. g. Mercenaria mercenaria (Linnaeus, 1758), LoosaNnorr, 1937; Crassostrea virginica (Gmelin, 1791), LoosaNnorF & Davis, 1952), Scrobicularia plana (da Costa, 1778) is not protandrous. The gonads of fully ripe specimens of Scrobicularia ramify between the lobes of the digestive gland and are easily seen in this position on opening the shell valves. The colour of the gonad ranges from white to yellow- orange, but there is no correlation between colour and sex. However, the gonadial follicles have a different shape in each sex, those of the males being rather tubular and those of the females more rounded. As a result of this difference the male gonad has a distinctly different gross texture from the more granular-looking female gonad, and after a little experience it is possible to sex the fully mature animals by eye on opening the shell valves. In contrast to the findings of Pars-pA-FraNnca (1956), who claims that there was a preponderance of females in the summer, an approximately equal sex ratio was found among 200 animals examined in the above manner throughout the period of sexual activity (Table 1a). However, Paes-da-Franca’s samples that showed low numbers of males coincided with periods of spawning and contained a relatively large number of “undifferen- tiated” animals that had just emptied their gonads. Hence it is likely that it was difficult to recognize recently Page 78 Table 1 Tests of Significance for Departures of the Ratio of males: females of Scrobicularia from Unity la: Menai Bridge population (North Wales) Season oS 992 Total X2 d.f. Probability June-August 111 89 200 2.42 1 0.25 - 0.10 1b: Portuguese population (Pazs-pE-FrANcA, 1956) Season oo+ 9 ¢@ Total x2 d.f. Probability Undifferentiated Spring 108 108 216 0 1 1 (March-May) Summer 55 69 124 0.79 1 0.50-0.30 (June-August) spawned males among the undifferentiated animals, thus giving a bias to the apparent sex ratio. In Table 1b, the numbers of males and undifferentiated animals are com- bined and compared with the number of females by the X? test, giving a probability of 0.50 — 0.30, which supports the above suggestion that there is no true difference be- tween the numbers of males and females. Animals in North Wales mature during their second summer after settlement, corresponding to a shell length of about 20 mm (Hucue_s, 1970). Between October and March the follicles of Scrobicu- laria are empty except for a thin layer of primary germ cells round the periphery. During this stage it is impos- sible to sex the individuals, a condition also occurring in several other bivalve species, e. g., Macoma balthica (Lin- naeus, 1758) (LAMMENS, 1967), Ostrea virginica (Loos- ANOFF, 1942). This contrasts with species where the fol- licles always contain germ cells in a more advanced stage of development, e.g., Arctica (= Cyprina) islandica (Linnaeus, 1758), Mercenaria mercenaria (LOOSANOFF, 1953). Development of the gonads begins during April, and in the very early stages dense aggregates of primor- dial germ cells form and produce more follicle cells or primary germ cells. The early follicles of Scrobicularia are full of vacuolated follicle cells which probably con- tain most of the reserve nutrient material used for sexual development as in Mya arenaria Linnaeus, 1758 (CoE & Turner, 1938) and Macoma balthica (LAMMENS, 1967). Histological changes during ovogenesis and spermato- genesis were found to be similar to those described for many other gonochoristic pelecypods, e. g. Macoma bal- thica (LAMMENS, 1967). Ova freshly stripped from ripe females were examined under the microscope. Each ovum is surrounded by a thick, clear membrane perforated by a single micropyle THE VELIGER Vol. 14; No. 1 which possibly facilitates the entry of spermatozoa (Aus- TIN, 1965). The average diameter of the egg minus the membrane for 40 animals (10 eggs were measured from each animal) was 91.0u; standard deviation = 6.9y; the average diameter of the egg plus the membrane being 140.1; standard deviation —8.1y. Hence, the thick- ness of the membrane is about 25p. Examination of stained and sectioned material from 10 mature male animals revealed that the sperm heads were 20 - 22.5 long and the tails 40 - 50u long. After spawning the follicles still contain a few gametes which become reabsorbed by vacuolate follicle cells. The lumina of the follicles collapse and many of the follicles degenerate completely so that the gonad is reduced in size until it is confined to the area immediately round the alimentary canal. Spawning: All attempts at conditioning and inducing Scrobicularia to spawn in the laboratory failed (7. e., raising the tem- perature to 20° C by daily increments of 1° C and sup- plying fresh sediment from the field enriched with cultures of Tetraselmis, Phaeodactylum and Monochrysis, addi- tions of sperm suspensions, electric shock, leaving the animals in the air for several hours, injections of inor- ganic salts [e. g.. MnO.OH] into the mantle and adductor muscle). However, on 10 August 1967 several males that had been kept for 7 months in a tidal tank containing native mud to a depth of 20cm, were seen liberating spermatozoa. The tank was fitted with a self-priming siphon which caused alternate filling and emptying ap- proximately every 6 hours. The mud temperature at the depth of the animals was 15.9° C. Each animal protruded its exhalant siphon about 5 cm vertically above the mud surface and expelled a thin, milky stream. Often the spermatozoa were released in relatively large clumps which dispersed after 1 to 2 minutes in the sea water. One individual spawned in two 5-minute bursts, separated by a lapse of about 3 minutes. After the final acts of spawning, the siphon, which had been maintained in a rigid and fully distended condition throughout spawning, acquired a puckered appearance due to the relaxation of muscles in its walls and was withdrawn slowly over a period of about 15 minutes. A total of 15 animals out of 35 in the tank commenced and finished releasing spermatozoa within a period of 4 hour. Surprisingly, none of the 19 females in the tank were observed liberating ova, neither when the males were spawning nor in the next 4 hours, though examination the following day revealed mature gonads in all the females present. Vol. 14; No. 1 The Breeding Season: The limits of the breeding season were determined by recording the stage of development of the gonads as indicated by histological sections throughout the year. Figure 1 summarizes the data by plotting “gonad condi- tion” against time. “Gonad condition” is an index ranging from 0 to 10, obtained by giving each of the animals (10 per sample) an arbitrary score corresponding to the stage of their gonadial development. Gonads with empty follicles —0, very early development or late re- gression after breeding — 4, advanced development or immediate post-spawning condition = 2, and the fully ripe gonads = 1. Between October and March the gonads consist of empty follicles, proliferation of the primary germ cells beginning about mid-April. The gonads devel- op quickly throughout May and June, becoming fully mature by the end of June. Spawning occurs during July and August (spat of 1.5mm were recorded on 26 July 1967) and the gonads regress quickly in September until only empty follicles remain by October. DISCUSSION Pags-pA-FRANCA (1956) working with a population of Scrobicularia from the Tage estuary in Portugal found differentiated gametes in all months of the year except December. Her results, expressing the percentage of indi- 10 (Rao) 100 9 é 9 = i an = 8 é & 3 Bf Res ~6 0 2 ie) Gs} oe 50 © ine] é i wz (o) 4 = 3 \ 30 3 ! \ Oo 2 ‘ 20 5 fae \ 10 -& oe N be, (0) ol o——to—o ot ot 9 Eo (0) D> | PmAm y y Lh Ss) OunmD Figure 1 Seasonal Variation in Gonad Condition (see Text) @ -— author’s data © - data from a Portuguese population (PaEs-pa-Franca, 1956) THE VELIGER Page 79 viduals per sample with differentiated gametes are plotted in Figure 1. The highest numbers of mature males and females were found in March to April and June to Sep- tember. At each of these periods spawning had taken place. The second spawning period from June to Sep- tember coincides with that occurring in the North Wales populations, but the earlier spawning period does not occur on the Welsh coast and is probably due to the warmer climate of Portugal, allowing a quick recovery of gonad condition during February and March (Figure 1). Lamellibranchs show two main types of gonad develop- ment after spawning (LamMMeENs, 1967). In the first group, which spawn in response to temperature rise during the warmer months, the animals undergo a qui- escent or hibernation period with empty gonads, prolifer- ation of which occurs at the end of the winter or at the beginning of spring when the temperature of the habitat rises again and the food reserves are rapidly laid down. In the second group, sexual reserves are laid down in summer or autumn with a temporary levelling off during the winter, the animals spawning in the following spring or early summer. Scrobicularia belongs to the first group where a period of quiescence follows spawning and lasts throughout the winter. In British populations the quies- cent period is 3 months longer than that of the Portuguese animals which begin to develop gametes in January. This lengthening of the quiescent period is probably due to the colder British winters. It is interesting in this re- spect that a delay in sexual development of Macoma balthica in the Dutch Wadden Sea occurred in the severe winter of 1962/63 (LamMeEns, 1967). According to Ciay (1962) Scrobicularia ranges at least from Senegal (latitude 14° N) to Bergen (latitude 60° N). Published mean monthly temperatures at the sea surface (M. O. 527 1949, Cons. perm. int. Explor. Mer. 1955) are plotted for North Wales, Portugal, and latitude 60° N in Figure 2. Mean temperatures for the North Wales mud-flat at a depth of 10 cm are also shown. It can be seen in Figure 2 that the mud temperatures at a depth of 10 cm fall about the curve for sea-surface temperatures in North Wales obtained from published tables, although the mud is slightly quicker to respond to seasonal temperature changes and attains slightly higher and lower temperatures in summer and winter respectively. Gonadial development in the North Wales population of Scrobicularia commences in April when the mean sea- surface temperature is about 8° C and the mud temper- ature about 10° C. Since the mean sea-surface tempera- ture for inshore Portuguese waters seldom falls below about 14° C it is most unlikely that gonad development in Scrobicularia is limited by temperature at this latitude. Rapid maturation of the gonads of the Portuguese popu- Page 80 THE VELIGER Sea Surface Temperature ° C Dy PM Ao opel A Ss © N wD Figure 2 Seasonal and Latitudinal Variations in Environmental Temperatures @ - Mean monthly sea-surface temperature for North Wales (Cons. perm. int. Explor. Mer. 1955) © - Mean monthly sea-surface temperature for Portugal (Meteorological Office 1949) A - Mean monthly sea-surface temperature for latitude 60° N (Meteorological Office 1949) A — Mean weekly temperatures (measured during 1965 - 1967) for the North Wales mud-flat at a depth of 10 cm lation occurred during the minimum sea-surface tempera- tures in February and March, and the first spawning occurred long before the maximum summer temperature was reached. Comparing Figures 1 and 2 it seems that Scrobicularia requires temperatures of at least 10° C for gonadial development to occur. At latitude 60° N these temperatures are reached about 2 to 4 weeks later than in North Wales. Possibly, the time available for gonadial development (i. e., periods when the temperature exceeds 10° C) decreases with increased latitude until, just be- yond the geographical limits of the species, there is insuf- ficient time for complete maturation. It would be inter- esting in this respect to follow seasonal changes in gonad condition of Scrobicularia from the higher latitudes. Since Portuguese populations of Scrobicularia have 2 spawning peaks per year, their annual reproductive output is probably much greater than that of the British popula- tions of this species. Adaptation of metabolism to the degree of latitude often occurs in pelecypods (BuLLock, 1955), but it seems that Scrobicularia has been unable to adapt itself sufficiently to maintain the same repro- ductive output throughout its latitudinal range. Vol. 14; No. 1 SUMMARY 1. Scrobicularia plana is usually gonochoristic, no herm- aphrodites having been found among the 63 mature an- imals investigated. The colour of the gonads varies from white to yellow-orange, but is not correlated with sex. Since the gonads of males and females differ slightly in texture due to differences in the shape of the follicles, ripe animals may be sexed by an experienced observer on opening the shell valves. Animals become mature in their second summer after settlement, corresponding to a shell length of ca. 20 mm. An equal sex ratio was found in the breeding season. 2. Gametogenesis is similar to that described for most other bivalves. The ova, which are about 91 pu in diameter, are surrounded by a thick (ca. 254) clear membrane, perforated by a single micropyle. Spermatozoa mature in clumps within the follicles. The elongated sperm heads measure 20 to 25 wu in length and the tails 40 to 50 pw. 3. Several males were observed spawning in an aquarium on 10 August 1967. Each animal spawned over a period of about 15 minutes and liberated spermatozoa in clumps which dispersed after 1 to 2 minutes in sea water. None of the females present released any gametes in response to the spawning of the males. 4. Differentiation of the gonads commenced in April and spawning continued from June to August, after which the gonads quickly regressed and remained empty from Octo- ber to March. 5. The effect of latitude on reproductive behaviour is shown by the contrast between the British population of Scrobicularia studied in this paper and a Portuguese pop- ulation studied by Pars-pa-FrRANcA (1956), which had another, earlier spawning peak in March/April. In the North Wales population gonadial development commen- ces at about 10° C, spawning occurring at 15 to 16° C. Possibly the northern geographical limits of Scrobicularia occur where the summer temperature rises above 10° C for a sufficiently long period of time for complete matura- tion of the gonads to take place. ACKNOWLEDGMENTS I should like to thank Professor D. J. Crisp, F R.S., for several helpful suggestions in interpreting the results and in the preparation of the manuscript. The work was carried out under the tenure of a N. E. R. C. research studentship. Literature Cited Buttock, THEODORE HoLMEs 1955. Compensation for temperature in the metabolism and activity of poikilotherms. Biol. Rev. 30: 311 - 342 Vol. 14; No. 1 THE VELIGER Page 81 Cray, E. 1942. Seasonal gonadal changes in adult oysters, O. virginica, 1962. Literature survey of the common fauna of estuaries 11. of Long Island Sound. Biol. Bull. (Woods Hole) 82: Scrobicularia plana (pa Costa). Brixham, Devon (I. C. I. 195 - 206 Paints Div., Marine Res. Sta.). 8 pp. 1953. Reproductive cycle in Cyprina islandica. Biol. Cor, WesLey Roswe i « Harry J. Turner, Jr. 1938. Development of the gonads and gametes in the soft-shell clam (Mya arenaria). Journ. Morphol. 62: 91 - 111 Cons. Perm. int. Explor. Mer. Service Hydrographique 1955. Temperature and salinity at the surface of the North Sea and adjacent waters: Provisional monthly mean charts. Charlottensund Slot, Danemark Hucues, Rocer NEvILLE 1970. Population dynamics of Scrobicularia plana (da Costa) on an intertidal mud-flat in North Wales. Journ. Anim. Ecol. 39: 333 - 356 LamMMENS, J. J. 1967. Growth and reproduction in a tidal flat population of Macoma balthica (L.) Netherl. Journ. Sea Res. 3: 315 - 382 Lesour, Marie V. 1938. Notes on the breeding of some lamellibranchs from Plymouth and their larvae. Journ. Mar. Biol. Assoc. U. K. 23: 119 - 144 LoosanorF, Victor Lyon 1937. Seasonal gonadal changes of adult clams, Venus mer- cenaria (L.) Biol. Bull. (Woods Hole) 72 (3): 406 - 416 Bull. (Woods Hole) 104 (2): 146-155 LoosanorF, Victor Lyon & Harry Cari Davis 1952. Temperature requirements for maturation of gonads of northern oysters. Biol. Bull. (Woods Hole) 103: 80 - 96 M. O. 527 [Great Britain Meteorological Office Publication no. 527] 1949. Monthly sea surface temperatures of North Atlantic Ocean. Her Maj. stationary office, London PAES-DA-FRANCA, MarIE DE LOURDES 1956. | -Variacao sazonal das gonadas em Scrobicularia plana da Costa. Arch. Mus. Bocage 27: 107 - 124 Smut, E. L. B. 1944. The effects of ice winters on marine littoral faunas. Folio geogr. Dan. 2 Sroprorp, S. C. 1951. An ecological survey of the Cheshire foreshore of the Dee estuary. Journ. Anim. Ecol. 20: 103 - 122 Tuamoprup, H. M. 1935. Beitrage zur Okologie der Wattenfauna auf experimentel- ler Grundlage. Medd. Komm. Havunders 10 Page 82 THE VELIGER Vol. 14; No. 1 The Tidal Migration of Donax variabilis Say (Mollusca : Bivalvia ) WILLIAM J. TIFFANY III Department of Biological Science, The Florida State University, Tallahassee, Florida 32306° (2 Text figures) INTRODUCTION THE BEACH CLAM, Donax variabilis Say, 1822 is a bivalve that inhabits the intertidal zone of sandy beaches, ranging from Texas around the tip of Florida to the shores of the Carolinas (Appott, 1954). These clams have the ability to maintain large populations of individuals on wave- swept beaches because of their morphological and behav- ioral adaptations to this environment. Donax variabilis, commonly called the coquina, exhibits a stereotyped migration pattern in that it moves shore- ward and seaward with the flood and ebb tides. Previous investigators have dwelled mainly upon the mechanism of this tidal migration, and many hypotheses have been suggested to account for it in this and other species. Investigations of migration patterns were carried out by Mori (1938, 1950) on Donax semigranosis Dunker, 1877, in Japan. He proposed an “internal time clock” mechanism to be responsible for the migrational behavior. HepcpetH in 1953, however, was the first to publish ob- servations and theories concerning the tidal migration of D. variabilis. Coz (1955) and Ponto (1967) confined their studies to the general ecology of D. gouldii Dall, 1921, on the coast of California and Western Mexico. JAacoBsoN (1955) observed D. fossor Say, 1823 on Long Island, New York. LoEscu (1957) in his studies on the ecology of two species of Donax in Texas also mentioned the migration activity. TURNER & Betpinc (1957) hypothesized that the acoustic shock of waves breaking on the beaches initi- ates shoreward migration, and the seaward migration may be due to a “trigger and memory” mechanism which is activated at the changing of the tides. In 1959 EpcrEN observed D. variabilis at Clearwater Beach, Florida, and reported on the migrational activity. WADE (1964, 1965, ‘ Contribution number 5 from the Tallahassee, Sopchoppy & Gulf Coast Marine Biological Association. 1967a, 1967b) observed several species of Donax in the West Indies and set forth his migrational theories which are based on the acoustic shock stimulation concept. He classified the different zones of sandy beaches into 4 major regions: surf, wash, spray, and coast. The wash zone was further divided into saturated and unsaturated areas. The former is always covered by a thin slick of water, thereby completely filling the interstitial sand spaces. Farther landward, the unsaturated wash zone is covered by water from breaking waves, but it has no interstitial water because of drainoff to the lower beach regions. The other zones are self-explanatory. In the pres- ent study, Wade’s classification of zones is used when defining specific areas on the sandy beach. Donax variabilis occur predominantly in the saturated wash zone of the beach (see Figure 1). It is in this area that they are able to burrow due to the unpacked quality of the sand. In the unsaturated wash zone, the sand is = ————— Surf Zone {saturated} unsaturated | Spray Zone Coast Wash Zone AG GAGE Donax : Figure 1 Profile of a sandy beach (zonation nomenclature after WabDE, 1967a) Donax variabilis population represented by light area marked Donax. Vol. 14; No. 1 packed too tightly, and in the surf zone the boiling waters continually disrupt the sand, affording no foothold. Recently, ANSELL (1969), studying Donax incarnatus Sowerby, 1825 near Shertallai, India, comprehensively reviewed the existing literature on Donax migration. One of the unifying facts of all previous observations is that Donax usually responds to acoustic shock by exhibit- ing a jumping response. The coquinas emerge from the sand in response to any sharp shock, such as those from breaking waves or a blow from a shovel. WapE (1965) placed D. denticulatus Linnaeus, 1758 in a bucket filled with water and sand and observed the jumping in response to a sharp blow on the side of the bucket. Upon draining the water, the clams were unable to respond because the overlying sand was packed. MATERIALS anp METHODS The specimens used in this study were observed and col- lected at 3 principal sites on the Gulf Coast of Florida: Alligator Point, Franklin County; Siesta Key Beach, Sarasota County; Panama City, Bay County (Figure 2). The interrupted line transect method of sampling de- scribed by WapeE (1965) was used to determine the pattern of zonation in Donax variabilis. A line was laid down across the beach from the surf to the upper limits Figure 2 Collection sites of Donax variabilis in Florida AP-—Alligator Point; | PC — Panama City; SK — Siesta Key Beach THE VELIGER Page 83 of the sand, and comparative samples were taken at 20 cm intervals at right angles along this line. The sand bucket experiments of Wape (1965) were repeated at various phases of the tide to determine whether the jumping response was related to an intrinsic timing mechanism as well as to acoustic shock. The experiment was conducted with varying amounts of water in the bucket. Observations were made on actively migrating clams to determine whether or not they follow any specific pattern of transport from one area to another. Live clams were observed as they were transported by the wash and while burrowing into the sand. Preserved specimens were placed among migrating individuals and were observed to determine whether or not the living clams are passively oriented to the flow of water. The hypotheses of TuRNER & Betpinc (1957) and Mori (1938, 1950) were offered without experimental evidence. In order to test these hypotheses, I transported specimens of Donax variabilis from one site of collection to another and observed the resultant migratory behavior. The tides at the 3 principal collection sites are all differ- ent in nature. Those of Alligator Harbor are semi-diurnal. Panama City has a diurnal rhythm, and Sarasota experi- ences a mixed rhythm. The dates and tidal fluctuations are listed in Table 1. Table 1 Times of High and Low Water at Collection Sites in Florida Alligator Point Aug. 5, 1968 Aug. 6, 1968 Sept. 5, 1968 Sept. 9, 1968 high tide 0121 0209 0209 0327 low tide 0525 0637 0731 0955 high tide 1053 1209 1315 1603 low tide 1901 1955 2025 2213 Siesta Key Beach, Sarasota August 5, 1968 August 6, 1968 high tide 0834 0940 low tide 1808 1856 Panama City September 5, 1968 September 9, 1968 high tide 0841 0758 low tide 1958 2340 Approximately 5000 clams were transported from one collection site to another for each observation. The clams were taken from the sand, dried, and the valves were Page 84 THE VELIGER Vol. 14; No. 1 marked with black waterproof “Magic Marker.” The clams were then wrapped in polyethylene bags and put into a styrofoam cooler containing ice. By reducing the metabolic activity in this manner, the clams could be transported without supplying them with oxygen. At the site of observation, the clams were removed from the bags and placed in sea water until they resumed normal siphon- ing (usually about 15 minutes). They were then placed in the upper limits of the saturated wash zone to resume their migratory activity. Previous attempts to transport coquinas without cooling them resulted in a high mortality of individuals. However, those individuals that did survive the trips migrated with the indigenous clams (see Discussion), exactly as did the cooled clams. OBSERVATIONS anp DISCUSSION It was confirmed that acoustic shock is the cause of the jumping response exhibited by Donax variabilis. At all phases of the tide the specimens reacted when the bucket was struck. This was only true, however, if the bucket contained water above the level of the sand. When the water was drained, the clams no longer responded to the acoustic shock. This may be interpreted in two ways: either the sand was packed too tightly for the clams to emerge, or the interstitial water was not present to carry the shock wave to the clams. The latter possibility is the more probable of the two because the sand was not packed too tightly to prevent some of the clams from pushing to the surface (not a jumping response), when the water was drained. Similar emergence is also observed in nature, for if specimens are stranded in the unsaturated area of the wash zone, they may push themselves out of the substrate independent of any wave induced shock and may be carried seaward by the next downrush of water. This is in response to the water drainoff from the interstitial sand spaces and not to acoustic shock. In this case, the process of emergence is a gradual one, much different from the sudden jumping response exhibited when the clams are situated in saturated areas. The process of emergence is observed predominantly during ebbing tide. When the clams have reached their peak of ascent up the beach, the tide has already started to recede, moving the saturated wash zone seaward. Clams that were previously in saturated sand find themselves in un- saturated sand, and they emerge to the surface from which the wash of the waves carries them into saturated areas, thereby maintaining zonation within the saturated wash zone. The antero-posterior axis of Donax variabilis is oriented perpendicularly to the shore line during seaward or shore- ward migration. This orientation appears to be passive, for it is maintained in the case of the dead as well as the living clams. The dead clams, however, are completely at the mercy of the wash currents because they are not able to maintain zonation by burrowing. Eventually they are carried into the surf zone. A living clam, on the other hand, uses its muscular foot and protrusive siphons as effective braking devices. After being washed shoreward, living specimens extend the foot and siphons and begin to burrow into the sand at the onset of the backwash. This behavioral pattern is continued until the clams find themselves in unsaturated sand when the tide changes. At this time they respond to the drainage as described above. It must be remembered that the clams, even though they are in unsaturated sand, are still in the wash zone, and the shoreward extension of water from the breaking waves can effectively wash the clams seaward to the saturated area. According to TuRNER & BeLpinc (1957) Donax vari- abilis does not show specific zonation, nor do the individ- uals sort according to size. This is not the case with the coquinas at Sarasota, Panama City, or Alligator Point. Within the saturated wash zone a definite sorting pattern for size was observed. The smallest individuals are found at the top of the saturated wash zone (shoreward). ‘The animals get progressively larger toward the sea. The largest individuals are found in the surf zone. I found that these clams are not able to maintain their zonation because they are inactive and near death, as evidenced by the deteriorated condition of the body tissues, so they are washed passively into the surf zone. From the above observations, I conclude that the tidal migration of Donax variabilis is purely a phenomenon in which the animal responds to various physical stimuli in its environment independently of any endogenous mech- anism, if indeed it even exists. However, the following study of tidal variation was undertaken to test the hypo- thesis. On 5 August, 1968, clams were transported from Alli- gator Point to Siesta Key Beach, Sarasota. They were collected at 0545 when the tide was rising at Alligator Point. At 1130, while the tide in their normal environ- ment was still rising, they were placed on the beach at Sarasota during an ebbing tide. Within a few minutes the clams had burrowed into the saturated wash zone. Over the next 3 hours they migrated seaward with the ebbing tide, along with the Sarasota population. Obser- vations were suspended and again resumed at 1810. The Alligator Point population had become widely distributed Vol. 14; No. 1 laterally along the beach, but still maintained its position in the saturated wash zone with the indigenous clams. At this time the tide began to flood, and the clams started normal shoreward migration. The following day, Sarasota clams were transported to Alligator Point, leaving Sara- sota at 1000 during flood tide, arriving at 1600 during ebb tide. The Sarasota clams, which normally would be experiencing a rising tide, began migratory behavior in response to the new tidal pattern. The trips to Panama City involved less travel time than those to Sarasota and afforded more time to observe entire tidal fluctuations. On 5 September, 1968, at 0735, coquinas were collected at Alligator Point during flood tide and placed on the beach in Panama City at 0940 during ebb tide. The clams again migrated with the local individuals. At 1600, Panama City clams were transported to Alligator Point, arriving at 1815. The tide at both locations at this time was ebbing, and the clams migrated seaward. The final transplant of specimens was made on 9 September, 1968. Clams were collected from Panama City during flood tide at 0920 and carried to Alligator Point by 1250, also during flood tide. The clams from Panama City were observed throughout the next complete tidal change from high water at 1603 until low water at 2213. Night observations were made with the aid of lanterns and also indirectly by sampling the beach profile using the interrupted line transect method. The clams did not follow their original diurnal migratory pattern, but they migrated in accordance with the semidiurnal tide at Alligator Point. Since the transported coquinas migrated immediately with the indigenous population without a period of ad- aptation, an endogenous rhythm is unlikely. The experiments have shown that Donax variabilts re- sponds to acoustic shock by jumping into the uprushing water. The clams respond to the shock only if they are situated in the saturated wash zone. It is postulated that the interstitial water in this area carries the acoustic shock to the animals. Clams carried up the beach to the unsaturated wash zone are usually washed back into the saturated area before they have a chance to burrow under the sand, or else they uncover themselves, withdrawing foot and siphons, thus loosening their hold on the sub- strate and allowing themselves to be carried seaward. ACKNOWLEDGMENTS I wish to thank R. Winston Menzel for guidance and assistance in the present study and for evaluating the manuscript. I am also grateful for textual suggestions THE VELIGER Page 85 from the following people: Michael J. Greenberg, Wil- liam Herrnkind, and Sidney K. Pierce, Jr. I especially wish to thank Charles R. Stasek for critically reviewing this manuscript. Literature Cited Axsgpott, RoBERT TUCKER 1954. | American seashells. Princeton, New Jersey, D. van Nostrand Co., Inc.; xiv-+541 pp.; 100 text figs.; 40 plts. ANSELL, ALAN Davip 1969. Behavioural adaptations of intertidal molluscs from a tropical sandy beach. Journ. Exp. Mar. Biol. Ecol. 4: 9 - 35 Cor, WESLEY RoswELL 1955. Ecology of the bean clam Donax gouldi on the coast of southern California. Ecology 36: 225 - 229 Epcren, R. A. 1959. Coquinas (Donax variabilis) on a Florida beach. Ecology 40: 498 - 502 HepcPetH, Jort W. 1953. An introduction to the zoogeography of the north- western Gulf of Mexico with reference to the invertebrate fauna. Inst. Mar. Sci. 3: 110 - 224 Jacogpson, Morris KaRLMANN 1955. | Observations on Donax fossor Say at Rockaway Beach, New York. The Nautilus 68: 73 - 77 Lorscu, Harotp C. 1957. Studies of the ecology of two species of Donax on Mustang Island, Texas. Inst. Mar. Sci. 4: 201 - 227 Mort, SyvIt1 1938. Donax semigranosus Dxr. and the experimental anal- ysis of its behavior at the flood tide. Dobutsugoku Zasski a) (Ss oly 1950. Characteristic tidal rhythmic migration of a mussel, Donax semigranosus Dxr. and the experimental analysis of its behavior. Dobutsugaku Zasski 59 (4): 88 - 89 Pou to, Ross H. 1967. Aspects of the biology of Donax gouldi and a note on evolution in Tellinacea (Bivalvia). The Veliger 9 (3) : 330 to 337; 5 text figs. (1 January 1967) Turner, Harry J. « Davip L. BELDING 1957. The tidal migrations of Donax variabilis Say. Limnology and Oceanogr, 2: 120 - 124 Wane, Barry A. 1964. Notes on the ecology of Donax denticulatus (LINNE). Proc. Gulf and Caribb. Fish. Inst. 17th Annual Session: 36 - 41 1965. Studies on the biology of the beach clam, Donax (Bivalvia, Donacidae) in the West Indies. Doctoral thes. Univ. West Indies, Kingston, Jamaica; 271 pp.; 55 figs. 1967a. Studies on the biology of the West Indian beach clam, Donax denticulatus Linné. 1. Ecology. Bull. Mar. Sci. Gulf Caribb. 17: 149 - 174 1967b. On the taxonomy, morphology, and ecology of the beach clam, Donax striatus Linné. Bull. Mar. Sci. Gulf Caribb. 17: 723 - 740 Page 86 THE VELIGER Vol 12am Note on Feeding Habits of the Desert Snails Sphincterochila bowssiert Charpentier and Trochoidea (Xerocrassa) seetzeni Charpentier Y YOM-TOV ” Department of Zoology, Tel-Aviv University, Israel AND MARGALITH GALUN Department of Botany, Tel-Aviv University, Israel (1 Plate; 1 Table) INFORMATION ON THE COMPOSITION of the food consumed by the snails Sphincterochila boissiert CHARPENTIER, 1847 and Trochoidea seetzeni CHARPENTIER, 1847 has been obtained by field observations and by microscopic exam- ination of their digestive duct content and excrement. Sphincterochila boissiert and Trochoidea seetzeni are sympatric in vast areas in the Negev and Judean Deserts. The area studied is a transition zone between the area occupied by the Artemisietum herbae-albae Asso, 1781 association of the Irano-Turanian territory and the Zygo- phylletum dumosi BotsstEr, 1849 association of the Saha- ro-Arabic territory. The site selected was the slopes of two adjacent hills, one facing north and the other south. Here, Artemisietum herbae-albae inhabits the northern slope and Zygophylletum dumosi the southern one (FRIED- MAN, 1969). The Artemisietum herbae-albae association is accom- panied by Noea mucronata and Zygophyllum dumosum, whereas, accompanying the Zygophylletum dumosi associ- ation are Artemisia herba alba and Anabasis articulata. The Central Negev is a “true” desert; the annual rain- fall is approximately 100 mm, restricted to 10-25 days during the short winter season. Air and soil temperatures show considerable fluctuations. Soil temperature varies from at times, —3°C at winter night, to +70°C in summer at mid-day. The environmental conditions have 1 Part of a Ph. D. Thesis submitted to the Senate of the Tel-Aviv University been described more fully in a previous publication (Ga- LUN, 1960). The snails are active mainly during the winter season (November to April) and estivate from May to July. Activity recommences in August, September and October with appearance of night dew. There is dewfall approx- imately 10 nights per month. Aeolic sedimentation of loess soil is much higher on the slope facing north; on the south-facing slope there are many flint stones and the soil is more salty. Sphincterochila boissiert is a soil dweller. In the sum- mer it estivates and buries itself in the soil to a depth of 1-5cm (measured from the shell apex). Trochoidea seetzent live mainly on shrubs. These snails also estivate in the summer and attach themselves by their calcareous epiphragms to the shrubs at a height of 10 to 40 cm. On the slope facing south Trochoidea seetzeni settle mainly on Zygophyllum dumosum, occasionally on Arte- misia herba-alba. On the slope facing north, T: seetzent are found mainly on Noea mucronata (ForsKAL) AscH- ERSON & SCHWEINFURTH, 1887, and to a lesser extent on A. herba-alba and Haloxylon articulatum (CAVANILLES) Bunce, 1851. Reaumeria palestina Botsstrr, 1867 is used by them as substrate only after the plant is rinsed by rainwater. It seems that on the north facing slope T. seetzeni prefer Noea mucronata to other plants. The lichens in abundance on both slopes are Ramalina maciformis (DELILE) Bory, 1828 (always sterile), Calo- placa echrenbergii (Mixer, Argov.) ZAHLBRUCKNER, Vol. 14; No. 1 THE VELIGER Page 87 Table 1 Fodder remains found in the digestive duct and excrement of the snails Sphincterochila boissiert and Trochoidea seetzent Sphincterochila boissiert Spermatophyta: Tracheids = Fibers — Parenchyma Mesenchyma Bryophyta: Leaf cells of Dematodon convolutus Algae: Trebuxia sp. Blue-green ar ar Fungi: Hyphae Lichens: Buellia spores _ Soil particles aP ar Slope facing South Trochoidea seetzent Slope facing North South North + = ++ + Par tha — + + = + + = tt + + + + ++ = — + + + + + ++ ++ —_ — 1931 and Aspicilia sp. Telochistes lacunosus (RUPRECHT) Savicz, 1935 grows only on the slope facing north. Buellia canescens (Dickson) DENo anris is rare, and is found usu- ally without apothecia, on the south-facing slope; whereas the rocks on the north-facing slope are abundantly covered by fruiting B. canescens colonies. Buellia subalbula var. fuscocapitellata M. Lamp, 1936 is rare on the south-facing side and abundant on the north-facing one. The soil on the north-facing slope is matted by the moss Desmatodon con- volutus (HEepwic) Grout (FriepMAN, 1969). The digest- ive duct and excrement of both snail species contained plant particles as indicated in Table 1 and illustrated in Figures / to 6. Caloplaca ehrenbergu is the most common crustose lichen on both slopes. Teloschistes lacunosus also appears in quite large numbers on the northern slope. However, in no case were polarilocular spores, characteristic of these two lichens, found on microscopic examination in the material. On the other hand, apothecia with the brown two-celled spores (Figure 5) of the Buellias seem to be consumed in abundance, especially by Trochoidea seetzeni. It is of interest to note that whereas the Buellia do not contain any lichen acid, the apothecia of both C. ehrenbergu and Teloschistes lacunosus contain parietin. According to BACHMANN (1890), Stanx (1904) and ZuKAL (1896), lichens containing lichen acids are not eaten by animals. It might, therefore, be assumed that parietin functions, in this case at least, as a protective agent. It is not possible to identify the source of the Trebouxia cells and the fungal hyphae found in the digestive duct and excreta. However, the snails of the area examined have a choice between thalli devoid of lichen acids and thalli containing these substances in various forms. The blue-green algae (Figure 6) consumed by the snails are presumably free-living forms, since no blue- green alga lichens were found in this site. There is, so far, no way to relate the various tracheids (Figure 3), parenchyma (Figure 4) and fiber cells (Fig- ure /) to any particular plant on which the snails feed. Literature Cited BacHMAN, E. 1890. Uber nicht kristallisierte Flechtenfarbstoffe, ein Beitrag zur Chemie und Anatomie der Flechten. Jahrb. wiss. Bot. 21: 1-61 FRIEDMAN, J. 1969. The role of competition in desert plant communities. Ph. D. Thesis, Hebrew Univ., Jerusalem (in Hebrew). Gatun, MarcaLirH 1960. _A study of lichens of the Negev. Israel 9D: 127 - 148 Straw, E. 1904. Die Schutzmittel der Flechten gegen Tierfrass. Fest- schr. z. 70. Geburtst. E. Haeckel, Jena: 357 - 376 ZuKAL, H. 1895. | Morphologische und biologische Untersuchungen iiber die Flechten. Sitzgsber. Akad. Wiss., Wien 105: 1303 - 1395 Bull. Res. Council Page 88 THE VELIGER Vol. 14; No. 1 Plate Explanation Plant particles from the digestive duct and excrement of Sphincterochila boissieri and Trochoidea seetzent Figures 1a and rb: Fiber cells; a: 240; b: 100 Figures 2a and 2b: Leaf cells of Desmatodon convolutus. a: X120; b: 200 Figure 3: Tracheids; 750 Figure 4: Parenchyma cells; 150 Figures 5a and 5b: Brown, 2-celled spores of Buellia; a: 700; b: 1000 Figure 6: Blue-green alga; 750 THE VELIGER, Vol. 13, No. 4 [Yom-Tov « GaLun] - Figure 2b Figure zb Vol. 14; No. 1 THE VELIGER Page 89 New Species of Tropical Eastern Pacific Turridae JAMES H. McLEAN Los Angeles County Museum of Natural History, 900 Exposition Boulevard, Los Angeles, California 90007 AND ROY POORMAN ' 160 Sequoia Drive, Pasadena, California 91105 (2 Plates) INTRODUCTION A REVISED CLASSIFICATION of the eastern Pacific members of the family Turridae has been prepared by the senior author as a contribution to the forthcoming revised edi- tionof Seashells of Tropical West America, by Dr. Myra Kren. During the course of this review, a number of new species have been recognized in the avail- able collections. The new species are validated here for inclusion in the new edition, which is to be published during the summer of 1971. The 53 new species plus 10 described by Donald R. Shasky (1971) comprise approximately 25% of the total of 255 shallow water species of Panamic Province turrids entered in the text. Omitting the endemic species dis- cussed below from the Galapagos Islands, the percentage of new species in the fauna drops to 19%, still a rather high percentage. ‘There remain, in the collections at hand, about 20 species that are obviously new, but not described at this time, for lack of a fully mature specimen in good condition, or because some were recognized too late to be included in the book. Doubtless many more are yet to be found. Two considerations may help to explain this high per- centage of new species in a faunal province that is other- wise reasonably well known. First, the difficulty until now, of identifying previously described species of turrids be- cause of the general lack of good illustrations. With the exception of the effort by KEEN (1958) in the first edition, there are no recent attempts at compilation, the papers * Research Assistant in Invertebrate Zoology, Los Angeles County Museum of Natural History. dealing with the family consisting of descriptions of new species. Second, many of the species are truly rare in col- lections, the bulk of them occurring offshore rather than intertidally, and many of them are of seemingly limited distribution within the faunal province. The richness of the collections available to us has allevi- ated the difficulty arising from scarcity of material, while solutions to the problems encountered in dealing with the older species are discussed by McLEAN (1971). The Galapagos Islands are the type locality for 19 of the new species. One from the Gulf of California is recog- niced also at the Galapagos. Nine previously described species are endemic to the Galapagos and 7 are known to occur at the Galapagos in addition to the mainland. Of the total of 36 Galapagan turrids, the 28 endemics there- fore represent 78% of the species. Sources of the type lots of the new species are as follows: 20, Hancock Foundation Collection, 7 of which are from the Galapagos; 12, André and Jacqueline DeRoy, all from the Galapagos; 5, McLean on LACM field expeditions; 5, Shasky Collection; 3, Poorman Collection; 3, collection of the late George Willett in LACM; and one each from the California Academy of Sciences, Margaret Cunningham, Norman P. Currin, the late Howard Hill (collection at LACM), and Peter M. Oringer. In this collaboration the contributions of the junior author include the taking of all the photographs, prepara- tion of an early first draft on each of the new species, and help in the sorting of the LACM collection during the early stages of the entire project. The senior author is responsible for the generic allocations and preparation of the final draft. Page 90 THE VELIGER Vol. 14; No. 1 Repositories for type materials described herein are as follows: AHF, Allan Hancock Foundation, University of Southern California (gastropod collection on loan to LACM); AMNH, American Museum of Natural History, New York; ANSP, Academy of Natural Sciences, Phila- delphia; CAS, California Academy of Sciences, San Fran- cisco; LACM, Los Angeles County Museum of Natural History; MCZ, Museum of Comparative Zoology, Harvard University; SBM, Santa Barbara Museum of Natural His- tory; SDNHM, San Diego Natural History Museum; SU, Stanford University, Paleontological Museum; USNM, United States National Museum of Natural History. ACKNOWLEDGMENTS In the course of reviewing the turrids on the specific level we have had the assistance of numerous people through discussion, correspondence, or loan of specimens. We wish to acknowledge the help of the following: James O. Bailey, S. Stillman Berry, Kenneth J. Boss, Twila Bratcher, Rose Burch, George P. Cummings, Margaret Cunningham, Norman P. Currin, Anthony D’Attilio, André and Jac- queline DeRoy, Helen DuShane, William K. Emerson, Leo G. Hertlein, Myra Keen, Virginia O. Maes, Ann Marti, Ray Maynard, Joseph P. E. Morrison, Alice Mul- len, Axel A. Olsson, Peter M. Oringer, George E. Radwin, Mary Ricaud, Joseph Rosewater, Barry Roth, Donald R. Shasky, and Gale Sphon. We are particularly grateful to Dr. Myra Keen of Stan- ford University and Mrs. Virginia O. Maes of the Phila- delphia Academy of Natural Sciences for continual as- sistance in many ways through correspondence. Dr. S. Stillman Berry of Redlands, California, helped us with the derivation of names of classical origin. 1. Calliclava jaliscoensis McLean & Poorman, spec. nov. (Figure 1) Description of Holotype: Shell small for the genus, sur- face glossy, color pinkish white, most intense between the axial ribs at the periphery, back of last whorl with a faint orange flush; slender, length of aperture about % the length of the shell. Protoconch of 2 whorls, with a low carination from the start; postnuclear whorls 8. Axial ribs 7 on early whorls, increasing to 9 on penultimate whorl, obsolete on the shoulder and base but forming elongate nodes at the periphery; spiral sculpture of irregularly spaced striae, approximately 9 on the penultimate whorl, more deeply incised across the base; lip preceded by a slightly more prominent axial rib 4 turn back. Sinus deep, U-shaped, bordered by curved parietal callus on the in- side; lip edge nearly straight, stromboid notch well marked; anterior canal short, flexed to the left and deeply notched; columella slanted to the left; parietal wall and inner lip slightly raised. Height, 12.3, diameter, 4.1 mm. Type Locality: Tenacatita Bay, Jalisco, Mexico (19°17’ N, 104°50’ W), 20-40 fathoms, 18 February 1938, 8 speci- mens dredged by George Willett. Type Material: Holotype, LACM 1465, 1 paratype, LACM 1466, single paratypes, AMNH, ANSP, CAS, SDNHM, SU, and USNM. Referred Material: LACM, 7 lots, including Banderas Bay, Tenacatita Bay, Cuastecomate Bay, Mexico; Puerto Culebra, Costa Rica, 5-20 fathoms. Discussion: Smallest of the Calliclavas, specimens from the same lot may be deep pink, faintly pink, or white without a trace of color. It is the only species so marked and is readily distinguished from the others. The species is evidently common off the Mexican state of Jalisco, hence the name. 2. Calliclava lucida McLean & Poorman, spec. nov. (Figure 2) Description of Holotype: Shell of medium size for the genus; surface glossy, color flesh pink with irregular chest- nut mottling in the shoulder area; length of aperture about 4% the length of the shell. Protoconch large, 2 whorled, with a low carination from the start; postnuclear whorls 8. Axial ribs 9 on the early whorls, increasing to 14 on the penultimate whorl, extending diagonally across the weakly channeled shoulder from suture to suture, nearly obsolete upon the final whorl; spiral sculpture of broadly spaced striae, more pronounced upon the base; lip preceded by an axial swelling % turn back, broadly marked with chestnut color. Pillar constricted below the flat-sided profile, columella slanted to the left, callus slightly raised; sinus deep, U-shaped, bounded by curved parietal callus on the inside; lip not greatly thickened, stromboid notch of moderate depth; anterior canal short, deeply notched. Height, 16.0, diameter, 5.9 mm. Type Locality: Off Punta Gorda, southeastern Baja Cali- fornia (123°08’ N, 109°35’ W), 10-20 fathoms, 5 April 1966, 1 specimen dredged by James McLean on the R/V Sea Quest, LACM station 66-18. Type Material: Holotype, LACM 1467. Referred Material: LACM 66-17, 2 specimens, off Rancho Vol. 14; No. 1 Palmilla, Baja California; LACM 66-14, 1 specimen off Cape San Lucas, Baja California, 10-20 fathoms; CAS hypotype 12257, CAS locality 17691, 45 fathoms off Arena Bank, figured as “Clavus hecuba Dall,” (KEEN, 1958: 448; fig. 733). Discussion: Calliclava lucida is less strongly shouldered than most members of the genus and readily distinguished by its color pattern of brown mottling on pink. The name is a Latin adjective, shining or bright, with reference to the high gloss of the shell. 3. Calliclava rhodina McLean & Poorman, spec. nov. (Figure 3) Description of Holotype: Shell of medium size for the genus, dark pink, subsutural band yellow-brown; slender, length of aperture about % the length of the shell, suture impressed, shoulder rounded. Axial ribs 9 on early whorls, increasing to 14 on penultimate whorl, extending across the shoulder and base and becoming obsolete upon the pillar; axial sculpture of numerous fine striae, more broadly spaced and prominent upon the pillar; lip pre- ceded by a more prominent axial rib %4 turn back. Sinus deep, U-shaped, bounded by curved parietal callus on the inside; lip edge nearly straight, stromboid notch moder- ately deep; anterior canal short, slanted to the left and deeply notched; siphonal fasciole prominent, parietal wall broad, inner lip raised. Height, 20.3, diameter, 6.2 mm. Type Locality: Isla Grande Bay, Guerrero, Mexico (17° 42’N, 101°41’ W), 5 specimens collected by W. J. Sea- holm, 1940 or earlier. The type lot was given to the late Howard Hill of LACM, who retained 3 specimens and distributed 2 to CAS. Type Material: Holotype, LACM 1468, 1 paratype, LACM 1469, | paratype, USNM, 2 paratypes, CAS. Referred Material: CAS locality 17853, Tangola Bay, Oaxaca, Mexico, 13 fathoms, 2 specimens. Discussion: Calliclava rhodina has a shorter aperture in relation to the length of the shell than most of the Cal- liclavas and is distinctively colored, no other species being dark pink with a yellow brown shoulder. Although a com- plete protoconch is lacking on all 7 specimens, the short anterior canal and thickened axial rib on the back of the last whorl suggests allocation to Calliclava. The specimens from Tangola Bay show more pronounced beading at the sutural termination of the axial ribs. The name is Latin, an adjective meaning prepared from roses, with reference to the characteristic color. THE VELIGER Page 91 4. Calliclava subtilis McLean & Poorman, spec. nov. (Figure 4) Description of Holotype: Shell of medium size for the genus, white, with a faint pink tinge; length of aperture about 1% the length of the shell. Protoconch of 2 whorls with a low carination from the start; postnuclear whorls 8. Axial ribs 9 on early whorls, increasing to 13 on penul- timate whorl, extending across the swelling in the im- mediate subsutural area and the shallow channel below it, and extending across the base and pillar. Spiral sculp- ture evenly spaced, deeply incised, missing across the sub- sutural channel, but increasing in strength across the base and pillar; lip preceded by a massive axial swelling 13 turn back. Sinus deep, U-shaped, bounded by curved parietal callus on the inside; lip not greatly thickened, crenulated by the incised spiral sculpture, stromboid notch shallow; anterior canal short, deeply notched; columellar callus raised. Height, 14.6, diameter, 5.3 mm. Type Locality: Off Jicarita Island, Panama (7°12’30" N, 81°47'05” W), 24 fathoms, 20 February 1934, 5 specimens (2 immature) dredged by the R/V Velero, AHF station 240-34. Type Material: Holtotype, LACM-AHF 1470, 3 para- types, LACM-AHF 1471, 1 paratype USNM. Referred Material: AHF 451-35, 3 specimens, Secas Islands, Panama; AHF 244-34, 1 specimen, Bahia Honda, Panama, 12—35 fathoms. Discussion: Calliclava subtilis is smaller than C. craneana (Hertlein & Strong, 1951) and has more deeply incised spiral sculpture. Only C. alcmene (Dall, 1919) has sculp- ture as deeply incised, but that species is larger and has more numerous axial ribs. Maximum length at maturity is 16 mm; minimum length, 10 mm. The name is a Latin adjective meaning fine or precise, with reference to the regular order of the sculpture. 5. Elaeocyma amplinucis McLean & Poorman, spec. nov. (Figure 5) Description of Holotype: Shell of moderate size for the genus, pale flesh colored with axial markings of brown, surface glossy; aperture about 14 the length of the shell; suture not deeply impressed, shoulder weakly concave. Protoconch relatively large, 2 whorled, tip bulbous, slightly off center, second whorl with a low carination, postnuclear whorls 8. Axial ribs 8 on early whorls, in- creasing to 10 on penultimate whorl, rising to crests at Page 92 the periphery and extending weakly across the shoulder and base; spiral sculpture of a faint groove delimiting the shoulder and a more definite groove separating the body whorl and pillar. Sinus deep, U-shaped, bounded by mas- sive, curved parietal callus on the inside, nearly con- stricting the opening; lip edge nearly straight, slightly thickened away from the edge, stromboid notch well marked; anterior canal short, slanted to the left and deeply notched; parietal wall broad, inner lip raised. Height, 19.9, diameter, 6.6 mm. Type Locality: James Bay, Isla Santiago (Isla San Salva- dor), Galapagos Islands, Ecuador (0°12’ S, 90°52’ W), 30 meters (16 fathoms), 4 February 1969, 2 specimens dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1472; 1 paratype, De- Roy Collection. The paratype measures 23.2 mm in height, 7.5 mm in diameter. Discussion: Elaeocyma amplinucis is characterized by its large protoconch, distinctive color pattern and paucity of spiral sculpture. In having little spiral sculpture it sug- gests the genus Cymatosyrinx Dall, 1889, but that genus has an axial swelling in back of the lip edge, while Elaeo- cyma does not. The name means large nucleus. 6. Elaeocyma melichroa McLean & Poorman, spec. nov. (Figure 6) Description of Holotype: Shell of moderate size for the genus; pale flesh colored with irregular brown mottling on the shoulder and faint axial markings of brown across the body whorl, surface glossy; aperture about 14 the length of the shell, suture deeply impressed, immediate subsutural area inflated. Protoconch whorls 2, first whorl bulbous with a lateral tip, second whorl with a low carina- tion; postnuclear whorls 10. Axial ribbing broad and low, scarcely perceptible; on early whorls the shoulder is con- cave and the axial ribs nodulous on the lower half of the whorl; on later whorls the shoulder is inflated. Spiral sculpture of broadly spaced grooves, 1 delimiting the shoulder, 3 additional on the final whorl and 3 closely spaced, deeply incised grooves on the pillar; back of last whorl with some backward slanting crinkles especially strong at the periphery and behind the stromboid notch. Sinus deep, U-shaped, bordered by curved parietal callus on the inside; lip edge nearly straight, stromboid notch well marked, anterior canal short, deeply notched; parie- tal callus broad, inner lip not markedly raised. Height, 26.1, diameter, 8.7 mm. THE VELIGER Vol. 14; No. 1 Type Locality: North of Hood (Espafiola) Island, Gala- pagos Island, Ecuador (1°21’55” S, 90°40’05” W) , 20-40 fathoms, 28 january 1938, 1 specimen dredged by the R/V Velero, AHF station 814-38. Type Material: Holotype, LACM-AHF 1473. Referred Material: Galapagos Islands: AHF 183-34, 1 immature specimen, 50—70 fathoms, San Salvador Island; AHF 318-35, 1 immature specimen, 45 fathoms, Santa Cruz Island; LACM, | specimen, 44 fathoms, northern coast of Santa Cruz Island, DeRoy. Discussion: Elaeocyma melichroa differs from the Gala- pagan species E. amplinucis spec. nov. and E. splendidula (Sowerby, 1834) in having an inflated shoulder in mature specimens and less pronounced axial sculpture than either species. Ground color varies from nearly white to tan. The name means honey-colored, a Greek adjective. 7. Kylix contracta McLean & Poorman, spec. nov. (Figure 7) Description of Holotype: Shell of small to medium size for the genus; surface texture glossy, pinkish white, back of last whorl with a broad brown area; length of aperture plus anterior canal slightly less than 14 the length of the shell; periphery shouldered, subsutural band slightly in- flated. Protoconch of 2 whorls, first whorl bulbous with a lateral tip, second whorl with a strong carination; post- nuclear whorls 9. Axial ribs 9 on early whorls, increasing to 14 on penultimate whorl, beaded in the subsutural area, sharply marked across the body whorl, fading upon the pillar; a more prominent axial swelling precedes the edge of the lip % turn back, axial sculpture wanting on the back of the last whorl, except for the strong subsutural beading; spiral sculpture of regularly spaced striae not overriding the axial ribs, becoming more deeply incised upon the pillar. Sinus deep, U-shaped, bounded by curved parietal callus on the inside; lip thickened behind the edge, stromboid notch weak; anterior canal of moderate length, at an angle to the lip edge, deeply notched, inner lip not raised. Height, 15.1, diameter, 5.3 mm. Type Locality: Puerto Guatulco, Oaxaca, Mexico (15° 43’ N, 96°08’ W), 40-70 fathoms, 7 March 1938, 7 speci- mens dredged by George Willett. Type Material: Holotype, LACM 1474, 1 paratype, LACM 1475, single paratypes, AMNH, ANSP, CAS, SDNHM, USNM. Vol. 14; No. 1 Referred Material: 8 lots from Mexico in the combined LACM and AHF collections, including Tenacatita, Cu- astecomate, Petatlan and Tangola Bays; 15-40 fathoms. Discussion: This evidently common species varies from white to flesh colored, while the size is consistent. It has been confused with Agladrillia pudica, which is larger, with a noncarinate protoconch and longer canal. The an- terior canal of Kylix contracta is relatively short, a feature emphasized by the name, meaning shortened. 8. Kylix woodringi McLean & Poorman, spec. nov. (Figure 8) Description of Holotype: Shell of medium size for the genus, white; length of aperture plus canal 14 the length of the shell; periphery shouldered, subsutural band slightly inflated. Protoconch of 2 whorls, first whorl bul- bous with a lateral tip, second whorl with a strong cari- nation; postnuclear whorls 9. Axial ribs 11 on early whorls, increasing to 15 on penultimate whorl, beaded in the subsutural area, extending across the body whorl, fading upon the pillar; a more prominent axial swelling precedes the edge of the lip % turn back, axial sculpture subdued on the back of the last whorl, subsutural beading strong; spiral sculpture of numerous, deeply incised striae or raised cords, faint on overriding the axial ribs, more broadly spaced upon the pillar. Sinus deep, U-shaped, bounded by curved parietal callus on the inside; lip thickened behind the edge, stromboid notch weak; an- terior canal elongate, almost of the same length as the aperture, and at an angle to the edge of the lip, canal deeply notched; parietal wall smooth, inner lip scarcely raised. Height, 16.2, diameter, 5.5 mm. Type Locality: Off Jicarita Island, Panama (7°12’30” N, 81°47'05” W), 24 fathoms, 20 February 1934, 4 specimens (3 broken), dredged by the R/V Velero, AHF station 240-34. Type Material: Holotype, LACM-AHF 1476, 3 para- types, LACM-AHF 1477. Referred Material: AHF 244-34, 3 specimens, Bahia Honda, Panama; AHF 224-34, 3 specimens, Gorgona Island, Colombia, 10-35 fathoms. Discussion: Some of the specimens show a faint flesh- colored tint on the back of the last whorl. The near white coloration is shared only by K. panamella (Dall, 1908), a species with fewer, more deeply incised spiral striae. Of the Panamic species of Kylix, K. woodringi has the finest, most closely spaced spiral sculpture. We dedicate the spe- THE VELIGER Page 93 cies to Dr. Wendell P. Woodring of the U.S. Geological Survey, whose 1928 monograph on the Jamaican Miocene provided a base for understanding the new world ‘Tur- ridae. 9. Leptadrillia fmichorda McLean & Poorman, spec. nov. (Figure 9) Description of Holotype: Shell of medium size for the genus, surface dull white, aperture and rib interspaces pink; aperture plus canal slightly more than ¥ the length of the shell; suture distinct, shoulder only slightly im- pressed. Protoconch of 2 whorls, first whorl large and bulbous with lateral tip, second whorl with a low but sharp carination; postnuclear whorls 7. Axial ribs 8 on early whorls, increasing to 11 on penultimate whorl; ribs angulate, extending from suture to suture, slightly im- pressed and curved in the subsutural area, flattened across a shallow channel at the base of the body whorl; at the base of this channel is a spiral groove, below which the ribs are bent at nearly right angles toward the inner lip; back of last whorl with a thickened axial rib ¥5 turn back; spiral sculpture wanting. Sinus shallow, bounded on the inside by a curved parietal callus tubercle; lip edge thin, stromboid notch not apparent; anterior canal broad, weakly notched, inner lip raised. Height, 8.6, diameter, 3.1 mm. Type Locality: Cupica Bay, Colombia (06°39’ N, 77°31’ W), 12 fathoms, 26 January 1935, 1 specimen, grab sample by the R/V Velero, bottom sample station 548. Type Material: Holotype, LACM-AHF 1478. Referred Material: AHF 422-35, Port Utria, Colombia, | immature specimen, 20 fathoms; USNM 122800; Panama Bay, 1 specimen, 51 fathoms. Discussion: Leptadrillia firmichorda has a more strongly carinate protoconch and sharper axial ribbing than L. elissa (Dall, 1919). The latter species lacks the flexed ribbing upon the pillar that characterizes L. firmichorda. The name is a Latin noun derived from firmus—strong, and chorda—rope or twine, suggested by the strong axial sculpture of the species. 10. Syntomodrillia vitrea McLean & Poorman, spec. nov. (Figure 10) Description of Holotype: Shell of medium size for the genus; surface glossy, yellowish white, darker between the Page 94 axial ribs; aperture plus canal slightly more than 4% the length of the shell; suture deeply impressed, subsutural area not defined. Protoconch of 2 smooth whorls, first whorl bulbous with lateral tip; postnuclear whorls 7. Axial ribs 9 on early whorls, increasing to 11 on penulti- mate whorl, ribs rounded, extending from suture to su- ture but fading on the base before reaching the pillar; back of last whorl with a massive axial rib 14 turn back; spiral sculpture of evenly spaced spiral threading upon the pillar. Sinus broad and shallow, bounded on the in- side by a curved parietal callus tubercle; lip edge thin, stromboid notch shallow; anterior canal moderately elon- gate, unnotched; inner lip defined but not raised. Height, 6.2, diameter, 2.5 mm. Type Locality: Taboga Bay, Taboga Island, Panama (8° 47’ N, 79°33’ W), 2-5 fathoms, 24 July 1951, 2 specimens, collected by Helen Hoyt Crouch, AHF bottom sample station 346. Type Material: Holotype, LACM-AHF 1479, paratype, LACM-AHM 1480. The paratype is 9.2 mm in length and has 8 postnuclear whorls but does not have a mature aperture. Discussion: Syntomodrillia vitrea is the only known spe- cies of this otherwise Caribbean genus in the eastern Pacific. It resembles the type species, S. lissotropis (Dall, 1881), but is larger and has one or two more postnuclear whorls. The name means glassy, with reference to the surface texture. 11. Agladrillia badia McLean & Poorman, spec. nov. (Figure 11) Description of Holotype: Shell of medium to moderately large size for the genus; reddish brown, lighter colored on the pillar; length of aperture plus canal about 4% the length of the shell; suture deeply impressed, subsutural area concave, periphery shouldered. Protoconch of 3 smooth whorls, the tip small and immersed in the center; the first postnuclear whorl is carinate but nodulous with the emergent axial ribs; postnuclear whorls 8.5. Axial ribs 11 on early whorls, increasing to 15 on penultimate whorl, subdued in the subsutural area, extending di- agonally across the body whorl, obsolete upon the back of the last whorl, except for the subsutural beading; lip edge preceded by an axial swelling % turn back; spiral sculpture of regularly spaced, deeply incised striae that evenly override the axial ribs, more deeply incised upon the pillar. Sinus deep, U-shaped, bordered on the inside THE VELIGER Vol. 14; No. 1 by a parietal callus pad; lip edge not thickened, at an angle to the short, deeply notched anterior canal; inner lip slightly raised above the pillar. Height, 14.3, diameter, 4.8mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’S, 90°21’ W), 170-200 meters (93-110 fathoms), 26-29 July and 5 December 1969, 11 specimens, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1481, 2 paratypes, LACM 1482. Single paratypes, AMNH, ANSP, CAS, MCZ, SBM, SDNHM, SU, USNM. Referred Material: LACM, 2 specimens dredged by the DeRoys off the northern coast of Isla Santa Cruz; | speci- men off Daphne Minor Island, Galapagos, 70-80 fathoms (AHF 792-38). Discussion: Most of the paratypes are larger than the holotype (length to 20 mm), but in the larger specimens the last whorl has been injured and repaired. The holo- type is the only uninjured specimen. It may be confused with no other species, the deeply incised spiral sculpture and brown color are characteristic, hence the name, mean- ing brown. 12. Agladrillia flucticulus McLean & Poorman, spec. nov. (Figure 12) Description of Holotype: Shell moderately large for the genus; surface dull white, with a reddish brown band in the subsutural area and below the periphery, back of last whorl uniformly brown; length of aperture plus canal more than 14 the length of the shell; suture impressed, whorls rounded, subsutural area concave. Protoconch of 2% smooth whorls with a small central tip, first postnu- clear whorl carinate and nodulous with the emergent axial ribs; postnuclear whorls 10. Axial ribs 10 on early whorls, increasing to 22 on the penultimate whorl, sub- dued in the subsutural area, flexed across the body whorl and obsolete upon the base; back of last whorl with a mas- sive thickening % turn back, axial sculpture obsolete upon back of last whorl; spiral sculpture of numerous striae, slightly irregular in spacing, overriding the axial ribs and more pronounced upon the pillar. Sinus deep, U-shaped, bordered on the inside by curved parietal callus, lip slightly thickened away from the edge, at an angle to the moderately long, deeply notched anterior canal, inner lip slightly raised above the pillar. Height, 19.0, diameter, 7.2 mm. Vol. 14; No. 1 THE VELIGER Page 95 Type Locality: Gulf of Tehuantepec, off Puerto Madero, Chiapas, Mexico (14°24’N, 92°34’ W), 35 fathoms, 11 July 1963, 14 specimens, San Juan Expedition station W-1, collected by Donald Shasky. Type Material: Holotype, LACM 1483, paratype, LACM 1484, single paratypes, AMNH, ANSP, CAS, SDNHM, SU, USNM, 6 paratypes, Shasky Collection. Referred Material: Poorman Collection: 4 specimens, Rio Balsa, Sinaloa, Mexico; LACM: Banderas, Chamela, and Tenacatita Bays, Mexico, 15—40 fathoms, 5 specimens total. Discussion: Agladrillia flucticulus has more numerous axial ribs than the other species and a distinctive color pattern. It could only be confused with A. pudica (Hinds, 1843), a uniformly white species in which the back of the last whorl is dark reddish brown. The name is a Latin noun, meaning little wave, suggested by the fine, wavy axial ribbing. 13. Agladrillia gorgonensis McLean & Poorman, spec. nov. (Figure 13) Description of Holotype: Shell small for the genus; sur- face glistening white, back of last whorl faintly flesh colored; length of aperture plus canal more than % the length of the shell; subsutural area markedly concave, outline of whorls tabulate. Protoconch of 3 smooth whorls with a small central tip, first postnuclear whorl carinate and nodulous with the emergent axial ribs; postnuclear whorls 8.5. Axial ribs 8 on early whorls, increasing to 15 on the penultimate whorl, obsolete in the subsutural area and fading out upon the pillar; back of last whorl with a massive thickened rib ¥% turn back, axial ribbing obsolete on back of last whorl; spiral sculpture of evenly spaced, deeply incised striae, faint upon overriding the axial ribs, more pronounced upon the pillar. Sinus deep, U-shaped, bordered on the inside by curved parietal callus, lip edge thin, at an angle to the moderately long, deeply notched anterior canal, inner lip slightly raised above the pillar. Height, 11.0, diameter, 3.8 mm. Type Locality: North of Gorgona Island, Colombia (3°01’ N, 78°10'55” W), 40-60 fathoms, 24 February 1938, 3 specimens (2 immature), dredged by the R/V Velero, AHF station 854-38. Type Material: Holotype, LACM-AHF 1485, 2 para- types, LACM-AHF 1486. Discussion: Agladrillia gorgonensis is the only uniformly white species and is the only one characterized by the tabulate outline to the whorls. 14. Drillia (Drillia) cunninghamae McLean & Poorman, spec. nov. (Figure 14) Description of Holotype: Shell large for the genus; sur- face chalky white, colorless except for a narrow, faint brown line well below the periphery on the final whorl; aperture about ¥ the length of the shell; subsutural area markedly concave, outline strongly tabulate. Protoconch missing, postnuclear whorls 11. Axial ribs 7 on early whorls, increasing to 12 on penultimate whorl, obsolete on the shoulder, extending to the suture below on the early whorls, nodulous at the shoulder on the final whorl, but weak across the body whorl and obsolete upon the pillar; back of last whorl with an elongate rib subtending the sinus and a more massive rib % turn back; spiral sculpture faint on early whorls, consisting on the final whorl of numerous, unevenly spaced threads, more pro- nounced upon the pillar. Sinus deep, U-shaped, strongly outward projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch weak; an- terior canal scarcely defined, deeply notched; inner lip slightly raised above the pillar. Height, 37.9, diameter, 14.1 mm. Type Locality: Sonora, Mexico, in the vicinity of Kino and Agiabampo Bays, 10-35 fathoms, November 1963, 6 specimens, trawled by Captain Antonio Luna of Guaymas, Sonora, received by Margaret Cunningham. Type Material: Holotype, LACM 1487, 1 paratype, LACM 1488, 1 paratype USNM, 2 paratypes, Cunning- ham Collection, 2 paratypes, Poorman Collection. Referred Material: AHF 547-36, Angel de la Guarda Island, Gulf of California, 1 specimen. Discussion: Largest of the Drillias, characterized by the chalky surface and paucity of spiral sculpture. Drillia roseola (Hertlein & Strong, 1955) has similar proportions but is rose colored with a smooth surface and has fewer axial ribs. The species is named for Margaret Cunning- ham, now of Guaymas, Mexico, who kindly provided the type lot. 15. Drillia (Drillia) inornata McLean & Poorman, spec. nov. (Figure 15) Description of Holotype: Shell of medium size for the genus; surface chalky white, entirely colorless; aperture about ¥ the length of the shell; suture moderately im- pressed, undulating, immediate subsutural area swollen, Page 96 producing an inflated subsutural cord with a constricted channel below. Protoconch of 2% smooth whorls with small, immersed tip (paratypes), postnuclear whorls 11. Axial ribs 8 on early whorls, increasing to 10 on penulti- mate whorl, extending suture to suture on early whorls but stopping at the subsutural groove on mature whorls, narrowed and raised on passing from body whorl to pillar, obsolete upon pillar; back of last whorl with an axial rib subtending the sinus, preceded by a massive axial rib 4 turn back; spiral sculpture wanting. Sinus deep, U-shaped, strongly outward projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch weak; anterior canal scarcely defined, notched, inner lip slightly raised above the pillar. Height, 20.7, diameter, 7.8 mm. Type Locality: Off Puerto Refugio, Angel de la Guarda Island, Gulf of California (29°33’45” N, 113°30'47” W), 54-51 fathoms, 29 January 1940, 4 specimens (3 imma- ture), dredged by the R/V Velero, AHF station 1057-40. Type Material: Holotype, LACM-AHF 1489, 3 para- types, LACM-AHF 1490. Referred Material: 7 AHF lots, single specimens, in- cluding Tiburon Island, Espiritu Santo Island, Gorda Point, Clarion Island, Mexico; and Gulf of Dulce, Costa Rica, 20-69 fathoms. Discussion: Drillia inornata differs from the other Dril- lias in lacking spiral sculpture and having a swollen sub- sutural cord. The name is Latin, unadorned, with ref- erence to its absence of color and spiral sculpture. THE VELIGER Vol. 14; No. 1 16. Drillia (Drillia) sinwosa McLean & Poorman, spec. nov. (Figure 16) Description of Holotype: Shell of medium size for the genus, surface glossy, banded with reddish brown, most intense in the subsutural area and below the periphery, rib surfaces and pillar whitish; aperture about 4% the length of the shell, suture moderately impressed, whorls weakly inflated, subsutural area not demarked. Proto- conch of 2.5 smooth whorls, tip small, postnuclear whorls 9. Axial ribs 8 on early whorls, increasing to 10 on penulti- mate whorl, extending from suture to suture, flexed in the subsutural area, tending to be aligned from whorl to whorl during early stages, obsolete upon the pillar; back of last whorl with a slightly more prominent axial rib “4 turn back; spiral sculpture of numerous minute striae, visible under magnification. Sinus deep, U-shaped, not strongly projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch weak; an- terior canal scarcely defined, notched, inner lip flush with the pillar. Height, 20.3, diameter, 6.3 mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’S, 90°21’ W), 150 meters (82 fathoms), 10 June 1968, 1 specimen, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1491. Referred Material: DeRoy collection, 1 immature speci- men, 16.2 mm in length, dredged off northern coast of Isla Santa Cruz. Plate Explanation Note: All photographs are of the holotypes of the various new species; the authors in all cases are McLean « Poorman. Figure 1: Calliclava jaliscoensis X 3.6 Figure 2: Calliclava lucida X 2.7 Figure 3: Calliclava rhodina x 2.1 Figure 4: Calliclava subtilis X 2.9 Figure 5: Elaeocyma amplinucis x 2.2 Figure 6: Elaeocyma melichroa X17 Figure 7: Kylix contracta X 3.0 Figure 8: Kylix woodringi 2:7 Figure 9: Leptadrillia firmichorda x 5.1 Figure 10: Syntomodrillia vitrea X 6.6 Figure //: Agladrillia badia x 3.1 Figure 12: Agladrillia flucticulus X 2.3 Figure 13: Agladrillia gorgonensis x 4.0 Figure 14: Drillia (Drillia) cunninghamae x 1.2 Figure 15: Drillia (Drillia) inornata X 2.1 Figure 16: Drillia (Drillia) sinuosa X 2.2 Figure 17: Drillia (Drillia) tumida X 3.9 Figure /8a: Drillia (Drillia) valida, Holotype x 1.5 Figure 18b: Drillia (Drillia) valida, Paratype x 1.9 Figure 19: Drillia (Clathrodrillia) berryt x 1.9 Figure 20: Cerodrillia asymmetrica X 7.2 Figure 21: Splendrillia academica X 3.2 Figure 22: Splendrillia arga x 4.3 Figure 23: Splendrillia bratcherae X 3.6 Figure 24: Fusiturricula andrei x 1.4 Figure 25: Crassispira (Dallspira) martiae x 4.1 Figure 26: Crassispira (Striospira) coracina X 3.0 Figure 27: Crassispira (Monilispira) currant x 4.1 Tue VE icER, Vol. 14, No. 1 Figure 15 Figure 16 Figure 27 Figure 22 [McLEANn & Poorman] Figures / to 27 Figure 5 Figure 6 Figure 13 ef Figure 17 Figure 18a _—- Figure 18b eX Figure 23 Figure 24 Figure 25 Figure 26 Figure 7 Figure 14 Figure 27 Vol. 14; No. 1 THE VELIGER Page 97 Discussion: Drillia sinuosa differs from the other Drillias in having a more highly polished surface, less projecting sinus, and a distinctive color pattern. The name is Latin, full of windings, with reference to the flexed axial ribbing. 17. Drillia (Drillia) tumida McLean & Poorman, spec. nov. (Figure 17) Description of Holotype: Shell small for the genus, sur- face dull white; aperture 1 the length of the shell, suture impressed, undulating, subsutural area markedly concave, periphery strongly shouldered. Protoconch of 314 smooth whorls, tip small and immersed; postnuclear whorls 7%. Axial ribs 6 on early whorls, increasing only to 6% on mature whorls, lacking in the subsutural area, strong at the shoulder and across the body whorl; back of last whorl with a more prominent axial rib % turn back; spiral sculp- ture of evenly spaced spiral incisions, faint on early whorls, more prominent on penultimate and final whorl, deeply incised across the pillar. Sinus deep, U-shaped, strongly outward projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch moderately deep; anterior canal scarcely defined, deeply notched; inner lip strongly raised above the pillar. Height, 11.3, diameter, 4.4 mm. Type Locality: Banderas Bay, Jalisco, Mexico (approxi- mately 20°43’ N, 105°25’ W), 20-40 fathoms, 14 Febru- ary 1938, 33 specimens dredged by George Willett. Type Material: Holotype, LACM 1492, 24 paratypes, LACM 1493, single paratypes, AMNH, ANSP, CAS, MCZ, SBM, SDNHM, SU and USNM. Referred Material: AHF: Mexico, off Magdalena Bay (1032-40), off Tiburon Island (566-36), Concepcion Bay (682-37); Panama, Bahia Honda (248-34). Discussion: Some specimens of Drillia tumida show a faint pink tinge but most are uniformly white. It has the general proportions of D. roseola (Hertlein &, Strong, 1955), from which it differs in its much smaller size, presence of spiral sculpture, fewer axial ribs and less pro- nounced pink coloration. The Latin name means swollen, with reference to the massive axial ribs. 18. Drillia (Drillia) valida McLean & Poorman, spec. nov. (Figures 18a & 18b) Description of Holotype: Shell large for the genus, sur- face dull white, almost chalky, dark pink between the axial ribs; whorls nearly flat-sided, sutures not deeply impressed, aperture greater than 44 the length of the shell. Protoconch missing; early whorls with 10 axial ribs per whorl, increasing to 12 on the final whorl; ribs slightly impressed and flexed in the subsutural area, extending from suture to suture, narrowed upon the pillar and flexed toward the inner lip; lip not preceded by a thick- ened axial rib on the back of the last whorl; spiral sculp- ture of numerous fine striae, visible under magnification. Sinus deep, U-shaped, not strongly outward projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch shallow; anterior canal scarcely defined, deeply notched; inner lip raised above the pillar. Height, 29.3, diameter, 11.2 mm. Type Locality: Dewey Channel, near Cedros Island, outer coast of Baja California (27°42’07” N, 115°05’08” W), 49 fathoms, 27 February 1941, 1 specimen, dredged by the R/V Velero, AHF station 1259-41. Type Material: Holotype, LACM-AHF 1494, paratype, LACM-AHF 1495. The paratype (Figure 18b) is from San Jaime Bank, off Cape San Lucas, Baja California, 75 fathoms, AHF station 618-37. It has 10 postnuclear whorls, lacks a mature aperture and is missing the nuclear tip, but the second nuclear whorl is smooth, with no indica- tion of a carination. Discussion: Drillia valida differs from other eastern Pacific clavine species in having nearly flat-sided whorls. It does not have a thickened axial rib back of the lip that is characteristic in the genus. If there were evidence of carination on the protoconch it would be assignable to Elaeocyma, but the general facies suggests Drillia. The Latin name means stout or powerful, suggested by the massive appearance of the shell. 19. Drillia (Clathrodrillia) berryi McLean & Poorman, spec. nov. (Figure 19) Description of Holotype: Shell of small to medium size for the subgenus; surface glistening white with a faint reddish brown band in the subsutural area and another below the periphery, the swollen axial rib on the back of the last whorl also reddish brown; whorls rounded, the subsutural area faintly concave, aperture 43 the length of the shell. Protoconch of 3 smooth whorls, postnuclear whorls 10. Axial ribs 9 on early whorls, increasing to 12 on penultimate whorl, extending from suture to suture, but flexed in the subsutural area, strong across the body whorl and narrowed across the pillar; back of last whorl with a prominent axial swelling ¥ turn back; spiral sculp- Page 98 ture of numerous cords with slightly broader interspaces, cord surfaces glistening, interspaces dull white, cording more closely spaced in the subsutural area and more deeply incised upon the pillar. Sinus deep, U-shaped, markedly projecting, bounded by curved parietal callus; lip edge sinuous, stromboid notch shallow; anterior canal short, deeply notched; inner lip callus slightly raised above the pillar. Height, 23.3, diameter, 7.9 mm. Type Locality: Off Tovari, Sonora, Mexico (27°22’N, 110°20’ W), 26 fathoms, December 1968, 7 specimens, dredged by Captain Antonio Luna of Guaymas, received by Roy Poorman. Type Material: Holotype, LACM 1496, 1 paratype, LACM 1497, single paratypes, CAS, ANSP, USNM, 2 paratypes, Poorman collection. cos Referred Material: AHF, 3 stations near Angel de la Guarda Island, 54-90 fathoms, 4 specimens; Shasky col- lection, 2 specimens, Guaymas, Sonora, 40-125 fathoms; AHF: Isla Ladrones, Panama (943-39); Gorgona Island, Colombia (854-38); La Plata Island, Ecuador (212-34), 6 specimens total, 40-60 fathoms. Discussion: The available material suggests that distribu- tion is discontinuous; specimens from the Gulf of Cali- fornia are of uniform size similar to that of the holotype, while those from Panama, Colombia, and Ecuador are exact miniatures, measuring about 15 mm in height, 5 mm in diameter, but otherwise matching in every respect. Of the Panamic Clathrodrillias this has the least tabulate outline and the most numerous spiral cording. The spe- cies is dedicated to Dr. S. Stillman Berry of Redlands, California, whose contributions to the systematics of Pan- amic mollusks are extensive. 20. Cerodrillia asymmetrica McLean & Poorman, spec. nov. (Figure 20) Description of Holotype: Shell small for the genus, dull surfaced, uniformly brownish white; length of aperture greater than 14 the length of the shell; subsutural area evenly sloping, periphery angulate. Protoconch of 314 relatively large whorls, postnuclear whorls 5. Axial ribs 9 on early whorls, increasing to 1] and terminating in a massive axial swelling that strengthens the lip ¥% turn back, ribs weak in the subsutural area, angulate at the periphery, and fading at the pillar; spiral sculpture of about 7 threads on the pillar. Sinus moderately deep, U- shaped, bordered on the inside by curved parietal callus, with an angular slot behind the callus pad directed toward THE VELIGER Vol. 14; No. 1 the suture; lip edge thin, anterior end of aperture only faintly notched; columella descending vertically, columel- lar callus not raised. Height, 6.1, diameter, 2.7 mm. Type Locality: Tagus Cove, Albemarle (Isabela) Island, Galapagos Islands, Ecuador (0°16’08” S, 91°22’38” W), 10-18 fathoms, 15 January 1934, 6 specimens, dredged by the R/V Velero, AHF station 157-34. Type Material: Holotype, LACM-AHF 1498, 2 para- types, LACM-AHF 1499, single paratypes, CAS, ANSP, and USNM. Referred Material: AHF, 4 additional lots from Albe- marle Island, 50-100 fathoms. Discussion: Cerodrillia asymetrica has the same sized protoconch as the mainland species, C. cybele (Pilsbry & Lowe, 1932), which reaches twice the size, has fewer axial ribs and is more darkly colored. The straight columella and flaring terminal rib impart an asymmetrical outline to the shell, hence the name, derived from Greek. 21. Splendrillia academica McLean & Poorman, spec. nov. (Figure 2/) Description of Holotype: Shell of medium size for the genus; surface dull, banded with blue gray; lip margin, subsutural cord, and peripheral nodes whitish, a darker band of brown connects the peripheral nodes; shoulder concave below a narrow subsutural swelling, aperture more than 1% the length of the shell. Protoconch of 2 smooth whorls with central tip, postnuclear whorls 8. Axial sculpture of 8 elongate ribs on early whorls, in- creasing to 10 on the final whorl, indicated as blunt swellings upon the swollen subsutural collar, nodulous at the periphery but obsolete upon the shoulder sulcus and across the base; spiral sculpture of about 8 grooves upon the pillar. Sinus deep, U-shaped, bounded by a massive pad of curved parietal callus with a sutural slot behind; lip edge not greatly thickened, evenly curved, stromboid notch extremely shallow; anterior end shallowly notched, columella twisted slightly to the left, inner lip raised above the pillar. Height, 13.7, diameter, 5.3 mm (maxi- mum height, 20 mm). Type Locality: Academy Bay, Isla Santa Cruz, Galapagos Islands, Ecuador (0°45’ S, 90°48’ W), 60 meters (33 fath- oms), 15 October 1965, 2 specimens, and November, 1966, 2 specimens, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1500, single paratypes, CAS, ANSP, and USNM. Referred Material: Galapagos Islands: LACM, 8 speci- Vol. 14; No. 1 mens, northern coast, Isla Santa Cruz; AHF 59-33, Cor- morant Bay, Isla Santa Maria; AMNH 110411, 1 speci- men, Academy Bay, Isla Santa Cruz. Discussion: Splendrillia academica is the only eastern Pacific clavine species banded with blue gray. The type species of the genus, the south Australian S. woods: (Bed- dome, 1883) has a narrow subsutural cord rather than a swollen subsutural band, but the features are otherwise characteristic of this genus, which is broadly distributed in the Indo-Pacific. Generic allocation may be an aca- demic question, but the type locality is exact, hence the name. 22. Splendrillia arga McLean & Poorman, spec. nov. (Figure 22) Description of Holotype: Shell small for the genus, sur- face glistening white, translucent; whorls rounded below a slight subsutural concavity, aperture greater than 1 the length of the shell. Protoconch of 2 smooth whorls, tip immersed and lateral; postnuclear whorls 6. Axial sculp- ture of 9 low, rounded ribs on early whorls, becoming completely obsolete on the final whorl, last 14 turn behind the lip evenly swollen, reinforcing the lip; spiral sculpture wanting. Sinus deep, U-shaped, bordered by a pad of curved parietal callus with a sutural slot behind; lip edge not greatly thickened, stromboid notch not apparent; an- terior end shallowly notched, base of columella twisted slightly to the left, inner lip but slightly raised above the pillar. Height, 9.3, diameter, 3.2 mm. Type Locality: Puerto Guatulco, Oaxaca, Mexico (15° 44’28” N, 96°07’51”W), 7 fathoms, 5 December 1937, 5 specimens (2 immature), collected by William Beebe and Templeton Crocker, CAS locality 17832. Type Material: Holotype, CAS 13677, 2 paratypes, CAS 13678, 13679, 1 paratype, LACM 1501, 1 paratype, USNM. Discussion: Splendrillia arga could only be confused with S. lalage (Dall, 1919), a species differing in having axial ribbing on mature whorls, a hump on the back of the last whorl, and a banding pattern. Splendrillia arga lacks a subsutural thread, but could otherwise be regarded as meeting all the criteria for Splendrillia. The name is a Greek adjective meaning shining or glistening. 23. Splendrillia bratcherae McLean & Poorman, spec. nov. (Figure 23) Description of Holotype: Shell small for the genus, sur- face glossy; pale flesh colored with lighter peripheral THE VELIGER Cy Page 99 nodes and a yellow-brown band in the subsutural area and another narrow band below the peripheral nodes; shoulder concave below a weak subsutural swelling; aper- ture ¥4 the length of the shell. Protoconch of 2 bulbous whorls, the tip small and slightly off center; postnuclear whorls 8. Axial sculpture of 10 low set nodes on early whorls, increasing to 12 on the penultimate whorl, in- dicated as faint swellings in the immediate subsutural area and as elongate nodes at the periphery, obsolete across the base and pillar; back of last whorl with a mas- sive axial swelling 14 turn back; spiral sculpture lacking. Sinus deep, U-shaped, bordered by a massive pad of curved parietal callus with a sutural slot behind; lip edge not greatly thickened, stromboid notch shallow, anterior end of aperture moderately notched, inner lip callus not strongly raised. Height, 12.3, diameter, 4.1 mm. Type Locality: South of Tiburon Island, Gulf of Cali- fornia, Mexico (28°43’45” N, 112°17’50” W), 20 fathoms, 1] March 1936, 5 specimens, dredged by the R/V Velero, AHF station 566-36. Type Material: Holotype, LACM-AHF 1502, 2 para- types, LACM-AHF 1503, 1 paratype CAS; 1 paratype, USNM. Referred Material: Poorman and Shasky collections, dredged in the vicinity of Guaymas; USNM 555706 and LACM 66-30, dredged off La Paz, Baja California. Discussion: Splendrillia bratcherae differs from S. lalage (Dall, 1919) in being larger, having more whorls, a greater number of less elongate peripheral nodes, and a fainter color pattern. Although the general outline resembles that of the type species of Splendrillia, the stout axial swelling of the back of the last whorl of S. bratcherae and S. lalage is not found in S. woods: (Beddome, 1883). The species is dedicated to Twila Bratcher (Mrs. Ford Bratcher) of Los Angeles, in recognition of her work with the Tere- bridae. 24. Fusiturricula andrei McLean & Poorman, spec. nov. (Figure 24) Description of Holotype: Shell of average size for the genus; pinkish brown with darker areas between the axial ribs, columella white; aperture plus canal more than %4 the length of the shell; suture impressed, shoulder con- cave and smooth except for a narrow subsutural thread, whorl outline tabulate; anterior canal straight, as long as the aperture. Protoconch (of paratype) of 2 bulbous whorls with small central tip, adult axial sculpture emerg- ing after a nodulous, carinate stage; postnuclear whorls 10. Axial ribs 10 on early whorls, increasing to 17 on final whorl, arising at the shoulder and fading upon the body Page 100 THE VELIGER Vol. 14; No. 1 whorl; final whorl with irregularly spaced swollen axial ribs; spiral sculpture of 2 strong cords on early post- nuclear whorls, beaded on crossing the axial ribs, major spiral cords increasing to 4 on the penultimate whorl, with additional minor ribs across the base, ribbing on the back of the anterior canal fine and even. Parietal callus lacking, sinus at the suture, lip thin edged (broken back and partially repaired in holotype). Height, 32.2, diam- eter, 10.0 mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’S, 90°21’ W), 100-200 meters (55-110 fathoms), 23-29 July 1969, 6 specimens (5 immature), dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1504, 4 paratypes, Referred Material: AHF 788-38, 1 immature specimen, 55 fathoms, Daphne Major Island, Galapagos. Discussion: Fusiturricula andrei differs from the main- land species F. armilda (Dall, 1908) in having more nu- merous axial ribs and spiral cords, a straighter canal, and a more tabulate shoulder. We are pleased to name the species for André DeRoy. 25. Crassispira (Dallspira) martiae McLean & Poorman, spec. nov. (Figure 25) Description of Holotype: Shell small for the subgenus, uniformly grayish black, aperture blue-gray within, sur- face texture waxen; subsutural area concave; suture marked by a narrow, undulating cord with another, slightly more prominent cord below. Protoconch of 2 smooth whorls, postnuclear whorls 9. Axial ribs 13 on early and final whorls, flexed to the right at the shoulder and extending across the base; back of last whorl with a stronger axial rib 4% turn back from the lip; spiral sculp- ture of 3 additional grooves in the concave subsutural area and regularly spaced grooves on the upper half of the body whorl, changing to broad, straplike cording on the lower half, producing lighter colored beads on cross- ing the narrow axial ribs on the lower half; pillar with narrow, raised cords. Sinus deep, U-shaped, bordered on the inside by curved parietal callus showing incremental layering; lip edge moderately thick, stromboid notch faint; anterior end truncate, weakly notched, inner lip raised above the pillar. Height, 11.0, diameter, 4.7 mm. Type Locality: Venado Island, Panama Canal Zone (8° 53’ N, 79°36’ W), at low tide among rocks, 19 specimens collected by James H. McLean and Donald Shasky, 8-11 March 1970, LACM station 70-15. Type Material: Holotype, LACM 1506, 7 paratypes, LACM 1507. Single paratypes, AMNH, ANSP, CAS, SDNHM, USNM, 6 paratypes, Shasky Collection. Discussion: Although of the same general form as Cras- sispira coelata (Hinds, 1843), with which it occurs, C. martiae differs in being broader with a more tabulate out- line and having a less pronounced subsutural cord. Axial sculpture is stronger in these two species than in other Dallspiras, but the sinus is characteristic of that group. We are pleased to name the species for Ann Marti (Mrs. Ted Marti) of Balboa, Canal Zone, who was most helpful during our visit to Panama. 26. Crassispira (Striospira) coracina McLean & Poorman, spec. nov. (Figure 26) Description of Holotype: Shell of medium to small size for the subgenus; uniformly black, aperture bluish gray within, surface texture waxen; sutures weakly impressed, subsutural area swollen, subsutural cord a prominent keel. Protoconch of 2 smooth, glossy brown whorls; post- nuclear whorls 9. First postnuclear whorl with 9 slanting axial folds, second postnuclear whorl with about 18 nearly vertical ribs crossed by 3 narrow cords; the first 4 post- nuclear whorls impart a concave outline to the spire; axial ribs on final whorl 18, arising below the subsutural cord and curving across the base; spiral sculpture of fine striae, increasing in strength toward the pillar. The suture rises on the last 4 turn, the lip massively swollen back of the edge. Sinus U-shaped, shallow and narrow, directed later- ally across the thickened lip; stromboid notch slight; an- terior canal broad and shallow, twisted to the right, inner lip callus layered. Height, 15.3, diameter, 6.6 mm. Type Locality: Venado Island, Panama Canal Zone (8°52’ N, 79°36’ W), at low tide among rocks, 8 specimens (4 immature) collected by James H. McLean and Donald Shasky, 8-11 March 1970, LACM station 70-15. Type Material: Holotype, LACM 1508, 2 paratypes, LACM 1509, single paratypes, ANSP, CAS, USNM, 2 paratypes, Shasky Collection. Referred Material: AHF 253-34, Puerto Culebra, Costa Rica, 1 specimen; LACM 68-41, Cuastecomate, Jalisco, 1 specimen; LACM 71-23, Point Arena, Baja California, 4 specimens: Shasky Collection, El Pulmo, Baja Califor- nia, 2 specimens. Vol. 14; No. 1 Discussion: Crassispira coracina has a narrow, laterally directed sinus unlike that of any other species known to us. The other Striospiras have a parietal tubercle and a more upward directed sinus, but C. coracina is tenta- tively placed here because the sinus is shallow and the suture rises on the last whorl. No radula was found in 2 of the paratype specimens. Mexican specimens average several mm smaller than those from Panama and Costa Rica and have less pronounced axial ribbing. The name coracina means black as a raven, an appropriate desig- nation for these shells. 27. Crasstspira (Monilispira) currani McLean & Poorman, spec. nov. (Figure 27) Description of Holotype: Shell small for the subgenus; ground color gray, subsutural band and basal cords dark orange; aperture 1% the length of the shell; shoulder con- cave below a broad, inflated subsutural band. Protoconch glossy black, whorls 2; postnuclear whorls 8. Axial sculp- ture of 22 low ribs crossed by spiral cords of nearly equal strength and spacing, producing squarish orange beads at intersections, one such row of encircling beads on early whorls, 4 on the penultimate and 12 altogether on the final whorl, more closely spaced upon the pillar; entire surface finely striate throughout. Sinus broad and shal- low, bordered on the inside by curved and layered parie- tal callus; lip slightly thickened behind the edge; strom- boid notch shallow; anterior canal broad and shallow, slightly twisted to the left; inner lip callus raised only on the pillar. Height, 11.1, diameter, 4.3 mm. Type Locality: Sayulita, Nayarit, Mexico (20°52’N, 105°28’ W), at low tide among rocks, 12 specimens (7 im- mature), collected by Norman P. Currin and Gale Sphon, 9-23 January 1970, LACM station 70-4. Type Material: Holotype, LACM 1510, 1 paratype, LACM 1511, single paratypes, CAS, ANSP, USNM, 7 paratypes, Currin Collection. ims Referred Material: LACM 65-15, Los Arcos, Banderas Bay, Jalisco, 3 specimens. Discussion: Crassispira currani differs from C. trimariana Pilsbry & Lowe, 1932, in having a more concave shoulder, more numerous spiral cording and dark orange rather than dingy yellow tubercles. A red filter was used to bring out the dark orange banding in the photograph. We name the species for Norman P. Currin, of San Diego, who collected most of the specimens. THE VELIGER Page 101 28. Lioglyphostoma rectilabrum McLean & Poorman, spec. nov. (Figure 28) Description of Holotype: Shell moderately large for the genus; uniformly yellowish white, dull surfaced; length of aperture slightly less than 1% the length of the shell; suture impressed, early whorls rounded, later whorls with a concave subsutural area. Protoconch of 3 smooth whorls (tip missing), developing a low carination on the third whorl; postnuclear whorls 7. Axial sculpture of 9 ribs on early whorls, increasing to 14 on final whorl, strongly de- veloped and extending from suture to suture on early whorls, arising below the subsutural channel on final whorl, and extending weakly across the base and pillar; spiral sculpture on early whorls of 3 major cords, increas- ing to 6 on the penultimate, total 18 across the final whorl and pillar, with numerous intervening spiral striae, cords and striae overriding the axial ribs. Sinus U-shaped, deeply penetrating the massive varix that strengthens the lip behind its edge, bordered on the inside by parietal callus and a layered extension of the lip, nearly sealing the sinus entrance; lip edge nearly straight, stromboid notch shallow; anterior canal elongate, inner lip not raised. Operculum with terminal nucleus, radula of duplex crassispirine type. Height, 16.2 mm; diameter, 6.1 mm. Type Locality: Off Cabo Haro, Guaymas, Sonora, Mex- ico (27°50’ N, 110°55’ W), 40-125 fathoms, 2 September 1960, 1 specimen dredged, Ariel Expedition, Donald Shasky Collection. Paratype from same locality, 15-25 fathoms, 28 August 1960, Helen DuShane Collection. Type Material: Holotype, LACM 1512, paratype, Du- Shane Collection. The paratype is slightly immature, not showing the constriction of the sinus entrance. Discussion: Lioglyphostoma rectilabrum is easily sepa- rable from the widely distributed L. ericea (Hinds, 1843) in having spiral striae, a more massive appearance, and lacking a subsutural cord, which may be weakly indi- cated in L. ericea. The name is a compound Latin noun, meaning straight lip, suggested by the massive, uncurved lip. 29. Maesiella maesae McLean & Poorman, spec. nov. (Figure 29) Description of Holotype: Shell small for the genus, tan, with lighter aperture; whorls weakly rounded, subsutural area slightly concave, bearing a narrow, raised subsutural Page 102 thread; the suture descends rapidly, exposing much of the penultimate whorl. Protoconch of 3 whorls, first 2 whorls smooth (tip missing), slightly bulging at the periphery; 6 strong diagonal ribs arise on the last 4% of the third nuclear whorl and cease abruptly, replaced by 5 spiral cords and only faint axial ribs; postnuclear whorls 6. Axial sculpture on penultimate whorl of 16 weak ribs, nearly obsolete on final whorl, crossed by evenly spaced major spiral cords starting at the periphery and becoming stronger and more closely spaced on the pillar; entire shell with fine spiral striae throughout. Sinus deep, U-shaped, the entrance nearly sealed by downward growth of the lip on the inside; lip strengthened by a massive terminal varix, the spiral cording continuous to the narrow lip edge, stromboid notch shallow; anterior canal short, with a shallow notch, inner lip not raised above the pillar. Height, 9.2, diameter, 3.3 mm. Operculum with terminal nucleus. Type Locality: First cove north of Saladita Cove, near Guaymas, Sonora, Mexico (27°53’15” N, 110°58’ W), 30— 60 feet, May 29-June 1, 1968, 4 specimens taken by div- ing by James H. McLean, LACM loc. 68-27. Type Material: Holotype, LACM 1513, 3 paratypes, LACM 1514. Fourteen additional paratypes dredged by Forrest and Roy Poorman in 17 fathoms, | mile south of Puerto San Carlos, Guaymas, March 1964 and December 1965. Single paratypes, AMNH, ANSP, CAS, MCZ, SDNHM, SU, and USNM, 7 paratypes, Poorman Col- lection. Referred Material: LACM, | specimen dredged by Roy Poorman at Puertecitos, Baja California. Discussion: Maesiella maesae is of the same size as M. hermanita (Pilsbry & Lowe, 1932), but is lighter colored with more numerous, but weaker spiral cording and axial THE VELIGER Vol. 14; No. 1 ribbing. This is the type species of Maesiella McLean, 1971, both genus and species dedicated to Virginia Orr Maes, of the Philadelphia Academy of Natural Sciences. 30. Carinodrillia lachrymosa McLean & Poorman, spec. nov. (Figure 30) Description of Holotype: Shell small for the genus, aper- ture 43 the length of the shell; surface texture waxen, ground color yellow brown, axial ribs white, subsutural area with flecking of white, base more darkly colored; whorls rounded below a moderately concave subsutural area. Protoconch of 2% smooth, dark colored whorls, fol- lowed by % whorl with 7 closely spaced axial ribs, chang- ing to the mature rib count of 7 per whorl; postnuclear whorls 8. Axial ribs strong, extending from suture to suture, but subdued across the subsutural area on the final whorl and fading across the base; spiral sculpture of microscopic striae throughout, more strongly marked across the pillar; a pair of strong spiral cords emerge on the back of the last whorl, slightly beaded on crossing the last 3 axial ribs. Lip preceded by an exceptionally strong axial rib 14 turn back, followed by an axial rib of normal thickness. Sinus deep, U-shaped, bordered on the inside by layered parietal callus (not fully developed in holotype); lip edge thin, strengthened away from the edge by a weak rib, stromboid notch shallow; anterior canal broad, weakly notched, directed slightly to the right; columella nearly straight, inner lip defined but not raised. Height, 12.6, diameter, 4.3 mm (largest specimen, 16.9 mm in height). Operculum leaf shaped. Type Locality: Cuastecomate Bay (NW of Barra de Na- vidad), Jalisco, Mexico (19°13’45” N, 104°44’53” W), 15— Plate Explanation Note: All photographs are of the holotypes of the various new species; the authors in all cases are McLean & Poorman. Figure 28: Lioglyphostoma rectilabrum X 2.8 Figure 29: Maesiella maesae XK 4.3 Figure 30: Carinodrillia lachrymosa X 3.5 Figure 31: Compsodrillia gracilis x 3.4 Figure 32: Compsodrillia olssoni X 2.6 Figure 33: Compsodrillia opaca Xx 2.1 Figure 34: Compsodrillia undatichorda X 2.8 Figure 35: Borsonella abrupta Xx 2.1 Figure 36: Borsonella galapagana X 2.8 Figure 37: Cymakra baileyi X 8.7 Figure 38: Cymakra granata X 6.9 Figure 39: Clathurella maryae X 6.0 Figure 40: Glyphostoma (Glyphostoma) pustulosa x 1.9 Figure 41: Glyphostoma (Glyphostoma) scobina X 3.4 Figure 42: Euclathurella acclivicallis . x 3.7 Figure 43: Acmaturris ampla x 4.4 Figure 44: Thelecythara dushanae x 5.1 Figure 45: Kurtzia elenensis X 9.3 Figure 46: Kurtzia humboldti x79 Figure 47: Pyrgocythara angulosa x 8.1 Figure 48: Daphnella gemmulifera X 3.3 Figure 49: Daphnella retusa X 3.5 Figure 50: Rimosodaphnella deroyae a By Figure 51: Philbertia shaskyi x 7.2 Figure 52: Kermia informa X 6.6 Figure 53: Veprecula tornipila X 9.5 Tue VELIcER, Vol. 14, No. 1 [McLEAN &« Poorman] Figures 28 to 53 S Figure 29 Figure 30 Figure 31 Figure 32 F igure 34 Sraam Figure 48 Figure 49 Figure 50 Figure 51 Figure 52 Figure 53 Vol. 14; No. 1 65 feet, 13-21 October 1968, 2 specimens taken by diving by James H. McLean, LACM loc. 68-41. Type Material: Holotype, LACM 1515, paratype, LACM 1516. Referred Material: Poorman collection, Guaymas; Shasky collection, Espiritu Santo Island, and El Pulmo, Baja California; LACM, Cerralvo Island, El Pulmo, and Cape San Lucas; USNM 128227, San Jose Island, Gulf of Cali- fornia, all specimens taken by shallow diving. Discussion: Carinodrillia lachrymosa is smaller than C. dichroa (Pilsbry & Lowe, 1932) and lacks the spiral cord- ing of that species. It is more slender and with a different color pattern than that of C. alboangulata (E. A. Smith, 1882). The name is Latin, full of tears, suggested by the white axial ribs on the dark ground, resembling teardrops. 31. Compsodrillia gracilis McLean & Poorman, spec. nov. (Figure 31) Description of Holotype: Shell small for the genus, fusi- form, with a moderately elongate anterior canal; aperture less than 14 the length of the shell; whorls rounded, suture impressed; color tan under a thin brown periostracum. Protoconch of 3 glossy, white whorls with deeply im- pressed sutures, tip small, change to mature sculpture gradual; postnuclear whorls 8. Axial sculpture of 8 nar- row ribs on early whorls, increasing to 12 on final whorl, strong at the periphery, but obsolete on the pillar; spiral sculpture of a strong undulating subsutural cord close to the suture, a smooth concave channel below; 2 major peripheral cords per whorl with 2 minor cords above and below, producing strong, projecting beads on crossing the axial ribs, all spiral cords present from the earliest adult whorls; cords of the base and pillar 14, becoming less prominent upon the pillar; fine growth lines present throughout. Sinus deep, U-shaped, the opening laterally directed, bordered on the inside by triangular callus layered downward; lip edge thin, preceded by a more prominent axial rib 4% turn back; stromboid notch shal- low, anterior canal elongate, weakly notched, inner lip callus slightly raised above the pillar. Height, 12.9, diam- eter, 4.2 mm. Largest paratype, 16.9 mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’ S, 90°21’ W), 100-200 meters (55-110 fathoms), 23-29 July and 5 December 1969, 8 specimens, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1517, 4 paratypes, LACM 1518, single paratypes, ANSP, CAS, and USNM. THE VELIGER Page 103 Referred Material: Galapagos Islands: AHF 190-34, 1 specimen, 55 fathoms, S end Isabela Island; AHF 788-38, 1 specimen, 55 fathoms, Daphne Major Island; AHF 792- 38, 1 specimen, 70-80 fathoms, Daphne Minor Island. Discussion: Smallest of the Compsodrillia, this resembles only C. opaca, new species, differing chiefly in having a longer canal and more numerous spiral cords upon the pillar. The name is Latin, slender or graceful. 32. Compsodrillia olssoni McLean & Poorman, spec. nov. (Figure 32) Description of Holotype: Shell of small to moderate size for the genus, high spired, but with short, truncate an- terior end; periostracum in thin ridges, easily worn off; surface texture shiny, color light tan, spiral cording and pillar lighter colored. Protoconch of 3 light brown whorls (tip missing in holotype), developing a low peripheral carination on the second whorl, thin axials on the third whorl, mature sculpture appearing on the fourth, or first postnuclear whorl; postnuclear whorls 9. Axial sculpture of 7 stout ribs on early and later whorls, strong at the periphery, but obsolete across the subsutural channel and pillar; spiral sculpture of a strong undulating subsutural cord and a major peripheral cord with two cords of lesser strength above and below, the lowermost adjacent to the scarcely impressed suture; additional basal cords 10, entire shell with microscopic spiral lirae and growth lines. Sinus deep, U-shaped, entrance nearly sealed by triangular callus layered downward, strength at the top by the termi- nation of the subsutural cord; lip edge thin, strengthened by an axial rib and a more massive rib % turn back, strom- boid notch shallow; anterior canal short and broad, shal- lowly notched, inner lip callus slightly raised. Height, 17.0, diameter, 6.4 mm. Operculum with terminal nu- cleus. Type Locality: Santa Elena Bay, Ecuador (2°08’20” S, 81°00’15” W), 8-10 fathoms, 9 February 1934, 13 speci- mens (3 immature), dredged by the R/V Velero, AHF station 209-34. Type Material: Holotype, LACM-AHF 1519, 8 para- types, LACM-AHF 1520, single paratypes, AMNH, ANSP, CAS, and USNM. Referred Material: Poorman Collection, 2 specimens, 17 fathoms, Guaymas, Mexico; LACM 38-9, 1 specimen, 40- 70 fathoms, Guatulco Bay, Oaxaca, Mexico. Discussion: Compsodrillia olssoni most resembles C. jacu- lum (Pilsbry & Lowe, 1932), but is larger, less slender, lighter colored, and has few spiral cords upon the pillar. Page 104 THE VELIGER Vol. 14; No. 1 We dedicate this species to Axel A. Olsson, of Coral Gables, Florida, author of numerous contributions on New World mollusks, living and fossil. 33. Compsodrillia opaca McLean & Poorman, spec. nov. (Figure 33) Description of Holotype: Sheil of moderate size for the genus, anterior canal short, aperture ¥3 the length of the shell, whorls rounded, suture impressed; color brown with a broad, yellowish white peripheral band under a thin brown periostracum. Protoconch missing (all speci- mens); remaining whorls 9. Axial sculpture of 9 narrow ribs on early whorls, increasing to 13 on final whorl, weak in the subsutural area and obsolete on the pillar; spiral sculpture of a strong, undulating subsutural cord adjacent to the suture, a smooth subsutural channel below; early whorls with 2 strong narrow spiral cords, a third fully emerged on the penultimate whorl, strongly beaded on crossing the narrow axial ribs; base with 9 additional spiral cords; growth striae microscopically fine. Sinus deep, U-shaped, the opening laterally directed and closely con- stricted by triangular callus representing the termination of the subsutural cord; lip with a weak rib back of the edge and a slightly stronger rib than normal just behind; stromboid notch shallow, anterior canal broad, weakly notched, inner lip not raised. Height, 20.6 mm; diameter, 6.8 mm. Operculum with terminal nucleus. Type Locality: Ranger Bank off Cedros Island. Baja Cali- fornia (28°31’01” N, 115°30’31” W), 76-77 fathoms on loose rock, 25 February 1941, 2 specimens, dredged by the R/V Velero, AHF station 1247-41. Type Material: Holotype, LACM-AHF 1521, 1 paratype, LACM-AHF 1522. Referred Material: AHF, 5 stations, Cedros Island vicin- ity, 49-81 fathoms, 14 specimens total; CAS 27598, Cedros Island, 3 specimens; AHF 618-37, 75 fathoms, 2 speci- mens, San Jaime Bank, near Cape San Lucas, Baja Cali- fornia; AHF 1058-40, 68-54 fathoms, | specimen, Angel de la Guarda Island, Gulf of California. Discussion: Compsodrillia opaca is larger than C. gracilis new species, and has a shorter canal and fewer spiral cords on the pillar. The periostracum tends to obscure the color pattern, thereby suggesting the name, an adjec- tive meaning shaded. 34. Compsodrillia undatichorda McLean & Poorman, spec. nov. (Figure 34) Description of Holotype: Shell of moderate size for the genus, anterior canal moderately long, aperture 1% the length of the shell, subsutural area markedly concave, whorls tabulate; color tan under a thin brown periostra- cum. Protoconch of 3 whorls, first 2 smooth, third with narrow, vertical axial ribs and a peripheral bulge, chang- ing gradually to mature sculpture; postnuclear whorls 8. Early whorls with 8 stout axial ribs, increasing to 9 on final whorl; ribs arising in the subsutural channel, strong across the body whorl and obsolete upon the pillar; spiral sculpture of a sharply projecting subsutural cord adjacent to the suture; below the smooth subsutural channel 3 sharply projecting cords on early whorls, on successive whorls 1 additional cord arising above and 2 below to make 6 such cords on the back of the penultimate whorl; body whorl and base in advance of the aperture with a total of 18 sharp cords; cords more strongly projecting on crossing the axial ribs. Sinus deep, U-shaped, the opening laterally directed, bordered on the inside by triangular callus layered downward, strengthened above by the ter- mination of the subsutural cord; lip edge thin with a weak rib behind and a more prominent axial rib ¥% turn back; stromboid notch shallow, anterior canal moderately elon- gate, weakly notched; inner lip callus slightly raised above the pillar. Height, 16.2, diameter, 6.2 mm (maximum length 22 mm). Type Locality: South of Isla Albany, Galapagos Islands, Ecuador (0°10’45”S, 90°52’08” W), 50-70 fathoms, 24 January 1934, 1 specimen, dredged by the R/V Velero, AHF station 183-34. Type Material: LACM-AHF 1523. Referred Material: Galapagos Islands (none mature): AHF 324-35, 1 specimen, 45 fathoms, Tagus Cove, Isabela Island; LACM, 44—82 fathoms, northern and southern coasts of Isla Santa Cruz, 3 specimens. Discussion: None of the other Compsodrillias have sharp projecting spiral cording and this species thereby stands well apart. The name is a Latin noun derived from undatus—wavy, and chorda—rope or twine, suggested by the characteristic spiral cording. 35. Borsonella abrupta McLean & Poorman, spec. nov. (Figure 35) Description of Holotype: Shell moderately large for the genus, fusiform, with elongate canal; surface texture Vol. 14; No. 1 waxen under a thin, flaking, dark brown periostracum; color yellowish brown under the periostracum, the pe- riphery lightest in color, the subsutural area and base slightly darker, the pillar darkest; aperture plus canal 14 the length of the shell; suture undulating, immediate sub- sutural area inflated. Protoconch missing, first 2 whorls with sculpture eroded away, sculptured whorls 7. Axial ribs 9 on early whorls, 10 on final whorl; ribs massive, arising below the subsutural channel and descending ver- tically, obsolete upon the base and pillar. Spiral striae irregular in strength and spacing, fine growth lines pres- ent throughout, the V-shaped markings of the anal fasciole prominent. Outer lip broken in the type; inflated and de- pressed areas within the aperture, corresponding to axial ribbing; anterior canal moderately long, weakly notched; columella sunken, a single prominent plication emerging deep within. Height, 21.6, diameter, 7.4 mm. Type Locality: Northwest of Charles (Santa Maria) Is- land, Galapagos Islands, Ecuador (1°09’ N, 90°35’ W), 250 fathoms, 23 January 1938, 1 specimen, dredged by the R/V Velero, AHF station 802-38. Type Material: Holotype, LACM-AHF 1524. Discussion: No other eastern Pacific species of Borsonella has massive, vertical axial ribbing. The name is a Latin adjective meaning steep or broken, suggested by the abruptly terminating axial ribbing. 36. Borsonella galapagana McLean & Poorman, spec. nov. (Figure 36) Description of Holotype: Shell of moderate size for the genus, fusiform, the aperture extending nearly %4 the length of the shell, whorls angulate, upper half of whorl slightly concave, lower half sloping inward; color light tan under a thin olive periostracum. Protoconch of 2 bulbous whorls with lateral tip, change to mature sculpture grad- ual, through a stage with a peripheral bulge, then a carina- tion; postnuclear whorls 7. Early whorls with 13 periph- eral nodes, persisting for 4 whorls, but becoming obso- lete on final whorls; spiral sculpture on early whorls of 3 cords on the lower half of the whorl, becoming obsolete by the final whorl; final whorl in advance of the aperture with weak and irregular cords between the periphery and the siphonal fasciole. Columellar area broad, 2 strong plicae arising deep within, the uppermost the strongest; sinus broad and deep, U-shaped, occupying most of the shoulder sulcus; lip not greatly thickened, arcuate, strom- boid notch absent; anterior canal broad, unnotched, columella sloping to the left. Height, 15.8, diameter, 6.1 mm. Operculum vestigial, with apical nucleus. THE VELIGER Page 105 Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’ S, 90°21’ W), 170-200 meters (93-110 fathoms), 26-27 July 1969, 5 specimens, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1525, 3 paratypes, LACM 1526, | paratype, ANSP. Discussion: No other eastern Pacific Borsonella having 2 columellar plicae is known, but the profile of B. gala- pagana is characteristic of that genus. Generic allocation is provisional. 37. Cymakra baileyi McLean & Poorman, spec. nov. (Figure 37) Description of Holotype: Shell small for the genus, tan with a slightly darker band below the periphery, with oc- casional darker flecking on the cording of the upper part of the whorl; whorls rounded, suture impressed; length of aperture nearly % the length of the shell. Protoconch of 1% smooth, bulbous whorls, tip small and lateral; post- nuclear whorls 5. Axial ribs strong, rounded, 10 on early and later whorls, tending to be continuous from whorl to whorl and extending from suture to suture, fading on the base and obsolete upon the pillar, obsolete on the back of the last whorl]; spiral cords 4 per whorl, the upper- most undulating and close to the suture, the lower 2 the most prominent, cords overriding the axial ribs; base and pillar with 11 additional cords. Columella with 2 strong plicae, the uppermost the strongest; lip not thickened (lip edge broken back on holotype), strongly lirate within; anterior canal not differentiated from aperture, un- notched. Height, 4.7, diameter, 2.1 mm. Type Locality: Off Cape San Lucas, Baja California, Mexico (22°56’36” N, 109°47’ W), 33 fathoms, 18 Febru- ary 1936, 1 specimen, grab sample by the R/V Velero, AHF bottom sample station 239. Type Material: Holotype, LACM-AHF 1527. Referred Material: LACM 67-76, 1 specimen, 80-115 feet, Cape San Lucas; AHF 668-37, 1 specimen, 20 fath- oms, Puerto Escondido, Baja California; AHF bottom sample station 290, 1 specimen, 25 fathoms, San Marcos Island, Gulf of California; Bailey collection, 1 specimen, dredged, Bahia de Los Angeles, Baja California. Discussion: Cymakra baileyi has stronger axial ribbing than other eastern Pacific members of the genus. It is closest to C. intermedia (Arnold, 1903), a species described as a Pleistocene fossil but now known to be living off southern California, a much larger species with more Page 106 numerous and weaker axial ribs. We are pleased to name the species for James O. Bailey of Los Angeles. 38. Cymakra granata McLean & Poorman, spec. nov. (Figure 38) Description of Holotype: Shell of average size for the genus, ovate-biconic with nearly flat-sided whorls, aper- ture more than % the length of the shell; color light brown with mottling of white, aperture and pillar white. Protoconch of 2 smooth, bulbous whorls, tip small (bro- ken in holotype); postnuclear whorls 5. Axial ribs on early whorls 14, increasing to 28 on final whorl, ribs nar- tow and weak, obsolete below the periphery, crossed by narrow spiral cords, finely beaded at intersections, 3 on the first 2 postnuclear whorls, 4 on the fourth, 5 on the last whorl above the aperture, 16 additional on the base and pillar; basal cords flat-topped, with narrower inter- spaces. Columella excavated upon the pillar, 2 weak but distinct plicae deep within; sinus and anal fasciole not indicated, lip thick and swollen behind the edge, 10 low denticles just within; aperture long and narrow, anterior canal not differentiated or notched. Height, 6.2, diameter, 2.7 mm. Type Locality: Off SW end Isla Monserrate, Gulf of Cali- fornia (25°34’ N, 111°05’ W), 20-40 fathoms, 1 Septem- ber 1960, 1 specimen, dredged on the Ariel Expedition, Shasky Collection. Type Material. Holotype, LACM 1528. Discussion: Cymakra granata most resembles the Califor- nian C. gracilior (Tryon, 1884), but has a smaller proto- conch, less inflated whorls, a longer aperture, 3 rather than 4 cords on the first and second postnuclear whorls, more numerous cords on the body whorl, and weaker columellar plicae. The name is a Latin adjective, having many grains or seeds, suggested by the sculpture of fine granular beading. 39. Clathurella maryae McLean & Poorman, spec. nov. (Figure 39) Description of Holotype: Shell of average size for the genus, with rounded whorls, deeply impressed sutures, a constricted pillar, and a moderately elongate anterior canal; color yellowish brown with a narrow brown sub- sutural band and dark bands of brown across the base and pillar, the sinus and lower margin of the lip dark brown. Protoconch of 4 whorls including a minute tip, last 2 whorls with a sharp peripheral keel and weak axial lamel- THE VELIGER Vol. 14; No. 1 lae on the lower half; postnuclear whorls 5. Axial ribs 9 on early whorls, increasing to 11 on final whorl, strong, rounded, running from suture to suture, becoming obso- lete upon the base and pillar; spiral sculpture of at first 3, then 4, strong cords on the lower half of the whorl, over- riding the axial ribs and strongly beaded at intersections; shoulder with at first 4, then 5, smaller, narrower, more closely spaced spiral cords; base and pillar with 9 addi- tional cords; interspaces minutely pustulose throughout. Sinus deep, U-shaped, bordered on the inside by a curved pad of parietal callus; lip strengthened behind by a mas- sive axial rib, lip with 5 denticles away from the edge, the uppermost the largest; anterior canal twisted to the left and deeply notched; columella excavated upon the pillar, 3 weak denticles extending within. Height, 7.5, diameter, 2.9mm. Type Locality: One mile S of E promontory at entrance to Bahia San Carlos, Guaymas, Sonora, Mexico (27°56’ N, 111°05’W), 17 fathoms on gravel bottom, December 1963, 7 specimens dredged by Forrest and Roy Poorman. Type Material: Holotype, LACM 1529, single paratypes, CAS, ANSP, and USNM, 3 paratypes, Poorman Col- lection. s Referred Material: AHF 1261-41, 1 specimen, 24 fath- oms, near Cedros Island, Baja California. Gulf of Califor- nia: LACM, | specimen dredged off Puertocitos; AHF 712-37, 1 specimen, 50—75 fathoms off Angel de la Guarda Island; Shasky Collection, 2 specimens, 20-40 fathoms off Monserrate Island; LACM 66-22, 1 specimen, 10-30 fathoms, Muertos Bay, Galapagos Islands: AHF bottom sample station 415, 1 specimen, 55 fathoms, Duncan Island. Discussion: Clathurella maryae differs from C. rava (Hinds, 1843) and C. rigida (Hinds, 1843) in color pat- tern and proportions and in having a moderately long anterior canal rather than a truncate anterior end. The specimen from the Galapagos Islands has one less mature whorl but otherwise agrees with those from the Gulf of California. We are pleased to name the species for Senora Mary Ricaud of Guaymas, Mexico. 40. Glyphostoma (Glyphostoma) pustulosa McLean & Poorman, spec. nov. (Figure 40) Description of Holotype: Shell large for the genus, sculp- tured with weak peripheral nodes below a shallow sub- sutural channel, length of aperture ¥% the length of the shell; color creamy white with diffuse blocks of yellowish Vol. 14; No. 1 brown between the peripheral nodes. Protoconch rela- tively small, 3 whorls, third whorl with a sharp peripheral carination on the lower third; postnuclear whorls 8. Axial sculpture of 9 low peripheral nodes on early and final whorls; spiral sculpture of 3 fine cords on the lower half of early whorls, additional cords gradually taking shape in the subsutural channel and becoming very numerous and regular on the final whorl, about 60 on the final whorl in front of the aperture; entire surface densely packed with microscopic pustules. Sinus deep, U-shaped, not outward projecting, bordered on the inside by a parietal callus pad bearing 4 lirations; lip thin edged, arcuate, with an even thickening behind; lip with 10 denticles away from the edge, the uppermost the strongest; anterior canal broad, deeply notched, flexed to the right; columella with 8 weak denticles. Height, 22.9, diameter, 8.3 mm. Type Locality: Off Jervis Island, Galapagos Islands, Ecuador (0°23’ S, 90°43’ W), 10-20 fathoms, May 1964, 1 specimen dredged by André and Jacqueline DeRoy. Type Material: Holotype AMNH 157263. Referred Material: AHF, single specimens from Tagus Cove, Isabela Island, 10-20 fathoms (66-33, 157-34, 323- 35); LACM, 6 specimens from James Bay, Santiago Island, Galapagos, dredged by the DeRoys at 30 meters, 4 Febru- ary 1969. The holotype is the only fully mature specimen examined. Discussion: We know of no other species of Glyphostoma having sculpture as weak as that of G. pustulosa. The name means full of pustules, suggested by the surface texture, an exaggeration of the pustular surface that is usual in the genus. 41. Glyphostoma (Glyphostoma) scobina McLean & Poorman, spec. nov. (Figure 47) Description of Holotype: Shell small for the genus, sur- face shiny, microscopically pustular or pitted; color whitish with a brown subsutural band, the dark color extending down into the channels between the axial ribs, particularly strong on the back of the last whorl; base broadly banded with brown below the periphery, lip edge brown, pillar and aperture white. Protoconch relatively large, whorls 4, developing by the second whorl a sharp peripheral carination on the lower third; postnuclear whorls 6. Axial sculpture on early whorls 11, increasing to 16 strong, rounded, slanted ribs, arising below the sub- sutural channel, extending across the body whorl and THE VELIGER Page 107 fading on the base; spiral sculpture of low rounded cords, irregular in width and spacing, overriding the axial ribs, 8 on the whorl directly above the anal sinus, 24 additional on the base and pillar. Sinus deep, U-shaped, bordered on the inside by a parietal callus pad having 2 large inner and 2 small outer denticles; lip edge crenulated by ex- tensions of the spiral cords, thickened within and just behind on the outside by a massive rib; lip with 9 denti- cles inside, the uppermost the strongest; anterior canal short, broad and deeply notched; columella slightly sunken below the pillar, bearing 11 denticles decreasing in size anteriorly. Height, 12.9, diameter, 5.2 mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’ S, 90°21’ W), 170-200 meters (93-110 fathoms), 25 July and 5 December 1969, 7 specimens, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1530, 3 paratypes, LACM 1531, single paratypes, CAS, ANSP, and USNM. Referred Material: AHF 199-34, 2 intertidal crab speci- mens, Isla Santa Maria, Galapagos Islands; AHF bottoms sample station 328, 1 immature specimen, 14 fathoms, Chatham Bay, Cocos Island, Costa Rica. Discussion: Glyphostoma scobina is unlike any other east- ern Pacific species in sculpture and color pattern. Its dis- tribution at the Galapagos and Cocos Islands suggests that it may have been more widely distributed in the Panamic Province in the past. The name is a Latin noun meaning file or rasp, suggested by the pustular surface of the spiral cording. 42. Euclathurella acclivicallis McLean & Poorman, spec. nov. (Figure 42) Description of Holotype: Shell of moderate size for the genus; aperture 4 the length of the shell, sutures deeply impressed, whorls sharply tabulate; surface translucent, color creamy white. Protoconch of 2% whorls, tip small, smooth at first, then developing fine axial ribs after 2 whorls and making a smooth transition to mature axial ribbing; postnuclear whorls 612. Axial ribs 11 on early whorls, increasing to 15 on final whorl, extending from suture to suture, undulating the suture, strong and flexed at the shoulder, extending across the body whorl and fad- ing upon the pillar; spiral sculpture on first postnuclear whorl of 4 weak cords, on later whorls of fine, unevenly spaced striae, not deeply incised, dull surfaced rather than shiny, overriding the axial ribs, changing on the pillar to raised cording with narrower, dull surfaced inter- Page 108 spaces. Sinus moderately deep, bordered on the inside by a slight deposition of callus; lip thickened behind the edge by a massive rib, rising above the suture when viewed from the side, stromboid notch shallow; anterior canal broad, not differentiated from the elongate aper- ture, unnotched; inner lip not raised. Height, 11.8, diam- eter, 4.2 mm. Type Locality: Tagus Cove, Isabela Island, Galapagos Islands, Ecuador (0°16’08” S, 91°22’38” W), 75-100 me- ters (41-55 fathoms), 21 January 1968, 1 specimen, dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1532. Referred Material: LACM, 3 specimens (immature or broken), 82 fathoms off southern coast Isla Santa Cruz, dredged by the DeRoys. Discussion: This differs from E. carissima (Pilsbry & Lowe, 1932) in having a less constricted sinus and stronger tabulation of the shoulder. Species allocated to Tenaturris Woodring, 1928, have a concave shoulder and less parietal callus. The type species of Euclathurella Woodring, 1928 (Clathurella vendryesiana Dall, 1896), has a larger nuclear tip, but otherwise the two species fit well in the genus. The name is a Latin noun derived from acclivis—ascending, and callis—narrow foot path, suggested by the strikingly tabulate shoulder. 43. Acmaturris ampla McLean & Poorman, spec. nov. (Figure 43) Description of Holotype: Shell moderately large for the genus; sutures deeply impressed, whorls rounded and somewhat shouldered; color reddish brown, the pillar a darker shade and the shoulder of lighter intensity. Proto- conch of 3 whorls, first 2 smooth with impressed sutures, third bulging or keeled at the periphery and having nar- row axial riblets; postnuclear whorls 6. Axial ribs 11 on early whorls, increasing to 16 on final whorl, ribs narrow, extending from suture to suture, flexed at the shoulder and slanted protractively across the body whorl, termi- nating at one of the strong spiral cords on the pillar; spiral sculpture of 5 major cords per whorl, beaded on crossing the axial ribs, interspaces with fine spiral striae that override the ribs; base with 4 additional major cords, the lowermost strongly beaded at the terminations of the axial ribs; pillar with 2 major and 2 minor spiral cords below, uncrossed by the axial ribs. Sinus broad and shal- low, bounded on the inside by a parietal extension of the lip; lip edge thin, strengthened behind by a varix or massive rib, stromboid notch shallow; anterior canal THE VELIGER Vol. 14; No. 1 broad and unnotched, inner lip not raised. Height, 9.9, diameter, 3.2 mm. Type Locality: Gulf of Guayaquil, Ecuador (3°08’ S, 80° 49’ W), 35 fathoms, 1 specimen, 7 February 1934, AHF bottom sample station 508. The specimen has a hole in the back of the last whorl, a broken columella internally, and a flaking texture, suggesting that it may be subrecent. Type Material: Holotype, LACM-AHF 1533. Discussion: This is the first Recent member of a genus otherwise known from three species from the Caribbean Miocene, differing from all in having more rounded whorls, more deeply impressed sutures and a less con- stricted pillar. The name is a Latin adjective meaning large or great. 44. Thelecythara dushanae McLean & Poorman, spec. nov. (Figure 44) Description of Holotype: Shell moderately large for the genus, suture not deeply impressed, whorls evenly convex, aperture slightly less than % the length of the shell; color uniformly reddish brown. Protoconch whorls 3, evenly convex, shiny, light tan; the axial ribbing of mature whorls emerging weakly at first, followed by spiral sculp- ture; postnuclear whorls 6. Axial sculpture of 14 narrow ribs on early whorls, increasing to about 34 on penulti- mate whorl, becoming nearly obsolete on final whorl, crossed by spiral cords of equal strength on early whorls, far greater strength on later whorls, beaded at intersec- tions and producing squarish cancellations; on the final whorl the cording above the periphery is nearly obsolete, except for the narrow subsutural cord; 16 strong cords upon the base and pillar in advance of the aperture. Sinus deep, U-shaped, bordered on the inside by triangular callus layered downward, lip edge rendered serrate by terminations of the strong spiral cords, thickened behind by a massive varix; stromboid notch shallow but distinct; anterior canal short, differentiated from the rest of the aperture, weakly notched, inner lip callus slightly raised. Height, 8.4, diameter, 2.9 mm. Type Locality: One mile $ of E promontory at entrance to Bahia San Carlos, Guaymas, Sonora, Mexico (27°56’ N, 111°05’ W), 17 fathoms on gravel bottom, April 1962, 6 specimens (3 immature) dredged by Forrest and Roy Poorman. Type Material: Holotype, LACM 1534, single paratypes, ANSP, USNM;; 3 paratypes, Poorman Collection. Vol. 14; No. 1 Referred Material: Poorman Collection: 4 specimens dredged, 2 miles W of Bahia San Carlos; 1 specimen dredged, Candelero Bay, Guaymas; Shasky Collection: 2 specimens, 20 fathoms, Isla Blanca, Guaymas; CAS loc. 27229, 2 specimens, Bahia Honda, Panama. Discussion: Thelecythara dushanae differs from T. flori- dana Fargo, 1953, a species described from the Pliocene of Florida but now known to be represented in the Pana- mic Province, in having more prominent spiral sculpture than axial, and a more defined anterior canal. We are pleased to name the species for Helen DuShane (Mrs. Joseph DuShane), of Whittier, California, in recognition of her work with the Eastern Pacific Epitoniidae. 45. Kurtzia elenensis McLean & Poorman, spec. nov. (Figure 45) Description of Holotype: Shell small for the genus, whorls angulate at the periphery; color uniformly tan, darker in the aperture. Protoconch of 4 whorls, the first 2 smooth, tip small and elevated, third whorl developing faint axial riblets and spiral rows of pustules that grad- ually emerge as beads at intersections of fine cancellate sculpture, peripheral cord becoming more prominent and emerging as the main peripheral keel of the mature sculp- ture; postnuclear whorls 4. Axial ribs 11 on early whorls, increasing to 13 on final whorl, ribs narrow, extending from suture to suture, terminating on reaching the closely spaced spiral cords of the pillar, crossed by a major cord comprising the peripheral keel and two additional major cords below, base and pillar with 14 additional cords, strongly nodular on crossing the narrow axials; secondary cording numerous and with a frosted surface, having fine, elevated, rounded pustules in even rows. Sinus broad and shallow, directed laterally on the shoulder, bordered on the inside by a parietal extension of the lip and with a small tubercle just below the sinus on the lip; lip edge thin but strengthened behind by a large terminal varix; aperture elongate, the anterior canal not differentiated, directed to the left, unnotched; columella slightly sunken below the pillar. Height, 4.4, diameter, 1.9 mm. Type Locality: Gulf of Guayaquil, Ecuador (3°08’ S, 80° 49’ W), 35 fathoms, 2 specimens, 7 February 1934, AHF bottom sample station 508. Type Material: Holotype, LACM-AHF 1535, paratype, LACM-AHF 1536. Discussion: Smallest of the Kurtzias, this is relatively broad and has more numerous axial ribs and major spiral cords than the others. The type locality, the Gulf of Guayaquil, is just to the south of the Santa Elena Penin- sula, hence the name, elenensis. THE VELIGER Page 109 46. Kurtzia humboldti McLean & Poorman, spec. nov. (Figure 46) Description of Holotype: Shell small and relatively slen- der for the genus, whorls angulate at the periphery; color uniformly yellowish tan. Protoconch of 4 whorls, first 2 smooth with a microscopically granular surface, third whorl with 5 rows of pustules that gradually emerge as beads at the intersections of fine axial ribs and spiral cords, the peripheral cord more prominent and becoming the main peripheral keel of the mature sculpture; post- nuclear whorls 4. Axial ribs 11 on early and final whorls, narrow, extending from suture to suture, terminating on reaching the strong spiral cords of the pillar; crossed by a major cord comprising the peripheral keel with another below on early whorls; base and pillar with 11 additional cords, strongly nodular on crossing the narrow axials; secondary spiral cording numerous and with a frosted sur- face, having fine, elevated, rounded pustules in even rows. Sinus relatively deep, with a narrow entrance, directed laterally on the shoulder, bordered on the inside by a parietal extension of the lip, a small tubercle just below the sinus on the lip; lip edge thin but strengthened be- hind by a weak rib and by a slightly larger than normal rib preceding it; aperture elongate, the anterior canal not differentiated, directed slightly to the left, unnotched; columella slightly sunken below the pillar. Height, 5.2, diameter, 2.1 mm. Type Locality: TTagus Cove, Albemarle (Isabela) Island, Galapagos Islands, Ecuador (0°16'08” S, 91°22’38” W), 10-18 fathoms, 15 January 1934, 4 specimens dredged by the R/V Velero, AHF station 157-34. Type Material: Holotype, LACM-AHF 1537, 2 para- types, LACM-AHF 1538, 1 paratype, USNM. Referred Material: Galapagos Islands: AHF 187-34, 2 specimens, 8-10 fathoms, Cartago Bay, Isabela Island; AHF bottom sample 408, 9 specimens, 13 fathoms, Albe- marle Point, Isabela Island. Discussion: Most slender of the Kurtzias, this also has the narrowest and deepest sinus. We name it for Alexander Humboldt, 18th century naturalist. The Humboldt Cur- rent cools the waters of the Galapagos, greatly affecting the fauna of these islands. 47. Pyrgocythara angulosa McLean & Poorman, spec. nov. (Figure 47) Description of Holotype: Shell relatively small for the genus, whorl outline angulate; color yellowish white with brown markings between axial ribs at the periphery, pil- Page 110 lar and aperture white. Protoconch of 2 whorls, tip small and central, first whorl smooth and round, last half of second whorl developing fine axial riblets and a periph- eral carination, gradually changing to mature sculpture; postnuclear whorls 6. Axial ribs strong and broad, 8 on early and final whorls, extending from suture to suture but reaching their crests at the periphery, extending across the base until meeting the strong cording on the pillar; spiral sculpture of a major peripheral cord, a second major cord emerging on the second whorl, cords becoming broad and straplike on the final whorl, inter- spaces with fine spiral striae; base with 3 additional major cords, pillar with 10 strong, closely spaced cords; growth striae throughout, strong upon the shoulder. Sinus shal- low, directed laterally, bordered on the inside with thick- ened parietal callus and a tubercle or denticle just below the sinus on the inside of the lip; lip thickened behind the edge by a terminal varix; anterior canal undifferenti- ated from the aperture, broad, unnotched; columella not raised above the pillar. Height, 5.2, diameter, 2.1 mm. Type Locality: Bahia Guasimas, Sonora, Mexico (27°50’ N, 110°33’ W), intertidal mudflat, 10 April 1968, 15 speci- mens, collected by Peter M. Oringer, LACM locality 68-12. Type Material: Holotype, LACM 1539, 9 paratypes, LACM 1540, single paratypes, AMNH, ANSP, CAS, SDNHM, USNM. Discussion: Pyrgocythara angulosa has a shorter, less slen- der shell than P. melita (Dall, 1919), which has brown — markings on the shoulder and pillar, while P. angulosa has brown markings at the periphery and a white pillar. The name is a Latin adjective meaning full of corners, suggested by the angulate profile. 48. Daphnella gemmulifera McLean & Poorman, Spec. nov. (Figure 48) Description of Holotype: Shell of moderate size for the genus, characterized by its tabulate shoulder, constricted pillar and broadly flaring aperture; aperture more than Y% the length of the shell; color yellowish brown with broad areas of light and dark mottling, with white fleck- ing upon the spiral cords. Protoconch of 4 dark brown whorls with deeply impressed sutures, the first faintly spirally lirate, others with narrow axials descending ver- tically across the shoulder, diagonally reticulate at the periphery and below; postnuclear whorls 5. Axial ribs swollen and massive, 11 on first postnuclear whorl, in- creasing to 13 on the penultimate, completely obsolete THE VELIGER Vol. 14; No. 1 upon the final whorl; ribs arising at the shoulder and ex- tending diagonally to the suture below, crossed by 6 nar- row spiral cords on the first postnuclear whorl, increasing by intercalation to 14 on the final whorl above the sinus; base and pillar with numerous additional ribs, slightly uneven in thickness because of continual increase in number by intercalation; the concave shoulder weakly spirally lirate; last whorl with minute axial riblets, finely beaded at intersections with the spiral ribs. Sinus deep, reversed L-shaped, parietal callus wanting, end of sinus rounded, lower edge of sinus produced straight forward; lip edge thin (possibly immature), arcuate, anterior end of aperture broadly open, not differentiated into an an- terior canal; columellar area slightly sunken on the pillar. Height, 13.3, diameter, 5.4 mm. Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador (0°47’ S, 90°21’ W), 200 me- ters (110 fathoms), 5 December 1969, 2 specimens dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1541, 1 paratype, DeRoy Collection. The paratype measures: height, 12.2, diameter, 4.8 mm. Discussion: Of the Eastern Pacific species, Daphnella gemmulifera is the most tabulate at the shoulder and has the broadest, most flaring aperture. The name is Latin— of or pertaining to gems. 49. Daphnella retusa McLean & Poorman, spec. nov. (Figure 49) Description of Holotype: Shell of moderate size for the genus, whorls rounded, characterized by a thickened ma- ture lip, constricted pillar, and short anterior canal; aper- ture slightly more than % the length of the shell; color © yellowish white with faint brown markings, early whorls with a prominent white spiral cord. Protoconch of 4 dark brown whorls with deeply impressed sutures, tip small, faintly spirally lirate, the rest with narrow axials de- scending vertically across the shoulder, diagonally reticu- late at the periphery and below; postnuclear whorls 5. Axial ribs narrow, strongly projecting on early whorls, 7 on first postnuclear whorl, increasing to 14 on penulti- mate whorl, obsolete upon the final whorl; ribs arising at the shoulder below a concave but sloping subsutural channel, extending to the suture below, crossed by 3 strong spiral cords on first postnuclear whorl, increasing by intercalation to 10 above the aperture on final whorl, base and pillar with 15 additional cords, stronger and more evenly spaced on the pillar; last whorl with fine axial riblets, faintly overriding the spiral cords and pro- Vol. 14; No. 1 ducing beading at intersections. Sinus L-shaped, termi- nation rounded, parietal callus lacking; lip thickened be- hind the edge, anterior canal short, directed toward the left; columellar area slightly sunken on the pillar. Height, 12.4, diameter, 4.7 mm. : Type Locality: Off Loreto, Baja California, Mexico (26° 02’N, 116°16’ W), 20-40 fathoms, 29 August 1960, 1 specimen dredged by the Ariel Expedition, Shasky Col- lection. Type Material: Holotype, LACM 1542. Referred Material: Shasky Collection: Punta Final, Baja California. LACM: Mexico: Guaymas; Punta Arena, Baja California; Espiritu Santo Island; Cuastecomate, Jalisco; Guatulco Bay, Oaxaca. Panama: Tortola Island, Panama Bay. Discussion: Daphnella retusa is not uncommon in collec- tions, usually misidentified as D. allemani (Bartsch, 1931), from which it differs in having fewer spiral cords upon the final whorl, a more constricted pillar, and a short anterior canal, rather than having a widely flaring lip. It has also been misidentified as D. panamica Pilsbry & Lowe, 1932, which proves to be a synonym of D. mazatlanica, Pilsbry & Lowe, 1932, a species with an unconstricted pillar and widely flaring lip. 50. Rimosodaphnella deroyae McLean & Poorman, spec. nov. (Figure 50) Description of Holotype: Shell relatively large, early whorls with a strong spinose peripheral carination, later whorls rounded; anal fasciole sculptured only with curved growth lines; anterior canal elongate, twisted to the left; length of aperture % the length of the shell; color uni- formly tan. Protoconch small, whorls 3, the tip immersed, first 144 whorls spirally lirate and punctate, changing to diagonally reticulate, last half whorl developing a low peripheral carination that rises to median position and becomes the main carination of mature sculpture; post- nuclear whorls 7. Axial sculpture of 11 narrow ribs on early whorls, increasing to 18 on the final whorl, arising below the anal fasciole and fading on the base; the axial ribs intersected by equally narrow spiral cords, producing strong spines at intersections, with 2 major spinose spiral cords above the periphery and 2 more below, base with 5 additional weakly spinose cords; all interspaces between major cords with finely beaded, not spinose, cords; the constricted pillar with twisted spiral ridges continuous around the columella. Sinus L-shaped, deep, parietal THE VELIGER Page 111 callus lacking; lip edge thin, arcuate, leading into the elongate, unnotched anterior canal, canal twisted to the left; aperture with a thin glaze of blue callus, but other- wise translucent and excavated by the outward directed spines. Height, 26.2, diameter, 13.1 mm. Type Locality: Academy Bay, Isla Santa Cruz, Gala- pagos Islands, Ecuador (0°45’S, 90°48’ W), 200 meters (110 fathoms), 5 December 1969 and 15 January 1970, 4 specimens (3 immature and broken), dredged by André and Jacqueline DeRoy. Type Material: Holotype, LACM 1543, 3 paratypes, LACM 1544. Referred Material: LACM, 1 specimen from the south- ern coast of Isla Santa Cruz, dredged by the DeRoys. Discussion: Rimosodaphnella deroyae is unlike any other daphnelline species known to us. The type species of the genus, R. textilis (Brocchi, 1814), from the Italian Plio- cene, has rounded whorls and there is no indication of spinose sculpture, but the elongate canal is twisted to the left and the anal fasciole lacks spiral cording, exhibiting only raised growth lines. We provisionally refer R. de- royae to the genus. It is a pleasure to name this, the most spectacular of the new Galapagan turrids, for Jacqueline DeRoy (Mrs. André DeRoy), of Isla Santa Cruz, Gala- pagos Islands. 51. Philbertia shaskyi McLean & Poorman, spec. nov. (Figure 51) Description of Holotype: Shell small for the genus, char- acterized by massive axial ribs that undulate the sutures; whorls evenly rounded, length of aperture % the length of the shell; color creamy white. Protoconch of 4 dark brown whorls, the first spirally lirate and faintly punctate, the rest diagonally reticulate, changing abruptly to ma- ture sculpture; postnuclear whorls 5. Axial ribs massive, 9 on early whorls, 10 on final whorl, arising below the subsutural channel and and becoming obsolete upon the pillar; spiral cords narrow and low, increasing by inter- calation so that interspaces do not exceed the width of the cords, 5 on the penultimate whorl; body whorl and pillar with about 24 cords in advance of the aperture. Sinus sutural, relatively shallow, parietal callus lacking, lip thickened (edge broken in holotype), with an internal denticle below the sinus; anterior canal indicated by a deposition of callus at the base of the lip, canal short (tip broken in holotype), columella slightly sunken on the pillar. Height, 5.7, diameter, 2.5 mm. Page 112 Type Locality: Off SW end Isla Monserrate, Gulf of California (25°34’ N, 111°05’ W), 20-40 fathoms, 1 Sep- tember 1960, 1 worn specimen, dredged on the Ariel Ex- pedition, Shasky Collection. Type Material: Holotype, LACM 1545. Referred Material: LACM 68-27, 5 immature specimens, from siftings, rocky bottom, first cove north of Saladita Cove, Guaymas, Sonora, Mexico. Discussion: Philbertia shaskyi may not be confused with other daphnelline species. The genus Philbertia is char- acterized by a diagonally cancellate protoconch, coarse clathrate sculpture, thickened lip with internal denticles, and a short anterior canal. Philbertia doris Dall, 1919, qualifies in all respects except for the internal lip denti- tion, although a trace of it may be indicated. Philbertia shaskyi lacks lip denticles and also does not have the coarse clathrate sculpture, but is tentatively placed in Philbertia. Daphnella, s. s., is larger, lacks an anterior canal and axial sculpture is usually obsolete upon the final whorl. We are pleased to name this species for Donald Shasky, M.D., of Redlands, California, whose ex- tensive collection has filled in many gaps in the turrids. 52. Kermia informa McLean & Poorman, spec. nov. (Figure 52) Description of Holotype: Shell small for the genus, elon- gate cylindrical; chalky white, aperture glossy, translucent white. Protoconch of 4 translucent white whorls, tip small, the rest with low, narrow and sinuous axial riblets, gradually developing a peripheral bulge, the onset of ma- ture sculpture marked by the appearance of a peripheral carination and broader spacing of the axial ribs; post- nuclear whorls 5. Axial ribs 10 on early and later whorls, ribs narrow, extending from suture to suture, but reach- ing their crests on crossing the two equally narrow spiral cords on each whorl, beaded at intersections, and produc- ing deep squarish pits between; faint intercalary cords are present below the 2 main peripheral cords; base with 2 additional spiral cords; pillar with 3 massive spiral cords, the uppermost the largest; lip thickened by a massive varix, the spiral cording extending around it to the lip edge. Sinus moderately deep, entrance narrow, bordered on the inside by a parietal extension of the lip; lip faintly denticulate within, corresponding to the external cord- ing; anterior canal differentiated from the aperture by a constriction produced by lip callus, columella slightly sunken on the pillar. Height, 6.7, diameter, 2.5 mm. THE VELIGER Vol. 14; No. 1 Type Locality: Cartago Bay, Albemarle (Isabela) Island, Galapagos Islands, Ecuador (0°36'18” S, 90°57’11” W), 8— 10 fathoms, 25 January 1934, 5 specimens dredged by the R/V Velero, AHF station 187-34. Type Material: Holotype, LACM-AHF 1546, 2 para- types, LACM-AHF 1547, single paratypes, ANSP, USNM. Discussion: This is the first Eastern Pacific representative of this otherwise Indo-Pacific genus, differing from typical members in having coarser sculpture and not having spiral threading on the lower half of the protoconch whorls as indicated in the generic diagnosis. The name is Latin, misshapen or deformed. 53. Veprecula tornipila McLean & Poorman, spec. nov. (Figure 53) Description of Holotype: Shell small for the genus, char- acterized by tabulate whorls and a markedly twisted an- terior canal; color yellowish brown, the base and pillar brown. Protoconch relatively large, dark brown, whorls 4, first whorl smooth, the rest with thin axial riblets and minute spiral threads, not overriding the riblets; post- nuclear whorls 4. Axial ribs strong, projecting, with slightly broader interspaces, arising below the concave subsutural channel, fading on the base before reaching the tightly constricted pillar, 11 on first postnuclear whorl, 12 on final whorl, crossed by 3 strong spiral cords per whorl; cords overriding the axial ribs, beaded, almost spiny at intersections, base with 2 additional major cords; fine intercalary cords arise on the final whorl and are well developed on the back of the last whorl; pillar with 8 narrow, Closely spaced cords. Sinus sutural, deep; lip thin- edged, anterior canal nearly as long as the aperture (ap- parently chipped in the holotype), twisted to the left and reflexed. Height, 3.8, diameter, 1.8 mm. Type Locality: ‘Tagus Cove, Albemarle (Isabela) Island, Galapagos Islands, Ecuador (0°16’S, 91°22’ W), 80-100 fathoms, 15 January 1934, 1 specimen, grab sample by the R/V Velero, AHF bottom sample station 432. Type Material: Holotype, LACM-AHF 1548. Discussion: This is the first Eastern Pacific representative of Veprecula, an otherwise Indo-Pacific genus. The speci- men may not be fully mature; illustrations of other spe- cies of Veprecula show 5-6 whorls, while V. tornipila has but 4 postnuclear whorls. The name is a Latin compound noun meaning twisted pillar. Vol. 14; No. 1 THE VELIGER Literature Cited Keen, A. Myra 1958. Sea shells of tropical West America; marine mollusks from Lower California to Colombia. i-xi+624 pp.; 10 colored plts.; 1700 text figs. Stanford Univ. Press, Stan- ford. Calif. (5 December 1958) 1971. Sea shells of tropical West America; marine mollusks from Baja California to Peru. Second ed.; in press. Stanford, Calif. (Stanford Univ. Press) McLean, JaMEs HAMILTON 1971. _A revised classification of the family Turridae, with the proposal of new subfamilies, genera, and subgenera from the eastern Pacific. The Veliger 14 (1): 114-130; 4 plts. (1 July 1971) Suasky, Donatp R. 1971. Ten new species of tropical eastern Pacific Turridae. The Veliger 14 (1): 67-72; 1 plt. (1 July 1971) Page 113 Page 114 THE VELIGER Vol. 14; No. 1 A Revised Classification of the Family Turridae, with the Proposal of New Subfamilies, Genera, and Subgenera from the Eastern Pacific JAMES H. McLEAN Los Angeles County Museum of Natural History 900 Exposition Boulevard, Los Angeles, California 90007 (4 Plates) INTRODUCTION THE FAMILY TuRRIDAE is exceptionally large in genera and species. PowELL’s (1966) review of the 549 generic and subgeneric names proposed in the family, with illus- trations of type species of each accepted taxon, has greatly facilitated an approach to this large and otherwise un- wieldy family. Chiefly because of this impetus, I undertook a review of the tropical eastern Pacific members of the family as a contribution to the forthcoming revised edi- tion of Dr. A. Myra KEEN’s ‘‘Sea Shells of Tropical West America,” which is now in press. This paper is offered both to validate the new sub- families, genera, and subgenera utilized in the new edi- tion, and to present more fully my scheme of classifica- tion at the subfamily level, since this departs considerably from previous classifications. Because the classification is based extensively upon the radula, the paper also gives photographic illustrations of radular ribbons of numerous species in order to document this approach. Publication of the book will follow shortly. Since it will contain diagnoses and new photographs of each of the 295 species of Turridae now recognized in the Panamic Prov- ince, shell illustrations need not be included here. It will be assumed that the reader has access to POWELL’s (1966) monograph for a more complete understanding of the available genera. The differences between my con- cepts of many of these genera and those of previous authors are fully explained in the new edition and will not be re- peated here. Two papers validating new species of tropical eastern Pacific turrids are being published concurrently in this issue of the Veliger. In some cases the type species of the new taxa described herein are introduced as new species by McLEAn & PoorMAN (1971), describing 53 new species, or by Suasky (1971), describing 10 new species. ACKNOWLEDGMENTS My indebtedness, already mentioned, to Dr. A. W. B. Powell of the Auckland Museum, whose monograph pro- vided the groundwork, is here reaffirmed. His findings concerning New World genera were facilitated by Dr. J. P. E. Morrison of the U.S. National Museum, who made numerous radular slides for the late Dr. Paul Bartsch. Many of Morrison’s drawings were reproduced by Powell, and I too have been fortunate in being able to use both his slides and drawings. The continual aid of Mrs. Virginia Orr Maes of the Philadelphia Academy of Natural Sciences, a specialist in the Turridae, is gratefully acknowledged. Many of the critical radular preparations were hers. It should not be implied, however, that she necessarily agrees with all of my conclusions. I particularly wish to acknowledge the constant en- couragement and help of Dr. Myra Keen, of Stanford University. Evaluation of available names at the specific level has been possible because photographs of type specimens in the principal museums were on hand. Dr. Myra Keen has provided photographs of type specimens in the British Museum, supplemented by others taken by Virginia Maes. I have personally examined and photographed type ma- terial at the U. S. National Museum, Washington, D.C.; American Museum, New York; Academy of Natural Sci- Vol. 14; No. 1 ences, Philadelphia; California Academy of Sciences, San Francisco; Stanford University, California; and the San Diego Museum, California. I am grateful to the curators and staffs of these institutions for the many courtesies ex- tended, both on my visits and in correspondence. Excellent material in the family Turridae is available in the Los Angeles County Museum of Natural History. In addition to the Museum’s holdings, the Hancock Col- lection, resulting from expeditions of the Allan Hancock Foundation, and now on loan to the Museum, has proven exceptionally rich in turrids. Several private collections, notably those of Helen DuShane of Whittier, Leroy Poor- man of Pasadena, and Donald Shasky of Redlands, Cali- fornia, have yielded much information. THe TURRID RADULA AND FEEDING MECHANISM There are essentially two basic radular types in the Tur- ridae. In the first group, the radular ribbon has a strong basal membrane, and the teeth consist of a singly cusped rachidian, a rachiglossate lateral, and a slender marginal, although many genera retain only the marginal teeth. The marginal teeth are solid in structure, some simple in form, while others appear to have two limbs, the lesser member fused to the greater member at the tip. In the second radular group there are marginal teeth only, which are hollow and truly toxoglossate, used singly as hypo- dermic needles to paralyze prey, as in the family Conidae. Here the teeth are also on a ribbon, but the basal mem- brane is vestigial and the teeth easily detached (Mags, IOWANS 7A) Feeding mechanisms in the two groups differ markedly. Mags (op. cit.) has offered a clear explanation of the major distinctions, which may be summarized as follows: En- venomation in the non-toxoglossates is assumed to take place in the buccal cavity after the prey has been swal- lowed. The radular ribbon has a “working bend” at the opening into the buccal cavity, where the teeth are used a row at a time and then sloughed off. In the toxoglossates the teeth are sloughed off the vestigial membrane of the ribbon, but rather than being lost are stored in a mem- branous pouch opening narrowly into the buccal cavity; a single tooth may be squeezed out, charged with toxin, and held at the tip of the proboscis, envenomation taking place upon contact with the prey outside the buccal cavity. Thus it is clear that the differences between the two groups involve far more than simple differences in radular teeth; the structure and function of the entire buccal cavity differs in the two groups. Very little is known about THE VELIGER Page 115 the specific details of feeding, but it is likely that many modifications and specializations occur, considering the extensive diversity known in shell morphology and radular types. SUBFAMILY CLASSIFICATION oF TURRIDAE THIELE (1929) grouped the turrids in the family Conidae, using three subfamilies: Turrinae, Brachytominae, and Cytharinae; the Coninae constituting the fourth sub- family. His Turrinae included all the non-toxoglossate genera, the Brachytominae the operculate toxoglossates, and the Cytharinae the inoperculate toxoglossates. A sepa- ration between the toxoglossate and nontoxoglossate groups is definitely indicated, but division of the opercu- late and inoperculate toxoglossates will not yield natural groups, because the operculum may be fully developed, vestigial, or lacking in some closely related genera. Ap- plication of Brachytominae was unfortunate, because the opercular and radular characters of the type species of Brachytoma Swainson, 1840 (Pleurotoma strombiformis Sowerby, 1839 = P. stromboides Sowerby, 1832), remain unknown (PowELL, 1966: 89).’ Usage of Brachytominae * HaseE & Kosuce (1966, p. 336, pl. 29, fig. 5) described a Brachy- toma vexillum from Formosa, a species here considered con- generic with the type species B. stromboides (Sowerby, 1832) (original figure reproduced by Powe tt, 1966, pl. 13, fig. 21). The Habe & Kosuge species is operculate and has a subsutural cord, suggesting that the radula of Brachytoma will prove to be either zonulispirine, or more likely, crassispirine, as defined in this paper. has therefore been avoided by subsequent authors. PowELL (1942, 1966) offered classifications employing a number of subfamilies, but relied chiefly on shell char- acters in defining them. In several instances there are disparate radular types within a single subfamily, some in- cluding both the solid and hollow marginal teeth. He felt that toxoglossate dentition could develop independently in different groups. His view is summarized as follows (1966: 55): “The ability to develop this highly specialized use of the radula for predaceous purposes is apparently in- herent in all the subfamily groups of the Turridae to a varying extent. .. .’ The view that groups having the disparate radular types may be closely related is rejected here and by Morrison and Maes as discussed below. Morrison (1966) evidently followed Thiele in finding a distinction based on those with solid and those with hollow marginal teeth, but he suggested separation at the family level, utilizing Turridae for those with solid teeth, and introducing Mangeliidae for those with the hollow, toxoglossate teeth. He employed only a few additional Page 116 subfamilies to account for further radular distinctions. However, I feel that separation at the family level is pre- mature since details of the feeding mechanisms and func- tional anatomy are known for few species. The fact that all turrids possess a venom gland and that most are easily recognized as turrids on the conchological character of the anal sinus argues for the retention of a single family. Mor- rison’s statement that the toxoglossate group lacks a radu- lar membrane is not supported by Mass (1971), who de- scribes the basal membrane as vestigial. Maes (op. cit.) affirmed the basic distinction between the toxoglossate and non-toxoglossate groups and offered new insights about the phylogeny of the toxoglossates. She did not attempt a new subfamily classification, al- though she did suggest some modifications of the subfamily definitions of both Powell and Morrison. I offer here a classification that employs more sub- families than utilized by Powell or Morrison, defined both on radular features and shell characters. No subfamily in my scheme contains genera with disparate radular types, at least not combining those with solid and those with hollow teeth. Shell characters, however, are not always clear-cut, and somewhat similar shell forms may appear in different subfamilies. My classification has its limitations in that I have, for the most part, not considered or attempted to assign ge- neric groups unrepresented in the eastern Pacific. My ob- jective has been to present a workable arrangement of the large eastern Pacific fauna, for the tropical element of which I employ a total of 95 genera arranged in 12 sub- families. A workable arrangement can be offered now, on the basis of shell characters such as the protoconch, pres- ence or absence of columellar plicae, parietal callus, posi- tion of the anal sinus, presence or absence of the opercu- lum, and the radula, despite the paucity of other informa- tion on anatomy. The salient features of the 12 subfamilies are summarized in Table 1. Three subfamilies recognized by Powell, the Clavatu- linae, Conorbinae, and Thatcheriinae, are not repre- sented in the eastern Pacific. While I believe that the 549 generic names discussed by Powell may be assigned to the 15 proposed subfamilies (including the 3 not represented in the eastern Pacific), it will behoove workers dealing with the family to make further modifications. Other schemes of ranking may eventually be utilized, perhaps by demoting some groups with overlapping radular features to the status of tribes, saving the subfamily category for more fundamental, perhaps yet unknown, distinctions. THE VELIGER Vol. 14; No. 1 Subfamily PsEUDOMELATOMINAE Morrison, 1966 (Figures J to 3) Diagnosis: Shells of medium to large size, anterior canal moderately elongate; anal sinus on the shoulder slope, parietal callus lacking, columella smooth. Protoconch smooth. Operculum leaf shaped, with terminal nucleus. Radular ribbon relatively large, rachidian tooth large, with rectangular base and strong central cusp, marginal tooth massive, tapered to a sharp point, lacking a smaller limb. Discussion: Three genera comprise the Pseudomelatomi- nae, all confined to the eastern Pacific: Pseudomelatoma Dall, 1918; Hormospira Berry, 1958; and Tuiariturris Berry, 1958. The radula (Figures J to 3) is distinctive, par- ticularly in lacking the smaller limb of the marginal tooth found in most of the non-toxoglossate groups. PowELL (1966) allocated these genera to the Turricu- linae on the basis of shell characters. Morrison (1966) designated a subfamily, suggesting placement of the group as a subfamily of the Muricidae or Thaisidae, evidently because he interpreted the outer teeth as laterals rather than marginals, and considered the radula “completely unrelated in structure and function” to that of other tur- rids. However, the shell exhibits a turrid sinus and a turrid poison gland is present (MAEs, personal communication). I follow the suggestion of Maes in interpreting the outer teeth as marginals and recognize a subfamily, in the ab- sence of further published information about the anatomy and function. Subfamily CLAVINAE Powell, 1942 (Figures 4 to 26) Diagnosis: Shells of moderate to large size, high spired, with short or moderately elongate anterior canals; ground color usually light, surface often glossy. Protoconch smooth or strongly carinate. Sinus deep, bordered on the inside by parietal callus; columella smooth. Operculum leaf shaped, with terminal nucleus. Radula typically with a small, unicuspid rachidian, lacking a broad rectangular base; laterals broad, comblike; marginals long and flat- tened, lesser limb small. Discussion: The subfamily limitation used here was first proposed by Morrison (1966), who unnecessarily intro- Vol. 14; No. 1 duced a subfamily name, Drilliinae, rather than restrict the earlier Clavinae. Mars (1971) referred to the group as Clavinae ‘“‘of Maes unpublished, not of Powell, 1966.” As limited by Morrison, Maes, and in the present usage, this is the only group exhibiting the rachiglossate, comb- like lateral teeth, a type of dentition described by Powell as “prototypic.” However, that may be an unfortunate appellation, because the presence of lateral teeth may well be primitive, but not necessarily an ancestral character. Powell’s concept of Clavinae embraced genera with diverse radular types, including a number of toxoglossate groups. Such genera, many of which have raised subsutural cords, are assigned to other subfamilies. Eastern Pacific genera with carinate protoconchs are Calliclava, new genus; Elaeocyma Dall, 1918; Kylix Dall, 1919; Imaclava Bartsch, 1944; and Leptadrillia Woodring, 1928. Genera lacking the carination are Syntomodrillia Woodring, 1928; Agladrillia Woodring, 1928; Drillia Gray, 1838 (and subgenus Clathrodrillia Dall, 1918); Globidrillia Woodring, 1928; Cerodrillia Bartsch & Reh- der, 1939; Splendrillia Hedley, 1922; Ivedalea Oliver, 1915; Bellaspira Conrad, 1868; and the deep water genus Sptrotropis G. O. Sars, 1878. The clavine lateral is most frequently laterally elongate with numerous cusps as in Kylix (Figures 9 to 11) and most of the others illustrated. In Imaclava (Figures 12 to 13) there is a vertical elongation of the lateral, which is carried to an extreme in the new genus Calliclava (Figures # to 7), in which the number of cusps on the lateral is markedly reduced. The length of the marginal varies and in Bellaspira (Figure 26) a marked curvature is noticable. Clavine genera may be recognized on shell characters in having a whitish ground color, the surface usually glossy, spiral sculpture consisting of incised striae. Generic cri- teria are: 1) protoconch whorls, which may be smooth or carinate, 2) length of anterior canal, and whether nearly straight or at an angle to the edge of the outer lip, 3) back of last whorl—axial ribbing may be normal or obsolete, and there may be a massive hump, and 4) anal sinus, which may be projecting or closely appressed, some having a weak slot directed toward the suture just behind a tubercle of parietal callus. Calliclava McLean, gen. nov. Type Species: Cymatosyrinx palmeri Dall, 1919. Diagnosis: Shell small to medium sized, body whorl rela- tively short, shell surface glossy, often with brown or pink banding. Protoconch large, whorls 2, strongly carinate THE VELIGER Page 117 from the beginning. Axial ribbing weak across the shoulder, tending to form nodes at the periphery, spiral sculpture of incised grooves. Sinus deep, U-shaped, bor- dered by curved parietal callus on the inside. Lip edge nearly straight, stromboid notch moderately deep, mature lip preceded by a thickened axial rib %4 turn back; anterior canal short, deeply notched. Operculum leaf shaped, nu- cleus terminal. Rachidian tooth of radula small, the lateral tooth vertically compressed, with relatively few cusps (Figures # to 7). Discussion: Calliclava is distinguished from all other clavine genera in having a strongly carinate protoconch from the emergent tip and in having a radula with a com- pressed rather than elongate lateral tooth. The character- istic radula is found in no other genus known to me, nor is a clavine genus known in which the carination is evident upon the immediately emergent nuclear tip. In general proportions and sculpture Calliclava resem- bles Elaeocyma, in which the carination of the protoconch emerges only upon the second nuclear whorl. The radula of Elaeocyma, type species E. empyrosia (Figure 8), is typically clavine, with an elongate lateral tooth. Ten tropical eastern Pacific species are assigned to Calliclava (see MCLEAN in KEEN, 1971) and the group is restricted to the eastern Pacific, as far as is known. Radu- lae of four species of Calliclava are illustrated (Figures 4 to 7). Subfamily TurrinaE Swainson, 1840 (Figures 27 to 29) Diagnosis: Shells of medium to large size, anterior canal moderately elongate, anal sinus on the peripheral keel, parietal callus lacking, columella smooth, protoconch smooth. Operculum leaf shaped, with terminal nucleus. Radula with or without a small, or well-developed, uni- cuspid, rectangular central tooth, marginal teeth wish- bone shaped, or of the modified wishbone type with the distal limb severed. Discussion: Powe.i’s (1966) concept of the subfamily Turrinae is followed. The group is characterized in hav- ing the anal sinus on the peripheral keel, rather than on the shoulder, as in the closely related Turriculinae. Morrison (1966) introduced a subfamily name Lophi- otominae, which may be synonymized with Turrinae because Lophiotoma Casey, 1904, is typically turrine. However, Morrison’s concept of Lophiotominae was much broader, embracing all non-toxoglossate genera that lack central and lateral teeth. Page 118 The subfamilies Turrinae, Turriculinae, and Clava- tulinae (an African group) are defined chiefly on shell characters. Radular characters overlap. In all three groups the marginal teeth may be of the wishbone type, modified wishbone—with severed distal limb, or duplex—with small accessory limb. In some closely related genera, or even species in the same genus such as Gemmula (see PowELL, 1966: 47), a central may be present or absent. A subfamily distinction on the presence or absence of a THE VELIGER Vol. 14; No. 1 central tooth, as proposed by Morrison, cannot be made. Eastern Pacific genera of Turrinae are Gemmula Wein- kauff, 1875; Polystira Woodring, 1928; Cryptogemma Dall, 1918; and Ptychosyrinx Thiele, 1925, which was introduced in the eastern Pacific by Berry (1968: 158) with the description of P. chilensis. PowELL (1964, 1966) has included Antiplanes Dall, 1902 (and subgenera), and Carinoturris Bartsch, 1944, in the Turrinae, genera here considered more appropriately referred to Turriculinae. Plate Explanation Note: Slides of the radulae illustrated here are in 3 collections: LACM, Los Angeles County Museum of Natural History; USNM, United States National Museum of Natural History; ANSP, Aca- demy of Natural Sciences, Philadelphia. The AHF (Allan Hancock Foundation) Collection is on loan to LACM. LACM slides were made from mature specimens or large speci- mens lacking a mature lip, mounted and stained in non-resinous medium (Turtox CMC-10, stained with a dab of CMC-S) ; ANSP Subfamily Pseudomelatominae Figure 1: ' Pseudomelatoma penicillata (Carpenter, 1864). AHF 2603-54, Punta San Bartolome, Baja California. Figure 2: 'Hormospira maculosa (Sowerby, 1834). LACM 65-16, Banderas Bay, Nayarit, Mexico, 10 to 15 fathoms. Figure 3: Tiariturris libya (Dall, 1919). USNM 96576, Cape San Lucas, Baja California, 66 fathoms. Clavinae Figure 4: Calliclava aegina (Dall, 1919). LACM 65-43, Bahia de Los Angeles, Baja California, 10 to 20 fathoms. Figure 5: Calliclava craneana (Hertlein « Strong, 1951). LACM, Salina Cruz, Oaxaca, Mexico, 20 to 50 fathoms. Figure 6: Calliclava jaliscoensis McLean « Poorman, 1971. LACM 65-16, Banderas Bay, Nayarit, Mexico, 10 to 15 fathoms. Figure 7: 1 Calliclava palmeri (Dall, 1919). LACM A.7740, Puer- tocitos, Baja California. Figure 8: 7 Elaeocyma empyrosia (Dall, 1899). AHF 913-39, San Clemente Island, California, 35 to 46 fathoms. Figure 9: Kylix halocydne (Dall, 1919). AHF 1160-40, Long Beach, California, 32 to 52 fathoms. Figure 10: Kylix hecuba (Dall, 1919). AHF 721-37, Puerto Pefias- co, Sonora, Mexico, 8 to 12 fathoms. Figure 11: Kylix paziana (Dall, 1919). LACM, Guaymas, Sonora, Mexico, 17 fathoms. Figure 12: Imaclava pilsbryi Bartsch, 1950. LACM 68-58, Bahia Santiago, Colima, Mexico, 7 to 12 fathoms. Figure 13: ™Imaclava unimaculata (Sowerby, 1834). LACM 66- 17, Rancho Palmilla, Baja California, 10 to 20 fathoms. Figure 14: Agladrillia flucticulus McLean & Poorman, 1971. LA CM, Gulf of Tehuantepec, Chiapas, Mexico, 20 to 40 fathoms. Figure 15: Agladrillia pudica (Hinds, 1843). AHF 214-34, Cape San Francisco, Ecuador, 2 fathoms. Figure 16: Drillia (Drillia) acapulcana (Lowe, 1935). AHF 535-36, Bahia de Los Angeles, Baja California, 25 to 40 fathoms. Subfamily slides made by Virginia Maes are unstained; stain in some of the USNM slides made by J. P. E. Morrison has coagulated. Magnification of all figures is the same, approximately 450, thereby facilitating comparison by relative size. The arrangement follows the sequence used by McLEan (in KEEN, 1971), with but few exceptions, and with the addition of some species from the Californian and Oregonian Provinces. A superior T (7) preceding the name indicates that the species is the type species of the genus or subgenus. Figure 17: Drillia (Drillia) albicostata (Sowerby, 1834). AHF 325- 35, Tagus Cove, Isabela Island, Galapagos Islands, 80 fathoms. Figure 18: Drillia (Drillia) clavata (Sowerby, 1834). LACM, James Bay, Santiago Island, Galapagos Islands, 11 fathoms. Figure 19: Drillia (Drillia) roseola (Hertlein « Strong, 1955). LA CM 68-58, Bahia Santiago, Colima, Mexico, 7 to 12 fathoms. Figure 20: Drillia (Clathrodrillia) salvadorica (Hertlein & Strong, 1951). LACM 68-58, Bahia Santiago, Colima, Mexico, 7 to 12 fms. Figure 21: Globidrillia hemphilli (Stearns, 1871). USNM 268762, San Bartolomé Bay, Baja California. Figure 22: Globidrillia micans (Hinds, 1843). LACM, Puertocitos, Baja California, 6 to 8 fathoms. Figure 23: Globidrillia strohbeeni (Hertlein « Strong, 1951). LA CM 66-20, El Pulmo, Baja California, 4 fathoms. Figure 24: Cerodrillia cybele (Pilsbry « Lowe, 1932). LACM 65-16, Banderas Bay, Nayarit, Mexico, 10 to 15 fathoms. Figure 25: Splendrillia bratcherae McLean x Poorman, 1971. US NM 268911, Agua Verde Bay, Baja California. Figure 26: Bellaspira melea Dall, 1919. LACM, Guaymas, Sonora, Mexico, 17 fathoms. Subfamily Turrinae Figure 27: ?Gemmula hindsiana Berry, 1958. LACM 60-9, Guay- mas, Sonora, Mexico, 40 to 125 fathoms. Figure 28: Polystira oxytropis (Sowerby, 1834). AHF 941-39, Gulf of Dulce, Costa Rica, 19 to 48 fathoms. Figure 29: Cryptogemma quentinensis Dall, 1919. USNM 214068, off San Diego, California, 822 fathoms. Turriculinae Figure 30: 1 Fusiturricula armilda (Dall, 1908). LACM, Bahia Bamba, Oaxaca, Mexico, 25 to 50 fathoms. Figure 31: Cochlespira cedonulli (Reeve, 1843). USNM 123102, Gulf of Panama, 153 fathoms. Figure 32: Knefastia tuberculifera (Broderip « Sowerby, 1829). USNM 96648, La Paz, Baja California, 21 fathoms. Subfamily [McLean] Figures 1 to 32 Tue VELIGER, Vol. 14, No. 1 . = ~ SY —\ = | ‘ = ~ a : JRE ORES aS St i ee Y E t a cy P- SEF Ze < Z, 3 cy eo Ay 7 G at SY Vol. 14; No. 1 Gemmula hindsiana, the type species of Gemmula, has wishbone shaped marginals with a central tooth (Figure 27); Polystira oxytropis (Figure 28) is similar but lacks a central, and Cryptogemma quentinensis (Figure 29) has slender wishbone marginals with a detached distal limb. Subfamily TurricuLinaE Powell, 1942 (Figures 30 to 43) Diagnosis: Shells of medium to large size, anterior canal moderately elongate, somewhat flexed, anal sinus on the shoulder, usually deep, J-shaped or U-shaped; parietal callus lacking, early whorls of protoconch smooth. Oper- culum leaf shaped, nucleus usually terminal. Radula with or without a small or well developed, unicuspid, rectan- gular central tooth; marginal teeth wishbone shaped, or of the modified wishbone type with the distal limb severed, Discussion: The subfamily limitation employed here fol- lows PowELt’s concept (1966, 1969), the group distin- guished from Turrinae in having the sinus on the shoul- der rather than on the peripheral keel. Cochlespirinae Powell, 1942, is synonymous. It was intended originally to apply to genera having a broad based, unicuspid rach- idian. Powe t later retracted it (1966) upon noting that the presence or absence of a rachidian varies extensively in the Turrinae and Turriculinae, as discussed above. Shallow water genera of the tropical Eastern Pacific are Fusiturricula Woodring, 1928; Cochlespira Conrad, 1865; Knefastia Dall, 1919; and Pyrgospira, new genus. Northeastern Pacific genera are Aforia Dall, 1889; Anti- planes Dall, 1902 (and subgenera Rectiplanes Bartsch, 1944; and Rectisulcus Habe, 1958); Carinoturris Bartsch, 1944; Megasurcula Casey, 1904; and Rhodopetoma Bartsch, 1944. Abyssal genera are Aforia Dall, 1889; Anticlinura Thiele, 1934; Leucosyrinx Dall, 1889; and Steiraxis Dall, 1896. In Antiplanes and Carinoturris the sinus is relatively low on the shoulder, but not ona raised peripheral keel as in the Turrinae, where these genera were assigned by Powe tt (1964, 1966). A rachidian tooth with rectangular base is found in Cochlespira cedonulli (Figure 31) and Aforia (Figures 34 to 35); other genera have wishbone shaped marginals only, some are broad with the small distal limb detached as in Knefastia tuberculifera (Figure 32), others narrow as in Fusiturricula armilda (Figure 30), and in the new genus Pyrgospira (Figure 33), the secondary limb is greatly reduced. THE VELIGER Page 119 Pyrgospira McLean, gen. nov. Type Species: Pleurotoma obeliscus Reeve, 1843 (Syno- nyms: Clathrodrillia aenone Dall, 1919; Crassispira tom- lintiana Melvill, 1927; Clathrodrillia nautica Pilsbry & Lowe, 1932). Diagnosis: Shell of small to medium size, yellowish with brown periostracum, high spired, whorls tabulate below a concave shoulder bearing a raised subsutural thread. Protoconch of 2 smooth whorls, passing gradually to ma- ture sculpture. Axial ribbing numerous on early whorls, crossed by spiral cords, producing a coarse clathrate sculp- ture across the body whorl. Sinus on the shoulder slope, narrow at the entrance, moderately deep, its termination U-shaped; parietal callus lacking except for a slight thick- ening in mature specimens. Anterior canal moderately elongate, deeply notched, stromboid notch moderately deep, lip crenulated by the spiral sculpture, inner lip projecting over the curved siphonal fasciole. Operculum leaf shaped, nucleus terminal. Radula with marginal teeth only, of modified wishbone type, main limb of tooth massive, distal limb small and narrow (Figure 33). Discussion: Pyrgospira has a shorter canal than most tur- riculine genera, but lacks the development of parietal callus and the thickened rib on the back of the last whorl that characterizes most crassispirine genera. The radula is distinctive. In addition to the wide ranging eastern Pacific type species, Pyrgospira obeliscus, there are two Atlantic rep- resentatives, P. ostrearum (Stearns, 1872) and P. tam- paensis (Bartsch & Rehder, 1939), as pointed out by Vir- ginia Maes. The typical radula also occurs in these species. Subfamily CrassisPiRINAE Morrison, 1966 (Figures 44 to 71) Diagnosis: Shells of medium to large size, with well de- veloped parietal callus about the sinus and usually a nar- row, projecting subsutural fold, the shoulder area other- wise sculptured only by growth lines. Protoconch smooth- whorled at first, often developing fine axial riblets before passing to the mature sculpture. Body whorl sculptured with axial ribs and spiral cords. Operculum leaf shaped, with terminal nucleus. Radula rarely with a rachidian tooth, usually of marginals only, of the modified wishbone type with the distal limb severed, or the duplex type, in which a narrow, much smaller accessory limb is super- imposed on the larger main member. Page 120 THE VELIGER Vol. 14; No. 1 Discussion: PoweLt (1966) grouped the crassispirine genera in the Clavinae because of similarities in shell char- acters. Morrison (1966) introduced Crassispirinae as an alternative name for Lophiotominae, in which he placed all non-toxoglossate genera that lack central and lateral teeth, as discussed above under Turrinae. Mags (1971) referred to the Crassispirinae: “in part of Morrison, 1966,” but did not offer a diagnosis. Crassispirinae is here restricted to apply to genera with strong parietal callus about the sinus and a radula that usually lacks a rachidian and has a modified wishbone or duplex type of marginal. Crassispira Swainson, 1840, is the most characteristic New World group. Eight additional subgenera defined chiefly on the structure of the sinus are recognized: ~ (Glossispiva), new subgenus; Burchia Bartsch, 1944; (Crassiclava), new subgenus; Crassispirella Bartsch & Rehder, 1939; (Gibbaspira), new subgenus; Dallspira Bartsch, 1950; Striospira Bartsch, 1950; and Monilispira Bartsch & Rehder, 1939. The type species of Monilispirva is Driliia monilifera Carpenter, 1857, not M. monilis Bartsch & Rehder, 1939, as was indicated by POWELL (1966). This distinction significantly changes the concept Plate Explanation Subfamily Turriculinae (continued) Figure 33: 1 Pyrgospira obeliscus (Reeve, 1843). LACM A.6573, Tastiota, Sonora, Mexico. 35 to 45 fathoms. Figure 34: Aforia goodei (Dall, 1890). LACM A.8998, Queen Charlotte Sound, British Columbia, 1050 fathoms. Figure 35: Aforia kincaidi (Dall, 1919). Holotype, USNM 151581, Shelikof Strait, Kodiak Island, Alaska. Figure 36: “Leucosyrinx” clionella Dall, 1908. USNM 97069, off Manta, Ecuador, 401 fathoms. Figure 37: “Leucosyrinx” exulans (Dall, 1890). Holotype, USNM 96499, Galapagos Islands, 634 fathoms. Figure 38: Leucosyrinx equatorialis (Dall, 1919). USNM 97070, off Manta, Ecuador, 401 fathoms. Figure 39: 1 Antiplanes (Rectiplanes) santarosana (Dall, 1902). AHF 1396-41, San Miguel Island, California, 57 fathoms. Figure 40: Antiplanes (Rectisulcus) strongi (Arnold, 1903). AHF 1384-41, Santa Catalina Island, California, 108 fathoms. Figure 41: 1 Carinoturris adrastia (Dall, 1919). Paratype, USNM 226154a, Monterey Bay, California, 581 fathoms. Figure 42: ™Rhodopetoma rhodope (Dall, 1919). Holotype, US NM 212361, Santa Rosa Island, California, 82 fathoms. Figure 43: 1? Megasurcula carpenteriana (Gabb, 1865). AHF 1141- 40, El Segundo, California, 28 to 30 fathoms. Subfamily Crassispirinae Figure 44: Crassispira (Crassispira) maura (Sowerby, 1834). LA CM 68-58, Bahia Santiago, Colima, Mexico, 7 to 12 fathoms. Figure 45: + Crassispira (Glossispira) harfordiana (Reeve, 1843). LACM 70-16, Veracruz, Panama. Figure 46: * Crassispira (Burchia) semiinflata (Grant & Gale, 1931). LACM 65-2, Point Fermin, Los Angeles County, California, 16 fms. Figure 47: Crassispira (Burchia) unicolor (Sowerby, 1834). LACM 70-15, Venado Island, Panama Canal Zone. Figure 48: Crassispira (Crassiclava) cortezi Shasky « Campbell, 1964. LACM 60-6, Espiritu Santo Island, Gulf of California, 40 to 90 fathoms. Figure 49: ! Crassispira (Crassiclava) turricula (Sowerby, 1834). AHF 1031-40, Santa Maria Bay, Baja California, 25 to 22 fathoms. Figure 50: Crassispira (Crassispirella) ballenaensis Hertlein «& Strong, 1951. LACM, Gulf of Fonseca, El Salvador, 18 to 45 fms. Figure 51: Crassispira (Crassispirella) brujae Hertlein « Strong, 1951. LACM 38-6, Chamela Bay, Jalisco, Mexico. Figure 52: Crassispira (Crassispirella) chacei Hertlein « Strong, 1951. LACM 60-9, Guaymas, Sonora, Mexico, 40 to 125 fathoms. Figure 53: Crassispira (Crassispirella) discors (Sowerby, 1834). LA CM 68-41, Cuastecomate, Jalisco, Mexico, 15 to 65 feet. Figure 54: Crassispira (Crassispirella) epicasta Dall, 1919. LACM 70-15, Venado Island, Panama Canal Zone (ANSP, slide). Figure 55: 1 Crassispira (Crassispirella) rugitecta (Dall, 1918). AHF 1259-41, Dewey Channel, Baja California, 49 fathoms. Figure 56: Crassispira (Crassispirella) rustica (Sowerby, 1834). LA CM 70-15, Venado Island, Panama Canal Zone. Figure 57: 1 Crassispira (Gibbaspira) rudis (Sowerby, 1834). LA CM 70-16, Veracruz, Panama. Figure 58: 1 Crassispira (Dallspira) abdera (Dall, 1919). LACM 70-15, Venado Island, Panama Canal Zone. Figure 59: Crassispira (Dallspira) bifurca (E. A. Smith, 1888). LA CM 67-17, Libertad, Sonora, Mexico. Figure 60: Crassispira (Dallspira) cerithoidea (Carpenter, 1857). LACM 68-41, Cuastecomate, Jalisco, Mexico, 15 to 65 feet (AN SP, slide). Figure 61: Crassispira (Dallspira) coelata (Hinds, 1843). LACM 70-15, Venado Island, Panama Canal Zone (ANSP, slide). Figure 62: Crassispira (Dallspira) eurynome Dall, 1919. LACM, Mazatlan (ANSP, slide). Figure 63: Crassispira (Dallspira) martiae McLean « Poorman, 1971. Paratype, LACM 70-15, Venado Island, Panama Canal Zone. Figure 64: 1 Crassispira (Striospira) kluthi E. K. Jordan, 1936. LA CM 70-16, Veracruz, Panama. Figure 65: Crassispira (Striospira) nigerrima (Sowerby, 1834). LA CM 66-18, Punta Gorda, Baja California, 10 to 20 fathoms. Figure 66: Crassispira (Striospira) tepocana Dall, 1919. AHF 535- 36, Bahia de Los Angeles, Baja California, 25 to 40 fathoms. Figure 67: Crassispira (Striospira) xanti Hertlein « Strong, 1951. LACM 66-18, Punta Gorda, Baja California, 10 to 20 fathoms. Figure 68: Crassispira (Monilispira) appressa (Carpenter, 1864). LACM 66-15, Rancho El Tule, Baja California. Figure 69: Crassispira (Monilispira) currani McLean & Poorman, 1971. Paratype, LACM 70-4, Sayulita, Nayarit, Mexico. Figure 70: 1 Crassispira (Monilispira) monilifera (Carpenter, 1857). LACM, Mazatlan. Figure 71: Crassispira (Monilispira) pluto Pilsbry « Lowe, 1932. LA CM 67-17, Libertad, Sonora, Mexico. 4 =e SNS mn —~ ~ et N Pad [McLean] Figures 33 to 71 Ce FF Lb 4 ge es f G THE VELIGER, Vol. 14, No. 1 Vol. 14; No. 1 of Monilispira, which has been used for species here placed in Pilsbryspira Bartsch, 1950, a toxoglossate group. Other Crassispirine genera represented in the eastern Pacific are Hindsiclava Hertlein & Strong, 1955; Doxo- spira, new genus; Buchema Corea, 1934; Lioglyphostoma Woodring, 1928; Maesiella, new genus; Miraclathurella Woodring, 1928; and Carinodrillia Dall, 1918. Radulae of most of the eastern Pacific species of Crassi- spira are shown in Figures 44 to 71. Of particular interest is the presence of a rachidian tooth in both species of the new subgenus Crassiclava (Figures 48 to 49), the only crassispirine group known to have a rachidian tooth. Par- ticularly small ribbons are found in three species of the subgenus Striospira (Figures 64 to 65, 67). Two species allocated to the subgenus Crassispirella, C. discors (Fig- ure 53) and C. rustica (Figure 56) have teeth most resem- bling those of Pyrgospira obeliscus (Figure 33), in which the secondary limb is reduced. Lioglyphostoma (Figures 75 to 76) and Miraclathurella (Figures 79 to 80) have been regarded by previous authors as related to the toxoglossate genus Glyphostoma, but are, in fact, operculate with duplex dentition. The genus Carinodrillia (Figures 81 to 85) has a marginal tooth with a long, flattened main member and a much reduced (if detectable at all) secondary limb, thereby resembling the marginal of the Clavinae. However, on shell characters Carinodrillia is allocated to the Crassispirinae and the modified lateral tooth interpreted as a duplex derivative. (Glossispira) McLean, subgen. nov. (of Crassispira Swainson, 1840) Type Species: Pleurotoma harfordiana Reeve, 1843 (Syn- onym: Crassispira adamsiana Pilsbry & Lowe, 1932). Diagnosis: Shell relatively large and high spired; subsu- tural cord raised, weakly noded, shoulder concave below; periostracum thin, light brown; color gray with irregular white mottling. Protoconch white, whorls 2, smooth. Ma- ture sculpture of narrow axial ribs and spiral cords, coarsely beaded at intersections; entire shell finely spirally striate. Sinus relatively shallow, entrance narrow, poste- rior part of aperture narrowed above the sinus into a ver- tical slot; lip edge forming a projecting tongue between the sinus and vertical slot. Lip edge thin, strengthened behind by a massive axial rib, stromboid notch shallow. Anterior canal short, deeply notched, inner lip callus slightly raised above the siphonal fasciole. Operculum leaf shaped, nucleus terminal. Radula of the duplex type (Figure 45). THE VELIGER Page 121 Discussion: The infolded tonguelike extension of the lip between the sinus and the sutural slot is the characteristic feature of Glossispira. The subgenus Crassispira, s.s., seems to be the most closely related. It has a sutural slot, but the sinus entrance is broad and the infolded extension of the lip is lacking. The surface of Crassispira, s.s., differs in having a glossy, closely adherent dark periostracum. In surface texture, C. (Glossispira) harfordiana most resem- bles C. rwdis, which has a different sinus structure. Glossispira is monotypic; living or fossil congeners are as yet unknown. (Crassiclava) McLean, subgen. nov. (of Crassispira Swainson, 1840) Type Species: Pleurotoma turricula Sowerby, 1834 (Syn- onyms: P. corrugata Sowerby, 1834; P. sowerbyi Reeve, 1843). Diagnosis: Shell relatively large, high spired, aperture elongate, subsutural cord weakly noded, shoulder concave below; periostracum thin, dark colored, color yellowish brown beneath, darker along the axial ribs. Protoconch whorls 24, smooth, rounded, axial sculpture of strong, narrow ribs arising at the periphery and extending across the base; spiral sculpture of fine cording, increasing in strength toward the pillar, slightly nodulous on crossing the axial ribbing. Sinus broad at the entrance, deep, U-shaped, bordered on the inside by a massive pad of parietal callus. Lip edge thin, crenulated by the spiral sculpture, stromboid notch relatively shallow, lip pre- ceded by a thickened axial rib % turn back. Anterior canal broad, deeply notched, inner lip raised. Operculum leaf shaped, nucleus terminal. Radula with a unicuspid rachidian tooth on a broad rectangular base, marginal teeth of modified wishbone or duplex type (Figures 48 to #9). Discussion: Crassiclava is unique in the subfamily in having a well formed rachidian tooth. The sinus is unlike that of other subgenera of Crassispira in having a strong parietal tubercle bordering the broad sinus entrance. Yet on all other shell characters the group seems closely related to other subgenera of Crassispira such as Crassispira, s.s., Crassispirella, Burchia, and Gibbaspira. In addition to the type species, Crassispira cortezi Shasky & Campbell, 1964, is referred. It differs in having a narrower sinus, weaker spiral sculpture, and attains a smaller size, but otherwise strikingly resembles the type species. The radula (Figure 48) is similar. Page 122 (Gibbaspira) McLean, subgen. nov. (of Crassispira Swainson, 1840) Type Species: Plewrotoma rudis Sowerby, 1834 (Syno- nym: Drillia albovallosa Carpenter, 1857). Diagnosis: Shell relatively large, the subsutural cord swollen and bluntly noded, shoulder concave below; ground color dark, periostracum thin. Protoconch of 2 smooth, dark whorls, followed by a whorl with slanted THE VELIGER Vol. 14; No. 1 axial ribs. Mature sculpture of minute spiral striae throughout, base with strong axial and spiral sculpture, noded at intersections; axial sculpture terminating above in white-tipped nodes at the periphery. Sinus deep, en- trance narrow, bordered by prominent callus tubercles on the parietal wall and outer lip. Lip edge not thickened, preceded by a massive thickened axial rib ¥ turn back, stromboid notch only weakly indicated. Anterior canal short, deeply notched, inner lip callus raised. The suture descends on the final whorl and then rises on the final Plate Explanation Subfamily Crassispirinae (continued) Figure 72: 1 Hindsiclava militaris (Reeve, 1843). LACM 65-16, Banderas Bay, Nayarit, Mexico, 10 to 15 fathoms. Figure 73: ! Doxospira hertleini Shasky, 1971. AHF 941-39, Gulf of Dulce, Costa Rica, 19 to 48 fathoms. Figure 74: Buchema granulosa (Sowerby, 1834). AHF 209-34, Santa Elena Bay, Ecuador, 8 to 10 fathoms. Figure 75: Lioglyphostoma ericea (Hinds, 1843). AHF 1055-40, Angel de La Guarda Island, Gulf of California, 57 fathoms. Figure 76: Lioglyphostoma rectilabrum McLean & Poorman, 1971. Holotype, LACM 1512, Guaymas, Sonora, Mexico, 40 to 125 fath- oms (ANSP, slide). Figure 77: Maesiella hermanita (Pilsbry « Lowe, 1932). LACM 65- 16, Banderas Bay, Nayarit, Mexico (ANSP, shell and slide). Figure 78: ' Maesiella maesae McLean & Poorman, 1971. Para- type, LACM 1514, Guaymas, Sonora, Mexico (ANSP, slide). Figure 79: Miraclathurella bicanalifera (Sowerby, 1834). LACM, Guaymas, Sonora, Mexico, 20 to 40 fathoms. Figure 80: Miraclathurella mendozana Shasky, 1971. LACM, Gulf of Tehuantepec, Chiapas, Mexico, 40 fathoms. Figure 81: Carinodrillia adonis Pilsbry « Lowe, 1932. AHF 1733- 49, Cabo Pulmo, Baja California, 18 to 21 fathoms. Figure 82: Carinodrillia dichroa Pilsbry « Lowe, 1932. LACM 68- 27, Guaymas, Sonora, Mexico, 30 to 60 feet. Figure 83: ? Carinodrillia halis (Dall, 1919). LACM 66-22, Muer- tos Bay, Baja California, 10 to 20 fathoms. Figure 84: Carinodrillia hexagona (Sowerby, 1834). LACM 65-17, La Cruz, Banderas Bay, Nayarit, Mexico, 12 feet. Figure 85: Carinodrillia lachrymosa McLean « Poorman 1971. Par- atype, LACM 1516, Cuastecomate Bay, Jalisco, Mexico, 15 to 65 feet (ANSP, slide). Subfamily Strictispirinae Figure 86: ! Strictispira ericana (Hertlein « Strong, 1951). LACM 66-22, Muertos Bay, Baja California, 10 to 20 fathoms. Figure 87: Strictispira stillmani Shasky, 1971. Paratype, LACM 70-15, Venado Island, Panama Canal Zone. Figure 88: + Cleospira ochsneri (Hertlein « Strong, 1949). AHF 167-34, Santa Maria Island, Galapagos Islands, 15 fathoms. Subfamily Zonulispirinae Figure 89: Zonulispira chrysochildosa Shasky, 1971. Paratype, LA CM 70-15, Venado Island, Panama Canal Zone. Figure 90: Zonulispira grandimaculata (C.B. Adams, 1852). LA CM 70-15, Venado Island, Panama Canal Zone. Figure 91: Compsodrillia albonodosa (Carpenter, 1857). LACM, San Felipe, Baja California. Figure 92: Compsodrillia alcestis (Dall, 1919). AHF 1087-40, En- senada de San Francisco, Sonora, Mexico, 15 to 18 fathoms. Figure 93: Compsodrillia bicarinata (Shasky, 1961). LACM 60-6, Espiritu Santo Island, Gulf of California, 40 to 90 fathoms. Figure 94: Compsodrillia excentrica (Sowerby, 1834). LACM 70- 15, Venado Island, Panama Canal Zone. Figure 95: Compsodrillia gracilis McLean & Poorman, 1971. Para- type, LACM 1518, Isla Santa Cruz, Galapagos Islands, 55 to 110 fathoms. Figure 96: Compsodrillia haliplexa (Dall, 1919). AHF 963-39, White Friars, Guerrero, Mexico, 20 to 25 fathoms. Figure 97: Compsodrillia jaculum (Pilsbry « Lowe, 1932). AHF 763-38, Cabo Corrientes, Jalisco, Mexico, 5 to 10 fathoms. Figure 98: Compsodrillia olssoni McLean & Poorman, 1971. Para- type, AHF 209-34, Santa Elena Bay, Ecuador, 8 to 10 fathoms. Figure 99: Compsodrillia opaca McLean & Poorman, 1971. AHF 1253-41, 8 miles west of Cedros Island, Baja California, 64 to 65 fathoms. Figure 100: Compsodrillia thestia (Dall, 1919). LACM, Puerto- citos, Baja California. Figure 101: Compsodrillia undatichorda McLean & Poorman, 1971. LACM, Isabela Island, Galapagos Islands, 41 to 55 fathoms (DeRoy Collection, shell). Figure 102: Pilsbryspira (Pilsbryspira) albinodata (Reeve, 1843). LACM, 70-15, Venado Island, Panama Canal Zone. Figure 103: Pilsbryspira (Pilsbryspira) aterrima (Sowerby, 1834). LACM, 70-15, Venado Island, Panama Canal Zone. Figure 104: Pilsbryspira (Pilsbryspira) aureonodosa (Pilsbry « Lowe, 1932). LACM, 70-15, Venado Island, Panama Canal Zone. Figure 105: Pilsbryspira (Pilsbryspira) collaris (Sowerby, 1834). LA CM, 70-15, Venado Island, Panama Canal Zone. Figure 106: Pilsbryspira (Pilsbryspira) garciacubasi Shasky, 1971 LACM 69-13, Banderas Bay, Nayarit, Mexico. Figure 107: Pilsbryspira (Nymphispira) bacchia (Dall, 1919). LA CM 68-27, Guaymas, Sonora, Mexico, 30 to 60 feet. Figure 108: ! Pilsbryspira (Nymphispira) nymphia (Pilsbry « Lowe, 1932). LACM 67-17, Libertad, Sonora, Mexico. [McLean] Figures 72 to 108 Tue Veticrr, Vol. 14, No. 1 a Vik * N - ASN : NS VQ. 2 SSAA ss SesSSSS SS 4 re, , 2 Shea LY : SSS : Sa ; SF GENS Li 2A SVE OW ‘ Wie a 5 RS a — — A = ge a\ > = a Sal 2 A ZA — NS * ie S L, SS ¢ ef Vol. 14; No. 1 ¥ whorl, producing a lateral twist to the shell. Operculum leaf shaped, nucleus terminal. Radula of the duplex type (Figure 57). Discussion: Gibbaspira is the only subgenus of Crassv- spira with a marked twist to the mature aperture and two prominent tubercles bordering the sinus. In addition to the type species, which ranges from Ma- zatlan, Mexico, to Ecuador, the subgenus is represented in the Caribbean by Crassispira dysoni (Reeve, 1846) which is particularly common on the Caribbean coast of Panama. It has a brown rather than the gray ground color of C. rudis, with more numerous and finer tubercles across the base. The name is taken from a manuscript label of Bartsch in the National Museum, derived from Latin, gibber— hunch-backed. Doxospira McLean, gen. nov. Type Species: Doxospira hertleini Shasky, 1971 (de- scribed elsewhere in this issue of The Veliger). Diagnosis: Shell relatively large, fusiform, with high spire and moderately elongate anterior canal; shoulder concave and smooth, lacking a subsutural cord except for a trace on the early whorls. Protoconch of 4 smooth whorls with deeply impressed sutures, gradually changing to mature sculpture. Axial sculpture of massive rounded ribs, crossed by numerous fine spiral cords. Sinus broad and deep, U-shaped, bordered within by a large parietal cal- losity extending forward into a spur, as in Hindsiclava. Lip not greatly thickened, not preceded by a massive axial rib; stromboid notch shallow. Operculum leaf shaped, nucleus terminal. Radula of the duplex type (Figure 73). Discussion: Doxospira is monotypic. In profile it resem- bles a number of other fusiform genera in different sub- families. It resembles Hindsiclava in sinus structure, duplex radula, and lack of a thickened rib on the back of the last whorl, but does not have the flat sided whorls and reticulate sculpture of that genus. It recalls Carino- drillia adonis but has a different radula (compare Figures 73 and 81). It also resembles the zonulispirine genera Compsodrillia and Ptychobela, differing in sinus structure and radula. Maesiella McLean, gen. nov. Type Species: Maesiella maesae McLean & Poorman, 1971 (described elsewhere in this issue of The Veliger). THE VELIGER Page 123 Diagnosis: Shell small to medium sized, whorls rounded, shoulder not deeply concave, subsutural cord a narrow raised thread. First 2 nuclear whorls smooth, rounded; strong diagonal axial ribs arise on the third nuclear whorl, persist for 4% turn and abruptly cease, replaced by weaker vertical ribs and spiral cords. Mature sculpture of sinuous axial ribs (obsolete on final whorl in some species), crossed by spiral cords and microscopic spiral striae. Sinus deep, the opening nearly obstructed by downward growth of the lip between the sinus and body whorl. Lip thick- ened by a massive varix, stromboid notch shallow, aper- ture elongate but not drawn into an anterior canal. Oper- culum with terminal nucleus. Radula of duplex type (Figures 77 to 78). Discussion: In addition to the type species the other mem- bers of the genus are Maesiella hermanita (Pilsbry & Lowe, 1932) and M. punctatostriata (Carpenter, 1865). Maesiella is related to Lioglyphostoma and Miracla- thurella, genera characterized chiefly by the greatly thick- ened final lip varix. Maesiella shares with Lioglyphostoma a tendency toward obstruction of the sinus resulting from a downward growth of the lip, a trait not shown in Mira- clathurella. Maesiella differs from Lioglyphostoma in having strong axial ribbing between the protoconch and the mature sculpture, a shorter anterior canal, more lat- erally directed sinus, more prominent stromboid notch, and lacking the thin leading edge of the lip. The species of Maesiella are characteristic of gravel bot- toms near rock, while those of Lioglyphostoma and Mira- clathurella are characteristic of soft, offshore bottoms. SHuTO (1969: 202-209) placed some Neogene species from the Philippines in the genus Euclathurella Wood- ring, 1928, using subgenera Miraclathurella Woodring, 1928, Thelecythara Woodring, 1928, Euclathurella, s.s., and Thelecytharella Shuto, 1969. None of the species dis- cussed by Shuto meet the criteria of the Woodring genera as used by McLean (n KEEN, 1971). Thelecytharella has the appearance of a crassispirine genus related to Maesi- ella, but having a broadly open rather than constricted sinus. Maesiella is dedicated to Virginia Maes, who first exam- ined the radula of two of the species. Subfamily STRICTISPIRINAE McLean, subfam. nov. (Figures 86 to 88) Diagnosis: Dark colored shells of moderate size, sculpture both axial and spiral, shoulder concave, with a well marked subsutural cord. Sinus deep, laterally directed; parietal callus well developed. Operculum leaf shaped, Page 124 nucleus terminal. Radular ribbon relatively large, rows of teeth numerous; marginal teeth only, solid and massive, lacking a smaller limb, elbow shaped, with a projecting collarlike flange on the inner side. Discussion: Two new genera with a distinctive and hith- erto unrecorded radular pattern are here grouped as a subfamily. The collarlike flange on the inner side of the marginal tooth is unique. The radula most resembles that of the Pseudomelatominae, although the rachidian of that group is lacking. The collarlike structure could be inter- THE VELIGER Vol. 14; No. 1 preted as a thickening at the point of contact of adjacent teeth. On the basis of shell characters, however, affinity to the Crassispirinae is suggested, particularly in the surface tex- ture and presence of well developed parietal callus about the sinus. Study of the anatomy and functional morphology should eventually reveal the true affinity of this group. I am much indebted to Virginia Maes for an exchange of ideas concerning the group, of which she has for some time been aware. Plate Explanation Subfamily Borsoniinae Figure 109: Borsoneila (Borsonella) bartschi (Arnold, 1903). AHF 981-39, Santa Barbara Island, California, 76 to 78 fathoms. Figure 110: Borsonella (Borsonella) galapagana McLean & Poor- man, 1971. Paratype, LACM 1526, Isla Santa Cruz, Galapagos Islands, 93 to 110 fathoms (ANSP, slide). Figure 111: Borsonella (Borsonellopsis) callicesta (Dall, 1902). Holotype, USNM 109030, off Acapulco, Guerrero, Mexico, 660 fms. Figure 112: ™Borsonella (Borsonellopsis) erosina (Dall, 1908). Holotype, USNM 123106, Gulf of Panama, 1672 fathoms. Figure 113: Cruziturricula arcuata (Reeve, 1843). AHF 448-35, Secas Islands, Panama, 12 fathoms. Figure 114: Suavodrillia willetti Dall, 1919. LACM 66-66, Graham Island, Queen Charlotte Islands, British Columbia, 30 fathoms. Figure 1/5: ?Suavodrillia kennicotti (Dall, 1871). Holotype, US NM 206201, Unga Island, Aleutian Islands, Alaska, 6 fathoms. Figure 116: ? Ophiodermella ophioderma (Dall, 1908). AHF 1165- 40, San Pedro, California, 14 fathoms. Subfamily Mitrolumninae Figure 117: ! Mitromorpha carpenteri Glibert, 1954. USNM 153445, San Pedro, California. Subfamily Clathurellinae Figure 118: Clathurella rigida (Hinds, 1843). LACM 66-15, Ran- cho E] Tule, Baja California. Figure 119: 1 Nanodiella nana (Dall, 1919). USNM 211485, off La Paz, Baja California. Figure 120: Glyphostoma (Glyphostoma) pustulosa McLean « Poorman, 1971. LACM, Santiago Island, Galapagos Islands, 17 fathoms. Figure 121: 1 Glyphostoma(Euglyphostoma) candida (Hinds, 1843). AHF 941-39, Gulf of Dulce, Costa Rica, 19 to 49 fathoms. Figure 122: Glyphostoma (Euglyphostoma) immaculata (Dall, 1908). Holotype, USNM 123115, Gulf of Panama, 153 fathoms. Figure 123: } Strombinoturris crockeri Hertlein & Strong, 1951. AHF 948-39, Bahia Honda, Panama, 30 to 35 fathoms. Figure 124: ? Crockerella crystallina (Gabb, 1865). USNM 109302, Catalina Island, California, 50 fathoms. Subfamily Mangeliinae Figure 125: Glyptaesopus oldroydi (Arnold, 1903). USNM 110611, Ballenas Bay, Baja California. Figure 126: Kurtziella (Kurtziella) plumbea (Hinds, 1843). USNM 206548, Monterey Bay, California, 13 fathoms. Figure 127: Kurtziella (Kurtzina) cyrene (Dall, 1919). USNM 331706, off Baja California (USFC sta. 2828), 10 fathoms. Figure 128: 7 Kurtzia arteaga (Dall & Bartsch, 1910). USNM 211 605, Barclay Sound, Vancouver Island, British Columbia, 8-34 fms. Figure 129: Pyrgocythara danae (Dall, 1919). USNM 266350, Agua Verde Bay, Baja California. Figure 130: “Clathromangelia” fuscoligata (Dall, 1871). USNM 56213, San Diego, California. Figure 131: “Clathromangelia’” nitens (Carpenter, 1864). USNM 334446, San Pedro, California. Figure 132: Euclathurella acclivicallis McLean & Poorman, 1971. LACM, Isla Santa Cruz, Galapagos Islands, 82 fathoms. Figure 133: ? Bellacythara bella (Hinds. 1843). AHF 770-38, San Jose Point, Guatemala, 7 to 11 fathoms. Figure 134: Tenaturris verdensis (Dall, 1919). LACM 66-19, El Pulmo, Baja California, 5 to 20 feet. Figure 135: Tenaturris janira (Dall, 1919). USNM 127534a, San Diego, California. Subfamily Daphnellinae Figure 136: Daphnella bartschi Dall, 1919. USNM 267341, “Baja California.” Figure 137: Rimosodaphnella deroyae McLean & Poorman, 1971. Paratype, LACM 1544. Figure 138: Xanthodaphne agonia (Dall, 1890). USNM 123136, Cocos Island, Costa Rica, 1010 fathoms. Figure 139: Xanthodaphne argeta (Dall, 1890). Holotype, USNM 96552, Galapagos Islands, 812 fathoms. Figure 140: Xanthodaphne egregia (Dall, 1908). Holotype, USNM 110610, off Peru, 2222 fathoms. Figure 141: Xanthodaphne imparella (Dall, 1908). Holotype, US NM 123114, Gulf of Panama, 1270 fathoms. Figure 142: Pleurotomella orariana (Dall, 1908). Holotype, USNM 123117, Gulf of Panama, 1270 fathoms. THE VELIGER, Vol. 14, No. 1 [McLean] Figures 109 to 142 ‘ - WEP? 126° °127 Vol. 14; No. 1 Strictispira McLean, gen. nov. Type Species: Crassispira ericana Hertlein & Strong, OBI Diagnosis: Shell medium sized, uniformly dark brown or black, subsutural cord prominent, midway on the concave shoulder slope. Protoconch of 2% smooth, rounded whorls. Sculpture of narrow axial ribs crossed by spiral cording that increases in strength toward the base. Sinus deep, laterally directed, parietal callus of mature speci- mens projecting down to nearly seal the entrance to the sinus. Lip edge not greatly thickened, stromboid notch shallow, lip preceded by a thickened rib 4% turn back, an- terior canal short, not deeply notched. Operculum leaf shaped, nucleus terminal. Radula of the elbow type, mar- ginal teeth only, with an inner flange, outer profile with a 90° curve close to the base of the tooth (Figures 86 to 87). Discussion: The shell differs from that of subgenera of Crassispiva in having a deep, laterally directed sinus, the parietal callus curved and projecting down to nearly seal the entrance. The type species, Strictispiva ericana, occurs offshore from the head of the Gulf of California to Santa Elena Bay, Ecuador, and attains a length of 22 mm. Additional members of the genus are S. stillmani Shasky, 1971, a shorter, more robust species characterized by a blue-gray periostracum, and the Caribbean S. ebenina (Dall, 1890). Two of the “Crassispira” species described by WoopriNnG (1928: 150; plt. 4, figures 9-10) from the Jamaican Mio- cene, C. ponida and C. lomata, are probable members of the genus, since they appear to have the characteristic sinus structure. Cleospiva McLean, gen. nov. Type Species: Monilispira ochsneri Hertlein & Strong, 1949 (Synonym: Pleurotoma bicolor Sowerby, 1834, not Risso, 1826). Diagnosis: Shell medium sized, dark colored with a yel- low peripheral band; shoulder concave, with a prominent subsutural cord and fine spiral striae. Protoconch of 2 smooth, rounded whorls. Axial ribs numerous on early whorls, rising to a strong peripheral angulation, crossed by broad spiral cords separated by deep grooves across the base; spiral cords crenulate the lip. Sinus deep, laterally directed, parietal callus downward projecting but not ob- structing the sinus entrance. Lip edge not greatly thick- ened, stromboid notch moderately deep, lip preceded by a slightly thickened axial rib; anterior canal short, not THE VELIGER Page 125 deeply notched. Operculum leaf shaped, nucleus termi- nal. Radula of marginal teeth only, of the elbow type with an inner flange, the outer profile with a curve amounting to about 45° (Figure 88). Discussion: Cleospira is represented only by the type spe- cies, which is not uncommon in shallow water at the Galapagos Islands. On radular characters, the affinity of Cleospira is with Strictispira, but on shell characters the resemblance is with the zonulispirine genus Pilsbryspira. Unlike most of the zonulispirine species, the axial ribs of Cleospira tend to be numerous and flat sided on the early whorls, in this respect resembling the pseudomelatomine genus Tvari- turris and the turriculine genus Pyrgospira. Subfamily ZONULISPIRINAE McLean, subfam. nov. (Figures 89 to 108) Diagnosis: Medium to large sized shells having a narrow, projecting subsutural cord, sculptured with axial ribs and spiral cords, the spiral sculpture usually more strongly developed than the axial sculpture across the base; mature lip preceded by a thickened rib. Protoconch initially smooth whorled or subcarinate, often followed by a whorl of narrow axial riblets. Sinus bordered by well developed parietal callus. Operculum leaf shaped, nucleus terminal. Basal membrane of radula relatively strong, marginal teeth only, hollow, not cylindrical, somewhat inflated away from the tip, some barbed at the tip, others un- barbed, base swollen, recurved. Discussion: This group differs from other toxoglossate subfamilies in having a relatively strong basal membrane of the radula and in having a fully developed operculum. As in Crassispira, the mature lip is preceded by a thick- ened axial rib, but the zonulispirine genera may usually be recognized in having a more laterally directed sinus and in having spiral sculpture more prominent than axial sculpture across the base. PowELL (1966) placed the genera grouped here in the Clavinae, on the basis of shell characters. The genus Zonulispira Bartsch, 1950, lacks axial ribbing on the early whorls. Compsodrillia Woodring, 1928, has strong axial ribbing on early whorls and is used for fusi- form species previously assigned to Carinodrillia, the type species of which proved to be crassispirine. Pilsbryspira Bartsch, 1950, although described originally as a subgenus of Crassispira, is used for the brightly colored “Crassi- spira” species assigned by previous authors to Monilispira, another group proving to be crassispirine. The type spe- cies of Pilsbryspira is P. pilsbryi Bartsch, 1950, thought to Page 126 have been from the eastern Pacific, but proving to be a synonym of the common Caribbean species P. alboma- culata (Orbigny, 1842). The species of Zonulispira, Comp- sodrillia, and Pilsbryspira, s.s., have a similarly shaped sinus that is laterally directed and somewhat constricted by parietal callus. The new subgenus Nymphispira differs in sinus structure from Pilsbryspzra, s.s. Radulae of most of the eastern Pacific species in the sub- family are illustrated in Figures 89 to 108. No generic dif- ferences are apparent. Some species in each group ap- parently lack barbs, while others clearly show a single barb. Examination under high power is necessary to de- tect the barb. The illustrated slides considered to show barbed teeth are those of Zonulispira chrysochildosa, Compsodrillia alcestis, C. bicarinata, C. excentrica, C. olssoni, C. undatichorda, Pilsbryspira aureonodosa, and P. collaris. Lacking barbs are those of Zonulispira grandi- maculata, Compsodrillia albonodosa, C. gracilis, C. hali- plexa, C. jaculum, C. opaca, C. thestia, Pilsbryspira al- binodata, P. aterrima, P. garciacubasi, P. bacchia, and P. nymphia. Additional radulae of each species should be examined before a species is definitely characterized as to the possession of a barbed tooth. (Nymphispira) McLean, subgen. nov. (of Pilsbryspira Bartsch, 1950) Type Species: Crassispira nymphia Pilsbry & Lowe, 1932. Diagnosis: Shell medium sized, dark colored with nodes or tubercles of yellow or orange; shoulder concave, sub- sutural cord moderately strong, smooth or noded; shoulder finely striate. Protoconch of 2 smooth, dark whorls, fol- lowed by ¥% whorl with axial ribbing. Mature sculpture of moderately strong axial ribs terminating in nodes at the periphery, crossed by nodular spiral cords on the base. Sinus deep, laterally directed, bordered on the inside by a pad of parietal callus and an open slot directed toward the suture. Lip not greatly thickened, stromboid notch relatively shallow; lip preceded by a slightly thickened axial rib; anterior canal short, not deeply notched. Oper- culum leaf shaped, nucleus terminal. Radula of hollow marginals, with recurved base, lacking barbs (Figures 107 to 108). Discussion: (Nymphispira) differs from Pilsbryspira, s.s., in having a sinus with an open slot leading toward the suture, tending also to have more pronounced develop- ment of the axial ribbing across the base. Two additional species are assignable: Pilsbryspira arsinoe (Dall, 1919) and P. bacchia (Dall, 1919), both of which differ from the type species in exhibiting stronger development of the parietal callus and having a heavier THE VELIGER Vol. 14; No. 1 rib back of the lip. Pilsbryspira nymphia is seldom found with a mature lip, but is the abundant member of the group and is therefore designated the type species. Pilsbryspira bacchia and P. nymphia lack barbs on the marginal teeth, but this may not be significant, since some species of Pilsbryspzra, s.s., also lack barbs. Subfamily Borsonunae Bellardi, 1875 (Figures 109 to 116) Diagnosis: Medium to large sized shells, fusiform in out- line, anterior canal moderately long, slightly twisted to the left; lip thin, arcuate, stromboid notch lacking. Colu- mella smooth or with | to 3 plicae. Sinus occupying the shoulder slope, broad, U-shaped, not bordered by heavy parietal callus. Operculum lacking, vestigial, or fully de- veloped. Basal membrane of radula weak, marginal teeth hollow, expanded basally, straight or slightly curved, minutely barbed or smooth at the tip. Discussion: PoweELL’s (1966) concept of the group in- cluded only genera having some indication of columellar plicae, for the most part inoperculate, and having a radula as defined above. The concept of the group is here en- larged to include genera lacking columellar plicae and often having fully formed opercula. The degree of de- velopment of the columellar plicae varies within genera and there are genera exhibiting partially developed or vestigial opercula. The subfamily is here envisioned as including fusiform shells having a broad shoulder sinus, lacking strong parietal callus, and having toxoglossate dentition. Borsonella Dall, 1908, is strongly plicate and typically inoperculate; marginal teeth lack barbs, although there is an angular projection near the tip (Figures 109 to 110). The new subgenus Borsonellopsis is weakly plicate and has a vestigial operculum; the teeth lack barbs (Figures 111 to 112). The fully operculate Cruziturricula Marks, 1951, represented by the single Recent species C. arcuata (Reeve, 1843), has a tooth with a small barb near the tip and another lower on the shaft (Figure 113). Two op- erculate genera that lack columellar plicae occur in the northeastern Pacific, Ophiodermella Bartsch, 1944, and Suavodrillia Dall, 1918, the radulae of which (Figures 114 to 116) are long and slender, lacking barbs. (Borsonellopsis) McLean, subgen. nov. (of Borsonella Dall, 1908) Type Species: Leucosyrinx erosina Dall, 1908. Vol. 14; No. 1 Diagnosis: Shell moderately large and high spired, aper- ture plus canal about % the length of the shell; shell yellowish under an adherent olivaceous periostracum. Whorls angulate, with a flat or concave shoulder, immedi- ate subsutural area faintly swollen. Sculpture of spiral cords and axial ribs, obsolete in some species, but nodular upon the angulate periphery. Sinus on the shoulder slope, broad, U-shaped, parietal callus lacking. Lip arcuate, stromboid notch lacking, anterior canal short, broadly open, twisted to the left; columella faintly plicate or smooth, columellar area broad, not raised above the pillar. Operculum small, rounded, with apical nucleus. Radula of hollow marignal teeth only, base expanded, shaft rela- tively short, lacking barbs (Figures 111 to 112). Discussion: Borsonellopsis differs from Borsonella in at- taining a larger size, having weaker columellar plicae, and possessing a small operculum, at least in the type spe- cies. None of the available specimens have complete protoconchs. Three eastern Pacific species occur at depths of several hundred fathoms to abyssal depths: Borsonella erosina (Dall, 1908); Borsonella callicesta (Dall, 1902); and Bor- sonella diegensis (Dall, 1908). Numerous taxa described by Dall in various genera are tentatively regarded as synonyms of the latter two species, pending further study. The name is taken from a manuscript label of Bartsch in the collection of the U. S. National Museum. Subfamily MirRoLuMNINAE Sacco, 1904 (Figure 117) Diagnosis: Relatively small shells, anterior end usually truncate, axial and spiral sculpture of nearly equal strength; columella with folds or plicae that may be pro- nounced or faint. Protoconch paucispiral, two whorled, tip usually inrolled. Sinus either not apparent or consist- ing of a shallow indentation next to the suture. Operculum wanting. Basal ribbon of radula weak, marginal teeth hol- low, expanded at the base, lacking barbs, slightly con- stricted below the tip. Discussion: Powetr. (1966) segregated the genera here grouped and several others as the “mitromorphid gen- era, in the subfamily Borsoniinae. They differ from Bor- soniinae in lacking a deep U-shaped sinus; they are usually smaller, the sculpture tending to be clathrate, and they are characteristic of shallower water. These differences are afforded subfamily recognition. The subfamily name Mitrolumninae Sacco, 1904, is utilized. Diptychomitrinae Bellardi, 1889, is rejected, since Diptychomitra Bellardi, 1889, is regarded as a syno- THE VELIGER Page 127 nym of Mitrolumna and the name has not come into gen- eral use. The typical genus and several others in the group have frequently been regarded as mitrid because of the char- acteristic columellar plicae and lack of a defined sinus (see CERNOHORSKY 1970: 63-64). Genera represented in the eastern Pacific are Mitro- lumna Bucquoy, Dautzenberg & Dollfus, 1883 (Synonym: Arielia Shasky, 1961); Mitromorpha Carpenter, 1865; Cymakra Gardner, 1937; and Diptychophlia Berry, 1964. Previous authors have used Mitromorpha for species better placed in Cymakra. Mitromorpha has a narrow aperture, lacks columellar plicae, and has spiral sculpture only. Cymakra differs in having an oval aperture, columel- lar plicae, and both axial and spiral sculpture. The toxoglossate teeth of Mitromorpha carpenteri are illustrated (Figure 117). EMERSON & RaDWwIN (1969) fig- ured the radula of their species Mztrolumna keenae. Subfamily CLATHURELLINAE McLean, subfam. nov. (Figures 118 to 124) Diagnosis: Small to moderately large shells lacking a sub- sutural fold, sculpture both axial and spiral. Protoconch usually small tipped, developing a pronounced medial carination, or paucispiral with rounded outline. Sinus broad and deep, encircled with heavy callus; anterior canal moderately elongate, deeply notched; inner and outer lips smooth or heavily denticulate. Operculum want- ing. Basal ribbon of radula weak, marginal teeth long and slender, slightly curved, unbarbed, base evenly swollen. Discussion: The clathurelline genera, traditionally placed in the Mangeliinae, are grouped here as a subfamily on the basis of shell and radular characters. Distinctive shell characters are the carinate protoconch of most members, the deep subtubular sinus, of a breadth and depth equiva- lent to that of the anterior canal, and the deep notch of the anterior canal. Mangeliine genera do not have deeply notched anterior canals. Species of some clathurelline genera such as Glyphostoma and Strombinoturris reach moderately large sizes, while mangeliine species are char- acteristically small. Clathurelline radular teeth are more akin to those of some borsoniine genera, being long and slender, with evenly swollen bases. Eastern Pacific genera having a marked carinate phase of the protoconch are Clathurella Carpenter, 1857; Nan- nodiella Dall, 1919; Glyphostoma Gabb, 1872 (and sub- genus Euglyphostoma Woodring, 1970); and Strombino- turris Hertlein & Strong, 1951. The southern Californian genus Crockerella Hertlein & Strong, 1951, differs in hav- ing a paucispiral protoconch. Page 128 Toxoglossate teeth of the clathurelline genera are illus- trated (Figures 118 to 124). Noteworthy are the relatively large teeth of Nannodiella nana (Figure 119) and the ser- rated edge near the tip of the tooth in Glyphostoma im- maculata (Figure 122). Subfamily MANGELIINAE Fischer, 1887 (Figures 124 to 135) Diagnosis: Small, slender shells; sinus shallow to moder- ately deep, outer lip usually with terminal varix; lip denti- culate in some genera; anterior canal relatively short, not deeply notched. Protoconch smooth or variously sculp- tured. Operculum wanting in warm water genera, present in some boreal genera. Basal ribbon of radula vestigial, marginal teeth hollow, relatively short, rarely barbed, base of tooth with an irregular swelling, some resembling par- tially rolled leaves with an upcurved spur at the base. Discussion: The subfamily concept of PowELL (1966) is employed, with the exception that the clathurelline genera are excluded. Form of the marginal tooth in the remaining genera still covers a broad range, but there are apparently no members with long, slender teeth having evenly swollen bases. Cytharinae of THIELE (1929) is a synonym, although Thiele’s concept included genera placed in the last 5 sub- families utilized here. Fourteen genera of Mangeliinae are recognized in the tropical eastern Pacific (see MCLEAN in KEEN, 1971), but the genera pertaining to cool water eastern Pacific species are tentative at this point. Radular characters are known for relatively few eastern Pacific genera and species. In Glyptaesopus oldroydi (Fig- ure 125), the base of the tooth is flat, as in Mitromorpha carpenter: (Figure 117). Species of Kurtziella, Kurtzia, Pyrgocythara, and “Clathromangelia” (Figures 126 to 131) have the “hilted dagger’ tooth described by Powell. Euclathurella acclivicallis (Figure 132) and Bellacythara bella (Figure 133) have angular bases to the teeth. In the genus Tenaturris (Figures 134 to 135) the shaft bears a prominent barb. Bellacythara McLean, gen. nov. Type Species: Clavatula bella Hinds, 1843. Diagnosis: Shell moderately large for the subfamily, slen- der and fusiform, with rounded whorls and an elongate canal. Protoconch with small tip, second whorl rounded, third whorl with a moderately strong, nodose carination, THE VELIGER Vol. 14; No. 1 gradually changing to the rounded axial ribbing of later whorls. Axial sculpture of low rounded ribs crossed by numerous fine cords. Sinus shallow, on the shoulder slope, lip with a sharply pointed tubercle below the sinus. Op- erculum wanting. Marginal tooth relatively short and broad, tapered to a sharp point, base swollen, V-shaped (Figure 133). Discussion: The sharp, pointed tubercle on the lip below the sinus and subcarinate phase of the protoconch are characteristic and not found in other mangeliine genera known to me. Acmaturris Woodring, 1928, is similar in size and sculpture. The two genera have a similar sinus structure; the sinus is broad and shallow, without parietal callus. Bellacythara bella is exceptionally large among eastern Pacific mangeliine species. It reaches a length of 15 mm and is thereby matched only by Tenaturris verden- sis (Dall, 1919). Subfamily DAPHNELLINAE Hedley, 1922 (Figures 136 to 142) Diagnosis: Small to moderately large shells, sculpture usually cancellate. Protoconch tall, with several rounded, frequently diagonally cancellate whorls, sometimes with axial ribbing or cancellate sculpture. Sinus sutural, shaped like a reversed-L, parietal callus present in some; lip pro- duced forward, edge thin or with terminal varix, lip den- ticulate in some, columella usually smooth. Operculum wanting. Basal membrane of radula vestigial, marginal teeth hollow, awl shaped, with cylindrically expanded bases, the tip usually constricted, resembling a candle flame. Discussion: The concept of Daphnellinae utilized here follows that of PowELt (1966). The sutural sinus is char- acteristic of all genera and most have a diagonally cancel- late protoconch, a feature not occurring in other sub- families. Some genera have axial or cancellate sculpture on the protoconch. Such a difference in the protoconch is considered by Powell as of sufficient importance to war- rant generic separation of groups otherwise having similar sculpture. Shallow water eastern Pacific genera with diagonally cancellate protoconchs are Daphnella Hinds, 1844; Rz- mosodaphnella Cossmann, 1915; Philbertia Monterosato, 1884; and the new genus Truncadaphne. Genera with axial ribbing on the protoconch are Kermia Oliver, 1915; Veprecula Melvill, 1917; and the new genus Microdaphne. Deep water genera are Xanthodaphne Powell, 1942; Pleurotomella Verrill, 1873; Phymorhynchus Dall, 1908; and Gymnobela Verrill, 1884. Vol. 14; No. 1 THE VELIGER Page 129 Table 1 CHARACTERS OF THE SUBFAMILIES OF THE TURRIDAE Radular teeth Earliest api- Columellar Parietal Position of Subfamily Central Lateral Marginal Operculum cal whorls folds callus sinus Pseudomelatominae Large None Solid Present Smooth None None Shoulder Clavinae Vestigial Broad, Solid Present Smooth or None Present Shoulder comblike carinate Turrinae Large, None Solid, Present Smooth None None Periphery vestigial, wishbone or absent Turriculinae Large, None Solid, Present Smooth None None Shoulder vestigial, wishbone or absent or duplex Crassispirinae Rarely None Solid, Present Smooth or None Present Shoulder present duplex weakly carinate Strictispirinae None None Solid Present Smooth None Present Shoulder Zonulispirinae None None Hollow, Present Smooth None Present Shoulder mostly barbed Borsoniinae None None Hollow, Either Smooth Either None Shoulder rarely present present barbed or absent or absent Mitrolumninae None None Hollow, None Smooth Present None Suture, no barbs shallow Clathurellinae None None Hollow, None Usually None Present Shoulder no barbs carinate Mangeliinae None None Hollow, None Smooth, sub- None Either Shoulder rarely carinate, or present barbed cancellate or absent Daphnellinae None None Hollow, None Usually None Either Suture no barbs diagonally present reticulate or absent Daphnelline radulae are illustrated in Figures 136 to Mego Truncadaphne McLean, gen. nov. Type Species: “Philbertia’ stone: Hertlein & Strong, 1939, Diagnosis: Shell small (to 4 mm in length), sturdy, sculp- tured with thick axial ribs, overridden by narrow spiral cords that are beaded at intersections; suture bordered by a narrow subsutural cord, shoulder concave below. Proto- conch darker than the rest of the shell, of 3 bulbous whorls, the first spirally lirate, the second and third diagonally reticulate. Sinus deep, subtubular, laterally directed, bor- dered on the inside by projecting parietal callus. Lip edge moderately thick, preceded by a stronger than normal axial rib; lip lirate within, corresponding to the spiral cording. Anterior canal truncate, twisted to the left, colu- mella smooth. Discussion: Truncadaphne resembles Pseudodaphnella Boettger, 1895, and Kermia Oliver, 1915, in having simi- lar clathrate sculpture and parietal callus bordering the sinus, but differs from both in having a diagonally cancel- late, rather than axially ribbed protoconch. Truncadaphne is monotypic. The type species was de- scribed as a Pleistocene fossil from San Salvador Island, Galapagos Islands. Recently dead specimens are reported here for the first time from Duncan and Isabela Islands, Galapagos Islands, 35-60 fathoms. Truncadaphne stonei was described originally as having a smooth nucleus and lacking lip denticles, omissions attributed to the poor preservation and immaturity of the type specimen. Microdaphne McLean, gen. nov. Type Species: Philbertia trichodes Dall, 1910 (=Pleuro- toma hirsutum DeFolin, 1867, not Bellardi, 1847). Diagnosis: Shell small (to 4 mm in length), thin, but strengthened by narrow, raised axial ribs and spiral cords Page 130 that are spinose at intersections. Protoconch of 4 relatively large, dark whorls, the first spirally lirate, the rest with slanting axial folds. Sinus sutural, deep, not bordered by parietal callus. Lip preceded by a massive final varix; lip infolded, obstructing the aperture to a narrow opening; lip strongly lirate within, corresponding to the external grooves. Anterior canal moderately elongate, pillar slanted to the left, columella smooth within. Operculum wanting. Discussion: Characteristic features of Microdaphne are small size, spinose sculpture, narrow aperture, and the axially ribbed protoconch. It is essentially unlike any other daphnelline genus. Raphitoma Bellardi, 1848, has spinose sculpture, but is larger, has a broader aperture, and an inrolled, spirally malleate protoconch. Micro- daphne may perhaps be closer to Veprecula Melvill, 1917, which has a similar protoconch, tendency toward spinose sculpture, and similarly twisted canal, but a broad aper- ture and unthickened lip. Microdaphne is monotypic. Microdaphne trichodes is common on offshore gravel bottoms from the Gulf of Cali- fornia to Colombia and the Galapagos Islands. It has also been illustrated by Mags (1967: plt. 16, fig. B, as ‘““Daph- nellinae sp.) from Cocos-Keeling Atoll in the Indian Ocean, suggesting that it is widely distributed in the Indo- Pacific. Literature Cited BERRY, SAMUEL STILLMAN 1968. Notices of new eastern Pacific Mollusca. - VII. Leaflets in Malacology 1 (25): 155 - 158 (26 Sept. 1968) CERNOHORSKY, WALTER OLIVER 1970. Systematics of the families Mitridae and Volutomitridae (Mollusca : Gastropoda) . Bull. Auckland. Inst. & Mus. no. 8: iv+190 pp.; 18 plts.; 222 text figs. (1 Oct. 1970) EMERSON, WILLIAM KeirH & ANTHONY D’ATTILIO 1969. Two new species of Galapagan turrid gastropods. The Veliger 12 (2): 149-156; plts. 28, 29; 5 text figs. (1 October 1969) Hasse, TADASHIGE & SADAO KoOSUGE 1966. New genera and species of the tropical and subtropical Pacific molluscs. Venus (Japan. Journ. Malacol.) 24 (4): 312 - 341; plt. 29 (May 1966) THE VELIGER Vol. 14; No. 1 KEEN, A. MyRA 1958. Sea shells of tropical West America; marine mollusks from Lower California to Colombia. i-xi + 624 pp.; illus. Stanford, Calif: (Stanford Univ. Press) (5 December 1958) 1971. Sea shells of tropical West America; marine mollusks from Baja California to Peru. Second ed.; in press. Stanford, Calif. (Stanford Univ. Press) Maes, VirGINIA ORR 1967. The littoral marine mollusks of Cocos-Keeling Islands (Indian Ocean). Proc. Acad. Nat. Sci. Philadelphia 119 (4): 93-217; plts. 1 - 26; 4 text figs. (6 Sept. 1967) 1971. Evolution of the toxoglossate radula and methods of envenomation. Ann. Rept. Amer. Malacol. Union for 1970: 69 - 72 (18 February 1971) McLean, James Hamitton & Leroy H. PoorMAN 1971. New species of tropical eastern Pacific Turridae. The Veliger 14 (1) 89-113; 2 plts. (1 July 1971) Morrison, JosEPpH Paut ELDRED 1966. On the families of Turridae. Malacol. Union for 1965: 1, 2 PowELL, ARTHUR WILLIAM BADEN 1942. The New Zealand Recent and fossil Mollusca of the family Turridae, with general notes on turrid nomenclature and systematics. Bull. Auckland Inst. & Mus., no. 2: 188 pp.; 14 plts.; text figs. (15 July 1942) 1964. | The family Turridae in the Indo-Pacific. Part 1. The subfamily Turrinae. Indo-Pacific Mollusca 1 (5): 227 to 346; plts. 172 - 262 (31 March 1964) 1966. The molluscan families Speightiidae and Turridae. Bull. Auckland Inst. & Mus., No. 5: 184 pp.; 23 plts. (2 November 1966) 1967. The family Turridae in the Indo-Pacific. Part la. The subfamily Turrinae concluded. Indo-Pacific Mollusca 1(7): 409-444; plts. 298 - 317 (15 May 1967) 1969. The family Turridae in the Indo-Pacific. Part 2. The subfamily Turriculinae. Indo-Pacific Mollusca 2 (10): 207 - 416; plts. 188 - 324 (9 September 1969) SHasky, Dona.p R. 1971. Ten new species of tropical eastern Pacific Turridae. The Veliger 14 (1): 67-72; 1 plt. (1 July 1971) SuuTo, Tsucio 1969. Neogene gastropods from Panay Island, the Philippines. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology 19 (1): 1-250; plts. 1-24; 43 text figs. (25 January 1969) THIELE, JOHANNES 1929[-1931]. Handbuch der systematischen Weichtierkunde. Jena, Gustav Fischer, 1929 - 1935; 1154 pp.; 893 text figs. (pp. 1-376 publ. in 1929) Wooprinc, WENDELL PHILLIPS 1928. Miocene mollusks from Bowden, Jamaica: Part II: Gastropods and discussion of results. Carnegie Inst. Washington, publ. no. 385. pp. i- vii+ 1-564; plts. 1-40; 3 text figs. (28 November 1928) Ann. Rept. Amer. Vol. 14; No. 1 THE VELIGER NOTES & NEWS Note on an Unusual Pacific Coast Cephalopod BY ALLYN G. SMITH California Academy of Sciences, Golden Gate Park San Francisco, California 94118 Tue DEPARTMENT OF INVERTEBRATE ZOOLocy, California Academy of Sciences, recently received 2 specimens of an unusual Pacific Coast octopod, Vampyroteuthis infernalis Chun, 1903, from Robert R. Talmadge of Eureka, Cali- fornia. Both were trawled by a commercial “drag boat,” the M/V Ina (Capt. Jim Riley), working out of Eureka. The first specimen was taken in 450 fathoms in Eel River Canyon off Eureka, April 1969, and is the larger of the two, requiring a gallon-capacity jar as a container. The second specimen was taken in 380 fathoms off Trinidad, Humboldt County, California, from the stomach of a black cod, August 1970, and is smaller. Both specimens are in such bad condition that no measurements are possible. Identification was confirmed by Dr. Takashi Okutani of the Tokai Regional Fisheries Research Labor- atory, Tokyo, Japan, who was a recent Academy visitor. The only published Pacific Coast record for this spe- cies is based on Cirroteuthis macrope Berry, 1911, from 2113-2259 fathoms, off Santa Catalina Island, California (2 specimens) ; U. S. Fish Commission Station 4393, col- lected 30 March 1904. Dr. Grace Pickrorp (1946) in a comprehensive report on Vampyroteuthis includes Berry’s species in the synonymy of V. infernalis, which has been listed under other names as well. Literature Cited Berry, SAMUEL STILLMAN 1911. Preliminary notices of some new Pacific cephalopods. Proc. U.S. Nat. Mus. 40(1838): 589-592 (31 May 1911) 1912. A review of the Cephalopoda of western North America. Bull. U.S. Bur. Fisheries 1 (XXX), Doc. 761: 267 - 336; plts. 32-56; text figs. 1-16 (24 July 1912) PickForp, Grace E. 1946. Vampyroteuthis infernalis Chun - an archaic dibranchi- ate cephalopod. 1. Natural history and distribution. Dana Report 29: 1-40 Carlsberg Foundation Page 131 Notice about a Revised Edition of SEASHELLS OF TROPICAL WEST AMERICA by A. MYRA KEEN Extended coverage has enlarged the revised edition of this book to almost twice the size of the first edition. The southern limit now takes in northwestern Peru and the offshore islands. Deep-water and microscopic mollusks are cited, as well as molluks without shells. The book thus is an attempt to list all of the described marine mol- lusks of the Panamic province (except for certain cephal- opods). Altogether over 3 300 species are listed, of which 2 430 are gastropods. Most of the forms larger than 5 mm in length are figured, and sample illustrations are given for the smaller forms. The largest family proves to be the Pyramidellidae, with 352 species. Second come the Turri- dae with 300; text and illustrations for these have been supplied by Dr. James McLean. Other portions of the text of the book have been contributed by several col- leagues. Not only has the number of pages in the revised edition doubled, to around 1 100, but the number of color plates increased from 10 to 22; so also has the estimated price, which is predicted to be around $25.00. Stanford Univer- sity Press is scheduling publication for late August. Your editor is pleased with the approaching publication of this book, the first edition of which has so stimulated research in the geographical area covered by it that the larger size of the new edition became necessary. And while some persons might think that the price is higher, in actuality it is really lower: double number of pages, more than double the number of color plates and, in spite ef the much higher costs of labor and paper, only double the original price. We foresee a further stimulation in the research activity in the somewhat expanded area as a direct consequence of this book’s effect. Book dealers are prepared to accept advance orders! RS First International Congress of Systematic and Evolutionary Biology The Society of Systematic Zoology and the Interna- tional Association for Plant Taxonomy have joined forces in sponsoring a major mid-term Congress of a botanical/ zoological interaction at the international level. Thus, the First International Congress of Systematic and Evolution- ary Biology will be held at the University of Colorado, Boulder, Colorado, in August of 1973. Page 132 Program plans at the present time encompass inter- disciplinary symposia and contributed papers sessions. The botanists will not convene a nomenclatural section, but a zoological one on this subject is expected. In the next few months the outline of the program and other activities will begin to take form. All suggestions will be gratefully received, carefully considered, and as many adopted as practical or feasible. Correspondence may be addressed to the Secretary of the Steering Committee, Dr. James L. Reveal, Department of Botany, University of Maryland, College Park, Maryland 20740, U.S.A. Important Notices REGARDING POSTAL SERVICE While increases in postal charges were anticipated, the actual amount involved could not be ascertained until 4 days before the effective date. Thus, we have been un- able to adjust our membership dues and subscription rates to cover these increases. Effective immediately, we must also raise our handling charges for backissues and other materials. Further, we will not acknowledge the receipt of manuscripts, unless an addressed envelope with the necessary postage is enclosed. We must call the attention of our Members and Sub- scribers to the fact that we mail our journal on the date stated on the cover of a particular issue. After we have delivered the journal to the Post Office, our control ends. Delays in delivery seem to become more and more com- mon. Needless to say that we regret this very much; we had hoped that when the salaries of the Postal Workers were increased, the service would improve. However, this seems not to be the case. If it is any consolation to our readers, we might mention that we have had some rather unpleasant experiences ourselves: an Air Mail Special Delivery letter to Los Angeles took 2 weeks! 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CALIFORNIA MALAcOzooLocicat Society, Inc. is a non-profit educational corporation (Articles of In- corporation No. 463389 were filed January 6, 1964 in the office of the Secretary of State). The Society publishes a scientific quarterly, the VELIGER. Donations to the Society are used to pay a part of the production costs and thus to keep the subscription rate at a minimum. Donors may designate the Fund to which their contribution is to be credited: Operating Fund (available for current production) ; Savings Fund (available only for specified purposes, such as publication of especially long and signi- ficant papers); Endowment Fund (the income from which is available. The principal is irrevocably dedicated to scientific and educational purposes). Unassigned dona- tions will be used according to greatest need. Contributions to the C. M.S., Inc. are deductible by donors as provided in section 170 of the Internal Revenue Code (for Federal income tax purposes). 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An issue of the journal will be designated as a Memorial Issue in honor of a person from whose estate the sum of $5000.- or more has been paid to the Veliger Endowment Fund. If the bequest is $25 000.- or more, an entire volume will be dedicated to the memory of the decedent. THE VELIGER Vol. 14; No. 1 At a Regular Membership Meeting of the CALIFORNIA MatacozootocicaL Society, Inc. the following policies were adopted by unanimous vote: Membership open to individuals only - no institutional or society memberships. Please send for membership ap- plication forms to the Manager or the Editor. Effective January 1, 1967 there will be an initiation fee of $2.- for persons joining the Society. Members receive The Veliger free of further charges and are entitled to purchase one copy of any supplement pub- lished during the current membership year at a special discount (to be determined for each supplement). Membership renewals are due on or before April 15 each year. 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That the printed date is the actual date of pub- lication under the rules of the International Commission on Zoological Nomenclature is based on the following facts: 1) The journal is delivered to the Post Office on the first day of each quarter, ready for dispatch; 2) at least three copies are mailed either as first class items or by air mail; 3) about 20 copies are delivered in person to the mail boxes or to the offices of members in the Berkeley area; 4) two copies are delivered to the re- ceiving department of the General Library of the Univer- sity of California in Berkeley. Thus our publication is available in the meaning of the Code of the ICZN. The printed publication date, therefore, may be relied upon for purposes of establishing priority of new taxa. Vol. 14; No. 1 BOOKS, PERIODICALS, PAMPHLETS The Systematics and Biology of Abyssal and Hadal Bivalvia by Jorcen Knupsen. Galathea Report vol. 11; pp. 1 to 241; plts. 1 to 20; 130 text figs. November 6, 1970. Danish Science Press, Copenhagen; 120 Danish kroner (about $17.50). This work, which is Dr. Knudsen’s doctoral thesis, is based not only on collections of the Galathea expedition but also the deep-sea material in several museums in Europe and the United States, which he visited. Numer- ous (over 40) new species are described; a new family, the Galatheavalvidae, is established with the genus Gala- theavalva as the type; this genus too, is new. Of the new species, 8 are in the Eastern Pacific; new records and range extensions bring the number of Eastern Pacific deep-water bivalves discussed to 16, not including deep- water Pholadacea he had previously recorded. There is a careful analysis of the abyssal bivalves, their ecology, distribution, variation, feeding, mode of reproduction, and adaptations to a specialized environment. Illustrations are of good quality photographs and camera lucida drawings of anatomy and shell features. Here, for the first time, is a reasonably complete sum- mary of the deep-sea bivalve fauna on a worldwide basis. Many species described from one ocean are now recog- nized as occurring much more widely. Dr. Knudsen has done an admirable job of working out synonymies, and his report should be of immense help to students faced with the task of identifying offshore material. It is prob- able that many more species remain to be described as the deepsea fauna becomes more available, but this work will stand as a compendium of what is on record up to the present. MK Faunas of the Pleistocene Champlain Sea by Frances J. Wacner. Geological Survey of Canada, Bulletin 181, pp. 1 - 104; plts. 1-7; 2 text figs.; 3 tables. 1970. The Champlain Sea was a shallow body of water of varying salinity which covered portions of eastern Canada from about 8000 to 11500 years ago. The present report deals with the invertebrate fossils left by the retreat of the sea. Water temperatures were boreal in the early stages but became more temperate in later stages. The THE VELIGER Page 135 paleoecology is discussed on pp. 3 to 15, systematics on pp. 16 to 48 (mollusks, pp. 28 to 45; plts. 2 to 5). Several species in the fauna currently live in northern Pacific waters. Included among these are such well-known species as Hiatella arctica (Linnaeus), Macoma balthica (Lin- naeus), Mya truncata Linnaeus, Mytilus edulis Linnaeus, Nucula tenuis Montagu, Serripes groenlandicus (Brugu- iére), Thyasira gouldi Philippi, Cylichna alba (Brown), Lunatia pallida Broderip & Sowerby, Trichotropis borealis (Broderip & Sowerby). LGH Coastal Brazilian Seashells by E. C. Rros. Museo Oceanografico de Rio Grande, Fundacao Cidade do Rio Grande. Pp. 1 to 255; 4 maps; 60 plts. November, 1970. This is a well illustrated check list that is as complete as the author, with unusual collecting facilities, can make it. Not only the nearshore but the offshore fauna is covered. For each species there is a figure, a statement of range, collecting records, habitat, and a note as to the original name combination and synonyms. Coverage in- cludes 860 species of mollusks, of which 544 are gastro- pods. There is a bibliography of 300 titles and an alpha- betical index to genera. Arrangement of the list is system- atic. The illustrations, mostly halftone photographs, come out well, and the book should be a very useful addition to any serious collector’s library. The price is not indicated but doubtless could be obtained from the Museo Oceano- grafico de Rio Grande, Caixa Postal 379, Rio Grande, Rio Grande do Sul, Brasil. A brief biographical note on the last page of the book indicates that the author’s full name is Dr. Eliézer de Carvalhos Rios. MK Molluscan Digest The International Publication for Malacological Research edited by Steven J. Long and Jack Brookshire. Vol. 1, nos. 1 to 4. Published on the first day of each month. 1971. $4.00 per year in U.S. A., Canada and Mexico; $5.00 all foreign and $6.00 to libraries, museums, institutions. This monthly publication offers a valuable service to all workers in the field of malacology as it lists all recent publications — at least, the editors are making a truly strenuous effort to make this list complete and as up-to- date as is possible. Information is also provided on re- searchers, their problems and their needs - for literature, specimens, information, etc. Page 136 THE VELIGER The editors will send a free sample copy to any inter- ested worker who provides an addressed large size (69 inches) envelope. In view of the increasing postal rates, this reviewer thinks it would be appropriate for those requesting a sample copy to provide postage. Requests may be sent to Mr. Steven J. Long, 110 Cuyama Avenue, Pismo Beach, CA 93449, U.S.A. RS of Sea and Shore published by of Sea and Shore Publications, Port Gamble, Washington. The first issue of volume 2 of this publication has just reached us. The front cover presents 3 views of Haliotis kamtschatkana in full color, while the back cover has a number of illustrations of shell jewelry in color. This quarterly publication no doubt fills a need of a large number of shell collectors. The subscription rate is cer- tainly modest ($3.50 per year). RS Vol. 14; No. 1 THE VELIGER is open to original papers pertaining to any problem concerned with mollusks. This is meant to make facilities available for publication of original articles from a wide field of endeavor. Papers dealing with anatomical, cytological, distri- butional, ecological, histological, morphological, physiological, taxonomic, etc., aspects of marine, freshwater or terrestrial mollusks from any region, will be considered. Even topics only indirectly concerned with mollusks may be acceptable. It is the editorial policy to preserve the individualistic writing style of the author; therefore any editorial changes in a manuscript will be submitted to the author for his approval, before going to press. Short articles containing descriptions of new species or other taxa will be given preferential treatment in the speed of publication provided that arrangements have been made by the author for depositing the holotype with a recognized public Museum. Museum numbers of the type specimens must be included in the manuscript. Type localities must be defined as accurately as possible, with geo- graphical longitudes and latitudes added. Short original papers, not exceeding 500 words, may be published in the column “NOTES and NEWS’; in this column will also appear notices of meetings of regional, national and international malacological organizations, such as A.M. U., U.M.E., W.S.M., etc., as well as news items which are deemed of interest to our Members and subscribers in general. Articles on “METHODS and TECH- NIQUES” will be considered for publication in another column, provided that the information is complete and techniques and methods are capable of duplication by anyone carefully following the description given. Such articles should be mainly original and deal with collecting, preparing, maintaining, studying, photographing, etc., of mollusks or other invertebrates. A third column, entitled “INFORMA- TION DESK,” will contain articles dealing with any problem pertaining to collecting, identifying, etc., in short, problems encountered by our readers. In contrast to other contributions, articles in this column do not necessarily contain new and original materials. Questions to the editor, which can be answered in this column, are invited. The column “BOOKS, PERIODICALS, and PAMPHLETS” will attempt to bring reviews of new publications to the attention of our readers. Also, new timely articles may be listed by title only, if this is deemed expedient. Manuscripts should be typed in final form on a high grade white paper, not exceeding 84” by 11”, at least double spaced and accompanied by a clear carbon or photo copy. A pamphlet with detailed suggestions for preparing manuscripts intended for publication in THE VELIGER is available to authors upon request. A self-addressed envelope, sufficiently large to accommodate the pamphlet (which measures 514” by 8'%”’), with double first class postage, should be sent with the request to the Editor. EDITORIAL BOARD Dr. Donatp P. Azzorrt, Professor of Biology Dr. Leo G. HERTLEIN, Hopkins Marine Station of Stanford University Curator of Invertebrate Paleontology, Emeritus Piet € Sci Riane Oh, (He Datorton, Phojanor a) Chetan California Academy of Sciences, San Francisco University of Pennsylvania, Philadelphia, and Dr. A. Myra KEEN, Professor of Paleontology and Research Associate in the Allan Hancock Foundation Curator of Malacology, Emeritus University of Southern California, Los Angeles Stanford University, Stanford, California Dr. J. Wyarr Duruam, Professor of Paleontology Dr. Victor Loosanorfr, Professor of Marine Biology University of California, Berkeley, California Dr. E. W. Facer, Professor of Biology Dr. Joun McGowan, Associate Professor of Scripps Institution of Oceanography, La Jolla Oceanography University of California at San Diego Pacific Marine Station of the University of the Pacific Scripps Institution of Oceanography, La Jolla Dr. Caner Hanp, Professor of Zoology and University of California at San Diego Director, Bodega Marine Laboratory Dr. Frank A. Pire.xa, Professor of Zoology UnNenty ol Calitonia, Henley, Calor University of California, Berkeley, California Dr. G Datias Hanna, Curator Mr. Attyn G. Smiru, Associate Curator Department of Geology eae 3 . Department of Invertebrate Zoology California: Academy, oii cienees fear brane co California Academy of Sciences, San Francisco Dr. Joet W. Hepcpetu, Resident Director : Barve Dr. R le Marine Science Laboratory, Oregon State University By RauPHsl Surrey, Professors Ze cley Newport (Oren University of California, Berkeley, California Dr. Cuarzes R. StTasek, Associate Professor of Zoology Florida State University, Tallahassee, Florida EDITOR-IN-CHIEF ASSOCIATE EDITOR Dr. Rupotr STou er, Research Zoologist, Emeritus Mrs. JEAN M. Cate University of California, Berkeley, California Los Angeles, California —U!- — A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California VOLUME 14 October 1, 1971 NuMBER 2 CoNnTENTTS Distribution and Zoogeography of Fourteen Species of Nudibranchs of Northern New England and Nova Scotia. (14 Text figures; 1 Map) KANIAULONO BatLey MEYER . = 7: (a aeons, MaRS te he hi 6 Description of Doto (Doto) fragilis nipponensis subspec. nov. from Sagami Bay, Japan (Nudibranchia : Dendronotoidea : Dotoidae). (1 Text figure) KrikuTARO BaBa BS Gece RRR ARE RE eee ais Se Non ome Ine SOREN recA The Biology and a Redescription of the Opisthobranch Mollusk Hermaea cruciata Gould, from Chesapeake Bay (Sacoglossa : Hermaeidae). (1 Plate; 2 Text figures) Rosauie M. VocEL Studies on the Food of -Nudibranchs. James W. McBeru Range Extensions of Some Northeast Pacific Nudibranchs (Mollusca : Gastropoda : Opisthobranchia) to Washington and British Columbia, with Notes on their Biology. Gorpon A. RosILLiARD : Veliger Development in Dendronotus frondosus (Ascanius, 1774) (Gastropoda : Nudibranchia). (5 Text figures) Lesure G. WILiiams Ahr Re On the Reproductive Biology of Mitra idae (Gastropoda : Mitridae). (3 Plates; 4 Text figures) James R. Cuess « RicHarp J. RosENTHAL Homing Behaviour and Population Regulation in the Limpet Acmaea (Collisella) digitalis. IPAS, JoX LEIS 9 3, 6) 6 OMe EOMIDN ROS EO) 0 6.0 OG [Continued on Inside Front Cover] Distributed free to Members of the California Malacozoological Society, Inc. - 137 - 155 . 158 Belg2 Subscriptions (by Volume only) payable in advance to Calif. Malacozool. Soc., Inc. Volume 14: $18.- Domestic; $19.- in the Americas; $19.50 in all other Foreign Countries Single copies this issue $12.-. Postage extra. Send subscription orders to Mrs. JEAN M. Cate, 12719 San Vicente Boulevard, Los Angeles, California 90049. Address all other correspondence to Dr. R. STOHLER, Editor, Department of Zoology, University of California, Berkeley, California 94720 Second Class Postage Paid at Berkeley, California ConTENTs — Continued Predation of Marisa cornuarietis on Oncomelania formosana Eggs under Labora- tory Conditions. (1 Text figure) Lois Wonc Cut, Linpsay R. WINKLER & RutH CoLvIN, « ...... « 184 Contribution to the Taxonomy of the Muricidae (Gastropoda : Prosobranchia). (1 Plate; 1 Textfigure) Water, ©) CERNOHORSKY , 20:0. ¢ ~ tC On cn Rn on pe Effect of Scorpion Venom on the Ciliary Activity of Fresh Water Mussel. (2 Text figures) D. CHENcAL Raju, R. V. KrisHNAMOORTHY & A. SUBBARAMI REDDI. . . . . 192 The Effect of Storms as a Density Dependent Mortality Factor on Populations of Sea Mussels. (6 Text figures) J. R..E.. Harcer,« BD: E. LANDENBERGER«; = 4, 2 0ss 0. te eae Gane Ey Cell Renewal Systems in the Gut of the Oyster, Crassostrea gigas (Mollusca : Bivalvia) . (2 Plates) MicHAEL 'G. Mie. 25.025 ao a Sih ea Ce nes caer eohedas ie rc Or Field Identification of Crab Predation on Shaskyus festivus and Ocenebra poulsont (Prosobranchia : Muricidae) . Nick FOTHERINGHAM © 20.0! Bese 1h Rae ers ek ci Thais emarginata (Deshayes): Description of the Veliger and Egg Capsule. (8 Text figures) RENEE LEBORUR e729 je iis a0! ae nel ol So nee Ae ee ohne ey METHODS & TECHNIQUES .. . Sis EDT, A Mesofaunal Collecting Kit for SCUBA Wark in me Waters. (1 Text figure) J. SHERMAN BLEAKNEY NODES & NEWS 0 ieee Pern eS on 624) The Reinstatement of Hopeib donate agassizi (Bergh, 1894) (Mollusca : Opisthobranchia) . Gate G. SPHON Eubranchus misakiensis Baba, 1960 (Nudibranchia : Eolidacea) in San Francisco Bay. Davin W. BEHRENS New Record of a Color Variation in Spurilla oliviae. (1 Text figure; 1 Map) Gary C. WILLIAMS BOOKS, PERIODICALS) & PAMPHIELE DS ==) sean al tined on nmin ee -we-Bee Note: The various taxa above species are indicated by the use of different type styles as shown by the following examples, and by increasing indentation. ORDER, Suborder, DIVISION, Subdivision, SECTION, SUPERFAMILY, Famity, Subfamily, Genus, (Subgenus) New Taxa Vol. 14; No. 2 THE VELIGER Page 137 Distribution and Zoogeography of Fourteen Species of Nudibranchs of Northern New England and Nova Scotia BY KANIAULONO BAILEY MEYER’ Systematic and Environmental Biology, Biological Sciences, University of Connecticut, Storrs, CT 06268 (14 Text figures; 1 Map) INTRODUCTION THERE HAS BEEN no detailed analysis of the nudibranch fauna of the northwestern Atlantic shores. Information as it now exists is a result of occasional collections in New England by workers of the past century, most notably those of Goutp (1870), Verrmz (1873), and, more re- cently, Moore (1950, 1964). Work on the Canadian shores consists of collections on Grand Manan Island, New Brunswick, by Stimpson (1853) but, although La Rocgue (1953) lists a number of species for Canada, for the greater part the reports are merely northern limits of the New England collections. Thus it is the purpose of this paper to consider in greater detail the distributions and zoogeographical re- lationships of 14 species of nudibranchs collected inter- tidally along New England north of Cape Cod, Massa- chusetts to and including Nova Scotia. Due to the difficulties of identification of nudibranchs, systematic descriptions and comments are included. STATIONS COLLECTED Stations and dates at which collections were made are noted in the Figure of the map with species collected at each indicated by symbols. Stations 3, 4, 6, 9, 10, 12 were collected over a period of 3 years, whereas the other sites were chosen due to their rocky shore ecology, since this is a habitat preferred by most nudibranchs whose food preferences are sedentary animals such as hydroids, ectoprocts, barnacles, and sea anemones. Species collec- ted during the summer of 1968 are the only ones dealt with since the actual material from previous years was not available for study. " Present address: Smithsonian Tropical Research Institute, P O. Box E, Coco Solo, Canal Zone TAXONOMIC NOTE Although the mandibles of the suborders Dendronotacea (with the exception of Doto) and the Eolidacea are im- portant taxonomically, the Doridacea are notable in that they lack mandibles. In the 5 species of dorids here studied, a chitinous lining of the buccal mass was extrac- ted using methods similar to those for mandible extrac- tion, e. g., dissolving of the tissue in full strength Clorox or in a hot solution of dilute potassium hydroxide. The taxonomic use of this structure has not appeared in the literature, but it appears to be a useful character since it shows distinct morphological differences both within a family (e. g., between the species Acanthodoris pilosa and Onchidoris fusca of the Onchidoridae) and even within a genus (Onchidoris). However, in order to estab- lish how widely useful this character may be, more work is needed on a broader representation of dorids. SPECIES DESCRIPTIONS In the following descriptions, the full number of teeth in one radular row is given with variations indicated in parentheses. “D” is used to indicate the largest or domi- nant tooth in a row. Acanthodoris pilosa (Abildgaard, 1789) Doris pilosa Abildgaard, 1789. In Mtxer, Zool. Da- rarer), Gol, 3k Be 7/ Doris stellata Gmelin, 1791. In Linn. Syst Nat. ed. 13, PASO Doris nigricans Fleming, 1820. Edinb. Encycl. (Brew- ster), 14: 618 Doris sublaevis Thompson, 1840. Ann. Mag. Nat. Hist. 5: 87 Page 138 THE VELIGER Vol. 14; No. 2 16 SLOIA AO New Brunswick O11 OMAC+ Wernant O 5 6MA+-0o+ 4 SBAAODX 2 ZAA® New Hampshire Gulf of Maine © Acanthodoris pilosa + Facelina bostoniensis @ Onchidoris fusca A Coryphella stellata @ Onchidoris muricata © Coryphella verrucosa Ancula gibbosa = Cuthona concinna Ho Polycera dubia Tergipes tergipes A Dendronotus frondosus x Eubranchus olivaceus A Doto coronata + Aeolidia papillosa Map showing collecting sites and the distribution of species. Collection dates indicated in parentheses. 1. Manomet, Massachusetts (28 May, 1968; 25 April, 1969) g. Kingsport, Nova Scotia (1966 - 1968) 2. Kennebunk, Maine (1967 - 1968) 10. Black Rock, Nova Scotia (1966 - 1968) 3. Cousins Island, Maine (1967 - 1968) 11. Cape Sable Island, Nova Scotia (9 July, 1968) 4. Bailey’s Island, Maine (6 June 1968) 12. Hunts Point, Nova Scotia (8 July, 1968) 5- Walpole, Maine (November, December, 1968; February, 1969) 13. La Have, Nova Scotia (27 June 1968) 6. Swans Island, Maine (1966 - 1968) 14. Kingsburg, Nova Scotia (4 July, 1968) 7. Coobscout State Park, Maine (11 June, 1968) 15. The Ovens, Nova Scotia (26 June, 1968) 8. Eastport, Maine (13 June, 1968) 16. Louisburg, Nova Scotia (16-18 June, 1968) Vol. 14; No. 2 Doris similis Alder & Hancock, 1842. Ann. Mag. Nat. lista 92032 Doris rocinella Leach, 1847. Ann. Mag. Nat. Hist. 20: 268 Acanthodoris pilosa Gray, 1850. Figs. Moll. Anim. 4: 103 Doris bifida Verrill, 1870. Amer. Journ. Sci. 50: 406 Acanthodoris citrina Verrill, 1879. Amer. Journ. Sci. 7 SN; Acanthodoris ornata Verrill, 1879. Amer. Journ. Sci. 17: 314 Acanthodoris pilosa, Chaster et al., 1901. Journ. Conch. 10: 26 Body oval, oblong, up to 34mm. Dorsum convex, margins fluid, covered with numerous soft, slender, coni- cal papillae of almost uniform size. Foot broad, rarely pro- jecting beyond notum except posteriorly. Rhinophores large, inflated at the base, tapering distal- ly to the base of the lamellae, tips angled posteriorly. Lamellae 18, sheath fringed. Branchial plumes large, delicate, doubly pinnate or occasionally imperfectly tripinnate, covering the whole posterior region, retractile but lacking a sheath. Color variable: white, yellow, light purple, purple- brown, or sometimes appearing black. Dark colors not uniform, 7. e., may be rendered by close approximation of discrete points of color. Rhinophore lamellae yellow. Branchial plumes with granular white bodies along axes. Radula with 34 rows of teeth. Formula: 4: D-0-D- f. Dominant tooth large (Figure la), about 475 long, heavy along expanded edge. Cusp curved, blunt, bearing short lateral serrations. Lateral teeth small, linear, pointed on one end, blunt on inserted edge (Figure 1b). 100 400). —— —— Figure 1 Acanthodoris pilosa a. Dominant tooth b. Two lateral teeth c. Lining of buccal mass THE VELIGER Page 139 Buccal lining expanded dorso-ventrally, 1.2><1 mm in a specimen 25 mm long; radular ribbon inserted posterior- ly rather than ventrally as in Onchidoris (Figure Ic). Habitat: Acanthodoris pilosa is common on the alga As- cophyllum bearing the ectoproct Flustrellidra hispida upon which it feeds. The egg mass is ribbon-like, attached along one edge and lying in a loose coil on the Ascophyl- lum. Egg diameter 12u. Onchidoris fusca (O. FE Miller, 1776) Doris fusca Miller, 1776. Zool. Danica Prod. 229, no. 2768 Doris bilamellata Linnaeus, 1767. Syst. Nat. ed. 12, p. 1083 (partim) Doris coronata Agassiz, 1851. Proc. Boston Soc. Nat. Hist. 3: 191 (nomen nudum) Doris elfortiana Blainville, 1816. Bull. Sci. Soc. Phil- om. Paris p. 95 Onchidoris leachi Blainville, 1816. Bull. Sci. Soc. Philom. Paris p. 97 Doris affinis Thompson, 1840. Ann. Mag. Nat. Hist. Jp th) Doris liturata Beck, 1842. Naturhist. Tidsskrift. 4: 78 Doris vulgaris Leach, 1847. Ann. Mag. Nat. Hist. 20: 268 Onchidoris fusca, Winckworth, 1932. Journ. Conch. Soc. London 19: 231 Body elliptical, up to 33mm, sides nearly parallel, equally rounded. Margins fluid, waved. Foot narrower than body, somewhat truncate behind, never projecting beyond notum. Head as broad as foot, crescentic. Tail pointed, narrower than foot. Rhinophores short, retractile, somewhat compressed, upper 2 obliquely lamellated, lamellae not meeting be- hind, tip knobbed. Notum covered with short, pestle-shaped tubercles of variable size. Branchial plumes 20-30 in number, long, slender, singly pinnate, set in an elliptical groove around the anus, with an included space covered by several tubercles. Color dull cream with numerous brown markings cre- ating a marbled appearance. Brown markings form 3 indistinct longitudinal bands. Radula with 28 rows. Formula: 1:-D-1-D-1. Domi- nant tooth about 150 broad, 250 high, strongly cusped, tip pointed, moderately heavy (Figure 2a). Buccal lining similar to that of Onchidoris muricata except for a nonserrate edge. About 1 mm long, 0.5 mm at the widest point from a specimen 25 mm long (Figure 2b). Page 140 0.4mm Figure 2 Onchidoris fusca a. Dominant tooth b. Buccal lining Habitat: Onchidoris fusca was collected from ecto- procts and Balanus-encrusted rocks, preferring Balanus balanoides as a food organism. Eggs are extruded in a tape-like mass, attached along one edge in a coil of 1 to 2 turns. Onchidoris muricata (O. F. Miller, 1776) Doris muricata Miller, 1776. Zool. Danica Prod. > BAY Doris aspera Alder & Hancock, 1842. Ann. Mag. Nat. labigt, Qe BP Doris diaphana Alder & Hancock, 1845. Ann. Mag. Nat. Hist. 16: 313 Doris ulidiana Thompson, 1845. Ann. Mag. Nat. Hist. 15: 312 Doris pallida Agassiz, 1850. Proc. Boston Soc. Nat. Hist. 3: 191 (nomen nudum) Proctaporia fusca Morch, 1857. Groenl. Cat. 78, Groenl. Boddyr. 6 Onchidoris pallida Verrill, 1870. Amer. Journ. Sci. 50: 408 Onchidoris muricata, Winckworth, Conch. Soc. London 19: 231 1932. Journ. Body elongate, elliptical, about 12mm long, half as wide, sides parallel, 2 ends equally rounded. Foot narrow- er than mantle. Head as broad as foot, short, crescentic. Tentacles long, recurved, with 10 oblique lamellae on the upper # of the rhinophores. Sheath lacking. Notum covered with numerous mushroom-shaped tu- bercles, becoming more pointed and more numerous to- THE VELIGER Vol. 14; No. 2 ward the margins. Spicules large, especially notable in a stellate pattern at the bases of the tubercles. Branchial plumes singly pinnate, 9-11 in number, retractile into separate hollows, set in a nearly closed circle around the anus. Anterior plumes slightly larger than posterior. Color white, rarely pale yellow. Body translucent, tu- bercles more opaque. Dusky pear-shaped spot of diver- ticulum shows through dorsally and ventrally. Radula of about 17 rows. Formula: 1-D:0°D-1. Dominant tooth 50u at widest point, 75 at highest. Blade thin, bearing a short, heavy, blunt cusp with a lateral serrate edge (Figure 3a). Lateral tooth stout, roughly rectangular, bearing a lateral blunt hook (Figure 3b). a 25. Figure 3 Onchidoris muricata a. Dominant tooth b. Lateral tooth c. Buccal lining Buccal lining 2 mm long in a 10 mm long specimen, lip wide, neck narrow, broadening to a lobulate portion 0.8 mm at the widest point. Edges serrate, radular ribbon set ventrally just posterior to lip (Figure 3c). Habitat: Onchidoris muricata is possibly the most com- mon dorid of the New England coast and Nova Scotia. It feeds on the ectoproct Electra pilosa which encrusts the underside of rocks. Ancula gibbosa (Risso, 1818) Tritonia gibbosa Risso, 1818. Journ. Physique 87: 371 Polycera cristata Alder, 1841. Ann. Mag. Nat. Hist. 4: 340 Ancula sulphurea Stimpson, 1854. Smithson. Contr. Knowl. 6: 26 Ancula gibbosa, Pruvot-Fol, 1954. Faune de France 58: 312 Vol. 14; No. 2 Body linear, slender, up to 13mm in length, higher than broad. Foot narrow, rounded at sides, sometimes contracting to a line. Rhinophores large, clavate, upper 3 covered by 10 lamellae which meet posteriorly. Two long, anteriorly di- rected projections arise Just above the rhinophore bases. Three non-retractile branchial plumes, triangular, doub- ly pinnate, arranged in a semicircle, anterior largest, flanked by 5 - 8 long, slender tubercles on either side. Body translucent white with inner organs visible. La- mellae of rhinophores and tips of rhinophore projec- tions, tubercles, and branchial plumes very pale to deep lemon yellow, the color sometimes in discrete spots and mixed with opaque granules. Radula of about 30 rows. Formula: 1°:D-1-D-°-1. Dominant tooth 654 high, 45 wide, obliquely curved anteriorly on upper margin, this margin bearing about 12 heavy serrations; base thickened (Figure 4b). Outer lat- eral tooth thin, linear with a sharp hook (Figure 4c). Median tooth small, stout, roughly doubly pyriform with 2 sharp points (Figure 4a). 25 Figure 4 Ancula gibbosa b. Dominant tooth d. Buccal lining a. Median tooth c. Lateral tooth Buccal lining of a 15 mm specimen about 0.9 mm long with a dorsal pouch connecting to the main mass by a short, broad neck. Collar corticated ventrally (Figure 4d). Habitat: This is a common species found feeding on ectoproct-covered rocks at low tide. Food source not de- termined. Egg mass a short, narrow ribbon, serpentine in habit and attached along one edge; about 15 mm long. Eggs 9 - 12 in diameter. THE VELIGER Page 141 Polycera dubia Sars, 1829 Polycera dubia Sars, 1829. Bidr. Soedyr. Naturh. 13: 286 Polycera lessonu d’Orbigny, 1837. Mag. Zool. Classe 5. Ws 5 Doris illuminata Gould, 1841. Invert. Mass. p. 4 Polycera citrina Alder, 1841. Ann. Mag. Nat. Hist. 6: 340 Polycera ocellata Alder & Hancock, 1842. Ann. Mag. Nat. Hist. 9: 33 Polycera modesta Lovén, 1846. Ofvers. K. Vetensk. Acad. Forh. Stokhl. 8: 138 Polycera dubia, Pruvot-Fol, 1954. Faune de France 58: 319 Body elongate, 16 mm long, somewhat contracted pos- terior to rhinophores, tapering to a blunt point posterior to branchial plumes. Head nearly semicircular, with a hood notched in the medial line and having 6 - 7 project- ing tubercles on each side which continue to the posterior edge of the branchial region as a lateral tubercle-bearing ridge. Branchial plumes doubly pinnate, 3 in number, the middle being the largest. Dorsum bearing low tubercles of various sizes. Rhinophores short, non-retractile, clubbed with 8 ob- lique lamellae (not 12 - 13 as stated in Goutp, 1870). Foot square in front, slightly dilated at angles, sides 0.4mm (Le Figure 5 Polycera dubia b. Median tooth d. Lateral teeth a. Buccal lining c. Dominant tooth Page 142 parallel, flared either side of the body posterior to bran- chial area, blunt posteriorly. Color pale to dark green. Tubercles, rhinophore clubs and branchial plumes tipped with pale to dark yellow. Radula with 13 rows. Formula: (3-6):-D°2-2-D- (3-6). Dominant tooth heavy, 140 high, hooked, over- lapping the 2 smaller hooked median teeth (Figures 5b, c). Laterals 60 high, heavy, rectangular (from a specimen 10mm long) (Figure 5d). Buccal support with a chitin- ous part nearly rhomboidal, upper half heavier than lower (Figure 5a). Habitat: Polycera dubia was found all along the coast near the low water mark beneath ectoproct encrusted rocks. Food source was not determined nor were eggs located. Dendronotus frondosus (Ascanius, 1774) Since Rosituarp (1970) has recently given a complete revision of the synonymy of this species, none will be given here. Body linear, up to 80mm long, rather higher than broad, laterally compressed, pointed behind with slightly rounded dorsum. Dorso-lateral margins bearing 3 - 6 pairs of cerata strongly branched in large individuals, dimin- ishing in size posteriorly. Dorsum may be sparsely covered with numerous small papillae. Foot thin, delicate, showing viscera ventrally, prehensile. Velum narrow, rounded, bearing 5 - 6 branching pro- cesses with smaller ones between. Rhinophore sheath with 4 - 5 arborescent marginal pro- cesses, with one at the posterior of base also. Rhinophores clubbed with 5 - 6 transverse lamellae. Cerata containing extensions of the diverticulum in specimens up to 14mm; 18 mm specimens with the ex- tensions receded halfway; absent in larger specimens. Anal papilla medial to the first ceras on the right. Reproductive opening about 1 mm behind the base of the right rhinophore. Cardiac region forming a hump just behind the first pair of cerata. Color variable, maroon or red marbled with brown and opaque white or rose or white marbled with brown and yellow. Some quite pale and translucent, some with 1 - 3 opaque patches along the median dorsal line, others dark brown. Color extending over the whole body with the foot generally paler than the body. Radula tapering, bearing 33 - 34 rows of teeth. Radula formula: (9 - 15) -1- (9-15). Median tooth broad, 250u high, 200 broad, heavy, with multidenticulate triangular THE VELIGER Vol. 14; No. 2 cusp (Figure 6a). Laterals long, tips curved, outer mar- gins serrate (Figure 6b). 100). ae tebe Figure 6 Dendronotus frondosus a. Dominant tooth b. Lateral tooth Mandibles yellow, ovate, hooked posteriorly. Mastica- tory border with a single series of small, rounded denticles. Habitat: This species was abundant along the whole collecting area feeding on the hydroid Sertularia pumila and rarely on Tubularia sp. Most numerous were individu- als between 2 and 10mm, but adults were by no means lacking. The egg mass is highly convoluted, attached to Ascophyllum by a mesentery at a central point. Eggs measure 32 - 36 in diameter, tending to be slightly ovate. Doto coronata (Gmelin, 1791) Doris coronata Gmelin, 1791. In Linn. Syst. Nat. ed. 118}, hg BIOs Doris maculata Montagu, 1804. Trans. Linn. Soc. London 7: 80 Doris pinnatifida Montagu, 1804. Trans. Linn. Soc. London 7: 78 Meliboea ornata Alder & Hancock, 1842. Ann. Mag. Nat. Hist. 9: 34 Meliboea arbuscula Agassiz, 1851. Proc. Boston Soc. Nat. Hist. 3: 191 (nomen nudum) Doto coronata, Lemche, 1962. Bull. Zool. Nomen. 19: 156 - 159 Body long, slender, sides high, up to 8 mm long, dorsum convex, tapering to a pointed tail. Foot as broad as body, anterior angles rounded, tapering to a poimted tail. Oral tentacles reduced to anterior lobes of the head. Rhinophore sheath trumpet-shaped, rhinophore clubs smooth, slender, tapering to a point. Vol. 14; No. 2 Cerata clavate, inflated, arranged in 4 - 7 pairs begin- ning just behind the rhinophores and becoming smaller posteriorly. Bases slender, cerata encircled by 4 - 5 tiers of low tubercles with one terminal tubercle. Genital opening just below the first right ceras. Base color cream with dense or scattered stellate mott- lings of red-brown extending over the body surface and rhinophore sheaths. Rhinophore clubs tipped with opaque white. Cerata tubercles tipped with a red spot often sur- rounded with an opaque white ring. Orange diverticulum sometimes showing through the cerata. 12 fe Seo rar Figure 7 Doto coronata a. Tooth Radula uniseriate with about 69 teeth. Tooth heavy, 20u wide, 25 high, deeply cleft from insertion nearly bisecting the tricuspid pinnacle. Tooth spanned by a heavy, open V-shaped thickening (Figure 7a). No mandibles present. Habitat: Doto coronata occurs over the entire length of the study area, feeding on Sertularia pumila. The egg mass is strap-like, about 5 mm long, | - 2 mm wide, laid in a loose undulating manner on the hydroid. Egg diameter 10u. Facelina bostoniensis (Couthouy, 1838) Eolis bostoniensis Couthouy, 1838. Boston Journ. Nat. Hist. 2: 67 Facelina bostoniensis, Verrill & Emerton, 1880. Proc. U.S. Nat. Mus. 3: 389 Body elongate, lanceolate, up to 25mm long, broad anteriorly, tapering to a fine point posteriorly. Foot with anterior lateral corners forming sharply acute angles ex- tending well beyond the lateral margins of the head and angled posteriorly. THE VELIGER Page 143 Oral tentacles about + body length, broad at their bases, tapering to a point, often curved posteriorly or held anteriorly forming a broad horseshoe. Rhinophores erect or slanted slightly anteriorly, ringed with alternately large and small lamellae about 24 in number, the most ventral of which being least well de- veloped. Cerata lanceolate, set off in 2 distinct clusters, each composed of oblique ranges of cerata. ‘The first cluster set off on a slight protuberance creating a “ruff about the shoulders,’ with 5-6 ranges each composed of 8 - 12 cerata. The second cluster of 3-6 ranges some often indistinct, especially the most posterior where the cerata of both sides tend to mingle. Ranges, where distinct, of 5-10 cerata each. Most dorsal cerata longest, curved posteriorly to middorsal line. Cerata becoming shorter ventrally. Anal papilla set posterior to second range of cerata of second cluster. Base color translucent white to buff, head often of rosy hue. Tentacles with a blue-white interrupted line along the dorsal surface. Rhinophores opaque brown distally with a blue-white line on the proximal half. Interrupted opaque white or blue white line on the proximal half. Similar line between the rhinophore extending posteriorly a short distance. Middorsal line of tail with blue-white marking. Diverticulum russet or brown, filling the cavity of the ceras or contracted to an irregular line; tip surrounded by an opaque white ring more concentrated on the outer side. Radula with 14 teeth. Median denticle strong, flanked by 2 lateral denticles which arise in such a way as to create an almost tridentate appearance. Denticles lateral to the median denticle strong, variable (6-7), pointed admedially (Figure 8a). New teeth with lateral denticles weakly developed. AN 1.0 mm Figure 8 Facelina bostoniensis a. Tooth b. Mandibles c. Inner view of left mandible Page 144 Mandibles broadly oval, thin, with weak hinge. Each jaw with a prominent ridge in the hinge area. Mastica- tory process } the height of the jaw, lined by 16 well- developed denticles which become wom toward the hinge region (Figures 8b and 8c). Habitat: This species was collected from the hydroid Obelia sp. growing on Laminaria. The egg mass loops gracefully over the hydroid and measures about 25 mm in the looped state. Remarks: Bercu (1886) gives a description of Facelina bostoniensis and comparison of the Maine specimens to his plates and text shows that these may be identified with that species. However, consultation of the text and plates given by Bercu (1875, 1877, 1878) for F drum- mond, F janu, and F. panizzae (all of which are synonyms of FE auriculata (Miller, 1806) according to ODHNER, 1939) raises the question as to whether F bostoniensis is actually F auriculata. The specific differences among the facelinids of the North Atlantic are, in most cases, very slight and species described as separate taxa are often found to be one species. Bergh, for example, gives descrip- tions of F drummondi, F. janii and F. panizzae in the same paper (1875), but later acknowledges the synonymy of the last 2 with EF drummondi (1891). He stresses the shape and disposition of the penial spines (1875, p. 407, footnote 1) as specific differences yet he does not seem to take variability into consideration so that, even though F jani possesses spines on the surface of the penial leaf as well as along the margin (a condition not considered to be characteristic of F drummondi by Brercu, 1875), it was still synonymized at a later date. Therefore, F auriculata (= E drummondi) may show great variation in penial armature and the taxonomic importance of this character, as far as number of rows and disposition of spines is concerned, is open to question. Given this, FE bostoniensis (with spines in 1 - 3 rows along the margin of the penial leaf; the male opening on the underside proximal to the margin of the leaf, 14 - 40 teeth each with 4-6 denticles lateral to the median denticle) may very well be identical with F auriculata, but until material of both the European “species” and the American “species” is examined, no synonymizing can take place. Coryphella stellata (Stimpson, 1853) Eolis stellata, Stimpson, 1853. Smithson. Contr. Knowl. 6: 25 Coryphella stellata, Johnson, 1915. Occ. Pap. Boston Soc. Nat. Hist. 7: 166 Body linear, 16 mm in length, tapering to a point. Foot narrow, anterior angles about as long as width of foot, THE VELIGER Vol. 14; No. 2 2. €., twice the length of those of Coryphella verrucosa, and very acutely angled. Oral tentacles long, delicate, tapering. Rhinophores shorter than tentacles, heavier, blunt and wrinkled. Cerata relatively few in number, linear, slightly lanceo- late or variable in diameter and length, arranged in 5 clusters, the first having 15 - 23 cerata with the anterior margin just below the rhinophores, the rest with about 10 cerata each, fewer in smaller individuals. Anal papilla just below anterior edge of second cerata cluster. Penis conical when extruded. Base color translucent white. Oral tentacles sparsely flecked distally with an opaque white band. Cerata deep pink in all individuals, filling the cavity completely. Radula slightly tapering, with about 13 teeth. Formula: 1-D-1. Dominant tooth with a prominent median dent- icle and 5-7 admedially pointed laterals, about 50u wide, 85u high (Figure 9a). Lateral teeth much larger than those of Coryphella verrucosa with a deeply serrate edge (Figure 9b). Figure 9 Coryphella stellata a. Dominant tooth b. Lateral tooth c. Anterior view of mandibles d. Inner view of left mandible e. Lateral view of left mandible Mandibles thin, subglobular with strong hinge con- nective and denticulated masticatory process about 4 height of jaw. Inner surface with a roughly punctate yellow thickening about 4 the way below masticatory edge (Figures 9c, 9d, Ye). Habitat: This species is found only at Kingsport, Nova Scotia, feeding on the hydroid Eudendrium sp. The egg Vol. 14; No. 2 string is a very narrow loop over the hydroid. Egg dia- meter 8. Remarks: The genus Coryphella includes several species with very similar gross morphology. In order to differen- tiate these species, it is necessary to examine such char- acters as position of the anus, clustering of the cerata, the radula and penis. Since the species here designated C. stellata has not appeared in the literature since its original description by Stimpson (1853, from Grand Manan, New Brunswick), it is prudent to compare it with the 3 European species it most closely resembles. Coryphella stellata is characterized by having the anus located just anterior to the second cluster of cerata, long foot angles, a conical penis, a radula of consistently (at least in 3 specimens) 13 rows of teeth with the median tooth bearing 5 - 7 lateral denticles and the lateral tooth bearing 4-7 serrations. Of the European species, it most closely resembles C. pellucida (Alder & Hancock, 1843) externally in the position of the anus, the long foot angles, the conical penis and coloration. However, it dif- fers in 2 important aspects: C. pellucida has 35 - 45 rows of teeth and the lateral teeth are smooth, not serrated (OpHNER, 1939). Coryphella lineata (Lovén, 1846) shows even closer affinities to C. stellata, differmg primarily in that the number of tooth rows in the former varies from 13 to 20, the lateral tooth bears 12- 14 serrations and the penis is discoid. It is more difficult to differentiate between C. stellata and C. gracilis (Alder & Hancock, 1844), the latter differing in that the anus is located below the third row of the second cluster of cerata. Additional support for the differences between these 2 taxa is provided by LemcuHe (1941a) who noted that the specimens he had identified as C. gracilis (1935, 1938) were actually C. verrucosa. Even in the preserved state C’. stellata cannot be mistaken for C. verrucosa. Additional differences of note are: (1) the larger size of the European species which are about 25 mm whereas the 6 specimens of Coryphella stellata ranged from 6 to 16 mm, some being mature, as evidenced by several egg masses; and (2) the fact that the cerata of the European species are neatly grouped in oblique rows with each ceras lying posteriorly along the dorsum. Coryphella stellata has its cerata in more vertical rows which are shorter than those of other coryphellids. The cerata are consistently of assorted sizes and tend to be held perpen- dicular to the body. Some of the cerata are larger in pro- portion to the body than those of other species. Comparison of the radula of the Kingsport specimens with a radula (median teeth only) mounted by A. E. Verrill of a specimen collected at Eastport, Maine and identified by him as Coryphella stellata shows them to be identical. THE VELIGER Page 145 From this discussion it is evident that Coryphella stel- lata is a distinct species and, although Stimpson’s descrip- tion is brief, it is sufficient to warrant applying his specific name to the specimens found in Nova Scotia. Coryphella verrucosa (Sars, 1829) Eolidia verrucosa Sars, 1829. Bidr. Soedyr. Naturh. [Pb W) Eolis rufibranchialis Johnston, 1832. Mag. Nat. Hist. London 5: 428 Eolidia embletoni Johnston, 1835. Mag. Nat. Hist. London 8: 378 Eolis mananensis Stimpson, 1853. Smithson. Contr. Knowl. 6: 26 Coryphella verrucosa, Winckworth, 1932. Journ. Conch. 19: 36 Body elongate, slender, up to 28 mm long, tapering to a thin point. Foot narrow, translucent, anterior angles about half as long as width of foot, acutely edged. Rhinophores wrinkled, moderately tapered, about same length as oral tentacles. Cerata slender, lanceolate, variable in length, being longer dorsally and becoming shorter ventrally; arranged in 3-5 clusters on each side, opposite clusters meeting to form a V-shape along their anterior margin. First cluster with 14 - 20 cerata, second with 7 - 16, third with 7 - 15, fourth with 7 - 14, fifth with 6 - 8. 0.6mm (| Figure 10 Coryphella verrucosa a. Lateral tooth b. Dominant tooth c. Anterior view of mandibles d. Lateral view of right mandible e. Inner view of left mandible Page 146 Anal papilla just anterior and ventral to the second cluster of cerata. Base color translucent white with a white stripe along the dorsal edges of the tentacles, rhinophores, and tail. Rhinophores with an orange tinge. Cerata diverticulum olive, orange, russet, or brown, filling the ceras or con- tracted to 4 the diameter of the ceras. Opaque white circle near the tip of the ceras. Radula non-tapering, 10-17 rows. Formula: 1-D- 1. Dominant tooth heavy, 250y in height, 1504 wide, with a large median denticle and 5 - 9 lateral, well developed denticles (Figure 10b). Lateral teeth triangular with one serrate edge (Figure 10a). Mandibles thin, oval in front view, roughly triangular in lateral view. Hinge strong, masticatory border short, weakly denticulated with a yellow irregularly textured “callus” forming an elongated triangular process along the inner edge of the anterior jaw margin below the masticatory process (Figures 10c, 10d, 10e). Habitat: Coryphella verrucosa is common on the north- ern shores beneath rocks. Eggs are laid on rocks in a loose coil of 4-6 turns. Cuthona concinna (Alder & Hancock, 1842) Eolis concinna Alder & Hancock, 1842. Ann. Mag. Nat. Hist. 12: 234 Cuthona concinna, Eliot, 1910. Brit. Nudibr. Moll. Ray Soc. London, p. 173 Body elongate but broad, up to 10 mm in length. Foot wide, anterior margins bluntly angled, tapering only slightly to a sharp tail. Oral tentacles long, stout, gently tapered. Rhinophores about same length as tentacles, but more slender and blunt. Cerata moderately long, of variable size with the longest dorsally placed, inflated, tips sharply pointed; 20 - 30 on a side, beginning just ventral to the rhinophore bases. Eyes well behind the rhinophores about the level of the the fourth cerata. Base color translucent white. Distal half of rhinophores opaque white, tinged with rust proximally. Tentacles tipped with dense opaque white. Tips of cerata with a circlet of white with a few flecks scattered proximally. Diverticulum yellow-brown to rust, showing through dor- sum as paired spots just posterior to the rhinophores and in one or two spots behind these, extending into the cerata as a thin, irregular core about 4 the diameter of the ceras, but sometimes filling it. Radula tapering with about 27 teeth. Formula: 1-D- 1. Dominant tooth hooked, 354. wide, 100m high (Figures THE VELIGER Vol. 14; No. 2 lla, 1lc). Median denticle and 5 lateral denticles of about equal size. Lateral teeth triangular, sharply pointed, with 6 serrations (Figure 11b). 0.2mm Figure 11 Cuthona concinna a. Lateral view of dominant tooth b.Upper part of lateral tooth c. Anterior view of dominant tooth d. Lateral view of outer side of left mandible e. Lateral view of inner side of left mandible Mandibles thin, 0.9 mm in height (from a 10 mm spe- cimen). Masticatory border short, finely denticulated, elevated from the mandible proper (Figures 11d, 11e). Habitat: This species was collected in rocky pools under rocks. No food preference was determined nor were any egg masses located. Tergipes tergipes (Forsskal, 1775) Limax tergipes Forsskal, 1775. Desc. Anim. p. 99 Eolidia despecta Johnston, 1835. Mag. Nat. Hist. London 8: 378 Tergipes tergipes, 1966. Op. 773, I.C.Z.N. Bull. Zool. Nomencl. 23: 84 Body linear, slender, truncate anteriorly, 10mm in length, tapering to a point. Foot narrow, anterior angles rounded, rarely seen from dorsal aspect. Oral tentacles short, of uniform diameter, with rounded tips. Rhinophores longer than oral tentacles, slightly tapered with blunt tips. Cerata few, 4, rarely 5 on a side, clavate with slender pedicle and dilated near tip. Vol. 14; No. 2 THE VELIGER Page 147 Eyes distinct, located posterior and medial to the bases of the rhinophores. Anal opening midway between the first and second cerata, 2. e., in the interhepatic space. Genital opening midway on right side between the rhinophore base and the first ceras. Base color translucent white. Rhinophores tipped with opaque white spots, sometimes tinged with red. Red markings sometimes extending from the base of the rhino- phores over the eyes, terminating just before the base of the first cerata; also along each side of the tail. Diverticu- lum brown, rarely green; right branch entering the first ceras only, left branch entering the first left ceras, second left, the second right ceras, thereafter alternating from right to left. Tip of cerata often ringed with a white band. Radula tapering, with 18 teeth. Tooth with a promi- nent, strongly hooked median denticle, flanked by 7 -9 delicate, compressed denticles pointed admedially, 40u wide by 50m high (Figure 12a). Figure 12 Tergipes tergipes b. Anterior view of mandibles a. Dominant tooth c. Lateral view of mandibles Mandibles delicate with a weak hinge. No masticatory process present (Figures 12b, 12c). Habitat: Tergipes tergipes is abundant on hydroids, especially Obelia sp. and Campanularia sp. Egg mass kidney-shaped and about 10 mm long. Egg size 24. Remarks: Marcus (1957) gives an account of the re- productive system as reconstructed from serial sections. His contention that the sperm-producing follicles and the female follicles attach to the gonoduct separately was found to be in contradiction with the condition existing in sections made of 5 Tergipes tergipes specimens during the course of this study. In fact, the many ova-producing fol- licles are clustered about and attach to each of the 4 male follicles. This condition is similar to that found in the genus Eubranchus, perhaps suggesting a close affinity of these 2 genera. Eubranchus olivaceus (O'Donoghue, 1922) Galvina olivacea O'Donoghue, 1922. Trans. Roy. Soc. Canada 14: 158 - 160 Eubranchus olivaceus, O’Donoghue, 1924. Trans. Canad. Inst., Toronto 15: 25 Body elongate, narrow, 8 mm long, tapering to a blunt tail. Back rounded, marked off from the foot by a slight flange. Foot long, narrow, rounded anteriorly, without lateral angles. Head distinct, subglobular, forming 2 lobes anteriorly. Rhinophores long, narrow, lying well anterior to first cerata. Oral tentacles about 4 the length of the rhinophores, cylindrical, set on lobes of head. Anus located in the interhepatic space, just anterior to and slightly lateral to the fourth ceras on the right. Cerata large, 12 - 25 in number, slender, becoming in- flated $ the way up, then tapering to a thin conical point; the first 6 forming 3 pairs oppositely arranged, the re- maining being disposed alternately. The first and third pair more lateral than the second pair. The first right ceras may receive the first branch of the right diverticu- lum, the second and third sharing the second branch or all 3 may share one branch. ‘The first 2 cerata on the left share one extension of the diverticulum, the third left receives a separate ramus, and the fourth left and all the remaining cerata share a third branch of the left diverti- culum in the following pattern: from the fourth left ceras, the diverticulum branches to the fifth right ceras at the base of which a separate branch extends to the fourth right ceras, the branching from the fifth ceras thereafter zigzags left to right, ending after the last ceras in a short, blunt caudal point. Body color translucent white with a slight tinge of green, flecked with orange and white. Oral tentacles and rhinophores tipped with opaque white. Diverticulum pale to olive green. Rhinophores with a ring of orange flecks midway. Cerata with a similar ring at the distal portion of the inflation and again just below the tip. Page 148 THE VELIGER Vol. 14; No. 2 Radula non-tapering, triseriate, with 21-32 rows. Median tooth 25 x 25, with a small median denticle flanked by 5 lateral denticles, the 2 most proximal not pointing admedially, contrary to what O’Donoghue fig- ured in the original description (Figure 13a). Lateral tooth thin, triangular, with a slightly curved tip (Figure 13b). 12 EE [PROS 2 eae Figure 13 Eubranchus olivaceus a. Dominant tooth b. Lateral tooth c. Anterior view of mandibles Mandibles thin, strengthened along the masticatory border by a slight increase in thickness and a row of tiny teeth. Hinge small (Figure 13c). The reproductive system consists of 4 thin-walled sperm follicles to which are attached many female follicles, a condition similar to that found in Tergipes tergipes. The preampullar coelomic gonoduct linking the male follicles is a thin, muscular tubule which enlarges anteriorly to form a low, ciliated cuboidal ampulla surrounded by a thin muscular layer and located in the folds of the female gland. The post-ampullar gonoduct divides shortly after leaving the ampulla into a short oviduct and a longer vas deferens. The oviduct consists of low cuboidal cells which become columnar as it enters the female gland. The vas deferens is a ciliated cuboidal tube surrounded by a thin muscle layer. It bends ventrally, loops around, ascending dorsally to the penis. A separate, hollow, elongated penial bulb consisting of inflated columnar cells with large gran- ular basal nuclei enters the penis at its base. The penis is conical, muscular, with no apparent armament. The receptaculum seminis is of ciliated columnar cells open- ing into the atrium separately. The female gland mass consists of ciliated cuboidal cells and areas of ciliated columnar cells with non-staining apices. Habitat: This species was taken over a period of 3 years feeding on Obelia commisuralis and Campanularia flexuosa, attached to a boat landing. Egg masses resemble those of Tergipes tergipes and were found May through November, probably occurring year around. Egg diameter 16u at the 1 to 4 cell stage and 40 at the veliger stage. Remarks: Since its original description from Vancouver Island, British Columbia, Eubranchus olivaceus has been reported only twice (O’DonocHuE, 1924; STEINBERG, 1963) extending the range to northern Washington. Al- though Goutp (1870) reported this species, he did not recognize it as being a new species, confusing it with Tergipes tergipes and calling it at that time Aeolis des- pecta. His description may fit either species but the pic- ture (his figures 222 - 225) more closely resembles E. oli- vaceus. Aeolidia papillosa (Linnaeus, 1761) Limax papillosus Linnaeus, 1761. Fauna Suecica, ed. 2, p. 508 Doris bodensis Gunnerus, 1770. Skrift. Kobenh. Selsk. 10: 170 Doris vermigera Turton, 1807. Brit. Fauna 1: 132 Eolis cuviert Lamarck, 1819. Hist. Anim. s. Vert. 6: 302 Eolidia zetlandica Forbes & Goodsir, 1839. Athenae- um 681: 647 Eolis rosea Alder & Hancock, 1842. Ann. Mag. Nat. Hist. 9: 34 Eolis obtusalis Alder & Hancock, 1842. Ibid. Aeolis murrayana Macgillivray, 1843. Hist. Moll. Anim. p. 193 Aeolis lesiana Macgillivray, 1843. Hist. Moll. Anim. p. 194 Eolis farinacea Stimpson, 1853. Smithson. Contrib. Knowl. 6: 25 Aeolidia herculea Bergh, 1894. Bull. Mus. Comp. Zool. Harvard 24: 128 Aeolidia papillosa, Chaster et al., 1903. Journ. Conch. 10: 280 Body elongate, up to 60mm in length, broad, back smooth, slightly convex, subtruncate anteriorly, termin- ating in a short, flat tail scarcely extending beyond the cerata. Anterior margin of foot produced into rounded angles. Lateral margins prolonged beyond foot in a thin, trans- lucent line. Vol. 14; No. 2 Anterior tentacles slightly shorter than rhinophores, borne on the rounded outer angle of the head with widened base and pointed, slender tips. Rhinophores simple, conical, blunt, tapering, generally smooth. Cerata flattened, lanceolate (rarely bifurcate) with an- terior surface convex, posterior concave; edges thick and rounded with pointed tips, widened at the base; borne very close together and arranged in about 24 transverse rows, the first 8 - 10 in front of and lateral to the rhino- phores,extending forward to behind the tentacle bases. Posteriorly the dorsal area gradually narrows, the rows meeting behind the heart, posterior to which the entire dorsum is covered by cerata. The oblique rows slant up- ward and posteriorly from the upper margin of the foot. Anal papilla dorso-lateral on the right side between cerata rows 9 and 10. Body color variable: dull rose, tan to dull grey densely mottled with brown and dull yellow flecks. Rhinophores generally a darker shade of the body color bearing similar mottlings. Anterior to rhinophores a large, irregular, cres- centic spot of white or cream with arms prolonged onto the dorsal surface of the tentacles may be present as are smaller spots on the cardiac region. Tentacles with white or dull yellow flecks on the dorsal surface usually confined to the distal half. Cerata marked as body, except at bases. Radula a simple tapering series of 16 teeth 0.8mm in breadth, arched and curved forward, bearing a series 1.4mm F Figure 14 Aeolidia papillosa a. Tooth b. Lateral view of inner side of right mandible c. Lateral view of outer side of right mandible THE VELIGER Page 149 of 40 stout, irregular, lanceolate tipped denticles the 2 median ones forming a divergent angle at their tips (Figure 14a). Mandibles light amber, oval, 3mm wide, 4mm high, with thick hinge region. Anterior portion thick and strong. Masticatory process strong, attached along one edge, free only at the tip (Figures 14 b, 14c). Habitat: Aeolidia papillosa is a common aeolid along the northern coast and may be found intertidally feeding on sea anemones. Egg mass forms a pink, convoluted loose coil about 25 mm in diameter, occasionally larger. There are 2 ova per case, rarely 1, 3, or 4. Fresh ova and case 16 - 20u in diameter, each ovum 8p in diameter. DISTRIBUTION ann ZOOGEOGRAPHY The following is a list of the species found during 1968, and their distribution along the North Atlantic coast of North America. Dates listed in parentheses indicate the presence of eggs during those months. 1. Acanthodoris pilosa: Minas Basin, Nova Scotia; Maine; Connecticut (David Franz, personal commu- nication) ; New Jersey (LovELAND, HENDLER & NEw- KIRK, 1969); (June). 2. Onchidoris fusca: Minas Basin, Nova Scotia (through- out summer) ; Swans Island, Maine (1966) ; Connec- ticut (one large specimen spawning in April, 1969; David Franz, personal communication) . 3. Onchidoris muricata: Northern Nova Scotia to north- ern Cape Cod (June and July); Connecticut (sub- tidal, David Franz, personal communication ). 4. Ancula gibbosa: Northern Nova Scotia; Maine; Con- necticut. 5. Polycera dubia: Minas Basin and southern tip of Nova Scotia to northern Cape Cod; Connecticut. 6. Dendronotus frondosus: Abundant along the entire northern coastline (young individuals 2 - 3 mm abund- ant along this area in June); Connecticut (David Franz, personal communication) ; New Jersey (Love- LAND, HENDLER & NEWKIRK, 1969). 7. Doto coronata: Along entire coastline (May - July) ; Connecticut (David Franz, personal communication) ; New Jersey (Franz, 1968; LoveLanp, HENDLER & Newkirk, 1969). 8. Facelina bostoniensis: Minas Basin? (1966 - 1967) ; Walpole, Maine. Page 150 THE VELIGER Vol. 14; No. 2 9. Coryphella verrucosa: Common along whole northern coast (April - July); may be submergent south of Cape Cod, Massachusetts. 10. Coryphella stellata: Minas Basin, Nova Scotia. 11. Cuthona concinna: Southern tip of Nova Scotia; Black Rock, Nova Scotia; Swans Island, Maine. 12. Tergipes tergipes: Along the entire coast (June - No- vember) ; Connecticut (David Franz, personal com- munication) ; New Jersey (FRANz, 1968; LovELAND, HENpLER & NeEwxirK, 1969). 13. Eubranchus olivaceus: Swans Island, Baileys Island, Maine (May - November) ; other known records from British Columbia and Washington. 14. Aeolidia papillosa: Common along northern coast- line; Connecticut (David Franz, personal communica- tion) ; New Jersey (FRANz, 1968; LovELanp, HENp- LER & NEWkirK, 1969). Distribution: The general distribution along the north- western coast of the Atlantic is summarized in Table 1. The species inhabiting this coast represent members of a boreo-arctic and boreal fauna. A boreo-arctic species is reproductively a cold stenotherm, but is vegetatively eury- thermal extending well into the boreal region where it Table 1 Distribution of Nudibranchs on the North Atlantic Coast of North America pee ites > a 10 oo Fa g fQ eo) 3 SS 8 u : So S| [en o Species Ba &§ 2 | < “AS GO MB & & Acanthodoris pilosa x x x x B Onchidoris fusca x x B-A Onchidoris muricata x x B Ancula gibbosa x x B Polycera dubia x x B Dendronotus frondosus x x x B-A Doto coronata x x x B Facelina bostoniensis x B Coryphella stellata x B Coryphella verrucosa x B-A Tergipes tergipes x x x B Eubranchus olivaceus x B Cuthona concinna x B Aeolidia papillosa x x x x B-A « B-A — Boreo-Arctic species; B - Boreal species occurs in the littoral zone, reproducing in winter and early spring (= the arctic-boreolittoral of LeMcHE, 1941a). A boreal species is vegetatively eurythermal, but is reproductively a warm stenotherm penetrating north to an extent dependent upon its ability to develop fast enough during a short summer (= boreal-arctolittoral of Lemcue, 1941a). As Exman (1953) indicated, the limits of the Ameri- can boreal marine region are difficult to define since the boundaries change position according to the season and ocean currents. The waters of the Gulf of Maine and eastern coast of Nova Scotia are strongly influenced by the influx of the cold Labrador Current which acts as a wedge between the Gulf Stream and the coastline cooling the coastal waters north of Cape Cod, Massachusetts. The waters south of Cape Cod are more strongly affected by the Gulf Stream and, although Cape Cod is no longer recognized as the southern boundary of the arctic zoo- geographical region (EKMAN, 1953), it does form a bar- rier to so ubiquitous a northern form as Coryphella ver- rucosa which occurs abundantly just on the north side at Manomet (Station 1), but cannot be found intertidally south of the Cape, although it may possibly become sub- mergent. The same situation may apply to Facelina bostoniensis and Eubranchus olivaceus, which may need colder waters for spawning than those found south of Cape Cod. Eu- branchus olivaceus occurs on the Pacific coast in waters which are constant about 10° C, a condition also found in the Gulf of Maine. However, this species may have a limited seasonal occurrence south of the Cape during the winter and early spring when water temperatures in Con- necticut are about 10° C. This is the case with the boreo- arctic species, Onchidoris fusca, which may extend its range south of Cape Cod during the cold waters of early spring (April), but is never found there in the later spring or summer (David Franz, personal communication). As indicated by Franz (1968) and LoveLaAnp, HEND- LER & Newkirk (1969), the nudibranch fauna of south- ern New England and New Jersey represents a southern extension of the northern New England fauna. Of the 14 species, 11 extend into Connecticut, 5 as far south as New Jersey and 2 into Maryland (Marcus, 1961). Franz (1968) suggests that the paucity of New Jersey nudi- branchs is due to the change from a rocky shore of New England to the sandy-muddy coast of New Jersey. How- ever, as Loveland et al. indicate, increasing numbers of man-made jetties and floating wharves provide suitable substrates for nudibranchs and, as collecting intensity in- creases, more New England forms may be found. Vol. 14; No. 2 THE VELIGER Ravemlall Zoogeographical Considerations: Eleven of the 14 spe- cies are amphiatlantic, 7. e., are also members of the Euro- pean fauna (Table 2). Of the remaining 3, Coryphella stellata and Facellina bostoniensis are endemic to the northwestern Atlantic and Eubranchus olivaceus is repor- ted only from the Pacific coast of North America (O’Do- NOGHUE, 1922, 1924; STEINBERG, 1963). Table 2 Distribution of Nudibranchs of the North Atlantic Sea 3 35 3§ « gs fe ! as ga 8 Species zg SU eg 0A AA Q Acanthodoris pilosa x B Onchidoris fusca x B-A Onchidoris muricata x B Ancula gibbosa x B Polycera dubia x B Dendronotus frondosus x B-A Doto coronata x B Facelina bostoniensis Northwestern Atlantic Endemic Coryphella stellata Northwestern Atlantic Endemic Coryphella verrucosa x B-A Cuthona concinna x B Tergipes tergipes x B Eubranchus olivaceus Also on North Pacific Coast Aeolidia papillosa x B-A 2 B-A — Boreo-Arctic species; B -— Boreal species To explain the distribution of amphiatlantic species it is necessary to understand some of the geographical and hydrographical conditions existing in the North Atlantic. The possibility of active or passive larval transport is much greater in the most northern Atlantic than further south since the distance between Europe and North America is broken up by islands and ridges between Scotland, the Faros, Iceland and Greenland. This fact, in combination with the influence of the Gulf Stream, which warms the waters off the western and southern coasts of Greenland, south, west and northwest Iceland, and the Farés to Lo- foten, Norway, serves to link many of the boreo-arctic and boreal species to the two larger landmasses. However, cold polar currents along the east coast of Greenland and northeastern Iceland create arctic conditions and may serve as barriers to the distribution of some boreal forms more stenothermal than others. Of the 4 boreo-arctic species, only Dendronotus fron- dosus and Coryphella verrucosa show a continuous distri- bution across the island chain (Lemcue, 1941a, 1941b). Onchidoris fusca and Aeolidia papillosa are continuous except at eastern Greenland, but this presents no barrier since they occur along the warmer southern and western Greenland coasts. The boreal species Polycera dubia and Ancula gibbosa show similar distributions. The distribution of the remaining amphiatlantic species is discontinuous despite the existence of boreal conditions at each point in the chain. Acanthodoris pilosa, Doto coronata, and Tergipes tergipes (this record questionable according to LemcHeE, 1938), although occurring in Ice- land, are not found in Greenland. Onchidoris muricata and Cuthona concinna are recorded only from northern Europe. These species may be a bit more stenothermal than the others and may represent relict populations isolated from each other during the cooling climatic conditions follow- ing the post-glacial hypothermal period at the close of the Pleistocene. An alternative explanation for the distribution of am- phiatlantic species may be the transport of larvae across the Atlantic by currents. Although THorson (1961) im- plies that trans-Atlantic larval transport is a rare phen- omenon, SCHELTEMA (1966) indicates that it may not be nearly so uncommon among many specially adapted larval forms. However, the life cycles and length of pelag- ic larval existence, where it occurs in the nudibranchs, are not well enough understood as yet to warrant application of this theory. SUMMARY 1. The species Acanthodoris pilosa, Onchidoris fusca, O. muricata, Ancula gibbosa, Dendronotus frondosus, Doto coronata, Facelina bostoniensis, Coryphella verrucosa, C. stellata, Cuthona concinna, Tergipes tergipes, Eubran- chus olivaceus, Polycera dubia and Aeolidia papillosa were collected along the coast of northern New England and Nova Scotia during 1968. 2. This constitutes the first report of Coryphella stellata since its original description in 1853. 3. Of these species, all but 3 (Coryphella verrucosa, Fa- celina bostoniensis and Eubranchus olivaceus) extend at least into Connecticut, but only Acanthodoris pilosa, Dendronotus frondosus, Doto coronata, Tergipes tergipes extend into New Jersey. 4. Two of the species, Facellina bostoniensis and Cory- phella stellata, are northwestern Atlantic endemic species Page 152 and Eubranchus olivaceus is reported from the north- eastern Pacific coast. The remaining species are amphi- Atlantic. 5. Of the amphiatlantic boreal species, all but Acantho- doris pilosa, Onchidoris muricata, Doto coronata, Cutho- na concinna and Tergipes tergipes show continuous distri- bution across the northern islands of Greenland, Iceland, the Farés, and Norway. 6. The discontinuous distribution of the remaining spe- cies may be explained by the extinction of connecting populations during the cooling period following the post- glacial warm period. ACKNOWLEDGMENTS This paper (with revisions) forms part of a thesis submitted to the University of Connecticut. I gratefully acknowledge my advisor David Franz for his encourage- ment and constructive criticism of the paper. I am also indebted to Drs. Carl Schaefer and Sung Yen Feng for their help. Thanks also go to Mrs. Marie Abbott for translation of the German papers and to Miss Mary Hubbard for her invaluable aid with the illustrations. Literature Cited Bercu, Lupwic Sopuus RupDOLF 1875. _ Beitrage zur Kenntni® der Aeolidiaden II. Ver- handl. Zool. Bot. Gesell. Wien 24: 395 - 416 1877. Beitrage zur Kennti8 der Aeolidiaden IV. Ver- handl. Zool. Bot. Gesell. Wien 26: 737 - 764 1878. __ Beitrage zur Kenntni8 der Aeolidiaden V. Ver- handl. Zool. Bot. Gesell. Wien 27: 809 - 840 1886. _ Beitrage zur Kenntni8 der Aeolidiaden VIII. Ver- handl. Zool. Bot. Gesell. Wien 35: 1 - 60 1891. | Die cladohepatischen Nudibranchien. (Syst.) 5: 1-75 EKMAN, SVEN 1953. Zoogeography of the Sea. London, v+417 pp. Franz, Davin R. 1968. Occurrence and distribution of New Jersey Opistho- branchia. The Nautilus 82 (1): 7-12 (July 1968) Gou.p, Aucustus AppISON 1870. Invertebrata of Massachusetts. W. G. Binney (ed.), Wright & Potter, Boston. v+524 pp.; 11 plts.; 755 figs. La RocguE, AURELE 1953. Catalogue of Recent Mollusca of Canada. Nat. Mus. Canada Bull. No. 129: ix+406 pp. LemcHE, HENNING 1935. On some nudibranchiate gastropods from the northern Atlantic. Dansk. Nat. Foren. Copenhagen, Vidensk. Med- del. 99: 131 - 148 Zool. Jahrb. Sedgewick & Jackson, THE VELIGER Vol. 14; No. 2 LemcuHeE, HENNING (continued) 1938. Gastropoda Opisthobranchiata. In: Zoology of Ice- land 4: 1-54 1941a. Gastropoda Opisthobranchiata. In: Zoology of East Greenland. Meddel. Groenl. 12: 1 - 50 1941b. Gastropoda Opisthobranchiata. In: The Godthaab Expedition. Meddel. Groenl. 80: 1 - 65 LovELanp, Rosert E., Gorpon HENDLER & Gary NEWKIRK 1969. New records of nudibranchs from New Jersey. The Veliger 11 (4): 418-420 (1 April 1969) Marcus, ERNsT 1957. On Opisthobranchia from Brazil II. Soc. London 43: 309 - 486; figs. 1 - 246 1961. | Opisthobranchia from North Carolina. Elisha Mitchell Sci. Soc. 77 (2): 141 - 151 Moore, Greorce M. 1950. Progress report on investigations of the Nudibranchiata of New England. Biol. Bull. 99 (2): 352 - 353 1964. Shell-less Opisthobranchia, pp. 153 - 164; 27 figs. In: R. I. Smiru (ed.) Keys to marine invertebrates of the Woods Hole Region. Contr. 11, System.-Ecol. Program, Marine Biol. Labor., Woods Hole, Mass., i+ 208 pp.; 28 plts. Opuner, Nits HJALMAR 1939. | Opisthobranchiate mollusca from the western and north- ern coasts of Norway. Kgl. Norska Vidensk. Selsk. Skr. 1; 1 - 93; 59 text figs. (20 February 1939) O'DONOGHUE, CHARLES HENRY 1922. Notes on the nudibranchiate Mollusca from the Van- couver Island region. Trans. Roy. Soc. Canad. Inst. 14 (12): 123 - 167 1924. | Notes on the nudibranchiate Mollusca from the Van- Trans. Roy. Soc. Canad. Inst. 15 Journ. Linn. Journ. couver Island region. (33): 1-33 RosiLuiarD, Gorpon A. 1970. The systematics and some aspects of the ecology of the genus Dendronotus. The Veliger 12 (4): 433 - 479; plts. 63, 64; 24 text figs. (1 April 1970) ScHELTEMA, Rupotr S. 1966. Evidence for the trans-Atlantic transport of gastropod larvae belonging to the genus C'ymatium. Deep-Sea Res. 13: 83 - 95 STEINBERG, JOAN EmILy 1963. Notes on the opisthobranchs of the West Coast of North America - IV. A distributional list of opisthobranchs from Point Conception to Vancouver Island. The Veliger 6 (2) : 68 to 73 (1 October 1963) Stimpson, WILLIAM 1853. | Synopsis of the marine Invertebrata of Grand Manan, or the region around the Bay of Fundy, New Brunswick. Smithson. Contrib. to Knowledge 6: 1 - 67; plts. 1-3 Tuorson, GUNNAR 1961. Length of pelagic larval life in marine bottom inverte- brates as related to larval transport by ocean currents. In: Oceanography, M. Sears, ed.; publ. 67 AAAS: 455 - 474 VERRILL, ADDISON EMERY 1873. | Report upon the invertebrate animals of Vineyard Sound and the adjacent waters, with an account of the physical characteristics of the region. Reprt. U.S. Fish Comm. on the condition of the sea fisheries of the South Coast of New England in 1871 and 1872: 295-778 Vol. 14; No. 2 THE VELIGER Page 153 Description of Doto (Doto) fragilis nipponensis subspec. nov. from Sagami Bay, Japan (Nudibranchia : Dendronotoidea : Dotoidae) KIKUTARO BABA (1 Text figure) Doto (Doto) fragilis nipponensis Baba, subspec. nov. (Japanese name: Ibo-matsukasa-umiush1) (Figure 1) Holotype: Collected by his Majesty, the Emperor of Japan from the depth of 20 meters off Hayama, Sagami Bay, on 26" July, 1952, and designated as Det. no. 657. Preserved, about 15mm in length. Margin of rhino- phorial sheaths lobated. There are 7 pairs of branchial papillae standing on the back margins. ‘The largest pa- pillae consist of 5 circlets of tubercles, with 3-4 of these latter in each circlet. The tubercles are considerably elon- gated. A dendriform gill fold is present on each branchial papilla. In the present form it is remarkable that there is a series of bluntly conical tubercles on the median line of the back and on each side of the body. In colour the preserved animal is uniformly ashy yellow; the papillar tubercles are not marked with apical spots of melanin black. The radular formula is about 83 < 0-1:0. Each tooth is flanked by 4 to 5 denticles. Paratype: Collected together with the holotype. Length about 10 mm. The various diagnoses of the paratype are approximately as given for the holotype. The mouth part was not opened. Remarks: Evidently the form represented by both spe- cimens described above belongs to group III of the key by OpHneEr (1936, pp. 1119 - 1121) for the classification of the species of Doto for having no black spots on the top of the papillar tubercles, and this is conjectured to be closely related with D. (D.) fragilis (Forbes, 1838) by the formation of tubercles arranged on the mid-dorsal line and on the sides (see ALDER & Hancock, 1851, prt. ' Present address: Shigigaoka 35, Minami 1t1-jyo, Sango-cho, Ikoma-gun, Nara-ken, Japan 5, fam. 3, plt. 5, D. fragilis; and Marcus & Marcus, 1969, pp. 27 - 29; figs. 38 - 39, D. fragilis umia). Actually D. (D.) fragilis is a deep-water form (see ALDER & HAN- cock, loc. cit.; LEMcHE, 1938, p. 16) which is distributed in the North Atlantic Ocean and the Mediterranean Sea. As the Japanese specimens of Doto in question differ from the typical members of D. (D.) fragilis (see also Kress, 1968, pp. 246 - 247; plt. 2, fig. 2) in some points as shown below, they are here regarded as forming the type series of a new subspecies of that species, namely Doto (Doto) fragilis nipponensis. I. Doto (Doto) fragilis fragilis: 1. Body large, 25-40 mm long 2. Branchial papillae 9 - 10 pairs, each papilla with 7-9 circlets of obtusely pointed tubercles which are capable of considerable elongation II. Doto (Doto) fragilis nipponensis : 1. Body small, 10 - 15 mm long 2. Branchial papillae 7 pairs, each papilla with 4 - 5 circlets of elongated conical tubercles In Doto (Doto) fragilis umia Marcus & Marcus, 1969 from Greenland it is said that the tubercles on the dorsal midline are elevated in the form of high papillae. Doto (D.) pinnatifida (Montagu, 1804) from British waters is another species which has tubercles on the back and sides but which bears black markings on the top of the papillar tubercles (see Odhner’s key, group I, subgroup A). Literature Cited ALDER, JosHuUA, & ALBANY Hancock 1844-1855. A monograph of the British nudibranchiate Mollusca, with figures of all the species. London. Ray Soc. prts. 1 - 7: 438 pp.; 84 plts. Page 154 THE VELIGER Vol. 14; No. 2 Figure 1 Doto (Doto) fragilis nipponensis Baba, subspec. nov. (Holotype) A: Preserved animal from right side; length 15 mm a — anus b — rhinophore c — genital orifice Kress, ANNETRUDI 1968. Untersuchungen zur Histologie, Autotomie und Regene- ration dreier Doto Arten, Doto coronata, D. pinnatifida, D. fragilis (Gastropoda, Opisthobranchiata) . Rev. Suisse de Zool. 75 (2): 235-303; plts. 1-4; 29 text figs. LemcuHe, HENNING 1938. Gastropoda Opisthobranchiata. In: The Zoology of Iceland 4 (61): 1-54; figs. 1-3 B to C: A branchial papilla from the upper and lateral surfaces a — gill fold D: A radular tooth (X 620) Marcus, EveLinE pu Bots REyMonp & Ernst Marcus 1969. Opisthobranchian and lamellarian gastropods collected by the “Vema.” Amer. Mus. Novitates 2368: 1 - 33; text figs. 1 - 39 Opune_er, Nits HjaLmar 1936. | Nudibranchia Dendronotacea. A revision of the System. Mélanges Paul Pelseneer. Mém. Mus. Roy. d’Hist. Nat. de Belgique, Ser. II, Fasc. 3: 1057-1128; 1 plt.; text figs. 1-47. Vol. 14; No. 2 THE VELIGER Page 155 The Biology and a Redescription of the Opisthobranch Mollusk Hermaea cruciata Gould, from Chesapeake Bay ' (Sacoglossa : Hermaeidae) BY ROSALIE M. VOGEL Natural Resources Institute Chesapeake Biological Laboratory, Solomons, Maryland 20688 (1 Plate; 2 Text figures) Our STUDIES OF THE BIOLOGY of sea nettles have required that dredge samples be taken at regular intervals. Part of our research was directed toward the discovery of * Contribution No. 461, Natural Resources Institute of the Uni- versity of Maryland Hermaea cruciata C — Ceras E — Eye F — foot H — heart A: dorsal view B: three-quarters view, showing reproductive L—liver diverticulum S — spots R - reproductive openings opening Rh — rhinophore Page 156 THE VELIGER Vol. 14; No. 2 possible nudibranch predators on scyphozoan polyps. In addition, we recorded information on other nudibranchs in an attempt to better understand the biological relation- ships between jellyfish and nudibranchs. During these investigations, an adult opisthobranch mollusk was taken in October 1968 from Deal Island, Maryland (sal. 16.9%, temp. 19.5° C). (Deposited in the Division of Mollusks, U.S. National Museum, Washington, D. C., USNM no. 577625). The animal, 10mm long, was found among strands of the red alga, Agardhiella sp., and detritus in the dredge sample. The animal is identified as Hermaea cruciata Gould, 1870 (Figures 1 and 2). Goutp (1870), VERRILL (1873), and JouNson (1934) based their record of occurrence on a drawing by A. Agassiz from Naushon Island, Massachusetts, September 1863. Franz (1970: 176) reports on a specimen from Chesapeake Bay, dis- covered by A. Marsh (Virginia Institute of Marine Sci- ence). This, then, is the third Hermaea cruciata on record collected on the east coast of North America. This note discusses my observations of the living animal, its egg mass, veligers, and a redescription of the living animal. A description and drawing of the radula are given. The body is aeolidiform, being long and slender with cerata projecting from its back. The foot is narrow (about one-half as wide as the body). The anterior portion of the foot projects laterally to form pointed palplike structures. The tail is one-eighth the length of the entire animal and is long and narrow, almost filiform. The back of the animal is high in the cardiac region; anteriorly, the body slopes to the head. The cardiac bulb stops abruptly, pos- teriorly, leaving the rest of the back slightly flattened to the top of the tail. The back shows paired lateral regions of liver diverticula, the anterior ends of which are joined. They extend from a region just anterior to the heart, slightly lateral to it, and well into the tail. The head is terminal. The mouth is ventral and encom- passed by fleshy lips. The rhinophores are the same length as the large cerata (approximately 3mm). They are folded longitudinally in a manner characteristic for the genus Hermaea. The more dorsal fold of the rhinophore is longer than the ventral fold. There is brown pigment, the color of the liver, on the dorsal side of each rhino- phore. The eyes are located just posterior to the rhino- phores. They appear as distinct black spots surrounded by clear areas. The cerata are located on the back in paired rows of 2 or 3. The dorsolateral cerata are the longest and best developed. They are cylindrical, approximately 3 mm in length, and contain a very thin liver diverticulum. The liver divides at the distal end of each ceras, twice, thrice, or 4 times, to make 4 or 5 distinct branches. One branch Figure 3 Hermaea cructiata B: radular tooth (length 0.108 mm) A: ege mass C: penis is always terminal in the center with the other branches radiating into each point of the ceras below the terminal tip. This arrangement resembles a crown. The more lateral cerata have from 1 to 3 points, and sometimes the liver extends only in the center point. There are 3 dorsal cerata situated just anterior to the heart. The anal opening, not clearly seen, appeared to be anterior to the first ceras. The reproductive openings are on the right side, posterior to the rhinophore. The penis is armed with hooks (Figure 3C). There are no jaws. The radula has 17 teeth with 10 on the upper portion of the ribbon and 7 on the lower part. Tue VELIGER, Vol. 14, No. 2 [VocEL] Figure 2 Figure 2 Photograph of dorsal view of a living Hermaea cruciata Vol. 14; No. 2 THE VELIGER Page 157 The edge of each tooth is smooth and the base is one-third the length of the tooth (Figure 3B). The body was cream-colored with a greenish cast. The liver diverticula were an amber-brown. White wartlike spots covered the entire animal. The number of white spots on each ceras was proportional to the size of the ceras. There is a concentration of the spots on the tips of each ceras causing the entire end with all its points to be white. The animal crawled around the bowl and also on the surface film. It did not seem to be attracted to light. When it was disturbed, it curled in a circle, usually moving its head in a clockwise position until it looked like a ball of cerata. The cerata contracted and expanded at various times. The liver diverticula in the cerata did not seem to pulsate like the liver diverticula do in Cratena pilata (Gould, 1870) under certain conditions. The animal was not seen to feed in captivity. The second night the animal was in the laboratory, it laid a comma-shaped egg mass (Figure 3A) which con- tained spirally arranged eggs, quite similar to those of Staiger fuscatus (Gould, 1870). The egg mass is more firm than that of S. fuscatus, and was fastened at its center to the side of the glass container. The eggs in one end were large, well developed, and very numerous when compared with those at the other end. The small ones did not develop past the first few stages of cleavage. Only one egg was found in each egg capsule. The egg capsules were approx- imately 150 in diameter with the eggs being approxi- mately 100u. Veligers were present in the eggs at 3 days. They moved slowly for another day and hatched before the morning of the fifth day. REMARKS Hermaea cruciata is similar to both H. cotrala Marcus, 1955, and H. hillae Marcus & Marcus, 1967, but differs from them in a number of details. In H. cruciata, the branches in the liver diverticula occur only near the ends of the cerata and not in the entire length of the cerata, as they do in the other 2 species. Hermaea cruciata also has brown pigment like that of the liver diverticula on the rhinophores. This pigment is not present in either H. coi- rala or H. hillae. The penis of H. cruciata is armed with 3 hooks, whereas those of H. coirala and H. hillae are un- armored. The radular teeth in H. cruciata are smooth- edged and similar to those of H. coirala, except they are twice as long and do not possess the basal hooks of H. cotrala, The radular teeth of H. hillae have a serrated edge. ACKNOWLEDGMENTS I am pleased to thank Mrs. Eveline Marcus, of Sao Paulo, Brazil, for confirming the identification; and Dr. David R. Franz, of the University of Connecticut, for his valu- able suggestions; and the following staff members of Ches- apeake Biological Laboratory: Dr. Leonard P. Schultz, for his stimulation and help in writing this note; Mr. David G. Cargo, for collecting the mollusk; Mrs. Alice Jane Mansueti, for the drawings; and Mr. Michael J. Reber, for the photograph. This research was supported in part by the National Marine Fisheries Service of the Department of Commerce and the State of Maryland, Fish and Wildlife Administra- tion, Contract No. 14-17-0003-571, under Public Law No. 89-720 of the Jellyfish Act. Literature Cited Franz, Davin R. 1970. Zoogeography of northwest Atlantic opisthobranch mol- luscs. Marine Biol. 7: 171 - 180; 5 text figs. (9 July 1970) GouLtp, Aucustus ADDISON 1870. | Report on the Invertebrata of Massachusetts. 24 ed. vi+524 pp.; 12 col. plts.; wood cuts. Boston JoHNson, Cuaries W. 1934. List of marine mollusca of the Atlantic Coast from Lab- rador to Texas. Proc. Boston Soc. Nat. Hist. 40 (1): 1 - 204 (July 1934) Marcus, ERNST 1955. Opisthobranchia from Brazil. Bol. Fac. Fil. Univ. Sao Paulo, Zoologia 20; 89 - 200; plts. 1-30 Marcus, EvaALINE & Ernst Marcus 1967. | American opisthobranch mollusks. Studies in tropical Oceanography no. 6. Inst. Marine Sci., Univ. Miami, Florida; viiit 256 pp.; 1 plt.; 155+ 95 text figs. | (December) VERRILL, AppiIson Emory 1873. | Report upon the invertebrate animals of Vineyard Sound and adjacent waters, with an account of the physical characters of the region. Rept. U. S. Comm. Fish and Fisheries, prt. 1: 295 - 778; plts. 1 - 39 Page 158 THE VELIGER Vol. 14; No. 2 Studies on the Food of Nudibranchs JAMES W. McBETH Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92037 INTRODUCTION ALTHOUGH MUCH INFORMATION is available on the bio- logy of many eastern Pacific nudibranchs, few studies have been directed toward their feeding habits. In contrast to this situation, considerable information is available on the diets and feeding behavior of a large portion of the nudibranchiate fauna of Europe (Forrest, 1953; Gra- HAM, 1955; SwENNEN, 1961; Mutter, 1961, 1965; TuHompson, 1964) and of the central and west-Pacific (Youne, 1966, 1967). As part of a primary study concerned with the colored pigments of nudibranchs (McBetu, 1970), a prelimi- nary examination was made on the diets of 6 species. The following criteria were used in establishing the food of each species: 1) field observations of the nudibranchs in association with the potential food organisms; 2) lab- oratory observations of feeding behavior; and 3) occur- rence of recognizable food particles in the alimentary tracts and feces of the nudibranchs. All of the species studied were collected from the San Diego area. RESULTS Hypselodoris californiensis (Bergh, 1879) Many dorid nudibranchs studied to date have been found to be rasping sponge-feeders (GraHaAM, 1955; AsouL-E1ra, 1959; SwENNEN, 1961; Mitier, 1961, 1965; TuHompson, 1964; Youne, 1966, 1967). The diet of Hyp- selodoris californiensis was also found to consist of spon- ges, as demonstrated by field and laboratory observations (see Table 1). Spicules of the particular sponges were often isolated from the feces and alimentary tracts of freshly collected specimens. Individuals of H. californi- ensis were observed and collected from waters ranging from less than one foot to more than 60 feet in depth. Anisodoris nobilis (MacFarland, 1905) Anisodoris nobilis was also found to be a rasping sponge- feeder. Its diet appears to consist of a variety of sponges, Table 1 Diets of Nudibranchs from San Diego, California Nudibranch_ species Diet Hypselodoris californiensis Sponges Stelletta estrella de Laubenfels, 1930 (1% 3) Haliclona sp. (*»?»3) Anisodoris nobilis Sponges Myzxilla agennes de Laubenfels, 1930 (12-3) Paresperella psila de Laubenfels, 1930 (3) Zygerphe hyaloderma de Laubenfels, 1932 (3) Mycale macginitiei de Laubenfels, 1930 (3) Prianos sp. (3) 4 unidentified species (3) Hopkinsia rosacea Bryozoan Eurystomella bilabiata Hincks, 1884 (* 2) Triopha carpenteri Bryozoans Scrupocellaria diegensis Robertson, 1905 (* 7-3) Crisia serrulata Osborn, 1953 (* 2)3) Cellaria mandibulata Hincks, 1882 (12:3) Dendrodoris fulva Sponges Clione celata Grant, 1827 (1?) Ficulina suberea lata Lambe, 1892 (*:?:3) Acarnus erithacus de Laubenfels, 1927 (12:3) Suberites sp. (?) Flabellinopsis todinea Hydroid Eudendrium ramosum Linnaeus, 1758 (* 7) (*) Nudibranch associated with prey in the field (?) Nudibranch observed feeding on prey in the laboratory (3) Prey isolated from alimentary tract of nudibranch although it was most often found associated with Myxilla agennes in the field. Moreover, the spicules of this sponge occurred most often in the alimentary tracts of freshly collected specimens of Anisodoris. The other sponges con- sumed by this nudibranch were ascertained exclusively Vol. 14; No. 2 from gut analyses (see Table 1). All specimens of A. nobi- lis were observed and collected from waters ranging from 60 to 110 feet in depth. Hopkinsia rosacea MacFarland, 1905 The results of this study indicate that Hopkinsia rosa- cea feeds exclusively on the pink encrusting bryozoan, Eurystomella bilabiata. It was often observed in associa- tion with this bryozoan in the field, and consumed it readily in the laboratory. Its feeding behavior closely re- sembles that described for other suctorial dorid nudi- branchs which also consume encrusting bryozoans (THompson, 1958; Morse, 1967; McBetu, 1968). The nudibranch first rasps a hole in the frontal membrane of the zooid via radular action. The soft parts of the ecto- proct are then sucked out as a result of buccal bulb contractions. This feeding response is also similar to that described for those suctorial nudibranchs which consume barnacles (BARNES & PowELL, 1954), ascidians (FoRREST, 1953) and arborescent bryozoans (Mirier, 1965). All specimens of Hopkinsia rosacea studied in this work were collected intertidally. Triopha carpenteri (Stearns, 1873) The diet of Triopha carpenteri was found to consist of 3 species of arborescent bryozoans. Gut analyses of over 100 freshly collected individuals invariably yielded the partly digested fragments of Scrupocellaria diegensis, Crisia serrulata, and Cellaria mandibulata, listed in order of decreasing abundance. Individuals of Triopha were often observed crawling on these closely-associated bryo- zoans in the field, and consumed them readily in the laboratory. Specimens of Triopha were collected from depths of 60 to 100 feet of water. Many other polycerid nudibranchs have been reported to consume arborescent bryozoans (GraHAM, 1955; Mi.- LER, 1961), and the feeding behavior of Triopha carpen- teri seems to be quite similar to that described for Poly- cera sp. (Miter, 1965). Branch segments of the bryozoan colony are broken off and ingested by the combination of radular action, grasping jaws, and body contractions. As the engulfed fragments pass through the alimentary tract of the nudibranch, the soft parts are digested away, leaving the intact, identifiable branch segments. Dendrodoris fulua MacFarland, 1905 by The diet of the “porostomes,” a group of dorid nudi- branchs lacking radulae and jaws, has been difficult to ascertain. Evior (1908) mentioned that specimens of Dendrodoris nigra Stimpson, 1855, from the Suez area, THE VELIGER Page 159 were found “in the cavities of a red sponge which they probably eat.” Pruvot-For (1954) suggested that the porostomes were probably reduced to ingesting ooze (slime and mud) for nourishment because of their lack of “hard parts.” Two relatively recent reports, however, have established the fact that members of the genus Dendrodoris can feed on sponges. GuisEtin (1964) reported that specimens of Dendrodoris albopunctata (Cooper, 1863) consumed a variety of sponges as demonstrated by field observations and gut analyses. He observed that during feeding, a tubular structure was everted from the mouth. YouNG (1966), studying the feeding behavior of D. nigra on the sponge Halichondria dura Lindgren, 1894, hypothesized that when the buccal bulb is protracted during feeding, the ptyaline gland secretes a substance through the mouth which breaks down the spongin fibers of the prey. The resulting liquid, containing mesenchyme cells and spicules, is then sucked into the mouth by the action of the specialized buccal apparatus. Specimens of Dendrodoris fulva studied in this work were collected from waters 70 to 110 feet in depth. They were often observed with their buccal bulbs everted while humped over sponges, presumably in a feeding response. The nudibranchs were observed on a variety of sponges, both in the field and in the laboratory. In only one instance, however, were sponge spicules actually recovered from the alimentary tract (see Table 1). It is interesting to note in this regard, that both GHISELIN (op. cit.) and Younc (op. cit.) were able to isolate sponge spicules from the intestinal tracts of many specimens, whereas GOHAR & SotimMan (1967) could find “no identifiable food par- ticles in the alimentary canal” of D. fumata (Ruppell Leuckart, 1828) from the Red Sea. Flabellinopsis iodinea (Cooper, 1862) The diet of Flabellinopsis iodinea was found to consist entirely of the hydroid Eudendrium ramosum. A large number of other aeolid nudibranchs have also been re- ported to consume hydroids (McMitran, 1942; Pruvor- For, 1954; Grawam, 1955; SwenneNn, 1961; MILter, 1961, 1965; Russet, 1964; THompson, 1964). Individuals of Flabellinopsis were observed crawling on colonies of Eudendrium in waters from less than one foot in depth to more than 100 feet. The feeding behavior was observed in the laboratory. When the nudibranch comes in contact with a hydranth, the lips manipulate it into a suitable position for the jaws to grasp. The hydranth is torn from the stalk as a result of 3 or 4 violent contrac- tions of the body. The detached hydranth is then drawn into the mouth via radular action. Page 160 THE VELIGER Vol. 14; No. 2 DISCUSSION Some nudibranchs have been found to be very selective in their choice of food organisms (STEHOUWER, 1952; BraaMs & GEELEN, 1954; SwENNEN, 1961; Cook, 1962; TxHompson, 1962).THompson (1964) states that all spe- cies of nudibranchs “may have a single preferred food- organism, but in the absence of this it will attack other prey.” The sponge-consuming nudibranchs studied in this work do not appear to be species-specific in their choice of food. The results reported herein suggest that Hypselo- doris californiensis, Anisodoris nobilis and Dendrodoris fulva all feed on a variety of sponges. Further studies are needed, however, before any degrees of preference can be established. Hopkinsia rosacea does appear to be species-specific in its choice of food. It was never observed in association with any food organism other than the bryozoan, Eury- stomella bilabiata. The discovery of relatively large depos- its of the unique carotenoid, hopkinsiaxanthin, in the integuments of both Hopkinsia and Eurystomella (Mc- BetH, 1970) tends to confirm the results of this food study. Future studies on the feeding habits of Hopkinsia rosacea specimens collected from other localities along the coast would be of great interest in ascertaining the degree of dependency of the nudibranch’s distribution on that of the prey. Triopha carpenteri and Flabellinopsis iodinea also ap- pear to be rather specific in their feeding habits. Compar- ative pigment analyses of the nudibranchs and their respective prey tend to strengthen this supposition (Mc- Betu, 1970). Before any final conclusion can be drawn, however, more detailed food-preference studies are needed, including comparisons of distributional patterns. ACKNOWLEDGMENTS I would like to thank Dr. John Soule for identifying the bryozoans mentioned in this work. I also thank Dennis Lees for his help in identifying the hydroid. This study was made possible by the National Science Foundation through a grant to Professor Denis L. Fox, Scripps Institution of Oceanography. Literature Cited Apou.t-E1La, Ipranim AHMED 1959. On the food of nudibranchs. Biol. Bull. 117: 439 - 442 Barnes, Harotp « H. T. PowELt 1954. Onchidoris fusca (Miller), a predator of barnacles. Journ. Animal Ecol. 23: 361 - 363 Braams, W. G. «& HANNIE FE M. GEELEN 1953. The preference of some nudibranch eolids for certain coelenterates. Arch. Néerl. Zool. 10: 241 - 264 Coox, Emity E 1962. _A study of food choice of two opisthobranchs, Rostanga pulchra McFartanp and Archidoris montereyensis (Coo- PER). The Veliger 4 (4): 194-196; 4 text figs. (1 April 1962) Exiot, Cuartes N. E. 1908. Reports on the marine biology of the Sudanese Red Sea. XI. Notes on the collection of nudibranchs from the Red Sea. Journ. Linn. Soc. 31: 86 - 122 Forrest, J. E. 1953. | On the feeding habits and the morphology and mode of functioning of the alimentary canal in some littoral dorid nudi- branchiate mollusca. Proc. Linn. Soc. London 164: 225 - 235 GuisELiIn, MicHarL TENANT 1964. Feeding of Dendrodoris (Doriopsilla) albopunctata, an opisthobranch gastropod. Ann. Reprt. Amer. Malacol. Union 1964: 45 - 46 Gonar, H. A. FE « G. N. SoLtiman 1967. The biology and development of Dendrodoris (Dorid- opsis) fumata (Rupp and Leuck) (Gastropoda: Nudibranchia). Publ. Mar. biol. Sta. Al Ghardaqa (Red Sea) 14: 31 - 54 GraHAM, ALASTAIR 1955. Molluscan diets. 144 -159. McBetu, JAMES WARREN 1968. Feeding behavior of Corambella steinbergae. The Veliger 11 (2): 145 - 146 (1 October 1968) 1970. The deposition and biochemistry of carotenoid pigments in nudibranchiate molluscs. Ph. D. dissertation, Univ. Calif., San Diego McMiutan, N. 1942. Food of nudibranchs. Miter, Micuaet CuHares 1961. Distribution and food of the nudibranchiate Mollusca of the South of the Isle of Man. Journ. Anim. Ecol. 30: Proc. Malac. Soc. London 31: Journ. Conchol. 21 (10) : 327 95 - 116 1965. | Grazing carnivores — some sea slugs feeding on sedentary invertebrates. Poirieria 3: 1 - 11 Morse, Patricia M. 1967. On the structure and function of the digestive system of the nudibranch mollusc, Acanthodoris pilosa. Ph. D. dissert. Univ. New Hampshire Pruvot-Fo., ALICE 1954. Mollusques opisthobranches. In Faune de France, 58: 460 pp.; 1 plt.; 173 text figs.; Paris, Paul Lechevalier. RussEL_, Henry D. 1964. | New England nudibranch notes. 37 - 42 STEHOUWER, E. C. 1952. The preference of the slug Aeolidia papillosa (L.) for the sea anemone Metridium senile (L.). Arch. Neéerl. Zool. 10: 161 - 170. SWENNEN, C. 1961. Data on distribution, reproduction, and ecology of the nudibranchiate Mollusca occurring in the Netherlands. Netherl. Journ. Sea Res. 1 (1-2): 191-240 The Nautilus 78: Vol. 14; No. 2 THE VELIGER Page 161 Tuompson, THomas EvERETT 1958. The natural history, embryology, larval biology and post- larval development of Adalaria proxima (Alder and Hancock) (Gastropoda, Opisthobranchia). Phil. Trans. Roy. Soc. London B 242: 1 - 58 1962. Studies on the ontogeny of Tritonia hombergi Cuvier (Gastropoda, Opisthobranchia) . Phil. Trans. Roy. Soc. London B 245: 171 - 218 1964. | Grazing and the life cycles of British nudibranchs. Brit. Ecol. Soc. Symp. 4: Grazing in terrestrial and marine environments, ed. D. J.Crisp. Blackwell, Oxford: 275 - 297 Younc, Davin KENNETH 1966. Systematics, food and functional morphology of the feed- ing apparatus of some dorid nudibranchs. Ph. D. dissert. Univ. Hawaii, Honolulu. 1967. New records of Nudibranchia (Gastropoda : Opistho- branchia : Nudibranchia) from the Central and West-Central Pacific with a description of a new species. The Veliger 10 (2): 159-173; 18 text figs. (1 October 1967) Page 162 THE VELIGER Vol. 14; No. 2 Range Extensions of Some Northeast Pacific Nudibranchs (Mollusca : Gastropoda : Opisthobranchia ) to Washington and British Columbia, with Notes on their Biology BY GORDON A. ROBILLIARD Friday Harbor Laboratories and Department of Zoology, University of Washington, Seattle, Washington 98105 INTRODUCTION THERE HAS BEEN no extensive investigation of the opis- thobranchs from Washington and British Columbia since O’DonocHuz (see his 1927 paper for bibliography) pub- lished a series of papers dealing with systematics, mor- phology, reproduction, color variations, and geographic distribution of species found near Nanaimo, British Co- lumbia. Numerous papers and even a monograph (Mac- FarLAND, 1966) concerning the opisthobranchs of Cali- fornia and Baja California have been published. In par- ticular, many papers dealing with range extensions and geographic distribution of opisthobranchs have been pub- lished recently (BErTscH, 1969; GosLINER & WILLIAMS, 1970; Lance, 1961, 1966; Lone, 1969; Rotter, 1970; RoLier & Lone, 1969; SpHoN « Lance, 1968; STEIN- BERG, 1963; and others), but these deal with species found in California. Often, they only incidentally include the ‘total’ geographic range which may or may not in- clude Washington, British Columbia, and Alaska, and which may be incomplete. Over the past 5 years, while collecting nudibranchs from the intertidal and subtidal (with SCUBA) in the Washington and southern British Columbia area, I have found a number of species that have not previously been reported from the area. The range extension in almost all cases is at least from San Francisco Bay or Monterey Bay, California, to San Juan Island, Washington, a straight line distance of about 800 statute miles. A few other species have been reported in the literature (e. g., Horst, 1967), but the range extensions have been omit- ted by the above listed authors. The range extensions plus brief notes, where appropri- ate, on feeding, reproduction, color and morphologicai variation, depth range, and assorted miscellania are the subject of this paper. Undoubtedly, as more biologists Geographical Locations in Washington and British Columbia Longitude Location Latitude Alki Point, Seattle, Washington 122°24’36” 47°34'10” Bamfield, Barkley Sound, Brit. Columbia 125°08’45” 48°50’25” Muchalat Arm, British Columbia 126°18’ 49°40/ Mukkaw Bay, Washington 124°40’ 48°19715” Nanaimo, British Columbia 123°57’ 49°12’ Saltspring Island, British Columbia 123°33’ 48°45’ San Juan Island, Washington 123°05’ 48°30’ Umatilla Reef, Washington 124°47’ 48°11’ Victoria, British Columbia 123°23/36” 48°2448” become interested in the opisthobranchs from Washington and British Columbia, and especially in those on the open coast where relatively little collecting or research has been done, the range of some species will be extended, new species will be discovered, and interesting new or confir- matory observations on their natural history will be made. It is hoped that this paper and others in this projected series will help to stimulate this interest. NEW RANGE EXTENSIONS Ancula pacifica MacFarland, 1905 Lance (1961) reports this species from as far south as Point Loma, California, and BEHRENS (1971) found it to be relatively common in San Francisco Bay in the summer. On June 10, 1967 and May 21, 1969, I found 2 animals, 10 and 7 mm long respectively, in the intertidal on San Juan Island, Washington. Neither specimen exhibited the orange or yellow line on the indistinct pallial ridge, between the extrabranchial Vol. 14; No. 2 papillae, on the caudal crest, or on the midline of the dorsum which MacFartanp (1966) describes. The yel- low pigment is present in the rhinophores, the accessory rhinophore papillae, the branchiae, and the extrabranchi- al papillae. The animals match MacFartanp’s (1966) description in all other respects. Cadlina modesta MacFarland, 1966 Bertscu (1960) reports that the species occurs from La Jolla, California to Moss Beach [San Mateo County], California. I have collected at least 30 animals from Na- naimo, Bamfield, and in Muchalat Arm, all on Vancouver Island, and from San Juan Island, Washington. Most were seen between December and August. All the animals have been on a rocky substratum from the intertidal to over 50 m, usually near sponges which they probably eat. Most of the nudibranchs were 15-25 mm long, although a few were up to 45 mm long. No egg masses or copulating pairs were seen in the field. Catriona alpha (Baba & Hamatani, 1963) Lance (1966) reports the species from Mission Bay, Newport Bay, and Santa Barbara in California, and from Japan. I collected many animals in late May, 1969 and 1970 on San Juan Island and a few in early July, 1970 at Victoria. They were on floats or on gravel substratum to depths of 25m. The principal prey, both on the floats and in the sublittoral, is the hydroid, Tubularia marina Torrey, 1902 and Tubularia sp. Only a few were apparently feeding on other hydroids such as Obelia sp. and Syn- coryne eximia (Allman, 1859) on the floats. Catriona is very difficult to see when it is on the hydranth of Tubu- laria or among Syncoryne polyps due to the red color of the digestive diverticula in the cerata. Numerous eggs were present in May, 1970, usually on the stalks of Obelia and Tubularia. The size range of Catriona was 5-13 mm long, but those less than about 6 - 7 mm long apparently were not sexually mature as they were not observed to copulate or spawn. Dirona aurantia Hurst, 1966 Hurst (1966) collected Dirona aurantia from Orcas Island, Blakely Island, and San Juan Island from floats and to depths of 30 fathoms. Although the range exten- sions are not very significant (less than 80 miles), I have collected D. aurantia as far south as Alki Point, Seattle, north to Saltspring Island, and west to Victoria. It is relatively common on floats and piles, and on gravel-shell bottoms to at least 60 m. A few small specimens (less than 30mm long) may be present from May through August, but the majority of THE VELIGER Page 163 the population is seen between September and April. Some specimens grow as large as 120 mm long, but most mature ones are 50 - 80 mm long. In the field, eggs are seen from January to April and occasionally May. Hurst (op. cit.) lists hydroids, bryozoans, amphipods, and plant material as components of the diet of Dirona aurantia. As a result of extensive field observations and examina- tion of fecal pellets of freshly collected animals, I conclude that the major component (about 75%) of the diet is one or more species of arborescent bryozoans (Bugula sp. or Flustrella sp., or both) which are abundant wherever D. aurantia has been collected. Amphipods, hydroids, tuni- cates, polychaetes, etc., are part of the epifauna that lives on these bryozoans and are ingested more or less fortu- itously. Eubranchus (= Capellinia) rustyus (Marcus, 1961) San Francisco Bay, California and Bahia de los Angeles in the Gulf of California mark the presently known north- ern and southern limits, respectively, of the range of Eubranchus rustyus (LANcE, 1961; RoLLeR & Lone, 1969). This species is very common in the San Juan Archipelago, Washington, and was found in abundance at Bamfield, British Columbia in June 1970. In the San Juan Archipelago, Eubranchus rustyus is a spring-summer species, being most abundant from April through September. A few were present in March and October, but none were seen from November through February. The animals, found on floats and to depths of 20 m, are almost always on or near the hydroid Plumula- ria lagenifera Allman, 1885. Like E. oliwaceus (O’Dono- GHUE, 1922), E. rustyus is gregarious, there often being 10 - 50 animals on a single hydroid colony. As Plumularia may be abundant in large patches (up to 200 m’ at least), it is not uncommon to find thousands of E. rustyus at one time. Eggs are deposited from April through early October on the Plumularia. The length of larval life is not known, but after metamorphosis, Eubranchus rustyus takes about 3 - 5 weeks to become sexually mature (6-10 mm long). Animals up to 25 mm long have been collected but most were 8 - 15 mm long. The color pattern of Eubranchus rustyus in the San Juan Islands is slightly different from that described and shown by MacFarianp (1966: p. 323; plt. 62) for E. occidentalis (a junior synonym of E. rustyus; see ROLLER, 1970). There are few flecks of green on the body; rather, there are numerous rusty-brown patches scattered over the sides, dorsum, and cerata. In some animals, these patches are dense enough to form a conspicuous brown line between the cerata on the dorso-lateral margin of the body (see also MacFartanp, 1966). There are a few Page 164 white patches sparsely scattered on the dorsum of some specimens, but very few of the tiny yellow spots men- tioned by MacFarLanp (op. cit.) were seen. The tips of the cerata and rhinophores may be sparsely to densely covered with flecks of opaque white pigment. About half way up, there is an indistinct band of white flecks encirc- ling the cerata and just distal to this, there is an indistinct band of rusty-brown flecks. There is also a band of rusty- brown pigment on the distal half of the rhinophores and oral tentacles of most animals. Precuthona divae Marcus, 1961 This species has been found from Dillon Beach, Cali- nia (STEINBERG, 1963) to Santa Barbara County, Calli- fornia (SPHON & Lance, 1968). Five animals, ranging in length from 10 to 30 mm, were collected from San Juan Island, Washington, between August and October, 1969. Two were at a depth of 20m on a rock wall covered with hydroids: Garveia annulata Nutting, 1901; Tubularia sp.; Abietinaria spp.; and others. The other 3 were at 10 m on a mud bottom where the only prey species was Tubularia sp. At both places, I found egg masses in August. The white ribbon, deposited in a tight spiral, is similar to that of Acanthodoris hudsoni MacFarland, 1905 (see Hurst, 1967, fig. 2), except that the free edge is even more fluted. Two of these egg masses were infested with the egg- sucking sacoglossan, Olea hansineensis Agersborg, 1923. Trinchesia (= Cratena) abronia (MacFarland, 1966) So far, Trinchesia abronia has only been reported from Monterey to Pismo Beach, California (ROLLER & Lona, 1969). One specimen, 10 mm long, was collected at Muk- kaw Bay on the Olympic Peninsula of Washington by Pamela Roe and brought to me for identification. It fits exactly the description given by MAcFartanp (1966) for this species. No other specimens have been collected to date. RANGE EXTENSIONS IN Hurst (1967) Hurst (1967) listed range extensions for 6 species [Aust- rodoris odhneri MacFarland, 1966; Catriona aurantia (Alder « Hancock, 1842); Chelidonura phocae Marcus, 1961; Cratena albocrusta MacFarland, 1966; Cumanotus beaumonti (Eliot, 1908); Onchidoris muricata (Miller, 1776) | to the San Juan Islands from various areas in California and from the Atlantic. Chelidonura phocae, as listed by Hurst, is almost surely Aglaja ocelligera (Bergh, 1894) (Larry Andrews, personal communication), which is very common in sheltered bays in Washington and THE VELIGER Vol. 14; No. 2 southern British Columbia (author’s unpublished obser- vations). Archidoris (= Austrodoris) odhnert RoLier & Lone (1969) limit the northern range of this species to Monterey, apparently having overlooked the range extension in Hurst (1967). Besides being very abundant in the San Juan Islands (author’s unpublished observations), Archidoris odhneri is found at Nanaimo and Bamfield in British Columbia, and at Umatilla Reef on Washington’s west coast. It occurs on floats and on rock or gravel substrata to at least 60 m, and is present throughout the year. Although most mature animals are from 50 to 100 mm long, a few individuals up to 130mm long have been seen. Copulating pairs and egg masses are present through- out the year, although never in abundance. Archidoris odhneri is a relatively unspecialized sponge predator, preying on: Halichondria panicea (Pallas, 1766) ; Styl- issa stipitata de Laubenfels, 1961; Tedania sp.; Syringella amphispicula de Laubenfels, 1961; Craniella sp.;a hexact- inellid sponge, possibly Rhabdocalyptus sp.; and at least 2 other unidentified species. Although Archidoris odhneri is usually white, occasion- ally a specimen that is cadmium yellow (Grumbacher oil color chart) is found. That these yellow ones are A. odhnerz is substantiated by the fact that they copulate with the white ones and produce viable veligers. Trinchesia (= Cratena) albocrusta Rotter « Lone (1969) list the range as being from Monterey to Santa Barbara, California. However, Hurst (1967) extended the range to the San Juan Islands, al- though she used MacFarland’s genus name. I have not collected this species from Washington or British Colum- bia to date. One other species, Acanthodoris brunnea MacFarland, 1905, deserves mention. According to RoLLER & Lone (1969), A. brunnea is restricted to the Monterey-Santa Barbara region in California. There are a number of ref- erences to its occurrence in the San Juan Islands and at Nanaimo, British Columbia (MaAcFar.anp, 1966; O’Do- NOGHUE, 1926; Hurst, 1967). I have found a number of specimens up to 25mm long in the winter months from the intertidal to 30 m in the San Juan Islands and at Victoria, British Columbia. SUMMARY The geographic range of 6 species [Ancula pacifica Mac- Farland, 1905; Cadlina modesta MacFarland, 1966; Cat- Vol. 14; No. 2 THE VELIGER riona alpha (Baba & Hamatani, 1963) ; Ewbranchus rus- tyus (Marcus, 1961); Precuthona divae Marcus, 1961; Trinchesia abronia (MacFarland, 1966)] is extended from central-southern California to San Juan Island, Washing- ton. The range of Dirona aurantia Hurst, 1966 is extended from the San Juan Archipelago to most of Puget Sound and the southern British Columbia area. The occurrence of Archidoris odhnert (MacFarland, 1966), Trinchesia albocrusta (MacFarland, 1966), and Acanthodoris brun- nea MacFarland, 1905 in the San Juan Islands or south- ern British Columbia, or both, is reiterated. Where known, observations on prey, reproduction, depth range, and color and morphological variation of these species are presented. ACKNOWLEDGMENTS I am grateful to Larry Andrews and Richard Roller for advice and confirmation of identifications of various spe- cies; to numerous people at Friday Harbor Laboratories and University of Washington, Department of Zoology for both opisthobranchs and information concerning their natural history; and to Dr. Robert Fernald, Director, Friday Harbor Laboratories, for the use of the facilities at the Laboratories, where most of the work has been done. The support of the Ecology Training Grant to the Department of Zoology, University of Washington (NSF no. GB6518X and GB20978) and a National Research Council of Canada Postgraduate Scholarship is gratefully acknowledged. Literature Cited BEHRENS, Davip W. 1971. The occurrence of Ancula pacifica MacFarland in San Francisco Bay. The Veliger 13 (3): 297 - 298 (1 January 1971) Bertscu, Hans 1969. Cadlina modesta: a range extension, with notes on habitat and a color variation. The Veliger 12 (2): 231 - 232; 1 text fig. (1 October 1969) GosLiNER, TERRENCE M. « Gary C. WILLIAMS 1970. The opisthobranch mollusks from Marin County (Cali- Page 165 fornia (Gastropoda). The Veliger 13 (2): 175-180; 1 map (1 October 1970) Hurst, ANNE 1966. A description of a new species of Dirona from the North-East Pacific. The Veliger 9 (1): 9-15; plt. 2; 7 text figs. (1 July 1966) 1967. The egg masses and veligers of thirty Northeast Pacific opisthobranchs. The Veliger 9 (3): 255 - 288; plts. 26 - 38; 31 text figs. (1 January 1967) Lance, JAMES RoBERT 1961. A distributional list of southern California opistho- branchs. The Veliger 4 (2) : 64-69 (1 October 1961) 1966. | New distributional records of some northeastern Pacific Opisthobranchiata (Mollusca:Gastropoda) with descriptions of two new species. The Veliger 9(1): 69-81; figs. 1-12 (1 July 1966) Lone, STEVEN J. 1969. Two new records of Cratena abronia MacFarLanp, 1966 (Nudibranchia : Eolidacea). The Veliger 11 (3): 281 (1 January 1969) MacFarianb, FRANK Mace 1966. Studies of opisthobranchiate mollusks of the Pacific Coast of North America. Mem. Calif. Acad. Sci. 6: xvi + 546 pp.; 72 plts. (8 April 1966) O’DonocuHue, CHarRLes HENRY 1926. A list of nudibranchiate mollusca recorded from the Pacific Coast of North America, with notes on their distribu- tion. Trans. Roy. Canad. Inst. 15 (2): 199 - 247 1927. Notes on a collection of nudibranchs from Laguna Beach, California. | Journ. Entomol. Zool. Pomona Coll. 19: 77 - 119 Ro ier, Ricuarp A. 1970a. A list of recommended nomenclatural changes for Mac- Farland’s “Studies on opisthobranchiate mollusks of the Pa- cific Coast of North America.” The Veliger 12 (3) : 371 to 374 (1 January 1970) 1970b. A supplement to the annotated list of opisthobranchs from San Luis Obispo County, California. The Veliger 12 (4): 482 - 483 (1 April 1970) Rotter, Ricuarp A. « STEVEN J. Lonc 1969. An annotated list of opisthobranchs from San Luis Obis- po County, California. The Veliger 11 (4): 424-430; 1 map (1 April 1969) SpHon, Gate G., Jr. & James Ropert LANCE 1968. An annotated list of nudibranchs and their allies from Santa Barbara County, California. Proc. Calif. Acad. Sci. 36 (3): 73-84; 1 fig. (25 September 1968) STEINBERG, JOAN EMILY 1963. Notes on the opisthobranchs of the west coast of North America. — IV. A distributional list of opisthobranchs from Point Conception to Vancouver Island. The Veliger 6 (2): 68 - 73 (1 October 1963) Page 166 THE VELIGER Vol. 14; No. 2 Veliger Development in Dendronotus frondosus (Ascanius, 1774) (Gastropoda : Nudibranchia) BY LESLIE G. WILLIAMS Pacific Marine Station, University of the Pacific, Dillon Beach, Marin County, California 94929 (5 Text figures) INTRODUCTION EMBRYOLOGY AND VELIGER development has been con- sidered in 6 species of the sub-order Dendronotoidea (Order Nudibranchia). THompson (1962) described the ontogeny and metamorphosis of a British tritoniid, Tritonia hombergi (Cuvier, 1797). Rem (1846) gave only a cursory account of the early embryology in the dendro- notids, Dendronotus arborescens (= frondosus) and Doto coronata (Gmelin, 1791). Hurst (1967) described the veliger shell and characterized the veliger morphology of a tritoniid, Tritonia exsulans Bergh, 1894; a fimbriid, Melibe leonina (Gould, 1853); and 2 dendronotids, Dend- ronotus iris Cooper, 1863, and D. frondosus (Ascanius, 1774). The present paper includes a description of the veliger morphology and development of Dendronotus frondosus. In addition, a detailed larval shell description of the pelagic veliger is provided. The results are discussed with respect to veliger development and morphology in the Dendronotoidea. METHODS ann MATERIALS Seven individuals of Dendronotus frondosus were collected from hydroid epiphytes occurring on Zostera marina Lin- naeus, 1753. The Z. marina had previously been dredged from Lawson’s channel in Tomales Bay, California, on 9 July 1970, and placed on a seawater table. Identification of Dendronotus frondosus specimens was based on a recent review of the family Dendronotiidae by Ropi_iiarp (1970). The 7 Dendronotus frondosus and several blades of Zos- tera marina bearing epiphytic hydroids were isolated in a plastic aquarium and supplied with running seawater. Eight egg masses were deposited on the hydroid epi- phytes over a 4-day period from 27 July to 30 July 1970. Each egg mass was isolated in a stender dish (62 36 mm) containing filtered seawater and placed in a refrig- erator at 14.0° C. The water was changed every other day while the veligers were still in the egg mass. After hatch- ing, the water was changed on a daily basis. Free swim- ming veligers were fed daily with 2 drops of cultured Monochrysis luthert Droop, 1953. Observations of living material were made with a com- pound microscope, using either controlled bright field illumination or phase contrast illumination. Additional observations were made from photographs taken with a 35mm camera mounted on a compound microscope. Veligers were relaxed in a dilute magnesium chloride so- lution to facilitate observations and photography. During metamorphosis, discarded veliger shells were placed in a 5% ethanol and seawater solution and set aside for later examination. RESULTS Early Embryology The early embryology of Dendronotus frondosus is given only a cursory appraisal in this study. The results pertaining to oogenesis and cleavage recapitulate Living- stone’s (unpublished) observations. A more complete ac- count of the early embryology is being considered by Livingstone. The approximate developmental rate from egg mass deposition to shell-loss for D. frondosus is shown in Table 1. Completion of oogenesis occurs within the egg capsule shortly after egg mass deposition. The first polar body separates from the ovum approximately one hour after egg mass deposition, with the second polar body appearing about 30 minutes later. Cleavage follows the spiral pattern, typical of the Mol- lusca. ‘The first 3 cleavage divisions are synchronous. The first and second cleavages are holoblastic and equal. The Vol. 14; No. 2 Table 1 Developmental Rate for Dendronotus frondosus cultured in seawater at approximately 14.0° C $ F 3 Developmental Sta; 3 g gf é 2 e 5 3 : se Ode First polar body 1.00 1.00 Second polar body 0.25 1.25 First cleavage 1.75 3.00 Second cleavage 1.00 4.00 Third cleavage 2.50 6.50 Fourth cleavage 2.00 8.50 blastula 16.50 25.00 gastrula 4.75 30.25 trochophore 18.00 48.25 early veliger 13.50 61.75 alimentary differentiation 13.00 74.75 hatching 72.25 147.00 shell-loss 26.00 173.00 third cleavage is holoblastic and unequal, with the cleav- age plane oblique to the polar axis. The fourth cleavage is not synchronous. The micromeres divide more rapidly than the vegetal pole macromeres. This results in a tran- sitory 12-cell stage prior to the more typical fourth cleav- age 16-cell stage. Formation of a coeloblastula marks the end of cleavage. Gastrulation occurs by invagination and epiboly. A coelogastrula is formed by invagination of the blastopore and consequent formation of an archenteron. As epiboly ensues, the blastopore becomes sealed off by convergence. At this point, the gastrula assumes a squat, heart-shaped configuration. Formation of the trochophore is marked by the forma- tion of the prototroch anterior to the site of the closed blastopore. During the trochophore stage, the shell gland and anal cells develop. With continued development of the trochophore, shell formation is initiated, the velar lobes separate, stomodaeal invagination occurs and inter- nal differentiation takes place. The larva is now the early veliger. The Early Veliger The early veliger is identified with the separation of velar lobes at 61.75 hours after deposition of the egg mass and ends with the completion of internal alimentary differentiation after 74.75 hours. The shape is “squat” with large refractile granules located along the upper margin of the shell. THE VELIGER Page 167 The early veliger is depicted in Figure 1. For descrip- tive purposes, all veligers are illustrated such that an imaginary line running through the stomodaeum to the medial margin of the retractor muscle-shell articulation represents the ventro-dorsal axis. The antero-posterior axis is delimited by an imaginary line that runs between the dorsal extremities of the paired velar lobes; is per- pendicular to the ventro-dorsal axis; and runs between the paired statocysts. 5 Figure 1 Early Veliger a: left lateral view b: ventral view an — anus ft — foot int — intestine Ik — larval kidney m—mantle mf—mantle fold prm — pedal retractor muscle sh — shell st — stomach stom — stomodaeum svr — subvelar ridge vrm — velar retractor muscle es — esophagus Idd —left digestive diverticulum lrm — left retractor muscle mm -— mantle muscle Pvs — perivisceral space sta — statocyst vel — velum Shell Development: The early “squat” veliger has a cap-like shell. Approx- imate dimensions of this shell are: length, 146; width, 120; and depth, 50 - 60u. Page 168 The shell becomes successively cup-like and then dome- like, as shown in Figure 2. Thus, the veliger shell appears to be the inflated variety referred to as type C by THor- son (1946) and characterized as type 2 by THomPsSoN (1961) and Hurst (1967). Average dimensions of the mature veliger are: length, 1864; width, 141; and depth, 210u. Cc 108 pw _——— | Figure 2 Shell Development a: early veliger cap shaped shell b: pre-hatching veliger cup shaped shell c: free swimming veliger dome shaped shell The position of the larval kidney and the anus to the right side of the cephalopedal mass indicate that the Dendronotus frondosus veliger is dextrally asymmetrical. The larval shell appears to be slightly sinistral. However, on the basis of the morphological organization, the larval shell is believed to be hyperstrophic, a modification of dextral coiling (THompson, 1958; Horrkosut, 1967). Mantle and Mantle Derivatives In the early veliger, the mantle is contiguous with the shell and, at the margin of the shell aperture, is folded medially to connect with the dorsal margin of the velar lobes and foot. The mantle fold appears to extend beyond the margin of the shell aperture. During this time, large refractile granules are present in the tissue of the mantle fold. As the shell elongates, the mantle fold is apparent as a thickened region of darkly pigmented cells, which lie THE VELIGER Vol. 14; No. 2 between the anterolateral margin of the shell aperture and the velar lobes. Figure 3 Left lateral view of a cup shaped veliger showing slight dissociation of the perivisceral membrane from the shell Ik - larval kidney mc-—mantle cavity mf—mantle fold mm — mantle muscle op — operculum prm — pedal retractor muscle pvm — perivisceral membrane Pvs — perivisceral space sc — shell cavity sh — shell vrm — velar retractor muscle The mantle cavity is a shallow space anterior to the connection of the mantle fold with the dorsal margin of the velar lobes. The unfolded portion of the mantle remains contiguous with the inner surface of the shell, but becomes increas- ingly thin and transparent as the shell assumes a cup- shape. This portion of the mantle may now be designated the perivisceral membrane (Figure 3). As the shell be- comes dome-like, the perivisceral membrane pulls away from the inner shell surface, forming an intermediate shell cavity in the process (Figure 4). At the same time, 4 to 6 darkly pigmented, constricted pits appear on the free surface of the perivisceral membrane. These pits suggest contractile elements within the perivisceral mem- brane. Velum The bilobed velum is small, vacuolated, and bears stout cilia. Mean ciliary length is 44.0u. The velum extends anteriorly to the mantle fold and laterally to the shell margin. No morphological changes in velar structure are observed during development beyond the early veliger. Vol. 14; No. 2 THE VELIGER Page 169 The velum is consistently oriented with the anterior end held proximal to the shell aperture and the posterior end held distal to the shell aperture (Figures 1, 3, and 4). A small, finely ciliated sub-velar ridge is present in the early veliger, and in later veliger stages. Figure 4 Free swimming veliger showing nearly complete dissociation of the perivisceral membrane from the shell cp —contractile pit mm -—mantle muscle pvm — perivisceral membrane Pvs — perivisceral space sc — shell cavity Foot and Operculum: The foot originates immediately posterior to the stomo- daeum and extends back about 45.0u. The foot is evenly ciliated and bears long sensory cilia at its posterior apex. Cilia on the foot proper have a mean length of 9.3. The sensory cilia, however, have a mean length of 17.0u. The operculum forms on the postero-dorsal portion of the foot during development from a cup-shaped to a dome-shaped veliger. The operculum becomes fully de- veloped just prior to hatching. Mean length of the oper- culum at hatching is 30.3. Visceral Mass: As the alimentary tract, digestive diverticula, larval kidney and larval musculature are differentiated, a fluid- filled internal perivisceral space is developed (Figures 1, 3, and 4). The perivisceral space is enclosed by the peri- visceral membrane. In the early veliger, the esophagus extends antero- dorsally from the stomodaeum, bends above the velar lobes and extends postero-dorsally to join the stomach. The stomach extends dorsally into the right side of the perivisceral cavity and lies adjacent to the inner dorsal surface of the perivisceral membrane (Figure la). The intestine originates on the right antero-dorsal surface of the stomach, and passes postero-ventrally to exit through the anus on the right ventral surface of the foot (Figure 1b). As the veliger elongates, the larval alimentary system occupies less space within the perivisceral cavity (Figures 3 and 4). The esophagus tends to straighten out, conse- quently reducing its curvature above the velum. The stomach, however, bends antero-dorsally into the right side of the perivisceral space. The larval kidney is located in the right ventral portion of the perivisceral space immediately anterior to the in- testine (Figure 1b). The larval kidney undergoes only a slight amount of growth subsequent to early veliger for- mation. The kidney pore was observed only in free-swim- ming veligers. Two digestive diverticula are differentiated in the early veliger. The larger, left diverticulum, lies adjacent to the left posteroventral portion of the stomach immediately above the esophageal-stomach confluence. 'The smaller, right diverticulum lies adjacent to the right anteroventral esophageal-stomach confluence. The digestive diverticula develop lumina as the veliger assumes its cup-like shape. The lumina of the digestive diverticula communicate with the alimentary canal in the dome-shaped veliger. Musculature: The paired right and left retractor muscles articulate on the inner left dorsal surface of the veliger shell. The retractors extend ventrally and to the left side of the stomach. At this point each retractor gives off 3 main branches: a velar retractor muscle, a pedal retractor muscle, and a visceral retractor muscle (Figures la, 3, and 4). The left pedal muscle circumscribes the left side of the esophagus and inserts within the foot, while the right pedal muscle circumscribes the right side of the esophagus and inserts within the foot. The velar retractor muscles insert on the anterior and anterolateral portions of the velar lobes. The right visceral retractor sends sev- eral branches to the stomach while the left visceral retrac- tor sends several branches to the esophagus. The retractor muscles remain constant in their insertion and orientation throughout the pre-metamorphosis veliger development. There are 2 pairs of mantle muscles in the early veliger. One pair originates on the anterior wall of the perivisceral membrane and inserts on the anterior mantle fold. The second pair originates above the first pair on the perivis- ceral membrane and inserts on the paired velar retractor muscles (Figure la). Page 170 Three additional mantle muscles develop as the elon- gate veliger form is assumed. A pair of muscles develops on the anterior perivisceral membrane and inserts on the esophagus. A single muscle articulates with the perivis- ceral membrane adjacent to the paired retractor-shell articulation and extends postero-ventrally to insert on the dorsal surface of the stomach (Figures 3 and 4). Free Swimming Veliger: The mean time of hatching for developing veligers is 147 hours after egg deposition. The free swimming veligers exhibit several behavioral and morphological changes prior to metamorphosis. Some veligers swim about and become stuck on the water sur- face of the culture vessels. Most of the veligers, however, settle and begin to contract the velar retractor muscles or sporadically swim about close to the bottom. Rapid chan- ges of light intensity cause free swimming veligers to con- tract the velar retractor muscles and partially withdraw the velum into the shell. Small particles rotating in the stomach and in the left digestive diverticula indicate that the veligers were feeding on Monochrysis. In the settled veligers the mantle fold separates from the shell perimeter and allows a complete withdrawal of the velum into the shell. The outer perivisceral membrane dissociates from the inner shell surface with the exception of the retractor-shell articulation and the operculum-shell articulation. Finally, the perivisceral membrane collapses, the retractor articulation is lost, the operculum is lost, and the veliger discards its shell. Mean time for the shell loss was 173 hours after egg mass deposition and 26 hours after hatching. 120 bh — Figure 5 Free swimming shell-less veliger pvm — perivisceral membrane stom — stomodaeum ft — foot sta — statocyst vel — velum THE VELIGER Vol. 14; No. 2 Many shell-less veligers were observed to swim about with a long ligament-like thread trailing behind the foot (Figure 5). Velum, statocysts, foot, and stomodaeum are easily seen in free swimming, shell-less veligers. Internal details, however, are not easily seen through the collapsed perivisceral membrane. Further metamorphosis was not observed to occur, presumably due to the lack of suitable substrate (THompson, 1958, 1962). DISCUSSION Hurst (1967) does not adequately represent veliger de- velopment and morphology in Dendronotus frondosus. She presented a generalized description of veliger morphology based on THompson’s (1961) type 2 larval shell, but made no specific reference to morphological detail in D. frondosus. There is also an apparent disparity in Hurst’s veliger shell description for D. frondosus (Hurst, op. cit., pp. 276 - 277): “The size, shape and sculptural patterns do not vary much intra-specifically. and are characteristic of their species ... No marked sculptural patterns were present in the [type 2] shells of species included here although those of Dendronotus frondosus (pos- sibly D. rufus) were observed to have definite char- acteristic lines on the veliger shell.” The present study concurs with Hurst’s (1967) type 2 classification of the Dendronotus frondosus veliger shell. Striations, however, were not evident during veliger de- velopment, nor in shells discarded during metamorphosis. TuHompson (1961) has recognized 2 types of larval shells: Type 1, spiral shells normally forming 3 to 1 whorl only; Type 2, egg shaped or inflated shells. Drawing upon TuIELE’s (1931) systematics, Thompson ably demon- strates that families in the stirps Doridacea (= Holohepa- tica) are consistently represented by Type 1 larval shells, while families in the stirps Aeolidacea (— Cladohepatica) are represented either by Type 1 or Type 2 larval shells. THOMPSON (op. cit., p. 237) concludes that “it is time the obviously polyphyletic origin of the eolidiform nudi- branchs was more accurately reflected in opisthobranch classification.” A more recent review of opisthobranch systematics by Taytor & Sout (1962) reveals a more uniform associa- tion among those families represented by Type 2 larval shells. Thus, with one exception, families with Type 2 larval shells are found in the eolidoidean infra-order Acleioprocta. The Type 2 larval shells of Dendronotus frondosus and D. iris (Hurst, 1967) prove to be the exception. If larval shell type is afforded the rank of a taxonomically diagnostic characteristic, the monogeneric Vol. 14; No. 2 THE VELIGER Pacem family Dendronotiidae apparently represents a systematic anomaly within the suborder Dendronotoidea. One must consider, however, that Taytor & Sout (1962) list 10 families in the Dendronotoidea. In only 5 of these families has larval shell type been recorded (THompson, 1961; Hurst, 1967). Any conclusions with respect to larval shell type as an indicator of polyphyletic origins in the Nudibranchia should, therefore, await further appraisals of larval development in the dendronotoidean and eolido- idean families not yet studied. The major morphological changes during veliger devel- opment in Dendronotus frondosus are inflation of the shell, differentiation of the mantle fold and perivisceral mem- brane, appearance of the shallow mantle cavity, forma- tion of the mantle muscles, and formation of the opercu- lum. THompson’s (1962) description of the ontogeny in Tritonia hombergi Cuvier, 1797, offers a specific example within the Dendronotoidea for comparison of larval mor- phology in Dendronotus frondosus. The most immediate difference between the 2 larvae is manifest in their oppos- ing shell types. The Type 1 larval shell of T: hombergi rep- resents not only a structural difference with respect to the Dendronotus larval shell, but is also relevant to morpho- logical differences between the 2. Appearance of a shallow mantle cavity, and differentiation of the mantle fold and perivisceral membrane, are concomitant events following shell formation in the early D. frondosus veliger. Triton:a hombergi agrees with D. frondosus in the occurrence of these events but demonstrates a capacious mantle cavity. The difference implied by the terms “shallow” and “‘capa- cious,” however, may only be relative to the differences between the Type 2 and Type 1 larval shells respectively. The orientation and insertion of the retractor muscle com- plex of D. frondosus corresponds morphologically with T: hombergi, but the shell-retractor articulations are dissim- ilar, presumably due to the difference in shell type. Mantle muscles were not described in T: hombergi, consequently no comparison is made with the mantle musculature ob- served in D. frondosus. The dissociation of the mantle fold from the shell aperture, withdrawal of the velum and foot into the shell, and the subsequent loss of shell and operculum, occur similarly in Dendronotus frondosus and Tritonia homberg?. In Tritonia, however, settling occurred on the alcyonacean Alcyonium digitatum and resulted in complete metamor- phosis to the young adult. A hydroid substrate was not provided for the D. frondosus cultures. Lack of suitable settling substrate offers a possible explanation for the con- tinued swimming of some of the shell-less veligers and the failure for further metamorphosis to occur. ACKNOWLEDGMENTS I would like to thank Dr. James A. Blake for his informa- tive suggestions with respect to larval culture and _ bio- logical illustration techniques. Secondly, I am indebted to Dr. Blake for his critical review of the manuscript. My appreciation also goes to Mr. David H. Montgomery for his enthusiastic and knowledgeable suggestions pertaining to the biology of the Nudibranchia. Literature Cited Hortxosut, MAsuoxr 1967. | Reproduction, larval features and life history of Phil- ine denticulata (J. Apams) (Mollusca-Tectibranchia) Ophelia 4 (1): 43 - 84 Hurst, ANNE 1967. The ege masses and veligers of thirty Northeast Pacific opisthobranchs. The Veliger 9 (3) : 255 - 288; plts. 26 - 38; 31 text figs. (1 January 1967) Rep, JOHN 1846. On the development of the ova of the nudibranchiate Mollusca. Ann. Mag. Nat. Hist. 17: 377 - 389 RosiLiiarRD, Gorpon A. 1970. ‘The systematics and some aspects of the ecology of the genus Dendronotus. The Veliger 12 (4): 433-479; plts. 63, 64; 24 text figs. (1 April 1970) TayLor, Dwicur WiLttarp & NorMAN FE SoH. 1962. An outline of gastropod classification. 1: 7 - 32 THIELE, JOHANNES 1931-1935. Handbuch der systematischen Weichtierkunde. Jena, pp. 1- 1154; 893 text figs. Tuompson, THomas EveRETT Malacologia 1958. The natural history, embryology, larval biology and post- larval development of Adalaria proxima (Alder and Hancock), (Gastropoda, Opisthobranchia). Phil. Trans. Roy. Soc. London B 242: 1 - 58 1961. The importance of the larval shell in the classification the Sacoglossa and Acoela (Gastropoda: Opisthobranchia) . Proc. Malacol. Soc. London 34 (5): 233 - 238 1962. Studies on the ontogeny of Tritonia hombergi Cuvier (Gastropoda: Opisthobranchia) . Phil. Trans. Roy. Soc. London B 245: 171 - 218 THorson, GUNNAR 1946. | Reproduction and larval development of Danish marine bottom invertebrates. | Medd. fra Komm. Dan. Fisk. Havund., Serie: Plankton; 4: 1 - 523 Page 172 THE VELIGER Vol. 14; No. 2 On the Reproductive Biology of Mitra idae (Gastropoda : Mitridae) JAMES R. CHESS ' RICHARD J. ROSENTHAL?’ Westinghouse Ocean Research Laboratory, San Diego, California 92121 (3 Plates; 4 Text figures) INTRODUCTION Motiuscan species of the genus Mitra are primarily tropical in distribution, although one member, Mitra idae Melvill , 1893, occurs off the coast of California from Crescent City south to Cedros Island, central Baja Cali- fornia (McLean, 1969). Mitra idae is typically sublitto- ral, although occasionally individuals are found at low tide. Frequently we have observed M. idae at depths of 13m to 20m on rocky substrata under the canopy of giant kelp, Macrocystis pyrifera (Linnaeus), as well as on nearshore reefs where algal cover is limited. Because of its cryptic habits, we found M. idae to be somewhat inconspicuous except during the reproductive season (Feb- ruary to July). The biology of Mitra idae has not been extensively studied, although Cate (1968) described various aspects of its mating behavior from aquarium observations. We feel that unnatural habitats often preclude or alter the normal behavior of most subtidal organisms and that data should be substantiated with field observations. This paper is concerned with the reproductive biology of Mitra idae. Included are observations on mating, pair ' Present address: National Marine Fisheries Service, Fishery Oce- anographic Center, P. O. Box 271, La Jolla, California 92037 2 Present address: Scripps Institution of Oceanography, La Jolla. California 92037 selection, spawning behavior, fecundity, and early devel- opment. Our field observations were made while SCUBA diving during the spring and summer of 1969 and 1970 in the subtidal area off Point La Jolla (Lat. 39°51’30” N; Long. 117°17’W) and Point Loma, California (Lat. 32°42’N; Long. 117°16’ W). Laboratory studies were con- ducted in La Jolla, California, at the Fishery-Oceano- graphy Center, and the Westinghouse Ocean Research Laboratory. In the laboratory the snails were maintained in fiberglass water tables which contained circulating sea water. MATING BEHAVIOR The sexes in Mitra idae are separate, but are distinguish- able in the field only during copulation. Fertilization is internal. In all of the copulating pairs we observed, the male grasped the right side or outer whorl of the female’s shell (Figure /). The copulating female was in turn firmly attached to hard substratum. In contrast, CaTE (1968) observed that on a sandy bottom in an aquarium, copulating pairs were aligned approximately parallel with neither member attached to the bottom. This be- havior might have reflected the tranquil conditions in the aquarium. Because M. idae normally occurs in areas ex- posed to heavy surge, it would appear to be advantageous for one member of the pair to be attached to the substra- Plate Explanation Figure 1: A copulating pair of Mitra idae 15m underwater off Point Loma, California. The female is depositing a clutch of egg capsules. The male is the smaller member of the pair, and is attached to the right side of the female’s shell. Figure 2: Mitra idae exhibiting grouping behavior Tue VELIGER, Vol. 14, No. 2 [CuHEss « RosENTHAL] Figures /, 2 Vol. 14; No. 2 tum. Under such conditions, it would seem that only with a firm hold on the bottom could the snails maintain position and complete copulation. Length of female (mm) 10 20 30 40 50 Length of male (mm) Figure 5 The size relationship between males and females in 58 copulating pairs of Mitra idae. The pairs were measured in the subtidal area off Point Loma, California, during June, 1970 @ = 1 pair ap == 2 jonny In mating pairs, the female Mitra idae was larger than the male (Figure 5). The mean shell lengths for copu- lating pairs were 51mm and 35mm for females and males, respectively. One mating pair that we observed consisted of a 13mm male and a 15mm female. This was the smallest pair seen during the entire study and yet it had the same female-male size relationship observed in larger mating pairs. CATE (op. cit.) also noted this size relationship for copulating pairs of M. idae. ROSENTHAL (1970) mentioned a similar size selection for copulating THE VELIGER Page 173 pairs of Kelletia kelletii (Forbes, 1850).'The mechanisms involved in the selection of gastropod mates according to shell size are unknown. It is possible that pair selection is made during “grouping” activities (Figure 2), where as many as 11 M. idae have been observed clustered together at one time. There are several possible advantages for a female to pair with a smaller male. Since copulation commonly occurs simultaneously with egg deposition and feeding, a larger female is able to move about more freely while searching for suitable substrata or food. Also, a smaller male is less resistant to water movement, thus allowing the female to hold position more effectively in the surge swept habitat. Cate (op. cit.) observed that a large individual of Mitra idae exuded a cloud of clear mucus and developed a mucus “bubble sac” which attracted smaller individuals. Although we saw no “bubble sac,” we did notice that copulating and spawning females emitted mucus. If a chemical attractant or pheromone exists in the mucus, it apparently continues to be effective after initial pairing, since there were often additional M/. idae crowding around a copulating pair. Occasionally, a second male would mount another in a “piggy back” fashion prior to or during copulation (Figure 3). In similar observations on Olivella biplicata (Sowerby, 1825), Epwarps (1968) noted that males were attracted to, and followed recently deposited mucus trails of sexually ready females. He also observed that a second male would occasionally attach to another that was already copulating. On one occasion in the laboratory, 2 male M. idae consecutively copulated with a female as she was laying a cluster of egg capsules. In each instance, however, neither male partner was with her for more than 24 hours. On no occasion did we see more than one male copulating with a female at the same time. In contrast, a female chestnut cowry, Cypraea spadicea (Swainson, 1823) was observed in the laboratory copulating simultaneously with 3 male C. spadicea (Chess, unpublished data). SPAWNING BEHAVIOR anp FECUNDITY Spawning females were observed at a depth of 18m off Point La Jolla, California, on 8 May 1969. During weekly dives in 1970 we sighted copulating pairs of Mitra idae as early as 24 February; but no spawning was ob- served until 3 June 1970. The reason for the lag between initial copulation and egg deposition is unknown. Laboratory studies were initiated on 8 June 1970. Sixty Mitra idae, ranging in length from 30 mm to 72 mm were Page 174 THE VELIGER Vol. 14; No. 2 collected from 15 m of water off Point Loma and placed into water tables containing 17.0° C sea water. Seven days later 2 females began ovipositing and 3 other pairs were copulating. Spawning continued in subtidal and labora- tory situations during June and early July; however, by 20 July 1970 copulation and egg deposition had ceased altogether. After spawning activities had terminated in the field, M/. idae became more difficult to find, apparent- ly assuming more cryptic habits. During the entire period of observation, water tempera- ture in the laboratory aquaria ranged between 16.0° C and 17.5°C, while field bottom temperatures varied be- tween 9.0° C and 13.0° C. The synchronous termination of reproductive activities in both field and laboratory situ- ations (despite a 3.0° C to 8.5° C temperature variation) suggests the possibility that factors other than temperature influence reproductive behavior in Mitra idae. Orton (1920) indicated that most marine invertebrates seem to require higher than normal temperatures for spawning. RosENTHAL (1970) found that Kelletia kelletii which were maintained in laboratory tanks commenced spawn- ing during the same month as did members of this species inhabiting the subtidal area, despite a 4.0° C to 5.0°C difference in temperature. Based on laboratory observa- tions, Cate (1968) suggested a “relationship between the timing of mating action in M. idae and the exact hour of local high tides.” However, we observed that M. idac copulate and deposit egg capsules in the laboratory during all hours of the day or night, irrespective of the local tide conditions. Mitra idae have been observed laying egg capsules on a variety of substrata in the subtidal area. Rocks, discarded mollusk shells, and dead holdfasts of kelp plants were uti- lized most often by ovipositing females. In the laboratory, egg capsules were deposited on rocks, bricks and the sides of the fiberglass water tables; however, pieces of glass which were placed into these same water tables were not utilized. Subtidal areas with vertical relief appeared to be the most frequent sites of egg capsule deposition off Point Loma. At no time did we find M. idae depositing egg capsules on the sand. Mitra idae were frequently seen laying adjacent to or among egg capsules deposited earlier by conspecifics. Egg capsules from different females are often distinguishable because capsule size varies proportionally with the size of a laying female (Figure 6). On one occasion we ob- served the egg capsules of M. idae, Kelletia kelletu, Shas- kyus festwuus (Hinds, 1844) and the egg mass of the tectibranch Navanax inermis (Cooper, 1862) attached to an eroded shell of Astraea undosa (Wood, 1828). 'The possibilities exist that either A. undosa shells are very desirable as a substratum for ovipositing, or that the Capsule length (mm) 60 Length of female (mm) 40 80 Figure 6 The relationship of female shell length to egg capsule height (correlation coefficient = 0.91) occurrence of one egg capsule acts as a stimulus, either chemically or tactually, for further egg laying by other gastropods. D’Asaro (1966) found that sometimes 2 or more females of different species of Thais would add cap- sules to a common egg mass. ROSENTHAL (1970) indicated that spawned egg capsules of K. kelletu may act as additi- onal stimuli to other mature females which encounter these capsules on the substratum. The determination of egg clutch size in the field was difficult because M. idae tends to lay adjacent to egg capsules deposited previously by conspecifics. In one instance, however, 250 egg capsules of similar size were found in a cluster. A lone female was within this cluster and we believe that all of the egg capsules were laid by this one individual. In the laboratory, a single female M. dae deposited 91 egg cap- sules in 4 days. Another female (72 mm) laid 32 capsules in less than 24 hours. Although our data indicate that larger ovipositing fe- males have higher fecundity than smaller females, we could not determine the total number of capsules depos- ited by these different sized females. The relationship of ovipositing-female shell length to egg capsule height was linear with a correlation coefficient of 0.91 (Figure 6). A 72mm female with 8.0mm capsules and an 11 mm female with 2.0 mm capsules were the extremes for this relationship. Most ovipositing females were 40 to 55 mm Tue VELIcER, Vol. 14, No. 2 [Cuess « RosENTHAL] Figure 3 Figure 3: Two male Mitra idae attached in tandem to a larger ovipositing female. In the center foreground a part of an opistho- branch egg mass is visible. Tue VELIcER, Vol. 14, No. 2 [CHEss « RosENTHAL] Figure 4 Figure 4: Egg capsules of Mitra idae deposited adjacent to the sea anemone Corynactis californicus (Carlgren, 1936). Individual ova can be seen through the transparent capsule wall. Vol. 14; No. 2 THE VELIGER Page 175 16 — i) ee) Number of females 10 20 30 40 50 60 70 Shell length (mm) Figure 7 The size-frequency distribution of 58 ovipositing Mitra idae measured underwater during June, 1970 in shell length (Figure 7). The number of eggs per cap- sule varied between 945 eggs from a 7.5 mm capsule, and 77 eggs from a 2.0 mm capsule. This relationship was also linear, with a correlation coefficient of 0.83 (Figure 8). The eggs ranged between 0.175 and 0.200 mm in dia- meter, regardless of capsule height. Large ovipositing fe- males deposit larger capsules which, in turn, contain more eggs than the capsules of smaller females. EGG CAPSULES anp DEVELOPMENT The egg capsules of Mitra idae are flattened, elongated ovoids which vary in height from 2.0 to 8.0mm. The capsules are transparent (Figure 4) ; thus permitting an observer to follow total development of the embryos and larvae within a specific capsule without destroying or disturbing it. From 17 June until 29 July 1970, 3 separate clusters of egg capsules were studied in the laboratory to determine the rate of larval development and hatching time. The water temperature in the laboratory varied between 18.8° C and 17.5° C during the entire period of development. Height of capsule (mm) 0 200 400 600 800 1000 Number of eggs per capsule Figure 8 The relationship of the number of eggs within a capsule to the capsule height (correlation coefficient = 0.83) Page 176 THE VELIGER Vol. 14; No. 2 Active trochophores were first seen 7 to 8 days after oviposition; veligers appeared in 14 to 15 days; and hatching occurred in 26 to 27 days. As the larvae devel- oped the capsules appeared to darken, approaching a medium brown just prior to hatching. OsTERGAARD (1950) found that egg capsules of Mitra auriculoides (Reeve) “contained embryos in an advanced veliger stage, the coloring of which imparted a pale brownish tinge to the capsule.” The veligers of M. idae become extremely ac- tive prior to hatching. The free-swimming veligers leave the egg capsule by way of an opening at the top of each capsule. The opening is created by the disintegration of a proteinaceous plug that dissolves as the embryos reach the hatching stage. ACKNOWLEDGMENTS We would like to thank Drs. E. S. Hobson and J. B. Pearce, Bureau of Sport Fisheries, U. S. Fish and Wildlife Service for their critical review of this manuscript. Special appreciation is extended to Dr. Reuben Lasker for pro- viding laboratory facilities at the Fishery-Oceanography Center in La Jolla, California. Literature Cited Cate, JEAN McCreery 1968. Mating behavior in Mitra idae MELvILL, 1893. The Veliger 10 (3): 247 - 252; 8 Text figs. (1 January 1968) D’Asaro, Cuarzes N. 1966. The egg capsules, embryogenesis, and early organogen- esis of a common oyster predator, Thais haemastoma floridana (Gastropoda; Prosobranchia). Bull. Mar. Sci. 16 (4): 884 - 914 Epwarps, Datias Craic 1968. Reproduction in Olivella biplicata. 10 (4): 297 - 304; plt. 44; 3 text figs. McLean, JAMES HaMILTON 1969. Marine shells of Southern California. Los Angeles County Mus. Nat. Hist., Sci. Ser. 24, 104 pp., illust. (October 1969) The Veliger (1 April 1968) Orton, JoHN H. 1920. Sea temperature, breeding and distribution of marine animals. Journ. Marine Biol. Assoc. U.K. 12: 339 - 366 OSsTERGAARD, JENS MaTHIAS 1950. Spawning and development of some Hawaiian marine gastropods, Pac. Sci. 9: 110 - 136; 42 text figs. RosENTHAL, RicHarp J. 1970. | Observations on the reproductive biology of the Kel- let’s whelk, Kelletia kelletii (Gastropoda: Neptuneidae) . The Veliger 12 (3) : 319 - 324; plts. 48, 49; 4 text figs. (1 January 1970) Vol. 14; No. 2 THE VELIGER Page 177 Homing Behaviour and Population Regulation in the Limpet Acmaea (Collisella) digitalis BY PAUL A. BREEN Department of Zoology, University of British Columbia, Vancouver 8, British Columbia, Canada ' INTRODUCTION LIMPETS THAT ARE EXPOSED to air during part of the tidal cycle usually remain immobile during that period. In several species of Acmaea, limpets are reported to return to a home site in which they remain at low tide (WELLs, 1917). Such behaviour may assure the limpet protection from desiccation. Several authors have studied homing behaviour in Acmaea digitalis Rathke, 1833, which lives high in the in- tertidal zone of exposed rocky shores on the Pacific coast. Frank (1964) found that marked individuals remained within small areas for long periods of time, and termed such a small area a “home range.” Although Franx (1965) reported that strict homing does not occur, MILLER (1968) found that 25% of the limpets he observed showed a ten- dency to return to a home site. GaLBraiTH (1965) found that 54% homing occurred in 26 A. digitalis watched for 7 days. Mitiarp (1968), studying the behaviour by which A. digitalis forms aggregations or “clumps,” reported that half the original limpets of a clump remained within the clump after a month. Different procedures were used by each of these authors to study homing, which might par- tially account for differences among their results. It is of interest that some individuals in the studies cited above show homing behaviour while others do not. Frank (1965) suggests that homing may be a response to favourable local conditions: “Behaviour evidently is also involved in regulating abundance, probably in an interaction with space and food. As long as their preferred habitat is not saturated, limpets tend to remain where they are.” He also found that when limpets were arti- ficially crowded on a part of the shore, emigration from that part was increased. This indicates that individuals may respond to less favourable local conditions by ceasing to home, thus tending to migrate away. ' Present address: Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada. Frank (1965) further suggests that differences among individual tolerances of local conditions might buffer such a system of local regulation of density. At any level of density, and hence at any level of local conditions, some limpets would be tolerant, and would show homing; others would be intolerant, and so would not show homing. Deterioration of conditions would result in a higher pro- portion of non-homing limpets, and this might tend to reduce local density. A similar hypothesis is suggested by Lomnicxr (1969), who found that land snails, Helix pomatia Linnaeus, 1758, can be divided into 2 groups. Some snails are quite mobile and are usually found on the surface; others are less mo- bile and are usually beneath the surface. Lomnicki suggests that the more mobile snails are the “excess” in relation to local resources. An increase in the proportion of mobile snails might tend to reduce local density to the level which can be supported by the habitat. The purpose of this study was to examine the hypo- thesis that local regulation of density can occur through changes in homing behaviour of Acmaea digitalis. The study was carried out in several stages near Port Renfrew, on the west coast of Vancouver Island. OCCURRENCE or HOMING To determine whether homing was demonstrated by in- dividual Acmaea digitalis at Port Renfrew, 40 limpets within a small area were individually marked in May, 1969. Small printed numbers on adhesive plastic were obtained from the W. H. Brady Co., which manufac- tures them for use in marking electrical components. A number was placed on the posterior dorsal portion of the shell and covered with 2 coats of an acrylic resin known as “Dekophane.” The original position of each limpet was recorded on a sketch map of the area, and its posi- tion was again recorded on 11 subsequent days at low tide. Page 178 Twenty-six limpets were seen in their original location at every observation, 5 changed position once and 9 changed position more than once. Limpets which did not change position appeared to have moved away and re- turned during high tide, because 22 of these limpets were in small clumps of up to 10 animals, and the relative posi- tions of limpets within these clumps changed. It was not possible to observe the marked limpets during their feeding periods away from the homesite: When ob- servations were made underwater during day-time high tides, all the limpets were seen in their shelter sites. Feeding presumably occurred during night high tides, when it was not possible to make observations. It is not possible to test homing in Acmaea digitalis by removing a limpet from its shelter site, placing it nearby and observing whether it subsequently returns. It is shown below (Table 10) that a high proportion of limpets that were removed from their sites and immediately replaced in the site migrated away. Removal appears to cause a disturbance which destroys, temporarily at least, the hom- ing behaviour. It was concluded that homing behaviour is demon- strated by some individual Acmaea digitalis at this loca- tion. IDENTIFICATION oF TWO BEHAVIORAL TYPES The hypothesis which was being tested predicted that 2 types of limpets would be found: namely those that were tolerant of local conditions and showed homing, and those that were intolerant and did not show homing. Two large samples, each of which comprised all the limpets found within a defined area, were marked in- dividually as described above. On each area a grid sys- tem was established so that positions of individuals could be described. On the first area, 28 grid squares were marked on the rock by drilling holes 20 cm apart. On the second area, all limpets were found in 30 small depressions in the rock, in which clumps were formed. These depres- sions were numbered and used to describe positions of individual limpets. Each sample was observed for 6 consecutive days. Each day’s observation included the location at which each limpet was found and the number of limpets with which it was clumped. A clump was defined as 4 or more limpets grouped in such a way that none was farther than 2 cm from another. To avoid confusion between changes in shelter position, as seen between successive days at low tide, and feeding movements, the term “migration” was adopted to describe THE VELIGER Vol. 14; No. 2 the former. A limpet which moved from its shelter site to feed and returned to the same site had not migrated; a limpet that adopted a new shelter site had migrated. Migration could occur in 2 ways: a limpet could migrate to a new grid location, or it could migrate from within an established clump within a grid location to a position outside the clump in the same location. The number of migrations made by each limpet was determined and a distribution of migration frequencies compiled for each sample. These are seen in Tables 1 and 2 for the first and second samples respectively. In both samples, there were more limpets that did not migrate at Table 1 A comparison between the number of limpets in each category of migration frequency and the expected Poisson distribution, which was calculated from the mean number of migrations per limpet per day. These data were ob- tained from the first sample of marked limpets, from June 5 through June 10, 1969 Number of Number of Number of migrations limpets observed limpets expected 0 56 49.28 1 19 28.53 2 8 8.26 3 4 1.59 4 1 0.23 5 0 0.03 Total 88 87.92 X? in the test for Goodness of Fit = 4.94; significant at a = 0.05, Gh ig == tl Table 2 The number of limpets in each category of migration frequency, and the expected Poisson distribution. These data were obtained from the second sample of marked limpets, from August 11 through August 16, 1969 Number of Number of Number of migrations limpets observed limpets expected 0 173 145.45 1 24 61.49 2 16 13.02 3 2 1.82 4 4 0.19 5 3 0.02 Total 222 221.99 X? in the test for Goodness of Fit = 15.22; significant at a = 0.001, dais: Vol. 14; No. 2 all than in any other category, and there were progres- sively fewer limpets in each category of higher migration frequency. If all limpets were equally likely to migrate on a given night, and if the probability of any limpet migrating were not affected by whether or not it had migrated on previ- ous nights, then the distribution of migration frequencies would follow a Poisson distribution. This situation might occur if migrations were caused by local, random stimuli, or if limpets had an innate tendency to migrate at random intervals. In such a situation, the pattern of migrations would have little importance with respect to local regu- lation of density. If the observed distribution of migration frequencies were not in accord with the Poisson distribu- tion, however, it would indicate that limpets were not all equally likely to migrate, or that previous migrations al- tered the probability of a limpet migrating on a given night. Table 3 The numbers of limpets in each category of migration frequency. These data were collected during the periods indicated below, from the first sample of marked limpets in 1970 Number of limpets observed wn [e} ° ane g Loa ae g ~@ ES & 8 19 Qn a On STR) -Q v=! 6 2 o g no ES b AB GS Bel Sees (A fe om < Ss eB 0 35 72 63 73 76 1 9 15 6 6 19 2 5 10 11 11 12 3 1 3 5 5 7 4 1 0 0 0 0 Total 51 100 85 95 114 x2 4.50 12.05 26.63 29.91 13.90 The observed distributions were compared with the expected Poisson distributions by means of the Chi squared (X?) test for Goodness of Fit. These comparisons are also shown in Tables 1 and 2. Both observed distributions were significantly different from the Poisson in the same way. More limpets than expected did not migrate at all, fewer than expected migrated only once and more than expected migrated more than once. In 1970, observation of the first marked sample was continued in an experiment to be discussed below. Five further sets of similar observations were obtained (Table 3). These all show a similar pattern of deviation from the Poisson. THE VELIGER Page 179 Although these results were in agreement with the pre- diction made from the hypothesis being tested, namely that a tendency toward two behavioural types would be found, there were alternate possible explanations for the results. If the migration behaviour of small limpets differed from that of large limpets, deviation from the Poisson might occur. This idea was discounted immediately be- cause all limpets on the first area were approximately the same size: between 1.50 and 2.00 cm. Second, if limpets found in small clumps behaved dif- ferently from those in larger clumps, this might also pro- duce the observed deviation from the Poisson. This was tested in each sample by making an arbitrary division between “large” and “small” clumps, so that roughly half the limpets fell into each category. The data were divided according to the size of the clump in which each limpet was initially found. The distributions of migration frequencies from large and small clumps were then com- pared in each sample by means of the X? test for inde- pendence of samples. These comparisons are shown in Tables 4 and 5. In neither sample was there a significant difference between the two distributions of migration frequencies. Table 4 A comparison between the migration frequency distribu- tions of limpets initially found in large (10 or more limpets) and small (less than 10 limpets) clumps. These data were obtained from the first sample of marked limpets, from July 23 through July 27, 1970 Small Clumps Large Clumps wn n n n ey (e) fe} ~ ~ ~ 2 %, s ah ae 4 BE 3 2B Be BFE CEE Bee ee 0 = fe fey A _ E S| Eo a) Zo ij 7 wa) 7 Oo S 0 38 42.67 38 33.33 1 12 10.67 7 8.33 2 8 6.74 4 5.26 3 6 3.93 1 3.07 Total 64 64.01 50 49.99 X? in the test for independence of samples = 3.73; not significant aya = OWS, his = il A third possibility was that the period of observation was too short. The probability that a limpet would migrate on a given night might be altered by whether or not it had migrated in the previous few days, but such bursts of migration activity might still be independent of activitv Page 180 THE VELIGER Vol. 14; No. 2 Table 5 A comparison between the migration frequency distribu- tions of limpets initially found in large (15 or more limpets) and small (less than 15 limpets) clumps. These data were obtained from the second sample of marked limpets, from August 11 through August 16, 1969 Small Clumps Large Clumps Se al ge eH GEE Bs SHE SES SEE SES EP) Geei (Gib) Soseye Sa 2 & AMS) ZS Aa) 766 0 61 61.56 112 111.44 1 8 8.54 16 15.46 2 6 5.70 10 10.31 3 1 0.71 1 E29 4 2 12, 2 1.93 5 1 1.07 2 1.93 Total 79 79.00 143 142.36 X? in test for independence of samples = 0.39; not significant at = O08, ch ie = il a month previously. In this case, migration could be con- sidered independent over the longer term, and observed deviation from the Poisson would have little importance. This possibility was tested by examining the data pre- sented above in Table 3. These data were collected at intervals over 6 months, and the total number of observed ‘Table 6 The number of limpets in each category of migration frequency, and the expected Poisson distribution. These data have been combined from Table 3 Number of Number of Number of migrations limpets observed limpets expected 0 16 6.95 1 8 12.18 2 3 10.65 3 2 6.22 4 4 2.72 5 3 0.95 6 2 0.28 7 2 0.07 Total 40 40.02 X? in the test for Goodness of Fit = 33.69; significant at a = 0.001, alLig = & migrations of 40 limpets could be determined. The re- sulting frequency distribution, which contained 15 pos- sible migration categories, was compared with the Poisson (Table 6). This distribution was not in accord with the Poisson, and the pattern of deviation was similar to that seen in the component sets of observations. Thus there appeared to be 2 behavioural types of limpets. Some tended not to migrate at all, while others tended to migrate many times. Fewer limpets than ex- pected migrated only once during periods of observation. This behaviour appeared consistent over long periods of time, and could not be explained by differences in behav- iour associated with size or clump size. It was concluded that 2 behavioural types of limpets, homing and non- homing, had been detected. This supported the hypo- thesis which was being tested in this study. RELATION Between DENSITY AND HOMING BEHAVIOR If homing were a response to favourable local conditions, and non-homing to unfavourable conditions, then the proportion of non-homing limpets would be expected to increase if local conditions deteriorated. It was reasoned that increased density within an enclosed area would re- sult in less favourable local conditions within the area, and thus a positive correlation between the percentage of non-homing limpets and density was predicted. In February, 1970 the area containing the first sample of marked limpets was enclosed with a fence made from plastic mesh. The mesh was fastened to the rock with screws, and the lower edge sealed with a mixture of fibreglass resin, sand and catalyst. All limpets within the fence were marked or remarked. Two sets of observations were made on the migration behaviour of the marked lim- pets at this natural density. Then limpets from elsewhere were added to the area, increasing density to twice its previous level; and 2 more sets of observations were made. More limpets were added, increasing density to 4 times its original level, and one further set of observations was made. Only the data obtained from those limpets originally present in the enclosure in February are presented. It was found that limpets which were added to increase the density within the enclosure had a significantly higher rate of migration than the original limpets, so these data were not used. A similar observation was made by Lom- nicki (1969), who reported that snails that he added to his study area behaved like the more mobile snail type. Vole 14-,No' 2 GERVEEIGER Page 181 The percentage of limpets that migrated and the mean number of migrations per limpet per day were calculated during each set of observations, and are presented in Table 7. The correlation between relative density (calcu- lated by dividing the number of limpets in the enclosure by the original number in February) and the percentage migrating was r= 0.349, The correlation between rela- tive density and mean number of migrations per limpet per day was r= 0.242. Neither was statistically signifi- cant, which indicated that there was no relation between density and these two measures of migration rate, at least within the experimental range of densities. Table 7 Comparison between relative density and percentage of limpets that migrated during the period of observation, and between density and the mean number of migrations per limpet per day Ty OQ >> a Mt ee Period of 8 Bf g2 ges observation s§ = a5 os § bo I Saas As) oe te Sears Feb. 15 to 133 1.00 31.4 0.127 Feb. 19 April 29 to 125 0.94 28.0 0.146 May 2 June 1 to 290 2.18 23.2 0.113 June 5 June 16 to 283 2.13 28.2 0.162 June 19 July 23 to 561 4.22 33.3 0.149 July 27 The results from this experiment thus seem to contra- dict the hypothesis that local densities can be regulated through changes in homing behaviour. A possible criti- cism of this experiment, however, is that density was progressively increased from early spring to summer. Changes in seasonal conditions may have caused changes in homing behaviour which compensated for the effect of increasing density. From an experiment carried out during the summer of 1969, which will be presented in a subsequent publication, there is evidence that limpets are more conservative in their movements during summer, when warm, dry weather presents dangers in the form of desiccation. Because seasonal conditions may have affec- ted the outcome, this experiment may not have been an adequate test of the hypothesis. HOMING AND LOCAL ENVIRONMENTAL CONDITIONS In the previous experiment it was assumed that increased density would result in less favourable local conditions for the limpets; increased density might be expected to cause decrease in the availability of food and space. The following experiments were carried out to determine whe- ther the proportion of non-homing limpets would increase when food and space were decreased directly. Food availability was decreased directly in two experi- ments, one in 1969 and one in 1970. In these experiments, algae on the rock surrounding a clump of limpets (marked with quick-drying paint) were removed with a wire brush to a distance of 60 cm from the clump. The number of marked limpets which emigrated from the clump was used as a measure of non-homing, and was compared with the number of emigrants from a control clump, around which the algae had not been removed. In each experiment the experimental and control clumps were chosen in areas of similar local topography, just far enough apart that movement of limpets from one to the other would be unlikely. For each clump, the number of marked animals remaining in the clump, the number of emigrants and the distances travelled were recorded. ‘The results from the 1969 and 1970 experi- ments are presented in ‘Tables 8 and 9 respectively. ‘The number of emigrants from the experimental clump was Table 8 The number of limpets remaining, the number of emig- rants and the median distance travelled by emigrants in the experimental (E) and control (C) groups of an ex- periment designed to measure the response of limpets to reduced food levels. Algae were removed from around the experimental group on July 30, August 2, 10, 15 and September 1, 1969 g Sy af Bo 5 eZ ees eee Deke eae 2a Sos E 1, © E Cc July 30 847 0 0 0.0 0.0 August 2 SS: 1 ees) 20.0 16.7 August 10 GS 7/il 6 4 60.0 50.0 August 15 62 62 16 10 105.5 38.0 September 1 5S) ie} 16 14 160.0 92.1 Page 182 THE VELIGER Vol. 14; No. 2 ‘Table 9 The number of limpets remaining, the number of emig- rants and the median distance travelled by emigrants in the experimental (E) and control (C) groups-of an ex- periment designed to measure the response of limpets to reduced food levels. Algae were removed from around the experimental group on June 4 an 5, 1970 € (2) pe 2 =) SY z's 58z o2 ce Ee 3 7] Date Zaks 2 ae sé ERC ESE IEC EC June 4 93 111 0 0 0.0 00 June 5 84 109 3 (0) 42.5 0.0 June 16 46 90 43 18 54.5 45.0 only slightly higher than that from the control in the 1969 experiment, but the emigrants from the experimental clump travelled a greater median distance than those from the control. In the 1970 experiment, the rate of emigration was higher from the experimental clump, al- though the median distances travelled by emigrants from both groups were similar. Availability of space was decreased in an experiment carried out in June, 1969. It was reasoned that by adding limpets to a clump, the space available to the original limpets would be decreased immediately, while there would be no immediate effect on the amount of food present. The number of limpets which emigrated from the clump could, as in the previous experiments, be used as a measure of non-homing, and compared with that from a control clump. Four similar clumps of limpets were marked with quick-drying paint in June, 1969. Two were designated as experimental groups, and 2 as controls. The number of limpets in each experimental group was doubled by the addition of limpets removed from elsewhere. In addition, the effect of removal and replacement on those limpets that were added to the experimental groups was tested. All the limpets in one experimental and one control clump were removed and immediately replaced in the same site. These were then called the disturbed experi- mental and disturbed control groups. The number of original limpets remaining in each clump were recorded the following day, and are presented in Table 10. Few limpets remained in the disturbed groups, while a much higher percentage remained in the undisturbed groups. This indicated that removal and replacement caused a high proportion of limpets to mi- grate from their home sites. In addition, each experi- mental group had fewer limpets remaining than the ap- propriate control group. This indicated that reduced availability of space may have caused a slight decrease in the proportion of homing limpets. Table 10 The initial number of limpets in each of four treatment groups in an experiment designed to measure the response of limpets to crowding, and the number that remained in each group after one day. See text for explanation June 7, 1969 June 8, 1969 Initial number Number of Percentage Group of limpets limpets remaining remaining undisturbed 47 39 82.97 experimental undisturbed 51 50 98.03 control disturbed 52 3 5.76 experimental disturbed 52 7 13.46 control This experiment was repeated in 1970, but was incon- clusive for the following reason. Limpets were added to the experimental groups on the morning of a very hot day. Because limpets that are placed on an area do not move about to find shelter sites, and thus are vulnerable to desiccation, all groups of limpets were splashed with seawater at intervals throughout the day. After the follow- ing high tide nearly all limpets had moved to new posi- tions, in the control groups as well as in the experimental groups. This made the results inconclusive. Although these experiments tended to be inconclusive, it appears that sudden decreases in food levels may result in a decreased proportion of homing limpets, and that sudden crowding may have the same effect. DISCUSSION The hypothesis that local populations of Acmaea digitalis can be regulated by changes in individual homing behav- iour was examined in this study. Homing was found to be present in individual A. digitalis at Port Renfrew, and there appeared to be a tendency toward two behavioural types with respect to homing. Some limpets returned to a home site consistently, while others were observed to Vol. 14; No. 2 wander over the study areas. The behaviour seemed to persist during 6 months of observation. Although homing appeared to be modified as a result of artificial disturbances, it was not conclusively demon- strated that changes in individual behaviour occur as a result of feedback from population density. There is a striking similarity between the observations of 2 behavioural types in Acmaea digitalis and the situa- tion reported by Lomnicx1 (1969) in Helix pomatia. The cause of 2 types of behaviour in H. pomatia remains un- explained, although Lomnicki suggests that behaviour is determined by local density and local resources. KREBS (1970) has shown that levels of aggression in the small rodent Microtus change as population levels change; and he suggests that such changes may be important in regu- lating local densities of Microtus. WELLINGTON (1964) has demonstrated that differences among activity levels of members of a moth population contribute to the stability of the population in an unstable, heterogeneous environ- ment. These studies underscore the need to consider vari- ability in the behaviour of individuals within a population. Further study is needed to determine the basis of observed behaviour patterns in Acmaea digitalis, and to evaluate their importance to regulation and stability in population of this species. ACKNOWLEDGMENTS This work formed part of a Master’s degree programme carried out under the guidance of Dr. J. Robin Harger, whom I wish to thank for his insights and critical advice. I am also deeply grateful to Dr. John Stimson for his encouragement during the study, and to Dr. N. J. Wilim- THE VELIGER Page 183 ovsky, who kindly permitted me to work at the Marine Biological Station at Port Renfrew. This study was supported by a grant from the National Research Council of Canada to Dr. Harger. Literature Cited FRANK, PETER WOLFGANG 1964. On home range of limpets. (899) : 99 - 104 1965. The biodemography of an intertidal snail population. Ecology 46 (6): 831 - 844; 8 figs.; 6 tables Ga.praiTH, Rospert T. 1965. | Homing behavior in the limpets Acmaea digitalis and Amer. Midland Natural. 74 (1): 245 - 246 Amer. Naturalist 98 Lottia gigantea. Kress, Cuartes J. 1970. Microtus population biology: behavioural changes as- sociated with the population cycle in M. ochrogaster and M. pennsylvanicus. Ecology 51: 34 - 52 Lomnick1, ADAM 1969. Individual differences among adult members of a snail population. Nature 223: 1073 - 1074 Miniarp, Caro SPENCER 1968. The clustering behavior of Acmaea digitalis. The Veliger 11, Supplement: 45 - 51; 4 text figs.; 1 table (15 July 1968) Miter, ALAN CHARLES 1968. Orientation and movement of the limpet Acmaea digi- The Veliger 11, Supple- (15 July 1968) talis on vertical rock surfaces. ment: 30 - 44; 18 text figs.; 4 tables WELLINGTON, W. G. 1964. Qualitative changes in populations in unstable envi- ronments. Canad. Entomol. 96: 436 - 451 WEL ts, Morris M. 1917. The behavior of limpets with particular reference to the Journ. Anim. Behav. 7 (6): 387 - 395 homing instinct. Page 184 THE VELIGER Vol. 14; No. 2 Predation of Marisa cornuartetis on Oncomelania formosana Eggs under Laboratory Conditions’ BY LOIS WONG CHI’, LINDSAY R. WINKLER ® anp RUTH COLVIN (1 Text figure) IN THIS ERA SINCE SILENT SPRING any suggestion of biologi- cal control of pests is worthy of investigation. Conse- quently the report from the literature (OLIVER-GONZALEZ, 1956; CHERNIN, 1956; FERGUSON, 1958; RapKE, 1961) that Marisa cornuarietis (Linnaeus, 1758) caused the disap- pearance of the schistosome-bearing snail Bzomphalaria (=Australorbis, Intern. Comm. Zool. Nomencl., Op. 735) glabratus (Say, 1818) in both laboratory and field studies done in Puerto Rico stimulated interest. It was decided to investigate the practicability of applying the same biologi- cal control to the oriental amphibious schistosome-bear- ing snail, Oncomelania. MATERIALS ann METHODS Marisa cornuarietis were reared from stock obtained from Puerto Rico. Initial shipments of the snails all died soon after arrival but the last shipment, after treatment with aureomycin (12 mg to 7 gal.), lived long enough to lay eggs. These eggs hatched in 3—4 weeks and established a thriving colony which reached maturity in about 5 months at a con- trolled temperature of 78° F. Stock snails were kept in one gallon-capacity aquaria supplied with filter, a pump and white gravel substrate to facilitate recovery of the smaller Oncomelania, especially the young. Water cress and filter paper which they consumed in quantity were used as their normal diet. Experimental snails were kept in similar con- tainers. The same food was supplied in all experiments except where specifically stated otherwise. * This investigation was supported by research grants from the National Institute of Allergy and Infectious Diseases, the United States Public Health Service #A1—02705-07 and were conducted in part at Immaculate Heart College, Los Angeles, California. * California State College, Dominguez Hills, California, and * College of the Desert, Palm Desert, California A total of 398 Oncomelania formosana (Pilsbry & Hirase, 1905) young, ranging in size from 2.0 mm to 3.5 mm, were exposed to 68 Marisa for one week and 240 On- comelania eggs were exposed to 37 Marisa. Control tanks contained only eggs or young without Marisa. These young were exposed to Marisa for one week. The eggs, however, were run in several batches, some of which were exposed for one and some for three days. In the experiment designed to establish predation of Marisa during the egg stage, eggs were labeled with copper by soaking them while still in the mud capsules with 1% copper sulfate for 12 hours after which the unbound cop- per was leached out in large volumes of distilled water. After exposure of the eggs to Marisa for three days, the fecal pellets of the latter were collected and developed chemically for copper by incubating them in a 10% solu- tion of sodium acetate to which a few drops of 0.1% ru- beanic acid were added for 24 hours. The fecal pellets were then examined for the intense, dark blue-black color of the rubeanic acid reaction. Control Marisa were ex- posed to a similar quantity of copper-labeled Oncomelania eggs confined in a screened area inaccessible to the Marisa to rule out any possible diffusion effects. A second control without copper or eggs determined the normal control color of the fecal pellets after being treated with rubeanic acid. RESULTS anp CONCLUSIONS Of the 398 Oncomelania formosana young exposed to Marisa (see Table I), 357 (90%) were recovered alive, com- pared to 387 (97%) recovered from the control aquaria without Marisa. There was a small percentage of missing snails the shells of which could not be accounted for in both the experimental and control aquaria. Vol. 14; No. 2 THE VELIGER Page 185 Figure 1 Fecal pellets of Marisa cornuarietis showing spots of black color characteristic of the copper-rubeanic acid reaction indicating Mar- sa’s consumption of copper-labeled Oncomelania eggs. Control pel- lets do not show such black spots. Table 1 Recovery rate of Oncomelania eggs and young when exposed to Marisa over a one-week period ee 32 6 888 3 3 VP be Bo BSS 88 A g§ ES2S g (e) x fo) Se Spies Q 9 ZX ZOvs Ze 2 TEsT Marisa and Oncomelania eggs 37 240 eggs 128 eggs 53.3 ConTRoL Oncomelania eggs — 184eggs 174 eggs 94.6 TEsT Marisa and Oncomelania young 68 398young 357 young 89.7 ContTROL Oncomelania young — 398young 387 young 97.2 The difference in number of recovered young was not sufficiently different to suggest more than the possibility of a slight adverse influence (Table I) due to the presence of Marisa in the tank and is not considered to be signifi- cant. Of the total of 240 Oncomelania eggs exposed to Marisa, 121 eggs (53%) were recovered in contrast to 174 out of 184 (95%) in the controls. This indicated that Marisa had decreased the number of eggs to a significant degree, at least under laboratory conditions. However, when the ex- posure was increased to three days the destruction of eggs increased only to 29% as against 61% in the control aquaria. A method of simple calculation showed that the expected percentage without the influence of Marisa (x/61%=53%/95%) would be 33%. Subtracting 29% from this figure gives us the influence of Marisa in this ex- periment or 4% which can hardly be considered signifi- cant. Perhaps the eggs of Oncomelania possess an odor for a time which helps Marisa locate them, but which is lost after a short time, thus protecting the survivors. In order to determine if the Marisa were actually eating the eggs rather than contributing to their destruction solely by mechanical disruption of their nesting sites On- comelania eggs labeled with copper were exposed to Marisa and the copper was subsequently detected in the fecal pellets by the sensitive rubeanic acid technique. Of a total of approximately 500 fecal pellets so treated, 21 showed spots of the dark blue black color characteristic of the above reaction (Figure 1). None of the controls showed such spots. In order to obtain a clearer understanding of any pos- sible inhibitory effect of Marisa on Oncomelania, the two species of snails (120 adult O. formosana with 11 adult and 100 young Marisa) were maintained together for 5 months in a three gallon capacity aquarium with mud and rock banks to create an amphibious environment. Marisa were noted to constantly disrupt the mud bank inhabited by Oncomelania, causing mechanical disturbance which would be expected to affect adversely the laying and hatch- ing of the eggs of the latter. At the end of 5 months only one young and 47% of the original adults were recovered as compared to 20 young and 78% of the 120 adults in the control tank lacking Marisa. On the basis of these results it appears that Marisa would be less effective in controlling Oncomelania than Biom- phalaria. The degree of competition does not include the consumption of a common food and relies solely on a pre- datory or disruptive relationship or both. This relation- ship might be sufficient, however, to replace or noticeably reduce the population of Oncomelania in time as has been the result with Biomphalaria (PALMER et al., 1969; Ruiz- TIBEN e¢ al., 1969; Jobin, Berrios et al., 1970; JoBIN, FEr- Guson et al., 1970). Such influence could be expected and Page 186 evaluated only after ecological equilibrium has become established in a field situation and is beyond the scope of this work. SUMMARY After establishment of a colony of Marisa cornuarietis in the laboratory, the aquatic young and egg stages of On- comelania formosana were exposed to the former under varying conditions. Marisa was found to be especially de- structive to the eggs. By labeling the Oncomelania egg capsules with copper and subsequently detecting the copper in the fecal pellets of Marisa it was determined that the latter consumed the eggs of Oncomelania, though perhaps only coincidental to other activities. The young of Marisa were noted to be more predacious than adults. ACKNOWLEDGMENT The authors wish to express their appreciation to Dr. Frederick Ferguson for supplying the adult snails from which the colony was established and for his suggestions and encouragement in carrying out this work. THE VELIGER Vol. 14; No. 2 Literature Cited CuHernin, E., E. H. Micuetson « D. .L. AucustIn 1956. The control of Australorbis glabratus populations by the snail Marisa cornuarietis, under laboratory conditions. | Amer. Journ. Trop. Med. & Hyg. 5: 297 - 307 Fercuson, F. EF, J. Outver-Gonzaez & J. R. PALMER 1958. Potential for biological control of Australorbis glabratus, the intermediate host of Puerto Rican schistosomiasis. Amer. Journ. Trop. Med. & Hyg. 7: 491 - 493 Josin, Witu1AM R. & Berrios-DuRAN 1970. Cost of harvesting and spreading Marisa cornuarietis for biological control of Biomphalaria glabrata in Aibonito, Puerto Rico. Bull. World Health Org. 42: 177 - 179 Josin, Wittiam R. & FRepERICcK FE FERGUSON 1970. Control of schistosomiasis in Guayama and Arroyo, Puerto Rico. Bull. World Health Org. 42: 151 - 156 Otiver-GonzaLez, J., P M. Bauman « A. S. BENENSON 1956. Effect of the snail Marisa cornuarietis on Australorbis glabratus in natural bodies of water in Puerto Rico. Amer. Journ. Trop. Med. & Hyg. 5: 290 - 296 Ortiz-Tonez, E. 1962. Damage caused by the snail Marisa cornuarietis to young rice seedlings in Puerto Rico. Journ. Agric. Univ. Puerto Rico 46 (3): 241 - 242 PaLMER, JuAN R., Arpa E. Coin, FRepericK E FERGUSON & WitiiaM R. Josin 1969. The control of schistosomiasis in Patillas, Puerto Rico. Publ. Health Reprts. 84: 1003 - 1007 Ranke, M. G., L. S. Rircuiz « FREDERICK FE FERGUSON 1961. | Demonstrated control of Australorbis glabratus by Mar- isa cornuarietis under field conditions in Puerto Rico. | Amer. Journ. Trop. Med. & Hyg. 10: 370 - 373 Ruiz-Trsen, Ernesto, Juan R. PALMER & FREDERICK EF FERGUSON 1970. _ Biological control of Biomphalaria glabrata by Marisa cornuarietis in irrigation ponds in Puerto Rico. Bull. World Health Org. 41: 329 - 333 Vol. 14; No. 2 THE VELIGER Page 187 Contribution to the Taxonomy of the Muricidae ( Gastropoda : Prosobranchia ) WALTER OLIVER CERNOHORSKY Auckland Institute and Museum, Auckland, New Zealand (1 Plate; 1 Text figure) IN A RECENT PAPER, entitled “Some comments on Cerno- horsky’s ‘Muricidae of Fiji”, E. H. Voxes (1970) re- corded her disagreement with certain points pertaining to the taxonomic treatment of species in “The Muricidae of Fiji’ (Cernonorsky, 1967). This particular paper was presented as a faunal monograph and not a taxonomic revision of the family, and therefore no attempt was made to locate and critically examine all relevant type material. In the meantime, however, the writer had the opportunity to examine some of the types of taxonomically unstable species, and Mrs. Vokes’ paper affords the opportunity to publish relevant notes and at the same time discuss points where disagreement seems to prevail. I wish to point out that in the case of species which are not represented by extant type material and are defined by often ambiguous illustrations in old iconographies, the identity of such spe- cies will be subject to dispute. Very often little factual evidence can be presented in discussions of controversial taxonomic points, and in these cases interpretations should be based on personal opinions. Disagreement between Mrs. Vokes and myself seems to persist on the following points : 1. The type species of Murex Linnaeus, 1758, is Murex tribulus Linnaeus, 1758, by subsequent designation of Gray, 1847. Monrrort’s (1810) designation of M. pecten Montfort, 1810 (non Lightfoot, 1786) is not eligible under article 69(a) (iv) of the Code of the ICZN, since Montrort (of. cit.) did not synonymize his new species with M. tribulus Linnaeus; his description of M. pecten is sufficient evidence that Montfort believed his new species to be distinct from M. tribulus Linnaeus. 2. Only detailed population studies can confirm the validity of Murex scolopax Dillwyn, 1817, as a biospecies. The characters of buttressed varices and presence or lack of intercalary spines are variable features in species of the M. tribulus complex. I tend to agree with Dopce (1957) rather than Vokes that Murex nigrispinosus Reeve, 1845, is a colour form with dark-tipped spines of M. tribulus Linnaeus. 3. I agree with Vokes in considering Murex penchinati Crosse, 1861, to be a distinct species and not a form of either M. brunneus Link, 1807, or M. huttoniae B. Wright, 1878. The holotype of M. penchinati (Figure 6) is in the I 100 uu Figure 12 Radula of Chicoreus penchinati (Crosse). Rachidian and lateral tooth. Hazlewood Island, Queensland. British Museum (Natural History), London, and measures 40.6 mm in length and 21.4 mm in width; the colour is not bright pink as presumed by Vokes, but light fawn with only a trace of pink on the early whorls. The intervarical nodes are longitudinally oriented nodules upon the spiral cords which have the appearance of slender axial ribs, one smaller, the other larger, on the earlier whorls; the columella is smooth, and the outer lip has 12 denticles, with the inner 10 denticles grouped in pairs. Originally described from the Ryukyu Islands and reported from Nagasaki by DuNxKER (1882), we have examined speci- mens of Chicoreus penchinati from Hazlewood Island, Whitsunday group, Queensland, Australia (leg. R. Carey). The Queensland specimens (Figure 7) have 2 to 3 longi- tudinally oriented rows of intervarical cordal nodes in comparison to the single swollen node of C. brunneus Page 188 iE WELIGER Vol. 14; No. 2 (Link), and the colour is light fawn or light yellowish- brown with a slight pink hue. The species has been illus- trated by RipprncaLe « McMicwHaet (1961, plt. 12, fig. 10) under the name Chicoreus huttoniae Wright. 4. I do not consider Murex aculeatus Lamarck, 1822, to be either a primary or secondary homonym of Aranea aculeata Perry, 1811. Originally described in different genera, M. aculeatus Lamarck belongs in the genus Chi- coreus Montfort, 1810, whereas A. aculeata is assigned to Murex s. str. Article 20 of the Code of the ICZN is applicable only to genus-groups and not to species-groups, and Muricites Schlotheim 1820 (= Gesner, 1758), although an un- available name, would preoccupy any subsequent identical specific name in combination with the genus-group Muri- cites. Muricites aculeatus Schlotheim, 1820, does not pre- occupy Murex aculeatus Lamarck, 1822, as stated by VoKEs (op. cit.). As far as species-group names are con- cerned, even a one-letter difference in the generic name with which the species-group names are in combination, is sufficient to prevent homonymy. Article 57(d) of the Code makes no exception for article 20 or 56(b) in this case. 5. The taxonomy of Murex capucinus Lamarck, 1822 (non Purpura capucina Roding, 1798) is somewhat more complicated due to an error in identification of the La- marckian taxon. According to Rosalie de Lamarck’s anno- tation on the left hand margin of her father’s copy of volume 7 of the “Histoire naturelle des animaux sans vertébres” (see CerNoHOorSKy, 1969), Lamarck had 3 specimens of Murex capucinus in his collection at the time of description. Lamarck’s indicated size for one of his larger specimens was ‘4 pouces’ and ‘9 lignes’ (= 128.2 mm), and only this specimen which bears the registra- tion number 1099/23 and which has been marked as “Type” by a former curator, is in the Muséum d’Histoire Naturelle, Geneva. This specimen, which is a bona fide syntype, is here designated as the lectotype of Murex ca- pucinus Lamarck, 1822; the specimen measures 124.7 mm in length, and it is the same specimen for which LAMARCK (1822) gave dimensions and on which he based his de- scription. At first glance the frondless varices give the impression of a specimen of M. capucinus of authors, but closer examination shows the type to be a very worn speci- men which is twice the size of M. capucinus, dark brown in colour, with darker brown, numerous and finely nodu- lose spiral cords on whorls with additional smaller spiral threads between the main cords; the body whorl has a large intervarical swelling with an indication of a much smaller one next to it; the aperture is white and the outer lip has 12 small denticles. The lectotype of Murex capucinus Lamarck is probably a large and worn specimen of M. torrefactus Sowerby, 1841, but certainly not the M. capucinus auctt. for which the name M. permaestus Hedley, 1915 is available. Voxes (1964) considered Purpura capucina Réding, 1798 to be probably the species Murex adustus Lamarck, 1822 (= M. brunneus Link, 1807), whereas VoxeEs (1970) suggests that Purpura capucina Réding is a composite species consisting of Murex triqueter Born, 1778 and M. quadrifrons Lamarck, 1822. My own interpretation of the figure in Martini (1777, plt. 105, fig. 994) was M. capu- cinus auctt., based on Martini’s locality record of “East Indies,” which would exclude the West African M. quad- rvifrons, and on the author’s statement that the specimen figured in plate 105, figure 993 came from the Bolten collection and his own (figures 993 and 994 were com- bined under one heading description by Martini). To maintain taxonomic stability and to prevent Murex capu- cimus Lamarck, 1822 from being utilized as a senior synonym of M. torrefactus Sowerby, 1841, it is desirable that a figured lectotype be designated in the absence of Plate Explanation Figure 1: Murex capucinus Lamarck, 1822. Lectotype, MHNG 1099/23. Locality unknown (“Océan indien” on label). Length 124.7 mm [MHNG = Muséum d’Histoire Naturelle de Genéve] Figure 2: Murex lignarius A. Adams, 1853. Lectotype, British Mu- seum (Natural History), London, coll. Cuming. West Africa. Length 55.3 mm Figure 3: Murex trigonulus Lamarck, 1816. Syntype, MHNG, 1099/35. Locality unknown. Length 37.4 mm Figure 4: Murex cumingi A. Adams, 1853. Lectotype, British Mu- seum (Natural History), London, 1963817, coll. Cuming. Philip- pine Islands. Length 58.1 mm Figure 5: Murex phyllopterus Lamarck, 1822. Holotype, MHNG, 1099/27. Locality unknown (“Océan indien” on label). Length 83.4 mm Figure 6: Murex penchinati Crosse, 1861. Holotype, British Muse- um (Natural History), London, coll. M. Thomas. Baie de Nafu, iles Liou-Tcheou [= Ryukyu Islands]. Length 40.6 mm Figure 7: Chicoreus penchinati (Crosse). Hazlewood Island, Whit- sunday group, Queensland, Australia (leg. R. Carey). Length 40.7 mm Figure 8: Murex rubridentatus Reeve, 1846. Locality unknown (from REEvE, 1846, plt. 36, fig. 186b) Figure 9: Murex secundus Lamarck, 1822. Lectotype, MHNG, 1099/43/1. Locality unknown (“Océan indien” on label). Length 44.4 mm Figure 10: Homalocantha secunda (Lamarck). Port Hedland, West Australia (leg. G. M. Hansen). Length 25.0 mm Figure 11: Murex uncinarius Lamarck, 1822. Holotype, MHNG, 1099/31. Locality unknown (“Océan indien” on label). Length 24.6 mm [CeERNoHORSKy] Figures / to 11 Tue VELIGER, Vol. 14, No. 2 Vol. 14; No. 2 existing type specimens. In view of the different specific identifications of Purpura capucina Roding by VoKes (1964 and 1970) and CerNnonorsky (1967), Roding’s taxon should be considered a nomen dubium. The confusion between the West African Murex quadri- frons Lamarck, 1822 and the Indo-Pacific M. capucinus auctt. (= M. permaestus Hedley) began with REEve (1845) who considered M. quadrifrons to be only a 4- varicose variant of M. capucinus auctt. Lamarck’s holo- type of M. quadrifrons is in the Muséum d Histoire Natu- relle, Geneva, no. 1099/45; the type measures 70.2 mm in length, and it is the specimen which has been figured by Kiener (1842) on plate 34, figure 1 as M. quadri- frons. Murex lignarius A. Adams, 1853 from West Africa is another synonym of M. quadrifrons Lamarck. The 2 syntypes of M. lignarius (one juvenile and the other adult) are in the British Museum (Natural History), London; the adult syntype (Figure 2), which measures 55.3 mm in length, is here selected as the lectotype of M. lignarius A. Adams, 1853. Although somewhat faded, the specimen is dark brown in colour with traces of the same colour on the columella and outer lip, with 2 intervarical axial nodes, strong spiral cords with | to 2 smaller intermediate threads, a smooth columella and 9 denticles on the outer lip. The lack of a true broad flange on the anterior portion of the varices and the morphological similarity to Chico- reus quadrifrons (Lamarck) suggest a location of Murex permaestus Hedley (= M. capucinus auctt.) in the genus Chicoreus Montfort rather than in Naquetia Jousseaumé. VoKES (op. cit.) considers the illustrations of Ptery- notus (Naquetia) triqueter (Born, 1778) in CERNOHORSKY (1967, plt. 15, fig. 15) not to be this species but to repre- sent Naquetia amanuensis (Couturier, 1907) instead. Cou- TuRIER (1907) described his Murex (Chicoreus) triqueter Born, var. amanuensis as follows: “This variety obtained at Amanu [= Tuamotu Archipelago] differs from the type by the more slender and elongate anterior canal” [transl.]. The variety was not illustrated and the brief diagnosis based on a highly variable single character makes a recognition of a variant as a valid biospecies rather doubtful. Murex trigonulus Lamarck, 1816 also has a slightly more slender and longer siphonal canal than the Fijian specimens of Pterynotus (Naquetia) triqueter (Born) figured by me. The remaining syntype of Murex trigonulus Lamarck (there were originally 2 specimens in the collection according to R. de Lamarck) is in the Muséum d Histoire Naturelle, Geneva, no. 1099/35 and measures 37.4 mm in length (Figure 3). One of the syntypes of Murex cumingii A. Adams, 1853 from the Philippine Islands is almost a replica of the spe- cimen of Pterynotus (Naquetia) triqueter (Born) figured THE VELIGER Page 189 from the Fiji Islands. The syntype under discussion is in the British Museum (Natural History), London, no. 1963 817 and measures 58.1 mm in length and 26.1 mm in width. It is a specimen of M. triqueter Born with the usu- al creamy-white and brown transverse bands, 4 narrow and nodulose intervarical axial ribs on the body whorl and 3 on the penultimate whorl; the columella is smooth, the outer lip has 14 denticles and a small square label is attached to the wall of the outer lip; the upper part of the ventral side of the body whorl is etched, having at one stage been attached with glue to a tablet. This speci- men is here selected as the lectotype of Murex cumingi A. Adams, 1853 (Figure 4). It is my opinion that both M. trigonulus Lamarck and M. cumingu A. Adams are con- specific with M. triqueter Born and in case of a specific or infraspecific split would have chronological priority over M. triqueter var. amanuensis Couturier. 6. Nomenclatural confusion may arise through equi- vocal interpretations of often indifferent figures in old iconographies. Vokes (of. cit.) interprets the Martini figures (1777, plt. 106, figs. 995, 996) on which Purpura carneola Roding, 1798 and P. elongata Link, 1807 were based, as the species Murex saulit Sowerby, 1841; the author commented on the striking features of pink aper- ture and light brown colour of the species represented by Martini. Martini (1777), however, described the species as light brown with dark spiral bands and traces of a rosy colouring in the hollow digitations [transl.]. This descrip- tion does not fit either M. torrefactus Sowerby, as pre- sumed by Tomiin & WinckwortH (1936) or CERNO- HORSKY (1967), nor M. saulit Sowerby, 1841 as suggested by Vokes (op. cit.), but is a perfect diagnosis for the species M. palmarosae Lamarck, 1822 (= Triplex folt- atus Perry, 1810). 7. I concur with Voxes (op. cit.) that Murex phyllo- pterus Lamarck, 1822 is not conspecific with M. pinnatus Swainson, 1822 (== Purpura alata Roding, 1798), but at the same time I disagree with her suggestion that M. phyllopterus is conspecific with M. rubridentatus Reeve, 1846. Lamarck’s holotype of M. phyllopterus (the only specimen he owned according to R. de Lamarck) is in the Muséum d’Histoire Naturelle, Geneva, no. 1099/27 (Fig- ure 5). The type measures 83.4 mm in length, is creamy- white in colour, the 2 intervarical axial ribs are short, angulate, and extend over only 3 spiral cords, the colum- ella is smooth and the outer lip has 8 denticles + 1 small intercalate one. Murex phyllopterus Lamarck and M. rub- ridentatus Reeve (Figure 8) are in my opinion not only different species but belong in different subgenera. Despite Vokes’ claim that Murex pinnatus Swainson (= Purpura alata Roding) is non-denticulate, speci- Page 190 THE VELIGER Vol. 14; No. 2 mens examined show 9 to 10 small denticles on the outer lip, a feature clearly depicted in figures of M. pinnatus in major iconographies. 8. A synonymic list does not follow any prescribed rule and the compilation of a synonymy is every author’s indi- vidual responsibility. Murex uncinarius Lamarck, 1822 was placed in the synonymy of Pterynotus elongatus (Lightfoot, 1786) purely on the basis of Lamarck’s figure citation; in the discussion of the species it was clearly pointed out that this particular case was an instance where cited figures may be in conflict with the actual type. The holotype of M. uncinarius Lamarck (only a single speci- men was in the collection according to R. de Lamarck) is in the Muséum d'Histoire Naturelle, Geneva, no. 1099/31 (Figure 11). The type measures 24.6 mm in length, the last 2 varices have 5 digitations, or alternatively expressed, 4 short digitations below the larger curved digitation. VoKEs (op. cit.) contends that M. uncinarius has only + varical digitations, whereas M. mitriformis Sowerby, 184i (non Wood, 1828) has 5. BarNarp (1959) describes M. uncinarius as pure white, with beach specimens buff, pink or brown, and with 2 to 4 and occasionally 5 smaller pro- cesses below the uppermost expansion. 9. The species Murex noduliferus Sowerby, 1841, was placed by me in the genus Pozrieria Jousseaume, and in the discussion the genera Murexsul Iredale and Muri- copsis Bucquoy, Dautzenberg & Dollfus were also con- sidered. VoxEs (op. cit.) indicated a placement of the species in the genus Muricopsis because of the apertural denticulations. In some specimens of M. noduliferus the columella is completely smooth, while in others there may be up to 4 small denticles on the anterior part of the columella. Murex blainvillei Payraudeau, 1826, the type species of Muricopsis, lacks the produced and open spines, the slender and elongated siphonal canal and the promi- nent, concave and circular columellar shield which joins the outer lip without interruption; the operculum of Mu- vex noduliferus is thin, light brown in colour and has an apical nucleus. Specimens of Murex noduliferus in the U. S. National Museum have been labelled Potrieria (Murex- sul) nodulifera by either Dall or a subsequent curator, and a similar species, Murex (Poirieria) depontaillieri Coss- mann, 1903 from the European Pliocene, has also been placed in Poirieria by the describer in 1903. Now that I had the opportunity to examine large series of Murex octogonus Quoy & Gaimard, the type species of Murexsul Iredale, I reconsider my original assignment and place Murex noduliferus in the genus Murexsul, pending an examination of the radula. The prominent columellar shield, short open spines, elongated canal and number of varices are characters common to both species. Murex noduliferus, however, has 5 to 7 denticles on the outer lip, whereas M. octogonus has more numerous and close- set crenations on the outer lip which extend as short plicae into the aperture. Differences in columellar denticulation will also be found in the species Pterynotus (Naquetia) tri- pterus (Born) and P (N.) triqueter (Born), where one is prominently denticulate, the other is smooth. 10. Examination of several muricid species in the British Museum (Natural History), London, convinced me about the futility of “off the cuff” statements on the subject of relationship and identity of Favartia species. A detailed study, combining geographical distribution, ecophenotypic variation, taxonomic priorities and the soft parts, is ur- gently needed before emphatic statements on and elucida- tion of species of the Favartia complex can be made. 11. Murex secundus Lamarck, 1822: two syntypes of this species are in the Muséum d’Histoire Naturelle, Gene- va, nos. 1099/43 /1-2. The larger specimen, no. 1099/43/1, length 44.4 mm, is the specimen for which Lamarck gave dimensions (21 lignes == 47.2 mm), and which has been figured by KienErR (1842, plt. 8, fig. 2). This specimen, which is here selected as the lectotype of Murex secundus Lamarck (Figure 9), is a worn shell, white in colour with blackish-brown digitations, a smooth columella and 13 denticles on the outer lip; the second syntype is smaller than the lectotype, and according to R. de Lamarck only 2 specimens were present in her father’s collection. The species has been reported from Northern Australia in malacological literature under the name Murex vari- cosus Sowerby, 1841. Sowerby’s species, described from unknown locality, but subsequently reported from the Red Sea, is a form or subspecies of Homalocantha secunda (Lamarck). ACKNOWLEDGMENTS The writer would like to thank Dr. E. Binder, Muséum d’Histoire Naturelle, Geneva, and Dr. N. Tebble, formerly of the British Museum (Natural History), London, for having made the type collections available for examina- tion; their assistance and suggestions have been greatly appreciated. Literature Cited BARNARD, KeprpeL Harcourt ; 1959. Contributions to the knowledge of South African marine Mollusca, Part II :Gastropoda: Prosobranchiata: Rhachiglossa. Ann. South Afric. Mus. 45 (1): 1-237; 52 figs. (June) Vol. 14; No. 2 EMV ERIGER Page 191 CrERNOHORSKY, WALTER OLIVER 1967. The Muricidae of Fiji (Mollusca : Gastropoda) Part I Subfamilies Muricinae and Tritonaliinae. The Veliger 10 (2) : 111 - 132; plts. 14, 15; 11 text figs.; 1 map (1 October 1967) 1969. The types of the Lamarck collection in the Muséum d’ Histoire Naturelle in Geneva. Recent Mollusca of the genera Mitra, Columbella (part) and Cancellaria (part). Rev. Suisse de Zool. 76 (4) : 953 - 994; plts. 1-7 (December ’69) Cossmann, ALEXANDRE Epouarp Maurice 1903. | Essais de paléoconchyliologie comparée, vol. 5 (Paris) (chez l’auteur): 215 pp.; 9 plts.; 16 text figs. Couturirr, M. 1907. Etude sur les mollusques gastropodes recueillis par M. L.-G. Seurat dans les archipels de Tahiti, Paumotu et Gambier. Journ. de Conchyl. 55 (2) : 123 - 178; plt. 2 (25 Aug. ’07) Doncr, HENRY 1957. A historical review of the mollusks of Linnaeus. Part 5. The genus Murex of the class Gastropoda. _—_ Bull. Amer. Mus. Nat. Hist. 113 (2): 77 - 224 (30 September 1957) DUNKER, GUILIELMO 1882. Index molluscorum maris Japonici conscriptus et tabulis iconum XVI illustratus. 1-16 HANLEy, SYLVANUS 1855. Ipsa Linnaei Conchylia; the shells of Linnaeus, deter- mined from his manuscripts and collections. London, 556 pp.; 6 plts. Kiener, Louis CHARLES 1842-1843. Spécies général et iconographie des coquilles vivantes; genre Rocher. Paris 7: 1 - 130; plts. 1-47 [plates issued 1842; text issued 1843] Lamarck, JEAN-BaptisTE PIERRE ANTOINE DE MONET DE 1822. Histoire naturelle des animaux sans vertébres, 7 [Mol- Cassel (T. Fischer), pp. 1 - 301; plts. lusques]. Paris (“chez l’auteur, au jardin du Roi”) pp. 1-711 (August 1822) LINNAEus, CAROLUS 1764. | Museum s:ae r:ae m:tis Ludovicae Ulricae Reginae Svecorum. L. Salvii, Holmiae, pt. 2: 1-722 MartTINI, FriepricH HetnricH WILHELM 1777. | Neues systematisches Conchylien-Cabinet. Nirnberg, 3: 1-434; plts. 66 - 121 Montrort, PirrrRE DENYS DE 1810. \ Conchyliologie systématique, et classification méthodique des coquilles; ... 2 [Coquilles univalves, non cloisonnées] Paris (FE Schoell), pp. 1-676 + 1 - 16; illustd. Reeve, Lovett AuGUSTUS 1845. Conchologia Iconica. London, 3, Murex: plts. 1 - 36; 1 suppl. plt. (April 1845 - April 1846) ReEHDER, HarAtp ALFRED 1967. Valid zoological names in the Portland catalogue. Proc. U. S. Nat. Mus. 121 (3579): 1-51 Rippincace, O. H. « D. EF McMicHarEt 1961. Queensland and Great Barrier Reef shells. (Jacaranda Press), pp. 1 - 210; plts. 1 - 29 TomLin, JouN Reap LE Brockton « Ronatp WINCKWORTH 1936. An index to the species of Mollusca in the Beschreibung of H. F Linx. Proc Malacol. Soc. London 22 (1). 27 - 48 (14 March 1936) Brisbane VoxEs, Emity Hoskins 1964. | Supraspecific groups in the subfamilies Muricinae and Tritonaliinae (Gastropoda: Muricidae). Malacologia 2 (1): 1-41; plts. 1- 3 (103 figs.) (September 1964) 1970. | Some comments on Cernohorsky’s “Muricidae of Fiji” (The Veliger, 1967). The Veliger 13 (2): 182 - 187 (1 October 1970) Page 192 THE VELIGER Vol. 14; No. 2 Effect of Scorpion Venom on the Ciliary Activity of Fresh Water Mussel D. CHENGAL RAJU, R. V. KRISHNAMOORTHY anv A. SUBBARAMI REDDI Department of Zoology, Sri Venkateswara University, Tirupati, A. P, India (2 Text figures) ALTHOUGH NUMEROUS investigations have been conduc- ted on the chemical make-up of the venoms of several scorpions, comparatively scanty information is available on the biochemical and physiological effects of these ven- oms. Preliminary studies of OoMMEN et al. (1964) have shown that the venom of the South Indian scorpion, Heterometrus scaber, inhibits strongly the activity of lac- tate, citrate and succinate dehydrogenases of frog muscle. Similar results were obtained on the dehydrogenases of cockroach muscle (Basu et al., 1971). In the present in- vestigation an attempt was made to study the effects of the venom of another South Indian scorpion, Heterometrus fulvipes, on the ciliary activity of fresh water mussel, since the ctenidia of this bivalve are known to be involved in the respiration and feeding of the animal. The venom of this species of scorpion is of special interest because of its deleterious effects on several invertebrates and verte- brates, including human beings. The choice of this mate- rial was made because of direct visual observation of the effects of the venom on the ciliary activity. MATERIAL anp METHODS The scorpions, Heterometrus fulvipes, were collected from the surrounding places of the University Campus. The venom was extracted by electrical excitation as follows: one electrode was placed in contact at the telson joint and the other at the arthrodial membrane of the chelate leg. Make and break stimuli were applied with a dry battery of 1.5 volt in circuit. Venom collected as a result of this electric excitation at the tip of the sting was removed with a pipette. A complete ctenidium of the fresh water mussel, Lamel- lidens marginalis, was isolated and fixed on a wax-laden finger bowl. This preparation was kept in pond water. Ciliary activity was observed by the movement of a fine film strip bit placed at the edge of the gill as recommended by WetsH & SmitH (1960). The time taken for the film strip to be dragged of 1 cm of the length of the gill was noted. The reciprocal of time was taken as the measure of the ciliary rate. The experiment was repeated with the natural medium at temperatures of 35°, 30° and 25° C. Temperature was maintained by keeping the finger bowl in a water bath with the desired temperature. The same film strip was used for all the experiments. The data were subjected to statistical validation. The medium with venom added was prepared at a concentration of 0.01 ml venom per 10 ml pond water. Per cent changes in the ciliary rate in the medium with venom and the venom-free medium were calculated over that in the normal medium, considering the latter as 100%. Logarithmic dilutions were made with pond water. For the recovery experiments, venom-free medium was prepared by replacing the pond water with venom added with natural pond water after washing the preparation thoroughly with pond water. The magnitude of the effect of the venom at different temperatures was evaluated through Q,) (PROSSER & Brown, 1961). RESULTS anv DISCUSSION It is clear from Table 1 that the venom of the scorpion in general inhibited the rate of ciliary activity. After the addition of the venom the activity decreased by about 21% and when all the venom was removed by replacing it with fresh pond water the restoration of activity to normalcy falls short by only 9% (Table 1). This experi- ment shows that evidently the venom causes reversible inhibition as long as it is present in the medium and when it is removed, the original activity is restored. Figure 1 illustrates the rate of ciliary beat effected by the dilution Vol. 14: No. 2 THE VELIGER Table 1 Changes in the ciliary rate of fresh water mussel in media with venom added (0.01 ml/10 ml) and in venom-free media 38 8 & % ciliary rate after E & 10min. at 30° C Environment 2B over normal Zo Normal (pond water) 12 100.00 Venom added (inhibition experiment) 12 79.00 + 4.48 Venom-free after thorough washing 12 91.00 + 2.30 the preparation with pond water (recovery experiment) % Inhibition G3 102 105 10 107 OG log Dilution Figure 1 of the venom. As is evident from the figure the greater the dilution the less was the inhibition and finally the dilution over 10° would not inhibit the ciliary activity to any detectable degree. The rate of movement of cilia on the addition of venom in relation to temperature is given in Figure 2. At all temperatures the general trend of the ciliary activity in the medium with venom added remained the same, but the magnitude of activity varied with the temperature. The rate of activity decreased with increasing temperature, indicating that the venom is more active at higher tem- peratures. It appears probable that increase of tempera- ture facilitates the faster diffusion of the venom into the cytoplasm resulting in the decreased activity of cilia. Page 193 $6 25° C 33333 30° C 35°C % Ciliary Activity after Venom Addition ! ! 2 & & 8 10 1 Te iG me yu. 22 Time in minutes Figure 2 Hence it is suggested that the inhibition of ciliary beat by the venom is temperature dependent. In order to know the magnitude of the effect of temperature on ciliary rate in medium with venom added, Q,, values were calculated for the temperature ranges at which the ciliary activity was studied. It is evident from Table 2 that the Q,) values for both higher and lower ranges of temperature are not similar and are statistically insignificant. As Q,. is the measure of the rate of reaction (PRossER & Brown, 1961) and as it is the same in the higher and lower ranges of temperature studies, the rate of ciliary function changes in the same magnitude over the normal on both extremes of temperature range studied in the medium with venom added. Table 2 Q,, values of the rate of ciliary activity in medium with venom added (0.01 ml/10 ml) Change tay ©) values at higher Temperature range t test ranges of tem- 25 - 30° C 30- 35°C (a=) perature 1.17 £0.1307 1.29+0.118 t = 0.2894 _ Insignificant since P > 0.05 There was an outburst of ciliary activity immediately after the introduction of the medium with the venom added (Figure 2). This overshoot response then gradually Page 194 THE VELIGER Vol. 14; No. 2 diminished and the real inhibition due to the presence of the venom in the environment was established at every temperature. It is clear from the diagram (Figure 2) that the outburst of activity was more at 25° C and less at 35° C. The overshoot response observed here may be com- pared with that described by GratnceR (1958), accor- ding to whom this response is the result of a feed back control to the immediate change in the natural habitat with the addition of toxins. In order to resist this toxicity, the system accelerates its activity but apparently fails to maintain it due to the over-impeding forces of toxicity, which finally cause inhibition. The inhibition of ciliary activity in the presence of venom may be explained on the permeability properties of the cell membranes also. It is known that toxins alter the permeability of the cell membranes besides other ef fects on physiological processes (ABBOTT & BALLANTINE, 1957; BERGMANN et al., 1963; Parnas, 1963). Hence it is suggested that the scorpion venom may contain several toxic substances which affect the permeability of the cili- ary membranes, resulting in the decreased activity of the cilia. Since the main function of ctenidia in the fresh water mussel is respiration, it appears quite likely that the scor- pion venom inhibits the respiratory metabolism of the animal also. Further studies along these lines are worth attempting. Another interesting feature observed during this in- vestigation was the excessive secretion of mucus over the gill fragments when the venomous medium was added. But the cause for this is unknown. SUMMARY 1. The rate of ciliary activity of fresh water mussel was studied at different temperatures in the environment of scorpion venom. The activity was found to be inhibited by the venom; the degree of inhibition was found to be dependent on the dilution factor. 2. The onset of inhibition was dependent on time and temperature. 3. An overshoot response was observed immediately after exposing the cilia to the environment with venom ad- ded. The possibility of scorpion venom altering perme- ability of the ciliary membranes was discussed. ACKNOWLEDGMENTS The authors wish to thank Dr. Karumuri S. Swami, Head of the Department of Zoology, for his helpful comments and suggestions. Literature Cited Assort, B. C. « D. BALLANTINE 1957. The toxin from Gymnodium veneficum Ballantine. Journ. Mar. Biol. Assoc. U. K. 36: 169 - 189 Basu, K.S., P M.K. Dass « S.A. T. VENKATACHARI 1971. Effects of scorpion venom on some physiological pro- cesses in cockroach. Toxicon 9: 119 - 124 BrercMANn, EF, I. Parnas & K. ReEIcH 1963. | Observations on the mechanism of action and on the quantitative assay of ichthyotoxin from Prymnesitum parvum Carter. Toxicol. Appl. Pharmacology 5: 637 - 649 GrainceEr, J. N. R. 1958. In: Physiological Adaptation. C. L. Prosser, ed. pp. 79 - 90. Amer. Physiol. Soc. Washington, D. C. Oommen, P. K. « R.A. Kurup 1964. Protein and amino acid contents and physiological prop- erties of the venom of the South Indian scorpion, Heteromet- rus scaber. Indian Journ. exp. Biol. 2: 78 - 80 Parnas, ITzcHaK 1963. ‘Toxicity of Prymnesitum parvum (a review). Israel Journ. Zool. 12: 15 - 23 Prosser, C. L. « E A. Brown 1961. | Comparative animal physiology. Philadelphia; 239 pp. WetsH, J. H. « Ratpu I. SmirH 1960. Laboratory exercises in invertebrate physiology. Burgess Publ. Co., Minneapolis, Minn. 80 pp. W. B. Saunders Co., Vol. 14; No. 2 THE VELIGER Page 195 The Effect of Storms as a Density Dependent Mortality Factor on Populations of Sea Mussels J. R. E. HARGER' D. E. LANDENBERGER * Department of Biological Sciences, University of California at Santa Barbara, California 93106 (6 Text figures) INTRODUCTION WE HAVE STUDIED competitive interactions between the two species of sea mussels, Mytilus edulis Linnaeus, 1758, and M. californianus Conrad, 1837 (Harcer, 1967) and predation on mussel populations by 2 species of seastars, Pisaster ochraceus Brandt, 1835, and P. giganteus Stimp- son, 1857 (LANDENBERGER, 1967). In these studies we found that the loss of mussels from beds through storm action was related to the size of the bed. This loss was dis- proportionate, in that large beds lost relatively more mussels than did small ones. We found further that mussel beds of a given size which had been heavily attacked by seastars prior to severe storms were also the more adversely affected by the storms. The purposes of this paper are to present the evidence for these statements and to comment briefly on their relevance to current ideas about the “regulation” of num- bers in populations. PREVIOUS REPORTS on THE EFFECT oF STORMS on MUSSELS We have found only 2 references to this phenomenon. Wuite (1937) reports that at St. Anne’s-on-the-Sea, My- tilus edulis settle on gravel, grow for a few years, accumu- lating silt and excreta within the bed, until finally “heavy seas reaching the bed roll up the whole mass of mud and mussels like a carpet and break it to pieces on the fore- 1 Present address: Department of Zoology, University of British Columbia, Vancouver 8, British Columbia, Canada. 2 Present address: Department of Zoology, University of Cali- fornia, Los Angeles, California 90024 shore.” This growth and destruction is repeated again and again. Feper (1956) reports that large masses of mussels (M. californianus) are lost from the intertidal beds at Monterey Bay during the winter storms. Also, J. H. Connell (personal communication) has photographs from the coast of Scotland which show heavy mortality in beds of M. edulis as a result of storms. The mortality was highest in dense beds, where many mussels were attached to other mussels rather than to the rock substrate. Tue HABITAT oF tHE MUSSELS The work reported here was done at Ellwood Pier, about 14 miles west of Santa Barbara, California. This pier extends about 4 mile offshore from a sandy beach in an area of protected outer coast. The pilings (about 400) which support the pier are steel I - beams; mussel clumps grow intertidally on the pilings (for a detailed descrip- tion of these populations see Harcer, 1968). We regard each mussel clump on its piling as a distinct population. These populations of mussels range in size from a few individuals to masses over 17 feet (5.2m) in circumfer- ence. The other abundant organisms are two species of asteriid seastars, Pisaster ochraceus and P. giganteus. These are the major predators on the large mussels. During most of the period of study (early 1965 to early 1967) the weather was calm, except for severe storms in December 1965 and January 1966. METHODS We recorded to the nearest foot the maximum circum- ferences of 350 mussel beds in May 1965, October 1966, Page 196 THE VELIGER Vol. 14; No. 2 and May 1967. At first we used a tape measure to deter- mine clump circumference, but later found that our estimates of these values were quite accurate. To check estimates at each census, we measured the circumfer- ences of mussel beds on 41 pilings in different locations throughout the length of the pier. All estimates of these clumps were within one foot of the measurement; most were identical. dry tissue weight (ke) aD 0 200 400 600 800 1000 1200 1400 1600 1800 (circumference : feet)3 Figure 1 Relationship between clump circumference (cubed) and biomass (dry weight of tissue in kilograms) The regression equation is: Y = —0.3749 + 0.00754x To estimate the biomass of mussel clumps, we measured and then dissected sections of several mussel beds of vari- ous sizes. Using size frequency distributions of mussels present in the sections of each clump, together with a regression of dry body weight (not including the shell) on length (distance between the anterior hinge and pos- terior siphon region of mussel), we computed the total dry weight (biomass) present in clumps of a given cir- cumference. The relationship between total dry weight and the cube of the clump circumference is linear (Figure 1). A clump of medium size (one of about 12 feet cir- cumference - 3.7m - in May 1965) contained over 11000 individual mussels whose total dry body weight was 7.58kg. The estimates of predation referred to below are aver- ages of several counts of the numbers of seastars (greater than 3 inches - 7.6cm- in radius) observed on or just below each mussel bed. The feeding rates of the 2 species of seastar are different (LANDENBERGER, 1967), and a slight preference for Mytilus edulis over M. californianus has also been observed for both seastars (LANDENBERGER, 1968). Neither of these factors was specifically considered ; intensity of predation on each mussel bed was taken as proportional to the number of seastars present. LOSS or MUSSELS purine 1965 - 1966 The second measurement of the mussel populations in October 1966 was about 9 months after storms (December 1965 - January 1966). During that period, some growth (or less likely, additional loss) must have occurred. Thus, our 1966 records probably overestimate the sizes of the mussel beds immediately after the storms. Likewise, our first estimates would, in general, underestimate the sizes of the populations immediately before the storms. Never- theless, these sources of error do not make a consistent bias in estimating the effect of winter storms. 8 + e Ww oad e e & e pao 6° e e@ e e CY) e 2 e & —5- e e e e e e o “ 4; @| 301 32 ay Holt aromas 3 9 -3; ee ‘e e e a) ¢ =—2 * O e %e e 0 e $e @ e % =ll4 or ek le e e he eo e e S g 0; 8 I PO FRR 399313595 S) +1; one) ie ee +21 . db & ON a aac 8 10° “io. ea original clump circumference (feet) Figure 2 Relationship between original clump circumference and change due to the storms of December 1965 to January 1966. All measure- ments in this sample were by estimation. First measurement May, 1965; second, October, 1966. Figure 2 shows the change in circumference of each mussel bed as related to its original (pre-storm) circum- ference. This significant relationship is approximately lin- ear but because of the cubic relationship between circum- ference and biomass, the loss in biomass was dispropor- tionate for larger beds. The information of Figure 2 has Vol. 14; No. 2 been compressed and presented in Figure 3 where the populations have been grouped according to original size; the average biomass lost for each of these is shown as a percentage of the original biomass. This relationship sug- gests a density-dependent effect of the storms: the larger 100 90° 80 on D> ~ Ss Oo i=) (=) e % loss of biomass due to storms oO oO 20° 10; 0 10 ; 90 , 30 original biomass (ke) Figure 3 Relationship between original clump biomass and change due to the storms of December 1965 to January 1966. The information contained in Figure 2 has been compressed and presented here. The mean amount of material lost for each group of clumps of the same size is plotted as a percentage of the original clump mass. the bed of mussels, the heavier its losses. It is to be noted (Figure 2) that there was no apparent effect on popula- tions less than 7 feet in circumference; these grew. We also compared losses from mussel clumps which had been heavily attacked by seastars (3 or more seastars per THE VELIGER Page 197 —8° -—6° 25 Bor change in circumference (feet) dq 8 10 12 14 16 original clump circumference (feet) Figure 4 Comparison between the losses suffered by clumps rated as ex- periencing heavy predation (C)) and those suffering light predation () during the period from May 1965 to October 1966. The regression lines are not significantly different in slope but are sig- nificantly different in position at the point of mean clump size (12.04 feet). High predation is defined as more than 3 sea stars per clump. census, usually 7 to 10) before the storm to those clumps which were not heavily attacked, 7.¢., having fewer than 3 seastars (average of 2 censuses during summer and autumn 1965). Clumps with fewer seastars suffered significantly lighter losses than did those which had more seastars feeding on them (Figure 4). The density-dependent effect seems to be a consequence of the way the mussel beds grow. In small beds of mussels, all individuals are bound tightly together. Most of the mussels are attached directly to the substrate (in this case, the pier piling). In large or thick beds of mussels, rela- tively fewer of the individual mussels are attached directly to the piling, so the unit as a whole is much less stable. Page 198 THE VELIGER Vol. 14; No. 2 Since the volume of a clump, and thus the number of mussels, varies approximately as the cube of the circum- ference, this instability increases rapidly with growth in large clumps. Very large clumps can be easily moved back and forth by hand, whereas smaller clumps are quite firmly attached to the pilings and mussels can only be removed by means of the expenditure of considerable effort. Predation makes a bed of any size still less stable because the seastars feed mainly at the base near the center of the clump of mussels, next to the piling. They remove those mussels which are attached either to the piling or to the mussels next to the piling. These are the mussels which bear most of the weight of the clump. A heavily attacked mussel bed is extremely weak in several places; even heavy swells may cause sections of a weak- ened clump to fall away. Thus, predation by seastars tends to decrease the stability of a bed of any size, so that the effect of a storm of any intensity will be increased. CHANGES 1n MUSSEL POPULATIONS puRING CALM WEATHER Figure 5 is a similar plot of change in the circumference of mussel beds between October 1966 and May 1967. This shows no consistent relationship between size of population 6° —5)q => A; C) e e o & Se e Bune . 5 _5yd ‘ss e ee < @ @ @ e e ® 5 = e ® e e 8 ® e £ 5 e 3 3 @ e 5) e@ e SOR eg a aT EE OG Ce EL a 2 Sie Leet tei, Nia ga Oa ares oll eS anata’ wre \wk@e Ss @ e 3 C mn} ms tL 9c e e © e s e e e e e +3. e e e 4 Si eA ie | We original clum circumference (feet) Figure 5 Relationship between original clump circumference and change between October 1966 and May 1967. All measurements in this sample are by estimation. and mass lost or gained. Much of the variability could be traced to differences in intensity of predation by seastars; unfortunately, we have only one census at the beginning of this period. However, previous censuses show (LAN- DENBERGER, in MS) that intensity of predation is very patchy, in that beds in certain sections of the pier are heavily attacked for long periods of time, while beds in other sections are largely free of seastars. The cause of this local patchiness is not well understood at present, nor is it known how rapidly, how often, or over what area of the pier these patterns change. Another factor which helps impose variability on the overall picture arises from the fact that the effect a storm has on a population consisting of both Mytilus edulis and M. cali- fornianus depends on both the proportional representation of the 2 species and the size of the constituent individuals. Clumps are progressively weakened by an increasing con- centration of M. edulis (Harcrr, 1970). These are just 2 of a number of possible influences which are ignored in diagrams such as Figures 2 and 5. Another is the different degrees of exposure to wave action experienced by mussel beds on pilings in different depths of water. Beds growing on pilings in shallow water (where wave action is more intense but predation less so) lost more during the storms than did beds on pilings in deep water (Figure 6). Other sources of mortality for which we have | iM &&E&SGS change in circumference (feet) 4 6 8 10 12 14 16 original clump circumference (feet) Figure 6 Relationship between original clump circumference and change due to the storms of December 1965. All measurements in this sample were made directly with a tape measure. Surf zone pilings are represented by crosses. First measurement, May, 1965; second, October, 1966. Vol. 14; No. 2 THE VELIGER Page 199 evidence (Harcer, 1967) are: (1) crowding and crush- ing of Mytilus edulis by M. californianus within the mus- sel beds; (2) predation by crabs (mainly Pachygrapsus crassipes and Cancer antennarius) on young mussels in newly colonized areas. All of these interactions may be modified by effects of weather. VARIATION in THE NUMBER or MUSSELS AT ELLWOOD PIER We think that the weather may play a major role in limiting the numbers of mussels in populations at Ellwood Pier. Of course, our understanding of this situation is incomplete. Yet, knowing that weather can have a densi- ty-dependent effect, we can construct the following hypo- thetical picture which may be realistic. We suppose that storms cause disproportionately great mortality in large populations but little or none in small ones. Predation by seastars increases the vulnerability of any mussel popula- tion to wave action, such as those populations also suf fer increased mortality during severe weather. During a long period of calm weather, some mussel beds would grow to great size. But the larger these populations grow, the more likely they are to suffer from even moderately heavy wave action. Conversely, many successive intense storms would not in themselves cause all the beds of mussels at the pier to become extinct, because after the first few storms only small populations would be left and these would be able to grow even when storms were frequent. These considerations hold even in the absence of predation, because the effect of storms is density-de- pendent regardless of predation. It is of no consequence to the argument that storms are unpredictable in their time of occurrence or their intensity. Our simplified scheme requires only that they do happen from time to time. Such has been the case previously; it is probable that the 3-to-5 year interval (more or less) between very heavy winter storms will continue. To predict the size of mussel beds at some future time, one would need to know the size and constitution of the mussel population (in terms of size of individual mussels) after the last storm, and the length of time favorable for growth and recruitment of mussels since that storm. To predict the effect of a future storm, we need to know its intensity, the distribution of the sizes of the mussel popu- lations, their constitution, and the extent to which each has been attacked by seastars before the storm. All the quantitative relationships among these variables have yet to be determined. Other factors, such as patchiness of predation in different sections of the pier, and patchiness of recruitment of mussels from year to year, impose variability on this general picture. The question concerning the definition of the constitu- tion of a population has relevance when we attempt to generalize arguments based on processes observed to act on mussel clumps at Ellwood Pier. It might, for instance, be argued that all the mussels in the Santa Barbara region form a population and the effect of storms on the pier mussel clumps is only a minor detail in the overall popula- tion processes. In a species which has as part of its life history a planktonic phase, as do sea mussels, the possibil- ity of concocting a definition of “population” by recourse to a localized “genetic pool” description seems somewhat remote. Consequently, we are left with a “spatial” defi- nition - a population of mussels is any spatially isolated, clearly defined group whose members are, or tend to be, exposed to similar factors affecting growth and survival. A group of mussels may extend unbroken for several miles along a shoreline, in which case functional units to be identified as “populations” would be sections exposed to similar conditions as defined above. In other situations, populations, each with differing histories, may be aggre- gated spatially (7. e., the mussel clumps on the pier). Such aggregations may conceivably have no effect on popula- tions outside their vicinity and, therefore, themselves merit recognition as a group (whose members may affect each other). The presence or absence of mussels on EIl- wood Pier is unlikely to affect mussels on the breakwater around the Santa Barbara harbor, except in the case that significant numbers of recruits are supplied to the latter populations by the former. Populations, as defined above, are the smallest functional units, within the range of the species, where the welfare of the individual directly affects the welfare of the group to which it belongs. We have evidence that processes, as outlined, affecting the clumps at Ellwood Pier, work in similar ways on the ad- jacent shore populations. RELEVANCE or tuis STUDY TO THE QUESTION or REGULATION The term ‘regulation’ is used by engineers to describe the process by which a system acts in order to keep it at or near some predetermined point. When this term is applied to populations of organisms such a point (equi- librium density) seems implicitly assumed, in some sense, to be the “carrying capacity” of the environment (ERRING- Ton, 1946). For instance, NicHotson (1954) regards density-dependent processes as acting in a compensatory way against any departure from a fluctuating “equilib- Page 200 THE VELIGER Vol. 14; No. 2 rium density;” these processes, then, act to regulate the population about the equilibrium density. In fact, SoLo- mon (1964) formulates regulation as the result of the action of density dependent processes. Similarly, ErsENBERG (1966) defines regulation as “The maintenance of the numbers of animals in a natural population within a certain range, around some level that is determined by the whole of the environment, and which is brought about as a result of feedback from popu- lation density.” Defined in this manner, regulation can only be density-dependent. NIcHOLSON (of. cit.) phrases the problem as follows: “Although true equilibrium is impossible under fluctuating conditions, there is at each moment a density level which, if it were attained by the popu- lation, and if the environmental conditions prevail- ing at that moment were to persist, would cause the environmental forces opposing density change, in- cluding those induced by the populations, to exactly counterbalance the properties of the population fa- vouring multiplication. Consequently, it can be said that the level of equilibrium density fluctuates in association with environmental fluctuations, through the effects these have upon the properties of animals and those of their requisites. Reactions tending to cause increase or decrease are produced respectively when a population is below or above the equilibrium density appropriate to the conditions prevailing at each moment. Consequently, reaction holds popula- tions in leash to the ever-changing levels of their equilibrium densities. Although such influences as developmental lag, and the coupling of prey popula- tions with those of their predators, may cause oscil- lations of internal origin, reaction forces such oscilla- tions to take place about the equilibrium levels which change with the changing environment.” Difficulties arise when we attempt to define this equi- librium level since it can only be done in terms of the past history of the population and the environment; that is, it can only be defined in retrospect. Not only that, but since as Nicholson says “true equilibrium is impossible under fluctuating conditions,” and, since conditions always fluctuate, then the only populations not responding under the influence of regulatory processes, such that they will be preserved, will be those immediately bound for extinc- tion. In other words, all populations are either responding under the influence of “regulating” factors such that they will survive, and thus be described as “regulated” or they are not so responding, and so will become extinct. We think most ecologists would agree that the effect of weather can be density-dependent (7. e., by influencing a greater proportion of animals at higher densities than at low densities). However, even in the most recent liter- ature on “regulation” of populations one finds broad state- ments such as the following: “The regulation of the densi- ty of animal populations by density-independent weather factors as such is clearly an impossibility” (Ktomp, 1962; we assume that Klomp means that “weather factors” are by definition density-independent). Or further, “It is generally agreed that influents such as weather, not re- sponsive to population density, commonly have a density- independent action in a population It has been argued that the effects of influents that are apparently density-independent may in fact often depend in some small degree on population density’ (ANDREWARTHA & Bircu, 1954; Cuirry, 1960). However that may be, SoLtomon (1964) states “If their action cannot be shown to be substantially dependent on density, it is realistic to treat them as density-independent.” The difficulty with claims such as these lies in their implicit concern with “factors” rather than effects. The density-dependent effect which we claim for the weather seems quite consistent with the considerations of ANDRE- WARTHA & BircH (1954) that a small number of animals may be better protected than a larger number in the same area because all places in an animal’s environment do not provide equal protection from the elements. The environ- ment of animals includes other animals of the same kind; in unfavorable weather the probability of death of a mus- sel in a bed depends on how many other mussels are in that bed. We agree with Andrewartha « Birch that all “factors” can have density-dependent effects; hence, the term is practically meaningless when applied to factors per sé. Implicit in the idea of regulation (so it seems to us) is that a population which is “regulated” has a lower probability of extinction than one which is not. Thus, it may also be incorrect to equate regulation with density- dependent effects, for such effects may increase the prob- ability of extinction. At this point we note the distinction between responsive and unresponsive factors made by NicHoLson (op. cit.). He conceived responsive factors as being instigated (pro- gressively) by the growth of the population on which they act. Unresponsive factors, on the other hand, occur independently of and remain uninfluenced by any change in the population concerned. Responsive factors impose density-dependent effects which vary progressively as the population density changes in time and are therefore un- likely to increase the probability of extinction. The storms (an unresponsive factor), however, act at one instant in time and so their density-dependent effect could be de- vastating. Such is the case in mussel beds, where a very large population of mussels is likely to become extinct, or Vol. 14; No. 2 THE VELIGER Page 201 nearly extinct, in the next storm. Thus, because of a Curry, Dennis density-dependent effect, mussel populations seem not 1960. Population processes in the vole and their relevance to to be regulated according to that criterion. (Density-de- pendent effects of responsive factors could, however, be thought of as contributing to decreasing the probability of extinction of a population. ) It seems permissible to say that the total number of mussels at Ellwood Pier is “regulated” in the sense that the probability is low that all populations will become ex- tinct at once. But this is not a consequence of density-de- pendence; rather, it is because there are so many mussel populations, each with different characteristics and re- sponses to environmental changes. Moreover, we assert that the amount of variation in the overall numbers of mussels from year to year, whether great or small, has little or no bearing on the question of extinction. We can, however, make an effort to understand the changes in local populations. These may have many causes and may also be extreme; in any case, both the amount of variation and its causes will be different in different mussel clumps, depending on their size, extent of predation, the weather, past history of recruitments, etc. To what degree each of these populations is “regulated” is really just a matter of terminology and definition. For the reasons given then, we reject the concept of regulation as useless. At best, it contributes nothing to our understanding. At worst, it is a red herring. All we can say is that the presence of a viable population indicates that it has in the past been regulated in as much as it is not now extinct. ACKNOWLEDGMENT These ideas arose out of consideration of the results of field work undertaken by the authors under the guidance of Dr. J. H. Connell. Literature Cited ANDREWARTHA, HERBERT GEORGE & L. CHARLES BircH 1954. The distribution and abundance of animals. Univ. Chicago Press, Chicago. xvi-+ 782 pp. general theory. EIsENBERG, R. M. 1966. The regulation of density in a natural population of the pond snail Lymnaea eleodes. Ecol. 47: 889 - 906 Canad. Journ. Zool. 38: 99 - 113 ErRINGTON, PAu L. 1946. Predation and vertebrate populations. Biol. 21: 145 - 177; 221 - 245 Freper, Howarp MitcHELL Quart. Rev. 1956. Natural history studies on the starfish Pisaster ochraceus (Brandt, 1835) in the Monterey Bay area. Ph. D. dissert., Stanford University, Stanford, Calif. Harcer, JoHN Rosin E. 1967. Population studies on Mytilus communities. Phy Ds Dissert., Univ. Calif. Santa Barbara; Univ. Microfilms No. 69-1719 1968. The role of behavioral traits in influencing the distribu- tion of two species of sea mussel, Mytilus edulis and Mytilus The Veliger 11 (1): 45-49; 3 text figs. (1 July 1968) 1970. The effect of species composition on the survival of mixed populations of the sea mussels Mytilus californianus and Mytilus edulis. The Veliger 13 (2): 147-152; 5 text californianus. figs. (1 October 1970) Komp, H. 1962. The influence of climate and weather on the mean density level, the fluctuations and the regulation of animal populations. Arch. néerl. Zool. 15: 68 - 109 LANDENBERGER, DONALD E. 1967. | Studies on predation and predatory behavior in Paci- fic starfish (Pisaster). Ph. D. dissertation, Univ. Calif. at Santa Barbara 1968. Studies on selective feeding in the Pacific starfish Pis- aster in Southern California. Ecology 49: 1062 - 1075 Nicuotson, A. J. 1954. An outline of the dynamics of animal populations. Austral. Journ. Zool. 2: 9-65 Sotomon, M. E. 1964. Analysis of processes involved in the natural control of insects. In: Advances in ecological research, J. B. Cragg (ed.) Academic Press, New York and London, vol. 1: 1-58 WuitrE, KATHLEEN M. 1937. Mytilus. typical British marine plants and animals 31: 1 - 77 Liverpool marine biol. committ. Mem. on Page 202 THE VELIGER Vol. 14; No. 2 Cell Renewal Systems in the Gut of the Oyster, Crassostrea gigas”? (Mollusca : Bivalvia ) MICHAEL C. MIX Department of General Science; Oregon State University; Corvallis, Oregon 97331 (2 Plates) THERE HAS RECENTLY BEEN much interest in the field of oyster histopathology in relation to disease, experimental wound repair, inflammation, and effects of various insults on certain tissues. However, except for the origin of oyster blood cells, which has interested biologists for many years, there have been virtually no studies or reports con- cerned with basic cell renewal systems of any oyster tissue. There are a few scattered reports of mitotic figures observed in the digestive tissues of Crassostrea virginica (Gmelin, 1791) (Yonce, 1926; SHaw «& Bartte, 1957; Hittman, 1963), but their relation to cell renewal systems was not described. SHAW & BaTTLE (of. cit.), and Gatt- sorF (1964), among others, have reported that cells from the crypts of the digestive tubules replace the secretory absorptive cells of the tubule in C. virginica. However, this has not been closely examined and details are lacking. Thus, with the possible exception of the germinal epi- thelium of the gonad, no reports of mitosis, in relation to normal cell renewal systems, have been recorded for oyster tissues. The purpose of this paper is to describe two cell renewal systems observed in the gut of Crassostrea gigas (Thunberg, 1793). METHODS anp MATERIALS The basic cell renewal system of the gut epithelial cell was determined by microscopic examination of 25 oysters after fixation with Davidson’s fluid, routine tissue process- ' This study was made possible through a grant, UI-1039-03 (Shellfish Sanitation Training Grant) from the U. S. Public Health Service. 2 Part of a thesis in partial fulfillment of the requirements for a Doctor of Philosophy degree in Fisheries, University of Wash- ington. ing, sectioning, and staining. Six-micron sections were stained with Harris’ hematoxylin and eosin, Mallory’s an- iline blue collagen stain for oyster tissue (PAULEY, 1967), or methyl green-pyronin Y for differentiating nucleic acids (Gurr, 1965). Cell renewal systems for two different cell types were elucidated by noting the location of mitotic figures, pre-, and post-mitotic nuclei. Some quantitative data, relative to the frequency of mitosis, were obtained for gut epithelial cells by counting the total number of mitotic figures in 17 6 sections from each of 18 randomly selected oysters according to the following scheme: 3 consecutive sections were taken every 75 - 100 from a 6 mm section of the ascending limb from the same area in each oyster. Mitotic figures were defined as those cells that were clearly dividing (7. e., early meta- phase, metaphase, anaphase, or telophase) or had recent- ly divided and the 2 resulting cells had not separated. RESULTS anv DISCUSSION Only a brief description of the basic cell renewal system of the gut epithelial cell will be given since cell labeling with radioactive tracers — necessary for a more precise analysis — was not part of this study. Gut epithelial cell nuclei normally lie in a plane mid- way between the basement membrane and the distal por- tion of the epithelial cell (Figure /). Prior to cell division, the nucleus migrates to the distal portion of the cell where it subsequently divides (Figure 2). The mechanics of this process are not understood but are similar to that seen in mammalian epithelial cells. Once mitosis has oc- curred, the resulting 2 nuclei (Figure 3) move back to their normal position in the cell population. Tue VELIGER, Vol. 14, No. 2 a + a is ae 4 3 , ae SBA Figure 2 Figure 1: Oyster gut epithelium. Note that the epithelial cell nuclei normally lie midway between the basement membrane and the distal surface x 480 Figure 2: Mitosis (arrow) of an epithelial cell after nuclear mi- gration (X 1200) Figure 3: Two adjacent epithelial nuclei, formed after mitosis, still in the distal portion of the epithelium (X 1200) [Mrx] Figures 1 to 3 _ ie Tue VELIcER, Vol. 14, No. 2 [Mrx] Figures 4 to 6 Figure 6 Figure 4: Gland cell nucleus (arrow) located at the base of the gut epithelium (X 1200) Figure 5: Gland cell showing the glandular portion (arrow) ex- tending to the free surface of the gut epithelium (X 1200) Figure 6: Mitosis (arrow) of a gland cell (X 1200) Vol. 14; No. 2 THE VELIGER Page 203 Another renewal system in the gut involves gland cells. There are 2 types of gland cells in the gut of the oyster, secretory epithelial cells which contain coarse vesicular mucus granules and extend various distances from the free border toward the basement membrane, and the so-called eosinophilic cell (SHAW & BaTTLe, 1957). The latter is an elongated cell laden with coarse granules which may extend throughout most of the cell. The cell renewal system subsequently described. evidently is for the eosinophilic cell, although there is some doubt about this since the granules of the cell stain with basic, not acid dyes. The nucleus of this cell is very large (Figure 4), lies below the nuclei of the epithelial cells just above the basement membrane, and contains a prominent nucleo- lus and finely granular, basophilic cytoplasm. The glandu- lar portion of the cell extends to the free surface of the epithelium (Figure 5). Renewal involves simple mitosis of the nucleus without migration from the basal region (Figure 6). Statistical analysis of the data, obtained by counting 17 tissue sections from each of 18 oysters, revealed the following information (see Mix, 1970 for detailed anal- ysis) relative to mitosis of epithelial (not gland) cells in the ascending limb of the gut: 1) there was no significant difference in the number of mitotic figures per section between oysters; 2) there was no significant difference between the num- ber of mitotic figures from the anterior to the posterior portion of the 10 mm segment analyzed; 3) the average number of mitotic figures was 6.43 mi- toses per 6 section (n = 308; SD = 3.18; SE — 0.18) ; 4) the range of the average number of mitotic figures per tissue section per oyster was 1.60 - 10.00. Finally, it appeared in subsequent studies where oysters were sampled from an identical environment at varying time intervals, that the number of mitotic figures was correlated with temperature changes during tidal fluctu- ations. Thus, if a sample was taken after a prolonged high tide, during which the oysters were subjected to cold temperatures of Puget Sound seawater, the number of mitotic figures was lower than when samples were taken after low tides when warmer air temperatures may have caused increases in water temperatures. Literature Cited Ga.tsorr, PauL SIMON 1964. The American oyster Crassostrea virginica GMELIN. Fishery Bull. Fish & Wildlife Serv., U.S. Bur. Comm. Fish. 64: 480 pp.; 400 figs.; 46 tables Gurr, Epwarp J. 1965. ‘The rational use of dyes in biology and general staining methods. Williams & Wilkens, Baltimore, 422 pp. Hititman, Rosert E. 1963. An observation of the occurrence of mitosis in regener- ating mantle epithelium of the eastern oyster, Crassostrea vir- ginica. Chesap. Sci. 4 (4) : 172 - 174 Mix, Micuaer C. 1970. ‘The histopathological effects of ionizing radiation on the Pacific oyster, Crassostrea gigas. An examination of degenerative syndromes, cellular reparative mechanisms, and their relation to normal cell renewal systems. Ph. D. Thesis, Univ. of Washington, 168 pp. PauLey, GitBert B. 1967. A modification of Mallory’s aniline blue collagen stain for oyster tissue. Journ. Invertebrate Pathol. 9 (2) : 268 - 269 Suaw, Barsra L. «& HeLen I. BaTtTLe 1957. The gross and microscopic anatomy of the digestive tract of the oyster Crassostrea virginica (Gmelin) . Canad. Journ. Zool. 35: 325 - 347 YONGE, CHARLES MAurIcE 1926. Structure and physiology of the organs of feeding and digestion in Ostrea edulis. Journ. Mar. Biol. Assoc. U.K. 14: 295 - 386 Page 204 THE VELIGER Vol. 14; No. 2 Field Identification of Crab Predation on Shaskyus festivus and Ocenebra poulsonr (Prosobranchia : Muricidae) BY NICK FOTHERINGHAM Department of Biology, University of Houston, Houston, Texas 77004 SEVERAL CRAB SPECIES chip open gastropod shells to feed on their contents (MacaLHaes, 1948; SHoup, 1968). The prey, which may be either snails or hermit crabs, can seldom be identified by examination of the chipped shells. Since edible crabs are usually secretive creatures, direct observation of crab predation in rocky intertidal areas is difficult. However, an analysis of recapture data obtained during a three year study of the snails Shaskyus festivus (Hinds, 1843) and Ocenebra poulsoni (Carpenter, 1856) does provide indirect evidence of crab predation on living snails in the field. Shaskyus and Ocenebra populations were found in an intertidal boulderfield 4 mile north of Scripps Institution of Oceanography in La Jolla, California. The hermit crab Pagurus samuelis (Stimpson, 1857) inhabited the shells of deceased snails. Another resident of the boulderfield, the crab Cancer antennarius Stimpson, 1856, attacked living Shaskyus and Ocenebra in the laboratory, but no attacks by Cancer were observed during more than 500 hours of observation in the boulderfield. Shells chipped by crabs represented 8.5+2.2% and 21.3+3.3%, respec- tively, of field collections of Shaskyus (N= 575) and O- cenebra (N = 1129) shells inhabited by hermit crabs. A census of marked Shaskyus and Ocenebra shells was taken monthly for 39 consecutive months. Indirect evi- dence of Cancer attacks on living snails in the field was obtained by comparing the numbers of crab-damaged, marked shells observed per shell per month (shell-month) of observation during 2 time periods. The first period extended from the time that the snail was last seen alive until the time that its shell was first observed after its death. The second period extended from the time that the shell was first discovered after the snail’s death until the last time that the shell was seen in the field. A signif icantly higher rate of shell damage during the first period would suggest that the crabs were feeding on living or dying snails in addition to hermit crabs. Since both living snails and hermit crabs can be at risk during the first period, the test is conservative, 7. e., evidence favoring crab predation on living snails is concealed. Damaged Shaskyus shells were discovered at the rate of 4 in 561 shell-months during the first period and 1 in 151 shell-months during the second period; damaged O- cenebra shells were discovered at the rate of 12 in 1298 shell-months during the first period and 1 in 326 shell- months during the second period. The numbers of dam- aged shells can be treated as Poisson variables if the num- bers of shell-months in each period are made equal. ‘Their differences were tested by means of the table of significant differences in PEaRson & HartLey, 1966. To remain on the conservative side while equalizing the time periods, I reduced the first period rates to 1.08 in 151 shell-months and 6.28 in 326 shell-months for Shaskyus and Ocenebra, respectively. No significant differences between the rates for the 2 periods were found for Shaskyus, but the differ- ence for Ocenebra was significant (P < 0.04, one-tailed). This higher rate of discovery of damaged shells during the first period suggests that the crabs were feeding on Ocenebra as well as on hermit crabs. The thick varices on the Shaskyus shell resist chipping by crabs and probably account for the difference in the proportions of damaged shells for the 2 species. Literature Cited MacELHAES, HuLpDA 1948. An ecological study of snails of the genus Busycon at Beaufort, North Carolina. Ecol. Monogr. 18: 378 - 409 Pearson, E. S. « H. O. Hartiey 1966. Biometrika tables for statisticians. Vol. 1. Univ. Press, Cambridge; 235 pp. SHoup, JouHN B. 1968. Shell opening by crabs of the genus Calappa. Science 160: 887 - 888 Cambridge Vol. 14; No. 2 THE VELIGER Page 205 Thais emarginata (Deshayes): Description of the Veliger and Egg Capsule BY RENEE LeBOEUF Pacific Marine Station, Dillon Beach, California 94929 * (8 Text figures) INTRODUCTION Dimensions of shells are defined by the following crite- Thais emarginata (Deshayes, 1839) is a small gastropod abundant on rocky shores from Alaska to Mexico (Ric- KETTS & Cavin, 1962). It deposits eggs in a yellow, vase- shaped egg capsule. Thais emarginata undergoes non-pe- lagic development with the aid of nurse eggs. The only species of Thais extensively studied to date is Thais haemastoma floridana Conrad, 1837 by D’Asaro (1966). D’Asaro describes the egg capsule and its forma- tion, oviposition, and the embryology through the first planktotrophic veliger stage. He also gives an extensive summary of the work that has been done connected with the life histories of thaidids. In the present paper, the egg capsules and non-pelagic veligers of Thais emarginata are described. METHODS ann MATERIALS A total of 98 egg capsules was collected from rocky areas north of Dillon Beach, California, on July 31 and August 10, 1970. At the laboratory, the egg capsules were retained in 600 ml-capacity beakers in a refrigerator at 17° C. Embry- os were removed from the capsule and placed in Stendor dishes for observation. Eggs and embryos were kept at the same controlled temperature. The filtered sea water was changed daily. Terminology and criteria for measurements used in the description of the egg capsule are based on the generalized capsule shown in D’Asaro (1970). “Height is the distance from the apex to the basal membrane, width is the distance between the lateral edges at the widest point” (D’Asaro, op. cit., p. 416). * Permanent address: 7858 Burton Avenue, Rohnert Park, Cali- fornia 94928 ria: width is the transverse distance of the aperture at the widest point; length is the distance from the shell rim to the far edge of the body whorl. Measurements of the velum were taken at the widest point, from one lobe to the other. All measurements were made from live animals with an ocular micrometer on a compound microscope. Illus- trations were prepared from live animals, except for drawings of the shell which were made after the animal was removed. OBSERVATIONS Egg Capsule The egg capsule of Thais emarginata is vase-shaped, pale yellow in color, with a short solid peduncle and a longitudinal suture that extends from the top of the peduncle to the rounded apex (Figure 1). The peduncle is flattened transversely to the suture and bordered by lateral ridges. A basal membrane of the capsule attaches to the substrate. Capsules were found in crevices between Mytilus in mussel beds or directly attached to Mytilus shells. They were also found lower in the intertidal zone on exposed smooth rocks. The capsule wall consists of 2 layers: an outer leathery layer which gives the capsule its characteristic shape, and an inner, loosely attached membrane that lines the interior and completely surrounds the embryos and nurse eggs. The inner membrane is transparent and cellophane-like in quality. The escape aperture is capped with a hard, clear, gelat- inous plug that extends above the escape aperture and is slanted toward and leads to the suture. The substance Page 206 Wile WEUIGIER Vol. 14; No. 2 Figure 1 Egg capsule of Thais emarginata bm — basal membrane pl—plug Ir—lateral ridge su — suture p — peduncle of the plug appears to be identical with the inner lining of the capsule lumen. The average dimensions of the capsule are: height, 5.9 mm; width, 2.3mm; diameter, 2.2mm. In comparison with those of ‘Thais haemastoma and T. rustica Lamarck, 1819 (D’Asaro. 1966; 1970), the capsules of T: emargin- ata are rounded in cross section and show only a slight concavity on the side with the suture. Lateral ridges are found only on the peduncle. The capsules are clustered together in irregular rows. The number of capsules per cluster ranges from 3 to 300 (Roy Houston, personal communication). One capsule can be attached to another so that clusters may be 2- layered. Sutures are aligned in the same direction. Contents of the capsules vary from 64 to 750 eggs with an average of about 500 eggs. Most of these are unferti- lized and serve as nurse eggs for developing embryos. Each egg is spherical and appears to be enclosed in a fine vitel- line membrane. The average diameter is 180u. Early cleavage was not observed. The number of veligers found in the capsules ranges from 3 to 39, with an average of 16. The number of nurse eggs was found to be related to the developmental stage of the veligers. In the capsules of the earliest veli- gers there is an average of about 450 nurse eggs. In capsules containing the advanced veligers, there are no nurse eggs. A varying number of nurse eggs are present in capsules containing veligers between early and advanced stages. At early stages it was not possible to distinguish between eggs that would eventually develop and those that would remain as nurse eggs. Shells It was possible to some extent to determine the stage of veligers by examination of their shells. Observations were made on the shells of veligers in early, middle, and advanced stages of development. Average measurements were derived from 2 or more samples of empty shells, each collected from a healthy population of veligers. The embryonic shell or protoconch is colorless and transparent. Directly after metamorphosis, brown and yellow pigmentations become prominent. Although the apparent shape varies greatly according to orientation, larval shells of ‘Thais emarginata are simple and cup- shaped. Only 2 early veliger shells were obtained. The first measured 335 in length and 289, in width. The second measured 277 by 277. From a ventral view, the shells consisted almost entirely of aperture. The whorl was just beginning to develop. Both shells were very narrow in depth. The rim of the shells was smooth and faint stria- tions were evident. In the first shell, 59 of the lip con- sisted of a thinner, clear material without striations that appeared to be newly formed shell. This new formation was continuous around the shell, decreasing in width until it reached the whorl. It then extended 5m from the edge of the whorl (Figure 2). Sixteen mid-stage veliger shells have the following average dimensions: length, 550u; width, 525m. The Figure 2 Early veliger shell of Thais emarginata Vol. 14; No. 2 THE VELIGER Page 207 whorl has a ? turn. These have almost doubled in length and width. The appearance of the shell is similar to that of the early veliger shell, being clear, fragile, thin, and having some striations. This shell tends to collapse rather than break as do the more advanced shells. There is a heavy striation about midway down the shell. This marks the point where shell gland secretions end and mantle shell Figure 3 Mid-stage veliger shell of Thais emarginata a: ventral b: right side c: left side secretions begin. The average length of shell secreted by the shell gland is 325, which roughly corresponds to the total length of the early veliger shells (Figure 3). Twenty-five advanced veliger shells have the following measurements: length, 775; width, 700p. There is one complete whorl. The aperture takes up a little more than half of the total length of the shell. The rim has become more striated, but remains smooth. In all cases, the stri- ations are faint (Figure 4). DESCRIPTION or VELIGERS Four veliger stages are described. Sequential time of de- velopment could not be monitored in this study because embryos removed from the egg capsule died within 2 days. Further, each cluster of egg capsules contained capsules with embryos in different stages of development so that following the development of veligers from clusters of capsules was not feasible. Earliest Veliger The body of the earliest veliger is round and measures 210 - 230 in length. These veligers have considerable yolk and are often difficult to distinguish from broken nurse eggs, both of which are yellow in color. Three ciliated areas are present on the embryo. The first ciliation occurs along a cephalic lobe. On one edge of the lobe is the second ciliated region, a protruding sensory area. These cilia are twice the length of cephalic lobe cilia. A third group of cilia occurs on a small pro- trusion, the shell gland, found laterally between the poste- rior of the animal and cephalic lobe (Figure 5). Larval kidneys develop dorsolaterally to the cephalic lobe on each side of the embryo. These are produced by ectodermal proliferations (D’Asaro, 1966). Figure 4 Advanced veliger shell of Thais emarginata b: left side a: ventral c: dorsal Page 208 THE VELIGER Vol. 14; No. 2 Figure 5 First stage veliger of Thais emarginata asr — apical sensory region Ik — larval kidney sg — shell gland poll S— sg er ae a 100, —— Figure 6 Second stage veliger of Thais emarginata ap — apical plate asr — apical Ik — larval kidney pg-—pedal ganglia ma-—mantle anlage s—stomodaeum st — statocyst sensory region pa — pedal anlage sg —shell gland Second Stage Veliger This stage measures 240 - 370p in length, is ovoid in shape, and still with a great deal of yolk. It is capable of rotation and forward and backward movement (Figure 6). It is suspected that torsion occurs during the second veli- ger stage and is completed by the third stage. Evidence for this comes in the similarity of the second veliger stage to the torsional pause veliger described by D’Asaro (1966). The cilia have developed further and cover considerably more area. The mantle anlage, stomodaea, pedal ganglia, and statocyst anlage have developed, while the larval kid- neys have enlarged. The stomodaeal invagination is vis- ible and seen to be deep enough to touch the anterior wall of the archenteron. Because of this invagination, the cephalic plate has been divided into 2 areas: an apical plate region that will eventually develop into the velar lobes, and a foot rudiment. Ventral to the stomodaeum on the foot rudiment is the pedal ganglion. Statocysts arise as invaginations dorsal to the pedal ganglia. Active oral ciliation is present in the stomodaeum and laterally on either side of the cephalic region and along the foot from the ventral lip of the stomodaeum to the anterior end of the pedal anlage. The shell gland is heavily ciliated. This region outlines the anlage of the post-torsional dorsal mantle lip. The protoconch is formed from secretions of the shell gland. Third Stage Veliger The body of the third stage veliger is more elongated and measures 630-660 in length. The shell encloses about one third of the body. The apical plate has differ- entiated into 2 small velar lobes. These measure 500u from lobe to lobe and are bordered by cilia 40 in length. This embryo uses the cilia of the velar lobes and is capable of gliding movements in any direction (Figure 7). The entire oral region is ciliated. A short esophagus, usually filled with ingested nurse eggs, is visible. The esophagus probably leads into the gastric stomach, but because the body mass contains so much yolk, it is not possible to discern any additional internal structure. A larval kidney, made up of vacuolated cells, lies direct- ly behind each velar lobe. Towards the end of this stage, the larval kidneys decrease in size. The adult kidney, which is yellow in color and developing in the pleural groove, is presumably functional in the advanced veliger stage. The rhythmically beating heart is found just poster- ior and dorsal to the left larval kidney. During this stage the mantle lip grows and becomes ciliated. Pedal ganglia are not evident. Statoliths are present in the statocysts dorsal to the mouth and between the larval kidneys. Vol. 14; No. 2 THE VELIGER Page 209 Figure 7 Third stage veliger of Thais emarginata a: ventral b: left side Ik — larval kidney m— mouth ml — mantle lip ak — adult kidney e — esophagus f — foot lh — larval heart sl — statolith The foot is clearly differentiated from the oral area, The columella muscle is located at the apex of the shell is small and ciliated. It is not used for locomotion. An whorl. Muscle strands are difficult to trace due to the operculum was not observed. closeness of the mantle to the body mass. Figure 8 Fourth stage veliger of Thais emarginata a: ventral b: left side Ik — larval kidney m — mouth ml-—mantle lip ak — adult kidney e— esophagus f — foot Th — larval heart o — operculum sl — statolith Page 210 External changes in the cephalic region include for- mation of the right tentacle anlage, from which the right tentacle develops. Several veligers were observed feeding on nurse eggs. A nurse egg was first rotated by the velar cilia until the egg became irregular in shape. The velar cilia seemed to weaken the membrane around the nurse egg, at which time oral cilia pulled the yolk through the mouth and into the esophagus. Advanced Stage Veliger The advanced veliger is almost entirely surrounded by a shell with one complete whorl. It has a rounded body and measures up to 1150y in length. Among the most obvious external characteristics are the velar lobes, the foot which is extended over the whorl of the shell, the operculum, and the larval heart. The velar lobes measure up to 800p from lobe to lobe and are bordered by cilia 47 in length. These are the main locomotory organs and can be folded, twisted, and con- tracted by the larva. The foot is completely ciliated and has several tactile bristles 3 in length on the tip. The operculum now present is thin, clear, fragile and does not extend beyond the foot. At full expansion, the larval heart occupies most of the mantle cavity and extends into the right pleural region. The beat is irregular. The velum, foot, and heart extend out from the shell (Figure 8). The ventral mouth lies between the velar lobes, is com- pletely ciliated and leads to a ciliated esophagus. The esophagus enters the gastric stomach on the ventral side. There is an oral ciliary band ventral to the mouth, ex- tending between the larval kidneys. The adult kidney in the pleural groove is yellow and ovoid in shape. The larval kidneys are still present behind the velum. Both statocysts are completely developed and are dorso- lateral to the mouth. The columella muscle is well defined and has 2 shell attachments. Additional musculature is obscured by yolk. Advanced veligers usually lie on their side, either right or left, so that one velar lobe is positioned down and the other up. Occasionally they are found lying on their dorsal side so that the velar lobes are widespread and the mouth can be seen. This positioning has to do with the bulkiness of the shell. Movement is clumsy and mostly rotational. DISCUSSION Identification of veliger characteristics in this paper is based on the work of D’Asaro (1966) on Thais haema- THE VELIGER Vol. 14; No. 2 stoma floridana which has a planktotrophic veliger stage. Early larval development of T: emarginata is similar to that of T: haemastoma. The most evident variation is in the development of the protoconch and operculum. Both of these structures appear earlier in T: haemastoma devel- opment. Because of the large yolk reserve, the egg diameter and advanced veliger stage of Thais emarginata are larger than the egg and corresponding veliger after the first planktotrophic stage of T: haemastoma. The amount of yolk reserve in T: emarginata is surprising and makes organogenic work difficult without resorting to histologi- cal techniques. According to RickeTTs & Carvin (1968) there is not enough yolk to maintain the embryos through hatching time. “Consequently they eat each other until only one — and that one presumably cock of the walk — is left to emerge from the capsule into a world where its chances of survival are still poor” (Ricketts « Carvin, 1968: 212). While this may be true in some cases, it was ob- served in the present study that as many as 16 larvae develop to the crawling stage and hatch from the egg capsule. Embryos do ingest all of the available nurse eggs, but further growth seems to be at the expense of their own yolk reserve. Only twice was cannibalism observed, and this occurred with embryos removed from the egg capsule. A peculiar feature in the growth pattern of Thais emar- ginata was observed in 21 of 85 (25%) capsules. Veligers contained within a single capsule tended to vary in size or stage of development or both. The greatest develop- mental range was found in a capsule containing 10 veli- gers. Six of these were advanced, 2 were third stage, and 2 were second stage. Whether the dissimilarities were due to differences in feeding rates, fertilization times, or simply to individual developmental rates was not determined. ACKNOWLEDGMENTS It is with pleasure that I acknowledge the help of Dr. James Blake and Mr. David Montgomery who gave in- valuable advice on observation procedures and critized this manuscript. My thanks also go to the National Science Foundation for financial support derived from N.S. F Grant GB-19344. Vol. 14; No. 2 THE VELIGER Literature Cited D’Asaro, Cuaruzes N. 1966. The egg capsules, embryogenesis, and early organogen- esis of a common oyster predator, Thais haemastoma floridana (Gastropoda: Prosobranchia) . Bull. Mar. Sci. 16 (4): 884 - 914 1970. Egg capsules of prosobranch mollusks from South Florida and the Bahamas with notes on spawning in the laboratory. Bull. Mar. Sci. 20 (2) : 414 - 440 Ricketts, Epwarp F. & Jack CaLvin 1968. Between Pacific tides. 4th ed., rev. by J. W. Hepc- PETH. xiv +614 pp.; illus. Stanford Univ. Press, Stanford, Page 212 THE VELIGER Vol. 14; No. 2 METHODS & TECHNIQUES A Mesofaunal Collecting Kit for SCUBA Work in Frigid Waters BY J. SHERMAN BLEAKNEY Biology Department, Acadia University Wolfville, Nova Scotia, Canada (1 Text figure) THE SELECTIVE COLLECTION by hand of small organisms (0.5mm to 2cm) by SCUBA divers is difficult under the best temperature conditions and becomes extremely so at low temperatures when neoprene gloves or mitts must be worn. An apparatus “The Acadian SOCK” (Single Operation Collecting Kit) which overcomes this difficulty has been previously described, but an efficient method for underwater transport of a series of SOCKs had not been devised at that time (BLEAKNEY, 1969). The Acadian SOCK Rack diagrammed in Figure 1 has proven most satisfactory under winter diving condi- tions in Nova Scotia. The construction is of perspex, ex- cept for the flexible rods which are nylon for it was found that perspex rods became brittle in icy water. A diver wearing thick mitts or gloves can easily remove a SOCK by tipping it back and sliding it up the rod. It is replaced by slipping the small tube over the rod, bending the rod away from the upper disc, sliding the SOCK down and letting the rod snap back into place. This meth- od eliminates struggling with any rubber or mechanical clamps. With such a rack the SOCKs can be numbered and kept separate, they are instantly available and their contents can be examined and compared. The central cylinder (the handle) serves as a collecting jar for larger specimens or colonial forms, and the entire unit, if kept chilled, serves for both transport and storage. A writing slate can be an added refinement by simply sanding the perspex base. Small nudibranchs, pteropods, ctenophores, polychaetes, - crustaceans and such are collected by removing a SOCK from the rack, slowly depressing the rubber diaphragm (which is fastened over the open end) with the index finger or thumb, placing the lateral spout near the organ- ism, then quickly releasing the pressure, thereby sucking the specimen into the SOCK. The opportunity to design and test this collecting ap- paratus was made possible through financial support from a National Research Council of Canada Operating Grant. Literature Cited BLEAKNEY, J. SHERMAN 1969. A simplified vacuum apparatus for collecting small nudibranchs. The Veliger 12 (1): 142-143; 1 text fig. (1 July 1969) (on facing page —>) Figure 1 Design of an underwater eight-unit rack for Acadian SOCK vacuum collecting apparatus. A section of perspex tubing cemented to the side of a SOCK fits over a flexible nylon rod, which has been cemented into a base plate so that the rod presses firmly against the upper perspex disc. The long central tube is cemented into the base plate and serves underwater as a handle, and when corked as a collecting jar for larger specimens. The insertion of colonial hydroids or algae into this chamber is facilitated by the four small drain holes. (A rubber diaphragm cap over the SOCK has been omitted from the drawing.) Vol. 14; No. 2 Wels WEILIGIEIR Page 213 Pe a ata er ee ee BBE ENS <—— }#’ Plexiglass Tubing 13” O.D. X 12” long 3/16” Dia. Nylon Sat Dowelling 22” long 3/16” X54” O.D. <— Plexiglass Page 214 NOTES & NEWS The Reinstatement of Hypselodoris agassizi (Bergh, 1894) (Mollusca : Opisthobranchia ) BY GALE G. SPHON Los Angeles County Museum of Natural History Los Angeles, California 90007 Pruvot-For (1951) syNnonymizep Hypselodoris agassizt (Bergh, 1894) with H. californiensis (Bergh, 1879) because the 2 species are superficially similar in appear- ance. However, there are consistent external differences in both color and pattern that I consider warrant the re- instatement of H. agassizi as a valid species distinct from H. californiensis. Hypselodoris californiensis is solid blue with large yel- low dots or streaks and a single, continuous yellow stripe along the border of the mantle. A lighter colored yellow stripe occurs around the edge of the foot. Hypselodoris agassizi has the same basic dark blue color as H. califor- niensis, but has many more and much smaller yellow dots or streaks. Along the mantle border there occur 2 stripes. The innermost is light green and the outer one is the same yellow as the dots. Between the 2 stripes is an area of navy blue or black. The stripes in the approxi- mately 50 specimens and photographs I have seen of this species have been interrupted in the mid-dorsal re- gion. There is a continuous light green band around the edge of the foot. In H. californiensis the rhinophores are a navy blue or black, while in H. agassizi they are the same color but have a golden stripe down the posterior side that runs from the tip to the base. The gills in H. californiensis are the same navy blue or black as the rhino- phores while H. agassizi has white gills that are tipped with black, In his original description of Chromodoris agassizt, Bergh mentions that the bands may be interrupted in the lateral parts of the back and also the presence of a nar- row green band along the side [?foot]. Bergh makes no actual comparison with his earlier species, C’. californi- ensis, in the text. However, he does present drawings of some of the lateral radular teeth for both species. Hypselodoris californiensis ranges from at least as far north as Monterey, California, southward to La Paz, Mexico, and throughout the Gulf of California. Hypselo- doris agassizi was originally described from Panama and THE VELIGER Vol. 14; No. 2 ranges northward to Puerto Penasco, Sonora, Mexico, at the northern end of the Gulf of California. To the best of my knowledge, H. agassizi has not been collected from the Baja California side of the Gulf. The 2 species have now been taken together from Punta Lobos and Guaymas, Sonora, Mexico. Recently, the radulae of the 2 species were examined and found to be very similar. Both had bicuspid lateral teeth, proving them to be Hypselodoris rather than Chro- modoris (which does not have bicuspid lateral teeth). It should be pointed out that both species are illustrated in Marcus & Marcus, 1967 (p. 177, fig. 30 is Hypselo- doris californiensis; fig. 31 is H. agassiz.). My thanks are due to Mrs. Eveline Marcus for criti- cally reading the manuscript. Literature Cited Bercu, Lupwic SopHus RupboLr 1879. On the nudibranchiate gasteropod Mollusca of the north Pacific Ocean, with special reference to those of Alaska. Proc. Acad. Nat. Sci. Philadelphia 31: 71 - 132 1894. Reports on the dredging operations off the west coast of central America to the Galapagos, to the west coast of Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on by the U.S. Fish Commission steamer “Alba- tross”, during 1891, Lieut. Commander Z. L. Tanner, U.S.N., commanding. XIII. Die Opisthobranchien. Bull. Mus. Comp. Zool., Harvard Univ. 25 (10): 125 - 233; plts. 1-12 (October 1894) Marcus, EvetingE DuBois RayMonp & Ernst Marcus 1967. American opisthobranch mollusks. Stud. Trop. Oce- anogr. Miami 6: viii + 256 pp. Pruvot-Foi, ALICE 1951. Révision du genre Glossodoris EHRENBERG. Conchyl. 91 (3): 76 - 164 Journ. de Eubranchus misakiensis Baba, 1960 (Nudibranchia: Eolidacea) in San Francisco Bay BY DAVID W. BEHRENS San Francisco State College, San Francisco, California * Tuer EOLID NUDIBRANCH, Eubranchus misakiensis Baha, 1960, has been observed by the author to occur seasonally at the San Francisco Municipal Marina (Lat. 37°48’31” 1 Permanent address: 732 Gonzalez Drive, San Francisco, Cali- fornia 94132 Vol. 14; No. 2 THE VELIGER Page 215 N; Long. 122°26'28” W). It was first collected at the same locality in April, 1962 by Miss Joan E. Steinberg, who tentatively identified it, but expressed the need for positive identification of the animal. The eastern Pacific specimens, measuring up to 11 mm in length and 2 mm in width, were much larger than those described from Japan by Baba. His largest specimens were only 3-5 mm in length. Accordingly, 2 preserved specimens and a photo- graph of a living specimen were sent to Dr. Kikutaré Baba, who confirmed the identification as Eubranchus misakiensis. Eubranchus misakiensis is a very common inhabitant in the San Francisco Municipal Marina throughout the spring and summer months, apparently reaching popu- lation peaks in late May and in August. It is always associated with Obelia sp., on which it presumably feeds. According to my observations, it appears that the popula- tion density of E. misakiensis closely follows that of the Obelia. In the field, the most striking evidence of this small nudibranch is its conspicuous white, linear egg mass at- tached to the stalks of Obelia. The egg masses are ribbon- like, slightly curved, and measure approximately 2 - 4mm in width and 7-11mm in length. Those which were collected in San Francisco Bay are in general agreement in size, shape, and color with those described by HaMa- TANI, 1961. Eubranchus misakiensis may be mistaken for Capellinia rustya Marcus, 1961 [= Eubranchus occidentalis Mac- Farland, 1966 (see Rotter, 1970) ]. Although both spe- cies have irregularly inflated cerata, the color and shape of the liver diverticula in each are quite characteristic. The liver diverticula of EF. misakiensis are chocolate-brown in color, and each diverticulum within a ceras contains a large boss at midlength. In contrast, the diverticula of C’. rustya are whitish-pink and each ceratal branch bears 2 or 3 rings of large tubercles. Another obvious difference is that the foot corners of Eubranchus misakiensis are in the shape of short horns whereas the foot corners of Capellinia rustya are rounded. A further characteristic is the body color: E. misakiensis has a yellowish-white ground color with large chocolate- brown freckles; C’. rustya is translucent white with diffused olive-green spots. Eubranchus misakiensis is currently recorded by Baba to occur on the east coast of Honshu, Japan; Misaki, Saga- mi Bay; Osaka Bay; Mukaishima, Inland Sea of Seto. This is the first recorded occurrence of E. misakiensis in eastern Pacific waters. Several specimens are presently in the collection of the California Academy of Sciences in San Francisco. I would like to extend my sincere thanks and appreciation to Miss Joan E. Steinberg and Dr. Albert Towle, for their critical comments on the manuscript, and to Dr. Kikutard Baba for the information he so graciously provided. Literature Cited Basa, KikuTARO 1960. Two new species of the genus Eubranchus from Japan (Nudbranchia — Eolidacea). Publ. Seto Mar. Biol. Lab. 8 (2): 299 - 303 (1 December 1960) In press. Review of the anatomical aspects of Eubranchus misa- kiensis Baba, 1960 from Mukaishima, Japan (Nudibranchia: Eolidiodea: Eubranchidae) . Venus, Japan. Journ. Malacol. Hamatant, Iwao 1961. Notes on the veligers of Japanese opisthobranchs (4). Publ. Seto Marine Biol. Lab. 9 (2) : 353 - 361 (1 December 1961) MacFarianp, FRanK Mace 1966. Studies of opisthobranchiate mollusks of the Pacific Coast of North America. Mem. Calif. Acad. Sci. 6: xvi + 546 pp.; 72 plts. (8 April 1966) Marcus, Ernst 1961. | Opisthobranch mollusks from California. 3 (Suppl.) (I): 1-85; plts. 1-10 Rouier, Ricuarp A. 1970. A list of recommended nomenclatural changes for Mac- Farland’s “Studies of opisthobranchiate mollusks of the Pacific Coast of North America.” The Veliger 12 (3): 371-374 (1 January 1970) The Veliger (1 February 1961) New Record of a Color Variation in Spurilla oliviae BY GARY C. WILLIAMS 267 Oak Manor Drive, Fairfax, California 94930 (1 Text figure; 1 Map) On JuNE 9, 1970, A SINGLE SPECIMEN of a color varia- tion for the aeolid nudibranch, Spurilla oliviae (MacFar- land, 1966) was collected by the author at Duxbury Reef in Marin County, California (Lat. 37°53’ N; Long. 122° 42’ W). The animal was found crawling on the rhodo- phyte Iridea sp. about 3 inches beneath the water’s sur- face. The specimen was located in a large zone-three tidepool dominated by the surf grass Phyllospadix and various coralline algae. The tide pool is one of 2 such pools on the wave-swept southern projection of the shale reef known locally as area “C.” Page 216 The slug’s cerata are a very light salmon pink in life, turning white when preserved in 10% formalin. This light rosy hue of the cerata is in contrast to the vivid orange of other specimens of the same species collected from Duxbury in recent years. The ground color of the body of the variant is white as are the cephalic tentacles. The rhinophores are orange and similar to those of the i we ott ras ce < & any cy Sse ob a: ah Sao wf des RO se Somes: a eR “4ufszeOil 7r/aeS) SBVss(0)2} 9.6+0.9 <2.2 C2) 7/28 7/40) 3) Ge 7/ S(O.) <1.0 6.3+0.5 128.0450 101+0.1 <2.2 261.0+ 1.0 ASX TAP OAR OS ROAR | Station Vol. 14; No. 4 THF VELIGER Page 371 Chromium and Manganese Chromium was found in relatively high amounts in bodies at two localities, in Acmaea at Fort Point (B) and in Tegula at Fisherman’s Wharf (F). Body levels may relate to possible contamination from automobiles at Fort Point (see lead, below), and the presence of small craft in Monterey Harbor (see copper, above). Tapes at Coyote Point (A) is also notable for high chromium levels. High manganese levels in bodies and shells were found in animals from muddy areas: in Mytilus and Tapes at Coyote Point (A) and in Mytilus at Elkhorn Slough (D). Values were also high in Acmaea from Fort Point (B) and White’s Point (K). Manganese levels in shells of Tegula were first documented by Krinsery (1959) who found 4-6 ppm in shells of live California animals, and 13 - 17 ppm in fossilized specimens. Most values in the present study are above the range given for live animals. Manga- nese has a role as an activator of enzyme systems that is well established. Lead Detection of lead in shells was partially handicapped by high spectrophotometric limits. High values in bodies were found in Mytilus californianus at Half Moon Bay (C), both species of Mytilus at White’s Point (K), and especially in Acmaea at Fort Point (B), 931 ppm. These are animals that live well up in the intertidal zone, and, near cities, they are exposed to atmospheric fallout of lead from automobile exhaust for much of the day. Animals found at Half Moon Bay were in the vicinity of a sewer outfall. White’s Point, besides being directly inshore of the Los Angeles County sewer outfall, is close to regions of heavy traffic in Los Angeles and Long Beach. Fort Point attracts an estimated 60 - 100 tourist automo- biles per day on weekends, many of which have been seen to park within 5 feet of the wall on which Acmaea were found. In addition, this locality is situated directly under the Golden Gate Bridge. The very high levels of Pb in Ac- maea digitalis bodies at this point perhaps reflect not only the high lead fallout from auto exhaust, but also the fact that this species lives on, and feeds from rock surfaces not thoroughly rinsed by their submersion at high tides each day. Lead has no known usefulness in biological systems, and is known to inhibit certain enzymes. Cadmium and Zinc Cadmium in shells was highest in Mytilus at Carmel Bay (I), in Tapes at Coyote Point (A), and Tegula at Fisherman’s Wharf (F) and Carmel Bay (I). Body values are most sizable in Acmaea at White’s Point (K) and Thais at the Wharf (F). Cadmium is toxic to living sys- tems because it can replace zinc, an important component of metalloproteins, such as carbonic anhydrase. Zinc metal in the environment, however, often contains sub- stantial amounts of cadmium as a contaminant, which might explain the close relationship between levels of cadmium and zinc in bodies of Acmaea and Thais. Zinc was the most abundant trace metal of those studied in the soft parts of mollusks, as it is in sea water; values in the body were at least 20 times higher than in the shell. High amounts of zinc in bodies of Thais at Fisherman’s Wharf (F), 1700 ppm, and of Acmaea at White’s Point (K), 763 ppm, may be related to location. In motor- driven marine vessels, it is almost universal to have zinc blocks fastened to the hull, near the propeller to protect it and the drive shaft from electrolysis in sea water. These blocks, higher in the electromotive-force series than iron and brass, slowly go into solution and need replacement at regular intervals. Fisherman’s Wharf, as noted earlier, lies in a harbor, while at White’s Point (K) the collecting site is less than 4 miles from the Los Angeles-Long Beach Harbor, where many hundreds of boats are moored. Zinc has been found to be concentrated by brown algae (BLAcK & MircuHe tt, 1952) 40 times that in sea water. Mytilus edulis It is perhaps noteworthy that levels of trace metals in Mytilus edulis from California show a number of agree- ments with those of the same species in New Zealand (Table 3) as determined by Brooks «& Rumssy (1965). Table 3 Trace metals (ppm dry weight) in soft portions of whole bodies of Mytilus edulis. Values show approximate means followed by ranges in parentheses. B. Levels found by Brooks & RuMsBY present study. A. Levels found in (1965) in New Zealand. N Ag Cu Cr California 24 1(<1-1.3) 7(5-11) 4(<2-8) New Zealand 6 1(0.1-1.3) 9(8-11) 16(9-24) Mn Pb Cd Zn 16( 6-28) 5(2-8) 5(3-7) 284(204-341) 27(12-38) 12(3-25) 10(10) 91( 50-180) Page 372 Differences in localities and methods of analysis, however, should be taken into consideration in any comparisons made. SUMMARY Determinations of silver, cadmium, chromium, copper, manganese, lead, and zinc were made by atomic absorp- tion spectrophotometry on 7 species of Mollusca in the genera Acmaea, Tegula, Thais (gastropods), and Mytilus, Protothaca, and Tapes (bivalves). Eleven regions along the California coast from San Francisco Bay to Los Ange- les were included. Separate analyses were performed on shells and soft portions of whole bodies. Highest levels, above 900 ppm lead in bodies of Acmaea digitalis, 570 ppm copper and 1700 ppm zinc in bodies of Thais emar- ginata, have raised the question of causes for these un- usual concentrations. ACKNOWLEDGMENTS The author wishes to express thanks to the faculty, staff and graduate students of Hopkins Marine Station, especi- ally to Dr. Donald P. Abbott for his encouragement and many indispensable suggestions, both during research and while writing the manuscript. Dr. John H. Martin pro- vided additional helpful criticism and a general knowledge of the problems of trace metal analysis. Also to Mr. George Knauer and Mr. S. John Chang I owe gratitude for inspiration furnished during this study. Literature Cited Biack, WILLIAM AirpD PEDEN & RoBERT LYELL MITCHELL 1952. Trace elements in the common brown algae and sea water. Journ. Marine Biol. Assoc. U. K. 30: 575 - 584 THE VELIGER Vol. 14; No. 4 Brooks, Rosert R. « Martin Grecory RuMSBY 1965. The biogeochemistry of trace element uptake by some New Zealand bivalves. Limnol. Oceanogr. 10: 521 - 527 Crark, F W. & W. C. WHEELER 1922. Inorganic constituents of marine invertebrates. U.S. Geol. Surv. Prof. Paper 124: 1 - 62 CorneEc, ERNEST 1919. Etude spectrographic de cendes de plantes marines. Compt. Rend. hebdom. Acad. Sci. Paris 168: 513 - 514 Drinnan, R. E. 1966. Observations on the accumulation of heavy metals by shellfish in the estuary of the Miramichi River, N.B. | Manu- script Ser., Fish. Res. Brd. of Canada (May 1966) Go pBerc, Epwarp D. 1965. | Review of trace element concentrations in marine or- ganisms. Puerto Rico Nucl. Center, 535 pp. Harpy, Harrier Louise 1966. ‘Toxicology of lead. Sympos. environm. lead contamin. Publ. no. 1440, U.S. Publ. Health Serv., Washington, D.C. (March 1966) Hovustou, W. F, J. W. Woop « E. R. JEFFERIES 1954. The toxicity of zinc or cadmium for Chinook salmon. Oregon Fish. Comm. Briefs 5 (1) KrinsELy, Davip 1959. Manganese in modern and fossilized gastropod shells. Nature, London 183: 770 - 771 (14 March 1959) McFarren, Fart FRANCES, JAMES EDWARD CaMPBELL & J. B. ENGLE 1961. The occurrence of copper and zinc in shellfish. Proc. 4th Shellfish Sanit. Wrkshp., U.S. Publ. Health Serv., Append. R, p. 229 Nicuoiis, Grorrrey DENNis, H. Curt « V. T. BowEN 1959. Spectrographic analysis of marine plankton. Oceanogr. 4: 472 - 478 SuustTer, Cart NaTHANIEL, Jr. « BENJAMIN H. PRINGLE 1968. Effects of trace metals on estuarine molluscs. Proc. 1st Mid-Atl. Indust. Waste Conf., Univ. Delaware CE-5: 285 to 304 Vinocrapoy, A. P. 1953. | The elementary chemical composition of marine organ- isms. Yale Univ., New Haven, Conn. (Sears Foundat. for Marine Res.) 640 pp. Limnol. Vol. 14; No. 4 THE VELIGER Page 373 Duration of Useful Survival of the Isolated Radula Protractor of the Gastropod Busycon canaliculatum BY ROBERT B. HILL Department of Zoology, University of Rhode Island, Kingston, Rhode Island 02881 (3 Plates) IN A NUMBER OF EXPERIMENTAL designs gastropod buccal muscles are expected to be active in isolation for periods of hours or days. For instance, in bioassay procedures, radula muscle complexes have been kept in a water bath for 48 hours (Feper & Lasxer, 1968). Similarly, the iso- lated radula protractor of Busycon (Busycotypus) canali- culatum (Linnaeus, 1758) has been used for hours in a sucrose gap (Hitt, GreenBerc, Irnisawa & Nomura, 1970) or for periods of up to 20 hours in a sea water bath (Hitt, 1970). It becomes appropriate to ask whether physiological variations should be attributed to experi- mental manipulations or to decline in the condition of the preparation. A suitable parameter for assessing decline of the preparation should be maximal for the condition of the preparation at a given time (7. e., not susceptible to variation in threshold or post-tetanic potentiation) and yet should not excessively fatigue the preparation. Sub- fusion tetanus thus seemed preferable to twitches or to complete tetanus. METHODS The isolated radula protractor was set up in a bath of aerated natural sea water (Hitt, MARANTZ, BEATTIE & LockuHarT, 1968) maintained at 9° or 10° C. Isotonic contractions were recorded on a smoked drum. An elect- ronic stimulator was used to deliver shocks between two chlorided silver electrodes, one tied to the odontophore end of the muscle and the other in the sea water at a point corresponding to the radula end of the relaxed muscle. The standard stimulus was 80 V (40 ma) for 8 msec. RESULTS At the temperatures used it was found that tetanus fusion was consistently complete at 5 shocks per second (Figure JA) and that there was no mechanical wave summation at 0.2 shocks per second (Figure /B). The lowest frequen- cy at which summation was evident was 0.5 shocks per second (Figure 2) and shortening was doubled by the in- complete tetanus at 1.3 shocks per second (Figure 2). After a few preliminary trials with repeated tetanization over long periods of time, 1 shock per second was chosen as standard frequency, since it consistently remained below tetanus fusion frequency as long as the muscle was viable. Pairs of muscles from the same animal were set up in identical baths and a rocking key was used to determine whether the stimulus was sent to one muscle or the other. The same lever arm ratio was used throughout and short- ening was reported simply asmm on the drum. One muscle was stimulated for one minute at hourly intervals from 9 A. M. to 5 P.M. for 6 days. During the first 5 days (Fig- ure 3) shortening fluctuated during the day between 45 mm and 70 mm. On the sixth day, shortening fluctuated between 15 mm and 20 mm during the day. The control muscle was stimulated for one minute at hourly intervals between 1 P M. and 5 P.M. of the sixth day only. Short- ening fluctuated between 45mm and 75 mm. When the muscle was stimulated at short intervals (10 minutes) it was found that no significant deterioration in performance could be measured over one day. The latter experiment was repeated nine times with consistent results. DISCUSSION anp SUMMARY It may be said with confidence that the isolated radula protractor does not deteriorate significantly in its ability to respond to stimulation over the period of one day. Over longer periods, a repetitively stimulated muscle may de- teriorate more quickly than a control maintained in sea water. After six days, the repetitively stimulated muscle attained a maximal 75 mm shortening. Page 374 THE VELIGER Vol. 14; No. 4 ACKNOWLEDGMENTS I wish to thank Mrs. Linden Vargish for technical assist- ance. Literature Cited FEepER, Howarp M. « REUBEN LASKER 1968. A radula muscle preparation from the gastropod, Kelletia kelletii, for biochemical assays. The Veliger 10 (3): 283 to 285; 1 text fig. (1 January 1968) Hitt, Rosert BENJAMIN 1970. Effects of postulated neurohumoral transmitters on the isolated radula protractor of Busycon canaliculatum. Comp. Biochem. Physiol. 33: 249 - 258 Hitt, Rosert Benjamin, Micuaey J. GREENBERG, Hirosni Iris- Awa & HiromicuH1 Nomura 1970. Electromechanical coupling in a molluscan muscle, the radula protractor of Busycon canaliculatum. Journ. Exp. Zool. 174: 331 - 348 Hitt, Ropert Benjamin, EvizaBETH Marantz, B. BEATTIE & J. LockHart 1968. | Mechanical properties of the radula protractor of Busy- con canaliculatum. Experientia 24: 91 - 92 Explanation of the Plates Figure 7: A. Stimulation of the isolated radula protractor at 1, 2, 3, and 5 shocks per second. B. Stimulation of the isolated radula protractor at 0.2, 0.5, and 1 shock per second. Figure 2: Increase in tetanus fusion between 0.5 and 1.3 shocks per second. Figure 3: During a six-day period the isolated radula protractor was tetanized at 1 shock per second for one minute at hourly inter- vals ten times each day. Ordinate, shortening in mm on the drum. Abscissa, days. Representative examples of kymograph records inset. Lightly shaded area in bars represents amplitude of individual sub- fusion responses. THE VELIGER, Vol. 14, No. 4 [Hitt] Figure / Radula protractor Busycon canaliculatum Tue VE .IcER, Vol. 14, No. 4 [Hixxy] Figure 2 Radula protractor Busycon canaliculatum 10°C Tue VELIGER, Vol. 14, No. 4 [Hitt] Figure 3 Vol. 14; No. 4 THE VELIGER Page 375 Structure and Function of the Alimentary Tract of Batillaria zonalis and Certthidea californica, Style-Bearing Mesogastropods ANDREW L. DRISCOLL * Pacific Marine Station, Dillon Beach, California 94929 (8 Text figures) INTRODUCTION THE FAMILY Potamididae is represented on the Califor- nia coast of North America by two genera, each repre- sented by a single species: Batillaria zonalis Bruguiére, 1792, and Cerithidea californica Haldeman, 1840. The use of the name Batillaria zonalis is in accordance with the conclusions of HANNA (1966). References in the literature concerning these two species are primarily taxonomic with the exception of two papers on the gross morphology of C. californica by Bricut (1958, 1960). This study describes the structure and function of the alimentary tracts of Batillaria zonalis and Cerithidea cali- fornica with particular emphasis on the stomach and style sac region. Both species were found to be generally sim- ilar to other style-bearing mesogastropods in that they have little or no development of glandular tissue in the esophageal region and a functional style is present in the stomach. The stomachs of both species are specialized to transport and digest a continuous supply of detritus by means of complex ridges, grooves, and ciliary currents. Cerithidea californica appears more highly specialized for feeding on fine, highly organic detrital material than B. zonalis due to slightly more complex stomach morpho- logy. A possible correlation is postulated between the length of the crystalline style, relative to shell height, and the percentage of organic matter in the detritus ingested. ' Present address: Marine Environmental Center, Poulsbo, Wash- ington 98370 METHODS ann MATERIALS Specimens of Batillaria zonalis, ranging in size from 25 to 46mm, were collected along the shores of Tomales Bay (Figure 1, B.z.), while those of Cerithidea californica (Figure 1, C.c.), ranging in length from 25 to 32 mm, were collected in Drakes Estero, California. All the col- lecting stations were sampled from 7 to 10 times between March, 1966 and July, 1967. Specimens used for histological examination were re- moved from their shells and relaxed in 1% propylene phenoxytol in sea water before being killed and fixed in Bouin’s fixative. Paraffin sections, 10 and 12. thick, were stained with Alcian Blue, Mayer’s Haemalum, and counterstained with Eosin, using standard techniques found in Humason, 1962. Both living and preserved specimens were dissected. Living specimens were dissected immediately after col- lection, others after being starved for 3 to 4 weeks in the laboratory. Ciliary currents were determined with the aid of carmine and graphite particles suspended in sea water. Sediment samples from each collecting station were taken, dried and weighed. They were then resuspended in water and analyzed by wet sieving, using 5 sieves rang- ing from 1 mm to 0.065 mm mesh. The 5 fractions were then dried and weighed separately to obtain the particle size distribution of the substratum. All laboratory work was performed at the Pacific Marine Station, Dillon Beach, California. Page 376 HABITAT Batillaria zonalis is native to Japan and according to BarreTT (1963) may have been introduced to Tomales Bay as early as 1928 when the first experimental sets of Crassostrea gigas (Thunberg, 1793) were planted in the bay. However, the first observation of this species along the coast of California was reported in 1930 (Bonnor, 1935a). Crassostrea gigas was also introduced to Drakes Estero and Bodega Bay in 1932 (Bonnot, 1935b), but no specimens of B. zonalis were observed at either locality. Keen (1963) stated that the range of Cerithidea cali- fornica extends from Lower California northward to Bo- ee Pacific rg Marine E:.. Station Location of Tomales Bay in California Pacific Ocean Tomales Bay B.z.-2 Drakes Estero Figure 1 Map of Tomales Bay and Drakes Estero showing collecting stations: B.z. - Batillaria zonalis; 1 - Walker Creek Delta; 2- Willow Point; C.c. - Cerithidea californica; 1 - Schooner Bay; 2 - Johnson Oyster Company THE VELIGER Vol. 14; No. 4 linas, California. In this study, C. californica was collected further to the north in Drakes Estero, California. Mac- DONALD (1969) observed C. californica in Tomales Bay, but did not collect any. Both Batillaria zonalis and Cerithidea californica in- habit intertidal brackish mudflats and marshes. Batillaria zonalis was collected on the Walker Creek Delta (Figure 1, B.z.-1) and next to Willow Point at the head of Tomales Bay (Figure 1, B.z.- 2). At both localities the animals experienced wide fluctuations in temperature and salinity. On the Walker Creek Delta animals were found in pools of 2 to 5cm depths, in tidal channels, and on detritus-covered rocks and gravel. Occasionally the sub- stratum was dry where the animals were found. A sedi- ment analysis of the Delta surface mud showed 50% of the particles were between 0.065 and 0.25 mm in dia- meter and 50% were less than 0.065 mm in diameter. Less than 50% of the surface sediment was organic in nature. During cold weather the snails were found 1 to 2 cm beneath the surface. The length of B. zonalis rarely exceeded 25 mm at this station. Young snails with a length of 2 mm were first noted in May. The Willow Point collecting area was an abandoned man-made ditch which was about 5 to 7m wide and at least 0.5m deep. The ditch water was stagnant except for slight tidal exchange and the sediment was similar to that on the Walker Creek Delta. In contrast to the speci- mens collected at the Walker Creek Delta, the animals in this area were generally over 40 mm long, with a maxi- mum length of 46 mm noted. Cerithidea californica was collected at the north end of Schooner Bay in Drakes Estero (Figure 1, C.c.-1) ina marsh area and in small man-made pools next to the Johnson Oyster Company (Figure 1, C.c.- 2). Both lo- calities experienced fluctuations in temperature and salin- ity. At the Schooner Bay locality the animals were found along tidal channels which were 2 to 4cm deep, and in the marsh. Some areas of the channels were quite densely populated by the snails. Snails were never found on a dry substratum. A sediment analysis of the surface mud showed 5% of the particles were between 0.065 and 0.25 mm in diameter, and 95% were smaller than 0.065 mm. More than 80% of the surface sediment was organic in nature. During cold weather the animals were found just beneath the surface. The length of C. californica rarely exceeded 25 mm here or at the second locality. Developing larvae still within their protective egg cases were collected in June. At the Johnson Oyster Company Cerithidea californica was collected from unused man-made algae culture pools. The pools were dug into the marsh just above mean high tide so there was little direct exchange with the estero Vol. 14; No. 4 water. The pools were 3 to 4 m in diameter and had 5 to 10 cm deep water in them. The pools were carpeted with living and dead snails and the sediment was similar to that found at Schooner Bay. In no instance was either Batillaria zonalis or Cerithidea californica found coexisting in the localities sampled. Macponatp (1969) stated that although C. californica was present in Tomales Bay, it was not found in the samples where B. zonalis was collected. MORPHOLOGY The alimentary tract of Batillaria zonalis (Figure 2a) and of Cerithidea californica (Figure 2b) can be conveniently divided into 5 regions: (1) the buccal complex including radula and mucous glands; (2) the esophagus; (3) the stomach and style sac; (4) the digestive diverticula; and (5) the intestine. Figure 2 A. Diagram of the alimentary tract of Batillaria zonalis. B. Diagram of the alimentary tract of Cerithidea californica. The boundaries of the major regions of the alimentary tract are marked with solid lines. be — buccal cavity; dd — digestive diverticula; es — esophagus; in — intestine; mg — mucous glands; mo — mouth; rd — radula; ss — style sac; st — stomach; vdd — ventral duct of the digestive diverticula Buccal Complex: In Batillaria zonalis (Figure 3) the mouth (mo) opens into the buccal cavity (bc), the anterior limit being the THE VELIGER Page 377 pair of horny jaws (hj) on the anterior dorsal surface and the posterior limit being the point at which the radula sac (rs) is separated from the lumen of the gut (GRAHAM, 1939). Posterior to the jaws, the dorsal surface of the buccal lining, consisting mainly of columnar epithelium, becomes folded longitudinally (Figure 4, lf). The pair of dorsal grooves (dg) created by the dorsal longitudinal folds is heavily ciliated and conspicuous mucous cells are cross-section in Figure 4 Figure 3 Diagrammatic longitudinal section of the buccal region of Batillaria zonalis showing the inside of the buccal cavity and a portion of the inside of the esophagus. be — buccal cavity; dfg — dorsal food groove; es — esophagus; hj — horny jaws; lf — lateral folds; mg — mucous glands; mo — mouth; nr — nerve ring; od — odontophore; omg — opening of the duct from the mucous glands; rd — radula; rs — radula sac present in the lining of the grooves. The dorsal folds ex- tend beyond the posterior limit of the buccal cavity forming the beginning of a dorsal food groove. The lateral lining of the buccal cavity is smooth anteriorly and becomes folded posteriorly. The ciliated epithelial layer thickens posteriorly. The floor of the buccal cavity is covered by a thick cuticle with the exception of the ex- treme edges of the cavity where there are two small cili- ated pockets (cp) of unknown function. The entire buc- cal mass is surrounded by a thick layer of complex mus- culature. The radula (Figure 3, rd) is produced in the radular sac (rs) which opens ventrally into the posterior end of the buccal cavity. The number and type of teeth in each row of the radula is taeniglossan with one central tooth, one pair of lateral teeth, and two pairs of marginal teeth (FRETTER & GRAHAM, 1962). The radula extends anteri- orly out of the radular sac and is held against the floor of the buccal cavity by a radular membrane. The radula is Page 378 rd dg Figure 4 Diagram of a cross section through the middle of the buccal mass of Batillaria zonalis. cp — ciliated pockets; dg — dorsal grooves; les — lumen of the esophagus; If — longitudinal fold; od — odontophore; rd — radula supported by the cuticular lining of the buccal cavity and a pair of odontophores (od). In 8 specimens of Batillaria zonalis the shell length ranged from 28 to 45 mm and the radula length ranged from 2.5 to 3 mm and never exceeded twice the length of the buccal cavity. The average ratio of radula length to shell length was 0.11, which is lower than the lowest ratio reported by FRETTER & GRAHAM (1962) of 0.30 for Nucella lapillus (Linnaeus, 1758). Fretter and Graham indicated that radula length, as measured by the above ratio, ap- pears related to the substratum type. The radula is long where the substratum is coarse, causing heavy wear, and short where the substratum is soft. Dorsal to the opening of the radula sac and lateral to the dorsal ciliated grooves, a pair of ducts from the pair of buccal mucous glands (mg) open into the buccal cavity. Each of the buccal mucous glands lying along the dorsal surface of the esophagus (es) is composed of 3 to 4 small convoluted tubules. THE VELIGER Vol. 14; No. 4 The morphology and histology of the buccal complex of Cerithidea californica, as described by Bricut (1958) is similar to that of Batillaria zonalis. In 5 specimens of Cerithidea californica the shell length ranged from 28 to 30 mm and the radula length ranged from 2.5 to 3mm. The average ratio of radula length to shell length was a low 0.09. A relationship between short radula length and soft substratum seems evident in this species also. The paired buccal mucous glands composed of 3 to 4 small tubules are very similar to those in Batzl- laria zonalis. Other mesogastropods with similar buccal complex morphology are Bithynia tentaculata and Pomatias ele- gans, family Hydrobiidae, and Melanopsis praemorsa and Melania zenganus, family Melaniidae (GraHam, 1939). All possess the beginning of a dorsal food groove as found in Batillaria zonalis. Esophagus: The esophagus of Batillaria zonalis (Figure 3, es) is a tube which begins at the opening of the radula sac and extends to the stomach. As in other style-bearing gastro- pods, a dorsal food groove (dfg) is formed by 2 lateral folds (lf) which are continuations of the lateral folds in the dorsal wall of the buccal cavity. Posterior to the nerve ring (nr) the lateral folds twist to the left and the groove becomes ventrally located due to torsion. The lateral folds end at a point midway between the radula sac opening and the stomach. The epithelial lining of the dorsal food groove contains conspicuous mucous cells and is surrounded by a layer of muscle. The ventral esophageal lining is nonciliated and surrounded by a thin muscle layer. Anteriorly, the ventral lining is partially composed of large columnar cells un- like those lining the dorsal food groove. These cells, which appear glandular in nature, form small longitudinal ridges on the ventral wall and on the ventral side of the lateral folds in the esophagus. Posteriorly, the large colum- nar cells are replaced by typical columnar epithelial cells. The function of the large columnar cells is unknown. GraHam (1939) describes similar specialized cells of unknown function occurring in the ventral esophagus of Rissoa parva, Hydrobia sp., and Turritella communis, all style-bearing mesogastropods. The posterior esophagus of Batillaria zonalis is thin-walled, ciliated, and folded longi- tudinally just before entering the stomach. In Cerithidea californica the esophagus has been divid- ed into 3 regions by Bricut (1958); a pre-esophagus, a mid-esophagus with a large expanded region, called a “crop,” and a post-esophagus. These divisions are based on differences in gross morphology and histology only. GraHam (1939) stated that the esophagus of style-bear- ing gastropods performs the single function of food trans- Vol. 14; No. 4 port, and since this was also found to be the case in Cerithidea californica, divisions will not be stressed in this functional approach. In contrast to Batillaria zonalis, the esophageal food groove of Cerithidea californica ends after becoming vent- rally located as the whole esophageal lining becomes longi- tudinally folded. This folded area may be a vestige or a suppression of the glandular pouches of non-style-bearing gastropods (GraHam, 1939). The wall of the esophagus becomes spirally ridged just before entering the stomach, unlike the longitudinal folds present in B. zonalis. Through- out the esophageal lining in C. californica there are con- spicuous mucous cells. No large columnar cells were seen as were observed in B. zonalis. Stomach and Style Sac: In Batillaria zonalis the stomach (Figure 5) is the largest organ in the body whorl. The stomach, when opened by a dorsal longitudinal slit, is sac-like with the esophagus entering mid-ventrally (eso), and the intestine opening topographically anteriorly (in). Adjacent posteriorly and topographically to the right of the esophageal opening is the opening to the duct of the digestive diverticula (odd). The adjacent position of these openings is common to many style-bearing mesogastropods such as Mysorella costigera (SrsHatya, 1930), Hydrobia sp. and Bythynia tentaculata (GRAHAM, 1939). Mid-ventrally, to the right of both openings is a large muscular stomach ridge (lr) extending almost the full length of the stomach proper. The posterior end of the large ridge becomes smaller and thinner (sr), curving to the left and extending anteriorly to the opening to the duct of the digestive diverticula. The lateral groove formed by this stomach ridge channels food material from the esophagus toward the gastric shield. To the right of the anterior half of the stomach ridge lies the gastric shield (gs), a smooth, cuticularized area of the stomach lining. The shield provides a firm sur- face against which the style rotates. The dorsal wall of the stomach (sa) has many small, closely set ciliated ridges which begin on the right side and extend to the left toward the opening of the intestine. These ridges func- tion as a sorting area for food particles. The lining of the stomach is composed of columnar epithelium which is ciliated except for the area of the gastric shield and the ventral stomach wall between the gastric shield and the opening to the style sac. Beneath the epithelial lining is a thin, but distinct layer of muscle which plays an important role in moving food through the stomach and the digestive diverticula. The presence of a muscle layer in the stomach wall is similar to what SesHatya (1930) found in Mysorella costigera, but is in contrast to Struthiolaria papulosa which lacks any stom- ach musculature (Morton, 1951). THE VELIGER Page 379 Figure 5 Diagram of the stomach of Batillaria zonalis. The dorsal wall is cut open longitudinally and laid back to the right and left. The arrows represent direction of ciliary beat. dt — dorsal typhlosole; eso — esophageal opening; gs — gastric shield; in — intestine; ing — intestinal groove; int — intestinal typhlosole; Ir — large ridge; odd — opening of the digestive di- verticula; sa — sorting area on the dorsal wall; sr — small mdge; ss — style sac; vt — ventral typhlosole The anterior extension of the stomach proper (Figures 5, 6) contains the ventral (vt) and dorsal typhlosoles (dt), intestinal groove (ing), and the style sac (ss). The vent- ral typhlosole begins as a muscular bulge at the anterior edge of the stomach proper and narrows as it extends posteriorly to the end of the style sac. This is in contrast to most style-bearing mesogastropods which have a promi- Page 380 Figure 6 A cross section of the style sac and intestinal groove in Batillaria zonalis c — ciliary lining of the style sac; dt — dorsal typhlosole; ing — intestinal groove; s — style; se — style sac epithelium; sse — style secreting epithelium; vt — ventral typlosole nent ventral typhlosole which begins near the esophageal opening (GraHam, 1939). At the posterior end of the style sac the ventral typhlosole continues into the intes- tine (int). The dorsal typhlosole extends from the stom- ach proper and terminates at the posterior end of the style sac. The two typhlosoles come into contact with each other and functionally block communication between the style sac on the right side and the intestinal groove on the left side (Figure 6). Only at the anterior end of the style sac is there a sufficient opening for material to move between the style sac and the intestinal groove. The style sac is lined with ciliated cuboidal epithelium (Figure 6, se) except along the sides of the typhlosoles where the surface is composed of tall ciliated columnar epithelium (se) and style-secreting epithelium (sse). The intestinal groove (ing) is lined with ciliated columnar epithelium. The style sac contains the style (s), which is a tapered hyaline rod. In cross-section the style is a spiral coil of material usually consisting of 3 or 4 layers with the outer layer being thickest. The small posterior end of the style sometimes contains a few food particles from the intes- tinal groove which are bound into the style material. The style is spongy and dissolves rapidly in sea water or al- cohol soon after it is removed from the animal. In 11 spe- cimens the length of the style ranged from 4 to 6mm. THE VELIGER Vol. 14; No. 4 The ratio of style length to shell height was 0.13. The stomach of Cerithidea californica has been de- scribed and figured in general terms by Bricut (1958). Bright described the esophageal opening as occurring at the anterior end of the stomach and so figured it. Obser- vations made during this study on 50 specimens, both living and preserved, indicate that the esophagus enters midventrally rather than anteriorly (Figure 2, es; Figure 1, (0) Within the stomach of Cerithidea californica (Figure 7) there is a large midventral stomach ridge (Ir) which originates to the right of the opening of the duct of the Figure 7 Diagram of the stomach of Cerithidea californica. The dorsal wall is cut open longitudinally and laid back to the right and left. The arrows represent direction of ciliary beat. eso — esophageal opening; gs — gastric shield; in — intestine; ino — intestinal opening; Ir — large ridge; odd — opening to the digestive diverticula; rg — recycling groove; sa — sorting area on dorsal wall; sr, — small ridge -1; sr. — small ridge -2; vg — ventral groove in style sac; vt — ventral typhlosole ss — style sac; Vol. 14; No. 4 digestive diverticula (odd) and extends posteriorly, end- ing near the base of the stomach. This is in contrast to the large stomach ridge in Batillaria zonalis which curves anteriorly after nearing the base of the stomach. In addition to the midventral stomach ridge there are two smaller ridges (sr: and sr) in Cerithidea californica. The anterior portion of the first small ridge (sr:) forms a V with the apex pointed toward the intestinal opening and the angle of the V abutting the esophageal opening. This ridge prevents food entering from the esophagus (eso) from being carried by ciliary currents directly into WEEE Figure 8 Cross section of the style sac in Cerithidea californica. c — ciliary lining of style sac; dse — dorsal style secreting epithe- thelium; s — style; se — style sac epithelium; vg — ventral groove; vse — ventral style secreting epithelium the intestine. The second small ridge (sr.) extends from a point between the esophageal opening and the opening to the duct of the digestive diverticula posteriorly around the base of the large ridge and then anteriorly toward the gastric shield (gs), ending about the middle of the large ridge. SesHatva (1930) described a single long V- shaped ridge in Mysorella costigera which functions in the same manner as the two small ridges in C. californica. The stomach lining in Cerithidea californica is com- posed of columnar epithelium which is ciliated except THE VELIGER Page 381 for the areas of the gastric shield and the ventral wall between the gastric shield and the opening of the style sac. The anterior extension of the stomach in Cerithidea californica consists of a style sac (Figure 7, ss; Figure 8). The style sac opening is next to the opening of the intes- tine (ino) and communicates with it for a distance of less than 1 mm. Posteriorly the style sac and intestine are completely separated. There is a prominent longi- tudinal ventral groove (vg) in the style sac which was not described by Bricut (1958). The groove is bounded on both sides by several rows of tall, ciliated columnar epithelial cells (dse and vse) and mucous cells. These cells are similar to those found on the edge of the typhlosoles in the style sac of Batillaria zonalis and their function is also similar. There is a ventral typhlosole present in C. californica in the form of a muscular bulge (Figure 7, vt) between the openings of the style sac and the intestine, but it does not extend into the intestine. However, in the style sac the specialized cells along the right side of the ventral groove appear to be a remnant of the ventral typhlosole (Figure 8, vse). The dorsal typhlosole is not evident in the stomach of C. californica; however, it appears that the specialized cells along the left side of the ventral groove in the style sac may be remnants of the dorsal typhlosole (dse). The cells lining the remainder of the style sac are heavily ciliated cuboidal epithelium (se), just as in Batil- laria zonalis. The arrangement of a separate style sac containing a ventral groove is not unique. GRAHAM (1939) described a similar situation in Rissoa parva, family Rissoacea. SesHATYA (1929a) described a style sac groove in the species Paludomus tranchaurica; in the genera Melanoides, Mysorella and Amnicola (SrsuHarya, 1929b) ; and in the species Potamides cingulatus, family Cerithiidae (SESHAI- VAR LOS2Ne The style is crystalline and proteinaceous in nature (BricHT, 1958). In 5 specimens the length of the style ranged from 14 to 16mm and the height of the shell ranged from 28 to 30mm. The ratio of style length to shell height was 0.51. The style normally extends the length of the style sac and into the stomach, where it dissolves as it rotates against the gastric shield. Of 25 live dissections, 2 revealed unusual style positions. In one case, the style extended beyond the gastric shield to the base of the stomach; in the other case, the style did not touch the gastric shield at all. The style entered the stomach to the left of the large stomach ridge and extended over the openings to the ducts of the digestive diverticula terminating at the posterior end of the large ridge. The crystalline style of Cerithidea californica is firm, but flexible and does not dissolve in sea water, 70% iso- propyl alcohol or Bouin’s fixative. Page 382 In the stomach of Cerithidea californica the intestinal opening (Figure 7, ino) is to the left of the style sac opening. Several ciliated tracts lead to the intestinal open- ing along the stomach walls as in Batillaria zonalis. Digestive Diverticula: The opening to the duct of the digestive diverticula in Batillaria zonalis (Figure 5, odd) leads into a single main duct (Figure 2, vdd), which extends to the tip of the vis- ceral hump along the ventral side. The main duct is lined with non-ciliated columnar epithelium. From the main duct there are numerous smaller ducts leading into the digestive diverticula tissue. These secondary ducts split once or twice and lead to sinuses lined by 2 types of cells which are very similar to those described to be digestive and excretory in nature in Bithynia tentaculata (FRetTer & Grawam, 1962) and in Struthiolaria papu- losa (Morton, 1951). The excretory cells are character- ized by the presence of what appear to be excretory spherules. The digestive diverticula in Cerithidea californica are similar to those of Batillaria zonalis in having a single ventral main duct (Figure 2b, vdd), lined with ciliated columnar epithelium as described by Bricut (1958). Also, the digestive diverticula of C. californica have a branch- ing duct system leading to the sinuses lined with the same types of cells as found in B. zonalis. The presence of a single ventral main duct in the digestive diverticula is reported to be common by E. H. Smith (personal communication) although FRETTER & GraHAM (1962) commented that in many prosobranchs a pair of ducts is frequently found. Intestine: The intestinal groove in Batillaria zonalis (Figure 5, ing) leads directly into the intestine. The intestine makes a loop and then extends anteriorly along the right side of the mantle cavity and ends just inside the mantle edge at the anus. The first third of the intestine is character- ized by the presence of a ventral intestinal typhlosole (int), which is an anterior extension of the ventral typhlo- sole of the stomach and style sac regions. The middle third of the intestine lacks the typhlosole and is the region where fecal pellets are formed. The last third of the in- testine has folded walls capable of expanding to hold several fecal pellets at one time. The intestine is lined with ciliated columnar epithelium and scattered mucous cells. In the stomach of Cerithidea californica, the intestinal opening (Figure 7, ino) is to the left of the opening of the style sac. There is a longitudinal ventral typhlosole present in the first section of the intestine, as in Batillaria zonalis, but it does not connect with the ventral typhlo- THE VELIGER Vol. 14; No. 4 sole in the stomach. Present with the typhlosole are 5 longitudinal ridges. The fold and ridges end after the first loop of the intestine. The next region is characterized by its resemblance to a triangle when seen in cross section due to 3 thickenings in the intestinal wall. This is the pellet-molding region. Morton (1951) described a sim- ilar triangular region in Struthiolaria papulosa, which has the same function. The posterior portion of the in- testine is similar to that in B. zonalis. The intestine ends just inside the right edge of the mantle cavity at the anus. The entire intestine is lined with ciliated columnar epi- thelium as Bricut (1958) described. FUNCTIONAL MORPHOLOGY Buccal Complex: Batillaria zonalis feeds by scraping a fluid mixture of mud and detritus into its mouth with a radula. The radula rasps continually while the animal is on a moist sub- stratum. Animals were not observed feeding while on a dry substratum. The radula draws the food material under and against a chitinous jaw within the mouth which causes the aggregated food particles to be broken into smaller pieces. Posterior to the jaw, the food particles are picked up by ciliary currents in the dorsal lateral grooves. As the particles proceed toward the esophagus, mucus is added from a pair of small buccal mucous glands. The dorsal lateral grooves become a single dorsal food groove in the esophagus. The radula in Cerithidea californica functions in the same manner as the radula in Batillaria zonalis. However, the substratum on which C. californica feeds is finer and more uniform than that of B. zonalis, and it was always moist, resulting in a more continuous feeding habit than that of B. zonalis. Food is carried past the jaw, mixed with mucus from the small buccal mucous glands and moved posteriorly by ciliary currents to the dorsal food groove of the esophagus. Both, Batillaria zonalis and Cerithidea californica, have short radulae which appear to be correlated to the soft substratum on which the animals feed (FRETTER & Gra- HAM, 1962). In addition, both species possess only one pair of mucous secreting glands in the buccal complex. These glands are small, apparently because the food mix- ture is quite fluid and therefore mucus is only needed to bind the food into a food string and not needed to lubri- cate the radula. The probability that the mucus contains digestive enzymes is small. GRAHAM (1939) stated that since proteolitic enzymes from the buccal mucous glands will interfere with the functioning of a crystalline style, the function of the glands is accordingly modified in Vol. 14; No. 4 THE VELIGER Page 383 style-bearing prosobranchs. In addition, FreTTER & Gra- HAM (1962) reported that few prosobranchs secrete digestive enzymes in the mucus from buccal mucous glands. Ciliary currents constitute the major means for trans- porting food material in the alimentary system of both species and the dorsal lateral grooves in the buccal com- plex are the beginning of this ciliary transport system. The currents created by the ciliary beat in the grooves efficiently channel the food material away from the radula and toward the esophagus, thereby preventing the buccal cavity from becoming clogged. The functional morphology of the buccal complex of Mysorella costigera (SEsHatya, 1930) and Struthiolaria papulosa (Morton, 1951) is quite similar to that of Batillaria zonalis and Cerithidea californica. Mysorella costigera, a freshwater hydrobid with a crystalline style, feeds on fine moist detrital material in India and S. papu- losa, a marine style-bearing ciliary feeder in New Zea- land, also ingests fine detrital material. Esophagus: In Batillaria zonalis, food enters the dorsal food groove of the esophagus from the two dorsal lateral grooves of the buccal cavity and is carried posteriorly by ciliary currents. Almost no food is found in the anterior non-ciliated vent- ral portion of the esophagus. Although glandular-like tissue is present in the ventral esophagus, its function is unknown. Throughout the length of the esophagus, mucus is added to the food mixture, creating a food string. Ciliary currents continue to transport the food string pos- teriorly through the esophagus to the stomach. In Certthidea californica, as in Batillaria zonalis, food in the esophagus is carried by ciliary currents almost ex- clusively in a dorsal food groove. Ventrally there is no glandular tissue, as was found in the ventral esophagus of B. zonalis. Unlike B. zonalis, the dorsal food groove of C. californica blends into a multifolded expanded region just posterior to the area of torsion. Glandular tissue is absent; however, mucus is added to the food in the ex- panded region. Ciliary currents continue to carry the food string posteriorly to the stomach. These findings agree specifically with those of GRAHAM (1939) concerning the modification of esophageal glandu- lar areas in style-bearing gastropods. Graham reported that the glandular areas were either suppressed (which is the case in Batillaria zonalis) or replaced by ciliated and mucous Cells with the walls retaining their expanded and folded nature (which is the case in Cerithidea californica). Graham concluded that a style and a series of glandular esophageal structures are alternative mechanisms, mutu- ally inconsistent, for helping in the digestion of food. Stomach and Style Sac: In Batillaria zonalis, food is carried into the stomach mid- ventrally from the esophagus. Once in the stomach, the movements of food are affected by ciliary beat (Figure 5), stomach morphology, rotation of the style, muscular activ- ity of the stomach walls and internal fluid pressures. New techniques, such as the use of X-rays, need to be developed before the effect of muscular activity of the stomach wall and the internal fluid pressures can be studied, since it is impossible to study their functioning once the stomach has been dissected. Ciliary currents on the ventral surface of the stomach carry the food posteriorly to the base of the stomach and then anteriorly to the gastric shield and rotating style. The stomach ridge (sr and Ir) keeps the food string in the groove leading to the gastric shield. The style, which is rotating clockwise. (seen from a posterior view) against the gastric shield is slowly dis- solving and apparently releasing digestive enzymes, one of which is probably amylase (YoncE, 1932). Tall, slen- der glandular cells along the edge of the typhlosole (Fig- ure 6, sse) within the style sac produce the style material which then is added to the entire length of the style sacas it rotates. The style is rotated by a strong ciliary current within the style sac and at the same time pushed against the gastric shield by the constant addition of style material to its tapered surface. The style material dissolves because the hydrogen ion concentration of the stomach is higher than that of the style sac, causing a change in viscosity of the style material (YoncE, 1932). The food material is caught in the dissolving end of the style and moved clock- wise with it. The enzymes from the style begin digestion of the food by breaking down the larger usable particles. The food particles are swept away from the style by ciliary currents on the dorsal wall which flow parallel to, but in opposite direction of, the style’s rotation. The dorsal wall of the stomach (Figure 5, sa) is composed of numer- ous closely set ridges which serve as a sorting area for the food material. Larger particles, which would include most of the unusable material, break loose from the mucus and food mixture and are swept into grooves of the sort- ing area and then transported directly to the intestinal groove (ing) and then to the intestine (in) by ciliary currents. Morton (1953) has suggested that the slit between the style sac and the intestinal groove is functionally important in providing for the possible retrieval of un- digested food material leaving the stomach. In Batillaria zonalis the position of the typhlosoles and the ciliary cur- rent on the surface of the ventral typhlosole functionally block communication between the intestine and the style Page 384 sac. There appears to be no retrieval mechanism in the stomach and style sac region of B. zonalis. The smaller particles remain in the lumen of the stomach where the enzymes from the style continue to act on them. Multidirectional ciliary currents on the surface of the large ridge keep the stomach contents in motion. Periodically, muscular contractions of the stomach force food material into the digestive diverticula (odd), where digestion and absorption take place. As the stomach wall relaxes, the food mixture is drawn out of the digestive diverticula and picked up by ciliary currents on the floor of the stomach and carried anteriorly to the intestinal groove. In Cerithidea californica food material enters the stom- ach mid-ventrally (Figure 7). It is prevented from being carried directly into the intestinal opening by a small ridge (sri). This feature is absent in Batillaria zonalis. The material is carried toward the gastric shield and rotating style by ciliary currents on the ventral wall of the stomach groove. The groove is bounded medially by 2 stomach ridges (sr2 and Ir), which is in contrast to the single stomach ridge in B. zonalis. The style in Cerithidea californica rotates clockwise, slowly dissolving and releasing digestive enzymes as in Batillaria zonalis. Tall, slender glandular cells found along the ventral groove of the style sac of C. californica (Fig- ure 8, vse and dse) secrete style material throughout the style sac, but primarily at the distal end. These glandular cells along the ventral groove are homologous to the gland- ular cells on the typhlosoles of the style sac in B. zonalis. This homology is supported by Morton (1951), who has described the secretion of the style in Struthiolaria papu- losa as coming from a narrow strip of tall cells along the typhlosole. The drawings of Kusomura (1957) diagram- ming cross sections of style sacs of the tectibranch Philine japonica, and the mesogastropod Oncomelania nosophora, show an area on the typhlosole of small, slender cells similar to those in both B. zonalis and C. californica. SesHarya (1930) found tall, slender cells along the typh- losole of the freshwater, style-bearing gastropod, Mysor- ella costigera, but did not discuss their function. Also, FRETTER & GRAHAM (1962) stated that most of the style substance is derived from the gland cells on the typhlosole. Food material is swept away from the rotating style by currents on the dorsal wall of the stomach (Figure 7, sa). The dorsal wall acts as a sorting area and larger particles are moved into the grooves of the sorting area and are transported by ciliary currents into the opening to the intestine. The smaller particles remain in the lumen of the stomach where the digestive action continues and where ciliary currents and muscular contractions can move them into the duct to the digestive diverticula. In THE VELIGER Vol. 14; No. 4 contrast to Batillaria zonalis, in the stomach of Cerithidea californica a ciliated ventral groove (vg) is present be- tween the two ventral ridges (Ir and sr:) which allows some of the food particles to re-enter the channel leading to the gastric shield and hence be re-sorted and digested further. Material leaving the digestive diverticula is carried by ciliary currents toward the intestine channeled by a small ridge (sr2) which prevents mixing of the material entering and leaving the stomach. The basic functional morphology of the stomach and style regions of both, Batillaria zonalis and Cerithidea californica, are similar to most style-bearing mesogastro- pods. However, as YoNcE (1932), Granam (1939), and Morton (1953) have stated, the stomach in style-bearers is the region most highly specialized for sorting and di- gesting a continuous stream of fine detrital material. In light of the apparent differences in substratum, and hence in ingested food in the species in this study, it is relevant to examine the detailed functional morphology of the stomach regions for possible correlations with food type. As noted above, the food material ingested by Cerithi- dea californica is very fine and is composed of over 80% organic material. The ridges (sr: and sr2) present in the stomach of C’. californica are specialized structures which channel food material toward the areas of sorting and digestion. The first ridge (sr:) prevents the incoming food material from becoming immediately mixed with the out- going material and thus lost for digestive purposes. The second ridge (sr2) serves to channel food material which has already passed over the dorsal sorting area back into the groove leading to the gastric shield and style where additional digestive material may be added to the mixture. In contrast, in Batillaria zonalis, the food material in- gested is poorly sorted and is low in organic content and the stomach morphology is less complex. Food material is moved through the stomach as a vaguely defined mass with few channeling ridges and with no recycling currents. The food material does not warrant specialized morpho- logical features to prevent premature loss of food material nor does it need recycling to add further style enzymes for complete digestion. This study suggests a relationship between style length and the compositon of the ingested food. A general cor- relation between food type and functional morphology is well established. MackinTosH (1925) postulated that the presence of a style in gastropods may be correlated with the ingestion of diatoms and similar micro-organisms. Yonce (1930) stated that the presence of a style in gastro- pods is correlated with either a ciliary or a rasping mode of feeding and formulated the rule that the presence of a | style means the animal is a specialized herbivore. YONGE © Vol. 14; No. 4 THE VELIGER Page 385 (1932) examined this correlation further and noted that while the style is restricted to herbivorous gastropods, it is not true that all herbivorous gastropods possess a style. Only those which supply finely divided food continuously to the stomach possess a style. GRAHAM (1939) stated that the style developed in those animals which feed con- tinually on unicellular or small multicellular algae. Morton (1953) stated that the crystalline style sac in the Lamellibranchia remains generally longer and more specialized than in the Gastropoda. In the Lamellibran- chia the gills sort the food material and reject the larger and heavier particles in “pseudofeces” before they enter the mouth. In comparison, Cerithidea californica feeds on a substratum which is already quite well sorted and highly organic in composition and correspondingly it pos- sesses a relatively long style. In contrast, Batillaria zonalis with a short style, feeds on a substratum which is not as well sorted and which has a low organic content. An enzyme supply sufficient to fully digest the available food would be advantageous for a slow, continuously feed- ing mollusk. It may be possible that an increase in avail- able enzymes is brought about in those Lamellibranchia and Gastropoda which digest well sorted and _ highly organic food material through elongation of the style sac with a corresponding increase in style secreting tissue and style length. Assuming a fairly similar even rate of style production from species to species, the increase in style length would provide an increase in the supply of digestive enzymes. Digestive Diverticula: In Batillaria zonalis particles entering the digestive diver- ticula are well mixed with style mucus. This mixture is pumped down the main duct of the digestive diverticula (Figure 2a, vdd) by contractions of the stomach. No cili- ary currents were observed to aid food movement in the main duct. Following each contraction the stomach re- laxes and the material in the duct moves toward the stomach. These movements in the duct were observed only in intact specimens. The material in the secondary ducts moves in and out in an irregular manner which is inde- pendent of the movement in the main duct and indicates that the stomach contractions do not move material into the secondary ducts. Since there are no muscles in the digestive diverticula tissue, it appears that regulated cili- ary currents may be responsible for movement in the secondary ducts. In Cerithidea californica material is pumped in and out of the main duct of the digestive diverticula (Figure 2b, vdd), as in Batillaria zonalis, by stomach contractions. Also, material appears to enter and leave the secondary ducts by ciliary means as in B. zonalis. In C. californica, however, there is a definite rhythm and timing to the movement within the secondary ducts which is independ- ent of the movement of the main duct. In both, Batillaria zonalis and Cerithidea californica, the movement of material through the branching system of the digestive diverticula first by muscular contractions and then by ciliary beat, functions to steadily bring the food material into contact with the digestive epithelium where intra-cellular digestion apparently takes place. The excretory spherules present in the epithelium, described previously, appear to be carried out of the tubules into the main duct of the digestive diverticula and from there into the ciliary currents on the ventral surface of the stomach which enter the intestine. The functioning of the digestive diverticula in both B. zonalis and C. californica appears very similar to that described by Morton (1951) in Struthiolaria papulosa. Intestine: In Batillaria zonalis, after leaving the stomach, undigested and undigestible material enters the intestine where it is carried posteriorly by ciliary currents. The intestine ap- pears to function solely to compact the food material into fecal pellets. Hyman (1967) stated that the hydrogen ion concentration in the intestine is higher than it is in the stomach. This results in an increase in the viscosity of the intestinal mucus which serves to bind the fecal matter. The function of the ventral typhlosole in the anterior third of the intestine of B. zonalis is unclear. The mid-portion of the intestine molds the fecal matter into fecal pellets through the peristaltic action of the muscles lining the in- testine. In the posterior portion the final mucous coating is added to the fecal pellets and the expanded region just anterior to the anus allows room for the pellets to be stored briefly while the mucous coating hardens. The fecal pel- lets are expelled periodically by peristaltic action and cili- ary currents carry them away from the mouth along the right side of the foot and head. In Cerithidea californica the intestine also appears to function solely for compacting and transporting the fecal matter out of the body cavity. The viscous intestinal mucus binds the fecal matter as in Batillaria zonalis. The ventral typhlosole in C. californica appears to function somewhat as a channel for the fecal material since the majority of the fecal matter was observed massed along the left side of the typhlosole. In addition, the 5 ridges present in C. californica may be specialized mucous secreting areas since the ridge tissue appears glandular in nature. The fecal material is molded into pellets in the mid-intestine and the mucous coating hardens in the expanded posterior region as in B, zonalis. The pellets are expelled and car- Page 386 ried away from the mouth in the same manner as in B. zonalis. ACKNOWLEDGMENTS I wish to thank Dr. Edmund H. Smith for his invaluable advice and help during my research and the preparation of this paper. I also want to thank Dr. John Tucker, Dr. Gary Brusca and Dr. Michael Kaill for their help, and Dr. A. Myra Keen who verified the identification of the two species studied. Literature Cited BARRETT, ELINORE M. 1963. The California oyster industry. Calif. Dept. Fish & Game, Fish Bull. 123: 103 pp.; 32 text figs. Bonnot, PauL 1935a. A recent introduction of exotic species of molluscs in California waters from Japan. The Nautilus 49: 1 - 2 1935b. The California oyster industry. Calif. Fish & Game 21 (1): 65-80 BricHT, Dona.p B. 1958. Morphology of the common mudflat snail, Cerithidea californica. Bull. So. Calif: Acad. Sci. 57 (3): 127 - 139; plts. 37 - 41 1960. Morphology of the common mudflat snail, Cerithidea californica, II. Bull. So. Calif: Acad. Sci. 59 (1): 9-18; plts. 4-6 FRETTER, VERA, & ALASTAIR GRAHAM 1962. British prosobranch molluscs, their functional anatomy and ecology. London, Ray Soc. xvi+755 pp.; 316 figs. GraHAM, ALASTAIR 1939. On the structure of the alimentary canal of style- bearing prosobranchs. Proc. Zool. Soc. London (B) 109 (1): 75-112; 9 text figs. Hanna, G DA.ias 1966. Introduced mollusks of western North America. Occ. Pap. Calif. Acad. Sci. no. 48: 108 pp.; 85 figs.; 4 plts (16 February 1966) THE VELIGER Vol. 14; No. 4 Humason, GreTcHEN L. 1962, Animal tissue techniques. W. H. Freeman and Co., San Francisco, Calif. xv-+468 pp.; 27 text figs. Hyman, Lissy HENRIETTA 1967. Mollusca, I - vol.6 of The invertebrates. McGraw- Hill, New York, vii+792 pp.; 249 figs. Keen, A. Myra 1963. Marine molluscan genera of western North America: an illustrated key. Stanford Univ. Press; 1 - 126; illust. Kusomura, Kazuko 1957. | Some Japanese gastropods with the crystalline style. Sci. Reprt. Saitama Univ., Ser. B (Biol.) 2: 269 - 279; plt. 36; 7 text figs. MacponaLp, Keitu B. 1969. Molluscan faunas of Pacific coast salt marshes and tidal creeks. The Veliger 11 (4): 399-405; 1 text fig.; 3 tables (1 April 1969) Macxintosu, N. A. 1925. The crystalline style in gastropods. Micr. Sci. 69: 317 - 342; plts. 20, 21; 3 text figs. Morton, Joun Epwarp 1951. Ecology and digestive system of the Struthiolariidae. Quart. Journ. Micr. Sci. 92: 1 - 25; 25 text figs. 1953. The functions of the gastropod stomach. Proc. Linn. Soc. London 164: 240 - 246; 3 text figs. SesnalyA, R. V. 1929a. The stomach of Paludomus transhaurica (Gmelin). Rec. Indian Mus. 31: 7 - 12 1929b. ‘The style-sac of some freshwater gastropods. Rec. Indian Mus. 31: 101 - 105 Quart. Journ. 1930. Anatomy of Mysorella costigera Kiister. Rec. In- dian Mus. 32: 1 - 28; 27 text figs. 1932. The style sacs of some more gastropods. Rec. Indian Mus. 34: 171-175; 4 text figs. YonceE, CHartes MAurRICE 1930. The crystalline style of the mollusca and a carnivorous habit cannot normally coexist. Nature, 125: 444 - 445 1932. Notes on feeding and digestion in Pterocera and Ver- metus, with a discussion on the occurrence of the crystalline style in the Gastropoda. Sci. Reprt. Grt. Barr. Rf. Exped. [Brit. Mus. (Nat. Hist.)] 1 (10) : 259 - 281; 6 text figs.; 3 tables Vol. 14; No. 4 THE VELIGER Page 387 Competitive Co-Existence: Maintenance of Interacting Associations of the Sea Mussels Mytilus edulis and Mytilus californianus BY J. ROBIN HARGER' Department of Biological Sciences, University of California at Santa Barbara, California 93106' (8 Text figures) INTRODUCTION IN SPITE OF THE LARGE AMOUNT of practical and theo- retical work on interspecific competition which has been produced since Darwin’s Origin of Species (1859), few field experimental investigations of the process have been performed. The work of ConnELL (1961a, 1961b) pro- vides notable relief from this lamentable state of affairs. Most studies have demonstrated that the competitive ex- clusion principle as outlined by Harpin (1960) provides an appropriate model to account for the fact that one or the other of any pair of competing species eventually eliminates its opponent in a homogeneous laboratory uni- verse of limited extent. While it is true that the process involved may take considerable time [FRanxK (1952, 1957); Park (1948, 1954)], involving several generations of the animals concerned [see MitiEr (1969) for a discussion of this point], and perhaps extending over a longer time interval than most natural habitats would last in an un- altered state, nevertheless the outcome is always predict- able, even if prior identification of the victor is uncertain [NEYMAN et al. (1956) ]. Mathematical models of com- petition utilizing the concept of a persistent advantage accruing to one species with consequent disadvantage to the other [Gause (1934); Gause & Wirt (1935)] or stochastic versions of this process [BarTLETT (1960) ; Lesuiez (1962) ] indicate a similar outcome provided only that resource limitation is postulated. AyALa (1968, 1971) provides one of the few examples of a laboratory system wherein competitive exclusion does not take place (see later). * Present Address: Department of Zoology, University of British Columbia, Vancouver 8, British Columbia, Canada It is obvious that organisms overlap in their require- ments for both physical and biological resources, and the extent to which competitive interactions are realized in nature between sympatric species is endlessly debated. The principal argument advanced to substantiate absence of such competition is that differences allowing for separa- tion of species are sufficient to permit co-existence by enabling them to avoid competition for limited resources. Core (1960), in fact, criticizes the stress Harbin (1960) places on the competitive exclusion principle because it leads to such circularity in interpreting field results. DE Bacu (1966) admits to the existence of transient compe- titive displacement which may hold sway for undefined but definite periods following range extensions or the arti- ficial introduction of organisms into new habitats. The mechanism of competitive displacement is presumed to result in organisms spacing themselves apart from one another with respect to their demands for potentially limited resources, such that they fail to effectively com- pete with each other. De Bacu (op. cit.) goes to consider- able lengths to define “ecological homologues” as species having the same “ecological niche”; he also states that species having different ecological niches are able to co- exist indefinitely in the same habitat. Unfortunately, these ‘definitions are applied by pointing out that cases of co- existence pertain only to species which are not ecological homologues. Since all species differ in some respect to each other, this is of little help, particularly when it is indicated that “niche overlap” need only be partial in the sense that “niches do not have to be identical in all re- spects for competition and displacement to occur.” The problem of circularity exists throughout DE Bacw’s (op. cit.) review. Harper et al. (1961) postulate that continued cohabi- tation of competing species is possible only if species dif Page 388 fer in such a way that their populations become inde- pendently controlled, and that apparent cohabitation in nature presents a challenge (to the biologist) which can be met by showing: (a) that apparent cohabitation is spurious because there is really a previously undetected heterogeneity in the habitat, in space or time, so that the populations do not really cohabit; (b) the cohabita- tion is transient and does not represent a stable state; (c) the populations or species concerned do not have cont- rolling factors in common. Harper et al. (op. cit.) further state that it is clear from mathematical models (W1LL1aAM- son, 1957) that two non-interbreeding populations or species are unable to exist together in equilibrium if they hold a controlling factor in common. It is, however, likely that heterogeneity is always pres- ent in the habitat of organisms engaged in competitive interaction in nature. Since the effects of such hetero- geneity are difficult to evaluate in the absence of extensive experimental investigation, a claim which substitutes “he- terogeneity” for an understanding of processes involved is of little value. The statement concerning transience is also difficult to evaluate, since it involves setting undefined standards; namely, transient with respect to what? Most ecologists will agree that most population interactions are transient in nature. Thus, transience could relate to a geological time scale or one reflecting the life span of the organism or some lesser interval. WILLIAMSON (op. cit.) describes a “controlling factor” as one which acts more severely against the individuals of a population when the population increases and so tends to control the popula- tion size. Two species are in competition when they have a controlling factor in common, and conversely, if two species are in competition, they have a controlling factor in common. WILLIAMSON (op. cit.) concludes that two species, each with a constant birth rate and death rate caused only by a single controlling factor acting simply on both of them, cannot coexist. Obviously, this does not mean that the existence of a controlling factor acting on two species precludes co-existence. It is clear that Darwin (1859) regarded the operation of competitive interactions between organisms as an es- sential factor promoting evolution: “ as more indi- viduals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with indi- viduals of distinct species or with the physical conditions of life.” And later, “As the species of the same genus usually have, though by no means invariably, much simi- larity in habits and constitution, and always in structure, the struggle will generally be more severe between them, if they come into competition with each other, than be- tween the species of distinct genera.” THE VELIGER Vol. 14; No. 4 There is no doubt that competition occurs in natural communities. That exclusion of one species by another in laboratory experiments takes place is also a fact. It is, therefore, important to enquire into the conditions under which co-existence may be maintained, in spite of com- petitive interactions between species. What are the factors governing degree of overlap that may exist between spe- qies? An attempt to answer such questions underlies the development of this work. Several authors have envisaged situations wherein the co-existence of competing species [‘‘Ecological Homo- logues,” Dr Bacu (1966) ] would be possible. HutcHin- son (1957) suggests that co-existence might occur if the advantage of one species over the other is continually re- versed by habitat variations. Kromp (1961) considers this could occur only if habitat variations were dependent on the numerical ratio of the species involved. I have indicated (Harcer, 1970c) that in this system of inter- acting sea mussels such a possibility exists, in that the ef- fect of wave action on mussel populations varies according to the proportions of the two species constituting the clumps. PimeNnTEL et al. (1965) have proposed that struc- tural diversity may allow competitively superior geno- types to evolve in beleaguered populations in response to selection imposed by temporarily successful genotypes of numerically dominant species. NicHoLson (1954) ac- counts for co-existence in regions of species overlap by continual re-colonization from species-specific refuges. WitiiaMson (1957) claims two species may co-exist if they possess two or more “controlling factors” in common. In fact, WittiAMSON (of. cit.) considers it likely that survival of both competitors becomes more likely as more variables are considered. SKELLUM (1951) postulated a method whereby two species in competition may co-exist if one species, the loser in spots seeded by both, neverthe- less produces more seeds than the other species, and so it is better able to find new vacant spots. HuTcHINSON (1957) also points out co-existence may be expected when potential competitors occur at such low densities that competition is not involved. Sea mussels lend themselves admirably to experimental investigation of competition. In accordance with the sug- gestions proposed by Park (1962), “they are easily and safely handled, can be readily grown apart and in conjunc- tion with one another, and can be manipulated to grow in different environments.” An evaluation of some of the foregoing ideas was sought in a field investigation of fac- tors affecting interaction of Mytilus edulis Linnaeus, 1758 and M. californianus Conrad, 1837. The first step in this process was to determine whether both competition and co-existence were taking place in natural populations. Vol. 14; No. 4 THE VELIGER Page 389 Mytilus edulis and M. californianus are two species of sea mussel which occur in large numbers on the shores of Southern California. Mytilus edulis attains high popula- tion densities in quiet waters, such as those found in harbors, beneath marina floats, etc. Occurrence in this hab- itat has given rise to the name “bay mussel.” This species is, however, not confined tosuch situations and occurs in considerable numbers, together with M. californianus (the “open coast” mussel) intertidally on exposed pier pilings (Harcer, 1968), oil rig pilings (CARLISLE et al., 1964) and indeed along most of the exposed shore line of South- em California. Sruspincs (1954) reports a “world wide” distribution for MM. edulis, since it is present in both north- ern and southern hemispheres. Mytilus californianus is confined in distribution to the west coast of North America, where its range extends from the Aleutian Islands to Isla del Socorro, Mexico (Soot-Ryen, 1955). It occurs principally on exposed shorelines, but may extend into harbors, particularly if the water is generally free from silt and suspended particu- late matter. In Northern Washington, for instance, it oc- curs on the shores of San Juan Island, situated in Puget Sound, midway between the Strait of Juan de Fuca and the mainland, a comparatively protected region character- ized by clear water and swift currents. I have found Myt7- lus californianus growing under marina floats in Morro Bay (San Luis Obispo County, California), Santa Barbara Harbor, and in the Ventura Marina (Ventura County, California). As reported previously (Harcer, 1968), both species contribute to the formation of mussel clumps on pier pilings in Southern California. Representation of Mytilus edulis in such clumps may vary from a few small individ- uals to 50% or more by number. Generally speaking, mussel clumps in locations exposed to heavy wave action contain fewer and smaller individuals of M. edulis than those in more sheltered situations (Harcrr, 1970a, 1970c). In conditions of extreme exposure, such as found on the Monterey Peninsula (Monterey County, California), M. edulis was entirely absent. However, a surprisingly high representation of M. edulis (50% by number) occurred in clumps exposed to moderately heavy wave impact on a pier belonging to the Standard Oil Company at Cayucos Beach, San Luis Obispo County, California (Harcer, 1970a). Small individuals of Mytilus edulis also occur on the ex- posed outer coast of Vancouver Island, British Columbia, at Port Renfrew, indicating that overlap between the two species is not confined to Southern California. The inves- tigation reported here was initiated after I observed both M. edulis and M. californianus making up large clumps on pilings supporting Ellwood Pier (property of Signal Oil and Gas Company). This pier is located some 14 miles west of Santa Barbara on an open sandy shore. Constructed on steel girders, it extends approximately 4 mile into the sea, from the shallow surf zone to a depth of 40 feet. Mussels were confined in clumps of varying sizes (ranging from a few individuals to large masses over 17 feet in circumference). Maximum vertical extent was 7 to 9 feet (from 1.5 - 2 feet below the extreme high water spring tide mark to the low water mark — 0.0 chart datum). In all cases the animals were packed closely together (see Harcer, 1968 for a description of clump structure). A limited amount of substrate suitable for mussel coloni- zation is available in the intertidal region. Most subtidal surfaces are unsuitable because predation by sea stars (LANDENBERGER, 1967), crabs and fish results in the rapid removal of settling mussels (see also SEED, 1969). This would seem to indicate that space sometimes limits population densities of these animals. The effect of such limitation was particularly noticeable on the pier pilings, most of which were H-beams 9 inches on a side. A large mussel clump, 17 feet in circumference, vertical extent of 9 feet, was approximately 28 inches thick from the outside surface to the central piling support. At least 14 or more mussels are piled one on top of the other at this point: all are fastened to the central pillar. PHYSICAL CHARACTERISTICS oF THE MUSSELS As might be expected, the two species of mussels are dis- similar in their most easily measured characters. Shells of Mytilus californianus are almost always heavier than sim- ilar sized shells of Mf. edulis taken in the same place (p < 0.001, Harcer, 1967, table 4). An exception occurs when old individuals of Mf. edulis occur in exposed situa- tions together with young specimens of M. californianus: M. edulis shells may then be heavier. Shells of the two species are different in shape, with Mytilus edulis being wider (p < 0.001, Harcer, 1967, table 5). Byssal thread material is produced by Mytilus calzfor- nianus in greater quantity than by M. edulis (p < 0.001, Harcer, 1967, table 6). This disparity is reflected by the difference in effort required to remove individuals of the two species from a rock face. Mytilus californianus re- quires greater effort when similar sized mussels are com- pared (Harcer, 1970a). Shells of Mytilus edulis bear few check rings in compa- rison with those of M. californianus (Harcer, 1970a) ; Page 390 M. edulis grows to a maximum length of around 12 - 15 cm under favorable conditions, whereas M. californianus attains 20-25 cm or perhaps more. Thick shells and strong byssal threads both can be regarded as adaptations to heavy wave shock. A third species of mussel, Septifer bifurcatus (Conrad, 1837), also occurs intertidally on the Santa Barbara coast (rarely on pilings) and is similar physically to Myti- lus californianus in that it has a thick shell and ap- proximately the same dry body weight, length for length, as the latter species. Also, there is no significant difference between mean shell weight of the two species. Maximum size attained by Septifer is 3.4-4.5 cm, but effort required to remove individuals from the substra- tum is greater than that required to_remove similar-sized M. californianus (Harcer, 1970a). The pressure which must be exerted to crush Septifer shells is greater than for similar-sized M. californianus individuals (p <0.001, Harcer, 1967, table 27). Mytilus edulis shells were far more brittle than those of either M. californianus or Septifer. During June 1965, when the study was initiated at 340 pilings of Ellwood Pier, approximately 4 were without mussels. The mussel clumps themselves were comprised principally of Mytilus californianus; M. edulis made up from 10% to 50% (by numbers) of half the clumps, with remaining populations trailing off to effectively zero rep- resentation (there were, however, almost always a few individuals of Mytilus edulis in “pure” M. californianus clumps). If competition occurs between the two species, evidence of this should, presumably, be present within the clumps. Accordingly, several populations were dissected and care- fully examined. Clumps of differing sizes were chosen, some composed of both species and others almost entirely of Mytilus californianus. Before removing samples from pilings, the outside mussels were sprayed with white en- amel paint, so providing an objective character by which individual mussels could be identified as to position occu- pied in the clumps. Animals completely or partly covered with paint were recorded as “outside,” and the rest as inside mussels. In mixed aggregations most of the M. edulis occur on the outside of the clumps; juvenile M. edulis (up to 2.5 cm in length, measured from the poste- rior hinge to the anterior siphon region) tend to be found on the outside of the clumps, while juvenile M. californi- anus tend to occur within the body of the clumps (HarcEr, 1968). Mussels at the bottom of the clumps are longer than those growing at the top, and overall, M. californianus tends to be larger than M. edulis (Figure 1). Evidence for competition seemed to be present in both mixed and pure mussel clusters. Those mussels taken from THE VELIGER Vol. 14; No. 4 Mean length (cm) 1 2 3 Distance from top of clump (feet) Figure 1 Relationship between height on mussel clump and mean size of mussels. One standard deviation is plotted each side of the mean. @ Mytilus edulis © Mytilus californianus the inside of clumps were very different in appearance from mussels growing on the outside. Individuals of Myti- lus edulis tended to have thick, heavy shells (p < 0.001, Harcer, 1967, table 10) and many “check rings” (p < 0.001, Harcrr, op. cit., table 11) (see HarcEr, 1970a for a discussion on formation of check rings) ; in addition, compared with individuals taken from the outside clumps, those inside were often found deformed and twisted and had lower body weights (p< 0.001, Harcerr, 1967, table 12). Shells from dead M. edulis were common throughout the clumps, particularly on the inside; they were also quite common within the clumps which were principally com- prised of living M. californianus (HarcErR, op. cit., tables 13 and 14). Mytilus californianus taken from inside clumps tended to show differences from outside mussels paralleling those for M. edulis. However, shell weights of inside mussels were not significantly higher than those from the outside; in fact, the reverse tended to be true (p < 0.05, Harcrr, 1967, table 15). For those on the inside, check rings were more numerous (Harcer, 1970a) but shells retained their normal shape. Dead M. californianus shells from Vol. 14; No. 4 inside the aggregations were very rare and were almost absent from the outside regions. One explanation for this disparity in frequency of dead shells from the two species might be that Mytilus califor- nianus dissolves in sea water faster than M. edulis. Accor- dingly, several batches of shells were immersed mixed with living mussels in cages placed 2 feet below low water. Re- sults indicated that M. edulis shells (4-5 cm long) dis- integrated in 2 to 4 months of continual immersion in sea water, while those of M. californianus were still quite solid after 6 months’ immersion, finally crumbling at 9 to 12 months. It seems unlikely, therefore, that shells from dead M. californianus could have dissolved within the clumps, leaving only M. edulis shells. An extensive investigation was made into the relation- ship between position occupied within clumps and body weight of mussels. Sampled mussels were heated for a few minutes at 90° C in water (this caused the shells to gape open, allowing easy removal of the “body” and adductor muscles; the heating process did not significantly alter body weight of the animals). The bodies were then dried for at least 24 hours at 80° C in a forced-draught oven and were then weighed. The effect of intertidal position was most noticeable in Mytilus edulis. Mussels growing on the clump tops, 7. e., high up in the intertidal, were consistently lighter than those growing at the bottom (p < 0.01, Harcer, 1967, tables 18, 19). This was not true for M. californianus; generally, there appeared to be no difference in body weight between specimens taken from the top or bottom of the clumps for this species. However, considerable vari- ation existed here, but there was no consistent trend; sometimes an individual clump had heavier mussels on the top portion, while other samples indicated heavier mussels on the bottom. Differences in body weight between mussels growing inside clumps and those growing on the outside showed a similar trend for both species, those on the inside were lighter than those on the outside. For Mytilus californi- anus this reduction was significantly greater for mussels growing in the center of a large clump (12 feet in circum- ference) than for a medium-sized clump (8 feet in circum- ference) (p < 0.01, Harcer, 1970, table 20). Small Mytilus californianus (2-5cm) inside clumps contain approximately the same amount of meat as those outside. Larger individuals have significantly lower body weights inside than outside clumps, probably because the large mussels tend to press against each other, while the small ones presumably fit within the interstices. Only one medium-sized clump containing both species was investigated fully, but small and large Mytilus edulis THE VELIGER Page 391 were affected to the same degree (Harcer, 1967, table )\- Evidence most suggestive of competition occurring with- in mussel clumps was provided by the presence of nu- merous shells from dead Mytilus edulis within aggre- gations of living M. californianus only. These shells were inclined to be even heavier and more “robust” looking than shells taken from M. edulis individuals growing with- in mixed clumps, or those growing in relative freedom outside (p < 0.001, Harcer, 1967, table 21). The preceding observations led to the following hypo- thesis: Mytilus edulis settles on the outside of the clumps or throughout the clump matrix. Subsequently, with growth of M. californianus, pressure is exerted on M. ed- ulis individuals within the clumps; these are eventually crushed or in some way bound by byssal threads and jammed together so that they die. Since M. californianus grows to a larger size than M. edulis, individuals of M. edulis on the outside of the clump would eventually be incorporated into the clump matrix where a similar fate would befall them. EXPERIMENTAL METHODS The following description of experimental techniques used to investigate competition between the two species of mussels is taken largely from Harcerr, 1970b. Mussels used in experiments were placed in wire mesh cages suspended intertidally at various heights from cross- girders at Ellwood Pier or from marina floats in Santa Barbara Harbor. Cages were cylindrical in shape (dia- meter 7 inches or 17.78 cm, height 84 inches or 21.5 cm) constructed from galvanized hardware cloth. Components (wire sections, etc.) used in cage constructions were laced together with braided nylon cord and the entire unit was coated with epoxy resin. This coating served to give rigid- ity to the nylon binding and at the same time to cut down any leaching of zinc ions which might affect enclosed mussels. A log normal distribution of mussel lengths was chosen to represent mature mussel populations, since this was similar to the distribution of Mytilus californianus within clumps on Ellwood Pier (Harcer, 1968). The mussels used ranged in length from 2.5cm up to 10cm (for size classes and frequencies, see table 1, Harcer, 1970b). Mytilus californianus individuals occurring with- in clumps are often much larger than 10cm, but this tends to be the upper size limit for M. edulis. A log nor- mal distribution most accurately mimics that of M. cah- fornianus in natural clumps (Harcer, 1968), and although the distribution of M. edulis tends to be normal, or bi- Page 392 modal normal if both juveniles and adults are present, it seemed advisable to use an identical size distribution for both species in order to be sure of eliminating any effects which might arise as the result of size differences. Cages containing populations of mature mussels were constructed from 4-inch (1.27cm) aperture hardware cloth and a total of 90 mussels was placed within each cage (equal numbers of the two species for mixed popula- tions). Individual mussels used in the experiments were marked in the following manner: after drying, a small patch was scoured on the shells with sandpaper, code numbers were written on the roughened surface with white ink, and a small drop of clear epoxy resin was placed over the symbols and allowed to harden overnight. The maximum length of each animal was recorded in centimeters (accurate to 2 decimal places), between the anterior hinge and the posterior siphon regions at the commencement and conclusion of the experiment (mus- sels were removed from water for approximately 12 to 24 hours for marking, etc., and mortality ranged between 10 and 15% as a result of this procedure). All mussels used in the experiments were taken from clumps at Ellwood Pier no more than one day before marking. Before and immediately after marking the ant- mals were kept in running (non-recirculating) sea water. Laboratory containers were well aerated and mussels spent a maximum of 3 days between removal from the pier clumps and replacement at the pier within experi- mental cages. Two methods were used to study supposed competitive processes occurring between the two species of mussels. The first involved mixing populations of mussels with ap- proximately the same size distribution as found within the mussel clumps on the pier. The second method in- volved using groups of juvenile mussels (1.5 - 2.5 cm long) to establish the effect one species might have upon the other when both were newly settled. Experiments with Artificial Mature Mussel Populations An experiment using a 3-way factorial design was set up involving 2 species, 3 intertidal levels, and 4 treatments. The top, middle, and bottom intertidal levels correspon- ded to the top, middle, and bottom of the mussel clumps occurring on Ellwood Pier pilings (Harcer, 1968). The 4 treatments consisted of different arrangements of mus- sels within cages: Treatment 1 consisted of surrounding one species in the center of the cage by the other species; treatment 2 - the reverse; treatment 3 consisted of mixing individuals of both species as evenly as possible; and treat- THE VELIGER Vol. 14; No. 4 ment 4 of Mytilus edulis and M. californianus alone. This experiment was initiated before I was aware of behavioral differences which exist between the two species (HARGER, 1968). Briefly, M7. edulis individuals react to pressure im- posed upon them by crawling against such pressure, where- as M. californianus react slowly or not at all. Thus, the first 3 treatments probably became identical since M. edulis tended to arrange itself on outer surfaces of the caged clumps. Only cages containing pure M. californianus and pure M. edulis (3 replicates of each) were run at the mid-intertidal level. All other treatments within the de- sign were replicated 5 times. An extension of this experiment consisted of setting up 2 replicates of the following 3 treatments in Santa Bar- bara Harbor: evenly mixed Mytilus edulis and M. cali- fornianus; pure M. edulis; and finally, pure M. califor- nianus. Cages were suspended from marina floats in such a way as to be approximately 1 foot (30cm) below the water surface at all times. The complete experiment was started during August 1965; at Ellwood Pier, 3 of the aforementioned 5 repli- cates were left in the sea for 6 months before removal (including the mid-tide cages) and the remaining 2 repli- cates were withdrawn after one year. After determining whether individual mussels were alive or dead, I recorded for each: growth increment, new check rings, and position within the mussel clumps (2. e., inside or outside). The numbers of new recruit mussels within the cages were also noted. When the 12-month cages were recovered, dry body weights and dry byssal weights were recorded separately for each mussel, as were the number and species of crabs present in each cage. Experiments with Juvenile Mussel Populations Competition between juvenile mussels (1.5 - 2.5 cm long) involved 3 treatments, each replicated twice: (a) pure Mytilus edulis (200 individuals): (b) pure M. californi- anus (200 individuals) ; (c) M. edulis mixed evenly with M. californianus (100 individuals of each species). Indi- vidual animals were not marked, all were measured at the start and at each inspection. Cages containing them were plastic kitchen colanders (10 inches or 25.4 cm in diameter) placed face to face and lashed together round the edges. The maximum diameter of holes in the colan- ders was + inch (0.63 cm). All cages were first suspended from Ellwood Pier in October 1965 at the low intertidal position only. The first 3 inspections were made at inter- vals of one month. Thereafter, in order to reduce effects of disturbance that might influence the outcome of the experiment, the interval was increased to 2 months for Vol. 14; No. 4 the next 2, and to 4 months for the last 3 inspections. In all, a total of 19 months’ growth was recorded. A further experiment using juvenile mussels was set up during Jan- uary 1966 to check growth and the effects of competition in both rough and calm waters. The 2 locations used for this experiment were Ellwood Pier (rough water) and Santa Barbara Harbor (calm water). The experimental populations (200 individuals) were set up in wire hard- ware cloth cages (4-inch or 0.63 cm aperture) and posi- tioned in the same manner as previously reported, at the pier (lowest level) and the harbor. In the harbor 3 treatments (pure Mytilus edulis; pure M. californianus; and both in even proportion) were the same as reported for the previous experiment, together with a parallel set at Ellwood Pier. Two additional treatments (M. edulis and M. californianus in the ratio of 3:1 and the reverse) were also used at the latter site. These were designed to investigate the effect of differing initial proportions of the 2 species on the outcome of the competitive process. A checking interval of 4 months allowed time for un- disturbed growth, and the experiment was maintained until September 1966 at Ellwood Pier and May 1967 at Santa Barbara Harbor. RESULTS oF COMPETITION EXPERIMENTS Growth Information concerning growth characteristics of both species was obtained from the previously described experi- ments and is presented in Harcer (1970b). In summary: (1) At Ellwood Pier (rough water), populations of Mytilus californianus grew faster than those of M. edulis (although at low intertidal levels small individuals of M. edulis grow faster than M. californianus of equivalent size). (2) In Santa Barbara Harbor (quiet water), Mytilus edulis populations showed more growth than M. califor- nianus populations. (3) Growth of both species is reduced at high inter- tidal levels from that shown at low intertidal levels. Growth of small individuals of Mytilus edulis decreases more sharply from low to high intertidal levels than that of M. californianus. Growth of large mussels of both spe- cies is reduced by the same degree from low to high inter- tidal levels. (4) The greatest overall growth for both species oc- curred at Ellwood Pier. At the lower clump levels Mytilus edulis grew at a greater rate than M. californianus for approximately the first year; 7. e., until M/. edulis reached a length of 5 - 5.5 .THE VELIGER Page 393 cm; thereafter, growth fell off and almost ceased by the time the mussels reached a length of 10 cm. Growth of M. californianus did not decline appreciably until at least 15 cm was reached (2-3 years), and exceeded growth of M. edulis after a length of about 6 cm was reached; the difference between the two became increasingly great thereafter. At the upper clump levels growth rate of M. edulis never exceeded that of M. californianus. Competition Experiments Involving Small Mussels at Ellwood Pier The first inspection (November 1965) of the experiment set at Ellwood Pier in October 1965 disclosed crawling behavior of Mytilus edulis (HarcEr, 1968), which en- abled it to arrange itself on the outside of mixed species clumps. The experiment was initiated with M. edulis pop- ulations significantly smaller than the M. californianus populations (Harcrr, 1970b, figure 11). After one month’s growth all the AZ. edulis populations taken together were significantly larger than M. californianus (p < 0.001, Harcer, 1967, table 28). The pure M. edulis populations at this time were larger than the pure M. californianus clumps (p < 0.001, Harcer, ibid., table 30). After 2 months’ growth (December 1965), the above statement was still true, but by this time M. edulis populations grown in pure culture were significantly smaller than M. edulis populations grown in competition with M. califor- nianus (p < 0.001, Harcer, ibid., table 31). Presumably this was because the M. edulis individuals in the mixed cages were able to arrange themselves on the outer re- gions of the clumps with M. californianus in the center. Mytilus edulis consistently on the outer regions of mixed clumps grew more than populations from the pure M. edulis clumps, a proportion of which were always on the inside, suffering consequent growth reduction. In March 1966, after 5 months’ growth, a difference between the 2 treatments of Mytilus californianus became apparent. Those populations growing in competition with M. edulis were significantly smaller than those growing in pure clumps (p< 0.05, Harcer, 1967, table 32). This difference increased at subsequent stages, then de- creased. I concluded, therefore, that the presence of M. edulis growing on the outside of the M. californianus pop- ulations resulted in decreased growth of the latter species. The experiment was maintained for 19 months. In May 1966 (after 7 months) the clumps were placed in large cages (diameter 9.5 inches, height 12 inches) made of 34-inch aperture hardware cloth. Sometime after Septem- ber 1966 the two cages containing pure Mytilus edulis were lost in a storm. One cage containing pure M. cali- fornianus was lost sometime after January 1967. Maximum length of mussels per cage (cm) Oct Jan June Jan May 1965 1966 1966 1967 1967 Time Figure 2 Maximum size of mussels occurring in each cage throughout dura- tion of competition experiment involving juvenile individuals. @ Mytilus edulis © Mytilus californianus At the last reading (May 1967) the following size re- lationships were observed. Two populations of Mytilus edulis from the mixed cages together were significantly larger than the remaining pure M. californianus popula- tion plus those from the mixed cages (p < 0.001 Harcer, 1967, table 33). There was still a slight difference between M. californianus grown alone and those grown in competi- tion with M. edulis (p < 0.05), but by this time the size difference between the two species was almost eliminated. To illustrate this point further, Figure 1 records the size of largest mussels found per cage at each check point. Only at the first and last check points is M. californianus as large as M. edulis. THE VELIGER Vol. 14; No. 4 This experiment indicated no difference in mortality for either species between mussels growing in mixed or pure species cages. The reshuffling following each inter- ruption for purposes of measurement may have contrib- uted to this by relieving mortality factors such as crab pre- dation and mutual interference. Crawling behavior provides the initial competitive ad- vantage which Mytilus edulis enjoys over M. california- nus. The presence of M. edulis outside of mixed clumps tends to inhibit the growth of the enclosed M. calzfornia- nus. However, evidence from pure M. californianus clumps indicates that this species inhibits its own growth to a greater extent than the presence of M. edulis does. Five months after the start of the experiment it was found that mussels growing inside pure Mytilus caltfor- nianus clumps were significantly smaller than those grow- ing outside of the same clumps (p < 0.001, Harcer, 1967, tables 34 and 35). Further, M. californianus devel- oping inside pure M. californianus clumps were signifi- cantly smaller than those surrounded by M. edulis (p < 0.001, Harcer, ibid., table 36). It would seem that M. edulis inhibits the growth of M. californianus in a less efficient manner than M. californianus itself does and that the advantage M. edulis enjoys is almost entirely due to its crawling behavior. (The effect of enclosure within clumps is discussed below in the case of the adult mussel clumps. ) Results from the competition experiments using small mussel clumps consisting of differing ratios of the 2 species were parallel to those obtained previously. There was no tendency for higher concentrations of Mytilus edulis to inhibit the growth of M. californianus to a greater extent than that shown by the 1: 1 ratio. This experiment was, however, influenced by crabs settling in the cages and preferentially attacking M. edulis, so that after 8 months all treatments tended to be similar. (This will be discussed in detail in the section dealing with predation. ) At low intertidal levels, there seem to be two immediate advantages possessed by Mytilus edulis over M. califor- nianus: (1) crawling behavior and (2) initial growth greater than that of M. californianus. The first is the only one possessed by M. edulis growing at upper clump levels. When individual mussels in a clump are quite small (2-4cm), the crawling behavior results in a distribution of Mytilus edulis which may cut down the available free water supply to those individuals enclosed within the clumps. Small mussels fit together snugly and have very small gaps between them. As small mussels grow, spaces among outside members of the clump increase greatly, allowing mussels which were formerly completely cov- ered to protrude among those outside. Figure 3 records Vol. 14; No. 4 60 on i=) aS i=) nN oO Number of Mytilus californianus on outside iss} ° 10 Nov Jan June Sook 1965 1966 : 1966 1966 Time Figure 3 Number of Mytilus californianus individuals appearing on the out- side of mixed species clumps at successive inspection points of the competition experiment involving juvenile mussels. the number of M. californianus appearing on the outside of the 2 mixed-species clumps at successive inspections. The number increased progressively until the 6" inspec- tion and thereafter remained almost constant (numbers af- ter the 6" inspection were not plotted). This, together with the large size which M. californianus attains, would seem to constitute the mechanism by which M. californianus finally overgrows M. edulis and incorporates the latter into the matrix of the mussel clumps. Competition Experiments Involving Small Mussels at Santa Barbara Harbor All cages in the harbor received heavy settlements of Mytilus edulis between April and September 1966 (5 or 6 M. californianus recruits per cage were also discovered at the first inspection, but not thereafter). The pure M. californianus population and the mixed-species cage re- THE VELIGER Page 395 ceived 128 and 196 M. edulis recruits, respectively, during the month of April. In May these recruits were measured and returned to their respective cages. From this point, both cages containing M. californianus must be regarded as mixed-species cages. As the experiment proceeded, the number of M. californianus in the cages progressively diminished until at the last inspection (16 months) the populations had been reduced to 10% of the original numbers. This progressive elimination of M. californianus was caused by the presence of small M. edulis clustering over the outside of the clumps. A large amount of silt settled out from the still harbor waters into the clumps and formed a heavy glue-like mud in the center that ap- parently smothered the mussels in the middle (Harcer, 1968). Competition Experiments Involving Adult Mussels at Ellwood Pier Since small mussels exhibit growth patterns differing from large mussels, each population of mussels was divid- ed into 2 groups for the purpose of analysis. The first was comprised of all mussels originally smaller than 4 cm, and the second of those larger than 5 cm. Mussels between 4 and 5 cm were not included in order to make a clear distinction between small and large animals. The “middle- sized” mussels may be regarded as “‘fill” within the various clumps. In the case of the small size class, Mytilus edulis devel- oping on the outside of population cages placed at lower levels grew significantly faster than M. edulis which were started off, mixed evenly with M. californianus, enclosed by M. californianus, or even in cages containing only pure M. edulis (p < 0.01, Harcer, 1967, table 50). (This dif ference was detected by an a priori single degree of free- dom test based on the previously established fact that juvenile mussels on the outside of clumps grow faster than those on the inside.) This observation implied mussels deliberately placed on the outside of cages were probably more favorably oriented than those which had had to crawl through a group of M. californianus. Again, as for the juvenile populations, pure M. edulis populations showed lower overall growth than M. edulis from mixed cages. There was no significant overall difference among the various treatments imposed on the six month M, edulis populations set at the upper piling level. However, for the 12-month interval, M. edulis populations set up on the outside of mixed groups in the top cages showed sig- nificantly more growth than those treated otherwise (p < 0.001, Harcer, 1967, table 59). Page 396 THE VELIGER Vol. 14; No. 4 In the 6-month group Mytilus californianus individu- als placed initially on the outside of the clumps grew significantly faster in upper cages (but not the lower ones) than animals from other treatments (p < 0.001, HarceEr, 1967, table 52). At both upper and lower levels M. cali- fornianus grew more slowly when developing by itself than when in the company of M. edulis (p < 0.05, Har- GER, 7bid., tables 52 and 53). (The a priori justification for this last comparison was obtained from the previously reported competition experiments involving juvenile mus- sels, where it was found that M. californianus inhibited itself to an extent greater than the extent of the inhibi- tion imposed by M. edulis.) For larger mussels of both species, analysis indicated that the original treatments were not associated with dif- ferences in amount of growth for either top or bottom cages for both the 6- and 12-month intervals (mussels immersed for 12 months of course grew more than those immersed for 6 months). (a) Effects of Enclosure on Growth It would seem that evidence of competition which could be revealed by differing growth rates was masked by movement of Mytilus edulis. An attempt was made to counter this behavior by containing groups of M. edulis in small cheesecloth bags which were then placed in the center of M. californianus clumps. Unfortunately, the cloth rotted too quickly, thus allowing the M. edulis to crawl to the outside of the experimental cages before the clumps became solidly bound up with byssal threads. Although mussels originally arranged within the cage clumps became displaced as a result of the re-arranging process undertaken by Mytilus edulis, some individuals of both species were trapped inside the clumps. In cages immersed for 6 months, the “outside” mussels were sep- arated by spray painting (in this and later sections, the term “inside” mussels refers to individuals selected in this manner). Pure species populations yielded from 10 to 20 such “inside” mussels per cage. Mixed-species treatments provided from 5 to 10 inside M. californianus individuals and 0 to 5 M. edulis per cage. (b) Mussels from Bottom Levels Mytilus californianus and M. edulis individuals from in- side both the mixed- and pure-species clumps grew less than those on the outside of the same clumps (p < 0.01, Harcer, 1967, tables 70-72). There was no significant difference between growth of M. californianus individuals from inside the pure clumps when compared with those from inside mixed-species clumps. On the other hand, M. edulis individuals from the inside of mixed-species clumps grew less than individuals from pure-species clumps (p < 0.01, Harcerr, ibid., table 73). The overall goal in the experiment involving the use of small cheesecloth sacks, designed to retain artificially set “inside” populations of mussels in place, was not achieved; however, growth increment of individual Myti- lus edulis retained inside the clumps was significantly lower than those on the outside (p < 0.001, Harcer, 1967, table 74). Growth of small M. edulis is reduced by an amount significantly greater than that of large mussels, as a result of developing inside the clumps in all treat- ments. This is also true of M. californianus. Using infor- mation from the above described experiments, the per- centage growth reduction experienced by a 3 cm mussel resulting from enclosed growth was: for M. californianus growing within pure M., californianus clumps 46.02% for M. californianus growing within mixed-species clumps 44.76% for M. edulis growing within pure M. edulis clumps 27.50% for M. edulis growing within mixed-species clumps 47.48% for M. edulis growing within mixed-species (cheesecloth) clumps 60.64% Of the two species, Mytilus edulis is most sensitive to development in mixed species associations. Growth re- duction for M. edulis is relatively slight as the result of developing inside clumps of its own species, but much greater when M. californianus is incorporated into the clump matrix. (c) Mussels from Upper Levels Growth of mussels confined to the center of the upper cages was reduced approximately the same amount (when compared to that of the outside mussels) as that for the bottom cages (p < 0.001, Harcrr, 1967, tables 76, 77). Categories involving pure- and mixed-species populations for top cages were dispensed with when examining growth of Mytilus edulis, since it was impossible to identify suffi- cient “inside” mussels from these groups. The “mixed” and “pure” categories were retained for the analysis of growth increment of Mytilus californianus on the inside and outside of the upper cage clumps. Again, growth was significantly less for the inside mussels. No sig- nificant difference could be detected between M. califor- nianus individuals confined within pure-species cages and those within mixed cages. The percentage growth reduction attributable to de- velopment within both mixed and pure clumps taken to- Vol. 14; No. 4 gether (upper level) for Mytilus edulis (calculated for a 3 cm individual) was 42%, which is similar to that shown by those inside the lower clump group (see above). Mytilus californianus growing on the inside of mixed-spe- cies clumps suffered 45% reduction, and within the pure- species clumps 34% reduction in growth. However, these reductions are relative to the growth shown by the ad- jacent outside mussels. The actual sizes of the inside mus- sels providing data for these last 2 percentages are not significantly different from one another. The disparity between the 2 values results from the fact that mussels developing on the outside of the “pure” cages did not grow as much as those on the outside of the mixed cages. The growth of the internal “pure” M. californianus mussels was 50% less than the outside individuals from the mixed cages. This also indicates that effects of compe- tition by M. californianus individuals on themselves are greater than are effects imposed by individuals of M. edulis. An individual of M. californianus on the outside of a clump and surrounded by M. edulis individuals evi- dently experiences a far less rigorous environment than when surrounded by members of its own species. Competition Experiments Involving Adult Mussels at Santa Barbara Harbor Mussels of both species under 4cm in length grew at the same rate in the pure- and mixed-species clumps. The 4 to 5cm mussels were included in the “large” group, since the total number of animals used was considerably less than at Ellwood Pier, and it seemed advisable to use all available data. In the “large” group, Mytilus edu- lis grew faster in pure culture than in mixed (p < 0.05) ; however, M. californianus showed no difference in growth from these 2 treatments. OTHER EVIDENCE ror COMPETITION Check Rings as Evidence for Competition The frequency of check rings on a mussel shell may be used as an indication of the degree to which factors, such as wave impact, may adversely affect these animals. An increasing number of check rings is an indication that such a factor (or factors) is increasing in effect. Increas- ing check ring frequencies occur on mussels from low to high intertidal position, with increasing exposure to wave impact and inside mussel clumps as opposed to outside (Harcer, 1970a). In colder climates, annual check rings THE VELIGER Page 397 may be laid down (Seep, 1969a), but no evidence of this was found in the Southern California population. Frequency of check rings on mussels in the bottom cages from the six-month group were analyzed. When growing with Mytilus californianus, M. edulis individuals possess more rings per length of new growth than when growing alone; those growing on the inside do not have a signifi- cantly greater number of rings than those on the outside. However, those growing inside mixed populations possess more rings than those inside pure M. edulis clumps (p < 0.001, Harcer, 1967, table 78). Results for Mytilus californianus are less easily inter- preted; however, the following trends are separated: (1) Those individuals inside the clumps have more rings per unit length. This is true for the overall comparisons and for the pure and mixed populations separately. (2) There is no difference, in terms of the number of rings per unit shell length, between individuals growing inside pure clumps and those inside mixed-species clumps (Harcer, 1967, table 79). Evidence for Competition Obtained from “Dry Body Weight” Data Data obtained from the cages left in place for the 12- month period indicated that Mytilus edulis from both top and bottom cages possessed heavier body weights when growing in pure culture cages as opposed to those from mixed-species cages (p < 0.001, Harcer, 1967, tables 81, 82). For M. californianus growing in the bottom cages, no significant difference in body weight could be detected between those mussels growing in pure cultures and those in mixed-species cages. Results from the top cages indicate that mussels from pure M. californianus cages were heav- ier than those from mixed-species cages (p < 0.001, Har- GER, op. cit., table 84). Mytilus californianus from top cages show no significant changes in body weight when growing inside or outside mussel clumps. Body weight comparisons between mixed and pure pop- ulations of both species growing in Santa Barbara Harbor indicated no significant differences between these treat- ments (body weight provided by both species from the Ellwood Pier lower cages were significantly higher than those within the Harbor cages [p < 0.001, Harcer, 1967, tables 88, 89]). When total growth increment data obtained from mus- sels growing in bottom cages were examined, it was found that Mytilus californianus did not reduce the growth of M. edulis in mixed-species populations (see above). How- ever, there was a significant reduction in body weight of M. edulis growing with M. californianus (when compared Page 398 with weights achieved when growing in pure culture). This reduction was 33% in top cages and 58% in the bottom cages. When growing with M. edulis, the reduction in body weight for M. californianus is not significant in the bottom cages, whereas in the upper cages reduction was 10% and significant (HarcEr, of. cit., table 91). Evidence for Competition Based on Mortality of Mussels Within the Adult Cage Experiment (a) ELLWOOD PIER At Ellwood Pier, mortality fell most heavily upon My- tilus edulis. For the 6 month period August 1965 to Febru- ary 1966, 76 M. californianus and 127 M. edulis were re- covered dead from 28 cages (top and bottom only). This discrepancy between the two species was even greater for the 12 month interval, where a total of 90 M. california- nus and 374 M. edulis were recovered from 21 cages. THE VELIGER Vol. 14; No. 4 For both species the number of dead mussels did not significantly differ between the top and bottom positions for the first 6 months. At the end of 12 months this was again true for Mytilus californianus, but this time M. edulis had a significantly larger proportion of its dead occurring within the top cages (Table 1A) ; indeed, the large increase in mortality of this species was owing al- most entirely to a greater proportion of animals dying in top position. It is probable that these mussels were killed by the heavy storms which the area experienced between late December 1965 and the end of February 1966. The 6-month cages were removed from the pier during Feb- ruary 1966 and at that time many of the M. edulis within the top cages were in very poor condition, the flesh of the mantle lobes appearing quite thin and parchment-like. Unfortunately, a laboratory accident prevented retention of body weight records. By the end of the second week in March 1966, large numbers of M. edulis in the upper cages of the 12-month group were dead. In addition to this circumstantial evidence, I have shown that growth of Table 1 Differences between mortality suffered by Mytilus edulis and Mytilus californianus under differing experimental conditions (see text for explanation) > z eet ie fea eee Test Group 2S aoa g & on Identification oP OO8 bs % August 1965 to February 1966 Mytilus edulis, top 282 450 Mytilus edulis, bottom 97 450 90.30*** “ Mythceliommuetion 33 450 Mytilus californianus, bottom 50 450 N.S Mytilus californianus, pure, top 25 270 Mytilus californianus, mixed, top 17 405 6.85** B Mytilus californianus, pure, bottom 24 270 Mytilus californianus, mixed, bottom 10 405 Be 2 Bees Mytilus edulis, pure, top 15 180 C Mytilus edulis, mixed, top 56 405 6.20** Mytilus edulis, pure, bottom 10 180 Mytilus edulis, mixed, bottom 46 405 N.S August 1965 to August 1966 Mytilus edulis, pure, top 129 180 Dp Mytilus edulis, mixed, top 153 270 3.929* Mytilus californianus, Harbor, 42 90 mixed x Mytilus californianus, Harbor, 48 180 TALAE pure Mytilus californianus, Harbor, 67 135 F small Mytilus californianus, Harbor, 23 135 ONS O ria large Vol. 14; No. 4 M. edulis is restricted by moderate wave shock (HarcEr, 1970a) and that M. edulis is more susceptible to effects of intertidal exposure than M. californianus. Two further items of evidence supporting the conten- tion that competition occurs between adult populations of the two species emerge from the 6-month mortality data. First, at both upper and lower levels, mortality of Mytilus californianus in pure M. californianus population cages was significantly higher than in the mixed-popula- tion cages (Table 1B). Second, mortality of M. edulis populations growing in the mixed cages at the top level was significantly greater than that occurring within pure M. edulis populations (Table 1C); this was not so for the bottom level, however. ‘There was no significant difference between deaths in pure culture Mytilus edulis or M. californianus between the upper and lower cages. These results may be accounted for in the following manner: selection against mussels which are intolerant of crowding and squeezing, etc., is probably high in a pure Mytilus californianus clump, since the physical character- istics of this species promote formation of solid, tightly bound clumps. The comparatively loose clump structure which is formed when M. edulis is incorporated into a mass of mussels undoubtedly relieves pressure on all mem- bers; hence, M. californianus has lower mortality in such a matrix. Conversely, the addition of M. californianus to a group of M/. edulis considerably strengthens the resulting clump. Mytilus californianus individuals anchor their strong byssal threads to any surface they can reach, in- cluding members of the other species, which may then be drawn closely together; this perhaps reduces the effi- ciency of feeding. I recovered several specimens of M. edulis from the mixed-species cages which, though yet alive, were incredibly twisted and distorted, some with pieces gouged from the edges of the shells revealing gaps partially cemented in and others with cracked hingelines. I often found, in the course of disassembling mixed clumps, specimens of M. californianus growing in such a manner that the sharp posterior end of their shell pro- jected onto the posterior end of individual M. edulis. In such cases, a definite notch had been carved into the shell of M. edulis by that of M. californianus. Therefore, I have no hesitation in stating that competition does oc- cur between adult populations of the two species. Field evidence indicates this to be the case and information obtained from experiments is sufficient to lend substantial backing to the claim. Table 1D shows, for the 12-month group, evidence that Mytilus edulis growing with M. californianus suffered lighter mortality than when growing alone in the upper cages. This difference was associated with the extremely THE VELIGER Page 399 heavy mortality incurred by this species in the top cages. Of 450 individuals set out, 375 died; harsh environmental conditions could have been responsible for this mortality, which may have been eased somewhat by the presence of M. californianus individuals sheltering M. edulis (Har- GER, 1970c). (b) SANTA BARBARA HARBOR Similar mortality was suffered in this location by each of the two species (90 Mytilus californianus, 87 M. edulis). Mortality within the pure and mixed populations of M. edulis did not differ and there was no difference in the mortality of small and large mussels (small mussels are, in this case, defined as individuals smaller than the median length for each species in each cage). Mortality in Mytilus californianus populations, how- ever, was significantly higher in mixed culture than in pure (Table 1E). Further, in both pure- and mixed-spe- cies clumps, more small individuals died than did large (Table 1F). This disparity in the mortality of the two size classes may be understood if it is recalled that in pure M. californianus clumps the juveniles tend to occur with- in the center. In the harbor, silt settlement builds a filling of thick mud within the clumps (Harcer, 1968, 1970b) ; this undoubtedly killed the smaller mussels. Large mussels simply project from centers of clumps and therefore tend to be clear of contained mud. Mytilus californianus devel- oping in mixed-species clumps will usually be left in the center as M, edulis crawls to the outside of the clumps. Tue EFFECT or PREDATION on Mytilus edulis anp Mytilus californianus Mussel predators abound in all locations discussed in this study. No fewer than 9 invertebrate predators exhibit a preference for Mytilus edulis to M. californianus. ‘These are: two species of sea stars, Pisaster giganteus (Stimpson, 1857) and P ochraceus (Brandt, 1835) (LANDENBERGER, 1968) ; 5 species of muricid gastropods, Thais emarginata (Deshayes, 1839) and Acanthina spirata (Blainville, 1832) (W. Murdoch, personal communication), Ocenebra poul- soni Carpenter, 1864, Ceratostoma nuttalli (Conrad, 1837), and Jaton festivus (Hinds, 1843); and finally 2 species of crabs, Cancer antennarius Stimpson, 1856 and Pachygrapsus crassipes Randall, 1839 (a third species of crab, Pugettia producta (Randall, 1839), eats few mussels and shows no preference). Preferences for the last 5 species mentioned above were determined in the labora- tory (Table 2A, 2B, 2C, 2D, 2E, 2F), although for most species field evidence also substantiates these findings. Page 400 Investigation of the competition experiment involving small mussels set in varying proportions at Ellwood Pier indicated that cages containing higher proportions of My- tilus edulis supported a higher concentration of crabs (Cancer antennarius) (Figure 4). In these cages preda- tion had fallen most heavily on M. edulis, as shown by or iS) Crab biomass (grams) EN 0) 50 100 150 200 Original number of Mytilus edulis per clump Figure 4 Relationship between biomass (wet weight of crabs) and original number of Mytilus edulis set within population cages at Ellwood Pier (January 1966 to May 1966). the large number of fragmented M. edulis shells present. As the experiment proceeded, such selective predation reduced the proportion of M. edulis in each cage. The 4-month interval between check periods was apparently sufficient to allow crab zoeae to settle from the plankton and to grow inside the cages to a maximum recorded cara- pace width of 3 cm. The shorter inspection time interval used in the first experiment dealing with small mussels, apparently allowed crabs insufficient time to enable them to reach a size where they could prey on the caged mus- sels. Disturbances at each inspection time eliminated small crabs as the mussels were cleaned for measuring. Mytilus edulis taken from clumps infested with Thais emarginata can be identified as having been attacked by this snail by the presence of radula holes made by the predator. A sample of dead shells collected from a mixed- species clump indicated that in natural populations a preference is shown for M. edulis (Table 2G). In the THE VELIGER Vol. 14; No. 4 laboratory this preference was so strongly exhibited that M. edulis was almost entirely eliminated from a clump of mussels composed of both species before M. californianus was attacked to any appreciable extent (Figure 5). The snails do not seem to be selecting mussels on the basis of shell thickness (M. edulis shells are thinner), since, when 2 groups of M. edulis differing markedly in this character (one group from Ellwood Pier, the other from Ellwood shore) were presented to ‘Thais, no significant difference in choice was revealed (Table 2H). Both Thais and A- canthina prefer M. edulis and M. californianus to Septi- fer btfurcatus (W. Murdoch, personal communication). Again, neither the way in which the choice is made nor the reason for it are known. 100 od ed ms @ 90 °° y o e 80 . oe a Ya 70 : ow” P} a 60 : ny 50 di Cumulative number of mussels eaten 1 ee Sie) es GS I IG i BS Time (weeks) Figure 5 Rate of predation by Thais emarginata (20 individuals) acting on a mixed species clump of mussels (maximum size of mussels 4.0 cm in length). @ Mytilus californianus BE Mytilus edulis Of the crabs, both Cancer and Pachygrapsus prefer Mytilus edulis to M. californianus, and the latter to Septi- fer (Table 21). That this choice might be based on the relative shell strengths of the 3 species must now receive more consideration. Figure 6 indicates the maximum size of each species of mussel taken by particular individuals of Pachygrapsus. The size of Septifer taken by individual crabs is significantly less than for either of the other 2 species. The data do not indicate such a difference be- Vol. 14; No. 4 THE VELIGER Page 401 Table 2 Relative choices between mussel species made by invertebrate predators 1 2 ‘ite c Goodness Test Predator as COTTON Prey > 2 of fit Identification as O! [MY ey Se lel Ocenebra poulsoni 1 26 of each species M. edulis 49 A 20 individuals per offered weekly (7 week pooled) treatment (laboratory) M. californianus 6 (7 week pooled) 33.62*** Ceratostoma nuttalli 2 20 of each species M. edulis 51 B 8 individuals per offered weekly (5 week pooled) treatment (laboratory) M. californianus 13 (5 week pooled) Cpa syartet Jaton festivus 2 10 of each species M. edulis 34 Cc 5 individuals per offered weekly (5 week pooled) treatment (laboratory) M. californianus 2 (5 week pooled) as Cancer antennarius 6 10 of each species M. edulis 56 D 1 individual per offered in 3-day (45 day period) treatment (laboratory) intervals M. caltfornianus 25 (45 day period) 11.86*** Pachygrapsus crassipes 7 10 of each species M. edulis 208 E 1 individual per offered in 3-day (24 day period) treatment (laboratory) intervals M. californianus 131 (24 day period) 17.48*** Pugettia producta 2 10 of each species M. edulis 34 F 1 individual per offered in 3-day (54 day period) treatment (laboratory) intervals M. californianus 37 (54 day period) N.S Thais emarginata 1 355 Mytilus edulis living M. edulis 60 G feeding on natural popu- in clump lation of mussels (field) 269 M. californianus living M. californianus 29 in clump 4.00* Thais emarginata 1 14 of each prey type Thin-shelled H 8 individuals per offered weekly M. edulis 23 treatment (laboratory) intervals (7 week period) Thick-shelled M. edulis 23 (7 week period) N.S. Pachygrapsus 5 10 of each species M. californianus 82 1 individual per offered in 3-day (27 day period) treatment (laboratory) intervals Se ptifer 21 (27 day period) PIL ors} Feo Pachygrapsus 4 10 of each species M. edulis 201 1 individual per offered in 3-day (27 day period) treatment (laboratory) intervals Septifer 22 (27 day period) a SO Aas x Cancer 3 10 of each species M. californianus 138 1 individual per offered in 3-day (21 day period) treatment (laboratory) intervals Septifer 29 (21 day period) Tilak reses Cancer 3 10 of each species M. edulis it7/ 1 individual per offered in 3-day (21 day period) treatment (laboratory) intervals Septifer 5 (21 day period) oss Page 402 Maximum length of mussels eaten (cm) 2.0 3.0 4.0 5.0 Crab carapace width (cm) Figure 6 Relationship between maximum size of mussels taken and size of Pachygrapsus crassipes. @ Mytilus edulis © Mytilus californianus x Septifer tween M. californianus and M. edulis. This is perhaps because M. edulis, although the weaker-shelled of the two, has a particularly smooth shell which often “pops” out of a crab’s claws when the predator apparently tries to crack it. Mytilus californianus is heavily ridged and so may provide a better surface for a crab to grip. Another factor at work here concerns the manner in which mussels may be attacked by crabs over long periods. Over short periods, attacks are made by the simple act of crushing mussels between the chelipeds. However, crabs can be in- duced to eat progressively larger mussels over long periods by offering large prey exclusively. Under these circum- stances the attack pattern becomes modified, and the predator tends to pick pieces from the posterior “siphon” region of the prey until entrance is gained. By this method both Pachygrapsus and Cancer seem able to open similar sized M. edulis and M. californianus, provided enough time elapses. Mytilus edulis yields readily to attack but M. californianus takes a little longer. Figure 6 also shows that an upper mussel size limit exists for each crab size and THE VELIGER Vol. 14; No. 4 since Pachygrapsus seldom grows above 4.25 cm in cara- pace width, it follows that mussels above 4 cm are safe from Pachygrapsus predation. Figure 7 shows a similar relationship for Cancer crab size and maximum size of mussel attacked. Large Cancer crabs (13 cm) can easily crack individuals of Mytilus cali- fornianus up to 18 cm in length. Small crabs of this genus have a marked effect on the survival of young mussel pop- ulations. Figure 8 shows the inverse relationship between the numbers of recruits (both species) found in the 12- month adult competition cages at Ellwood Pier and the number of Cancer crabs found in the cages. Small mussels were absent or very rare within cages containing crabs, and extremely numerous within cages free from Sa ° = S ww) iS) Maximum size of mussels eaten (cm) [S%) = - 0 o — (=) 2.0 3.0 4.0 5.0 6.0 7.0 Crab carapace width (cm) Figure 7 Relationship between maximum size of mussels taken and size of Cancer antennarius. @ Mytilus edulis © Mytilus californianus crabs. Intertidally, Pachygrapsus may commonly occur at densities of 1 to 5 per square foot. Subtidally, small Can- cer crabs occur at similar densities (Table 3). These crabs (2 - 4.cm carapace width) may eat from 5 to 7 individuals of M. edulis | - 2 cm in length per day and 2 - 4 M. cali- fornianus, and Pachygrapsus of similar size may consume 3-9 M. edulis (Harcrr, 1967, table 127). At least 6 to 8 weeks from settlement are required before the mussels become sufficiently large so that crabs can no longer eat them. In 7 weeks, therefore, 4 crabs eating 5 mussels per day could eat 980 (say 1000) small mussels. Populations of mussels, to survive on most rocky shores inhabited by crabs, must settle at densities in ex- cess of 1000 per square foot. Mytilus edulis settles at a rather low rate throughout the year and it is reasonably Vol. 14; No. 4 THE VELIGER Page 403 easy to place out collectors suspended from the pier so that crabs from the surrounding structures cannot crawl onto them. Such collectors invariably gather populations Number of mussels recovered 1 2 4 6 8 10 12 Number of crabs Figure 8 Relationship between number of recruit mussels (both species) recovered from 12 months cages and number of small crabs inhabit- ing the cages. Regression is significant. p<0.001. Table 3 Numbers of crabs per square foot occurring at various positions, both intertidally and subtidally BB = 52m Q's ex} 23 T g 5 8 = Place g 52 Zo <2 Zoo. Pachygrapsus crassipes 102 63.0 Ellwood Pier caisson 1.61 412 92.5 Ellwood Pier caisson 4.45 32 1.87 Artificial mussel clump 17.11 Ellwood shore 345 324 (Hewatrt, 1937) Monterey 1.06 Bay 38 4.0 Floats, Santa Barbara Harbor 9.5 43 4.5 Floats, Santa Barbara Harbor 9.55 430 TAES Dawson, 1963 6.43 Cancer antennartus (carapace width 0.5 to 3.5 cm) 13 2.0 outside of submerged collander 6.5, Ellwood Pier 9 2.0 outside of submerged collander 4.5 Ellwood Pier 12 1.5 Sample from Ellwood Pier 8.0 submerged pilings of M. edulis. If, however, the same collectors are placed directly against the pier pilings, no populations of mussels are gathered, presumably because crabs from these struc- tures invade the collectors. During the summer months (May to August) settle- ment by Mytilus edulis increases greatly and it is at that time that most new populations are established (normally, M. edulis recruits move to the outsides of the clumps, thus presumably increasing the chance that they will be taken by predators). Settlement of M. californianus in both years occurred in the winter months, between August and February. The retiring habits of the juvenile M. califor- nianus presumably lessen the probability of predation, since they seem to be comparatively well protected inside the clumps. In the cages removed after the period August 1965 to February 1966, only 90 Mytilus californianus and 1392 M. edulis recruits were recorded. Natural clumps domi- nated by M. californianus contain large numbers of small individuals. The low recruitment recorded above sug- gests that M. californianus juveniles occurring within such clumps (Harcer, 1968) may enjoy high survival rates and owe their numbers to slow but steady recruitment. Mytilus edulis, on the other hand, provides extremely large numbers of recruits, particularly in the warmer months. This in itself might suggest that the concentration of pre- dation on M. edulis by these intertidal predators was, in some way, triggered by large predictable settlements. DISCUSSION anp CONCLUSION Factors Permitting Co-Existence Some of the factors allowing the two species to co-exist over much of their range are listed below: 1. A multiplicity of exposure regions such as those at different levels of the beach, at the front and rear of boulders, on pier pilings, on rocks presenting differing frontal aspects to the surf; all allowing differing competi- tive interactions to take place. 2. A periodicity in occurrence of rough weather: large . patches of mussels may be torn from the shore and pier pilings during winter storms, exposing new patches for subsequent colonization. 3. Structural complexity afforded by larger mussel per se and by the presence of barnacles on shells of large mussels. 4. Variations in pressure exerted by predators. 5. Species ratio-dependent effect of storms. Such factors may be included within the general con- cept of heterogeneity, both in space (nature of the rock substrate, etc), in time (the weather and substrate alter- Page 404 ations caused by the growth of the mussels themselves) , and in the nature of biological interactions (predation and competition). The two species co-exist if populations on the coast are viewed as a whole. In any one place, however, during the competitive process one species may be rated as being more successful than the other. Since the environment is far from stable, today’s advantage may be tomorrow’s drawback: complexity “interpreted” as unpredictability of environmental (meteorological) conditions by the mus- sels is a necessary component of this co-existence. Environmental predictability, represented by relative constancy, is approached only at the extremes of shelter and strong wave exposure; in each, only one species is really successful. Production of offspring by Mytilus edulis (measured as settled individuals) is much higher than that of M. californianus, certainly so during the years 1965-1967. This higher recruitment rate of M. edulis, to- gether with the behavior of the spat which crawl out to the most favorable positions for growth, may help it in co-existence with M. californianus. Through such behav- ior, M. edulis may approach the situation envisaged by SkeLLAM (1951) when he proposed that co-existence might be possible if one species (M7. edulis in this instance) was better at finding and colonizing new places than the other species, even though that species was eventually beaten during subsequent competition. At this stage, it might also be interesting to comment on Hurtcuison’s (1951) concept of a fugitive species, 2. e., one which is specialized in moving into a newly vacated area (as at the start of some successional process) and quickly growing, reproducing, and then going on to an- other such new area. Mytilus edulis in its region of envi- ronmental optima (bays) is probably not a fugitive species; however, in the region of overlap, in exposed situations generally, it quite plainly displays fugitive char- acteristics with respect to M. californianus. Mytilus edulis seems to become sexually mature earlier than M. califor- nianus, at least laboratory experience indicated M. edulis was capable of spawning when 2-2.5cm long and M. californianus at 3.5 cm, usually 4 cm. The immediate outcome of competition at Ellwood Pier between small Mytilus edulis and M. californianus (1 - 2 cm) is different from that between large individuals (7-9cm). Small M. edulis crawl to the outside of any mixed clump and there enjoy a growth rate approxi- mately twice that of M. californianus. This advantage may last until the individuals of M. edulis are 5-6cm long; by this time, however, they no longer interlock as efficiently as before, and so smaller M. californianus are able to protrude between the larger M. edulis, with con- sequent increase in growth rate. THE VELIGER Vol. 14; No. 4 Large Mytilus edulis also tend to move towards the outside of clumps; their mobility is much reduced and those that are successful may become dislodged by wave action. Small specimens of M. edulis may be dislodged only in regions of extreme wave action; an inverse cor- relation exists between the amount of exposure and the maximum size of M. edulis which can survive by them- selves (HarceEr, 1970a). This is complicated by the tend- ency of M. californianus to bind M. edulis firmly onto the substratum, thus raising the maximum size limit in all but the two extremes of the exposure range (HarceEr, 1970c). Individuals of M. edulis not successful in moving out of a clump become bound and anchored by M. californianus within the body of the clump, their growth rate falls and mortality increases because the weaker-walled M. edulis are crushed by their strong-shelled competitors and because growing M. californianus probably expand in such a way as to prevent M. edulis shells from opening properly. Ulti- mately, large successful M. californianus provide a new substrate for colonization by barnacles and young mussels of both species. A laboratory species-interaction similar in form to that described above is reported by Ayata (1968, 1971) in- volving two species of the fruitfly Drosophila. In this in- stance, one species seems to be at an advantage in the larval stage, while the other species is at an advantage in the adult stage. The interaction is frequency dependent and mixed populations of varying proportions show a tendency to converge to constant frequencies, from lim- ited experimental displacement, so establishing a stable equilibrium. The husbanding program (serial replication) involves simplification of the total potential interactive regime between the two species, however all stages of the life cycle are involved, whereas only the sessile stage is involved for Mytilus edulis and M. californianus. An addi- tional difference is that separate environmental resources are exploited in Drosophila by larvae and adults, whereas, in effect, the same resources are competed for by juvenile and adult mussels. It is apparent that competition proceeds in different ways according to the size (and frequency) of the individ- uals involved. Advantages fluctuate between the two spe- cies both in space and time, being modified by predation and by aspects of the physical environment. In many instances, if Mytilus californianus alone were present, wave action could not readily dislodge large numbers of animals, thereby leaving wide areas of bare rock for recolonization. The presence of M. edulis may lead to the elimination of large numbers of M. californianus dur- ing storms (Harcer, 1970c) ; however, storms also exact their toll on populations consisting only of M. california- nus in a density-dependent manner (HARGER & LANDEN- Vol. 14; No. 4 BERGER, 1971; see also SrEp, 1969). After even the heavi- est storms, some patches of both species remain and, since breeding takes place throughout the year, these can then seed new areas. In the last analysis, each species has its own exclusive refuge, though whether decisive use of this is ever made is hard to decide. At intermediate points between the two extremes of exposure, varying proportions of Mytilus californianus and M. edulis are found. It seems that even though com- petition can be demonstrated between the two species, competitive elimination of one by the other is rare in intermediate environments. The relative numbers of both species at any point in the region of overlap probably could be predicted from a continuous knowledge of settle- ment density, weather conditions and predatory pressure, in that order. The field evidence (dead Mytilus edulis shells) indicates that in regions such as represented by Ellwood Pier, M. californianus in some instances has virtually eliminated M. edulis from what must have been mixed aggregations. There are, however, many separate populations on the pilings, each being different from the others in make up (Harcer & LANDENBERGER, 1971). It is because there are so many different populations that M. edulis is always ensured of conditions favoring survival. A model of this system necessarily assumes that changes in the mode of action of the weather and predation pre- vent competitive exclusion by continually modifying ad- vantages enjoyed by each species in different geographical locations. All the active relationships involved have yet to be quantified; nevertheless, the assumption of change in either, or both, wave action and predation pressure in locations outside extremes of shelter and exposure, coupled with variations in proportional representation of species in clumps together with variation in size and age of constituent individuals, provides an infinitely variable background from which co-existence emerges by way of different pathways. In the light of evidence from this study, how much importance may we assign to the effects of competition on the evolutionary process? Plainly, all traits which I con- sider to be important in competitive interaction between these two species appear to be primarily adaptations to the physical environment. Mytilus edulis crawl out from the clumps and so escape burial by silt. The very strong byssal threads and thick shells of M. californianus have obviously evolved in connection with its ability to with- stand heavy wave impact. The main advantages possessed by each species can thus be tied to environmental influ- ences. THE VELIGER Page 405 Competition and the Theory of the “Niche” The basic concept of a “niche” as being associated with dissimilar requirements of different bird species was put forward by GrinneLi (1904). E:ton (1927) advanced the following description: “It is convenient to have some term to describe the status of an animal in its community, to indicate what it is doing ... the term used is niche. The niche of an animal means its place in the biotic environment, its relation to food and enemies.” As originally conceived, this was a rather loose defini- tion, since ELTon (op. cit.) goes on to say: “There is often an extraordinarily close parallelism between niches in widely separated communities. In the arctic regions we find the arctic fox, which, among other things, subsists upon the eggs of guillemots, while in winter it relies partly on the remains of seals killed by polar bears. Turning to tropical Africa, we find that the spotted hyaena destroys large numbers of ostrich eggs, and also lives largely upon the remains of zebras killed by lions. The arctic fox and the hyaena thus occupy the same niches — the former seasonally and the latter all the time.” Hurcuinson (1957) generated a useful abstraction in picturing the niche as an n-dimensional hypervolume defined by the upper and lower values of a series of co- ordinates which represent a set of environmental vari- ables that will permit maintenance of a “steady state” population of a particular species. As SLopopKINn (1961) remarks, “This permits an unequivocal statement of what we would like to mean by an ecological niche, it has several practical difficulties.” McNaucutTon & Wo rF (1970) comment to the effect that most of modern niche theory derives from efforts to relate the competitive exclusion principle to Hutchinson’s n-dimensional niche. Indeed, much abstract theorizing conceming the nature and modes of determination of the niche has been expended on what would appear to be little concrete data; certainly, most analyses scarcely begin to approach the complexity of the problem. The attempts of MacArtHur & Levins (1964, 1967), Levins (1968) and MacArtrHur (1968) to develop a theoretical framework embracing a quantitative formula- tion of aspects of HurcHinson’s (op. cit.) niche incorpo- rating responsive elements as dictated by competitive pro- cesses unfortunately suffer from the use of the entirely ab- stract notion of environmental grain size. MACARTHUR (1968) outlines this concept of environmental structure proposed by himself and Levins (1964) as follows: “We now call a patch of environment ‘fine grained,’ relative to species, if that species comes upon the resources and other Page 406 THE VELIGER Vol. 14; No. 4 components of that patch in the proportion in which they occur. Conversely, if the species can spend a disproportio- nate amounts of time in one resource or the other com- ponent, we call the patch ‘coarse grained’.” Inasmuch as such a classification is dependent on the mode of encounter of mixed resources realized by partic- ular organisms (for whom the classification is relevant), it seems unsound to propose that any organism — the presumed result of natural selection — should encounter mixed resources in the proportion in which they occur naturally. Many studies indicate that predators exhibit distinct choice when actively feeding on several species (ALLEN, 1941; Ivtev, 1961; LANDENBERGER, 1968). As previously mentioned, sea stars actively choose Mytilus edulis over M. californianus; furthermore, Pisaster ochra- ceus may actively modify its hunting behavior by experi- ence (LANDENBERGER, 1966, 1968). To claim that a real environment can be assembled from building blocks of fine-grained patches (MacArtTuHurR, 1968) is tantamount to denying the action of natural selection. In all, these analyses serve to indicate that multiple-resource environ- ments support multiple species by specialization in a one-to-one relationship, a conclusion that differs little from that of WiLuiAMson (1957). The distinction made between co-existence within fine- grained environments by virtue of resource subdivision (MacArtuour, 1968) must logically coalesce with coarse- grained subdivision or habitat specialization, since natural selection would favor recognition of component resources if a successful competitor were to intrude upon a single organism utilizing fine-grained perception (presupposing such an organism could exist). In this regard the axiom of inequality means that the grains or individual constituents of a resource cannot, in fact, be equal to one another. If such constituents are taken as perceptually equivalent, this indicates that no selective advantage can accrue to an individual organism if it adopts tactics which sub- divide the resource as to category. Even the example quoted by MacArtuur & Levins (1964) and again by MacArtuur, (1968) whereby seed dispersal in a plant may be fine-grained but adults arising from successful germination exist in a coarse-grained fashion, must also suffer from the logical consequences of perception. On the one hand, seed dispersal by any plant is less than likely to be random with respect to environment, except possibly in small localized areas; of course, such areas themselves are probably functionally related to parent stock. On the other hand, successful germination may itself be viewed as a form of biological perception. As MacArtuur (1966) has conceded, ideas of com- munities structured on the “broken stick” model should be discarded. In this regard, the work of CoHEN (1966) dealing with an abstraction of competitive theory based on random assignment provides comfortable models in terms of such postulates, in the sense that some carefully selected communities can be shown to mimic result- ant expected distribution of individuals per species (see Mitter, 1967, for a useful discussion of this point). This, however, provides no realistic description of the opera- tion of competitive interactions. There is no reason to suppose either that relative competitive ability of organ- isms in a Community can be measured across one gradient or, in those rare cases where this might be possible, that such ability should be distributed among species according to any regular function. On the contrary, selection is like- ly to determine simple changes in structure and function which remove organisms from each other, in terms of competitive ability, by orders of magnitude. Hence dom- inance is to be expected in organisms particularly suited to any environment. A simple example would encompass the development of rudimentary light perception. In the species interaction under consideration, the principal ob- vious adaptations shown by Mytilus californianus ena- bling that animal to successfully utilize areas of heavy wave impact to the exclusion of M. edulis are develop- ment of thick reinforced shells, strong byssal attachments and conservative mobility characteristics. None of these characters is of particular value in quiet waters, yet all appear to be comparatively minor differences from homo- logous characters in M. edulis. If generalization can be extracted from the example reported here, niche overlap may be widespread and vari- able in nature because the existence of competition need not necessarily lead directly to the phenomenon of compe- titive exclusion (see MiLLer, 1967), notwithstanding the suggestion by Corr (1960) to the effect that genes favor- ing reduction in competitive interactions should be selec- ted for. The use of n-dimensional space to describe require- ments of a particular species in isolation from its compet- itors, predators, etc., is unsatisfactory, principally because this leads to a description of the potential habitat of an organism. Plainly, each different community in which a particular species occurs will result in a differ- ent realized niche for that species (see MILLER, 1967). Differing sets of circumstances in association with the species representation constituting the community in which a given organism finds itself will modify the suc- cessful response of that organism. Since we are presumably dealing at all times with evolving, and therefore changing, systems (species, spe- cies associations, communities, ctc.), it is unlikely that there exists a static and definable niche, except as is represented by a particular species’ distribution from time Vol. 14; No. 4 THE VELIGER Page 407 to time. Any attempt to rate environments in terms of their overall importance to a particular species (Mc- NaucGHTon & Wo tr, 1970) without reference to all possible conjunctions of circumstance, taking into account such seemingly unimportant locations, habitats, areas, etc., as may determine species survival in rare instances, should be regarded with suspicion. Are bays more important to Mytilus edulis than semi- protected shorelines, pier pilings, natural vertical stacks, or even exposed shores? In favorable circumstances, My- tilus edulis is undoubtedly represented more profusely out- side bays than inside. Such an increase in population size extends opportunity for appearance of new genetic mate- rial (by recombination or de novo) ; the ability to colonize and recolonize distant locations must also be increased. In short, access to the area outside the harbors becomes an asset evolutionarily valuable to the species (see Carson, 1968, for a discussion of the consequences of a population “flush” ). Under extremely unfavorable circumstances, 7. e., heavy storms, intense predation, etc., M. edulis could be driven back almost to the confines of the harbors. Quite plainly, both habitats are of importance to this animal — no one area can be said to be more important than another. Harbors, the apparent refuge for M. edulis, also have drawbacks by way of increasing pollution. Contained in the idea of niche seems to be a notion of the necessary principal components of existence, 7. e., those requirements which must be met in order that an or- ganism may successfully reproduce consistently. In a sense, this is the essence of HutcHinson’s (1957) fundamental niche, which utilizes maintenance of steady state popula- tion as a definite central criterion. A simple model of competition in the field would sup- pose that displacement would occur whenever any por- tion of such components are overlapped by a competitive- ly superior organism. Maintenance of co-existence in competitive associations of two or more species would thus depend on one or the other (or a combination) of two mechanisms: (1) Each species involved in competition by virtue of overlap in ecological requirements must enjoy a realized niche of greater extent than defined by its principal com- ponents, thus allowing plasticity in responses to its com- petitors. (2) Since different species are, by definition, exposed to differing selective forces, an oscillating balance in the direction of the suggestion by PimenTeEL e¢ al. (1965) might be struck between a selective response to primary environmental factors and competitive ability as ex- pressed towards a competitor. For instance, the necessity to retain byssal holding strength and stability of behavior as far as limiting movement is concerned for Mytilus californianus, could be balanced by a selective response towards greater mob- ility in order to compete effectively with M. edulis in regions of moderate water movement. As well as this, intra-specific competition among M. californianus indi- viduals may also lead to greater mobility. Successful com- petitors might well be eliminated by severe storms. The same process in counter-action might also be at work in M. edulis populations. At some point along an environ- mental gradient, tight byssal threads may be advantageous in rough water, perhaps even serving to preserve a compe- titive advantage over M. californianus; however, such char- acteristics might well be detrimental to survival in a quiet muddy environment, leading to tight clumps which could result in the suffocation of constituent individuals through accumulation of mud. In most laboratory studies involving competing species, the principal components of the niches of interacting spe- cies are both constrained by, and to some extent deter- mined by, the universe adopted. In such situations, either food or space or both are immediately limiting factors, usually acting in a simple manner. De Bacu (1966) correctly indicates that for practical purposes, either food or space or both can be used to define a niche. In a natural environment, however, both components are subject to infinite subdivision and may be expressed in variable interaction throughout the range of competing species. Ayata (1968) notes in laboratory populations of Droso- phila that the size of a population living in a certain environment depends upon its genetic constitution and that further in the case of mixed species populations sharing the same resources, the numbers of each species depend on the genetic constitution of the competing species as well. Basically, the overall genetic constitution of an organ- ism (its gene pool) determines its potential niche. For any set of circumstances comprised of biological factors (predators and competitors) in conjunction with physical factors, a subset of principal niche components may be defined, dependent on local gene pools. The total repre- sentation of such subsets at any moment in time through- out the range of a species determines a restricted defini- tion of the fundamental niche of that organism. Logically, this may be expanded to include regions wherein a truly steady state population may not theoretically be retained by utilization of the contained resources, yet nevertheless, immigration from regions of over-production may support an essentially steady state population or introduce the genetic basis for successful maintenance. Page 408 The ability of an organism to meet requirements im- posed by future environments is (under the influence of natural selection) determined by the successful reproduc- tion of current gene pools and the extent to which infor- mation gathered by way of experience with past environ- ments is retained within its overall genetic constitution. In this regard, it may be appropriate to define environ- mental stability by way of the ability of a species to deal successfully with such natural variability as may occur, through maintenance of viable populations. The funda- mental niche, like “population equilibrium level” (Har- GER & LANDENBERGER, 1971), can only be defined in terms of an organism’s history and the environment in which it finds itself. In dealing with the determination of niche breadth, Levins (1968) indicates that abundant species are usually the ones which are broad-niched. He concludes that a broad niche is optimal in an environment which is un- certain. In connection with this, AYALA (1968), using Dro- sophila, provides laboratory evidence indicating that arti- ficially increased genetic diversity results in higher popu- lation sizes than are maintained by normal unmodified stocks. McNaucuHTon & Wo rF (1970) believe that genetic diversity determines niche width. They state that it seems likely that the greater niche width of more abundant species would, in fact, be driven by their greater abund- ance. Unfortunately, the seeds of circularity are contained here, because the question of determination of factors permitting the expression of abundance is not dealt with satisfactorily. By this argument, genetic diversity accruing from abundance can reinforce abundance, but not deter- mine it in the first instance. They maintain that there are two possible mechanisms responsible for determination of niche width: 1. relative efficiencies at exploiting critical limiting fac- tors, 2. frequency and carrying capacity of the exploitation speciality. I have argued previously that the only appropriate practical measure of niche width is some function of species representation. For a realized niche, this may be expressed as (1) total area inhabited over a given time interval; (2) total numbers over a given time interval. On a world-wide geographical dimension, Mytilus edu- lis has by far the broader niche of the two species. It would seem that its success is due principally to a combina- tion of both previously quoted alternatives. However, it is apparent that adaptation has been primarily in response to physical (environmental) characteristics; therefore, frequency and carrying capacity of the exploitation speci- ality stand as the primary determining factors. Mytilus edulis also falls into the category of being adapted to THE VELIGER Vol. 14; No. 4 variable habitats, and thus has a broad niche and is dominant, as Levins (1968) expected. The degree of overlap expressed by the two species is determined by relative efficiencies at exploiting critical limiting factors, as well as the extent to which those factors are represented. These efficiencies appear to be under constant and persist- ent selection pressure as immediately unpredictable vari- ation in both environmental and biological factors inter- act. Mytilus californianus, although by definition possess- ing a niche of reduced breadth in comparison to M. edulis on a world-wide basis, nevertheless is just as successful — perhaps more so — when compared with its competitor on the scale of the Pacific West Coast of North America, as far as both the area of distribution and numerical representation are concerned. The niches of both species for this last mentioned region can be described as approx- imately equal but varying volumes intersecting by chang- ing degrees temporally. ADDENDUM In order to avoid the expense involved in publishing tables, few of the data gathered as part of this investiga- tion are recorded in this paper. All experimental analyses referred to, as well as additional information, can be found in the thesis from which this paper is abstracted (Harcer, 1967), available on University Microfilms no. 69-1719, 300 North Zeeb Road, Ann Arbor, Michi- gan 48103. A set of summary tables may be obtained from the author on request. ACKNOWLEDGMENTS This paper forms the last of a series dealing with popula- tion studies on sea mussels in Southern California. The work was done as part of a Ph. D. program at the Uni- versity of California at Santa Barbara under the direction of Dr. Joseph H. Connell. Advice coupled with penetrat- ing criticism of this study (which I was permitted to develop through my own resources) allowed me to attain an understanding of ecological processes, which I have attempted to apply outside the narrow confines of mussel biology. Dr. D. E. Landenberger carried out a parallel study on sea star predation at Ellwood Pier and his work must be consulted to obtain a broad understanding of the system I have described. Dr. John Calaprice, Dr. John Stimson, Mr. Don Potts and Mr. Chris Onuff provided a helpful barrage of criticism which resulted in constant re-evaluation of this work. The Signal Oil and Gas Com- pany made their facilities at Ellwood available for this Vol. 14; No. 4 research, which could not have been accomplished without their aid. Literature Cited ALLEN, K. Rapway 1941. Studies on the biology of the early stages of the salmon (Salmo salar). Journ. Anim. Ecol. 40: 47 - 76 Ayata, Francisco J. 1968. Genotype, environment and population numbers. 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The influence of interspecific competition and other factors on the distribution of the barnacle Chthamalus stellatus. Ecology 24: 710 - 723 Darwin, CHARLES 1859. ‘The origin of species. Dawson, R. 1961. Pachygrapsus crassipes of the Goleta slough. § Unpubl. student reprt. Univ. Calif. Santa Barbara, Biology 150 (28 July 1961) Science 132 (3423): 348 to Murray, London DeBacu, Pau 1966. The competitive displacement and coexistence prin- ciples. Ann. Rev. Ent. 11: 183 - 212 ELTON, CHARLES 1927. Animal Ecology. 207 pp. Frank, P. 1952. _A laboratory study of intraspecies and interspecies com- petition in Daphnia pulicaria (Forbes) and Simocephalus ve- tulus (O. F Miiller) . Physiol. Zool. 25: 173 - 204 1957. | Co-actions in laboratory populations of two species of Daphnia. Ecology 38: 510 - 519 GausgE, G. E 1934. The struggle for existence. Baltimore, 163 pp. London: Sidgwick & Jackson, Ltd. Williams « Wilkins Co., THE VELIGER Page 409 Gause, G. F « A. A. Witt 1935. Behavior of mixed populations and the problem of nat- ural selection. Amer. Natural. 69: 596 - 609 GRINNELL, JOSEPH 1904. The origin and distribution of the chestnut-backed chickadee. Auk 21: 364 - 382 Harpin, Garrett H. 1960. The competitive exclusion principle. Science 131: 1292 - 1297 Harper, J. L., J. N. CLratworrny, I. H. McNaucuTon « G. R. Saver 1961. The evolution and ecology of closely related species living in the same area. Evolution 15: 209 - 227 Harcer, JOHN Rosin E. 1967. Population studies on Mytilus communities. Ph. D. Dissert.. Univ. Calif. Santa Barbara; Univ. Microfilms No. 69-1719 1968. The role of behavioral traits in influencing the distribu- tion of two species of sea mussel, Mytilus edulis and Mytilus californianus. The Veliger 11 (1): 45-49; 3 text figs. (1 July 1968) 1970a. The effect of wave impact on some aspects of the bio- logy of sea mussels. The Veliger 12 (4): 401-414; 9 text figs. (1 April 1970) 1970b. Comparisons among growth characteristics of two spe- cies of sea mussel, Mytilus edulis and Mytilus californianus. The Veliger 13 (1): 44-56; 11 text figs. (1 July 1970) 1970c. The effect of species composition on the survival of mixed populations of the sea mussels Mytilus californianus and Mytilus edulis. The Veliger 13 (2): 147-152; 5 text figs. (1 October 1970) Harcer, JoHN Rosin E. « Donatp E. LANDENBERGER 1971. The effect of storms as a density dependent mortality factor on populations of sea mussels. The Veliger 14 (2): 195 - 201; 6 text figs. (1 October 1971) Hewatt, WILutis GILLILAND 1937. Ecological studies on selected marine intertidal commu- nities of Monterey Bay, California. Amer. Midland Nat. 18: 161 - 206 Hutcuinson, GEorcE EVELYN 1951. | Copepodology for the ornithologist. 571 - 577 1957. Concluding remarks. Quant. Biol. 22: 415 - 427 Ecology 32: Cold Spring Harbor Symp. Iviev, V. S. 1961. | Experimental ecology of the feeding of fishes. Yale Univ. Press, New Haven Kuomp, H. 1961. The concepts “similar ecology” and “competition” in animal ecology. Arch. néerl. Zool. 14: 19 - 102 LANDENBERGER, DONALD E. 1966. Learning in the Pacific starfish Pisaster giganteus. Animal Behav. 14: 414-418 1967. Studies of predation and predatory behavior in Pacific starfish (Pisaster) . Ph. D. dissertation, Univ. Calif. at Santa Barbara 1968. Studies on selective feeding in the Pacific starfish Pis- aster in Southern California. Ecology 49: 1062 - 1075 Page 410 THE VELIGER Vol. 14; No. 4 Lesue, P. H. NicHotson, A. J. 1962. A stochastic model for two competing species of Tribo- 1954. An outline of the dynamics of animal populations. lium and its application to some experimental data. Bio- Austral. Journ. Zool. 2: 9-65 metrika 49: 1 - 25 Levins, RicHARD 3 1968. Evolution in changing environments. Monogr. in Pop. Biol., Princeton Univ. Press, 120 pp. Li, Jerome C. R. 1964. Statistical inference (I). Arbor, Mich., 658 pp. MacArTHUR, ROBERT 1966. Note on Mrs. Pielous’ comments. Ecology 47: 1074 1968. The theory of the niche. In: Population Biology and Evolution, ed. Richard C. Lewontin, Syracus Univ. Press, pp. 159 - 176 MacArtTHur, RoBert & RICHARD LEVINS 1964. Competition, habitat selection and character displace- ment in a patchy environment. Proc. Nat. Acad. Sci. 51: 1207 - 1210 1967. The limiting similarity, convergence and divergence of coexisting species. Amer. Natural. 101: 377 - 387 MacArtuur, Rosert H. « Epwarp O. WILSON 1967. The theory of island biogeography. Popul. Biol., Princeton Univ. Press, 203 pp. McNavucuton, S. J. « L. L. Woir 1970. Dominance and the niche in ecological systems. Science 167: 131 - 139 MILER, Ricuarp S. 1967. | Pattern and process in competition. Adv. Ecol. Res. (ed. J. B. Cragg) 4: 1-74 Acad. Press 1969. | Competition and species diversity. Brookhaven Symp. Biol. no. 22: Diversity and stability in ecological systems, 63 to 70 NeyMaNn, JERZY, THOMAS Park & ELIzABETH L. Scotr 1956. Struggle for existence. The Tribolium model: Biologi- cal and statistical aspects. Proc. 3'4 Berkeley Symp. Math. Stat. Prob. 4: 41 - 79 Edwards Bros., Inc., Ann Monogr. in Park, THOMAS 1948. Experimental studies of interspecific competition. I. Competition between populations of the flour beetles, Tri- bolium confusum Duval and Tribolium castaneum Herbst. Ecol. Monogr. 18: 265 - 308 1954. Experimental studies of interspecies competition. II. Temperature, humidity, and competition of two species of Tri- bolium. Physiol. Zool. 27: 177 - 238 1962. Beetles, competition and populations. 1369 - 1375 PIMENTEL, Davin, Epwin H. FEINBERG, PETER W. Woop & Joun T. Hayes 1965. Selection, spatial distribution and the coexistence of competing fly species. Amer. Natural. 99: 97 - 109 SEED, R. 1969a. The ecology of Mytilus edulis L. (Lamellibranchiata) on exposed rocky shores. I. Breeding and settlement. Oeco- logia (Berlin) 3: 277 - 316 Science 138: 1969b. The ecology of Mytilus edulis L. (Lamellibranchiata) on exposed rocky shores. II. Growth and mortality. Oeco- logia (Berlin) 3: 317 - 350 SKELLAM, J. G. 1951. | Random dispersal in theoretical populations. Bio- metrika 38: 196 - 218 SLoBopkIN, LAWRENCE B. 1966. Growth and regulation of animal populations. Holt, Rinehart & Winston, 184 pp. Soot-RYEN, TRON 1955. A report of the family Mytilidae (Pelecypoda). Allan Hancock Pacific Exped., 20, 1-175 Srussincs, H. G. 1954. Biology of the common mussel in relation to fouling problems. Research, London 7: 222 - 229. WILLIAMSON, M. H. 1957. An elementary theory of interspecific competition. Nature 18: 422 - 425 Vol. 14; No. 4 THE VELIGER Page 411 Notes on Some California Mollusca: Geographical, Ecological, and Chronological Distribution BY ROBERT R. TALMADGE ' Eureka, California 95501 RECENTLY I HAD CAUSE to review an accumulation of benthic molluscan specimens taken from off the coast of northern California. This review consisted of rechecking on both the benthic as well as the geographical localities from which the specimens were obtained, plus a compar- ison of the same species from the fossil fauna of coastal northern California. In several instances definite exten- sions of published ranges of the species were noted; in other instances new or additional data concerning the benthic distribution were obtained, and data on the fossil counterparts to Recent species appeared to warrant a discussion of their distribution in time. These notes are presented in the hope that they will be of use and interest to the malacologist, ecologist, and paleontologist. The study area was limited to the fishing localities visited by the commercial drag boat fleet operating out of Humboldt Bay, California. This extended approximately from the submerged Noyo Canyon off Fort Bragg, Mendo- cino County, California (Lat. 39°30’ N) to off Mack Arch, just north of Brookings, Curry County, Oregon (Lat. 42°15’ N). I was fortunate with the fossil faunas, as the various exposures of the Wildcat Group (OctE, 1953), plus additional sites (all definitely tied into this Wildcat Group) presented a nearly continuous sequence in time from the Upper Miocene to Pleistocene, whereby it was possible to trace many of the species and all of the genera from the faunal change of the Lower Pliocene into the Recent. All of the species and specimens discussed here are in the Talmadge collection, Eureka, California, with the noted exceptions. Polinices lewisti (Gould, 1847) This species is well known from deep intertidal to sub- tidal levels. Material now at hand has been taken at 20 fathoms in crab pots off this area; the Anna W. brought in specimens taken on a sandy mud substrate off Trinidad, Field Associate, Department of Invertebrate Zoology, California Academy of Sciences, San Francisco, California 94118 Humboldt County, California (Lat. 41°05’ N), which had been obtained in a tow made between 75 and 100 fath- oms in depth. The specimens were found amid Polinices draconis (Dall, 1903) and Calanaticina oldroydii (Dall, 1897). Fossil P lewisii are found in several localities, all within the Upper Wildcat fauna and all in a sandy silt- stone within a shallow-water molluscan association. Trophonopsis fleenerensis (Martin, 1914) Martin (1914) described this Pliocene species from near Fleener Creek, in the Centerville Sea Cliffs, Hum- boldt County, California. I have taken specimens from the type locality, and the associated molluscan specimens in- dicate a rather deep water fauna living on a sandy mud substrate. Recent specimens are all collected on a soft sandy mud at a depth of at least 200 fathoms. I cannot see any separation of the Pliocene from the Recent speci- mens by ecological or shell characteristics. Colus tawhitanus Dall, 1918 This species is the common Colus of the study area. It appears to live on a firm blue or grey mud at a depth in excess of 200 fathoms. For a geographical location I use the mid-point of the study region, “off Eureka, Humboldt County, California (Lat. 40°45’ N).” Although another species, C. hallii (Dall, 1873) = “C. halibrectus (Dall, 1891)” of Stewart & STEWART (1949) is known from the Centerville Sea Cliff exposure, and FaustMan (1964) records an undescribed species from the Eel River expo- sures, I have never seen a specimen of C’. tahwitanus in fossil form. Mohmia frielei (Dall, 1891) As far as I know, only one specimen of this species has been obtained from within the study area. A single speci- men was found in a fish box full of broken siliceous sponge, taken from off Mack Arch, Curry County, Ore- gon, in 360 fathoms by the Ina. It is difficult to base the Page 412 THE VELIGER Vol. 14; No. 4 habitat upon a single specimen, especially when no ad- ditional Mohnia have been found in many boxes of this massive sponge culled over for specimens. However, this one specimen does extend the published range of the species to the south (Lat. 42°15’N). I have seen no fossils of this species or genus from northern California. Neptunea phoenicea (Dall, 1891) Although juvenile specimens have reached me from time to time, all collected on a soft grey or blue mud and always from depths in excess of 300 fathoms, I have only a single record of an adult specimen. This one, a male, 94 mm in length, was taken in 380 fathoms off Crescent City, Del Norte County, California (Lat. 41°55’ N) by the drag boat Lynda Dawn. The specimen cannot be separated from Alaskan or Washington specimens by shell characteristics. I have not found this species as a fossil in the area. Neptunea smirnia (Dall, 1919) I have specimens of this species collected as far south as the submerged Noyo Canyon off Fort Bragg, Mendo- cino County, California (Lat. 39°30’ N). Living examples of this species taken within the study area all appear to be restricted to a blue or grey solid mud, and are usually taken from depths between 300 and 400 fathoms. This presents a rather wide range of benthic tolerance, but one that is matched by the local Buccinum strigillatum Dall, 1891. Egg masses are deposited on any solid object, rock, shell, or sponge. Dall’s type locality was in the Straits of Juan de Fuca in 114 fathoms, but Rice (1968) has cited references as shallow as 42 and 65 fathoms. BERNARD (1967) gives the depth as 205 fathoms. Locally, crabbed shells have been found at depths as shallow as 150 fath- oms. FaustMAN (1964), in his paper on the Wildcat fauna listed this species from the Scotia Bluff Sandstone, which is high up in Wildcat time, and is associated with a fauna representative of depths less than 100 fathoms. I have obtained crabbed specimens of Neptunea smirnia from 150 fathoms, as mentioned above; in 1969 a group from Humboldt State College and I watched an eddy current bring in subtidal and benthic specimens of N. tabulata (Baird, 1863) from a deep inshore channel onto the sand flats formed behind Pillar Point on the Straits of Juan de Fuca, Washington. It is quite possible that Faustman’s specimen had found its way into this shallow water deposit by one of these two mentioned methods. I have a fossil specimen, taken in the Centerville Beach exposure of the Wildcat formation, but this site has a fauna comparable to the Recent fauna found in 200 fathoms of water. Clinocardium nuttallii (Conrad, 1837) This sought-after cockle comes into the shallow waters of Humboldt Bay to breed during the winter months; it then is taken for food purposes in the deep intertidal levels on a sandy substrate. It is known to live in deeper waters, but it was a great surprise to me when the Admiral King obtained a specimen for me from 100 fathoms of water off a sandy mud substrate. A short time later the Claremont obtained a second specimen from a similar depth. Both specimens were obtained from off Eureka, Humboldt County, California. In many respects this dup- licates the work of Berry (1954) on Mytilus californianus Conrad, 1837. Thyasira disjuncta (Gabb, 1866) Both Ocre (1953) and FaustMAN (1964) referred to Thyasira bisecta (Conrad, 1849) from the Wildcat Group. Ogle’s locality is now buried beneath silt brought in by the 1964 flood, but his comments on a Lucina and Sole- mya association match the association of mollusks where I found specimens of T. disjuncta on the Eel River expo- sure, which was not exposed until the December 1964 flood altered the river bed, covering one side and exposing the opposite side. Faustman’s locality, B-7640, is across the river from where I found the species and his locality may be noted as an occurrence of similar strata across the Eel River. I have also obtained a specimen, probably Pleistocene, from a sandstone projection extending out into the submerged Eel Canyon, which was caught in the net of the Mineo Brothers. Recent specimens are known from off this same area. Mr. Dan Gotsdall, Biologist for the Eureka Office of the Department of Fish and Game, obtained a specimen from a shrimp grab while making biological studies off northern California. His specimen was obtained from a depth of about 75 fathoms. The Anna W. brought me a specimen taken in nearly 100 fathoms from near Redding Rock (Lat. 41°22’ N), while fishing on a sandy mud substrate. Fragments are obtained from time to time, so the species appears to be not too rare off this portion of the California coast. The flood of 1964 also carried away the overburden from the Upper Miocene sandstone member of the Pullen Formation of Ogle on the east side of the Eel River at Scotia, Humboldt County, California. Among the poorly preserved fossils are two specimens of Thyasira bisecta. However, in this area the two specics appear to be separ- ated both in time as well as in shell characteristics. Vol. 14; No. 4 Macoma astori Dall, 1909 There are some arguments regarding the identification of the Pliocene Macoma astori Dall, 1909 with M. lipara Dall, 1916. Macoma astori is common in some layers of sandstone along the Eel River exposure of the Wildcat Group. I have also obtained a small suite of Recent specimens from a sandy substrate in roughly 50 fathoms of water. I cannot separate the two species, fossil or Recent, nor can I see any difference between Wildcat and Empire fossil material. In my opinion, all are the same, both Recent and fossil; thus, following FaustTMAN (1964) I accept the name M. astori for both the fossil as well as the Recent species. For the record, I cite the locality as “Off Eureka, Humboldt County, California (Lat. 40°45’ N), in 50 fathoms on a sandy substrate.” ADDENDUM Clinocardium nuttallii (Conrad, 1837) After the original data were submitted for publication, the local dragboat fishermen brought in numerous ex- amples of this species, both living and freshly dead speci- mens, all taken on a muddy sand substrate, from depths between 50 and 100 fathoms. It now appears that Clino- cardium nuttallu is more or less common down to 100 fathoms if suitable substrate is available. THE VELIGER Page 413 ACKNOWLEDGMENT I wish to express my sincere appreciation to the men of the drag boat fleet operating out of Humboldt Bay for their cooperation and assistance. Their interest and help have made this project possible. Literature Cited BERRY, SAMUEL STILLMAN 1954. On the supposed stenobathic habitat of the California sea mussel. Calif. Fish and Game 40: 69 - 73 BERNARD, FRANK 1967. | Prodrome for a distributional check-list and bibliogra- phy of the Recent marine Mollusca of the west coast of Canada. Fish. Res. Brd. Canada, Tech. Rept. 2: ii- xxiv + 1 - 261 FAUSTMAN, WALTER F: 1964. Paleontology of the Wildcat group at Scotia and Center- ville Beach, California. Univ. Calif. Publ. Geol. 41 (2) : 97 - 160; plts. 1-3 Oc Le, BurDETTE A. 1953. Geology of Eel River Valley area, Humboldt County, California. Calif; Div. Mines Bull 164: 1 - 128; plts. 1-6 Rice, THomas C. 1968. A checklist of the marine gastropods from the Puget Sound Region. From the mouth of the Columbia River to the northern tip of Vancouver Island. Sea & Shore 169 pp. Stewart, R. E. x K. C. Stewart 1949. Local relationships of Mollusca of the Wildcat Coast section, Humboldt County, California, with related data on the Foraminifera and Ostracoda. Oregon State Dept. Geol. & Min. Industr. Bull. 37 (8): 165 - 208; illust. Page 414 THE VELIGER Vol. 14; No. 4 Additional Data on Flabellina telja (Gastropoda : Opisthobranchia ) BY ANTONIO J. FERREIRA’ anp HANS BERTSCH ’” (1 Text figure) WHILE ON A RECENT expedition on board the research vessel Marisla II, the senior author collected numerous specimens of Flabellina telja Marcus « Marcus, 1967 (Nudibranchia: Flabellinidae), from the southern Gulf of California, Mexico. 'The information obtained extends the geographical and benthic ranges of the species, estab- lishes new records for body lengths of individual animals, and contributes additional behavioral observations. Six specimens of Flabellina telja (Figure 1) were col- lected July 14-15, 1971, on the western side of Isla Las Animas (25°06’ N; 110°33’ W), at a depth of 9 to 12 m. Three other specimens were also observed in the same area, but were not collected. Isla Las Animas is approxi- mately 60 statute miles north of La Paz and 4 miles NE of Isla San José. Previously, only 3 specimens of F telja had been known, all from the rocky intertidal zone at Puerto Pefiasco, Sonora, Mexico (31°18’ N,; 113°35’ W), in a maximum depth of 90cm of water (Marcus & Marcus, 1967: 223). This new locality record constitutes a southward range extension of over 460 miles, and ex- tends the occurrence of F telja into the subtidal region. In the original description, Marcus « Marcus (loc. cit.) gave the following measurements of preserved ma- terial: 11 and 8mm total length; cerata up to 4mm; rhinophores, 2.5 mm; and cephalic tentacles, 3 mm. Since preserved nudibranchs exhibit varying degrees of con- traction because of preservation techniques, our measure- ments of living Flabellina telja are significantly larger. The body lengths of 6 living specimens varied from 20 to 40 mm; the purple, white-tipped cerata measured 4 to 5 mm in total length; rhinophores, 3.5 mm, and ceph- alic tentacles, 4mm long. These longer measurements, made on actively crawling animals, should be taken into account by researchers trying to find or identify F telja. * 2060 Clarmar Way, San Jose, California 95128 2 Mary Help of Christians, P O.Box 7004, Oakland, Califor- nia 94601 All 9 specimens at Isla Las Animas were crawling in mid-day, out in the open, over algae and on top of rocks. Collecting was also attempted in the same area at night. Although the same habitat was examined, no specimens of Flabellina telja were found, suggesting possible diurnal habits for this species. Flabellina telja utilizes 3 methods of locomotion: it swims with lateral bending movements of the body (Mar- cus & Marcus, 1967: 223; Farmer, 1970: 76), crawls Figure 1 Flabellina telja Marcus & Marcus, 1967 (Photograph by A. Ferreira) Vol. 14; No. 4 THE VELIGER Page 415 on its foot, and floats upside down at the water surface. We observed the floating behavior when F telja was in an aquarium. Specimens from this material have been deposited in the Invertebrate Zoology Collections of the California Academy of Sciences, San Francisco. We thank James Carlton and Dustin Chivers for their assistance. We also thank the Beta Research Oceano- graphic Laboratories for their sponsorship of the senior author’s collecting trip to the Gulf of California. Literature Cited FARMER, WESLEY MERRILL 1970. | Swimming gastropods (Opisthobranchia and Prosobran- chia). The Veliger 13 (1): 73-89; 20 text figs. (1 July 1970) Marcus, EvELINE pU Bois-REYMOND & Ernst Marcus 1967. | American opisthobranch mollusks. Stud. Trop. Oce- anogr. Miami 6: viii+ 256 pp.; figs. 1- 155, 1-95 (Dec. 1967) Page 416 THE VELIGER Vol. 14; No. 4 Three New Species of Eolid Nudibranchs from the West Coast of North America RICHARD A. ROLLER Route 3, Mountain Home, Arkansas 72653 (28 Text figures) INTRODUCTION IN RECENT YEARS Many specimens of eolid nudibranchs have been collected along the west coast of North Ameri- ca that have not been previously described in the litera- ture. In many cases, the animals have been sent to me for identification, so that they may be included in checklists, keys, and other pending papers. The present contribution is the first in a series of papers describing these specimens. I owe a debt of gratitude to Dr. Kikutar6 Baba for his many kindnesses over the years in providing me with information and advice. I also wish to thank Gordon A. Robilliard, Gary McDonald, Gale G. Sphon, and Don Cadien for providing specimens and data, and James R. Lance for providing collection data. EOLIDOIDEA Pleuroprocta BABAINIDAE Roller, fam. nov. Rhachidian tooth cuspidate, no lateral teeth present. Babaina Roller, gen. nov. Pleuroproct Eolidoidea with a uniseriate radula (rhachid- ian tooth cuspidate) ; denticulated masticatory margins; rhinophores joined together for half their length, clavi bulbous and perfoliate ; foot corners very produced; cerata in numerous rows along both sides of the body, not in separate groups; dorso-lateral ridge along entire length of body; penis cylindro-conical, unarmed; anal pore lat- eral, posterior to pericardium; genital pore lateral, below 3 to 4™ row of anterior liver. Type species: Babaina festiva spec. nov. The genus is named in honor of Dr. Kikutaré Baba for his more than 40 years of dedicated work with Opistho- branchia and for his many kindnesses to the author. Babaina festiva Roller, spec. nov. Type Material: 1) One specimen collected intertidally under rocks at White’s Point, Palos Verdes Peninsula, Los Angeles County, California (Long. 118°18’30” W, Lat. 33°43’N) on January 27 1971 by Gale Sphon and Marjo- rie Neiswanger; 2) two specimens (20 and.22mm long when alive) collected intertidally at Point Fermin, Los An- geles County, California (Long. 118°17’30” W, Lat. 33° 42’30” N) on 14 May 1968 by Don Cadien. The specimen in lot 1 has been designated the holotype, and has been de- posited in the California Academy of Sciences Department of Invertebrate Zoology, Type series, no. 486. The radula and jaws of the holotype are mounted separately on CAS IZ Type Slide, no. 405. The 22 mm long animal in lot 2 has been designated as a paratype, and has been deposited in the CASIZ Type Series, no. 487. The jaws are mounted separately on CASIZ Type Slide, no. 406. A color trans- parency of the 20mm long animal in lot 2 has been deposited in the CASIZ Color Slide Series, no. 2584. Two other specimens have been collected from the La Jolla, California area during 1968 and 1969 (James R. Lance, personal communication). Eight specimens of what ap- pear to be the same species have been collected from a 400 km long area of the west coast of Honshu Island, Japan, from 1956 to 1964 (Dr. Kikutar6é Baba, personal communication). Description: ‘The living animals in lot 2 were 22 and 20 mm long and 3 and 3.5mm wide, respectively. The 22mm long animal was 8mm long after preservation. Vol. 14; No. 4 ¢@ LTS 7 Q C] vanwe Draw NS x ASCO G Pye Pa oe < Be > cy le {Ss ry =. aay Figure 1 Babaina festiva Roller, gen. nov., spec. nov. Dorsal view of living animal, 20 mm long a — anus g. p. — genital pore dense stippling - yellow light stippling - opaque white dashed - yellowish-white solid -— cadmium yellow-orange diagonal lines —- mauve Figure 2 Antero-ventral view of animal, 20 mm long The holotype was 11 mm long after preservation, live length unknown. Body long and narrow. Head prom- inent with 4mm long simple oral tentacles carried for- ward and diverging distally (Figure 1). The rhinophores are joined by a common stalk for the proximal 4 of their THE VELIGER Page 417 length, and by an anterior web of tissue for the middle 4 of their length. From the stalk, the bulbous, laterally compressed clavi branch. Clavi perfoliated with about 35 leaves (Figures 4 and 5). The eyes are contained within the lower 4 of the common stalk (Figure 3). Foot nar- row, truncated in front, with anterior corners very pro- duced (3mm long), and carried backward (Figure 2). Tail short, bluntly pointed posteriorly, barely showing behind last cerata when animal is crawling. (7, UMN Mt LM te ci Figure 3 Babaina festiva Roller, gen. nov., spec. nov. Side view of head showing oral tentacles and rhinophores Figure 4 Front view of rhinophores Figure 5 Rear view of rhinophores Body color pinkish-red in head region and along sides of foot, lighter pink around cardiac elevation. Proximal 4 of oral tentacles same color as head, distal 4 light yellow. A line of yellowish-white pigment runs along median line of head from base of rhinophores to a point at front of head between oral tentacles. The rhinophore bases are light pink and the perfoliated portion is brown with a light pink stripe running up the anterior edge for the prox- imal 4, to be overlaid with an encrustation of dots of Page 418 yellow pigment in the distal half. The yellow pigment is scattered over the top of the rhinophores (which end in a knob surmounted by a brown tip) and continues as a stripe down the posterior edge of the clavi for about $ of their length (Figures 4 and 5). The pericardial area is covered with opaque white spots, and the dorsal surface of the tail with light mauve interspersed with opaque white spots. The cerata lumina are pinkish-red for the proximal $, followed by a wide band of opaque white, then a narrow band of cadmium yellow-orange, with the tip translucent greyish. The ceratal cores are darker pink- ish-red (Figure 6). Figure 6 Babaina festiva Roller, gen. nov., spec. nov. Individual ceras dense stippling — opaque white light stippling -— light pink solid -— cadmium yellow-orange The fusiform cerata are carried folded downward and backward, and cover the dorsum except in the area of the pericardium and the tip of the tail. They are set in about 22 oblique rows of 2 to 3 cerata each, starting just anterior to the rhinophores. The cerata do not appear to be in separate groups when viewed from above. The lateralmost cerata in each row are on an obvious dorso- lateral ridge that runs the length of the body. The anal pore is ventral to the dorso-lateral ridge, just posterior to the pericardium (Figure 1). The yellowish buccal mass was 0.7 mm wide and 1 mm long. The delicate jaws have a long masticatory process, denticulated for its entire length with several rows of long, pointed denticles (Figures 7 and 8). The yellowish radula was tapered, and contained 16 rows, with one more forming. There were no lateral teeth. The central tooth is broadly arched with the cusp projecting beyond the 6 to 10 lateral denticles on each side (Figure 9). The genital pore is ventral to the dorso-lateral ridge, just below the fourth row of cerata in the anterior liver (Figure 1). The everted penis is long (2 mm) and cylind- rical, tapering to a conical tip with no stylet visible. THE VELIGER Vol. 14; No. 4 \ \ ‘ ws Figure 7 Babaina festiva Roller, gen. nov., spec. nov. Jaw - interior view Figure 8 Enlarged view of masticatory process Figure 9 Radular tooth, fifth from newest in ribbon Discussion: This new family most closely resembles the family Flabellinidae (enlarged to include the Coryphelli- dae by Marcus & Marcus, 1967) in the pleuroproct anus, the dorso-lateral ridge, and the jaw with several rows of denticles. However, members of the family Flabel- linidae, as presently described, exhibit lateral radular teeth; but the characters of the family might be expanded to include animals with uniserial radulae. I believe that a new family should be erected on the basis of this unique character. The only other fully recognized family of the Pleuroprocta is Pleurolidiidae BurN (1966, p. 22) in which the most important character used to create the family was a radular one, a pectinate rhachidian tooth. Whether the common-stalked rhinophores constitute a specific, generic, or familial character remains to be seen. Vol. 14; No. 4 ACLEIOPROCTA EUBRANCHIDAE Eubranchus sanjuanensis Roller, spec. nov. Type Material: Five specimens collected subtidally on the hydroid Sertularella tricuspidata at Friday Harbor, San Juan Island, Washington (Long. 123°00’ W, Lat. 48°32’ N) on 18 August 1969 by Gordon A. Robilliard. The holotype has been deposited in the CASIZ Type Series, no. 488. A designated paratype has been deposited in the same institution as CASIZ Type Series, no. 489. A color transparency of the holotype has been deposited in the CASIZ Color Slide Series, no. 2583. Description: The living animals were between 5.5 and 6 mm long, 2.5 mm wide with simple oral tentacles 1 mm long and simple rhinophores 1.5 mm long. Oral tentacles, rhinophores, and body color translucent greyish. Yellow- ish-brown jaws show through the body wall, the eyes Figure 10 Eubranchus sanjuanensis Roller, spec. nov. Dorsal view of living animal, 6mm long a — anus g.p. — genital pore Figure 11 Antero-ventral view of animal, 6 mm long Figure 12 Individual ceras dense stippling — opaque white light stippling — reddish-orange THE VELIGER Page 419 visible just above and behind them. Foot truncated ante- riorly with rounded foot corners (Figure 11). Posterior of foot bluntly pointed, not showing behind posteriormost cerata when animal is crawling. Opaque white ovo-testes show through the posterior portion of the back. Lumen of the cerata transparent greyish with the knobby liver ducts showing through as reddish-orange. Cnidosac region ob- scured by a band of dense white spots; but the tip is clear (Figure 12). There are 7 rows of inflated fusiform cerata with 3 rows in the anterior liver. There are 2, 4, 4, 3, 3, 3, 2 cerata per row on the left and 3, 5, 4, 4, 3, 3, 3 on the right. Largest cerata (2 mm long) are found toward the median line, those at the margin are smaller (0.5 mm long). Anal pore just anterior to the innermost ceras of the 4" row, and to the right of pericardial elevation (Figure 10). Surface of the cerata rugose, but not tuberculate. Yellowish-brown jaws narrow and pointed posteriorly, with one row of 12 small denticles on masticatory margin (Figures 14 and 15). Radula is “J” shaped with 24 teeth Figure 13 Eubranchus sanjuanensis Roller, spec. nov. Ceratal distribution -—- solid circles represent position of longest cerata Figure 14 Jaw -— exterior view Figure 15 Enlarged view of masticatory process in the older limb and 26 teeth in the newer (Figure 16). Radular formula is 50 * 1-1-1. Central cusp projects beyond the 2 or 3 large lateral denticles, and the lateral plates are broader than rhachidian tooth (Figure 17). Page 420 Rawat Figure 16 ao Eubranchus sanjuanensis Roller, spec. nov. Radular ribbon — O — oldest limb; Y — youngest limb Figure 17 One row of radular teeth The male reproductive system was examined by dissec- tion of a 5.5mm long animal. Gonopore ventral to the 2-4 and 3" rows of cerata on the right side. The penis is conical and armed with a 12.5 stylet that is 2.5 in diameter at its tip. Distal portion of the vas deferens prostatic, proximal part narrow and muscular. A long penial gland is present (Figure 18). Figure 18 Eubranchus sanjuanensis Roller, spec. nov. Male reproductive system Discussion: Of the species presently allocated to Eubran- chus by Epmunps & Kress (1969), 3 are recorded from the west coast of North America: E. occidentalis MacFar- land, 1966; E. olivaceus (O'Donoghue, 1922); and E. rustyus (Marcus, 1961). None of these exhibit the orange- red coloration of E. sanjuanensis. Other differences in radular shape, ceratal arrangement, or reproductive sys- tem separate it from the above 3 species; and from E. THE VELIGER Vol. 14; No. 4 rubeolus Burn, 1964 and E. inabai Baba, 1964, both de- scribed as having red ceratal cores. CLEIOPROCTA FACELINIDAE Emarcusia Roller, gen. nov. Eolidoidea with anus in the cleioproct position; rhino- phores smooth; foot corners very produced; radula uni- seriate, central cusp projecting beyond the lateral dent- icles; masticatory margin with 2 rows of denticles in “V” shape; penis armed with a tubular stylet, and with ma- neuverable accessory male organ; anterior liver branches in form of rows, posterior liver in arches. Type species: Emarcusia morroensis spec. nov. The genus is named in honor of the late Dr. Ernst Marcus, in appreciation of his many years of devoted service to the field of zoological research, and especially in the area of opisthobranchs. Emarcusia morroensis Roller, spec. nov. Type Material: 1) Two specimens collected from hyd- roids on boat landings at Morro Bay, San Luis Obispo County, California (Long. 120°51’ W, Lat. 35°22’ N) on 28 September 1969 by Gary McDonald; 2) 20 speci- mens collected from hydroids on boat landings at Morro Bay, California between 15 November 1969 and 3 De- cember 1969 by the author. The holotype has been de- posited in the CASIZ Type Series, no. 490. A color trans- parency of the holotype has been deposited in the CASIZ Color Slide Series, no. 2585. Three specimens, desig- nated as paratypes, have been deposited in the CASIZ Type Series, nos. 491, 492, and 493. Three specimens, also designated as paratypes, are deposited in the Los Angeles County Museum of Natural History Invertebrate Zoology Type Collection, no. 1615. Description: Living animals were between 3.5 and 16 mm long, the holotype 14 mm long. Body slender (2 mm wide) and long; foot slightly wider (2.5mm) than the body, anterior end wider than the rest of foot. Foot corners grooved anteriorly, very produced (2.5 mm long), and carried backward when animal is crawling (Figure 19). Front of foot truncated, bilabiate. Upper lip slightly notched, mouth a longitudinal slit (Figure 20). Rhino- phores simple, carried upright, and diverging distally, 3.5 mm long. Eyes directly beneath rhinophore bases. Oral Vol. 14; No. 4 THE VELIGER Page 421 tentacles simple, 4.5 mm long. Posterior end of foot nar- row, pointed; extending 4mm beyond last cerata when animal is crawling. Body color translucent greyish, with two light cadmium orange oval spots (composed of scattered dots) on the median line; one spot anterior to and one posterior to Figure 19 Emarcusia morroensis Roller, gen. nov., spec. nov. Dorsal view of living animal, 14 mm long (showing ceratal distribution — solid circles represent longest cerata) a — anus g. p.—genital pore dense stippling — yellow light stippling — light orange solid — cadmium orange dashed — opaque white Figure 20 Antero-ventral view of animal, 14 mm long Figure 21 Individual ceras dense stippling — brownish-black P — posterior edge light stippling — ochre rhinophoral insertion. In some animals a thin line of the same orange color connects the two spots along the median line (Figure 19). A narrow line of light orange runs along each side of head from anteriormost cerata to posterior point of insertion of oral tentacles, and continues along posterior margin of oral tentacles for proximal 3 of their length. Light orange color also present on proximal 3 of rhinophores, in groove between head and foot, and covering pericardium. Distal 4 of oral tentacles and rhino- phores with scattered opaque white dots forming light cap. Scattered heavy opaque white spots along median line of head continuing through inter-rhinophoral space to posterior portion of pericardial area. Starting beneath the pericardium and extending posteriorly, an irregular line (of varying width and ragged edges) runs along median area of back to posteriormost cerata row. Narrow lines of opaque white color branch off from this median line to each ceratal group. Cerata lumen translucent grey- ish, the knobby ceratal cores light ochre with scattered dark brownish-black spots, often concentrated in 3 circular bands. Distal band darker black, and most noticeable in living animals. Concentrated band of reddish-brown pig- ment often located at attachment of cerata to back. Cnido- sacs deep white. Surface of ceratal cores dotted with opaque white spots overlaying ochre color (Figure 21). Cerata arranged in 4 to 5 rows in the anterior liver and 3 to 4 arches in the posterior liver. Posteriormost cerata not distributed in any particular pattern. Cerata carried folded toward the median line and posteriorly; véry little of back shows when animal is crawling. The holotype had the following ceratal distribution: 2, 4, 4, 5, 10, 7, Gy 3 ele Mivonsthe left ande393y5: 6,10) 865 22°25 1 on: the right. Anterior cerata groups are on slightly raised bosses. Longest cerata are located toward the median line, with many very small regenerating cerata at lateral mar- gins. Anal pore located on a low papilla, between arms of first arch of posterior liver (Figure 19). 23 Figure 22 Emarcusia morroensis Roller, gen. nov., spec. nov. Jaw — exterior view Figure 23 Enlarged view of masticatory process Page 422 THE VELIGER Vol. 14; No. 4 The yellowish-brown jaws broad, with a very slight indentation in dorsal edge (Figure 22). The long masti- catory process with 2 rows of denticles arranged in a “V” shape, with the apex pointing toward the end of process. The interior row has 23 short denticles, the exterior row about 13 very small denticles (Figure 23). Radular for- mula: 15 - 22 « 0: 1-0 in 7 specimens observed. Radular plates arched, with central cusp projecting for 4 its length beyond the 7 to 10 long, narrow denticles on each side (Figure 24). The reproductive system was examined by dissection. Spermoviduct divides soon after leaving the ampulla, and a duct from the spermatheca enters at this division point. The oviduct, after a very short distance, enters the female gland mass. Vas deferens narrow and muscular, but soon Figure 24 Emarcusia morroensis Roller, gen. nov., spec. nov. Radular tooth, ventral view Figure 25 Portion of reproductive system dense stippling — penis light stippling — female gland mass cross-hatching — spermatheca dashed — ampulla widens and becomes prostatic (Figures 25 and 26). Penis conical and tipped with a short, straight stylet. The vas deferens leads through the penis to base of the stylet (Figure 28). Connected to side of the glans is a long conical accessory organ that is elongated and contracted violently during copulation (Figure 27). In a cleared specimen, this organ did not appear to be distinct from the glans, and no connection to the vas deferens was ob- served. When retracted, penis is coiled in body area under the jaw. Gonopore located ventral to the 24 and 3"? rows of the right anterior liver, and is divided into male and female openings by a flap of tissue (Figure 27). Spawn a slender opaque white string (0.3mm wide) coiled dext- rally to form a 2.75 mm wide mass. Swimming larvae were noted 5 days after spawn was laid. 26 Ss FGM A AO. 27 28 Figure 26 Emarcusia morroensis Roller, gen. nov., spec. nov. Diagrammatic view of reproductive system A — ampulla S - spermatheca FGM - female gland mass PVD -— prostatic portion of vas deferens P — penis Figure 27 Genital pore with penis everted; drawn from living animal during copulation AO — male accessory organ Figure 28 Enlarged view of penial stylet dense stippling — penis diagonal lines — vas deferens Discussion: The family Facelinidae has been expanded by Epmunps (1970) to include the genera previously allocated to the Favorinidae. This makes the number of genera in the family very large. Since new taxa are being described, including the present one, that do not fit into the older groups, the family will doubtless grow until re- liable separating characters are found. The animals in this family seem to have an endless variety of male organs and copulatory accessories, such as the fantastic appara- tus of the newly described genus Pruvotfolia Tardy, 1969. Perhaps when the use of these structures is more fully understood, they may constitute a character suitable for diagnostic purposes. ADDENDUM Since writing the manuscript for this article, several ad- ditional collections of material have been made which Vol. 14; No. 4 extend the ranges and reinforce the validity of 2 of the newly described species. Babaina festiva: One 17mm long specimen collected by Shane Anderson during October 1971 from kelp hold- fasts at 4.5m depth at Paradise Cove, Malibu Reef, Los Angeles County, California. One 28 mm long specimen collected by Shane Anderson during October 1971 from the Malibu Reef area. Emarcusia morroensis: One specimen collected by James R. Lance from ropes on Dana Landing Boat Docks, Mission Bay, San Diego, California, on 6 July 1969. One 10 mm long specimen and its spawn collected by Gary McDonald on a mussel shell from tires at Texaco Dock, Morro Bay, San Luis Obispo County, California, on 17 October 1971. Six specimens collected by Gary McDonald from short hydroids on tires at Skipper’s Docks, Elkhorn Slough, Monterey County, California on 17 November 1971. Two specimens (7.5 and 8 mm long) collected by R. A. Roller from short hydroids on tires at Virg’s Dock, Morro Bay, on 22 November 1971. Both of these specimens were later observed to spawn in captivity. These collection records extend the ranges of these 2 species to the following: Babaina festiwa — Malibu Reef to La Jolla, California; Japan. Emarcusia morroensis — Elkhorn Slough to San Diego, California. THE VELIGER Page 423 Literature Cited Basa, K1KUTARO 1964. Description of Eubranchus inabai n. sp. from Mukai- shima, Japan (Nudibranchia-Eolididea) . Publ. Seto Mar. Biol. Lab. 12 (4): 13-15; 1 fig. Burn, ROBERT 1964. Descriptions of Australian Eolidacea (Mollusca: Opis- thobranchia). 2. The genera Nossis, Eubranchus, Trinchesia, and Toorna. Journ. Malacol. Soc. Austral. 8: 10 - 22; figs. 1-21 (15 December 1964) 1966. Descriptions of Australian Eolidacea (Mollusca-Opis- thobranchia). 4. The genera Pleurolidia, Fiona, Learchis, and Cerberilla from Lord Howe Island. Journ. Malacol. Soc. Austral. 10: 21 - 34 (16 November 1966) Epmunps, MALcoLm 1969. | Opisthobranchiate Mollusca from Tanzania. 1. Eolida- cea (Eubranchidae and Aeolidiidae). Proc. Malac. Soc. London 38: 451 - 469; figs. 1 - 10 1970. | Opisthobranchiate Mollusca from Tanzania. II. Eolida- cea (Cuthonidae, Piseinotecidae and Facelinidae). Proc. Malacol. Soc. London 39: 15-57; figs. 1 - 24; 3 tables EpmMuNps, MatcoLm & ANNETRUDI KRESS 1969. On the European species of Eubranchus (Mollusca, Opisthobranchia) . Journ. Mar. Biol. Assoc. U. K. 49 (4) : 879 - 912; plts. 1, 2; 8 text figs.; 2 tables (November 1969) Marcus, EvELINE DU Bois-REYMOND & Ernst Marcus 1967. American opisthobranch mollusks. Studies in tropical oceanography (Univ. Miami Inst. Marine Sci., Miami, Flori- da), no. 6, vili+256 pp.; figs. 1-155; 1-95 (December 1967) Tarpy, JEAN 1969. | Un nouveau genre de nudibranche meconnu des cétes Atlantique et de la Manche: Pruvotfolia (nov. g.) pselliotes, (Labbe), 1923. Vie et Milieu, sér. A: Biol. Mar. 20 (2A) : 327 - 346; plts. 1-6 Page 424 THE VELIGER Vol. 14; No. 4 A New Species of Chelidonura from Bahia San Carlos, Gulf of California, with a Synonymy of the Family Aglajidae TERRENCE M. GOSLINER‘* anp GARY C. WILLIAMS’ University of California, Bodega Marine Laboratory, Bodega Bay, California 94923 (1 Map; 8 Text figures) INTRODUCTION ONLy ONE SPECIES in the genus Chelidonura, an opistho- branch gastropod of the order Cephalaspidea, has been known in the Gulf of California; C. inermis (Cooper, 1862) occurs in much of Southern California as well as on the Mexican coast. On December 22 and 25, 1969, the authors together with Scott Williams and Michael Gosliner of Marin Coun- ty, California, collected 3 specimens of an unknown spe- cies of Chelidonura from the intertidal mud flats of San Carlos Bay, Sonora, Mexico. On December 24, 1970, 7 additional specimens were collected from the same area. Later investigation showed the animal to be an unde- scribed species. The drawings presented are by Gary C. Williams. Chelidonura polyalphos Gosliner & Williams, spec. nov. Diagnosis: Straight, shortened, reduced esophagus; posi- tion of the buccal ganglia adjacent to the pharyngo-eso- phageal juncture; elongated thread-like salivary glands; abrupt pharynx; easily identifiable pharyngo-esophageal juncture; small, flattened bursa copulatrix; receptaculum seminis near coelomic gonoduct; smooth, unarmed penial bulb; black body uniformly white-spotted ; small, uniform size (under 40 mm in length) ; shell length to shell height ratio about 2: 1. Type Material: The holotype specimen, on which prelim- inary dissections were carried out, has been deposited at the California Academy of Sciences, San Francisco, Cali- « Permanent address: 859 Butterfield Road, San Anselmo, Cali- fornia 94960 2 Permanent address: 267 Oak Manor Drive, Fairfax, Califor- nia 94930 fornia in the Invertebrate Zoology Type Collection, where it bears the number CASIZ 549. Several paratypes on which the bulk of the dissections were done are in our private collections. Name: The name polyalphos is derived from the Greek qwoAps (==many) and adqgos (meaning a white spot on the skin). The “many white spots,” however minute, and covering the external surface of the animal, are the most striking feature to one observing the living animal for the first time. Taxonomic Position in the subclass Opisthobranchiata: CEPHALASPIDEA AGLA JIDAE Chelidonura polyalphos WORLD SPECIES LIST The following is a list of species names currently in use in the genus Chelidonura A. Adams, 1850: Chelidonura adamsi Angas, 1867 C. africana Pruvot-Fol, 1953 . amoena Bergh, 1905 . conformata Burn, 1966 . evelinae Marcus, 1955 fulvipunctata Baba, 1938 hirundinina (Quoy & Gaimard, 1832) inermis (Cooper, 1862) . nornata Baba, 1949 . mediterranea Swennen, 1961 . nyanyana Edmunds, 1968 DIAAVAGAND AS Vol. 14; No. 4 THE VELIGER Page 425 . obscura (Bergh, 1902) . pallida Risbec, 1951 . perparva (Risbec, 1928) philinopsis Eliot, 1903 plebeia Bergh, 1900 polyalphos Gosliner & Williams, 1972 . sanguinea (Allan, 1933) . tsurugensis Baba & Abe, 1959 . varians Eliot, 1903 . velutina Bergh, 1905 QYAQOQAAAaS Figure 1 Chelidonura polyalphos Gosliner « Williams, spec. nov. dorsal aspect NATURAL HISTORY Type Locality: The type locality of Chelidonura poly- alphos is Bahia San Carlos, 6 km north of Guaymas, Son- ora, Mexico (Lat. 27°55’N; Long. 111°05’W). The region of San Carlos Bay is extremely variable topographi- cally and includes many differing environments. On both sides of the mouth of the bay are found volcanic rock reefs which are quite rugged. Immediately inside of the mouth of the bay and extending along most of the inner shore are areas containing many rocks and providing suit- able shelter for a variety of animals. Along the north shore of the bay, opposite the mouth, runs a sandy spit. To the far north of this spit is a mangrove swamp, and to the south there are extensive mudflats. It is these mudflats that are of interest at present since they represent the only location where Chelidonura polyalphos has been collected. Wave action inside the bay is minimal and tidal action allows a substantial portion of the mudflats (approxi- mately 20000 m7) to be exposed twice daily. At high tide, the water depth covering the mudflats does not ex- ceed 90 cm. Daytime water temperature varies from about 32°C to 15°C from September to December. Daytime air temperature varies from 43°C to 18°C during the same period. It is not known how these seasonal tempera- ture variations affect the population of Chelidonura poly- alphos, since observations were carried out only during the month of December 1969 and 1970. Habitat: Chelidonura polyalphos has been found ex- clusively on the mudflats of Bahia San Carlos. It has been seen crawling in the small intertidal pools, generally less than 2 m in diameter, which contain the algae S'piro- dea filamentosa and Enteromorpha sp. The depth of these pools does not exceed 15 cm at low tide. Haminoea vir- escens (Sowerby, 1833) commonly occurs also in this community as does C. inermis, which, however, is much less abundant. Although dives were made inside the bay down to 3 m, no specimens were observed subtidally. The substrate is light gray in color and composed of very fine silty mud that has a clean sandy texture. It would seem that the main contributions of nitrogenous material cyc- ling in this subtropical marine ecosystem come from a combination of bird guano and various invertebrates and fish that wash ashore. Several large, decaying fish (prima- rily trigger fish, Balistes sp.) have been observed on the mud surface, often half buried. Many bivalve and proso- branch shells can also be found in the same situation. Several species of sea birds come to feed, usually in great numbers, on these mud flats at low tide. Page 426 THE VELIGER Vol. 14; No. 4 e Bahia San Carlos A: Guaymas oA: Mazatlan —>-¥, 8. pie Map of the Gulf of California Locomotion: In a glass aquarium of 15-gallon capacity, at 16.5° C, a 3.7 cm long specimen of Chelidonura poly- alphos crawled on the side wall at a rate of between 6 and 6.5 cm per minute. On flat rock surfaces, the specimen crawled at the same rate. No observations were made of the animal crawling on its natural substrate. Locomotion is accomplished by rapid pedal waves. As the animal pro- ceeds forward, the body is kept uniform in shape and size. Often, however, the animal may extend the parapodia downward while crawling. Feeding: No observations were made on the animal while feeding. However, animals kept in 1-gallon capacity con- tainers and isolated from other species, egested shells of Haminoea virescens. This was observed on 2 occasions; the egested shells did not exceed 5 mm in length. MORPHOLOGY ann ANATOMY External Characteristics: The ground color of the ani- mal is a very dark brown, often appearing black; it is decorated with numerous small white spots, not exceeding 4mm in diameter, which become larger and more numer- ous in certain areas along the dorsal surface, giving a patched appearance. The distribution of white patching is not consistent throughout the animals found, although patches were observed on each individual. Often, these patches may appear as T-shaped bars or straight bars across the shields. The animal, when in sunlight, appears to have a bluish iridescent sheen on the external surface of the contracted parapods. On the inside of the parapods is a greenish tint which gradually blends into the normal ground color of the body. Faint, minute green spots form- ing a V-shape on the inside ventral surface of the caudal lobes were noted in several specimens. The general shape of the animal is typical of the mem- bers of the genus Chelidonura; it is particularly similar to C. evelinae and C. inermis. The posterior folds of the caudal lobes extend behind the animal. The right and left lobes are quite variable with respect to size. In some individuals the left lobe was longer, in others the right lobe was longer; in one individual both lobes were of equal length. The animal, when actively crawling, has the para- podia folded tightly around the latero-dorsal surface. The organism tends to open the parapodia when exposed to strong light, particularly noticeable when it was being photographed in direct sunlight. At the front of the head, just above the mouth, are 2 small projections, found in several species of the genus, and covered with chemosens- ory setae. The setae are also found in C. evelinae and C. inermis, as are setae on the sides of the anterior portion of the cephalic lobes. The cephalic shield covers the anterior and pharyngeal region of the animal, and gives way ab- Vol. 14; No. 4 THE VELIGER Page 427 Figure 2 Chelidonura polyalphos Gosliner « Williams, spec. nov. Diagram of external features B. Ventral view; C. Dorsal view with D. Right lateral view A. Dorsal view; parapodia extended; ruptly to the posterior or visceral shield which covers the mantle and posterior viscera. Collected specimens ranged in size from 20 to 37 mm in length and 5 to 9 mm in width. No specimens observed at the type locality exceeded 40 mm. The holotype, when actively crawling, measured 32 mm in length. Shell: The shell of Chelidonura polyalphos is much re- duced as in other members of the family Aglajidae and contains a large rib-like structure emanating from the central whorl. The rib is thickened on the inside of the shell, which lies across the anal tube and adjacent to the cel — cephalic lobe; cl — caudal lobe; cs — cephalic shield; e — eye; f — foot; g — gill; m — mouth; pos — posterior shield (visceral shield) ; pp — parapod; se — setae digestive gland. The shell color is generally yellowish- brown, becoming lighter in the thinner regions. The shell, viewed dorsally, follows a slight clockwise curva- ture to the right side of the anal region. The shell of the holotype measures 34 mm in length and has a maximum height of 1.8 mm. Digestive System: The digestive system of Chelidonura polyalphos is the most massive organ system in the animal and is composed of 3 basic regions which, when taken to- gether, produce the bulky appearance of the animal’s Page 428 body. These 3 regions are the pharynx, the esophagus, and the digestive gland. The pharynx is a large, 3-sided, muscular hollow or- gan that can be extended and contracted when feeding. It is flexible enough and able to open quite widely to engulf seemingly large prey (such as Haminoea virescens). Running from the posterior to the anterior of all 3 sides of the pharynx and arising from the dorso-posterior por- tion of that organ, is the pharyngeal musculature, com- posed of several flattened, ribbon-like muscles. These are the important agents used in the extension and contrac- tion of the pharynx while engulfing prey. The pharyngeal surface is composed of many striae running perpendicular to a postero-anterior line; it is ivory white in color. The salivary or pharyngeal glands originate from both sides of the dorso-posterior portion of the pharynx just above the pharyngo-esophageal connection. These glands are thread-like, elongated structures that extend back over the top of the esophagus. The animal’s esophagus is a sac-like enlargement of the digestive tract, located between the pharynx and the THE VELIGER Vol. 14; No. 4 digestive gland. The esophagus is flexible enough to be slightly stretched when the pharynx is extended. However, 2 shortened esophageal muscles are attached at one end to the interior walls of the body and at the other end to the right and left sides of the esophagus. This prevents the esophagus from being overly disturbed during pharyn- geal extension. The organ is brownish in color, as seen in the holotype. The digestive gland is the most massive and conspicu- ous organ in the body and surrounds the reflexed stomach and intestine. This gland is grayish in color and is at- tached to the esophagus at its ventro-anterior region. It is covered by the posterior or visceral shield and helps give the animal its rather bulky appearance. Below the posterior shield and covering the digestive gland and main reproductive organs is a thin, white, membranous sheath of connective tissue that is somewhat opaque in nature. This membrane envelops the entire posterior vis- cera, and separation of it from various organs can make dissection a very tedious task. < Figure 3 Digesive system A. Dorsal view; B. Lateral view with section of digestive gland removed to show general position of stomach and intestine a — anus; dg — digestive gland; es — esophagus; in — intestine; m — mouth; ol — oral lip; ph — pharynx; phg — pharyngeal gland (salivary gland); phm — pharyngeal musculature; s — stomach Vol. 14; No. 4 Respiratory Apparatus: The gill is a tripinnate external organ, representing a true ctenidium and has its origin in the mantle cavity on the right posterior part of the body between the internal region of the right parapodium and the visceral shield. When extended, the gill may be seen when one observes the animal from above. Most of the time, however, the structure is concealed beneath the visceral shield. ‘The gill measures 8 mm in length in the holotype and is a dull yellowish in color. It is composed 1mm Figure 4 A. Diagram of gill with lateral branch shown in detail, ventral view B. Diagram of dorsal view of shell THE VELIGER Page 429 of 10 to 12 pairs of lateral branches arising from the main stem. The side branches are further subdivided into 4 or 5 pairs of smaller segments per branch. The main stem is a thickened, flexible and tubular structure and has a slight clockwise curvature to it when the animal is viewed from above. Reproductive System: The reproductive system is ex- tremely compact, small enough to be rather inconspicuous, and hidden by the massive digestive system. The male copulatory apparatus is separated from the rest of the re- productive system and is connected to it only by the narrow seminal groove. The entire system is located ex- clusively on the right side of the body and involves a great deal of connective tissue. The gonopore is located on the right side of the body very near the gill origin. It enters the common atrium, includes the vagina and into which opens the duct leading to the bursa copulatrix. This bursa is a disk-shaped organ usually located on the right upper part of the digestive gland. The albumen gland (or possibly membrane gland) arises from the common atrium and leads into the gono- duct. The mucous gland coils clockwise off from the albumen gland and common atrium. The receptaculum seminis is a small, club-shaped projection that leads direct- ly into the gonoduct (very close to the coelomic gonoduct). The narrow post-ampullar coelomic gonoduct coils tightly, then leads to the enlarged, coiled ampulla and via the pre-ampullar coelomic gonoduct to the gonad. The latter is an enlarged, somewhat flattened spheroid-shaped or- gan located directly to the right and underneath the digestive gland. It is yellowish in color and has a rather bumpy surface texture. The male copulatory apparatus is located very near the mouth in the anterior portion of the body. The penis, when contracted, is bulbous in shape and located directly beneath the pharynx. It is smooth and unarmed through- out. No spines or papillae are present either externally or internally. From the dark, muscular penial sheath extends a proportionally large, club-shaped prostate that is posi- tioned to the right of the pharynx and is quite conspicuous when the cephalic shield is removed. The seminal groove is a narrow, ciliated depressed line in the interior wall of the animal, leading from the penial aperture to the gono- pore. Nervous System: The anatomically very complex nervous system of Chelidonura polyalphos involves 11 ganglia, including 4 paired ganglia. The cerebral ganglia, the largest and most concentrated nervous region in the ani- mal, is composed of right and left ganglia and located on the dorso-anterior surface of the contracted pharynx. The Page 430 THE VELIGER Vol. 14; No. 4 Figure 5 Reproductive system Pp dorsal view of a slightly teased dissection, (not drawn to scale) alg - albumen gland (possibly membrane gland) ; am — ampulla; be — bursa copulatrix; ca — common atrium; gd — gonoduct; go — gonad; gp — gonopore; mg — mucous gland; p — penis; pa — penial aperture; pag — pallial gonoduct; pocg — post am- pullar coelomic gonoduct; pr — prostate; prcg — pre ampullar coelomic gonoduct; ps — penial sheath; rs — receptaculum sem- inis; sg — seminal groove (adjacent column >) Figure 6 Dorsal view of male copulatory apparatus (penis shown partially extended ) Pp — penis; pa — penial aperture; pr — prostate; ps —penial sheath ~ 1.0mm pr cerebral commissure, a thickened bridge located just below the eyes under the cephalic shield, extends across the pharynx and connects the right and left ganglia of the Vol. 14; No. 4 cerebral ganglia. Very close to the cerebral commissure and arising anteriorly from the cerebral ganglia are the paired labial, optic, and cerebral nerves. The labial nerves are composed of small nervous networks, establishing con- nections with the oral lip and general labial region. The optic nerve is a very thin, somewhat transparent connec- tion between the left and right eyes and respective cereb- ral ganglia. The cerebral nerves form a very large and extensive continuation of the cerebral ganglia, extending forward, branching extensively, and forming various con- nections with the cephalic lobes and general cephalic region. Posterior to the cerebral ganglia and slightly lat- erally to them are the pedal ganglia. These are connected anteriorly to the cerebral ganglia and posteriorly by the pedal commissure, which is greatly elongated and extends posteriorly to circuit around the posterior end of the pharynx. From the pedal ganglia arise several sets of pedal nerves which branch at the ends, forming nerve nets and part of the somatic nerve makeup. The pleural gang- lia arise at the posterior of the cerebral ganglia and lie adjacent to the pedal ganglia. The pleuro-pedal connec- tive is quite small and can be seen only when the ganglia are separated during dissection. To the right of the right pleural ganglion is the parietal ganglion, from which arise 2 elongated nerves (labeled nerve 2 and 3 [n? and n‘] in Figure 7). The visceral loop connects the 2 posterior ganglia with the cerebral ganglia (via the pleural gang- lia). Also arising from the cerebral ganglia is the sub- cerebral commissure which circuits the ventral portion of the pharynx and is elongated, allowing passage of the pharynx during extension and contraction while feeding, and the cerebro-buccal connective which extends along the sides of the pharynx and connects the buccal to the cerebral ganglia. The buccal ganglia are located just be- low the pharyngo-esophageal connection on the pharynx. Arising from the buccal ganglia are the pharyngeal and esophageal nerves. The subintestinal ganglion and a fusion between the genital and abdominal ganglia are connected at the very posterior-most of the system. The genito-abdominal gang- lion is considerably larger than the subintestinal ganglion and the conspicuous genital nerve arises from it and ex- tends to the reproductive system. On the left portion of the visceral loop, which connects the cerebral and poste- rior ganglia, arises a short, unbranched nerve (nerve 1). This nerve, as well as nerve 2, extends into the visceral region. Nerve 3 points to the right exterior part of the body. The exact identification of these 3 nerves is very difficult and information concerning them in the literature is sketchy. For these reasons, their identification will not be attempted here. THE VELIGER Page 431 n? ~ 1mm Figure 7 Dorsal view of nervous system (not drawn to scale) bg — buccal ganglion; cbe — cerebrobuccal connective; cc — cerebral commissure; cg — cerebral ganglion; cn — cerebral nerves; e — eye; esn — esophageal nerves; g-+ag — genital plus abdominal ganglia; gn — genital nerve; In — labial nerves; n? — nerve 2; n3 — nerve 3; on — optic nerve; pe — pedal commissure; pg — pedal ganglion; phn — pharyngeal nerve; plg — pleural ganglion; pn — pedal nerves; ptg — pari- etal ganglion; scc — subcerebral commissure; sig — subintestinal ganglion; vl — visceral loop n' — nerve 1; Page 432 DISCUSSION Ecological Relationships: In the intertidal mudflat pools of San Carlos Bay, two species of Chelidonura seem- ingly co-exist within the confines of this subtropical eco- system. Since both C. polyalphos and C. inermis prey on the same species, Haminoea virescens, and live under identical abiotic conditions, it would seem that the two species occupy the same niche. By the principle of com- petitive exclusion expressed by Gause and others in the 1930’s, complete competitors cannot co-exist. That is, complete competitors cannot co-exist permanently in the same niche. Two species must differ in niche requirements in certain features that can reduce competition between them. In the case of the two species of Chelidonura, C. inermis has gone beyond being Haminoea-dependent for food and differs in feeding habits from C. polyalphos in the variety of diet. A dissection of the gut of a 63 mm long specimen of C. inermis revealed a rather large shell of Bulla gouldiana Pilsbry, 1895, in the midgut. BERTscH (1970: 172) documents similar feeding habits of C. in- ermis from the Gulf of California. Since C. inermis is large enough (over 50 mm) to be able to prey on Bulla as well as on Haminoea, this shows a significant differ- ence between the two species. Bulla is not a common animal of the winter mud flats, but is an established member of that mud flat faunal community. Theoretical- ly, by Gause’s principle, if both C. inermis and C. poly- alphos did occupy the same niche in the same stabilized community within the same geographical area, then one would eventually give way to the other until that one disappeared completely. This does not seem to be the case in San Carlos Bay since, as far as our observations have been able to determine, the two species can effectively co- exist and the principle of competitive exclusion is upheld. The fact that the two species have different geographical ranges, however, implies that they also have different physical tolerances. This may explain why the two popu- lations are so numerically dissimilar, 7. e., on December 24, 1970, only two individuals of C. imermis were ob- served, while over a dozen individuals of C. polyalphos were seen. Since the nutritional requirements of Chelidonura in- ermis and C. polyalphos are similar, they are probably competitive species, but since their requirements are not exactly alike, severe or direct competition is not a prob- lem. The generalization that closely related species cannot co-exist, is not upheld in this case, since C’. inermis and C. polyalphos are closely related species. Their relationship on the San Carlos mudflats, as viewed at present, is one of co-existence. Intraspecific predation (cannibalism) and interspecific predation are quite possible, but no observa- THE VELIGER Vol. 14; No. 4 tions have been carried out in this respect at the present time. External Characteristics: As far as general body shape is concerned, Chelidonura evelinae, C. inermis, and C. polyalphos have almost precisely the same structure. Col- or patterns do differ, however. Chelidonura evelinae is dark brown with whitish spots; there are longitudinal yellow stripes on the dorsal surface that “dilate to spots powdered with white. A row of metallic blue spots bor- dered with black accompanies the margins of parapodia, the spots increase with age.” (Marcus, 1955: 95 - 96). In the case of Chelidonura inermis, the ground color can vary from ochre to brown, almost black. Yellow longi- tudinal lines may or may not be present on the dorsal surface. White and blue spots may be observed on the dorsal surface of the parapodia in some specimens. Chelidonura polyalphos is a dark brown with white spots which become concentrated in certain regions of the dorsal surface. No yellow or blue pigmentations are found on any portion of the animal. Shell Characteristics: The shells of Chelidonura inermis are very characteristic; all shells removed from this species possessed a large, cellophane-like wing attached to the normal calcified shell. The calcified portion of the shell seems highly variable, but appears to become elongated with age, while the height remains fairly constant. In Chelidonura evelinae the shell is highly variable in shape and has no transparent extension. The shell seems not to arise from a symmetrical spiralling whorl, as is the case with C. inermis and C. polyalphos. In Chelidonura polyalphos the shell has a much greater regularity of form. It appears that in this species the length to height ratio of the shell remains fairly constant or decreases slightly with age, but not enough shell speci- mens were observed to pronounce this a well established fact. Nervous System: Very little work has been published on cephalaspidean nervous systems, but what has been pub- lished has been very informative. Gurart (1901) provides a very well illustrated text, particularly regarding species of Philine, Acteon, and Haminoea. HorFMANN (1936) also provides excellent detail of nervous systems in cephal- aspideans as well as in other groups of opisthobranchs. Buttock « Horrwcer (1965) also delve into opistho- branch nervous systems, but provide no great detail on cephalaspideans. The nervous system in the family Aglajidae seems to be comparatively consistent anatomically. In Chelidonura polyalphos, several changes have occurred which distin- guish it from the hypothetical ancestral opisthobranch Vol. 14; No. 4 THE VELIGER Page 433 Table 1 Shell Measurements Chelidonura Species: polyalphos inermis evelinae Portion of shell measured total shell clear wing calcified portion _ total shell Specimen Ib eh 8) 2 i 2 wy a 1 Shell length (mm) 3) 35 Bs) WHA GO) 4.8 3.4 2.3 3.0 5 Shell height (mm) 1.6 1.8 1.8 74 4.3 SME M ORS 5 Length:height (ratio) Pt) P40) MS) ez Ue Bo 23 Cosh PB 1 first postulated by Guiart in 1901. In C. polyalphos, the parietal ganglion has migrated to the right and has come in tack with the posterior part of the right pleural gang- lion. Also, the abdominal and genital ganglia have mi- grated together and fused. This fusion has migrated with the subintestinal ganglion to the point where the two are in contact with each other at the very posterior end of the nervous system. HorrmMann (1936) describes a nerve in Haminoea simi- lar to nerve 3 in Chelidonura polyalphos and refers to it as the osphradial nerve with a question mark. Because of this dubious reference, the nerve will not be named here. Neither will we name nerves 1 and 2 for similar reasons. The cerebral commissure in Chelidonura inermis is relatively thickened and has a length to width ratio of 6: 1, while the rather elongated commissure of C. poly- alphos has a length to width ratio of 8: 1. The ratio of cerebral commissure length to cerebral ganglion lobe diameter varies in all 3 similar Chelidonura species. The ratio in C’. inermis is 3 - 2 while in C. polyalphos it is over 2: 1. Marcus (1955) describes C. evelinae as having a cerebral commissure shorter in length than the diameter of a single cerebral ganglion lobe. Digestive System: The digestive system of Chelidonura evelinae is easily distinguished from those of C. inermis and C. polyalphos by its diverticulated esophagus and short, rounded salivary glands. Both C. inermis and C. polyalphos have proportionally longer salivary glands and an esophagus without diverticula. The differences between Chelidonura inermis and C. polyalphos will be examined in greater detail. The buccal ganglion in C. inermis is located approximately 10 mm below the pharyngo-esophageal juncture, while in C. polyalphos of the same size the ganglia are adjacent to the juncture. The relative size of the pharynx to the rest of the body is much greater in C. inermis. The pharynx of this species tapers at the end and gradually gives way to the esophagus. The existence of a definite junction between the pharynx and the esophagus is therefore uncertain. In C. polyalphos, the pharynx ends abruptly and the pharyngo-esophageal juncture is quite evident. The eso- phagus in C. inermis is greatly elongated and reflexed along the right side of the digestive gland to which it is attached at the postero-ventral portion of the gland. In C. polyalphos the esophagus is not elongated and is at- tached to the anterior portion of the digestive gland along the midline. The salivary glands in Chelidonura inermis are flat- tened and ribbon-like in shape, and are located at the dorsal portion of the esophageal-pharyngeal juncture. The right gland extends anteriorly along the right side of the pharynx while the left gland extends anteriorly along the ventral side of the pharynx. In C. polyalphos the glands are proportionately longer than in C. inermis and are thin, thread-like structures located several millimeters above the pharyngo-esophageal juncture. The glands are sym- metrical and extend posteriorly behind the pharynx. Reproductive System: The reproductive system of Chel- idonura polyalphos differs from that of the similar C. evelinae in a significant manner. The position of the duct leading from the receptaculum seminis to the rest of the reproductive system differs in both species. It arises in C. evelinae directly from the albumen gland while in C. polyalphos it arises from the gonoduct between the coel- omic gonoduct and the albumen (or membrane) gland. In Chelidonura inermis, the bursa copulatrix is quite large and conspicuous in relation to the rest of the repro- ductive system. It is considerably smaller in relation to the rest of the reproductive system in C. polyalphos, and it is also rather inconspicuous. Page 434 A. a) dg es ee B. Ts ca us alg ca ed gd gp aa A : al A ie 8 C. D. F. G. H. THE VELIGER Vol. 14; No. 4 Synonymy of Chelidonura inermis (Cooper, 1862) and Aglaja bakeri MacFarland, 1924 Aglaja bakeri is known only from the holotype collected by Dr. Fred Baker on May 12, 1921 at San Marcos Island, Gulf of California. The specimen, in the Califor- nia Academy of Sciences (CAGTC 1736), contains well developed cephalic lobes characteristic of the genus Chelidonura, rather than the simple rounded head char- acteristic of the genus Aglaja. The specimen in question contains a well developed shell with an elongated rib which is applicable to the genus Chelidonura, rather than the more simply rounded shell with a shortened rib found in the genus Aglaja. On this basis A. bakeri should be transferred to Chelidonura. The body color of the specimen is described as “dark brown everywhere, marked with narrow irregular longi- tudinal lines of yellowish white on the cephalic and body shields and on the outer faces of the parapodia. Near the parapodial margin on their outer base is a row of ocelli, composed of light blue, rounded or elliptical, each edged with a narrow band of black, the largest c. .5 mm. in length” (MacFartanp, 1924: 391 - 392). In his analysis of Chelidonura inermis MacFarLanp (1966) states that the color of the body ranges from van dyke brown to ochre and mentions longitudinal, light yellow lines, yet makes no mention of bluish spots. However, on plate 2, figures 1 - 3, the same bluish spots on the parapodial margins described in Aglaja bakeri are illustrated. MacFarianp (1924: 395) describes the shell of Ag- laja bakeri as consisting “of a narrow calcified portion, expanded in front and at the left into a large, thin, membranous extension.” The general color of the calcified portion is a light yellow, deepening somewhat in thicker portions. Although MacFarland makes no mention of the shell of Chelidonura inermis in his 1966 analysis of that species, the authors as well as Mr. Richard Roller of San (< adjacent column) Figure 8 Diagrams in comparative anatomy A. Digestive system of Chelidonura inermis; B. digestive system of Chelidonura polyalphos. C. Portion of reproductive system of Chelidonura evelinae; D. portion of reproductive system of Cheli- donura polyalphos. E. Shell of Chelidonura evelinae (after Marcus, 1955); F. shell of Chelidonura inermis; G. shell of Aglaja bakeri; H. shell of Chelidonura polyalphos (ventral view) a — anus; alg — albumen gland (possibly membrane gland) ; ca — common atrium; dg — digestive gland; es — esophagus; gd — gonoduct; gp — gonopore; ol — oral lip; ph — pharynx; rs — receptaculum seminis Vol. 14; No. 4 Luis Obispo, California, have removed shells of specimens from throughout the Gulf of California and California coasts, and have found them to be identical with that described by MacFarland for A. bakeri and shown in plate 11, figures 16 - 17 of that description. Examination of the specimen of Aglaja bakeri by the authors revealed no contradiction with the description by MacFarland. Based on the above data it must be con- cluded that there is no significant basis on which A. bakeri can be regarded as a distinct species and must, therefore, be considered a junior synonym of Chelidonura inermis (Cooper, 1862). ACKNOWLEDGMENTS We would like to convey our deep appreciation to Dr. Michael T: Ghiselin of the University of California, Bode- ga Marine Laboratory, for his help and guidance. While studying under Dr. Ghiselin we gained the techniques and information necessary to describe this animal. Dr. Ghiselin supplied information to numerous questions that arose during dissections and was instrumental in securing refer- ences and supplying necessary equipment. Without his interest in our findings and willingness to help, the present work would not have been possible. We also thank Michael Gosliner and Scott Williams who helped extensively in collecting the first specimens and in making initial field observations. Our appreciation is extended to Mr. Richard Roller, formerly of San Luis Obispo, California, for taking the first photographs of the animal and for his dissection of a paratype shell. Mr. Roller’s knowledge of and interest in cephalaspideans provided a great deal of information for which we are indebted to him. We also thank Mr. Gary MacDonald of San Luis Obis- po, California, for his compilation of the world list of Chelidonura species. Literature Cited ALLAN, Joyce K. 1933. | Opisthobranchs from Australia. Sydney, 18 (9): 443 - 450; pl. 56 AncAsS, GEorGE FRENCH 1867. Descriptions of thirty-two species of marine shells from the coast of New South Wales. Proc. Zool. Soc. London Basa, KikuTARO 1938. Opisthobranchs of Kii, Middle Japan. Agric. Kyushu Imp. Univ. 6 (1): 1-19 1949. | Opisthobranchia of Sagami Bay, collected by his Majesty the Emperor of Japan. Tokyo. 104 pp.; 50 plts.; 7 text figs. Biol. Lab. 8 (1) :79- 85; plts. 7, 8 (November 1949) Rec. Austral. Mus. Journ. Dept. THE VELIGER Page 435 Baza, KixuTaro & T. ABE 1959. The genus Chelidonura and a new species C. tsurgensis from Japan. Publ. Seto Mar. Biol. Lab. 7: 279 - 290 Bercy, Lupwic SopHus RupoLF 1900. Malakologische Untersuchungen in Semper’s Rei- sen im Archipel der Philippinen. Vol. 4 (2), Lief. 1: 159 to 208 1902. _Malakologische Untersuchungen in Semper’s Rei- sen im Archipel der Philippinen. Vol. 7, Abt. 4, Abs. 4: 313 - 382; plts. 25 - 29. 1905. Die Opisthobranchiata der Siboga Expedition. Siboga Exped. prt. 50: 1 - 248; plts. 1-20 Bertscu, Hans & ALBERIC SMITH 1970. | Observations on opisthobranchs of the Gulf of Califor- nia. The Veliger 13 (2): 171-174 (1 October 1970) Bituincs, W. D. 1970. Plants, man, and the ecosystem. Co., Inc., Belmont, Calif. 160 pp. ButLtocx, THEopoRE HotMeEs « G. ApRIAN HorripGE 1965. Structure and function in the nervous system of inverte- brates. W. H. Freeman and Co., San Francisco & London, 2 vols. Burn, RoBert 1966. Some opisthobranchs from southern Queensland. Journ. Malac. Soc. Austral. 1 (9): 96-109 Epmunps, MALcoLm Wadsworth Publ. 1968. | Opisthobranch Mollusca from Ghana. Proc. Malac. Soc. London 38: 83 - 100 Eviot, Cuar.es N. E. 1903. | On some nudibranchs from East Africa and Zanzibar. Proc. Zool. Soc. London 1903 (II): 250-257 (Aug. 1903) GausgE, G. F. 1934. The struggle for existence. (Repr. 1964) Hafner, New York, 163 pp. GHISELIN, MicHAEL TENANT 1966. Reproductive function and the phylogeny of opistho- branch gastropods. Malacologia 3 (3): 327-378; 7 text figs. (31 May 1966) GutarT, JULES 1900. Les mollusques tectibranches. Causeries scientifiques. Soc. Zool. France 1: 79 - 132; 4 plts. 1901. Contribution 4 l’étude des gastéropodes opisthobranches et en particulier des céphalaspides. Mém. Soc. Zool. France Paris 14: 1 - 219; plts. 1-7; 119 text figs. HorFrMann, Hans 1932- 1940. Opisthobranchia. In: Bronn’s Klassen und Ord- nungen des Tierreichs 3 (2; 3; 1, 2): 1377 pp. Hyman, Lispit HENRIETTA 1967. ‘The invertebrates. 249 text figs. MacFar.anp, FRANK MacE 1924. Expedition of the California Academy of Sciences to the Gulf of California in 1921. Opisthobranchiate Mollusca. Proc. Calif. Acad. Sci. 13 (25): 389 - 420; plts. 10 - 12 1966. Studies on opisthobranchiate mollusks of the Pacific Coast of North America. Mem. Calif. Acad. Sci. 6: vxi + 546 pp.; 72 plts. (8 April 1966) McGraw Hill Inc. 6: vii+792 pp.; Page 436 THE VELIGER Marcus, ERNST 1955. | Opisthobranchia from Brazil. Bol. Fac. Fil. Ci. Letr. Univ. S. Paulo, Zool. 20 (2): 89 - 262; plts. 1 - 30 1961. | Opisthobranch mollusks from California. The Veliger 3 (Suppl.) (I): 1-84; plts. 1-10 (1 February 1961) Marcus, EvELINE DuBois RayMonpD & ERNST Marcus 1967. American opisthobranch mollusks. Stud. Trop. Oce- anogr. Miami 6: viii + 256 pp. 1970. | Some gastropods from Madagascar and West Mexico. Malacologia 10 (1): 181 - 223 Pruvot-Fo., ALICE 1953. | Etude de quelques opisthobranches de la céte Atlantique du Maroc et du Sénégal. Trav. Inst. Chérif: Zool. 5: 1-105; plts. 1-3; 35 text figs. Quoy, Jean René Constant, & JosEPpH PauL GarmMarD 1833. | Voyage de découvertes de I’Astrolabe exécuté par ordre du Roi, pendant les années 1826 - 1829, sous le commandement de M. J. Dumont d’Urville. | Zoologie, Mollusca 2: 321 - 686 RisBEc, JEAN 1928. | Mollusques nudibranches de la Nouvelle Calédonie. Faune de l'Union Frangaise, fasc. 15: 1 - 126 SmitTH, Rosert Leo 1966. Ecology and field biology. Harper & Row, New York, 686 pp. SWENNEN, CHARLES 1961. Ona collection of Opisthobranchia from Turkey. Zool. Meded. 38 (3) : 18 text figs. Tay or, L. R., Jr. 1970. Untaxing taxonomy. Oceans 3 (6): 106 WHITTAKER, RoBert H. 1970. Communities and ecosystems. Macmillan Co., Lon- don, 161 pp. Vol. 14; No. 4 Vol. 14; No. 4 NOTES & NEWS Dr. Leo George Hertlein On January 15, 1972, Dr. Leo George Hertlein unexpect- edly died after a very short illness. In him, the California Malacozoological Society loses a staunch friend and a valued member of the Executive Board, as well as a con- tributing member of the Editorial Board. His kindly and friendly counsel will be missed. We extend our sympathy to his family. Soviet Contributions to Malacology BY KENNETH J. BOSS AND MORRIS K. JACOBSON Museum of Comparative Zoology, Harvard University Cambridge, Massachusetts 02138 WE HAVE PREVIOUSLY PROVIDED lists of the papers in mala- cology published in the Soviet Union and some of the Russian satellite countries (Boss & Jacopson, 1970, The Veliger 13 (2): 199 - 202). There have been some posi- tive responses from workers who would otherwise have overlooked some of these papers. The translations are made from the original citations as they appeared in the section on Invertebrate Zoology of the Referativnyy Zhur- nal, a monthly series of abstracts published by the Govern- ment Committee of the Soviet Ministry of the USSR for Sciences and Technology. During 1970, the editors of the abstracts have divided the section on mollusks into several subheadings, and we have followed the same policy. It is of interest to note that there are comparatively few purely taxonomic papers and virtually no revisionary monographs. There appears to be considerable emphasis on applied subjects — witness the General and Biology- Ecology sections. Further, though we have made no quan- titative study, the sum total of papers appears to be sig- nificantly smaller than that published in the West, or for that matter in America alone. One field of activity has considerable importance for North American workers and THE VELIGER Page 437 should command the attention of malacologists: the study of the fresh-water mollusks of Siberia and adjacent re- gions. The nomenclatorial introductions of Starobogatov alone are substantial and most have yet to be recognized in the West. As we noted previously, we have given the best possible versions of titles of Russian journals. Several are compara- tively well known or well distributed periodicals but many, if not most, are rarely seen in American libraries so we have had to rely on the abbreviations as they appear in the Referativnyy Zhurnal. Additional abbreviations and symbols we have used are: ZL, Zoologicheskii Zhurnal (Zoological Journal) BWHO Byul. Vsemiri. Organiz. Zdrayookhr (Bulletin of the World Health Organization) ES English Summary GENERAL ALYAKRINSKAya, I. O. 1969. Morpho-physiological adaptations in the live-bearing snail Viviparus viviparus. ZZ, 48 (11): 1608-1613 (ES) Beer, S. A. 1969. The search for suitable molluscicides to combat Bithynia leachi — the intermediate host of Opisthorchis fellneus. Second report on Phenasal as a molluscicide. Med. Parazitol. i Parazitarn. Bolezni, 38 (5): 578-582 (ES) Beer, S. A., V. M. Koroeva & A. V. Lirscuitz 1969. Age determination in Bithynia leachi. 1401-1404 (ES) Berrios-Duran, L. A. & L. C. RircHie 1968. The molluscicidal action of india-rubber, saturated with bis(tri-n-buty]) oxide. BWHO 39 (2): 305-307 Berrios-Duran, L. A., L. S. Rircuie « H. B. WESSEL 1968. _ Field elimination tests of molluscicides effective against Biomphalaria glabrata in flowing water. BWHO 39 (2): 311-316 Cuu, K. Y, J. Massoup « FE ARFAA 1968. | Comparative study of the molluscicidal action of copper chlorides and sulphates in Iran. BWHO 39 (2): 316-322 ZZ, 48 (9): 1968. The territorial range and ecology of the mollusk Bulinus truncatus in Khuzestan, Iran. BWHO 39 (4): 604-634 Fittppova, Y.u. A. 1969. The quantity of species of squid of the Atlantic Ocean and perspectives for their commercial exploitation. Trudi Atlantich. nauch.-issled. institut rybn. Khoziaistva i okeanogr., Vyp. 22: 235-270 Gricor’Ev, V. A., V. M. IvcHENKo « A. P. KuLtak 1969. | Hydroreactive motion of aquatic organisms. Resp. Mezhved. Sb., Vyp. 3: 66-71 TocaNnzeEN, B. G. 1969. Conference on the study of freshwater mollusks of Si- beria, Tomsk, 26-28 June, 1969. Izv. Sib. Otd. Akad. Nauk SSSR, No. 15, ser. Biol., Vyp. 3: 151-152 Bionika. Page 438 MinicHeEvy, Yu. S. 1969. The organization of Bathydoris vitjazi n. sp. and the problem of the origin of the opisthobranch mollusks (Opistho- branchia, Nudibranchia). Vestnik Leningrad. Universitet 21: 51-58 (ES) Novikov, E. A. 1969. The inter-institutional science-method conference on the study of fresh-water mollusks of Siberia. Tomsk, 26-29 June 1969. Gidrobiol. Zhur. 6 (1): 130-131 Potareey, N. E. 1969. A modified method for the cultivation of the mollusk Galba truncatula. Uchenye Zapiski Kurskii Gosudarstven- nogo Pedagogicheskogo Instituta 59: 166-169 Ritcuie, L. C. « I. Fox 1968. Laboratory investigations on the molluscicide 2,5 di- chloro-4 nitro-3-phenisalitzilanilid-(FCA): determination of the concentration and estimate of the sensitivity of mollusks of varying ages and dimensions. BWHO 39 (2) : 307-311 Ritcuie, L. S. « L. A. Berrios-DuRAN 1969. Chemical stability of the quality of molluscicides used in water. BWHO 40 (3) : 471-474 Rircure, L. S., L. A. Berrios-DuraNn & R. SIERRA 1969. _ Field elimination tests of a preparation of sodium pent- ochlophenolate — a model in quality of molluscicide with de- layed release of toxicants. BWHO 40 (3) : 474-476 Rocinsxaya, I. S. 1969. On the taxonomy and ecology of the nudibranch mol- lusk Coryphella fusca. ZZ 48 (11): 1614-1617 (ES) Romanova, N.N. 1969. On the commercial mollusks of the Barents Sea. Trudi Vseso. nauch.-issled. institut morsk. rybn Khoziaistva i okeanogr. 65: 436-448 SapyKuHova, I. A. 1969. The utilization of submarine stations established on the bottom for aqualung divers for the investigation of the growth rate of mussels in the Bay of Peter the Great. Morsk. Pod. Vodn. Issled. Moscva Nauka 88-94 Samonoy, A. M. 1970. On the problem of the transportation of the monodak Monodacna colorata (Eichwald) from the Caspian storage lake into Balkash Lake. Rybn. Resursy. Vodoemov. Kazakh- stana i ikh ispol’z., Vyp. 6, Alma-Ata Nauka, 160-162 Samonovy, A. M. « K. V. Smirnova 1970. The colored monodack — Monodacna colorata (Eich- wald) as an object of acclimatization in western Balkash. Rybn. Resursy. Vodoemov Kazakhstana i ikh ispol’z. Alma-Ata Nauka 150-159 Vovx, A. N. 1969. Perspectives for the development of trade in the long- penned squid. Rybn. Khoziaistvo, no. 10: 7-9 ZHALTSANOVA, D. D. 1969. On the investigation of the fauna and biotopes of the fresh-water mollusks of Buriat. Materialy Nauchn. Kon- ferentsii Vses. O.-va Hel’mintologov Moscva 85-87 MORPHOLOGY AntTomonov, Yu. G. & V. RP MaTvEEVA 1969. Investigations on the structure of the organization of the nervous system of the mollusk Planorbis corneus. Bionika i Matem. Modelir. i Biol. Tr. Seminara, Vyp. 1, Kiev, 3-18 THE VELIGER Vol. 14; No. 4 MinicHev, Yu. S. 1969. The structure of the stomach of the opisthobranchiate mollusks (Gastropoda, Opisthobranchia) . ZZ 48 (12): 1780-1787 (ES) Popov, I. E 1969. Submicroscopic organization of connective fibers. Tsitologiya 11 (11): 1379-1386 (ES) SapykKHova, I. A. 1969. | Growth and forms of the shell of the far-eastern mussel (Mytilus grayanus Dunker) in varying conditions of habitat. Trudi Vseso. nauch.-issled. institut morsk. rybn. Khoziaistva i okeanogr. 65: 429-435 SKIRKYAVICHENE, Z. YU. 1970. Regularity of the increase of the weight of Dreissena. 1. The dependence of weight on length. Trudi Lietuvos TSR Mokslu Akad., Vilna. Biol. Inst. DARBAI, (B), No. 1 (51): 71-80 (Lithuanian and English summaries) ZuEv, G. V. 1969. Features of the structure of the mantle of mollusks, the mantle of Symplectoteuthis oualaniensis (Lesson). Biol. Morya., Vyp. 16, Kiev, Nauk. Dumka 102-110 SYSTEMATICS anp FAUNISTICS ANONYMOUS } 1970. A new mollusk in the Black Sea. No. 1: 12 Gav’perina, G. E. 1969. On the identification of the larvae of bivalve mollusks of the northern Caspian Sea. Trudi Molodykh Uchenykh. Vses. nauch.-issled. institut. Morsk rybn. Khoziaistva i okeano- gr., Vyp. 1: 27-41 GupbeTz, V. 1969. On some little known species of mollusks (Pulmonata, Helicidae) . Nauch. doklady vysshei shkoly Biolog. nauki No. 9: 26-34 IocANzEN, B. G. « E. A. Novikov 1969. The fresh-water mollusks of the Basyugan River basin. Uchenye Zapiski Tomskii gosudarstvennogo pedagogich. insti- tuta No. 27: 78-79 IzzaTuuiaEv, Z. 1970. | New species of land mollusks of the genus Pupilla Tur- ton 1831 in Tadzhikistan (Gastropoda, Pulmonata, Pupillidae). Doklady Akad. Fankhon RSS Tochikiston. Dokl. Akad. Nauk. Tadzh SSR 13 (3): 53-55 KaraseEv, N. E 1970. On problems of the study of the aquatic molluscan fau- Vestsi Akad. Nauk Rybn. Koziaistvo na of Berezin governmental preserve. BSSR, Ser. Biol. Nauk 2: 122-123 Maxocon, Ku. G. 1970. Peculiarities of the distribution of the bivalve mollusks of the family Sphaeriidae in the rivers of the southern regions of the Ukraine. Vopr. Rybokhoz. Osvoeniya i San.-biol. rezhima vodosmov Ukrainy. Kiev, Nauk Dumka: 84-86 Mivostavsxkaya, N. M. 1970. | On the absence of Thyasira flexuosa (Montagu) (Un- gulinidae, Bivalvia, Mollusca) in the fauna of the seas of the ZZ 49 (5): 785-786 (ES) extreme north. Vol. 14; No. 4 THE VELIGER Page 439 Rocinsxaya, I. S. 1969. On the taxonomic position and the distribution of Der- matobranchus walteri (Krause, 1892) (Nudibranchia, Armin- idae). ZZ 48 (9): 1320-1324 (ES) SaLManov, E, A. 1969. On the investigation of the terrestrial molluscan fauna of the Talysh and their parasitic helminths. Iz. Akad. Nauk Dumka Azerb SSR, Ser. Biol. Nauk 3: 53-56 Suevtsay, G. A. 1969. Preliminary data on the compositional form of the cephalopod larvae, their distribution and biology: Onycho- teuthis banksi Leach. Izv. Tikho-okeansk. nauch.-issled. instituta rybn. khoziaistva i okeanogr. 68: 186-192 Suixov, E. V. 1970. Land mollusks of the region of Kalinin. Mosk. Univ. Biol., Pochvoved. No. 2: 114-115 STADNICHENKO, A. P. 1969. On the independent identity of Lymnaea corvus Gmelin 1778 and Lymnaea turricula Held 1836. Nauchnye dok- lady vysshei shkoly Biolog. nauki. No. 11: 7-13 Vestnik Srarozocatov, YA. I. 1970. On the relationship of the fresh-water molluscan fauna of Eastern Asia and North America. Sev. Ledovityi Oksan 1 ego pobsrezh’s v Kainozoe, Leningrad. Gidrometeoizdat, 524-544 STJEPCEVIC, JovAN 1969. Cephalopods of Kotorsky Bay. vo 15 (2): 29-71 (Serbian; ES) Poljoprivr. i. Sumarst- BIOLOGY anp ECOLOGY AKIMUSHKIN, I. I. 1970. | Cephalopod mollusks, their distribution and the food web in the nekton. Programma i metoka izuch. biogeo- tsenozov vodn. sredy, Moskva. Nauka: 137-149 ANDREIKEVICH, E. V. 1969. On certain ecological features of the vineyard snail in Latvia. Trudi Lietuvos TSR Mokslu Akad., Vilna. Biol. Inst. DARBAI, (B) No. 3 (50): 63-68 Gtryarov, M. S. 1970. | Modes of dispersal and types of development in fresh- water bivalve mollusks (Bivalvia). ZZ 49 (4): 621-634 (ES) Goroxnoy, V. V. 1969. The ecology of Galba truncatula -— the small pond snail and its epizootic role in varying biotopes. Byul. Vses. Inst. Gel’mintol., Vyp. 3: 21-23 (ES) Ivanov, A. I. 1969. The distribution of mussels, forming the slaked lime for- mation “Kemchug,” in the principal commercial regions of the north-western parts of the Black Sea. Trudy Azovo- Chernomorsk. nauch.-issled. instituta morsk. rybn. Khoziaistva i okeanogr., Vyp. 26: 182-187 Ivanov, A. I. & V. I. PuDENKO 1969. Intensity of feeding in Rapana thomasiana Crosse in re- lation to body size and seasons of the year. Trudy Azovo- Chernomorsk. nauch-issled. instituta morsk. rybn. Khoziaistva i okeanogr., Vyp. 26: 167-172 Kuoxurtkin, I. M. 1969. Materials on the ecology of the live-bearing marsh snail Viviparus contectus (Mill.). Trud. Inst. Ekol. Rast. 1 Zhivotnykh Ural’skii Fil. Akad. Nauk SSSR, Vyp. 71: 125-132 (ES) 1970. | Quantity and biomass of a population of four species of terrestrial mollusks of the genus Bradybaena. Ekologiya, No. 3: 92-94 Konev, A. D. 1970. The thermal stability of the molluscan gastropod genus Littorina in relation to the conditions in the aquatic habitat. Zhur. Obsh. Biol. 31 (3): 337-341 (ES) Mirropov’sku, V. I. 1970. | New data on the feeding of Sphaeriid [clams]. Biol. Vnutr. Vod. Inform. Byul. No. 5: 30-34 Morozov, D. A. 1969. On the biotic considerations for Rapana in saline waters in the Black Sea. Rybn. Khoziaistvo No. 9: 13 Nesis, K. N. 1970. The biology of the Peru-Chilean gigantic squid Dosi- dicus gigas. Okeanolog. 10 (1): 140-152 (ES) Reznik, Z. V. 1970. | Some problems on the ecology of land mollusks of the steppe forests of the Stavropol Heights Fauna Stavropol’ya. Stavropol’ 195-198 SEMENOVA, N. L. 1970. Linear growth of Macoma baltica (L.) in Kandalaksh- sky Bay of the White Sea. Trudi Belomorsk. Biol. St. MGU 3: 69-80 SHapxkarey, I. A. 1969. The distribution and the population density of Dreis- sena polymorpha Pall. (Lamellibranchia) in Macedonian lakes. Godishen. Zbornik, Prirodno-matem. Fak. Univ. Skopje 21: 31-52 (in Macedonian; ES) SKALKIN, V. A. 1970. Distribution of the gastropod mollusk Sulcus discus off the Monneron Islands. ZZ 49 (7): 1084-1085 (ES) TERENT EV, P. V. 1970. The influence of climatic temperature on the size of the shell in terrestrial mollusks. ZZ 49: (1): 5-10 (ES) UvautEva, K. K. 1970. Biological features of the slug pests of cultivated vege- tation in southeastern Kazakhstan. Materialy 2-i Nauchn. Konferentsii Molodykh Uchenykh Akad. Nauk Kaz SSR. Alma- Ata: 395-396 Wituams, S. N. & P. J. HUNTER 1968. Distribution of Bulinus and Biomphalaria in the pro- vinces of Khartoum and Blue Nile, Sudan. BWHO 39 (6): 963-969 ZuURAVEL’, P. A. 1970. On the ecology of the mollusks Fagotia — from the thermal reservoir GRES in the zone of the Dnieprovsky storage lake (Lenin Lake). Vopr. rybkhoz. osvoeniya i san.-biol. rezhima vodosmov Ukrainy, Kiev, Nauk Dumka 74-75 ZuyYvuBIKAS, I. I. 1969. Some data on the biology of Pecten yessoensis Jay in the Kurile-Sakhalin region. Vestnik Leningrad. Universitet., No. 21: 21-32 (ES) Page 440 PHYSIOLOGY ArraPETYAN, S. N., L. F Osrrov « Z. A. SOROKINA 1969. The role of calcium ions in the maintenance of poten- tial chambers and ionic gradients of molluscan neurons. Neirofiziologiya 1 (3): 323-330 (ES) Auimovy, A. F: 1969. Some general properties of the process of filtration in bivalve mollusks. | Zhurnal Obshaia Biol. 30 (5): 621-631 (ES) ALYAKRINSKAYA, I. O. 1970. | Quantitative characteristics of the hemolymph and he- moglobin of the corneus snail Planorbis corneus (Gastropoda, Pulmonata). ZZ 49 (3): 349-353 (ES) Gerasimov, V. D. 1969. The role of small concentrations of sodium ions in the generation of action potentials in the neurons of the vineyard snail (Helix pomatia). Neirofiziologiya 1 (3) : 315-322 (ES) Goromosova, S. A. 1969. | Seasonal dynamics in the chemical composition of Black Sea mussels. Trudy Azovo-Chernomorsk. nauch.-issled. in- stituta morsk. rybn. Khoziaistva i okeanogr., Vyp. 26: 173-181 1970. | Dynamics of the maintenance of poly- and oligo-sac- charides in the fibres of sea mussels. Biol. Morya, Vyp. 18, Kiev, Nauk Dumka: 80-89 Goromosova, S. A. & A. Z. SHAPIRO 1970. On the amylase activity in the hepato-pancreas and muscles of sea mussels [Mytilus]. Biol. Morya, Vyp. 18, Kiev, Nauk Dumka: 89-98 Gricor’Ev, B. F. 1970. Saline stability of the freshwater mollusks of the Dniepr Delta. Vopr. Rybokhoz. osvoeniya i san.-biol. rezhina vodo- emov. Ukrainy. Kiev, Nauk Dumka: 110-112 Gricor’EvA, G. M. 1969. | Cholin-esterase in the optical ganglion of the octopus Ommatostrephes sloanei pacificus. Fermenty i Evolyu- tsii Zhivotnykh. Leningrad Nauka: 177-183 (ES) Karpevicu, A. F « A. T. SHuRIN 1970. The influence of water of various salinities and of man- ganese ions on Macoma baltica L. An elucidation of the forma- tion of manganese concretions. Rybokhoz. Issled. v Basseine Baltiisk. Morya. No. 5, Riga, Zvaigzne 43-59 1970. The influence of physico-chemical conditions on the food of invertebrates and fish of the Baltic Sea and Rizhkiy Bay. Rybokhoz. Issled. v Basseine Baltiisk. Morya No. 6, Riga, Zyaigzne 157-195 Konevy, A. D. 1970. The utilization of a new parameter for exposure to thermal influence prior to the examination of the thermal sta- bility of three species of the genus Littorina. Zhur. Obsh. Biol. 31 (4): 464-468 (ES) Matyuk, V. I. « V. A. Matsxn 1970. _ Peculiarities of the inclusion of radioactive metionin in the gigantic nerve cells of the mollusk Planorbis corneus. Zhur. Evolyuts. Biokhemii i Fiziol. 6 (1): 12-18 (ES) PaTRuUSHEVA, O. I. 1970. Thermal activity of pond life under changing osmotic conditions. Vopr. Evolyutsion. Morfol. i Biogeogr. Kazan’: 67-76 THE VELIGER Vol. 14; No. 4 Rexuina, N. I. 1969. Chemical composition of some species of mollusks in the Barents Sea. Trudi Vseso. nauch.-issled. institut morsk. rybn. Khoziaistva 1 okeanogr. 65: 449-452 Suapiro, A. Z. 1969. Glycolysis in the muscle of the Mytilus galloprovincialis. Fermenti i Evolyutsii Zhivotnykh. Leningrad Nauka: 157-164 (ES) 1970. Features of the process of glycolysis in the muscles of sea mussels. Biol. Morya. Vyp. 18, Kiev, Nauk Dumka 98-113 Suapiro, A. Z. « A. N. BopKova 1970. ‘The influence of copper on several biochemical indices of oxidative exchange within mussels. Vopr. Rybokhoz. osvoeniya i san.-biol. rezhina vodoemov Ukrainy. 1. Kiev, Nauk Dumka 125-126 Sotpatova, I. N. 1970. The reaction of the ciliary epithelium of the bivalve genus Teredo to variations of the salinity of sea water. Tsitologiya 12 (3): 330-337 (ES) STADNICHENKO, A. P. 1970. On the sexual variability of albuminous composition of the blood in Viviparus contectus (Gastropoda, Prosobranchia) . ZZ 49 (5): 680-684 (ES) 1970. | Ontogenetic changes in the albuminous composition of the blood of Lymnaea stagnalis (L.) Gidrobiol. Zhur. 6 (2): 124-127 SuLTANnov, K. M. & Ku. M. ErenpiEev 1969. The distribution of lead in the shells of Recent and fossil pelecypods of the Apsheronsky layer and Recent Caspia. Uchenye Zapiski Azerb. Universitet Ser. Geol.-Geogr. Nauk 3: 29-37 A Taxonomic Note BY A. MYRA KEEN Department of Geology, Stanford University Stanford, California 94305 ARTICLE 23-b oF THE International Code of Zoological Nomenclature, the so-called “Statute of Limitations,” has led to much debate and misunderstanding. Mayr, Simp- son & EISENMANN (1971) cite a new and clarified version of it that is to be published as a new Declaration 2, super- seding the “Declaration 43” published in 1970 in the Bul- letin of Zoological Nomenclature. They dismiss the latter, in a footnote, as illegal, and they imply that it will be with- drawn. They quote the full text of the clarified version, which was accepted in 1969 by more than two-thirds of the International Commission. It is too long to be re- Vol. 14; No. 4 printed here but should be brought to the attention of taxonomists. Several names of Panamic mollusks may require review under this new version, notably: Phlyctiderma discrepans (Carpenter, 1857) versus Diplodonta semirugosa Dall, 1899; Dosinia semiobliterata Deshayes, 1853, versus D. annae Carpenter, 1857; Columbella sonsonatensis (Morch, 1860) versus C. lucasana Dall, 1916; Nassarina cruentata (Mérch, 1860) versus Columbella humerosa Carpenter, 1865; and Volvarina taeniolata Morch, 1860, versus Marginella californica Tomlin, 1916. Under this new version, “A name that is in general current use and has been available for at least 50 years shall not be dis- placed after 1960 by an unused senior synonym.” How- ever, most if not all of these Panamic names may be res- cuable under the further definition of “general current use,” which requires use by “at least five different authors and in at least ten publications.” This provision was de- signed to exclude areas of taxonomy in which there is little activity. Moreover, “use” is qualified as not in- cluding simple mention of a name in a synonymy or mere listing in an index or other nomenclator. Because the literature on West American Mollusca between 1900 and 1960 did not include many monographic or other serious taxonomic reviews, few, if any, of these junior synonyms may qualify as “well-used.” Mayr et al. comment that “there is no reason not to apply strict priority when the junior name is poorly known or has been used only sparingly.” Obviously, this was the conviction of the authors who, since 1960, have brought these “forgotten” names into current usage. However, the wording of the new version of Article 23-b makes clear that such em- ployment of a senior synonym does not cause it to lose its status as a nomen oblitum, and thus technically a peti- tion to the International Commission would still be re- quired to settle the status of these and other specific names. Article 23-b, then, even in amplified form, may continue to prove controversial. Literature Cited Mayr, Ernst, G. G. Simpson & EuGENE EISENMANN 1971. “Stability in zoological nomenclature.” Science 147: 1041 - 1042 (2 December 1971) {Editor’s comment: From our experience with the manu- scripts received, it is evident that the so-called 50-year rule has caused a great deal of confusion and uncertainty, ra- ther than to achieve the goal it was intended to do, namely greater stability. We feel, unhappily, that this new Decla- ration may contribute to further uncertainties and diff- THE VELIGER Page 441 culties. It would seem that all this could be avoided if a return to the absolute priority were accepted. } Generous Donation of the Conchological Club of Southern California After our January issue was already printed, the Concho- logical Club of Southern California made a very generous contribution to the Veliger Endowment Fund. We express our sincere appreciation for this most welcome assistance. As the income only from the Endowment Fund may be used, this contribution from the CCSC will keep on giving and thus assist us in keeping membership dues at a lower figure than would otherwise be necessary. Appointment Dr. J. Wyatt Durham, a member of the Executive Board of the California Malacozoological Society and one of its trustees, as well as a member of the Editorial Board of the Veliger, together with Mr. Joseph H. Peck, Wayne L. Fry and William A. Clemens, Jr. were recently elected co-editors of the Journal of Paleontology. The first number of the Journal under their editorship will be the Septem- ber, 1972 issue. General Notices REGARDING POSTAL SERVICE While increases in postal charges were anticipated, the actual amount involved could not be ascertained until 4 days before the effective date. Thus, we have been un- able to adjust our membership dues and subscription rates to cover these increases. 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We are forced to ask our members and subscribers for reimbursement of these charges; further, because of increased costs in connection with the new mailing plate, we also must ask for reimbursement of that expense. THE VELIGER Vol. 14; No. 4 Effective January 8, 1968 the following charges must be made: change of address — $1.- change of address and re-mailing of a returned issue — $2.-. We must emphasize that these charges cover only our actual expenses and do not include compensation for the extra work involved in re-packing and re-mailing returned copies. Important Notices If the address sheet of this issue is PINK, it is to indicate that your dues remittance had not arrived at the time the mailing was prepared (7. e., by March 1, 1972). We wish to take this opportunity to remind our Members that a reinstatement fee of one dollar becomes due if member- ship renewals have not been received by C.M.S., Inc. by April 15, 1972. Membership renewals are due on or before April 15 each year. 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McGowan] [The two parts are available separately at $3.- each plus a handling charge of $-.75 or as indicated above. If purchased separately, each part is subject to the Califor- nia State sales tax if mailed to California addresses. | Supplement to Volume 7: $2.-* plus $-.60 handling charge [Glossary of A Thousand-and-One Terms used in Conchology, compiled by Winirrep H. Arnoxp] Supplement to Volume 11: $5.-* plus $-.75 handling charge. [The Biology of Acmaea by Prof. D. P. Aszorr et al., ed.] Supplement to Vol. 14: $5.-* plus $-.75 handling charge [The Northwest American Tellinidae by Dr. E. V. Coan] Members in good standing are entitled to one copy at a 20% discount during the current Volume year only. Items marked with * are subject to sales tax in the State of California; residents of that State please add the appropriate amount to their remittances. Prices subject to change without notice. Send orders with remittance to: Mrs. Jean M. Cate, Manager, Post Office Drawer R, Sanibel, Florida 33957. Please make checks payable to C. M. S., Inc. Shipments of material ordered are generally made within two weeks after receipt of remittance. Subscription to Volume 15: $18.- domestic, $19.50 in Canada, Mexico, Central and South America; $20.- in all other foreign countries. THE VELIGER Page 443 Backnumbers of the current volume will be mailed to new subscribers, as well as to those who renew late, on the first working day of the month following receipt of the remittance. The same policy applies to new members. Affiliate Membership for the fiscal year July 1, 1972 to June 30, 1972 has been set at $8.-. Postage for members in Canada, Mexico, Central and South America $1.50, for members in any other foreign country $2.- additional. Effective January 1, 1967 there will be an initiation fee of $2.- for persons joining the Society. Membership open to individuals only - no institutional or society memberships. Please send for membership ap- plication forms to the Manager or the Editor. {We are pleased to announce that we have completed arrangements with Kraus Reprint Co. to reprint those of our publications that are out of print. Inquiries regarding the availability and price(s) of desired items should be addressed to: Kraus Reprint Co. 16 East 46" Street, New York, N. Y. 10017 Regarding UNESCO Coupons We are unable to accept UNESCO coupons in payment, except at a charge of $2.50 (to reimburse us for the ex- penses involved in redeeming them) and at $0.95 per $1.00 face value of the coupons (the amount that we will receive in exchange for the coupons). We regret that these char- ges must be passed on to our correspondents; however, our subscription rates and other charges are so low that we are absolutely unable to absorb additional expenses. Supplements Many of our members desire to receive all supplements published by the Society. Since heretofore we have sent supplements only on separate order, some members have missed the chance of obtaining their copies through over- sight or because of absence from home. It has been sug- gested to us that we should accept “‘standing orders” from individuals to include all supplements published in the future. After careful consideration we have agreed to the proposal. We will accept written requests from individuals to place their names on our list to receive all future sup- plements upon publication; we will enclose our invoice at the same time. The members’ only obligation will be to pay promptly upon receipt of the invoice. Page 444 Requests to be placed on this special mailing list should be sent to the Manager, Mrs. Jean M. Cate, Post Office Drawer R, Sanibel, Florida 33957. CALIFORNIA MALACOZOOLOGICAL SocIETY, Inc. is a non-profit educational corporation (Articles of In- corporation No. 463389 were filed January 6, 1964 in the office of the Secretary of State). The Society publishes a scientific quarterly, the VELIGER. Donations to the Society are used to pay a part of the production costs and thus to keep the subscription rate at a minimum. Donors may designate the Fund to which their contribution is to be credited: Operating Fund (available for current production) ; Savings Fund (available only for specified purposes, such as publication of especially long and signi- ficant papers); Endowment Fund (the income from which is available. The principal is irrevocably dedicated to scientific and educational purposes). Unassigned dona- tions will be used according to greatest need. Contributions to the C. M.S., Inc. are deductible by donors as provided in section 170 of the Internal Revenue Code (for Federal income tax purposes). Bequests, lega- cies, gifts, devices are deductible for Federal estate and gift tax purposes under section 2055, 2106, and 2522 of the Code. The Treasurer of the C. M. S., Inc. will issue suitable receipts which may be used by Donors to substan- tiate their respective tax deductions. Publication Date of THE VELIGER THE PUBLICATION DATE of The Veliger is the date printed on the index page; this applies even if the date falls on a legal holiday or on a Saturday or Sunday, days when the U. S. Post Office does not expedite second class mail matter. That the printed date is the actual date of pub- lication under the rules of the International Commission on Zoological Nomenclature is based on the following 1) The journal is delivered to the Post Office on the first day of each quarter, ready for dispatch; 2) at facts: least three copies are mailed either as first class items or by air mail; 3) about 20 copies are delivered in person to the mail boxes or to the offices of members in the THE VELIGER Vol. 14; No. 4 Berkeley area; 4) two copies are delivered to the re- ceiving department of the General Library of the Univer- sity of California in Berkeley. Thus our publication is available in the meaning of the Code of the ICZN. The printed publication date, therefore, may be relied upon for purposes of establishing priority of new taxa. BOOKS, PERIODICALS, PAMPHLETS Sea Shells of the Texas Coast by Jean AnpreEws. University of Texas Press, Austin, Texas. Pp. 1 - 298; profusely illustrated. $17.50. 1971 A popular account of the shore mollusks of Texas is most appropriate, since none of the existing manuals ade- quately covers this area of biotic transition. Jean Andrews’ delightful book is a veritable vade mecum from which nothing of importance seems to have been left out. It is written in a familiar but tasteful style which cannot fail to hold the attention of the reader. Included is a series of maps with detailed instructions for collecting trips to all parts of the coast, and for what to take along as equip- ment. A vivid account of 400 years of adventurous social history of this area, as well as accounts of the climate, tides, and geologic history, provide shell collectors with greater insight into their activity. There is a chapter on biological classification and nomenclature, very well done, and a good glossary. In the accounts of individual species, vernacular names, as well as the derivation of the scientific binomials are included. More important, and unusual in popular manuals, are the careful citation of author and date of each scientific name, and the source of the original description. Excellent photographs or, in a few cases, drawings of the shells of more than 300 species of mollusks are placed adjacent to the brief but adequate descriptions. There are also numerous artistic photographs of habitats, including the beaches, marshes, oyster beds, jetties and pilings, all done by Jean Bowers Gates and the author. In a chapter on beach combing there are illustrations of many of the other animals, of plants, flotsam and jet- sam, including bottles and Japanese glass floats, which one is likely to encounter. A list is given of the non-marine Vol. 14; No. 4 snails, the shells of which sometimes occur in enormous numbers after heavy inland rains. An extensive bibliography of 250 titles includes general basic works on malacology and other popular treatises on sea shells as well as the more recent technical papers on mollusks and the environment of this area. The book is well edited. The few errors and omissions that I have found are all too trivial to cite. A superb index lists scien- tific and vernacular names of al! organisms, and many other topics discussed. ‘The book is a milestone in the knowledge of the natural history of the Texas coast. It sets a new, higher standard for all future popular works on regional malacology. Jean Andrews has succeeded wonderfully well in catching the mood of a coast poignantly beautiful in its desolation, and she has portrayed its realities with consummate art- istry. H. W. Harry, Texas A and M University Fossil Mollusks of Coastal Oregon by ELLEN James Moore. Oregon State University Press: Oregon State Monographs, Studies in Geology, number 10; pp. 1 - 64; plts. 1-20; 1 table. This useful little handbook is illustrated with photo- graphs of unusual quality. The fauna is that of the Mio- cene Astoria formation. In addition to concise descriptions of the mollusks the collector is apt to find, there are useful notes on the geology of the area, a geologic map, and brief paragraphs on what fossils are, how to collect and identify them, and how to use the literature. The eye-catching cover design is an enlarged photograph of part of a fossil pecten valve. This is a handbook that will fill a long-felt need, and one may hope that similar ones on other Tertiary horizons will follow. MK Shells from Cape Cod to Cape May with special reference to the New York City Area by Morris K. Jacopson & WituiAm K. Emerson. Dover Publications, Inc., New York. Pp. 1 - 152; 166 drawings by Anthony D’Attilio. $2.-; paperbound. 1971 Much of this book was originally published in 1961. How- ever, this is a revised and expanded re-issue. Nomencla- ture has been brought up to date. There are separate chapters dealing with the land snails, mollusks of fresh water, marine gastropods, and marine pelecypods. A sep- arate chapter, entitled “Collecting Shells in Fish Stores” THE VELIGER Page 445 deals with imported species. A series of shell lists for special areas is given. The book is well organized, well written and especially beautifully and accurately illus- trated. While undoubtedly the greatest value of the book is for the shell collectors in the greater New York area and for the venturesome collector from other places, try- ing his luck in New York, it would be of great help to the shell swappers in checking the identifications of the shells received in exchange. The price is certainly modest enough. RS Sea Shells of the World with Values by A. Gorpon MeEtvin. Charles E. Tuttle Company, Rut- land, Vermont. Over 160 pages, about half of which are color plates. $7.50. September 1966 What Scott’s Catalogue is to the stamp collector, this book seems well on the way of becoming for the general shell collector. Prices given for shells are obviously inten- ded as guides. Some people, having heard tales of fabulous prices paid, at one time or another, for a single shell have come to believe that every shell they might pick up at the beach is worth a small fortune. This book can quickly bring them back to the realities of the everyday world. This is not to say that all shells are worth but a penny or two — even though this might be too dear in some cases — but that the expensive shells are the rare ones. ‘The book is well organized and easily used. The illus- trations, in large part colored, are adequate for most pur- poses. This author has commendably refrained from in- venting common names for molluscan species that do not have any, though he does not avoid using really well established ones. RS Florida Marine Shells a guide for collectors of shells of the Southeastern Atlantic Coast and Gulf Coast by C. N. Vitas & N. R. Vitas. Charles E. Tuttle Company, Rutland, Vermont. Pp. 1 - 170; 14 plts., 12 in color. $6.00. New and enlarged edition, June 26, 1970 The first 100 or so pages are devoted to an account of the various species of mollusks that may be found in the area specified in the title. After introductory paragraphs, there follow brief, but adequate descriptions of the species, arranged systematically. The families are briefly charac- terized, followed by a similar characterization of the Page 446 various genera and species. We were delighted to see that the authors not only gave the names of the genera, but also the names of the authors creating them and the year of original description.Similarly, the authors of the species names are also indicated; these, however, without the date. The plates are well executed and we were impressed with the fine quality of the color reproductions, something not too often encountered in the less expensive books. RS A Guide to Shell Collecting in the Kwajalein Atoll by FE B. Brost & R. D. Coa. Charles E. Tuttle Company, Rutland, Vermont. Pp. 1 - 157; 33 “Figures.” $4.95; pub- lished late in 1971, paperback. This book, as its title clearly indicates, is devoted to the molluscan fauna of the Kwajalein Atoll. The authors are modest in calling their illustrations “Figures”, since these are really what are usually called “Plates” with several to many individual figures each; there are a few diagrams in the text that fit the conventional concept of “Figure.” This is not meant to be a criticism, but rather to point out the basic modesty of the authors that comes through in the accounts of the various species. While the book is limited in scope to this particular atoll, it undoubtedly would apply to other atolls in the same general area, except for locality names where the various species occur. ‘This book will be of value to the collector of shells from the Marshall Islands and it should prove also a popular addition to the libraries of many Shell Clubs. RS Pacific Sea Shells by Spencer Witkre Tinker. Charles E. Tuttle Compa- ny, Rutland, Vermont. Pp. 1 - 240; approx. 120 full pages of shell photographs. $3.75; 11" printing, 1970 This work has enjoyed a continuous popularity as evidenced by the fact that the present is the eleventh un- changed printing since the second, revised edition, which was published in 1958. We have compared the present book with that second edition and noted the only differ- ence is the color of the paper on which it is printed. THE VELIGER Vol. 14; No. 4 The earlier printing was on ivory-colored stock, while it is now on white paper; this, in the view of this reviewer, has resulted in an improvement of the quality of the shell pictures. It is quite certain that the latest reprinting will continue to fill the need of shell collectors all over the world, especially those interested in the Hawaiian and Pacific mollusks. The book in 1958 sold for $3.25; the increase to $3.75 over a period of 14 years is certainly astonishingly small. RS The Echo 4 Abstracts and Proceedings of the Fourth Annual Meeting of the Western Society of Malacologists, June 16 - 19, 1971. 86 pp., quarto; illustrated. This publication, distributed to members of the WSM and to subscribers, is also available for purchase (dona- tion) from the Secretary, Mrs. Edith Abbott, 1264 W. Cienega Avenue, San Dimas, California 91773. Publica- tion date is December 27, 1971. In addition to the ‘Minutes’ of the Meetings of the Society and abstracts of the papers presented, this pub- lication also includes several extensive papers. They are: The geologic history of the Muricinae and the Oceneb- rinae by Emily H. Vokes; Muricacean supraspecific taxonomy based on the shell and radula by George E. Radwin « Anthony D’Attilio. The publication is well edited, well printed, and beauti- fully illustrated. RS Development of Shellfish Culture Techniques by Victor L. Loosanorr. in Proc. of Conference on arti- ficial propagation of commercially valuable shellfish — Oysters — held at College of Marine Studies, Univ. Dela- ware, Newark, Delaware Oct. 22 - 23, 1969; pp. 9 - 40 This critical review in a masterly fashion outlines various methods of artificial rearing of molluscan larvae and gives sound appraisals of them. The information presented is in a very concise form and the article is must-reading for all mariculturists. RS THE VELIGER is open to original papers pertaining to any problem concerned with mollusks. This is meant to make facilities available for publication of original articles from a wide field of endeavor. Papers dealing with anatomical, cytological, distri- butional, ecological, histological, morphological, physiological, taxonomic, etc., aspects of marine, freshwater or terrestrial mollusks from any region, will be considered. Even topics only indirectly concerned with mollusks may be acceptable. It is the editorial policy to preserve the individualistic writing style of the author; therefore any editorial changes in a manuscript will be submitted to the author for his approval, before going to press. Short articles containing descriptions of new species or other taxa will be given preferential treatment in the speed of publication provided that arrangements have been made by the author for depositing the holotype with a recognized public Museum. Museum numbers of the type specimens must be included in the manuscript. Type localities must be defined as accurately as possible, with geo- graphical longitudes and latitudes added. Short original papers, not exceeding 500 words, may be published in the column “NOTES and NEWS”; in this column will also appear notices of meetings of regional, national and international malacological organizations, such as A. M.U., U. M. E., W.S.M., etc., as well as news items which are deemed of interest to our Members and subscribers in general. Articles on “METHODS and TECH- NIQUES” will be considered for publication in another column, provided that the information is complete and techniques and methods are capable of duplication by anyone carefully following the description given. Such articles should be mainly original and deal with collecting, preparing, maintaining, studying, photographing, etc., of mollusks or other invertebrates. A third column, entitled “INFORMA- TION DESK,” will contain articles dealing with any problem pertaining to collecting, identifying, etc., in short, problems encountered by our readers. In contrast to other contributions, articles in this column do not necessarily contain new and original materials. Questions to the editor, which can be answered in this column, are invited. The column “BOOKS, PERIODICALS, and PAMPHLETS” will attempt to bring reviews of new publications to the attention of our readers. Also, new timely articles may be listed by title only, if this is deemed expedient. Manuscripts should be typed in final form on a high grade white paper, not exceeding 81,” by 11”, at least double spaced and accompanied by a clear carbon or photo copy. A pamphlet with detailed suggestions for preparing manuscripts intended for publication in THE VELIGER is available to authors upon request. A self-addressed envelope, sufficiently large to accommodate the pamphlet (which measures 5,” by 81”), with double first class postage, should be sent with the request to the Editor. EDITORIAL BOARD Dr. Donatp P. Asgort, Professor of Biology Hopkins Marine Station of Stanford University Dr. Jerry DonouueE, Professor of Chemistry University of Pennsylvania, Philadelphia, and Research Associate in the Allan Hancock Foundation University of Southern California, Los Angeles Dr. J. Wyatr Duruam, Professor of Paleontology University of California, Berkeley, California Dr. E. W. Facer, Professor of Biology Scripps Institution of Oceanography, La Jolla University of California at San Diego Dr. Caner Hanp, Professor of Zoology and Director, Bodega Marine Laboratory University of California, Berkeley, California Dr. Jort W. HepcretH, Resident Director Marine Science Laboratory, Oregon State University Newport, Oregon Dr. LEo G. HERTLEIN, Curator of Invertebrate Paleontology, Emeritus California Academy of Sciences, San Francisco Dr. A. Myra KEeEn, Professor of Paleontology and Curator of Malacology, Emeritus Stanford University, Stanford, California Dr. Victor Loosanorr, Professor of Marine Biology Pacific Marine Station of the University of the Pacific Dr. Joun McGowan, Associate Professor of Oceanography Scripps Institution of Oceanography, La Jolla University of California at San Diego Dr. Frank A. PirELKa, Professor of Zoology University of California, Berkeley, California Dr. Rosert Rosertson, Chairman and Pilsbry Chair of Malacology, Department of Malacology Academy of Natural Sciences of Philadelphia Mr. Attyn G. SmitH, Associate Curator Department of Invertebrate Zoology California Academy of Sciences, San Francisco Dr. Ratpu I. Smiru, Professor of Zoology University of California, Berkeley, California Dr. CuHar.es R. STAsEk, Associate Professor of Zoology Florida State University, Tallahassee, Florida EDITOR-IN-CHIEF Dr. Rupotr SToH er, Research Zoologist, Emeritus University of California, Berkeley, California ASSOCIATE EDITOR Mrs. Jean M. 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