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SMITHSONIAN NVINOSHLIWS NOILALILSNI LIBRARIES SMITHSONIAN ee SB RAR LES 17 LIBRARIES YN iV % +. iad Ia Xi riba eas . Vol. 21; No. 1 THE VELIGER Page 15 the sea star Asterias amurensis Ives, 1891, was found to yield carotenoids upon denaturation (YosHmA & OHTSU- KI, 1966) which suggests that carotenoids may be the shading pigments of red ocelli. Electron dense granules of shading pigment, thought to be melanin (Eakin, 1972), are more common among invertebrates than are these red granules. The cilia found in the mussel retina have the form of 9+2 kinocilia with arms rather than of 9 +0 sensory cilia. Numerous other ocelli with rhabdomeric photoreceptors also possess 9+2 cilia that may originate from sensory cells, pigment cells, or both (EaK1n et al., 1967; Tono- SAKI, 1967; HuGHEs, 1970; JACKLET et al., 1972; MAYES & HERMANS, 1973; BoyLe, 1969; BAKER, 1975). Cilia in the retina of Mytilus possibly serve a cleansing function, such as preventing mucus laden with debris from fouling the rhabdomeres. These cilia are not regarded as photo- sensitive structures, and further research is needed before these cilia can be considered as the inducers of photore- ceptor formation (VANFLETEREN & COOMANS, 1976). Unusual accumulations of smooth endoplasmic reticu- lum found in the nuclear regions of the sensory cells (Fig- ure 5) are similar in form to the smooth endoplasmic reticulum found in the eye of the garden slug Limax maxi- mus Linnaeus, 1758 (EAKIN & BRANDENBURGER, 1975). In Limax, however, this membranous organelle has al- ways been observed in the distal ends of sensory cells in several separate formations rather than in one large accu- mulation as in Mytilus. EAKIN & BRANDENBURGER (op. cit.) cited several other instances in which this special endoplasmic reticulum has been described. Its occurrence is not restricted to eyes. At the time of their publication, Eakin & BRANDENBURGER (of. cit.) were attempting to link this special endoplasmic reticulum to calcium trans- port, but conclusive evidence was not obtained. In Mytilus, it is likely that this special endoplasmic reticulum serves as a synthesizing organelle; however, further research is needed to determine its function. The membrane-bounded cytoplasmic vesicles observed in the sensory cells are similar to the spherical vesicles in other molluscan photosensory cells described by EAKIN et al. (1967), Tonosaxi (1967), HucHEs (1970), Mayes & HERMANS (1973), and BAKER (1975). The eyes of the pulmonates described by EaKIN & BRANDENBURGER (1967a, 1975) contain sensory cell vesicles that are organ- ized into paracrystalline arrays and have been termed photic vesicles by those authors. Photic vesicles carry photopigment, or precursors thereof, from Golgi bodies, from which they originate, to the bases of the microvilli (EakIn & BRANDENBURGER, 1967b, 1974). The presence and arrangement of cytoplasmic vesicles in Mytilus and other molluscan eyes suggest similar functions. Behavioral Role Young, eyed, veliger larvae of Mytilus display positive phototaxis. Older, pediveliger larvae are negatively photo- tactic and settle with the anterior end oriented away from light (BAYNE, 1964). In larval mussels, it is possible that the cerebral eyes provide the directional sensitivity to light. In an attempt to relate the presence of eyes to the biology of Mytilus, simple field and laboratory observa- tions of post-larval mussels have revealed no behavioral responses indicative of light sensitivity. In the field, the direction of illumination, or the absence of direct illumi- nation does not obviously affect the orientation of indi- viduals, pattern of clumping, distribution of clumps, or filter-feeding activities. Simulated predation by shadow- casting, or sudden intense illumination directed upon the shell windows did not stop the pumping activity of gaping mussels, whereas even slight tactile stimulation applied with the blunt end of an applicator stick to the exposed mantle tissues or shell, resulted in the closure of gaping mussels. Harcer (1968) reported another instance in which other senses predominate over that of light sensitivity in mussels. That author described a “crawling out” behavior in Mytilus edulis but not in M.californianus Conrad, 1837, the sea mussel. Where both species occurred together on pier piles, 4. edulis was more prominent on the outside of clumps. Under laboratory conditions, M. edulis con- sistently “crawled out” from under 5cm of pea-sized grav- el whereas M. californianus did not. Neither the direction of illumination, nor the absence of it, affected this re- sponse. HarGER (op. cit.) considered “crawling out” be- havior an adaptation that prevents bay mussels from becoming smothered by silt, which is not a problem for sea mussels exposed to wave action. Although no correlation between the presence of the ocelli and photic response could be made, 3 anatomical features suggest that the eyes remain functional in post- larval mussels. First, the overall structure of the ocellus is that of a photosensitive organ. Next, the presence of axons and synthesizing organelles indicates that the ocel- lus is engaged in sensory activity. Finally, the “shell win- dow” allows the eye to receive illumination. PELSENEER (1908) stated that several of the 30 species he studied possess a triangular translucent zone in the anterior region of each valve and suggested that this allows the eyes to remain functional. An example of functional light trans- mission through a molluscan shell has been described recently. LinpBERc et al. (1975) demonstrated that the nocturnal limpet Notoacmea persona (Rathke, 1833) is negatively phototactic, a behavior mediated by light strik- Page 16 ing the eyes through translucent zones in the anterior region of the shell. In addition to the “shell windows,” PELSENEER (1908) observed conditions among the cerebral eyes of bivalves that indicate that these eyes are only present when they can be functional, that is, in the presence of light. Pzncta- da and Anomia bear larvae with paired cerebral eyes. As these bivalves mature, they become fixed to the bottom with the right side adjacent to the substratum, and the eye on that unilluminated side subsequently atrophies whereas the eye on the illuminated side persists. Species of Dacrydium, of the family Mytilidae, live in the aphotic zone and are without eyes. Modiolaria trapezina Lamarck, 1819, also a mytilid, has larvae that are incubated within the mantle cavities of the adults, and this species lacks eyes throughout its life history. Apparently, natural selec- tion conserves cerebral eyes only when they are of some functional value. What, then, is the function of these ocelli? The lack of immediate behavioral responses to light suggests that the eyes in post-larval mussels may function in some long term response, such as mediating photoperiod in the re- productive cycle. This hypothesis may find support in the work by Etvin (1976), who demonstrated that neuro- secretory release by the cerebral ganglia in sexually ma- ture specimens of Mytilus edulis is enhanced by the presence of light. Evolutionary Significance A. Homology of Molluscan Cerebral Eyes The cerebral eyes of bivalves and the larval eyes of chitons develop in the region immediately posterior to the proto- troch (PELSENEER, 1908; HEATH, 1904). Because of their location, these eyes have not been considered homo- logous to the pre-trochal cerebral eyes of the Gastropoda, or to the cephalic eyes of the Cephalopoda, which are without a larval stage (PELSENEER, 1908; RavEN, 1966). There are, however, structural similarities among the THE VELIGER Vol. 21; No. 1 ocelli of bivalves, gastropods, and cephalopods that indi- cate that the prototroch may be of secondary importance with respect to ocellar homologies. Ultrastructural in- vestigations to date have demonstrated that molluscan cerebral eyes have similar retinas composed of interdig- itating pigment and sensory cells with microvillous rhab- domeres borne at the distal ends of sensory cells. Addi- tionally, the cerebral ganglia of these classes develop from similar cephalic plates (RAVEN, 1966), and innervation of the cerebral eyes is directly from the cerebral ganglia whether the eyes develop in the pre- or post-trochal region (FIELD, 1922; RaveEN, op. cit.). These character- istics indicate that the cerebral eyes of the bivalves are homologous to those of the gastropods and cephalopods. The larval eyes in chitons have been considered by PELSENEER (1899) as likely to be homologous to the cereb- ral eyes of bivalves, on the basis of their similar, post- trochal locations. HEATH (1904), however, stated that these two groups of ocelli are fundamentally different in structure and noted that the innervation of the chiton ocellus is from the pallial nerves. Thus, an ultrastructural description of the larval eyes in chitons would be useful in determining whether these eyes are similar to the cereb- ral eyes of the other molluscan classes, and is now in prog- ress '. PELSENEER (1908) stated that he labeled cerebral eyes as “cephalic eyes” in 1899 to distinguish them from pallial eyes, even though he did not consider the former to be homologous with the eyes of cephalopods and gastropods. Also in 1908, Pelseneer changed his term for these eyes from “yeux cephaliques” to “yeux branchiaux.” Appar- ently, Pelseneer made this change in terminology to main- ' Note added in proof: One of us (M.D. R.) has begun prelim- inary observations on the ultrastructure of ocelli in, the larvae of Katharina tunicata, obtained through the courtesy of Dr. Dale B. Bonar at Friday Harbor Laboratories, Summer of 1977. The ocellus consists of several pigment cells and at least one sensory cell. The presumptive photoreceptors are rhabdomeric micro- villi that originate at the distal end of the sensory cell. Explanation of Figures 10 to 13 Figure 10: Three adjacent pigment cell apices. Arrows indicate origins of microvilli (MV). Dense cytoplasm (DC) is occasionally observed at pigment cell apices. tate junction; CV — cytoplasmic vesicles Z — adhering zonule; SJ — sep- X 29 000 Figure 11: Sensory cell apex. Arrows indicate origins of microvilli (MV). A cilium (C) may be originating from this cell. Z — ad- hering zonule; SJ — septate junction; CV - cytoplasmic vesicles X 29 000 Figure 12: Photoreceptoral microvilli (MV) and cilia (C) in the ocellar cavity X 10000 Figure 13: Microvilli (MV) and sensory cell cilia (C) in cross section X 38 000 THE VELIGER, Vol. 21, No. 1 [RosEN, STASEK & HERMANS] Figures 10 to 13 ~ Th é r * : rn 9 ; : ,' bY ae oR bite 6 j ? Me ay i Page Mo: a ae c. £9 5: Wh) 7 i 2 7 4 o Ty Z, : aot " > A .' we ~ Fas a CK ~ 2 ae he *CNy, 2 > Sen, F2 >. — x be “ ; a ° . - we Vol. 21; No. 1 THE VELIGER Page 17 tain the continuity of his phylogenetic scheme in which modern families of bivalves were conceived to have evolved from one another on the basis of increasing com- plexity of their gills (see family tree in PELSENEER, 1911: 123). His stated reasons for this revision were 1) the eyes are situated on the branchial filaments, and 2) the Recent nuculid protobranchs, considered by Pelseneer to be the ancestral bivalves, lack these eyes in all stages of development. Hence, he concluded that the cerebral eyes in mytilids could not have been inherited from these proto- branchs and must therefore be recently evolved speciali- zations. Our re-interpretation is as follows: 1) The eyes are found on the first branchial filaments of post-larval mussels (Figure 6) but originate in the larvae prior to the formation of these filaments; 2) the gills are innervated by the visceral ganglia (FIELD, 1922), indicating that the eyes, which have cerebral innervation, are not funda- mentally branchial; 3) although the protobranchs are considered primitive on the basis of gill type by PELSE- NEER (1911) and gill to palp association by STASEK (1963), their lack of eyes does not necessarily reflect a primitive condition, but rather a secondary loss since all modern species occupy deep-water or infaunal habitats where cerebral ocelli would have no functional role. B. Ciliary Photoreceptors versus Rhabdomeric Photoreceptors All the eyes of bivalves previously studied by electron microscopy have contained photoreceptoral organelles that are derived from modified cilia (BARBER et al., 1967; BarBER & LAND, 1967; BARBER & WRIGHT, 1969a; Kawa- cuT1 « Masucui, 1969; Levi & Levi, 1971; ADAL & Morton, 1973). The photoreceptors of these eyes have therefore presented exceptions to Eakin’s postulation that rhabdomeric photoreceptors are typical of the pro- tostomous phyla (Eakin, 1968). However, there is no evidence that pallial eyes are homologous with cerebral eyes. Therefore, the occurrence of ciliary photoreceptors within pallial ocelli is here regarded as immaterial to the present evolutionary hypotheses concerning cerebral ocelli. Rather, the cerebral ocelli of Mytzlus contain rhabdo- meric photoreceptors, as well as other ultrastructural features that conform to the structural patterns found in the cerebral ocelli of hitherto studied species of mollusks, sipunculans, annelids, and onychophorans, as noted by HeErMaANS (1969), HERMANS & EakIN (1974), and Er- MAK & EaKIN (1975). Thus, judged from the groups examined to date, photoreceptor type is conserved in cerebral ocelli and does aid in establishing the broad evolutionary affinities among the protostomous phyla. The cerebral eye of the heteropod Pterotrachea mutica, as described by Ditty (1969), may represent an excep- tion to the apparent conservatism in the structure of photoreceptors in the cerebral ocelli of the protostomes. Dilly considered the photoreceptors of this eye to be of the ciliary type, but his evidence is not convincing (see EaKIN, 1972: 629 - 630). C. Evolution and Function Lanp (1968) concluded from behavioral and electro- physiological data that eyes with ciliary photoreceptors typically respond to cessation of illumination or to shadows and usually function in protection from predatory attack. In contrast, eyes with rhabdomeric photoreceptors typi- cally respond to the onset of illumination and function by monitoring light intensity. VANFLETEREN & COOMANS (1976) considered this correlation between photoreceptor type and ocellar function as a generalization with a few known exceptions. Moreover, we regard this pattern as a potential explanation for the selective pressures that may have led to the presence of either ciliary or rhabdomeric photoreceptors in non-cerebral ocelli. CONCLUSION The cerebral ocelli of Mytilus edulis bear rhabdomeric photoreceptors and conform in this way to the cerebral ocelli of all other protostomous classes hitherto described. The diversity in structure and location of non-cerebral ocelli indicates that as a group they are not homologous sense organs. Yet, the similarities among certain groups of ocelli, such as the branchial eyes of sabellid polychaetes, may be useful in studying relationships at low taxonomic levels, as suggested by VANFLETEREN & COOMANS (1976). On the other hand, we are suggesting that the cerebral ocelli of the protostomes are all homologous and are use- ful for studying relationships at high taxonomic levels. Literature Cited Apa, M. N. « Brian Morton 1973- The fine structure of the pallial eyes of Laternula truncata (Bi- valvia : Anomelodesmata : Pandoracea) Journ. Zool. 170 (4): 553-556; 3 text figs.; 12 plts. Baxer, Marcaret Mayes 1975. A light and electron microscopic study of the eyes of four proso- branch mollusks, Littorina littorea, Nucella emarginata, Lacuna Spp., and Tegula funebralis. M. A. thesis, Biol. Dept., Sonoma State College; 72 pp.; 22 plts. Barser, V. C., E1reen Evans a M. FE Lanp 1967. The fine structure of the eye of the mollusc Pecten maximus. Zeitschr. Zellforsch. 76: 295 - 312; 13 figs. Barser, V. C. & M. FE Lanp 1967. The eye of the cockle, Cardium edule: anatomy and physiologi- cal investigation. Experientia 23: 677 - 678; 3 figs. Page 18 THE VELIGER Vol. 21; No. 1 Barser, V. C. « D. E. Wricut 1969a. The fine structure of the eye and optic tentacle of the mollusc Cardium edule. Journ. Ultrastruct. Res. 26: 515-528; 12 figs. 1969b. The fine structure of the sense organs of the cephalopod mollusc Nautilus. Zeitschr. Zellforsch. 102: 293 - 312; 23 figs. BayNeE, Brian LEICESTER 1964. The responses of the larvae of Mytilus edulis L. to light and to gravity. Oikos 15: 162-174; 4 figs.; 1 table Bayne, Brian Leicester, J. Wmpows & R. J. THomPsoNn 1976. Physiology II. Pp. 207 - 260; 18 figs. in: B. L. Baine (ed.), Marine mussels: their ecology and physiology, Chapter 6. Cambridge Univ. Press, New York Boye, Peter R. 1969. Fine structure of the eyes of Ontthochiton neglectus (Mollusca: Polyplacophora). Zeitschr. Zellforsch. 102: 313 - 3323 23 figs. Ditry, P Noe 1969. The structure of a photoreceptor organelle in the eye of Ptero- trachea mutica. Zeitschr. Zellforsch. 99: 420 - 429; 9 figs. Eaxin, RicHarD MARSHALL 1963. Lines of evolution of photoreceptors. PP. 393-425; 38 figs. in: D. Mazia & A. Tyler (eds.), General physiology of cell specialization, chapt. 21. McGraw-Hill, New York 1965. Evolution of photoreceptors. pp. 363-370; 3 figs. in: Cold Spring Harbor Symposia on quantitative biology, vol. 30. Cold Spring Harbor. Labor. Quantitat. Biol. Cold Spring Harbor, Long Is- land, New York 1968. Evolution of photoreceptors. PP. 194-242; 24 figs. in: Th. Dobzhansky, M. K. Hecht « Wm. C. Steere (eds.), Evolutionary bio- logy, vol. 2, chapt. 5. | Appleton-Century-Crofts, New York 1972. Structure of invertebrate photoreceptors. pp. 623 - 684; 59 figs. in: H. J. Dartnall (ed.), Handbook of sensory physiology, vol. 7, chapt. 16. Springer Verlag, Berlin, Heidelberg, New York Eakin, RicHARD MARSHALL & JEAN LEUTWILER BRANDENBURGER 1967a. Differentiation in the eye of a pulmonate snail, Helix asper- Sa. Journ. Ultrastruct. Res. 18: 391 - 421; 28 figs. 1967b. Functional significance of small vesicles in the photoreceptor cells of a snail, Helix aspersa. Journ. Cell Biol. 35: 36A 1974. Ultrastructural effects of dark adaptation on the eyes of a snail, Helix aspersa. Journ. Exp. Zool. 187 (1): 127-133; 6 figs. (January 1974) 1975. Retinal differences in light tolerant and light avoiding slugs (Mollusca: Pulmonata). Journ. Ultrastruct. Res. 53: 382 - 394; 15 figs. Eaxin, RicHarp MarsHALL, JANE WesTFALL & M. J. Dennis 1967. Fine structure of the eye of a nudibranch mollusc, Hermissenda crassicornis. Ervin, Davin W. 1976. Observations on the effects of light and temperature on the ap- parent neurosecretory cells of Mytilus edulis. Biol. Bull. 151 (2): 408 Ermaxk, THomas H. & RicHarp MARSHALL EAKIN 1975. Fine structure of the cerebral and pygidial ocelli in Chone eu- caudata (Polychaeta: Sabellidae). Journ. Ultrastruct. Res. 54: 243 - 260; 22 figs. Fizvp, Irvine A. 1922. Biology and economic value of the sea mussel Mytilus edulis. Bull. U. S. Bur. Fish. 38: 127 - 259; 230 figs. Haroer, Joun Rosin 1968. The role of behavioral traits in influencing the distribution of two species of sea mussel, Mytilus edulis and Mytilus californianus. The Veliger 11 (1): 45-49; 3 text figs. (1 July 1968) Heatu, Haroip 1904. The larval eye of chitons. 56: 257-259; 3 figs. Hermans, Coin O. 1969. Fine structure of the segmental ocelli of Armandia brevis (Poly- chaeta: Opheliidae). Zeitschr. Zellforsch. 96: 361 - 371; 6 figs. Journ. Cell Sci. 2 (3): 349-358; 11 figs. Proc. Acad. Nat. Sci. Philadelphia Hermans, Couin O. & RicHARD MarRSHALL EAKIN 1974. Fine structure of the eyes of an alciopid polychaete, Vanadis tagensis (Annelida). Zeitschr. Morphol. Tiere 79: 245 - 267; 17 figs. Hucues, Hexen P I. 1970. A light and electron microscopic study of some opisthobranch eyes. Zeitschr. Zellforsch. 106: 78 - 98; 23 figs. JAcKLET, Jon Wits, RENATE ALVAREZ & BARBARA BERNSTEIN 1972. Ultrastructure of the eye of Aplysia. Journ. Ultrastruct. Res. 38: 246 - 261; 15 figs. KawacutT1, Siro & KatsHipE MasucHi 1969. Electron microscopy of the eyes of the giant clam. Biol. Journ. Okayama Univ. 15: (3/4): 87-100; 20 figs. Lanp, M. FE 1968. Functional aspects of the optical and retinal organization of the mollusc eye. Symp. Zool. Soc. London 23: 75 - 96; 5 figs. Levi, PrERRETTE & CLAUDE LEvi 1971. Ultrastructure des yeux palleux d’ Arca noe. scopie II: 425 - 432; 4 plts. Linpserc, Davip R., MicHazt G. Kettocc « Wayne E. HucHEes 1975- Evidence of light reception through the shell of Notoacmea per- sona. The Veliger 17 (4): 383 - 386; 1 plt.; 4 text figs. (1 April 1975) Journ. micro- Mayes, Marcaret & CoLin O. HERMANS 1973. The fine structure of the eye of the prosobranch mollusk Lit- torina scutulata. The Veliger 16 (2): 166-169; 5 plts. (1 October 1973) PELSENEER, PAUL 1899. Les yeux céphaliques chez les Jamellibranches. Arch. Biol. Liége 16: 97 - 103; 8 figs. 1908. Les yeux branchiaux des Jamellibranches. Bull. Acad. Roy. Belg. (Classe Sci.) 1908: 773 - 779 1911. _ Les lamellibranches de l’expédition du Siboga. Partie anatomique. Siboga Exped. 53a: 1 - 125 Raven, CHRISTIAN PIETER 1966. Morphogenesis: The analysis of molluscan development. 2nd ed., Pergamon Press, Oxford, xiiit+365 pp.; 12 plts.; 66 text figs. STAsEK, CHARLES ROBERT 1963. Synopsis and discussion of the association of ctenidia and labial palps in the bivalved Mollusca. The Veliger 6 (2): 91-97; 5 text figs. (1 October 1963) ToNoSAKI, AKIRA 1965. The fine structure of the retinal plexus in Octopus vulgaris. Zeitschr. Zellforsch. 67: 521 - 532; 12 figs. 1967. The fine structure of the retina of Haliotis discus. Zellforsch. 79: 469 - 480; 13 figs. VANFLETEREN, J. R. 2 A. CoomANns 1976. Photoreceptor evolution and phylogeny. Evolutionsforsch. 14: 157-169; 5 figs. VaAuUPEL-von Harnack, M. 1963. Uber den Feinbau des Nervensystems des Seesterns (Asterias rubens L.). III. Mitteilung: die Struktur der Augenpolster. Zeit- schr. Zellforsch. 60: 432 - 452; 18 figs. WoLKEN, JEROME J. 1967. Euglena: an experimental organism for biochemical and bio- physical studies. and ed., Appleton-Century-Crofts, New York, xii+ 204 pp.; 88 figs. Zeitschr. Zeitschr. Zool. Syst. 1971. Invertebrate photoreceptors. Acad. Press, New York & Lon- don, xi+179 pp.; 117 figs.; 2 tables 1974. Comparative structure of invertebrate photoreceptors. pp- 111-154, 19 figs.; 1 table, in: H. Davidson « L. T. Grahm (eds.) The Eye, vol. 6, chapt. 2, Acad. Press, New York & London Yosuma, M. «a H. OntsuKI 1966. Compound ocellus of a starfish: its function. 197-198; 1 fig. Zonana, Howarp V. 1961. +-Fine structure of the squid retina. Hosp. 109: 185 - 205; 14 figs. Science 153: Bull. Johns Hopkins Vol. 21; No. 1 THE VELIGER Page 19 The Genus Lepidozona (Mollusca : Polyplacophora ) in the Temperate Eastern Pacific, Baja California to Alaska, with the Description of a New Species ANTONIO J. FERREIRA ' Research Associate, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118 (5 Plates; 3 Text figures) THE GENus Lepidozona Pilsbry, 1892, is remarkably well represented in the eastern Pacific. In addition to the 6 species recognized in the Panamic province (FERREIRA, 1974), some twenty other nominal species of chitons in the northeastern Pacific have been assigned to the genus. This study continues previous work on the tropical eastern Pacific Lepidozona (FERREIRA, /.c.), and extends the review of the genus to the temperate waters of the Californian, Oregonian, and Aleutian provinces which, covering some 6000km of coast from Baja California to Alaska, lie between the parallels 23°N and 60°N approx- imately. The investigation is based upon the examination of material in the collections of the California Academy of Sciences (CAS), Los Angeles County Museum of Nat- ural History (LACM), Allan Hancock Foundation (AHF), University of Southern California (UCLA), San Diego Museum of Natural History (SDNH), United States National Museum of Natural History (USNM), Academy of Natural Sciences of Philadelphia (ANSP), and in the private collections of Allyn G. Smith (AGS), John H. Himmelman, S. Stillman Berry (SSB), Salle Crittenden, George A. Hanselman, Glenn & Laura Burg- hardt, and myself (AJF). From the data, 8 species of Lepidozona are recognized in the temperate northeastern Pacific, one new to science: Leptdozona cooper (Dall, 1879) Lepidozona guadalupensis Ferreira, spec. nov. Lepidozona mertensit (Middendorff, 1847) ' Mailing address for reprints: 2060 Clarmar Way, San Jose, CA(lifornia) 95128, U.S. A. Lepidozona pectinulata (Carpenter in Pilsbry, 1893) Lepidozona retiporosa (Carpenter, 1864) Lepidozona scabricostata (Carpenter, 1864) Lepidozona sinudentata (Carpenter tn Pilsbry, 1892) Lepidozona willetti (Berry, 1917) POLYPLACOPHORA de Blainville, 1816 Neoloricata Bergenhayn, 1955 ISCHNOCHITONINA Bergenhayn, 1930 IscHNOCHITONDAE Dall, 1889 Lepidozona Pilsbry, 1892 As redescribed (FERREIRA, 1974: 163): Small to medium size chitons. End valves and lateral areas with radial ribs, usually pustulose or graniferous; central areas with lon- gitudinal riblets, often cross-ribbed (latticed), the jugal tract usually diverging forwardly to form a wedge-like feature on the second valve. Articulamentum usually white; end valves with around 10 slits; intermediate valves uni-slitted; sutural laminae sharp; eaves not spongy; sinus well defined. Girdle of imbricated, medium size scales, usually strongly convex, striated, and mammillated. Type species: Chiton mertensti Middendorff, 1847, by OD, Pitssry, 1892: 125. Page 20 Lepidozona mertensii (Middendorff, 1847) (Figures 1, 2, 20, 27, 34) Chiton Mertensti MiDDENDORFF, 1847a: 118 Chiton (Stenosemus) Mertenstt, MIDDENDORFF, 1847b: 125 - 127, tbl. 14, figs. 1-3 Lepidopleurus mertensit, Cooper, 1867: 22 — Dati, 1879: 332 Ischnochiton mertensit, P1tsBry, 1892; 125 - 126, plt. 26, figs. 20 - 26, (in section Lepidozona); 1898, 50: 288 — HEATH, 1904, 56: 257-259, textfig. B; 1905, 29: 391 — NIER- STRASZ, 1905, 48: 82 — BERRY, 1907, 21 (5): 51 — DALL, 1921, 112: 192 (in section Lepidozona) — OLproyp, 1924: 191-192; 1927: 280-281 — JOHNSON & SNOOK, 1927: 564 — S1IMROTH & HOFFMAN, 1929: 314 —- CHACE & CHACE, 1930, 44(1): 8; 1933, 46(4): 124 — FRASER, 1932, 3rd ser., 26(5): 65 — LeLoup, 1940: 10- 12, figs. 25-33 — WILLETT, 1941: 185-186, fig. 1 —- ANDREWS, 1945, 26: 24-37 — La RocqQue, 1953: 12 (in section Lepidozona) — Licut, et al., end ed., 1954: 217-218 — THOMPSON & CHOw, 1955, 3 (suppl.): 20-39 — THORPE, 1962, 4 (4): 205, 207 — HELFMAN, 1968, 10 (3): 290- 291 Ischnochiton (Lepidozona) mertensit, BERRY, 1917, 7 (10): 26; 1922, 11(18): 475-476, plt. 10, figs. 7-12 (fossil); 1927, 17: 164 — A. G. Smitn, 1947: 18 — A. G. SMITH & Gorpon, 1948, 26 (8): 208 — ABBOTT, 1954: 322 - 323 Leptdozona mertensit, Is. Taki, 1938: 390 - 392, plt. 14, fig. 6; plt. 20, figs. 1-6; plt. 30, figs. 6-9; plt. 31, figs. 9, 10; 1962: 41 — RickETTs & CaLvin, 1962: 89, and frontis- piece (in color) — Iw. Taki, 1964: 409 — BURGHARDT & BurcuHarnT, 1969: 22, plt. 2, fig. 28 (in color) — Rice, 1971: 20, plt. 4, fig. 9 (in color) — A. G. SmiTH tn Licut, et al., 3rd ed., 1974: 463, 465 — AxBsBotTr, 1974: 395, fig. 4639 Diagnosis: Chitons of medium size (up to about 4cm); color in reddish tones, uniformly, speckled, or with one or two transversal bands of a cream color. End valves and lateral areas with radial rows of robust tubercles defining virtual ‘‘ribs’”’ not separated by sulci; central areas with longitudinal riblets cross-ribbed for a latticed effect. Gir- dle scales convex, often mammillated, obsoletely striated. Type Material: Lost, or never designated. OLDRoYD (1927: 281) stated “Type in Academy, St. Petersburg’; but an inquiry to the Academy of Sciences of the USSR, Leningrad, revealed that ““Middendorff’s specimens are absent in the Academy collection” (Dr. B. Sirenko, in litt., THE VELIGER Vol. 21; No. 1 November 12, 1975). Since Middendorff’s original speci- mens cannot be located, a neotype specimen from the orig- inal locality, Fort Ross, California, is designated, de- scribed, and illustrated, in accordance with Article 75 of the International Code of Zoological Nomenclature (ICZN), London, 1964. The neotype is part of a lot of 14 specimens collected intertidally, 800m south of Fort Ross (38°30.7’N, 123° 14.0'W), Sonoma County, California, by Dr. James H. McLean, on December 28, 1963. The neotype, partly dis- articulated, (LACM 1855), and specimen from the neo- type lot (LACM 1856), are placed in the repository of the Los Angeles County Museum of Natural History. Other specimens from the neotype-lot are deposited at the Calli- fornia Academy of Sciences (CASIZ, Type Series no. 701), Zoological Institute of the Academy of Sciences in Lenin- grad, USSR (no. 1861), Laboratoire de Malacologie, Mu- seum National d’Histoire Naturelle, Paris, and in Iwao Taki Collection, Japan. Type Locality: ‘‘California,” as originally given by Mip- DENDORFF (18472). In a subsequent report, MIDDENDORFF (1847b) added “‘Kalifornien, namentlich die friiher Russ. Kolonie Ross. Mertens hatte das Thier dort erbeutet.”’ In view of this statement, the type locality is here restricted to the presently called Fort Ross (38° 31’ N, 123° 14’ W), Sonoma County, California. Original Description: First read publicly on December 11, 1846, but published only on April 20, 1847: “Chiton testa externa ovali elevata carinata opaca, aspera, fusco- cinerea; valva antica valvae ultimae area postica, valuarum denique intermediarum areis lateralibus radiatim ex- presse granulososcabris. Valuarum intermediarum areis centralibus et valvae ultimae area antica longitudinaliter exsculpte-costatis, costis medianis postica versus dichoto- mis; costarum interstitia lamellults erectis transversis in loculamenta dissepta. Valva antica dentibus marginalibus 13 et radiis granulososcabris 26. Valva ultima margine postico convexo dentibus 13 et radiis granulososcabris 20. Valvarum intermediarum radiis granulososcabris quin- que. Pallium marginale epidermide fuscocinerea, squamis aspera, obtectum. Squamae hae in series oblique decur- rentes ordinatae. Branchiarum series ab initio secundae Explanation of Figures 7 to 6 Figure 1: Lepidozona mertensi. Neotype (in text), 33.0mm long (LACM 1855) Figure 2: Lepidozona mertensi. Neotype. Close-up of lateral areas Figure 3: Lepidozona cooperi. 28.2mm long, Bolinas, California (CASG 30915) Figure 4: Lepidozona cooperi. Close-up of specimen in Figure 3 to show detail of lateral areas Figure 5: Lepidozona pectinulata. 16.3mm long, San Diego, Cali- fornia (ANSP 118664) Figure 6: Lepidozona pectinulata. Close-up of specimen in Figure 5 to show detail of lateral areas [Ferreira] Figures 7 to 6 Tue VELIGER, Vol. 21, No. 1 Vol. 21; No. 1 tertiae partis totius animalis longitudinis ad vicinitatem ani usque porrecta. Lamellarum branchialium numerus circiter 36. Adulti longitudo 0,23 Decim. Patria: Califor- nia.’ (MIDDENDORFF, 18474: 118). Description: Neotype (Figures 1, 2) is oval in outline. Shell and girdle are a rather uniform reddish brown with some darker diffused blotches in the pleural areas; 2 wide bands of a creamy-white color cut across the specimen, transversally, at the level of valves ii and vii. The speci- men, preserved in ethyl alcohol is perfectly flat; it mea- sures 33.0mm in length (including girdle), 19.2 mm in width (at the iv level), and 5.2mm in height. Width/ length ratio: 0.58. Jugal angle about 101°. The tegmentum general surface is minutely granulose. The anterior valve displays some 29 radial rows of very well defined tubercles. The tubercles are round and mea- sure about 250 pm in diameter and height; they are clearly separated from each other by a distance at least as large as their diameter. There are about 7 - 9 tubercles per ra- dial row; the tubercles towards the top of the valve have fallen off, but their still visible scars indicate that there might have been about 10-11 such tubercles per radial tow. On the valve there are no ribs as such; the rows of tubercles define by their presence “‘ribs’”’ that are only virtual. Otherwise, the surface of the valve is smooth, al- most glossy, flat and undivided by sulci or undulations. The intermediate valves, ii to vii, show well defined lateral areas bearing 4 - 5 similar rows of tubercles disposed in a radial fashion. The central areas display some 14 - 15, well carved, longitudinal riblets to a side, riblets which tend to diverge forward moderately; between the riblets there is coarse but definite latticing, which becomes obsolete or totally absent towards the jugum. The jugal tract riblets tend to diverge forward, most particularly on valve ii where they outline a wedge-like figure. Posterior valve sculptured in conformity with the other valves. The mucro is central, well defined, but not prominent; the post mucro area Is relatively flat except for the presence of about 20 radial rows of tubercles. The girdle is about 2.5 mm wide, covered with imbri- cating scales. The scales are strongly convex, and some show a prolongation, nipple, or mammilla, on the dorsal edge [an observation already made by MIDDENDORFF (1847b, plt. fig. 2d), and LeLoup (1940, fig. 30)]. The scales attain sizes of 450 um in length. The surface of most scales appears to be smooth or minutely granulose; some occasional scales show very faint, almost obsolete stria- tions. The articulamentum is white. Sutural laminae are sharp, semioval, relatively short. Sinus is moderately shal- low; sinus laminae show a few, irregular pectinations, and are often neatly demarcated from the adjacent sutural THE VELIGER Page 21 laminae by a small notch. Eaves are solid. Insertion teeth are clean cut, sharp, and relatively short. Slit formula is TS Hite The radula measures 13.0mm in length. Radula rela- tive length (length of radula/length of specimen) is 39%. Number of rows of teeth, 33. The median plate is very wide anteriorly (400m) where it displays a thin blade recurved ventrally; medially, the plate narrows rapidly to 100um in diameter; posteriorly, it enlarges again into a bulge that resembles two half-joined spheres (Figure 34). Figure 34 Radula (median, intermediate, and uncinated plates) of the Neo- type of Lepidozona mertensii (Middendorff, 1847) (camera lucida) The intermediate plate (first lateral) has a robust recurved knobby growth at each outer-anterior corner. The un- cinated (second lateral, major lateral) plate has a unicus- pid blade, about 400m long. On the inner face of the shaft, immediately underneath the blade, there is a rather thick and long (200um x 100um) tubercle pointing in- wardly. This tubercle is obviously very fragile for its pres- ence cannot be demonstrated in but a few teeth; but the fact that it is a normal feature of the Lepidozona mertensit radula has been verified many times in other specimens of the same species obtained at the same and other collecting sites. Scanning electronic micrographs (SEM) of the girdle scales were obtained through the courtesy of Hans Bertsch, Donner Research Laboratory, University of Cal- ifornia, Berkeley (Figures 20, 27) from another specimen: The hypotype, dry and flat, measures 26.4 mm in length; it was collected by A. J. Ferreira, on August 4, 1973, at Lovers’ Point, Monterey Bay (36°37’ N, 121°55’ W), Mon- terey County, California, in 5 m of water (AJF 56). Page 22 Individual Variation: In color, Lepidozona mertensti varies appreciably although remaining within the red- orange hues. Within the basic coloration, there are often markings in the form of triangular blotches at the jugum, or dark brown suffusions along the pleural areas, or a pep- pering of lighter (or darker) specks throughout the teg- mentum. Rather characteristic of the species is the pres- ence of one or two transversal bands of a lighter color, creamy-orange to white. When present, the posterior transversal band covers most of the vii valve and adjacent girdle, while the anterior transversal band covers the ii valve and adjacent girdle. Among 83 specimens (7 lots) from Monterey Bay, California, g specimens had a single band (on vii), and 11 had a double band. Seemingly the posterior band is much more common than the anterior band for I have never seen a specimen with anterior band without a posterior one. Color does not seem to be cor- related to geographic location, depth, or any other recog- nizable aspect of the habitat. Individual variation in meristic characteristics is sum- marized in Table 1, based on a random sample of 20 adult specimens from Monterey Bay, California. As to size, specimens measuring up to 45 mm in length were found in several lots. Unusually large specimens were collected at Victoria, Vancouver Island, Canada, the largest measuring 51.9mm in length, 30.8mm in width, and 10.7 mm in height (Crittenden Colln., leg. S. Critten- den intertidally, June 1970). Specimens above 7 - 8mm in length were found to display all of the identifying charac- teristics of the species. The smallest specimens examined, 4-5mm long, already showed the typically convex girdle scales, often faintly striated, but with no mammillation; in contrast with larger ones, these small specimens usually display a spiculose fringe. Distribution: Leptdozona mertensii seems to have a con- tinuous distribution between the parallels 30° N and 58° N, between upper Baja California and Alaska. The northernmost finding in the examined collections is Auke Bay (58°21’N;134°41’ W), 24km NW of Juneau, Alaska (CASIZ, leg. J. E. Bailey, 1 adult specimen, at 25, m). The southernmost finding is Sacramento Reef, just S of Isla San Geronimo (29°43'N, 115°45’W), Baja California, THE VELIGER Vol. 21; No. 1 Mexico, 1 specimen at 6- 12m (LACM 71-91, leg. J. H. McLean, Sept. 26 - 27, 1971). Two specimens were found at Kellet Channel, south of Cedros Id. (27°57'N, 115°08' W), Baja California, Mexico (LACM 71-159, leg. J. H. McLean & P. LaFollette, R/V Searcher, Oct. 20, 1971), sizes 18 and gmm in length, and another specimen, 7 mm long, found at the southern tip of Natividad Island (27°52'N, 115°11' W), Baja California, Mexico, (LACM 72-116, leg. J. H. McLean, Sept. 25, 1972); but they were referred to L. mertensii only tentatively, their small size, and a few ambiguous features precluding a positive iden- tification. Between these two extreme points, Lepidozona mer- tensit was found often abundantly in many other collect- ing stations, including the offshore islands of San Geron- imo (LACM 71-91), San Nicolas (LACM 72-100), Catalina (LACM 65-6), Santa Cruz (LACM 63-5), San Miguel (LACM 67-38), Farallon (LACM 62-9), San Juan (CASIZ- AGS 10097; CASG 18058; LACM 66-39), Vancouver (LACM 63-31, 63-32, 73-35, 73-38, 73-39, 73-40), Queen Charlotte (LACM 69-52), Baranof (CASG 43941; LACM 73-13, 73-15, 73-16), Kosciusko (CASIZ 32430), Dall (CASG 32433, 32564), Forrester (SDNH 23436; UCLA 22317). The recorded depth range of Lepidozona mertensii ex- tends from the intertidal zone to about 100m (CASG 32536, 36334 off San Pedro; CASG 24147, Monterey Bay, California). Lepidozona mertensii has been reported in northern Japan, at Hakodate and Mutsu Bay (Is. Tak1, 1938: 390 - 393; 1962: 41). Remarks: The presence of Leptdozona mertensit at Guadalupe Island, Mexico, as reported by CHACE (1958) and A. G. SMITH (1963), must be considered as misidenti- fications for the rather similar Lepidozona guadalupensis Ferreira (herein), as concluded from the examination of the material collected at Guadalupe Island by M. Wood- bridge Williams, in July 1946 (CASIZ G-32746), by C. L. Hubbs et al. (SDNH 9957), and recently by Welton L. Lee & A. J. Ferreira (AJF 210-211). To my knowledge, Lepidozona mertensit has not been collected at Guadalupe Island. Explanation of Figures 7 to 12 Figure 7: Lepidozona scabricostata. 14.5mm long, Cordell Banks, California (CASG 43983) Figure 8: Lepidozona scabricostata. Close-up of specimen in Figure 7 to show detail of lateral areas Figure 9: Lepidozona willetti. Paratype (CASG 1123) Figure 10: Lepidozona willetti. Close-up of specimen in Figure 9 to show detail of lateral areas Figure rr: Lepidozona retiporosa. Topotype, 13.0mm long (CASG 43840) Figure 12: Lepidozona retiporosa. Close-up of specimen in Figure 11 to show detail of lateral areas [FrrreIRA] Figures 7 to 12 Tue VELIGER, Vol. 21, No. 1 Figure ro Figure 9 Figure 11 Vol. 21; No. 1 Lepidozona cooper (Dall, 1879) (Figures 3, 4, 22, 23) Ischnochiton cooperi Daut, 1879, 1: 296, fig. 15 (radula); Woop « RayMonpD, 1891, 5: 58; Pitssry, 1892, 14: 127, plt. 26, figs. 27-30 (in section Lepidozona); 1898, 50: 288; HEATH, 1904, 56: 257; 1905, 29(12): 391 - 392; BERRY, 1907, 21 (5): 51; PACKARD, 1918, 14 (2): 293 - 294; CHACE & CHACE, 1919, 2 (6): 3 (fossil); 1933, 46 (4): 124; DALL, 1921, 112: 192 (in section Lepidozona); OLDROYD, 1927, 2 (3): 281 (in section Lepidozona); JOHNSON & Snook, 1927: 564, fig. 670; SIMROTH & HOFFMANN, 1929: 314; STOHLER, 1930, 91 (5/8): 151, 155; LeLoup, 1940: 12-15, figs. 34-37; RickeTrs & CALvIN, 1962: 89, 453, pit. 19, fig. 4 Ischnoplax cooperi, THIELE, 1893, 2: 376, plt. 31, fig. 2 (radula) Ischnochiton (Lepidozona) cooperi, BERRY, 1922, 11: 473, pit. 11, figs. 1-12 (fossil); A. G. SMitn, 1947: 18; A. G. SMITH & GORDON, 1948, 26: 207; PALMER, 1958: 278 - 274, pit. 34, figs. 1 - 6 Lepidozona cooperi, BURGHARDT & BURGHARDT, 196ga, 12 (2): 228; 1969b, 21, plt. 2, fig. 27 (in color); Rice, 1971: 20, pit. 4, fig. 10 (in color); ABBorT, 1974: 395, fig. 4641; A. G. SmitH in LicuT’s, 3rd ed., 1974: 463, 465, plt. 109, fig. 5 Ischnochiton cooperi acutior Carpenter in DALL, 1919, 55 (2283): 508; DALL, 1921, 112: 192 (in section Lepidoz- ona); OLDROYD, 1927, 2 (3): 282; WILLETT, 1935, 49 (2): 44; PALMER, 1945, 58 (3): 101; 1958: 274, plt. 34, fig. 16 (synonymized with I. coopert); A. G. SmiTH, 1977, 19 (3): 222-223 (synonymized with Lepidozona coopert) Nomenclatural Comments: The name Ischnochiton cooperi was first published by Da.t (1879) who attributed it to Carpenter whose unpublished manuscript he had been “authorized to use” (DALL, l.c.: 282). Dall limited himself to describe and figure the radula; but from all appearances the description was his own, not Carpenter’s, as revealed through the examination of the pertinent pages in Carpenter’s manuscript made available to me through the courtesy of Dr. Joseph Rosewater, National Museum of Natural History, Washington, D.C. Manu- script names having no standing in taxonomy, Dall’s pub- lished account, an “‘indication”’ in the sense of Articles 16, 17 and 24.b of the International Code of Zoological No- menclature (ICZN), clearly establishes the authorship of the species as Dall’s. The synonymy of Ischnochiton cooperi acutior Carpen- ter in Dall, 1919, was suggested by Dall himself with the comment that “the only differences from J. cooperi I could perceive were that the specimens of the variety acutior were lighter in color, more emphatic in sculpture... In a group where color is often without systematic value, these differences seem hardly worthy a name...” (DALL, 1919: 508). From the examination of the holotype (USNM TiERVEEIGER Page 23 30734), A. G. SmiTH (1977: 223) concluded “that Lepi- dozona cooper: acutior merely represents a young phase of L. cooperi...’; the study of A. G. Smith’s color slide of the holotype (CASIZ, Color Slide Series No. 2048) led me to the same conclusion. The synonymy of acutior had also been suggested by PALMER (1958: 274) upon the ex- amination of specimens labelled “‘types’’ in the Carpenter Collection at the Redpath Museum, Montreal, Canada. However, a curious fact must be noted here: Although the 5 specimen-lot from Todos Santos Bay (Redpath Museum no. 18) figured in PALMER (1958: plt. 34, figs. 1-5) are unquestionably Lepidozona cooperi, the lot of 6 speci- mens from “near S. Diego’ (Redpath Museum no. 8) is not correctly identified. Despite being accompanied by a characteristic Carpenter label of white ink on glass which reads ‘“‘Ischnochiton cooperi, var. acutior,’ and having been regarded and photographed as such by PALMER (1958: plt. 34, fig. 6), all 6 specimens in the Redpath Museum no. 8, examined on a loan through the courtesy of Dr. Vincent Condé, Redpath Museum, are of Lepidoz- ona sinudentata (Carpenter in Pilsbry, 1892). Diagnosis: Chitons of medium size (up to 4cm), uni- form color of greenish, gray, or brown tones. End valves and lateral areas with rows of strong tubercles on radial ribs separated by well defined sulci. Central areas with longitudinal riblets, cross-ribbed. Articulamentum blue. Girdle scales convex, oval, with deep striations. Type Material: “No specimens have been found which could be identified as type for Dall’s description” (PAL- MER, 1958: 273). Since further search for Dall’s original material proved fruitless, a neotype specimen is here des- ignated and illustrated in accordance with Article 75 of ICZN (London, 1964). The specimen chosen as neotype is part of a lot of 8 specimens collected by myself (AJF 149) at Cayucos (35°27'N, 120°54’W), San Luis Obispo County, California, intertidally, on April 11, 1974. The neotype (partly disarticulated) and its radula are in re- pository at the California Academy of Sciences, Depart- ment of Geology (CASIZ, Type Series No. 702). Speci- mens from the neotype-lot are deposited at the Los An- geles County Museum of Natural History (LACM 1858), National Museum of Natural History (USNM 770961), and Academy of Natural Sciences of Philadelphia (ANSP 344915). The holotype of Ischnochiton cooperi acutior is at the National Museum of Natural History (USNM 30734). Type Locality: Cayucos (35°27'N, 120°54' W) San Luis Obispo County, California. The locality of Dall’s speci- men is unknown (PALMER, 1958: 273). Page 24 Description: Datu (1879: 266; fig. 15) only described and figured the radula. The earliest full description of the species comes from Pitspry (1892, 14: 127; figs. 27 - 30) whose material [ANSP 118659] has been regarded as ‘‘typ- ical’’ by some authors. The neotype is oval and somewhat carinated. The color is a uniform dingy gray. Dried, but fully extended, it mea- sures 36.8mm in length, 21.5 mm in width, and 7.0mm in height. Width to length ratio: 0.58. Jugal angle about 96°. The anterior valve displays about 20 poorly differen- tiated radial ribs which show a tendency to twin towards the periphery. The ribs are crested by well formed tuber- cles, oblong rather than round, which show a tendency to become confluent. On average the tubercles measure 0.3 mm in diameter; there are about 15 tubercles on each rib. The posterior valve shows, in the post mucro area, a sim- ilar sculpture of some 20 radial ribs crowned by a row of tubercles; the mucro is central, well defined but not conspicuous. The lateral areas of the intermediate valves bear 4 - 6 tuberculated ribs, also with a tendency to bi- furcate towards the periphery. The central areas have about 18 - 20 longitudinal riblets per side, neatly cross- ribbed for a definite lattice effect. The jugal tract has only vestigial cross-ribbing; it has a tendency to diverge for- ward, particularly on valve 1i where the riblets outline a wedge-like figure. The articulamentum is light blue in color. Sutural lam- inae are sharp, semioval, and separated by a relatively shal- low sinus. Sinus laminae are irregularly. pectinated, and separated from the adjacent sutural laminae by a small notch. Eaves are solid. Teeth are sharp-edged, clean-cut, and straight. Slit formula 10-1 - 11. The girdle is about 2.5mm wide, covered with imbri- cating oval scales. The scales are moderately convex, and display some well marked undulations, 8 - 10 per scale, which define that many ribs and striations. The largest scales average 360 um in length. THE VELIGER Vol. 21; No. 1 The radula measures 13.2mm in length, and has 34 rows of mature teeth. The relative length of the radula is 36%. The median plate is wide anteriorly (330m), then narrows rapidly in its middle part (100 um) to bulge again posteriorly in a sort of spheroid; from its anterior edge, a thin blade curves ventrally. The intermediate plate has a strong, knobby growth in the outer-anterior corner. The uncinated plate has a long (450 ym) unicuspid blade on a shaft about 700 pm long. A thick and long tu- bercle in the upper part of the uncinated plate points inwardly. The specimen in the photograph (Figure 3, 4), measures dried, but fully extended, 28.2 mm in length, 17.3 mm in width, and 6.8mm in height. It is part of a lot of 5 speci- mens collected at Bolinas, Marin County, California (CASG 30915). The specimen used for the SEM micrographs of the girdle scales (Figures 22, 23), measures 30 mm in length, and was collected at Point St. George, Del Norte County, California (CASG 53072). Individual Variation: Lepidozona cooperi varies little in color, staying within the range of dark browns, greens, or grays, for an overall dingy, inconspicuous appearance. Variation in meristic characteristics are summarized in Table 1. In size, only a few specimens examined were longer than 4omm. The largest specimen seen measures 44.5mm (SDNH 53812, Crescent City, California). Speci- mens as small as 5 mm already show identifying charac- teristics, particularly the distinctive girdle scales. Distribution: The known range of Lepidozona cooperi extends from latitude 32° N to 48° N. The northernmost record is Neah Bay (48°22' N; 124°37' W), at the entrance of the Strait of Juan de Fuca, Washington (RICE, 1971). The southernmost locality is Puerto Santo Tomas (31°34’ N; 116°40' W), Baja California, Mexico (LACM 67-2, leg. J. H. McLean, Jan. 8-10, 1967). The species has been recorded, too, from Catalina (DALL, 1921), and Sta. Cruz Islands (AJF, Dec. 1970) on the outer coast of California. Explanation of Figures 13 to 19 Figure 13: Lepidozona guadalupensis Ferreira, spec. nov. Paratype 13.0mm long (LACM 1857) Figure 14: Lepidozona guadalupensis Ferreira, spec. nov. Close-up of specimen in Figure 13 to show detail of lateral areas Figure 15: Lepidozona sinudentata. Topotype, 15.0mm long, Mon- terey Bay, California (AJF 89) Figure 16: Lepidozona sinudentata. Close-up of specimen in Figure 15 to show detail of lateral areas Figure 17: Lepidozona sinudentata. 17.5mm long specimen from Todos Santos Bay, Baja California, Mexico, ex G. Willett collection (UCLA 22382). Close-up of lateral areas Figure 18: Lepidozona sinudentata. 11mm long specimen from San Diego, California (CASG 40837). Close-up of lateral areas Figure 19: Lepidozona sinudentata. 12mm long specimen from Carmel Bay, California (CASG 53074) : scales on the under- side of the girdle approximately X 300 SEM micrographs by Hans Bertsch [FerREIRA] Figures 13 to 19 Tue VELIGER, Vol. 21, No. 1 ie ~ aye ee F ool x oe . Figure 14 6 igure I F 23> ee ee Figure 18 Vol. 21; No. 1 The known depth range is from intertidal to about 20 meters. Remarks: In size, shape, and valve sculpture, Lepido- zona cooperi is rather close to L. mertensii. The main dis- tinguishing features are in the tuberculated radial ribs, the color of the articulamentum, and the very decidedly different girdle scales. To a considerable extent, the two species share range and habitat, although L. cooperi seems to favor shallower depths than L. mertensii. In general appearance, size, and coloration, L. cooperi is remarkably similar to Lepidozona coreanica (Reeve, 1847) from Japan; the two species may be regarded as cognates, the differences in sculpture being rather subtle and difficult to pinpoint except for the distinctive, though similar, girdle scales. Lepidozona pectinulata (Carpenter in Pilsbry, 1893) (Figures 5, 6, 28) Ischnochiton (Lepidopleurus) pectinatus CARPENTER, 1864a: 612 (Reprinted, 1872: 98), nomen nudum [not Chiton pectinatus Sowerby, 1840]; 1866, ser, 1, 3: 211-212 Lepidopleurus pectinatus CARPENTER, 1864b: 649 (Reprinted, 1872: 135) [=Ischnochiton cooperi Carpenter in Dall, 1879, in part, fide Pitssry, 1893, 14: 129] — Cooper, 1867: 22; 1870: 59 Ischnoplax pectinatus, KEEP, 1887: 112 (Reprinted, 1888, 1891, & 1893) “Chiton (Lepidopleurus ?) pectinulatus Cpr.”, DALL in OR- ' cuTT, 1885: 544, nomen nudum Lepidopleurus pectinulatus Carpenter in MS, Pitssry, 1893, 14: 129 [syn. of Ischnochiton clathratus (Reeve, 1847) in ian pectinulatus, Berry, 1922: 412, 414, 421, tbl. 1 (fossil) Ischnochiton (Lepidozona) pectinulatus, BERRY, 1922: 471 - 472, plt. 10, figs. 4-6 “Ischnochiton punctulatissimus Carpenter”, Lowe, 1904: 19 [? error for I. pectinulatus] Ischnochiton clathratus (Reeve, 1847), P1LsBRY, 1892 - 1893, 14: 128 - 129 (in part); Keep, 1904: 349; Berry, 1907: 51; Cuace, 1917: 30 (fossil) [= J. (Lepidozona) sanctaemoni- cae Berry, 1922, fide Berry, 1922: 471, footnote]; OLp- ROYD, 1924: 193; 1927: 282; LELoup, 1940: 3, 15 - 18; figs. 38-41 Ischnochiton (Ischnochiton) clathratus (Reeve, 1847), DALL, 1921: 192 (in section Lepidozona) Lepidozona pectinulata, FERREIRA, 1974: 165; A. G. SmitH, 1977: 216, 229 - 231 Ischnochiton bryanti Dati, 1919: 503; 1921: 190; A. G. SMITH, 1947: 18; BURGHARDT & BURGHARDT, 1969: 16 (syn. of I. brunneus Dall, 1919); ABBotr, 1974: 395 Ischnochiton brunneus DALL, 1919: 504; 1921: 190; OLDRoyD, 1927: 271; A. G. SmitH, 1947: 18; BURGHARDT & Burc- HARDT, 1969: 16 (with syn. J. bryanti Dall, 1919); ABBOTT, 1974: 395 THE VELIGER Page 25 Ischnochtton (Lepidozona) californiensis BERRY, 1931: 255, - 258, plts. 29, figs. 1-2; A. G. Smitu, 1947: 18; A. G. SMITH & GorDON, 1948, (4) 26 (8): 207; PALMER, 1958: 272-273; plt. 31, figs. 5,6 Ischnochiton californiensis, THORPE, 1962: 205 Lepidozona californiensis, A. G. SmitH, 1960: 56; fig. 38, 8 (fossil); McLEAN, 1969: 64; fig. 35,5; BURGHARDT & Burc- HARDT, 1969: 20, 43, plt. 2, fig. 26 (in color); PHILLIPs, 1971: 22; ABBOTT, 1974: 395 Nomenclatural Comments: CARPENTER (1864b: 612) in- troduced Ischnochiton (Lepidopleurus) pectinatus with- out a description. The nomen nudum situation was soon remedied when Carpenter provided a short description of the species (1864b: 649), and a full description later (1866, 3: 211 - 212). According to Pitssry (1893, 14: 129), Car- penter’s first description of Lepidopleurus pectinatus [so inadequate that it is impossible to say to what taxon it would apply] referred to “I. cooperi, Cpr.’’; and the sec- ond, much fuller description of the species (1866) “seems to have included both this species [Ischnochiton clathratus (Reeve, 1847), sensu PiLsBry, 1893] and I. cooperi.” How- ever, afterwards, ‘‘upon receipt of better material,’ Car- penter distinguished J. cooper: from I. pectinatus, and [in the realization that the name “‘pectinatus’’ was preoccu- pied by Chiton pectinatus Sowerby, 1840] re-named the latter pectinulatus. Nomenclatural difficulties might have been minimal at this point were it not for Pilsbry’s misunderstanding of Chiton clathratus Reeve, 1847, as the “species that seems to replace I. mertensii south of Monterey . . . a dingy, lus- terless shell resembling mertensii in the shape of the girdle scales...’ (PILSBRY, 1893: 129), and, as such, senior syn- onym of J. pectinulatus Carpenter in MS. The misunderstanding so created was not unraveled until BEERY (1931) pointed out that Pilsbry’s interpreta- tion of Chiton clathratus Reeve, included two distinct spe- cies, Lep’dozona clathrata (Reeve, 1847) confined to the Gulf of California, Mexico, and “the commonest southern California Lepidozona’ to which old collectors [like Henry Hemphill (A. G. Smitu, 1977: 230)], and authors [like Berry himself (1922)] had referred to as “‘pectinu- latus.”’ However, BERRY (1931) reached the conclusion that Carpenter's ‘‘pectinulatus”’ was not a valid name for the southern California species since it had been first pub- lished (PitsBry, 1893) in synonymy, a fact which, by the old Régles (1905) [in a rule not changed until the ICZN of 1963], made it unavailable for purposes of nomencla- ture. In this frame of opinion, Berry concluded that the southern California species had been left without a valid name, and proceeded to rename it Ischnochiton (Lepido- zona) californiensis Berry, 1931. Page 26 It now seems that Berry’s new name for the species was unnecessary for the following reason: 1) Carpenter's sec- ond description (1866) of Ischnochiton (Lepidopleurus) pectinatus is quite adequate and explicit even by present standards, 2) the existence of a syntype series (Redpath Museum no. 70) of J. pectinatus labeled by Carpenter as “type” (photographed in Pater, 1958: plt. 31, figs. 5, 6) [not mentioned in either Pirssry, 1893, or BERRY, 1931], and 3) the fact that the name “pectinulatus” was clearly validated by Pitssry (1893: 129) as replacement for “pec- tinatus.”” Meanwhile, Berry’s objections to the use of the name “‘pectinulatus’”’ were further weakened in 1963 when the ICZN modified the rule 11(d) to allow the use of such names in synonymy if, before 1961, they had been treated as available names. It is ironical to observe that BERRY (1922) himself clearly used L. pectinulata as an available name,thus unwittingly providing the basis for invalidat- ing his new name “‘californiensis.”’ In this respect, some unpublished notes left by Pilsbry [conveyed to Allyn G. Smith (personal communication) through R. Tucker Abbott, then with the Academy of Natural Sciences of Philadelphia] and clearly intended for publication, are of historical interest. With the kind per- mission of Dr. Robert Robertson (in litt., 22 October, 1973), I quote from Pilsbry’s notes on the subject of ““Lepidopleurus’ pectinulatus Cpr. MS”: “.. . Carpenter had formerly called the southern California shell ‘L. pec- tinatus’ (not of Sowerby) though this is known by speci- mens he labeled rather than by his inadequate definition. I stated (p. 129) [Manual of Conchology, 1893, vol. 14] that he had ‘renamed the present form pectinulatus’. The ‘present form’ referred to being that I had just described [C. clathratus Reeve]. My description and figures were from Californian specimens... My definition did not ‘in- clude both Panamic and Californian races’ as stated by Dr. Berry . . . I, as it now appears erroneously, considered Reeve’s unlocalized C. clathratus to be the Californian species .. . The Californian species was already commonly known under the name pectinulatus when I wrote the monograph ... There seems to be no necessity for giving a new name in view of the treatment of the form in the Manual of Conchology. It should stand as Ischnochiton (Lepidozona) pectinulata (‘Cpr.”) Pils.... with the sy- nonymy as given by Berry (1931: 255) to which is to be THE VELIGER Vol. 21; No. 1 added I. (L.) californiensis Berry, l.c....a name which appears to me to be superfluous.” Pilsbry’s belated con- clusions are supported by the finding of two lots of speci- mens in the Type Collection of the Academy of Natural Sciences of Philadelphia associated with the name pectin- ulatus. One (ANSP 118664) consists of 13 specimens ac- companied by three labels which, combined, read: “Lepi- dopleurus pectinulatus Cpr.; San Diego, California; col- lected by Henry Hemphill; on rocks between tides; Type, figs. 31 - 33” [the statement ‘““Type, figs. 31 - 33’ obviously refers to Pilsbry’s monograph in Tryon’s Manual of Con- chology, 1892 - 1893, vol. 14; and together with the iden- tification J. pectinulatus Cpr., it is lettered in ink, likely by Pilsbry himself (SmitH, 1977: 230)]. The second lot (ANSP 118662), consists of two specimens; the label reads “L. pectinatus Cpr./I. clathratus Rv....” the name “clathratus” had been crossed out, and the name “‘califor- niensis’” written in pencil over the name “‘pectinatus’’; to the right of the card on which the larger specimen seems to have been mounted, a pen-written “2nd measurement/ M.C. p. 128” suggests that the specimen was used for one of the measurements published in the Manual of Con- chology (SMITH, 1977: 229). The specimens in both lots, available through the generosity of Dr. Robert Robertson, Academy of Natural Sciences of Philadelphia, are unques- tionably conspecific with Ischnochiton (Lepidozona) cali- forniensis Berry, 1931, and with Carpenter’s syntype series of I. pectinatus at the Redpath Museum. It is interesting to note that prior to Pilsbry’s mono- graph, the name “‘pectinulatus Cpr.’ had already been introduced in the literature, albeit as a nomen nudum, by Dati (in Orcutt, 1885) who had been working from Carpenter’s MS, presumably the same MS used by Pilsbry. From the marshalling of all the evidence, it seems ap- propriate to call the species in question Lepidozona pec- tinulata (Carpenter in Pilsbry, 1893), and so bring the whole taxonomic problem to rest. The synonymization of Ischnochiton brunneus Dall, 1919, and Ischnochiton bryanti Dall, 1919, is based upon Dall’s original descriptions, and the examination of the respective holotypes made available through the kindness of Dr. Joseph Rosewater, United States Museum of Na- tural History, Washington, D.C. Explanation of Figures 20 to 27 Figure 20: Lepidozona mertensit. Girdle scales. approxim. X 240 Figure 21: Lepidozona mertensi. Girdle scales. approxim. X 100 Figure 22: Lepidozona cooperi. Girdle scales. | approxim. X 300 Figure 23: Lepidozona cooperi. Girdle scales. | approxim. X 100 Figure 24: Lepidozona scabricostata. Girdle scales. approx. X 300 Figure 25: Lepidozona scabricostata. Girdle scales. approx. X 60 Figure 26: Lepidozona retiporosa. Girdle scales. approxim. X 650 Figure 27: Lepidozona retiporosa. Girdle scales. approxim. X 400 SEM micrographs by Hans Bertsch Tue VELIGER, Vol. 21, No. 1 [FERREIRA] Figures 20 to 27 re: F igure 23 J u) Figure 27 Nees Ne ry es Si ; ae oe = i) 3 Vol. 21; No. 1 THE VELIGER Page 27 Type Material: ‘There are in the Redpath Museum two complete specimens and three separate plates which were labelled by Carpenter, ‘Type La Paz Pease’’’ (PAL- MER, 1958: 273). Although the locality of the specimens must be in error, the specimens must be regarded as a syntype series. The one specimen figured in PALMER (1958: plt. 31, figs. 5, 6), whose dimensions are given as 25 x 10mm, is here designated as lectotype; the other two in the lot as paralectotypes (Redpath Museum No. 70). Ischnochiton (Lepidozona) californiensis Berry, 1931: Holotype in Berry Colln. (Cat. No. 5226). Paratypes in Berry Colln. (Cat. No. 3119), SDNH, ANSP, USNM, British Museum (Natural History), and Stanford Univer- sity (Department of Geology). Color slides of paratype (ANSP 161525) at CASIZ, Color Slide Series Nos. 2968 - 2969 (A. G. Smith). Ischnochiton brunneus Dall, 1919: Holotype (USNM 58734a). Color slides at CASIZ, Nos. 2972 - 2973 (A. G. Smith), and Nos. 3107 - 3108 (AJF). Ischnochiton bryanti Dall, 1919: Holotype (USNM 253826). Color slides at CASIZ, Nos. 2965 (A. G. Smith), and No. 3109 (AJF). Diagnosis: Chitons of medium size (up to about 4cm), uniformly colored mostly in tones of muddy brown to orange. End valves and lateral areas of intermediate valves with strongly granular radial ribs. Central areas with lon- gitudinal riblets, clearly cross-ribbed. Girdle scales imbri- cated, strongly convex, faintly striated, and mammillated. Type Locality: As mentioned above, the locality attrib- uted to the syntypes must be in error. The first specimen reported as J. pectinatus Carpenter (1864a: 612), a nomen nudum, was from Catalina Island, California. The second reference (1864a: 649) mentioned specimens from Santa Barbara Islands. Carpenter’s 1866 description lists Cata- lina and Santa Barbara Islands. The type locality is here restricted to Catalina Island, California. Original Descriptions: “Olive, strong sculpture over shagreened surface: side areas ribbed; outer margin and inner sutures pectinated. Bch.” (Carpenter, 1864a: 649). “State Collection, No. 1073. L.t.L. Mertensiv’ simili, sed omino olivaceo; areis diagonalibus radius plerumque iv. dense tuberculiferis, radioque altero suturali tuber- culis inflexis, margines valuarum pectinantibus; costis transversis crebris validis; costulis longitudinalibus acutis distantibus superantibus, quarum margines suturas anti- cas pectinant; valv. term. ut in areis diag. sculptis, seriebus tuberculorum creberrimis; tota superficie minutissime tuberculata: intus, valvis centralibus untfissatis, terminal- ibus xi-xv-fissatis: scalis pallit irregularibus, confertis, minutissime longitudinaliter striatis. Long. 0.85, lat. 0.50, div. 110°. Variat: interdum aurantio nebulosa. Hab. Catalina Island, Santa Barbara Island, beach, Cooper.” (Carpenter, 1866: 211 - 212). Description: The splendid account of Lepidozona cali- forniensis given by BERRY (1931) is amply sufficient for the understanding of Lepidozona pectinulata. The fol- lowing observations are to be taken only as a supplement to, not an improvement upon that account. The specimen studied (ANSP 118664, leg. H. Hemp- hill, San Diego, Calif.), is of a uniform dark muddy brown color (Figures 5, 6). Dried, but perfectly flat, it measures (including girdle) 27.0mm in length, 16.3 mm in width, and 5.5mm in height, Width/length ratio: 0.60. Jugal angle about 99°. Anterior valve shows about 24 radial ribs, some twinning towards the periphery. The ribs are composed of a series of granules (about 15 per rib), round, close-packed; each granule is separated from the ones above and below on the rib by a space about half as wide as the granules themselves. The space between the ribs is well defined, distinct, and about as wide as the granules. Posterior valve has some 20 similar granular radial ribs; mucro is low, and inconspicuous. Post-mucro area slightly concave. In the intermediate valves, the lateral areas have about 5 similar granular ribs; the granules in the poste- rior rib tend to be elongated in the anterio-posterior direction, protruding posteriorly and so conferring on the posterior edge of the lateral area a serrated appear- ance. Central areas with longitudinal riblets (about 15 per side), with equally well developed cross-riblets which results in a marked clathrate appearance of square pits. The jugal riblets diverge forward on valve ii forming a wedge-like figure; similar, but less accentuated divergence of the jugal riblets is also seen on valve iii. The space be- tween the longitudinal riblets at the jugum is smooth, not cross-ribbed. The girdle scales are large (up to 400 um), strongly convex, faintly striated. A nipple-like pro- longation is observed at the dorsal edge of many of the scales, particularly on the larger ones closer to the valves; the nipple tends to be elongated along the edge, looking more like a crest than a nipple. The soft parts of the animal had been removed. The articulamentum is bluish white. Sutural laminae are semi- oval, moderate in size. Sinus is relatively shallow; the sinusal laminae show a few irregular pectinations and, in some, there was a small notch separating them from the adjacent sutural laminae. Teeth, eaves, and slit formula not determined. Color slides of the specimen at CASIZ Color Slide Series Nos. 3118 - 3119 (AJF). Another specimen (CASG 43928, San Diego, shore, Cal- ifornia, coll. T. S. Oldroyd, ex M. Gordon Colln.), was Page 28 used for SEM microphotographs of the girdle scales (Fig- ure 28); the specimen measures 28 mm in length; it was the largest in a lot of 27. A specimen from near the type locality (AJF 148, Bird Rock, La Jolla, San Diego County, California, leg. A. J. Ferreira, intertidally, April 10, 1974), measuring 25.0mm in length (including girdle) was used for further examina- tion: The eaves were solid, the slit formula was 11 - 1 - 12. The radula of this specimen measures 11.2mm in length, and it has 42 rows of teeth. Radula relative length, 48%. The median plate is wide anteriorly (280 um) where it sports a small ventrally recurved blade; the plate nar- rows medially (to 100 ym) and ends posteriorly in a bulg- ing spheroid, about 140 um in diameter. The intermediate plate bears a knobby growth at the outer anterior corner. The uncinated plate is unicuspid, the blade being about 280m in length, on a shaft about 550m long. On the upper part of the shaft a thick, blunt tubercle protrudes inwardly, although only visible on a few plates. Individual Variation: Color variations of Lepidozona pectinulata stay within rather narrow limits, from a uni- form dark muddy brown to orange. Some occasional speci- men shows a wide and ill-defined band of a lighter colora- tion of orange running longitudinally across the pleural and lateral areas. In size, L. pectinulata does not usually exceed 35mm in length; the largest specimen examined measures 40 mm in length (CASG, San Diego, California, ex H. Hemphill Colln.). Variation in the number of radial ribs, slit formula, etc. is summarized in Table 1, based upon a random sample of 20 adult specimens. Distribution: Lepidozona pectinulata seems to be con- fined to the San Diego Province, within the parallels 24° N and 35°N. The distribution seems to be continuous, and includes the offshore islands, with findings at Catalina Island (SDNH 57716; CASG 4055; LACM 64-26 & 71-99), San Clemente Island (SDNH 53814; LACM 66-51), San Geronimo Island (LACM 67-62), Sacramento Reef (AJF 94; LACM 71-91), San Martin Island (LACM 68-31), Na- tividad Island (LACM 72-116) and Cedros Island (SDNH 60709; LACM 67-65 & 71-92). Its northernmost record is Cayucos (35°27’N, 120°54' W) San Luis Obispo County, California (CASG 13784, H. Hemphill Colln.); the south- ernmost record is NW side of Santa Margarita Island (24°31'N, 111°57'W), Magdalena Bay, Baja California, Mexico (LACM 67-73, intertidal, leg. J. H. McLean, Dwyer Expedition, December 15, 1967). Bathymetrically, L. pectinulata has been collected from intertidal to about 20m (LACM 72-115, 50 - 65 feet, S side Piedra Colorada, SW tip Cedros Island, Baja California, Mexico, leg. J. H. McLean, September 24, 1972). THE VELIGER Vol. 21; No. 1 Remarks: The relative allopatry between Lepidozona pectinulata and L. mertensiit has been noticed since the days of Pitspry (1893: 129). In relation to the species of Lepidozona in the Gulf of California it is worth pointing out that L. pectinulata has decided affinity not only to L. clathratus (Reeve, 1847) with which it was long confused, but to L. formosa Ferreira, 1974 as well. Lepidozona sinudentata (Carpenter in Pilsbry, 1892) (Figures 75, 16, 17, 18, 19, 29) Ischnochiton (Ischnochiton) sinudentatus Carpenter MS in Pirssry, 1892, 14: 128 (in section Lepidozona); DALt, 1921: 192 (in section Lepidozona); OLpRoyp, 1927: 283 (in section Lepidozona); A. G. SmiTH, 1977: 216, 235 - 236 Ischnochiton (decipiens var. ?) sinudentatus, Pitssry, 1898: 288 Ischnochiton sinudentatus, KEEP, 1904: 349; Burcu, 1942: 7; PatMe_R, 1945; 101; LicHt’s Manual, end ed., 1954: 217, 219 Ischnochiton (Lepidozona) sinudentatus, BERRY, 1922: 476 - 477, tbl. 1, plt. 12, figs. 10-17; PALMER, 1958: 276, plt. 30, figs. 8, 9; plt. 33, figs. 1-5; A. G. Smitu, 1947: 18: A. G, SMITH & Gorpon, 1948: 208 Ischnochiton clathratus Reeve, 1847, var. sinudentatus Pils- bry, 1893 [= 1892], LeLoup, 1940: 3, 17-18 Lepidozona sinudentata, BURGHARDT & BURGHARDT, 1969: 22 - 23, 43 - 44; plt. 2, figs. 29 - 32 (in color) (with syn. L. gallina Berry, 1925); Apsott, 1974: 395 (with syn. L. berry: (Dall, 1919)); A. G. SmMitH in Licnt’s Manual, grd ed., 1975: 463, 465, Ischnochiton (decipiens var. ?) sinudentatus, PiLsBry, 1898: 288 Ischnochiton listrum Datu, 1919: 504; OupRoyp, 1927: 271 - 272; BURGHARDT & BURGHARDT, 1969: 17; ABBorTT, 1974: 395; A. G. SmitH, 1977: 216, 227 (syn. of L. sinudentata) Ischnochiton (Ischnochiton) listrum, DALL, 1921: 190 Ischnochiton (Lepidozona) listrum, A. G. SmrtH, 1947: 18 Ischnochiton berry: Bartsch MS in Berry, 1907: 51, nomen nudum Ischnochiton berry: DAL, 1919: 507; 1921: 192; OLDROYD, 1927: 279; Burcu, 1942: 7; Licut’s Manual, end ed., 1954: 218; Apsotr, 1974: 395 (? syn. of Lepidozona sinu- dentata (Carpenter in Pilsbry, 1892)); A. G. Smrru, 1977: 216, 220 (syn. of L. sinudentata) Ischnochiton (Leptdozona) berryt, A. G. Smitu, 1947: 18; A. G. SmitH & Gorpon, 1948: 207 Lepidozona berryi, BURGHARDT & BURGHARDT, 1969: 20, 44; plt. 2, fig. 32 (in color) Ischnochiton (Lepidozona) gallina Berry, 1925: 228 - 229; pit. 11, figs. 1, 2; A. G. Smitn, 1947: 18; A. G. SmiTH & Gorpon, 1948: 207, 208 [in error as I. (L.) golischi Berry, 1919]; A. G. SmitH, 1977; 216, 225-226 (syn. of L. sinudentata) Vol. 21; No. 1 Ischnochiton gallina, WiLLETT, 1935: 43 - 44 (syn. of I. de- cipiens Carpenter, 1892); ABBoTT, 1974: 395; fig. 4643 (syn. of L. decipiens (Carpenter in Pilsbry, 1892)) Nomenclatural Comments: By virtue of its high degree of intra-species variation, and its relatively wide bathy- metric range, Lepidozona sinudentata has given rise to much confusion, and caused the description of several nominal species which have been found wanting in ob- jective distinctions. The synonymization of Lepidozona gallina (Berry, 1925) imposed itself from the original de- scription and accompanying photographs; it had been suggested already by WILLETT (1935) who considered L. gallina and L. decipiens conspecific, and by BURGHARDT & BuRGHARDT (1969). Lepidozona berry (Dall, 1919), and L. listrum (Dall, 1919) were conclusively resolved as synonyms of L. sinu- dentata from direct examination of their respective holo- types kindly loaned by Dr. Joseph Rosewater, United States Museum of Natural History, Washington, D.C. The case of Ischnochiton decipiens Carpenter in Pils- bry, 1892, was more complex. On subjective grounds, the species has been equated with Lepidozona sinudentata. The examination of a series of 6 small chitons in the col- lection of the Philadelphia Academy of Sciences (ANSP 42122) with the label “J. decipiens sinudentatus Cpr./ Pacific Grove, nr. Monterey, Cal./H. Heath, Aug. 1,” did not reveal any differences from other specimens of the very common (in the area) L. sinudentata; Pilsbry, in fact, had already referred Heath’s specimens to L. sinudentata by citing them as “‘Jschnochiton (decipiens var.?) sinuden- tatus Cpr.” (PitsBry, 1898: 288). WILLETT (1935: 43 - 44) regarded Ischnochiton decipiens as a senior synonym of I. (Lepidozona) gallina Berry, 1925; and so did ABBoTT (1974: 395). BURGHARDT & BURGHARDT (1969: 21) cited Lepidozona decipiens with the added comment that “‘this species will probably turn out to be a synonym of Lepi- dozona sinudentata...’’ Recently, A. G. SMITH (1977: 223 - 224) concluded for the conspecificity of Ischnochiton decipiens and I. berry: Dall, 1919. Yet, on objective grounds, there is no way of knowing what the name Isch- nochiton decipiens stood for. No type material was ever found (PALMER, 1958: 274), the species was never illus- trated, and Carpenter’s description as given by PILsBry (1892: 123) is rather laconic and uninformative. Under the circumstances, it appears that J. decipiens should be considered a nomen dubium in as much as it can not be applied with certainty to any known taxon (ICZN, p. 151). Type Material: The syntype series (Redpath Museum no. 27), available through the kindness of Dr. Vincent Condé, Redpath Museum, Montreal, Canada, carried the label [in white ink: ? Carpenter’s own handwriting], THE VELIGER Page 29 “Ischnochiton sinudentatus Cpr. (Type), California.” The series consists of 4 specimens. The largest of these specimens, measuring 12.0mm in length, is here desig- nated as lectotype; it is partly disarticulated, with loose valves i, vii, and vill, permitting verification of the slit for- mula indicated by Pitspry (1892: 128) as 10-1-9. The other 3 specimens in the series are here designated as para- lectotypes; they measure 10.0 mm, 6.7 mm, and 4.9mm in length. The types are figured in PALMER (1958), the here designated lectotype in plt. 33, figs. 1 - 5, and the largest of the paralectotypes in plt. 30, figs. 8, 9. Color slides of the syntype series, as well as of the designated lectotype are deposited at CASIZ, Color Slide Series No.s 2075-77 (A. G. Smith), and 3078-80 (AJF). Ischnochiton berryi Dall, 1919: Holotype (USNM 193375), labelled “Ischnochiton berryi, Bartsch / (Fig’d type) / Pacific Grove.” Color slides at CASIZ, Nos. 2960- 61 (A. G. Smith) and 3094-95 (AJF). Ischnochiton listrum Dall, 1919: Holotype (USNM 58,734). The label reads, ‘““Type/ San Diego, Cal./ H. Hemphill.” Color slides at CASIZ, Nos. 2562 (A. G. Smith), and 3117-18 (AJF). Ischnochiton (Lepidozona) gallina Berry, 1925: Holo- type, ‘“A shell preserved dry S.S.B.757 entered as Cat. No. 4898 of the author’s collection (ex-No. 1179, collection of R. H. Tremper).” Figured in Berry (1925). Type Locality: ‘California’ as designated by Carpenter on the label attached to the type material. Following the suggestion implied in Pitspry (1892: 128), the locality is here restricted to Monterey Bay (36°45’N, 121°55’ W), Monterey County, California. Diagnosis: chitons of small size (up to 2gcm), high- arched. Color very variable with rose, brown, and white predominating, often variegated. End valves and lateral areas of intermediate valves with radial ribs, variably gra- nose. Central areas longitudinally ribbed, and latticed. Girdle scales, oval, only modestly convex, with shallow striae. Description: Lectotype—Partly disarticulated. Length of the whole specimen (estimated) 12 mm [PALMER (1958: plt. 33, figs. 1-5) gives the length of the specimen as 14 mm]. The color of the tegmentum is a uniform light brown. Anterior valve and post-mucro area of posterior valve have distinctly granose radial ribs, well separated from each other. There are about 25 such radial ribs in valve i, and 18 in valve viii [the number of ribs is obscured by glue adhering to the valves]. In the intermediate valves, the lateral areas are distinct and bear 4 - 5 similar granose radial ribs. The ribs’ granules are modest in size, almost obsolete at some points; they are larger, however, in the Page 30 THE VELIGER Vol. 21; No. 1 posterior ribs, protruding discretely into the sutural spaces. Central areas have about 16 - 18 longitudinal rib- lets per sides, riblets that become crowded and obsolete towards the jugum to which they remain parallel. Valve ii shows a wedge figure composed of forwardly diverging jugal riblets. Cross-ribbing produces a latticing effect well marked on the pleural areas but less so at the jugum. Mucro is median, not prominent. The articulamentum is white. Sutural laminae are semi- oval to quadrangular, relatively short. Sinus is relatively shallow; the sinus laminae show occasional irregular pec- tinations, and are separated from the adjacent sutural laminae by a minute notch. Teeth well cut, slightly bev- eled. Eaves solid. Slit formula 10-1-9. Girdle scales imbri- cated, oval, with about 10 shallow striae; maximum length about 200 pm. Another specimen (CASG 53074, coll. off Carmel, Cali- fornia, 9 July, 1935, at 6 fathoms, ex Hopkins Marine Station Collection), 12.0mm in length, was used for SEM micrographs of the girdle scales (Figures 19, 29), and ex- amination of the radula. The radula measures about 7.0mm in length, and has some 37 rows of teeth. Its relative length is 58%. The median plate is very wide anteriorly (140 pm) where a thin blade recurves ventrally; the plate narrows medially (to 60pm), but bulges again posteriorly into a spheroid. The intermediate plate has a small knobby outgrowth in the outer-anterior corner. The uncinated plate is unicuspid; the blade measures about 200 pm in length, the shaft about 350um in length. A thick, blunt tubercle is seen on the upper part of the shaft, pointing inwardly. The illustrated specimen, a topotype, (Figure 15, 16) of Lepidozona sinudentata, measures 15mm in length, and was collected at the Breakwater, Monterey Bay, Cali- fornia, in 13 m of water, leg. A. J. Ferreira, September 1, 1973 (AJF 89). Individual Variation: The considerable intraspecific variation in color and in sculpture displayed by Lepidoz- ona sinudentata has left many collectors uncertain as to an understanding of the species, and bewildered by an array of names. In color, L. stnudentata varies from total white to dark brown, often variegated with reds, greens, oranges, sometimes even blue. Specimens of a varied color pattern may be found, and often are, side by side under the same rock. A curious, and not uncommon color pat- tern, is that found on the type of J. “gallina” Berry, 1925, in which dark (red, maroon, or blue) transversal stripes alternate regularly with creamy-white colored ones for a zebra-like effect. It is interesting to note that there is some correlation between color pattern and depth, inasmuch as deep water specimens do not seem to vary as much in color patterns as shallow water ones do; with remarkable con- stancy, deep water specimens are a uniform medium brown, with no other color or pattern. Variations in the sculpture of the radial ribs, particu- larly noticeable in the lateral areas have likely caused much uncertainty among collectors. As some of the illus- trations here indicate (Figures 16, 17, 18), the radial ribs may vary considerably in their sculpture, boldness, num- ber, and outline, from robustly built to absent, from coarse large granulations on the radial ribs to only minute nod- ules, from being well separated to being close together. In some specimens, only the granulations in the posterior rib are well marked, sometimes elongated, commaz-like, protruding conspicuously into the sutural spaces; in some other specimens, the posterior rib may be non-granular, straight, or even absent. The correlation between these different forms and geography and depth is not clear cut: Northern specimens (Monterey) tend to have thicker and coarser radial ribs than southern specimens (San Diego); shallow specimens tend to have also bolder ribs in the lat- eral areas than deep water ones; a particular form of rib, with rather minute granules has only been found in deep water—and looked so different that for over two years, and until I examined more material from other deep water stations, I labored under the conviction of their being representatives of a new species. Variations in the central areas are not as frequent or obvious as those of the radial ribs in the lateral areas. Still, deep water specimens tend to have much more subdued longitudinal riblets, a greater number of them, more crowded together, resulting in a rather different appearance, particularly when combined with equally less marked cross-ribbing. Variation in other meristic characteristics is summarized in Table 1, based upon a random sample of 20 specimens from shallow water (down to 30m), Monterey Bay, California. Remarkably, the girdle scales were constant in their fea- tures in all specimens examined, despite differences in size, geography, or depth. Explanation of Figures 28 to 33 Figure 28: Lepidozona pectinulata. Girdle scales. approx. X 100 Figure 29: Lepidozona sinudentata. Girdle scales. approx. X 200 Figure 30: Lepidozona willett:. Girdle scales. | approxim. X 1000 Figure 91: Lepidozona willetti. Girdle scales. | approxim. X 600 Figure 32: Lepidozona guadalupensis Ferreira, spec. nov. Girdle scales approximately X 300 Figure 33: Lepidozona guadalupensis Ferreira, spec. nov. Girdle scales approximately X 100 SEM micrographs by Hans Bertsch Tue VELIGER, Vol. 21, No. 1 [FerREIRA] Figures 28 to 39 Figure 31 Vol. 21; No. 1 In size, Lepidozona sinudentata only rarely attains 2 cm in length. The largest specimen examined measures 24.5 cm (including girdle) in length; its slit formula was 12-1-12 (CASIZ, Camalu, Baja California, Mexico, leg. L. D. Miles, Apr. 24, 1951, ex Miles Colln.). Distribution: Lepidozona sinudentata seems to have a continuous distribution between latitudes 28° N and 38° N. The northernmost record is Salt Point Ranch (38°30! N, 123°19' W), Sonoma County, California (LACM 64-6, at 13m, leg. J. H. McLean, February 21, 1964). The south- ernmost record is Thurloe Head (27°37'31’N, 114°50' 37'’ W), outer coast of Baja California, Mexico (LACM 71-170, 13 - 20m, leg. J. H. McLean & P. LaFollette, R/V Searcher, October 23, 1971). There were many stations in between including collections at the offshore islands of San Geronimo (LACM 67-62), Sacramento Reef (LACM 71-91), San Martin (CASG 27600; LACM 67-60), Coro- nados (LACM 63-41; UCLA 22372 & 22383), San Nicolas (LACM 69-15), Catalina (UCLA 22319, 22381 & 22386; LACM 65-6; LACM-AHF 1359-41, 1381-41, 1399-46, 1426-41 & 1624-48; CASG 41308), Santa Rosa (LACM 73-9), Santa Cruz (LACM 63-5 & 73-11; LACM-AHF 1286-41), San Miguel (LACM 67-38) and Farallon (LACM 62-0). Bathymetrically, Lepidozona sinudentata has been found from intertidal to about 200 m (LACM-AHF 135 9- 41, ‘100-108 fathoms, on gray sand, 134 miles east of White Cove, Santa Catalina Island, Los Angeles, Califor- nia... June 13, 1941,” 1 specimen). Remarks: ‘The marked variability in Lepidozona sinu- dentata deserves emphasis. Interesting is the color phase “gallina” with its zebra-like appearance. Color variation in chitons is found in many species, but this particular zebra pattern is uncommon. However, it may be seen in two other species not immediately related: Ischnochiton petaloides (Gould, 1846) [=/. mariposa Dall, 1919] from the eastern Pacific and Ischnochiton zebrinus Bergenhayn, 1933 from the Sea of Japan. But the variations in sculpture, particularly of the lat- eral areas, should be stressed inasmuch as they may cause, and likely have caused, the false impression of distinct species. The deep water specimens may be particularly troublesome. It was only when, thanks to the kindness of Dr. James H. McLean, I had the opportunity of examin- ing material in the Allan Hancock Foundation Collec- tion, now with the Los Angeles Museum of Natural His- tory, from several deep-water stations in the general area of Catalina Island, Los Angeles County, California (LACM-AHF 1259-41, 1286-41, 1359-41, 1381-41, 1383- 41, 1426-41, 1399-46, 1624-48), that I realized the full THE VELIGER Page 31 scope of intraspecific variation in L. sinudentata, and was led to adopt an even broader view of the species than, under the auspices of A. G. Smith, I had anticipated. Lepidozona scabricostata (Carpenter, 1864) (Figures 7, 8, 24, 25) Ischnochiton (Lepidopleurus) scabricostatus CARPENTER, 1864b: 612 (Reprinted, 1872: 98), nomen nudum; A. G. SmiTH, 1977: 216, 234 - 235 Lepidopleurus scabricostatus CARPENTER 1864b: 649 (Re- printed, 1872: 135); 1866: 212; CoopEr, 1867: 22; Lowe, 1904: 19 [in error as “‘crebicostatus’’] Ischnochiton (Ischnochiton) scabricostatus, Pitssry, 1892, 14: 121; 1893, 15: 76, plt. 16, figs. 55, 56; DALL, 1921: 191; A. G. Smitn, 1947: 18 Ischnochiton scabricostatus, PiLsBry, 1896: 49 - 50; 1898: 288; Keep, 1904: 349; OLpRoyD, 1927: 276; PALMER, 1945: 101 [as “J. subexpressus Cpr. type =scabricostatus Cooper No. 518a...”]; 1958: 296; plt. go, figs. 10-12; Burc- HARDT & BURGHARDT, 1969: 18; ABBoTT, 1974: 395 Ischnochiton (Lepidozona) golischi BERRY, 1919, 2 (6): 7; 1925, 16 (5): 229-231; plt. 11, figs. 3, 4; A. G. SMITH, 1947: 18; A. G. SMiTH & Gorpon, 1948: 207 - 208 [in error for I. (L.) gallina Berry, 1925]; A. G. SmiTH, 1977: 216, 226 (syn. of L. scabricostata) Ischnochiton (Ischnochiton) golischi, DaLt, 1921: 192 (in section Lepzdozona) Ischnochiton golischi, OLDROYD, 1927: 284 (in section Lepi- dozona); TALMADGE, 1973: 232 Lepidozona golischt, BURGHARDT & BURGHARDT, 1969: 21 - 22; ApsorTrt, 1974: 306, fig. 4647 Lepidozona inefficax BERRY, 1963: 138; ABBoTT, 1974: 396 Nomenclatural Comments: CarPENTER’s (1864b) orig- inal description of Ischnochiton scabricostatus was both inadequate and confusing. PiLsBRy’s (1893, 15: 76; plt. 16, figs. 55, 56) redescribed and figured the species based upon the only specimen known at the time (USNM 16268). Still, the difficulties remained, and in collections specimens were often found labelled as Ischnochiton (Lepidozona) golischi Berry, 1919. Examination of the holotype of Isch- nochiton scabricostatus Carpenter, 1864, made avail- able through the courtesy of Dr. Joseph Rosewater, United States National Museum, Washington, D.C., solved conclusively the identification problem. A speci- men (ANSP 72128) subsequently reported and labelled as Ischnochiton scabricostatus by Pitssry (1898: 288) loaned for study through the kindness of Dr. Robert Rob- ertson, Academy of Natural Sciences, Philadelphia, con- firmed the correctness of its synonymy with the later- named J. golischi. The examination of the holotype of Ischnochiton (Lepidozona) golischi Berry, 1919, and the only extant paratype of Lepidozona inefficax Berry, 1963, made available through the generous hospitality and cour- Page 32 tesy of Dr. S. Stillman Berry, Redlands, California, Sep- tember 21, 1974, revealed their conspecificity with Lepr- dozona scabricostata. Diagnosis: Chitons of small size (up to about 2 cm), high arched. Color uniform, orange-brown to creamy-white. End valves and lateral areas display flattish radial ribs, neatly separated by sulci, and bearing a row of small round tubercles (often eroded away). Central areas with longi- tudinal riblets with a tendency to become beaded, and only faintly latticed. Girdle scales imbricated, moderately convex, shallowly striated. Type Material: Holotype (USNM 16268), figured in Pissry (1893, 15: plt. 16, figs. 55, 56) and PALMER (1958: plt. 30, figs. 10 - 21); color slides at CASIZ, Nos. 2974-77 (A. G. Smith), and 3119 (AJF). Other type material de- posited by Carpenter in the ‘State Collection, no. 1071 c’ [which refers to the old California State Collection] is presumed lost. Ischnochiton (Lepidozona) golischi Berry, 1919: “Type —An animal preserved dry [S.S.B. 1068], entered as Cat. No. 4093 of the author’s collection. A paratype [S.S.B. 1067] is the property of the Southwest Museum, Los An- geles.”’ (BERRY, 1925: 230). Lepidozona inefficax Berry, 1963: Holotype, ‘No. 28,712 Berry Collection’, has been lost (Dr. S. S. Berry, personal communication, Sept. 21, 1974). One paratype, still attached to the shell of the brachiopod Terebretalia, in the Berry Collection; color slides of the paratype at CASIZ, Nos. 3115-16 (AJF). Type Locality: ‘Catalina Island [California] 10-20 fms...” [18- 36m] (CARPENTER, 1866: 212). Description: The specimen [not figured here] is oval, high arched, carinated, uniformly brown in color. Fully extended, preserved in ethyl alcohol, it measures 21.5 mm in length (including girdle), 12.0mm in width, and 3.5 mm in height. Width/length ratio: 0.55. Jugal angle about 93°. The anterior valve displays about 40 flat radial ribs sep- arated from each other by a shallow sulcus, and bearing a row of small (about 100 ym in diameter) round tubercles. Most of these tubercles are missing, obviously eroded away; but it may be estimated that there would be about 12 per rib. The posterior valve shows about 30 of such tuberculated ribs in the post mucro area. The lateral areas of the intermediate valves are well defined; they bear 6 - 7 similar flat, tuberculated ribs, many of the tubercles miss- ing. Central areas have about 24 longitudinal riblets per side, with rather faint cross-ribbing; the longitudinal rib- lets tend to become obsolete towards the jugum, and often THE VELIGER Vol. 21; No. 1 are definitely granular, quasi-beaded. The jugal tract di- verges forwardly on valve ii, outlining a wedge-like figure. Mucro is moderately anterior. The gills, about 30 on each side, extend from about 1 mm in front of the anus to 2 mm behind the anterior bor- der of the foot. The girdle, about 1.5mm in width, is covered by imbricating, oval, flattish, scales, measuring as much as 220m in length, and displaying some 10- 12 shallow striations. The specimen, a topotype, was collected off Empire Landing, Catalina Island (33°26’N, 118°29’ W), Califor- nia, in 79m of water [43 fathoms] (CASIZ, leg. D. P. Ab- bott, Feb. 9, 1949, ex R. Stohler). Color slides at CASIZ, No. 590. A second specimen collected at 365 -'730m [200 - 400 fathoms] off Cordell Bank (38°03' N, 123°32/ W), Califor- nia (CASG 43983, USS Mulberry, station 56, March 29, 1950) is illustrated here (Figures 7, 8). A third specimen collected at 365 m [200 fathoms] off False Cape (40°31'N, 124°24'W), Humboldt County, California, (CASIZ, M/V Flicker, Sept. 1967, ex R. R. Talmadge) measures 22.9 mm in length, and was used for the study of the articulamentum, radula, and SEM micro- graphs of the girdle scales (Figures 24, 25). The articulamentum of this specimen is white. Sutural laminae are sharp and semioval, separated by a relatively shallow sinus. The sinus laminae are irregularly pecti- nated, and demarcated from the adjacent sutural laminae by a minute notch. Eaves are solid. The teeth are sharp edged and straight. Slit formula 12-1-11. The radula measures 8.4 mm in length, and has 38 rows of teeth. Radula relative length 37%. The median plate is enlarged anteriorly (130 ym), where it bears a thin blade recurved ventrally; it narrows medially but only moder- ately (to about 50um); posteriorly it bulges again (to about 80 um) in a spheroid. The intermediate plates have a knobby outgrowth at the outer-anterior corner. The uncinated plate is unicuspid; the blade measures about 180 um in length, the shaft 600 um. No tubercle is seen in the upper part of the shaft or the uncinated plate, nor in the radula of another specimen examined from the same station. Individual Variation: All specimens tend to be uni- formly colored. Some were an intense orange “‘Caledo- nian” brown, others a much lighter color, almost white. Variations in meristic characteristics are summarized in Table 1. The largest specimen examined measures, in- cluding the girdle, 24 mm in length (CASIZ, off Point Joe, Monterey Peninsula, Monterey County, California, in 110 - 130m of water [60 - 70 fathoms], leg. C. Jones, May 1941, ex Wilfred Mack Colln.). Vol. 21; No. 1 THE VELIGER Page 33 Table 1 Lepidozona — Lepidozona mertenstt cooper pectinulata (n=20) (n=20) (n=20) length (mm) 30-42 18-42 17-39 width (mm) 16-21 10-22 9-20 width/length ratio (mean) 0.59 0.57 0.58 jugal angle (mean) 93° 92° 99° Tegmentum: Valve i-ribs (no.) 21-40 15-24 16-35 (mean) ihe 21.0 24.5 Valves ii-vii central areas riblets (no.) 10-14 10-22 13-20 latticed? yes yes yes “wedge” on 11? yes yes yes lateral areas ribs (no.) 5-8 3-8 4-6 (mode) 6 5 4 (sculpture?) tubercles tubercles granular round elongated (200 um) Valves viii-ribs (no.) 11-23 15-20 12-30 (mean) 17.5 16.7 20.3 mucro? ant./cent. cent. cent. Articulamentum: Valve i-slits (no.) 8-12 9-15 10-15 (mode) 10 10 12 Valve viii-slits (no.) 8-11 9-14 10-17 (mode) 10 10 15 Girdle scales: flat-striated (S) or convex mammillated (M)? M S M maximum length (um) 500 500 400 Lepidozona Lepidozona Lepidozona Lepidozona Lepidozona — Lepidozona sinudentata — scabricostata willett retiporosa guadalupensis (n=20) (n=12) (n=10) (n=20) (n=12) 13-22 10-24 10-20 ~ Y/ 12-25 8-12 7-13 4-10 5-11 9-15 0.56 0.58 0.61 0.61 0.63 92° 98° 99° 99° 104° 18-29 32-50 20-40 20-30 12-26 22.5 40.0 29.8 25:5) 18.3 13-19 19-22 16-22 30-40 + 11-16 yes yes yes yes “pitted” yes yes yes yes no yes 3-5 4-7 4-7 3-6 3-6 4 5 5 5 4 granose tubercles tubercles tubercles tubercles (variably) round round round round (100 pm) (100 um) (80 um) (200 um) 12-27 25-40 15-28 15-20 13-20 16.8 30.0 21.0 ie -2 1 Sa cent. ant. ant. ant. ant./cent. 7-11 10-13 10-11 8-13 9-11 9 12 10 1] 11 7-11 11-14 9-11 8-12 9-11 9 1] 10 10 1] S S M S M 300 250 400 200 500 In some specimens the longitudinal riblets of the cen- tral areas are definitely granose to beaded. Some specimens display also what could be called growth lines in the form of transversal rugae particularly noticeable on valve ii. Distribution: Lepidozona scabricostata appears to have a continuous distribution between the latitudes 28° N and 48°N. The northernmost record is Cape Flattery (48°24.7'N, 126°06.2'W), Washington (LACM 72-140, FRB sta. 72-Q-3, at 274m, leg. D. Quayle, Feb. 1972). The southernmost record is that given by BERRY (1963) for L. “inefficax’’, Sebastian Vizcaino Bay (28°26.5/N, 114°36’W) Baja California, Mexico, at 55-57 fathoms [99 - 103m]. There are many stations between these ex- tremes. Although it has been found intertidally (LACM 63-53, Ensenada, Baja California, leg. J. H. McLean, Nov. 29, 1963, 12 specimens), L. scabricostata is confined to relatively deep water. Records from the offshore island are as follows: San Clemente (LACM-AHF 911-39, at 60 - 85 fathoms [108-153m]), San Nicolas (LACM-AHF 1345-41, at 57 fathoms [103 m]), Catalina LACM-AHF 3310-55, at 47-52 fathoms [85-94m]; UCLA 22403, at 40 fathoms [72 m]), Santa Rosa (LACM-AHF 1385-41, at 75-76 fathoms [135 - 137m]). Santa Cruz (LACM-AHF 1196-40, at 110 - 140 fathoms [198 - 252 m]), and Anacapa (LACM-AHF 874-38, 45 fathoms [81 m]). The greatest depth at which the species has been found is 1 260 - 1 460 m [690 - 800 fathoms] (CASG 43981, Mulberry Seamount, USS Mulberry station 38, February 13, 1950). Remarks: There is a great similarity between Lepido- zona scabricostata and L. willett: (Berry, 1917). The two species seem to agree in almost every respect except their radically different girdle scales. To make the matter all the more interesting, the two species are sympatric, often being found together in the same station, and exhibiting Page 34 exactly the same golden brown color. Both L. scabricos- tata and L. willetti differ from L. mertensii in several re- spects, above all by their girdle scales, the presence of sulci between the radial ribs, and the size of the tubercles on those ribs. From the examination of specimens of com- parable size, it was learned that the tubercles of L. scab- ricostata, as well as those of L. willetti, measure about 100 um in diameter whereas those of L. mertensii averaged 200 um in diameter. Lepidozona willetti (Berry, 1917) (Figures 9, 10, 30, 37) Ischnochiton (Lepidozona) willetti Berry, 1917: 232, 236 - 238, figs. 1, 2; A. G. Smitu, 1977: 216, 238 Ischnochiton willetti, WiLtetT, 1919: 27; OLpRoyp, 1924: 192 - 193; LARocQuE, 1953: 13 (in section Lepidozona) Ischnochiton (Ischnochiton) willetti, DALL, 1921: 192 (in sec- tion Lepidozona) Lepidozona willetti, BURGHARDT & BURGHARDT, 1969: 23; Assort, 1974: 395 Ischnochiton (Lepidozona) catalinae WILLETT, 1941: 185 - 186; plt. 31, fig. 2; A. G. SmiTH,1947: 18; A. G. SMITH & Gorpon, 1948: 207 [error in identification, A. G. Situ, 1977: 222]; A. G. Smitu, 1977: 216, 222 (syn. of L. willettt) Lepidozona catalinae, BURGHARDT & BURGHARDT, 1969: 20 - 21; AspgoTt, 1974: 396 Nomenclatural Comments: The conspecificity of Lepr- dozona willettt and L. catalinae was established through the examination and side by side comparison of type ma- terials of both nominal species, namely, L. willetti, para- type (UCLA 22314) available through the courtesy of Dr. W. P. Popenoe and Mrs. LouElla Saul, University of Cal- ifornia, Los Angeles; L. willetti virtual paratype (CASG 43991) through the cooperation of Dr. Peter U. Rodda, California Academy of Sciences, Department of Geology, San Francisco; and L. catalinae holotype (LACM 1063), through the kindness of Dr. James H. McLean, Los An- geles County Museum of Natural History, Les Angeles, California. Diagnosis: Chitons of medium size (up to 3cm), oval, high arched. Uniformly colored reddish-brown. End valves and lateral areas show flattish radial ribs separated by sulci, and bearing small round tubercles. Central areas with longitudinal riblets, often faintly beaded, and weakly latticed. Mucro is anterior. Girdle with imbricated, strongly convex scales bearing a rather long, striated, mamumnilla. THE VELIGER Vol. 21; No. 1 Type Material: Holotype —- “A shell preserved dry [S.S.B 159] as Cat. No. 3700 in the author’s collection”. (BERRY, 1917: 238). Paratypes — “‘... in the collections of the California Academy of Sciences [CASG 1123], the Academy of Natural Sciences of Philadelphia [ANSP 117530], the United States National Museum [USNM 217936], and the private collection of Mr. George Willett [UCLA 22314] (BERRY, l.c.). Ischnochiton (Lepidozona) catalinae Willett, 1941: Holotype (LACM 1063). Paratypes (UCLA 22320 ex G. Willett Colln.; LACM 1000; CASG 10263 ex A. G. Smith Colln.; ANSP 117536). Type Locality: “15-20 fathoms [27 - 36m], Forrester Island, Alaska; George Willett, May-July-August, 1914 - 1916; 36 specimens.” (BERRY, l.c.) Description: BeErry’s (1917) original description and figuring is perfectly adequate to define and understand the species. The photographed specimen (Figures 9, ro) is a para- type (CASG 1123). Color slide at CASIZ, No. 3101 (AJF). It shows that the longitudinal riblets in the central area remain parallel to the jugum or even display a mild ten- dency to converge forwardly. However, the jugal tract supersedes them on valve 11 where it diverges forward widely forming a wedge-like figure. The tubercles of the radial ribs measure about 100- 150ym in diameter and height. The girdle scales, strongly convex and with long nipples measure a maximum of 270m in length. Mucro is anterior. Another specimen (SDNH 23505), a topotype, was used for color slides of the girdle scales, now at CASIZ, Nos. 3126-27 (AJF). A third specimen was used to obtain SEM micrographs of the girdle scales (Figures 30, 31), and study of the rad- ula. The specimen, dried but fully extended measures 16.5 mm in length (CASG 32536, San Pedro, California, San Diego Marine Biology Association sta. no. XXI-2, at 79- 140m, June 20, 1901). Slit formula 10-1-10. The radula of this specimen measures 6.3 mm in length, and has 38 rows of teeth. Relative length 38%. The me- dian plate is wide anteriorly (140um) with a thin blade that recurves ventrally; the plate narrows medially (to 50 um) and then bulges posteriorly (to 80 um) to terminate abruptly in a point. The intermediate plate shows a knobby outgrowth on the outer-anterior corner. The un- cinated plate is unicuspid; the blade is about 250m in length, the shaft 500 ym. A tubercle is discernible on the Vol. 21; No. 1 THE VELIGER Page 35 upper part of the shaft, immediately below the blade, pointing inwardly. Individual Variation: Variations in meristic characteris- tics are summarized in Table 1. It is noteworthy that all specimens examined were of a very constant reddish- brown color, uniform throughout, and practically with no markings. Only two specimens showed a small dark brown triangular marking at the jugum; and one speci- men was a light tan color, vaguely splashed with cream- white. The largest specimen examined measures 28.0 mm in length (including girdle); the largest specimen reported is 29.5 mm long (BERRY, 1917). Distribution: Lepidozona willetti seems to have a con- tinuous distribution between latitudes 26° N and 54°N. The northernmost record is Forrester Island (54°48’N, 133°32' W), Alaska (Type locality); the southernmost rec- ord is 29 miles [46.4 km] south of Punta Abreojos (26°16' 24""N, 113°41'/18” W) Baja California, Mexico (LACM- AHF 1710-49, at 54 fathoms [99m], March 7, 1949). The species was collected at many stations between these two extreme points, including Catalina Island (LACM 65-7, 1000, 1063; SDNH41430; UCLA 22320), Anacapa Island (LACM-AHF 875-38), and Forrester Island (CASG 43991; SDNH 23505; UCLA 22314). It definitely favors relatively deep water with no record of having been found intertidally; the bathymetric range of the examined speci- mens that had it noted is 13 - 40m [40 - 125 feet] (LACM 60-24, Carmel Submarine Canyon, north end of San Jose Creek, Monterey County, Calif., Jeg. J. H. McLean, 1960 - 1964) to 274m, west of Cape Flattery (48°24’N, 126°06’ W) Washington (LACM-AHF 72-140, leg. D. Quayle, FRB sta. t2-Q-3, Feb. 1972). Remarks: Lepidozona willetti has been found together with L. mertensti (BERRY, 1917); however, as mentioned before it is most often found together with L. scabricostata with which it shares a great portion (if not all) of its bathy- metric and geographic range. A color slide of the two spe- cies, side by side, is in CASIZ, No. 3113 (AJF), emphasiz- ing their great morphological and color similarity. Lepidozona retiporosa (Carpenter, 1864) (Figures 11, 12, 26, 27) Ischnochiton (Trachydermon) retiporosus CARPENTER, 1864b: 603 (Reprinted, 1872: 89), nomen nudum; tbid., 649 (Reprinted, 1872: 135); 1865: 59-60; PitsBry, 1892, 14: 75; A. G. SmitH, 1977: 216, 233 Trachydermon retiporosus, COOPER, 1867: 22 Ischnochiton retiporosus, Pitspry, 1893: 77; plt. 16, figs. 47, 50-53 [in error as “‘reteporosus’’]; KEEP, 1904: 349 [as “reteporosus’|; WILLETT, 1919: 27; OLDROYD, 1924: 190 - 191; 1927: 272-273 (in section Stenoradsia); Burcu, 1942: 7; LaRocaguE, 1953: 13 (in section Stenoradsia); BURGHARDT & BURGHARDT, 1969: 17 - 18, 43; plt. 2, fig. 21 (in color); Kurs, 1974: 366; Apporr, 1974: 395 Ischnochiton (Ischnochiton) retiporosus, DALL, 1921: 191 Ischnochiton (Lepidozona) retiporosus, Berry, 1917: 231, 235 - 236; 1927: 164; A. G. Smitn, 1947: 18; A. G. Smrtu & Gorbon, 1948: 208; PALMER, 1958: 275; plt. 30, fig. 7; pit. 35, figs. 4, 5 Lepidozona retiporosa, CARLISLE, 1969: 241 Leptochiton punctatus WHITEAVES, 1887 Ischnochiton veneztus DALL, 1919: 509; BURGHARDT & Burc- HARDT, 1969: 18; ABBott, 1974: 395; A. G. Smitu, 1977: 216, 237 - 238 (syn. of L. retiporosa) Ischnochiton (Ischnochiton) venezius, DALL, 1921: 191; OLp- ROYD, 1927: 274; A. G. SmitH, 1947: 18 Ischnochiton (Ischnochiton) aureotinctus Carpenter MS, Pirspry, 1892, 14: 123; DaLi, 1921: 191; A. G. SmitTH, 1977: 216, 220 (as nomen inquirendum) Ischnochiton aureotinctus, KEEP, 1904: 349; OLDROYD, 1927: 276 - 277; PALMER, 1945: 101; BURGHARDT & BURGHARDT, 1969: 16 Ischnochiton (Lepidozona) aureotinctus, A. G. Smit, 1947: 18; PALMER, 1958: 272, plt. 31, figs. 1-4 Nomenclatural Comments: The examination of the holotype of Ischnochiton venezius Dall, 1919, available through the courtesy of Dr. Joseph Rosewater, United States Museum of Natural History, Washington, D.C., revealed its conspecificity with Lepidozona retiporosa as suspected by BURGHARDT & BURGHARDT (1969) and con- firmed by A. G. SMITH (1977). The synonymization of Ischnochiton (Ischnochiton) aureotinctus Carpenter in Pilsbry, 1892 was not an easy matter. Examination of the the holotype, kindly loaned by Dr. Vincent Condé, Redpath Museum, Montreal, Can- ada, first led to the conclusion that this nominal species should remain as a nomen inquirendum pending the availability of more and better material A. G. SmiTH (1977). The desideratum has now been fulfilled in the form of several lots from deep water in the Allan Hancock Foundation Collection, now at the Los Angeles County Museum of Natural History, available through the gener- ous cooperation of Dr. James H. McLean. The material contained several specimens that revealed the intergrada- tion of J. aureotinctus with L. retiporosa, and establishes their conspecificity. Diagnosis: Chiton small (up to 1.5.cm), color uniform, often ashen-brown. End valves and lateral areas show ill- defined radial ribs bearing a row of minute tubercles (often eroded away). Central areas punctated to pitted. Page 36 Mucro anterior. Girdle scales closely imbricated, small, elongated, striated. Type Material: Holotype (USNM 4499). Color slide of the specimen at CASIZ, No. 2045 (A. G. Smith). Ischnochiton venezius Dall, 1919: Holotype (USNM 216792). Color slides at CASIZ, Nos. 2966-67 (A. G. Smith), and 3123-24 (AJF). Ischnochiton (Ischnochiton) aureotinctus Carpenter in Pilsbry, 1892: Holotype (Redpath Museum no. 26). Color slide of the specimen, CASIZ, No. 3088 (A. G. Smith). Type Locality: Puget Sound, Washington, ‘specimen unicum legit Kennerley’’ (Carpenter, 1865: 59). Description: The specimen (Figures 71, 12) is oval, high arched, of a dusty brown color. Dried but fully extended, it measures 13.0mm in length, 8.2 mm in width, and 2.8 mm in height. Width/length ratio: 0:63. Jugal angle about 98°. The anterior valve shows some go radial ribs, quasi- obsolete, almost undefined except for the row of minute tubercles which they bear. These tubercles, most of which have fallen off, are neatly round, and measure about 80 um in diameter and height. Allowing for those that must have fallen off, it is estimated that there would be about 10 such tubercles per rib. Similar sculpture is found in the post-mucro area of the posterior valve; only here the ribs are even less defined, and a reasonable count could not be obtained. The mucro of the posterior valve is well marked, slightly beaked, and definitely anterior. The in- termediate valves show fairly raised and demarcated lat- eral areas bearing similar tuberculated ribs, about 5 - 6 ribs per lateral area. It must be stated that the radial ribs are only virtual, i.e., not defined by any feature, such as sulci or undulations of the tegmentum, other than the presence of the minute tubercles. The central areas are punctated to pitted, but become rather granulose at the jugum; in the pleural areas it becomes apparent that the pitted appearance is the result of the intercrossing of lon- gitudinal and transversal riblets, an accentuated case of latticing. No wedge-like figure is found on valve ii. The articulamentum is creamy white. Sutural laminae are rather short, and semioval. Sinus is shallow; sinus lam- inae with minute, irregular pectinations, occasionally notched at their junction with the sutural laminae. Eaves are solid. Insertion teeth are sharp and straight edged. Slit formula 12-1-11. The girdle is densely covered with imbricating elon- gated scales, about 150um in length by 7oum in width. The scales have 8 - 10 striations, which are minutely punc- tated, a feature particularly visible in SEM micrographs (Figures 26, 27). The specimen, a topotype, was collected THE VELIGER Vol. 21; No. 1 at 48m Puget Sound, Washington (CASG 43840, leg. T. S. Oldroyd, ex Gordon Colln.). A second specimen (CASG 36334, off San Pedro, Calif., San Diego Marine Biological Association sta. XXIIL2, June 22, 1901), collected in 42-55 m, was used for the study of the radula. The specimen measures 11.0mm in length. The radula measures 4.2 mm, and has 37 rows of teeth. Radula relative length 38%. The median plate is wide anteriorly (80 pm) bearing a thin blade that recurves ventrally; the plate narrows medially (to about 40um), and bulges modestly (to about 50 um) posteriorly. The uncinated plate is unicuspid; the blade measures about 80 um in length, the shaft 140 um. In the upper part of the uncinated plate, immediately underneath the blade a tubercle, about 50m x 10m points inwardly. Individual Variation: In coloration, Lepidozona rett- porosa varies relatively little; it usually remains in tones of brown, occasionally being tan or apricot color. Girdle is usually the color of the tegmentum, and only occasion- ally banded. In sculpture, there is some observable varia- tion in the number of tubercles present in the lateral areas and end valves. Some specimens may have very few tubercles, even none, making identification rather diffh- cult and tentative. For whenever the tubercles are absent (which may be the result of erosion; or, in juvenile speci- ments, in which the tubercles might not yet have ap- peared ?) the lateral areas look rather smooth since the radial “‘ribs’”’ are virtual; in such instances the other char- acteristics of the species, notably its girdle scales, the pitted appearance of the central areas (not always clearly present, either, particularly in juvenile specimens), and the an- terior mucro may help in identification. Variations in meristic characteristics are summarized in Table 1, based upon a sample of g0 adult-looking speci- mens from several geographical sites. In size, the largest specimen examined measures 17.0 mm in length, including girdle (CASG 43980). Distribution: The known range of Lepidozona retipo- rosa extends between latitudes 23° N and 55° N, from in- tertidal in the northern part of the range to considerable depths in the southern areas. The northernmost record is Edna Bay (55°57'N, 133°40’ W), Kosciusko Id., Alaska, (CASIZ, leg. G. D. Hanna, intertidal, July 1947). Until recently the southernmost record had been placed around San Diego, California; but dredging along the outer coast of Baja California, Mexico has shown that, at consider- able depths, L. retiporosa is to be found much farther south, and that its range extends south at least to the tip of Baja California (23°45/N, 111°55/ W) (KuEs, 1974). The known bathymetric ranges extend from intertidal to 6go - 800 fathoms [1262 - 1463] (CASG 33036, Mul- Vol. 21; No. 1 berry Seamount, USS Mulberry sta. 38, leg. G. D. Hanna, February 13, 1950). Between the two extreme points of its range, the species has been collected at many stations, notably at Catalina Island (CASG 43988; LACM A.199 & HH.1052; LACM- AHF 999-39, 1399-41, 1426-41), Vancouver Island (CASG 37544; LACM 37-2, 73-40, 73-43), Hope Id. (LACM 63-62), Jessie Island (LACM A.8881.66). Remarks: The characteristically “pitted” appearance of the central areas makes L. retiporosa quite unique among the Lepidozona in the eastern Pacific. The species is sym- patric with L. scabricostata and L. willetti to the point that the 3 species are often seen together at the same col- lecting station. Interestingly, they often share exactly the same color. Lepidozona guadalupensis Ferreira, spec. nov. (Figures 13, 14, 32, 33) “Ischnochiton mertensi (Middendorff)’, Crace, 1958: 331 {not Lepidozona mertensii (Middendorff, 1847)] “Lepidozona mertens: (Middendorff, 1846)”, A. G. Smitu, 1963 (4): 148 [not Lepidozona mertensii (Middendorff, 1847)] Diagnosis: Medium size chitons (up to 3cm). Color in tones of red, and orange-brown, often variegated. End valves and lateral areas with radial ribs separated by well defined sulci, and bearing a row of well-formed, round, tubercles. Central areas with longitudinal riblets, cross- ribbed. Girdle scales imbricated, strongly convex, nip- pled, and with very minute rows of granules on their outer faces. Description: Holotype — Dried but fully extended, it measures (including the girdle) 22.0mm in length, 14.0 mm in width, and 3.6 mm in height. Width/length ratio: 0.63. Jugal angle about 103°. The tegmentum has a predominantly pink color mixed with light tan and brown; the surface is microgranular. The anterior valve shows some 14 radial ribs bearing 8 - 12 (some eroded away) round and well defined tuber- cles about 200 um in diameter and height. Each radial rib is clearly separated from adjacent ones by sulci marked by a row of minute and somewhat irregular pits. The post- mucro area of the posterior valve has similar radial ribs, about 14 in number. The lateral areas of the intermediate valves are moderately raised, and show about 5, - 6 similar radial tuberculated ribs. The central areas display longi- tudinal riblets about 12-14 per side, cross-ribbed; the longitudinal riblets become progressively crowded to- wards the jugum. The jugum is also ribbed longitudi- THE VELIGER Page 37 nally, and shows cross ribbing although not as clearly as in the pleural areas. The jugal tract tends to diverge for- wardly, particularly on valve 11 where it forms a wedge- like figure. This wedge figure shows cross-ribbing, too. In the posterior valve, the mucro is anterior, but not con- spicuous. The articulamentum is white. Sutural laminae are sub- quadrate and relatively short, separated by a well defined sinus. Sinus laminae show a few minute, irregular pectina- tions, and are demarcated from the adjacent sutural lam- inae by a small notch. The eaves are solid. The insertion teeth are relatively small, sharp, straight edged. Slit formula g-1-11. The girdle is distinctly banded pink and tan. The girdle scales are large (up to 500 ym), strongly convex, and often bearing a nipple. SEM micrographs of the girdle scales (Figures 32, 33) show this nipple to be striated; they show further that the outer surface of the scales bear transversal rows of minute pustules which, when seen under ordinary magnifications, may give an impression of striation. The radula measures 8.0 mm in length, and has 35, rows of teeth. Its relative length is 36%. The median plate is wide anteriorly (170m) with a thin blade recurved ven- trally; the plate narrows medially (to 50ym) and then bulges posteriorly (to 80m) in a spheroid that seems to end in two points separated by a notch. The intermediate plate has a knobby outgrowth on the outer-anterior cor- ner. The uncinated plate is unicuspid; the blade is about 250um, the shaft 500 um. In the upper part of the shaft, underneath the blade, a tubercle is present, pointing inwardly. The specimen here designated as holotype was collected at Northeast Anchorage (29°11’N; 118°17’W), Guada- lupe Island, Baja California, Mexico, December go, 1974, in about 0.5 m of water, at low tide, on the undersurface of a small movable rock, leg. W. L. Lee & A. J. Ferreira (AJF 210) as part of a lot of four specimens. One of these specimens, a paratype, 25 mm in length is illustrated (Figures 13, 14). Type Material: In addition to the holotype, and 3 para- types from the same station, a lot of 15 other specimens, collected during the same trip to Guadalupe Island, at Sealers’ Camp (29°01’N; 118°13’W), also at low tide, under rocks (AJF 211, leg. W. L. Lee & A. J. Ferreira, January 1 - 2, 1975) are also designated here as paratypes. Holotype (disarticulated valves, mounted radula, and mounted girdle scales) is deposited in the California Acad- emy of Sciences (CASIZ, Type Series No. 703), together with 6 paratypes (CASIZ, Type Series Nos. 704). Color slides of the type material are at CASIZ, Color Slide Series. Paratypes have also been deposited with the Los Angeles County Museum of Natural History (LACM 1857), San Page 38 THE VELIGER Vol. 21; No. 1 Diego Museum of Natural History (SDNH 68728), United States National Museum of Natural History (USNM 770960), Academy of Natural Sciences, Phila- delphia (ANSP A7226), and the American Museum of Natural History (AMNH 183855). Type Locality: Northeast Anchorage (29°11'N; 118° 17'W), Guadalupe Island, Baja California, Mexico, where 4 specimens, including the here designated holo- type, were collected, December 30, 1974, by Dr. Welton L. Lee and myself. Distribution: In addition to the 2 type lots mentioned above, the following collections came to my attention, all from Guadalupe Island: CASIZ 32746, intertidal, stas. M-25-A & M-25-C, south end of Guadalupe Id., leg. M. Woodbridge Williams, July 1946, [misidentified as Lepi- dozona mertensii] 27 specimens; SDNH 9957, leg. C. L. Hubbs et al.{misidentified as L. mertensit] 2 specimens; LACM 65-41, at 20 feet [6m], West Anchorage (28°58.5' N; 118°18/ W), leg. L. Thomas & B. Owen, Oct. 1975, 22 specimens; LACM-AHF 1912-49, intertidal, Melpomene Cove (28°52'05’N, 118°19'05"’ W), Dec. 17, 1949, 1 spe- cimen; LACM-AHF 1293-49, intertidal, 214 miles [4 km] north of South Bluff (28°54’N; 118°16’W), Dec. 19, 1949, 2 specimens; LACM-AHF 1925-49, 35 - 40 fathoms [54- 73m], 214 miles [4 km] from South Bluff (28°53'44” N; 118°15'35’’ W), Dec. 20, 1949, 2 specimens. From these collections, it seems that the species is endemic to Guada- lupe Island, and has a bathymetric range from intertidal to about 70m. Individual Variation: Lepidozona guadalupensis dis- plays only moderate variation in color; the pinks and the browns predominate, often in a variegated combination where some splashes of white may also be seen. A common color pattern is that of blotches of dark brown along the pleural areas on a rose-pink background. The double (or single) transversal bands of light color so commonly seen in L. mertensii were not observed in any of the specimens examined. In size, Lepidozona guadalupensis seems to be smaller on average than its sibling species, L. mertensi. The larg- est specimen of L. guadalupensis measures, including gir- dle, 31.0mm in length (CASIZ 32746). Variations in other meristic characteristics are summarized in Table 1. Remarks: Lepidozona guadalupensis bears a very close resemblance to L. mertensit with which it could be easily confused. However, the 2 species differ in their average size, general color, the presence (or absence) of sulci de- fining the radial ribs on the end valves and lateral areas, and the ornamentations of the girdle scales. Still, their resemblance is such that, at one point in this study, the appropriateness of making L. guadalupensis simply a sub- species of L. mertensii was seriously considered. In its relatively remote position, Guadalupe Island is a true oceanic island that has never been connected with other shores; it is the top of a volcanic mountain that rises some 3600 m from the surrounding ocean floor. It is tempt- ing to speculate that L. guadalupensis evolved from L. mertensit under the conditions of geographic isolation that characterize Guadalupe Island. But while the larvae of L. mertensit, having reached the Island from the Main- land, evolved and speciated into L. guadalupensis, it is intriguing to realize that a similar phenomenon of dif- ferentiation and speciation did not affect other species which reached Guadalupe Island by similar means, and conceivably at the same time. Populations of Cyanoplax hartwegiu (Carpenter, 1855), Callistochiton palmulatus Dall, 1879, and Nuttallina californica (Reeve, 1847) among others (A. G. SmrrH, 1963) known on the Island remain identical to their stocks of origin on the Mainland. Radiometric dating places the age of Guadalupe Island at about 7 million years (HusBs, 1967), and so fixes the maximum age of Lepidozona guadalupensis. Fossil Record: In pleistocene material from Guadalupe Island made available to me through the courtesy of Dave R. Lindberg and Barry Roth, California Academy of Sci- ences, I have identified three intermediate valves of the species here described as Lepidozona guadalupensis. In the same deposit, 3 valves of Nuttallina californica, and 1 valve of Callistochiton palmulatus were also found. Corals from this deposit (SDNH Loc. * 0641: coquina sample taken from E side near south end of Islote Negro, on west coast of Guadalupe Island, at about 3 to 6m above sea level, C. L. Hubbs, April 19, 1957) have been radiomet- rically dated at between 110,000 and 130,000 years before present (GOLDBERG, 1965). Discussion A number of other eastern Pacific species of chitons have been referred, albeit tentatively, to the genus Lepidozona: Ischnochiton stearnsu Dall, 1902: Holotype (USNM 109024), collected off Farallon Islands, California, in 391 fathoms [715m] was examined thanks to the courtesy of Dr. Joseph Rosewater. Another specimen (LACM 65-4), off Catalina Island, California, 250 fathoms [475 m] was examined through the generosity of Dr. James H. Mc- Lean. Recently, the study of material in the collection of the Allan Hancock Foundation, now at the Los Angeles Museum of Natural History, revealed two more speci- mens of I. stearnsit, one off San Clemente Island, 250 - 300 fathoms [475-549m] (LACM-AHF 1019-39), another Vol. 21; No. 1 found near Catalina Island, in 240-250 fathoms [439 - 457m] (LACM-AHF 2004-50). The presence of g slits in some of the intermediate valves, and the spiculoid girdle scales exclude J. stearnsit from Lepidozona. The species appears to belong to the same species-group as I. abyssicola A. G. Smith & Cowan, 1966, and perhaps J. acelidotus Dall, 1919 [=J. exanthematus Dall, 1919] as suggested by A. G. SmitH & Cowan (1966: 14-15), and A. G. Smitu (1977: 218 - 219). Whether or not a new genus may have to be erected to accommodate these species is a matter for future consideration. Color slides of the holotype of J. stearnsit at CASIZ, Nos. 1030-33, 1046, 1070, 2050-51 (A. G. Smith), and 3120-22 (AJF). Ischnochiton (Lepidozona) asthenes Berry, 1919: Col- lected intertidally at White’s Point (Type locality), Los Angeles County, California (CASG 439180), Coronados Islands (SDNH 53867), and Guadalupe Island (CASG 32746) Mexico, the species belongs in the genus Callisto- chiton Dall, 1879, on account of the bicostate lateral areas, radial undulations (instead of “ribs”) of the end valves and lateral areas, minute girdle scales and slits that correspond in number and position to the undu- lations of the tegmentum. Ischnochiton veredentiens Carpenter, 1864: Holotype (USNM 16259), from ‘Catalina Island’, California, ex- amined through the courtesy of Dr. Joseph Rosewater, is reduced to only 6 disarticulated valves (to which bits of glue adhere) and dried soft parts. The girdle is missing. The lateral areas have two granulose radial ribs; the cen- tral areas, longitudinal riblets, latticed. The mucro is cen- tral. This small specimen (perhaps 6 to 7 mm long, if in- tact) looks like a member of the genus Lepidozona. Al- though I am inclined to the belief that the specimen is a juvenile of Lepidozona sinudentata, species assignment is unwarranted, under the circumstances, and the name should be considered as a nomen inquirendum (A. G. SMITH, 1977: 216, 238). Color slides of the holotype are CASIZ, Nos. 2978 (A. G. Smith), and 3125 (AJF). Ischnochiton (Ischnochiton) newcombi Carpenter in Pilsbry, 1892: Holotype (Redpath Museum no. 19) ex- amined through the generosity of Dr. Vincent Condé. This is a small specimen (about 9 mm long) whose valves i, vil, viii are broken into small but still identifiable frag- ments. Central areas have a granular surface; lateral areas have some 4 radial ribs bearing coarse, irregular, low tu- bercles. As PirsBry (1892: 120) noted, the specimen “‘re- sembles that of J. interstinctus though coarser and dif- ferent in detail.” Although not a likely member of the genus Lepidozona, the species must be regarded for the moment as valid (A. G. SMITH, 1977: 228-229). Color slides, CASIZ, Nos. 3089-91 (A. G. Smith), and 3083-85, (AJF). THE VELIGER Page 39 The genus Lepidozona seems to be confined to the north Pacific. It is not reported in the Caribbean (Kaas, 1972), in the Mediterranean (SABELLI, 1974), or other European waters (Richard Van Belle, in litt. March 23, 1975). On the other hand, the list of Japanese species is long: Lepidozona coreanica (Reeve, 1847) [= L. pectinella Bergenhayn, 1933, fide Isao Tak1, 1938]: L. tyoensis (Is. Taki & Iw. Taki, 1929); L. amabilis (Berry, 1917); L. interfossa (Berry, 1917); L. sahlini Bergenhayn, 1933; L. pallida Bergenhayn, 1933. Although I have had no oppor- tunity of examining representatives of most of these spe- cies, it seems from the descriptions given that these may in fact belong to the genus Lepidozona. All of these nom- inal species have uni-slitted intermediate valves. However, another group of North Pacific species often referred to Lepidozona should be given a different generic assignment on account of their radsioid, i.e., two-slitted intermediate valves: Chiton albrechti Schrenck, 1867; Ischnochiton (Lepidozona) nipponica Berry, 1918 [new name for Ischnochiton (Lepidozona) pilsbryanus Berry, 1917 (not Ischnochiton pilsbryanus Bednall, 1896); =Lepidozona pilsbryana Is. Taki, 1938; Ischnochiton (Lepidozona) berryanus Leloup, 1941]; Ischnochiton bi- sculptus Carpenter in Pilsbry, 1892 [considered uni-slitted by Pilsbry (1892: 119) but found to be two-slitted by Leloup (1941: 5)]; Gurjanovillia lindberghi Jakovleva, 1952 [= G. derjugini Jakovleva, 1952, fide Sirenko, 1975]; Lepidozona multigranosa Sirenko, 1975; Lepidozona thiele: Sirenko, 1975; Lepidozona ima Sirenko, 1975. The appropriate generic assignment of these species cannot be decided at this time. Conceivably, they may be referred to the genus Gurjanovillia Jakovleva, 1952, now removed from the synonymy of Lepidozona Pilsbry, 1892 (FER- REIRA, 1977: 28 - 29). The matter awaits further study. In the Indo-Pacific the genus Lepidozona is not known, except perhaps for one species from the Java Sea, Callisto- chiton finschi Thiele, 1910 [=C. recens Thiele, 1911] which IREDALE & HULL (1925, 4: 354 - 355) referred to the genus Solivaga Iredale & Hull, 1925, now synonymized under Lepidozona (A. G. SMITH, 1960; FERREIRA, 1974). In the eastern Pacific, 14 species of Lepidozona are now recognized, 6 from the Tropical Region (FERREIRA, 1974), and 8, herein, from the northern Temperate Region. Whether the genus Lepidozona is present (or absent) from the southern Temperate Region of the eastern Pacific is an open question pending better knowledge of the South American fauna. It is not known in the Galapagos Islands (A. G. SMITH & FERREIRA, 1977). The geographic range of the eastern Pacific species of Lepidozona, as presently known, is summarized graphi- cally in Diagram 1 which illustrates well the faunal break known to occur at about Magdalena Bay in Baja Califor- No. 1 p) Vol. 21 THE VELIGER Page 40 60° - Sitka 50° Vancouver 40° - Pt. Conception VU LLL MM LLELL LA YEA Z - - - Cabo San Lucas S|SODMARB[EAQIVAVVAS 20° 10° Panama Pe ~sQcssy qyjiwsudyo DuOozopIg aT DIDLY1D1I DUoZOpigaT DjDs4Las DuozopigaT sytaqns DuozopigaT Dsowusof DuozopigaT 249Y9049 DUOZOpidaT 0504091394 DUOZOpIgaT usuajlau DUuozopigaT wyayim DuozopigaT D4DjSOILQDIS DUOZOpIgaT 149G002 DuozopigaT Dyojnurj2ag DuozopidaT DioJuapnuts DuozopidaT sisuagnppona vuozopidaT epnyneyT Diagram 1 Geographical Distribution of the Species of Lepidozona Pilsbry, 1892 in the Northeastern Pacific Vol. 21; No. 1 nia (Briccs, 1974). Lepidozona serrata (Carpenter, 1864) has been collected at Magdalena Bay, Baja California (leg. H. N. Lowe, December 1931, SDNHM 23622), San Diego (DALL, 1921), and Monterey Bay, California (FERREIRA, 1974); but these findings seem to be freakish events which have remained uncorroborated by the same or other col- lectors. Thus, Lepidozona serrata cannot be considered a normal component of the chiton fauna of the North Tem- perate Eastern Pacific. It is worth noting that, in this work, the study of the radula proved to be very unproductive. Despite the prom- ises embodied in the works of THIELE (1893), JAKOVLEVA (1952) and others, in my experience the radula of chitons has not yielded significant means of distinguishing most species, genera, or even families. This is certainly the case with the species of Lepidozona in this study whose radulae are, except for size, practically identical. Thus, to avoid uninformative redundancy, only the radula of L. merten- sti is illustrated (Figure 34). THE VELIGER Page 41 By contrast, the study of the girdle scales, greatly im- proved by the advent of SEM microphotographs, has pro- vided most valuable information. As a taxonomic char- acter, among all the features that distinguish the individ- ual species of Lepzdozona, the girdle scales have appeared most reliable for their uniqueness and constancy. Even in the case of juvenile specimens, much before the appear- ance of characteristic tegmental sculpture, the girdle scales can lead, often with assurance, to the identification of the species in question. The particular significance of the girdle scales in Lepi- dozona was anticipated by Pitspry (1893) with the sug- gestion of two groupings, the L. mertensii group of spe- cies with strongly convex, mostly smooth, nippled scales, and the L. coreanica group of species with flattish, striated scales. Within this scheme, a phylogenetic tree of the spe- cies of Lepidozona in the North Temperate Region of the eastern Pacific is proposed in Diagram 2 (cf. FERREIRA, 1974). Lepidozona mertensii Lepidozona guadalupensis Lepidozona mertensu group Lepidozona willetti Lepidozona pectinulata Lepidozona sinudentata Lepidozona coopert Lepidozona coreanica group Lepidozona retiporosa Lepidozona scabricostata Diagram 2 Tentative Phylogenetic Tree of the Genus Lepidozona Pilsbry, 1892, in the North Temperate Region of the Eastern Pacific ACKNOWLEDGMENTS I want to express my appreciation to all who made their museum and personal chiton collections available to me, and in particular to Dustin Chivers, Dr. Welton L. Lee, Barry Roth, and Dr. Peter U. Rodda of the California Academy of Sciences; Dr. James H. McLean, and Gale Sphon of the Los Angeles County Museum of Natural History; Dr. Robert Robertson of the Academy of Nat- ural Sciences of Philadelphia; Dr. Joseph Rosewater of the U.S. National Museum of Natural History; Dr. George E. Radwin of the San Diego Museum of Natural Page 42 THE VELIGER Vol. 21; No. 1 History; Dr. LouElla Saul and Dr. W. P. Popenoe of the Department of Geology of the University of California at Los Angeles; Dr. Victor Condé, Redpath Museum, Montreal, Canada; Dr. S. Stillman Berry, Redlands, Cali- fornia; John H. Himmelman, University of British Co- lumbia; Col. George A. Hanselman, San Diego, Califor- nia; Mrs. Salle Crittenden, San Francisco, California; Glenn & Laura Burghardt, San Leandro, California; Dr. I. McTaggart Cowan, University of British Columbia, Vancouver, Canada; and Dr. Iwao Taki, Professor Emeri- tus of Hiroshima University, Kyoto, Japan. Very special thanks are due to Dr. Hans Bertsch, Cha- minade University, Hawaii, formerly with the Donner Laboratory, University of California, Berkeley, for much good advice and the SEM micrographs of the chiton spe- cimens; to Dr. Paul O. Weiss and Dr. Robert Melnikoff, San Jose, California, for their efforts in translating Ger- man and Russian works; and to Dr. Peter U. Rodda, De- partment of Geology, California Academy of Sciences for critical reading of the manuscript, and most generous help in elucidating the taxonomic questions involved in this study. Finally, a profoundly felt appreciation to the late Allyn G. Smith, who piloted my steps in this work with his data, ideas and wisdom. Literature Cited Aszoit, Rosert Tucker 1954. American seashells. Princeton, New Jersey. D. van Nost- rand Co., Inc.; xiv+541 pp.; 40 plts.; 100 text figs. 1974. American seashells. and ed.; 663 pp; 4000+ figs.; plts. 1 - 24 (in color). Van Nostrand Reinhold Co., New York AnpbrREws, Harry L. 1945. The kelp beds of the Monterey region. Ecology 26 (1): 24-37 (January 1945) Berry, SAMUEL STILLMAN 1907. Molluscan fauna of Monterey Bay, California. The Nautilus 21 (2): 17-22; 21 (3): 34-35; 21 (4): 39-47; 21 (5): 51-52 (21 June to 18 September 1907) 1917a. | Notes on west American chitons. I. Proc. California Acad Sci., (4) 7 (10): 229-248; 4 text figs. (1 September 1917) 1917b. Chitons taken by the United States Fisheries Steamer “Albatross” in the Northwest Pacific in 1906. Proc. U.S. Nat. Mus. 54 (2223): 1-18; plts. 1-10 (5 December 1917) 1919. Preliminary notices of some new West American chitons. Lorquinia 2 (6): 4-7 (6 January 1919) 1922. Fossil chitons of western North America. Proc. Calif. Acad. Sci. (4) 11 (18): 399-526; 16 plts.; 11 figs. (16 May 1922) 1925. New or little known southern California Lepidozonas. Proc. Malacol. Soc. London 16 (5): 228-231; plt. 11 (July 1925) 1927. Notes on some British Columbia chitons. Proc. Malacol. Soc. London 17 (4): 159-164; plt. 13; 4 text figs. (May 1927) 1931. A redescription, under a new name, of a well-known California chiton. Proc. Malacol. Soc. London, 19 (5): 255 - 258; 1 plt. (15 July 1931) Brices, Joun C. 1974. Marine Zoogeography. McGraw-Hill Book Co., New York 475 pp. Burce#, Jenn Quincy « THomas Apams BurcH 1943. List of species dredged on shale bed off Del Monte, Monterey, Galifornia, 10-35 fathoms, in August 1940. Minutes Conchol. Club South. Calif, no. 2: 5-6 (J. Q. Burch, ed.) (April 1943) Burcu, THomas ADAMS 1942. Dredging off Redondo Beach, California. Minutes Conchol. Club South. Calif. no. 17: 5-11 (J. Q. Burch, ed.) (November 1942) BurcHarpT, GLENN E. & Laura E. BuRGHARDT 1969. A collector’s guide to West Coast chitons. Spec. Publ. No. 4, San Francisco Aquar. Soc., Inc., 45 pp.; 4 color plts. 7 text figs. (November 1969) Caruisiz, Jonn G., Jr. 1969. Invertebrates taken in a six-year trawl study in Santa Monica Bay. The Veliger 11 (3): 237 - 242 (1 January 1969) CarPENTER, Puitip PEARSALL 1864a. Diagnoses of new forms of mollusks collected at Cape St. Lucas by Mr. J. Xantus. Ann. Mag. Nat. Hist. (3) 13 (76): 311-315 (April) ; (78): 474-479 (June); 14 (79): 45-49 (July) [reprinted in Carpenter, 1872 (C): 207-221 (also pp. 1-13)] 1864b. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Reprt. Brit. Assoc. Adv. Sci. 33 (for 1863): 517-686 (post 1 August 1864) (reprint: 1872, Smithson. Misc. Coll. 10 (252): 1-172; origi- nal paging at top of page) 1865. Diagnoses specierum et varietatum novarum moluscorum, prope Sinum Pugetianum a Kennerlio Doctore, nuper decesso, collectorum. Proc. Acad. Nat. Sci. Philadelphia 17 (2): 54 - 64 (7 August 1865) 1866. Descriptions of new marine shells from the coast of California. Pt. III. Proc. Calif. Acad. Sci., (1) 3: 207 - 224 (February 1866) 1872. The mollusks of western North America. Embracing the second report made to the British Association on this subject, with other papers; reprinted by permission, with a general index. Smithson. Inst. Mise. Coll. 10 (252): xii+325 pp. + pp. 13-121 (December 1872) Cuace, Emery PERKINS 1917. Fossil chitons. Lorquinia 2 (4): 30 (November 1917) 1958. | The marine molluscan fauna of Guadalupe Island, Mexico. Trans. San Diego Soc. Nat. Hist. 12 (19): 319-332; 1 fig. (16 October 1958) Cracrz, Emery Perkins & Erste Marcaret Hersst CHAcE 1919. An unreported exposure of the San Pedro Pleistocene. Lor- quinia 2 (6): 1-3 (January 1919) 1930. Two seven-valved chitons from Mendocino, California. The Nautilus 44 (1): 7-8 (17 July 1930) 1933. Field notes on chitons of Crescent City, California. The Nautilus 46 (4): 123-124 (25 April 1933) Coorgr, James GRAHAM 1867. | Geographical catalogue of the Mollusca found west of the Rocky Mountains between 33° and 49° north latitude. San Francisco (State Geol. Surv. & Towne & Bacon). 40 pp. (post-April 1867) Dati, Wittiam Heatey 1879. | Report on the limpets and chitons of the Alaskan and Arctic regions, with descriptions of genera and species believed to be new. Proc, U. S. Nat. Mus. 1: 281-344; 5 plts. (15-19 February 1879) 1919, Descriptions of new species of chitons from the Pacific coast of America. Proc. U. S. Nat. Mus. 55 (2283): 499-516 (7 June’19) 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 unfigured species. U. S. Nat. Mus. Bull. 112: 1-217; plts. 1-22 (24 February 1921) FERREIRA, ANTONIO J. 1974. The genus Lepidozona in the Panamic province, with the descrip- tion of two new species (Mollusca : Polyplacophora). The Veliger 17 (2): 162 - 180; 6 plts. (1 October 1974) 1977. A new species of chiton from the Aleutian Islands (Mollusca : Polyplacophora). The Veliger 20 (1): 27-29; 1 plt.; 1 text fig. Fraser, G. McLean ; 1932. A comparison of the marine fauna of the Nanaimo region with that of the San Juan Archipelago. Trans. Roy. Soc. Canada (3) 62 (5): 49-70 (May 1932) Go.pBerc, Epwarp D. 1965. An observation on marine sedimentation rates during the Pleisto- cene. Journ. Limnol. & Ocean., Suppl. 10: 125 - 128; 1 text fig.; 1 table (November 1965) Heatu, Haroitp 1904. The larval eye of chitons. Proc. Acad. Nat. Sci. Philadelphia 56: 257 - 259, figs. A-C (4 May 1904) 1905. The breeding habits of chitons of the California coast. Zool. Anz. 29 (12): 390 - 393 (19 September 1905) Herrman, Eucene S. 1968. A ctenostomatous ectoproct epizoic on the chiton Ischnochiton mertensii. The Veliger 10 (3): 290-291; 2 text figs. (1 January 1968) Vol. 21; No. 5 Husss, Carr 1967. A discussion of the geochronology and archeology of the Cali- fornia Islands. Proc. Sympos. Biol. of the Calif. Islds. (Ralph N. Philbrick, ed.), Santa Barbara Botanic Garden, Santa Barbara, Calif., 363 pp., illust. IrEDALE, Tom « A. F Basset Huy 1922-1924. A monograph of the Australian loricates. Austral. Zool. g: 186-194; 227-238; 277-297; 339-362; 4 text figs.; plts. 33-373 39-40 Jaxovieva, A. M. 1952. Shell bearing mollusks (Loricata) of the seas of USSR. Acad, Sci. USSR, no. 45, Keys to the Fauna of USSR, 127 pp. (Jerusalem transl. 1965) JOHNSON, MYRTLE ELIZABETH & HARRY JAMES SNOOK 1927. Seashore animals of the Pacific coast. New York, xiv + 639 pp.; illus.; 11 plts. (reprinted, 1967, Dover Press, New York) Kaas, PB 1972. Polyplacophora of the Caribbean region. Studies on the fauna of Curacao and other Caribbean islands. 41 (137): 162 pp.; 247 text figs.; 9 pits., Martinus Nijhoff. The Hague (July 1972) Keep, Josiau 1887. | West coast shells. pp. 1 - 230; figs. 1- 182 (fig. 41, frontis., in color). Bancroft Brothers & Co., San Francisco (reprinted: 1888, 1891, 1893) La RocQvE, AURELE 1953. Catalogue of the Recent Mollusca of Canada. Bull. 129: p. ix +406 pp. Le.oup, Euczknz 1940. Charactéres anatomiques de certains chitons de la céte californi- enne. Mem. Mus. Roy. Hist. Nat. Belg. (2) 17: 1-415; 94 text figs. (go April 1940) The Macmillan Company, Nat. Mus. Can. Licut, So. FELTy 1941. Light’s manual. Laboratory and field text in invertebrate zoolo- gy, 18t ed.: pp. i- vii; 1-232; 136 text figs. Liogt, Sor Ferty, RatpH INcRAM SMITH, FRANK A oysius PiTe.Ka, Donatp Putnam Apsott e& Frances M. WEESNER 1954. Intertidal invertebrates of the central California coast. i- xii+ 443 pp.; 138 figs. Berkeley, Calif. (Univ. of Calif. Press) Situ, Race I. «& James T. Carton 1975. Light’s manual. Intertidal invertebrates of the central Califor- nia coast. 3m ed. pp. i- xviiit1- 716; illust. Univ. Calif. Press, Berke- ley Lowe, Hersert NELSON 1904. A dredging trip to Santa Catalina Island. 18 (2): 18-20 McLgan, James Hami_tton 1969. Marine shells of southern California. Los Angeles County Mus. Nat. Hist. Sci. Ser. 24, Zool. no. 11: 104 pp.; 54 text figs. (October 1969) The Nautilus (6 June 1904) MIDDENDORFF, ALEXANDER THEODOR VON 1847a. Vorlaufige Anzeige bisher unbekannter Mollusken, als Vorarbeit zu einer Malacozoologia Rossica. Bull. Classe Phys.-Math. Acad. Imp. Sci. St. Petersburg no. 128, 6 (8): 113-122 (20 April 1847) 1847b. Beitrage zu einer Malacozoologia Rossica, I. pp. 125 - 127, plt. XIV Nierstrass, Huco FRIEDRICH 1905. Die Chitonen der Siboga-Expedition. 48, 112 pp.t+addendum; 8 plts. Ovproyp, Ipa SHEPARD 1924. | The marine shells of Puget Sound and vicinity. Publ. Puget Sound Biol. Sta. 4: 272 pp.; 49 plts. 1927. The marine shells of the west coast of North America. Univ. Press, Stanford, Calif. 2 (3): 1-323; pits. 73-108 Ed. Note: this work is divided into 2 volumes, of which the second is divided into 3 parts; each part is separately, as well as continuously, pag- inated. The numbering system of the plates is continuous only through the 3 parts. Orcutt, Crarvtes Russe. (with comments by Witt1am Hearey Datt) 1885. Notes on the mollusks of the vicinity of San Diego, Cal., and Todos Santos Bay, Lower California. Proc. U. S. Nat. Mus. 8: 534-544 (10 Oct.); plt. 24 (21 Oct.) ; 545-552 (26 October 1885) Pacxarp, Earv L. 1918. Molluscan Fauna from San Francisco Bay. Univ. Calif. Publ. Zool. 14 (2): 199 - 452; plts. 14-60 (12 September 1918) Siboga-Expeditie, no. Univ. Wash., (March 1924) Stanford THE VELIGER Page 43 PaLMeR, KaTHERINE EvANGELINE H1LTON VAN WINKLE 1945. Molluscan types in the Carpenter collection in the Redpath Museum. The Nautilus 58 (3): 97 - 102 (19 February 1945) 1958. Type specimens of marine Mollusca described by P P Carpenter from the West Coast (San Diego to British Columbia). Geol. Soc. Amer., Mem. 76: viiit+376 pp.; 35 plts. (8 December 1958) Puituirs, Tep 1971. A range extension for Lepidozona californiensis Berry, 1931. The Tabulata 4 (3): 22 (1 July 1971) Pirssry, Henry Auacustus 1892, Polyplacophora. In Tryon: Manual of Conchology, 14: i to xxxiv+1- 128 pp., 1-30 plts. 1893a. Polyplacophora. In Tryon: Manual of Conchology, 14: 129 to 350 pp.; plts. 31 - 68 1893. Polyplacophora. 5 - 133; plts. 1-17 1896. Notes on some West American chitons. The Nautilus 10 (5): 49-51 (1 September 1896) 1898. Chitons collected by Dr. Harold Heath at Pacific Grove, near Monterey, California. Proc, Acad. Nat. Sci. Philadelphia 50: 287 - 290 (12 July 1898) Reeve, Lovett Auaustus 1847. | Conchologia iconica or Illustrations of the shells of molluscous animals. vol. 4 (August, 1847) Rice, Tom 1971. Marine shells of the Pacific Northwest. Ellison Industr. Inc. Wash. 102 pp.; 40 plts. Ricketts, Epwarp F. & Jack CaLvin 1962. Between Pacific tides. 3rd ed. Revised by Joel W. Hedgpeth. xiii+516 pp.; illus. Stanford Univ. Press, Stanford, Calif. SABELLI, BRUNO 1974. Origine e distribuzione dei Polyplacophora viventi in Mediter- In Tryon, Manual of Conchology 15: Edmonds, Washington, (June 1971) raneo. Quad. Civic. Staz. Idribiol. Milano 5: 71-78 (Sept. 74) SimrotH, Hernricu Rupo.F « H. HorrMANN 1929. Polyplacophora. in: Bronn’s Klassen und Ordnungen des Tier-Reichs 3 (Mollusca) (1): 129-368 SirEnxko, B. I. 1975. On the taxonomy of the genus Lepidozona Pilsbry. Mar. Biol. No. 3, Acad. Sci. USSR, pp. 13 - 28 (in Russian) SmitH, ALLyN Goopwin 1947. Check-list of West North American marine mollusks: Class Am- phineura, order Polyplacophora. Minutes Conch. Club South. Calif. (J. Q. Burch, ed.) 66: 17-19 (Jan.-Feb. 1947) 1960. Amphineura. In Treatise on Invertebrate Paleontology, ed. Moore, Part I, Mollusca 1, pp. 41 - 76; figs. 31-45 1963. A revised list of chitons from Guadalupe Island, Mexico (Mol- lusca : Polyplacophora). The Veliger 5 (4): 147-149 (1 April) 1977. Rectification of west coast chiton nomenclature (Mollusca : Polyplacophora) . The Veliger 19 (3): 215-258 (1 January ’77) SmitH, ALLYN Goopwin & ANTONIO J. FERREIRA 1977. Chiton fauna of the Galapagos Islands. 82-97; 4 plts. Smitu, ALLYN Goopwin & IAN McTaccart Cowan 1966. A new deep water chiton from the Northeastern Pacific. Occ. Pap. Calif. Acad. Sci. 56: 1-15; 21 figs. (30 June 1966) SmrtuH, ALLyN Goopwin & MacKenziz Gorpon, Jr. 1948. The marine mollusks and brachiopods of Monterey Bay, Califor- nia, and vicinity. Proc. Calif Acad. Sci. (4) 26 (8): 147-245; pits. 3, 4; 4 text figs. (15 December 1948) STOHLER, RUDOLF 1930. | Gewichtsverhaltnisse bei gewissen marinen Evertebraten. Zool, Anz. gt (5/8) 149-155 (October 1930) The Veliger 20 (2): (1 October 1977) TakI, Isao ; 1938. | Report of the Biological Survey of Mutsu Bay, 31. Studies on Chi- tons of Mutsu Bay with general discussion on chitons of Japan. Sci. Reports of the Tohoku Imperial University, ser. 4, Biology, 12 (3): 323 - 428. 21 plits.; 5 text figs. Sendai, Japan (January 1938) Taxi, Iwao 1964. Classification of the class Polyplacophora, with a list of Japanese chitons. Venus 22 (4): 401-414 (March 1964) TatmapceE, Ropert RAYMOND 1973. Additional notes on some Pacific coast Mollusca, geographical, ecological and chronological. The Veliger 15 (3): 232 - 234 (1 January 1973) Page 44 THE VELIGER Vol. 21; No. t THIELE, JOHANNES 1893. | Das Gebiss der Schnecken zur Begriindung einer natiirlichen Classification. 2: 351 - 401; plts. 30-32. Polyplacophora Tuompson, T. G. « T. J. Coow 1955. The strontium-calcium atom ratio in carbonate-secreting marine organisms. Pap. Mar. Biol. Oceanogr., Deep-Sea Res., suppl. to 3: 20 - 39 Tuorpe, Spencer R., Jr. 1962. A preliminary report on spawning and related phenomena in California chitons. The Veliger 4 (4): 202-210; 4 text figs. (1 April 1962) WHITEAVES, JOSEPH FREDERICK 1887. On some marine invertebrates dredged or otherwise collected by Dr. G. M. Dawson, in 1885, on the coast of British Columbia; with a supplementary list of a few land and fresh water shells, fishes, birds, etc. from the same region. Trans. Roy. Soc. Canada 4 (4): 111 - 1373 4 text figs. (4 March 1887) WILLETT, GEORGE 1919. Mollusca of Forrester Island, Alaska. Univalves (cont. from p. 69) The Nautilus 33 (1): 21-28 (16 July 1919) 1935- Some superfluous names in West American chitons. The Nautilus 49 (2): 42-44 (8 November 1935) 1941. A new Ischnochiton from Catalina Island, California. Bull. South. Calif. Acad. Sci. 39 (3): 185-186; plt. 31, figs. 1, 2 (31 March 1941) Woop, Wivuiarp M. & WiLtt1AM JAMES RayMOND 1891. Mollusks of San Francisco County. The Nautilus 5 (5): 54-58 (17 September 1891) Vol. 21; No. 1 THE VELIGER Page 45 Wharf Piling Fauna and Flora in Monterey Harbor, California EUGENE C. HADERLIE ann WINFIELD DONAT III Naval Postgraduate School, Monterey, California 93940 (1 Plate; 10 Text figures) INTRODUCTION ON THE WEST coaSsT of the United States few studies have been made on the identity and distribution of wharf piling dwellers except for investigations associated with the destructive effects on wooden piles of shipworms and gribbles. Ricketts (see first edition of RICKETTS & CALVIN, 1939) was one of the first investigators to look critically at the organisms living on piles along the Pacific coast. He observed the different populations on piles in pro- tected harbors as contrasted to those under piers on the open coast, and noted that, although there was a general intertidal zonation of plants and animals on the piles, this zonation was not as sharp and well-defined as that ob- served on the Atlantic coast. Ricketts paid particular at- tention to wharf piling dwellers in Monterey Harbor and in the late 1920s and early 1930s observed the initial colonization of the piles under a newly constructed wharf. In the intervening years a number of investigators, mainly students and staff from Hopkins Marine Station, have made observations on and have collected animals and plants from various harbor pilings. Also, since 1965, in- vestigators from the Naval Postgraduate School have con- ducted long-term fouling studies in the harbor, and in 1968, Lanc, as part of a student SCUBA project, did a photographic survey of the most common plants and ani- mals dwelling subtidally on the piles. The settlement and growth of sessile marine invertebrates on experimental piles in the harbor was investigated by HADERLIE (1974). Monterey has been a port since 1602 when it was es- tablished as the center of Spanish California. The first substantial wharf to be built on the Pacific coast was con- structed at Monterey in 1845. Following this, during the height of the California whaling industry in the 1870s and the sardine fishery following World War I, a number of wharfs using wooden pilings were built and rebuilt. The only surviving wharf of this group is the one now known as Fisherman’s Wharf which has been repaired constantly by replacing piles. It had been recognized for many years that a more substantial, permanent wharf was needed, not only to serve the fishing fleet but also to fa- cilitate the unloading of cargo, particularly lumber, from ocean-going ships. In 1926 plans were drawn for a major new wharf and construction begun. The new wharf, com- pleted in 1927, is now known as Monterey Municipal Wharf No. g. In the late 1920s Ricketts made collections from the concrete and wooden piles supporting this wharf. As of now, some of the piles have been in the water for 50 years and carry a massive aggregation of organisms. The variety and biomass of the growth on these piles equal or exceed those found on the rocky shore nearby, yet, until this present investigation, the piles had not been subjected to qualitative and quantitative biological scrutiny. In 1974 a detailed study was initiated on the piles and sea walls of Municipal Wharf No. 2. It was immediately obvious that no two piles carried the same population of organisms. Indeed, some piles carried populations quite distinct from others. Piles at the distal end of the wharf are colonized, in general, with organisms tolerant of wave shock, for the end of the wharf is exposed. Organisms on the piles at the shoreward end of the wharf are those characteristic of quiet harbor water. For this study we have looked at the intertidal growth on most of the piles and recorded the major organisms that are obvious to the naked eye. We have also made a similar survey of the sea walls associated with the wharf. Using SCUBA we have examined and recorded the major subtidal organisms from both wooden and concrete piles along the length of the wharf. In the 3 years this study has been in progress we have also had the opportunity to examine 25 wooden fender piles, some having been in place 20 years or more, which have been removed and replaced. These gross observations gave us some idea of the diversity and density of living organisms on the piles from various parts of the wharf. To gain detailed knowl- edge regarding the numbers and kinds of wharf piling dwellers we realized we would have to remove totally Page 46 the mass of organisms down to the substrate and make a detailed laboratory analysis of the collection. For this de- tailed study we selected 4 concrete piles in one row under the main wharf which seemed to be fairly representative of the wharf as a whole. We had intended to subject each of these 4 piles to detailed study from above the high water line to the sediment line at the bottom. We were able to complete the analysis for the intertidal organisms on all 4 piles. The subtidal survey proved so laborious and the laboratory work so time consuming, however, that only one of the 4 piles was completely analyzed. This paper is an attempt to summarize what we have learned. The detailed subtidal work resulted in a master’s thesis (Donat, 1975), and a preliminary report on the intertidal work has been published (HADERLIE, 1977). ACKNOWLEDGMENTS The authors wish to express appreciation to the various harbormasters of the City of Monterey over the years for permission to work under the wharf. Special thanks are extended to Mr. Peter V. Constanti, Harbor Maintenance Supervisor, for his continued help and cooperation. We are also indebted to many diving partners, especially Jack Mellor, Jim Buckingham, Richard Blumberg and Jerry Norton, for help in many diving operations, and to Dr. I. A. Abbott and Lynn Hodgson for help in surveying and identifying the marine plants. The work reported on here has been supported by the Naval Facilities Engineering Command. AREA or STUDY: Description of Monterey Municipal Wharf No. 2 Figure 1 includes a vicinity map and shows the present configuration of Monterey Harbor. Figure 4 is an aerial photograph of the harbor and adjacent area of Monterey Bay. Figure 2 presents a plan view of Monterey Munici- pal Wharf No. 2. This wharf has its footing on the sandy shore at the base of Figuroa Street in Monterey and ex- tends northward into the bay for approximately 530m. At the distal end of the wharf the water is 8 to 10m deep. The initial part of the structure is a causeway 10m wide running seaward for 341m. It is supported by wooden piles approximately 30cm in diameter. The piles are in 80 rows of 6 piles each, each row 4.27 m apart. The cause- way piles out to the position of the north sea wall (see below) are encased in concrete jackets to about 1 m above the highest tide level. Beyond the causeway for a distance THE VELIGER Vol. 21; No. 1 Francisco Monterey Bay ° , Breakwater Maa Monterey Bay Fisherman’s arf Municipal _ Wharf No. 2 sete, Figure 1 Map Showing Configuration of Monterey Harbor of 57 m the section is called the lumber wharf. It is 18m wide and supported by 14 rows of wooden piles, 10 piles per row, the rows 4.27m apart. The section beyond the lumber wharf is called the main wharf. It is 25.7 m wide, 128 m long, and is supported by 36 rows of concrete piles, the rows 3.65 m apart and containing 12 piles. The main wharf accommodates a large building that houses fish processing plants. The basic configuration of the wharf has remained the same since its construction but over the years additions and alterations have been made. To protect the wharf (on facing page —) Figure 4: Aerial photograph of Monterey Harbor (17 September 1971, official U.S. Navy photograph by VC-63 squadron NAS Miramar) Nk 2 Bo cy a < A {e) Q &B Q = a4 Q EI oh, Tue VELIGER, Vol. 21, No. 1 Vol. 21; No. 1 North Sea Wall Marina THE VELIGER Page 47 Main Wharf Row of Concrete Piles Investigated Tide Gauge Lumber Wharf Causeway East Sea Wall Figure 2 Monterey Municipal Wharf No. 2 structure from damage by large fishing boats and ships moored during periods of strong surge, a series of wooden fender piles were driven arond the entire periphery of the wharf, normally one fender pile at each end of each row of supporting piles. Because of wear these wooden fender piles are removed and replaced periodically. All wooden piles used in the wharf construction and repair have been Class A Douglas fir pressure treated with 6.3 kg creosote according to standards of the American Wood- Preserver’s Association. They vary in diameter from 25, to 35cm. Each concrete pile under the main part of the wharf is octagonal in cross-section, approximately 2m in cir- cumference (61cm diameter) and extends from the base of the wharf deck 5m above mean lower low water (MLLW) to the bottom 7-8m below MLLW. The piles were poured in forms on land, and were made of steel reinforced concrete using portland cement and a good quality granite aggregate. They were then driven in place and capped with concrete beams. Most of the concrete, both above and below the water, is in excellent condition after 50 years, however, there is evidence that many of the steel reinforcing rods have corroded away. Monterey is situated at the southern end of Monterey Bay which is broadly open to the Pacific to the west. It is not a natural harbor and is particularly exposed to waves and swell from the northwest. To give some pro- tection to the wharfs in the harbor, and to the mooring area of the large fishing fleet that became permanently home-ported at Monterey in the 1920s, an extensive per- meable breakwater consisting of granite rock was con- structed by the U.S. Army Corps of Engineers between 1931 and 1934. The position of this breakwater is shown in Figure 1 and Figure 4. The breakwater gives consid- erable wave protection to Municipal Wharf No. 2, but does not alter significantly the water circulation in the area of the wharf itself. In 1959-60 a major addition to the harbor and wharf was made. To accommodate an ever increasing number of fishing boats and pleasure craft, a marina with floating docks was constructed between Municipal Wharf No. 2 and the older Fisherman’s Wharf. Figure 4 shows the configuration of the marina. To gain the quiet water nec- essary for a marina, a sea wall was built between the two wharfs with a narrow passageway near Fisherman’s Wharf allowing boats to enter and leave the marina. This sea wall, known as the north sea wall or frontal wall, is con- structed of braced pilings with heavy wooden planks (20x 30cm in section) forming a nearly impermeable bar- rier from above high water line to the bottom. A fishing pier has been built on top of the sea wall. To protect the marina from the accumulation of sand caused by lit- Page 48 toral drift from east to west, and to give additional pro- tection from waves and surge from the open bay, a sea wall was also constructed along the east side of the cause- way of Municipal Wharf No. 2 out to the level of the north sea wall. This so-called east sea wall was constructed adjacent to the east side of the causeway of additional fender piles with heavy wooden planking (15 x 30cm) forming an impermeable barrier. Additional wooden piles were driven diagonally into the bottom to the east of the sea wall to brace the entire structure. To the west of the marina the extensive piling under Fisherman’s Wharf dampens any wave action from that direction. The only major unobstructed opening into the marina is the passageway for boats, therefore no significant wave action occurs and the currents within the marina are primarily tidal currents. As a result of the construction of the ma- rina, the fauna and flora on the now enclosed piles of the causeway have been altered significantly as will be noted below. ENVIRONMENTAL PARAMETERS For many years the Naval Postgraduate School has oper- ated a tide gauge on the wharf near the main study site of this investigation. Using the original blueprint of the wharf as drawn in 1926, the tide gauge is located near pile J, Bent 11. Its position is shown in Figure g. At this same site, daily surface temperatures are recorded and, at times, bottom water temperatures. Salinity determina- tions are also made periodically. The detailed records are maintained by the Department of Oceanography, and those of specific years have been summarized by Donat (1975), HADERLIE (1968, 1969, 1974) and HADERLIE & MELLor (1973). Only an over-all summary of these rec- ords will be given here. The maximum spring tidal fluctuation in Monterey Harbor is about 2.7 m; from 2.2 m above mean lower low water (MLLW, defined as 0.0 m tide level) to 0.5 m below MLLW. Between 1966 and 1977 the highest surface tem- perature (17.4° C) was recorded in September 1968, and the lowest (9.5° C) in March 1971. The average low tem- perature over the past 10 years has been 11—12°C and the average high, 15—16° C. In most years there is a gen- eral upward trend in surface temperature from January to September, with a sharp decline from September through December. The surface salinity of harbor water for the past several years (when averaged monthly) ranged from 32.8°/o0 to 33.8°/oo. Water under that part of the wharf seaward of the north sea wall of the marina circu- lates freely and at times strong tidal currents and surges THE VELIGER Vol. 21; No. 1 occur. The water is well aerated and relatively unpol- luted. The piles under the causeway to the east of the marina, however, are in relatively quiet water subject to minimal currents and the water in this area is somewhat polluted, especially by oil spills from boats moored in the marina. No detailed temperature and salinity records have been maintained for the marina area. The sea bot- tom under the wharf consists of fine sand and sediment with a mean grain diameter between 0.25 and 0.125 mm. Direct sunlight irradiates the piles on the eastern side of the wharf for a few hours in the morning; piles on the western side are subject to direct sunlight for longer pe- riods in the afternoon. Some direct sunlight reaches the piles near the middle of each row only in late afternoon and the general dim light conditions limit the number of plants in this area. METHODS Municipal Wharf No. 2 is supported by about 1,300 piles. Over the past 10 years most of these have been examined, some fairly casually, a few in considerable detail. Depend- ing upon the detail of examination, the methods varied. As a whole two routines were followed. In what we will call our general survey, many piles and the sea walls were grossly examined to determine the dominant kinds of organisms in each area and their relative abundance and vertical distribution on the pile or portion of the sea wall. Except to confirm the identity of species, no extensive collections of organisms were made. For a few concrete piles, however, we made a detailed survey where all or- ganisms on one face of the pile were removed, the biomass of each vertical segment determined, and a detailed spe- cies count made. Each of these two types of survey methods will be discussed in more detail. A. GENERAL SURVEY a. Intertidal Area In the intertidal zone at the shoreward end of the causeway the piles and east sea wall were examined at low tide on foot. For the remainder of the sea wall and piles out to the end of the wharf small boats and rafts were used. Surveys were made at low tide (0.0m or lower) and the piles and sea wall were examined from —o.5 m tidal level to the highest reaches of the tide. The general distribution and abundance of all macroscopic, easily identifiable plants and animals were noted. Vol. 21; No. 1 b. Subtidal Area For subtidal work SCUBA gear was used. A weighted line, marked off in 0.5 m increments was deployed along each pile being studied and a census was made using un- derwater slates. Approximately 20 representative wooden piles and 10 concrete piles were surveyed. Some photo- graphs were taken of specific sections of piles, but, in gen- eral, detailed photography was limited to the concrete pile studied in the detailed survey (see below). During 1976 and 1977 approximately 30 wooden piles were pulled and replaced by the Harbor Maintenance Super- visor, and 25, of the removed piles were examined imme- diately after they were lifted from the water with a census made and vertical distribution of organisms determined. B. DETAILED SURVEY It was recognized early in this study that a detailed analysis of the fauna and flora on the various piles under the wharf was needed. Yet our general survey indicated that there were often great differences from pile to pile. We could not possibly perform a detailed analysis on more than a few piles; thus, it was desirable to select piles that were fairly representative of those under the wharf in that each carried a somewhat different population rep- resenting the range found on all the piles. We ultimately settled on 4 concrete piles in a single row under the main part of the wharf. The specific piles selected for study are in the 25th row from the end of the wharf—one at the eastern edge of the row (designated Pile A), 2 near the middle (Piles B and C) and one near the western edge of the row (Pile D). The general position of the row is indicated in Figure 2, and Figure 3 shows a cross-section of the wharf with the specific piles labelled. On the orig- West Figure 3 Section Through Wharf at Level of Concrete Piles Investigated THE VELIGER Page 49 inal 1926 blueprint of the wharf filed in the City Engi- neer’s Office, City of Monterey, Piles A, B, C and D are designated L, J, F and B, Bent 12. a. Intertidal Area In order to gain continual access to the piles being studied a series of cat-walks were constructed along the row of piles. Ladders suspended from the cat-walks and extending to below the lowest tide level were placed ad- Jacent to each study pile. Small boats and rafts were also employed. After an initial survey of the organisms at- tached in the intertidal zone on each of the four piles was completed, and before any of the attached fouling growth was removed, a photograph was taken of each 0.5 m segment of each pile. The fouling growth around the periphery of any one pile at a specific level proved to be much the same, i.e., the north face of the pile car- ried the same organisms in about the same concentrations as the south face. It was decided, therefore, to study only one side of each of the four piles—the south side—and leave the north side undisturbed for later reference. Each pile has a circumference of 2m, therefore, a 1m swath from high to low water on the south face of each of the four piles was investigated. After the initial census and photographic recordings were made, the south face of each pile was scraped com- pletely clean of all macroscopic fouling growth. This was done in 0.5m vertical increments, thus, each increment was 1m wide and o.5m high. The organisms were re- moved from the piles using various scrapers and chisels and were caught by an elastic apron attached around the pile below the area being scraped. The collected fouling growth from each 0.5m? increment of pile surface was placed in buckets of sea water and taken immediately to the laboratory where all the removed organisms, after pouring off the water, were weighed (wet weight of all fouling growth for o.5 m? of pile). The organisms were then sorted in pans of fresh sea water, identified and counted. In most cases all organisms were identified while still alive, but for some polychaetes the specimens were preserved in alcohol for later identification. An attempt was made to identify and count all organisms visible to the unaided eye, but on some piles with entangled masses of worm tubes many small organisms were obviously missed. Attempts to count and quantify colonial organ- isms such as hydroids and encrusting bryozoans were es- pecially frustrating. A stereoscopic microscope was used to identify the smaller animals and plants. Page 50 b. Subtidal Area As noted above, our initial general survey of the wharf piles indicated that there were considerable differences from pile to pile in the populations of fouling organisms. This was especially true in the intertidal region of each pile. The subtidal region of the piles carried a somewhat more uniform population. The 4 concrete piles selected for detailed study were fairly representative of the wharf piles as a whole in the range of organisms living on them. We had intended to make a detailed study of the subtidal populations on all 4 of the selected piles, as had been done for the intertidal populations. The collection and analysis proved to be so time consuming and laborious, however, that we finally decided to make a general survey, including an extensive photographic record, of the sub- tidal region of each of the 4 piles and concentrate for the detailed study on only one, Pile A. During the spring and summer of 1974 a total of 8 dives was made on the 4 piles to make a general census and a photographic survey and to test collecting methods and equipment. During the fall of 1974 and up to July 1975 a series of 13 dives was made in the detailed study and collection of organisms from Pile A. Two to 3 divers participated in each dive. Photographic records were made using a Nikonos II underwater camera with a Nikkor wide-angle lens (1:3.5, f28) and a Subsea Products MK 150 underwater flash attachment. Kodak High Speed Ektachrome (ASA-160) was used for color slides and Kodak Tri-X (ASA-400) was used for black and white (see Donat (1975) for details on underwater photography). A complete file of photo- graphs of organisms living on the piles of the wharf is maintained by the Department of Oceanography, Naval Postgraduate School. As in the intertidal region of Pile A, the organisms from the south face of the pile from the —o.5 m tide level down to the bottom at —7.0 m were removed and collected. A swath 1 m wide was scraped in 0.5 m vertical increments as in the intertidal area. A weighted line marked off in 0.5m segments was placed next to the pile during each collective dive. The primary tools for removing the or- ganisms consisted of a steel chisel 18 cm long with an 8cm blade width and a small 1.6kg sledge hammer. Collection of material beyond reach when standing on the bottom necessitated the use of diving stages on which the diver could stand or kneel while working on the pile. These stages were secured above the water line to the adjacent cat-walk and raised or lowered to the correct position. A girdle line passed around the pile about 1m below the level of material to be collected gave adequate stability for the work. THE VELIGER Vol. 21; No. 1 A collection bag was improvised from an old plankton net 1.5m long with a 0.4m diameter opening. A line around the pile kept the lower lip of the bag against the pile face and the upper lip was held at a slight angle to the pile. A slow sweeping motion of the hand down into the bag opening carried the falling material that was scraped loose into the bag with negligible loss. Upon completion of scraping a 0.5 m? increment the bag was re- moved and taken to the surface. The collected material from each o.5 m? increment was taken directly to the lab- oratory, drained of all excess water, and weighed. The organisms were then placed in aquaria or porcelain pans with running sea water until they were all sorted and either identified while alive or preserved in alcohol for later identification. In the initial sorting of the collection the numerous plumose anemones (Metridium senile) were removed as soon as possible, for their protruding acontia fouled and killed many small organisms. OBSERVATIONS a. Fauna and Flora of Piles and East Sea Wall of Causeway Prior to 1959, when the marina was developed, the piles under the causeway were in open water and subject to the same tidal currents and surge as the piles under the outer part of the wharf. The animals and plants living on these causeway piles were similar in kinds and numbers to those found elsewhere on the wharf. Construction of the practically impermeable wooden sea wall along the eastern side of the causeway and the connecting north sea wall created a partially enclosed and protected area for the marina and drastically altered the water move- ments around the piles under the shoreward part of the causeway. As a result, the fouling growth on these piles is now impoverished. The remaining organisms are those tolerant of quiet harbor water that is often polluted, especially by oil spills. Subtidally, the enclosed piles of the causeway carry reasonably heavy growths of the tube worms Phyllochae- topterus prolifica, the plumose anemones Metridium senile, and numbers of hydroids, erect bryozoans, and stalked tunicates (Styela montereyensis). In the low inter- tidal zone, very few living giant barnacles (Balanus nu- bilus) are now found, whereas they were common before the sea wall was constructed. The entire intertidal area on each pile now carries a very limited population of smaller barnacles (Balanus glandula, Chthamalus dalli, Tetraclita squamosa rubescens) and anemones (Antho- pleura elegantissima, Corynactis californica). ae ae Vol. 21; No. 1 The intertidal area of the sea wall itself on the protected marina side is inhabited by many of the same animals ob- served on the adjacent protected piles, but, in addition, possesses patches of ascidians (Ascidia ceretodes, Botryllus spp.), small Metridium senile, and a few patches of Coryn- actis californica. Also, extensive growths of the encrust- ing bryozoans Celleporaria brunnea and Cryptosula palas- stana occur as well as the erect bryozoans Bugula neritina and Crisulipora occidentalis. In areas where the planks of the sea wall have separated slightly producing a crack through which sea water can flow, the opening is often lined with clumps of the stalked barnacle Pollicipes poly- merus and the bay mussel Mytilus edulis. To the east of the causeway the sea wall is supported by bracing wooden piles driven at an angle of 60° to the vertical. These piles and the east face of the sea wall are exposed to the open water of the bay and to full sunlight for several hours each day, and they are populated by a great variety of plants and animals. No attempt has been made to make a detailed survey of these organisms, but the dominant forms that can be seen in a casual inspection of the intertidal area of the piles and sea wall will be mentioned. Lush growths of marine algae occur on the east face of the sea wall. High up at the level of the highest tide is a green band of Enteromorpha compressa (Linnaeus) Greville, 1830, Slightly below, Ulva lobata (Kiitzing) Set- chell & Gardner, 1920, dominates the sea wall and extends downward to mid-tide level. Mixed with the Ulva is the filamentous green alga Urospora penicilliformis (Roth) Areschoug, 1886, and the red alga Porphyra lanceolata (Setchell & Hus) Smith, 1943. The mid-intertidal region of the sea wall is populated with well-separated plants consisting primarily of Macrocystis pyrifera (Linnaeus) C. Agardh, 1820, Gigartina exasperata Harvey & Bailey, 1851, and Cystoseira osmundacea (Turner) C. Agardh, 1820. The low intertidal zone is dominated by red algae including Polyneura latissima (Harvey) Kylin, i924, Pterosiphonia dendroidea (Montagne) Falkenberg, 1901, Tridaea cordata (Turner) Bory, 1826, and by larger brown algae including Dictyoneuropsis reticulata (Saunders) Smith, 1942, and Desmarestia lingulata (Lightfoot) La- mouroux, 1813. The animals inhabiting the east face of the sea wall are not as dense as on the adjacent bracing piles. High in the intertidal area Balanus glandula, Pollicipes poly- merus and small individual Mytilus edulis are common. Some small Mytilus californianus inhabit crevices. In the mid-intertidal zone Anthopleura elegantissima dominates the sea wall, with scattered A. xanthogrammica lower down. In the low intertidal zone and subtidally Met7i- dium senile is common, as is Ascidia ceretodes. The bryo- THE VELIGER Page 51 zoans Celleporaria brunnea and Bugula neritina are com- mon near the low tide line. Corynactis californica also occurs at this level in a patchy distribution. The asteroid Pisaster ochraceus is abundant in the low intertidal and subtidal area on the sea wall. The diagonal bracing piles of the sea wall carry dense, heavy populations of organisms similar to those on the piles under the main part of the wharf further seaward. The same plants found on the sea wall are represented on these piles, but, in addition, the low intertidal region supports numbers of red algae including Gigartina lep- torhynchus J. Agardh, 1885, Platythamnion villosum Kylin, 1925, Gellidium pusillum (Stackhouse) Le Jolis, 1863, Polysiphonia pacifica Hollenberg, 1942, and Cent- roceras clavatum (C. Agardh) Montagne, 1846. The animals inhabiting the bracing piles are similar to those found on the fender piles along the entire eastern side of the wharf (see below) and in the low intertidal area and subtidally Balanus nubilus forms massive collars around each pile. The collars are populated by great numbers of other organisms which will be described later in connection with the piles under the main wharf. Of all the piles associated with the wharf, these sloping piles are unique in often having dense clumps of Pollicipes polymerus high up in the intertidal zone, but on the under, somewhat protected, side of the pile. b. Fauna and Flora of Main Wharf Piles In later sections of this report we will present in detail our observations on organisms living on a few selected concrete piles under the main wharf. In this section we will merely give an overview of what a casual observer or diver would see in examining piles under the seaward half of Municipal Wharf No. . When we began making observations we suspected we could see some distinct differences between the popula- tions on wooden piles and those on the concrete piles. For example, it appeared that the anemone Metridium senile preferred a wood substrate and the anemone Coryn- actis californica preferred concrete. Also, the large masses of the tube worm Phyllochaetopterus prolifica were much more common on concrete piles than on wood. When one examines the oldest wooden piles under the wharf, how- ever, piles from which most of the surface creosote has leached out, one finds these piles carry populations similar to those on the concrete (except for masses of Phyllochae- topterus). The fouling population on some wooden piles has been altered due to the destructive effect of the gribble Limnoria quadripunctata Holthuis, 1949, where the sur- face of the wood has been weakened to the extent that Page 52 large masses of fouling growth become dislodged and fall to the bottom. On taking a small boat or raft under the wharf at a period of low tide the observer can examine a vast array of sessile invertebrates and algae attached to the piles in the intertidal zone. The cluster of organisms circling the piles gets thicker as one proceeds down each pile to the low water mark and at about the o.om tide level most piles possess a well-defined collar made up of the fouling growth. In some cases this collar extends out from the pile for 0.5 m or more. Clones of small anemones (Corynactis) give most of the piles splashes of color in the lower inter- tidal zone. As one proceeds along a row of piles from the east to the west side of the wharf the most obvious differ- ence one sees in the populations occupying the intertidal region is the dominance of small individuals of the anem- one Metridium senile throughout the middle and lower part of the zone on the eastern piles, and their nearly complete replacement on the inner piles and to the west by the anemones Anthopleura elegantissima and Cory- nactis californica. Macroscopic marine algae, common on the piles both on the east and west side of the wharf, are not found on the innermost piles. On most of the piles, the upper intertidal area is populated by the acorn bar- nacles Balanus glandula and Chthamalus dalli down to about 1.0m above MLLW. Between the +1.0 and +0.5 m level the dominant barnacle is Tetraclita squamosa ru- bescens and below this, forming the basis for the distinct collar around each pile, are clusters of the giant acorn barnacle Balanus nubilus, or masses of the tube worms Phyllochaetopterus prolifica. Large clusters of the cirrat- ulid worm Dodecaceria fewkesi are also found on or ad- jacent to the acorn barnacles. As one moves seaward among the rows of piles, the changes in the populations in the intertidal region are more subtle, and it is only on the outermost rows of piles that distinct differences are noted. On these piles, subject to more wave action, organisms extend further up and Balanus glandula may be found 2.5m or more above MLLW. In addition, the lower half of the intertidal zone is dominated by exceedingly large solitary green anem- ones (Anthopleura xanthogrammica), some individuals with crowns 25cm in diameter. The barnacles Balanus nubilus and B. tintinnabulum form the basis for the collar around these piles at the end of the wharf. Subtidally, the piles in any one row again show differ- ences as one moves from east to west, but are more uni- form in populations of organisms as one moves seaward along the wharf. As in the intertidal zone, the outer piles on the east are dominated by Metridium senile, some large and solitary, attached to the pile nearly all the way to the THE VELIGER Vol. 21; No. 1 bottom, whereas, Metridium is uncommon on the inner piles and those to the west. Each row of piles carries a somewhat different popula- tion from any other row, but by comparing the dominant organisms found on a series of piles along the eastern side of the main wharf with a similar series along the western side we can gain a fair idea of the populations on the piles of the wharf as a whole. Except for the marine plants, the innermost piles carry populations somewhere between these extremes. In Figures 5 and 6 we present combined observational data taken from the intertidal area and while diving on 14 wooden and concrete piles from both the east and west sides of the main wharf, and from the examination of 13 wooden fender piles removed from the east side of the wharf and 12 such piles removed from the west side. In Figures 5 and 6 only the vertical distributions of the dominant sessile organisms are plotted and no attempt is made to quantify the populations. The larger mobile ben- thic animals living on the piles are not listed, but on many piles these make up a significant amount of the biomass. Throughout the intertidal zone the sea star Pisaster och- raceus is abundant. High on the piles the lined shore crab Pachygrapsus crassipes Randall, 1839, the limpets Collz- sella digitalis and C. scabra, and the littorines Littorina scutulata and L. planaxis are common. In the low inter- tidal zone, and particularly subtidally, one commonly finds the asteroids Patiria miniata, Dermasterias umbri- cata, Pisaster brevispinus, P. giganteus, and Pycnopodia helianthoides (Brandt, 1835). The large holothurian Sti- chopus californicus (Stimpson, 1857) is occasionally seen subtidally on the piles as are the crabs Pugettia producta and Loxorhynchus crispatus. In the lower intertidal zone and subtidally among the sessile organisms the opistho- branchs Hermissenda crassicornis, Polycera atra, Aeolidia papillosa, Acanthodoris brunnea, Aegires albopunctatus, and Trinchesia albocrusta are sometimes common. DETAILED STUDY oF INTERTIDAL ORGANISMS LIVING on FOUR SELECTED CONCRETE PILES The above sections of this paper have discussed the gen- eral distribution of the largest and most obvious organisms living on the piles under the wharf observed as one grossly examines the piles. In the recesses between and under the larger organisms, however, lives a hoard of smaller organ- isms, mainly worms and small arthropods. The major effort of this investigation was devoted to a qualitative -—_—~ £ n a 3 ° & 5 a [a4 G gy 5 > Anthopleura xanthogrammica Phyllochaetopterus prolifica Tetraclita squamosa rubescens Bugula neritina Phoronis vancouverensis Dictyoneuropsis reticulata Anthopleura elegantissima Aplidium solidum Leucilla nuttingi Balanus tintinnabulum Mytilus edulis Balanus glandula Chthamalus dalli Metridium senile Balanus nubilus Polyneura latissima Macrocystis pyrifera Celleporaria brunnea Ascidia ceretodes Pododesmus cepio Leucandra heathi Figure 5 Vertical Distribution of Organisms on Piles on East Side of Wharf and quantitative analysis of the entire fauna on a few selected concrete piles in a single row under the main wharf (see above and Figure 3). This necessitated scraping the piles down to the substrate to remove all living organ- isms attached to or moving about on the pile or among the sessile organisms, and then weighing, identifying and counting the macroscopic organisms found on each verti- cal increment of the pile (see above, Methods). Balanus crenatus Vol. 21; No. 1 | THE VELIGER Page 53 + 2.0 8 q J +1.0 wal ’ I 0.0 a -1.0 | lay ‘ —9 PU BTS | E ) ~~ q mA | ] : | au | ge l ! 3 5 | 1 = ( 5 t a | rr 1. (S} ae) 5 hae ie 7 aoa eda i =10 | a ) | t i | a —6.0 q el a | -7.0 8 & & iS $ 8 2 8 8 S 8 RS keds = 3 8 g rs) a IR = Re) NS 8S ¢< Bz Ss s Q S&S SQ Sms 8 3 § a Sec RB 8 eos is) aS) Ss © 5 3 Sos & OS o 3 SS es Ss Sa BT Qe 2 eS sas S38 § SN RR Ses. eee ass 8 Bus § SS Ses PR eS Sa ess = 6 & SS sgsQPser YP ehs Sa 8 © S&S Sic) BUSS 2 Sk Bune SRS IS Sess Oe Ves es Ss oC Pees BP 8 a saz MW Ooo Qe Sse § SS a6 & Sees ors pene Sse cue eres Se@R SS ee Ss PRES sess s 3 ia A383 383 = 95 aie 3 AOGRACWTORAROROMRSQTATA Figure 6 Vertical Distribution of Organisms on Piles on West Side of Wharf The organisms living on the intertidal sections of each of the 4 piles were fairly easy to study and collect from a raft at low tide. We have therefore been able to make a detailed comparison of the intertidal fauna occupying these sections on Piles A, B, C and D. Figures 7-10 il- lustrate the general vertical distribution of the most ob- vious animals on each of the piles and give a rough mea- sure of their abundance. Data for these figures were Vertical Range on Pile (m) +2.0 0.0 Page 54 Tetraclita squamosa rubescens Anthopleura xanthogrammica Phylochaetopterus prolifica Anthopleura elegantissima Hippodiplosia insculpta Balanus glandula Littorina scutulata Collisella digitalis Celleporaria brunnea Aplidium solidum Metridium senile Balanus nubilus Littorina planaxis Chthamalus dalli Figure 7 Pile A Vertical Distribution of Animals in the Intertidal Area The width of the bars indicates relative density of individuals of the species at any one level collected prior to the removal and analysis of the fouling growth, so only those organisms visible and identifiable in place on the pile were included. Only Piles A and D carried any macroscopic algae in the intertidal zone. These algae were the same as those indicated in Figures 5 and 6 of the general survey and are not shown in Figures 7 and 10 but are discussed below. Table 1 lists in more detail all of the animals and plants identified after scrap- THE VELIGER Vol. 21; No. 1 ing the fouling growth from the intertidal section of each pile. Although each of the 4 concrete piles studied has many of the same species as part of the fouling growth in the intertidal region, the proportion, distribution, abun- dance and dominance of each species varies from pile to pile, and some piles totally lack animals that may be dom- inant on a pile close by. At the present time we know next to nothing about the reasons for these differences. The only physical parameter that is obviously different from pile to pile at the study site is the amount of light avail- able, there being some direct morning sunlight on Pile A, and a greater amount of afternoon sunlight on Pile D. Pile B is part-way and Pile C is mid-way along the row under the wharf and both are subject to dim light condi- tions most of the time. Yet, as will be seen, even piles with roughly the same light conditions each carry a slightly different mix of fouling organisms. Pile A, being on the exposed eastern side of the wharf, is subject to slightly more wave action than the other piles. Using the data shown in Figures 7-10 and Table 1, plus additional observations and measurements, the foul- ing communities on each of the four study piles will be discussed separately. The populations on these piles are perhaps climax communities for they represent ecologi- cal succession and replacement over a period of 50 years. During the period the piles have been in place they have not been disturbed seriously in any way. Pile A (Figure 7) Pile A is the easternmost concrete pile in the row studied; it is approximately 2m inward from the outer edge of the wharf. A wooden fender pile 1.5m to the northeast is at the wharf’s edge. When viewed at low tide Pile A is seen to carry three distinct bands of living animals, each band merging with the next. These will be discussed from top to bottom and the height measurements will be from o.om tide level (MLLW). +1.8 to +1.2m. Balanus glandula is dominant with the smaller barnacle Chthamalus dalli second in abun- dance. Scattered between the barnacles are isolated lim- pets (Collisella digitalis) and littorines (Littorina scutu- lata and L. planaxis). Balanus glandula individuals are well-separated at the extreme upper limit of the range and are large (average 2cm basal diameter). At about +1.7 m these barnacles be- come clustered and the largest are 1 cm or less. In the area of densest concentration (approximately +1.5 to +1.2m) the barnacles cover the piling surface in concentrations Vol. 21; No. 1 of 0.8—1.0/cm? depending on individual size. In general B. glandula become smaller at lower levels. Chthamalus dalli begin just below the highest Balanus glandula and extend down the pile between individuals of the larger barnacles. Again, the highest barnacles are the largest (0.5 cm diameter) and at +1.5m average 0.1/ cm’, but very small individuals in basal contact may exceed 6/cm?’. +1.2 to +0.6m. This band or zone is dominated by the aggregate anemone Anthopleura elegantissima, but about equally abundant are thatched barnacles (Tetra- clita squamosa rubescens). When seen from a distance this section of the pile seems solidly covered with anem- ones which average 5 cm in diameter at the upper end of their range, but when less crowded at the lower levels at- tain diameters of 10cm. In spaces between the anemones Tetraclita are found. The largest of these (3.5m diam- eter) are between the +1.2 and +1.0m level. Clusters of smaller Tetraclita occur at +1.0m in concentrations up to 1/cm?’. Most of the Tetraclita on this and other piles are overgrown or covered by a film of unidentified white Or gray material that masks the reddish color of the barnacles. +0.6 to -0.5m. This low tide zone is dominated by three large organisms: Balanus nubilus and Anthopleura xanthogrammica dominate the upper part of the zone, Metridium senile gradually replaces Anthopleura and dominates the lower part of the zone. In addition, this zone supports large colonies of Celleporaria brunnea, and at the very lowest part of the zone a thick collar of worm tubes (Phyllochaetopterus prolifica) begins and continues subtidally. Attached to the worm tubes are colonies of the ascidian Aplidium solidum and the bryozoan Hip- podiplosia insculpta. Balanus nubilus averages 10-15 cm in basal diameter in the zone and often pile upon one another to form clus- ters so that it is impossible to count them in situ. They thin out in the lower part of the zone but extend down subtidally as isolated individuals. Anthopleura xanthogrammica occur as large (10cm diameter) isolated individuals between the giant barna- cles, and because of individual size contribute significantly to the biomass of the zone. Metridium senile are small (3 cm diameter) throughout most of the intertidal range, and at about the 0.0 m level they are dominant, circling the pile in dense clusters with individuals in contact. Subtidally on Pile A solitary Me- tridium attain large size (>15,cm diameter, see below). In addition to the animals discussed above, Pile A is colonized in the intertidal zone on the eastern side by the THE VELIGER Page 55 green alga Ulva spp. from the +1.0 to the +0.3m level. The plant attaches either to bare patches of the concrete or to barnacles. Each plant is usually small (<5 cm long). In addition the following red algae are found on the pile in the low intertidal zone: Rhodomenia pacifica, Poly- neura latissima, and Pterosiphonia dendroidea. None of these plants contributes significantly to the total biomass. The brown alga Dictyoneuropsis reticulata, is represented by 2 large plants near the —o.5 m level. Pile B (Figure 8) This pile is 4m to the west of Pile A and is under the wharf far enough to be in dim light most of the day. In many respects it carries a fouling growth that is more typical of the concrete piles under the wharf than any of the others reported on here. Like the majority of the 360 concrete piles under the main wharf it has an extensive collar of fouling growth either partially or completely ringing the pile in the lowest intertidal zone. This collar is composed primarily of Balanus nubilus clustered and piled on top of one another forming a mass extending out 0.5m or more from the surface of the pile. Most of the barnacles forming the foundation of the collar are dead, having long since been smothered by those growing on top of them, but these long-dead shells are so securely cemented to the pile that one must remove them with hammer and chisel except where they have been weak- ened by extensive penetration by the boring sponge Cliona celata. The Balanus nubilus collar is practically covered by dense colonies of Corynactis californica. This pile also has three obvious bands of animals in the intertidal zone, although the middle zone is relatively sparsely populated. +1.75 to +0.75m. This band 1m in vertical extent is dominated by acorn barnacles; Balanus glandula and Chthamalus dalli extend from +1.75m down to +1.0m where they rapidly taper off and are replaced by Tetraclita squamosa rubescens. Balanus glandula are few and scattered at the upper extent of their range and average 1cm in diameter. At just below the 1.5m level they become very dense and average 0.7 cm in diameter and are in basal contact prac- tically covering the pile. Chthamalus dalli occupies roughly the same range as Balanus glandula but becomes abundant at the 1.7 m level where animals of 0.5. cm basal diameter occur in concen- trations of 1/cm?. Tetraclita occurs as isolated individuals at and just below the +1.25 m level, but becomes abundant only at +1.0m where the other two barnacles gradually disappear. The upper individuals are largest (3cm); those at the Page 56 THE VELIGER Vol. 21; No. 1 Table 1 Species living on four concrete piles in Monterey Harbor. Pile A Pile B PileC | PileD oneal i iiss esses HOS] =|] SO] SS]! pO} NO] G9! Gof |] GUD) DH} tO] =| =| S| SIN) || Sl ON) Slo Pile Increment 7 | 2/2) ©9312] 3 ale) aloe) oa) S)G ie Sle eS eel ee al|> |S |S |6)/6)|6 |S) 6/6 16) 6) 6) S).c))6)|6 |6)/6)/6 |e) eile)|> jelle) ci leilaneiie lela ahaa sis de Ta a sf a) se [Ly}-F} Ay + Hey FL | Brat 1S] SO) Of 1 te) 09] 9] G9) YB! GH) YD) DIM P| SO) OP Ol | Ol Ol Ol || Solo Species List J Sey sis/siaiSig Sie isi a/s 13/8 SIS LSS SISISISIS SIS EISIEEEE Chlorophyta | | i Ulva spp. 50 |A]R|R eee 0) 0 Phaeophyta a ay | Laminaria sp. 150 ! iP! 2: j ea Dictyoneurum californicum Ruprecht, 800 | P} van | 1852 | Hoty Dictyoneuropsts reticulata (Saunders) 100 | Re at ees ioe Smith, 1942 | | | Macrocystis pyrifera (Linnaeus) 120 | P/PiP | C. Agardh, 1820 hail Rhodophyta | a al Rhodymenta pacifica Kylin, 1931 30 He ae Pp P| P. | Polyneura latissima (Harvey) Kylin, 1924 20 | PU eh EP | Pterosiphonia dendroidea (Montagne) 15) | ip'p pp! P| P, P P P| P Falkenberg, 1901 Protozoa iia } } Gromia oviformis Dujardin, 1835 3 A\A A|A'A Al A'A,A Aj A} ALA] ATLA A|A FiA A Haplophragmoides columbiensis 0.5 | A|A|A'A'A A A!A\AIA| A] A/A} A) A F\F F Cushman, 1925 Folliculina sp. 3 IA|Al | A|A F/ F A Poriphera aie poi 1Chiona celata Grant, 1826 — P|/P|P)P P| P/P, P| P, P| P| P| P| P Je Stelletta clarella de Laubenfels, 1930 20 eG faite y (IR Leucosolenta eleanor Urban, 1905 100 P PR) PIP P. Py P| P! P| P/P Leucandra heathi Urban, 1905 60 R| IRIR/R' R, R|R R Leucilla nuttingi (Urban, 1902) 50 O} A| A/A; F| F| O; F: F| F{O/O} R/O} R A Coelenterata | a Obelia spp. 10 apa iyo lpe i ey e!te| [P| Tee P| = P|P Metridium senile (Linnaeus, 1764) 150 O|JA/A|A;A‘A!A| A}A: A) A} A} A] A] A] F Anthopleura elegantissima (Brandt, 1835) 100 FIA|R 1 | O| 0 Anthopleura xanthogrammica (Brandt, 150 RUE eae F/R 1835) | Corynactis californica Carlgren, 1936 22 R|A Platyhelminthes H Hoploplana californica Hyman, 1953 10 R/R/R{R'! R|R Notoplana acticola (Boone, 1929) 20 O}O R, | | O Notoplana inquieta (Heath & McGregor, 25 A|F'O|R 1912) Stylochus atentaculatus Hyman, 1953 80 R}| |! Stylochus tripartitus Hyman, 1953 15 R| O/O|R Eurylepta aurantiaca (Heath & 20 R| McGregor, 1912) | Nemertea Carinoma mutabilis Griffin, 1898 30 Tubulanus pellucidus (Coe, 1895) 15 Tubulanus sexlineatus (Griffin, 1898) 120 R Baseodiscus punnetti (Coe, 1904) 80 Cerebratulus californiensis Coe, 1905 100 Lineus pictifrons Coe, 1904 50 le Vol. 21; No. 1 THE VELIGER Page 57 Table 1 (continued ) rT TT aaa a a Pile A Pile B Pile C Pile D ol eee | +14) 44] [uP cp chabert at et uty a ety +h ep et ep eye] + 4] + NO | | Ol SJ OO] ef | ho] DO] 09] Oo) BY) | OT] Ot] HD] DI] DO] | | OO] Ol Oo] IO) OO] | OO Pile Increment —?"|0/&! o| @! 9} ao] Go] a o]a Oo} a) Oo] G| Ol lO} Ul oO] a] So} V) OlG! Solu Slulo meV|515/5/5/5/5/O/o/O/5 5/55 S/S SS /S/5/s)/S\s)o)5/6\5 [5/5 5515/5 /6 Np it! +) + TT Te TT Tee Te a a a oll sta) ste I} Hl A] || al] ae ae | % ir] | S| O] Of =] =f po] po] G9] Oo} BB! Or] OUD] D) Nye}! S| O] S|] | Ol SO) Olle] Ol ol oO Species List 3° lalolalola|] slulolalelaojialolalojalolalol alo} alla olalolallajo ajola I | 5 WISISISIS/S(Z(S SSIS SSS SSIS (SSIS SSSI Sie (sels is sisi3 Lineus vegetus Coe, 1931 40 R/R | | | R Micrura pardalis Coe, 1905 20 R pot Wee | Micrura verrilli Coe, 1901 70 O| O|R R | ! | | | Amphiporus bimaculatus Coe, 1901 60 A| F} O|}O HH i R Amphiporus imparispinosus Griffin, 1898 15 O;O}R| |R | R R| | Emplectonema gracile (Johnston, 1837) 150), O} A! O| O' O Hse Ne |] Dap Nemertopsis gracilis Coe, 1904 100//R| | ' ! | Paranemertes peregrina Coe, 1901 30 R R | Tetrastemma nigrifrons Coe, 1904 40 | R/O ho | |R j Sipuncula Phascolosoma agassizii Keferstein, 1867 120 F| F/F| A) A/O/O/O}F; |O|O}| FQ OG O;} A O] |F R}| O|A Annelida | | Eunoe barbata Moore, 1910 20 R | F Halosydna brevisetosa Kinberg, 1855 100 O} F/ A| Aj Al Al A] A} F| F] F| Al Al FJ} A : O/}O; Al | | AIALA A| A) A Halosydna tuberculiferaChamberlain, 1919 80 t O| R Lepidonotus squamatus (Linnaeus, 1767) 5 R Thormora johnstoni (Kinberg, 1855) 15 R R Peisidice aspera Johnson, 1897 15 | |F A|A F| A| F| F|O) F! F| FiO 0 F Paleonotus bellis (Johnson, 1897) 20 | R|O} R| R| R} O}O|R Anaitides groenlandica (Oersted, 1843) 50 | RIR | Anaitides madetrensts (Langerhans, 1880) 35 | |RJ/O|R R Anaitides mucosa (Oersted, 1843) 15 | R | Anaitides williamst Hartman, 1936 25 R| R/R Eteone californica Hartman, 1936 10 | R|R Eulalia aviculiseta Hartman, 1936 30 R| A} A/A| FJ/A F| A|O|O| F/ FO R O R Eulalia bilineata (Johnston, 1840) 40 O| O| F/R O; |OO|R | Eulalia viridis (Linnaeus, 1767) 60 R R Eumidia bifoliata (Moore, 1909) 20 O|A;A;A/O;R} |R R O Genetyllis castanea (Marenzeller, 1879) 15 | FIO|O eal R Notophyllum imbricatum Moore, 1906 100 R Sige californiensis Chamberlin, 1919 15 R/R| |R Amphiduros pacificus Hartman, 1961 20 F/O;/O/RIR R Ophiodromus pugeltensts (Johnson, 1901) — 30 O| A/A| F] F}O;]R/O;}R| F} | O O Amblosyllis sp. 15 O|}O| |RIR Autolytus varius Treadwell, 1914 30 R R Eusyllis assimilis Marenzeller, 1875 15 R Exogone sp. 5 R Haplosyllis spongicola (Grube, 1855) 40 F| F/A} F] |R/O R O O Odontosyllis phosphorea Moore, 1909 30 F| A!O/O|R F Odontosyllis sp. 20 F/ A| F/O F O Pionosyllis gigantea Moore, 1908 15 R Syllis elongata (Johnson, 1901) 35 A; A|}O}RJO/F} |O;R}| | O;O!O A 19 Je Syllis gracilis Grube, 1840 30 Oj O} O} A} A] O} O} OO} F| F] Rj R}| O| O| O Typosyllis aciculata Treadwell, 1945 10 F/R] |O/R R Typosyllis adamanteus (Treadwell, 1914) 10 O O Typosyllis bella Chamberlin, 1919 20 R Typosyllis fasciata Malmgren, 1867 20 O/O} |RIR}| |O O Typosyllis hyalina (Grube, 1863) 20 F) Aj Aj O|O/}O} F R|R Typosyllis pulchra Berkeley & 20 R O Berkeley, 1938 ii | Page 58 THE VELIGER Vol. 21; No. 1 Table 1 (continued ) Pile A Sie ee ee eee ro] —|—lols] sj —|— | rol ro] co Joo} wR] oH] | | a]/ro] Bl RH] Oo} olfro] =] | Sl olla] EH) Hl ol o Pile Increment ——]5|&|5| 5S] 5! S|! 0) a] S/G) SG] S|G|5] Glo] G] S| a] S]o] G|S/G/Slfo]u| ola] S wiz 5/516 | 15/510 /5/0/6 |o|6 16/515 /6 jo lolo S|SIS|S|S|SlSlS/slojols Shall selhary ly Wy I IU TP I a TW I sap se Sta Meta 1] | etait! eta ee hake 3" |s15 15 S|clelsleol o)a1S/2 el e|eisielsisig|s\ slalgisisislelsisisle ppcccs ety ae Eee ee eee eee ee es eee ies ei cae Neanthes caudata (delle Chiaje, 1828) 30 O Nereis eakint Hartman, 1936 100 F/ A} A} F/O R| Rj O} R} O} O}O R| F F F F/A Nereis latescens Chamberlin, 1919 40); O| |R) RIR | Nerets natans Hartman, 1936 15 R| |O R j Nereis grubei (Kinberg, 1866) 15 | © 'O Nereis pelagica neonigripes Hartman, 1936 30 R!R/R|R R Nereis vexillosa Grube, 1851 20 R O R R/R: Nereis zonata Malmgren, 1867 60 O|R R'! R Platynerets bicanaliculata (Baird, 1863) 70| I}A| Fj F R O O | F Pseudonerets, sp. 2() R R | Palola paloloides (Moore, 1909) 200]) | R/O} R| R/R | | Dorvillea moniloceras (Moore, 1909) 60 F|A| A] A| F| O} F| F| F] Oj F|O|O]O] F FIA FI FF FIA Dorvillea rudolphti Hartman, 1938 25 O|R|R Lumbriners erecta (Moore, 1904) 220 F} A} A| F| F| F/O} F/A/ F| F'O,O/R F Lumbrinens letraura (Schmarda, 1861) 100 R|R R R/R/R|/O;R; |R O R Lumbrineris zonata (Johnson, 1911) 30 O R R Limbrineris bicirrata Treadwell, 1929 50 O Arabella tricolor (Montagu, 1804) 300 A| Al F O} R/O; O;O R 0 A Arabella semimaculata (Moore, 1911) 100 O/|OJA R O/ F/R O| |A Drilonerets nuda Moore, 1909 150 R O| R|R|R | | Nainens dendritica (Kinberg, 1867) 100 R|R O} | Polydora spongicola Berkeley & 20 R Berkeley, 1950 | Phyllochaetopterus prolifica Potts, 1914 100 R/A| A} A|A} A] A] A|A}A] A; AJA|ATA P O}A Caulleriella alata (Southern, 1914) 15 F} A] A} A] A} AJA! A] A!O;} A/O| AJO Cirratulus cirratus (Miller, 1776) 20 O|R R/ |R| | Cirriformia luxuriosa (Moore, 1904) 20 O;O} |R| F/O 'Dodecacera fewkesi Berkeley & 40 AJA|A|AJ;A| A) A]A]A]A!A]A/|A;AIA O|A O Berkeley, 1954 Onoscolex pacificus (Moore, 1909) 25 FIA;A Polyophthalmus pictus (Dujardin, 1839) 12 R Capitella capitata (Fabricius, 1780) 10 R ; Sabillaria gracilis Hartman, 1944 8 R R Sabellaria nanella Chamberlin, 1919 12 R/R Amphitrite cirrata (Miller, 1776) 30 O|R| R/R O Eupolymnia crescentis Chamberlin, 1919 50 FE Neoamphitrite robusta (Johnson, 1901) 60 O O Pista alata Moore, 1909 25 F/A}R Pista brevibranchiata Moore, 1923 20 R Pista pacifica Berkeley & Berkeley, 1942 30 O Polyctrrus spp. 20 A F/O/O|R O Ramex californiensis Hartman, 1944 15 R Spinosphaera oculata Hartman, 1944 30 A O Eudistyha vancouveri (Kinberg, 1867) 140 R Thelepus crispus Johnson, 1901 40 O Thelepus hamatus Moore, 1905 25 Thelepus setosus (Quatrefrages, 1865) 10 Chone mollis (Bush, 1904) 12 Chitinopoma groenlandica (Mérch, 1863) 8 Eupomatus gracilis Bush, 1904 Vol. 21; No. 1 THE VELIGER Page 59 Table 1 (continued) Pile A | Pilec | Pitep +/+) 4/4} ftp tp yey eet ap apap ay ety ay t el] tay ate] 4] ) ye] et 4ts wl—|—lolslo]—|—|r}rmlolo/alealalalalal/r|—|—lololfre|—|—Joloffro}—|Hlolo Pile Increment |] o|U|Of@]o]alolulo DIA Olalolajo|afolalolaojiola Tolola alo rel 15/515 16/6 [6 [6 Jo JO |S | 15 16 J6 [6 [5/5 5/5 15 15 5115 [5 Jo |S Jala Jo |6 [6 Jo AS llsril arise JU) I eT Ta a alae sel a ae pse I+] + | SF fHl=lolelol=l=iy|p|elsla[slelalololal=|—|ololof-|=|ololol/—|-lolojo Species List} S SEES SSS SSESE SES SSISS ESSE E BSR REELS Serpula vermicularis Linnaeus, 1767 100 O} O| F| O} F| O} F| R} O|] O/ R/O} R R R R Spirorbis borealis Daudin, 1800 5 A| A|A|A|AI|AIALA A|A|A!|AlLA O F O Spirorbis eximius Bush, 1904 5 A] AJA; AJALAL ALA A|A/A| A) A O 13 Spirorbis moerchi Levinsen, 1883 5 Aj A] AJ AJA} A) Ay A} Ay A} AJA) ALA O Spirorbis spirillum (Linnaeus, 1758) 5 O| A| AJ A|A/A| A] AIA A|AIA|A) A O} O| F A Spirorbis spp. 5 A| A| AJA] A/A/ A] A} Aj A] A] A} A] A) A O O Arthropoda Balanus glandula, Darwin 1854 20) A] A] O F/A|R A|A|O R Balanus aquila Pilsbry, 1907 50 R Balanus crenatus Bruguiére, 1897 10 A| A] A] A] F A|A|A|A) A F O|O Balanus nubilus Darwin, 1854 150 A| F] R}R/O|R F/R}|O/O|O R\A R/O Balanus tintinnabulum Pilsbry, 1916 40 R|RIR R R R|R|O R R|R|JO Chthamalus dalli Pilsbry, 1916 5|| F| F}O A|A|O A|A|O O Tetrachita squamosa rubescens 50], | A;A F/A|F A A|A|R Darwin, 1854 Pollicipes polymeris Sowerby, 1833 40 R R Idotea resecata Stimpson, 1857 20 R/O} R|R 4 Jaeropsis dubia dubia Menzies, 1951 10 Aj A| O| F Accedomoera vagar Barnard, 1969 7 R Alylus levidensus Barnard, 1956 10 R Corophium insidiosum Crawford, 1937 5 A|A|A\A O\A|F/FI/A Micropotopus sp. 10 R Perotripus brevis (LaFollette, 1915) 5}. A| A|A/A/A A\A|A/FIA F A Deutella californica Mayer, 1890 5 A| AJA R A O Tritella laevis Mayer, 1903 5 A| A| A} AJA A|A|A|F| F Al A Caprella verrucosa Boeck, 1871 10 R Heptacarpus paludicola Holmes, 1900 30 F/O Heptacarpus taylori (Stimpson, 1857) 20 R|R R Spirontocaris prionota (Stimpson, 1854) 30 R ! Alpheus dentipes Guérin, 1832 20 R R Bateus harfordi (Kingsley, 1878) 50 R oO Loxorhynchus crispatus Stimpson, 1857 —- 150 O R R Mimutlus foliatus Stimpson, 1860 20 R A Pugettia producta (Randall, 1839) 40 R R R R R Cancer antennarius Stimpson, 1856 70 R/O| A| F/R R/R R R R| |R Cancer jordani Rathbun, 1900 30 R Cancer sp. 20 F\/A F Lophopanepeus bellus (Stimpson, 1860) 25 R| F/ F}O R|R R O Pinnixa longipes (Lockington, 1877) 12 R Pachycheles pubescens Holmes, 1900 20 O R;} |R Pachycheles rudis Stimpson, 1859 20 RIA R Paraxanthias taylor (Stimpson, 1860) 10 Petrolisthes cinctipes (Randall, 1839) 15 R Phoxichilidium femoratum (Rathke, 1799) 10 R Pycnogonum stearnsi Ives, 1892 10 F} |A;/AJAJA|R R| |R|R|R Mollusca Callistochiton crassicostatus Pilsbry, 1893 30 R Lepidozona californiensis Berry, 1931 20 R| A| F R Lepidozona mertensii (Middendorff, 1846) 20 R R Mopakia ciliata (Sowerby, 1840) 40 R} |R Page 60 THE VELIGER Vol. 21; No. 1 Table 1 (continued ) aa HU LP Ay ty ey by et ey ey +P AP ey Py tf 4} 4] 4 ro} —| =| oO] Oo] O] = DO] S99] S99] BY] BY] Ot) Or) 1D |] DO] Fe] | SO] Sl] | | OS] Olio] | | Ol oS Pile Increment "0 |G) oO} GS] alo Ola Olalolalolao} a] o} a] So} Go] G] Slo} alo] alo neo |6|6/6]o/0/0 SIS|SISISISIS IS lS HSlolSlolsslslolslolicioisjs js See ores oer esas eesleiaies a 2| 2/4 Spades us SSS S/S SSS SSS ITIS SIS FS TSS SSSI SISISISS SSIS Mopalia muscosa (Gould, 1846) 30 R Mopalia hindsii (Reeve, 1847) 80 R R Diodora aspera (Rathke, 1833) 15 R R Megatebennis bimaculatus (Dall, 1871) 12 R Acmaea mitra Rathke, 1833 8 R R Collisella digitalis (Rathke, 1833) 1I5||F | F F/O|R F/O F\O Collisella scabra (Gould, 1846) 20 Lacuna unifasciata Carpenter, 1857 5 R Littorina scutulata Gould. 1849 4k 10 O;O O O;O Littorina planaxts Philippi, 1847 51IR Alvinta compacta (Carpenter, 1864) 2 R Barleeia acuta (Carpenter, 1864) 3 R Barleeia californica Bartsch, 1920 2 R R Truncatella californica Pfeiffer, 1857 4 R Caecum californicum Dall, 1885 2 A|A|R Caecum dalli Bartsch, 1920 2 O|R Fartulum occidentale Bartsch, 1920 2 A|A Buttium atlenuatum Carpenter, 1864 6 R|R R Crepipatella lingulata (Gould, 1846) 12 R Polinices sp. ] R| |R R| |R Amphissa versicolor Dall, 1871 8 A} A|O R|R/R R/IR O F O Mttrella aurantiaca (Dall, 1871) 7 O| A/A|AJO/R|RIJO/R R R F/O Mitrella carinata (Hinds, 1844) 10 F/A/A/O/R| |R/O; |R} |RIR O O|O Mitrella tuberosa (Carpenter, 1864) 6 R|R Nassarius sp. 8 O O| |O O Fusinus luteopictus (Dall, 1877) 8 R|R R Turbonilla kelseyi Dall & Bartsch, 1909 4 R Acanthodons brunnea MacFarland, 1905 15 R Acanthodorts rhodoceras Cockerell 10 R f & Eliot, 1905 | Aegires albopunctatus MacFarland, 1905 10 R/O; |R Aeolidia papillosa (Linnaeus, 1761) 30 R| |O;/O;/O)}R R} |R| |RIR O Oo Antsodoris nobilis (MacFarland, 1905) 25 R/ RIR Archidorts montereyensis (Cooper, 1862) 15 R R/R | Cadlina luteomarginata MacFarland, 1966 12 R R Cadlina modesta MacFarland, 1966 10 R R Cadlina flavomaculata MacFarland, 1905 10 | R Carambe pacifica MacFarland & 5 R| O’Donaghue, 1929 Doriopsilla albopunctata (Cooper, 1863) 20 R R Hermissenda crassicornis (Eschscholtz, 15 O| OO} FJO/R|R}/R} |R/R R|R R O O 1831) Polycera atra MacFarland, 1905 10 R Trinchesia albocrusta (MacFarland, 1966) 10 R| A| F R R Triopha carpenter (Sterns, 1873) 5 R Triopha maculata MacFarland, 1905 5 R|R Lima hemphilli Hertlein & Strong, 1946 25 /O|R Hinnites giganteus (Gray, 1825) 30 F' A/A|F/ F/O O|}R Pododesmus cepio (Gray, 1850) 120 R| |R R|R R/O} |R/R/R/R/R F oO Adula diegensis (Dall, 1911) 5 F/O R R Vol. 21; No. 1 THE VELIGER Page 61 Table 1 (continued ) Pile A Pile B Pile C | Pile D ae oi Sea eeeaee seer ; SE FSIS SE SISINEiSistalSiieicitizlsleieitizeeieiteisigic Pile Increment 77] S|&|5| &] 5] &| So} &] S] |] O} GS} GO] &| O| GI] oO} @| oO] @| SHO] Go) G| Sllolu] ol alo wg||5|0 10/0)5/0/5/0}0/5/5)5)5/5)0 (5/5/5515 /5/5/5)5/5/5/6 Jo Io |5|5/5\6 Rey t+] + ee Se Se stg ett coe {iN Weta eta estes 1A] +) + | MH P= [SPS] S] =] =] POP NS] 9] C9] BY BY St] OY DD) NY =| SO] SO] Of =| | S] SI OI] =| S] Oo) Oo Species List (Sis 3/5/55) 51313] 3/5 15151515 S131 SIS] SISIS ISIS SISISISS SIS ISI3 Adula californiensts (Philippi, 1847) 5 R 'Lithophaga plumula kelseyt 22 R R R R | Hertlein & Strong, 1946 | Modiolus carpenteri Soot-Ryen, 1963 10 O|R|R Modiolus rectus (Conrad, 1837) 10 F/O|R | las! Modiolus capax (Conrad, 1837) 10 | |F | F Modiolus spp. 5 A|A|A|O|R R Mytilus edulis Linnaeus, 1758 30 R|RJOJAJA|A|F} |R R A|F IR R|R|R R/R Gregariella chenut (Récluz, 1842) 12 R Chama pellucida Broderip, 1835 15 R/iR| |{R Lasaea spp. 2 A|A/A|A|A/F|F]F/A/O}O Kellta laperousit (Deshayes, 1839) 15 A|A/AJA|A| F/| F|R/R/O| F/O|R/ F/R R R! R Protothaca staminea (Conrad, 1837) 8 R/R R R|R | Petricola tellimyalis (Carpenter, 1864) 5 A|JAJA|A/A|A/O]F O|O A Semele rupicola Dall, 1915 10 AIR R Cryptomya californica (Conrad, 1837) 10 R R Hiatella arctica (Linnaeus, 1767) 10 F} |AJAJA/A|A;A|A/A/A|A|A/A}A|O A|RIA O|O;|O O} 0} O 1Penitella conradi Valenciennes, 1846 10 R R Entodesma saxicola (Baird, 1863) 15 A/O|R F F 19 Lyonsta californica Conrad, 1837 15 R|R R Ectoprocta (Bryozoa) Bowerbankia gracilis O'Donoghue, 1926 = P|P/P|P|P/P/P|P P/P/P|P P|P|P P|P|P P| P|P Crista maxima Robertson, 1910 15 P|P P| |P P| Crisulipora occidentalis Robertson, 1910 ‘10 P| |P|P/P|P | P P P|P Tubulipora tuba (Gabb & Harn, 1862) 15 P/P/P|P/P P|P|P Bugula neritina Linnaeus, 1758 25 P|P|P|P|P|P|/P|P|P/P|P|P/P) P| P P|P|P P|P P| P!|P Lyrula hippocrepts (Hincks, 1882) 15 P/P/P IB P/P|P|P Membranipora membranacea Linnaeus, 30 P|P|P|P 1767 | Scrupocellaria californica Trask, 1857 40 P|/P|P|P|/P|P|P|P|P|P/P|/P|P|P|P P P P Celleporara brunnea (Hincks, 1884) 60 P|P|/P/P/P/P|P|P|P|P|P|P)P|P|P)P P|P|P P|P|P P| P|P Cryptosula pallasiana (Moll, 1803) 40 P|P|P|P|P|P|P) |P|P/P|P. P| P P|P|P P|P|P P| P|P Hippodiplosia insculpta (Hincks, 1882) 70 P|P|P| |P P P Hippothoa hyalina (Linnaeus, 1758) 30 P|P P P P Microporella californica (Busk, 1856) 20 P Phoronida Phoronts vancouverensis Pixell, 1912 — Echinodermata Strongylocentrotus purpuratus 50 R A (Stimpson, 1857) Strongylocentrotus sp. 15 A Dermasterias imbricata (Grube, 1847) 300 Patiria miniata (Brandt, 1835) 170 Pisaster brevispinus (Stimpson, 1857) 350 Pisaster giganteus (Stimpson, 1857) 200 Pisaster ochraceus (Brandt, 1835) 200 O/O R| |R R/R Amphipholis squamata (delle Chiaje, 40 1829) Ophiopteris papillosa (Lyman, 1875) 15 Ophiothrix spiculata LeConte, 1851 50 L| I as ee Page 62 THE VELIGER Vol. 21; No, 1 Table 1 (continued) +/+] 4) +) | nj} Pile Increment ———P||5| 5) 5 eS S\slaie RKeVle|5/F10/5/5)5)0 Na+] +] + yh A S| SIS Sl =] =| Species List} a WSS SiSisisisis Eupentacta quinquesemita (Selenka, 1867) 10 O|R Cucumeria miniata Brandt, 1835 50 | Chordata (Urochordata) Aplidium solidum (Ritter & Forsyth, 1917) 170 P|P|P/F/A/O Ascidia ceretodes (Huntsman, 1912) 30 O|O|R|O Pyura haustor (Stimpson, 1864) 15 Styela montereyensts (Dall, 1872) 40 O Styela truncata Ritter, 1901 10 R|R|R Wet Weight of Fouling Growth lo sl alals (Biomass) Removed from Pile (kg) l= ZI i] Explanation of Table 1 1 These species are found burrowing into the wall plates of Balanus nubilus or the upper valves of Pododesmus cepio, or both. Letters in columns refer to relative abundance of individuals of each species at the particular tidal level on 0.5m? of pile surface: Rare, 1-5/0.5m? Occasional, 6 - 10/0.5m® Frequent, 10 - 20/0.5 m? Abundant, 20+ /0.5 m? Present but numbers undetermined (used primarily for colonial animals) wu >On +1.0m level are 2—3cm in diameter and often are piled on top of one another giving a density of up to 10 large barnacles in every 100cm? surface area. +0.75 to 0.0m. This middle band on the pile is pop- ulated above by scattered Anthopleura elegantissima av- eraging 5 cm in diameter and below by Anthopleura xan- thogrammica. A few barnacles (Tetraclita) extend down to about the +0.25m level. Encrusting bryozoans (Cel- leporaria brunnea) occur between the anemones and bar- nacles along with extensive growths of the fuzzy bryozoan Bowerbankia gracilis. 0.0 to-0.5m. This extensive band in the lower part of the intertidal zone is populated by a dense aggregation of animals. Anthopleura xanthogrammica average 10cm Pile Pilec | PileD i a aT a + +1 +) +/+) _} 4) +i 4] 4! i |B] oy oD S/S SN = =|Slo wi = =|o oS S| | S|] S|& ae Sle SlolalolasS asa s ONS SjSlolojo S/S/S/S1S/S/S/5;6 Ss 15)/6 i] | i} | 1} | Sa epee eet fine se Sy KS} 52) BLS ay DD SS SSZSSissesscs Si) CK) o|o oy S] SW ot Sj ou S i> i) 3|5 3/5 |3/5/5 3/5/3//3|5 3/5 |2|3,3\3\2 2 oO hel A R PPE O | | F/ F/F/FR|F/F|R F|F | Pi ee ee R|/R/O/O|R| F/O| Ojo F All | R|O 1 | R of} | | | lo} | F R RU RR S|} a1] 09 ERE SI] a} S| or N)oO) > a) os) by} or me) oO;nN in diameter and are scattered in the upper part of this zone, but the majority of the fouling mass is composed of Balanus nubilus covered with Corynactis californica. The barnacles are as much as 15cm in basal diameter and in one area are piled up in layers 8—10 deep, the mass ex- tending out from the pile as a ledge 50cm and more in width. The outer periphery of the barnacle clusters are often completely covered with clones of Corynactis cali- fornica, each clone being of somewhat different color rang- ing from purple to orange to brilliant crimson. These vivid bands of color can be seen in this zone on most of the concrete piles under the wharf. The anemones aver- age 2cm in diameter and are in basal contact. The bar- nacle shells make up most of the biomass of this zone. When a large cluster of Balanus nubilus is removed from the pile, the innermost dead shells clearly show that these old barnacles, when alive, grew over and smothered many Tetraclita squamosa rubescens. Thus, on a newly placed concrete pile, Tetraclita apparently settle far down the pile to below the 0.0 m tide level, but are later overgrown by Balanus nubilus. The collar becomes somewhat less extensive below the -o.25m level and is gradually re- placed by a heavy growth of tube worms (Phyllochaeto- pterus prolifica) with attached slabs of the colonial ascid- ian Aplidium solidum and numerous colonies of the bryozoan Hippodiplosia insculpta. As can be seen from Table 1, numerous other smaller animals inhabit the spaces between barnacles in the col- lar. The biomass of this section of Pile B exceeds that found on any other pile studied. Vol. 21; No. 1 | THE VELIGER Page 63 +2.0 + fo) Vertical Range on Pile (m) Au, ° on 0.0 Tetraclita squamosa rubescens Celleporaria brunnea Collisella digitalis Anthopleura elegantissima Balanus glandula Littorina scutulata Chthamalus dalli Bowerbankia gracilis 8 3 S S 3 i 80 iS) 2 = S 3 R 8 had 3 XS ¥& Qa is) 2 ~ S NX Corynactis californica Phyllochaetopterus prolifica Hippodiplosia insculpta Aplidium solidum Balanus nubilus Bugula neritina Figure 8 Pile B- Vertical Distribution of Animals in the Intertidal Area The width of the bars indicates relative density of individuals of the species at any one level Pile C (Figure 9) Pile C is about midway under the wharf (8m to the west of Pile B) and has dimmer light conditions than any of the piles being considered here. When seen at low tide Pile C is encircled by 4 rather distinct bands of fouling animals. +1.75 to +1.0m. Balanus glandula dominates this band. The large solitary individuals first occur at +1.75 and average 2.0cm in diameter. Between +1.5 and +1.25 m the barnacles average 1cm in diameter and are in basal contact over most of the surface. Between and on these barnacles, the smaller Chthamalus dalli are found in sizes from 0.4 to 0.5cm and in concentrations up to 4/cm’. as 3 se 2 rat S 6 Oo fa Sg ss} fa oS [S) ‘p 5 > THE VELIGER Vol. 21; No. 1 +1.0 +0.5 I co 3 & os ) Ss iS 5 8 = St £ {= i) SS 8 &} 2 iS 8 Spe OSU -cmines aS) Sad Sona Sine 4 ~ OS Ss Ss Sy ay SS s § 3 3 Ss S&S S o = Ree oS as CS) IOS resi 5 case VO aS) 2 Ss SS US USS SHS SO NN Sie Mi, Ue ASI ene Si eo E OME ROME Tics 8 3 aw) 5 y S ne 5 i 3 6S 4 & TS 3 iS = 3 iS) SS) ok S O00 8 8 8 oS 8 8 Ss i > 'S S — S = & => o S 3 Ri Ss ES Qa so 5s Qioy 3 Sas eS) 8 & S 9 Q s iS) = = & 3 3 & = 13 iS} 2 o 2 <2 3 3 mS ots os BSS) EN RS ES ES ny ise | RN CS ES GS" 90a Sk 3 3S & v S) S a 3 SS) a CO © Bos OS SB owe Ss So ss Figure 9 Pile C Vertical Distribution of Animals in the Intertidal Area The width of the bars indicates relative density of individuals of the species at any one level +1.0 to +0.5m. This band is made up primarily of Tetraclita squamosa rubescens and Anthopleura elegantis- sima. The barnacles are up to 5.0cm in diameter and in some areas are in basal contact with each other. The anem- ones scattered between the barnacles average 5 cm in di- ameter. This band also has an extensive population of the bryozoans Celleporaria brunnea and Bowerbankia gracilis. +0.5 to 0.0m. Anthopleura elegantissima dominates this band and individuals up to 10cm in diameter are often in basal contact. Scattered among these anemones are a few individual A. xanthogrammica up to 15cm across. In the lowest part of this zone solitary Balanus nubilus are found between the anemones. 0.0 to -0.5m. This zone is dominated by Balanus nubilus, up to 14cm in diameter and often in basal con- tact but not piled up to form a collar. The barnacles are covered with Corynactis californica that also spread to cover extensive patches on the concrete piles where the barnacle does not occur. This is the only pile in the series studied that has an extensive population of Corynactis directly on the concrete pile surface. Also found in the zone are a few Anthopleura elegantissima and a greater number of A. xanthogrammica up to 12cm in diameter. Scattered through the zone are the bryozoans Bugula ner- itina and Bowerbankia gracilis and the ascidian Aplidium solidum and Ascidia ceretodes. Pile D (Figure 10) Pile D is the second concrete pile inward from the west- ern end of the row investigated. It is subject to consider- able direct sunlight in the late afternoon. The terminal concrete pile just to the west of Pile D is even more ex- posed to light and has several species of marine algae in- cluding Macrocystis pyrifera attached to it. Apart from a few small red algae the only visible plants growing in the intertidal zone of Pile D are a few specimens of the brown alga Dictyoneuropsis reticulata. The animal population making up the fouling growth shows quite different distribution and dominance com- pared to that on the other piles studied, and the animals living on Pile D are fairly typical of those on other con- crete piles in other rows along the west side of the wharf. Three major bands of fouling growth can be distin- guished. +1.7to+1.0m. Incontrast to other piles, this band on Pile D is dominated by Chthamalus dalli. The largest of these barnacles average 0.5.cm in diameter, but at high densities (4—5/cm? at +1.0m) they are somewhat smaller. Scattered through the Chthamalus dalli population are a few Balanus glandula averaging 1cm in basal diameter but these are never very abundant. A few limpets (Coll- sella digitalis) and littorines (Littorina scutulata) are also found throughout the upper part of this zone and ex- tending above it to approximately the +1.8m level. Vol. 21; No. 1 THE VELIGER Page 65 Vertical Range on Pile (m) 6 is S) S 4 S ey 3 BR 8 5 is} iS 8 3 ina 5 8 ~ ao S 8 i a) & Balanus glandula Littorina scutulata Anthopleura elegantissima Collisella digitalis Chthamalus dalli Collisella scabra Bowerbankia gracilis Aplidium solidum Balanus tintinnabulum Anthopleura xanthogrammica Balanus nubilus Corynactis californica Phylochaetopterus prolifica Hippodiplosia insculpta Strongylocentrotus purpuratus Figure 10 Pile D Vertical Distribution of Animals in the Intertidal Area The width of the bars indicates relative density of individuals of the species at any one level +1.0 to 0.0m. ‘This second band on Pile D is domi- nated by Tetraclita squamosa rubescens. These barnacles are up to 3cm in diameter at the upper part of their range where they are scattered and isolated. Throughout the middle part of their range they average 2.0cm in di- ameter and have an average density of 0.2/cm’; in re- stricted areas at the +0.5,m level, however, they are clus- tered with all of their bases in contact. The only other animal contributing significantly to the biomass in this band is Anthopleura elegantissima. Fifteen small speci- mens averaging 4cm in diameter are found in the zone. Bowerbankia gracilis is found growing over most of the barnacles and on the bare patches of concrete. 0.0 to-0.5m. ‘This lowest intertidal band on Pile D is dominated by a massive growth of Phyllochaetopterus prolifica, the densely clustered and twisted tubes of which Page 66 extend outward from the pile for 20cm or more. Em- bedded in this tube mass large solitary Balanus nubilus are found attached to the pile, each carrying a cluster of Corynactis californica. Growing directly on the Phyllo- chaetopterus tubes are massive colonies of the bryozoans Hippodiplosia insculpta and Celleporaria brunnea and the ascidian Aplidium solidum. In spaces between the tubes dozens of purple sea urchins (Strongylocentrotus purpuratus) up to 5cm in diameter are found, and down deep among the worm tubes is a vast assortment of sponges, nemerteans, sipunculids, annelids, mollusks, and small arthropods. It proved impossible to collect and iden- tify all of these, but Table 1 lists the largest and most abundant species. DETAILED STUDY or SUBTIDAL ORGANISMS LIVING on ONE SELECTED CONCRETE PILE Table 1 presents the list of organisms living on the sub- tidal portion of the south face of Pile A and includes 235, species of animals and 7 species of plants. As shown by the histogram in Figure 11 there is a definite trend of increas- ing numbers of species present at the shallower depths. The largest number occurs between —o.5 and -1.5m in association with the tubed annelid Phyllochaetopterus prolifica, the colonies of which along with the barnacle Balanus nubilus form a thick collar on the pile between the low intertidal zone and -1.5 m. At its thickest point, this collar extends out 0.4m from the pile surface. There is relatively little change in the numbers of spe- cies between —2.5 mand -6.0m. It is in this intermediate range where extensive colonies of Phoronis vancouveren- sts cover a large area of the pile surface. The dense, inter- twined tubes of these filter feeders allow very little cir- culetion of water down into their colonies. When scraped frons the pile, clouds of black, sulfur-reduced organic ma- terial were released into the water from underneath the colonies. The small annelid Caulleriella alata is partic- ularly abundant among the Phoronis tubes. Over the deepest half-meter of Pile A bare areas of the concrete surface are exposed. This is believed to be due primarily to the scouring of the pile by the fine-grain bottom sands which are moved by tidal currents. The mi- nute, calcareous tubes of Spirorbis spp. and the barnacle Balanus crenatus however, are numerous on these areas. Near the bottom, Metridium senile, so prevalent at all other depths, is relatively scarce. On the last dive following collection of organisms from Pile A a general comparison was attempted between this THE VELIGER Vol. 21; No. 1 pile and the others in the same transverse row, primarily Piles B, C and D. The most obvious difference between the populations of subtidal organisms on the four piles is that very few Metridium senile are seen on any pile in the row studied other than Pile A. When present on the other piles Metridium occur as isolated individuals and are usually much larger, some attaining a crown diameter of 10cm. The presence of Corynactis californica almost reciprocates that of Metridium in that none are found on Pile A but they are extremely plentiful on the other piles. While plentiful, their distribution is patchy. This is probably due to the clonal nature of Corynactis. Various shades of red, purple and orange delineate different clones that live in close proximity. The abundance of Corynactis is inversely proportional to depth, maximum numbers are found in the low intertidal zone. Anthopleura xantho- grammica is also seen occasionally in shallow subtidal depths on most of the piles in the row. Phyllochaetopterus prolifica is much more prevalent at all depths below the collar on Piles B, C, and D than on Pile A. This is particularly true on Pile D where large tube masses are obvious from the low intertidal zone to the bottom. Among these tubes, several large and con- spicuous animals are fairly common, including the feather duster worm Eudistylia sp. and the holothurians Eupen- tacta quinquesemita and Cucumaria miniata (Brandt, 1835). These sea cucumbers are usually completely con- cealed by the Phyllochaetopterus tubes except for their exposed oral tentacles. Another larger holothurian, Stich- opus californicus, crawls about fully exposed among the worm tubes and the barnacles. There is little difference in the subtidal Balanus nubilus populations on the 4 piles. The tunicates are not as well represented on Piles B, C and D by Aplidium solidum as on Pile A either in numbers of colonies or colony size; however, Ascidia ceratodes and Styela montereyensis are more abundant. From data contained in Table 1 we have prepared a histogram that compares the number of species found at various depths on Pile A (Figure 11). This histogram also records the total biomass for each 0.5 m? increment. It is clear from this figure that the greatest number of species is found on the pile just at, and immediately below, the lowest tide level (171 species). Most of these organisms are small and are associated with the colonies of Phyllo- chaetopterus on this pile. The greatest biomass, on the other hand, is found between the +1.0m and o.om tide level. This is the zone populated with the large anemones and the heavy barnacles (Anthopleura xanthogrammica and Balanus nubilus). Number of Species per 0.5 m? Vol. 21; No. 1 THE VELIGER Page 67 175 | = Number of Species = Wet Biomass 150 22.0 125 20.0 18.0 100 16.0 14.0 75 12.0 10.0 50 8.0 Bal a 6.0 25 -. is 4.0 ae iA ro) a Ba EG = i | S § & § fe = § & & g 5 g § & & TOU OM Mn sO Wi ee mo 9 aay 19 eye ee! BA rc OUR eimai sini | TEEPE LR OF a deal g g g g g 2 g 2 g g 2 2 £ 8 g g g OME On aoa EO Reena 10 0 2 8 tor PLO! GH ee NS OF oh ot ts a Ra Ca ROME Whe — Fa Bou oF de wis tlw at Figure 11 Number of Species and Wet Biomass on 0.5m Vertical Increments of Pile A Borers The wooden piles used for support, bracing, and fend- ers as part of Municipal Wharf No. 2, as well as the tim- bers of the sea walls, are pressure-creosoted Douglas fir. This treatment gives temporary protection from marine wood borers depending upon how completely the wood is impregnated with creosote. Some of the wooden piles remain serviceable for 25, years or more, but others, partic- ularly some of the fender piles subject to wear and abra- sion, must be replaced after 5 or 6 years. The timbers of the sea walls, after being in place for 17 years, are now beginning to fail as a result of borer attack. The most obvious and rapid damage to the wood occurs in the lower intertidal region of the piles and sea walls Wet Biomass per 0.5m? (kg) Page 68 and is due to attacks by the gribble Limnoria quadripunc- tata. Initial attack occurs some months or years after the wood is exposed to the sea water and after the creosote has leached out of the superficial layers. When piles are braced, the notches or bolt holes created during construc- tion often allow the gribbles immediate access to untreated or under-treated wood. Ultimately, the wooden piles are girdled and often severed by massive gribble attack. In the burrows of Limnoria, the amphipod Chelura tereb- rans Phillipi, 1839, is often found, but it is uncertain what role this animal plays in the destruction of the wood, if any. Subtidally, a few Limnoria are found in superficial bur- rows in the wood all the way to the bottom, but little struc- tural damage is done. Throughout this range, however, and especially at the mud line on the bottom, the wooden piles and sea walls are ultimately attacked by the ship- worm Bankia setacea (Tryon, 1863). The damage is so severe that the piles often break off at the mud line, es- pecially the fender piles. A detailed study on Bankia setacea in Monterey Harbor has been published (Haper- LIE & MELLOR, 1973). There is a number of molluscan borers which excavate burrows in the siliceous shale and calcareous stone found in and around Monterey Bay (HADERLIE, 1976). None of these, however, penetrate granite. Most of the aggregate used in the concrete piles under the wharf was granite gravel and these piles appear to have undergone little deterioration as a result of biological action over the past 50 years. So far in our studies we have found no borers in the concrete piles themselves. In the thick side wall plates of the giant barnacle Bala- nus nubilus, and the upper exposed valves of the rock oyster Pododesmus cepio, two common animals on the wharf piles, several boring organisms are found. The most common and destructive is the boring sponge Cliona ce- lata. Many of the older barnacles and rock oysters are se- verely infested with this sponge. In the massive fouling collars surrounding most of the piles in the lowest part of the intertidal area, the large Balanus nubilus are often piled up several layers thick, the oldest ones being at the bottom attached directly to the pile. These lower bar- nacles are often badly eroded by the sponge and so weak- ened that they collapse and allow massive portions of the collar to fall to the bottom. The sponge is found in the shell plates of both living and dead barnacles, but is more common in the dead shells. In one large living Balanus nubilus examined from Pile A at a depth of —4.0m, the sponge had penetrated through the bases of the lateral parapets but had not bored through the inner mantle layer. Many dead B. nubilus shells are also bored by the polychaete Dodecaceria fewkesi, and one living barnacle THE VELIGER Vol. 21; No. 1 was infested with these worms that had penetrated to the inner mantle layer. The phoronid Phoronis vancouveren- sis also burrows into the shell plates of Balanus nubilus and the upper valve of Pododesmus cepio. The only mol- luscan borers observed were the date mussel (Lithophaga plumula kelseyi) and the pholad Penitella conradi; in both cases these borers were found in burrows in the wall plates of dead Balanus nubilus. Recolonization of Concrete Piles One of the objectives of this investigation was to initi- ate the process of making long-term observations on the piles from which fouling growth had been removed and to record the recolonization of the concrete. These ob- servations will be continued for some years in an attempt to learn how long it takes for a new climax community to become established. The concrete piles subject to the detailed study described above were scraped clean of mac- roscopic organisms during the period between September 1974 and September 1975. In order to have a fixed starting period for observations on recolonization of the piles, the south faces of all the study piles were again scraped of all fouling growth in November 1975 and the settlement of organisms and gradual recolonization have been moni- tored regularly from that date until late May 1977. These observations will continue, but we will report here our findings over the initial 18 month period. On Pile A, the one studied from the highest tide level to the bottom, barnacles settled almost at once, Balanus glandula and Chthamalus dalli in the high intertidal area, Tetraclita squamosa rubescens in the mid-intertidal re- gion, and Balanus crenatus subtidally along practically the entire submerged length of the pile. Also throughout the intertidal area Ulva spp. soon covered the pile. Within a few weeks mature individuals of the anemones Antho- pleura elegantissima and Metridium senile were present in the mid- and low intertidal region, presumably having moved onto the bare concrete from the north face of the pile that had not been scraped. Subtidally, Phyllochaeto- pterus prolifica colonies were present after 6 months and large solitary Metridium were common. After 18 months the fouling population on Pile A was reestablished in most respects. The major difference be- tween the populations of organisms on the north, undis- turbed face of the pile and the south face which was scraped clean of macroscopic growth is the lack of identi- fiable Balanus nubilus on the south face of the pile. Also, the newly established Phyllochaetopterus colonies both in the low intertidal area and subtidally are still rather. small. High in the intertidal area new Balanus glandula are now up to 1.5,cm in basal diameter, and in the mid- Vol. 21; No. 1 intertidal zone Tetraclita up to 1cm diameter are com- mon. In place of the collar of Phyllochaetopterus and as- sociated animals at the 0.0 m tide level and below the pile now has a heavy growth of marine plants including Ulva spp., Gigartina exasperata, Neoagardhiella baileyi, Des- marestia ligulata, Dictyoneuropsis reticulata and Poly- neura latissima. Subtidally, among the anemones and worm tubes, are large slabs of the ascidian Aplidium soli- dum, and covering nearly everything is a thick growth of the bryozoan Bowerbankia gracilis. The other three study piles were scraped clean only on the south face of each pile in the the intertidal area down to the —o.5, tide level, so no subtidal observations during the past 18 months have been made. As in the case of Pile A, the scraped region of Pile B soon exhibited newly settled acorn barnacles and these have thrived, and the anemones Anthopleura elegantissima and Corynactis cali- fornica soon moved from the crowded north face to the south face of the pile. After 18 months the scraped part of the pile still appears sparsely populated, and much of the surface is covered with the encrusting bryozoan Cel- leporaria brunnea and the erect fuzzy Bowerbankia gracilis. No barnacles identifiable as Balanus nubilus have settled to date. Pile C never possessed the massive collar of Balanus nubilus so characteristic of most piles, although a few iso- lated individuals were present. After scraping, it slowly accumulated a population of the smaller acorn barnacles and anemones. After 18 months, the south face of this pile has a fouling growth much like the north face except there are no Balanus nubilus and the other acorn barnacles are smaller. Pile D, after being scraped, accumulated a vast number of the small brown barnacles Chthamalus dalli in the upper intertidal area, but very few Balanus glandula. Tet- raclita squamosa rubescens settled in the mid-intertidal region and are now 1cm in basal diameter. The lower part of the intertidal zone is dominated at present with masses of hydroids (especially Obelia spp.) and the ascid- ians Aplidium solidum and Ascidia ceretodes. Small col- onies of Corynactis californica, not present before scrap- ing, are now found on the concrete. None of the Phyllo- chaetopterus prolifica colonies have returned to the low intertidal region, and it is this feature, plus the presence of Corynactis, that distinguishes the south from the un- disturbed north face of this pile. THE VELIGER Page 69 SUMMARY 1. Monterey Municipal Wharf No. 2 was built 50 years ago on a combination of wooden and concrete pilings. The piles have collected a large and complex commu- nity of organisms which have not been subject to detailed study until now. 2. This report reviews the populations of organisms liv- ing on the piles and on the sea walls that have been added to the wharf in more recent years. In addition to a general survey of the piles of the entire wharf, a detailed qualitative and quantitative study of the organisms living on a few selected piles is reported on. 3. Since the construction of a marina in 1960, environ- mental parameters associated with the shoreward part of the wharf have been changed and the populations of wharf piling dwellers on this part of the wharf significantly altered. 4. After removal of all macroscopic fouling growth from the intertidal and subtidal area of selected concrete piles, the recolonization of these piles has been mon- itored and will be followed until a climax community is reestablished. Literature Cited Donat, Winrigtp III. 1975. Subtidal concrete piling fauna in Monterey Harbor, California. Unpubl. Masters Thesis, Naval Postgrad. School, Monterey, Calif. Haperum, Evcene CLinton 1968. Marine fouling and boring organisms in Monterey Harbor. The Veliger 10 (4): 327-341; plt. 49; 3 text figs. (1 April 1968) 1969. Merine fouling and boring organisms in Monterey Harbor. - II. Second year of investigation. The Veliger 12 (2): 182-192; 2 text figs.; 2 tables (1 October 1969) 1974. Growth rates, depth preference and ecological succession of some sessile marine invertebrates in Monterey Harbor. The Veliger 17 (Supplement): 1 - 35; 44 text figs. (1 June 1974) 1977. Fouling communities in the intertidal zone of wooden and con- crete pilings at Monterey, California. pp. 229-239 in: V. Romanov- sky (ed.), Proc. 4th Internat. Congr. Mar. Corrosion and Fouling Haperue, Evcene CLinTton & JoHN Conrap MELLoR 1973. Settlement, growth rates and depth preference of the shipworm Bankia setacea (Tryon) in Monterey Bay. The Veliger 15 (4): 265 to 286; 3 plts.; 6 text figs. (1 April 1973) Lanoz, Pzter S. 1968. Biological communities on concrete wharf pilings in Monterey Harbor. Unpubl. Res. Reprt., Naval Postgrad. School, Mon- terey, Calif Ricketts, Epwarp FE e« Jacx Carvin 1939. Between pacific tides. 320 pp.; illust. Stanford Univ. Press, Stanford, Calif, Page 70 THE VELIGER Vol. 21; No. 1 The Chromodoridinae Nudibranchs from the Pacific Coast of America. - Part III. The Genera Chromolaichma and Mexichromis HANS BERTSCH ' Donner Laboratory and Department of Zoology, University of California, Berkeley, California 94720 (2 Plates; Text figures 16 to 25) THE FIRST SEGMENT of this 4-part work (BERTSCH, 1977) examined the methodology of opisthobranch systematics, radular characteristics, and the supra-specific taxonomy of the Chromodorididae. Part II treated the 6 known species of Chromodoris from the Pacific coast of America (BERTSCH, 1978a). Chromolaichma Bertsch, 1977 A suite of characteristics is diagnostic for this new genus of Chromodoridinae nudibranchs with an elongate radula. The number of radular rows is at least 2 - 3 times greater than the maximum number of teeth per half-row; the width : length ratio is greater than 1: 3. A rachidian may or may not be present. The radular teeth are uni- cuspid, but denticles tend to remain small and on the outer lateral face throughout the entire tooth row. The outermost lateral teeth are flat blades (often elongate " Present address: Biological Sciences, Chaminade University of Honolulu, Honolulu, Hawaii 96816 along the antero-posterior plane), without denticles. The smooth outer teeth exhibit an ontogenetic increase: with larger radulae, there is a greater number of smooth outer lateral teeth. Type Species: Casella sedna Marcus & Marcus, 1967. Also included: Chromodoris dalli Bergh, 1879c¢; Chro- modoris punctilucens Bergh, 1890; and Chromodoris youngbleuthi Kay « Young, 1969. Chromolaichma sedna (Marcus & Marcus, 1967) comb. nov. (Figures 3-G, 16, 18 - 21, 47 - 50) References and Synonymy: Casella sedna Marcus & Marcus, 1967: 178-181; figs. 34-37 Chromodoris fayae LANCE, 1968: 3-6, figs. 1-5 Glossodoris sedna (Marcus & Marcus). ABBOTT, 1974: 355 Chromodoris sedna (Marcus & Marcus). BerTscH, 1970: 8. BertscH, 1971: 16. KEEN, 1971: 822; plt. 20, fig. 5. SPHON &@ MULLINER, 1972: 150-151. SPHON, 1972b: Explanation of Figures 57 to 56 Scanning Electron Micrographs of the Radular Teeth of Chromolaichma dalli and Mexichromis porterae Figure 51: Chromolaichma dalli; jaw elements (HB 38 A) 3850 Figure 52: Chromolaichma dalli; rachidian and innermost lateral teeth. A fair amount of tooth wear (broken and rounded cusps) is visible (HB 38 A) X1300 Figure 53: Chromolaichma dalli; outer denticled lateral teeth (HB 38 A) X%1300 Figure 54: Chromolaichma dalli; smooth outermost lateral teeth (HB 38 A) 1300 Figure 55: Mexichromis porterae; innermost lateral teeth (HB 390 A) X8oo Figure 56: Mexichromis porterae; lateral teeth (HB 390 A) X800 Vol. 21; No. 1 59. Bertscu et al., 1973: 289, 292, 293. BERTSCH, 1973: 108. Brusca, 1973: 174. KEEN & CoAN, 1975: 43. BirKELAND, Meyer, STAMES, & BurorD, 1975: 67. Bertscu, 1976a: 121. BeERtscH, 1975b: 157 Material Examined and Distribution: Baja California, Gulf coast 1) 1 specimen, 12m subtidal, Bahia de Los Angeles; leg. D. K. Mulliner, 17 - 18 May 1975 2) 1 specimen, 6m subtidal, Isla Bargo, Bahia Concepcién; leg. A. J. Ferreira, 29 July 1974 (CAS) 3) 5 specimens, Isla Bargo, Bahia Concepcién; leg. A. J. Ferreira, 29 July 1974 (HB 371 A-B) 4) 3 specimens, Nopolo and Juncalito; leg. H. Bertsch, M. Ghiselin, and J. Allen, 27 June 1974 (HB 91 A-C) 5) 2 specimens, intertidal, Tizate, 8km N of Bahia Escon- dido; leg. H. and J. DuShane, 6 February 1971 (LACM A 8530) 6) 1 specimen, intertidal, 1okm N of La Paz, road to Pichilinque; leg. A. G. Smith and A. E. Leviton, 11 Jan- uary 1959 (CAS) 7) 2 specimens, 2- 3m subtidal, Bahia Carisalito; leg. H. Bertsch, 23 July 1972 8) 1 specimen, N. Isla Cerralvo; leg. H. Bertsch, 24 July 1969 9) 1 specimen, subtidal, W anchorage, Isla Cerralvo (24° 10’N; 109°55’ W) ; leg. J. H. McLean, P Oringer and L. Marincovich, 9 April 1966 (LACM 66-25) 10) 3 specimens, SW Isla Cerralvo; leg. H. Bertsch, 25 July 1972 (HB 18 A-C) Ir) 1 specimen, 1.6km N of Cabo Pulmo; leg. 17 May 1971, R/V Searcher (LACM) ¥2) 1 specimen, Cabo Pulmo; leg. C. Gage et al., 25 - 26 May 1971 (HB 386; LACM) Mainland Mexico: 13) 1 specimen, Puerto Penasco, Sonora; leg. H. Bertsch and G. G. Sphon, November 1967 14) 8 specimens, Puerto Penasco; leg. H. Bertsch, 15 July 1975 (HB 270 A- H) 15) 6 specimens, Puerto Penasco; leg. H. Bertsch, 21 July 1975 (HB 276 A-F) 16) 9 specimens, Puerto Penasco; leg. H. Bertsch and P C. Cook, 22 July 1975 17) 18 specimens, Puerto Penasco; leg. H. Bertsch and P C. Cook, 23 - 24 July 1975 (HB 284 A-S) 18) 2 specimens, Puerto Pefiasco; leg. H. Bertsch, 23-29 December 1975 (HB 341, 348) 19) 1 specimen, Puerto Penasco; leg. P. Pickens, 1964 (US NM F 909) 20) 1 specimen, intertidal, Bahia San Carlos, Sonora; leg. R. Poorman, November 1975 (LACM) 21) 2 specimens, intertidal, Punta Mita, Nayarit (20°46’N; 105°33’ W) ; leg. G. G. Sphon 21 - 23 January 1970 (LA CM) THE VELIGER Page 71 Central and South America: 22) 1 specimen, 8 - 12subtidal, N side Isla del Cano, Punt- arenas, Costa Rica (8°43/15”N; 83°53'07” W); leg. J. H. McLean and J. Wheeler, 14 - 19 March 1972 (LACM) 23) 1 specimen, 6m subtidal, Isla Siboga, Islas de las Perlas, Panama; leg. K. B. Meyer, 20 May 1972 (HB 265) 24) 5 specimens, intertidal, 2.4km E of Darwin Research Station pier, S Isla Santa Cruz, Galapagos Islands; leg. K. Koford, 9 February 1964 (CAS) 25) 1 specimen, Darwin Research Station, Galapagos Is- lands (0°45'06”S; g0°15’38”W); leg. G. G. Sphon, March 1971 (HB 268; LACM 71-45) The type locality of Chromolaichma sedna is Puerto Penasco, Sonora, Mexico. Its known occurrence is from Puerto Penasco to the Galapagos Islands. It has been reported from numerous intermediate localities: Bahia San Luis Gonzaga, Isla Angel de la Guarda, Isla Santa Cruz, Isla Cerralvo, and Las Cruces (all Baja California); Guaymas, Sonora; Mazatlan, Sinaloa; Santa Cruz, Nayarit; Tenacatita, Ja- lisco; Colima; and Costa Rica (LaNcE, 1968: 6; SPHON & MULLINER, 1972: 150; BertscH et al., 1973: 293). This species had been reported previously from the Gala- pagos Islands based on only one specimen (SPHON & MULLINER, 1972: 150; lot 25 of this study), so the addi- tional specimens (lot 24) from its southern range extremi- ty are significant. External Morphology and Coloration: The largest living specimens measured 48 and 58mm long (new size records; previously reported greatest length while crawling was 47mm; cf. LancE, 1968: 3). Seventy- three specimens measured at Puerto Penasco (July and December 1975), and Nopolo and Juncalito (June 1974) ranged from 10 - 58mm total length alive (X = 24.3mm). Body color is pure white. Three color bands surround the notum and foot, an inner opaque white, a middle one of vivid red, and a marginal edging of brilliant yellow. The rhinophores and gills are white basally, with deep red on the distal 4 to #’s of their length. Gills are usually held erect, often with the free portions waving back and forth (increasing water flow across and oxygen availabil- ity to the simply branched gills). KEEN (1971: plt. 20, fig. 5) presents a color photograph of the animal. Radula: Despite the common occurrence of Chromolaichma sedna, reports of only 2 radular formulae are in the lit- erature (Marcus & Marcus, 1967: 180; Lance, 1968: 5). Table 8 presents radular data and means from 51 additional specimens. The combined radular formula is Page 72 d THE VELIGER Vol. 21; No. 1 Table 8 Radular variation in Chromolaichma sedna Width: Number Maximum number Maximum number Specimen Length Width length of tooth of teeth of teeth per (HB numbers) (in mm) (in mm) ratio rows per half-row per half-row 2 — = — 130 55 35 3 Be ah = 129 42 13 USNM F 909 — — — 120 52 32 18 A 2.99 1.03 1:2.90 98 40 6 18 B 4.13 1.19 1:3.46 100 46 23 18C _ = = 87 43 8 67 4.3 1.15 1:3.74 109 42 20 91A 6.34 2.06 1:3.08 112 61 26 91B 5.74 1.82 1:3.15 105 36 14 91C 4.75 1.82 1:2.61 102 60 15 265 1.58 0.46 1:3.43 71 25 1 268 1.15 0.42 1:2.74 74 25 0 270 A 1.96 0.63 1:3.11 78 29 4 270 B 2.323 0.73 1:3.18 91 38 8 270 C 2.85 0.97 1:2.94 89 37 11 270 D 3.62 1.29 1:2.81 102 46 24 270 E 1.68 0.59 1:2.86 74 28 3 270 F 2.28 0.81 1:2.81 87 36 5 270 G 2.04 0.65 1:3.14 82 39 5 270 H 3.56 1.13 1:3.15 110 43 16 276 A 3.08 0.86 1:3.58 107 33 4 276 B 2.28 0.91 1:2.51 89 37 7 276 C 2.97 0.97 1:3.06 93 4l ll 276 D 2.42 0.95 1:2.55 85 39 6 276 F 1.88 0.63 1:3 83 35 2 279 A 2.89 0.93 1:3.11 96 47 15 279 B 2.22 0.75 1:2.96 - 86 31 3 279 C 2.67 0.79 1:3.38 96 34 3 279 D 4.38 1.41 1:3.11 120 51 35 279 E 3.49 1.11 1:3.14 98 46 19 279G 2.65 0.89 1:2.98 93 39 14 279 H 2.32 0.85 1:2.73 93 37 3 279 I 3.64 1.21 1:3.01 110 46 12 284 B 4.12 1.45 1:2.84 108 55 28 284 C 5.17 1.66 1:3.11 137 49 30 284 D 2.1 0.81 1:2.59 74 32 8 284 E 3.62 1.05 1:3.45 107 43 17 284 F 3.27 1.01 1:3.24 94 39 4 284 G 1.98 0.79 1:2.51 80 35 3 284 H 2.81 1.01 1:2.78 96 41 2 284 I 3.15 0.99 1:3.18 98 37 3 284 J 1.62 0.61 1:2.66 66 30 2 284 K 2.53 0.85 1:2.98 83 39 2 284 M 2.06 0.81 1:2.54 87 33 6 284 N 2.69 1.03 1:2.61 9) 40 2 284 O 2.99 1.03 1:2.9 95 36 3 284 P 3.17 1.23 1:2.58 99 42 9 284 R 2.08 0.71 1:2.93 82 33 1 341 4.52 1.47 1:3.07 89 43 16 348 2.16 0.65 1:3.32 76 28 1 371 A 6.59 2.34 1:2.82 124 70 39 371 B 6.32 1.9 1:3.33 131 62 39 386 C 4.71 1.37 1:3.44 109 46 17 X 3.18 1.057 1:3.002 96.698 40.98 11.98 s 1.308 0.4167 0.304 16.41 9.486 10.95 2Marcus & Marcus, 1967; 3LANceE, 1968. Tue VELIGER, Vol. 21, No. 1 [BerTscH] Figures 51 to 56 Figure 54 - e “aa <2 f _f * Figure 55 Figure 56 Vol. 21; No. 1 e tb Bo aS ee ‘y yu 16-H 16-I 16-K Q | Figure 16 Radular teeth of Chromolaichma sedna A - USNM F 909; rachidian and innermost lateral teeth, row 109 B — HB 270 B; rachidian tooth; 0.02mm long, 0.008mm wide C — HB 91 C; dorso-lateral view of rachidian tooth, row 93 D — HB 270 C; dorsal view of aberrant rachidian tooth, with 3 accessory denticles on each side of main cusp; row 18; LBM, 0.042 mm 66-131 (28-70:1°28-70). The number of smooth outermost laterals varies from 0 to 39. Least squares regression analysis proves that the maxi- mum number of teeth per halfrow increases with the greater number of tooth rows (Figure 18). The regression line formula is Y=~2.53+0.45 X. The coefficient of correlation is 0.7783 (P < 0.001, n=53). The number of tooth rows increases with the greater length of the radula (Figure 19). The equation, Y= THE VELIGER Page 73 16-N ie 16-O E - HB a: CG; outer face of innermost lateral tooth, row 93, LSR F — HB 341; outer face of innermost lateral tooth, row 37, LSR G - HB 341; lateral view of tooth 6, row 64, LSR; length of shaft, 0.04mm; LBM, 0.o69mm H - USNM F goo; outer face of tooth 18, row 109, LSR I — USNM F go9; outer face of tooth 18, row 109, LSR J — HB 270 A; outer face of tooth from anterior portion of radula; LBM, 0.04 mm K - HB 284 B; distal portion of outer lateral tooth with a single denticle L - HB 341; 3 outermost lateral teeth, row 36, RSR M — HB 341; developing tooth, 2™4 from outer edge of radula, penultimate row, RSR; LBM, 0.028mm N - HB 341; developing tooth, 7'* from outer edge, penultimate row, RSR; LBM, 0.057 mm O —- HB 341; developing teeth, 4" (upper) and 5% tooth from outer edge of radula, 3" last row; LBM, 0.051 mm 63.32+ 9.985 X, describes the regression line with r= 0.8594, P < 0.001, and n = 49. The radular width and the maximum number of teeth per half-row are positively correlated (Figure 20); Y = 18.92 +20.34 X, r=0.8913, P < 0.001, n= 49. The number of smooth outermost lateral teeth is also dependent on the size of the radula (Figure 21). The num- ber of tooth rows and the maximum number of smooth laterals are positively correlated (r = 0.8142, P < 0.001, Page 74 17-C 17-A d 17-B I 7-D I 7-E I 7-F 17-G 17-H 17-1 an, 17-J \ 17-L 1-7K THE VELIGER Vol. 21; No. 1 I 7-M | | 17-N as 17-Q 17-P | 17-R ; 17-S Figure 17 Radular teeth of Chromolaichma dalli A — HB 38 B; outline sketch of entire radula, before flat mounting; LBM, 3mm B - HB 285 G;; rachidian tooth, 0.016mm wide C — HB 38 B; rachidian tooth D - HB 324 C; ventro-lateral view of tooth 2, row 132, RSR E -— HB 324 C; ventral view of innermost lateral tooth, row 132, LSR F - HB 324 B; 3° lateral tooth, row 1; LBM, 0.075mm G - USNM F 908; 8% lateral tooth, row 59, RSR H - USNM F 908; ventro-lateral view, outer face of tooth 12, row 30, RSR I - USNM F 908; dorso-lateral view, tooth 14, row 34, RSR J - HB 38 B; tooth 16, row 50, RSR K —- HB 324 C; tooth 17, row 60, LSR; LBM, 0.127mm L - HB 324 C; dorso-posterior view, teeth 8 and 9, approximately tow 140, LSR M - HB 324 B; tooth 15, row 11, RSR N - HB 324 B; tooth 18, row 121, LSR; LBM, 0.056mm; length of base, 0.o69mm O - HB 324 D; an outer lateral tooth, row 46, LSR P — USNM F 908; 24 tooth from outer edge, row-36, RSR Q - USNM F 908; outermost lateral tooth, row 38, RSR R — HB 324 B; outer lateral tooth, approximately row 30 S — HB 38 B; outer laterals, teeth 28 - 32, drawn to relative pro- portion and position, row 50, RSR Vol. 21; No. 1 Maximum number of teeth/halfrow 80 Number of rows 100 120 Number of rows 140 120 100 THE VELIGER Page 75 4 Length of radula (mm) (< adjacent column) Figure 18 Correlation between maximum number of teeth per half-row and number of tooth rows. A. Chromolaichma dalli (open circles) ; B. Chromolaichma sedna (dots) ; open triangle is holotype of Chro- molaichma dalli n= 53). The regression line formula is Y = -40.56+ 0.543 X. The most anterior portion of the radula is pointed, caused by tooth wear and loss of lateral teeth. Rachidian tooth is present (Figures 16 A - C, 47) ; one radula had an aberrant rachidian tooth with 3 small den- ticles flanking a central cusp (Figure 16 D). The first later- al tooth has 1-4 denticles on the inner face, and 5-8 on the outer face (Figures 16 E - F, 47). Succeeding lateral teeth (Figures 16 G-J, 48) have sharp, recurved shafts. There is an increasing number of denticles on each tooth throughout the first 10 - 20 teeth, and then a decrease in their number until the smooth outermost laterals are reached. Excluding the smooth laterals, denticles on the outer face of lateral teeth from row 34 of specimens HB 270 A and 341 ranged from 2-8 (K—5.4, n=41). Some radulae may have g- 10 denticles on the lateral teeth (Figure 48). 5 6 7 8 Figure 19 Relation between number of tooth rows and length of radula, Chrc- molaichma dalli and Chromolaichma sedna. Symbols as in Figure 18 Page 76 Maximum number of teeth/halfrow 0.5 1.0 1.5 2.0 Width of radula (mm) Figure 20 Correlation between maximum number of teeth per half-row and width of radula, Chromolaichma dalli and Chromolaichma sedna. Symbols as in Figure 18 Figure 4g illustrates the transition zone between denti- cles and smooth teeth. There is a reduction in the number and prominence of denticles; the shaft of the tooth is still hook-like, but very shortly the following lateral teeth be- come blade-like (Figures 16-L and 45). The outermost teeth in 2 radulae had a slight notch (almost a small denticle) just below the cusp (Figure 16-K). The length of the cusps of the denticled teeth across a half-row (specimen HB 341) varied from 0.012 - 0.038 mm (X=0.0235mm, n= 19). The small size of the lateral denticles is shown by the ratio of lengths of the first denticle : cusp. The cusp ranged from 6.67 to 19 times longer than the first denticle (XK = 8.99, s = 3.396, n = IQ). Figure 16 M - O illustrates developing lateral teeth. As growth proceeds, the tooth increases in length and thickness (strength) of the shaft. THE VELIGER Vol. 21; No. 1 do oO > fo} fo} [o) o) Maximum number of smooth teeth/halfrow fo) 80 100 120 140 160 Number of rows Figure 21 Correlation of maximum number of smooth teeth per half-row and number of tooth rows, Chromolaichma dalli and Chromolaichma sedna. Symbols as in Figure 18 Discussion: Chromolaichma sedna was originally named in the ge- nus Casella; later transferral to the genus Chromodoris was appropriate at that time given the understanding of the latter 2 genera. Now, however, with the examination of many radulae from all the known Chromodoridinae species from the American Pacific, the data indicate clear- ly that a new genus should be established to accommodate this species and other similar species. This new genus is not monotypic, but encompasses at least 3 (probably 4) species; moreover, the generic diagnosis is based on a suite of characteristics that affect the entire radula, and are readily differentiable from other nudibranch genera. Chromolaichma dalli Bergh, 1879, comb. nov. (Figures 3-H, 18-21, 51 - 54) References and Synonymy: Chromodoris dalli BERcH, 1879c: 72, 109-112. BERGH, 1878c: 3 (nomen nudum). Bercu, 18792: 3 (nomen nudum). Bercu, 1880: plt. 13, figs. 1-7; plt. 14, figs. 1-4. BeErcH, 1891: 141. Berou, 1892: 118. Berou, 1898: 533. CocKERELL & ELIoT, 1905: 36. Mac- Vol. 21; No. 1 THE VELIGER Page 77 FARLAND, 1906: 129. MacFArLanp, 1966: 154; pit. 12) 1 specimen, intertidal, Isla San Francisco; leg. G. G. 34, figs. 10-11. Marcus « Marcus, 1967: 176. Sphon, 1 April 1974 (HB 385; LACM) SpHon, 1972b: 59. Bu ioom, 1976: 292. BertscH, 173) 1 specimen, Los Islotes; leg. A. J. Ferreira, 16 August 1976b: 158 1973 (HB 374) Glossodoris dalli (Bergh). O’DonocHuE, 1926: 211. PRu- 14) 1 specimen, middle of E side of Isla Espiritu Santo; leg. voT-FoL, 1951a: 95-96. STEINBERG, 1963: 69. AB- A. J. Ferreira, 19 August 1973 (CAS) BOTT, 1974: 355. 15) 2 specimens, intertidal, 6km N of La Paz; leg. A. G. Chromodoris banksi FARMER, 1963: 84; plt. 1b; text figs. 1 Smith and A. E. Leviton, January 1959 (CAS) f-k. Farmer, 1967: 341. Marcus « Marcus, 1967: 16) 6 specimens, intertidal, 9.6km N of La Paz; leg. A. G. 175-176,237. SKOGLUND,1970: 429. BERTSCH, 1970: Smith and A. E. Leviton, January 1959 (CAS) 8. KEEN, 1971: 822. SPHON, 1972a: 5 (color photo- graph). SpxHon, 1972b: 59. Bertscu et al., 1973: Mainland Mexico: 287 - 289, 292. Keren « Coan, 1975: 43. BERTSCH, 1976b: 157 17) 2 specimens, Puerto Pefiasco; leg. S. S. Berry, 8 - 9 March Glossodoris banksi (Farmer). ABBOTT, 1974: 355 1949 (CAS) Chromodoris banksi sonora Marcus & Marcus, 1967: 173 18) 1 specimen, Puerto Pefiasco; leg. P. Pickens, 1964/1965 to 176; figs. 25-29; 237. KEEN, 1971: 822, fig. 2329. (USNM F 908) Chromodoris sonora Marcus « Marcus. SPHON, 1972b: 53, 59 19) 1 specimen, intertidal, Puerto Pefiasco; leg. H. Bertsch and G. G. Sphon, November 1967 Chromolaichma dalli (Bergh). BertscH & MEYER, in prep. 20) 1 specimen, Puerta Penasco; leg. D. Mulliner, December Bertscu et al. (1973) synonymized Chromodoris banksi sonora 1970 Marcus « Marcus with C. banksi Farmer. The new synonymization 21) 3 specimens, Puerto Pefasco; leg. H. Bertsch, 21 July of banksi with dalli will be substantiated in the discussion of 1975 (HB 275 A-C) Chromolaichma dalli. 22) 6 specimens, Puerto Penasco; leg. H. Bertsch, 22 - 23 July 1975 (HB 278 A-F) 23) 10 specimens, Puerto Penasco; leg. H. Bertsch and P C. Material Examined and Distribution: Cook, 24 - 26 July 1975 (HB 285 A-J) ; F : ; 2. 2 specimens, Puerto Penasco; leg. H. Bertsch, 28 Jul Pacific coast of Baja California: 2 Beis 290 A-B) : ae 25) 7 specimens, Puerto Penasco; leg. H. Bertsch and P C. Cook, 5 - 9 August 1975 (HB 297 A-G) 26) 2 specimens, Puerto Pefiasco; leg. H. Bertsch and S. Pohlman, 18 - 20 August 1975 (HB 305 A - B) 27) 2 specimens, Puerto Pefiasco; leg. H. Bertsch and S. Pohlman, 21 August 1975 (HB 312 A-B) 28) 6specimens, Puerto Pefiasco; leg. P. Pickens, various dates 1) 1 specimen, Man-of-War Cove, Bahia Magdalena (24° 37-5 N; 112°7.5’ W); leg. J. H. McLean and F LaFollette, 31 October 1971 (LACM 71-183) Gulf coast of Baja California: 2) 2 specimens, 1.6km N of Puertocitos; leg. H. Bertsch, T. Gosliner & G. Williams, 29 March 1972. (HB 324 A-F; USNM 753562) 3) 5 Specimens, intertidal, N end of “Turtle Pen,” Isla Co- 29) 1 specimen, Puerto Pefiasco; leg. H. Bertsch, 27 Decem- ronado, Bahia de Los Angeles; leg. G. G. Sphon and D. ber 1975 (HB 349) Mulliner, May 1976 (LACM) go) 1 specimen, gm subtidal, Bahia San Carlos; leg. A. J. 4) 2 specimens, 12-18m subtidal, on reef between Islas Ferreira, August 1972 (HB 373) Calaveras and Smith, Bahia de Los Angeles; leg. D. Mul- 31) 3 specimens, intertidal, Bahia San Carlos; leg. R. Poor- liner, May 1976 (LACM) man, November 1975 (LACM) 5) 1 specimen, Isla San Marcos (25°30’N; 111°W); leg. 32) 1 specimen, La Cruz, Nayarit; leg. R. Poorman, 3 Jan- E. Janss, Jr., April 1974 (LACM) uary 1976 (LACM) 6) 1 specimen, 22km S of Mulege; leg. H. Bertsch and B. 33) 3 specimens, Jalisco; leg. R. Poorman, January 1976 (LA Rose, 21 December 1973 (HB 37) CM) 7) 2 specimens, 22km S of Mulege; leg. H. Bertsch and B. Rose, 21 December 1973 (HB 38 A -B) Previous collecting records have been throughout the 8) 1 specimen, Punta Aguja, mouth of Bahia Concepcion; Gulf of California and in Costa Rica (BertscuH é¢ al., leg. A. J. Ferreira, 28 July Hoyle MELE gag) 1973: 289) The specimen from Bahia Magdalena (lot 9) us eee Coyote Cove, Bahia Concepcién; leg. D. 1) represents the first record of Chromolaichma dalli from iner, 19- 20 May 1975 Heapae PiBaa Galifomarith : fan 10) 1 specimen, subtidal, Nopolo (Loreto area); leg. H. ae ei coast Sl ae ae gt ay 1} eens oa a Bertsch, 27 June 1974 (HB 90) southern Mexico (lots 32 and 33) are intermediate local- rr) 1 specimen, Arrecife San Marcial, S of Puerto Escondido; ities between the southern Gulf of California and Costa leg. A. J. Ferreira, 15 June 1974 (HB 365) Rica. Page 78 THE VELIGER ; Vol. 21; No. 1 Table 9 Radular variation in Chromolaichma dalli Width: Number Maximum number Maximum number Specimen Length Width length of tooth of teeth of smooth teeth (HB numbers) (in mm) (in mm) ratio rows per half-row per half-row ¢ — = = 124 32 8 USNM F 908 ~ = = 103 39 5 5 6.0 125 1:4 150 41 13 37 3.82 1.17 1:3.26 114 36 15 38 B 5.88 1.41 1:4.17 115 36 16 90 7.77 2.16 1:3.597 120 43 22 275A 5.31 1.13 1:4.69 142 29 8 275 B 5.49 1.35 1:4.07 132 37 17 psy (C; 2.42 0.73 1:3.32 95 29 6 278 A 3.92 1.62 1:2.42 100 42 21 278 B 5.47 1.23 1:4.45 143 36 16 278 C 4.97 1.25 1:3.98 130 33 15 278 D 6.44 1.64 1:3.93 144 39 19 278 E 3.19 0.77 1:4.14 118 25 4 285 A 5.86 1.25 1:4.69 126 34 15 285 B 7.39 1.8 1:4.11 149 38 17 285 C 3.535 0.707 1:5 111 28 9 285 D 4.36 1.09 1:4 129 30 12 285 E 4.99 1.07 1:4.66 140 33 12 285 F 5.555 1.212 1:4.58 137 32 11 285 G Well 1.74 1:4.43 156 42 18 285 H 2.89 0.707 1:4.09 113 26 7 285 I 4.65 1.09 1:4.27 131 34 16 285 J 3.96 0.99 1:4 111 29 7 290 A 5.21 1.29 1:4.04 Bel28 33 15 290 B 5.555 1.15 1:4.83 135 31 8 297 A 4.67 1.01 1:4.62 126 30 8 297 B 4.2 1.03 1:4.08 120 27 13 297 C 5.84 1.33 1:4.39 139 35 13 297 D 3.98 0.91 1:4.37 116 31 13 297 E 3.43 0.83 1:4.13 106 28 11 297 F 6.0 1.37 1:4.38 149 35 16 297 G 6.26 1.47 1:4.26 130 38 17 305 A 3.33 0.77 1:4.32 102 28 8 305 B 4.77 1.07 1:4.46 137 29 9 312A 3.23 0.77 1:4.19 98 26 8 324A 5.86 1.43 1:4.1 136 36 _ 324B 7.07 1.74 1:4.06 153 43 23 324 C 6.18 1.52 1:4.07 155 38 — 324 D 6.95 1.76 1:3.95 151 40 _ 324 F 8.26 1.74 1:4.75 153 40 16 349 2.16 0.51 1:4.24 90 23 364 1.6 0.36 1:4.44 75 19 1 365 Tee, 1.98 1:3.9 153 45 20 373 3.9 0.95 1:4.11 111 31 14 374 6.54 1.72 1:3.8 123 37 16 385 2.65 0.51 1:5.2 98 21 2 x 5.043 1.219 1:4.19 125.89 33.34 12.34 s 1.634 0.414 0.467 19.734 6.07 5.451 4FARMER, 1963; "Marcus & Marcus, 1967. Vol. 21; No. 1 External Morphology and Coloration: Reported lengths of living Chromolaichma dalli are 15, 24, 33mm. Twenty specimens that I measured varied from 14 to 46mm long (X = 27.5mm), including speci- mens 37, 38, 39, and 43mm long. Notal and foot back- ground color is white. Brown-black spots of varying size are on the notum and sides of the body. Larger specimens tend to have more numerous, smaller black dots, and the background becomes grayish around the center of the dor- sum. Cream-colored and occasionally orange (red in larger specimens) spots are mixed among the blackish dots on the notum. Gills and rhinophores are white, tipped orange or light red distally. The color variation between small and large animals is shown by the photographs in FARMER (1963) and SpHON (19724). Radula: Data from the literature and my own investigation are in Table 9g. The combined radular formula is 75 - 156 (19 - 45°1°19- 45). There are from 1- 22 smooth outer- most lateral teeth. Data from Bercu (1879c: 112 tooth rows, 29 teeth per half-row, with 6 smooth teeth per half- row) were not used in the regression analysis, but are plotted in the graphs (Figures 18 - 21). The maximum number of teeth per half-row is depend- ent on the number of tooth rows (Figure 18). The regres- sion formula is Y= 7.61 +0.204 X (r=o0.664, P< 0.001, n= 47). The radular length and number of tooth rows (Figure 19) are positively correlated (Y = 74.18+10.36 X; r= 0.8525, P < 0.001, n= 45). A positive correlation exists between ihe radular width and the maximum number of teeth per halfrow (Figure 20). The regression line formula is Y = 16.09+ 14.08 X; T= 0.9471,P < 0.001, n= 45). The number of smooth outer lateral teeth per half-row is dependent on the number of tooth rows (Figure 21). The equation Y= -8.89+0.17 X describes the regres- sion line (r = 0.6083, P < 0.001, n= 44). Comprehensive jaw and radular descriptions are in Bercu (1879c: 111) and Marcus & Marcus, (1967: 175). Jaw elements are bent rods, bifurcated at the inner end (Figure 51). Figure 17 A illustrates an entire radula before flatten- ing. A rachidian tooth is present, with a triangular cusp that subtends an acute angle with the base anteriorly, and a right angle posteriorly. The postero-dorsal edge of the cusp varies between being smoothly concave (FARMER, 1963: fig. 1k), to deeply concave with a median point (Figure 17 B), slightly concave with a median notch THE VELIGER Page 79 (Figure 52; cf. also Bercu, 1880: plt. 13, fig. 11; plt. 14, fig. 2) to slightly convex with either a median prominence (Figure 17C), or a median prominence flanked by a similar prominence on each side (Marcus & Marcus, 1967: 174; fig. 28R). Inner lateral teeth (Figure 52) have up to g - 10 denticles on the outer face (Figure 17 D-L) increasing in number towards the middle of the denticled teeth, then decreasing closer to the smooth out- ermost teeth. Laterals near the outer smooth denticles sometimes have denticles on their posterior surfaces (Fig- ure 53 and 17 M-N). Outermost lateral teeth are smooth, lacking denticles, and flattened along the antero-posterior plane (Figures 54 and 17 O-S). The length of the cusp increases the farther the tooth is from the innermost part of the halfrow. The cusp length averaged 0.0176mm (range, 0.006 - 0.03mm; n= 18). The length ratios of first denticle : cusp averaged 1 : 11.9 (range, 4 - 30; n= 18, s= 7.735). Discussion: Since coloration is an essential characteristic to classify chromodorid nudibranchs, new taxa should be erected only after having observed the living animal. Bergh de- scribed Chromolaichma dalli based only on preserved material. I have seen numerous specimens of authentic Chromodoris banksi that match Bergh’s description. Al- though the color will often fade in preservative solutions, preserved specimens of this species retain for some time hints of the original colors in life. Because of this, one can State that there are no color differences between the 2 nominal species. e The radula is even more diagnostic. The morphology is identical (compare Bergh’s, the Marcus’s, Farmer’s and my figures), and the meristic characters also match. In the relation of number of tooth rows to maximum number of teeth per half-row Bergh’s specimen plots right in the middle of the Chromodoris banksi specimens (Figure 18). A similar situation holds for the relation between the num- ber of tooth rows and the maximum number of smooth outermost teeth per half-row. Marcus « Marcus (1967: 176) state that dalli is related to their new subspecies, but that “the total of 15 branchial plumes, and the rachidian pseudo-tooth divided into two halves by a longitudinal groove, separate dalli from banksi sonora.” Their subspecies has been suppressed ; the original description of Chromodoris banks: was of specimens with 9 gills. The range of variation of C. banksi gills is from 9 - 34. Bergh’s specimen lies well within this range, so that the number of branchial plumes cannot give evidence of 2 different species. Differences in the rachidi- an tooth are also within the range of intraspecific varia- tion (cf. radula description above). Page 80 There are no specific differences between Bergh’s Chro- modoris dalli and Farmer’s C. banksi. Therefore, I propose that Chromodoris banksi is a junior subjective synonym of the older Chromolaichma dalli. Bergh described Chromolaichma dalli from the Puget Sound area of Washington. However, no further speci- mens have ever been reported from the coasts of Califor- nia, Oregon, Washington, nor Canada. The collection of the Friday Harbor Marine Laboratories (in the Puget Sound area) contains no specimens of C. dalli (Dr. Eu- gene Kozloff, personal communication). The Chromodori- dinae is a tropical group, which gives strong zoogeograph- ical evidence against the correctness of Bergh’s locality data. Bergh’s specimen had probably come from the Gulf of California, but was mislabeled. Such a situation is not uncommon in the older literature (Mayr, 1969: 375-377; EMERSON & JACOBSON, 1976: 9, 119). As first reviser, I propose that the type locality of Chromodoris dalli Bergh, 1879, be changed to 2.3 miles (3.68km) south of Puerto- citos, and thereby reflect the correct distribution of this species. This type locality corresponds to that given for Chromodoris banksi by FARMER (1963). Discussion of Chromolaichma The 2 species of Chromolaichma, C. sedna and C. dalli, can be readily separated on the basis of external colora- tion. Chromolaichma sedna is pure white, with 3 marginal color bands; C. dalli is covered with numerous blackish dots, with an orange band around the notal edge. Table 10 Results of t-tests conducted between the species of American Pacific coast Chromolaichma. Numbers are significance probabilities (P). N.S.: not significant, no difference between the species for the particular measurement or count. Chromolaichma: dalli sedna Rows/teeth <0.001 Length/rows N.S. Width/teeth N.S. Rows/smooth teeth <0.001 Length <0.001 Width N.S. W:L ratio <0.001 Rows <0.001 Max. teeth <0.001 Smooth teeth N.S. THE VELIGER Vol. 21; No. 1 Radular meristic characters differ significantly (Table 10). The means used to calculate the t-tests are given in Tables 8 and 9. The radula of Chromolaichma dalli is longer and has more tooth rows than C. sedna. These are not ontogenetic differences because the maximum number of teeth per halfrow (a meristic quality that increases dependent upon the larger number of tooth rows for each species) is smaller in C. dalli and both species have the same maximum number of smooth outermost laterals per half-row. Mexichromis Bertsch, 1977 Distinct radular tooth morphology characterizes this new genus. The radular teeth are acuspid, with pectinate denticulation (Figures 1 C, 22, 55 and 56; MacFarLanp, 1966: plt. 34, figs. 24, 25, 27, 28). This group is unique, because the distal portion of the shaft does not have a strong cusp that is longer and thicker than the succeeding denticles. The distal structure should be termed a denticle, since it is equal in length and thickness (or shorter and thinner) than some of the succeeding denticles. This is not a character affecting just a few innermost nor outer- most lateral teeth, but is a pattern that can be seen throughout the majority of the radula. Moreover, the a- cuspidate shape is not a minor morphological trait, but a major structural and functional change. The strong rasping or gauging cusp is absent, replaced by a series of picking or sawing points (narrow, elongate denticles). Type Species: Chromodoris antonii Bertsch, 1976 Also included: Chromodoris porterae Cockerell, 1901, and Chromodoris tura Marcus & Marcus, 1967. During recent years, the latter 2 species have had fre- quently changing taxonomic placements. Marcus & Mar- cus (1967: 56) comment on the difficulty of generically classifying their new species. Establishing this new genus resolves the either-or alternatives by recognizing the u- niqueness of, and relationships between, these 3 species. Mexichromis antonii (Bertsch, 1976b), comb. nov. (Figures 3-I, 22 A, 23 - 25) Synonymy and Reference: Chromodoris antoni BERTSCcH, 1976b: 156-158; figs. 1-8 Material Examined and Distribution: 1) 1 specimen, Isla Alcatraz, Costa Rica (9°50’N; 84°53’ W); leg. A. J. Ferreira, February 1972 (identified from a color transparency) Vol. 21; No. 1 Type Locality: The type locality is Punta Aguja (near Mulege), Baja California. Mexichromis antonii also has been collected subtidally to 28m from Isla San Jose and Los Islotes in the Gulf of California, and in Santiago Bay, near Man- zanillo, Colima, Mexico. This new record extends the known range 2100km southeast. External Morphology and Coloration: Lengtlis of preserved specimens vary from 3 - 4.5mm; one specimen was 1omm long while actively crawling. Coloration consists of shades of blue, magenta, black, yellow-orange and white. A complete yellow-orange line encircles the rim of the notum; a black line immediately borders the entire inner side of the yellow-orange band. A wide area of light blue covers the rest of the lateral notal region. This zone is divided by a blackish line con- centric with the 2 outermost bands. The central dorsal region (from between the rhinophores to the anterior and lateral sides of the gills) bears a light magenta color, with darker splotches scattered randomly. Running lengthwise down the center of the notum is a thick, broken white / Zan 22-D 22-C. 22-E 22-F 22-G THE VELIGER Page 81 line, bordered by a slight yellowish tinge. Rhinophores are light magenta proximally, and black the distal 4 of their length. The 6 or 7 pinnate gill plumes are pinkish-white basally, each tipped with black. Rim of branchial pouch is tinged yellowish. The dorsal portion of the foot, ex- tending past the mantle, is rimmed by black, with succes- sive light blue and dark blue regions, with a small broken white line along its center. Radula: The approximate radular sizes and formulae of 3 spe- cimens are plotted in Figures 23 - 25. The combined rad- ular formula is approximately 54 - 78 (32 - 41° 0° 32 - 41). There are not enough specimens available to calculate regression line formulae. The radula has no rachidian tooth. The lateral teeth (Figure 22 A) bear long denticles, approximately 4 the total width of the erect hook along an antero-posterior plane. There is no prominent cusp thicker and larger than the succeeding denticles. Instead, this structure is reduced to approximately the same size and thickness as the den- ticles, and it is often actually shorter than the immediately adjacent denticle. The inner teeth of each half-row have 4 denticles. The innermost tooth does not appear to have additional denticles on its inner face. In the central por- tion of each half-row the teeth have 6-7 (sometimes 8) denticles. The outermost lateral teeth have only 4 or 5 denticles. All the teeth have a base not clearly set off from the erect denticular shaft; the postero-dorsal surface of the tooth curves evenly upwards from the posterior portion (< adjacent column) Figure 22 Mexichromis: radular teeth A - Mexichromis antonit: 3 lateral teeth (after BerTscH, 1976b) B -— Mexichromis porterae: HB 255 A; lateral tooth, LBM, 0.03 mm C — Mexichromis porterae: HB 255 B; lateral tooth, LBM, 0.024 mm D - Mexichromis porterae: HB 255 B; distal shaft of lateral tooth E - Mexichromis porterae: HB 390 A; 2™ lateral tooth, row 23, RSR; LBM, 0.026mm; length of base, 0.04 mm F — Mexichromis tura: USNM, F 809 (holotype); distal shaft, lateral tooth % the distance between center of radula and outer edge, approximately row 15 G - Mexichromis tura: USNM, F 809; outermost tooth, approx- imately row 7 Page 82 ou ° Maximum number of teeth/halfrow Number of rows Figure 23 Relation between maximum number of teeth per halfrow and number of tooth rows, Mexichromis porterae (dots), Mexichromis antonii (open circles) and Mexichromis tura (open triangles) of the base; outer teeth have a very short base. Scanning electron micrographs of the radula appear in BerTscu (1976b: figs. 3 - 8). Discussion: BeRTSCH (1976b) gives diagnostic separations of this rare species from other American Pacific Chromodoridi- nae, Mexichromis porterae (Cockerell, 1901), comb. nov. (Figures 3-J, 22 B-E, 23 - 25, 55 - 56) References and Synonymy: Chromodoris porterae COCKERELL, 1901: 79. COCKERELL, 1902: 20. MAcFaRLAND,1905: 44-45. MacFarvanp, 1906: 129; plt. 26, figs. 13-14. GuERNSEY, 1912: 74 to 75; fig. 39 B. JoHNson & SNooK, 1927: 494. MacFarranp, 1966: 163-165; plt. 24, figs. 4-5; plt. 34, figs. 24-31. BERTSCH & FERREIRA, 1974: 344. SmitH & CaRLTON, 1975: 528-529, 538. Bertscu, 1976b: 158. Glossodoris porterae (Cockerell). O’DonocHug, 1926: 212. O’DonocHuE, 1927: 91-92. SmirH & Gorpon, 1948: 180. Pruvot-For, 1951b: 134. Lance, 1961: 66. STEINBERG, 1963: 70. SPHON « Lance, 1968: 79. Ricketts & Carvin, 1968: 119, 514. ABBOTT, 1974: 355; pit. 17, fig. 4252. Hypselodoris porterae (Cockerell). Rotter & Lona, 1969: 425, 429. Lance, 1969: 37. ROLLER, 19704: 371. SPHON, 1972b: 65. Bertscu et al., 1973: 287. THE VELIGER Vol. 21; No. 1 Material Examined and Distribution: California: 1) 1 specimen, Pacific Grove; leg. F M. MacFarland, no date (HB 440; CAS) 2) 2 specimens, subtidal, Santa Cruz Island; leg. A. J. Ferreira, 11 July 1975 (HB 362 A-B) 3) 2 specimens, 12m subtidal, La Jolla kelp beds; leg. J. H. McLean, 9 September 1972 (HB 389 A-B; LA CM 72-110) 4) 2 specimens 21 - 24m subtidal, Isla Coronado; leg. A. J. Ferreira, 28 September 1973 (HB 255 A-B) Baja California, Mexico: 5) 3 specimens, subtidal, Sacramento Reef, S of Isla Geronimo (29°48’N; 115°48’W); leg. A. J. Ferreira, 26 September 1973 (HB 254 A-C) 6) 1 specimen, 6-12m subtidal, Sacramento Reef; leg. J. H. McLean, 26-27 September 1971 7) 3 specimens, 24m subtidal, SW of Isla Natividad, ap- proximately 2okm S of Isla Cedros (27°52’N; 115° 12/40” W) ; leg. J. H. McLean and P. LaFollette, 22 Oc- tober 1971 (HB 390 A-C; LACM 71-165) 1 specimen, Baja California; R/V Searcher, 1971 (HB 391; LACM A 8500) = Type Locality: The type locality of Mexichromis porterae is La Jolla, California; the range of the species is from Monterey, California, to the vicinity of Isla Cedros, Baja California (lot 7, from SW of Isla Natividad, is the southernmost known record). Intermediate collecting records are Santa Barbara County (SPHON & Lance, 1968), Laguna Beach (GuERNSEY, 1912), and San Diego (MacFar.anp, 1966). External Morphology and Coloration: Length of living specimens is usually 10 - 20mm (largest, 28.2mm; MacFartanb, 1966: 165). Body color is a deep ultramarine blue (illustrated in MAcFaRLAND, 1966, and Lance, 1969). Dorsum has 2 longitudinal bright orange (or yellow) stripes that end anteriorly at the rhinophores, and a single bright orange (or yellow) crescent-shaped stripe anterior to the rhinophores. A median light blue line extends from between the rhinophores to the anterior edge of the branchial pocket; mantle margin is rimmed with a narrow white band. There are approximately 9 to 12 branchial plumes; rhinophores and gills are bluish, lighter basally than distally. Radula: There is only one, incomplete, description of a Mezxi- chromis porterae radula in the literature (MaAcFARLAND, Vol. 21; No. 1 1966: 164). The data from 1o radulae are presented in Table 11. The combined radular formula is 38 - 68 (23 - THE VELIGER Table 11 Radular variation in Mexichromis porterae Maximum number Specimen Width: Number of teeth (HB Length Width length — of tooth per numbers) (inmm) (in mm) ratio rows half-row 254B 0.848 0.299 1:2.84 51 25 254C 0.558 0.162 1:3.44 4] 23 262 A 0.654 0.234 1:2.79 38 24 262 B 0.856 0.267 13 =a 49 27 389 A 0.865 0.283 1:3.06 50 30 389 B 0.808 0.283 1:2.86 49 29 390 A 1.333 0.695 1:1.92 52 36 390 B 1.27 0.63 1:2.02 68 35 391 A 0.913 0.533 1:1.71 51 34 391 B 0.824 0.259 1:3.18 42 32 x 0.893 0.365 1:2.703 49.1 29.5 s 0.2407 0.1839 0.603 8.25 4.696 360: 23 - 36); there is no rachidian tooth (agreeing with MacFar.anp’s, loc. cit., statement, “As clearly as can be made out there is no median plate”’). Because of both thesmall number of available specimens that I examined, and the range of variation, no correlation was statistically proven between the number of tooth rows and the maximum number of teeth per halfrow (r= 0.629, P<0.1 > 0.05). The data are plotted in Figure 23. A positive correlation was proven between the length of the radula and the number of tooth rows (Figure 24). The regression line formula is Y = 24.8+4+27.22 X; r= 0.7939, P < 0.01, n= 1I0. Similarly, a positive correlation exists between the width of the radula and the maximum number of teeth per half- row (Figure 25). The equation is Y = 21.51+21.93 X; the coefficient of correlation is 0.8588 (P < 0.01, n= 10). The radula and its teeth are extremely small. The mor- phology of innermost lateral teeth (Figures 55-56) ap- proaches a Hypselodoris-shape, but the first 2 denticles are not developed as much, and the first denticle is not the large, dominant cusp of Hypselodoris. Lateral teeth (Fig- ures 22 B - E) vary in shape. The distal shaft ends consist- ently with a pointed denticle smaller than or equal in size to the succeeding denticles. This unique generic character- Page 83 istic is exceptionally well illustrated by MACFarLANp, (1966: plt. 34, figs. 24, 25, 27, and 28), who also wrote (op. cit.: 164) that “the teeth are lamellate, bifid at the summits, their bases long, much compressed, hooks den- 7° 2 Number of rows on ° 40 30 0.5 1.0 1.5 Length of radula (mm) Figure 24 Correlation between number of tooth rows and length of radula, Mexichromis porterae (calculated regression line), Mexichromis antonu, and Mexichromis tura. Symbols as in Figure 23 Maximum number of teeth/halfrow 0.25 0.5 0.75 Width of radula (mm) Figure 25 Relation between maximum number of teeth per half-row and width of radula, Mexichromis porterae (calculated regression line), Mexichromis antonti,and Mexichromis tura. Symbols as in Figure 23 Page 84 ticulate, six to seven long denticles on the outer ones.” The distal points on the teeth shafts are not bicuspid (in the sense defined by BertTscH, 1977), but show the acusp- id shape diagnostic of species belonging to Mexichromis. Discussion: Mexichromis porterae was named after Wilmatte Porter Cockerell. It is a distinctive species, still rarely reported even though its original description was over 75 years ago. It appears to be more common subtidally than inter- tidally; only one of the 10 specimens I examined was col- lected intertidally, and its known distribution in Santa Barbara County is limited to “subtidal to 60 feet” [18m] (SPHON & LANCE, 1968: 79). Mexichromis tura (Marcus & Marcus, 1967), comb. nov. (Figures 3-K, 22 F - G, 23 - 25, 61 - 64) References and Synonymy: Chromodoris tura Marcus & Marcus, 1967: 55 - 56; 53, figs. 59-61; pit. 1, fig. 3. Keen, 1971: 822. SPHON, 1972b: 59. BeERTscH et al., 1973: 292, 293. KEEN & COAN, 1975: 43 Glossodoris tura (Marcus & Marcus). ABBOTT, 1974: 355; fig. 4244 Thorunna tura (Marcus & Marcus). BertscH & FERREIRA, 1974: 344-345. BertscH, 1976b: 158 Material Examined and Distribution: 1) 1 specimen, La Paz area; leg. E. Janss, Jr., April 1974 (HB 435; LACM) 2) 3 specimens, intertidal, La Cruz, Nayarit, Mexico; leg. F « R. Poorman, 3 January 1976 (HB 418 A-C; LA CM A 8477) This species is very rare. It has been reported from one specimen collected at Deale Beach (Fort Kobbe Beach), Panama (type locality) and 4 specimens collected at Sayulita, Nayarit. The new material adds the southern THE VELIGER Vol. 21; No. 1 Gulf of California to its range. The species has a disjunct known distribution from 3 widely scattered localities in the Panamic province. External Morphology and Coloration: Center of dorsum is dark violet to nearly black, with reddish spots and dashes scattered throughout, and yel- lowish streaks around its border (Marcus & Marcus, 1967: plt. 1, fig. 3). Notum is surrounded by a broad bluish-white margin within which is a complete orange band around the animal. Foot dark violet with an orange midline on the dorso-posterior surface. The animal col- lected by E. Janss had yellow markings instead of the red or orange markings of the holotype. Radula: Meristic characters of the radula are in Table 12 and plotted in Figures 23 - 25. The 3 known radulae have 42 to 67 rows of teeth. No rachidian tooth. The lateral teeth (Figures 61 - 64) have an acuspid shape throughout the majority of the tooth rows. Additional drawings of the holotype’s radular teeth (USNM 576266, F 809) are presented in Figure 22 F -G. Table 12 Radular variation in Mexichromis tura Maximum number Specimen Width: Number of teeth (HB Length Width length — of tooth per numbers) (inmm) (in mm) ratio rows half-row 6 — — a 42 31 418 C 0.921 0.372 1:2.48 67 — 435 0.703 0.404 1:1.74 57 4) 6Marcus & Marcus, 1967. Explanation of Figures 57 to 62 Scanning Electron Micrographs of the Radular Teeth of Mexichromis tura and Hypselodoris californiensis Figure 57: Mexichromis tura; inner lateral teeth (HB 418 C) X800 Figure 58: Mexichromis tura; innermost lateral teeth (enlargement of Figure 57) (HB 418 C) 2400 Figure 59: Mexichromis tura; teeth from middle of half-row (HB 418 C) X80o Figure 60: Mexichromis tura; lateral teeth (HB 418B) X800 Figure 61: Hypselodoris californiensis; overall view of several tooth rows (HB 252 B) X200 Figure 62: Hypselodoris californiensis; outermost lateral teeth (HB 252 B) X675 THE VELIGER, Vol. 21, No. 1 [BerTSCH] Figures 57 to 62 Figure 60 Y Wy TOY Wa Wi, y Ny 9 ‘ My N) pip i, i a Lg Figure 61 Figure 62 a Vol. 21; No. 1 Discussion: Examination of additional specimens has resulted in the re-evaluation of the generic placement of this species. In the original description, Marcus & Marcus (1967: 56) wrote, “The length of the first denticle behind the cusp makes the decision between Chromodoris and Hyp- selodoris difficult. One or two innermost teeth are not sufficient to define such a species generically. In Chromo- doris most teeth are unicuspidate, hook-shaped and ser- rate on the outer side; in Hypselodoris most are bicuspi- date or bifid.” Placement of the species into Mexichromis more clearly differentiates between the Chromodoridinae. A glance at the scanning electron micrographs shows that the majority of teeth of M. tura are acuspidate. Such a total impression is biologically meaningful, since the mor- phological trait is present throughout an entire multi- structural functioning unit. BerTSCH & FERREIRA (1974: 344-345) transferred this species to the genus Thorunna Bergh, 1877. This is inadequate, because even though the innermost lateral tooth is twice as broad as the following tooth, the gestalt pattern of Thorunna first lateral teeth is highly different from that of Mexichromis tura. Figures 57 and 58 of this work and fig. 61 of Marcus « Marcus (1967: 52) show an innermost tooth with a broad base (but with a greater basal length), that does not appreciably increase in width posteriorly. The 1* lateral tooth of Thorunna widens posteriorly, so that its greatest breadth at least equals the length of the tooth’s base; and its base approaches a chevron-shape (cf. BercH, 1878a: plt. 63, fig. 18; RisBEc, 1928: figs. 48 - 50; Basa, 1949: figs. 61 - 63; Burn, 1966: figs. 6 and 8; Er. Marcus « Ev. Marcus, 1970: fig. 21). This shape does not occur in Mexichromis tura. Discussion of Mexichromis The distinctive radular morphology is probably indicative of a trophic specialization among the members of this genus. Although the members of the Chromodoridinae are rasping sponge feeders (cf., for instance, YOUNG, 1970), sharing basic radular structural similarities, there are a variety of teeth shapes that characterize each of the major generic evolutionary lineages within the subfamily. Detailed laboratory and field studies are needed to cor- relate feeding specificity with the different radular tooth patterns, similar to studies done on broader samplings of different opisthobranch taxa (BERTSCH, 1974; BLooM, 1976). THE VELIGER Page 85 Literature Cited Aspott, Ropzrt Tucker 1974. American seashells. Van Nostrand Reinhold Co., New York, 2nd ed.; 663 pp.; 24 color plts.; numerous figs. Baza, KrxuTar6 1949. Opisthobranchia of Sagami Bay, collected by his Majesty the Emperor of Japan. Iwanami Shoten, Tokyo: 4+2+194+7 pp.; 50 plts.; 161 text figs. (September 1949) Bgrou, Lupwic SopHus RuDOLF 1877. Malacologische Untersuchungen. In: C. Semper, Reisen im Archipel der Philippinen 2 (12): 495 - 546; plts. 58-61 (15 Dec. ’77) 1878a. Malacologische Untersuchungen. In: C. Semper, Reisen im Archipel der Philippinen 2 (13): 547-601; plts. 62-65 (8 July ’78) 1878c. Untersuchungen der Chromodoris elegans und villafranca. Malakol. Blatter 25: 1 - 36; 2 plts. 1879a. Neue Nacktschnecken der Siidsee, malacologische Untersuchun- gen, IV. Journ. Mus. Godeffroy 5 (14): 1-50; plts. 1-5 (28 February 1879) 1879c. On the nudibranchiate gasteropod Mollusca of the North Pacific Ocean, with special reference to those of Alaska, prt. 1. Proc. Acad. Nat. Sci. Philadelphia, 31: 71 - 132; plts. 1-8 (10 May 1879) (the exact dates of publication of Bercu’s 1879 articles fide Burn, 1978) 1880. On the nudibranchiate gasteropod Mollusca of the North Pacific Ocean, with special reference to those of Alaska. Part II. Proc. Acad. Nat. Sci. Philadelphia 32: 40 - 127; plts. g- 16 (March-June 1880) 1890a. Report on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78), and in the Carib- bean Sea (1879-80), by the U.S.Coast Survey Steamer “Blake,” Lieut.-Commander C. D. Sigsbee, U.S. N., and Commander J. R. Bart- lett, U.S.N., commanding. XXXII. Report on the nudibranchs. Bull. Mus. Comp. Zoology Harvard 19 (3): 155 - 181; 3 plts. (March 1890) 1891. Die cryptobranchiaten Dorididen. Zool. Jahrb., Abt. Syst. 6 (1): 103 - 144 (20 October 1891) 1892. System der nudibranchiaten Gastropoden. In: C. Semper, Reisen im Archipel der Philippinen, Wissenschaftliche Resultate 2 (18): 995 to 1168 (pagination 1-173 also occurs) (22 July 1892) 1898. Die Opisthobranchier der Sammlung Plate. Zool. Jehrb. (Suppl.) 4 (3): 481-582; plts. 28 - 33 (15 December 1898) Bertscu, Hans 1970. Opisthobranchs from Isla San Francisco, Gulf of California, with the description of a new species. Contrib. Sci., Santa Barbara Mus. Nat. Hist 2: 1-16; 13 text figs. (1 December 1970) 1971. Natural history and occurrence of opisthobranchs of Las Cruces, Baja California, Mexico, and vicinity. The Echo (Abstr. & Proc. 3rd Ann. Meetg. West. Soc. Malacol.) 3: 16 (7 Marck 1971) 1973. Distribution and natural history of opisthobranch gastropods from Las Cruces, Baja California del Sur, Mexico. The Veliger 16 (1): 105-111; 2 maps (1 July 1973) 1974. Nudibranch radular morphology and prey specificity. West. Soc. Malacol. Ann. Reprt. 7: 33 (12 November 1974) 1976a. Intraspecific and ontogenetic radular variation in opisthobranch systematics (Mollusca: Gastropoda). System. Zool. 25 (2): 117-122 7 text figs. (9 July 1976) 1976b. A new species of Chromodorts (Opisthobranchia : Nudibran- chia) from tropical west America. The Veliger 19 (2): 156-158; 1 plt.; 2 text figs. (1 October 1976) 1977. The Chromodoridinae nudibranchs from the Pacific coast of America. Part I. Investigative methods, and supra-specific taxonomy. The Veliger 20 (2): 107-118; 3 text figs. (1 October 1977) 1978. The Chromodoridinae nudibranchs from the Pacific coast of America. Part II. The genus Chromodoris. The Veliger 20 (4): 307 - 3275 3 pits.; text figs. 4-15 (1 April 1978) BrrtscH, Hans & ANTONIO J. FERREIRA 1974. Four new species of nudibranchs from tropical west America. The Veliger 16 (4): 343-353; 7 plts. (1 April 1974) Bertsos, Hans, ANTONIO J. Fernzma, Wesiry M. Farmer e THOMAS L. Haves 1973. | The genera Chromodosis and Felimida (Nudibranchia : Chromo- dorididae) in tropical west America: distributional data, description of a new species, and scanning electron microscopic studies of radulae. The Veliger 15 (4): 287 - 294; 5 plts.; 3 text figs. (1 April 1973) Bertscu, Hans « KaniAutono B. MEYER ae In prep. Opisthobranchs of the Pacific coast of Panama, with additional data on some Californian and Atlantic species. Page 86 BIRKELAND, CHartes, Davi L. Meyer, James P Stames & Caryn L. Burorp 1975. Subtidal communities on Malpelo Island. in: Jeffrey G. Graham (ed.), The biological investigation of Malpelo Island, Colombia. Smithson. Contrib. to Zool. 176: 55 - 68; figs. 20 - 27 Broom, STEPHEN A. 1976. Morphological correlations between dorid nudibranch preda- tors and sponge prey. The Veliger 18 (3): 289-301; 1 text fig. (1 January 1976) Brusca, RicHarp C. 1973. A handbook of the common intertidal invertebrates of the Gulf of California. Univ. Arizona Press, Tucson, Ariz. xi+427 pp.; 1 map; 273 text figs. Burn, Rosert 1966. On three new Chromodoridinae from Australia (Opisthobran- chia : Nudibranchia). The Veliger 8 (3): 191-197; 8 text figs. (1 January 1966) 1978. Publication dates of Bergh’s 1879 papers describing American chromodorids. The Veliger 20 (3): 298-299 (1 January 1978) Cockerz.L, THzopore Dru ALIson 1901. Pigments of nudibranchiate Mollusca. Nature 65 (1674): 79 - 80 (28 November 1901) 1902. Three new species of Chromodoris. The Nautilus 16 (2): 19-21 (June 1902) 1908. Mollusca of La Jolla, California. The Nautilus 21 (9): 106 - 107 (3 January 1908) CockrrELL, THEOpoRE Dru ALIsoNn « CHartzes ELIoT 1905. Notes on a collection of Californian nudibranchs. Journ. Malacol. 12 (3): 31-53; plts. 7, 8 (29 September 1905) Euzrson, Wittiam Keita & Morris KARLMANN JACOBSON 1976. The American Museum of Natural History guide to shells, land, freshwater, and marine, from Nova Scotia to Florida. vii+ 482+ Xviii pp.; 47 plts.; text figs. Alfred A. Knopf, Inc., New York Farmer, WEsLey 1963. | Two new opisthobranch mollusks from Baja California. Trans. San Diego Soc. Nat. Hist. 18 (6): 81-84; 1 plt.; 1 text fig. (27 September 1963) 1967. Notes on the Opisthobranchia of Baja California, Mexico, with range extensions. — II. The Veliger 9 (3): 340-342; 1 text fig. (1 January 1967) Guransty, MABEL 1912. Some of the Mollusca of Laguna Beach. Marine Lab. 1: 68-82; figs. 32 - 43 Jouneon, Myrtie Exanera & Harry James SNOOK 1927. Seashore Animals of the Pacific Coast. Macmillan, New York: 659 pp. Kay, EvizaseTH Auison & Davi K. Youno 1969. The Doridacea (Opisthobranchia: Mollusca) of the Hawaiian Islands. Pacif. Sci. 2g (2): 172 - 231; 82 text figs. (30 April 1969) Kezn, A. Myna 1971. Sea shells of tropical West America: marine mollusks from Baja California to Peru. Stanford Univ. Press, Stanford, Calif. i - xiv+ 1066 pp.; ca. 4000 figs.; 22 color plts. (1 September 1971) Keen, A. Myra « Evozng Victor Coan 1975. “Sea shells of tropical West America”: Additions and corrections to 1975. Western Soc. Malacol. Occ. Pap. 1: 66 pp. (22 June 1975) Lancg, James Ropert 1961. A distributional list of southern California opisthobranchs. The Veliger 4 (2): 64-69 (1 October 1961) 1968. | New Panamic nudibranchs (Gastropoda; Opisthobranchia) from the Gulf of California. Trans. San Diego Soc. Nat. Hist. 15 (2): 13 pp.; 2 pits.; 11 text figs. (8 January 1968) 1969. Portraits of California’s colorfvl sea slugs. Oceans 1 (5): 33-37; 11 text figs. (June 1969) MaoFarcanp, Frank Mace 1905. A preliminary account of the Dorididae of Monterey Bay, Cali- fornia. Proc. Biol, Soc. Wash. 18: 35 - 54 (2 February 1905) 1906. | Opisthobranchiate Mollusca from Monterey Bay, California, and vicinity. Bull. U.S. Bur. Fish. (1905) 25: 109-151; plts. 18-31 (24 May 1906) 1966. Studies of opisthobranchiate mollusks of the Pacific coast of North America. Mem. Calif. Acad. Sci. 6: xvi+546 pp.; 72 pits. (8 April 1966) Pomona Coll. Rept. (May 1912) THE VELIGER Vol. 21; No. 1 Mancus, Ernst « Eveune pu Bors-ReyMonp Marcus 1970a. Opisthobranch mollusks from the southern tropical Pacific. Pacif. Sci. 24 (2): 155-1793 54 text figs. (15 April 1970) Marcus, Eve.ine pu Bois-Reymonp & Ernst Marcus 1967. American opisthobranch mollusks. Studies in tropical oceano- graphy (Univ. Miami Inst. Marine Sci., Miami, Florida), no. 6: viii-+ 256 pp.; figs. 1-155 + 1-95 (22 December 1967) Mayr, Ernst 1969. Principles of systematic zoology. xi+428 pp.; illust. O’DonocHvz, Cartes Henry 1926. A list of nudibranchiate Mollusca recorded from the Pacific coast of North America with notes on their distribution. Trans. Roy. Canad. Inst. 15 (2): 199 - 247 1927. Notes on a collection of nudibranchs from Laguna Beach, Cali- fornia. Pomona Journ. Entom. Zool. 19 (1-4): 77-119; plts. 1-3 Pruvot-For, ALice New York (McGraw-Hill) 1951a. Revision du genre Glossodoris Ehrenberg. Journ. de Con- chyl. 91 (3): 76 - 132 (July 1951) 1951b. Revision du genre Glossodoris Ehrenberg. Journ. de Con- chyl. 91 (4): 133 - 164 (October 1951) Ricketts, Epwarp F « Jack Catvin 1968. Between Pacific tides. 4th ed. Revised by Joel W. Hedgpeth. xiv+614 pp.; illus. Stanford Univ. Press, Stanford, Calif. RusBEc, J. 1928. Contribution a I’étude des nudibranches Néo-Calédoniens. Faune colon. frang. 2 (1): 1-328; pits. A-D and 1-12; 98 text figs. Roxzrer, Ricnarp A. 1970a. A list of recommended nomenclatural changes for MacFarland’s “Studies of opisthobranchiate mollusks of the Pacific coast of North America.” The Veliger 12 (3): 371-374 (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) Rotizr, Ricwarp A. and STEVEN J. Lonc 1969. Am annotated list of opisthobranchs from San Luis Obispo County, California. The Veliger 11 (4): 424-430 (1 April 1969) Skoc.tunp, Caror 1970. An annotated bibliography of references to marine Mollusca of the northern state of Sonora, Mexico. The Veliger 12 (4): 427-492 . (1 April 1974) Suara, ALLyN Goopwin e MacKenzie Gorpon, Jr. 1948. | The marine mollusks and brachiopods of Monterey Bay, Califor- nia, and vicinity. Proc. Calif. Acad. Sci. (4) 26 (8): 147-245; pits. 3, 4; 4 text figs. (15 December 1948) Sxrrn, Ratpo Incram @ James T. Carton, eds. 1975. Light’s Manual: Intertidal invertebrates of the central Cali- fornia coast. Third edition, xviiit+716 pp.; 156 plts. Univ. Calif Press, Berkeley, Calif. (8 May 1975) SpHon, Gare G. 1972a. Psychedelic slugs. Terra 11 (1): 1,3-6 (Summer 1972) 1972b. An annotated checklist of the nudibranchs and their allies from the west coast of North America. Opisthobranch Newsletter 4 (10-11): 53-79 (October - November 1972) SpHon, Garg G. « James Rospert Lance 1968. An annotated list of nudibranchs and their allies from Santa Barbara County, California. Proc. Calif. Acad. Sci. (4) 36 (5): 73 - 84; 1 text fig. (25 September 1968) SpHon, Gare G. « Davm K. MuLLiner 1972. A preliminary list of known opisthobranchs from the Galépagos Islands collected by the Ameripagos Expedition. The Veliger 15 (2): 147 - 152; 1 map (1 October 1972) StTeinzerc, Joan Emiy 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) Youno, Davw KenneTH ; 1970. The functional morphology of the feeding apparatus of some Indo-West-Pacific dorid nudibranchs. Malacologia 9 (2): 421 - 446; 17 text figs. (20 July 1970) Vol. 21; No. 1 THE VELIGER Page 87 Reviews of Biology of Commercially Important Squids in Japanese and Adjacent Waters I. Symplectoteuthis oualantensis (Lesson) TAKASHI OKUTANI anp IH-HSIU TUNG Tokai Regional Fisheries Research Laboratory, Tokyo and National Taiwan University, Taipei (7 Text figures) Symplectoteuthis oualaniensis*, an oceanic squid of the family Ommastrephidae, is distributed in the vast warm waters in the Indo-Pacific region, but it has been commer- cially utilized only in Okinawa (Japan) and Taiwan (Re- public of China). This species frequently has been en- countered in such large numbers during oceanographic observations along warm water Japanese coasts (ITAKURA, 1977) that a large stock exists for fisheries exploitation. A report of the R/V Shoyo-Maru Expedition to the Gulf of Arabia described the existence of a large school of S. oualaniensis from the waters off Karachi, Pakistan (docu- ment from Far Seas Fisheries Research Laboratory, 1976). In spite of the economic importance of this squid, very little information on biology and fisheries is available. CiarKE (1966), Younc (1975) and WormuTH (1976) briefly reviewed the biology of this species, while TUNG et al. (1973), Tune (1975, 1976a, 1976b), Ryukyu Fish- eries Experimental Station (1971) and Okinawa Prefec- tural Fisheries Experiment Station (1972) contributed a great deal of fishery-biological information of this inter- esting squid in the Northwest Pacific. This paper reviews chiefly these recent Chinese and Japanese contributions. ACKNOWLEDGMENT This review was read by Dr. Clyde F E. Roper, Smith- sonian Institution, Washington, D. C. We owe thanks to * English version of the proceedings of the symposium on the cur- rent status of cephalopod fishery in the waters around Japan, held at Niigata, Japan, 10-11 March 1977 2 Zuev et al. (1975) incorrectly applied the generic name Stheno- teuthis him for his criticism and kind correction of English gram- mar. IDENTITY Symplectoteuthis oualaniensis (Lesson, 1830) is a species of relatively large animals among the family Omma- strephidae. The largest specimen reported by CLARKE (1966) was 30.5cm ML (female), but individuals of this species grow much larger. Two females from the Indian Ocean measured 41cm and 46cm, respectively (Okutani, unpubl. ). This species is similar to the partly sympatric Omma- strephes bartrami (Lesueur, 1821) at a glance, but is easily distinguished from it by its fused mantle-funnel con- nective (on one or both sides) and an oval patch of photo- phores on the antero-dorsal surface of the mantle. CLARKE (1965, 1966) noted the existence of a smaller form within the S. oualaniensis population that has no photophores. Younc (1975) stated that the form with photophores will be considered to be true S. oualaniensis, not only for convenience’s sake, but also because of its far more fre- quent occurrence. WorMUTH (1976) took the same view as Young and considered that the 2 forms likely are distinct species. DISTRIBUTION Rhynchoteuthion larvae of Symplectoteuthis oualaniensts may be contained among those reported as “S. oualanien- sis-type larvae” by OkuTANI (1964), OKUTANI & McGow- AN (1969), SHojimMA (1969) and YAMAMOTO & OKUTANI Page 88 (1976). The “S. oualaniensis-type larvae” are character- ized by: (1) along “proboscis” (fused tentacles), (2) fewer mantle chromatophores than in Todarodes pacificus larvae, (3) smaller size in comparison to the equivalent stage of T: pacificus (1. e., the tentacles separate at a stage smaller than 7mm ML), and (4) a pronounced intestinal photophore (CLARKE, 1966; Nesis, personal Figure 1 Rhynchoteuthion of Symplectoteuthis oualaniensis A: After CrarKe (1966) B: After Nests (unpublished) communication) (Figure 1). A large number of this rhynchoteuthion is distributed in the surface waters around Japan and ‘Taiwan, but separation of true S. oua- laniensis rhynchoteuthion from larvae of other sympatric ommastrephid species has not always been well estab- lished. Rhynchoteuthion larvae of S. oualaniensts may oc- cur in summer in more offshore waters where those of T. pacificus are seldom distributed then. At a juvenile stage of ML 5-6cm, S. oualaniensis is easily distinguished by the very pronounced intestinal photophore and the mantle-funnel fusion (the latter characteristic is not dis- tinct in early larvae the integument of which is still very delicate). Juveniles frequently are aggregated in inshore waters of oceanic islands. According to the observations of one of us (T. O.), such aggregations of juveniles were found at Hachijo Island and Ogasawara (Bonin) Islands. Juveniles dip-netted near the Seychelles in the Indian O- cean (OKUTANI, 1970) and from Guadalupe Island, Mexico (Invertebrate Collection in the Scripps Institu- tion of Oceanography) were also examined. YouNnc (1975) also recognized the abundance of juveniles in some insular areas by the evidence from birds’ stomach con- tents. On the basis of an observation on behavior of a dip-netted juvenile that adhered to the bottom of a con- THE VELIGER Vol. 21; No. 1 tainer, Okinawa PFES (1972) assumed that the animal may crawl on the bottom in its natural environment. It is difficult to believe that this assumption was correct, as such behavior was most unlikely a normal posture. Symplectoteuthis oualaniensis is known to be abundant- ly distributed in the surface waters both day and night, as it frequently js jigged or dip-netted at the surface and also is seen “flying” over the sea surface (ITAKURA, 1977). No direct evidence on vertical distribution of this species has been available. Younc (1975) inferred that this spe- cies may have a vertical distribution similar to that of the related genus, Ommastrephes, that is known to occur from the surface to depths of 1500 m. The major fishing grounds are located on the south- western coasts of Taiwan (TuNc, 1976a) and beyond the 200 m-contour off the Ryukyu chain (Ryukyu FES, 1971) (Figure 2). The fishing season near Taiwan is from March to November with the peak in May - August. Fishing is most productive at water temperatures above 26° C and particularly around 28°C. In the Ryukyu waters, the fishing season lasts from May to October at Yaeyama Region and from June to November at Okinawa Region. The surface water temperature for the season varies from 22°C to 28° C. The coastward shift of the 27° C-iso- therm corresponds well to the location of the fishing grounds (Ryukyu FES, 1971). The landings of Symplecto- teuthis oualaniensis at 2 major fishing ports in Taiwan and one in Okinawa are shown in Table 1. At 29° N, 135° E, this squid is continuously seen from May to October, particularly frequent at above 23° C in surface temper- ature at the station (ITAKURA, 1977). Table 1 Landing of Symplectoteuthis oualaniensis in Taiwan (Kaohsiung and Henchun) and in Okinawa (Itoman) (Tune et al. 1973; Ryuku Fisheries Experimental Station 1971). Unit: Kg Taiwan Okinawa Year Kaohsiung Hengchun Itoman 1966 2 4 42014 1967 ‘ 47659 1968 4 3 41501 1969 : 4 29907 1970 149556 6414 49166 197] 106566 3837 “ 1972 28219 1181 4 4No published data are available. Vol. 21; No. 1 THE VELIGER Page 89 EAST CHINA SEA Straits NORTHWEST PACIFIC 120° E 130° E Figure 2 Index Map for Okinawa - Taiwan Area Page 90 GROWTH Tunc et al. (1973) recognized 2 size groups® in May: 12-18cm ML and 19-24cm ML. The smaller group grew to 16 - 22cm in mid- to late June, while the larger group vanished from the fishing ground. Simultaneously another school with a mode at 12 - 13cm ML entered the area and similar small-sized groups are recruited continu- ously until early September. Recruits grew as big as 16 to 17cm by November (Figure 3). Therefore, the squid eTows 4cm in 2 months (from early May till early July and from early September till early November). Such a re- cruitment of smaller size groups has also been apparent in the sea around Okinawa (Ryukyu FES 1971 and Okina- wa PFES 1972). The relation between ML and body weight (BW) given by Tunc e¢ al. (1973) is: log BW = 2.8481 log ML — 4.0088. According to the most recent study by Nesis (1977), the population of Symplectoteuthis oualantensis in the western tropical Pacific is composed of 2 different groups, namely, a small and early-maturing group (EM) and a large and late-maturing group (LM). The EM matures at 1ocm ML in males and 13cm ML in females with a life span of about 8 - g months, while the LM matures at 12-13cm ML in males and 20- 24cm ML in females with a life span slightly longer than one year. The EM is distributed only in the central part (between 55° E and 175°W, and 10° - 15° N and S) of the whole range of the species. The EM differs from the LM in the absence of the dorsal photophore patch, which is differentiated in the LM at about 10cm ML. Nesis also mentions that sperma- tophore and heterocotylus are different from each other. This supports the view of CLarKE (1966) and WorMUTH (1976) that 2 forms within S. oualaniensis are different from each other not only in the presence (and absence) of the dorsal light organ but also in size at maturity, max- imum size, abundance and distributional range. Nesis thinks that these groups are genetically differentiated “superpopulations” within the species. REPRODUCTION The left arm IV is hectocotylized and is developed from about 11cm ML onward. Unlike that in Todarodes pacifi- cus, in which the distal half of the right arm IV is modi- fied into comb-like papillae mostly with suckers, the distal half (50.3 + 2.66%) of the hectocotylized arm completely 3 On photophore-bearing type only THE VELIGER Vol. 21; No. 1 lacks suckers and has a sharp fleshy ridge with smooth or undulated sides. The hectocotylized arm is slightly longer (114.9+5.8%) than the normal right arm IV. Date ° 5 SUL s5:19 ng ¢ LIL, 60.6.1 HU] of _ 60.8.25-26 Essar o4 ce, Jeocgneeg |) J 615.1513 JY ri 815-1424 915-2564 PHL 61-65-24 py Pe 616.2574 a siawe DY Pp capers (Ib Tn, 6186-22 lk | - 61.8.23-9-4 sR oo, 619515 anal 61.9.16-25 Ala ee 61.10.10-20 JL, AL ones M1 % 60.9.16 61.11.18 10 15 20 25 10 15 20 cm Figure 3 Seasonal Change of Mantle Length Composition (Tune et al., 1973) The years 6o and 61 correspond to 1971 and 1972 A. D. Vol. 21; No. 1 Concerning the sex ratio of this squid, Tune et al. (1973) and Tunc (1976a) found that the males comprise about 31% of the population in the early fishing season and 21% in the closing season (average 25%). The sex ratio is 1:1 at the stage of 10- 13cm ML, while males gradually diminish in numbers after 14cm ML. Females strongly predominate in the commercial catches in Okina- wa, comprising some 70 - 80% thereof (Okinawa PFES, 1972). This may coincide with the fact that males mature much earlier than females and disappear from the fishing grounds. Also, schools appear first in the north of Luzon with a high ratio of males and migrate northward along the Kuroshio Current, spreading to the southwest and east of Taiwan and then northward to the Ryukyu Region. Tune (1976a) observed copulating behavior at 0300 on June 28, 1973, at surface at 21°06’N; 120°58’E, north of Luzon. The observed pair was a male about 13cm and a female about 20cm. The female which had been swim- ming about 20cm ahead of the male suddenly changed its orientation and grasped the male in a head-to-head posi- tion. The male then changed its position to form an angle of 45° with the female, but soon returned to the linear head-to-head position while sinking out of sight. Among 37 males captured at that time, 35 carried sper- matophores and among 136 females, 72 were impregnated with spermbulbs. This species does not seem to eject all spermbulbs at one copulation but may copulate with several females. Artificial fertilization experiments were made on board the ship at the same time. Among 3 trials, the most successful one had a fertilized egg develop until blastopore formation and differentiation of the eyes. The asymmetrical ripe eggs are translocated to the oviduct when the ova are 0.75mm in major diameter. The number of ova rapidly increases since at 15cm ML, 5g of ovary contain 10 000 to 20 000 eggs. The relation be- tween ovary weight (W,,) and MLis: W.v = 4.18 ML - 65.34 The largest ovary ever measured was 58.4 g and contained 250000 eggs. Eggs in the oviduct measure 0.788+0.03mm (0.714 — 0.872mm) in major diameter. The minor diameter is about 84.5441.95% (80.03 - 87.86%) of the major dia- meter. The maximum weight of the oviduct is about 40% of the entire female reproductive system. The eggs in the oviduct attained a maximum weight of 33.1g, in which there were 123 562 eggs present. Nidamental glands are as small as 2cm in squid of 15- 16cm ML but grow to 7cm at 18- 19cm ML. The relation between the length of the nidamental gland (Ln) and mantle length shows a logarithmic curve in which the point of inflexion is present at 17.2cm ML or 4.7¢cm in THE VELIGER Page 91 30 40 GLI=50 ML vi cm 25 yy 20 10 ce) Figure 4 GLI = (Ln/ML X 10? (Tune, 1976a) Ln (Figure 4). The relation between weight (Wn) and length of the nidamental gland is: Wn = 0.070924 Ln*5**, The relations among various measurements in the male reproductive system and ML are shown in Table 2 (Tune, 1976a). The spermbulbs are implanted around the female’s mouth. Close examination of 10 females showed 15.2 spermbulbs implanted on the ventral side of the inner lip of the buccal mass, 6.1 on the dorsal side, 0.2 on the outer lip, 0.3 on the inner surface of the buccal membrane, 1.4 in the outer region of the same, and 0.6 on other places, suchas the base of the arms. Thespermbulbs planted usually are covered by a gelatinous covering and are embedded in the soft tissues of the lips for 4-3 of the length of the bulbs. All of the females larger than 24cm ML are implanted with spermbulbs, ranging from 1 to 83 bulbs (Figure 5). The seminal receptacle usually is composed of 2 vesicles, but occasionally of 5 - 6. They are unevenly distributed around the buccal membrane and vary from 9 to 163 in number. The seminal receptacles are usually undeveloped in females smaller than 13cm ML. The ratio of specimens having receptacles exceeds 50% at 15cm ML and reaches 100% at 18cm ML. Page 92 THE VELIGER Vol. 21; No. 1 Table 2 Relation between measurements in male genital organ and ML (Tune 1976 a). Entry Corr. Coef. Regression formulae Testis weight — ML 0.865** Wt = 0.0364ML — 2.836 Seminal ductw.— ML __0.799#* Wvd = 0.0673ML — 6.519 Seminal duct w. — Testis w. 0.798** Wvd = 1.542Wt — 0.666 Seminal duct 1. — ML 0.357** Lvd =0.3612ML + 15.881 No. of spermatophore — ML 0.497** Nsp = 0.9846ML — 99.38 No. of spermatophore — Testis w. 0.255* Nsp = 11.680Wt + 7.993 No. of spermatophore — Seminal duct w. Spermatophore |. —ML 0.718** Nsp = 17.085Wvd — 9.185 0.703** Lsp =0.1349ML + 0.503 "Significant level at Soe iatelioe respectively. 20 10 % 100 50 (o) 10 15 20 25 cm Figure 5 Ratio of Impregnation of Sperm Bulbs on Females (lower panel) and Average Number of Sperm Bulbs (upper panel) by Mantle Length (Tune, 1976a) Tune (1976a) defined 3 stages of maturity: “imma- ture” for less than Ln — 2.5cm or 15.5cm ML, and “fully mature” for Ln over 7-5em or ML over 19cm. The stage between these two may be “mature.” Among immature” specimens, Wn 1g are allocated as “mature,” and those in which GW/BW exceeds 10% are allocated as “fully mature” (Figure 6) (GW = gonad weight; BW = body weight). REEL RL ASR 10 15 cm (ML) Figure 6 Ratio of Three Grades of Maturity by ML Classes (Tuna, 1976a) Female (upper panel), a: immature (W,, < 3g), b: mature (W,, > 38), ¢c: fully mature (ova present in oviduct) Male (lower panel), b: mature (Wt. 2g), c: fully mature (sper- matophores present) At the time of the first appearance of the squid schools in the southwestern waters off Taiwan, most of the females are immature. They gradually become mature and spawn in June. Along with the disappearance of the large-sized squid, another population of small squid appears in July- August and they become fully mature in September-Oc- tober. The third population that appears in November seems to mature in February-March of the next year. Therefore, the successive appearance of immature squids that mature several months apart well corresponds to the size composition. In conclusion, the Symplectoteuthis oua- laniensis population in Taiwanese waters is composed of 3 different (seasonal) subpopulations. Among the population that appears in the north of Luzon, some fully mature females are found. The schools that appear in the southwestern waters off Taiwan in June are composed of squids of advanced maturity. This school may spread in a clockwise direction but partially migrate up north to the Miyako Islands via the East of Taiwan. The mature individuals move ahead of the less mature squids. Spawning of these squids in the South China Sea is corroborated by SHojmma (1970) who re- ported rhynchoteuthion larvae which probably belong to Vol. 21; No. 1 this species, of 0.6- 6.4mm in summer. Rhynchoteuthi- ons of Todarodes pacificus never occur there in that season. FOOD Tunc et al. (1973) and Tune (1976b) found the maxi- mum content of a stomach to be 52.6g (at 27cm ML), but the contents usually weigh 1 - 3g. Empty (less than 0.5% of body weight), medium (less than 3%) and full (over 3%) stomachs occupy 62%, 33% and 4%, respec- tively, of examined stomachs. The relation between ML and weight of a full stomach (Ws) is: log Ws = 3.4576 log ML-6.751 According to this, the average full stomach contents of the squid between 10 and 25cm ML is 3.24 to 5.25 (Figure 7). The stomach contents are composed of pieces of squid flesh, horny rings, hooks, squid eyeballs, jaw plates, frag- ments of gladii, scales of fishes (probably 4 - 5cm in body length), vertebrae, fish eyeballs, crustacean remains, spermbulbs and parasites. The squids that preyed mainly on fish accounted for 36.7% (among them 2 preyed en- tirely on fish), on crustaceans - 20.5%, on squids - 18.4% 24 cm ML Figure 7 Relation between Content Weight of full Stomach (W,) and Mantle Length (Tunc, 1976b). mature; triangles: immature specimens Dots: fully mature; circles: THE VELIGER Page 93 and on unidentified substances - 9.8% of examined squid specimens. A regional tendency exists in prey-species composition : squid captured in the southwest of Taiwan contained mostly fish, in the east of Taiwan, a mixture of fish and squid, and around Okinawa more frequently crustaceans. Seasonal differences may be within the range of areal variation. The stomach content index (= SW/BW X 100) is higher in the early half of night (maximum 1.43) and lowers towards dawn. The relation between maturity and food intake is not clear, but the larger the squid grows, the smaller the index becomes. Younc (1975) stated that Symplectoteuthis oualant- ensis mainly preys upon fish. He reports that a single stomach contained remnants of 14 fishes. Other prey were enoploteuthid squids and various crustaceans, but the latter were thought to be from the ingested fish stomachs. WorMuTH (1976) listed 15 fish species that were identi- fied from otoliths: Stolephorus purpureus, Exocoetus volitans, Oxyporhamphus micropterus, Ceratoscopelus, Centrobrunchus, Vincigueria, 2 species each of Hyg- ophum, Diaphus, and Myctophum, and species of Centro- lophidae, Gempylidae and Holocentridae, all in Hawaiian waters. Besides squid beaks, he identified Hyaloteuthis pelagica, Onychoteuthis banksii and an enoploteuthid squid in the diet of S. oualaniensis. His description on a way of preying upon myctophids based on his observations on board ship is quite similar to what we have observed. PREDATORS No report has been available on predators of this squid in the Northwest Pacific, except a finding of Symplecto- teuthis oualaniensis in the stomach content vomited by an unidentified sea bird (T. O.). CiarkE (1966), Younc (1975), and WorMUTH (1976) listed as predators of Symplectoteuthis the sea birds: Phaeton rubricauda, Puffinus nativitatis, Pterodroma alba, Sterna fuscata, Anous stolidus, A. tenuirostris, A. minutus, Gygris alba, Porcelsterna caerulea, Sula piscator, S. sula and S. sp. As fish predators, Coryhaena hippurus, Gem- phylus aerpens and several tuna are listed by WorRMUTH (op. cit.). PARASITES Tune (1976a) found that 13.2% of females and 6.0% of males examined were infested by parasites, of which 92.6% were trematodes 0.6 - 6.0mm long. The rate of in- Page 94 festation is higher in the population in the southwest-south of Taiwan, lower in the east of Taiwan, and lowest in Oki- nawan waters. In general, the larger the squid, the higher the rate of infestation: 7.0% for immature, 15.5% for mature, and 34.8% for fully mature (average 13.2%). FISHING Symplectoteuthis oualaniensis has been commercially utilized only in Taiwan and Okinawa. The traditional fish- ing boat in Okinawa is a small row-boat of less than 1 ton. The annual squid and cuttlefish landings during 1947 to 1969 was 325 tons, and 70% was S. oualaniensis (Ryu- kyu FES, 1971). Motor-driven squid jigging machines have been used experimentally and the results revealed that the machines catch slightly smaller squids (Ryukyu FES, 1971). Symplectoteuthis oualaniensis is a byproduct in the Tai- wanese fishery. Tunc et al. (1973) found that S. owalani- ensis seldom stayed near the boat during experimental use of motor-driven jigging machines, even if they showed positive phototaxis to the fishing lights. The squid in the shadow of the boat are more easily attracted by jigs operated by machine, but those that stay in dim light at 15 - 25m depth are more accessible to hand lines. Poor catches are obtained during full moon. Another technical problem is that the arms of Symp- lectoteuthis oualaniensis are easily broken by motor-driven jiggers( originally designed for Todarodes pacificus) ; e. g., while 499 squids were captured, 365 broken arms (without whole animal) were hooked. This means almost half of the hooked squids were not taken aboard. The size of squid caught in Taiwan and Okinawa is good for bait for the tuna long line fishery. Symplectoteuthis oualaniensis also is good for human consumption and is being used on a small scale. However, attracting and keeping the schools under the fishing light for long duration and preventing broken arms are technical prob- lems to be overcome. THE VELIGER Vol. 21; No. 1 Literature Cited Crarxke, Matcoitm R. 1965. Large light organs on the dorsal surface of the squids, Omma- straphes pteropus, Symplectoteuthis oualaniensis and Dosidicus gigas. Proc. Malacol. Soc. London 36: 319 - 321 1966. A review of the systematics and ecology of oceanic squids. Adv. Mar. Biol. 4: 91 - 300; 59 figs. ITaAKuRA, HirosuH1 1977. Observations on squids at 29° N, 135° E. (150): 15-20 (in Japanese) Nesis, K. N. 1977. Population structure in the squid Sthenoteuthis oualantensts (Lesson, 1830) (Ommastrephidae) in the Western Tropical Pacific. Trud. Inst. Ocean. (107): 15-29 (in Russian) Oxinawa PREFECTURAL FISHERIES EXPERIMENTAL STATION 1972. Annual report for 1971 (mimeographed in Japanese): 1 - 132 OKuTANI, TAKASHI 1964. Studies on early life history of decapodan mollusca — I. A synoptic report on rhynchoteuthion larva of Todarodes pacificus. Bull. Tokai reg. Fish. Res. Lab. (41): 23-29 1970. A small collection of gastropod and decapod mollusks from the Seychelles Bank, Indian Ocean, by the Training Vessel Koyo-Maru in 1968. Japan. Journ. Malac. 29 (4): 123-130; 1 pit. 1974. Problem in studies on early life history of oceanic cephalopods. Mar. Sci. 6: 277 - 282 (in Japanese) OxuTANI, TAKASHI & JoHN ARTHUR McGowan 1969. Systematics, distribution and abundance of the epiplanktonic squid (Cephalopoda, Decapoda) larvae of the California current April, 1954 - March, 1957. Bull. Scripps Inst. Oceanogr. 14: 1-90; 36 figs. Ryuxyu FisHerizs EXPERIMENTAL STATION 1971. Annual report for 1970. 1-120 (mimeographed, in Japanese) SHojima, YOICHI 1970. Cephalopod larvae and eggs taken at the sea surface in the northern South China Sea — I. Bull. Seikai reg. Fish. Res. Lab. (38): 61-77 (in Japanese) Tune, In-Hsiu 1975. Squids and exploration of their resources. ral Reconstr. Sp. Publ. (21): 1-56 (in Chinese) 1976a. On the reproduction of common squid, Symplectoteuthis oua- laniensis (Lesson). Rept. Inst. Fish. Biol., Min. Econ. Aff. & Nat. Taiwan Univ. 3 (2): 26-48 (in Chinese) 1976b. On the food habit of common squid, Symplectoteuthts oualani- ensis (Lesson). Rept. Inst. Fish. Biol., Min. Econ. Aff. & Nat. Taiwan Univ. 3 (2): 49-66 (in Chinese) Tune, In-Hsiu, Cui-SHENG Lan & CHan-CuHin Hu 1973. The preliminary investigation for exploitation of common squid resources, Rept. Inst. Fish. Biol., Min. Econ. Aff. & Nat. Taiwan Univ. 3 (1): 211-247 (in Chinese) WormutTH, JoHn Hazen 1976. The biogeography and numerical taxonomy of the oegopsid squid family Ommastrephidae in the Pacific Ocean. Bull. Scripps Inst. Oceanogr. 23: 1 - 90 Yamamoto, Koicui & TAKASHI OKUTANI 1975. Studies on early life history of decapodan mollusca — V. System- atics and distribution of epipelagic larvae of decapod cephalopods in the southwestern waters of Japan during the summer in 1970. Bull. Tokai Reg. Fish. Res. Lab. (83): 45-96 Youna, RicHarp EDwARD 1975. A brief review of the biology of the oceanic squid, Symplecto- teuthis oualaniensis (Lesson). Comp. Biochem. Physiol. 52B: 141 - 143 Zuezv, G. V, K. N. Nests « C. M. NicMaTuLIN 1975. System and evolution of the squid genera Ommastrephes and Symplectoteuthis (Cephalopoda, Ommastrephidae). Zool. Zhurn. 54 (10): 1468-1479 (in Russian), Fune-to-Kisho Joint Comm. Ru- Vol. 21; No. 1 THE VELIGER Page 95 Possible Predation on Nautilus pompilius JOHN K. TUCKER Department of Biological Sciences, Illinois State University, Normal, Illinois 61761 ROYAL H. MAPES Department of Geology, University of Iowa, Iowa City, Iowa 52242 (1 Plate; 1 Text figure) INTRODUCTION THE MORE RECENT REVIEWS of the natural history of Nautilus pompilius Linnaeus, 1758 (MILLER, 1947; SuI- MANSKY, 1962; STENZEL, 1964) make little mention of predators or predation. WILLEY (1902) reported seeing Nautilus specimens in which the hood had been bitten and attributed this to possible attacks by fish, sharks or conger eels and nuptial combats. More recently, HAVEN (1972) reported fighting between young and adult males of N. pompilius; however, this report could also be interpreted as attempted cannibalism. As far as we can determine, no analytical studies have been done on the possible extent of predation on Nautilus pompilius. While the present paper was being reviewed after submission for publication, FAULKNER (1977) men- tions the existence of boreholes in living Nautilus from New Caledonia. Although he suggests that octopus were the possible borers, he provides no detailed analysis or description of the boreholes. In the present paper, we analyze boreholes found in numerous specimens of N. pompilius and suggest that some boring organism is an important predator on Nautilus. We also describe the borings and responses observed, consider the identity of the boring organism, and analyze the pattern of boreholes and the possible frequency of predation on N. pompilius by these organisms. MATERIAL anp METHODS Except where noted, all Nautilus pompilius examined in this study were purchased as empty shells from commer- cial sources within the last 3 years. All were imported by Filipino suppliers and were presumably collected in the vicinity of the Philippine Islands. We do not know if the shells contained animals when they were collected. Speci- mens examined include: Harvard University, Museum of Comparative Zoology: N. pompilius, MCZ 184601, 142- 510, and 2 uncatalogued specimens; N. repertus, MCZ 211689; University of Iowa: N. macromphalus, SUI 40081 - 40093; N. scrobiculatus, SUI 623; N. pompilius, SUI 1090, 1092, 40045 - 40079, 40096 - 40100, 42469 - 42477; and N. cf. N. repertus, SUI 40094 - 40095. Meas- urements of borehole outer diameter (greatest dimension) and shell parameters were made with vernier calipers. The diameter of the shell was measured at the borehole. Diameters of the largest shells were measured with a milli- meter rule. Terminology follows CARRIKER & YOCHELSON (1968). RESULTS We examined 150 shells of Nautilus pompilius; 43 (28.7 %) of them were found to be bored. Boreholes were also observed in other species of Nautilus: the frequencies of borings were 1 of 13 N. macromphalus, 3 of 3 N. reper- tus and 1 of 1 N. scrobiculatus. The sample sizes for these species are too small for analysis and the remainder of the paper will be concerned with N. pompzulius. A smaller percentage (24%) of juvenile shells (those without a black lining on the inner edge of the aperture) than adults (79%) had boreholes, but the sample size of adults (n = 15) is smaller than that of juveniles (n= 135). The virtual absence of bored shells in the range of 60 - 11omm Page 96 diameter is due to our lack of specimens in that size range. A total of 11 specimens (6 adults and 5 juveniles) had more than one borehole. The frequency (50%) of adults with multiple borings is higher than the frequency (16%) of multiply bored juveniles (X? = 21.8, 1 df, p < 0.005). The largest number of complete boreholes observed on any single specimen was 4. Boreholes are regularly situated relative to the height of the whorl. Only 4 of 60 boreholes were in the lower lateral and umbilical lateral regions of the shell. The mean position of the boreholes was at 3 the distance from the umbilical shoulders to the venter (7. ¢., generally in the ventrolateral region of the body chamber). The outer diameters of the boreholes are significantly related to the diameters of the shells at the borings (r= 0.76, p = 0.001). Regression lines (Y = 0.012 X +0.93; 200 180 160 Shell Diameter at Borehole (mm) 8 Maximum Diameter of Boring (mm) Figure 7 Scattergram showing the distribution of maximum borehole dia- meter compared to the conch diameter at the borehole. Open circles represent incomplete borings; closed circles represent com- plete borings THE VELIGER Vol. 21; No. 1 X = 48.63 Y — 16.53) computed from the data in Figure 7 are significantly different from o at the 95% confidence level. If incomplete boreholes are included in the calcu- lations, the equations (Y = 0.011 X +0.89; X = 44.90 Y — 1.72) still do not contain o. The 7 value is reduced to 0.70, but is still significant (p < 0.001). The outer openings of the boreholes are irregular in outline ranging from circular to nearly cruciform. How- ever, they all appear to be variations on a basic plan. At the inception of boring, the outer opening is almost cir- cular. As boring proceeded, the circular outer hole de- veloped a variably shaped elongation in what appears to be a random orientation. Incomplete boreholes have a bossed bottom. The height of the boss is smaller in in- complete holes that deeply penetrate the nacreous layer than in shallower holes (Figure 5). The final borehole shape is a circular outer opening with 2 chamfers opposite each other that extend beyond the countersunk edge of the borehole (Figure 4). Incomplete holes that penetrate deeply into the nacreous layer of the shell appear to be more irregular than those not reaching it. The interior openings of the completed borings range from circular to elliptical (Figure 6). No correlation between the shapes of the inner and outer openings was noted. Shelves were present in most completed borings. Borehole longitudinal sections vary from truncated circular to irregularly coni- cal to'truncated spherical parabolic boreholes. Many bore- holes were countersunk as well. The intensity of the reaction of Nautilus to borings varied from none to extreme (Figure 1); 13 specimens showed evidence of a response. Most reactions were con- fined to the formation of a small black discoloration around the interior opening of the borehole. The possibil- ity that this was produced by the boring organism cannot be ruled out. One specimen (Figure 1) formed massive blister-like pearls of what is probably calcium carbonate together with black organic matter over the interior open- ing of one borehole and a thick black layer with a thin calcium carbonate layer around a second borehole. This latter borehole is not plugged, whereas the former appears to be completely plugged. Explanation of Figures 1 to 6 Figure 1: Internal view of Nautilus pompilius with blister-like organic and calcium carbonate deposits around boreholes (SUI 40039) x1 Figure 2: External view of the specimen shown in Figure 1 show- ing the positions of the boreholes (SUI 40039) X11 Figure 3: Nautilus pompilius showing boring at about 160° of arc from the estimated position of the nepionic constriction (SUI 4.0044) about X 2.1 Figure 4: Initially circular boring with slit-like internal opening (SUI 40042; whitened with NH,Cl) X5 Figure 5: An unfinished boring with a bossed bottom from the right side of the specimen shown in Figures 1 and 2 (SUI 40039; whitened with NH,Cl) x5 Figure 6: Oval shaped boring on the right side of the specimen shown in Figures 1 and 2 (SUI 40039; whitened with NH,Cl) X 5 Tue VELIGER, Vol. 21, No. 1 Figure 7 ligure Figure 2 Figure 4 [Tucker & Mapes] Figures 1 to 6 eh orf rs J J See es € i Figure 5 : bay pak Bere ef ty #2 Vol. 21; No. 1 DISCUSSION CARRIKER & YOCHELSON (1968) reviewed what was then known of predatory boring organisms which included turbellarians, coleoid cephalopods and gastropods. Tur- bellarians produce boreholes that are much smaller (0.15 > 7) on Isociona lithophoenix, on Esperiopsis originals “) Halichondria panicea ‘” '* ¥) Halichondria panicea ‘> *) Myxilla incrustans, Mycale adhaerens \” Stylissa stipitata, Tedania sp., Craniella sp., Syringella amphispicula on Halichondria panicea, on Myxilla incrustans ” Adocia gellindra Myxilla agennes, Paresperella psila, Zygherpe hyaloderma, Mycale macginitiei, Prianos sp. °°”) Mycale adhaerens, Haliclona permollis, Halichondria panicea Lissodendoryx firma ®) Vol. 21; No. 1 Nudibranch Species Diaulula sandiegensis Porodoridacea DENDRODORIDIDAE Donopsilla albopunctata DENDRONOTACEA TRITONIDAE Tritonia diomedea Tritonia festiva Tochuina tetraquetra DENDRONOTIDAE Dendronotus albus Dendronotus diversicolor Dendronotus frondosus Dendronotus iris Dendronotus subramosus TETHYIDAE Melibe leonina DoTONDAE Doto amyra THE VELIGER Page 113 Table 1 (continued ) Food Item on Halichondria panicea, on Myzxilla incrustans, Petrosia dura Halichondria bowerbanki ©) Haliclona permollis ‘” Haliclona sp. “* Cliona celata, Ficulina suberea, Acarnus erithacus, Suberites sp. ‘”) Virgullaria sp. Ptilosarcus gurneyi 7°) Clavularia sp. “? Ptilosarcus gurneyi “'% 7°) Lophogorgia chilensis “*) Gersemia rubiformis Ptilosarcus gurneyi *™) on Plumularia sp. ©? on Abietinaria spp., on Sertularella tricuspidata, on Hydrallmania dis- tans (51) Tubularia indivisa * *) Tubularia larynx ‘* #) Dynamena pumila, Hydrallmania falcata “© Sertularia argentea Sertularia cupressina on Abietinaria abietina on Sertularia argentea “* 4”) Coryne sp. '3) on Aglaophenia ) on Sertularia cupressina “*) Hydractinia echinata ‘) Tubularia crocea, Obelia spp. °” Sertularia dichotoma Botryllus schlosseri ‘4 Pachycerianthus fimbriatus ‘® ®) Aglaophenia struthionides Gammarids, Caprellids Copepods (1, 93, 74) Amphipods ‘#) on Obelia ‘) Page 114 Nudibranch Species ARMINACEA EUARMINOIDEA ARMINIDAE Armina californica PACHYGNATHA DironDAE Dirona albolineata Dirona picta ZEPHYRINIDAE Antiopella barbarensis AEOLIDACEA EUEOLIDOIDEA PLEUROPROCTA CoryPHELLIDAE Coryphella trilineata FLABELLINIDAE Flabellinopsis todinea ACLEIOPROCTA EUBRANCHIDAE Cumanotinae Cumanotus beaumonti Eubranchinae Eubranchus olivaceus Eubranchus rustyus CuTHONIDAE Precuthoninae Precuthona divae Cuthoninae Tenellia pallida Catriona alpha THE VELIGER Table 1 (continued) Food Item Renilla koellikeri © ) Renilla ‘amethystina’ ‘* Ptilosarcus gurneyi ‘7: ®) Vol. 21; No. 1 Margarites pupillus, M. helicinus, Lacuna carinatus, ectoprocts, hyd- roids, small crustaceans, sponges, barnacles, tunicates ‘*) on Thaumatoporella sp. ‘?) Aglaophenia sp. Celleporella hyalina 7) Bugula californica ‘) Corymorpha palma on Eudendrium sp., on Tubularia crocea ©) Eudendrium ramosum ‘”) Diplosoma pizoni Tubularia crocea " on Obelia longissima +) on Hydractinia sp. ‘*) on Plumularia lagenifera ‘* on Obelia on Hydractinia sp. "> * °) Cordylophora lacustris ‘“) Gonothyraea loven: ‘) Protohydra leuckarti, Psammohydra sp. ‘° on Obelia dichatoma “* Laomedea loveni, L. longissima, Cordylophora caspia Obelia, Podocoryne ‘*) Tubulana marina, T. sp., on Syncoryne eximia, on Obelia sp. ‘? on Tubularia crocea © Vol. 21; No. 1 THE VELIGER Page 115 Table 1 (continued) Nudibranch Species FIONIDAE Fiona pinnata Food Item Porpita sp. ‘* Lepas anatifera ‘” barnacles “*® Lepas ‘* *) Lepas anserifera Velella velella % *% ») Velella spirans ‘” Velella 5”) CLEIOPROCTA FACELINIDAE Hermissenda crassicornis Ptilosarcus gurneyt ‘”) Obelia spp., canibalistic ‘*) Phidiana pugnax AEOLIDIDAE Aeolidia papillosa Hydractinia sp. Tealia crassicornis 3 3 ©) Actinia, “Anthea”? “® Actinia equina “5 #:% 7) Anemonia sulcata “* ®) Diadumene cincta ‘Metridium marginatum’ ‘*°) Metridium senile 5 6:6: 6% 7. P) Sagartia troglodytes “ %) Sagartiogeton undata Stomphia coccinea ‘) Tealia felina “> # & &) Tubularia indivisa “) Tealiopsis stella ‘> Metridium dianthus “”) Epiactis prolifera, Anthopleura xanthogrammica, Diadumene luciae, Tealia coriacea, Anthopleura artemisia, Corynactis californica ‘ Actinothoe sphyrodeta, Anthopleura balli, Sagartia elegans, Cereus pedunculatus, Aiptasia couchi, Corynactis viridis “) Anthopleura elegantissima “3:3 ™ Aeolidiella takanositmensis Cerberilla mosslandica SPURILLIDAE Spurilla oliviae Spurilla chromosoma Sagartia ‘*) burrowing anemone ‘*) Metridium senile ‘* ”) Metridium senile ‘*2) 22 In order to conserve space the full citation of the taxa discussed and listed was excluded from the table. It is given in alphabetical order below. Mollusca Acanthodoris nanaimoensis O'Donoghue, 1921; A. pilosa (Abild- gaard, 1789); Acolidia papillosa (Linnaeus, 1761); Aeolidiella takanosimensis Baba, 1930; Aldisa sanguinea (Cooper, 1862); An- cula pacifica MacFarland, 1905; Anisodoris nobilis (MacFarland, 1905); Antiopella barbarensis (Cooper, 1863); Archidoris monterey- ensis (Cooper, 1862); A. odhneri (MacFarland, 1966); Armina californica (Cooper, 1862) Cadlina flavomaculata MacFarland, 1905; C. luteomarginata Mac- Farland, 1966; C. modesta MacFarland, 1966; Catriona alpha (Baba Page 116 « Hamatani, 1963); Cerberilla mosslandica McDonald « Nybakken, 1975; Chromodoris mcfarlandi Cockerell, 1902; C. porterae Cock- erell, 1902; Corambe pacifica MacFarland « O’Donoghue, 1929; Coryphella trilineata O’Donoghue, 1921; Cumanotus beaumonti (Eliot, 1906) Dendronotus albus MacFarland, 1966; D. diversicolor Robilliard, 1970; D. frondosus (Ascanius, 1774); D. iris (Cooper, 1863); D. subramosus MacFarland, 1966; Diaulula sandiegensis (Cooper, 1862); Dirona albolineata Cockerell & Eliot, 1905; D. picta Cockerell « Eliot, 1905; Discodoris heathi MacFarland, 1905; Doridella steinbergae (Lance, 1962); Doriopsilla albopunctata (Cooper, 1863) Eubranchus olivaceus (O’Donoghue, 1922); E. rustyus (Marcus 1961) Fiona pinnata (Eschscholtz, 1831) ; Flabellinopsis iodinea (Cooper, 1862) Hallaxa chani Gosliner « Williams, 1975; Hermissenda crassicornis (Eschscholtz, 1831); Hopkinsia rosacea MacFarland, 1905; Hypselo- doris californiensis (Bergh, 1879) Lacuna carinata Gould, 1848; Laila cockerelli MacFarland, 1905 Margarites helicinus (Phipps, 1774); M. pupillus (Gould, 1849) ; Melibe leonina (Gould, 1852) Onchidoris bilamellata (Linnaeus, 1767); O. muricata (O. FE Miller, 1776) Phidiana pugnax Lance, 1962; Polycera atra MacFarland, 1905; found on the ascidian Didemnum carnulentum Ritter & Forsyth, 1917. The nudibranchs had grazed large portions of the ascidian. Several very large (over 100mm) specimens of both Diaulula sandiegensis and Archidoris montereyensis, a- long with their nidosomes, have been collected on a sponge (tentatively identified as Halichondria bowerbanki Burton, 1930) in an erosion channel in the upper third of Elkhorn Slough, Monterey County, California. As in many of the above cases, depressions had been rasped into the sponge. Further, this was the only species of sponge noted to be present in the channel and hence, possibly the only available food. Over a period of 3 years, large numbers of Cumanotus beaumonti, frequently with their nidosomes, have been observed on and collected from the gymnoblastoid hydroid Tubularia crocea (Agassiz, 1862). We have never found C. beaumonti on any substrate other than T. crocea, and if the nudibranch is removed from the hydroid, it imme- diately seeks to return to the hydroid. In the laboratory, the eolids were observed to feed upon the polyps of the hydroid. On 12 April 1977, large numbers of the eolid Phidtana pugnax were found in close association with the gymno- blastoid hydroid Hydractinia sp. at Carmel Point, Monte- rey County, California. Later, in laboratory aquaria, the Hydractinia colonies were quickly consumed by P. pug- nax. We have never observed them consuming other hyd- THE VELIGER Vol. 21; No. 1 P. hedgpethi Marcus, 1964; P. zosterae O’Donoghue, 1924; Precu- thona divae Marcus, 1961 Rostanga pulchra MacFarland, 1905 Spurilla chromosoma Cockerell « Eliot, 1905; S. oliviae (MacFar- land, 1966) Tenellia pallida (Alder « Hancock, 1854); Tochuina tetraquetra (Pallas, 1788) ; Triopha carpenteri (Stearns, 1873) ; Trtopha macu- lata MacFarland, 1905; Tritonia diomedea Bergh, 1894; Tritonta festiva (Stearns, 1873) Non-Mollusca Adocia gelindra (de Laubenfels, 1932); Aplysilla glactalis (Dybowski, 1880) Barentsia ramosa (Robertson, 1900) ; Bugula californica Robertson, 1905; B. pacifica Robertson, 1905 Didemnum carnulentum Ritter & Forsyth, 1917 Eurystomella bilabiata (Hincks, 1884) Halichondria bowerbanki (Burton, 1930); H. paniceum (Pallas, 1766) ; Hincksina velata (Hincks, 1881) ; Hymendesmia brepha (de Laubenfels, 1930) Lepas anatifera Linnaeus, 1758; Lissodendoryx firma (Lambe, 1895) Metridium senile (Linnaeus, 1767) Pachycerianthus fimbriatus (McMurrich, 1910) ; Pttlosarcus gurneyi (Gray, 1860) Tubularia crocea (Agassiz, 1862) roids, though they are known to attack other nudibranchs under crowded aquarium conditions (LaNcE, 1962a). Over a period of several years, small (3 to 7mm total length) specimens of Onchidoris muricata have been col- lected, almost always on the encrusting bryozoan Reginella mucronata (Canu «& Bassler, 1923). PREVIOUS FOOD RECORDS Table 1 summarizes our search of the literature relevant to the recorded food habits of California nudibranchs. In- cluded are the new data reported in this paper as well as additional personal observations of nudibranchs on pos- sible food species which they were not actually seen to ingest (indicated by ’). Where more than a single food item is listed, the order of listing does not imply prefer- ence (which is often unknown) of the nudibranch. We include the table as a guide to those who may find it useful in doing additional ecological or experimental studies of California nudibranchs. DISCUSSION The summary table includes certain nudibranch species from California that are also found in other geographical Vol. 21; No. 1 THE VELIGER Page 117 areas (e.g. Aeolidia papillosa, Acanthodoris pilosa, Onchidoris muricata, Dendronotus frondosus, and others). Hence, the food items reported here may not necessarily be present in California. Widely distributed nudibranch species may well have additional food items or different preferences in different geographical locations. Certainly for A. papillosa, the studies of WATERS (1973) suggest that the major prey preferences differ between those occurring in Atlantic waters and those occurring in Pacific waters. Such differing prey preferences have not, to our knowledge, been investigated for other nudibranchs with wide geographical ranges. The whole field of prey pref- erence studies for most California nudibranchs remains relatively little explored, and we hope this review may stimulate additional work. ACKNOWLEDGMENTS We wish to thank Mr. R. Shane Anderson for providing data, Dr. Penny Morris for identifying some of the bryo- zoans, Mr. Jeff Goddard for bringing to our attention additional references, Mr. John Cooper for providing data and additional references, Mrs. Doris Baron of Moss Landing Marine Laboratories library for the excellent help with literature, and the senior author’s wife, Andrea McDonald, for help in collecting specimens and data in the field. Literature Cited 1 Ajesxa, Ricnarp A. & James Wittarp NysAKKEN 1976. Contributions to the biology of Melibe leonina (Gould, 1852) (Mollusca : Opisthobranchia). The Veliger 19(1): 19-26; 2 pits.; 5 text figs. (1 July 1976) 2 Barngs, Harotp e« H. T. Poweit 1954. Onchidorts fusca (Miller), a predator of barnacles. Journ. Anim. Ecol. 23 (2): 361 - 363; plt. 2 3 Beuyrentz, ALyson 1931. Trekk av Lamellidoris muricata’s biologi og av dens generals- oon bygning. Nyt. Mag. Naturv. Oslo 70: 1-26; 19 text 4 Bexrcx, Lupwic Sornus Rupo.Pu 1880. On the nudibranchiate gasteropod Mollusca of the North Pacific Ocean, with special reference to those of Alaska. Part II. Proc. Acad. Nat. Sci. Philadelphia $2: 40 - 127; plts. 9-16 (March-June) 5 Bgrtscu, Hans 1968. _ Effect of feeding by Armina californica on the bioluminescence of Renilla koellikeri. The Veliger 10 (4): 440-441 (1 April 1968) 6 Bierr, R. 1966. Feeding preferences and rates of the snail, Janthina prolongata, the barnacle, Lepas anserifera, the nudibranchs, Glaucus atlanticus and Fiona pinnata, and the food web in the marine neuston. Publ. Seto Mar. Biol. Lab. 14: 161 - 170; plts. 3, 4; 1 text fig. 7 Broom, STEPHEN A. 1976. | Morphological correlation between dorid nudibranch predators and sponge prey. The Veliger 18 (3): 289-301; 1 text fig.; 5 tables (1 January 1976) 8 Burn, Ropert FE 1966. Descriptions of Australian Eolidacea (Mollusca: Opisthobran- chia). 4. The genera Pleurolidia, Fiona, Learchis, and Cerberilla from Lord Howe Island. 16 text figs. 9 CarerooTt, THomas H. 1967. Growth and nutrition of three species of opisthobranch molluscs. Journ. Comp. Biochem. Physioi. 21 (3): 627 - 652 10 CHRISTENSEN, Hans 1977. Feeding and reproduction in Precuthona peachi (Moltusca: Nudibranchia). Ophelia 16 (1): 131-142; 9 text figs. 11 Crarx, Kerry B. 1975. | Nudibranch life cycles in the Northwest Atlantic and their re- lationship to the ecology of fouling communities. Helgol. wiss. Meeresunters. 27: 28-69; 14 text figs. 12 Coroan, NATHANIEL 1913. Some additions to the nudibranch fauna of Co. Dublin. Irish Nat. 22: 165 - 168 13 Cook, Emiry F 1962. A study of food choices of two opisthobranchs, Rostanga pulchra MacFarland and Archidoris montereyensis (Cooper). The Veliger 4(4) 194-196; 4 text figs. (1 April 1962) 14 Cufnot, Lucien 1927. Contributions a la faune du Bassin d’Arcachon. IX. Revue géné- rale de Ja faune et bibliographie. Bull. Stat. Biol. d’Arcachon 24: 229 - 305; 5 text figs. 15 Epmunps, Marcos, G. W. Potts, R. C. SwInFEN & Virointa L, WaTERS 1974. The feeding preferences of Aeolidia papillosa (L.) (Mollusca: Nudibranchia). Journ. Mar. Biol. Assoc. U. K. 54: 939 - 947 16 Exiot, Caaritzs Norton EpcecomBe 1910. A monograph of the British nudibranchiate Mollusca. Suppl. Ray Soc. London, part VIII: 198 pp.; 8 plts. 17 Ervin, Dav W. 1976. Feeding of a dorid nudibranch, Diaulula sandiegensis, on the sponge Haliclona permollis. The Veliger 19 (2): 194-198; 1 text fig (1 October 1976) Journ. malacol. Soc. Australia 1 (10): 21-34 18 Fournier, ANNE 1969. Anatomie, histologie, et histochimie du tube digestif de Pelto- doris atromaculata Bergh. Vie et Milieu 20: 73 - 93; photos 1-6 19 Gomez, Epoarpo D. 1973. Observations on feeding and prey specificity of Thitonta festive (Stearns) with comments on other tritoniids (Mollusca : Opistho- branchia). The Veliger 16 (2): 163 - 165; 1 pit. (1 Oct. 1973) 20 Gos.iner, TERRENCE & Gary C. Wriiams 1973. The occurrence of Polycera zosterae O'Donoghue, 1924 in the Bodega Bay region, California, with notes in its natural history (Gastro- poda : Nudibranchia). The Veliger 15 (3): 252-253; 2 text figs. (1 January 1973) 21 Granam, ALASTAIR 1955. Molluscan diets. Proc. Malacol. Soc. London 91 (3-4): 144 - 159 22 Grant, Rosert EDMOND 1826. On the sounds produced unter water by Tritonia erborescens. Edinb. Philos. Journ. 14: 165, 185 - 186 23 Harrrs, Larry G. 1973. Nudibranch zssociations. In Current Topica in Comparative Pathobiology, ed. T. C. Cheng. Academic Press, Inc., New York. 2: 213 - 315; 6 figs. 24 HerpmMan, WittiAm ApBotTr 1886. | On the structure and functions of the cerata or dorsal papillae in some nudibranchiate Mollusca. Quart. Journ. Micros. Sci. 31: 41 - 63; plts. 6 - 10 25 Hurst, ANNE 1968. The feeding mechanism and behavior of the opisthobranch Melt- be leonina. Symp. Zool. Soc. London 92: 151-166; 8 text figs. 26 KasTENDIEK, Jon 1976. Behavior of the sea pansy Renilla kollikeri Pfeffer (Coelentera- ta: Pennatulacea) and its influence on the distribution and biological interactions of the species. Biol. Bull. 151 (3): 518-537; 9 figa. 27 Krorpp, BENJAMIN 1931. The pigment of Velella spirans and Fiona marina. Biol. Bull Woods Hole 60: 120 - 129 28 Lanczg, James Ropert 1961. _A distributional list of southern California opisthobranchs. The Veliger 4 (2): 64-69 (1 October 1961) 29 ——————__ ) 1962a. Two new opisthobranch mollusks from southern California. The Veliger 4 (3): 155 - 159; pit. 38; 8 text figs. (1 January 1962) 9 % 1962b. A new Stiliger and a new Corambella (Mollusca: Opisthobran- chia) from the northwestern [sic] Pacific. The Veliger 5 (1): 33-98; pit. 6; 10 text figs. (1 July 1962) Page 118 3t Lzewse., Georce S. & James Rosert Lance 1975. Detached epidermal sheaths of Lophogorgia chilensis as a food for Polycera atra. The Veliger 17 (4): 346 (1 April 1975) 32 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) 33 MacFartanp, Frank Macgz e CHarLtes Henry O’DoNoGHUE 1929. A new species of Corambe from the Pacific coast of North Amer- ica. Proc. Calif. Acad. Sci. (4) 18 (1): 1-27; plts. 1-3 34 Marcus, Ernst 1961. | Opisthobranch mollusks from California. The Veliger $ (Supplmt. 1): 1-85; pits. 1-10 (1 February 1961) 35 Marcus, Eve.ine pu Bois-REYMoND & ErNst Marcus 1955. Uber Sand Opisthobranchia. Kieler Meeresforsch. 11 (2): 230 - 243; plts. 36 - 38 36 McBetH, JAMES WARREN 1968. Feeding behavior of Corambella steinbergae. 11 (2): 145 - 146 The Veliger (1 October 1968) 37 1971. Studies on the food of nudibranchs. 158 - 161 38 McDonatp, Gary R. & James WiLtLtarD NyBAKEEN 1975. Cerberilia mosslandica, a new eolid nudibranch from Monterey Bay, California (Mollusca : Opisthobranchia). The Veliger 17 (4): 378-382; 2 text figs. (1 April 1975) 39 McMitian, Nora FISHER 1942. Food of nudibranchs. 40 Miier, MicHaEL CHARLES 1961. Distribution and food of the nudibranchiate Mollusca of the South of the Isle of Man. Journ. Anim. Ecol. 30 (1): 95-116 The Veliger 14 (2): (1 October 1971) Journ. Conchol. 21: 327 I eS 1962. Annual cycles of some Manx nudibranchs, with a discussion of the problem of migration. Journ. Anim. Ecol 31 (3): 545-5693 12 text figs. 42 Morsgz, M. Patricia 1968. Functional morphology of the digestive system of the nudibranch mollusc Acanthodoris pilosa. Biol. Bull. 194 (2): 305 - 319; 9 text figs. 43 Grae 1969. On the feeding of the nudibranch Coryphella verrucosa rufibran- chialis, with a discussion of its taxonomy. The Nautilus 8g (2): 37 - 40 44 Navire, ANpRE 1926. Notes sur les éolidiens. Un éolidien d’eau saum4tre. Origine des nématocystes. Zooxanthelles et homochromie. Rev. Suisse Zool. 33: 251-286; 9 text figs. 45 NyBAKKEN, James WILLARD & JAMES EASTMAN 1977. Food preference, food availability and resource partitioning in Triopha maculata and Triopha carpenteri (Opisthobranchia : Nudi- branchia). The Veliger 19 (3): 279 - 289; 4 text figs.; 6 tables (1 January 1977) 46 O'DonocHve, CHartes Henry 1922. Notes on the nudibranchiate Mollusca from the Vancouver Is- land region. 1. Colour variations. Trans. Roy. Canad. Inst. 14 (1): 123 - 130; plt. 2 47 Pe.sENeer, PauL 1911. | Recherches sur l’embryologie des gastropodes. Roy. Belg. (2) 6: 1 - 167 48 Ports, G. W. 1970. The ecology of Onchidoris fusca (Nudibranchia). Journ. Marine Biol. Assoc. U. K. 50 (2): 269 - 292; 2 plts.; 8 text figs. 49 Purcuon, R. Denison 1947. Studies on the biology of the Bristol Channel. XVII. The lit- toral and sublittoral fauna of the northern shores near Cardiff. Proc. Bristol Nat. Soc. 27 (3): 285-310 50 Rasmussen, Erix 1944, Faunistic and biological notes on marine invertebrates, I. The eggs and larvae of Brachystomia rissoides (Hanl.), Eulimella nitidissimma (Mont.), Retusa truncatula (Brug.) and Embletonia pallida (Alder and Hancock), (Gastropoda marina). Vidensk. Meddel. Dansk. Naturh. Foren. 107: 207 - 233; 20 text figs. 51 RosrLuiarp, Gorpon ALLAN 1970. The systematics and some aspects of the ecology of the genus Dendronotus (Gastropoda : Nudibranchia). The Veliger 12 (4): 433 - 479; plts. 63, 64; 28 text figs. (1 April 1970) Mém. Acad. $3 Se 1971a. Predation by the nudibranch Dirona albolineata on three species of prosobranchs. Pacif. Sci. 25 (3): 429-435 THE VELIGER Vol. 21; No. 1 53 ite eae 1971b. A new species of Polycera (Opisthobranchia: Mollusca) from the northeastern Pacific with notes on other species. Syesis 4: 235 to 243; 10 text figs. 54. 1971c. Range extensions of some northeast Pacific nudibranchs (Mol- lusca : Gastropoda : Opisthobranchia) to Washington and British Co- lumbia, with notes on their biology. The Veliger 14 (2): 162 - 165 (1 October 1971) 55 Rosson, Exarne A. 1961. The swimming response and its pacemaker system in the ane- mone Stomphia coccinea. Journ. exp. Biol. 38 (3): 685 - 694 56 Russe.Lt, Henry DruMMOND 1942. Observations on the feeding of Aeolidia papillosa L., with notes on the hatching of the veligers of Cuthona amoena A. & H. The Nautilus 55 (3): 80-82 57 Savitov, A. I. 1956. Floating biocoenosis in the Pacific Ocean based on the material of the expedition of the Institute of Oceanology of the Academy of Sciences, USSR. Priroda 3: 62-68 (in Russian) 58 ScHMEKEL, RENATE LUISE 1968. | Ascoglossa, Notaspidea und Nudibranchia im Litoral des Golfes von Neapel. Rev. Suisse Zool. 75 (6): 103-155; 21 text figs. 59 Seep, R. 1976. Observations on the ecology of Membranipora (Bryozoa) and a major predator, Doridella steinbergae, along with fronds of Laminaria saccharina at Friday Harbor, Washington. Journ. Exper. Mar. Biol. Ecol. 24 (1): 1-18 60 Smirx, Rarpo InNcrAmM & James T. CARLTON 1975. Light’s Manual: Intertidal Invertebrates of the Central Califor- nia Coast. 3rd edit. Univ. Calif: Press, Berkeley. xviiit716 pp.; 156 plts. 61 SweENNEN, CHARLES 1961. Data on distribution, reproduction and ecology of the nudi- branchiate Mollusca occurring in the Netherlands. Nether]. Journ. Sea Res. 1 (1-2): 191-240 62 THompson, THomas EVERETT 1961. Observations of the life history of the nudibranch Onchidorts muricata (Miller). Proc. Malacol Soc. London $4 (5): 239 - 242 6g —————_- 1964. Grazing and the life cycles of British nudibranchs. Ta: D.-J. Crisp (ed.) Grazing in terrestrial and marine environments, pp. 275-297. Blackwell, Oxford, England 64 1971. Tritoniidae from the North American Pacific coast (Mollusca: Opisthobranchia). The Veliger 13 (4): 333-338; 3 text figs. (1 April 1971) 65 Turner, Cwarzes H., Eart E. Esert & Rosert R. Given 1969. | Man-made reef ecology. Calif. Fish & Game, Fish Bul. 146: 1-221; 74 text figs. 66 Wa ton, C. L. 1908. | Nudibranchiata collected in the North Sea by the SS. Huxley during July and August, 1907. | Journ. Mar. Biol. Assoc. U. K. 8: 227 - 240 67 Waters, Virani L. 1973. Food preference of the nudibranch Aeolidia papillosa, and the effect of the defenses of the prey on predation. The Veliger 51 (3): 174-192; 5 text figs. (1 January 1973) 68 WicksTen, Mary K. e Joun D. DeMartini 1973. Observations of the feeding habits of Tochuina tetraquetre (Pal- las) (Gastropoda : Tritoniidae). The Veliger 15 (3): 195 (1 January 1973) 69 Wosper, Don R. 1970. A report on the feeding of Dendronotus iris on the anthozoan Cerianthus sp. from Monterey Bay, California. The Veliger 12 (4): 383 - 387; plts. 55-57 (1 April 1970) The following references came to our notice after the completed manuscript had been submitted and typesetting was completed. We are adding them in proof. The references have been integrated in the table and the citations are added with the numbers consecutive to the last number of the original- ly cited ones. 70 BIRKELAND, CHARLES 1974. Interactions between 4 sea pen and seven of its predators. Ecol. Monogr. 44 (2): 211 - 232; 10 text figs. 71 DrLaupenrers, Max WALTER 1927. The red sponges of Monterey Peninsula, California. Ann. Mag. Nat. Hist. (9) 19: 258 - 266 Vol. 21; No. 1 THE VELIGER 72 Ka.xer, H. & Renate Luise SCHMEKEL 1976. Bau und Funktion des Cnidosacks der Aeolidoidea (Gastropoda Nudibranchia). Zoomorphol. 86 (1): 41-60; 7 text figs. 73 Koziorr, Eucene N. 1973. Seashore life of Puget Sound, the Strait of Georgia and the San Juan Archipelago. Univ. Washington Press, Seattle. pp, i-ix + 1 - 283; plts. 1 - 28 74 MacGinitiz, Georce Esper & Nettiz MacGInitTie 1949. Natural history of marine animals. McGraw-Hill Book Co., New York. pp. i-xii + 1-473; ilust. 75 SALVINI-PLAWEN, LUITFRIED VON 1972, | Cnidaria as food-sources for marine invertebrates. Cah. Biol Mar. 13 (3): 385-400; 1 plt. Page 119 Page 120 THE VELIGER Vol. 21; No. 1 Food Preferences, Food Availability and Food Resource Partioning in Two Sympatric Species of Cephalaspidean Opisthobranchs BY DAVID SHONMAN anv JAMES W. NYBAKKEN Moss Landing Marine Laboratories of the Central California State University and Colleges PO. Box. 223, Moss Landing California 95039 (1 Text figure) INTRODUCTION EXTENSIVE STUDIES of the food resources and the feeding habits of cephalaspidean opisthobranchs are uncommon. With the exception of Pane’s (1963, 1965) studies of Chelidonura and Burn & BELL’s (1974a, 1974b) work on 2 species of Retusa, most data concerning cephalaspi- dean feeding habits have been incidentally reported in papers documenting other aspects of their biology. Such reports indicate that cephalaspideans feed on a variety of epifaunal and infaunal organisms. Hurst (1965) re- ported that Philine aperta (Linnaeus) had fed on Forami- nifera and small gastropods and that Scaphander lignan- us (Linnaeus) had ingested Foraminifera, young urchins, tectibranch gastropods, small bivalves and the polychaete Pectinaria. The guts of Cylichna cylindracea (Pennant) and C. magna Lemche were reported by LEMcHE (1956) to contain Foraminifera, as were the guts of Retusa chry- soma Burn and R. pelyx Burn by Burn & BELL (opp. cit.), R. obtusa (Montagu) by Hurst (op. cit.) and R. ovoides (Mil.), R. truncatula (Bruguiére) and R. vari- abilis (Mil.) by Bacescu & Caration (1956). Along with Foraminifera, small gastropods were also recorded among the gut contents of R. truncatula and R. chrysoma. Hurst (op. cit.) and BurN & BELL (1974b) appear to be the only 2 papers reporting observation of foraminiferan ingestion by cephalaspideans. As a result of extensive benthic sampling in Monterey Bay by the Moss Landing Marine Laboratories, a large number of specimens of 2 co-occurring cephalaspidean opisthobranchs, Acteocina culcitella and Cylichna attonsa was available for study. Since these 2 species regularly co- occurred in the same habitats, shared similar anatomical characteristics and, in exploratory dissections, appeared both to feed upon Foraminifera, the present study was undertaken to analyze their food habits and to relate them to food availability. Specifically, we were interested in investigating how 2 such similar species could coexist and how they divided up the food resource. MATERIALS ann METHODS The specimens analyzed in this study were collected from 3 stations in northemn Monterey Bay, California. The sta- tions were designated as follows: Station 1105; lat. 36°51.0°N; long. 121°49.8’W; depth 16.5m; Station 1152: lat. 36°54.8’N; long. 122°01.0'W; depth 36.0m; Station 1177: lat. 36°53.6'N; long. 121°57.5’W; depth 34.5m. The locations are also shown on Figure 1. These stations were sampled at roughly 3-month intervals from August 1971 through November 1972. The specimens were collected with a Smith-McIntyre grab which had a sampling area of 0.1m® (SmirH & Mc- InTYRE, 1954). During the first sampling period (August 1971), 8 replicate samples were taken at each station. During the remaining sampling periods (November 1971, February, May, August, and November 1972), 6 repli- cates were taken at all the stations except 1105. Vol. 21; No. 1 Each grab sample was sieved through 1mm Nytex screens using filtered sea water. The specimens were re- laxed with magnesium chloride (MgCl,) and stained with rose bengal in order to differentiate living from dead specimens. Each sample was preserved in 10% buffered formalin and later transferred to 70% ethanol. Specimens of Acteocina culcitella and Cylichna attonsa were individually dissected to analyze for any food remains in their digestive tracts. Because of the small size of the opisthobranchs, all examinations were performed under a dissecting microscope. Before dissection, all specimens of A. culcitella were measured for greatest shell length. Using an ocular micrometer, Foraminifera obtained from the cephalaspidean digestive tracts were also meas- ured. In order to compare the Foraminifera ingested by the snails with the Foraminifera available in the sediment, the 3 stations were again sampled on 21 May 1974. As before, each station was sampled with the Smith-McIntyre grab using the same procedures described above. In ad- dition, each station was also sampled using a Phleger ae: 122°00’ Santa Cruz i oe Bein Sorted Santa Cruz Point — = THE VELIGER Page 121 corer (3.6cm inner diameter). In the laboratory, each core was kept vertical and then sliced into 1cm sections which were stained with rose bengal and preserved with ethanol. In this way, the vertical distribution of living Foraminifera within the sediment could be determined. Each 1cm subsample was thoroughly dried in an oven (65°C) and the Foraminifera were separated from the sediment by using a solution of bromoform (CHBr,) in which the specific gravity had been adjusted to 2.2 by the addition of methanol. Grsson & WALKER (1967) have shown that, at this density, bromoform is consistently more effective in separating Foraminifera from sediment par- ticles than is carbon tetrachloride. Similar results were reported by SEN Gupta (1971) who recovered 99% of the available Foraminifera with bromoform (diluted with acetone), but only 50 - 85% with carbon tetrachloride. Overlap in food utilization between the 2 species was calculated using indices R,, Ca, derived from information theory as described by Horn (1966). Niche breadth was calculated from formulae of Levins (1968). 121°50" NORTHERN MONTEREY BAY kilometers depth in fathoms Figure 1 , Map of Northern Monterey Bay, California showing location of the three sampling stations Page 122 THE VELIGER Vol. 21; No. 1 Table 1 Number of Food items Recovered from Digestive Tracts of Acteocina culcitella Prey Item 8/71 11/71 2/72 5/72 8/72 11/72 5/74 Total Station 1152 N = 125 Foraminifera Haplophragmoides sp. 4 Trochammina inflata Quinqueloculina sp. Triloculina sp. Miliolid spp. Buccella frigida Elphidiella hannai Elphidium sp. 4 4 2 Globobulimina pacifica Nonionella sp. 1 1 Other Invertebrates 6 4 g No. Snails Examined 10 45 27 13 9 21 125 a onm © £ rv OP © OO Ot — iS) 12 22 24 wm O Ore @ OO i bo _ or — — © wo bo Station 1155 N = 54 Foraminifera Alveolophragmium advena Haplophragmoides sp. 2 Trochammina inflata 3 Quingueloculina sp. 13 8 4 Ss ND eCO, CO PB OP Triloculina sp. Miliolid spp. ] Bucella frigida 23 Elphidiella hannai 7 Elphidium sp. 1 Fissurina sp. 16 _ NO Nontonella sp. 1 Other invertebrates No. Snails Examined 12 28 9 1 4 54 Station 1177 N = 42 Foraminifera Trochammina inflata Quingueloculina sp. Triloculina sp. Miliolid spp. Buccella frigida Elphidiella hannai Elphidium sp. Fissurina sp. Globobulimina pacifica Lagena sp. 1 — Onn fF BO B ine} Com NM OO LO — ~ ie) Nonitonella sp. Other Invertebrates No. Snails Examined 4 11 Or OF WwONnNN —_ Vol. 21; No. 1 RESULTS Food Analysis 1. Acteocina culcitella A total of 221 specimens of Acteocina culcitella (Gould, 1853) were dissected to recover food items from the gut. Of these, 93 (42%) had ingested Foraminifera repre- senting species of the 3 common foraminiferal suborders Miliolina, Rotalina and Textulariina. The results are given in Table 1. Foraminifera were recovered from all portions of the digestive tract, but were primarily found in the crop, gizzard and intestine. Those recovered from the intestine occurred both separately and encased within fecal pellets. Ingested rotaliid and textulariinid tests showed no obvious signs of physical or chemical damage. The tests of miliolid Foraminifera, however, often ap- peared damaged or broken, especially when recovered from the intestine. Miliolids are often described as “por- cellaneous” (CusHMAN, 1969) because their tests have a smooth, shiny appearance which is quite different from the appearance of rotaliid Foraminifera. Broken tests, therefore, could be recognized as “miliolid,” even though they might not be identifiable to genus or species. In most cases, the tests of these damaged Foraminifera re- mained intact as discrete entities, so each could be counted THE VELIGER Page 123 as a separate foraminiferan. These appear here under the heading “unidentified miliolid” or miliolid sp. The foraminiferan most commonly ingested was the rotalid Buccella frigida (Cushman). On several oc- casions (May, 1972, 1974), B. frigida accounted for more than 50% of all the Foraminifera ingested by Acteocina culcitella (Table 1). At other times (November 1971, May 1974) at certain stations, miliolids comprised 40 to 60% of all ingested Foraminifera. Quinqueloculina sp. formed 82% of the undamaged miliolids, while the re- maining 18% were Triloculina sp. Several other species of Foraminifera were recovered, though in relatively small numbers. Of these, Trochammina inflata (Montagu), a textulariinid whose test is composed of agglutinated sedi- ment particles, was the most numerous (Table 2). A small percentage of the items ingested by Acteocina culcitella were not Foraminifera, but were representatives of 3 different invertebrate phyla: Annelida, Arthropoda, and Mollusca. Neither the molluscan shells nor the ostra- cod tests were crushed or broken. 2. Cylichna attonsa Analysis of 456 specimens of Cylichna attonsa (Carpen- ter, 1865) showed that 169 (37.1%) had ingested Foram- inifera. With but 7 exceptions, these Foraminifera were all of the genus Nonionella Cushman. Most were identi- Table 2 Number of Food Items Recovered from Digestive Tracts of Cylichna attonsa Prey Item 8/71 11/71 2/72 5/72 8/72 11/72 5/74 Total Station 1152 N = 219 Foraminifera Nonionella basispinata 3 9 10 9 3 8 Nonionella stella 7 8 7 3 2 6 Nonionella sp. 5 6 7 3 2 3 No. Snails Examined 35 50 36 33 40 25 219 Station 1155 N = 146 Foraminifera Nonionella basispinata 14 18 12 11 4 2 Nonionella stella 1 3 1 2 4 Nonionella sp. 5 3 3 5 2 2 Other Material 3 1 No. Snails Examined 29 40 36 30 3 8 146 Station 1177 N =91 Foraminifera Nonionella basispinata 3 1 9 6 2, 3 Nonionella stella 6 2 8 1 Nonionella sp. 2 1 4 3 4 1 Other Material 1 2 No. Snails Examined 13 7 25 33 8 5 91 Total 456 Page 124 fied as either N. basispinata (Cushman, Moyer) (50%) or as N. stella (Cushman, Moyer) (22%). The remain- ing 23% were too small for specific identification and are listed as Nonionella sp. These data are displayed in Table 2. As with the rotaliids taken from Acteocina culcitella, those taken from Cylichna attonsa showed no obvious signs of chemical or physical damage, even when re- covered from the gizzard or beyond. Of the 7 Foramini- fera which were not Nonionella, 5 specimens were Buc- cella frigida (Cushman) and 2 were Elphidiella hannai (Cushman). Food Availability The abundance and vertical distribution of Foramini- fera collected with the phleger corer were analyzed. These were compared with Foraminifera recovered from the digestive tracts of Acteocina culcitella and Cylichna at- tonsa taken at the same stations 1152, 1155, and 1177. The vertical distribution of living Foraminifera within the top 4cm of sediment at Stations 1152, 1155, and 1177 THE VELIGER Vol. 21; No. 1 on 21 May 1974 is shown in Table 3. In all cases, only the Foraminifera from the top 4m are shown because Foram- inifera decreased markedly below a depth of 4cem and because our initial observations suggested that the 2 mol- lusks could not burrow below 4cm. At stations 1155 and 1177, 97-1% and 93.1%, respectively, of all Foramini- fera occurred within the first 4cm, while at Station 1152, 77.7% are within the top 4cm and 96.1% of all Foramini- fera are found by the 5 centimeter. Within the first 4 cm, no distinct pattern of stratification could be dis- cerned, either in the number of individuals or in species composition. The highest number of Foraminifera oc- curred within the o-1cm increment at Station 1155, the 2-3cm increment at Station 1177 and the 3 -4cm increment at Station 1152. Similarly, the highest number of foraminiferal species occurred within the first cm of substrate at Stations 1155 and 1177, but within the 1 - 2 cm and the 3 - 4cm increments at Station 1152. Certain species occurred at only one level (e. g., Bolivina sp., Globobulimina pacifica and Nonionella fragilis), while others (e. g., Nonionella basispinata and Buliminella ele- gantissima) occurred at all 4 levels. Table 3 Distribution and Abundance of Foraminifera in the Top 4 cm of Substrate at 3 Stations I Sta. 1152 (2 cores) Sta. 1155 (1 core) Sta. 1177 (2 cores) Total Increment (cm) Increment (cm) Increment (cm) Per 4cm Species 1-2 2-3 3-4 1-2 2-3 3-4 1-2 2-3 1152) Sb Haplophragmoides sp. 72 13 0 Textularia sp. 2 1 3 Trochammina inflata 26;14 De 40 8 Pelosina sp. 6 4 5 5 0 20 0 Protcornina sp. 4 2 0 6 0 Quinqueloculina sp. 3532 0;1 1;1 1 4 252 231 8 5 a Buccella frigida 1,0 47 13 22 13 4:6 1 95 10 Bolivina sp. 1 0 1 0 Buliminella elegantissima 8;4 331 2;4 151 15;11 4;10 16 0 48 Elphidella hannai 1;1 itgil 22, 3 3 7;8 8 6 15 Globobulimina sp. ] 0 il 0 Nonionella basispinata 1:1 3:4 Sellil igs} 20 5 11 7 0;1 8;3 29 43 Nonionella fragilis 7:12 3 3 Nonionella globosa 1;1 2;1 0 Nonionella stella Aes Celt py 3 4 2 Teil 9 Total Per cm Core 1 5 40 14 By 96 32 48 27 10 8 27 Core 2 4 37 31 22 15 9 19 X/Core PUB Bese \ PDI G7] Hay) Oc Ha ie 22) Total Per 4cm Core 1] 91 203 51 Core 2 94 54 Vol. 21; No. 1 DISCUSSION The diets of 2 sympatric cephalaspidean opisthobranchs are reported herein for the first time. Both are demon- strated to feed upon Foraminifera. Murray (1973) has suggested that Foraminifera may be ingested by 2 types of feeder, unselective predators who ingest sediment which contains Foraminifera, and selective predators who pref- erentially seek out Foraminifera. Analyses of the food items recovered from the guts of both Cylichna attonsa and Acteocina culcitella suggest that neither can be placed in the category of unselective predators. The 2 species ingest different food items, even though the same food resources are available to both. Cylichna attonsa is extremely stenophagous and feeds only upon foraminiferans of the genus Nonionella. Foram- iniferans of the genus Nonionella comprise from 3.3 to 23.6% of the individuals in the top 4cm of the core samples from the 3 sampling stations, but in no case are they the most abundant foraminiferan in the sample. They are, however, second in abundance rank at Stations 1155 and 1152 and 4" at Station 1177. Cylichna attonsa, there- fore, is a specialist concentrating upon one of the abundant foraminiferan genera. Such extreme stenophagy suggests that the abundance of Nonionella does not vary much over the course of the year. Unfortunately, we lack data on abundance of the foraminiferan fauna for other seasons of the year. Acteocina culcitella, on the other hand, is more of a generalist, feeding upon 13 different species of Foramini- fera as well as taking a few other small invertebrates. If A. culcitella were an unselective predator, it would be ex- pected that the food items in the guts of the cephal- aspidean would be in the same abundance as in the sub- THE VELIGER Page 125 strate samples. A series of Spearman rank correlation tests comparing the abundance of the foraminiferans in the diet with those in the substrate were all insignificant (P > 0.05), indicating that at all 3 stations A. culcitella does not take food in relation to abundance. Hence, this species, although a generalist, is a selective predator. The Foraminifera which were the highest in abundance in the guts of Acteocina culcitella were Buccella frigida and Quinqueloculina sp. In the top 4cm of the substrate at the 3 stations, B. frigida was first in abundance only at Station 1155, whereas at Stations 1152 and 1177, it ranked 11% and 4", respectively. Quinqueloculina sp. ranked 6" in abundance at Station 1152, 8" at Station 1155 and 6" at Station 1177. This is further evidence that A. culcitella does not take prey in relation to its abundance in the substrate. To see whether Acteocina culcitella changed its diet with respect to season, we made tests comparing the rank abundance of prey items in the diet among the sampling dates for the 3 stations. In all cases, there were significant correlations in rank abundance of prey between any 2 sampling dates (Spearman rank test, P < 0.05, all com- parisons). This suggests that either there is no difference in the composition of the prey over season, or that A. culcitella maintains its dietary preference in the face of changing abundances of prey organisms, since the sig- nificant rank correlation values mean that there is a very low probability that the 2 sets of values compared could have come from different populations. Because the 2 opisthobranch species differ markedly in the prey species which they ingest, there is very little overlap in the diets of the 2; hence, the low values of the overlap index shown in Table 4. We conclude, then, that no significant competition occurs between these 2 species with respect to food. Table 4 Overlap Values for Diets of Cylichna attonsa and Acteocina culcitella at 3 Stations and Niche Breadth for Acteocina culcitella Station 1152 Station 1155 Station 1177 = san 1 Date Cy Ry 1/B Cy Ry 1/B Cy Ry 1/B Aug 1971 0 0 4.05 Noy 1971 0.028 0.091 2.01 Feb 1972 0.036 0.095 4.64 0.072 0.249 4.43 May 1972 0 0 2.58 0.019 0.119 2.27 0.245 0.497 2.53 Aug 1972 0.029 0.103 4.04 0.134 0.276 1.92 0.162 0.283 5.11 Nov 1972 0 0 2.78 May 1974 0 0 3.53 0 0 1.93 0 0) 1.34 Page 126 Literature Cited Baczscu, M. « F E. Caraion 1956. Animale mincatoare de foraminifere. P Rom. 6 (4): 551-553 Burn, Rosert « K. N. Bett 1974a. Description of Retusa chrysoma Burn sp. nov. (Opisthobranchia) and its food resources from Corner Inlet, Victoria. Mem. S. Nat. Mus. Vict. 35: 115-119 1974b. Description of Retusa pelyx Burn sp. nov. (Opisthobranchia) and its food resources from Swan Bay, Victoria. Journ. Malacol. Soc. Austral. 3 (1): 37-42 CusHman, J. A. Commun, Acad. Rep. 1969. Foraminifera. Harvard Univ. Press, Cambridge, Mass. 605 pp. Gisson, T. G. W. M. Waker 1967. Flotation methods for obtaining foraminifera from sediment sam- ples. Journ. Paleontol. 41 (5): 1294 - 1297 Horn, Henry S. 1966, Measurement of “overlap” in comparative ecological studies. Amer. Natural. 100: 419 - 424 THE VELIGER Vol. 21; No. 1 Hurst, ANNE 1965. Studies on the structure and function of the feeding apparatus of Philine aperta with a comparative consideration of some other opistho- branchs. Malacologia 2: 221 - 347 LEMCHE, HENNING 1956. The anatomy and histology of Cylichna (Gastropoda Tectibranchia). Spolia Zool. Musei Hauniensis 16: 1 - 278 Levins, RicHARD 1968. Evolution in changing environments. Princeton, 120 pp. Pang, Ropert TREAT 1963. Food recognition and predation on opisthobranchs by Navanax inermis (Gastropoda : Opisthobranchia). The Veliger 6 (1): 1-9; plt. 1; 1 text fig. (1 July 1963) 1965. Natural history, limiting factors, and energetics of the opistho- branch Navanax inermis. Ecology 46 (5): 603-619; 9 text figs. SmitH, W. « A. D. McINtyRE 1954. A spring-loaded bottom sampler. U. K. 38 (1): 257 - 264 Princeton Univ. Press, Journ. Mar. Biol. Assoc. Vol. 21; No. 1 THE VELIGER Page 127 Checklist of Marine Mollusks at Coyote Point Park, San Francisco Bay, California MARY K. WICKSTEN Allan Hancock Foundation, University of Southern California, University Park, Los Angeles, California 90007 (1 Text figure) INTRODUCTION Coyote PoInT Is LocaTED in the city of San Mateo on the western shore of San Francisco Bay, California. With- in its boundaries are 4 marine habitats: salt marsh, pilings and floating docks, rocky rubble and boulders, and sandy beach (Figure 1). The harbor on the east side of the point has been created by extensive dredging and filling. Although the park offers one of the southernmost ex- tensive rocky intertidal habitats in San Francisco Bay, it has been studied poorly. Packarp (1918) mentioned species taken in oyster beds near Point San Mateo. Rec- ords of introduced species at the park are given by SToH- LER (1962), Hanna (1966), CarLtTon (1969), and WIcKSTEN (1976). There are no quantitative data for any of the marine mollusks despite their abundance, impor- tance in the local food chain, and use in a sport fishery. From 1970 to 1977, I maintained a list of marine mol- lusks at the park. Notes on their natural history and sea- sonal occurrence also were kept. This paper presents this information in hopes that it will stimulate research in this unusual protected area and assist workers in deter- mining the distribution of mollusks in San Francisco Bay. METHODS During 1970 to 1977, collecting trips were made at least once in each season of the year. All areas were sampled from the highest tidal zone to the —2.0 foot [-0.6m] tide level except at the mud flats, where extreme softness of the mud prevented exploration below the +1.0 foot [0.3m] tide level. Animals also were collected by means of SCUBA diving and snorkeling off Peninsula Beach and in the harbor at depths to 5m. The dredge tailings near the harbor were examined for empty shells. Specimens of all species are available for inspection in the collections of the Coyote Point Museum or in my personal collection. Additional specimens were donated to the California Academy of Sciences in San Francisco. The list of species is arranged in phylogenetic order. A species is termed resident (R) if it has been taken during all seasons of the year for 3 or more continuous years. Casual species (C) are natives found only once or twice during the period of study. Accidental species (AC) are introduced species found alive only once during 1970 to 1977, or which have been reported alive at the park since 1960. Those species termed offshore (O) have been found cast ashore after storms or strong waves during at least 3 consecutive years, but have not been observed by me in the intertidal zone. Except for Tegula funebralis, all the species known only from dead shells were obtained in the dredge tailings. Native species (N) are those whose place of origin is the west coast of North America. I follow the report of CarRLTON (1975) in determining which species have been introduced from the Atlantic Ocean (A) or the area around Japan and Korea (J). RESULTS Of the 36 species found at Coyote Point, 20 (56%) are native, 14 (39%) have been introduced from the At- lantic Ocean, and 2 (5%) have been introduced from the western Pacific Ocean. The Atlantic species probably were brought in with eastern oysters (Crassostrea virgini- ca) which were farmed near Coyote Point until about 1920 (BarRETT, 1963). The pyramidellid snail Odostomia sp. belongs to a group in which identification to species is difficult. Until Page 128 THE VELIGER Vol. 21; No. 1 San Francisco Bay M1 vZ = Salt Marsh Pegg ane. Figure 1 Map of Coyote Point the species can be determined, its place of origin remains uncertain. A flat slipper shell, Crepidula perforans (?) occurs only in apertures of large gastropod shells occupied by the hermit crab Pagurus hirsutiusculus Dana, 1851. Unlike Crepidula nummaria, this slipper shell lacks a shaggy periostracum and a deep shell. Although the Atlantic slip- per shell Crepidula plana Say, 1822 may have been intro- duced into San Francisco Bay, I can detect no morpho- logical differences between flat slipper shells from Coyote Point and shells taken from apertures of hermit crab- inhabited shells collected at Pacific Grove, off Santa Cata- lina Island, and along the Palos Verdes Peninsula, Cali- fornia. Until some means is found to distinguish C. per- forans from C. plana in areas where the two might mingle, the identity of the flat slipper shell at Coyote Point re- mains uncertain. Although 15 species of resident mollusks occur at Coy- ote Point, only 9 species were observed spawning or found as recently-settled individuals Ilyanassa obsoleta, Urosal- pinx cinerea, and Busycotypus were observed laying egg masses during all seasons of the year. Two Aplysia califor- nica produced egg masses in July, 1977. Egg-bearing Crepidula convexa and spawning Mytilus edulis were found during all seasons of the year. Very small, newly settled Mytilus edulis, Tapes japonica, and Mya arenaria were collected during summer months. The turbid water of San Francisco Bay contains much plankton and detritus which can be used as food by the suspension feeders and deposit feeders at Coyote Point. Abundant growths of diatoms, Ulva sp., and other algae nourish the herbivores. Urosalpinx cinerea eats Ostrea lurida, and may prey on barnacles at the point. Busyco- typus canaliculatus and Ilyanassa obsoleta readily will feed on dead fish. There are few predators on mollusks at Coyote Point. No echinoderms were found during the period of study. Except for Urosalpinx cinerea, no carnivorous gastropod has been observed preying on other mollusks. The rock crabs, Cancer productus Randall, 1839 and C. antennari- Vol. 21; No. 1 THE VELIGER Page 129 Table 1 Species List Species Residency Origin AMPHINEURA: Mopalia hindsti (Reeve, 1847) C N PELECYPODA: Mytilus edulis Linnaeus, 1759 R N Musculus senhousia (Benson, 1842) O J Ischadium demissum (Dillwyn, 1817) AC? A Ostrea lurida Carpenter, 1863 R N Epilucina californica (Conrad, 1837) C N Tapes japonica Deshayes, 1853 R J Mercenaria mercenaria (Linnaeus, 1758) AC A Gemma gemma (Totten, 1834) R A Cryptomya californica (Conrad, 1837) € N Mya arenaria Linnaeus, 1758 R A Macoma balthica Linnaeus, 1758 R A Macoma nasuta (Conrad, 1837) R N Lyonsia californica Conrad, 1837 O N GASTROPODA: Collisella digitalis (Rathke, 1833) R N Collisella strigatella (Carpenter, 1864) R N Collisella pelta (Rathke, 1833) € N Littorina scutulata Gould, 1849 R N Crepidula convexa Say, 1822 R A Crepidula nummaria Gould, 1846 C N Crepidula perforans Valenciennes, 1846(?) R N? Nucella lamellosa (Gmelin, 1792) C N Urosalpinx cinerea Say, 1822 R A Busycotypus canaliculatus (Linnaeus, 1758) O A Ilyanassa obsoleta (Say, 1822) R A Phytia myosotis (Draparnaud, 1801) R A Aplysia californica Cooper, 1863 C N Notes 2 animals found by bluffs, 6 April 1977. On rocks, docks, and pilings. Probably lives on soft bottom. Edge of salt marsh, 1975 (M. Danielson, pers. comm.) On rocks, docks, and pilings. 2 animals cast ashore, 22 April 1973. In sand and mud. Collected in 1968 (Carlton, 1969). In sand and mud. 1 animal commensal with Arenicola brasiliensis Nonato, 1958; August 1973. In sand and mud. In mud. In mud. Probably lives in soft bottom. On boulders at high tide. On boulders in middle intertidal zone. 1 animal found on boulders, 2 January 1974 and 1 found on boulder, 2 July 1977. On rocks at high tide level. On shells and cobble, low tide level. 1 animal found on rock at low tide, 1972. Inside shells occupied by hermit crabs. 3 animals under ledge, 25 March 1972. Among Ostrea lurida and on rocks. Rarely found intertidally on sand or mud, more common on soft subtidal bottoms. On mud flats and in salt marsh. Under drift at high tide in salt marsh. 3 large animals found near rocks by bluffs, 2 July 1977. us Stimpson, 1856 probably eat some pelecypods. The black-tailed shrimp Crangon nigricauda Stimpson, 1856 eats Gemma gemma. The bat ray Myliobatus californica Gill, 1865 and the leopard shark Triakis semifasciata Girard, 1859 eat pelecypods inhabiting shallow sandy or muddy bottoms off the park. DISCUSSION Fluctuating conditions of temperature, salinity, and tur- bidity at Coyote Point may prevent many species of mollusks from becoming residents. Casual species which occur widely on the coast outside of San Francisco Bay may drift in as planktonic larvae or be recruited from other parts of the Bay when environmental conditions are favorable for their survival. Of the 2 accidental species, Mercenaria mercenana probably no longer occurs at Coyote Point. No live speci- mens have been found since 1968 (CarLTon, 1969), and no living populations are known near San Mateo. Ischa- dium demissum, however, is widespread in southern San Francisco Bay and may extend its range into the salt marsh at the park. Except for Tegula funebralis, all the species known only from dead shells are inhabitants of sandy or muddy bot- Page 130 Table 2 Species Known Only from Dead Shells PELECYPODA: Anadara transversa (Say, 1822) Argopecten irradians trradians (Lamarck, 1819) Crassostrea virginica (Gmelin, 1791) Clinocardium nuttalli (Conrad, 1837) Tresus nuttalli (Conrad, 1837) Petricola pholadiformis Lamarck, 1818 Barnea subtruncata (Sowerby, 1834) GASTROPODA: Tegula funebralis (A. Adams, 1855) Odostomia sp. Zip Zo LZ >>> A toms. Tegula funebralis is abundant outside the Bay and near its mouth, which suggests that it may be a casual visitor to rocky areas at the park. Only old, chalky valves of Clinocardium nuttalli and Barnea subtruncata were found in dredge tailings. How- ever, entire shells of Tresus nuttalli were discovered buried with the gaping posterior end oriented toward the surface of the mud. PacKarp (1918) reported finding shells of T. nuttalli (as Schizothaerus nuttalli) and live individuals of C. nuttalli (as Cardium corbis) in southern San Francisco Bay. That these shells were found only in dredge tailings which also contain shells of Crassostrea virginica suggests that these native species occurred near the point in the THE VELIGER Vol. 21; No. 1 early part of the twentieth century. It is possible that these pelecypods were killed by dredging that buried them. ACKNOWLEDGMENTS I thank James T: Carlton, University of California, Davis; and Don Cadien, Marine Biological Consultants, for as- sisting in the identification of some of the mollusks. Mary- ann Danielson, Coyote Point Museum, provided informa- tion on Ischadium demissum and allowed use of the facilities at the museum. Literature Cited Barrett, Exmvors M. 1963. The California oyster industry. Fish Bull. 128: 103 pp.; $2 text figs. Car.Ton, James THEODORE 1969. Léttorina littorea in California (San Francisco and Trinidad Bays). The Veliger 11 (3): 283 - 284 (1 January 1969) 1975. Introduced intertidal invertebrates. In: Ralph I. Smith & James T. Carlton (eds.), Intertidal invertebrates of the central Califor- nia coast: 17-25 Univ. Calif, Press, Berkeley, 3rd ed.: i- xviii +716 pp.; 156 pits. Hanna, G Darras 1966. Introduced mollusks of western North America. Occas. Pap. Calif. Acad. Sci. 48: 1-108; pits. 1-4; 85 text figs. (16 February 1966) Univ. Calif Publ. (12 September 1918) Calif. Dept. Fish & Game, Pacxarp, Eart L. 1918. Molluscan fauna from San Franeisco Bay. Zool. 14 (2): 199-452; plts. 14-60 Stouier, RuDOLF 1962. Busycotypus (B.) canaliculatus in San Francisco Bay. The Veliger 4 (4): 211-212; 1 text fig. (1 Apmil 1962) WicxsTen, Mary KaTHeRIng 1976. Argopecten irradians in San Francisco Bay, California. The Veliger 18 (4): 418 (1 April 1976) Vol. 21; No. 1 THE VELIGER Page 131 Infection of Ostrea lurida and Mytilus edults by the Parasitic Copepod Mytilicola orientalis in San Francisco Bay, California WILLIAM BRADLEY anp A. E. SIEBERT, Jr. Department of Zoology, University of California, Berkeley, California 94720 INTRODUCTION Mytilicola orientalis is an endoparasitic copepod which infects the intestine and rectum of several bivalve species. Originally described from Mytilus crassitesta and Crass- ostrea gigas collected in the Inland Sea of Japan (Mor, 1935), it has been introduced to the Pacific coast of Canada and the United States, probably with the im- portation of Japanese C. gigas. Distribution is sporadic and limited to the immediate vicinity where infested oyster stock has been introduced (BERNARD, 1969). The parasite has been found in Washington waters in Ostrea lurida, C. gigas, Mytilus edulis, Paphia (= Protothaca) staminea, and Crepidula fornicata (Opiauc, 1946). Cuew et al. (1964a) recorded infestation of O. lurida, M. edulis, and M. californianus from Humboldt Bay, California, and KaTKANnsky et al. (1967) reported C. gigas infections in Yaquina Bay, Oregon. There are no previous studies dealing with Mytiltcola orientalis infec- tion of bivalves from the central California coast, particu- larly San Francisco Bay. In British Columbia, Mytilicola orientalis has a single reproductive period from June to late August (BERNARD, 196g), while in California and Oregon there is continu- ous reproductive activity, although the numbers of fe- males carrying egg sacs decrease during the winter (CHEW et al., 1964b). SparKs (1962) indicated that reproductive activity in Washington waters occurred only in fall and spring. Sparks also found peaks of Crassostrea gigas in- fection in the spring and fall, followed by rapid declines in infection rates. KATKANSKY et al. (1967) observed that the incidence and intensity of the copepod infec- tions in Ostrea lurida did not vary significantly during the year and that there were no short-term cyclic occur- rences of these parameters. There has been no previous work relating incidence or intensity, or both, of Mytilicola infections to host size. In this study, Ostrea lurida and Mytilus edulis from San Francisco Bay were examined for the presence of Mytilicola orientalis. Rates of infestation were deter- mined, as were seasonal fluctuations of mussel infections and copepod reproduction. METHODS The samples of both Ostrea lurida and Mytilus edults were taken from an intertidal strip of rocky landfill at the Berkeley Marina, Berkeley, California. The oyster population was scattered in the much more dense popu- lation of mussels which covers nearly all the hard substrate present in the area. Between June, 1975 and June, 1976, 30 O. lurida were randomly sampled on a monthly basis, with the exception of 4 months when slightly fewer were taken. Mussels were sampled quarterly, commencing in the fall of 1975. These samples contained a minimum of 70 individuals. All samples of both bivalve species were taken from a similar tidal height (approximately the +0.3m level) to minimize variability in exposure to infection. Before dissection, mussel lengths were measured to the nearest millimeter. Oyster lengths were not recorded, due to the great variability in the shape of oyster shells. Be- cause of this variability, the length of the Ostrea lurida shell does not correlate either to size or weight of the oyster meat. All animals were examined under a dissect- ing microscope while fresh. The entire gut was opened and all Mytilicola orientalis removed and examined for visible egg cases. The incidence of infection is defined as the percent of the sample infected with M. orentalts while intensity of infection refers to the average number of parasites per infected host in the sample. There were 2 size classes of M. orientalis present in the bivalves, as noted by CHEw et al. (1964a), larger females 6 - 11mm Page 132 in length, and males and immature females 2.5mm in length. RESULTS The parasitic copepod Mytilicola orientalis was found in both Ostrea lurida and Mytilus edulis in San Francisco Bay. The incidence of infection was much greater in the Table 1 Incidence and intensity of Mytilicola orientalis infections in Mytilus edulis (quarterly samples) and Ostrea lurida (quarterly totals of monthly samples). THE VELIGER Vol. 21; No. 1 mussels at the study site, although ample oyster hosts were available. The rates of infection are compared in Table 1. Due to the low incidence of infection in O. luri- da, we were unable to quantitatively examine the effect of the infection on either the host or the parasite. Several aspects of the host-parasite relationship were investigated in the Mytilus edulis sampled. We found that in 3 of the 4 samples there was no correlation be- tween the size of the host and the intensity of the infec- tion. The single exception, that of the winter sample, indicated that larger M. edulis harbored fewer parasites per infected host (P < 0.005, using a linear regression analysis) . Of the data in Table 2, only the summer sample showed significant (P < 0.005) variation between the number of observed and expected infections of mussels, the smallest mussels being less infected than expected and the larger ones having higher than expected incidence. Intensit # individuals Incidence (#/intected Table 2 indicates that throughout the year the highest in samples (%) animal) rate of infection is present in medium-sized animals. ARSED Seasonal fluctuation of the incidence of infection was not fall 101 40.6 21 significant in comparisons between any 2 seasonal sam- winter 101 48.5 3.3 ples, and the intensity of infection was not notably varied spring 70 37.1 2.6 (Table I). summer 95 36.8 Be The Arcsin Conversion Test (SoKAL & Ror, 1969) Ostrea lurida was used to detect seasonal variation in Mytilicola orient- fall o Oo 0.0 alis reproductive activity. Females with egg sacs were Maran Sh oe oe found throughout the year at the study site, evidence that spring 103 1.0 2.0 ’ summer 75 2.7 2.0 Table 2 Incidence of Mytilicola orientalis infection in Mytilus edulis by size class. Numbers of observed infections are by actual count. The numbers of expected infections were calculated according to the method of Sokal and Rolf (1969). Size Class Infected Non-infected Mytilus edulis %o Observed Expected Yo Observed Expected length in cm 0.0-2.5 fall 31 5 69 11 10 winter 23 5 11 77 17 1] spring 29 2 3 71 5 4 summer 12 3 9 88 21 13 2.6-4.5 fall 51 26 20 49 25 31 winter 57 39 34 43 29 34 spring 43 22 19 57 29 32 summer 45 20 7 55 24 15 4.6-8.0 fall 29 10 14 71 24 20 winter 45 5 6 55 6 6 spring 18 2 4 82 9 7 summer 44 12 4 56 15 9 =x. Vol. 21; No. 1 the copepod reproduces continuously there. There was significant seasonal fluctuation in the occurrence of fe- males carrying egg cases. The summer sample contained the greatest percentage of gravid females (31.8%), while the fall value of 5.9% was significantly lower (P < 0.005). There was significant (P < 0.05) difference between the winter value of 17.5% and the fall value. The difference between the winter and spring values was not significant, nor was that between the spring and summer, though the difference between the winter and summer values was significant (P < 0.05) (Table 3). Table 3 Myuticola orientalis reproductivity in Mytilus edulis. THE VELIGER male/immature female female with % M. orientalis without eggs eggs with eggs fall 32 48 5 5.9 winter 99 33 28 17.5 spring 46 9 16 22.5 summer 45 13 27 31.8 DISCUSSION The occurrence of Mytilicola orientalis in Ostrea lurida and Mytilus edulis is not surprising, as they were probab- ly introduced when Crassostrea gigas was imported from Japan and cultured in south San Francisco Bay by the Consolidated Oyster Co. in the 1930’s. The present study site at the Berkeley Marina is approx- imately 24km from the area where Consolidated Oyster Co. maintained its beds, indicating that Mytilicola ori- entalts has probably spread throughout San Francisco Bay in the last 40 years. There are no other reports on the presence of the copepod in San Francisco Bay bivalves, but a widespread distribution is likely. The fact that My- tilus edulis infections are more common than those in Ostrea lurida agrees with the reports of OpLauc (1946) and Cuew et al. (1964b). Odlaug reported infections in O. lurida ranging from 1.0% to 9.2% and between 42.5% and 73.6% for M. edulis from Puget Sound. Chew et al. reported a 9.6% O. lurida infection rate and a 58.3 7o rate for M. edulis collected in Humboldt Bay, Cali- fornia. Since the O. lurida appeared to be randomly Page 133 mixed with and at the same tidal height as the M. edulis at our study site, the large difference in M. orientalis incidence might indicate a preferential infection of M. edulis by the copepod. HEprer (1955) found that Mytz- licola intestinalis is able to infect Ostrea edulis when the oysters are exposed to copepodites, but when O. edulis and M. edulis are both exposed to the infective stage in the same aquarium, the mussels are readily infected and oysters are not. CHENG (1967) also noted that it would appear that M. intestinalis demonstrated a preference for M. edulis, but if the mussel was not available for M. in- testinalis copepodites to infect, they would parasitize O. edulis instead. Since only one of our 4 Mytilus edulis samples showed a correlation between host size and intensity of infection, the present results disagree with those of GRAINGER (1961) and Davey & Gre (1976) for Mytilicola intestinalis, al- though BotsTEr (1954) found that differences in intensity of M. intestinalis infections may be slight, if there are any at all. At present, it is not possible to reconcile these reported differences. The incidence of Mytilicola orientalis infections does not seem to occur more readily among a particular size class or classes of Mytilus edulis. As noted above, sig- nificant variation was found only in the mussels taken in the summer. This sample was taken in late summer and small mussels less than 2.5cm in length were only a few months old (GraINncER, 1961). The rapid growth of young mussels may have allowed the young mussels to reach several centimeters in length in a time sufficiently short such that infections are not estab- lished. Lack of significant seasonal fluctuation in inci- dence or intensity of infection in the M. edulis popula- tion studied agrees with the data of KaTKANSky ef al. (1967), though seasonal fluctuation within a given size class is possible. The presence of gravid female Mytilicola orientalts throughout the year, with a peak of activity in the sum- mer, concurs with the report of Cuew et al. (1964b) for California and Oregon, rather than with BERNARD (1969) for British Columbia. The decrease of females carrying egg cases in the fall and the return to a higher winter value are unlike previous reports and were unex- pected in view of the report by BotsTER (1954) who indicated that low water temperatures reduced breeding efficiency in M. orientalis. The year-round reproductive activity of M. orientalis may be a result of hydrographic conditions in San Francisco Bay, but similar data are not available from other geographic regions with which to directly compare our data, Page 134 THE VELIGER Vol. 21; No. 1 Literature Cited Bgrnarp, Franx R. 1969. The parasitic copepod Mytilicola ortentalis in British Columbia bivalves. Journ. Fish. Res. Brd. Canada 26: 190-191 Boxster, G. C. 1954. The biology and dispersal of Mytilicola intestinalis Steuer, a copepod parasite of mussels. Fish. Investig. London (2) 18: 1-30 Cxreneo, THomas CLEMANT 1967. Marine molluscs as hosts for symbioses with a review of known parasites of commercially important species Jn Adv. in Marine Biol. 5: i - xiii + 424 pp.: 223 figs.; New York, N.Y. (Academic Press) Cuew, K. K., A. K. Sparxs « S. C. KaTansxy 19642. First record of Mytilicola orientalis Mori in the California mus- sel Mytilus californtanus Conrad. Journ. Fish. Res. Brd. Canada a1: 205 - 207 Cuew, K. K., A. K. Spars, S. C. Katansxy « D. HucHes 1964b. Preliminary observations on the seasonal size distribution of Mytilicola orientalis Mori in the Pacific oyster Crassostrea gigas (Thun- berg) at Humboldt Bay, California, and Yaquina Bay, Oregon. Proc. Nat. Shellfish Assoc. 55: 1 - 8 Davey, J. T.« J. M. Gee 1976. The occurrence of Myttlicola intestinalis Steuer, an intestinal copepod parasite of Mytilus, in the South-west of England. Journ. Mar. Biol. Assoc. U. K. 56: 85 - 94 Grainogr, J. N. R. 1961. Notes on the biology of the copepod Mytilicola intestinalis Steu- er. Parasitology 41: 135 - 142 Hepper, B. T. 1955. Environmental factors governing the infection of mussels by My- tilicola intestinalis. Fish. Invest. London (2) 20: 1 - 213 Katxansky, S. C., A. K. Sparxs a K. K. Coew 1967. Distribution and effects of the endoparasitic copepod, Mytili- cola orientalis, on the Pacific oyster, Crassostrea gigas, on the Pacific coast. Proc. Nat. Shelfish Assoc. 57: 50-58 Mori, T. 1935. Mytilicola orientalis, a new species of parasitic copepod. Dobuts. Zasshi. 47: 687 - 689 Opravuse, T. C. y 1946. The effect of the copepod, Mytilicola orientalis, upon the Olym- pian oyster, Ostrea lurida. Trans. Amer. Microscop. Soc. 68: 311 - 917 Soxat, R. R. « F J. Rorr 1969. Biometry. W. H. Freeman & Co., San Francisco. 776 pp. Sparks, A. K. 1962. Metaplasia of the gut of the oyster Crassostrea gigas (Thun- berg) caused by infection with the copepod Mytilicola orientalis Mori. Journ. Insect Pathol. 4: 57 - 62 Vol. 21; No. 1 THE VELIGER Page 135 Aestivating Giant African Snail Population in South Andaman During 1973, 1974, and 1975 G.P.GUPTA, S. S. S. GAUTAM, S. R. ABBAS IARI, Regional Research Station, Port Blair PD. SRIVASTAVA Division of Entomology, Indian Agricultural Research Institute, New Delhi — 110012, India Achatina fulica Bowdich, 1882 is a serious land snail pest of a number of vegetables, fruits, plantation crops, and omamentals. During unfavourable weather conditions they undergo aestivation and on the return of favourable conditions they resume activity. The present work relates to the aestivating snail population. Work on such studies was initiated in 196g in certain villages of South Andaman and the municipal area of Port Blair. An account of the aestivating giant African snail population during 1973 in 11 villages of South Andaman already has been pub- lished (ApBAs & GAUTAM, 1975). The present paper gives a comparative account of the aestivating snail populations in these villages during the summer seasons (January to April) of 1973, 1974 and 1975 (Table 1). The present studies indicate that the position of 6 vill- ages, namely Makkapahar, Calicut, Brishganj, Garachar- ma, Pahargaon and Dollyganj remained unchanged dur- ing these 3 years, while in the case of the other 5 villages there was a slight change. However, the trend in all the villages in all 3 years was of a decline of aestivating snail populations. At Makkapahar the aestivating snail popu- lation throughout these 3 years continued to remain high- est, varying from 102.39 to 86.81 /m’, followed by Calicut, varying from 86.40 to 65.99/m*. The villages nearer to the town of Port Blair had comparatively much lower snail populations (7. e., Dolliganj, Nayagaon, Shadipur, Schoolline and Pahargaon); these 5 villages are only about 5 - 8 km from Port Blair, whereas Makkapahar and Calicut which stand I and II, respectively, are about 20 and 14 km distant. A similar trend was observed by ABBAS « Gautam in their 1973 studies on the aestivating giant African snail population in these 11 villages. This trend now stands confirmed as a result of 3 years’ continuous observations in these 11 villages. SUMMARY A comparative study of the aestivating population of the giant African snail in 11 villages of South Andaman was done during 1973, 1974 and 1975. The highest average population per square metre was found to be 102.39, 98.54 and 86.81 respectively in 1973; 1974 and 1975 whereas the lowest population per square metre in the same years was found to be 20.10, 17.11 and 14.57 respectively. It was observed that the population declined from year to year in all 11 villages. Villages nearer to Port Blair had the lowest population, whereas those farther away had the highest. ACKNOWLEDGMENT The authors are grateful to Dr. N. C. Pant for taking a keen interest in the progress of this work. Literature Cited Azsas, S. R. « S. S. Stinon Gautam 1975- Population of Achatina fulica Bowdich, 1882 in aestivating pock- ets in South Andaman. The Veliger 17 (3): 311-912 (1 January 1975) Page 136 THE VELIGER Vol. 21; No. 1 Table 1 Aestivating Giant African Snail Population in South Andamans in 1973, 1974 and 1975 Sl. Average population of snail/m? No. Locality Data on aestivating pockets and position of population Remarks 1973 1974 1975 1973 1974 1975 1. Schoolline A. 34 A. 50 A. 143 26.21/VIII 22.68/VIII =: 18.35/1X B. 92.64 B. 74.13 B. 200.10 C. 2429 C. 1682 C. 3672 Ze Pahargaon A. 68 A. 67 A. 226 31.61/VII =. 27.73/VII 26.59/VII Position unchanged B. 120.53 B. 104.49 B. 233.17 C. 3810 C. 2898 C. 6202 33 Austinabad EO? i, 19) A. 207 52.14/1V 43.59/11 32.92/1V B. 106.76 B. 54.39 B. 268.55 C. 5567 C. 2371 C. 8845 4. Prothrapur is, 08) A. 53 A. 148 53.79/11 42.07/1V 37.71/11 B. 93.76 B. 44.61 B. 161.80 C. 5044 C. 1877 C. 6115 8), Brischgan] IX 1K0) eX, ih A. 115 50.79/V 39.92/V 30.19/V Position unchanged B. 99.99 B. 42.91 B. 115.37 C. 5079 C. 1713 C. 3483 6. Garacharama IX, 1/8) bs U2 A. 308 34.55/VI_ | 29.98/VI 28.11/VI Position unchanged Be 9 1e53 B. 71.46 B. 259.28 C. 3163 C. 2143 C. 7289 Us Calicut A. 103 A. 130 A. 535 86.40/II 79.16/11 65.99/I1 Position unchanged B. 119.97 B. 73.49 B. 340.23 C. 10366 C. 5818 C. 22452 8. Dollyganj IX, ay A. 41 A. 64 20.10/XI 17.11/XI1 14.57/XI Position unchanged B. 73.69 B. 40.25 B. 57.16 C. 1482 C. 689 C. 833 9. Makkapahar Avro Iss NOP A. 536 102.39/1 98.54/1 86.81/1 Position unchanged B. 99.80 B. 58.90 B. 438.77 C. 10219 C. 5804 C. 38093 10. Shadipur Js, BY J, BY A. 240 25.06/X 22.15/1X 19.81/V III B. 84.93 B. 52.90 B. 309.52 C. 2129 C. 1156 C. 6134 11. Nayagaon A. 60 A. 49 A. 169 25.61/1X 20.64/X 17.45/X B. 85.49 B. 50.53 B. 160.53 C. 2181 C. 1043 C. 2802 ‘est A. = Number of aestivating pockets. B. = Area of aestivating pockets. C. = Number of aestivating Snails. Vol. 21; No. 1 THE VELIGER Page 137 Temporal Changes in a Tropical Rocky Shore Snail Community TOM M. SPIGHT Woodward-Clyde Consultants, 3 Embarcadero Center, Suite 700, San Francisco, California 94111 (1 Text figure) INTRODUCTION More SPECIES ARE GENERALLY found in tropical commu- nities than in comparable temperate communities, and rocky shore gastropod assemblages are no exception. On Pacific Ocean rocky shores, the same collecting effort will yield about 2.4 times as many species in Costa Rica as in Oregon (Miiuer, 1974). Rocky shores contain the same range of habitats at both latitudes (SpicHT, 1977). If the average tropical snail uses fewer habitats than a typical temperate one, the tropical species would be more specialized, but overlap among species could be about the same as in temperate waters. Alternatively, tropical snails can utilize the same range of habitats as their tem- perate counterparts; when this is the case, overlap among species will be much greater than in temperate communi- ties. To determine whether tropical snails use fewer habi- tat types than temperate ones do, I collected snails from a number of quadrats at Playas del Cocos, in northwestern Costa Rica during 1970 (SpicHT, 1976). Each quadrat was characterized by its shore level, substrate, and degree of wave exposure. Using these variables, habitat descrip- tions were constructed for all species. Most Costa Rican snails use fewer of these habitat types than do typical snails from Washington State (1.¢., they are more spe- cialized; SpicHT, 1977). Habitat descriptions tell where snails were found, but not how often they were found where they were supposed to be. Tropical snails were found less often on patches of “suitable habitat” (places included in their habitat de- scription) than temperate ones were (SPIGHT, 1977). Many of these “absences” may have been observed because habi- tat descriptions were not precise enough (e. g., the inves- tigator did not recognize as many habitat types as the snails do). On the other hand, tropical snails may simply be less predictable than temperate ones. One can assess predictability by observing how distri- butions change over time. To assess year-to-year distri- butional changes, I returned to Playas del Coco in 1971 and resampled 2 quadrats I had examined during 1970. Two questions were asked: iz) are the assemblages at one place similar in successive years, and 2) can year- to-year changes at one place be accounted for by growth of residents and recruitment of juveniles? The discussion will examine the results in terms of habitat selection and other factors causing distributional patterns. METHODS The quadrats are more or less uniform areas of rock reef, sufficiently differentiated from the surrounding areas to be readily recognized without artificial markers. The quadrat exposed to moderate wave action (Q-11) is a flat 6m? portion of a highly dissected rock face on the north side of Punta Miga (height, 0.67m above mean low water [MLLW]). The calm-water quadrat (Q-8) is a 3m* area on the extreme southern portion of Bahia El Coco (height 1.4m above MLLW). It is protected from oceanic conditions by Punta Miga. Most of the reef near Q-8 is buried by silty sand, but the reef is continuously exposed about 1m further along the beach (see SpicHrT, 1976, for maps showing quadrat locations and for further sampling details). On each visit (8 February - 21 March, 1970; 7-14 February, 1971), all gastropods were handpicked from the quadrats. The snails were sorted to species, and all those larger than 6mm were measured with vernier cali- pers. Individuals that could be readily identified were re- Page 138 THE VELIGER Vol. 21; No. 1 re ee eee Table 1 Comparison of gastropod assemblages found in different years on two rocky-shore quadrats at Playas del Coco, Costa Rica. Collection of 1970 Collection of 1971 Species Shell length (mm) No | Shell length (mm) Quadrat with moderate wave action (Q-11) Acanthina brevidentata (Wood, 1828) Thais melones (Duclos, 1832) Fissurella virescens Sowerby, 1835 Siphonarnia maura Sowerby, 1835 Fissurella longifissa Sowerby, 1863 Opeatostoma pseudodon (Burrow, 1815) Anachis lentiginosa (Hinds, 1844) Thais speciosa (Valenciennes, 1832) Siphonaria gigas Sowerby, 1825 Scurna stipulata (Reeve, 1855) Quadrat in calm-water area (Q-8) Acanthina brevidentata (Wood, 1828) 188 6-26 Anachis costellata (Broderip and Sowerby, 1829) 246 5-18 Anachts lentiginosa (Hinds, 1844) 693 3-6 Anachis rugulosa (Sowerby, 1844) 1333 3-6 Nerita funiculata Menke, 1851 92 3-13 Thais biserialis (Blainville, 1832) 53 4-24 Fossarius sp. 123 3-5 Anachis pygmaea (Sowerby, 1832) 6 6 Notoacmea biradiata (Reeve, 1855) 83 6-11 Purpura pansa Gould, 1853 1 32 Range Mean SD Range Mean SD 9.9 1.94 252 \ 6-24 17.0 4.16 13.6 2.71 105 6-19 13.4 3.71 = — 127 — — — — — 134 — — eS 2.20 45 3-12 8.4 2.24 12.3 4.87 76 5-38 13.7 Ulll = = 14 a = = = — 6 = = = 8.9 17S 0 | — — = 32.0 — 0 — _ — 1Collected from only 1 m X 2 m portion of quadrat; all others are numbers for entire 2m X 3 m quadrat (Moderate wave action) or entire 1.5m X 2 m quadrat (Calm-water). 2Fissurellids were counted (on entire quadrat) but not measured in 1971, and the species were not separated; both species were present. 3All specimens collected in 1970 were removed permanently from the quadrat; for other species all but a few voucher specimens were returned to the quadrat within a few days after collection. turned to the quadrat within 24 hours; other individuals were preserved for later study. Some Q-11 snails were tagged to obtain growth rates. On 8 February 1970, 66 Thais melones (Duclos, 1832), 30 Acanthina brevidentata (Wood, 1828) and 10 Opea- tostoma pseudodon (Burrow, 1815) were given individu- ally numbered tags and returned to Q-11. When the com- plete collection was made (8 March 1970), 23 of these snails were recaptured, and on 21 March, 11 additional tagged snails were captured. No tagged snails were found in 1971. To evaluate the growth data, the observed increments of shell length were regressed on initial size. Of the 3 regressions, only that for Acanthina over the 8 February- 8 March interval was significant (F, ,=4.15; 0.10 >P > 0.05). Since growth was poorly correlated with size, the data are presented here as unweighted averages. RESULTS The collections made in 1971 are much more similar to those taken from the same quadrats in 1970 (Table 1) than to collections from other quadrats (SpPIGHT, 1976). For most species, both density and mean shell length were similar in 1970 and 1971. Furthermore, most of the in- dividuals kept for vouchers after the 1970 collection had been replaced by others of the same species by 1971. Species lists for the 2 years are not identical. Of the 18 species collected, 4 were found only in 1970, and 3 were found only in 1971 (Table 1). However, of these 7 species only Notoacmea biradiata was represented by as many as 8 individuals (1970; these were preserved). Densities and size distributions also changed between years (Figure 1). Along with limited growth data, these size distributions reveal the underlying processes that Vol. 21; No. 1 THE VELIGER Page 139 Thais biserialis Acanthina 1971 1971 Thais biserialis 1970 Thais melones 1971 Acanthina 1970 Thais melones 1970 Fissurella 1970 7m g 7) S be o Q g Acanthina Z 1971 Acanthina 1970 Anachis 1970 Siphonaria 1971 Siphonaria 1970 ° 10 20 Co) 10 20 Shell Length (mm) Figure 1 Sizes of snails collected from Q-8 and Q-11 during 1970 and 1971. saison Coa ee Sf 1), ine me alee edi De ms Acanthina brevidentata (A, B), Thais biserialis (C, D), Nerita es bas a nts en a . ate i ee ce ae funiculata (L, M), and Anachis costellata (N, O) were collected on ak nese Gore e 5 See a tala aE Ra TEE oe O refer to snails with thin lips, and the dark columns to snails with from Q-8, while Thais melones (E, F), Fissurella virescens (G), tick ips Page 140 maintain the composition of these gastropod assemblages. The data will be reviewed for each of the major species in turn. Acanthina brevidentata — The size distributions have definite peaks (Figure 1-A, B, H, I), and these probably correspond to year classes. The first peak is at about 10 mm, which is at the lower end of the yearling size range for typical temperate Thais (T.) emarginata (Deshayes, 1839), T. lamellosa (Gmelin, i791) and T. lapillus (Lin- naeus, 1758) (SPIGHT, 1975). The second peaks are at about 16mm and 1gmm, the latter typical for second- year T. emarginata and T. lapillus (SpicHT, 1972; FEARE, 1970a). However, 8- 10mm annual increments would require more rapid growth than that actually measured during the February-March period of 1970 (Table 2). Known spawning times are consistent with these age assignments. Acanthina deposited eggs on Q-8 during February, 1971, and elsewhere during March, 1970. If most snails spawn during February and March, then the smaller size peak (Figure 1) would represent snails al- most exactly 1 year old. However, temperate muricids that attain only 20- 25mm as adults spawn more than once (Thazs lapillus, FEARE, 1970b) and frequently re- peatedly throughout the year (7: emarginata, Houston, 1971; Eupleura caudata (Say, 1822), MacKeNnzmE, 1961). Acanthina may also have a long spawning season. The size distributions (Figure 1) indicate that many more recruits settled at some times and places than others. The size distribution for each quadrat is uni- modal in one collection and bimodal in the other. In 1970, the Q-8 population consisted entirely of yearlings, and the Q-11 population entirely of adults. Yearlings THE VELIGER Vol. 21; No. 1 were present on both quadrats in 1971, but fewer were found on Q-8 than had been found in 1970. Thus, during 1969 many snails recruited to Q-8, while only a few re- cruited to nearby Q-r1. The estimated annual growth performances and the observed dry-season growth rates are lower than typical temperate ones. Snails grow slowly when food is sparse (SpicHT, 1972) and food supplies appeared to be sparse at Playas del Coco. The major prey of Acanthina is Chthamalus (PatnE, 1966). The most common species at Playas del Coco, C. panamensis, is small and was sparse on both visits. Both barnacles and mussels were more abundant on Q-8 than on Q-11, and, appropriately, snails grew faster and reached larger sizes on Q-8. The Q-8 is a sandy area, and sand levels shifted during the observation period. At times the entire Q-8 area is probably submerged by the sand. The Acanthina breut- dentata on this quadrat were unusually numerous, and many more juveniles were found here than elsewhere. The size distributions may indicate recolonization after a recent burial. Thais melones — The size distributions and growth data indicate growth rates similar to those of Acanthina. Most snails found were 15 - 25mm (Figure 1-E, F) and these are assumed to be second year juveniles. Since the second-year snails of 1971 are not represented as first-year snails in 1970,-the actual annual growth performances are not clear. If snails settled after the 1970 visit, they must have reached 15 - 25mm in 10 months or less. How- ever, the tagged snails grew much more slowly. Alter- natively, the snails settled before the 1970 visit and I failed to observe them. Since the crevices on the quadrat Table 2 Net growth by three Costa Rican snails during the 1970 dry season. Size Range Net Size Increase (mm) Species N (mm) Maximum Mean SD r 8 February to 8 March Thats melones 13 12-36 1.0 0.49 0.29 0.094 Acanthina brevidentata 10 11-22 1.6 0.21 0.50 —0.584 8 February to 21 March Thais melones 94 15-29 2.6 0.80 0.84 —0.240 Acanthina brevidentata 7 15-16 0.5 0.45 = — Opeatostoma pseudodon 1 17 2.6 2.6 - - r, correlation between initial size and net size increase 4includes one of the snails recaptured 8 March ‘neither snail recaptured 8 March Vol. 21; No. 1 could provide hiding places for most snails 4 - 6mm long, the 15 - 25mm snails of 1971 could have settled as early as October or November, 1969. Assuming that fall is the normal settlement period, the year classes of 1968 and 1969 were about equally large, and the 1968 snails grew slightly faster than the 1969 ones. The Thais melones size range is similar to that of T. lamellosa (SpicHT, 1974), and therefore a similar mature size of 25 - 35mm can be expected for Playas del Coco snails. Thats biserialis — The size distributions do not have discrete peaks (Figure 1-C, D), and therefore growth rates cannot be derived. Most snails were 4 - 20mm, and these were probably first and second year juveniles. The continuous size distribution suggests continuous recruit- ment, in contrast to Acanthina. The size range should correspond to an adult size greater than 25mm (which is unusually large for a species that breeds throughout the year; SpicHT et al., 1974). No adults were present in 1970, and only a few were found in 1971. If the 1971 adults were among the juveniles collected in 1970, then each must have grown about 10mm during the year. The dense population of juveniles may indicate a recent colo- nization of Q-8. Anachis costellata — Shell morphology may indicate maturity, allowing snails to be aged. In 1970, the smaller snails had thin lips and rounded shoulders, while the larger ones had thick lips and square shoulders. If a thick- ened lip indicates maturity, then most snails mature at about 13mm (12mm is the largest size at which more than half of the 1970 snails had thin lips (Figure 1-O); mor- phologies were not noted in 1971). The size distribution was unimodal in 1970 (Figure 1-O) and bimodal in 1971 (Figure 1-N). If the 2 modes represent year classes, then the snails grew about 10mm during their second year. Many adults and few juveniles were found in 1970, while the same collection (from Q-8) yielded many juvenile and few adult muricids. Nerita funiculata — Size distributions for 1970 and 1971 (Figure 1-L, M) are more similar than those for any of the other Q-8 species. Both have the same mode at 7 - 9mm, suggesting that this species is an annual. On Barbados, 3 Nerita species all reach 10 - 13mm in their first year (HuGHEs, 1971b; all are mature at 14mm or more), and similar growth rates might be expected in Costa Rica. Fissurella virescens — These limpets (measured only in 1970) have a unimodal size distribution (Figure 1-G). No 0 - 20mm Fissurella were found. Either snails did not settle during 1969 or those that did grew rapidly. Fissur- ella barbadensis Gmelin, 1791 reaches about 26mm dur- THE VELIGER Page 141 ing its first year and generally not more than 30mm (HucHEs, 1971a), while F virescens frequently reaches 40mm (Figure 1-G). If F virescens and F barbadensis both grow at the same rate during the first year, then the 20 - 30mm limpets from Q-11 would be yearlings. DISCUSSION The answer to both questions posed in the introduction is “yes.” The assemblage of snails found on each quadrat in 1971 was very similar to that found on the same quadrat in 1970 — that is, much more similar than to the assemb- lage on any other quadrat at the same time. Furthermore, each species population was similar to the previous year’s because juveniles grew and recruits settled and estab- lished themselves. The individuals I removed in 1970 were replaced by recruits prior to the 1971 collections. If these 2 quadrats are typical, then the marked faunal differ- ences among quadrats (SPIGHT, 1977) are a persistent feature of this tropical site rather than an ephemeral feature which arises because snails are habitat generalists and are wandering from habitat to habitat. If distributions are persistent, do they reflect habitat selection, or could they arise through less predictable processes? Habitat selection ultimately reflects factors which affect the success of a species in different habitats. Both physical and biological factors affect success, and both lead to orderly and patchy distributions in temper- ate communities. Each shore level has a different regime of physical stresses. Species that tolerate the dehydration and temperature stresses of one level are often unable to tolerate the greater stresses found at higher levels and may be rapidly exterminated by predators at lower shore levels (CONNELL, 1972). As a result, most species have well-prescribed vertical (shore level) ranges, and these are the basis for universal schemes of shore zonation (STEPHENSON & STEPHENSON, 1972). Similar physical regimes in the more diverse tropical community could lead to even finer vertical division of the shore habitat. For temperate rocky shore species, physical and biotic factors also lead to patchy distributions. Recruits from many intertidal species are much more abundant in some years than others (CoE, 1956; LoosaNnorF, 1964; SPIGHT, 1975), food supplies are unpredictable (Spicut, i972), encounters with predators are both irregular and locally devastating (PAINE, 1974), and physical stresses are often near the tolerance limits of individuals (Davies, 1969; Foster, 1971). Within a shore level, these physical and biological stresses result in a continuing race between local extinction and recolonization (SricHT, 1974). Colonists Page 142 THE VELIGER Vol. 21; No. 1 establish themselves as patches become available on the shore, and for the most part, the patches bear little rela- tionship to the nature of the physical habitat (CONNELL, 1970; Dayton, 1971; Paine, 1974). With more species in the tropical community, there should be more kinds of biotic interactions, and these could, in turn, lead to more unpredictable distributions. The changes that did take place between years (Figure 1) do imply that these same physical and biotic processes are important at Playas del Coco. Recruits from most species were much more numerous during one year than the other. Acanthina brevidentata was abundant on both quadrats and recruits of this species were most abundant on the 2 quadrats at different times. Thus, recruitment appears to be as unpredictable as it is in temperate waters. Tropical snails grew slowly by both measures used (tag re- turns and analysis of size distributions). Snails usually grow slowly because food is scarce (SPIGHT, 1972), and even a predictably sparse food supply presents a major stress. The snail sizes on Q-8 suggest recoloniza- tion after a recent burial in sand, and thus unpredictabili- ty of the physical environment. Also, more kinds of pre- dators eat snails and together these predators are more numerous at Playas del Coco than at most temperate sites (personal observations). Activities of predators are a major cause of unpredictability in temperate waters. Appropriately, amid this array of physical and biotic stresses, the snail populations had not attained stable age distributions and showed no other evidence that the trop- ical rocky shore environment is more predictable for them than the temperate one. The distributions observed at Playas del Coco were per- sistent, but this does not necessarily indicate that they arose by habitat selection. Patchy distributions will arise and persist despite a uniform landscape if colonizers settle patchily and subsequent species interactions maintain the patches (Levin, 1974). For example, unique assemb- lages developed and persisted in each of the artificial oak logs placed by Facer (1968). The assemblages were best described as results of random colonization sequences to otherwise uniform habitats. Patches of some sedentary intertidal species persist for at least 6 years (PAINE, 1974). Although most species found on Q-8 and Q11 were found on both visits, the snails may have colonized these sites for- tuitously ; had other species arrived earlier, quite different assemblages could have developed and persisted. There- fore the present data provide no information about habi- tat selection and its potential role in the function of diverse tropical communities. Persistent distributional patterns are amenable to ex- perimental analysis, and experiments should clarify the role of habitat selection in tropical shore communities. Transplant experiments can be united with habitat modi- fications and selective removals to reveal factors influ- encing larval settlement and adult migrations. Such ex- periments will add a great deal to our now meager understanding of how tropical gastropods use shore hab- itats. SUMMARY Censuses of rocky shore gastropods were taken from 2 quadrats in northwest Costa Rica in 1970 and repeated in 1971. For most species, densities and average shell lengths did not change significantly. Recruitment varied in both time and space. Growth rates of thaisids were low relative to those of temperate species, in keeping with apparent scarcity of food. Distributional patterns may reflect habitat selection by the snails, but they may also be consequences of random colonizations and subsequent biotic interactions. ACKNOWLEDGMENTS I wish to thank C. Birkeland, E. M. Birkeland, B. Patten, and R. Spight for supporting various aspects of the field program, and E. Bragg and M. Gutierrez Sanchez for providing accommodations. Field work was greatly facili- tated by assistance from various members of the Organi- zation for Tropical Studies office in San Jose, Costa Rica. Identifications of all snails were verified by J. H. McLean. I gratefully acknowledge support from Organization for Tropical Studies Grant 69-34 and NSF Grant GB 6518 X to the University of Washington for field work, and from Woodward-Clyde Consultants for publication. Literature Cited Coz, Wes.tzy Rosweii 1956. Fluctuations in populations of littoral marine invertebrates. Journ. Mar. Res. 16: 212 - 232 Connext, Joszrn H. 1970. A predator-prey system in the marine intertidal region. I. Bala- nus glandula and several predatory species of Thats. Ecol. Monogr. 40 (1): 49-78; 9 figs. (Winter 1970) 1972. Community interaction on marine rocky intertidal shores, Ann. Rev. Ecol. Syst. 3: 169 - 192 Davis, Peter SPENCER 1969. Physiological ecology of Patella. III. Desiccation effects. Journ. Mar. Biol. Assoc. U. K. 49 (2): 291 - 304 (May 1969) Dayton, Paur K. 1971. Competition, disturbance, and community organization: The provision and subsequent utilization of space in a rocky intertidal com- munity. Ecol. Monogr. 41: 351-389; 17 text figs. Vol. 21; No. 1 Facer, Epwarp WILLIAM 1968. The community of invertebrates in decaying oak wood. Journ. Anim. Ecol. 37: 121 - 142 Feare, C. J. 1970a. Aspects of the ecology of an exposed shore population of dog- whelks Nucella lapillus (L.). Oecologia 5: 1 - 18 1970b. The reproductive cycle of the dog whelk (Nucella lapillus). Proc. Malacol. Soc. London 39: 125-137 Foster, B. A. 1971. On the determinants of the upper limit of intertidal distribution of barnacles (Crustacea: Cirripedia). Journ. Anim. Ecol. 40: 33 - 48 Houston, Roy S. 1971. Reproductive biology of Thais emarginata (Deshayes, 1839) and Thais canaliculata (Duclos, 1832). The Veliger 13 (4): 348 - 957; 1 plt.; 5 text figs. (1 April 1971) Hucues, Rocer N. 19714. Ecological energetics of the keyhole limpet Fissurella barbadensis Gmelin. Journ. Exper. Mar. Biol. Ecol. 6: 167-178 1971b. Ecological energetics of Nerita (Archaeogastropoda: Neritacea) populations on Barbados, West Indies. Mar. Biol. 11: 12 - 22 Levin, Simon A. 1974. Dispersion and population interactions. 207 - 228 Loosanorr, Victor Lyon 1964. Variations in time and intensity of setting of the starfish Asteri- as forbesi in Long Island Sound during a twenty-five year period. Biol. Bull. 126: 423 - 439 Mackenzig, Crype Lzonarp, Jr. 1961. Growth and reproduction of the oyster drill Eupleura caudata Amer. Natur. 108: THE VELIGER Page 143 in the York River, Virginia. Ecology 42 (2): 317-338; 12 figs.; 15 tables (April 1961) Mituer, ALAN CHARLES ‘ 1974. A comparison of gastropod species diversity and trophic struc- ture in the rocky intertidal zone of the temperate and tropical West Americas. Ph. D. thesis, Univ. Oregon, 143 pp.; 10 figs. Paing, Ropert TREAT 1966. Food web complexity and species diversity. 65 - 75 1974. Intertidal community structure: experimental studies on the relationship between a dominant competitor and its principal predator. Oecologia 15: 93 - 120 SricHT, Tom M. 1972. Patterns of change in adjacent populations of an intertidal snail, Thats lamellosa. Thesis (Ph. D.), Univ. Washington, 308 pp.; 48 Amer. Nat. 100: figs. 1974. Sizes of populations of a marine snail. Ecology 55: 712-729 1975. Ona snail’s chance of becoming a year old. Oikos 26: 9 - 14 1976. Censuses of rocky shore prosobranchs from Washington and Costa Rica. The Veliger 18 (3): 309-317; 1 text fig. (1 January 1976) 1977. Diversity of shallow water gastropod communities on temperate and tropical beaches. Amer. Natur. 111: 1077 - 1097 SpichT, Tom M., CHaries BrrKeLAND & ALANE Lyons 1974. Life histories of large and small murexes (Prosobranchia: Mu- Ticidae). Mar. Biol. 24: 229 - 242 STEPHENSON, T. A. & ANN STEPHENSON 1972. Life between tidemarks on rocky shores. W. H. Freeman & Co. San Francisco. xii+425 pp.; 20 color plts.; ca. 200 text figs. Page 144 NOTES & NEWS A New Species Record for Mytilopsis salle: (Récluz) in Central America (Mollusca : Pelecypoda ) BY DAN C. MARELLI AND ROBERT E. BERREND Department of Biology, San Francisco State University San Francisco, California 94132 Tue Genus Mytilopsis is the only New World representa- tive of the family Dreissenidae. Included in the genus are 6 New World species found from the southeast United States to Panama, and perhaps further south. All have been reported as inhabiting fresh to brackish water, all are byssiferous, and all have retained the trochophore and veliger larval stages in their invasion from the sea. All species have limited distributions, being generally con- fined to warm temperate or sub-tropical coastal bodies of fresh or brackish water. No overlap of species ranges has been reported, with the exception of the Panama Canal, in which both Mytilopsis sallei and Mytilopsis zeteki have been found. Mytilopsis sallei (Récluz, 1849) was first collected by Auguste Sallé from the Rio Dulce, Republic of Guate- mala. It was described as Dreissena salle: in 1849, and reassigned to the genus Mytilopsis by Conrad in 1857. Since 1849, M. sallet has been reported from the Gatun Locks, Panama Canal Zone (Jones & RUTZLER, 1975), and from the Visakhapatnam Harbor, India (Raju et al., 1975). In July of 1976, while studying the algal mats and stromatolites of Laguna Bacalar (18°51’/N; 88°31’ W), Quintana Roo, Mexico, we observed significant num- bers of M. salle: residing on the soft benthic sediments of the lake. Specimens were collected and preserved for later examination. Identification was made with the help of species descriptions and comparison with specimens THE VELIGER Vol. 21; No. 1 of M. leucophaetus, with which M. sallei is often con- fused. This location (Laguna Bacalar) represents a new rec- ord for Mytilopsts sallei. Its distribution in and around the lake has not been examined, but zoological work on this bivalve is forthcoming. Literature Cited Jones, M. L. a K. Rutzver 1975. Invertebrates of the upper chamber, Gatun Locks, Panama Canal, with emphasis on Trochospongilla leidit (Porifera). Mar. Biol. $$: 57 - 66 Raju, PB R., K. M. Rao, S. S. Gantz & N. KAtYANASUNDARAM 1975. Effect of extreme salinity conditions on the survival of Mytilopsis sallet Récluz (Pelecypoda). Hydrobiol. 46 (2-3): 199 - 206 Protoconch of Ovoviviparous Volutes of West Africa BY TWILA BRATCHER 8121 Mulholland Terrace, Hollywood, California 90046 (1 Text figure) THERE HAS BEEN a tendency among malacologists to interchange the words protoconch and nucleus. One glos- sary (BurcH, 1950) describes nucleus as “Apex or first part of the shell formed by the embryonic animal;” an- other (ARNOLD, 1966) as “the tip or earliest formed part of a shell.” In most species this is true. Therefore, it was interesting to note that in ovoviviparous volutes of the genus Cymbium observed in West Africa, the protoconch was the last part formed. From the bodies of females, young were removed in various stages of development from yolk to completely formed animals with shells. In several instances the shells were found completely formed except for the protoconch. A ball of yolk rested where the protoconch would be formed ultimately. A thin wall of shell was formed between the ball of yolk and the remainder of the shell. A number of these was taken from different females. At least 2, developed to this stage, were brought back by the expedition. In the newborn Cymbium, the protoconch is the most fragile part of the shell, being paper thin. If crushed, a ball of yolk is disclosed underneath. Vol. 21; No. 1 ACKNOWLEDGMENTS I wish to express my appreciation to Yvonne Albi for the accompanying sketches. THE VELIGER Page 145 Literature Cited ARNOLD, WINIFRED Haynes 1966. _A glossary of a thousand-and-one terms used in conchology. The Veliger 7 (Supplement): i-iv+5o0 pp.; 155 text figs. (dated: 15 March 1965, but actually published 15 March 1966) Burcu, Beatrice LARuE 1950. Illustrated glossary of Gastropoda, Scaphopoda, Amphineura. Concho]. Club South. Calif. Minutes 105 G Figure 1 A & B —- Newborn Cymbium pepo (Lightfoot, 1786], with fragile protoconch C through G — Unborn Cymbium marmoratum (Link, 1807) with shell developed except for protoconch ia\e toy Loe RICHMOND MEETING of the American Society of Zoologists, Society of Systematic Zoology, and the American Microscopical Society Tue American Society of Zoologists, Society of System- atic Zoology, and the American Microscopical Society will meet at the Hotel John Marshall in Richmond, size X 0.8 Virginia, December 27 - 30, 1978. Very low room rates are available ($18.- for single rooms and $24.- for doubles). The call for contributed papers has been issued and ab- stracts for the American Microscopical Society are due August 1, 1978. The other two societies have an abstract deadline of September 1. Symposia are being arranged on the following topics: Ultrasonic Communication in Rodents; Seasonal Breed- ing in Higher Vertebrates; Respiratory Pigments; Struc- ture, Function and Environmental Adaptations; Thermo- regulation in Ectotherms; Insect Thermoregulation; Cell Surfaces in Development and Cancer; Competition be- tween Distantly Related Taxa; Asexual Reproduction in Animals; Contemporary Methods in Systematic Para- sitology; Philosophical Issues in Systematics; Morphology Page 146 and the Analysis of Adaptation; Microscopical Structure and Distribution of Silicon in Biological Systems; and the Contribution of Electron Microscopy to Systematics. In addition, a Workshop on Major Problems in Crustacean Biology is being planned. The American Microscopical Society is celebrating its centennial year with an evening program of reminiscence, a banquet, and a Past-Presidential Address. Other spe- cial programs include “The Birth and Growth of the ASZ” sponsored by the Committee on the History of the American Society of Zoologists, “Should the ASZ Take Positions on Current Social Issues?”, a workshop-discus- sion by the Public Affairs Committee of the American Society of Zoologists and “Coccoliths to Dinosaurs: 100 years of Paleontologic Research in the U.S.” sponsored by the U. S. Geological Survey. A Wine and Cheese Party, a Reception and Luncheon following the ASZ Presiden- tial Address, and Divisional Cash Bar Socials will be arranged. Plans include Commercial Exhibits, a Job Placement Service and a Babysitting Service. For more information and abstract forms contact: Mary Wiley, Business Manager, American Society of Zoologists, Box 2739, California Lutheran College, Thou- sand Oaks, CA 91360 (telephone: 805-492-4055). Sale of C. M. S. Publications: Effective January 1, 1978, all back volumes still in print, both paper covered and cloth bound, will be available only from Mr. Arthur C. West, P. O. Box 730, Oakhurst, CA (lifornia) 93644, at the prices indicated in our Notes and News section, plus postage and, where applicable, California State Sales Tax. The same will apply to the Supplements that are still in print, except for supplements to vol. 7 (Glossary) and 15 (Ovulidae), which are sold by The Shell Cabinet, P O. Box 29, Falls Church, VI (rginia) 22046; and supplement to volume 18 (Chitons) which is available from Hopkins Marine Station, Pacific Grove, CA (lifornia) 93950. Volumes 1 through 8 and 10 through 12 are out of print. Volume 9: $22.- — Volume 13: $24.- - Volume 14: $28.- Volume 15: $28.- Volume 16: $32.- Volumes 17 to 20: $34.- each. Postage and handling extra. There is a limited number of volumes 9, 11, 13, 14 to 20 available bound in full library buckram, black with gold title. These volumes sell as follows: 9 - $27.-; 11 and 13 - THE VELIGER Vol. 21; No. 1 $29.- each; 14 and 15 - $33.- each; 16 - $38.-; 17, 18 and 19 - $41.75 each; 20 - $42.25. Supplements Supplement to Volume 3: $6.- [Part 1: Opisthobranch Mollusks of California by Prof. Emst Marcus; Part 2: The Anaspidea of California by Prof. R. Beeman, and The Thecosomata and Gymnosomata of the Cali- fornia Current by Prof. John A. McGowan] [The two parts are available separately at $3.- each] Supplement to Volume 6: out of print. Supplement to Volume 7: available again; see announce- ment elsewhere in this issue. Supplement to Volume 11: $6.-. [The Biology of Acmaea by Prof. D. P. Assorr et al., ed.} Supplement to Volume 14: $6.-. [The Northwest American Tellinidae by Dr. E. V. Coan] Supplement to Volume 16: $8.-. [The Panamic-Galapagan Epitoniidae by Mrs. Helen DuShane] Prices subject to change without notice. Orders for any of the publications listed above should be sent directly to Mr. Art West. If orders are sent to us, we will forward them. This will necessarily result in delays. A Glossary of A Thousand-and-One Terms Used in Conchology by Winirrep H. ARNOLD originally published as a supplement to volume 7 of the Veliger has been reprinted and is now available from The Shell Cabinet, Post Office Box 29, Falls Church, Virginia 22046, U.S. A. The cost is US$ 3.50 postpaid if remittance is sent with the order. Supplement to Volume 15: Our stock is exhausted, but copies are still available from The Shell Cabinet, P O. Box 29, Falls Church, Virginia 22046. [A systematic Revision of the Recent Cypraeid Family Ovulidae by Crawrorp Nem Care] Other supplements: [Growth Rates, Depth Preference and Ecological Succes- sion of Some Sessile Marine Invertebrates in Monterey Harbor by Dr. E. C. Haderlie] Supplement to Volume 17: Our stock of this supplement is exhausted. Copies may be obtained by applying to Dr. Vol. 21; No. 1 THE VELIGER Page 147 E. C. Haderlie, U. S. 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It is the stated aim of the Society to disseminate new infor-- mation in the field of malacology and conchology as widely as possible at the lowest cost possible. At a Regular Membership meeting of the Society in No- vember 1968 a policy was adopted which, it is hoped, will assist in building up the Endowment Fund of the Society. 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. Regarding UNESCO Coupons We are unable to accept UNESCO coupons in payment, except at a charge of $4.25 (to reimburse us for the ex- penses involved in redeeming them) and at $0.95 per $1.- face value of the coupons (the amount that we will receive in exchange for the coupons). 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We regret that we must insist on these conditions; however, the exorbitant in- creases in postal charges leave us no other choice. Some recent experiences induce us to emphasize that manuscripts must be in final form when they are sub- THE VELIGER Vol. 21; No. 1 mitted to us. Corrections in galley proofs, other than errors of editor or typographer, must and will be charged to the author. Such changes may be apparently very simple, yet may require extensive resetting of many lines or even entire paragraphs. Also we wish to stress that the require- ment that all matter be double spaced, in easily legible form (not using exhausted typewriter ribbons!) applies to all portions of the manuscript — including figure explana- tions and the “Literature Cited” section. It may seem inappropriate to mention here, but again recent experience indicates the advisability of doing so: when writing to us, make absolutely certain that the cor- rect amount of postage is affixed and that a correct return address is given. The postal service will not forward mail Pieces with insufficient postage and, if no return address is given, the piece will go to the “dead letter’ office, in other words, it is destroyed. BOOKS, PERIODICALS, PAMPHLETS Endodontoid Land Snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra) Part I Family Endodontidae by Aran SoteM. Field Museum of Natural History, Chicago, Illinois. pp. xii+1- 508; 208 text figures; 114 tables; 23 X32.5cm. $31.50, postpaid (29 Oct. 1976) As indicated in the extended title of this publication, a second part is in preparation. That part will deal with the families Punctidae and Charopidae. Part I, the present work, deals exclusively with the Endodontidae. The study is based on over 26000 specimens and both parts together will report on 45 genera including 285 species. The terms “genus” and “species” include “sub- genus” and “subspecies.” Of these taxa, 84% of the gen- era were not previously recorded, and 54% of the species are new to science. In the present volume 19 genus level and 102 species level taxa are recognized as new. While these statistics might be interpreted that the author is an extreme splitter and that the work harks back to 19” century taxonomy — nothing could be fur- Vol. 21; No. 1 ther from the truth. This becomes evident in the first three chapters, entitled: Previous Studies; Material Stud- ied; and Methods of Analysis. Decisions are not based on subjective impressions supported by cursory examina- tions with a hand lens. Nor are taxa established on the basis of a single chance specimen. For a critical evalution of the validity of the work it is important to carefully study the 80 page chapter en- titled Patterns of Morphological Variation. It is made clear in these pages how many different characteristics have to be taken into account and the rather staggering amount of careful observations combined with highly critical analyses that have gone into each decision. Sup- port is adduced with the aid of the most modern tech- nical means available — statistical analysis, scanning elec- tron microscopy, as well as, of course, the traditional methods. A brief chapter on Habitat Range and Extinction shows how little may be required to wipe out a species, but it also leaves the clear impression that in the majority of cases it is human influence that is the causative agent. Deforestation coupled with advancing agriculture elimi- nates the normal ecological conditions required by these highly specialized small animals. There is left little doubt in the mind of this reviewer that some of the taxa de- scribed as new in this monumental work have already been wiped out (many of the specimens used in this study had been collected in the first half of the current century). It also becomes clear why there seems to be a sudden increase in the number of taxa — most of these small snails occur in areas that have been difficult to reach and to explore; further, collecting them requires painstaking work with heavy investment of time in the field. The chapter on Phylogeny and Classification takes up 19 pages. Here computerization is used for the production of a possible “family tree.” The largest chapter is, of course, the Systematic Review, which takes the next 367 pages. Even a casual scanning reveals the thoroughness and critical care of the work. The superb drawings are convincing even the most skep- tical student. Well executed graphs help make clear the points the author is making. While the treatment of each species-level taxon is divided into the usual parts — diag- nosis, description, holotype, range, paratypes, material, and remarks — the thoroughness and clarity of each treat- ment are outstanding. The remainder of the work is divided into a brief chapter on Zoogeography (5 pages), a list of References (7 pages), a Systematic Index (about 6 pages), a Geo- graphic Index (a trifle more than one page), with a THE VELIGER Page 151 half-page Summary and a page of explanations of the anatomical terms used in the illustrations. It is our opinion that Dr. Solem’s work will be con- sidered a classic in its field and that it will be accepted as a standard of the best of twentieth century taxonomy. He is to be commended on his industry and endurance, which were needed to bring this work to its successful completion. R. Stohler Marine Shells of Southern California by James H. McLean. Natural History Museum of Los Angeles County, Science Series 24, Revised Edition: 1 to 104, 54 figures in text. $5.00. (20 March 1978) A compact and well-organized guide to some 318 species of mollusks of the southern California area, this work has brief descriptions and figures, with notes on habitat and range of all of the commoner intertidal forms in that region. Some that are less common and some from off shore also are included. The half-tone figures, from photo- graphs, are grouped in the text-figures either on the same page as, or adjacent tc the descriptions; all are clear enough for ready identification of species, even for the smaller forms. Although this is in the main a reprint of the 1960 first edition, nomenclature is updated. Changes of names that had become necessary are detailed in a new preface; also,_ notes on recent collecting regulations are given. The demand that soon exhausted the first edition showed how much a good local guide had been needed, and the author is to be commended for his skillful planning of a work useful to both the novice and the more experienced collector. A. Myra Keen The Turridae of the European Seas by Fritz Norpsrcx. La Conchigla, Rome. 131 pages; 144 pen-and-ink drawings on 26 plates. No price given. 1977 (probably late November) According to the postal marking, the book was mailed in Rome, Italy on November 30, 1977. It reached our desk on March 24, 1978, having been underway for almost a full 4 months. Unfortunately, the book, which measures Page 152 14 X 21cm, was obviously soaked in water somewhere in transit. The text and figures are printed on coated stock, as a consequence of which the pages are stuck together and it is impossible to separate the pages from each other without severe damage to legibility of text and precision of figures. If we, nevertheless, try to give what we consider a fair appraisal, it must be understood that this is based more on the earlier similar work by the same author, the 4 volumes we reviewed in our volumes 11, 12 and 16. As far as it is possible to ascertain, the format of the present work is identical with that of the ones to which we just alluded. The main difference seems to be that this work is limited to one family, which, from the foreword, is to complete the work begun in the earlier volumes. It is intended as a “chapter” of the total work and in- cludes 10 subfamilies, 59 genera and subgenera, 305 spe- cies and subspecies. It is probably safe to assume that, as before, there are many new taxa proposed in this book. On 2 pages which we were able to separate from each other more or less successfully, we find 10 subfamilies, 36 genera and 24 sub- genera. Of these, 2 are new names and 4 are new subgen- era. It is possible to “peek” between portions of pages in a few places. In every case it is possible to discern the symbol n. sp. after some names. But, unfortunately, the author also continues to establish “Forms” which have no standing in taxonomy. It may be assumed that this is done for the “benefit” of amateur shell collectors. In spite of this latter drawback, we think that the book will fill a useful purpose. R. Stohler Malacological Review Vol. 10 (1-2) : 224 pages; numerous figures in text. 1977. Published at the Museum of Zoology, University of Michigan, Ann Arbor, Michigan 48109, U.S. A., by the Society for Experimental and Descriptive Malacology. THE VELIGER Vol. 21; No. 1 Orders and subscription should be addressed to Dr. J. B. Burch, P O. Box 420, Whitmore Lake, Michigan 48189, U.S.A. The first article reviews the literature pertaining to the European pulmonate snail Helix pomatia. There are brief but cogent annotations to each citation. Six research articles follow: 2 deal with ecological facters inducing aestivation in Ferrisia wautieri; one deals with tolerance of Biomphalaria glabrata embryos of thermal stress; an- other describes 13 new species of land snails from the southeastern United States; the fifth article reports on intramarsupial suppression of fetal development in sphaer- iid clams, while the concluding paper deals with ana- tomical systematics of Cristaria plicata. There follow brief communications, 4 in number and the section News and announcements, Miscellanea, Obit- uaries and Book Reviews make up the remainder of the first section. The second section, as usual, is given over to a reproduction of the tables of content of 27 periodical publications in malacology on a worldwide basis. A very useful feature is the list of authors of all publications listed in the reproduced indices, giving the addresses of the authors. This should help prevent useless correspondence to editors requesting reprints, which should in most, if not in all, cases be sent to the respective authors. Some II pages list publications other than those found on the index pages. The concluding 3 pages are devoted to an index of the scientific names used in the research article. We were especially pleased to see on the inside back cover a requirement that we have long considered: vouch- er specimens of all species used in all papers must be deposited in a recognized repository. At the Veliger we have made this a recommendation, so far, as we have been unable to ascertain how many such repositories are available and what degree of checking the material for glaring errors in identification might be provided. But we certainly applaud this requirement and consider it long due. R. Stohler 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, cvtological, distributional, ecological, histological, morphological, phys- iological, taxonomic, etc., aspects of marine, freshwater or terrestrial mollusks from any region, will be considered. Even topics only indi- rectly concerned with mollusks may be acceptable. In the unlikely event that space considerations make limitations necessary, papers dealing with mollusks from the Pacific region will be given priority. However, in this case the term “Pacific region” is to be most liberally interpreted. It is the editorial policy to preserve the individualistic writing style of the author; therefore any editorial changes in a manuscript will be sub- mitted to the author for his approval, before going to press. Short articles containing descriptions of new species or lesser 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 geographical longitudes and latitudes added. Short original papers, not exceeding 500 words, will be published in the column “NOTES & NEWS"; in this column will also appear notices of meetings of the American Malacological Union, as well as news items which are deemed of interest to our subscribers in general. Articles on “METHODS & TECHNIQUES” will be considered for publication in another column, provided that the information is complete and tech- niques and methods are capable of duplication by anyone carefully fol- lowing the description given. Such articles should be mainly original and deal with collecting, preparing, maintaining, studying, photo- graphing, etc., of mollusks or other invertebrates. A third column, en- titled “INFORMATION 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 in- vited. The column “BOOKS, PERIODICALS, 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, 812” by 11”, double spaced and accompanied by a carbon 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 accom- modate the pamphlet (which measures 51/2” by 81/2”), with double first class postage, should be sent with the request to the Editor. EDITORIAL BOARD Dr. Donatp P. Assort, Professor of Biology Hopkins Marine Station of Stanford University Dr. WarrEN O. Appicott, Research Geologist, U. S. Geological Survey, Menlo Park, California, and Consulting Professor of Paleontology, Stanford University Dr. Hans Bertscu, Assistant Professor of Biology Chaminade University, Honolulu, Hawaii Dr. Jerry DononueE, Professor of Chemistry University of Pennsylvania, Philadelphia, and Research Associate in the Allan Hancock Foundation University of Southern California, Los Angeles Dr. J. Wyatt Duruam, Professor of Paleontology Emeritus University of California, Berkeley, California Dr. Caper Hann, Professor of Zoology and Director, Bodega Marine Laboratory University of California, Berkeley, California Dr. Joe. W. HepcpetTu, Adjunct Professor Pacific Marine Station, University of the Pacific Dillon Beach, Marin County, California Dr. A. Myra KEEN, Professor of Paleontology and Curator of Malacology, Emeritus Stanford University, Stanford, California Dr. Joun McGowan, Professor of Oceanography Scripps Institution of Oceanography, La Jolla University of California at San Diego Dr. FRANK A. Prrevxa, Professor of Zoology University of California, Berkeley, California Dr. Rosert Rosertson, Pilsbry Chair of Malacology Department of Malacology Academy of Natural Sciences of Philadelphia Dr. PETER U. Roppa, Chairman and Curator, Department of Geology California Academy of Sciences, San Francisco Dr. Ciype FE. Roper, Curator Department of Invertebrate Zoology (Mollusca) National Museum of Natural History Washington, D. C. Dr. JupirH Terry SmitTH, Visiting Scholar - Department of Geology, Stanford University Stanford, California Dr. Ratpu I. Smirn, Professor of Zoology University of California, Berkeley, California Dr. Cuartes R. STASEK, Bodega Bay Institute Bodega Bay, California Dr. Victor LoosanorF, Professor of Marine Biology Dr. T. E. Tompson, Reader in Zoology Pacific Marine Station of the University of the Pacific EDITOR-IN-CHIEF Dr. Rupotr STon.er, Research Zoologist, Emeritus University of California, Berkeley, California University of Bristol, England ASSOCIATE EDITOR Mrs. Jean M. Cate Rancho Santa Fe, California THE VELIGER A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California VOLUME 21 OcToBER 1, 1978 NuMBER 2 CoNnTENTS Papers on Neogene Mollusks of the North Pacific Margin: An Introduction NVARRENEOMADDICOMT Mas (es ake 2k sc cy te) a oa na le wo fee alee oe TS Neogene Molluscan Faunas in the Japanese Islands: An Ecologic and Zooge- ographic Synthesis (8 Text figures) Kryotaka CuHInzEI . . . . . . I BEE a oho Nea ein ah Merbr ce Vaniee tinea map Late Oligocene Through Pleistocene Molluscan Faunas in the Gulf of Alaska Region (2 Text ee RicHarp C. ALLISON. . Pe isriaee ce ; ae Se ctes ie Semammer al 7A] World-Wide Biostratigraphic Correlation Based on Turritellid eee (7 Text figures) SVAMIOSNOTAKAMEET ME eras Stag. se a me ee TOO Neogene Pectinidae of the Northern Pacific G Text ae IKGIGHIRO) MASUDA) 5 | 4 4.) 4 cane : . - 197 Neptunea (Gastropoda : Buccinacea) in the ae of the North Pacific and Adjacent Bering Sea (2 Plates; 9 Text figures) Cuirrorp M.Nrtson .... . SR eee ee ee ee Cr aN eR eee 2 OB Late Neogene Succession of Molluscan Fauna on the Pacific Coast of Southwestern Japan, with Reference to Planktonic Foraminiferal Sequence (6 Text figures ) RVUICHIMISUCGHT & MASAKOUIBARAKI 2 . 59 40.0 6s a ws ee ee IG Premises of Neogene Correlation in the Northern Part of the Circum-Pacific Yur B. GLapENKOV. .... . WBien Resides ovo ial Goulart umes, ton ALE Rees e226 History of the Pliocene Molluscan Fauna of Northern ue ae 1 Text Gcue Frank H.KirmMer. . eta oc . 227 Review of the Bivalve Genus Pi sladonive- frem the “Tertiary of California and the Description of Two New Species. (1 Plate) WiLuiaM J. ZINSMEISTER . . . . Seas esas Ss Ce ew ehalon, meog tence Pewee 22 [Continued on Inside Front Cover] 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 Second Class Postage Paid at Berkeley, California ContTENTs — Continued The Chromodoridinae Nudibranchs from the Pacific Coast of America. — Part IV. The Genus eau (1 Plate; Text figures 26 to 32) Hans BertscH . . EN ys RM a arise are eon ee ty Phe ee 4 PIGYS) The Effects of an eee Gastropod, Caledoniella montrouzieri, upon Molting and Reproduction of a Stomatopod Crustacean, Gonodactylus viridis. (2 Text figures) Marjorie Linpguist REAKA. . . : Shah ttebiais ; eBid ieee ONL Notes on the Cephalopods of Monterey ae California, with New Records for the Area. (4 Text are M. Eric ANDERSON . . . : Adie Ree No ou yO drenta MBS ORR Antipredator Behaviour in Octopus dofleini (oitcn). B. Hartwick, G. THorarinsson & L. Tuttocw ...... .. . . « 263 Mating Behavior of Octopus joubini Robson. JENNIFER A. MATHER... . . An re iag eu Upon Ana bb). ot AGG Growth in the Keyhole Limpet Fissurella crassa Lamarck (Mollusca : Archaeo- gastropoda) in Northern Chile. OF Text oe Marta BrETos ... . j : Satumoum rel eure Wer uc LoLs Abnormality of Shell Plates in Three Chitons from New pe (1 Plate) PAUL, D) IGANGER WI wet ie ence EE ae Meer ANI e me Maite Were de G. C274 Accumulation of '4C-Labelled Algal Exudate by Mytilus californtanus Conrad and Mytilus edulis Linnaeus, An Aspect of Interspecific Competition. (1 Plate; 3 Text figures) PIV PANTONE: Wn. M. Braytock « M.E.pe Burch... . . . . 276 Studies on the Mytilus edulis Community in Alamitos Bay, California: VII. The Influence of Water-Soluble Petroleum Hydrocarbons on Byssal Thread For- mation. Ropert Scorr Carrie, DonArD) Js REISH |) Ae ee ee eS Distributional Patterns of Juvenile Mytilus edulis and Mytilus californianus. PETER S, ‘PETRATTIS (2) 60 Ge 97) a) a Sic eh pa eA Ce a ne a ce 2 OO Flight Responses of Three Congeneric Species of Intertidal Gastropods (Prosobran- chia : Neritidae) to Sympatric Predatory Gastropods from Barbados. Danie L. Horrman, Witi1am C. Homan, Jay Swanson & PauL J. WELDON . 293 Winter Reproduction in the Gastropod Nassarius trivittatus. JAN’ A: PECHENIK() 05 2 Geo he ES ES es a 7 METHODS & TECHNIQUES ... . . 299 Laboratory Cultivation of Haminoea foltana (Say Baa) and Eivae Anite otica (Gould, 1870). (1 Plate) June F. Harrican & Danie. L. ALKON NOTES & NEWS . . . Mn MN ia eM en. A 1.8 So. ay SOR Additional Notes on S pupils aba (Risbec, 1928) (Mollusca : Opisthobran- chia). Gate G. SPHON Cypraea goodallii Sowerby, 1832 on Fanning Island. Hucu BRADNER Nematodes in the Alimentary Canal of Terrestrial Slugs. Dario _T. Cappuccl, Jr. Distributed free to Members of the California Malacozoological Society, Inc. Subscriptions (by Volume only) payable in advance to Calif. Malacozool. Soc., Inc. Volume 21: $30.- plus postage ($1.- in U.S. A.; $3.50 to all foreign Countries) Single copies this issue $30.00. Postage additional. Send subscription orders to California Malacozoological Society, Inc. 1584 Milvia Street, Berkeley, CA 94709, U.S. A. Address all other correspondence to Dr. R. StoH.eER, Editor, Department of Zoology University of California, Berkeley, CA 94720 Vol. 21; No. 2 THE VELIGER Page 153 Papers on Neogene Mollusks of the North Pacific Margin: An Introduction BY WARREN O. ADDICOTT U. S. Geological Survey, Menlo Park, California 94025 THE EIGHT PAPERS dealing with Neogene (Miocene and Pliocene) molluscan paleontology and biostratigraphy of the North Pacific margin included in this issue were pre- sented at the First International Congress on Pacific Neo- gene Stratigraphy held in Tokyo, Japan, May 17-21, 1976. These papers interrelate the Neogene biochronologies of different sectors of the North Pacific and trace the origin and development of the highly endemic Neogene mollus- can faunas of this region. Moreover, they provide an over- view of the status of knowledge of Miocene and Pliocene mollusks of the North Pacific and bring into focus the im- portance of molluscan research as a key to improved under- standing of the Neogene history of the Pacific basin. Two papers synthesize data on the faunal sequences of the northern margin of the Pacific (Alaska) and the middle latitudes of the western north Pacific (Japan). Kiyotaka Chinzei’s paper on the Japanese Neogene brings together the extensive biostratigraphic data from the Japanese Islands to detail the geographic shifts of warm and cool water faunas in response to climatic change. He also dis- tinguishes ocean, coastal, and embayment molluscan faunas in addition to benthic communities related to bot- tom topography and sediment texture. Richard Allison’s review and analysis of molluscan data from coastal Alaska clarifies the age and correlation of Neogene formations and sets the stage for much-needed detailed paleontologic study of the rich, mollusk-bearing sequences of the Gulf of Alaska and the Alaskan Peninsula. Papers by Tamio Kotaka, Koichiro Masuda, and Clif- ford Nelson deal with three of the best groups of mollusks for provincial and interregional correlation: the Turritel- lidae; Pectinidae, and Neptuneidae, respectively. The nep- tuneids seem to be best suited for interrelating the faunal sequences of the cool, high latitude parts of the North Pacific and show promise of striking comparisons with the North Atlantic. Turritellids, by virtue of their warmer water distributions are most useful in the biochronology of the middle and low latitudes, as indicated by Kotaka. The Pectinidae are excellent biochronologic indicators in all latitudes although Masuda shows that their Neogene distribution in the higher latitudes of the North Pacific is most promising in circum-North Pacific correlation. Temporal calibration of the molluscan sequence of southern Japan with the standard European Neogene sec- tions through tie-ins with planktonic foraminifers is treated by Ryuchi Tsuchi and Masako Ibaraki. This paper exemplifies the kind of research that is needed to correlate the oceanic microfossil sequences defined by recent deep- sea drilling, with the shallow water, nearshore sequences that are best characterized by mollusks and other larger invertebrates. Some aspects of high latitude correlation by mollusks and siliceous microfossils such as diatoms are con- sidered by Yuri Gladenkov based on studies of the Neo- gene of Kamchatka and Sakhalin. The origins of the diverse and well-known Pliocene mol- luscan fauna of northern Japan are found in genera that evolved in the western North Pacific during the late Paleo- gene and early Neogene or which migrated into this region from the Tethyan region to the southwest. According to Frank Kilmer the chronology of dispersal events of these Tethyan genera is similar to that observed in New Zealand but the rates of generic extinction are dissimilar. These papers were presented at sectional meetings on mollusks at the Neogene Congress which were attended by 30 to 40 specialists, mostly from the western North Pacific. As a consequence of the intense interest in Neogene molluscan phylogeny, biostratigraphy, and biogeography generated by these presentations, a cooperative effort to make these data and interpretations more widely available through publication was undertaken by Tsugio Shuto and myself. The only previously available information was in the form of brief resumes (see Sarro & Ujmé, 1977). These sessions also led to extended discussions of molluscan distributions around the North Pacific rim and to the formation of two working groups to stimulate and coordinate this kind of research: a working group on Mollusca (co-chairmen Sa- Page 154 THE VELIGER Vol. 21; No. 2 buro Kanno and W. O. Addicott) and a working group on North Pacific correlations of on-land Neogene sequences (co-chairmen R. C. Allison and Yuri Gladenkov). I am indebted to my co-editor, Tsugio Shuto of Kyushu University, Japan, for his helpful cooperation in planning the publication of these papers on Neogene mollusks. His report on the marine Neogene of southeast Asia, presented to the general session at the Tokyo meetings (SHUTO, 1977), complements the western North Pacific summaries of Chinzei, Tsuchi and Ibaraki, and Gladenkov that appear in this issue. Similarly, a summary of the Neogene mollus- can chronologies of the Pacific Coast States (ADDICOTT, 1977) complements Allison’s synthesis of Alaskan mollus- can biostratigraphy. Thanks are also due to the Regional Committee on Pacific Neogene Stratigraphy, and to its Chairman Nobuo Ikebe and Secretary-General Yokichi Takayanagi for their encouragement and support without which publication of these papers would not have been possible. Literature Cited ADDICOTT, WARREN OLIVER 1977- Neogene chronostratigraphy of nearshore marine basins of the eastern North Pacific. Internat. Congress Pacif. Neogene Strati- graphy, Proc., Tokyo, Japan, 1976: 151-175; 4 text figs. Saito, TsuNemasa & Hirosui Uyjueé (eds.) 1977- International Congress Pacific Neogene Stratigraphy, Proc., Tokyo, Japan, 1976: 433 pp. SuuTo, Tsucio 1977. Correlation of Neogene formations of southeast and south Asia by means of molluscan faunas: International Congress Pacific Neogene Stratigraphy, Proc., Tokyo, Japan 1976:133 - 144 Vol. 21; No. 2 THE VELIGER Page 155 Neogene Molluscan Faunas in the Japanese Islands: An Ecologic and Zoogeographic Synthesis KIYOTAKA CHINZEI Geological Institute, University of Tokyo, Hongo, Tokyo 113, Japan (8 Text figures) INTRODUCTION A VAST AMOUNT OF INFORMATION on the Japanese Neogene molluscan faunas has been accumulated since the late Pro- fessor Matajiro YOKOYAMA first described the Neogene mollusks from the Miura Peninsula, south of Tokyo, in 1920. In 1939, OTUKA outlined the Cenozoic marine and terrestrial faunas in Japan. He recognized two or three marine faunal provinces and showed different faunal se- quences for each province. His synthesis had a marked influence on later work. Since then, many investigators have tried to synthesize the historic and geographic distri- butions of the Neogene mollusks in Japan. Some of these syntheses are, however, biostratigraphically oriented with little attention to the environmental background of the faunas (e.g., IKEBE, 1954; AsANO & Hatal, 1967), and others are geographically, stratigraphically, or taxonom- ically limited (e.g., KoTAKA, 1958, 1959; MasuDaA, 1962; Uozum1, 1962; CHINZEI, 1963; Nova, 1966; IToicawa & SHIBATA, 1973). MASUDA (1973) discussed the geographic and stratigraphic distributions of the principal molluscan species in Japan, and divided the Japanese Neogene into 5 stratigraphic units. In this paper I intend to present a general picture of historic and geographic changes of the Japanese Neogene molluscan faunas in view of ecologic characters of the faunal constituents, and their local and regional distri- butions. The Neogene deposits of the Japanese Islands exhibit a major cycle of sedimentation. The cycle began in the early middle Miocene with rapid subsidence followed by grad- ual filling of the sedimentary basins. This general tendency was modified by local up- and down-movements in both basins and area of provenance. The geographic and strati- graphic distributions of the benthic molluscan faunas were primarily controlled by the history of sedimentation, and the characteristics of the water masses surrounding the Japanese Islands. Ecologically analogous associations, or fossil communities, occur at distinct stratigraphic levels where similar environmental conditions repeatedly ap- peared. The analogous associations consist of different species belonging to the same genus or to allied genera whose eco- logic requirements were essentially the same. They are found in the same sedimentary facies, such as offshore muddy facies, fine-grained sand facies of shallow embay- ments etc., at different horizons in the different areas. Thus the analogous relationships of these associations may be compared with ecologically parallel relationship observed among the Recent marine communities (THORSON, 1957). Based on this repetition, the Neogene molluscan faunas of Japan can be grouped into 4 faunas of different ages. These faunas represent 4 phases in the historical change of our Neogene Mollusca. They are the early Miocene fauna (occurring somewhere between 26 and 16 my), the early middle Miocene fauna (c. 16-14 my), the late Miocene fauna (12-5 my), and the Pliocene to early Pleistocene fauna (5-1 my). The late Pleistocene and Recent faunas may be regarded as a 5th fauna and represent the latest stage of our faunal history. On the other hand, the faunas of two different water systems, warm and cold, are recognized throughout the Neogene as well as today. The ecologically analogous rela- tionships are also observed between the warm and cold water fossil faunas. By tracing changes in faunal characters we can follow the sequential shift of water masses around the Japanese Islands. The chronology of the molluscan faunas and fossilif- erous strata is based on the correlation table compiled by IkEBE et al. (1972), and revised according to later informa- tion. The correlation was made principally on the basis of planktic foraminiferal biostratigraphy supplemented by the data from other microbiostratigraphy and radiometric dating. Since the molluscan fossils are frequently found in Page 156 the shallow water facies, their chronologic positions are not always determinable by planktic foraminifers. In such cases, the fossiliferous beds were placed chronologically based on local stratigraphic relationships and other indi- rect evidence. EARLY MIOCENE FAUNAS The early Miocene deposits are of limited distribution in the Japanese Islands, and their chronostratigraphy has not been established. The molluscan faunas also have not been very well documented. The faunas are associated with a minor transgression which was antecedent to and inde- pendent from the major middle to late Miocene transgres- sion. In northern Kyushu, a marine formation, the Ashiya Group, overlies thick coal-bearing formations of Paleo- gene age. The Group contains a shallow water molluscan fauna, the Ashiya fauna. The geologic age of the Group has been regarded by some as late Oligocene, by others as early Miocene. Recent studies have revealed that in the Nichi- nan area of southern Kyushu (Loc. 3, Figure 1), mollusks in common with the Ashiya Fauna are associated with the early Miocene planktic foraminifers, Globigerinita dissim- ilis, Globigerina hohri, and a few others (SHUTO, 1963). Medium-grained sandstone at the type locality of the Group (Loc. 1), is rich in mollusks, Glycymeris cisshuensis, Solen connectens, Dosinia chikuzenensis, Pitar matsumo- Warm Water Fauna ¢ Coastal water associations ao (Ashiya Fauna) Cold Water Fauna S0 Coastal water associations a (Asahi Fauna) -45°"4° ° Offshore water associations 6 ° 135 SS JAPAN SEA Ryukyu Islands : ee Nes y eee 125° 25° 130° 30° Figure 1 Distribution of the early Miocene molluscan faunas and presumed paleogeography of Japan during the early Miocene. Numerals in- dicate the fossil localities mentioned in the text; 1: Ashiya; 2: Kottoi; 3: Nichinan; 4: Moriya-yama; 5: Chichibu; 6: Asahi; 7: Chikubetsu THE VELIGER Vol. 21; No. 2 toi, Lucinoma nagaoi and other suspension feeding bi- valves (SHUTO & SHIRAISHI, 1971). The association may represent the sandy bottom community of a shallow sea. Black sandy mudstone of the Ashiya Group in the Kottoi area (Loc. 2) contains Venericardia subnipponica and An- gulus maximus with Cultellus izumoensis, Acila ashiya- ensis, and Saccella sp. (OkaMoTO, 1970). They are asso- ciated with lenses of Crassostrea sp. Batillaria takeharai is found in sandstone around the oyster banks. The Veneri- cardia-Angulus association may be a member of a subtidal muddy bottom community of an embayment. Crassostrea and Batillaria may represent an associated intertidal com- munity. A molluscan fauna, which has been regarded as early Miocene, is known from the Chichibu Basin (Loc. 5; Kanno, 1960) and the Moriya area (Loc. 4), both in central Honshu. They are different in species composition from the Ashiya Group except for some common species, such as Pitar matsumotoi, Dosinia chikuzenensis. The fauna is characterized by Anadara chichibuensis, Acila submirabilis, Venericardia tohunagat, Dosinia chikuzen- ensis, and other coastal water sandy bottom bivalves. The stratigraphic relationship between the Chichibu-Moriya and the Ashiya Faunas is uncertain. The Ashiya Fauna and the Chichibu-Moriya Fauna were most probably associated with warm water judging by the lack of apparently northern species and by the com- mon or dominant occurrence of such warm water genera as Anadara, Pitar, and Dosinia. Little is known about the offshore associations of early Miocene age. Portlandia tokunagat, P. watase: and some other nuculanid bivalves with Periploma besshoensts and Macoma optiva have been reported from several places along the Pacific coast including the Chichibu Basin in the mudstone referred to the lower Miocene. No reliable data, however, have been available on their bathymetric ranges and on the habitat relationship between the sandy shallow water faunas. Since Portlandia tokunagai and P. wataset are known from Sakhalin and Kamchatka (GLADENKOV, 1974), these species probably lived in the cold water areas. The northern species tend to live at progressively greater depths toward the south, a relationship that exists in the present-day marine environment. In the Recent environ- ment, a submerged tongue of cold water, the Oyashio Undercurrent, has been recognized under the surface Ku- roshio Current at about 300 to 1000 m off the east coast of central Honshu. The tongue brings benthic and planktic subarctic species southward as exemplified by OKUTANI (1972). It is natural to infer that P. tokunagai and its asso- ciated species extended their distribution southward into deep water by means of the cold water undercurrent. Vol. 21; No. 2 Occurrence of a shallow cold water molluscan fauna, named the Asahi Fauna, is known in central Hokkaido (Loc. 6). The fauna has been assigned to the early Miocene. No positive evidence, however, has been given on the geo- logic age of the fauna. It is contained in the Asahi Forma- tion, the basal part of the Neogene marine sequence in central Hokkaido (UozuM1, 1966; Kanno et al., 1968). The formation yields Mytilus tichanovitchi associated with Peronidia t-matsumotoi, P. elongata, Spisula onnechiuria, Thracia asahiensis, Tectonatica ezoana, and other less abundant species. A similar association was reported from the Sankebetsu Formation in the Chikubetsu area of north- western Hokkaido (Loc. 7), although M. tichanovitchi was not found there (KANNO & MATsuNO, 1960). The generic composition as well as the characters of the contained sedi- ments indicate that the association represents a coastal water fauna. The Asahi Fauna is quite different in species composi- tion from the Ashiya Fauna as well as from the overlying early middle Miocene subtropical fauna which will be mentioned later. The species of the Asahi Fauna are lim- ited in their distribution to Hokkaido or farther north. Mytilus tichanovitchi is reported from northern Sakhalin and Kamchatka (e.g., MAKIYAMA, 1934; GLADENKOV, 1974). The association is thus considered to represent a cold water fauna. The offshore type Portlandia tokunaga: association is also found in the muddy facies of the Asahi and the Sankebetsu Formations. EARLY MIDDLE MIOCENE FAUNAS The early middle Miocene was a turning-point in the Jap- anese Neogene history. It was the start of geosynclinal sinking in Northeast Japan and along the Japan Sea coast, and the start of transgression onto the denuded hilly lands in the central part and on the Pacific coast of Southwest Japan. Shallow marine sediments cover the subaerial vol- canic and clastic deposits, or the pre-Tertiary rocks. The transgressive marine deposits contain abundant molluscan and other benthic faunas of shallow water type. The faunas are dominated by tropical and subtropical ele- ments and they spread over most of the Islands (Figure 2). No true reef facies have been found in the main Japanese islands. The cold water fauna occurs only in northern Hokkaido, and the offshore associations in northern and central Honshu and Hokkaido. Tropical molluscan associations were described by Tsuna (1960) from the Yatsuo area (Loc. 13), on the Japan Sea coast of central Honshu. In the Yatsuo area poorly sorted, dark grey muddy sandstone interdigitates with THE VELIGER Page 157 Warm Water Fauna ¢ Coastal water associations adonosawa Fauna) Cold Water Fauna ; + Coastal water associations (Chikubetsu Fauna) 3 ° Offshore water associations — Warm Water = Cold Water © Presumed Land Area Figure 2 Distribution of the early middle Miocene molluscan faunas and presumed paleogeography of Japan during the early middle Mio- cene. Numerals indicate the fossil localities mentioned in the text; 8: Tanega-shima; 9: Shobara; 10: Ogurui; 11: Morozaki; 12: Mizunami; 13: Yatsuo; 14: Nanao;_ 15: northern tip of the Noto Peninsula; 16: Moniwa near Sendai; 17: Kadono- sawa; 18: Okushini Island; 21: Gampo; 22: Myonchon 19: Takinoue; 20: Uryu; the conglomerate of deltaic facies. The sandstone contains Gelotna stacki, G. yamanet, Anadara daitokudoensts, Tele- scopium schenki, Vicarya yokoyamai, Cerithidea yatsuo- ensts and other gastropods and a few bivalves. The asso- ciation is comparable with the present-day mangrove swamp community (OYAMA, 1950), and indicative of the tropical nature of the early middle Miocene faunas. The same Geloina association was reported from the Shobara area in western Honshu (Loc. 9). Other tropical mollusks were reported from the Ogurui area (Loc. 10; KoBayAsHi & Horikosui, 1958). They are Globularia nakamurai, Conus cf. jenkinsi, Rochia japo- nica, Turbo cf. ticaonica, and the nautiloid Aturia mino- ensis. The gastropods are all equatorial genera that live on clean sandy bottoms facing an open sea. Globularia naka- murai was also found in the Shobara area (Loc. 9). The characteristic elements of the mangrove swamp community, Geloina and Telescopium, are restricted to central and western Honshu, while the other species, such as Anadara and Vicarya, are known over the Japanese Islands as far north as southern Hokkaido. In Okushiri Island, Hokkaido (Loc. 18), Anadara daitokudoensts, Sole- tellina minoensis, Vicaryella notoensis, Vicarya yokoya- Page 158 THE VELIGER Vol. 21; No. 2 mai, and some other species are found in dark grey, fine- grained sandstone, associated with oyster banks (UozuMI & Fuji, 1966). The composition of the association is typical of the Anadara-Vicarya association found in other areas of Japan, and is an example of a subtropical tidal flat com- munity. The habitats of subtropical coastal water communities and their areal distribution were reconstructed in the Ka- donosawa Basin of northern Honshu (Loc. 17). In this basin, the basal bed of the marine Kadonosawa Formation was deposited in a small U-shaped embayment (Figure 3). Five autochthonous molluscan associations have been dis- tinguished in this basal bed (CHINZEI & IWASAKI, 1967). The black muddy sandstone distributed in the bayhead and the marginal parts contains Batillaria yamanari and Macoma cf. incongrua associated with Soletellina mino- ensis, Saxolucina k-hatai, Cyclina japonica, Ringicula ninohensis, and Vicarya callosa japonica. The association is dominated by deposit feeding species. Although Ana- Mo tuuscan AssociaTIONS O Batillaria @ Crassostrea Anadara - Dosinia ® Felaniella O Macoma - Lucinoma LITHOFACIES Sandy mud Black muddy sand Grey muddy sand [=] Clean sand [2-".°] Gravelly sand Figure 3 Distribution of the coastal water associations in the basal part of the early middle Miocene Kadonosawa Formation in the Kadono- sawa Basin (Locality 17), north of Honshu. Thick line indicates the presumed coastline. Redrawn from Cuinze1 & Iwasaki (1967) dara daitokudoensis has not been found, the association is equivalent to the Anadara-Vicarya association, and repre- sents the tidal flat community. In front of the tidal flat facies, there are banks of a thick-shelled oyster, Crassostrea gravitesta. Oysters are found as clusters in grey muddy sandstone. Compsomyax iizukai, Panopea kanomatazawa- ensis, and Euspira meisensis are found among the oysters. The main part of the restored bay is occupied by non- stratified, grey muddy fine-grained sandstone. The sand- stone contains abundant shallow-burrowing suspension feeding bivalves including Dosinia nomurai, Clinocard- ium shinjiense, Anadara ninohensis, Compsomyax tizukai, and Tapes stratoriensis. Other species, such as, Panopea kanomatazawaensis, Glycymeris cisshuensis, and Euspira meisensis, are also commonly found. Solitary shells of Crassostrea gravitesta occur sporadically in the fossiliferous sandstone. This association is considered a sandy bottom community that lived in the central part of the shallow bay. Clusters of Felaniella usta occur in well sorted medium-grained sandstone near the bay-mouth. Felaniella is associated with Conus tokunagai, Tapes siratoriensis, and Euspira meisensis. In sandy mudstone outside of the bay, there is an asso- ciation composed of Macoma optiva with Lucinoma annu- lata, Mizuhopecten kimurai, and Anadara sp. This associ- ation represents a shallow muddy community in the Kado- nosawa Basin. The fauna has been called the Kadonosawa Fauna (OTuKA, 1934), and is considered representative of the Japanese early middle Miocene subtropical faunas. The Kadonosawa type molluscan fauna is known from more than go localities in Japan as shown in Figure 2. The fauna in one locality is usually composed of two or three associa- tions corresponding to associations in the Kadonosawa Basin. Mixed occurrences of the species which constitute the different associations in the Kadonosawa Basin are also commonly found. The mixing might have happened in some cases during sedimentation. The northernmost distribution of elements of the sub- tropical Kadonosawa Fauna is in the Uryu Coal-Field, cen- tral Hokkaido (Loc. 20; OHARA & KANNO, 1973). In this area, sandstone of the lower middle Miocene Shinuryu Formation contains Anadara ogawat, Dosina nomurai, Tapes siratoriensis, and Euspira meisensis; this association is analogous to the Anadara-Dosinia association in the Ka- donosawa area. A similar molluscan fauna is known from the Takinoue Formation (Loc. 19) which overlies the Asahi Formation containing the cold water Asahi Fauna. In the Takinoue Formation elements of the Batillaria association, Batillaria yamanarii and Macoma incongrua, etc., have been reported in addition to Dosinia nomurai, Tapes sivatoriensis and other sandy bottom mollusks Vol. 21; No. 2 THE VELIGER Page 159 (KaNNO & OcaAwa, 1961). Mollusks from Tanega-shima (Loc. 8), south of Kyushu, are the southernmost record of the Kadonosawa Fauna (Hayasaka, 1969). Included are Anadara daitokudoensis associated with Vicarya callosa japonica, Cerithidea shirakii, and some other potamid gas- tropods with banks of Crassostrea gravitesta. The Kadonosawa Fauna is known along the Japan Sea coast of the Korean Peninsula. In the Gampo area, south- eastern Korea (Loc. 21), the middle Miocene Eoil Forma- tion contains the Anadara-Vicarya association identical to the Japanese tidal flat community, as well as beds of Crass- ostrea gravitesta (KM et al., 1974). The same association was reported from the basal part of the Miocene Meisen Series in the Myonchon (Meisen) area of northern Korea (Loc. 22). Many of the characteristic species of the Kado- nosawa Fauna were first described from here by MAKI- YAMA (1926, 1936). The upper part of the Series is rich in late Miocene cold water mollusks as discussed later. A belt of marine sedimentation was formed through western Honshu in an east-west direction during the mid- dle Miocene. This belt of sedimentation is called the Setouchi Province, antecedent of the present-day Setouchi Inland Sea. The marine deposits of the Setouchi Province contain abundant molluscan fossils, especially in the lower part, the transgressive lower middle Miocene. ITOIGAWA & SHIBATA (1973) distinguished 16 associations in the Mizu- nami and surrounding area, eastern Setouchi Province (Loc. 12), ranging in habitat from intertidal to uppermost bathyal and from gravel-rock to muddy facies. Thirteen of these are shallow water associations. They are basically comparable with those in the Kadonosawa area, but there are some differences in species composition. Among the associations they described, that dominated by Saccella miensis, Venericardia siogamensis and Cultellus izumoen- sis, associated with Mfacoma optiva and Lucinoma acuti- lineatum, is typical of the shallow water muddy bottom community. The subtidal muddy bottom association is poorly represented in the Kadonosawa and other areas. In detail, the muddy bottom association is divided into two parts, the Saccella-Cultellus and the Macoma-Lucinoma associations (IToIGAWA, 1974). The latter probably lived in deeper water than the Saccella-Cultellus association. Gravel bottom communities are characterized by the abundant occurrence of pectinid species. In the Nanao area (Loc. 14) of the Noto Peninsula, central Honshu, Nanaochlamys notoensis, Kotorapecten kagamianus, Pla- copecten akihoensis occur in loose, pumiceous sandstone (Masupa, 1962). The association is typical of the subtrop- ical shallow sea pectinid-rich communities; associations of similar composition have been recorded from many places in northeastern Honshu and southern Hokkaido (Masupa, 1962). Conglomeratic sandstone of the Moniwa Formation near Sendai (Loc. 16) isan example. It yields Chlamys ara- kawat, C. cosibensis, Aequipecten yanagawaensis, in addi- tion to the species known from Nanao. Rocky bottom communities are uncommon among the early middle Mio- cene faunas. Masupa (1966) described the rocky bottom mollusks from the tip cf the Noto Peninsula (Loc. 15), where Haliotis notoensis, Turbo ozawai, Nerita ishidae, and Cypraea ohiroi are found in association with fragments of corals, larger foraminifers in the conglomeratic sand- stone of the Higashi-Innai Formation. The cold shallow water molluscan fauna of early middle Miocene is known only in northern Hokkaido. In the Chi- kubetsu area (Loc. 7), the middle Miocene Chikubetsu Sandstone contains Spisula onnechiuria, Peronidia t-mat- sumotot, Mercenaria chitaniana, Mya cuneiformis, Tecto- natica ezoana, Neptunea oomurai and some other mollusks (KANNO & Matsuno, 1960). The mollusks are shallow water inhabitants judging by the generic composition and lithologic characters of the enclosing sediments. However, there are no species in common with the Kadonosawa type sandy associations, and the Chikubetsu Fauna is thus con- sidered to be the cold water counterpart of the subtropical sandy bottom communities. The same cold water associa- tion was reported from the lower part of the Shinuryu For- mation in the Uryu area (Loc. 20). It is worthy of note that in the Shinuryu Formation, the Kadonosawa type Ana- dara-Dosinia association is found from the horizon slightly lower than that of the Chikubetsu Fauna (OHARA & K ANNO, 1973). his indicates the contemporaneity of the Kadono- sawa and the Chikubetsu Faunas. The occurrence of the offshore molluscan fauna is spo- radic when compared with the shallow coastal water asso- ciations. The lower middle Miocene nearshore sediments in the Setouchi Province are succeeded by offshore type mudstone containing planktic foraminifera and other oceanic planktons of southern aspect. The mudstone is poor in benthic mollusks. Locally nuculanid bivalves, Portlandia tohunagai, P. watasei, Malletia inermis, Yoldia sagittaria, are found in association with Periploma bessho- ensis, Lucinoma acutilineatum, Akebiconcha chitanii and some other bivalves (e.g., Loc. 11, SHIKAMA & KASE, 1976; Loc. 12, Iroicawa, 1960). The muddy fauna characterized by P. tokunagai and M. inermis is found in several other areas of north-central Honshu and Hokkaido. The species composition is strikingly uniform throughout these areas. The same association is also found in the early Miocene deposits and the Asahi and the Sankebetsu Formations in central Hokkaido as noted before. The bathymetric rela- tionship between the Portlandia association and the sub- tropical Kadonosawa Fauna is assumed to be the same as Page 160 that seen in the early Miocene faunas. The cold water type Portlandia association extended its distribution southward into deep water, transported possibly by the previously mentioned cold water undercurrent. Vertical stratification of warm and cold water masses in the Mizunami area (Loc. 12) is proved by the fact that the warm water nautiloid, Aturia minoensis, is preserved in association with cold water benthic mollusks. In early middle Miocene time, the convergence of warm and cold currents was presumably located in central Hok- kaido as indicated by the distribution of two shallow water molluscan faunas. The location is about 8° N of the pres- ent-day convergence of the warm Kuroshio and cold Oya- shio Currents, which is at about 36°N latitude with seasonal fluctuations, along the Pacific coast of Japan. On the other hand, the middle Miocene undercurrent of cold water probably reached down to central Honshu, about 35° N, as suggested by the distribution of the P. tokunagaz association, the position approximately the same as today. OKUTANI (1972) noted the reduction of size among the sub- arctic mollusks which are living in the Oyashio Undercur- rent in Sagami Bay, central Honshu. Nosuch phenomenon has been reported for the Miocene deep water species. MIDDLE MIOCENE FAUNA Middle Miocene deposits in the Japanese Islands are pre- dominated by offshore mudstone. They are represented by hard diatomaceous shale in the Japan Sea coast areas where the shale has been called the Onnagawa Formation and other local names. The diatomite is thought to have been accumulated in silled and stagnant basins (INGLE & GARRI- SON, 1976). Shallow water sediments positively able to be correlated with the middle Miocene mudstone and shale facies are not known. Most of the Japanese Islands are likely to have been submerged in deep quiet waters. The shale as well as clastic mudstone is extremely poor in benthic megafossils. Scat- tered mollusks including Portlandia tokunagat, Concho- chele disjuncta, Lucinoma acutilineatum, and some other bivalves have been reported from the mudstone. The mol- luscan fauna of this age is very poorly understood. LATE MIOCENE FAUNAS The shallow water sediments reappeared in the late Mio- cene along the marginal parts of the basins and surround- ing the newly emerged lands in Northeast Japan and the Japan Sea coast areas. The sediments are rich in molluscan fossils. In the depocenter of the basin, the middle Miocene THE VELIGER Vol. 21; No. 2 shale and mudstone is succeeded by grey siltstone or fine- grained sandstone containing offshore type mollusks. The age of reappearance differs from place to place; the earliest may have been in the middle Miocene, around 12 my ago. Apparently tropical and subtropical mollusks, which predominated during the early middle Miocene disap- peared from Northeast Japan and the Japan Sea coast prior to the late Miocene. The subtropical fauna was restricted to the Pacific coast of Southwest Japan (Figure 4). Warm Water Fauna e Coastal water associations + Offshore water associations (Kakegawa Fauna) Cold pare Fauna ~~ FN _»| Warm Water \ Z Cold Water ioe = umed Land Area Figure 4 Distribution of the late Miocene molluscan faunas and presumed paleogeography of Japan during the late Miocene. Numerals indi- cate the fossil localities mentioned in the text: 23: Miyazaki; 24: Fujina in Sanin District; 25: Zushi in the Miura Peninsula; 26: Shiobara 27: Tanagura; 28: Yama in the Aizu District; 29: Nanakita, north of Sendai; 30: Ichinoseki; 31: Kurikoma; 32: Kurosawa; 33: Atsunai; 934: Togeshita; 935: Wakkanai The late Miocene subtropical fauna is typically seen in the Miyazaki area (Loc. 23), southern Kyushu. Muddy sandstone of the lower Miyazaki Group contains Paphia exilis, Amusstopecten ttomiensis, Crassatellites tenuitltra- tus, associated with Joannisiella cummingi, Dosinia spp., Cardium spp., Clementiaand other bivalves and gastropod species (SHUTO, 1961). The fauna is comparable in generic composition to the Recent inner sublittoral sandy commu- nities of an open coast. The association of outer sublittoral character is found in sandy siltstone of the lower to middle part of the Miyazaki Group. It consists of Acila submira- bilis, Limopsis obliqua, Glycymeris rotunda, Nemocar- dium samarangae, Ancilla otukai, Polinices reiniana, and rn Vol. 21; No. 2 some other minority species. No intertidal community is known in the fauna. The fauna has a close similarity to the Plio-Pleistocene Kakegawa Fauna, which will be discussed later, both in species composition and in distribution. Late Miocene and Plio-Pleistocene faunas both lived in coastal and offshore waters probably affected as today by the warm Kuroshio Current. The differences between them may be attributed simply to their differing geologic ages. They are both called the Kakegawa Fauna in this paper. In southern Kanto, there is a peculiar assemblage com- posed of shallow water rocky or gravelly bottom species mixed with offshore deep water forms. The basal conglom- erate of the Kazusa Group in the Miura Peninsula (Loc. 25) contains Chlamys miurensis, Amussiopecten titomien- sis, Glycymeris cisshuensis, Turbo sp., Haliotis sp., asso- ciated with Phanerolepida transenna, Mikadotrochus yo- shiwarat, Halicardia sp., and other deep water species (SHIKAMA, 1973). Analogous mixed assemblages are found in several localities of the same horizon in Kanto. Two late Miocene cold water faunas, the nearshore Shio- bara Fauna and the offshore Yama Fauna, have been rec- ognized in Northeast Japan and along the Japan Sea coast (CHINZEI, 1963). The species characteristic of the Shiobara Fauna were first reported from the Shiobara area, central Honshu (Loc. 26) by YokoyAMA (1926). Composition of the fauna and its relation to habitats in the Tanakura and Shiobara areas were described by Iwasaki (1970). An embayment of late Miocene age has been restored in the Tanakura area (Loc. 27). The horizontal distribution pattern of mollusks in the restored bay is similar to that in the early middle Miocene Kadonosawa Basin. In front of the fresh water sand and lignite areas of the bayhead, there is a belt of banks and colonies of Crassostrea gigas with some other species. This represents the tidal flat community. Inside the belt of oyster banks, an area of the Anadara-Dosinia association occurs. The association is characterized by high diversity of species and large numbers of individuals. It is domi- nated by Anadara ninohensis, in association with Dosinia kaneharai, Felaniella usta, Laevicardium shiobarense, Glycymeris cisshuensis, Protothaca tateiwai, other shallow- burrowing bivalves, and with the gastropods Neverita kiri- taniana and Phos iwakianus. The association is equivalent to the Anadara-Dosinia association in the Kadonosawa Basin. The main part of the bay is occupied by massive fine-grained sandstone, in which Lucinoma annulata, Ma- coma optiva, Turritella tanaguraensis are found. This is comparable with the early middle Miocene Lucinoma- Macoma association of subtidal muddy bottom. There are small lenses of pumiceous coarse-grained sandstone in the massive sandstone area. The lenses contain a pectinid asso- THE VELIGER Page 161 ciation consisting of Mizuhopecten paraplebejus, Miyagi- pecten matsumoriensis, Chlamys kaneharai, with Glycym- eris yessoensis and a few other species. The occurrence of Dosinia kaneharai, Laevicardium shiobarense, and Chlamys kaneharai is a characteristic fea- ture of the Shiobara Fauna. The fauna has been reported from the northern margin of the Kanto Basin, and extends farther along the row of islands which was emergent during middle and late Miocene at the position now occupied by the Ou Range. In the Kurikoma area (Loc. 31), central Ou Range, the fauna is characterized by Spisula kurikoma, a species common in northern Honshu and Hokkaido, in addition to Dosinia kaneharai and Laevicardium shioba- rense. The same fauna has been called the Togeshita Fauna in Hokkaido, and is known from several areas, e.g., Toge- shita (Loc. 34), Atsunai (Loc. 33), in central and eastern Hokkaido (Uozum1, 1962). In the Sanin district (Loc. 24), western Honshu, the Upper Miocene Fujina Formation, consisting of fine-grained sandstone, contains Anadara oga- wat, Dosinia kaneharai, Mercenaria yokoyamai, Cultellus izumoensis, and others accompanied by Nautilus izumo- ensis. The fauna, characterized by occurrence of Anadara ogawai, Laevicardium shiobarense, Dosinia kaneharai and other species of the Shiobara Fauna, is known from the upper part of the Miocene Meisen Series in northern Korea (Loc. 22; MAKIYAMA, 1936). The shallow water type Shiobara Fauna is composed of Anadara, Dosinia, and other genera derived from the Indo- Pacific region intermingled with such northern species as Glycymeris yessoensis and Spisula kurikoma, etc. Since there are no apparent warm water species in the fauna, the Shiobara most probably lived in cold water, presumably coastal water in the temperate region. The Indo-Pacific elements may be considered as the descendants of invaders from the south in the early middle Miocene, who remained in the coastal area after the retreat of the warm current and succeeded in adapting themselves to cold water. The offshore type Yama Fauna was first described by Nomura (1935) from the Aizu area (Loc. 28). OTuKA (1941) noticed its offshore nature based on an association from the Kurosawa area (Loc. 32). In Hokkaido, the fauna of the same composition is called the Wakkanai Fauna (UozuMi, 1962). The Yama Fauna is characterized by buc- cinid and neptuneid gastropods, such as Ancistrolepis mogamiensis, Buccinum ishidai, Neptunea nomurai, and by the cardiid bivalves Serripes groenlandicus and S. yoko- yamai, associated with Conchocele bisecta and other bi- valves. Analogous associations of species are living in sub- arctic water in outer sublittoral to upper bathyal zones. Characteristic species of the Yama Fauna are found soli- tarily or a few species together in grey siltstone accumu- lated in the basins west of the row of newly emerged Page 162 islands. In Hokkaido, it is known from the Wakkanai Shale (Loc. 35) and its equivalents, in which the species of the Yama Fauna are associated with Portlandia watasei, P. thraciaeformis and others. The association intermediate in character between the offshore type Yama Fauna and the nearshore Shiobara Fauna is frequently found in fine-grained sandstone dis- tributed between the shallow water sand facies and the deep water mud facies. The fossiliferous K urosawa Forma- tion in the Kurosawa area (Loc. 32) becomes sandy east- ward, closer to an inferred island, where it contains Ma- coma optiva, Lucinoma acutilineatum, Panomya simoto- mensis, and Cultellus izumoensis, with Serripes spp. and a few gastropods (HayasaKA, 1957). Similar fine-grained sand associations are dominant in the basins east of the row of islands, e.g., Ichinoseki (Loc. 30), Nanakita (Loc. 29), and Kadonosawa areas (Loc. 17). Miyagipecten matsumo- riensis is another characteristic species of this fine-grained sandstone facies. Conglomeratic sandstone of the same ho- ‘rizon yields a pectinid association characterized by Mizu- hopecten kimurai, Kotorapecten yamasakii, and K. tryb- lium (e.g. Loc. 17, Masupa, 1962). PLIOCENE anD EARLY PLEISTOCENE FAUNAS Structural growth of the Japanese Islands became pro- nounced during thé Pliocene and early Pleistocene, dur- ing which time the areas of marine sedimentation were re- duced to the coastal belts of the Pacific and Japan Sea. A minor transgression is recognized, however, in Northeast Japan in the late Pliocene. It formed deep embayments in the Pacific side of northern Honshu and central and north Hokkaido. Faunal characters and their distribution during the Pliocene and early Pleistocene were not markedly dif- ferent from the preceding late Miocene, although some constituent species were replaced by new forms (Figure 5). A warm water fauna of Pliocene and early Pleistocene age, the Kakegawa Fauna, is distributed along the Pacific coast of Southwest Japan. This fauna comprises associa- tions of diverse habitats, from inner sublittoral to bathyal zones. The fauna is comparable to the living fauna in cen- tral and western Japan in the waters associated with the Kuroshio Current. A typical set of the associations is ob- served in the Kakegawa Group in the Pacific coast of cen- tral Honshu (Loc. 37). The Kakegawa area has been stud- ied repeatedly, and faunal characters are best understood here among the distribution areas of the Kakegawa Fauna (e.g., MAKIYAMA, 1931; IT'sucHI, 1960). } THE VELIGER -38: Kurotaki in the Boso Peninsula; Vol. 21; No. 2 Warm Water Fauna + Coastal water associations © Offshore water associations (Kakegawa Fauna) Cold Water Fauna at __ © Coastal water associations o Offshore water associations (Omma - Manganji Fauna) Z + Embayment associations te = (Tatsunokuchi Fauna) 7a 36 39 7 Warm Water S : —— — Cold Water 9) Makers se} : © Presumed Land Area 36 | Inland Lakes Figure 5 Distribution of the Pliocene and early Pleistocene molluscan faunas and presumed paleogeography of Japan during the Pliocene and early Pleistocene. Numerals indicate the fossil localities mentioned in the text; 36: Shimajiri in Okinawa-jima; 37: Kagegawa; 39: Choshi; 40: Omma 42: Futaba; 493: Sendai; 46: Sannohe; 47: Tsugaru; 50: Cheju Island in Kanazawa; 44: Manganji; 48: Takikawa; 41: Higashiyama; 45: Futatsui; 49: Honbetsu; An inner sublittoral coastal water association is known in the marginal and basal medium-grained sandstone facies of the Kakegawa Group. It is composed mainly of sandy bottom dwellers intermingled with the species from other habitats. The association is characterized by the common occurrence of Anadara castellata, Venericardia panda, Amussiopecten praesignis, Glycymeris nakamurat, Turri- tella perterebra, and Umbonium suchtense. The species are peculiar to the Kakegawa Fauna, and the occurrence of one of these species is thought to be indicative of the dis- tribution of the fauna. Lateral change of offshore molluscan fauna correspond- ing to the lithofacies changes in the Kakegawa Group have been noted by CuinzE! & AOSHIMA (1976). In the offshore area of medium-grained sand, there is a belt of fine-grained muddy sandstone containing outer sublittoral muddy bot- tom mollusks such as Venus foveolata, Glycymeris rotunda, Nemocardium samarangae, and Siphonalia spadicea. The association from the coarse-grained siltstone is dominated by gastropod species, now living in the uppermost bathyal zone, such as Nassaria magnifica, Makiyamaia coreanica, Fulgoraria hirasei, and Lunatia plicispira. The offshore Vol. 21; No. 2 THE VELIGER Page 163 Ce eee eee anes eee nemo emma fine-grained siltstone contains scattered Limopsis tajimae, a species characteristic of the present-day upper bathyal, associated with Neilonella coix, Malletia inaequilateralis, and gastropods in common with the coarse-grained silt- stone facies. Associations similar to those in the Kakegawa area are distributed along the Pacific coast of Southwest Japan southward to the Ryukyu Islands. The coastal water asso- ciations have not been found on Okinawa-jima and other nearby islands (MacNErL, 1960). A bathyal molluscan fauna, representing the deepest association among the known Kakegawa Fauna, is reported from Okinawa-jima (Loc. 36, Nona, 1976). It includes Neilonella japonica, Bathyarca sibogai, Turricula aeola, and Benthovoluta hil- gendorfi. The northeastern limit of distribution of the shallow water association is found in the central part of the Boso Peninsula, southern Kanto (Loc. 38). The Pliocene and Early Pleistocene molluscan fauna of the Japan Sea coast of Honshu has been called the Omma- Manganji Fauna. The general character of the fauna is cold water, composed of species now living in the areas under the influence of the cold Oyashio Current, and by extinct species. Three principal associations are recognized in the Omma-Manganji Fauna: coastal water sandy bottom associations, coastal water gravelly bottom associations, and offshore muddy bottom associations. The typical composition of the shallow sandy bottom associations was described in the Futatsui area, northern Honshu (Loc. 45, CuinzEI, 1973), where two types of asso- Ciations are recognized in fine-grained sandstone. The as- sociation from the lower horizon is characterized by the predominance of Limopsis tokaiensis, Acila nakazimai, Venericardia ferruginea, and Turritella saishuensis. The association presumably lived in deeper water than the over- lying Anadara-Mercenaria association, as it is found in an intermediate horizon between the offshore muddy associa- tion and the Anadara-Mercenaria association. The Ana- dara-Mercenaria association, found in the upper horizon, is composed mainly of Turritella saishuensis, Macoma tokyoensis, Anadara amicula, Mercenaria stimpsoni, Dosi- nia japonica, Mya cuneiformis, Thracia kakumana, and Felaniella usta. The fauna in gravel or coarse-grained sandstone is char- acterized by the common occurrence of Astarte borealis, Glycymeris yessoensis, Chlamys cosibensis, Epitonium spp., Ocenebra spp., and Boreotrophon spp., e.g., in the Manganji area (Loc. 44, OruKa, 1936) and in the Nishi- Tsugaru area (Loc. 47, Iwai, 1965). It is usually inter- mingled with the species probably derived from other facies. These associations are found separately, or intermingled with each other, in Pliocene and lower Pleistocene sandy sediments in many other areas along the Japan Sea coast. In the Omma area near Kanazawa (Loc. 40), one of the typical localities of the fauna, fossils are found as shell beds composed mainly of the species in common with, or closely related to, those in the Futatsui area. They are intermixed with those from other facies (OGASAWARA, 1977). There are some indigenous species such as Mizuhopecten tokyoensis hokurikuensis, Anadara ommaensis, and Pseudamiantis tauyensis. The offshore muddy fauna in the Futatsui area is repre- sented by Nuculana robait, Macoma calcarea, Serripes groenlandica, Conchocele bisecta, Turritella nipponica, Buccinum tsubai, and Rectiplanes sadoensis (CHINZEI, 1973). These species are found sporadically in grey silt- stone. In general, the offshore muddy association in the Omma-Manganji Fauna is characterized by the dominance of gastropods such as Admete, Antiplanes, Propebela, and other buccinid and turrid species. As the Pliocene and the lower Pleistocene strata on the Japan Sea coast areas were accumulated at the last stage of reclamation of the Neogene basins, the offshore fauna tends to occur in the lower horizon, and is replaced upward by the shallow water associations as observed in the Fu- tatsui area. The age of appearance of the shallow water association may differ in places, it is earlier in the marginal areas and later in the central parts of the basin. The westernmost distribution of the Omma-Manganji Fauna is on Cheju (Saishu) Island (Loc. 50), southern Korea, from which T urritella satshuensis was described by YOKOYAMA (1923). In this locality, T. satshuensis is asso- ciated with Venericardia ferruginea, Chlamys cosibensis, Mizuhopecten tokyoensts, and some other mollusks. No further information is available on the fauna associated with T. saishwensis on Cheju Island. The distribution of the Omma-Manganji Fauna is thought to be confined to the Japan Sea coast area. However, shallow sandy mollusks from the Futaba area (Loc. 42), south of Sendai, may be re- ferred to the Omma-Manganji Fauna (Hayasaka, 1956). Also, an offshore muddy association similar to that in the Omma-Manganji Fauna is recorded in the Choshi area (Loc. 39), eastern Kanto (OzaAKI, 1958). It should be noted that the elements of the warm Kake- gawa Fauna, Glycymeris nakamurai and Umbonium su- chiense, were reported in association with the Omma- Manganjian shallow water sandy mollusks from the Higa- shiyama area, Niigata Oil Field (Loc. 41, KANEHARA, 1940). Occurrence of the warm water Kakegawa elements on the Japan Sea coast of central Honshu indicate a marine connection with the Pacific side. Page 164 The embayments formed during the minor late Plio- cene transgression were inhabited by a fauna of brackish and shallow marine aspect. The fauna, called the Tatsu- nokuchi (Tatunokuti) Fauna, is characterized by bivalve species indigenous to these embayments, particularly by a hump-backed pectinid, Fortipecten. It is typically found in the Sendai Basin (Locs. 30 and 43), and is known from the Sannohe area in northern Honshu (Loc. 46), and the Takikawa (Loc. 48), Honbetsu (Loc. 49) and other areas in northern and eastern Hokkaido. In the Sendai basin, Fortipecten takahashii is found in poorly sorted medium- to coarse-grained sandstone in association with Pseudami- antis sendaicus, Anadara tatunokutiensis, Dosinia tatuno- kutiensis, Peronidia sp., Neverita kiritaniana, and other species. Although the association represents the Tatsuno- kuchi Fauna, it is found in restricted parts of the restored bay (CHINzEI & Iwasak1, 1967). The inner half of the deep embayment is an area of dark grey sandy siltstone, in which large banks of Crassostrea gigas are predominant; the cen- Mo.tuscan AsSocIATIONS Batillaria Crassostrea Pseudamiantis - Anadaza Felaniella Macoma - Mya Ooseteec LITHOPACIES — Grey mud — Black mud Muddy sand Gravel Figure 6 Distribution of the coastal water associations in the late Pliocene embayment of the Sendai Basin. Thick line indicates the presumed coastline. Locality 30: Ichinoseki; Locality 43: Sendai. Redrawn from Cuinze1 & IwasaKi (1967) THE VELIGER Vol. 21; No. 2 tral part of the bay is occupied by a Macoma-Mya associa- tion composed of Macoma tokyoensis, Mya japonica, and Lucinoma annulata, found sporadically in grey massive siltstone (Figure 6). The shallow water association in the Sannohe area (Loc. 46) is peculiar in the combined occurrence of the Tatsu- nokuchian and Omma - Manganjian species (CHINZEI, 1961). The association from poorly sorted medium-grained sandstone is characterized by Anadara tatunokutiensis, Peronidia protovenulosa, Mercenaria stimpsoni, Spisula kurthoma, and Fortipecten kenyoshiensis. An offshore muddy association of the Omma-Manganji type is found in the central and deeper part of the Sannohe Basin. Forti- pecten takahashit is associated with Turritella fortilirata, Spisula voyt, Macoma tokyoensis, Yoldia macroshema, An- adara “‘trilineata;’ and Mya japonica in the Takikawa area (Loc. 48), central Hokkaido. The fauna is found in the innermost part of the embayment. The association char- acterized by Fortipecten takahashii is commonly found in the Plio-Pleistocene sandy facies of northern and eastern Hokkaido. The shallow sandy association of Fortipecten takahashii 1s dominated by Anadara, Dosinia, Peronidia, and Pseuda- miantis or Mercenaria in the Sendai and other areas. The principal generic composition is comparable to that of the shallow sandy association of the Omma-Manganji Fauna in Futatsui and other areas, although there are no species in common. The Anadara-Dosinia association of the Tatsu- nokuchi and the Omma-Manganji faunas occupied a sim- ilar biotope in the different basins, but they are thought to have been separated zoogeographically from each other. PALEOECOLOGICAL NOTES ON THE JAPANESE NEOGENE MOLLUSCAN FAUNAS Most associations represent original species associations. This is confirmed by observations of autochthonous fossil occurrences, 1.e., individuals that lived together and were buried at their living places. Some other associations do not show positive evidence of in situ preservation, but identical species associations have been reported from many localities. Their compositional identity suggests that the observed species composition is original. Such an asso- ciation represents part of the original benthic community in the sense of PETERSEN (1913). Similarity of species composition is remarkable among the shallow water associations of different ages, especially among those of the embayments (Figure 7). Associations characterized by potamid gastropods and oysters of the genus Crassostrea are known from all 4 faunas of different Vol. 21; No. 2 THE VELIGER Page 165 Recent, Akkeshi Bay (Hokkaido) pry ie Crassostrea Batillaria Ocenthra “epee ALP wmwmm oyunu ce “ne ae oe wie St Onna an a ae iy TH TPS Q 0 ay ™ 6 rr 0= prey Ky Low Tide qT oN i 6} & 4 =-— Laminaria oes Macoma Mya eyes Tapes on Cryptonatica ¥ DS 4 _ Mizuhopecten Exocallista’ OQ Cy ee Late Priocene, Sendai Basin * Clinocardium Sean's Gane NER =-vtogtto Fortipecten fee Mya Late Miocene, Tanagura area Cerithium Crassostrea SS = TE, y ee ae hove lignite deposition Macoma Pee S; OOo Me BG DoS Chlamys Dosinia yw Turritella Vasticardium yt g : Polinices ©. & a Potting Waid: Se pone ei Pseudamiantis O Meecin®) @ ‘ 0x ° . \. Lucinoma Earty Mippte Miocene, Kadonosawa area Cultellus Vicarya ie ae Saxolucina “Siphonalia’ ste Bs 7 a 0 g Ta —~ Crassostrea gravitesta J u ae — LO low ae 00a. ead is renee gen? 68st a izuhopecten 4 Polinices : “6 be to OK wee Sars a ee cw Ae Anadara Compsomyax @ eee a gy : "eS Se = | Soletellina an Aa BS ip -° ee Panopea Dosinia ; yeas L —-G ~ fe) Nciocardiam Y 1: acinpma Gg Gg > Macoma Figure 7 Coastal water molluscan associations of the early middle Miocene Kadonosawa Fauna (Kadonosawa Basin, Locality 17), the late Miocene Shiobara Fauna (Tanagura area, Locality 27), and the Pliocene Tatsunokuchi Fauna (Sendai Basin, Locality 43). Recent cold water associations in Akkeshi Bay and adjoining brackish water Akkeshi Lake, eastern Hokkaido, are also shown for com- parison. ages. They are found invariably in mud or muddy sand of the marginal part of a sedimentary basin or the innermost part of an embayment. They may represent intertidal com- munities. Shallow water sandy facies were populated by associations dominated by Dosinia, Anadara, Cardium and other shallow-burrowing suspension feeders. They are commonly associated with carnivorous naticid gastropods. The species diversity as well as population density in this facies are the highest of all of the Neogene molluscan asso- ciations. The high proportion of burrowing suspension feeders corresponds with that of the present-day sandy bot- tom fauna (SANDERS, 1958; K1kuUCHI, 1977). The shallow muddy bottom associations are dominated by Macoma and Page 166 THE VE LIGER Vol. 21; No. 2 Lucinoma in common besides other species peculiar to each association. They are rich in deposit feeding forms. Naticids are uncommon in these associations. Table 1 shows a comparison of the principal constituents of repre- sentative shallow water and embayment associations. These similarities of composition are indicative of ana- logous ecologic characters of the associations. The ecolog- ically congruent relationships of the associations were first discussed by CHINZEI & IWASAKI (1967) for the shallow sea faunas in northern Honshu. They called the relationship chronologically parallel comparing it with geographically parallel ones seen in the Recent benthic communities (TuHorson, 1957). Congruent relationships are not clear among the offshore associations in the Japanese Neogene. Species are usually replaced, between the congruent associations of different ages, by different species belong- ing to the same genus or ecologically allied genera. The replacement of species may be the consequence of evolu- tionary change within the same genus, as well as new immi- gration from the south to the north. For example, species of Anadara that lived in Northeast Japan from the late Miocene through the early Pleistocene are probably the descendants of species that invaded Japanese waters from the south during early middle Miocene time. The species found in the Kakegawa Fauna, however, is considered to be an immigrant from the south during Pliocene. The coastal water mollusks living in present-day Japanese waters may be the descendants of species that lived in coastal waters during Neogene and partly species that im- migrated from the south during the late Pleistocene and post-glacial ages. Table 1 Species composition of representative coastal water associations in the same or ecologically allied species among the associations of the Neogene molluscan faunas in Japan. Note the occurrence of different ages. Age (Example) Early Miocene Early Middle Miocene (Loc. 2, Kottoi; subtropical) | (Loc. 17, Kadonosawa; subtropical) *(Loc. 12, Mizunami) Presumed Environment Tidal flat (muddy sand or sandy mud facies) Batillaria takeharai | Batillaria yamanarit Vicarya callosa japonica _Macoma cf. incongrua | Soletellina minoensts | | Cyclina japonica iiss | Crassostrea gravitesta Compsomyax tizukai Panopea kanomataza- waensis Intertidal (muddy or sandy facies) Crassostrea sp. Level bottom Dosinia chikuzenensis | Dosinia nomurat (sandy facies) Glycymerts cisshuensis | Glycymeris cisshuensis | Tapes stratoriensts Compsomyax tizukai Pitar matsumotot Sollen connectens Anadara ninohensis Clinocardium shinjiense Solen connectens | Panopea kanomataza- waensts Euspira meisensis Level bottom (muddy facies) Angulus maximus Venericardia subnip- pontica *Macoma optiva Venericardia siogam- ensis Lucinoma acutilineatum Cultellus izumoensis Cultellus izumoensis Macoma incongrua Dosinia kaneharat D. japonica Protothaca tateiwat Mercenaria yokyamat Anadara ninohensis Laevicardium shioba- Panopea japonica Nevernita kiritantana Macoma optiva |Lucinoma annulatum Late Miocene Pliocene — Living Early Pleistocene (Loc. 27, Tanagura; | (Loc. 43, Sendai; (Akkeshi, Hokkaido; temperate) temperate) cold temperate) Cerithium kobelti Batillaria multiformis | Batillaria cumingt Macoma incongrua | Mva japonica Tapes japonica Muacoma incongrua Mya japonica | Crassostrea gigas Crassostrea gigas Tapes japonica Mya japonica Crassostrea gigas Disinia tatunokutiensis Glycymeris cisshuensis | Glycymeris gorokuensis | Glycymeris yessoensts Ezocallista brevisiphonata Pseudamiantis pinguis | Pseudamiantis sendaicus Anadara tatunokutiensis Clinocardium pseudo- fastosum Panopea japonica Clinocardium califor- niense rense Neverita kiritaniana Cryptonatica janthostoma Macoma tokyoensis Lucinoma annulatum Cultellus izumoensts Vol. 21; No. 2 SUMMARY or ZOOGEOGRAPHIC CHANGES oF THE JAPANESE ISLANDS purinc NEOGENE as VIEWED FROM BENTHIC MOLLUSKS Distributions of the Neogene molluscan faunas in space and time are summarized in Figure 8. The boundaries of the faunas are greatly simplified, and the chronologic po- sitions of the early Miocene faunas are tentative. The predominance of warm water faunas in early middle Miocene time is the most pronounced event in the faunal history of the Japanese Neogene mollusks. At this time the convergence between warm and cold currents, the subtrop- ical front. was most probably located as far north as central Hokkaido. A major part of Japan was inhabited by the tropical and subtropical coastal water faunas. The main stream of the warm water current probably passed along Province Japan Sea Coast Pacific Coast of of SW Japan Southwest Japan Omma - Manganji Fauna (OSW - Kakegawa Fauna (OSW - CW) ‘al ad = Z <2} (2) fe) ~ — a ca 1 Prer ee ? Ashiya Fauna (CW, Emb.) ete oie dis de cece DY Cis THE VELIGER Page 167 the Japan Sea side of the Islands, because the tropical mol- lusks are known only from the Japan Sea coast and adjoin- ing areas in western Japan. The vertical structure of water masses in the early middle Miocene was possibly different from that of present-day Japanese waters. The undercur- rent of cold water reached down to central Honshu along the Pacific coast, approximately at the same position as today. Perhaps the early middle Miocene warm surface current in the area now constituting Japan was thinner than the present Kuroshio Current, thus allowing a deep, cold water tongue to advance far south of and beneath the subtropical front. Figure 8 (below) Chronologic and geographic distributions of the Japanese Neogene and Pleistocene molluscan faunas. osw: offshore water associa- tions; cw: coastal water associations; emb: embayment and brack- ish water associations. Northeast Japan North Honshu Hokkaido Oyashio Fauna reer @ Takigawa F. auna (Emb.) CW) (Emb.) Yama Fauna — Shiobara Fauna (OSW) (CW) (poor in molluscs) = Chikubetsu Kadonosawa Fauna (CW, Emb.) Sy Fauna (CW) im Asahi Fauna (CW) (Barren of molluscs) Limit of tropical-subtropical faunas oh ob Page 168 THE VELIGER Vol. 21; No. 2 Duration of pronounced warming was probably short, around 1 or 2 my, apparently within Blow’s planktic fora- miniferal Zones N8 and Ng. The beginning of the warm period is uncertain. It might have been contemporaneous with the start of the middle Miocene transgression. Data are too scanty to obtain a clear image of zoogeography dur- ing the early Miocene, and the transition from the early Miocene faunas to those of early middle Miocene is ob- scure. The early middle Miocene period of warming has been recorded from the northern and eastern coast of the Pacific (e.g., ALLISON, 1976; AppICOTT, 1969), as well as from the South Pacific (HORNIBROOK, 1977) and from the Antarctic Sea (SHACKLETON & KENNETT, 1975). This indicates that the faunal episode in Japan was induced by global activa- tion of warm current systems. The end of the warm period is seemingly abrupt as far as the benthic faunas are concerned. In the late Miocene no apparent subtropical species has been reported from the entire Japan Sea coast area. The late Miocene faunas in the Japan Sea areas are composed exclusively of the cold water species, elements of the subarctic and coastal waters of the temperate region. This is a sharp contrast to the tropical or subtropical nature of the early middle Miocene faunas in these areas. The switchover from warm to cold water happened during the middle Miocene, around 14 my ago, as revealed by an abrupt change of benthic foraminiferal fauna in the Japan Sea areas (e.g., Tar, 1963; MatyA, 1977). Tar (1963: 4) called the horizon of ‘change as ‘‘Foram. Sharp Line’’ The sharp change in the Japan Sea area might be the result of closure of the Korean Strait, rather than abrupt global change of climate. The benthic molluscan faunas in the Japan Sea areas have maintained their cold water nature from the late Miocene through the beginning of the early Pleistocene. Apparent warm water species reappeared in the Japan Sea areas during the early Pleistocene and later as exemplified by the occurrence of Conus and other warm water species from the upper part of the Omma Formation (OGAsAWaRA, 1977). Koizumi (1977) noted the occurrence of a warm water diatom flora in the late Miocene from a piston-core sample obtained in the central part of the Japan Sea. He considered that the Sea was connected with the Pacific both to the south and to the north. The only indication of this warming found on land is the occurrence of Nautilus izu- moensis in the upper Miocene of the Sanin area (Loc. 24) and a few other localities. The convergence of cold and warm waters in the late Miocene was probably located in Kanto, central Honshu, at approximately the same position as today. After this, no marked shift of the position of convergence is detected through the molluscan faunal sequence. The convergence has remained relatively stationary during the late Neogene and the early Pleistocene. Oxygen paleotemperature anal- ysis shows that the thermal structure of the warm water in Plio-Pleistocene time was comparable to that of the pres- ent-day Kuroshio and associated water (CHINZEI & Ao- SHIMA, 1976). ACKNOWLEDGMENTS Professor Tetsuro Hanai and my colleagues in the Univer- sity of Tokyo, and Dr. Yasuhide Iwasaki of Kumamoto University gave valuable suggestions and advice on various aspects of paleontologic problems. Comments on the bio- geography and ecology of present Japanese waters were made mainly by Professor Masuoki Horikoshi of the Uni- versity of Tokyo. Discussions with many other friends were also stimulating for me. The manuscript was reviewed by Dr. Warren O. Addicott of U.S. Geological Survey, Menlo Park, Professor T. Hanai, and Dr. J. A. Grant-Mackie of the University of Auckland, New Zealand. My deep appre- ciation is due to these persons for their kind help. Literature Cited [J: in Japanese; J, E: in Japanese with English abstract] AppicoTT, WARREN OLIVER 1969. ‘Tertiary climatic change in the marginal northeastern Pacific Ocean. Science 165: 583 - 586; 3 text figs. A.Lison, RicHARD Casz 1976. Late Oligocene through Pleistocene molluscan faunas in the Gulf of Alaska region. Abstr. Pap., First Internat. Congr. Pacif. Neo- gene Stratigraphy. Tokyo, Japan, May 16-21, 1976: 10-13. Repr. Proc. First Internat. Congr. Pacif. Neog. Stratigraphy 313-316; 1 text fig., 1 table. Tokyo, Japan, 1977 Asano, KryosH1 # Kotora Hatat 1967. Micro- and macropaleontological Tertiary correlations within Japanese Islands and with planktonic foraminiferal sequences of for- eign countries. In K. Hartar (ed.): Tertiary correlation and cli- matic changes in the Pacific. 11th Pacif. Sci. Congr. Symp. 25, Tokyo: 77-87 Cuinzer, KrvoTaKa 1961. Molluscan fauna of the Pliocene Sannohe Group of Northeast Honshu, Japan: 2. The faunule of the Togawa Formation. Journ. Fac. Sci., Sec. 2, Univ. Tokyo 13 (1): 81-131; 4 pits. 1963. Notes on historical change of Neogene molluscan assemblages in Northeast Japan. Kaseki (Fossils), Palaeont. Soc. Japan 5: 20-26 1973. eae molluscan fauna in the Futatsui area of northern Akita, Japan. Trans. Proc. Palaeont. Soc. Japan, N.S. go: 81-94; pit. 14 Cuinzezt, Krvoraka & MutsuHARU AOSHIMA 1976. | Marine thermal structure of the Plio-Pleistocene warm water in central Japan. Journ. Fac. Sci., Sec. 2, Univ. Tokyo 19 (3): 179 - 203 Cuinzet, Krvotaka & YaSuHmE IwasAkI 1967. Paleoecology of shallow sea molluscan faunas in the Neogene deposits of Northeast Honshu, Japan. Trans. Proc. Palaeon. Soc. Japan, N.S. 67: 93 - 113 Guapenxov, Yuru Bortsovich 4 1974. The Neogene period in the subarctic sector of the Pacific. In Yvonne Herman (ed.), Marine geology and oceanography of the Arctic seas. Springer Verlag, New York: 271-281; 3 text figs. ; 3 tables Vol. 21; No. 2 THE VELIGER Page 169 HayasaKa, SHozo 1956. Pliocene Mollusca from the Futaba district, Fukushima Prefec- ture, Japan. Saito Ho-on Kai Mus. Res. Bull. 25: 13-20; pit. 2 1957. Miocene marine Mollusca from the Kurosawa Formation in Akita and Iwate Prefectures, Japan. Saito Ho-on Kai Mus. Res. Bull. 26: 25 - 30 1969. Molluscan fauna of the Kukinaga Group in Tane-ga-shima, South Kyushu, Japan. Rept. Fac. Sci. (Earth Sci. & Biol.), Kago- shima Univ. 2: 33-52; 3 plts. Hornisrook, N. vz B. 1977. The Neogene (Miocene-Pliocene) of New Zealand. Proc. 18t Congr. Pacif. Neogene Stratigr., Sci. Council & Geol. Soc. Japan: 145-150 IxeBE, Nosuo 1954. Cenozoic biochronology of Japan. (G), Okasa City Univ. 1: 73 - 86 Ixese, Nosuo, Yoxicu: TAKAYANAGI, Manzo Criji & Krvotaka CHINZEI 1972. Neogene biostratigraphy and radiometric time scale of Japan; an attempt at intercontinental correlation. Pacif. Geology 4: 39 - 78 INncLE, James CuHeEsNeY, Jr. # Robert E. Garrison 1976. Origin, distribution, and diagenesis of Neogene diatomites around the North Pacific rim. Abstr. 18t Congr. Pacif. Neogene Stratigr., Sci. Council & Geol. Soc. Japan: 98 - 100 Iroicawa, JUNJ1 1960. Paleoecological studies of the Miocene Mizunami Group, cent- ral Japan. Journ. Earth Sci., Nagoya Univ. 8 (2): 246-300 1974. Fossil molluscan assemblages. In J. ITo1iaawa, H. SHIBATA & H. NisHimorto, Fossil shells from the Mizunami Group. Bull. Mizunami Fossil Mus. 1: 196 - 203 (J) Iroicawa, Junj1 & Hirosui SHIBATA 1973. Paleoenvironmental change and correlation based on molluscan assemblages. Mem. Geol. Soc. Japan 8: 125 - 136 (J, E) IWASAKI, YASUHIDE 1970. The Shiobara-type molluscan fauna; an ecological analysis of fossil molluscs. Journ. Fac. Sci. Sec. 2, Univ. Tokyo 17 (3): 351-444; 7 pits Iwal, TAKEHIKO 1965. The geological and paleontological studies in the marginal area of the Tsugaru Basin, Aomori Prefecture, Japan. Bull. Educ. Fac., Hirosaki Univ. 15: 1 - 68; pits. 12-20 Kanenara, Kinj1 1940. Neogene fossils from south Echigo. Japan 27 (2): 1- 19; 5 plts. Kanno, SABURO 1960. Paleontology. In The Tertiary system of the Chichibu Basin, Saitama Prefecture, central Japan, prt. 2: Japan Soc. Promot. Sci., Tokyo: 123 - 396; plts. 31-51 Kanno, Sapuro & KyuyA Matsuno 1960. Molluscan fauna from the “Chikubetsu Formation,” Hokkaido, Japan. Journ. Geol. Soc. Japan 66 (772): 35-45; pits. 4, 5 Kanno, Sapuro « HisasH1 OGAWA 1964. Molluscan fauna from the Momijiyama and Takinoue District, Hokkaido, Japan. Sci. Rept. Tokyo Kyoiku Daigaku, Sec. C. 81: 269 - 294; 4 plts. Kanno, Sasuro, SakazE Ouara « HitosHi KaITeYA 1968. The “Asahi Fauna” from the Miocene formation developed near the Asahi Coal-mine. Iwamizawa City, Hokkaido. Sci. Rept. Tokyo Univ. Educ. Sec. C 10 (94): 1-14; 2 pits. Kixucal, Taryjr 1977. Ecological distribution of macrobenthos and shell remains off Tsuyazaki, Fukuoka Prefecture. Benthos Res. 13/14: 7-16 (J) Kim, Bono Kyun, Hirosu: Nova « SuN Yoon 1974. Molluscan fossils from the Miocene Eoil Formation, Gampo and Ulsan Districts, southeastern side of Korea. Trans. Proc. Pa- laeont. Soc. Japan N. S. 93: 266 - 285; plts. 38, 39 Kosayasui, TeucHi a Masuox1 HorixosHr 1958. Indigenous Aturia and some tropical gastropods from the Mio- cene of Wakasa in West Japan. Japan. Journ. Geol. Geogr. 29 (1/3): 45-545 plts. 4, 5 Koizumi, ITaru 1977. Deep sea sediments and the history of Japan Sea. Iwanami Book Co., Tokyo 47 (1): 45°51 (J) Kotaxa, Tamio 1958. Faunal consideration of the Neogene invertebrates of northern Honshu, Japan. Saito Ho-on Kai Mus. Res. Bull. 27: 38 - 44 1959. The Cenozoic Turritellidae of Japan. Sci. Rept. Tohoku Univ. (2) 31 (2): 1- 1355 15 plts. MacNeiz, Francis STEARNS 1960. Tertiary and Quaternary gastropods of Okinawa. U.S. Geol. Surv. Prof. Paper 339: 1 - 148; 21 plts. Journ. Inst. Polytech. Bull. Imp. Geol. Surv. Kagaku, Marya, Sz1JuRO 1977. Late Cenozoic planktonic foraminiferal biostratigraphy of the oil-field region of Northeast Japan. Prof. N. Ikebe Memorial volume Osaka (in press) (J, E) MakryvaMa, Jiro 1926. Tertiary fossils from North Kankyo-do, Korea. Mem. Coll. Sci., Ser. B, Kyoto Imp. Univ. 2 (3): 143-160; plts. 12, 13 1931. Stratigraphy of the Kakegawa Pliocene in Totomi. Mem. Coll. Sci., Ser. B, Kyoto Imp. Univ. 7 (1): 1-53 1934. The Asagaian molluscs of Yotukura and Matchgar. Mem. Coll. Sci., Ser. B, Kyoto Imp. Univ. 10 (2): 121-167; plts. 3-7 1936. The Meisen Miocene of North Korea. Mem. Coll. Sci., Ser. B, Kyoto Imp. Univ. 11 (4): 193 - 228; plts. 4, 5 Masupa, K.6icHIR6é 1962 . Notes on the Tertiary Pectinidae of Japan. Sci. Rept. Toho- ku Univ. (2) (Kon’no Mem. vol.) 5: 159 - 193; 9 text figs. 1966. Molluscan fauna of the Higashi-Innai Formation of Noto Pen- insula, Japan; 1. A general consideration of the fauna. Trans. Proc. Palaeont. Soc, Japan, N.S. 63: 261 - 293 1973. Molluscan biostratigraphy of the Japanese Neogene. Mem. Geol. Soc. Japan 8: 107-120; 2 plts.; 1 text fig. (J, E) Nopa, Hirosxi 1966. The Cenozoic Arcidae of Japan. (2) 38 (1); 1-161; 14 plts. 1976. Preliminary notes on the bathyal molluscan fossils from the Shin- zato Formation, Okinawa-jima, Okinawa Prefecture, Southwestern Japan. Ann. Rept. Inst. Geosci., Univ. Tsukuba 2: 40-41 Nomura, SITIHEI 1935. On some Tertiary Mollusca from Northeast Honshu, Japan: pt. 2. Fossil Mollusca from the vicinity of Ogino, Yama-Gun, Hukushima- Ken. Saito Ho-on Kai Mus. Res. Bull. 5: 101 - 125; plst. 5-7 Ooasawara, KeNsHIRO 1977. Paleontological analysis of Omma Fauna from Toyama-Ishikawa area, Hokuriku Province, Japan. Sci. Rept. Tohoku Univ. (2) 47 (2): 43-156; plts. 3-22 Owara, SAKAE & SABURO KANNO 1973. Mid-Tertiary marine molluscan faunas from the Uryu Coai-field of central Hokkaido, Japan. Sci. Rept. Tohoku Univ. (2) Spec. vol. 6: 125-135 Oxamoto, Kazuo 1970. Tertiary formations in the area around Kottoi-harbor, Hohoku- machi, Toyoura-gun, Yamaguchi Prefecture, with reference to the mol- luscan fossil assemblages and sedimentary environment of the Hioki Group. Journ. Geol. Soc. Japan 76 (5): 235-246 (J, E) OxutTAni, TAKASHI 1972. | The probable subarctic elements found in the bathyal megalo- benthos in Sagami Bay. Journ. Oceanogr. Soc. Japan 28 (3): 95 - 102 OruKa, YANOSUKE 1934. Tertiary structures of the northwestern end of the Kitakami Mountainland, Iwate Prefecture, Japan. Bull. Earthq. Res. Inst., Univ. Tokyo 12 (3): 566-638; plts. 44-51 1936. Pliocene Mollusca from Manganzi in Kotomo-mura, Akita Pref, Japan. Trans. Proc. Palaeont. Soc. Japan. Old Ser. 4 (in Journ. Geol. Soc. Japan 43): 726-736; pits. 41, 42 1939. Tertiary crustal deformations in Japan; with short remarks on Tertiary palaeogeography. Jubl. Publ. Commem. Prof. H. Yabe’s Goth Birthday: 481 - 519 uh 1941. Neogene fossil fauna between Honjo and Kurosawajiri. Journ. Japan Assoc. Petrol. Technologists 9 (2): 147-157 (J) Oyama, Katura : ; 1950. Studies of fossil molluscan biocoenosis, No. 1; biocoenological studies on the mangrove swamps, with descriptions of new species from Yatuo Group. Geol. Surv. Japan, Rept. 132: 1-16; 3 pits. Oza, HirosH1 3 1958. Stratigraphical and paleontological studies on the Neogene and Pleistocene formations of the Choshi District. Bull. Natl. Sci. Mus. 4 (1): 1-182; 24 ple. Petersen, C. G. J. a 1913. Valuation of the sea II: The animal communities of the sea- bottom and their importance for marine zoogeography. Rept. Danish Biol. Stat. a1: 1-44; 6 plts., 3 charts Sanpers, Howarp L. a ! i 1958. Benthic studies in Buzzards Bay; I, animal-sediment relation- ships. Limnol. Oceanogr. $(3): 245-258 SHackeLTon, NicHoxas J. & James P Kennett — comer 1975- Paleotemperature history of the Cenozoic and the initiation of Antarctic glaciation: oxygen and carbon isotope analyses in DSDP sites 277, 279, and 281. In J. P Kennett, R. E. Hourz et al., Init. Rept. Deep Sea Drill. Proj., Washington, 29 (17): 743 - 755 Sci. Rept. Tohoku Univ. Page 170 THE VELIGER Vol. 21; No. 2 SHIKAMA, TOKIO 1973. Molluscan assemblages of the basal part of the Zushi Formation in the Miura Peninsula. Sci. Rept. Tohoku Univ. (2) Spec. vol. 6: 179-204; plts. 16, 17 SuHixaMa, Toxio « Tomoxi Kasz 1976. Molluscan fauna of the Miocene Morozaki Group in the southern part of the Chita Peninsula, Aichi Prefecture, Japan. Sci. Rept. Yokohama Natl. Univ. Sec. 2, 23: 1 - 25; 2 pits. SuutTo, Tsucio 1961. Palaeontological study of the Miyazaki Group; a general ac- count of the faunas. Mem. Fac. Sci. Ser. D., Kyushu Univ. 10 (2): 73 - 206; pits. 11-13 1963. Geology of the Nichinan area with special reference to the Takachiho Disturbance. Sci. Rep. Fac. Sci. (Geol.), Kyushu Univ. 6 (2): 135 - 166; plts. 14-18 (J, E) SuHutTo, Tsucio & NARUMI SHIRAISHI 1971. A note on the community-paleoecology of the Ashiya Group. Sci. Rept. Fac. Sci. (Geol.), Kyushu Univ. 10 (3): 253-270 (J, E) Tat, YOSHIRO 1963. Historical change of Neogene foraminiferal assemblages in the Setouchi-Sanin areas and Foram. Sharp Line. Kaseki (Fossils), Palaeont. Soc. Japan 5: 1-7 (J) TuHorson, GUNNAR 1957- Bottom communities (sublittoral or shallow shelf). In: J. W. HeporztH (ed.): Treatise on Marine Ecology and Paleoecology 1, Geol. Soc. Amer. Mem. 67: 461 - 534 Tsucut, Ryuicu1 1960. | Late Neogene sediments and molluscs in the Tokai region, with notes on the geologic history of Southwest Japan. Japan. Journ. Geol. Geogr. 32 (3, 4): 437-456 Tsuba, Karyu 1960. Paleo-ecology of the Kurosedani Fauna. Ser. 2, Niigata Univ. 3 (4): 171-203 Uozum1, Satoru 1962. Neogene molluscan faunas in Hokkaido (Part 1: Sequence and distribution of Neogene molluscan faunas). Journ. Fac. Sci. Ser. 4 4, Hokkaido Univ. 11 (3): 507-544 1966. Neogene molluscan fauna in Hokkaido; pt. 1, Description of the Asahi fauna associated with Mytilus tichanovitchi Makiyama, from Ikushunbetsu district, central Hokkaido. Journ. Fac. Sci. Ser 4, Hokkaido Univ. 13 (2): 119 - 137; plts. 9, 10 Uozumi, Satoru & Tsutomu Fujiz 1966. Neogene molluscan fauna in Hokkaido; pt. 2, Description of the Okushiri fauna associated with Vicarya, from Okushiri Island, South- west Hokkaido. Journ. Fac. Sci. Ser. 4, Hokkaido Univ. 1g (2): 139 - 163; plts. 11-13 YoxoyaMa, MATAjIRo 1920. _ Fossils from the Miura Peninsula and its immediate North. Journ. Coll. Sci., Imp. Univ. Tokyo 39 (6): 1 - 193; 20 plts. 1923. On some fossil shells from the Island of Saishu in the Straits of Tsushima. Journ. Coll. Sci., Imp. Univ. Tokyo 44 (7): 1-9; 1 plt. 1926. Tertiary Mollusca from Shiobara in Shimotsuke. Journ. Fac. Sci. Sec. 2, Imp. Univ. Tokyo 1 (4): 127-198; plts. 16-20 Journ. Fac. Sci. Vol. 21; No. 2 THE VELIGER Page 171 Late Oligocene Through Pleistocene Molluscan Faunas in the Gulf of Alaska Region BY RICHARD C. ALLISON Division of Geosciences, University of Alaska, Fairbanks, Alaska 99701 (2 Text figures) INTRODUCTION A NUMBER OF GULF OF ALASKA Tertiary formations con- tain fossil faunas of major importance to studies of North Pacific molluscan biostratigraphy and paleobiogeography (Figure 1). These faunas are, however, very poorly known. The interpretations offered here are based on faunal lists for each formation, but available space prohibits their in- clusion in this paper. It is my purpose to give a review of 9 Gulf of Alaska stratigraphic units and their molluscan faunas. I have treated these stratigraphic units and their faunas under “western Gulf of Alaska” and ‘northeastern Gulf of Alaska” headings because of significant differences in the faunas and geologic history of these two areas during Neo- gene time. The discussion deals primarily with the Neo- gene units of the Gulf of Alaska region, although two units, the Sitkinak Island Narrow Cape Formation, and the Poul Creek Formation, range down into the Paleogene. Quater- nary marine deposits are also considered. These North Pacific molluscan faunas are substantially different from those of the European stratotypes, a factor which makes epoch assignments difficult. I have attempted to correlate the Gulf of Alaska strati- graphic units with the provincial molluscan chronology of the Pacific Northwest Molluscan Province (ARMENTROUT, 1975; ADDICOTT, 1976), or with the late Pliocene to early Pleistocene marine transgressions of Beringia (Hopkins, 1967). The Pacific Northwest molluscan stages have been correlated with the benthic foraminifer stages of Cali- fornia, which have in turn been loosely correlated with the modern planktonic foraminifer zones by BERGGREN & VAN CovuvERING (1974). By this attenuated series of correlations I have attempted to recognize epoch boundaries in the Gulf of Alaska region. I expect substantial refinement of these correlations to result from future studies of western North American Cenozoic strata. Future research should permit definition of provincial molluscan stages for the Gulf of Alaska region, but present knowledge is insufficient for this purpose, even though a provincial chronology is needed. In the section that follows, I have given an abbreviated discussion of each Gulf of Alaska stratigraphic unit of late Paleogene to Recent age that bears a significant molluscan fauna. Not all Paleogene or Neogene formations of the area have been discussed. I have attempted to date each unit discussed, and have also offered inferences on water depths and sea temperatures as well as comments on the biogeographic affinities or faunal compositions for the mol- lusks. My use of European series/epoch terms is in the sense of BERGGREN & VAN COUVERING (1974). WESTERN GULF or ALASKA STRATIGRAPHIC UNITS The Narrow Cape Formation of Sitkinak Island: Approximately 210 meters of marine fossiliferous silt- stone crop out at the axis of a syncline located at the south- ernmost tip of Sitkinak Island, Alaska. These strata, which were referred to the Narrow Cape Formation by Moore (1969), conformably overlie the coal-bearing terrestrial Sitkinak Formation of Moor: (1969). Sitkinak Island Nar- row Cape Formation strata may be given a new formational name in the future because they differ from the type Nar- row Cape Formation strata of Kodiak Island in being gradationally conformable upon the underlying Sitkinak Formation, and in being older, as well as in lacking outcrop continuity. Moore (personal communication, 1976), how- ever, believes that these beds may represent the beginning of the same marine transgression that is represented at Nar- row Cape on Kodiak Island, and that the two stratal se- Page 172 TUGDAK & ISLAND > @& siTKINAK Fs ISLAND Sio THE VELIGER Vol. 21; No. 2 ¢ ISLAND GULF OF ALASKA Figure 1 Index Map of the Gulf of Alaska Region Showing Locations of Major Mollusk-Bearing Stratigraphic Units and the Geographic Locations of Places Referred to in the Text 1. Cold Bay 9. Milky River 2. Thinpoint Cove 10. Chirikof Island 3. Coal Bay 11. Chignik Bay 4- Popof Island 12. Black Peak 5. Zachary Bay 13. ‘Trinity Islands 6. Cape Aliaksin 14. Kodiak Island 7. Stepovak Bay 15. Wingham Island 8. Port Moller 16. Kayak Island quences should therefore be referred to the same forma- tional unit. Perhaps future knowledge of the offshore subsurface stratigraphy will clarify this point. To date, no faunal list has been published for the marine strata which crop out along the south coast of Sitkinak Island, but they contain a molluscan fauna now known from collections made by George Moore of the U.S. Geo- logical Survey and by John Armentrout of Mobil Oil Com- pany. This fauna, which consists of about 5», taxa, is not as diverse as that of the type Narrow Cape Formation of Kodiak Island. The Sitkinak marine strata belong to the Juanian Stage (Appicotr, 1976) [—Echinophoria apta zone of DuRHAM, 1944] of the provincial molluscan chronology (MacNEIL, 1965: 69). Assignment of these strata to the Echinophoria apta zone is confirmed by the presence of the zonal index fossil, E. apta. The E. apta zone corresponds to the upper 17. Suckling Hills 25. Yakataga Glacier 18. Grindle Hills 26. Samovar Hills 19. Kosakuts River 27. Karr Hills 20. Robinson Mountains 28. Pinnacle Hills 21. Guyot Glacier 29. Icy Point 22. Kulthieth Mountain 30. La Perouse Glacier 23. Chaix Hills 31. Topsy Creek 24. Munday Peak Zemorrian benthic foraminiferal Stage (DURHAM, 1944; ARMENTROUT, 1975; ADDICOTT, 1976). Several taxa which indicate that the Sitkinak marine strata are no older than the Juanian or E. apta zone are: Macoma calcarea (Gmelin), Macoma incongrua (von Martens) of KANNO (1971), Pitar angustifrons (Conrad), Spisula albaria (Con- rad), subsp.?, Spisula cf. S. hannibali (Clark & Arnold), Natica clausa (Broderip & Sowerby), and Polinices cf. P. galianoi Dall. Taxa not known to occur in strata younger than those of the E. apta zone also occur in the Sitkinak marine strata. These taxa are: Spisula cf. S. hannibalt, Bruclarkia cf. B. andersoni (Wiedey), Polinices ramonensis (Clark), and Priscofusus aff. P. stewarti (Tegland). BERGGREN & VAN COUVERING (1974) suggest that the late Zemorrian is approximately equivalent to planktonic fora- minifer zones N2/P21 through N4. If so, the Oligocene- Vol. 21; No. 2 THE VELIGER Page 173 Miocene boundary may fall high within the Echinophoria apta zone, more or less equivalent to the usage of West Coast benthic foraminifer workers. The early Miocene Pillarian molluscan Stage (early Saucesian benthic fora- minifer Stage) (Figure 2) is unrepresented in the known surface exposures of the western Gulf of Alaska. A few diagnostic taxa suggest that the Sitkinak Island Narrow Cape Formation strata were deposited in water no shallower than 18 m, and possibly no shallower than 37 m, and probably no deeper than 186 m or possibly no deeper than about 141 m. Kristin McDougall, of the U.S. Geolog- ical Survey (personal communication, Sept. 1976) reports the benthic foraminifers from this section to indicate prob- able depths between 100 and 300m. Taken together, the evidence suggests water depths during deposition were pri- marily in the outer neritic depth zone between 100 and 186 m. Water temperature during deposition of the late Oligo- cene Sitkinak Island Narrow Cape Formation was clearly temperate and cooler than that of the Miocene Narrow Cape Formation of Kodiak Island. Whether the water tem- perature was cool temperate like the present Aleutian- Gulf of Alaska region (HALL, 1964), or mild temperate like the present Oregonian province, is more difficult to assess. Both warmer and cooler faunal elements are present. In general, it seems probable that water temperature was slightly warmer than present water temperature at Sitki- nak Island, perhaps somewhat like that near the present cool temperate-mild temperate boundary. The fauna of the Sitkinak Island Narrow Cape Forma- tion contrasts strongly with that of the Narrow Cape For- mation of Kodiak Island. The presence of large Dosinia, Securella, Anadara (Anadara), large fulgorarids, and Ficus at Narrow Cape indicates substantially warmer water con- ditions, probably like those of the present warm temperate province. The Sitkinak Island Narrow Cape Formation mollusks are divided among stocks that had their principal centers of distribution, or regions of origin, along the Asiatic coast, along the Pacific Coast of North America, or to a lesser ex- tent in the higher latitude northern perimeter endemic region of the North Pacific. Of the 37 taxa which are ame- nable to this type of analysis, those with primary Asiatic affinities account for about 32%. Taxa with western North American affinities account for about 35% of the fauna, and species of endemic North Pacific origin account for about 30%. Fourteen percent of the fauna (included with the endemics) is composed of precursors of taxa that later achieved circumboreal distributions. A cosmopolitan spe- cies, Hiatella arctica (Linnaeus), that forms 3% of the fauna, is the most abundant element in the collections. The Narrow Cape Formation: Richly fossiliferous sandstones, siltstones, and conglom- erates which crop out along the headland of Narrow Cape on the east side of Kodiak Island have been named the Nar- row Cape Formation by Moore (1969). The formation rests with prominent angular unconformity on the Eocene and Oligocene Sitkalidak Formation. MAcNEIL (1965), Moore (1969), PLAFKER (1971), WAGNER (1974), and ALLISON & ADDICOTT (1973, 1976) have all referred these strata to the provincial middle Miocene. The megainvertebrate fauna of the Narrow Cape For- mation is poorly known, but consists of at least 80 taxa. Fossil collections have been made by the writer and Carol Wagner Allison in 1969, and by W. O. Addicott, J. Wyatt Durham, Saburo Kanno, and the writer in 1970. The Narrow Cape Formation belongs to the Newport- ian Stage (AppIcoTT, 1976; ALLISON, 1976). Mytilus mid- dendorffi Grewingk, which is restricted to the Newportian Stage (ALLISON & AppICOTT, 1976), ranges throughout the Narrow Cape Formation. The Newportian Stage is equiv- alent to the upper Saucesian to the Luisian Stages of the West Coast benthic foraminiferal chronology (ALLISON «& ADDICOTT, 1976), an interval that BERGGREN & VAN Cov- VERING (1974) refer to the late early to early middle Mio- cene. This age assignment is also confirmed by the known ranges of other molluscan taxa. The molluscan fauna of the Narrow Cape Formation suggests that deposition occurred within the neritic zone. In the lower coarser-grained portion of the formation, a number of beds are composed primarily of molluscan shells and shell detritus. These shell beds contain abundant Pseudocardium and Mytilus middendorffi, both with heavy valves, well adapted to wave surge in the inner neritic and shallow subtidal environments. These richly fossiliferous beds may be storm concentrations of shell material. Kewia kannoi Wagner is also found here, and is thought to indi- cate an inner neritic environment. The upper part of the Narrow Cape Formation is com- posed of finer-grained more massive sandstone and silt- stone, and lacks the prominent shell beds. Fossils are sporadic here; these strata appear to have been deposited in slightly deeper water than existed during deposition of the lower part of the formation. Water depth appears to have been within the outer neritic depth zone and no deeper than about 130m. Molluscan assemblages of the Narrow Cape Formation indicate warm water conditions within the warm temper- ate climatic belt of Hat (1964). Cooler water genera, whose members are not found living in water warmer than the warm temperate zone include Acila, Clinocardium, Page 174 Cyclocardia, Mya, Colus, and Cryptonatica. Warm-water genera which presently live in water no cooler than the warm temperate zone include Anadara, Chione, and Dosi- nia. The presence of the gastropod Ficus, which appears to be limited today to the inner and outer tropics, is one of the most convincing indicators of warm water condi- tions. The Narrow Cape fauna appears to represent the warmest water conditions known among the Oligocene to Recent faunas of the Gulf of Alaska region. ADDICOTT (1969) has discussed this Neogene warm water maximum and its effect on the latitudinal range of Dosiniaand Ficus. Although the full faunal composition of the Narrow Cape Formation is not yet known, both western North American and Asiatic faunal affinities are apparent. Of the go taxa analyzed here, approximately 53% have western North American affinities, about 33% have Asiatic affini- ties, and about 13% are endemic to the high latitude North Pacific perimeter. One species, Natica cf. N. clausa (Brod- erip & Sowerby), (3% of the fauna; included with the en- demics) is a precursor of the living circumboreal species. The Narrow Cape fauna is also notable in that it is dif- ferent from the contemporary fauna of the lowermost mainland Yakataga Formation in the Yakataga district. In contrast to the Narrow Cape fauna, the Yakataga fauna is a cool-water fauna showing substantial endemism and re- lationship to the modern cool-water fauna of the Gulf of Alaska. This fact has hindered detailed correlation be- tween the two faunas. Unga Conglomerate Member of the Bear Lake Formation: The name “Unga Conglomerate” was proposed by DALL & Harris (1892: 234) for brown conglomerates which over- lie coal-bearing strata on Unga Island, Alaska. BurK (1965: 92-93) referred to the Unga Conglomerate as a member of his Bear Lake Formationand designated the typesection to consist of all the strata exposed west of Zachary Bay. Thus his 244m thick measured section of the type Unga Con- glomerate Member west of Zachary Bay (Burk, 1965: 212) includes not only the coarse conglomerate of Dall and Har- ris’s Unga Conglomerate, but several hundred feet of un- derlying sandstone, conglomerate, and lignitic leaf-bearing siltstone. The base of the Unga Conglomerate was consid- ered by Burk to be the unconformity between the under- lying Stepovak Formation and the lignitic beds; unfortu- nately, this contact is not exposed at the type locality of the Unga Conglomerate. The age of the Unga Conglomerate is difficult to deter- mine because diagnostic fossils are rare, but much confu- sion also stems from mis-allocation of fossil localities and mixing of fossil collections made in the 1800's. Further THE VELIGER Vol. 21; No. 2 complications have arisen from the widely reported occur- rence of Mytilus middendorffi in the coarse clastics of the Unga Conglomerate (ALLISON & ADDICOTT, 1976); although this species is correctly considered to be a provincial middle Miocene (Newportian-Temblor) index species, the Unga Conglomerate Mytilus is in fact different, and has been described as Mytilus gratacapi Allison & Addicott. Mac- NEIL (1973) has presented the most inclusive account of Unga Conglomerate fossil mollusks. Analysis of the known stratigraphic ranges of the few taxa identified suggests that the marine beds of the Unga Conglomerate are no younger than early Wishkahan and no older than late Newportian (Figure 2). All the mollus- can taxa reported from the Unga Conglomerate, with the exception of the questionably identified Epitonium cf. E. clallamense Durham, are compatible with, or restricted to, some part of the Newportian to Wishkahan interval. Only two species, ?Sanguinolaria ochotica Slodkevich, and Epi- tonium cf. E. howei Durham, would indicate restriction to the Wishkahan Stage alone; both taxa are doubtfully iden- tified and weak bases for correlation. Three species indi- cate an age no younger than Newportian: ?Colus kurodai ’(Kanehara), of H1rAYAMA (1955) (see MACNEIL, 1973), possibly Ocenebra topangensis Arnold, and Cyclocardia cf. C. kevetscheveemensis (Slodkevich) (seems to indicate only a late Newportian age). The view that Mytilus grata- capi descended from the Newportian Mytilus midden- dorffi (ALLISON & ADDICOTT, 1976) is compatible with a late Newportian age for the Unga Conglomerate Member. Although the evidence favors the late Newportian age, an early Wishkahan age cannot be totally excluded. The leaf-bearing non-marine beds, which belong to the Seldovian Stage (WOLFE in Burk, 1965: 234) are probably not younger than Newportian but could be older (the Homerian-Seldovian Stage boundary is about 12.5 m.y.: personal communication, J. A. Wolfe, Jan., 1976). The presence of Seldovian plant fossils in the Stepovak Forma- tion at Coal Bay (WoLFE in Burk, 1965: 88, 233, 234) sug- gests that these lowermost non-marine strata may be more reasonably referred to the Stepovak Formation. The Narrow Cape Formation may be partially coeval with the Unga Conglomerate Member, or may be wholly older. The Unga Conglomerate Member appears to be of latest early to middle Miocene age. MACNEIL (1973: 117) has, however, interpreted the Unga Conglomerate fauna to be slightly older. Although many of the taxa reported here from the Unga Conglomerate Member of the Bear Lake Formation are rather wide ranging in water depth, it is clear that deposi- tion took place under conditions ranging from subaerial to water depths no greater than about go m (upper part of the outer neritic zone). Much of the unit was probably depos- Vol. 21; No. 2 THE VELIGER Page 175 ited in the inner neritic and shallow subtidal part of the inner neritic zone. Fossil wood and upright tree stumps in the Unga Conglomerate of Unga Island (Burk, 1965; EAKINS, 1970) indicate subaerial conditions. A number of small collections of mollusks from the Alaska Peninsula north of Unga Island, however, show the latter area to have been one of marine clastic deposition. The very heavy shell of Mytilus gratacapi suggests adaptation to high en- ergy nearshore environments on exposed coastlines with heavy wave surge and surf (ALLISON & ADDICOTT, 1976). The heavy shelled mactrid genus Pseudocardium also sug- gests a nearshore high-energy environment and probably indicates shallow water. The Unga Conglomerate Member was probably depos- ited in water of the warm temperate province [no cooler than 10°C surface temperature (HALL, 1964), substan- tially warmer than that of the present Gulf of Alaska]. The available small molluscan collections suggest that water temperatures were similar during deposition of the Unga Conglomerate Member and during the deposition of the remainder of the overlying Bear Lake Formation. The very poorly known molluscan fauna of the Unga Conglomerate Member appears to contain faunal elements with both western North American and Asiatic affinities. Of the 17 taxa analyzed here, six (35%) seem to be of Asian affinities, and 4 (24%) seem related to western North American stocks. The remaining 7 taxa (41%) are either locally endemic, or endemic to the higher latitude perim- iter of the North Pacific. Bear Lake Formation, unnamed upper member: The type locality of the Bear Lake Formation is in the mountains above and eastward from Bear Lake, just east of Port Moller. These marine clastic sedimentary rocks have been mapped by Burk (1965) on the Alaska Penin- sula between Cold Bay on the west and Black Peak near Chignik Bay on the east. Bear Lake Formation beds above the Unga Conglomerate Member have not been given a member name. The overlying yellow, brown, or gray lithic subgraywackes, lithic arenites, and shales differ sharply from the volcanic detritus of the basal conglomerate. The Bear Lake Formation is at least 1525 m thick in the vicinity of Port Moller, and may be twice this thick (BuRK, 1965). It is unconformably overlain by volcanic breccias, or by marine sandstone and conglomerate which I refer to the Tachilni Formation. In the Black Peak area, beds mapped as Bear Lake Formation by Burk (1965) are now known to contain a major angular unconformity. This feature separates an overlying cool-water molluscan fauna, which I consider correlative of the Tachilni Formation, from an underlying warmer-water molluscan fauna typical of the Bear Lake Formation proper. The Bear Lake Formation is richly fossiliferous locally. The upper part of the formation contains oysters, clams, and sand dollars which may form shell banks in which fos- sils constitute as much as a third of the rock volume (Burk, 1965). Nevertheless only meager collections are presently available for study. A megainvertebrate fauna of about 40 species is known from the Bear Lake Formation above the Unga Conglomerate and below the uncomformably over- lying strata. There is little doubt that careful collection of the Bear Lake Formation could materially enlarge the faunal list. MAcNEIL (17 Burk, 1965) and ALLIsoN & ADDICOTT (1976) have considered the type Bear Lake Formation to be of provincial late Miocene age. My analysis of the mol- luscan fauna of the upper unnamed member of the Bear Lake Formation below the unconformity shows it to be- long to the Wishkahan Stage of Appicotr (1976). The Wishkahan Stage is late middle to late Miocene in the sense of BERGGREN & VAN COUVERING (1974). Species which oc- cur in the Bear Lake Formation that are not known in strata older than those of the Wishkahan Stage include Acila cf. A. empirensis Howe, Chione cf. C. securis (Shu- mard), Clinocardium hannibali Keen, Clinocardium sp. aff. C. nuttall: (Conrad), Clinocardium cf. C. pristinum Keen, Siliqua sp. (generic range in Pacific Northwest only), and Tellina aragonia Dall. In addition, Clinocardium han- nibali Keen, Clinocardium pristinum Keen, and Tellina aragonia Dall are not known from strata younger than those of the Wishkahan Stage. The molluscan assemblages from the Bear Lake forma- tion are clearly indicative of deposition in the neritic zone; many of the collections are indicative of the inner neritic zone. Some assemblages bearing Mytilus gratacapi and Macrocallista n. sp. suggest very shallow subtidal depo- sition. Bear Lake faunal assemblages whose stratigraphic posi- tion is not in doubt give clear indications of water tem- peratures warmer than at present in the Gulf of Alaska. Although the majority of genera found in the unit still occur at the latitude of the Alaska Peninsula, at least 6 are extralimital thermophiles. These genera are: Anadara, Macrocallista, Musashia, Chione, Septifer, and large Tur- ritella. Chione and Anadara suggest water no cooler than warm temperate [no cooler than 10°C surface temper- ature (HALL, 1964)]. Musashia and Septifer suggest water no cooler than mild temperate, and large Turritella are found no farther north than at the southern limit of the North Pacific cool temperate water mass off Asia. Macro- callista is restricted to tropical waters today, but almost Page 176 certainly inhabited cooler water in the western and eastern North Pacific in the past. No frigophilic extralimital gen- era are known from the Bear Lake Formation. The molluscan fauna of the Bear Lake Formation is a mixture of both Asiatic and western North American faunal elements. Approximately 21% of the 29 taxa se- lected for faunal analysis appear to have Asiatic faunal affinities, and 48% seem related to western North Amer- ican stocks. Thirty-one percent of the fauna is endemic to the high latitude perimeter of the North Pacific. About 10% of the taxa (included with the endemics) is composed of precursors of species that later achieved circumboreal distributions. Tachilni Formation: WALDRON (1961) applied the name “Tachilni Forma- tion” to fossiliferous sandstone, conglomerate, and black shale that crop out along the Pacific coast of the Alaska Peninsula between Thinpoint Cove and Cape Tachilni, near the entrance to Morzhovoi Bay. The Tachilni For- mation contains much volcanogenic material in which fossil mollusks occur. To the east, the formation is uncon- formably overlain by the Morzhovoi Volcanics, but to the west the contact between the two units is gradational. On a regional basis, the Tachilni unconformably overlies the Bear Lake Formation. The thickness is unknown, but at the Cape Tachilni type locality, more than 61 m of richly fossiliferous, poorly consolidated sandstone crops out. Fos- siliferous marine sedimentary rocks in the Black Peak- Milky River area of the Alaska Peninsula unconformably overlie the fossiliferous late middle to late Miocene Bear Lake Formation. In the writer’s view, these strata are coeval with the Tachilni Formation, although Burk (1965) mapped them as part of his Bear Lake unit. The megainvertebrate fauna of the Tachilni Formation is poorly known. MACNEIL (1970) described two new mol- lusks, and WAGNER (1974) described three new echinoids from these beds. I have recognized 19 taxa in Tachilni Formation fossil collections, although the fauna is doubt- less larger. Seven species are only known from the Alaska Peninsula. Among the remaining taxa, known occurrences suggest that the Tachilni Formation is no older than the Jacalitos Formation and no younger than the Etchegoin Formation, both of California. Polinices galianoi Dall is not known in beds younger than the Etchegoin Formation of the San Joaquin Basin and the basal Merced Formation of central California. Crenomytilus coalingensis (Arnold) is known from beds as old as the Jacalitos and Castaic For- mations of California and as young as the San Joaquin Clay of the Kettleman Hills, California. Mya elegans (Eichwald) THE VELIGER Vol. 21; No. 2 suggests that the Tachilni Formation is no older than the Jacalitos Formation of California because MAcNEIL (1965, p. G-23, G-go) has interpreted it to be a descendant of the provincial late Miocene Neroly Formation species, Mya dickersoni Clark. Remondella waldroni Wagner occurs with Echinarachnius cf. E. ungaensis Wagner and seems to be closely related to the only other known species of Remondella, R. gabbi (Remond) from the provincial late Miocene of California (Cierbo through uppermost Neroly Formations of Mt. Diablo area). WAGNER (1974) notes that R. waldroni is more highly evolved, and therefore presum- ably younger, than R. gabbi. Although MacNet et al. (1961), MACNEIL (1970), and WAGNER (1974), have referred the Tachilni Formation to the provincial early Pliocene, the formation is here re- garded as late Miocene. The Jacalitos to Etchegoin inter- val is probably best referred to the upper Mohnian to lower Delmontian benthic foraminifer Stages, approxi- mately correlated with the Graysian molluscan Stage of the Pacific Northwest (AppicoTT, 1976: 98). Because the lower part of the San Joaquin Formation, which overlies the Etchegoin Formation of California, has been radiometri- cally dated at 4.3 m.y. (REPENNING, 1976: 310), it is prob- able that the Etchegoin Formation is best referred to the latest Miocene. AppicotT (1976: 96 and 110) also provi- sionally places the Graysian Stage in the latest Miocene. For these reasons, the Tachilni Formation is here regarded as the latest Miocene, although the Miocene-Pliocene boundary may fall within it. The Tachilni fauna appears to represent the shallow subtidal part of the inner neritic environment. Taxa whose modern analogs are restricted to shallow water include: Kewia, Spisula, Crenomytilus, Macoma cf. M. nasuta (Con- rad), Szliqua, Protothaca, and Mya elegans (Eichwald). In particular, Mya elegans is restricted to the shallow subtidal part of the inner neritic zone. The mollusks of the Tachilni Formation indicate cool temperate water conditions similar to the present Gulf of Alaska. Many genera are wide ranging thermally, but Beringius, Spisula voyi (Gabb) and Mya elegans are north- ern cool-water taxa. CHAMBERLAIN & STEARNS (1963) con- sidered Spisula voy to be conspecific with S. polynyma (Stimpson) and report that this pelecypod is thermally lim- ited by water warmer than about 13° C mean annual tem- perature. No uniquely warm-water taxa are known from the Tachilni Formation. The small sample of the Tachilni molluscan fauna sug- gests that about 21% of the species are related to taxa from the west coast of North America, and that about 63% are endemic to the higher latitude perimeter of the North Pa- cific. About 16% of the taxa are related to Asian species, Vol. 21; No. 2 THE VELIGER Page 177 and about 26% of the fauna (included with endemics) have affinities with North Atlantic stocks which probably descended from Pacific progenitors, possibly the Tachilni taxa themselves. Tugidak Formation: The Tugidak Formation is a 1 500 meter-thick sequence of interbedded sandstone, siltstone, and conglomeratic sandy mudstone which crops out along the coastal bluffs and intertidal reefs of Tugidak and Chirikof islands, Alaska (Moore, 1969). These strata contain randomly dis- tributed pebbles and cobbles of glacial-marine origin. The base of the formation is not exposed. Unnamed marine Pleistocene beds conformably overlie the Tugidak Forma- tion on Chirikof Island (Moore, 1969). MAcNEIL (in Moore, 1969), AppicoTT (in Moore, 1969) and PLAFKER (1971) have all considered the Tugidak Formation to be Pliocene. About go fossil collections have been examined by the writer. They show the fauna to be diverse (more than 80 species) and largely composed of living, cold-water, North Pacific and Arctic taxa. No satisfactory biostratigraphic standard yet exists for western North American late Neogene offshore molluscan faunas, which makes interpretation of the precise age and correlation of the Tugidak fauna difficult. Accordingly, the age of the Tugidak fauna is best determined with refer- ence to the late Pliocene and Pleistocene transgressions of Beringia (Hopkins, 1967, 1973; Hopkins e¢ al., 1974). No paleomagnetic geochronologic data are presently available for the Tugidak Formation. The few extinct species in the Tugidak fauna indicate the best comparison to be with faunas of the late Pliocene Beringian and early Pleistocene Anvilian transgressions. The following Tugidak taxa have their first known ap- pearance in strata of Beringian age: Astarte elliptica (Brown), Astarte hemicymata Dall, Astarte montagui (Dillwyn), Astarte cf. A. nortonensis MacNeil, Astarte rol- landi Bernardi, Buccinum cf. B. glaciale Linnaeus, Colus cf. C. spitsbergensis (Reeve), Epitonium greenlandicum (Perry), Epitonium greenlandicum smithi MacNeil, Plici- fusus cf. P. brunneus (Dall), Polinices pallidus (Broderip & SOWERBY), Tachyrhynchus erosus (Couthouy), and Volu- topsius aff. V. stefanssoni Dall. Although there is good evidence that the Tugidak fauna is no older than the Beringian transgression of late Plio- cene age, the upper age limit is more difficult to establish. The presence of the very distinctive Astarte hemicymata in the Tugidak fauna is clear evidence of a Beringian to Anvilian late Pliocene to early Pleistocene age. Astarte cf. A. nortonensis indicates a Beringian to Einahnuhtan age. Comparison of the molluscan fauna to the Bering Sea trans- gressions standard does not, however, permit recognition of the Beringian or Anvilian intervals by themselves. Therefore, it is not clear whether the Tugidak Formation is totally of late Pliocene age, totally of early Pleistocene age, or whether it contains the Pliocene-Pleistocene bound- ary. Fossil pectinids suggest that the upper part of the Tugidak Formation correlates with the lower part of the Yakataga Formation on Middleton Island (MacNEIL & PLAFKER in Moore, 1969) and the Middleton Island sec- tion is of demonstrable Pleistocene age (PLAFKER & ADpI- cotr, 1976; Plafker, oral communication, November, 1975). Available data therefore suggest that the Tugidak Formation is of late Pliocene and Pleistocene age. Analysis of depth ranges of taxa from 20 fossil localities representing 18 different stratigraphic levels in the Tugi- dak Formation suggests that deposition took place in the upper part of the outer neritic zone. Eleven assemblages indicate maximum depths no greater than 145 m, and one suggests water no deeper than 111 m. Three assemblages suggest water depths no shallower than about 119m and 5, others indicate water no shallower than about 37 m. All the assemblages studied are compatible with neritic water depths between 91 and 145 m. Tugidak Mollusca clearly represent cold-water condi- tions, colder than the present Gulf of Alaska. It seems likely that the Bering Strait was open and that there were marine connections through the Arctic to the Atlantic. Species of Atlantic origin (DURHAM & MaAcNEIL, 1967) include Astarte elliptica (Brown), Astarte montagui (Dill- wyn) [=<. fabula Reeve], Hiatella arctica (may have reached the Pacific in the tropics rather than through the Arctic, however), and Moelleria costulata (MGller). Ock- ELMANN (1954) has suggested that Yoldia myalis (Cou- thouy) also originated in the Atlantic Ocean. Several cir- cumboreal species in the Tugidak Formation suggest that the water temperature was cooler than that at Tugidak to- day. These species, which do not now range as far south as Tugidak Island, include Axinopstda cf. A. orbiculata (Sars), Nuculana pernula (Moller), Yoldia hyperborea? Torrell, Boreotrophon ciathratus (Linnaeus), Boreotro- phon truncatus (Strom), Buccinum cf. B. angulosum nor- male Dall, Moelleria costulata and Velutina undata? Brown. Extralimital warm-water taxa are not known from the Tugidak Formation. The Tugidak fauna is of North Pacific origin with ap- proximately 83% of the fauna endemic to the high latitude perimeter of the North Pacific Ocean and the Bering Sea. Forty-six percent of the fauna (included with the endemics) have circumboreal distributions, and about 10% of the fauna seems to have western North American affinities. Page 178 THE VELIGER Vol. 21; No. 2 Only about 5% of the taxa (some pectinids) suggest pri- mary Asiatic relationships, and one species (1% of those analyzed) is cosmopolitan. NORTHEASTERN GULF or ALASKA STRATIGRAPHIC UNITS The Poul Creek Formation: The Poul Creek Formation was named by TALIAFERRO (1932) from exposures of marine sedimentary rocks which crop out along Poul Creek in the Robinson Mountains of the Yakataga District, Alaska. The formation is composed of reddish-brown-weathering massive concretionary silt- stone, sandy mudstone, and fine- to medium-grained sand- stone. Glauconitic sandstone is locally abundant. The upper part contains a massive non-resistant siltstone which forms a prominent topographic swale along the front of the Robinson Mountains eastward from Yakataga Reef and a prominent covered interval at the reef itself. The 1859 meter-thick formation (MILLER, 1957) is thought to over- lie the Paleogene Kulthieth Formation conformably, and is conformably overlain by the Yakataga Formation in the vicinity of Cape Yakataga. The most continuous section is exposed in a south-facing cliff at the head of Yakataga Gla- cier in the Robinson Mountains. MILLER (1961: 242) notes that the contact with the overlying Yakataga Formation is gradational through a 15 to 61 meter interval in most places in the Yakataga District. The contact between the Poul Creek and overlying Yakataga Formation has been variously placed by different authors. Field examination of the contact in several sec- tions of the Robinson Mountains by C. Ariey and the writer confirms MILLER’s (1961) view that the contact is gradational. In the gradational interval, glauconitic sand- stone and rusty-weathering siltstone of typical Poul Creek lithology alternate with typical Yakataga Formation lithol- ogy of gray-weathering sandstone containing scattered peb- bles. This gradational interval generally coincides with a change in the molluscan fauna. The formational contact is best defined within the gradational interval at the most prominent break between pebble-bearing sandstones above, and rusty-weathering glauconitic siltstones or sand- stones below (C. Ariey, pers. commun., 1974). Use of these criteria at Yakataga Reef places the boundary above KANNO’s (1971) contact, and below KANNo’s (1971) inter- pretation of MILLER’s (1957) boundary; it is therefore here considered to be at a point about 41 meters above the prominent covered interval (C. Ariey, personal communi- cation, 1974). PLAFKER & ADDICOTT (1976: 5) advocate similar criteria for the formational boundary. The Poul Creek contains a fairly large molluscan fauna. Using the upper formational boundary advocated here, I have compiled a faunal list of 87 megainvertebrate taxa from University of Alaska collections and published re- ports [CLARK (1932), DURHAM (1937), PARKER (1949), MILLER (1961), MAcNezIL (1961, 1965, 1967), ADEGOKE (1967), MACNEIL in MILLER (1971), KANNO (1971), ADDrI- corr et al. (1971), KANNo (1973), and Appicorr (1976)]. Analysis of the molluscan assemblages and species ranges shows that the uppermost strata belong to the Pillarian Stage (ApDICOTT, 1976: 101-102). Species not known to range into strata younger than the Pillarian Stage include: Acila gettysburgensis (Reagan), Pitar arnoldi (Weaver), Solemya dalli Clark, Vertipecten fucanus (Dall), Ancistro- lepsis rearensis (Clark), Epitonium clallamense Durham, and Priscofusus stewarti (Tegland). Anadara aff. A. os- monti (Dall) and Vertipecten fucanus (Dall), which occur in the upper Poul Creek, are not known to occur in beds older than the Pillarian Stage. The oldest dated beds of the Poul Creek belong to the Echinophoria dalli Zone (ARMENTROUT, 1975), but a re- " fined age for the Kulthieth-Poul Creek boundary is not yet available. It should be noted that many molluscan taxa reported by KANNO (1971) are from stratigraphically lower beds exposed in the Sullivan Anticline, but these beds are not in the lowermost part of the formation which crops out at the head of Yakataga Glacier, in the Grindle Hills, and along the Kosakuts River (KANNO, 1971: 14). The follow- ing species, from the lowermost Poul Creek Formation, are not known to range into strata older than those of the Echi- nophoria dalli Zone: Cyclocardia aff. C. hannibali (Clark), Panopea snohomishensis Clark, Pitar aff. P. dalli (Weaver), Solena aff. S. eugenensis (Clark), Thracia cf. T. condoni Dall, Molopophorus stephensoni Dickerson, Perse olympi- censis Durham, and Perse olympicensis quimperensis Dur- ham. Species which occur in the lowermost Poul Creek Formation and are not known in beds younger than the Echinophoria dalli Zone include Nemocardium weaveri (Anderson & Martin), Solen townsendensis Clark, Molopo- phorus stephensoni Dickerson, Perse olympicensis Dur- ham, and Perse olympicensis quimperensis Durham. MILLER’s (1961: 243-245) report of Patinopecten (Litu- yapecten) from the uppermost part of the Poul Creek For- mation can be disregarded because these strata are now included in the basal part of the overlying Yakataga For- mation. ADDICOTT (1972: 12) notes that Patinopecten has its earliest occurrence in the ‘““Temblor Stage’ (—New- portian Stage) of California. The appearance of Patino- pecten (Lituyapecten) in the basal beds of the Yakataga Formation is taken here to mark the beginning of New- portian time. Vol. 21; No. 2 Following BERGGREN & VAN CouveERING’s (1974) chro- nology, the Poul Creek Formation ranges in age from the late Eocene (upper Refugian benthic foraminifer Stage) to the early Miocene (lower Saucesian benthic foraminifer Stage). Evaluation of Poul Creek molluscan assemblages indi- cates that deposition took place in the lower inner neritic and outer neritic depth zones. Among 10 assemblages which contain genera suggestive of minimal water depth, 2 indicate water no shallower than about 21 meters, 6 no shallower than 37 meters, and 2 no shallower than 50 meters. Four assemblages indicate water depths no greater than about 111 meters, 3 no deeper than 143 meters, 1 no deeper than 165, meters, and 3 no deeper than 186 meters. Rau (1963) infers water depths between 61 and 244 meters (outer neritic to uppermost bathyal) from a benthic fora- miniferal assemblage near the top of the formation. The Poul Creek fauna is indicative of warm-water sim- ilar to the present North Pacific warm temperate belt (HALL, 1964). The oldest fossil assemblages include the genera Nemocardium, Solen, Turritella, ?Cylichna, ?Exi- lia, ?Parvicardium, ?Pitar and ?Spisula, as well as the ex- tinct gastropods Molopophorus and Perse; these taxa appear to indicate a warm temperate marine climate. Several genera in the middle to upper parts of the for- mation indicate temperatures no cooler than the warm temperate zone; these are: Crassatella, Macrocallista, Pa- pyridea, and Eosiphonalia. Genera which suggest tempera- tures no warmer than the warm temperate zone include Clinocardium, Cyclocardia, Mya, Nemocardium, Ancis- trolepsis, Bathybembix, Colus, Natica (Cryptonatica), and Pteropurpura. The youngest (Pillarian) Poul Creek strata also contain very large specimens of Panomya arctica (La- marck) (C. Ariey, personal communication, 1975), a spe- cies which does not range into water warmer than that of the mild temperate zone today. Some evidence suggests the beginning of cooling conditions during latest Poul Creek time; the bulk of the data, however, indicate the Poul Creek molluscan faunas to be of warm temperate character. The Poul Creek fauna is most closely related to that of the Tertiary of the Pacific northwest coast of North Amer- ica. Approximately 52% of the Poul Creek species have western North American affinities and about 18% of the fauna is related to that of Asia. Approximately 30% of the Poul Creek fauna was locally endemic, or was distributed around the high latitude North Pacific perimeter. Six per- cent of the fauna (included with the endemics) is composed of precursors of taxa that later achieved circumboreal dis- tributions. Although these numbers differ somewhat from those of KANNO (1971: 17), they suggest the same relative THE VELIGER Page 179 weighting between North American, Asian, and endemic faunal elements. The Yakataga Formation: The Yakataga Formation was named by TALIAFERRO (1932) for “‘a thick series of sandstones, dark shales, and conglomerates” which overlies the Poul Creek Formation at Yakataga Reef and in the Sullivan Anticline area of the Robinson Mountains. PLAFKER & AppICcoTT (1976: 6) have designated the type section as an 1 800 meter-thick se- quence of beds between the contact of the Poul Creek For- mation at the head of Poul Creek and the southern margin of Guyot Glacier north of Munday Peak. The Yakataga Formation extends over a broad area of the northeastern Gulf of Alaska, from the Suckling Hills of the Katalla dis- trict on the west to Icy Point in the Lituya district on the east. It also crops out on Kayak, Middleton, and Wingham islands, and probably occurs over much of the adjacent continental shelf of the Gulf of Alaska (op. cit., p. 4). It has acomposite thickness of about 5 000m (op. cit.) of which the upper 1181 m are exposed on Middleton Island (PLAFKER, 1971). A major intraformational unconformity occurs within 1500 m of the base of the formation in the Yakataga- Malaspina districts (ADpICOTT & PLAFKER, 1976: 15). Till- like glaciomarine diamictite or “conglomeratic sandy mudstone”’ occurs in all but the basal part, and is abundant in much of the formation (op. cit., p. 9). Glaciomarine dropstones occur in all lithologies and are primary compo- nents of the diamictites. Glacial striae are observed on scattered clasts (op. cit., p. gb-10). Although the youngest outcrops are on Middleton Island, marine seismic profiling and bottom sampling indi- cate that the youngest part of the formation includes un- lithified Holocene deposits (PLAFKER & ADDICOTT, 1976: 6). The oldest strata assigned to the Yakataga Formation occur on Kayak Island (PLAFKER, 1974; PLAFKER & ADDI- COTT, 1976) and are older than the basal Yakataga Forma- tion beds at Yakataga Reef and in the Sullivan Anticline area. This section of the paper deals primarily with the pre- Pleistocene faunas of the Yakataga Formation of the Ka- talla, Yakataga, Malaspina, Yakutat, and Lituya districts. The Pleistocene portion of the Yakataga Formation at Middleton Island is treated separately. The oldest strata recognized in the formation occur on Kayak and Wingham islands. Although a number of mol- luscan taxa are reported from Kayak and Wingham islands by Appicott in PLAFKER (1974), only two stratigraphically significant species, Acila gettysburgensis (Reagan) and So- Page 180 THE VELIGER Vol. 21; No. 2 lemya dalli Clark, occur in these strata. The co-occurrence of these taxa in the “lower part of the Yakataga Formation” (PLAFKER, 1974), south of the Kayak Fault on eastern Kayak Island, indicates a Juanian to Pillarian age, that is, latest Oligocene to early Miocene in the sense of BERGGREN & VAN COUVERING (1974). PLAFKER (1974) reports a sparse foraminiferal assemblage of possible Zemorrian, and there- fore probable, Juanian age. Slightly younger strata on Kayak Island, referred to the “upper part of the Yakataga Formation” (PLAFKER, 1974) also contains Acila gettysburgensis. The co-occurrence of this species, which is not known to range into strata younger than Pillarian age (AppICOTT, 1976b) with fora- miniferal assemblages of Saucesian or Relizian age (PLAF- KER, 1974) suggests that these strata belong to the Pillarian Stage of the early Miocene. Recognition of Juanian (?) and Pillarian strata in the lower Yakataga Formation indicates that the upper Poul Creek Formation of the Yakataga area and the lower Yakataga Formation of Kayak Island are coeval. Strata near the base of the Yakataga Formation at Yaka- taga Reef are here considered to belong to the late early to early middle Miocene Newportian Stage. The Newportian age is based on the presence of Macoma arctata (Conrad) (KANNO, 1971, loc. 80605), which is not known to occur in strata younger than those of Newportian age, and the genus Patinopecten which is not known to occur in strata older than those of the Newportian Stage (ADDICOTT, 1974: 183; 1976: 98). The lowest known stratigraphic occurrence of Patinopecten at the reef seems to be that of KANNO (1971: 53, and USGS loc. M271, probably equal to Kanno’s loc. 80903). This locality is approximately 10 meters above the Poul Creek-Yakataga contact, as used here (see discus- sion under Poul Creek Formation) or about 51 m strati- graphically above the prominent covered shale of the upper Poul Creek Formation at the reef (measured section of C. Ariey, personal communication, August, 1976). PLAFKER & ADDICOTT (1976) also list Molopophorus mat- thewi Etherington from the lower Yakataga Formation in the Yakataga district; although the exact stratigraphic po- sition is not reported, this species is considered to be re- stricted to the Newportian Stage. Unpublished research by C. Ariey (personal communi- cation, June, 1977) suggests that the Newportian-Wish- kahan boundary is located approximately 30 m above the base of the Yakataga Formation, and that Newportian strata therefore constitute a very thin stratigraphic inter- val in the Yakataga District. This conclusion is based upon the first appearance of Siliqua and Yoldia (Cnesterium) which are thought to be indicative of strata no older than the Wishkahan Stage in the northeastern Pacific. Other modern taxa which first appear in this stratigraphic posi- tion include Mya truncata Linnaeus, Solamen cf. S. colum- bianum (Dall), Miyagipecten sp., Yabepecten sp., Laqueus californianus (Koch), and Bittium cf. B. frankeli Faustman (personal communications, C. Ariey and S. McCoy, Jan., 1978). Deposits of Wishkahan, Graysian, Moclipsian, and younger are clearly present in the Yakataga Formation, but the boundaries between these stages, as well as those of the European series-epochs, are presently extremely dif- ficult to place. This stems from lack of published faunal lists for specific fossil localities of known stratigraphic posi- tion in the part of the formation stratigraphically above Yakataga Reef, as well as from the increase of endemic and living species in these younger strata. PLAFKER & ADDICOTT (1976: 22) observe that correlation is also hindered by the tendency of late Cenozoic cold-water mollusks to be un- usually long-ranging. WAGNER (1974) notes the presence of Scutellaster ore- gonensis (Clark) in the Yakataga Formation of the La Perouse Glacier and Topsy Creek areas of the Lituya Dis- trict. This species is restricted to strata of Wishkahan age in the Pacific Northwest. MAsuDA & ADDICOTT (1970) ques- tionably report Yabepecten condoni (Hertlein) [—=? Miya- gipecten alaskensts MacNeil] from a nunatak north of the east end of the Pinnacle Hills in the Malaspina district; this species appears to be restricted to deposits of Graysian age (ADDICOTT, 1976). MAcNEIL (1961) reported Patino- pecten (Lituyapecten) cf. P. (L.) dillert (Dall) from the coast south of Lituya Bay; P. (L.) dilleri s. s. is restricted to deposits of Moclipsian age (AppIcoTT, 1976). Although the geographic occurrence is unknown, the appearance of a species of Atlantic origin, Astarte aff. A. elliptica (Brown) [= A. alaskensis Dall}, about 2438 m above the base of the Yakataga (MacNEIL in MILLER, 1971; MacNEIL, 1965: 6-8) is indicative of a Beringian or younger age. Many other molluscan taxa indicative of Beringian and younger ages occur in the upper Yakataga Formation of the main- land. Chlamys chaixensis MacNeil and Chlamys lioica (Dall) co-occur in the highest Yakataga strata in the Chaix Hills of the Malaspina District; these beds are no older than the Beringian transgression, and are probably An- vilian (early Pleistocene) in age (PLAFKER & ADDICOTT, 1976). These strata may be younger than the Chlamys (Leochlamys) tugidakensis range zone of Tugidak and Middleton Islands. In summary, the oldest strata of the Yakataga Formation occur on Kayak Island; they are at least as old as the Pil- larian Stage, and could be as old as the Juanian Stage. The youngest Yakataga strata in the Yakataga to Lituya dis- tricts are probably coeval with the Middleton Island An- vilian beds and could be in part younger than the Chlamys (Leochlamys) tugidakensis Range Zone. The Yakataga Vol. 21; No. 2 Formation therefore appears to range from late Oligocene (?) or early Miocene (Juanian? to Pillarian) to early Pleisto- cene (Anvilian). The oldest Yakataga strata, at Kayak and Wingham islands, were deposited in upper bathyal water depths. The lower Yakataga of the Yakataga District seems to have been deposited in lower inner neritic to outer neritic water depths. Younger parts of the formation in the Malaspina to Lituya districts to the southeast may be inner neritic. The youngest beds of the formation at Kulthieth Moun- tain and Pinnacle Pass appear to be intertidal to shallow sublittoral deposits. It therefore appears that water depth became generally shallower upsection. Although not as well documented, there also seems to be a trend from deeper water offshore to shallower water onshore in the north and easterly directions. Yakataga molluscan faunas clearly indicate cooler water than that of the underlying Poul Creek Formation. Mol- lusks from the lowermost part of the Yakataga Formation on Kayak Island (Juanian? Stage) appear to indicate mild temperate conditions, probably slightly cooler than those during deposition of contemporary strata of the Yakataga District. This apparent discrepancy probably reflects the deeper, and therefore cooler, environment of deposition at Kayak Island. The “upper part of the Yakataga Forma- tion” (PLAFKER, 1974) at Kayak Island (Pillarian Stage) and Pillarian strata of the Poul Creek Formation in the Yakataga District also seem to have been deposited in mild temperate water. Yakataga molluscan assemblages re- ported by KANNo (1971) from Yakataga Reef (Newportian and probably Wishkahan) suggest slightly cooler tempera- tures, probably like those near the mild temperate-cool temperate boundary. A number of small collections from the lower Yakataga of the Sullivan Anticline and Yakataga District (KANNO, 1971) also suggest mild temperate to cool temperate conditions. Stratigraphically higher beds in the Karr Hills and the Samovar Hills (KANNO, 1971) probably were deposited in cool temperate water; these strata appear to be no older than Graysian (late Miocene). Strata which appear to be no older than the late Pliocene Beringian transgression also contain molluscan assemblages indicative of water no warmer than the cool temperate climatic zone. Yakataga molluscan assemblages therefore demonstrate that climatic deterioration continued during Miocene and Pliocene time. By early Pleistocene (Anvilian) time, the molluscan data indicate the presence of cold-water condi- tions (see section on Middleton Island Yakataga Forma- tion). All workers who have considered the paleoclimatology (e.g. BaNpy ef al., 1969; KANNO, 1971; PLAFKER & ADDI- THE VELIGER Page 181 COTT, 1976) agree that there was a temperature drop during late Poul Creek to earliest Yakataga time. My inter- pretation of the Yakataga molluscan and planktonic fora- minifer data is, however, in disagreement with the views of earlier workers in that I believe mild temperate and cool temperate rather than cold (Arctic) conditions existed throughout much of Yakataga time. KANNO (1971:24) suggests that the entire Yakataga Forma- tion was deposited in ‘Arctic’ water temperatures com- parable to those north of the present southern limit of winter sea ice. PLAFKER & ADDICOTT (1976) refer to a sharp decline in temperature across the formational contact from “temperate”’ to “cold” conditions, but do not specify how cold the Yakataga may have been. Banpy e¢ al. (1969) offer an interpretation similar to KANNO (1971) in suggesting a 10° to 15°C temperature drop across the formational boundary. This interpreta- tion is based on an influx of left-coiling Turborotalia pachyderma (Ehrenberg) near the base of the Yakataga Formation in the Yakataga District. BANpy et al. (1969) indicate that this planktonic foraminifer is similar to those now restricted to polar waters with summer surface tem- peratures of about 2° C. HERMAN (in ALLISON, 1973) points out, however, that the range of sinistral T. pachyderma is between —1° C and 5° C, but that it is occasionally found in waters up to 15° C. Banpy (1968b) notes the common occurrence of predom- inantly sinistral T. pachyderma in waters with 2° to 8° C summer temperatures, and Banpy (1968a) also points out that the southern boundary of the common sinistral T. pachyderma fauna appears to be about 45,° north latitude in the eastern Pacific off Oregon, and perhaps near 50° north latitude in the central and western Pacific. These latitudes embrace the cold or Arctic zone, the cool temper- ate zone, and parts of the mild temperate belt. On the basisof my study of the Molluscaand data (BANDy, 1968a, 1968b; HERMAN tn ALLISON, 1973) on Turborotalia pach- yderma it does not appear to me that the cold water (Arctic) paleotemperature interpretations for the bulk of the Yaka- taga Formation are defensible. Both the molluscan and planktonic foraminifer data are compatible with mild tem- perate to cool temperate conditions suggested here for the pre-Beringian portions of the formation. The Beringian and Anvilian parts of the formation, however, do appear to have been deposited in cold (Arctic) waters. Although the Yakataga molluscan fauna is incompletely known, some general paleozoogeographic trends are indi- cated. About 41% of the taxa of the lower Yakataga For- mation at Kayak and Wingham Islands is composed of species with Asiatic affinities. Asiatic paleozoogeographic affinities are less apparent in the younger (Newportian and Page 182 Wishkahan?) beds at Yakataga Reef (about 12%) and in strata younger than those of Yakataga Reef (Graysian? and younger) (about 10%). Faunal affinities with the west coast of North America increase slightly from about 14% at Kayak and Wingham islands to about 28% at Yakataga Reef and about 26% for younger strata. The fauna of the Yakataga Formation is marked by the large number of taxa which are endemic to the high lati- tude perimeter of the North Pacific or to the local outcrop area. Endemic species constitute about 45% of the fauna at Kayak and Wingham islands and increase to about 58% at Yakataga Reef. Strata younger than those of Yakataga Reef contain faunas with about 62% endemic taxa. Of interest is the number of precursors to present cir- cumboreal taxa in the Yakataga Formation. In fact, the Kayak and Wingham islands Yakataga faunas include two taxa (about 9% of the fauna; included with the endemics) that probably are ancestral to modern circumboreal spe- cies. Five of the endemic taxa (12% of the fauna) from Yakataga Reef also appear to be precursors of present cir- cumboreal taxa. About 26% (included with the endemics) of the Yakataga fauna from strata younger than those at Yakataga Reef show circumboreal paleozoogeographic af- finities. One cosmopolitan species, Hiatella arctica, (2% of the fauna) occurs at Yakataga Reef, and another, Mytilus edu- lis, (3% of the fauna) occurs in Yakataga strata younger than those of Yakataga Reef. The large endemic component of the faunas (62% of the fauna in strata younger than those at Yakataga Reef) cre- ates a major problem in correlation of these strata with coeval deposits of the west coast of the conterminous United States. Yakataga Formation on Middleton Island: Late Cenozoic glaciomarine strata crop out in the coastal bluffs and on the intertidal platforms of Middleton Island, which is located in the north-central Gulf of Alaska. PLAF- KER (1971) assigned these strata to the uppermost Yakataga Formation and reports their thickness to be 1181 m. Ma- rine fossils are sparsely distributed throughout the forma- tion in conglomeratic sandy mudstone, fine-grained sand- stone and in siltstone. Although a number of investigators have variously re- garded the Middleton Island Yakataga beds as Pliocene or Pleistocene (MILLER, 1953; MACNEIL, et al., 1961; Hop- KINS, 1967; MACNEIL, 1967; ADDICOTT, 1971), there is no convincing biostratigraphic means of recognizing the Pliocene-Pleistocene boundary in the Gulf of Alaska re- gion. PLAFKER & AppicoTT (1976) and Plafker (personal communication, Nov., 1975) report that recent geomag- netic stratigraphy studies show the Middleton Island Yaka- THE VELIGER Vol. 21; No. 2 taga Formation to belong to the Matuyama reversed polar- ity epoch (no younger than 0.7 million years b.p.). The very lowest strata exposed at Middleton Island possess nor- mal geomagnetic polarity, possibly indicating the Olduvai event of earliest Pleistocene time (—1.6 to 1.8 m.y.; BERG- GREN & VAN COUVERING, 1974: 140). The Middleton Island section is therefore here considered to be of Anvilian (early Pleistocene) age with the Pliocene-Pleistocene boundary near, but below, its base. About 65 fossil collections from the Middleton Island Yakataga Formation have been examined. Many of these are small, but they range throughout the stratigraphic sec- tion. These collections show the fauna to be somewhat less diverse (in excess of 70 species) than that of the Tugidak Formation, and on the whole not as well preserved. The molluscan fauna is largely composed of living cold-water North Pacific and boreal species, and contains about 35 taxa in common with the Tugidak Formation. This differ- ence in faunal composition probably owes in part to differ- ence in geological age as suggested by the distinct Chlamys and Astarte species; a more fundamental cause, however, _ probably is the somewhat different ecologic setting at Mid- dleton. The fossil Mollusca clearly indicate that the Middleton Island Yakataga Formation is younger than the Tachilni Formation of the Alaska Peninsula, and that it is no older than the Beringian transgression. The following species, which occur, or are questionably reported, in the Middle- ton Island section, make their earliest appearance in strata of Beringian age: Astarte elliptica (Brown), Astarte mon- taguii (Dillwyn), Astarte rollandi Bernardi, Buccinum glaciale Linnaeus, Buccinum glaciale parallelum Dall, Buccinum physematum Dall, Buccinum plectrum Stimp- son, Epitonium greenlandicum (Perry), Plicifusus kroyert (Moller), Polinices pallidus (Broderip & Sowerby), and Tachyrhynchus erosus (Couthouy). Although the lower age limit for this fauna is readily established with the fossil Mollusca, recognition of the upper age limit depends upon the presence of extinct spe- cies. Monographic treatment of the pectinids by MAcNEIL (1967) and the neptuneids by NELson (1974) make pos- sible the recognition of the only extinct taxa so far known in the Middleton Island Yakataga Formation. The follow- ing extinct species have been recognized: Chlamys hana- ishiensis amchitkana MacNeil, Chlamys islandica kanagae MacNeil, Chlamys cf. C. picoensis chinkopensis Masuda & Sawada, Chlamys pseudoislandica plafkert MacNeil, Chla- mys coatsi middletonensts MacNeil, Chlamys tugidakensis MacNeil, and Neptunea lyrata altispira Gabb. These taxa indicate an age no younger than the middle Pleistocene Kotzebuan or Einahnuhtan transgressions (Hopkins, 1973), but the paleomagnetic evidence of an age no younger than the early Pleistocene part of the Matu- Vol. 21; No. 2 yama reversed polarity epoch (Anvilian transgression) is thought to be the most reliable criterion for dating this sequence. Although early collections studied by MAcNEIL (1967) showed Chlamys tugidakensis to range only through the lower 762 m of the Middleton Island section, it is now re- corded to approximately 1109 m above the base, and there- fore almost throughout the entire stratigraphic succession, a situation also found at Tugidak. In short, both the Mid- dleton Island Yakataga Formation and the Tugidak For- mation belong almost entirely to the range zone of Chlamys tugidakensis and this species appears to continue across the Pliocene-Pleistocene boundary. Strata of the upper Yaka- taga Formation in the Chaix Hills of the Lituya District also belong to the range zone of Chlamys tugidakensis. Chlamys cf. C. picoensis chinkopensis occurs from near the base of the Middleton Island section to about 732m above the base. This species also is known from a locality 97-5 m below the top of the Tugidak Formation, which suggests that the top of the Tugidak Formation and some part of the basal Middleton Island Yakataga Formation section may be coeval. The absence of species of Astarte in the Middleton Island section, which are restricted to the Beringian-Anvilian interval in the Bering Sea area and at Tugidak, also suggests that much of the Middleton Is- land section may be younger than the Tugidak Formation. Analysis of the Middleton Island assemblages shows 8 with lower depth limits of 50m, 3 with depth limits at 55, m, 11 with limits no deeper than 74 m, and one each lim- ited to water no deeper than 75m, 119m, and 136m. Five assemblages appear to be limited to water no deeper or no shallower than about 50m. Analysis of the Middleton Island molluscan assemblages also shows 7 with water no shallower than 15 or 18m, 5 limited to water no shallower than depths between 21 and 46m, and most significantly, 16 assemblages limited to water no shallower than 50 m. One assemblage appears to be limited to depths no shallower than 55 m, 64m, 76m, and 94m. To summarize, these data suggest that most assemblages lived between 50 and 74m, and that locally the bottom could have been as shallow as 15 or 18m, and as deep as 136 m at one stratigraphic level near the base of the ex- posed section. The bulk of the data therefore suggests depths in the lower part of the inner neritic or top of the outer neritic depth zones. The data also suggest that water depths were generally shallower at Middleton Island than at Tugidak, and this appears to have been a significant fac- tor in determining the somewhat different faunas of the two areas. Mollusks from the Middleton Island Yakataga Forma- tion represent cold-water conditions, colder than exist in THE VELIGER Page 183 the Gulf of Alaska today. Although most of the species are endemic to the North Pacific, my data show that about 35% (included with the endemics) are circumboreal taxa that range throughout the Arctic or into the North Atlan- tic. Eight species found in the Middleton Island strata are not presently known to live near Middleton, but are con- fined to areas farther west along the Aleutians or farther north in the Bering Sea. These cold-water extralimital taxa are: Nuculana pernula (Moller), Yoldia cf. Y. arctica (Gray), Beringius friele: Dall, Buccinum tenue lyperum Dall, Volutopsius cf. V. middendorffi (Dall), and Volu- topsius cf. V. simplex Dall. Two species in the Yakataga Formation at Middleton Island have not been reported liv- ing this far north. These two southern extralimital species are Laqueus californianus (Koch) (known as far north as British Columbia), and Taranis strongi (Arnold) (known to 55° N latitude at Forrester Island, Alaska). In summary, the evidence suggests that the Gulf of Alaska was indeed colder than at present during deposition of the Middleton Island Yakataga Formation. As in the Tugidak fauna, most of the Middleton Island Yakataga fauna 1s of North Pacific origin. Approximately 75% of the taxa have modern North Pacific distributions suggesting no closer relationship to Asia than to North America. Among the circumboreal species, which consti- tute about 35% (included with the endemics), the great majority originated in the Pacific (DURHAM & MACNEIL, 1967). Astarte elliptica (Brown) and Astarte montaguii (Dillwyn) are faunal elements of Atlantic origin which sug- gest that the Bering Strait was open during or prior to depo- sition of the Middleton Island strata. The pectinid fauna is of North Pacific origin, although it is most closely related to- forms known in Japan; at most, about 5% of the fauna can be considered to show Asiatic zoogeographic affinities. Ap- proximately 18% of the fauna suggests faunal relation- ships with western North America, and about 2% may be considered cosmopolitan. One species, Chlamys islandica kanagae MacNeil (2% of the fauna; included with the en- demics) appears ancestral to a North Atlantic taxon. SUMMARY anp CONCLUSIONS Tables 1 and 2 summarize data on the mollusk-bearing stratigraphic units discussed; Figure 2 also shows suggested correlations among them. Analysis of these data permit several conclusions: 1. Neogene thermal histories of the western and north- eastern Gulf of Alaska were distinctly different from each other (ApDICOTT, 1969). The western Gulf had a climatic history similar to that of the conterminous Page 184 THE VELIGER Vol. 21; No. 2 Table 1 Summary of data for some western Gulf of Alaska mollusk-bearing stratigraphic units. Because of dubious specific and generic identi- fications, the number of systematic entries on the faunal lists used for analysis differs from the number of taxa actually present. The number of taxa amenable to zoogeographic analysis is given in parentheses Western Gulf of Alaska Zoogeographic No. of systematic affinities | entries Formation Thickness | Age Water depth Temperature | (Figures very approximate) |(No. taxa analyzed) Tugidak Formation | 1500m Beringian to upper outer cold Asiatic: 5% | Anvilian neritic North American: 10% 98 transgressions Endemic: 83% (Circumboreal: 46%) (78) Cosmopolitan: 1% + == } + Tachilni Formation | 61m + , Graysian shallow subtidal | cool temperate Asiatic: 16% (“Jacalitos” to to inner neritic North American: 21% 20 “Etchegoin”) Endemic: 63% | (Pre-circumboreal: 26%) el ———————————t Upper Unnamed 1525m_ | Wishkahan shallow subtidal | warm temperate | Asiatic: 21% Member of the Bear! to pos- | to inner neritic North American: 48% 48 Lake Formation sibly | Endemic: 31% 3000 m(?) (Pre-circumboreal: 10%) Ta POP TEI OAD tae Me Gane pale Unga Conglomerate] 244m late Newportian | subaerial to warm temperate | Asiatic: 35% Member of the Bear to early | upper outer North American: 24% 25 Lake Formation Wishkahan neritic Endemic: 41% | — | Narrow Cape 700m | Newportian shallow subtidal | warm temperate, | Asiatic: 33% Formation | to outer neritic perhaps near | North American: 53% [Fauna includes outer tropical Endemic: 13% about 80 taxa, | b boundary | (Pre-circumboreal: 3%) however] (30) eae Narrow Cape 210m Juanian outer neritic Near cool Asiatic: 32% Formation of temperate-mild | North American: 35% 57 Sitkinak Island temperate Endemic: 30% | boundary (Pre-circumboreal: 14%) (37) Cosmopolitan: 3% western United States. In contrast, Miocene temper- 3. Asiatic faunal affinities are generally greater in the atures of the northeastern Gulf were cooler and ap- western Gulf area than in the northeastern area; pear to be related to local glaciation which began both show significant declines during Miocene time. about 20 million years ago (PLAFKER & ADDICOTT, 4. North American faunal affinities are most pro- 1976). nounced during periods of relatively warm water 2. Sea surface temperatures in the northeast Gulf were conditions as represented by the faunas of the Poul as warm as the mild temperate zone when glaciation Creek, Narrow Cape, and upper Bear Lake Forma- began; temperatures cooler than the present cool tions. Substantially fewer taxa with North American temperate conditions were not reached before late affinities are recorded in the faunas of the Yakataga, Pliocene (Beringian) time. The thermal history pro- Tachilni, and Tugidak Formations; these decreases posed here differs significantly from those of BANDY are correlated with cooler water temperatures and et al. (1969) and KANNo (1971) who inferred cold- increased provincialism and faunal endemism. water (Arctic) conditions throughout Yakataga time. Northeastern Gulf of Alaska Vol. 21; No. 2 THE VELIGER Page 185 Table 2 Summary of data for some northeastern Gulf of Alaska mollusk- bearing stratigraphic units. Because of dubious specific and generic identifications, the number of systematic entries on the faunal lists used for analysis differs from the number of taxa actually present. The number of taxa amenable to zoogeographic analysis is given in parentheses. Zoogeographic Formation Thickness Age Water depth Yakataga Formation| 1181m Anvilian lower inner at Middleton Island transgression neritic to upper outer neritic; occasionally shallower Yakataga | Anvilian? trans- intertidal Formation gression at top and shallow (Mainland, | (Chaix Hills) subtidal to Kayak and zs | inner Wingham .. 5 | neritic in Islands) g E upper part | ~5000m | Newportian at = = | lower inner} including] base at Yakataga & 2 _ neritic to Middle- | Reef = = | outer nerit- ton Is. 8.9 | ic at Yaka- o = beds yf | taga Reef 3S Juanian? and = | upper Poul Creek Formation 1859m Pillarian at base on Kayak Island Echinophona dalli zone (upper Galvinian) to Pillarian bathyal at base on Kayak Is. lower inner Neritic to outer neritic 5. In general, species that are locally endemic or en- demic to the high latitude perimeter of the North Pacific are more abundant in the northeast Gulf of Alaska area. Faunal endemism is at a minimum dur- ing warm-water conditions. 6. Some taxa appeared in the Gulf of Alaska prior to the late Pliocene (Beringian) opening of the Bering Strait, and later achieved circumboreal distributions or gave rise to taxa that did. These ‘‘pre-circum- boreal” taxa are therefore a special category of North Pacific endemic species. The earliest of these taxa appear in Juanian (late Oligocene) strata of the Gulf. | warm temperate Temperature cold affinities (Figures very approximate) Asiatic: 5% North American: 18% No. of systematic entries (No. taxa analyzed) Endemic: 75% 115 (Circumboreal: 35%) (Pre-circumboreal: 2%) (60) Cosmopolitan: 2% | cold at top? Asiatic: 10% cool temperate North American: 26% 42 in upper part Endemic: 62% (Pre-circumboreal and (39) Circumboreal: 26%) Cosmopolitan: 3% near mild tem- Asiatic: 12% perate-cool North American: 28% 48 12] temperate Endemic: 58% boundary at (Pre-circumboreal: 12%) (43) (104) Yakatage Reef Cosmopolitan: 2% mild temperate | Asiatic: 41% at base on North American: 14% 31 Kayak Island Endemic: 45% (Pre-circumboreal: 9%) (22) mild temperate | Asiatic: 18% | North American: 52% 107 Endemic: 30% (Pre-circumboreal: 6%) They increase upsection in cool-water units, but de- crease during warm-water conditions. 7. Endemic (includes “pre-circumboreal” and circum- boreal) taxa increase upsection in the Yakataga For- mation to a maximum of 75% of the Middleton Island fauna. This group increases upsection in the western Gulf to 83% in the Tugidak Formation. These data underscore the difficulty in correlating the late Neogene and Quaternary molluscan faunas of the Gulf with conterminous western United States faunas. THE VELIGER Vol. 21; No. 2 CALIFORNIA ALASKA BENTHIC "FORAM" ane Pee BERING SEA | Cape |PORT MOLLER, | KODIAK, MIDDLETON, | “IKATAGA- STAGES TRANSGRESSIONS | TACHIINI | UNGA,POPOF IS. | rpinity isis) KAYAK ISU’S| pistricts andi TTT) | Loon Bpupagues "Etchegoin Jacalifos. eae Bear Lake Fm. (upper) 2 EP. } Yakataga Fm. Margaritan Narrow Cape Fm.Kodiak MIOCENE 2 © Marine Beds of Unga Cgl. Mbr. Saucesion --—--—— Pillarian "Narrow Cape" Ps Fm.Sitkinok | Zemorrian b ! t i} SRS Galvinian i h Richard C. Allison, {977 z z | z| z | N| @ N Sy v n Figure 2 Tentative correlations of major late Paleogene to Pleistocene mollusk-bearing stratigraphic units of the Gulf of Alaska Region. Radi- ometric time-scale, epochs, planktonic zones, and California benthic foraminiferstagesadapted from BERGGREN & VAN CouvERING (1974: figs. 1 and 15) and modified by reference to EVERENDEN et. al. (1964), Lipps (1967), TURNER (1970), BERGGREN (1972), Horn- ADAY (1972), Lipps & KatisKy (1972), STAINFORTH et al. (1975), and Howe.t (1976). The California benthic chronology is, how- ever, tied to the planktonic zones and radiometric time-scale by relatively few control points, Several authors (e. g., INGLE, 1967; BANDy, 1972; and Prerce, 1972) have suggested that some California benthic foraminifer stage boundaries may be time-transgressive, there- by further complicating correlations. The West Coast molluscan stage chronologies are adapted from Weaver et al. (1944), DurHam et al. (1954), ADEGOKE (1969), AppicoTtr (1972), ARMENTROUT (1975), and Appicotr (1976). The molluscan stages are somewhat loosely tied to the benthic foraminifer stages and to the North American land-mammal ages for which some radiometric dates are available (EVERENDEN e¢ al., 1964, and Savacz, 1972). The Alaskan molluscan faunas have been correlated with the West Coast molluscan chronologies and the Bering Sea transgres- sion cycles (Hopkins, 1967). Vertical ruling indicates either hiatus, or absence of major mollusk-bearing stratigraphic units. Thick black lines at the sides of some chronostratigraphic boundaries indicate the probable range of accuracy of the boundary position as determined by radiometric dating. 8. Analysis of the biogeographic affinities of the faunas suggests that the first exchange of North Pacific and North Atlantic taxa through the Bering Strait may have been during the late Miocene, perhaps at the beginning of Wishkahan time some 10 to 13 million years ago (Hopkins, 1967b: 454). The later Bering- ian (late Pliocene) opening of the Bering Strait per- mitted many North Pacific taxa to migrate into the North Atlantic (Hopkins, loc. cit.) and allowed a lesser number of North Atlantic and boreal species Vol. 21; No. 2 THE VELIGER Page 187 to reach the Bering Sea and North Pacific (DURHAM & MACNEIL, 1967). ACKNOWLEDGMENTS I am indebted to the University of Alaska for sabbatical leave during the 1975-76 academic year when much of this research was conducted. Dr. Warren O. Addicott arranged for my use of the facilities and Alaskan fossil collections of the U.S. Geological Survey in Menlo Park, California, and has been a valued advisor in many aspects of this study. I am grateful to Dr. Louie Marincovich of the U.S. Geolog- ical Survey for his help with this project and to Catherine Ariey of the Atlantic-Richfield Company for information from her Master of Science thesis research work on the upper Poul Creek and lower Yakataga Formations of the northeastern Gulf of Alaska. I am also indebted to the Geo- physical Institute of the University of Alaska for support of this research project. The manuscript has been reviewed by Donald M. Triplehorn, Addicott, and Marincovich. Financial support from the Solid-Earth Sciences Program of the University of Alaska is gratefully acknowledged. Literature Cited Appicott, WARREN OLIvER 1969. ‘Tertiary climatic change in the marginal northeastern Pacific Ocean. Science 165: 583 - 586; 3 text figs. 1971. Tertiary mollusks of Alaska: an annotated bibliography. U. S. Geol. Survey Bull. 1343: 1-30; 3 text figs. 1972. Provincial middle and late Tertiary molluscan stages, Temblor Range, California. In Symposium on Miocene biostratigraphy of California. Soc. Econ. Paleon. Mineral., Pacif. Section, Bakersfield, Ca- lif.: 1-28; plts. 1-4 1974. Giant pectinids of the eastern North Pacific margin: signifi- cance in Neogene zoogeography and chronostratigraphy. Journ. Paleon. 48 (1): 180-194; 2 plts.; 7 text figs. 1976. Neogene molluscan stages of Oregon and Washington. Soc. Econ. Paleon. Mineral., Pacif. Sect., Neogene Symposium, San Fran- cisco, Calif.: 95-115; 5 plts.; 6 text figs.; 1 table 1976b. On the significance of the bivalve! Acila gettysburgensts (Rea- gan) in middle Tertiary chronostratigraphy of the Pacific Coast. The Veliger 19 (2): 121-124; 3 text figs. (1 October 1976) Appicott, WARREN O Liver, SABuRO Kanno, Kenji SAKOMOTO & Don J. Mivrer 1971. Clark’s Tertiary molluscan types from the Yakataga district, Gulf of Alaska. U.S. Geol. Survey Prof. Paper 750C: C18 - C33; 2 tables; 6 text figs. ADEGOKE, OLUWAFEYISOLA SYLVESTER 1967. New and oldest records of pelecypod Mya from ere North America, south of Alaska. The Nautilus 80 (3): 9; 3 text figs. (21 iit 1976) 1969. Stratigraphy and paleontology of the marine Neogene forma- tions of the Coalinga region, California. Univ. Calif; Publ., Geol. Sci. 80: 1-241; 13 plts.; text figs. 1-6A; maps 1-3A ALuIson, RicHarp CasEz 1973. Marine paleoclimatology and paleoecology of a Pleistocene in- vertebrate fauna from Amchitka Island, Aleutian Islands, Alaska. Palaeogeogr., Palaeoclim., Palaeoecol. 13: 15-48; 3 textfigs.; 9 tab. 1976. Late Oligocene through Pleistocene molluscan faunas in the Gulf of Alaska region. Abstr. Pap., First Internat. Congr. Pacif. Neo- gene Stratigraphy. Tokyo, Japan, May 16-21, 1976: 10-13. Repr. Proc. First Internat. Congr. Pacif. Neog. Stratigraphy 313-316; 1 text fig., 1 table. Tokyo, Japan, 1977 A.uison, RicHarp Case & WaRREN O.iver AppicotT 1973. The Mytilus middendorffi group (Bivalvia) of the North ee Miocene (abstr.). Geol. Soc. Amer., Abstr. with Programs 5 (1): 1976. The North Pacific Miocene record of Mytilus (Biieassritoay a new subgenus of Bivalvia. U.S. Geol. Surv. Prof. Paper 962: I - 22; 3 plts.; 3 text figs. ARMENTROUT, Joun M. 1975. Molluscan biostratigraphy of the Lincoln Creek Formation, southwest Washington. In Soc. Econ. Paleon. Mineral., Pacif. Sect. Paleogene Symposium and selected tech. papers, Long Beach, Calif. : 14-48; 7 text figs. Banpy, Orvitte L. 1968. Paleoclimatology and Neogene planktonic foraminiferal zona- tion. Committ. Mediterr. Neog. Stratigr., Proc. IV Sess., Bologna 1967 - G. Geol. 2 (KXXV) (II): 277-290 1972. Late Paleogene-Neogene planktonic biostratigraphy and some geologic implications, California. In Sympos. Miocene biostrat. Calif. Soc. Econ. Paleon. Mineral. Pacif. Section, Bakersfield, Calif.: 37-515; 3 text figs. Banpy, Orvitte L., E. ANN Butter & Ramit C. WricHT 1969. Alaskan upper Miocene marine glacial deposits and the Turbo- votalia pachyderma datum plane. Science 166: 607-609; 2 figs. BERGGREN, WILLIAM ALFRED 1972. A Cenozoic time-scale — some implications for regional geo- logy and paleobiogeography. Lethaia 5: 195-215; 9 text figs. BerccREN, WILLIAM ALFRED & JOHN A. VAN CouvERING 1974. Neogene biostratigraphy, geochronology, and paleoclimatology of the last 15 million years in marine and continental sequences. Palaeogeogr., Palaeoclim., Palaeoecol. 16 (1/2): 1-216; 15 text figs.; 12 tables Burk, CreioHTon A. 1965. Geology of the Alaska Peninsula-island arc and continental margin. Geol. Soc. Amer. Mem. 99 (1): 250 pp.; 8 plts.; 28 text figs.; 1 table CHAMBERLAIN, J. L. & F STEARNS 1963. A geographic study of the clam Spisule polynyma (Stimpson). Amer. Geog. Soc., serial Atlas, mar. environ., Folio 3: 12 pp. Crark, Bruce L. 1932. Fauna of the Poul and Yakataga Formations (upper Oligocene) of southern Alaska. Geol. Soc. Amer. Bull. 43: 797-846; plts. 14-21; 1 text. fig. Darzi, Wirtiam Hzarey « Girnert D. Harris 1892. Correlation papers. Neocene. 5-349; plts. 1-4; 43 text figs. DurHam, JoHN Wyatt 1944. Megafaunal zones of the Oligocene of northwestern Washington. Univ. Calif. Publ. Dept. Geol. Sci. Bull. 27 (5): 101-212; pits. 13-18 DuruaM, Jon Wyatt, Ricwarp H. JanNs « Donan E. Savace 1954. Marine—nonmarine relationships in the Cenozoic section of California. Calif. State Div. Mines, Bull. 170: (1): 59-713 4 figs. Duruam, Jonn Wyatt @ Francis STEARNS MacNEIL 1967. Cenozoic migrations of marine invertebrates through the Bering Strait region. In: D. M. Hopxins (ed.) The Bering Land Bridge. Stanford, Calif:: 326-349; 4 tables Eakins, GirsBert R. 1970. A petrified forest on Unga Island, Alaska. Div. Mines Geol., Spec. Rep. 3: 1-19; 16 text figs. EvERENDEN, Jack F, Donatp E. Savacz, Garniss H. Curtis & Gweon T. James 1964. Potassium-Argon dates and the Cenozoic mammalian chrono- logy of North America. Amer. Journ. Sci. 262: 145-198; 1 text Bull. U.S. Geol. Surv. 84: State of Alaska, fig.; 7 tables Harz, Crarence A., Jr. , 1964. Shallow-water marine climates and molluscan provinces. Ecology 45 (2): 226-234; 6 text figs.; 2 tables Hopkins, Davip Moopy 1967 . Quaternary marine transgressions in Alaska. In: D. M. Hopkins (ed.), The Bering Land Bridge. Stanford, Calif:: 47 - 90; 5 text figs; 2 tables 1967b. The Cenozoic history of Beringia— a synthesis. In: D. M. Hopkins (ed.): The Bering Land Bridge. Stanford, Calif: 451 - 484; 4 text figs. 1973- Sea level history in Beringia during the past 250000 years. Quaternary Research g: 520-540; 10 text figs.; 1 table Hoprxins, Davm Moopy, Ropert W. Roranp, Ronatp E. EcHoLs & Pace C. VALENTINE 1974. An Anvilian (early Pleistocene) marine fauna from western Seward Peninsula, Alaska. Quatern. Research 4: 441 - 470; 4 plts.; 7 text figs.; 3 tables Page 188 Hornapay, Gorpon R. 1972. Oligocene smaller foraminifera associated with an occurrence of Miogypsina in California. Journ. Foram. Res. 2(1): 35-46; 2 plts.; 2 text figs. Howe tr, Davp G. 1976. A review of the estimates for the radiometric ages for the Reli- zian stage of the Pacific Coast. Soc. Econ. Paleon. Mineral., Pa- cif. Coast sect., Neogene Symp. vol., San Francisco, Calif: 13-15; 2 text figs. IncLE, James Cuesney, Jr. 1967. Foraminiferal biofacies variation and the Miocene-Pliocene boundary in southern California, Bull. Amer. Paleon. 52 (236): 217 - 394 Kanno, SaBuro 1971. Tertiary molluscan fauna from the Yakataga district and ad- jacent areas of southern Alaska. Palaeon. Soc. Japan, Spec. Paper no. 16: 1-154; 18 plts.; 20 text figs.; 7 tables 1973. Japanese Tertiary cassidids (Gastropoda) and their related mollusks from the west coast of North America. Sci. Rept. Tohoku Univ.. Sendai, Japan (2) (Hatai Memorial vol.) (6): 217 - 233; plts. 19-22; 5 text figs.; 2 tables Lipes, Jere Henry 1967. Planktonic foraminifera, intercontinental correlation and age of California mid-Cenozoic microfaunal stages. Journ. Paleon. 41 (4): 994-1005; 2 plts.; 5 text figs. MacNeil, Francis STEARNS 1961. Lituyapecten (new subgenus of Patinopecten) from Alaska and California. U.S. Geol. Surv. Prof. Paper $54-J: 225-239; plts. 35-46 1965. Evolution and distribution of the genus Mya, and Tertiary migrations of Mollusca. U. S. Geol. Surv. Prof. Paper 483-G: G1 -G4g; 11 plts.; 3 text figs. 1967. Cenozoic pectinids of Alaska, Iceland, and other northern re- gions. U.S. Geol. Surv. Prof. Paper 553: 1-53; 25 plts. 1970. New Pliocene Chlamys (Swiftopecten) and Beringius from the Alaska Peninsula. The Nautilus 84 (2): 69-74; 2 text figs. 1973. Marine fossils from the Unga Conglomerate Member of the Bear Lake Formation, Cape Aliaskin, Alaska Peninsula, Alaska. Sci. Rept. Tohoku Univ., Sendai (2) (Hatai Memorial vol.) (6): 117-123; 2 plts. MacNeil, Francis Stearns, Jack A. Wore, DonaLp J. MILLER & Davip M. Hopkins 1961. Correlation of Tertiary formations of Alaska. Amer. As- soc. Petrol. Geol. Bull. 45 (11): 1801-1809; 2 text figs. Masupa, K6éicH1r6 & WarRREN OLiver ApDICoTT. 1970. On Pecten (Amusium) condoni Hertlein from the west coast of North America. The Veliger 19 (2): 153-156; 1 pit. (1 October 1970) Mixzer, Donan J. 1953- Late Cenozoic marine glacial sediments and marine terraces of Middleton Island, Alaska. Journ. Geol. 61: 17-40; 4 text figs.; 2 pits.; 7 tables 1957. Geology of the southeastern part of the Robinson Mountains, Yakataga district, Alaska. U.S. Geol. Surv. Oil & Gas Invest. Map OM-187: 2 sheets 1961. Stratigraphic occurrence of Lituyapecten in Alaska. U. S. Geol. Surv. Prof. Paper 354-K: 241-249; 2 text figs. 1971. Geology of the Yakataga district, Gulf of Alaska Tertiary Province, Alaska. U. S. Geol. Surv. Misc. Geol. Invest. Map I-610, scale 1 : 125000 Moore, Georce W. 1969. New formations on Kodiak and adjacent islands, Alaska. U.S. Geol. Surv. Bull. 1274-A: A27-A35; fig. 2 Weaver, Cuarues E. (chairman) et al. THE VELIGER Vol. 21; No. 2 Netson, Ciirrorp MELVIN 1974. Evolution of the late Cenozoic gastropod Neptunea (Gastropoda: Buccinacea). ix+802 pp.; 66 plts.; 17 text figs; appendix A, B (unpubl. Ph. D. thesis, Univ. Calif, Berkeley) OcxEeLmann, W. K. 1954. On the interrelationship and zoogeography of northern species of Yoldia Moller, s. str. (Mollusca, Fam. Ledidae) with a new sub- species. Meddel. Gronland 107 (7): 1-91; 2 plts.; text figs.; 10 tables ParKER, PIERRE 1949. Fossil and Recent species of the pelecypod genera Chione and Securella from the Pacific Coast. Journ. Paleon. 2g (6): 577 - 593: plts. 89 - 95 Pierce, RicHarp L. 1972. Revaluation of the late Miocene biostratigraphy of California; summary of evidence. In Symposium on Miocene biostratigraphy of California. Soc. Econ. Paleon. Mineral., Pacif. Sect., Bakersfield, Calif:: 334-340; 5 text figs. PLAFKER, GEORGE 1971. Possible future petroleum resources of Pacific-margin Tertiary basin, Alaska. Amer. Assoc. Petrol. Geol. Mem. 15: 120-196; 3 text figs. 1974. Preliminary geologic map of Kayak and Wingham islands, A- laska. U. S. Geol. Surv. open-file map 74-82, scale 1:31 680 PLaFKerR, Gzorce & WARREN Otiver AppIcoTT 1976. | Glaciomarine deposits of Miocene through Holocene age in the Yakataga Formation along the Gulf of Alaska margin, Alaska. U.S. Geol. Surv. open-file report 76-84: 1-36; 6 text figs.; 1 table. Reprinted, Proc. Sympos. on Recent and Ancient sedimentary environ- ments in Alaska, pp. Q1 - Q23, Alaska Geol. Soc., Anchorage, Alaska, 1976 Rav, WELDon W. 1963. Foraminifera from the upper part of the Poul Creek Formation of southeastern Alaska. Cushman Found. Foraminif. Res. Contr., 14 (4): 135-145; 2 plts.; 1 text fig. REPENNING, CnHar_es A. 1976. Enhydra and Enhydriodon from the Pacific coast of North A- merica. U.S. Geol. Surv. Journ. Res. 4 (3): 305-315; 3 figs. Savace, Donatp E. 1972. Miocene vertebrate geochronology of the west coast of North America, Part I. In Symposium on Miocene biostratigraphy of California. Soc. Econ. Paleon. Mineral., Pacif: Sect., Bakersfield, Calif: 125-145; 4 text figs; : map StainrorTH, R. M., J. L. Lams, Hanspeter Lutersacuer, J. H. Bearp a R. M. Jerrorps 1975- Cenozoic planktonic foraminiferal zonation and characteristics of index forms. Univ. Kansas Paleon. Contr., article 62: 1 - 162e; figs. 1 - 29; 9 tables [Appendix in separate volume] TaviaFerRO, Nicuoras L. 1932. Geology of the Yakataga, Katalla, and Nichawak districts, Al- aska. Geol. Soc. Amer. Bull. 43: 749 - 782; 14 text figs.; 1 table Turner, Donatp L. 1970. Potassium-Argon dating of Pacific Coast Miocene foraminiferal stages. Geol. Soc. Amer. Spec. Paper 124: 91-129; 10 text figs.; 3 tables Waoner, Caro D. 1974. Fossil and Recent sand dollar echinoids of Alaska. Journ. Paleon 48 (1): 105-123; 3 plts.; 2 text figs. Wa.pron, Howarp H. 1961. Geologic reconnaissance of Frosty Peak Volcano and vicinity, Alaska. U. S. Geol. Surv. Bull. 1028-T: 677 - 708; plt. 79; fig. 104 1944. Correlation of the marine Cenozoic formations of western North America. Geol. Soc. Amer. Bull. 55 (5): 569-598; chart no. i1 Vol. 21; No. 2 THE VELIGER Page 189 World-Wide Biostratigraphic Correlation Based on Turritellid Phylogeny TAMIO KOTAKA Institute of Geology and Paleontology. Tohoku University, Sendai, Japan (7 Text figures) INTRODUCTION THE FAMILY TuRRITELLIDAE includes several taxa that have generally restricted dispersal ability because of their very short veliger stage and ovoviviparity in some cases (LeBour, 1933; MARWICK, 1971; MERRIAM, 1941; PALMER, 1958, 1961; PEILE, 1922), therefore, genetically isolated groups must have diverged widely from each other during the course of Cretaceous and Tertiary time. In natural classification, this should be reflected by numerous local- ized genera and subgenera. According to MARWICK (1957), more than a thousand fossil and living species and sub- species of turritellas distributed in more than 40 genera and subgenera of 5 subfamilies are known from all over the world. Among 5 subfamilies of the Turritellidae, the Tur- ritellinae is the largest and has a world wide distribution in time and space. Even though their divergence is fairly wide, their shell morphology is, fortunately enough, very simple, and con- sists only of spiral cords or seldom spiral beads, and growth- lines on the shell surface, which can be traced back into the early stage of shell growth, the ontogeny of individual specimens. Since L. GuILLAuME published “Essai sur la classifica- tion des turritelles, ainsi que sur leur evolution et leurs migrations, depuis le debut des temps tertiaires’’ in 1924, several monographic works on the Tertiary turritellas have appeared from several regions of the world. Most authors have tried to establish the phylogenetic trends of regional and/or local groups, for example, ALLISON « ADE- GOKE (1960), BADEN-POWELL (1955), BowLEs (1939), IDA (1952), KOTAKA (1954, 1959, 1960), MARWICK (1957) and MER- RIAM (1941) and others. Among these, the Turritella (Neo- haustator) saishuensis-andenensis Bioseries of Japan estab- lished by Kotaka (op. cit.), the Zeacolpus (Stiracolpus) kaawaensis-delli Bioseries (Group auct.) in New Zealand by Marwick (op. cit.), the Turritella moodyi-cooperi Bio- series (== Stock auct.) of California by MERRIAM (op. cit.) and the Turritella (Haustator) tricarinata-communis Bio- series (— Series auct.) of Britain and the Mediterranean by BADEN-POWELL (op. cit.) are the most interesting to the writer from the viewpoint of biostratigraphic correlation mainly by means of respective turritellid bioseries. Previously, the writer (KOTAKA, 1960) pointed out that there is fairly close similarity between each bioseries men- tioned above, and concluded: “. .. the process of the transformation correspond to each other with high similarity, and can be designated as parallel evolution represented by the appearance and strengthening in the spiral sculpture, and if the age determinations settled by the respective authors are correct, the similar age of the beginning of the transformation in sculpture is recognized . . . itis noticeable that the complication in sculpture of these tur- ritellid series took place during the late Pliocene and the early Pleistocene, a particular stage in the geological history:’ Recent advances in precise biostratigraphic studies of the regions and paleontology of main taxa of the Cenozoic Era, for example, foraminifers, radiolarians, mollusks and diatoms, have called the writer’s attention again to the tur- ritellid bioseries of the late Cenozoic. And the writer here proposes to establish the world-wide biostratigraphic cor- relation and age determination of the late Cenozoic based on the turritellid bioseries. BRIEF NOTE on BIOSERIES In order to facilitate the descriptions of change in spiral ornamentation from species to species in respective bio- series, the writer followed a system of notation previously proposed by Marwick (1957) and emended by Kotaka (1959: 59-60) as shown in Figure 1 and the following lines. “The first spiral generally appears as an angulation on about the adapical third of the whorl and sometimes this Page 190 THE VELIGER Vol. 21; No. 2 can be combined. For example, the notation of the typical Turritella saishuensis Yokoyama is shown as (C, Bo s, As) and the typical Zeacolpus kaawaensis (Laws) as (u C B Ar). Fur- ther, the tertiary spirals appearing in the interspaces between each preceding primary and secondary spirals are shown by a dot (.). {f the tertiary spirals are so prominent that they must be noted, then the tertiary spiral appears abapical or adapical to the secondary spiral r is designated r, or r. respectively, orie Figure 1 to secondary spiral s is s, or so, and so on. In some cases, the spiral threads or striae appear on the surface of preceding spiral A, they may be denoted A, and so on.” Notation of spiral cord I. Turritella (Neohaustator) saishuensis — andenensis spiral seems to make the protoconch merge into the first Bioseries neanic whorls in several forms of the Japanese and New Zea- land turritellas, this is designated primary spiral C. The one which appears on about the mid-whorl and the one abapical third of the whorl are designated B and A respectively. A and D are the peri-basal ones. The secondary spirals generally Among more than 60 fossil and living species and sub- species of turritellas known from the Japanese Islands and surrounding waters, Turritella (Neohaustator) saishu- appear abapical to A, between A and B, between B and C, ensis Yokoyama has the widest geographic distribution in and adapical to C, these are denoted by the small letters r, s, the late Cenozoic of the Japan Sea borderland. Since Yoko- t and u respectively. When the primary spirals become weak, yama described this species from the Pliocene deposits of the notation of the primary spirals A, B, C and D are changed . Cheju Islands of Korea in 1923, the species AAS long been DEM ada ater a uaa te ce Ren a thought to be an important index fossil of the Pliocene, rival the primary ones, then the secondary spirals, r, s, t and u are changed into capital letters R, $, T and U. Owing to the especially in the oil fields of the Japan Sea borderland, but necessity the notation in the order of appearance of the spirals subsequent authors (IA, 1952; IKEBE, 1940; KOTAKA, 1954 Table 1 The regional and zonal variants in sculpture of Turritella cooperi Carpenter and related species Species Age Notation Merriam’s Pl. & fig. Turritella cooperi Carpenter Recent (ucbsa) pit. 34, fig. 9. (Gicaibeale)) pit. 33, fig. 15. (CBA) pit. 33, fig. 16. (CbA) pit. 33, fig. 14. Timm’s Point (Cbsa) pit. 33, fig. 4. (CBA) pit. 35, fig. 14. (dCA) pit. 33, fig. 3. Santa Barbara (CBA) pit. 35, fig. 15. (cbA) plt. 34, fig. 13. Turnitella margarita Nomland Santa Margarita plt. 34, fig. 10. Turritella carrisaensis Anderson and Martin Santa Margarita pit. 34, fig. 3. (G.A.) pit. 34, fig. 2. (CA) pit. 34, fig. 1. (.A) pit. 34, fig. 5. (Smooth with shoulders at A and C) Turritella moodyi Applin (MS) Temblor (Smooth) pit. 33, figs. 5-7. pit. 34, fig. 6. Vol. 21; No. 2 and OrTukA, 1934) have split the species into subspecies and/or different species because of its fairly wide morpho- logic variation especially in spiral ornamentation. Based on the study of morphologic variation of the forms belong- ing to Turritella (Neohaustator) saishuensis (s.1.), KOTAKA (1954) summarized the phylogenic relationship between each form found in the Akita Oil Field. The relationship of the different forms in the bioseries of Turritella (Neohaustator) saishuensis is shown in Figure 4 with the illustration cf each typical form and the notation of spiral sculpture on the body-whorl. The spiral sculpture of the adult Turritella (Neohausta- tor) saishuensis (s. s.) is represented by (C Bs A), and this arrangement of the spirals is completed on about the ninth whorl. In some collection of T. (N.) saishuensis (s. 1.) from the latest Miocene, most specimens are sculptured without the secondaries, these are named T. (N.) saishuensis moti- dukii Otuka. The forms with the notation (C B A) and the forms with other secondary and tertiary spirals are seldom found with the specimens of T. (N.) satshuensis (s. s.) in the early Pliocene, but these are very few in number statisti- cally, for example, 7. (N.) satshuensis etigoensis Ida in the middle part of the Pliocene deposits of certain oil fields of Akita and Niigata Prefectures. In 7. (N.) otukai Kotaka, the ontogeny is more or less complicated, the spiral sculp- ture (C Bs A) is completed on about the eighth whorl, and the secondary spirals r, t and u appear to occur in each position, and the typical T. (N.) otuka: (uC T BS Ar) is completed on about the 15th whorl, and further the fine tertiary spirals sometimes appear. Further, T. (N.) otukai evolved to T. (N.) andenensis Otwka, in this case, the on- togeny is more complicated and accelerated. II. Zeacolpus (Stiracolpus) kaawaensis — delli Bioseries MARWICK (1957) published a monographic work on New Zealand Turritellidae and the species of Stiracolpus, and presented a suggested relationship of Stz:vacolpus species and subspecies. He noted specific relationships (Mar- WICK, Op. cit.: 24 - 25, 27). According to Marwick, even though slight changes in spire angle and whorl profile between each species exist, the intimate relationship be- tween one another can be drawn as shown in Figure 6, mainly based on the ontogenetic development and similar order of appearance in spiral sculpture. Concluding, Marwick’s kaawaensis-delli Bioseries dif- ferentiated into several branches in Pliocene and Pleisto- cene time, and according to his descriptions and illustra- tions, these differentiations are clearly represented by the appearance and strengthening of the secondary and ter- THE VELIGER Page 191 tiary spirals on each ancestral form so far as the surface ornamentation is concerned. III. Turritella moodyi — cooperi Bioseries Twelve stocks (= the bioseries of the present writer) of Cenozoic turritellas and a Cretaceous stock were proposed by C. W. MErRIAM (1941) from the Pacific coast of North America, based on close similarity of shell morphology with respect to 7) nuclear primary spiral rib compo- nent, 2) character of the growth-line trace, and _ 3) sec- ondary factors such as whorl profile, apical and pleural angles, and size and nodosity. Among the 13 bioseries, the Turritella coopert Stock of Merriam (— Turritella moodyi-cooperi Bioseries of the present writer) in the late Cenozoic (late Miocene to Recent) shows very similar pro- gressive development to those of Japan and New Zealand so far as surface ornamentation is concerned. Figure 2 is — Too 7 COQOST 33 ONS regarte/ “ Figure 2 Stratigraphic distribution and suggested lines of evolution in the Turritella moodyi — cooperi Bioseries (reproduced from Merriam, 1941) reproduced from MERRIAM (oP. cit.: 49), and the following is MERRIAM’S (of. cit.: 49) statement concerning the suc- cessive development of the Bioseries: “Throughout the long stratigraphic range of the species T. cooperi from uppermost Miocene to Recent, little succes- sive change is observed. In nearly all assemblages character- istic regional and zonal variants are found, but certain indi- viduals considered to be more or less typical of the species are found to range throughout, irrespective of stratigraphic or geographic position. In a given assemblage the specifically Page 192 typical forms may be present in limited numbers only, most individuals being regional or zonal types. It has been ob- served that, although a certain complex of variability may characterize the assemblage of a given locality, variants of this complex may occur in other horizons and regions spo- radically.’ The later half of the statement cited above contains a certain fundamental problem on the classification of fossil communities, and JoysEy (1956: 85-86) has explicitly ex- plained this problem as follows: “When dealing with fossils from a geological succession we are faced with a more difficult problem, since it is a contin- uous series of intermediates. In most cases stratigraphic breaks provide convenient discontinuities, but in the case of a con- tinuous record we are faced with the problem of subdivision for our own convenience. It is unavoidable that the position of the boundaries will be a matter for arbitrary choice, but it is relevant to discuss the direction in which the boundaries should be drawn, this being one of the main problems that the present symposium should endeavor to answer. The two alternative systems of classification are illustrated in Fig. 1, in which the numbers : to 3 represent a series of geological horizons in ascending order. On horizon the sym- bols a, b and c represent varieties within a single community in which the majority of individuals belong to the typical form ‘‘b” while “a” and ‘‘c’” represent the less common ex- tremes of variation. Similarly, at each horizon the middle letter represents the typical form, and the other symbols rep- resent less usual varieties at this horizon. Ascending the suc- cession, evolutionary change results in a progressive shift in the position of the mode of variation. We now have to decide the direction in which the series is to be subdivided. The boundaries may be defined either on a morphological basis, each of the species having a range, each of the species includ- ing the several varieties which formed part of the same com- munity. The size of the categories is arbitrary, and so, for convenience in the following discussion, the two different types of species will be referred to as the variety and the chronological subspecies, respectively:’ Careful study of the variants of Turritella cooperi (s. 1.) (Carpenter) based on sufficient specimens collected from the stratigraphic sequence of the Pacific coast of North America will give us a basis of recognition for the chrono- logical subspecies mentioned above. Although Merriam (1941) did not describe the details of the regional and zonal variants of Turritella cooperi and related species, the variants in surface sculpture taken from Merriam’s descriptions and illustrations have been tabu- lated (Koraka, 1960), and are reproduced here again. In Table 2 based on our collection of T. cooperi from the lower part of the San Pedro Formation of Deadman Island, California (IGPS coll. cat. no. 598) and Table 3 based on the specimens from the Palos Verdes Sand of San Pedro, THE VELIGER Vol. 21; No. 2 Table 2 Variation of the surface sculpture of Turritella cooperi Carpenter from the lower San Pedro Formation. (IGPS coll. cat. no. 598) Notation Number of Specimens (CbAr) 1 (CBs.A) 2 (C..A) 7 (C.A) 7 (CA) 3 Table 3 Variation of the surface sculpture of Turritella coopert Carpenter from the Palos Verdes Sand. (USGS coll. cat. no. M2017) Size of the last whorl in mm Notation (Cb.Ar) (Cb.A.) more than 10 less than 5 (BS California (USGS coll. no. M2017) give us rather precise data on sculptural variation. It seems to the writer very far from the structural study of a fossil community to draw an urgent conclusion from these tables, but they suggest a tendency of morphological variation of each species indicating a direction of develop- ment and even a trend of phylogenetic development of the bioseries in the way of domination and increase in the secondary spirals. Vol. 21; No. 2 IV. Turritella (Haustator) tricarinata — communis Bioseries M. Gicnoux (1913) first pointed out the phylogenetic rela- tionship between each form of the bioseries in the upper Cenozoic strata of the Mediterranean region, and HARMER (1914-1919) noted that each form belonging to this bioseries has a zonal significance in the British sequence. Then BaDEN-POWELL (1954) applied the phylogenetic develop- ment of the bioseries to the British sequence and made an attempt to correlate the Pliocene and Pleistocene deposits between Britain and the Mediterranean region. As shown in Figure 7, the bioseries of the Mediterranean and British forms are represented by the domination and strengthening of the secondary spirals. According to BADEN-POWELL (1955: 278), the develop- ment in sculpture of this bioseries can be described in the following way: “Not only does the size of the shell increase from T. trica- rinata to T. communis, but also the ornament of three spiral ridges seen in T. tricarinata acquires subordinate interme- diate ribs in T. communis until they are as strong as the original primary ribs and make seven or more ribs of equal size. Gignoux also noted that the tricarinata and pliorecens forms of ornament can be recognized on the early whor! of the modern individuals of T. communis:’ BonpI & SANDRUCCI's (1949) statistical analysis on the fos- sil community of Turritella (Neohaustator) pliorecens Monterosato (— tricarinata of Bondi and Sandrucci, 1949, non. auct.) collected from the Calabrian deposits of Italy also suggests the phylogenetic trend of the bioseries from T. tricarinata to T. communis through T. pliorecens; their Statistics are given in Table 4. Table 4 Variation of the surface sculpture of Turnitella (Haustator) pliorecens Monterosata from the Calabrian deposits of Italy. (after Bonp1 & SaNpRuccI, 1949) Class Number of Specimens 3 8 4 10 5 46 6 132 7 139 8 156 9 95 10 35 11 16 12 14 THE VELIGER Page 193 In Table 4, the class represents the number of the whor! on which the first intercalary spirals or secondary spirals begin to appear, that is, according to Bondi and Sandrucci, the specimens included in the first three classes are allo- cated to the typical Turritella communis, and these of the last three to the typical T. tricarinata. Although they lumped up these forms into one species of T. tricarinata, and considered them to be of varieties because of their con- tinuous change in sculpture, the writer believes that this community from the Calabrian should be allocated to the species of T. pliorecens according to the mode given by the frequency of morphological variations in the community, thus, the phylogenetic trend of the bioseries can be easily recognized from the viewpoint of population structure. CONCLUDING REMARKS All of these phylogenetic series or bioseries described above are exhibited by progressive increases in density and strength of secondary and tertiary spiral sculpture. This analogy seems to be a phenomenon of parallel evolution taking place contemporaneously in each regional or local bioseries. And further, sudden and considerable change in sculp- ture in each bioseries is detected across the Pliocene-Pleis- tocene boundary shown as a broken line in Figure 3. a JAPAN NEW ZEALAND CALIFORNIA HOLOCENE 4 . p.communia andenensis otukaz d.vellat (UEC BrArr,) PLEISTOCENE t pliorecens ; k (ucts. s.Ar.) f s (uC BA r) ec. semen aan PLIOCENE a.motidukii MS Ly) margaritana (Ci. A) carrisaensis (Cc A) ¢.paucteculpta (C b A) satehuensis(s.s) kaawaensis tricarinata ¥ (C Bs A) ane Cy. BA x) Q 8 6 MIOCENE moodyt ( ) Figure 3 Correlation table of 4 turritellid bioseries Page 194 THE VELIGER Vol. 21; No. 2 At the present, although the physiological significance and mechanism of development in spiral ornamentations are not yet fully known, it can be emphasized that the world-wide decline of marine water temperature and/or shallowing of the marine realm caused by world-wide sea level change are reflected by sudden changes in sculpture, and this boundary roughly corresponds to the Neogene- Quaternary boundary when the world-wide ice-sheets started to develop. In Italy, this boundary can be drawn between the Astian and Calabrian stages, that is, at the generally accepted Neogene-Quaternary boundary. In the New Zealand bio- series, this boundary corresponds to that of the Waitotaran and Nukumaruan Stages. And HorniBrook (1977) in sum- marizing the age determination of the New Zealand stages, put the Neogene-Quaternary boundary at the top of the Mangapanian Stage or the Waititaran Stage of old sense mainly by means of planktic foraminiferal ranges. His Neogene-Quaternary boundary is quite safely assigned to the boundary between the Stiracolpus kaawaensis and S. delli vellai zones in the stratotype sequence of the Waito- taran and Mukumaruan Stages along Wanganui Beach of North Island, New Zealand. But placement of the Neogene-Quaternary boundary in Japan is still controversial; for example, IkEBE et al. (1977) ~ \ A Ws } A Q T. saishuensis BIOSERIES Lis put this boundary at the base of the Kitaura Formation correlative of the Tentokuji Formation in Figure 2, mainly based on a magnetostratigraphic event and the last occur- rence of the planktic foraminifer Globoquadrina asanoi. At the same time, they noted that discrepancies still exist in age and correlation, especially with the scheme of mol- luscan biostratigraphers. According to AppicoTt (1977), the Neogene-Quaternary boundary in California has not been drawn strictly, but it seems to the writer that the boundary in question can still be drawn on at the base of the San Pedro Formation includ- ing the Timms Point Siltstone Member of recent sense as already shown by Merriam’s text-figure (1941: 49, fig. 8) cited above. ACKNOWLEDGMENT . The writer would express his appreciation to Dr. Warren O. Addicott of the United States Geological Survey, Menlo Park, California for his critical reading of the manuscript, and giving the writer the chance to study the specimens of Turritella coopert of California from the United States Geological Survey collections, Menlo Park, California. ert BIOSERIES Z. kaawaensis BIOSERIES Figure 4 Bioseries of the Pacific and the Mediterranean turritellids Vol. 21; No. 2 THE VELIGER Page 195 FORMATION | TENTOKUJI SASAOKA SHIBIKAWA Rae A 7 T.otukat Zone T.andenensia Zone g.motidukit Subzone|gaishuensis(s.s.)Subzone s.etigoensia a, taushimaensts SPECIES andenensis a. motidukit saishuensis (s.s.) (.u.C.t.B.s.A.r) 8. ettgoensis (C B A) (C Bs A) (..C...B.s.A.r) andenensia (.u.€.t.B.s.a.r.) Figure 5 Phylogeny of Turritella (Neohaustator) saishuensis — andenensis Bioseries in Japan NUKUMARUAN CASTLECLIFFIAN HAVIERAN RECENT OPOITIAN WATTOTARAN u. ruahinensis (.u.c.t.b.s.a.r) d. grant SPECIES (.u.C.t.B.s.A.r Tr) Uitte: ut t kaauaensis Ce (.u.C.t.B.s.a.r. (uC BA r) Eetso)) ‘ae + A d. vellai d. murdochi (uc tBsAr) (uct Rsar) f- Figure 6 Phylogeny of Zeacolpus (Stiracolpus) kaawaensis — delli Bioseries in New Zealand Page 196 THE VELIGER Vol. 21; No. 2 PosT- STAGE ASTIAN CALABRIAN SICILIAN SPECIES |- 4 A communis pltiorecens tricarinata (uc tbsar) (uctB. (uc. BAr) Figure 7 Phylogeny of Turritella (Haustator) tricarinata — communis Bioseries in Italy Literature Cited AppicoTT, WARREN OLIVER 1977. Neogene chronostratigraphy of nearshore marine basins of the eastern North Pacific. Proc. 1st Internat. Congr. Pacif. Neogene Stratigr., Tokyo, Japan, 1976: 151-175; 4 text figs. ALLISON, RicHarD Casz & OLUWAFEYISOLA SYLVESTER ADEGOKE 1969. The Turritella rina group (Gastropoda) and its relationship to Torcula Gray. Journ. Paleont. 43 (5): 147-148; 2 text figs. Bapven-PoweE tt, D. F. W. 1955. The correlation of the Pliocene and Pleistocene marine beds of Britain and the Mediterranean. Proc. Geol. Assoc. 66 (4): 271 - 292; 1 text fig. Bono, F. « L. SaNpRucci 1949. Su alcuni Molluschi plioceniti della Val d’Ere (Toscana) e su alcune anomalie de sviluppo. Atti Soc. Toscana Sci. Nat. Mus., Ser. A, 56: 1-17; 1 table Bow es, Epcar 1939. Eocene and Paleocene Turritellidae of the Atlanticand Gulf coast- al plain of North America. Journ. Paleont. 13 (3): 267 - 336; 4 pits. Guituaume, Louis 1925 (for 1924). Essai sur la classification des turritelles, ainsi que sur leur évolution et leurs migrations, depuis le début des temps tertiaires. Bull. Geol. Soc. France (4) 24: 281 - 311 Hornisroox, Norcotr ve B. 1977. The Neogene (Miocene-Pliocene) of New Zealand. Proc, 13t Internat. Congr. Pacif. Neogene Stratigr. Tokyo, Japan 1976: 145 - 150; 2 text figs. Ipa, KazuyosHtr 1952. A study of fossil Turritella of Japan. Rept. Geol. Surv. Japan, no. 150: 1-64; 7 plts.; 25 text figs.; 4 tables IxEBE, Nosuvo 1940. On the stratigraphy of the Hatikoku and Oziya oil fields, Niigata Prefecture. Journ. Japan. Assoc. Petrol Technol. 8 (5): 333-344 (in Japanese) Ixese, N. e¢ al. 1977. Summary of bio- and chronostratigraphy of the Japanese Neo- gene. Proc. 1st Internat. Congr. Pacif. Neogene Stratigr., Tokyo, Japan, 1976: 93 - 113; 5 text figs.; 2 tables Koraxa, TAMIO 1954. Ontogeny and phylogeny of some species of the genus Turritella from Akita oil field. Seibutsu-Kagaku (Biol. Sci.), spec. vol., Evo- lution: 34 - 39; 4 text figs.; 2 tables (in Japanese) 1959. The Cenozoic Turritellidae of Japan. Sci. Rept. Tohoku Univ. (2) 31 (2): 1-135; 15 plts.; 10 text figs.; 7 charts; 3 tables 1960. Similarity in the turritellid phylogeny in the late Cenozoic. Sci. Rept. Tohoku Univ. (2) Special volume (4): 301 - 308; 4 text figs. Lesour, Marie V. 1933. The eggs and larvae of Turrttella communis and Aporrhais pes- pelicant. Journ. Mar. Biol. Assoc. U, K., n.s. 18 (2): 499; 2 plts. Marwick, JoHN 1957. New Zealand genera of Turritellidae, and the species of Stira- colpus. New Zeal. Geol. Surv., Paleont. Bull. 27: 1-55; 5 plts.; 5 text figs. 1971. Record of an ovoviviparous Zeacolpus. Geol. & Geophys. 14 (1): 66-70 MerriAM, Cares W. 1941. Fossil turritellas from the Pacific Coast region of North America. Univ. Calif. Publ:, Bull. Geol. Sci. 26 (1): 1-214; 41 plts.; 19 text figs.; 1 map (8 March 1941) Oruxka, YANOSUKE 1934. Tertiary structures of the northwestern end of the Kitakami Mountainland, Iwate Prefecture, Japan. Bull. Earthq. Res. Inst., Univ. Tokyo 12 (3): 566 - 638; plts. 44-51; 1 map PaLtmer, KATHERINE EVANGELINE HitToN VAN WINKLE 1958. Viviparous Turritella pilsbryi Gardner. (1): 210-213 New Zeal. Journ. Journ. Paleont. 92 1961. Additional note on ovoviviparous Turritella. Journ. Paleont. 35 (3): 633 Pete, A. J. 1922. Note on reproduction of Turritella. Proc. Malacol. Soc. London 15 (1): 13 Yokoyama, Matajiro 1923. On some fossil shells from the Island of Saishu in the Straits of Tsushima. Journ. Coil. Sci., Imp. Univ. Tokyo 49 (7): 1-9; 1 plt. Vol. 21; No. 2 THE VELIGER Page 197 Neogene Pectinidae of the Northern Pacific KOICHIRO MASUDA Department of Geology, Miyagi University of Education, Aoba, Sendai, Japan 980 (1 Text figure) INTRODUCTION IT Is WELL KNowN that the Neogene Pectinidae is one of the most important groups of mollusks for age determina- tion and correlation of Neogene strata because of their rather short geological range and also because they are the largest group of fossil marine mollusks. The long duration from spawning through the pelagic and sessile stages to the free swimming stage favors wide dispersal, colonization of new habitats and, consequently, speciation. Also, as the pectinid shells are usually rather well preserved even when the majority of the associated shells are represented as molds or casts, their collection and identification is facili- tated. Therefore, they are good tools for interregional cor- relation. Among the Neogene pectinids of the Northern Pacific region Patinopecten, Mizuhopecten, Yabepecten, Swifto- pecten, Fortipecten and Chlamys cosibensis (Yokoyama) are considered to be significant for interregional correla- tion between Eastern Asia and North America because they are known from the Japanese Islands, Sakhalin, Kam- chatka, Alaska and the West Coast of North America. Also, the genus Amussiopecten is considered to be one of the most interesting and significant pectinids particularly from the viewpoint of its world wide distribution. In the present article remarks on the above mentioned Neogene pectinids of the Northern Pacific are given and paleontological significances are also discussed. NOTES on PECTINIDS oF THE NORTHERN PACIFIC 1) Patinopecten and Mizuhopecten The genus Patinopecten is one of the most interesting Cenozoic pectinids of the eastern North Pacific, because it is abundant in species, shows a wide range of morpholog- ical characters and has a rather restricted geological range. Patinopecten was established by DALL (1898) as a section of the genus Pecten based upon Pecten caurinus Gould, a common Recent scallop of the eastern North Pacific. Thenceforth, Patinopecten has frequently been recorded from the Recent seas of the Northern Pacific and from the Tertiary and Quaternary deposits of western North Amer- ica, the Japanese Islands, Sakhalin, and Kamchatka, but not from elsewhere. From a study of the so-called Patino- pecten of Japan the writer (MAsupA, 1963) pointed out that all of the Japanese fossil and Recent species of the so- called Patinopecten differs from the true Patinopecten of North America and he proposed the new genus Mizuho- pecten for most of the species of the so-called Patinopecten of Japan, based upon Pecten yessoensis Jay, a common Recent scallop of Northern Japan. Also, according to the writer's study (Masupa, 19714), it became evident that among the species described from the West Coast of North America Pecten (Patinopecten) bakeri Hanna and Hertlein (1927), Patinopecten bakeri diazi Durham (1g50a) and Patinopecten marquerensis Durham (1950a) described from the Pliocene strata of Baja California, Mexico, should be removed from Patino- pecten and placed in the newly proposed genus Leopecten based upon Pecten (Patinopecten) baker: Hannaand Hert- lein. Moreover, it became evident that Patinopecten (Mi- zuhopecten) skonunensis MacNeil (1967) can not be re- ferred to Mizuhopecten; but Patinopecten n.sp. illustrated by Appicotr (1966) from the Montesano Formation in Washington was described by the writer as a new species of Mizuhopecten (MasuDaA, 19712). The typical Patinopecten is specifically abundant dur- ing the Tertiary Period in western North America but only one Recent species is known—P. caurinus (Gould) which occurs north of San Francisco Bay. Patinopecten has been usually considered as a cool water indicator of the West Coast of North America. MACNEIL (1967) stated that most molluscan stocks on the West Coast of North America have older representatives in the Japanese Islands. However, as the writer pointed out (Masupa, 1963, 19714), it is evident Page 198 THE VELIGER Vol. 21; No. 2 that the ancestral stock of Patinopecten is not a migrant from Asia but probably from the Mediterranean region. In Japan the genus Mizuhopecten, ranging from the Oligocene to the Recent, is very abundant specifically and individually. But there are only two species known in the Pleistocene and only one from the Recent seas of Northern Japan. It seems probable that the majority of the Patino- pecten species recorded from Sakhalin and Kamchatka should be referred to Mizuhopecten, and that Patinopec- ten may not be found in the western Pacific borderland. In general, the water temperature gradually lowered from the early to latest Neogene in the Circum Pacific (DuRHAM, 1950b, MasupaA, 1963a, 1973b, ApDDICOTT, 1969), and the decrease in number of Patinopecten or Mizuhopecten species besides other pectinids during the Tertiary to the Recent may coincide with the lowering of the water temperature. It seems that the decrease in the pectinids on both sides of the Northern Pacific with ad- vance of geological time may be explained by the changes of environmental conditions. 2) Yabepecten Yabepecten established by the writer (MasupA, 1963) based upon Pecten tokunaga: Yokoyama from the Pliocene Koshiba Formation in Kanagawa Prefecture, can be con- sidered to be potentially significant in interregional corre- lation because of its restricted geological range and wide geographical distribution. Masupa & ADDICOTT (1970) pointed out that Pecten (Amusium) condoni Hertlein from the Montesano Forma- tion of western Washington, is a Yabepecten and not an Amusium. This was the first record of Yabepecten in the Tertiary of eastern North Pacific. Yabepecten is restricted to early Pliocene formations of Northern Japan. Judging from the associated fauna, the early Pliocene formations of Northern Japan were deposited under cool water condi- tions. And, from the fauna associated with Y. condoni in the Montesano Formation, a probable early Pliocene age is suggested. Owing to its geological record and its wide geographical distribution, it is of considerable significance in Circum North Pacific faunal correlation. It is expected that Yabepecten will be found from Sakhalin, Kamchatka, Alaska and other areas along the Eastern Pacific. 3) Swiftopecten and Nanaochlamys In 1935 HERTLEIN proposed Swiftopecten for Pecten swiftii Bernardi, a common Recent scallop of Northern Japan. Also Nanaochlamys was established by Hatar & MasupA (1953) based upon Pecten notoensis Yokoyama from the Miocene Nanao Formation, Ishikawa Prefecture, Japan. As known at present the oldest occurrence of Swiftopec- ten swifttt (Bernardi) is the middle Miocene formations of Northern Japan, where it is rather rare (MasupA, 195 9a). The associated molluscan fauna mainly comprises temper- ate water elements. But with the progress of geological age S. swiftit gradually increased its dominancy with the in- crease of cooler water mollusks from the middle Miocene through Pliocene to Recent (MAsupaA, 1959a, 1972). As pointed out by the writer (Masupa, 1960), Swiftopec- ten swiftit branched off from Nanaochlamys notoensis (Yo- koyama) in the middle Miocene. The morphological characters of N. notoensis, N. notoensis otutumiensis and S. swiftii closely resemble each other in their younger stage, but with growth the surface sculpture in the adult stage becomes considerably different. The surface sculpture in the younger stage of N. notoensis is retained in the adult stage of N. otutumiensis and S. swiftit, but the surface sculpture in adult stage of N. notoensis is not observed in that of the latter. And, N. otutumiensis and S. swiftii occur from a geological horizon higher than that of N. notoensis. Therefore, it is inferred that N. notoensis is ancestral to N. otutumiensis and S. swiftit, that is to say, N. otutumien- sis and S. swiftii branched off from N. notoensis in the middle Miocene and they represent parallel forms of ge- neric distinction. During the early Miocene N. notoensis Was a warm water inhabitant as shown from the associated fauna. But it became extinct probably owing to the diverse environmental conditions at the end of the early Miocene. Nanaochlamys otutumiensis and S. swiftii branched off from N. notoensis in the late early Miocene. Nanaochlamys otutumiensis became extinct by the influence of rather cool water conditions of the late Miocene, but S. swiftii sur- vived to the Recent with little morphological variations. Consequently, the factors controlling the evolutionary change in the N. notoensis group were probably due in part to the difference of environmental conditions. Nana- ochlamys notoensis and N. notoensis otutumiensis are not known from Sakhalin, Kamchatka and Alaska. The first appearance of Swiftopecten along the West Coast of North America is in the Yakataga Formation in Alaska, which yielded S. donmilleri (MacNEI, 1967; KANNO, 1971). It is thought that the occurrence of Swifto- pecten along the West Coast of North America is a result of its migration from Asia to North America. Therefore, the writer considers that the Yakataga Formation in Alaska isat least not older than the middle Miocene formationsin Japan. Swiftopecten swiftii extended its distribution to Northern California in the early Pliocene and S. swiftii parmeleei (Dall) which is known from Central to Southern Vol. 21; No. 2 THE VELIGER Page 199 California, branched off from the S. swiftit stock as a result of its southward migration followed by localization and adaptation in the middle Pliocene and it became extinct at the end of middle Pliocene. On the other hand, with prog- ress of geological age S. swiftii retreated to Alaska and be- came extinct in the Pleistocene. Therefore, it is expected that S. swiftii will be found from the Pliocene and Pleisto- cene formations of the northern part of western North America (MAsuDaA, 1972). As already stated by the writer (MAsupDA, 1959a), some morphological differences such as concentric constrictions or the nature of the radial ribs of the left valve in Swifto- pecten swiftit are observed between specimens living in the northern areas and those living in more southern areas. These morphological features suggest that the specimens living in the northern areas are somewhat less influenced by the water temperature than those living in more south- ern areas. And, the morphological differences observed between the fossil and Recent specimens may be the reflec- tion of the environmental conditions such as water tem- perature. From such inferences it may be interpreted that the so-called S. kindle: represents the northern type of S. swiftit and that some of the so-called S. parmeleei from northern California represent the southern type of S. swifti. Also, the so-called S. donmilleri may represent the southern type of S. swifti. Therefore, it can be considered that the Yakataga Formation that yielded S. swifti: may have been deposited under the influence of temperate to cool water environmental conditions. Although the geo- logical age of the Yakataga Formation is now open to ques- tion, the writer is inclined to consider that a part of the Yakataga Formation may represent the late Miocene or very early Pliocene. 4) Fortipecten Since YOKOYAMA (1930) described Pecten takahashi from the Pliocene Maruyama Formation in South Sakha- lin, the species was frequently recorded from the Pliocene formations in Japanese Islands and Sakhalin. In 1940 YABE & Hatatr established the genus Fortipecten based upon P. takahashii Yokoyama. The genus Fortipecten has hitherto been considered to be an important Pliocene pectinid of Northern Japan, until Kotaka &« Nopa (1967) described F. kuroishiensis from the middle Miocene Ogawara Formation, Aomori Prefecture, Northern Honshu, Japan. Among three spe- cies of Fortipecten, F. takahashii, F. kenyoshiensis and F. kuroishiensis, known from the Japanese Islands, F. taka- hashii is the most important species, particularly from the viewpoint of its restricted geological range and very wide geographical distribution from middle Northern Honshu northward to Hokkaido and Sakhalin and Kamchatka (Masupa, 1962b). On the other hand, several species such as Fortipecten takahashit, F. pilutunensis, F. sachalinensis, and F. miro- novi, have been described from North Sakhalin and Kam- chatka (KHOMENKO, 1931; SLODKEWITSCH, 1938; ILYNa, 1963; KRISHTOFOVICH, 1964). And F. hallae (Dall) (Mac- NEIL, 1943) and F. mollerensis MacNeil (1967) have been described from Alaska. Therefore, the occurrence of Forti- pecten in the Circum North Pacific is a result of migration from the Japanese Islands. However, those mentioned spe- cies are in need of further study to clarify their taxonomic relations. For example, according to the present writer’s study based upon the holotype and topotype of F. moller- ensis MacNeil, it is evident that MacNeil’s mollerensis is different from Fortipecten and should be referred to Mizu- hopecten. 5) Chlamys costbensis (Yokoyama) Chlamys cosibensts was first described by YOKOYAMA (1911) from the Pliocene Koshiba Formation, Kanagawa Prefecture. Thenceforth, this species has been frequently recorded from the Miocene to Pliocene formations of Japan and its adjacent areas. The first occurrence of Chlamys cosibensis (Yokoyama) is in the middle Miocene of Northern Japan and at that locality the associated molluscan fauna consists mainly of temperate water elements. The ancestral form of C. cosi- bensis (s. s.) is considered to be C. cosibensis hanzawae Masuda (1959b) which is known from the early Miocene formations of Japan, where it occurs in association with warm water mollusks. With the progress of geological age C. cosibensis (s. s.) increased its dominancy in association with an increase of cooler water mollusks from the middle Miocene to early Pliocene. Chlamys cosibensis (s. s.) has been frequently recorded from the early Pliocene forma- tions of the Japan Sea borderland and the K wanto region (MasupA, 1962b). It has been recorded from North Sakha- lin and Kamchatka (SLODKEWITsCcH, 1938; ILYNA, 1963; KRISHTOFOVICH, 1964, 1969). Also, as pointed out by the writer (MasupDA, 1973a) MacNeil’s C. (Swiftopecten) leo- hertleint from the Pliocene Tachilni Formation at the western end of the Alaska Peninsula (MACNEIL, 1970) is a synonym of C. cosibensis (s. s.). Moreover, MACNEIL (1973) illustrated C. (Swiftopecten) donmilleri MacNeil from the Unga Conglomerate Member of Bear Lake For- mation, Alaska Peninsula, but according to the writer's study of the specimens preserved in the collections of the California Academy of Sciences, San Francisco and Re- Page 200 Pacific THE VELIGER Vol. 21; No. 2 Ocean Figure 1 Geographical Distribution of Chlamys cosibensis (Yokoyama) search Center of Amoco Production Company, Tulsa, from the same locality as MacNeil'’s C. donmillert, it is evident that MacNeil’s C. donmiller: is a synonym of C. cosibensis (s. s.). because the morphological characters are quite similar with those of C. cosibensis (s. s.). The geo- graphical distribution of C. cosibensis (Yokoyama) 1s shown in Text figure 1. The writer pointed out (Masupa. 1973a) that the size of Chlamys cosibensis (s. s.) from middle Miocene formations is usually smaller than those from Pliocene formations and also that the radial ribs of the Miocene specimens are gen- erally somewhat more distinct and somewhat higher than those of the Pliocene forms. Therefore, based upon mor- phological characters the geological age of the C. cosiben- sis (5. s.) bearing formations can be determined, and corre- lation of the geographically isolated formations can be undertaken. Since C. cosibensis (s. s.) from Alaska (MAc- NEIL, 1970, 1973; MasuDA, 1973a), Sakhalin (ILyNa, 1963) and Kamchatka (SLoDKEWITSCH, 1938, KRISHTOFOVICH, 1969; MasupaA, 1973a) are of the Pliocene type of mor- phology, the writer considers that their occurrence is a result of migration from the Japanese Islands via Kam- chatka to Alaska during the early Pliocene, although Mac- NEIL (1973) assigned the Unga Conglomerate Member of Bear Lake Formation in Alaska Peninsula to the early Middle Miocene. 6) Amussiopecten Amussiopecten has been frequently recorded from var- ious localities in Neogene and Paleogene formations in South and Central Europe, the Mediterranean Region, Iran, East Africa, Madagascar, South East Asia and East Asia, but no species has been described and recorded under Amussiopecten from either North America or South Amer- ica. But according to the writer's study (Masupa, 1971b) it became evident that several species from the Oligocene and Miocene formations along the West Coast of North America, Central America, the Caribbean Region and northern South America, should be referred to the genus Amussiopecten. And all species of Amusstopecten in Eu- rope, Africa and America became extinct at the end of the middle Miocene, but three species of Amusstopecten in East Asia survived to the Pliocene. In general, the decrease in number of species with time can be explained by the changes in oceanographic envi- ronmental conditions. Therefore, as the result of these changes all species of Amusstopecten in Europe, Africa and America became extinct at the end of middle Miocene but in East Asia three species were able to survive to the early Pliocene. That is to say, the environmental conditions in East Asia have been more stable than those of the other areas from the early Miocene to the early Pliocene. From the accounts given above it appears that the distribution of Amussiopecten has been dependent upon progressive changes in oceanographic conditions during its geological range. Therefore, world wide occurrences of Amusstopec- ten are considered to be very significant for interregional correlation. The late Oligocene to Middle Miocene pectinids in North America are usually composed of European ele- ments, but the Late Miocene to Pliocene pectinid fauna of the northern West Coast of North America generally con- tains a mixture of Asian elements, the survivors of Miocene Vol. 21; No. 2 pectinids and endemic genera. But along the southern West Coast of North America, the East Coast of North America and in the West Indies, the pectinid faunas differ greatly from those of the northern West Coast since the late Miocene. Along the southern West Coast the Pliocene pectinid fauna reveals a quite different aspect from those of northern part. These faunal provinces indicate geo- graphic differentiation. CONCLUDING REMARKS The occurrences of the Japanese pectinids such as Mzzo- hopecten, Yabepecten, Swiftopecten, Fortipecten, Amus- siopecten and Chlamys cosibensis in the Neogene forma- tions of the northern part of the West Coast of North America are significant for Circum Pacific correlation of the Neogene formations. In general, there are two periods of remarkable develop- ment of the Pectinidae in the Tertiary of Japan (Masupa, 1962b). These two periods mark the abrupt appearance of genera and subgenera, extreme individual variability and species differentiation. The two unstable periods are rep- resented by the early Miocene and early Pliocene ages (Masupa, 1962b; 1973b). Such remarkable features are also recognized in the Pectinidae of the ‘Vaqueros’ and “‘Jacalitos” stages of the West Coast of North America (ARNOLD, 1906; AppicoTT, 1974), and also in the Japanese Turritellidae (KOTAKA, 1959), Arcidae (NopA, 1966) and others. The Miocene Pectinidae of Japan can be classified into early, middle and late Miocene (Masupa, 1962b). As stated earlier, during the early Miocene, the Pectinidae were abundant in species and individuals, showed a wide variety of sculpture and possessed a rather restricted chronological distribution. The early Miocene Pectinidae of Japan had a rather wide geographical distribution and was represented by the Nanaochlamys notoensis assemblage zone. In the middle Miocene the pectinid fauna became more varied, being represented in Northern Japan by the shallow water Miyagipecten matsumoriensis assemblage and the Mizu- hopecten kimurai assemblage. In Southern Japan the pec- tinid fauna is represented by the Amusstopecten aktyamae assemblage, whereas in Central Japan there is a mixed pec- tinid assemblage consisting of the elements of Southern Japan and Northern Japan. Although the late Miocene pectinids are characterized by the mixed assemblage of the survivors of the earlier horizons and the appearance of some Pliocene species, their detailed characters are not well known, because of the restricted distribution of the pectinid-bearing formations. THE VELIGER Page 201 Another development of the Pectinidae is recognized at the beginning of the Pliocene age in Japanese Islands. The early Pliocene is characterized by the Yabepecten tokuna- gai assemblage in the Japan Sea borderland and K wanto region, the Fortipecten takahashii assemblage in the North- ern Pacific borderland and the Amussiopecten praesignis assemblage in the Southern Pacific borderland. Among the early Pliocene pectinid assemblages, the F. takahashii as- semblage can be traced from Northern Japan through Sakhalin to Kamchatka and the Y. tokunagai assemblage from Japan to the Alaska Peninsula. The A. praesignis assemblage can be traced from Central Japan to Taiwan and tends to change northwards gradually to the Y. toku- nagai assemblage. The Y. tokunagai and F. takahashii as- semblages may have been controlled within the same sedi- mentary province by ecological and other conditions. Consequently, it is reasonable to correlate the early Plio- cene formations of the Japanese Islands with the Pomyr Series in North Sakhalin, the Upper Kavran and Etron- skaja Series in Kamchatka, the Tachilni Formation and Unga Conglomerate in Alaska, and also with the Monte- sano Formation in Washington. The mentioned correla- tion of the Pliocene formations in the Northern Pacific area is also supported by the other molluscan faunas. ACKNOWLEDGMENTS Acknowledgments are due to the late Dr. Kotara Hatai, Professor Emeritus of Tohoku University, Dr. A. Myra Keen, Professor Emeritus, Department of Geology, Stan- ford University, Dr. J. Wyatt Durham, Professor Emeri- tus, Museum of Paleontology, University of California in Berkeley, and Dr. David M. Hopkins, U.S. Geological Survey, Menlo Park, for their encouragement. The writer expresses his deep gratitude to Dr. Warren O. Addicott of the U. S. Geological Survey, Menlo Park, who helped him in various ways. Literature Cited Appicotr, WARREN OLIVER 1966. New Tertiary marine mollusks from Oregon and Washington. Journ. Paleont. 40 (3): 635-646; plts. 76-78; 1 text fig. 1969. Tertiary climatic change in the marginal northeastern Pacific Ocean. Science 165: 583 - 586; 3 text figs. 1970. Latitudinal gradients in Tertiary molluscan faunas of the Pa- cific Coast. Paleogeogr., Paleoclimat., Paleoecol. 8: 287-312; 7 text figs. 1974. | Giant pectinids of the eastern North Pacific margin: signifi- cance in Neogene zoogeography and chronostratigraphy. Journ. Paleon. 48 (1): 180-194; 2 plits.; 7 text figs. ARNOLD, RALPH 1906. ‘Tertiary and Quaternary Pectens of California. Surv. Prof. Paper 47: 7-146; 53 plts.; 2 text figs. U. S. Geol. Page 202 THE VELIGER Vol. 21; No. 2 Asano, Kryosui « Kotora Hatai F 1967. Micro- and macropaleontological Tertiary correlations within Japanese Islands and with planktonic foraminiferal sequences of for- eign countries. In K. Harat (ed.): Tertiary correlation and cli- matic changes in the Pacific. 11th Pacif. Sci. Congr. Symp. 25, Tokyo: 77-87 Dari, Witiiam HEALEY 1898. Contributions to the Tertiary fauna of Florida, with special ref- erence to the Silex beds of Tampa and the Pliocene beds of the Caloosa- hatchie River, including in many cases a complete revision of the gen- eric groups tented and of their American Tertiary species. Part IV. 1. Prionodesmacea: Nucula to Julia. 2. Teleodesmacea: Teredo to Ervilia. Trans. Wagner Free Inst. Sci. Phila. 3 (4): 571-947; pits. 26-37 (October 1898) 1920. Pliocene and Pleistocene fossils from the Arctic coast of Alaska and the auriferous beaches of Nome, Norton Sound, Alaska. U.S. Geol. Surv. Prof. Paper 125-C: 23 - 37; plts. 4, 5 (27 January 1920) Duruam, JoHN WyatTr 1950a. Megascopic paleontology and marine stratigraphy. In: S. A. ANDERSON, J. W. Duruam, F. P Sueparp, M. L. NaTtLanp & R. REveELLE 1940 E. W. Scripps Cruise to the Gulf of California, Part IT. Geol. Soc. Amer. Mem. 43: 1 - 216; 48 plts.; 3 text figs. 1950b. Cenozoic marine climates of the Pacific coast. Amer. Bull. 61: 1243 - 1264; 3 text figs. Grant, Utysszs Simpson, IV « Hoyt Ropney Gare 1931. Catalogue of the marine Pliocene and Pleistocene Mollusca of California and adjacent regions. Mem. San Diego Soc. Nat. Hist. I: 1- 1036; 32 plts.; 15 text figs. (3 November 1961) Hanna, G Datias «& Lzo Gzorce HERTLEIN 1927. Expedition of the California Academy of Sciences in the Gulf of California in 1921: Geology and Paleontology. Proc. Calif; Acad. Sci. (4) 16 (6): 137-1573 1 plt. Hatat, Kotora & Ké1cuir6 Masupa 1953. On the Pecten notoensts Yokoyama (On the Miocene Pectinidae from the environs of Sendai, Part 2). Palaeont. Soc. Japan Trans. Proc. n. s. 11: 75-82; 1 plt.; 3 text figs. HerTLEIN, Leo GeorGE 1925. New species of marine fossil Mollusca from western North A- merica. South. Calif. Acad. Sci. Bull. 24 (2): 39-46; plts. 3, 4 Ityina, AcrtvA PETROVNA 1963. | Mollusks in the Neogene of Kamchatka. Soviet Petrol. Sci. Res. Geol. Inst. Trans. 202: 1 - 242; 54 plts. (in Russian) Kanno, Saburo 1971. ‘Tertiary molluscan fauna from the Yakataga District and ad- jacent areas of southern Alaska. Palaeon. Soc. Japan, Spec. Paper no. 16: 1- 154; 18 plts.; 20 text figs.; 7 tables Kuomenxo, J. 1931. Materials on the stratigraphy of the Tertiary beds of the eastern Sakhalin oilfield. Geol. Prospect. Serv. U.S.S.R. Trans. 79: 1-126; 12 pits. KorTaxa, TAMIO 1959. The Cenozoic Turritellidae of Japan. Sci. Rept. Tohoku Univ. (2) (Geol.) 31 (2): 1-135; 15 plts.; 10 text figs. Kortaxa, Tamio « Hrrosu1 Nopa 1967. | Miocene Mollusca from the Minami-Tsugaru district, Aomori Prefecture, Northeast Japan. Saito Ho-on Kai Mus. Res. Bull. 36: 33 - 47; 2 plts. KrisutorovicH, LummMILta VYACHESLAVONA 1964. Mollusks from the Tertiary sediments of Sakhalin. Soviet Petro]. Geol. Exped. Inst. Trans. VNIGRI 292: 1-344; 55 plts.; 3 text figs. (in Russian) 1969. Molluscan study in the eastern Kamchatka. Soviet Petrol. Geol. Exped. Inst. Trans. VNIGRI 268: 228 - 238; 3 plts. (in Russian) Geol. Soc. MacNet, Francis STEARNS 1967. Cenozoic pectinids of Alaska, Iceland, and other northern re- gions U.S. Geol. Surv. Prof: Paper 553: 1 - 533 25 pits. 1970. New Pliocene Chlamys (Swiftopecten) and Beringius from the Alaska Peninsula. The Nautilus 84 (2): 69-74; 5 text figs. 1973. Marine fossils from the Unga Conglomerate Member of the Bear Lake Formation, Cape Aliaskin, Alaska Peninsula, Alaska. Sci, Rept. Tohoku Univ., Sendai (2) (Hatai Memorial Vol.) 6: 117-123; 2 pits. MacNetz, Francis STEARNS, JoHN B. Mertiz & HENRY Aucustus Pitsspry 1943. Marine invertebrate faunas of the buried beaches near Nome, Alaska. Journ. Paleont. 17 (1): 69-96; plts. 10-16 Masupa, KéicHIrR6 19592. On the Miocene Pectinidae from the environs of Sendai; Part 14. On Pecten swiftit Bernardi. Palaeont. Soc. Japan Trans. Proc., N. S. 34: 86-96; 1 pit.; 1 text fig. 1959b. On the Miocene Pectinidae from the environs of Sendai. Part 15. Pecten cosibensis Yokoyama and its related species. Palaeont. Soc. Japan Trans. Proc. N. S. 35: 121-132; 1 plt.; 1 text fig. 1960. On morphogenesis of Nanaochlamys. Sci. Rept. Tohoku Univ. 2nd Ser. (Geol) Spec. vol. (Hanzawa Mem. vol.) 4: 371 - 383; 1 plt.; 10 text figs. 1962a. ‘Tertiary Pectinidae of Japan. Sci. Rept. Tohoku Univ. and Ser. (Geol.) 33 (2): 117-238; plts. 18-27; 11 text figs. 1962b. Notes on the Tertiary Pectinidae of Japan. Sci. Rept. Toho- ku Univ. 2nd Ser. (Geol.) Spec. vol. (Kon’no Mem. vol.) 5: 159 - 193; 9 text figs. 1963. The so-called Patinopecten of Japan. Trans. Proc. n. s. 52: 145-153; plts. 22, 23 1971a. On some Patinopecten from North America. Palaeont. Soc. Japan Trans. Proc. 83: 166-178; plts. 19-21; 2 text figs. 1971b. Amussiopecten from North America and northern South A- merica. Palaeont. Soc. Japan Trans. Proc. 84: 205 - 224; plts. 25, 26; 4 text figs. 1972. Swiftopecten of the northern Pacific. Trans. Proc. 87: 395 - 408; plts. 48, 49; 1 text fig. 1973a. Chlamys cosibensts (Yokoyama) of the northern Pacific. Sci. Rept. Tohoku Univ. 2d Ser. (Geol.) Spec. vol. (Hatai Mem. vol.) 6: 109-116; plts. 8, 9; 1 text fig. 1973b. Molluscan biostratigraphy of the Japanese Neogene. Mem. Geol. Soc. Japan 8: 107 - 120; 2 plts.; 1 text fig. (J, E) Masupa, Kéicuir6 & WARREN OLiver AppICoTT 1970. On Pecten (Amusitum) condoni Hertlein from the west coast of North America. The Veliger 18 (2): 153-156; 1 pit. (1 October 1970) Palaeont. Soc. Japan Palaeont. Soc. Japan Masupa, Kéicuié « Hmosui Nopa 1976. | Oheck-list and bibliography of the Tertiary and Quaternary molluscs of Japan, 1950-1974. Saito Ho-on Kai: 1-494; 4 text figs. Nopa, HirosHr 1966. The Cenozoic Arcidae of Japan. (2) 38 (1); 1-161; 14 plts. SLopKeEwItTscH, W. S. 1938. Tertiary pelecypods from the Far East. Prts. 1 & 2. U.S.S, R. Acad. Sci. Palaeont. Inst., Palaeontology of U. S. S. R.; ro prts. 3 (19): 1-275; 106 plts. Yase, Hisakatsu & Kotora Hatat 1940. A note on Pecten (Fortipecten, subgen. nov.) takahashii Yoko- yama and its bearing on the Neogene deposits of Japan. Sci. Rept. Tohoku Imp. Univ. 224 Ser. (Geol.) 21 (2): 147-160; plts. 34, 35 Yokoyama, MATAJIRO IQIt. Pectens from the Koshiba Neogene. 18 (208): 1-5; 1 plt. 1930. ‘Tertiary molluscs from South Karafuto. Journ. Fac. Sci. Imp. Univ. Tokyo Sec. 2, 2 (10): 407 - 418; plts. 70-80 Sci. Rept. Tohoku Univ. Journ, Geol. Soc. Tokyo Vol. 21; No. 2 Page 203 Neptunea (Gastropoda : Buccinacea) in the Neogene of the North Pacific and Adjacent Bering Sea CLIFFORD M. NELSON U. S. Geological Survey, Reston, Virginia 22092 (2 Plates; 9 Text figures) INTRODUCTION THE FRIGIOPHILIC, large gastropod Neptunea Roding, 1798, ex Bolten MS, a scavenger and facultative predator, Is a Conspicuous, common element in arcto-boreal, inshore benthic faunas of the late Cenzoic in the Northern Hemi- sphere. Gouikov (1963) and NELSson (1974) revised the taxonomy of living and fossil Neptunea, and established it as a more modern genus than portrayed previously. Nep- tunea, indigenous to the western North Pacific, evolved in waters off northern Japan and Sakhalin during the early Oligocene. It is distributed widely in post-early Miocene, outer sublittoral to upper bathyal molluscan faunas north of 32° N in the North Pacific and adjacent Bering Sea. Al- though entirely epifaunal crawlers after hatching, the spa- tial distribution of Neptunea mirrors those of Fusitriton and Mya which have pelagic larvae. Its distinctiveness, abundance, taxonomic diversity, widespread geographic distribution, and relatively rapid evolution make Neptu- nea a key element in the biochronology of upper Cenozoic strata in the boreal North Pacific. Distinctive spiral sculp- ture on early adult whorls of Neptunea distinguishes three subgenera, and four stocks within N. (Neptunea), each of which displays a distinctive phyletic and zoogeographic pattern. Neptunea (Golikovia) and N. (Neptunea) were distinct taxonomically by the late Oligocene. Neptunea (Sulcosipho) evolved from, or shares a common ancestry with, N. (Neptunea) in the late Oligocene or earliest Miocene. GENERAL MORPHOLOGY Neptunea (Neptunea) antiqua (Linnaeus, 1758), the type species from the eastern North Atlantic (NELSON, 1976), exhibits the basic shell form of the genus (GoLikov, 1963: pit. XXIII, fig. 1a; PEARCE & THORSON, 1967: text figs. 1-3; NELSON, 1974: plt. 53, figs. 1, 3). Species of Neptunea have shortened to moderately elongate fusiform, dextrally- coiled, adult shells of 50 to 200 mm or more in length. Sin- istral shelis are rare. Well-developed spiral sculpture, often of three or four orders of strength, typifies Neptunea. Ontogenetic changes involve differentia! development of subordinate spiral ele- ments. These shells lack alternation of spiral, axial, or re-- ticulate sculpture. Descriptive Notation of Spiral Sculpture In a descriptive notation modified from that used for turri- tellids by MERRIAM (1941), KOTAKA (1959), and ALLISON (1965), the primary spiral rib (first order of strength) at the shoulder of the initial adult (or teleoconch) whorl is de- noted “‘B:’ Visible spirals anterior (abapical) to “B’” on that whorl are in succession ‘C;’ “D;’ “E,’ e¢ seq. Equivalent lower case letters denote reduced development of these ribs. Letters enclosed by parentheses indicate that these spiral elements may be absent in some specimens of the taxon. “‘A”’ or ‘‘a’’ designates the primary spiral rib on the Page 204 subsutural shelf or ramp. Unlike turritellids. no primary ribs originate anteriorly to ‘“B” on the younger whorls of the adult shell. Subscript numerals indicate the whorl on which the spiral elements originate. Axial sculpture (lobes, lamellae, and varices, but never ribs) is absent or rare. and when present 1s confined usually to posterior (adapical) whorls. Subgenus-Group Taxa Despite the highly developed polymorphism within Nep- tunea, consistently recognizable subgenera were defined using the notation, configuration, and relative position (distance from the posterior suture of the whorls) of the primary spiral sculpture on the initial adult whorl of the shell. These characters were supplemented by the shape of the shells, especially the whorl profiles and proportions of shoulders and subsutural areas. The notation and configuration of primary spiral ribs on initial and subsequent adult whorls delimit three sub- genera of Neptunea, including N. (Golikovia) Habe and Sato, 1972. N. (Sulcosipho) Dall, 1916, and N. (Neptunea). These characters permit the identification of incomplete specimens. A strong, semireticulate pattern of spiral and axial ribs on the initial adult whorls in N. (Barbitonia) Dall, 1916, and the unique microstructure of its shell (Toco, 1974: 378-379). not shared by other Neptunea, in- dicate that the subgenus should be elevated to full generic rank and reassigned to the Buccinulidae. One hundred and thirty species of Cretaceous to Holocene “Neptunea” were reassigned to other caenogastropod genera in the most recent taxonomic revision of the genus (NELSON, 1974: Ap- THE VELIGER Vol. 21; No. 2 pendix B). Thus, Neptunea comprises 61 species—and sub- species—group taxa. including 31 extinct and 7 new taxa. This taxonomic revision and that of Gotikov (1963) facil- itate evaluation of the chronostratigraphy and zoogeog- raphy of Neptunea during the Neogene. ANCESTRY Neptunea, indigenous to the North Pacific, was thought to have evolved from a late Paleocene or Eocene complex also ancestral to Bruclarkia or Molopophorus (Melongenidae) and Siphonalia (Neptuneidae) (ILyina, 1963: 99; GOLI- KOV, 1963: 40; text fig. 59; KRISHTOFOVICH, 1964: 8-9; text fig. 1; STRAUCH, 1972: 173, based on Golikov; and Go.t- KOV & TZVETKOVA, 1972: 2; text fig. 1). However, the mor- phological specializations evident in the earliest species of these genera preclude their consideration as codescendant forms. Instead, Neptunea originated in the Oligocene from a complex also ancestral to Ancistrolepis altispirata (Nacao, 1928), the latter based on a single specimen from the Doshi Formation (provincial lower Oligocene) of Ho- shuyama, Fukuoka Prefecture, northern Honshu. Anets- trolepsis altispirata exhibits the most generalized morphol- ogy of any Eocene or Oligocene Japanese species referred by investigators to Neptunea or to its junior objective syn- onym Chrysodomus Swainson, 1840 (see OYAMA, MIzuNO & SAKAMOTO, 1960: 59-68 and Appendix B; MAcNEIL, 1973: 11g;and NELSON, 1973: 85; 1974: 45-46;and 1977: 375). Although details of the primary sculpture on the initial adult whorl and the apertural characters of A. altispirata are unknown, the distinctly angulate base of the body whorl is a distinguishing character in Ancistrolepis. Of the Explanation of Figures 2 to 7 (all Figures X 1 unless otherwise noted) Figure 2: Neptunea (Neptunea) pluricostulata Ilyina. UCMP 14530. UCMP loc. D3712, ex Central Scientific-Research Geo- logical Exploration Museum Academician F M. Chernyschev (CNIGR), Leningrad, U.S.S.R., courtesy of Yurii Gladenkov and Oleg Petrov. Etolon Formation, upper Miocene. Point Nepropusk, Kamchatka. Figure 3: Neptunea(Neptunea) unicostulata Ilyina. UCMP 14531. UCMP loc. D3712, ex CNIGR. Etolon Formation, upper Miocene. Point Nepropusk, Kamchatka. Figure 4: Neptunea (Neptunea) borealis (Philippi). CNIGR 3829/2. Ol’khov Formation, lower Pleistocene. Ust’ Kamchatsk, Kamchatka. X15 Figure 5: Neftunea (Neptunea) sp. A. aff. N. (N.) lyrata (Gme- lin). CNIGR 3586/1818/22. Limintev Formation, lower Pliocene. Karagin Island, U.S.S.R. Figure 6: Neptunea (Neptunea) lyrata altispira (Gabb). USNM 250502 (Catalog No. 36), rubber cast. USGS Cenozoic loc. M1876. Yakataga Formation, upper Miocene part. Chaix Hills, Malaspina district, Alaska. Figure 7: Neptunea (Neptunea) lyrata altispira (Gabb). UCMP 14532. UCMP loc. B7879. Rio Dell Formation', upper Pliocene. Humboldt County, California. " OcxE’s (1953) Wildcat Group and its five formations (ascend- ing: Pullen, Eel River, Rio Dell, Scotia Bluffs, and Carlotta) are adopted herein for U.S. Geological Survey usage. The biochrono- logy of the Wildcat formations was refined by FAUSTMAN (1964). Tue VELIcER, Vol. 21, No. 2 [Netson] Figures 2 to 7 Figure 3 tl VRS ~ are Vol. 21; No. 2 other Eocene or Oliogocene Japanese species of supposed Neptunea, only N.(N.) modesta (Kuroda in Homma, 1931) remains within the genus (NELSON, 1974: 46). Early Species in the North Pacific Neptunea originated and evolved in waters off northern Japan and Sakhalin in a low-boreal environment during the early to middle Oligocene. During that episode of cli- matic deterioration (ADDICOTT, 1969, 1970; INGLE, 1977), natural selection produced greater efficacy of reproduction in increasingly cooler waters. Descendants migrated north- ward during the late Oligocene to middle Miocene amel- ioration, when water temperatures off northern Japan and Sakhalin during the coldest part of the spawning seasons became too high for successful breeding. Many of the Oligocene and Miocene species referred un- certainly to Neptunea are based on specimens that lack preserved initial adult whorls. N. (Neptunea) modesta (Kuroda in Homma), of the N. (N.) pribiloffensis (Dall) stock, occurs in the Nenokami Sandstone (upper Oligo- cene) of Yoshida and Ogana, Saitama Prefecture (KANNO, 1960: 370-371) and the lower part of the Aoki Formation THE VELIGER Page 205 (lower Miocene) of Higashi-Kawate, Nagano Prefecture, Honshu (Kuropa in Homma, 1931: 78; also see NELSON, 1974: 200-201). Neptunea? (Golikovia?) ikusaensis Krish- tofovich in Krishtofovich and Ilyina, 1954 occurs in the upper part of the Takaradai Formation on the Kril’on Pen- insula and the lowermost part of the Machigar Formation (both upper Oligocene) along the Ikusa River in southern Sakhalin (ibzd., 108). Thus, N. (Golikova) and N. (Nep- tunea) were distinct taxonomically by the late Oligocene (Figure 14). Buccinaceans identified as Neptunea from the coeval I’khatun Formation on Karagin Island (Gxa- DENKOV, 1972: 141-142) (Figure 1) have been reassigned to Trominina (Gladenkov, in litt., June 28, 1976). Populations of Neptunea (Golikovia) sp. reached south- eastern Kamchatka (SALIN, 1972: 62; table 3; Ust’ Kam- chatsk Formation) during the early Miocene. Species of N. (Sulcosipho) and N. (Neptunea) occur in the latest early Miocene faunas in northern Sakhalin. Definite Neptunea, representing the three recognized subgenera and two of . the four stocks of N. (Neptunea), first appear in large num- bers in most of the (provincial) earliest middle Miocene molluscan faunas of Honshu, Hokkaido, Sakhalin, the Ku- ril Islands, Kamchatka, Karagin Island, the Alaska Pen- insula (rare), Kodiak Island (rare), and southeastern Figure 1 Localities cited in the text: (1) California; (2) Oregon; (3) Washington; (4) British Columbia, Canada; (5) southeast Alaska; (6) Middleton Island; (7) Kodiak Island; (8) Tugidak Island; (9) Alaska Peninsula; (10) Pribilof Islands; (11) Ber- ing Strait; (12) Koryak coast; (13) Bering Sea; (14) Karagin Island; (15) Komandor Islands; (16) Kamchatka; (17) Kolym coast; (18) Sea of Okhotsk; (19) Kuril Islands; (20) Sakhalin; (21) Primorye coast; (22) Hokkaido; {23) Korea Peninsula; (24) Honshu; (25) Shikoku; (26) North Pacific Ocean Page 206 Alaska. In the eastern portion of the Gulf of Alaska Tertiary Province, they are associated with cooler-water mollusks including the giant pectinid Patinopecten (Litu- yapecten) (MacNeIL, 1961: 228; KANNO, 1971: 52-55; AppicoTr, 1974: 191) and the neptuneid Beringius. There, Neptunea may have replaced ecologically Lira- cassis, or perhaps Eosiphonalia, of the warmer-water Oligocene and Mocene faunas. In subsequent Neogene Neptunea, especially within the nominate subgenus, tax- onomic diversity is consistently greater in the western North Pacific (compare Figures 20 and 21), where it reaches a maximum in the Hokkaido-Sakhalin region during the late Miocene and early Pliocene. The eastern North Pacific acme occurred during the late Pliocene in the Alaska region. ZOOGEOGRAPHIC REGIONS The numerous depositional basins of the Neogene of the North Pacific margin and adjacent Bering Sea have been placed within six geographic regions. In this way, provin- cialism in stage-age unit terminology can be avoided while viewing the trends in zoogeography and taxonomic diver- sity within Neptunea. The western regions include those of Shikoku-Honshu (33°-42° N, including northern Ky- ushu and the Korea Peninsula), Hokkaido-Sakhalin (42° 55° N, including Primorye and the southern and central Kurils), and Kamchatka (50°-60° N, 155°-170° E., includ- ing the northern Kurils, Komandor Islands, Karagin Is- land, and the Kolym and Koryak coasts). California (30°- 39° N), Oregon-Canada (39°-54° N), and Alaska (54°-60° N, 130°-180° W) comprise the eastern regions. The east- ern regions are equivalent in part to those used in AppI- coTt’s (1974: 188; text fig. 5) analysis of giant pectinids. In the zoogeographic charts (Figures 16-19), small circles rep- resent the nearest occurrences in time and space of species in the same subgenera or stocks in the opposite half of the North Pacific. THE VELIGER LATITUDE NORTH Vol. 21; No. 2 NORTH PACIFIC COAST PROVINCIAL CHRONOLOGY | iocene | PLIOCENE 50 40° 3o° OLIGOCENE MIOCENE PLIOCENE 5 24 TIME (M. Y.) Figure 14 Zoogeographic and chronostratigraphic distribution of Neptunea in the North Pacific and adjacent Bering Sea during the late Cenozoic. GEOCHRONOLOGY The ages assigned to the boundaries of the Neogene chron- ostratigraphic units in the eastern North Pacific conform to those used by Appicorr (1976: text fig. 1; 1977: text fig. 3). They are based on the international standard of BErc- GREN (1972) and BERGGREN & VAN CouveERING (1974). Explanation of Figures 8 to 13 (all Figures X 1) Figure 8: Neptunea (Neptunea) lyrata altispira (Gabb). USNM 250503. USGS Cenozoic loc. M1741. Yakataga Formation, lower Pleistocene part. Middleton Island, Alaska. Figure 9: Neptunea (Neptunea) pribiloffensis pribiloffensis (Dall). USNM 250504. USGS Cenozoic loc. M3966. Elk River Formation, lower Pleistocene. Curry County, Oregon. Figure 10: Neptunea (Golikovia) smirnia (Dall). USNM 250505. USGS Cenozoic loc. M2106. Capistrano Formation, lower Plio- cene part. Orange County, California. Figure 11: Neptunea (Sulcosipho) lawsoni (Martin). CAS Geo- logy 59073. CAS Geology loc. 117. Rio Dell Formation, upper Pliocene. Humboldt County, California. Figure 12: Neptunea (Sulcosipho) sp. B. aff. N. (S.) tabulata (W. Baird). USNM 250506. USGS Cenozoic loc. M1882. Yakataga Formation, lower Pliocene part. Karr Hills, Malaspina district, Alaska. Figure 13: Neptunea (Sulcosipho) tabulata (W. Baird). USNM 250507. USGS Cenozoic loc. M2753. Fernando Formation, upper Pliocene part. Orange County, California. THE VELIGER, Vol. 21, No. 2 [NeLson] Figures 8 to 13 Figure rr Vol. 21; No. 2 incial Pomme [mat i. Ea Neptunea NortH Paciric (30° - 60°N) Lower Upper 5 Laat py Species-group taxa Figure 15 Chronostratigraphic occurrence and taxonomic diversity of Neptunea in the North Pacific and adjacent Bering Sea during the late Cenozoic. Provincial stage-age units for the Neogene molluscan se- quences in southern Alaska have not been established as yet, although ALLIson (1977a: text fig. 1; 1977b: 876) correlated the mollusk-bearing formations of the Gulf of Alaska with Addicott’s chronostratigraphic units. In the western North Pacific, subseries-subepoch units based principally on the chronostratigraphic framework of GLa- DENKOV (1972, 1974) are used in displaying trends in tax- Onomic diversity and zoogeography within Neptunea. Neptunea (Sulcosipho) MORPHOLOGY Medium to large, slender elongate-fusiform shells, with tabulate to subtabulate or rounded whorl shoulders and subsulcate to channeled subsutural shelves distinguish taxa in Neptunea (Sulcosipho). For all of the subgenera, the lengths of adult shells have been classed as: “small;’ 50-75 THE VELIGER Page 207 mm; “medium;’ 75-125mm; ‘large,’ 125-175mm; and “very large,’ more than 175 mm. The notation of the pri- mary spiral ribs on the first adult whorl is (A1a:)B1C:(Ds); B is ata position posterior to the middle of the spire whorls. The B, C, and D ribs, rounded to subcrenelate in cross- section and often bifurcated by narrow grooves, are devel- oped strongly on the initial adult whorls and separated by narrower interspaces. Secondary spiral ribs fill each inter- space on second and third adult whorls. Tertiary spirals, inserted anteriorly, alternate regularly with the stronger elements. Shell morphology in N. (Sulcosipho) is more sim- ilar to that of N. (Neptunea) than to N. (Golikovia). ZOOGEOGRAPHY AND TAXONOMIC DIVERSITY Taxa in Neptunea (Sulcosipho) were distributed circum- boreally in the North Pacific during the middle and late Miocene. Specimens of N. (S.) “sachalinensis’”” Khomenko, 1938, from the Kaskadn (upper lower Miocene) and Ven- geri (middle Miocene) Formations on the Shmidt Penin- sula of northern Sakhalin, represent the earliest occur- rence of N. (Sulcos:pho) in the western North Pacific. Spe- cies of the subgenus occur throughout the western North Pacific during the late Miocene (Figure 16). They occur only in the Shikoku-Honshu region during the Pliocene, where maximum taxonomic diversity in the Neogene of the western North Pacific is reached early in the epoch (Figure 20). Neptunea (S.) lamellosa Golikov, 1962, occu- pied northern portions of the Sea of Okhotsk in the Pleis- tocene. An unnamed species (Figure 12) of Neptunea (Sulco- sipho), ancestral to N. (S.) tabulata (W. Baird, 1863) (Fig- ure 13) from the lower part of the Yakataga Formation (lower middle Miocene part) in the Yakataga district of the Gulf of Alaska Tertiary Province, represents the ear- liest known occurrence of N. (Sulcosipho) in the eastern North Pacific (Figure 17). Subsequent populations of this species and a closely-related new species occurred as far north as Middleton Island (Figure 1) in the Gulf of Alaska through the early Pleistocene. Other species extended their ranges southward to the Canada-Oregon region during the early Pliocene, where maximum taxonomic diversity within N. (Sulcosipho) occurred late in the epoch (Figure 21). They reached the California region in the late Plio- cene and Pleistocene. This trend parallels the inferred progressive cooling of inshore waters during the Pliocene (DurHAM, 1950; ADDICOTT, 1969, 1974). Neptunea (S.) andersoni (Martin, 1914), restricted to the early Pliocene of the southernmost portion of the Oregon-Canada region, evolved from emigrants of the N. (S.) uwasoensis (Otuka, 1935) lineage of the western North Pacific. Latitude North Page 208 Neptunea (Golikovia) MorRPHOLOGY Has & SATO (1972: 2, 6) proposed Neptunea (Golikovia) as a full genus, but the radular morphology and number they thought to be unique also occur in two species of N. (Neptunea) (see GoLikov. 1963: 29, 75). Thus, separate generic status for Golikovia is not appropriate. The nota- tion and configuration of primary spiral ribs indicate that N. (Golikovia) is more closely related to Neptunea than to any other neptuneid genus. Species of Neptunea (Golikovia) exhibit medium to very large, subelongate-fusiform shells, with slender to mod- erately inflated, convex whorls that have rounded, non- tabulate shoulders (Figure zo). Seven or eight unique, equal-sized, rounded to subcrenelate primary spiral ribs on posterior adult whorls distinguish the subgenus. Their no- tation is (A1,a1)BiCiDiE:(F:)(G1)(H:); B is located near the posterior suture of the spire whorls. These spiral ribs are separated on posterior whorls by interspaces equal to or slightly wider than the ribs. Subordinate ribs are reduced and all spiral sculpture usually weakens to obsolescence anteriorly on the penultimate and body whorls. NORTH WEST PACIFIC COAST PROVINCIAL CHRONOLOGY OLIGOCENE MIOCENE PLIOCENE | prets- [ee [me SAKHALIN-HOKKAIDO REGION’. _ / / 4 / Yo KAMCHATKA i y REGION Visy Explanation can. (Sulcosipho) @2 N. (Golikovia) © NE PACIFIC OLIGOCENE MIOCENE PLIOCENE |rocrne 24 Time (m.y.) 5 - Figure 16 Zoogeographic and chronostratigraphic distribution of Neptunea (Sulcosipho) and Neptunea (Golikovia) in the western North Pacific and adjacent Bering Sea during the late Cenozoic. TOCENE lower Latitude North THE VELIGER 60° 50 30° Vol. 21; No. 2 ZOOGEOGRAPHY AND TAXONOMIC DIVERSITY Taxa in Neptunea (Golikovia) were distributed circum- boreally in the North Pacific during the middle Miocene. Following uncertain records from upper Oligocene strata on Sakhalin (KRISHTOFOVICH 7m KRISHTOFOVICH & ILYINA, 1954) and lower Miocene strata on Kamchatka (SALIN, 1972), the next known occurrence of the subgenus in the western North Pacific is N.? (G.?) ntkkoensis (non) No- mura, 1937 (Nova, 1962) from the Kubiki Formation (middle Miocene) of Tanaoka, Niigata Prefecture, Hon- shu. Species of N. (Golikovia) migrated to the southern portion of the Shikoku-Honshu region in the late Miocene. Their distribution was restricted to the Hokkaido-Sakhalin and Shikoku-Honshu regions during the Pliocene, and to the latter region alone in the Pleistocene, where N. (G.) fukueae Kira, 1959 represented the subgenus. Southern populations of this species apparently extended their range in the submerged Oyashio water mass southwestward to Shikoku during the late Pleistocene and Holocene (Fig- ure 16). The earliest species of Neptunea (Golikovia) from the eastern North Pacific is N. (G.) plafkeri Kanno, 1971 from the lower part of the Yakataga Formation in the Yakataga NORTH EAST PACIFIC COAST PROVINCIAL CHRONOLOGY OLIGOCENE MIOCENE PLIOCENE | py ps- [see [ever ete isos | vee] re] \ LIMB MB hig ALASKA REGION OREGON-CANADA REGION explanation za N. (Sulcosipho) N. (Golikovia) O Nw PAcIFic PLEIS- 24 Time (m.y.) Figure 17 Zoogeographic and chronostratigraphic distribution of Neptunea (Sulcosipho) and Neptunea (Golikovia) in the eastern North Pacific and adjacent Bering Sea during the late Cenozoic. Vol. 21; No. 2 district and the Topsy Formation (both Miocene) in the Lituya district of southeastern Alaska (Figure 17). In the early Pliocene, N. (Golikovia) expanded rapidly southward to California. Its species were restricted to the southern Oregon-Canada and California regions during the late Pliocene. Maximum taxonomic diversity within the sub- genus in the Neogene of the eastern North Pacific occurred in the California region during the late Pliocene (Figure 21). Neptunea (G.) phoenicea (Dall, 1891), whose modern distribution extends as far north as Juneau, Alaska, may have evolved from a western North Pacific lineage in the early Pliocene. Both N. (Golikovia) and N. (Sulcosipho) display lesser species diversity in the Neogene compared to that of N. (Neptunea) (compare Figures go and 21). Neptunea (Neptunea) Small to very large, subfusiform to fusiform shells, with shortened to sub-elongate spires and angular subtabulate to rounded convex whorls distinguish species of Neptunea (Neptunea). They have reduced penultimate whorls and moderately to greatly inflated body whorls compared to shells of the other subgenera. Subsutural shelves are sloped gently and not subsulcate or channeled on anterior whorls. The notation of the initial spiral sculpture varies, but usu- ally contains well-developed B and C primary ribs; B is lo- cated at, or just anterior to, the middle of the spire whorls. The notation and configuration of spiral ribs define four stocks of closely-related species lineages within N. (Nep- tunea): N.(N.) lyrata(Gmelin, 1791), N. (N.) pribiloffensis (Dall, 1919), N. (N.) despecta (Linnaeus, 1758), and N. (N.) eulimata (Dall, 1907). Neptunea (Neptunea) eulimata (Dall) Stock Species in the N. (N.) eulimata (Dall) stock are character- ized by large to very large, elongate-fusiform shells with shallow to inflated convex or rounded subtabular whorls. Often the spire or all whorls are especially slender. Very thin, shallowly to moderately-rounded convex primary ribs, with the notation (Ai,a:1)B:CiDi, increase in width anteriorly to a maximum of one millimeter. Interspaces between the B and C ribs vary in width to twice that of the ribs. Single secondaries are inserted early on posterior whorls; spacing and number of secondary and tertiary ele- ments become irregular anteriorly. These shells often bear thin to medium-sized, widely-spaced axial lobes or lamel- lae. The stock is endemic to the western North Pacific and is represented initially by N. (N.) iwaii Hatai, Masuda, and Suzuki, 1961 from the Hamada Formation (lower Pliocene) and coeval units in Aomori Prefecture, northern THE VELIGER Page 209 Honshu. From this species evolved the two Holocene spe- cies of the northern portion of the Shikoku-Honshu region and southern part of the Hokkaido-Sakhalin region (Fig- ure 18). Neptunea (Neptunea) lyrata (Gmelin) Stock MORPHOLOGY In the N. (N.) lyrata (Gmelin) stock, the notation of the initial sculpture is (a;)B,(C,,c,) (D,,d,). The B spiral rib, lo- cated usually at the maximum diameter of the spire whorls, is stronger than the C or Dribs when the latter pair are present. These rounded and protuberant spirals en- large anteriorly to widths of more than two millimeters. Interspaces between the B and C primaries on the spire whorls are narrower than the ribs. Secondary and tertiary spiral elements are less well-developed than those of spe- cies in the other stocks. ZOOGEOGRAPHY AND IT AXONOMIC DIVERSITY The Neptunea (N.) lyrata (Gmelin) stock was distributed circumboreally in the North Pacific during the middle and late Miocene; it has occupied the continental shelf and uppermost slope in the Bering Sea since at least the late Pliocene. The earliest known species of the stock in the western North Pacific is represented by specimens of N. (N.) “sachalinensis’ Khomenko, 1938, from the upper Kas- kadn (upper lower Miocene) and lower Vengeri (lower middle Miocene) Formations on the northwestern Shmidt Peninsula of Sakhalin. Neptunea (N.) pluricostulata Il- yina, 1939 (Figure 2) and N. (N.) unicostulata Ilyina, 1939 ( Figure 3) occur in the middle Miocene strata of Sakhalin and Kamchatka (ILYINA, 1939, 1954, 1963; GLADENKOV, 1972). Subsequently, species of this stock were distributed widely in all three regions of the western North Pacific from the late Miocene through the Pleistocene (Figure 18); they attained their maximum taxonomic diversity in the Neogene during the early Pliocene (Figure 20). In the eastern North Pacific, the Neptunea (N.) lyrata (Gmelin) stock is represented initially by an unnamed spe- cies of the arcto-boreal N. (N.) heros (Gray, 1850) lineage. It and N. (N.) pluricostulata Ilyina, from the western North Pacific, occur in the lower part of the Yakataga For- mation (lower middle Miocene part) of the Katalla and Yakataga districts in southeastern Alaska (Figure 19). The widely distributed N. (N.) lyrata altispira (Gabb, 1869) (Figures 6-8) evolved from the latter species in the Gulf of Alaska during the latest middle or earliest late Miocene. The N. (N.) lyrata stock was confined to the Alaska region Latitude North Page 210 THE VELIGER Vol. 21; No. 2 NORTH WEST PACIFIC COAST PROVINCIAL CHRONOLOGY OLIGOCENE MIOCENE PLIOCENE @ 60° NORTH EAST PACIFIC COAST PROVINCIAL CHRONOLOGY MIOCENE PLIOCENE [some [twee [mae [sone] ve [or WW Log 3 KAMCHATKA Le 50 50° ee Explanation £E ZaN. (N.) lyrata stock Pa @AN. (N.) pribiloffensis stock © ESN. (N.) despecta stock ‘ os O Nw PACIFIC SAKHALIN-HOKKAIDO_ REGION 2 Ss 40° 7 40° ose 40'| “OREGON-CANADA. REGION, (0 eee eee CALIFORNIA REGION Explanation . za N. (N.) lyrata stock <=; N. (N.) despecta Beer Sati we N. (N.) pribiloffensis Y stock ONE PACIFIC 30° stock GS N. (N.) eulimata stock 30° OLIGOCENE MIOCENE PLIOCENE |7oti,, | OLIGOCENE silk MIOCENE Deal PLIOCENE | tocene 24 Time (m.y.) 5 o 24 Time (m.y.) 5 ° Figure 18 Figure 19 Zoogeographic and chronostratigraphic distribution of Neptunea (Neptunea) stocks in the western North Pacific and adjacent Bering Sea during the late Cenozoic. during the Miocene and early Pliocene and expanded southward to the Canada-Oregon region in the late Plio- cene and Pleistocene, the interval of its maximum taxo- nomic diversity in the eastern North Pacific (Figure 21). Despite numerous literature citations to the contrary, spe- cies of this stock do not occur in the Neogene or Quater- nary of the California region. Neptunea (Neptunea) pribiloffensts (Dall) Stock MorRPHOLOGY The general notation of the spiral ribs on shells of species in the Neptunea (N.) pribiloffensis (Dall) stock is (a1)B:Gi(D:). These shells exhibit rounded convex B, C, and D ribs, which are nearly of equal size on posterior whorls. On anterior whorls, the ribs are usually less than twomm in width. The C rib is located at the maximum diameter of the whorls. Interspaces between the B and C ribs on middle and anterior whorls are broader than the Zoogeographic and chronostratigraphic distribution of Neptunea (Neptunea) stocks in the eastern North Pacific and adjacent Bering Sea during the late Cenozoic. ribs. Strong, single secondary and multiple tertiary spirals are developed more prominently on these shells than those of the N. (N.) lyrata (Gmelin) stock. ZOOGEOGRAPHY AND TAXONOMIC DIVERSITY Members of the Neptunea (N.) pribiloffensis (Dall) stock were distributed circumboreally in the North Pacific dur- ing the late Miocene. They have occupied the continental shelf and uppermost slope in the Bering Sea since at least the late Pliocene. The known fossil record of this stock does not support STRAUCH’s (1972: text fig. 2) suggestion that N. (N.) pribiloffensis (Dall) originated in the North’ Atlantic. The record of this species and its stock is confined to the North Pacific and southern Bering Sea. Four distinct lineages evolved from Oligocene and Mio- cene populations of Neptunea (N.) modesta (Kuroda in Homma). This species occurs initially in the Nenokami Sandstone (upper Oligocene) of Chigaya and the Iwadono- zawa, Saitama Prefecture (KANNO, 1960: 370) and the Vol. 21; No. 2 lower part of the Aoki Formation (lower Miocene) of Kashiwa-zawa, northern Nagano Prefecture, Honshu (Ku- RoDA in HomMa, 1931: 78 and explanation plt. 13). Spe- cies in these lineages occur in early Miocene faunas of the Shikoku-Honshu and Hokkaido-Sakhalin regions and in all three regions of the western North Pacific during the middle and late Miocene (Figure 18). Text citations re- port N. (N.) pribiloffensis (Dall) and related species from the lower part of the Enemten Formation (lower Plio- cene) of central-western Kamchatka (SINEL’NIKOVA, 1969: 34; SINEL’NIKOVA & DRUSHCHITS, 1971: text fig. 2), where it occurs with Fortipecten kenyoshiensis (Chinzei), and in approximately coeval strata near Rekinniki and Pleisto- cene units elsewhere in northern Kamchatka (GOLIKov, 1963: 150-151; text fig. 91). If verified, these would dem- onstrate a continuous record of the stock in the northern Hokkaido-Sakhalin and Kamchatka regions from the mid- dle Miocene through the Pleistocene; as a related species occurs in the Mayamraf Formation (middle to upper Mio- cene) on the Shmidt Peninsula (KHOMENKO, 1934: 69) and in the lower part of the Maruyam I Formation (upper Mio- cene) along the Liutoga River in southern Sakhalin (IL- YINA in KRISHTOFOVICH & ILYINA, 1954: 244). Neptunea (N.) pribiloffensis (Dall) also may have spread into the eastern portion of the Kamchatka region from the eastern Bering Sea during the Pleistocene. A geographical restric- tion of the stock’s southern taxa began in the Pliocene. The Pliocene and Pleistocene N. (N.) frater frater (Pilsbry, 1901) and N. (N.) frater ‘“kuroshio’ Oyama, 1958 occur only in the Shikoku-Honshu region. In the Neogene of the eastern North Pacific, the stock is consistently much less diverse taxonomically (peak: late Pliocene) than in the western North Pacific (peak: late Miocene) (compare Figures 20 and 21). Neptunea (N.) modesta (Kuroda in Homma) from the Bear Lake Forma- tion (upper Miocene) near Port Moller on the Alaska Pen- insula represents the earliest known occurrence of the stock in the eastern North Pacific. A closely-related, new species occurs in the lower part of the Tachilni Formation (upper Miocene to lower Pliocene) south of Fort Randall, Alaska Peninsula. Neptunea (N.) pribiloffensis (Dall) (Figure 9) occurs initially in the Tugidak Formation (upper Pliocene and lower Pleistocene) on Tugidak Island, Alaska (Figure 1)and questionably in the Rio Dell Formation (upper Plio- cene) in northern California. This species originated from, or shared a common ancestry with, N. (N.) ‘gigantea’ (KHOMENKO, 1934) and a closely-related, unnamed species from middle and upper Miocene strata on Sakhalin and lower Pliocene sediments on Kamchatka. The stock was distributed widely in the eastern North Pacific during the Pleistocene (Figure 19). THE VELIGER Page 211 Neptunea (Neptunea) despecta (Linnaeus) Stock MoRPHOLOGY Species in this stock are distinguished by primary spiral ribs which are rounded convex, subrounded, or triangular in cross-section and have the notation (a1)B:Ci(d:). The pri- mary ribs attain widths of less than 2mm on anterior whorls. The interspace between the B and Cribs is broader than the ribs on the middle and anterior whorls. Secondary and tertiary spiral elements are developed strongly on ante- rior whorls. Nodes or tubercles occur often on the primary and some secondary ribs of anterior whorls. Occasionally these whorls bear varices and lamellae of low-relief. ZOOGEOGRAPHY Although no species of this stock is known from the Neo- gene deposits of the North Pacific or Bering Sea, Neptunea (N.) borealis (Philippi, 1850) (Figure 4) occurs in the Ol-— khov Formation (lower Pleistocene) of the Tusatuvayam [Anvilian] Transgression near Ust’ Kamchatsk, Kam- chatka and on Karagin Island (PETRov & KHoreEvA, 1968; Petrov, unpublished data; NELSON, 1974: 258-259) (Figure 18). This species occupied most of the continental shelf in the Bering Sea during the Pleistocene. In the eastern Ber- ing Sea, it occurs initially in middle Pleistocene strata of the Einahnuhtan Transgression on St. Paul Island in the Pribilofs (D. M. Hopkins, unpublished data; NEtson, 1974: 258) (Figure 19). Neptunea in the Arctic and North Atlantic During the late Pliocene Beringian Transgression, Nep- tunea species formed part of the spectacular dispersal of Pacific, or Pacific-related, boreal mollusks through Bering Strait, across the Arctic, and into the North Atlantic (Mac- NEIL, 1957: 113; 1965: 68-69; GOLIKov, 1963: 51-53; fig. 60; DuRHAM & MACNEIL, 1967: 336; Hopkins, 1967: 59; 1972: 124-125; STRAUCH, 1972: text fig. 2; MACNEIL, 1973: 56; NELSON, 1973: 85). Species in N. (Sulcosipho) and the N. (N.) lyrata (Gmelin) and N. (N.) despecta (Linnaeus) stocks occupied the Pliocene and Pleistocene basins of Ice- land and the North Sea; those of N. (Sulcostpho) expanded into the western Mediterranean during the Pleistocene (NELSON, 1973: 85; 1974: 52-573 1977: 375-376). The known record of Neptunea in the western North Atlantic dates from the late Pleistocene, when it extended as far south as New Jersey. Modern Neptunea occur over nearly the entire continental shelf of the Arctic Ocean, north of Page 212 THE VELIGER Vol. 21; No. 2 3 HONSHU- SAKHALIN- | KAMCHATKA HONSHU- SAKHALIN- KAMCHATKA peers NW PACIFIC SHIKOKU HOKKAIDO (50°-60°N) SHIKOKU HOKKAIDO (50°-60°N) (33°-42°N) | (42°-55°N) |(155°-170°E) | (33°-42°N)_ | (42°-55°N) | (155°-170°E) Pliocene : S Neogene Lower Oligocene ere ewe Species-group taxa Figure 20 Chronostratigraphic occurrence and taxonomic diversity of western North Pacific and adjacent Bering Sea during the late Neptunea (Sulcosipho), N. (Golikovia), and N. (Neptunea) in the Cenozoic, OREGON- ALASKA OREGON-= ALASKA PROVINCIAL , G a Be N Pacific CALIFORNIA CANADA (54°-60°N) CALIFORNIA CANADA (54° -60°N) 1 (30°-39N°) | (39°-54°N) [(130°-180° W)}] (30°-39N°) | (39°-54°N) }(130°-180° W) [Poon |_| Upper | Pliocene | tame | | i Upper | | Miocene | Chronostratigraphic occurrence and taxonomic diversity of eastern North Pacific and adjacent Bering Sea during the late Neptunea (Sulcosipho), N. (Golikovia), and N. (Neptunea) in the Cenozoic, Neogene Ser ere eww Species-group taxa Figure 21 Vol. 21; No. 2 Martha’s Vineyard, Massachusetts, in the western North Atlantic, and north of Cape Spartel, Morocco, in the east- ern North Atlantic (NELSON, 1974). SUMMARY Neptunea evolved in waters off northern Japan and Sak- halin during the early Oligocene from taxa sharing a common ancestry with Ancistrolepis altispirata (Nagao). Thus it is a more ‘‘modern” taxon than portrayed pre- viously. Neptunea species spread north and east during the late Oligocene and early Miocene. By the early middle Miocene, Neptunea occupied the rim of the North Pacific and adjacent Bering Sea from Honshu to southeastern Alaska. Regions south of Alaska were peripheral to the major evolutionary center of the genus in the Neogene and Quaternary. Several species occurred south of Alaska be- ginning in the Pliocene. Taxonomic diversity increased significantly during the middle Miocene and reached some- what higher levels during the Pliocene. Species of N. (Nep- tunea) were distributed widely during that interval. Those of the other subgenera were more conservative, both in their evolution and geographic distribution; they were re- stricted to latitudes south of Alaska after the Pliocene. Taxonomic diversity within N. (Neptunea) increased even more during the latest Pliocene and Pleistocene, as the ge- nus expanded into the Arctic, North Atlantic, and the western Mediterranean. ACKNOWLEDGMENTS This investigation, based largely on my dissertation studies (NELSON, 1974), has benefitted greatly from discussions with colleagues in North America, western Europe, the So- viet Union, and Japan. Especially significant were the con- tributions of Stearns MacNeil (retired), Warren Addicott, David Hopkins, Louie Marincovich, and George Plafker of the U.S. Geological Survey, Menlo Park, California, Aleksandr Golikov of the Zoological Institute, Leningrad, and Yurii Gladenkov and Oleg Petrov of the Geological Institute, Moscow. They gave generously of their time and unpublished data. Also, Addicott and Marincovich re- viewed this paper. National Science Foundation Travel Grant EAR 76-16574 funded the presentation of anearlier version of this paper at the First International Congress on Pacific Neogene Stratigraphy in Tokyo during May 16-21, 1976. That paper (NELSON, 1977) was completed while I THE VELIGER Page 213 was a Research Fellow in the Museum of Paleontology at the University of California, Berkeley, during 1975-1976. FOSSIL LOCALITIES United States Geological Survey (USGS) : M1741. Cliff near SW end of Middleton Island, Middleton Is- land B-7 quad. (1 : 63 360, 1955), Alaska. Yakataga Forma- tion, about 1013m above base of 1181m exposed section, as determined by PLarKer (1971: 129), lower Pleistocene part M1882. Karr Hills, at 60°08’N, 148°19’ W, Bering Glacier quad. (1: 250000, 1959), Malaspina district, Alaska. Yakataga Formation, from interval above 975m above base of 2130m Yakataga exposed section, lower Pliocene part Maio6. In artificial cut, elevation about 149.4m, on N side of Deep Canyon, 1342m S and 731m W of NE corner [pro- jected] Sec. 13, T.8S., R.8 W, Dana Point quad. (7.5 min., 1: 24000, 1949), Orange County, California. Uppermost part of Capistrano Formation, lower Pliocene M2753. In artificial cut near top of bluff overlooking Upper Newport Bay, elevation about 27.4m, approximately 837.5m SE and 776.6m SW from N corner Irvine Block 52, Newport Beach quad. (7.5 min., 1 : 24.000, 1965). Fernando Forma- tion, lower part of upper unit, upper Pliocene M3966. Psephidia beds exposed in slumped blocks SE of mouth of Elk River, 91.4m S and 60.9m E of NW corner of Sec. 18, T. 32S., R. 15 W, Cape Blanco quad. (15 min., 1 : 62 500, 1954), Curry County, Oregon. Elk River Formation, lower Pleistocene University of California (Berkeley), Museum of Paleontology (UCMP) : B7644. In E side of bed of Eel River, from 441.9m to 472.4m NE of U.S. Highway 1o1 bridge, in center of SE, SW, Sec. 5, T.1 N., R. 1 E., Scotia quad. (15 min., 1 : 62500, 1951). Humboldt County, California. Rio Dell Formation, massive dark gray sandy siltstone about 376.4m above base, upper Pliocene (? = CAS loc. 117) B7879. Cliff, about 6.1m E of railroad trestle and 141.7m N of place where Nanning Creek passes under the railroad tracks, in center of NE, Sec. 5, T.1 N., R.1 E., Fortuna quad. (15 min., 1 : 62500, 1942), Humboldt County, California. Rio Dell Formation, 143.3m below top (1213.9m above base), upper Pliocene D3712. Point Nepropusk, about 1ookm N of Tichjl’ River, west coast of Kamchatka, U.S.S.R. Etolon Formation (Kavran Group), upper Miocene of GLrapENKov (1972) California Academy of Sciences (CAS) : 117. Along E bank of Eel River, 1.2km N of Scotia, “Scotia Quad.,” Humboldt County, California. Wildcat Group, prob- ably lower part of Rio Dell Formation, upper Pliocene (col- lected in 1912; probably equivalent to UCMP loc. B7644) Page 214 Literature Cited Appicotr. WARREN OLIVER 1969. Tertiary climatic change in the marginal northeastern Pacific Ocean. Science 165: 583 - 586; 3 text figs. 1970. Latitudinal gradients in Tertiary molluscan faunas of the Pa- cific Coast. Paleogeogr., Paleoclimat., Paleoecol. 8 (4): 287-312; 7 text figs. 1974. Giant pectinids of the eastern North Pacific margin: signifi- cance in Neogene zoogeography and chronostratigraphy. Journ. Paleon. 48 (1): 180-194: 2 plts.; 7 text figs. 1976. Neogene molluscan stages of Oregon and Washington. Proc. Ann. Mtg., Soc. Econ. Paleont. Mineral., Pacif. Sect., San Francisco, Calif. 51: 95-115: 5 plts.: 6 text figs.: 1 table (April 1976) 1977. Neogene chronostratigraphy of nearshore marine basins of the eastern North Pacific; International Congress Pacific Neogene Strati- graphy, Proc., Tokyo, Japan, 1976: 151-175 ALLIsoNn, RICHARD Case 1965. Apical development in turritellid classification with a descrip- tion of Cristispira pugetensis gen. et sp. nov. Palaeontology 8: 666 - 680; plt. 92; 1 table (December 1965) 1977a. Late Oligocene through Pleistocene molluscan faunas in the Gulf of Alaska region. In: TsuNemasa Sato « Hirosui Ujue, eds. Proc. First Internat. Congr. Pacif. Neogene Stratigraphy, Tokyo, 1976. Tokyo, Sci. Council Japan & Geol. Soc. Japan: 313 - 316; 1 text fig.; 1 table (July 1977) 1977b. Late Paleogene and Neogene molluscan faunas of the Gulf of Alaska region: correlation, paleoclimatology, and paleozoogeography. Gulf of Alaska region. In: TsuNeMasa Saito & Hirosnwi Uyjue, eds. Bairp, WILLIAM 1863. Descriptions of some new species of shells, collected at Van- couver Island and in British Columbia by J. K. Lord Esq., naturalist to the British North American Boundary Commission in the years 1858- 1862. Proc. Zool. Soc. London for 1863: 66-70 (10 Feb. 1863) BERGGREN, WILLIAM ALFRED 1972. A Cenozoic time-scale — some implications for regional geo- logy and palcohiogeography. Lethaia 5 (2): 193-215; 9 text figs. Berccren, WILLIAM ALFRED & JOHN ANTHONY VAN COUVERING 1974. The late Neogene: biostratigraphy, geochronology, and paleo- climatology of the last 15 million years in marine and continental se- quences. Palaeogeogr., Palaeoclim., Palaeoecol. 16 (1/2): 1-216; 15 text figs.: 12 tables Dart, Wittiam Heatey 1891. Scientific results of exploration by the U.S. Fish Commission steamer Albatross. No. XX. On some new or interesting West Amer- ican shells obtained from the dredgings of the U. S. Fish Commission steamer Albatross in 1888, and from some other sources. Proc. U. S. Natl. Mus. 14 (849): 173-191; plts. 5-7 (24 July 1891) 1907. Descriptions of new species of shells, chiefly Buccinidae, from the dredgings of the U.S.S. “Albatross” during 1906, in the northwestern Pacific, Bering, Okhotsk, and Japanese Seas. Smithson. Misc. Coll. 50 (1727): 139-173 (9 July 1907) 1916. Prodrome of a revision of the chrysodomoid whelks of the boreal and Arctic regions. Proc. Biol. Soc. Washington 29: 7-8 (25 January 1916) 1919. Descriptions of new species of Mollusca from the North Paa}fic Ocean in the collection of the United States National Museum. Proc. U.S. Natl. Mus. 56 (2295): 293 - 371 (30 August 1919) Duruam, JoHN Wyatr 1950. Cenozoic marine climates of the Pacific coast. Geol. Soc. Amer. Bull. 61: 1243 - 1264; 3 text figs. DuruaM, JoHN WyvatTT & Francis STEARNS MACNEIL 1967. Cenozoic migrations of marine invertebrates through the Bering Strait region. In: D. M. Hopxins (ed.) The Bering Land Bridge. Stanford, Calif.: 326-349; 4 tables FausTMAN, WALTER FRANCIS 1964. Paleontology of the Wildcat Group at Scotia and Centerville Beach, California. Univ. Calif. Publs. Geol. Sci. 41 (2): 97-159; pits. 1-3; 7 text figs. (17 December 1964) Gass, Witit1aM More 1869 [1866-1869]. Paleontology of California 2: Section 1 [Tertiary in- vertebrate fossils}. Geol. Surv. Calif. 124 pp.; 18 plts. [part 1 (Descriptions of new species) pp. 1-38; plts. 1-13 (1866); part 2 (Descriptions of new species, cont.) pp. 39 - 64; plts. 14-18 (probably early 1869); part 3 (Synopsis of the Tertiary invertebrate fossils of California) pp. 65 - 124 (early 1869)] [dating: Stewart, 1927; types: Stewart, 1930] THE VELIGER Vol. 21; No. 2 GLapENKov, Yuri BorisovicH 1972. | Neogen Kamchatki (Voprosy biostratigrafii i paleoekologii) [Neogene of Kamchatka (Problems of biostratigraphy and paleoeco- logy )]. Trudy Akad. Nauk SSSR, Ord. Trudob. Krash. Znameni, Geol. Inst. 214: 1- 251; plts. 1-8; 48 text figs.; 37 tables 1974. | The Neogene period in the subarctic sector of the Pacific. In Yvonne Herman (ed.), Marine geology and oceanography of the Arctic seas. Springer Verlag, New York: 271 - 281; 3 text figs.; 2 tables GMELIN, JOHANN Friepricn, ed. 1791. Vermes Testacea: In Caroii a Linné Systema naturae per regna tria naturae . .. Editio decima tertia, aucta, reformata. Lipsiae, Rudolphipoli, Litteris Bergmannianius, I [VI]: 3021 - 3910 Go.ixov, ALEKSANDR NIKOLAYEVICH 1962. Novye vidy bryukhonogikh molliuskov roda Neptunea Bolten (Gastropoda, Prosobranchiata) iz dal’nevostochnykh morei SSSR [New species of gastropods of the genus Neptunea Bolten from the far-eastern seas of the USSR (Gastropoda, Prosobranchia)]. Trudy Zool. Inst. Akad. Nauk SSSR go: 3 - 10; 3 plts; 3 maps 1963. | Bryukhonogie molliuski roda Neptunea Bolten [Gastropod mol- lusks of the genus Neptunea Bolten]. Fauna SSSR, Molliuski 5 (1): [nov. ser. (85)]: 1-217; 28 plts.; 98 text figs. Go.ikov, ALEKSANDR NIKOLAYEvicH & N. L. TzvetTKova 1972. The ecological principle of evolutionary reconstruction by marine animals. Mar. Biol. 14: 1 - 9; 5 text figs. Gray, JoHN Epwarp 1850. Description of a new species of Chrysodomus, from the mouth of the Mackenzie River. Proc. Zool. Soc. London for 1850 [XVIII}: 14-15; illustr. 1848 - 1860, vol. V, Mollusca, plt. 7 (12 Nov. 1850) Hase, TADASHIGE & JUNKO SaTo 1972. A classification of the family Buccinidae from the North Pacific. Proc. Japan. Soc. Syst. Zool. 8: 1-8; 2 plts. (in Japanese, English summary ) (November 1972) Hata, Kotora, Kéicu1r6 Masupa & Yoko Suzuki 1961. A note on the Pliocene megafossil fauna from the Shimokita Pen- Saito Ho-on (August 1961) insula, Aomori Prefecture, Northeast Honshu, Japan. Kai, Mus. Res. Bull. 30: 18 - 38; 4 plts; 1 text fig. Hopkins, Davin Moopy 1967. Quaternary marine transgressions in Alaska. In: D. M. Hopxins (ed.), The Bering Land Bridge. Stanford, Calif.: 47 - 90; 5 text figs.; 2 tables 1972. | The paleogeographic and climatic history of Beringia. Inter- nord 12: 121 - 150; 10 text figs.; 1 table ILtyina, AGNrvA PETROVNA 1939. Fauna gastropod iz Tretichnykh otlozhenii zapadnovo poberezh’ ya Kamchatki [Gastropods from Te=-tiary deposits of the west coast of Kamchatka]. Trudy Neft. Geol.-Razved. Inst., (A), (124): 1-90; 15 plts. (in Russian, English summary) 1954. Molliuski Neogenovykh otlozhenii yuzhovo Sakhalina [Mollusks in Neogene deposits of south Sakhalin] in: L. V. KrIiSHTOFOVICH & A. PR. Iryina, Molliuski Tretichnykh otlozhenii yuzhnogo Sakhalina [Mollusks in Tertiary deposits of south Sakhalin]. Trudy Vses. Neft. Nauch.-Issled. Geol.-Razved. Inst. (VNIGRI), Spets. ser. 10 (222): 188 - 253; 30 plts. [2nd group] 1963. -Molliuski Neogena Kamchatki [Neogene mollusks of Kamchatka]. Trudy VNIGRI 202: 1 - 2413 54 plts.; 3 tables Inc.e, James CuHesney, Jr. 1977. Cenozoic paleoclimatic trends, history of the California Current, and Pacific coast marine biostratigraphy. Geol. Soc. Amer., Abstr. with programs 9: 1032 Kanno, SABURO 1960. Paleontology. In: The Tertiary system of the Chichibu Basin, Saitama Prefecture, central Japan, prt. 2. Japan Soc. Promot. Sci., Tokyo: 123 - 396; plts. 31 - 51; 6 text figs.; 6 tables 1971. Tertiary molluscan fauna from the Yakataga District and ad- jacent areas of southern Alaska. Palaeon. Soc. Japan, Spec. Paper no. 16: 1-154; 18 plts.; 20 text figs.; 7 tables (25 December 1971) KHoMENKO, I. P. 1934. Novye dannye postratigrafii Tretichnykh plastov vostochnovo Sak- halina. Stratigrafiya Tretichnykh sloev yugo-vostochnogo poberezh’ya poluostrova Shmidta (sev. Sakhalin) [New data on the stratigraphy of Tertiary beds of eastern Sakhalin. Stratigraphy of Tertiary beds of the southwestern coast of the Shmidt Peninsula (north Sakhalin)]. Trudy Neft. Geol.-Razved. Inst., (A), (40): 1-86; 19 plts.; 1 map (in Russian, English summary) 1938. Stratigrafiya Tretichnykh otlozhenii poluostrova Shmidta (sev. Sakhalina) [Stratigraphy of the Tertiary deposits of Shmidt Peninsula (north Sakhalin) ]. Trudy neft. Geol.-Razved. Inst. (A), (103): 1- 78 [80]; 17 plts.; 1 map (in Russian, English summary) Vol. 21; No. 2 Kira, TETsuAki 1959. Coloured illustrations of the shells of Japan. Enlarged and rev. ed. Osaka, Hoikusha: i-ix+1-239; 72 plts. 40 text figs. (in Japanese; title page dated 1961) Koraxka, TAMIO 1959. The Cenozoic Turritellidae of Japan. (2) 31 (2): 1-135; 15 plts. 9 text figs. KrisHToFovicH, LuipMiLA VYACHESLAVOVNA 1954. Molliuski Tretichnykh otlozhenii yuzhnogo Sakhalina (Nizhnie svity) [Mollusks in Tertiary deposits of south Sakhalin (lower suite)]. in: L. V. Krisutorovicu « A. P Iryina, Molliuski Tretichnykh ot- lozhenii yuzhnogo Sakhalina. Trudy Vses. Neft. Nauch.-Issled. Geol.-Razved. Inst. (VNIGRI), Spets. Ser., 10 (222): 5-187; 30 pits. [first group] 1964. Molliuski Tretichnykh otlozhenii Sakhalina [Mollusks of the Terti- ary deposits of Sakhalin]. Trudy VNIGRI 232: 1 - 343; 55 plts.; 2 text figs.; 1 table Kvropa, ToKuBEI 1931. Fossil Mollusca. in Fuyio Homma, Shinano Chubu Chishitsu- shi [Sinanotyubu Tisitusi] [Geology of central Shinano Province]. Part 4. Tokyo, Kokin Shoin Publ. Co. pp. [1 - 92], plts. [1 - 13] (in Japanese) (28 February 1931) Sci. Rept. Tohoku Univ. LINNAEUS, CaRL VON 1758. Classis VI. Vermes III. Testacea. tn: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum charac- teribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Holmiae, Laurentii Salvii, pp. 667 - 788 [facsimile reprint: Trustees of the British Museum (Natural History), 1956) MacNeil, Francis STEARNS 1957- Cenozoic megafossils of northern Alaska. Prof. Paper 294-C: 99-126; plts. 11-17; 1 text fig. 1961. Lituyapecten (new subgenus of Patinopecten) from Alaska and California. U.S. Geol. Surv. Prof. Paper 354-J: 225-237; plts. 35-46 1965. Evolution and distribution of the genus Mya and Tertiary migra- tions of Mollusca. U. S. Geol. Surv. Prof. Paper 483-G: i-iv+ G1 -G51; 11 plts.; 3 text figs. 1973. Arctic and boreal climate at the beginning of the Pleistocene. in: Ktyvosu1 AsANo & Nosu Kitamura, eds., Professor Kotora Hatai memorial volume. Tohoku Daigaku, Sci. Rept. 2nd Ser. (Geol.), spec. vol. 6: 55-57 Martin, Bruce 1914. Descriptions of new species of fossil Mollusca from the later marine Neogene of California. Univ. Calif. Publ. Bull. Dept. Geol. 8: 181-202; plts. 19-22 (6 August 1914) MerRIAM, CHARLES WARREN 1941. Fossil turritellas from the Pacific coast region of North Ameri- ca. Univ. Calif. Publ. Bull. Dept. Geol. Sci. 26 (1): v+1- 213; 14 plts.; 19 text figs.; 2 maps (8 March 1941) Nacao, TAKuUMI 1928. Palaeogene fossils of the Island of Kyasha, Japan. Part IT. Sci. Rept. Tohoku Imp. Univ., 2nd Ser. (Geol.) 12: 11 [1] - 140 [130]; 17 plts.; 1 table (30 August 1928) Netson, Ciirrorp MELVIN 1973. The marine gastropod Neptunea in the late Cenozoic. Geol. Soc. Amer., Abstr. with programs 5: 85 1974. Evolution of the late Cenozoic gastropod Neptunea (Gastropoda: Buccinacea). xi+802 pp.; 66 plts.; 17 text figs.; appendix A, B (unpubl. Ph. D. thesis, Univ. Calif, Berkeley) 1976. The type-species of Neptunea Roding, 1798 (Gastropoda: Buc- cinacea). The Nautilus 90 (4): 139-141 (29 October 1976) 1977. The gastropod Neptunea (Prosobranchia: Buccinacea) in the North Pacific Neogene. in TsuNeMASA Saito & Hirosui Uyjne, eds. Proc. First Internat. Congr. Pacif. Neogene Stratigraphy, Tokyo, 1976. Tokyo, Sci. Council Japan and Geol. Soc. Japan: 374-376 (July 1977) Nopa, HirosuHi 1962. Geology and paleontology of the environs of Matsunoyama, Niigata Prefecture, with reference to the so-called black shale. Sci. Rept. Tohoku Univ., 2d Ser. (Gcol.) 34: 199 - 236; plt. 16 (5 December 1962) U. S. Geol. Surv. Nomura, SITIHEI 1937. On some Neogene fossils from along the upper course of Nikko- gawa, Akumi-gun, Yamagata-ken, northeast Honsyf, Japan. Saito Ho-on Kai Mus. Res. Bull. 13: 173-177; plt. 24 (25 August 1937) Oc.e, BuRDETTE ADRIAN 1953. Geology of Eel River Valley area, Humboldt County, California. Calif. Dept. Nat. Res., Div. Mines Bull. 164: 1-128; 6 plts.; 15 text figs. (November 1953) THE VELIGER Page 215 Ortuxka, YANOSUKE 1935. Stratigraphy of the northeastern part of the Oti Graben, Isikawa Prefecture. Journ. Geol. Soc. Japan 42: 483-510; plt. 14; 3 text figs.; 6 tables (20 August 1935) Oyama, Katura 1958. Review of nomenclature on Japanese shells (1). Venus, Japan. Journ. Malacol. 20: 109-114 (in Japanese, English summary) Oyama, Karura, Arsuyuki Mizuno a Toru SAKAMOTO 1960. Illustrated handbook of Japanese Paleogene mollusks. Geol. Surv. Japan [Tokyo, Dai-Nippon Printing Co., Ltd.]: 1 - 244; 71 plts.; 3 text figs.; 7 tables Pearce, Jack B. » GUNNAR THORSON 1967. The feeding and reproductive biology of the red whelk, Neptunea antiqua (L.) (Gastropoda, Prosobranchia) . Ophelia 4: 277 - 314; 15 text figs. Petrov, Ovec MIKHAILovicH & IDA MIKHAILOVNA KHOREVA 1968. Korrelyatsi pozdneneogenovykh i Chetvertichnykh otlozheniy krainevo severo-vostoka SSSR i Alyaski ... [Correlation of upper Neo- gene and Quaternary deposits of the extreme northeast of the USSR and Alaska based on the marine fauna of mollusks and foraminifers). in Granitsa Tretichnogo i Chetvertichnogo Periodov [Boundary of Ter- tiary and Quaternary Periods]. Mezhdunarod. Geol. Kongr. 2374 Sess., Dokl. Sovetsk. Geol. (10), Izd.-vo, “Nauka”: 70-74; 1 table Puiuipr1, RupotF AMANDUS 1850. Abbildungen und Beschreibungen neuer oder wenig gekannter Conchylien unter Mithiilfe mehrerer deutscher Conchyliologen. Cassel, Theodor Fischer 1 [4-7]: Fusus Tab. V, 115 [21]-120 [26] [September 1850; collation, Catalogue books British Museum (Natural History), 4: 1565 (1913)] Pirssry, Henry Aucustus 1901. New Mollusca from Japan, the Loo Choo Islands, Formosa and the Philippines. Proc. Acad. Nat. Sci. Philadelphia 53: 139-210 (6 May 1gor) PLAFKER, GEORGE 1971. Possible future petroleum resources in the Pacific-margin Tertiary basin, Alaska. In: I. H. Cram, ed. Future petroleum provinces of the United States — their geology and potential. Amer. Assoc. Petrol. Geol. Mem. 15: 120-136; 4 text figs.; 1 table Ropinc, PETER FRIEDRICH 1798. Museum Boltenianum sive catalogus cimeliorum e tribus regnis Naturae quae olim collegerat Joa. Fried. Bolten... Pars secunda con- tinens conchylia sive testacea univalvia, bivalvia + multivalvia. Hamburgi, Johan Christi Trappii: i-viit1-199 (post-10 September, 1798; facsimile repr. by Charles Davies Sherborn & Ernest Ruthven Sykes, March 1906) Satin, Yurn SERGEEVICH 1972. Kolichestvennye metody v paleoekologii i biostratigrafi (na primere Neogenovoy Ust’ Kamchatksoy [Quantitative methods in paleoecology and biostratigraphy (on the example of the Neogenian Ust-Kamchatka series) ]. Akad. Nauk SSSR, Sibirsk. Otdel., Inst. Geol. i Geofiz., Trudy, 161: 1-123; 19 text figs.; 15 tables SINEL’NIKOVA, VALENTINA NIKOLAEVNA 1969. Pliotsen zapadnoi Kamchatki [Pliocene of western Kamchatka] in A. V. Fursenxo, (ed.) Biostratigrafiya, fauna i flora Kainozoia severo-zapadnoi chasti Tikhookeanskogo podvizhnogo poyasa [Cenozoic biostratigraphy, fauna and flora from the northwestern part of the Pacific mobile belt]. Moskva, “Nauka,”: 63-65; 1 table SINEL’NIKOVA, VALENTINA NIKOLAEVNA #& Yurn G. DrusHcHITs 1971. Biostratigrafiya Kavranskikh i Enemtenskikh otlozheniy zap- adnoi Kamchatki (Miotsen-Pliotsen) [Biostratigraphy of the Kavranian and Enemtenian sediments of western Kamchatka (Miocene-Plio- cene) ]. Izvest. Akad. Nauk SSSR, Ser. Geol. 1971 (5): 101 - 109; 3 text figs. STRAUCH, FRIEDRICH 1972. Phylogenese, Adaptation und Migration einiger nordischer ma- riner Molluskengenera (Neptunea, Panomya, Cyrtodaria und Mya). Abhandl. Senckenberg. Naturforsch. Gesell. 531: 1-211; 11 plts; 29 text figs.; 2 tables (abstract in English) (November 1972) SWAINSON, WILLIAM 1840. A treatise on malacology, or the natural classification of shells and shell-fish. London, Longman, Orme, Brown, Green, & Longmans . and John Taylor, i- vilit 1-419; 130 text figs. (pre-June 1840) Toco, YosHIRO 1974. Shell structure and growth of protoconch and teleoconch in Neptunea (Gastropoda). Journ. Geol. Soc. Japan 80 (8): 369 - 380; 4 plts.; 7 text figs. (in Japanese, English abstract) (August 1974) Page 216 THE VELIGER Vol. 21; No. 2 Late Neogene Succession of Molluscan Fauna on the Pacific Coast of Southwestern Japan, with Reference to Planktonic Faunal Sequence RYUICHI TSUCHI anp MASAKO IBARAKI Shizuoka University, Japan (6 Text figures) INTRODUCTION THE Paciric coast of southwestern Japan is dotted with late Neogene marine sediments in several areas, as seen in the Kakegawa district west of Shizuoka, the Tonohama district in south Shikoku, the Miyazaki district in east Kyushu, and the Okinawa and Miyako districts in the Southwestern Islands (Ryukyu Islands) (Figure 1). Of these, the Kakegawa district is one of the type areas of the Japanese Neogene where deposits are extensive and continuous, consisting of early and late Neogene series. The late Neogene series, ranging in age from late Miocene to early Pleistocene, is composed of open coastal sediments, with frequent pyroclastic intercalations, some of which have been dated by the fission track method. Mollusks are especially abundant in coarse and shallow sediments in the north, that is, a paleogeographically nearshore area; how- ever, rich planktonic foraminifera are contained in finer and deeper sediments to the south, that is, the offshore area at that time. Pyroclastic layers intercalated in the near- shore facies are useful for the chronostratigraphic sub- division. Biostratigraphically, the series has been divided into several stages by means of the molluscan faunal suc- cession. As a result of our recent field survey, some important pyroclastic layers were found to extend southward into the offshore facies. Paleomagnetic surveys have also been made. It is now possible, therefore, to correlate the molluscan faunal succession in the northern section with the plank- tonic foraminiferal sequence in the southern section. In this paper, the authors would like to demonstrate the inter- relationship between molluscan stages and worldwide * Geoscience Institute, Faculty of Science, Shizuoka University, Shizuoka 422, Japan planktonic foraminiferal zones in the late Neogene sec- tions of the Kakegawa district. GEOLOGY or THE LATE NEOGENE SERIES As the geology and stratigraphy of the late Neogene series in the Kakegawa district have already been elucidated (Tsucut, 1961, 1969, 1976), an outline is given here. The 126°E 38°N+ 26°N + ® MIYAKO oad 20k Figure 1 Distribution of late Neogene sediments on the Pacific coast of southwestern Japan, and index map of the Kakegawa district | WAATY OAUNGL = N aS nn [op) SOM AS SAGARA 000 000 10 II SURUGA BAY Cais Vol. 21; No. 2 iid bon Midd Star THE VELIGER = GAT Dipsgtta sas ss Page 217 | —— SE THIS SO?. 5 YUZANJIAN s fe) wn KECHIENJIAN [-¥) =) re) (4 EF ae A SUCHIAN S > x < 2) [23 v < ry) TOTOMIAN I c (-¥) 5 YUIAN i) i) - ) < n [stacE] Figure 3 Idealized profile of the late Neogene series of the Kakegawa district 1: Pleistocene Ogasayama Gravels. 2: Pyroclastic layer. O8 Figure 2 Geological map of the late Neogene series of the Kakegawa district The map shows the horizontal section so as to clarify the structure. 1: Pleistocene Ogasayama Gravels. 2: Lines are drawn in every 100m in thickness of the strata and parallel to the strike. The dip is given always on the left hand by the arrow. 3: Ap- proximate location and horizon of main fossil localities. 4: Pyro- clastic layer. 5: Silt. 6: Silty sand. 7: Sand. 8: Allter- nation of sand and silt. 9: Angular or subangular pebbles or boulders. 10: Rounded or subrounded pebbles. 11: Early Neogene series and pre-Neogene complex. Silty sand. 7: Angular or subangular pebbles or boulders, subrounded pebbles. complex. — Symbols 1 to 9 and A to M as in Figure 2. 4: Alternation of sand and silt. 5: Sand. 6: Silt. 8: Rounded or 9: Early Neogene series and pre-Neogene (see foldout) 1: Arigaya Tuff. 2: Shiraiwa Tuff. 3: lozumi Tuff 4: Agehari Tuff. 5: Hosoya Tuff. 6: Nishi-Kakegawa Tuff. 7: Sakuragi Tuff. 8: Kogosho Tuff. 9g: Soga Toff. A: Tokigaya Alternation of Granules, Sand and Silt. B: Sagara Alternation of Sand and Silt. C: Oyori and Tamari Silt. D: Hagima Conglomerate. E: Kiriyama Silt. F: Horinouchi Alternation of Sand and Silt. G: Dainichi Sand. H: Nobe Conglomerate. I: Tenno Silty Sand. J: Hijikta Silt, K: A- burayama Sand. L: Tombe Sand-rich Alternation. M: Soga Group (gravels, sand and silt). [strata] SE Woo o¢ 66 Mi, %y “oo Zip d WaATS AANNSL GAWA Wall why wpe vita \ | | \ GE Sa ZY SAGARA Re 9 x i g | J | SURUGA BAY SEA or ENSHU Vol. 21; No. 2 THE VELIGER Page 217 { fe) YUZANJIAN Ss ie) n KECHIENJIAN =") 2 fe) 5 SUCHIAN < = < ie) (23 < x TOTOMIAN oa SO ENG Diptasiega aa 22D TIA ITE 3 9, Cc Eee) . Nor rr rrr ttre tte itt ta tite 5 pe 5 Gomes oaS ao Goa Sono was eee YUIAN i) Sas eo SB SSS85 es Je : 7 é 0000 [stacE] (LA 9 Figure 3 Idealized profile of the late Neogene series of the Kakegawa district 1: Pleistocene Ogasayama Gravels. 2: Pyroclastic layer. 3: Silty sand. 7: Angular or subangular pebbles or boulders. subrounded pebbles. complex. — Symbols 1 to 9 and A to M as in Figure 2. 4: Alternation of sand and silt. 5: Sand. 6: Silt. 8: Rounded or 9: Early Neogene series and pre-Neogene Figure 2 (see foldout) Geological map of the late Neogene series of the Kakegawa district The map shows the horizontal section so as to clarify the structure. 1: Pleistocene Ogasayama Gravels. 2: Lines are drawn in every 100m in thickness of the strata and parallel to the strike. The dip is given always on the left hand by the arrow. proximate location and horizon of main fossil localities. 4: Pyro- clastic layer. 5: Silt. 6: Silty sand. 7: Sand. 8: Alter- nation of sand and silt. 9: Angular or subangular pebbles or boulders. 10: Rounded or subrounded pebbles. 11: Early Neogene series and pre-Neogene complex. 1: Arigaya Tuff. 2: Shiraiwa Tuff. 3: lorumi Tuff 4: Agehari Tuff. 5: Hosoya Tuff. 6: Nishi-Kakegawa Tuff. 7: Sakuragi Tuff. 8: Kogosho Tuff. : Soga Tuff. A: Tokigaya Alternation of Granules, Sand and Silt. B: Sagara Alternation of Sand and Silt. C: Oyori and Tamari Silt. D: Hagima Conglomerate. E: Kiriyama Silt. F: Horinouchi Alternation of Sand and Silt. G: Dainichi Sand. H: Nobe Conglomerate. I: Tenno Silty Sand. J: Hijikta Silt, K: A- burayama Sand. L: Tombe Sand-rich Alternation. M: Soga Group (gravels, sand and silt). [strata] Page 218 geological map and the stratigraphic sequence in the pro- file are shown in Figures 2 and 3. The late Neogene series, consisting of the Sagara, Kakegawa and Soga Groups, over- lies the early Neogene series with marked unconformity and is covered by the Pleistocene Ogasayama Gravels. The Kakegawa Group lies on the Sagara Group with local un- conformity in the north, and the Soga Group also lies on the Kakegawa Group with local disconformity in the north. Thus, each group reveals a sedimentary cycle with shallow deposits in its basal part and is superposed on the underlying group with an unconformable relation in the north, that is, paleogeographically landward, but in the south, that is, offshore at that time, they represent con- tinuous sedimentation. The Sagara Group, the main extension of which is in the eastern Omaesaki Peninsula, consists of a thick rhythmic alternation of sand and silt (Sagara Alternation) in the lower part, with frequent intercalations of granule beds near the base (Tokigaya Alternation), and a massive ho- mogeneous silt (Oyori Silt) in the upper part. Only the upper silt member extends to the north and northwest, where the silt is found exposed as an inlier (Tamari Silt). The thickness of the group ranges from 1500 m in the south to 400 m or so in the north. The Kakegawa Group shows a remarkable contrast in lithofacies between the eastern and western exposures. In the east, a thick rhythmic alternation of sand and silt (Horinouchi Alternation), and a stratified conglomerate bed (Hagima Conglomerate) are predominant in the lower part and a massive homogeneous silt bed (Hijikata Silt) in the upper part. Such a succession resembles that of the Sagara Group. The Hagima Conglomerate in the east is the basal conglomerate of the Kakegawa Group, but in the north it represents a basal unit of a transgressive overlap- ping of the Horinouchi Alternation onto the basement, where it corresponds in age to approximately the whole Horinouchi Alternation. The conglomerate overlies the Sagara Group with unconformity in the north, while in the south it merely represents a transitional bed between the Sagara and Kakegawa Groups, where the conglomerate grades into alternations of sand and granule beds, or thick sand layers. The Horinouchi Member is a rhythmic alter- nationof sand and silt, which attainsa thickness of 3500m in the depocentre near Kikugawa, but becomes thinner towards the northwest and the southeast. The facies of the Kakegawa Group in the west should probably be called a coastal oscillation facies, as compared with the above-men- tioned flysch-type facies in the east. A complete sedimen- tary cycle is found in the vicinity of Kakegawa in a succession of sand (Dainichi Sand), silty sand (Tenno Silty Sand), silt (Hijikata Silt), silty sand (Tenno Silty Sand), THE VELIGER Vol. 21; No. 2 and sand (Aburayama Sand), in ascending order. It is found also in the western end on the left side of Tenryu River in a succession of conglomerate (Nobe Conglomerate), sand (Dainichi Sand), silty sand (Tenno Silty Sand), and sand (Aburayama Sand), where the Hijikata Silt thins out. The Kakegawa Group accumulated first by geosynclinal sub- sidence of the Kikugawa basin, where the thick flysch- type sequence exists, then, the sea gradually invaded the stable area to the west, where the coastal oscillation facies Is seen. The Soga Group, which overlies the Kakegawa Group with local disconformity in the northwest, consists of a sedimentary cycle with gravels, sand and silt in the north- ern area. In the southern area, however, it consists of mas- sive homogeneous silt which is quite similar to, and continuous with, the Hijikata Silt of the Kakegawa Group. Therefore, the lower boundary in the south is defined for convenience between the uppermost pyroclastic layer of the Kakegawa Group (Kogosho Tuff) and the lowest pyro- clastic layer of the Soga Group (Soga Tuff). Many white-coloured fine-grained acidic tuff layers in - the Kakegawa and Soga Groups are keys to chronostrati- graphic subdivision. Important pyroclastic layers are named in ascending order as follows: Arigaya, Shiraiwa, Iozumi, Nishihirao, Agehari, Hosoya, Nishi-Kakegawa, Sakuragi, Kogosho, and Soga, respectively. As clearly dem- onstrated on the geological map and also in the profile, the time-stratigraphic markers intersect the rock facies divi- sions. Concerning the geologic structure, the Sagara Group exhibits a folded structure with a NE-SW trend in the southeast, where several brachy-anticlines and brachy- synclines are found pari passu. The NE-SW trend of the structure abruptly turns in the north to the E-W trend with a southward dip. The Kakegawa Group displays a monoclinal structure with the NW-SE trend in the east dipping to the southwest at about 15 degrees, where the trend is oblique to that of the underlying Sagara Group, but in the southeastern area, the trend turns gradually to NE-SW, where the structure becomes concordant with that of the Sagara Group. The strong inclination of the Horinouchi Alternation in the southeastern area decreases upward. The Kakegawa Group in the west trends from ESE to WNW showing a homoclinal structure dipping to SSW at about 8 degrees. The structure of the Soga Group is concordant to the Kakegawa Group. Therefore, it is . noteworthy that the local disconformity at the base of the Soga Group indicates a kind of epeirogenic fluctuation, presenting a marked contrast to the local unconformity at the base of the Kakegawa Group which evidently resulted Vol. 21; No. 2 from the crustal movement followed by a shifting of the basin. MOLLUSCAN FAUNAL SUCCESSION The Kakegawa molluscan fauna, studied by YoKoYAMA (1923, 1926), MAKIYAMA (1925, 1927, 1931, 1941b, 1952) and Tsucui (1961, 1969), is known as the best representative of the Pliocene of the Pacific coast of southwestern Japan. The Sagara molluscan fauna is characterized by Amussio- pecten iitomiensis (Otuka), Chlamys miurensis (Yoko- yama), etc. The Kakegawa fauna comprises Amussiopecten praesignis (Yokoyama), Venericardia panda (Yokoyama), Specific name (Recent allied species) Chlamys miurensts (Yokoyama) Amussiopecten titomiensis Mercenaria chitaniana (Yokoyama) (cf. M. stimpsont) Glycymeris nakamurat Makiyama (cf. G. albolineata) Amussiopecten praestgnis (Yokoyama) Suchium suchiense paleosuchtense Tsuchi, MS. (cf. S. giganteum) Venericardta panda (Yokoyama) Turritella perterebra Yokoyoma (cf. T. terebra) Babylonia elata (Yokoyama) (cf. B. formosae) Anadara satowi castellata Makiyama (cf. A. satowt) Glycymeris totomiensis Makiyama Mercenaria yokoyamai Makiyama (cf. M. stimpsoni) Suchium suchiense suchiense (Yokoyama) (cf. S. giganteum) Siphonalia declivis Yokoyama Hindusia magnifica yokoyamai (Tsuchi) (cf. H. magnifica) Turritella perterebra Yokoyama var. (cf. T. terebra) Babylonia elata (Yokoyama) var. (cf. B. japonica) Stphonalia declivis biconica Makiyama Suchium suchiense subsuchtense (Makiyama) (cf. S. giganteum) Glycymeris albolineata (Lischke) Suchium giganteum (Lesson) Hindusta magnifica (Lischke) THE VELIGER Page 219 Suchium suchiense (Yokoyama), Turvitella perterebra (Yokoyama), Siphonalia declivis (Yokoyama) and many other warm current and tropical forms, 50% of which are extinct species. The Soga fauna consists mostly of Recent species which are now living in the adjacent sea. From the viewpoint of chronostratigraphic subdivision, the strati- graphic sequence of the late Neogene series can be divided by molluscan faunal changes into the following five stages in ascending order. 5) Yuzanjian 4) Kechienjian (Soga Group) 3) Suchian (Kakegawa Group) 2) Totomian 1) Yuian (Sagara Group) TOTOMIAN KECHIENJ. YUIAN SUCHIAN yuzany,| RECENT Figure 4 Stratigraphic range chart of important molluscan species and sub- species of the late Neogene series of the Kakegawa district. Page 220 The bases of the Suchian and the Kechienjian are, for convenience, defined by pyroclastic layers just below fossil localities and assigned, respectively, to the basal horizons of the Iozumi Tuff and the Hosoya Tuff. The definitions of the Yuian, Suchian, Kechienjian and Yuzanjian stages which were proposed originally by Mak1yAMA (1931, 1941a), and MAKIYAMA & SAKAMOTO (1957) have been amended by Tsucut (1961). The Totomian Stage was pro- posed by Tsucut (1961). Thus, the Horinouchi Alternation nearly belongs to both the Totomian and Suchian Stages, the Hijikata Silt to both the Kechienjian and Yuzanjian Stages and the Dainichi Sand facies corresponds to both the Suchian and early Kechienjian Stages, i. e., the middle and upper parts of the Kakegawa Group. Vertical ranges of the important molluscan species are shown in Figure 4. The combination of genera or species of one stage is essentially similar to another. This means that similar conditions continued for a long time through- out this sequence of stages. A faunal change between two successive stages means the appearance or disappearance of a species or subspecies, especially by the replacement of a form by an allied one. The major faunal changes are, how- ever, recognized between the stratigraphic cycles. That is to say, the rise and fall of the fauna seem to be inseparable from the sedimentary cycles. Here, the Sagara, Kakegawa and post-K akegawa (living form) faunas which the authors propose are such major faunas. The vertical succession of the faunas in respective stages are as follows: 5) Yuzanjian Stage: The coexistence of the Kakegawa relics with living species which amount to 90% of the fauna. 4) Kechienjian Stage: The disappearance of some Ka- kegawa members and slight modification of some others. 3) Suchian Stage: The acme of the Kakegawa fauna. 2) Totomian Stage: The appearance of a few Kake- gawa members coexisting with Sagara relics. ) Yuian Stage: This is represented by the flourishing of the Sagara fauna. _ The whole fauna of the Kakegawa district has a combi- nation of genera and species that is similar to the present open coastal community on the Pacific coast of southwest- ern Japan. Accordingly, the open coast must have been similarly affected [controlled] by the warm Kuroshio cur- rent in the late Neogene period just as it is today. There- fore, the faunal changes in the succession depend on either minor changes of the environment, or probably, organic evolution. This is well demonstrated by aseries of Suchium suchiense, a typical japonic endemic form, that range from the Totomian stage through the Suchian and Kechienjian THE VELIGER Vol. 21; No. 2 to the Yuzanjian Stage. This series includes S. suchiense paleosuchiense Tsuchi MS. of the Totomian, S. suchiense s.s (Yokoyama), of the Suchian, and S. suchiense subsuchi- ense (Makiyama) of the Kechienjian and Yuzanjian, which are trochid gastropods having spiral striae on the surface, and tubercles on the subsutural band. As the surface fea- tures in the bio-series gradually change from one subspe- cies to another, the series can be considered as a successional species (Tsucut, 1969). Suchium giganteum (Lesson), a living species with a smooth surface with a few feeble striae on the peripheral margin, appeared in the Yuzan- jian; this species flourishes in the later part of the stage. One of the characteristics of the Sagara and Kakegawa faunas is the inclusion of rich tropical elements, which are not found in adjacent seas. For example, recent species allied to Venericardia panda (Yokoyama), Turritella per- terebra (Yokoyama) and Babylonia elata (Yokoyama) are living on the coast south of Formosa. Allied Neogene forms of Amusstopecten occur in Formosa, Timor and Java. Nas- sartus, Hindsia and Babylonia bear canaliculate shoulders and other similar features of allied forms living in tropical seas. These tropical elements abruptly decline in the Kechienjian and all of them disappear by the end of the Kechienjian, when some thermal fluctuations probably oc- curred. PLANKTONIC FORAMINIFERAL BIOSTRATIGRAPHY AND RELATION to MOLLUSCAN STAGES Planktonic foraminiferal biostratigraphy of the late Neo- gene series has been studied by Sarto (1960) and several others. OpA (1971) confirmed that the biostratigraphic clas- sification of the Sagara Group by planktonic foraminifera corresponds well to zones established originally in the trop- ical region by BLow (1969). According to Uyne & Hariu (on facing page —>) Figure 5 Columnar section of the late Neogene series of the Kakegawa district, with reference to vertical ranges of selected molluscan and planktonic foraminiferal species, and magnetostratigraphy. A: Strata. B: Stage. C: Magnetozone. D: Columnar sec- tion (Tuff: Ar-Arigaya; SH -Shiraiwa; Io - Iozumi; Ni - Nishi- hirao; Ho - Hosoya; Ko - Kogosho; So - Soga). E: Coiling of Pul- leniatina complex. F: Vertical range of selected planktonic forami- nifera. G: Planktonic foraminiferal zone. H: Vertical range of selected molluscan species. Nysvoo || NvifNvznA — [NvIfNaIHOax] —_—sNVIHONS 25 | Serene eae ee INVITOLOL | NVINA fa wnajiupsis wniyons asuaiyonsgns *s umiyong “88 asuaiyons wniyong asuaiyonsoajng ssuoiyons wniyong siudisapsg uajzragoissnup [EEE q Sisusiwmoj uajzagoissnup — — = —————__——————— Page 221 SSUNG ee a I a 18'N ce) sayjuaday vussa5iqojg —-------------------------- suaosiyap vuisponboqojs goupsp Dursppnbogojg) vaigsi31D 4145190 Dursponboqo)y Dpiwunjorseyg Dpiwny v17D30L0G0;5) [ard Dpiunjos9us 0170304090] & Lu UO aDjs08 Duk D11D}04090)5) —_—_—_—_______ — = sisuapn3ua] 0170301090]5) Lag Sapiouinjiprunsy 0110101090] 36 ee tS EE eee ee fF sisuapsoj 0110301090) Susoyap DjauipiossDyds Suaosiyapqns suazsiyapans sisdojjaurproszapyg ¢§ —<—$&@@£& @ oo — — Dusnuiwas Durnurmas sisdojjaurprosapy g ¢ —————_______ % Sees 3 Ses Seas Se se Q : >] I 1 I PU ot WE CUTE PPh eh tet be ete Phtrrrde ti TCU ALL Ye a Bsa = z 3 & < a a C 9 on lh = — 3) fo) Nvsvoo__| NvIfNVZNA [NvIfNaIHOax] NVIHOAS =| poe NVIMOLOL [ NVINA --} Zz six “OD VAVAYSVDO; dNOUud V9OS tt dNOUdD VMVOFIVA ee L dNOUD VUAVOVS < ol . ——_______ 4 1 tL, = SS ae a) E i= =] 2 ° ° ° ee : : : Page 222 (1975), the Sagara Group belongs to Zone N.14-N.19 ranging in age from the latest middle Miocene to early Pliocene. In the Kakegawa Group, Zones N.19-N.22 have been recog- nized by Morozum1 (1972) and KaTo (1973). From the view- point of planktonic foraminifera, therefore, the Miocene/ Pliocene and Pliocene/Pleistocene boundaries might be defined in the upper part of the Sagara Group and in the upper part of the Kakegawa Group, respectively. The planktonic foraminiferal biostratigraphy of the dis- trict was also investigated recently by the authors, espe- cially in sections of southern offshore facies (IBARAKI & Tsucnl, 1974, 1976; Tsucui & IBARAKI, 1977a). The relation of the planktonic foraminiferal sequence to the molluscan stages can be clearly ascertained by means of intercalated pyroclastic layers which occur throughout the northern nearshore and southern offshore facies. Magnetostrati- graphic surveys were also made by YosHIDA & NIITSUMA (1976) on the same routes and sections. Results of those investigations are shown in Figure 5, in which vertical ranges of selected planktonic foraminiferal and molluscan species important for zoning are arranged. The first occurrence of Sphaeroidinella dehiscens (Par- ker & Jones) which defines the base of Zone N.19 is recog- nized in the middle of the Sagara Group, or in the middle Yuian Stage. Globorotalia tosaensis Takayanagi & Saito makes its initial evolutionary appearance at a horizon 120m above the base of the Kakegawa Group and a little below the Arigaya Tuff in the basal part of the Kakegawa Group, or in the earliest Totomian. And Globorotalia truncatu- linoides (D’Orbigny) initially appears at a horizon just below the Hosoya Tuff, i.e., nearly at the base of the K echi- enjian. Thus, the bases of Zones N.21 and N.22 are defined, respectively by initial appearances of these species. Based on the successive appearance of Sphaeroidinella dehiscens, Globorotalia tosaensis and G. truncatulinoides, horizons of the later half of the Yuian Stage and the earliest part of the Totomian, those of most of the Totomian and Suchian, and both the Kechienjian and the Yuzanjian are assigned, respectively, to Zones N.19+20, N.21 and N.22. Globo- quadrina asanoi Matya, Saito & Sato ranges from a horizon a little above the initial appearance of Globorotalia tosa- ensis to a horizon a little above the first appearance of G. truncatulinoides, corresponding to horizons from the ear- liest part of the Totomian to the earliest part of the Kechi- enjian. The vertical range of the species has been recog- nized from the middle of the Gauss Normal Epoch to the base of the Olduvai Event in the North Pacific deep sea cores, and the specimens have also been found abundantly in the upper part of the Funakawa Formation of the Oga Peninsula on the Japan Sea coast, being restricted to the Globigerina pachyderma (dextral)/Globorotalia orienta- lis Zone (Marya, Sarto & Sato, 1976).Thus, the species is THE VELIGER Vol. 21; No. 2 important in the correlation of the Neogene of the Pacific coast with that of the Japan Sea coast and North Pacific deep sea sediments. Abrupt changes in coiling direction of the Pulleniatina complex from sinistral to dextral recognized in the late Yuian, from dextral to sinistral in the early Suchian, and from sinistral to dextral at the beginning of the Yuzanjian are noticeable. Partial changes of the coiling ratio are found in a horizon following the abrupt change from dex- tral to sinistral in the early Suchian, and also in two hori- zons of the late Suchian and late Kechienjian. The magnetozones recognized in the Kakegawa Group can be correlated with magnetic polarity intervals estab- lished in deep sea sediments (OppykeE e¢ al., 1974), by con- sidering the interrelation between the biostratigraphy and magnetostratigraphy of deep sea cores (Hays et al., 1969). A normally magnetized interval found in horizons below the middle Totomian can be correlated with the Magnetic Interval 3 or “Gauss Normal Epoch,’ a predominantly re- versed magnetized interval in horizons above the middle Totomian with the Magnetic Interval 2 or ‘““Matuyama Re- versed Epoch,’ and a predominantly normally magnetized interval of the early Kechienjian with the Subinterval 2-b or ‘“Olduvai Normal Event:’ The initial appearance of Globorotalta tosaensis in the Gauss Normal Epoch, and of G. truncatulinoides in the basal part of the Olduvai Nor- mal Event, and the aspect of coiling changes of Pullenia- tina correspond well to the record in equatorial Pacific deep sea cores (Hays et al., 1969). The Neogene-Quaternary boundary might be placed, at present, at or near the base of the Kechienjian Stage (IKEBE & TsuculI, 1977; TsuCHI & IBARAKI, 1977b). From the ratio of tropical and subarctic species to the total population, the temperature of the seawater during the Kakegawa Age might not be very different from that of the present adjacent sea, but a cooling of seawater tem- perature since the latest Kechienjian is suggested. This fact seems to match well with the disappearance of tropical mollusks by the end of the Kechienjian. Radiometric age determinations by the fission track method have been attempted on some pyroclastic layers of the Kakegawa Group. The Arigaya, Iozumi and Ho- soya Tuff beds have been dated, respectively, at 5.8X10° y. B. P, 2.8X10° y. B. PR and 2.2X10° y. B. P (NisHimuRA, 1975). According to Dr. S. Nishimura of Kyoto Univer- sity (oral communication), however, the above-mentioned datings may change to younger values based on recent re-examination. From the magnetostratigraphy and radi- ometric ages, an estimation of the evolutionary rate of speciation in Suchium and some other Mollusca and planktonic foraminifera can be made. Vol. 21; No. 2 THE VELIGER Page 223 As the chronostratigraphic subdivision of the late Neo- gene series of the Kakegawa district can be discriminated through late Neogene sections on the Pacific coast of south- western Japan, the above-mentioned interrelation between molluscan stages and planktonic foraminiferal zones seems to be applicable throughout the region. A correlation chart of late Neogene sediments on the Pacific coast of south- western Japan is shown in Figure 6. The planktonic fora- miniferal sequence and its relation to molluscan stages have been ascertained by the authors in a section in the southern Okinawa Island (IBARAKI & TsucuI, 1975). SUMMARY Study of the late Neogene molluscan faunal succession in nearshore sections and the planktonic foraminiferal se- quence in offshore sections of the Kakegawa district has demonstrated the interrelationship between molluscan . a i- +) cy Ss) 3 eases s 2 % 3S = a eg 3 gated > Md es s<2 Ses $ ES :& Bess v4 © Ss G&S Eos $3 a fe) Sa 2S wBySs 3 x tx a5 Buide Be ie) a s 3 5 2 3 i Oy 2 = N 2 2 22a 3 = 2b G i=] 6 : 6 re 3 é N a & oo io Figure 2 Percent composition of pelagic cephalopods in the SAMMP mid- water trawl catches; N = 63 samples young are represented and exact populational abundances are not known due to probable net avoidance of larger in- dividuals, especially during the day. Vol. 21; No. 2 THE VELIGER Page 257 SEPIOIDEA SEPIOLIDAE Rossia pacifica Berry, 1911 The common benthic sepiolid, Rossva pacifica often is taken in bottom trawls between about 40 and 250m in the bay. Over twenty specimens have been taken by MLML in recent years and it appears to be absent over coarse sand, preferring instead muddy bottoms. TEUTHOIDEA LOLIGINDAE Loligo opalescens Berry, 1911 Loligo opalescens is the only commercially fished cephalo- pod in Monterey Bay today; over 7,000 tons were landed at the bay’s 3 ports in 1974 (MCALLISTER, 1976). Fishing grounds stretch from south of the Salinas River to west of Monterey in depths of about 20 to 50m. This is also the chief spawning area for the species. FIELDs (1965) detailed the general biology of L. opalescens and a recent sympo- sium held at the annual California Cooperative Oceanic Fisheries Investigations (CalCOFI) meetings has updated our knowledge of this cephalopod, the results of which are to be published in the CalCOFI Reports. The reader is referred to this publication for most of the literature on L. opalescens. ENOPLOTEUTHIDAE Abraliopsis felis McGowan « Okutani, 1968 Only eight specimens of A braliopsis felis (8-38 mm DML), a relatively abundant offshore squid (OKkUTANI & Mc- Gowan, 1969), were taken during the SAMMP program inside the bay. It is one of the most frequently encountered prey species of albacore caught off central California, but its appearance in Monterey Bay probably is occasional. Because of changes in length frequencies, PEARCY (1965) suggested the species may be a seasonal breeder in near- shore waters off Oregon during the summer. OMMASTREPHIDAE Dosidicus gigas d’Orbigny, 1835 The jumbo squid, Dosidicus gigas, enters Monterey Bay infrequently (BARTSCH, 1935; CLARK & PHILLIPS, 1936; CROKER, 1937; PHILLIPS, 1933). Clark and Phillips listed the northernmost capture locality for this species as 20 miles north of Santa Cruz, which apparently is still valid. Known to attain 1.4m DML off Peru (see WorMmuTH, 1974), Monterey Bay specimens have generally measured less than about 350mm DML (CLrarK & PHILLIPs, 1936; personal observations of five specimens taken in 1974 and 1976). HIsTIOTEUTHIDAE Histioteuthis heteropsis (Berry, 1913) Although infrequently encountered above 500 m in Mon- terey Bay, ten specimens of Histioteuthis heteropsis (12- 128mm DML) have been captured recently. Five mid- water trawl collections were below 400 m during the day, one in 300 m at night captured two specimens. One speci- men (76mm DML) was found dead on the beach in front of MLML after strong winds in March, 1975. Generally voracious in the aquarium, specimens have lived a maxi- mum of four days at 7°C (McCoskErR & ANDERSON, 1976). OcTOPOTEUTHIDAE Octopoteuthis deletron Young, 1972 Two specimens of Octopoteuthis deletron (24, 102mm DML) were taken in the closing midwater trawl at 190 and 500m, both during the day. In addition to these, 1 specimen was identified from the stomach of the slope- dwelling fish Antimora microlepsis captured in a beam trawl in 1390m, suggesting the squid was swimming close to the sea floor. The fish is not known to swim far off the bottom in search of prey. GoNATIDAE Berryteuthis anonychus (Pearcy & Voss, 1963) The Gonatidae are one of the most abundant oegopsid squid families in California waters. Two specimens of Berryteuthis anonychus (26, 72 mm DML) were captured in the midwater trawl fished between 400 and 500m at night. This record adds another gonatid to these waters and extends the known range of B. anonychus southward from Oregon, the only other reported capture locality (PEARCY & Voss, 1963; YOUNG, 1972). Gonatus californiensis Young, 1972 Published eastern North Pacific ranges of Gonatus spe- cies are from northern Baja California to off Oregon Page 258 (YouNG, 1972; Pearcy et al., 1977). A single specimen of Gonatus californiensis (15mm DML) was taken in the same haul as the Berrytewthis specimens, and represents the northernmost record for this species. Also, a single Gonatus berry: Naef, 1923 specimen of Gonatus berryi (20mm DML) was taken in the midwater trawl between 400 and 500m at night. An- other G. berryi was taken in a zooplankton tow fished to 200m at night but subsequently was lost. Gonatus onyx Young, 1972 Larval and juvenile Gonatus onyx were the most abun- dant pelagic cephalopod taken in midwater trawls in Mon- terey Bay (72 specimens, 8-53 mm DML). An upward shift at night for these young was evident (Figure 3). Three spec- Be (0; 7) re (6, 2) 2 as day night |(9, 3) E Fi (9, 3) 3 (10, 3) 500 - as (3, 1) vo (2, 1) aah (2, 2) © 0.03 0.06 0 0.03 0.06 catch, no. /hr. Figure 3 Vertical distribution of Gonatus onyx in Monterey Canyon. Catch per effort mirrored. Numbers in parentheses on right are sample sizes in each 100m interval, day first, then night imens (42-45 mm DML) were dip-netted at the surface one night. Although hauls below 500 m were scarce, an increase in number occurred around 600 to 700 m during the day, possibly due toa near-bottom concentration of nekton and plankton noted for some fish and crustaceans as well (An- DERSON, 1977). ROPER & YOUNG (1975), by using a correc- tion factor to compensate for unequal trawling time at depth, show the daytime center of abundance of the species in southern California waters to be around 600 m. PEARCY et al. (1977), however, show a daytime center at about 300 THE VELIGER Vol. 21; No. 2 m off Oregon with small individuals clustered in the upper 100m. Lu & CLARKE (1975) suggest a pattern of ontoge- netic descent (larvae descend as they grow) in G. fabricii which, if applied to G. onyx in Monterey Bay, would mean the proposed vertical migration in this species is a com- pounded result of different distributional patterns. Gonatopsis borealis Sasaki, 1923 Two young Gonatopsis borealis (22, 26mm DML), a species ranging from California to the Bering Sea and Japan, were taken in the same midwater trawl haul as the Berryteuthis specimens in 400 to 500 m at night. In addi- tion, two large adults (229, 185 mm DML) were taken ina commercial trawl operated by the National Marine Fish- eries Service off Santa Cruz in August, 1976. This daytime collection in nearshore waters of 220 to 250 m depth prob- ably is unusual, unless adults occupy shallower water than juveniles. Pearcy et al. (1977) found the daytime distri- bution of young Gonatopsis in oceanic waters off Oregon to be between 200 and 600 m. Similarly, RopER « YOUNG (1975) found the daytime center of distribution off south- ern California to be about 400 to 600 m for this species. ONYCHOTEUTHIDAE Moroteuthis robustus Verrill, 1876 Five records of the giant squid, Moroteuthis robusta, exist from Monterey Bay (BERRY, 1912b, 1914; PHILLIPS, 1933, 1961; SMITH, 1963). HOCHBERG (1974) reported some re- cent captures from southern California and SMITH (1963) and TALMADGE (1967) have reported captures from north- ern California. One larval specimen (26mm DML) that is tentatively referred to this species (R. E. Young, pers. comm.) was taken in the midwater trawl fished at night in 400 to 500m. Additionally, an immature female 710mm DML) was found floating dead at the surface by MLML divers about one mile off Moss Landing. Apparently, the species is abundant in about 200 to 4oom, particularly during the fall. Onychoteuthis borealijaponicus Okada, 1927 Onychoteuthis borealijaponicus is represented in the collection by four larvae (9-16 mm DML) taken at night in 400 to 500m. Adults periodically are common at the sur- face just outside the bay and often are taken by local fisher- men for bait. Vol. 21; No. 2 CHIROTEUTHIDAE Chiroteuthis calyx Young, 1972 Six specimens of Chiroteuthis calyx (26-52 mm DML) were taken in the midwater trawl fished between gooand 700m. Other cruises have yielded additional specimens bringing the present total to 21, and the species apparently is abun- dant year-round. All specimens are “‘doratopsis” larvae or young juveniles less than’ 70mm DML. One larva (31 mm DML) was dip-netted at the surface at night. Valbyteuthis danae Joubin, 1931 A single specimen of Valbyteuthis danae (55 mm DML) was caught in the midwater trawl at night in 400 to 500m. Younc (1972) also reported a single specimen from off southern California and concluded his specimen was a straggler from a more tropical population, since previously it was known only from Panama and Peru. CLARKE & Lu (1974) suggested ontogenetic descent in this species, and indeed YounG (1972) described it as one of the deepest living cephalopods off southern California. This second California specimen suggests the species is more widely dis- tributed than current data indicate. CRANCHIDAE Galiteuthis phyllura Berry, 1911 Larval and juvenile Galiteuthis phyllura were the second most abundant cephalopod sampled by midwater trawl (36 specimens, 6-68 mm DML). A slight upward shift at night was detected for these specimens and the species was absent from the upper 100 m (Figure 4). RopER & YOUNG (1975) day night 0 0.015 0.03 catch, no./hr. © 0.015 0.03 Figure 4 Vertical distribution of Galiteuthis phyllura in Monterey Canyon. Graphics after Figure 3 THE VELIGER Page 259 show ontogenetic descent in larval Galiteuthis. Only five specimens larger than 60mm DML (larval development complete) were taken in the bay and these were from night tows between 300 and 600 m. VAMPYROMORPHA VAMPYROTEUTHIDAE Vampyroteuthis infernalis Chun, 1903 A single young specimen of the vampire squid, Vampyro- teuthis infernalis (1gmm DML) was taken in an open midwater trawl that fished to 1000 m by personnel of Hop- kins Marine Station, Pacific Grove. An inhabitant of great depths, it is likely that more specimens will be taken in the bay as deeper hauls are made, since it is considered a world- wide species (PICKFORD, 1946). PHILLIPS (1934) reported a specimen of Cirroteuthis ma- crope Berry, 1911 from the bay but this nominal species should be referred to the synonymy of Vampyroteuthis in- fernalis Chun, 1903 (YOUNG, 1972). It is not known if Phillips’ specimen was a vampire squid or a cirrate octo- pod such as Opisthoteuthis californiana which it resem- bles. The specimen could not be found and may not have been preserved. OCTOPODA BOLITAENIDAE Japetella heath: (Berry, 1911) Two young specimens of Japetella heathi (13, 27mm DML) were taken by the closing trawl in daytime tows be- tween 300 and 600m. Two other specimens (17, 21mm DML) were taken in open nets fished to over 500m dur- ing the day. YouNG (1972) indicated some taxonomic con- fusion exists in Japetella and the Monterey Bay specimens have been tentatively identified to J. heathi due to the pres- ence of silvery tissue around the eyes. ARGONAUTIDAE Argonauta pacifica Dall, 1872 The tropical-subtropical paper nautilus, Argonauta pa- cifica has been found off California, apparently more often during warm water years of the nineteenth century. DALL (1872: 95) first reported it, “‘so common at certain periods on the coast of California . .:’ and later listed it from Mon- Page 260 terey Bay (DALL, 1908). Apparently, it has not been col- lected subsequently in the bay. OcTOPODIDAE Graneledone sp. Four specimens of the slope-dwelling octopod, Granele- done sp., recently were taken off Monterey Bay. One, from a commercial sablefish trap set in 1165 m, measured 156 mm DML. Three others (100, 108, 121 mm DML) were taken in a beam trawl at depths of 1336 to 1409 m. During Benthoctopus sp. the same cruises, 4 specimens of Benthoctopus sp. (34, 35, 41,50mm DML) were caught in hauls made between 1336 and 1609 m. Neither species has been positively identified and they may be new to science (W. G. Pearcy, pers. comm.). Octopus californicus Berry, 1911 ? Octopus doflein: (Wilker 1910) Octopus leioderma Berry, 1913 Octopus pricei Berry, 1913 Octopus rubescens Berry, 1953 Three species of Octopus are known to me from recent collections in the bay: O. rubescens, O. dofleini and O. leio- derma. BERRY (1911, 19124) listed a young O. californicus from deep water off Monterey Bay but cautioned that its identity was not certain. Octopus pricei was described from Monterey Bay (BERRY, 1913), but no individuals positively referable to this species have been identified recently. O. rubescens is the commonest intertidal-subtidal octopod in Monterey Bay (see WARREN et al., 1974; BALLERING et al., 1972) and it has been taken to a depth of 267 m. Below that depth O. californicus should occur, but collections from the canyon at depths greater than 200 m are few and speci- mens have not been obtained as yet. PHILLIPS (1934) re- ported Polypus hongkongensis as the common subtidal octopod that composed most of the California fishery. Pick- FORD (1964), however, showed P. hongkongensis Berry, 1911 to be a synonym of Octopus dofleini (Wiilker, 1910), a widely distributed, variable species. Additionally, a re- cent otter trawl collection in the bay yielded 2 specimens of Octopus leioderma (45, 55mm DML) from 110 to 149 m depth. THE VELIGER Vol. 21; No. 2 OPISTOTEUTHIDAE Opisthoteuthis californiana Berry, 1949 A single, bright orange juvenile of the benthopelagic octo- pod Opisthoteuthis californiana (21 mm DML) was taken in the midwater trawl at a depth of 350 to 460 m (between 120 and 260m above the bottom) during the day. This specimen lived for 5 days in the Steinhart Aquarium cold water tank at MLML (see McCoskErR & ANDERSON, 1976). The octopod exhibited positive phototaxis (in dull light) and swam in short bursts by rapidly pulsing its webbed arms, augmented by siphonal jet propulsion. The fins were flapped alternately to maintain a vertical position in the water column in the manner reported by PEREYRA (1965). DISCUSSION Although the collection of pelagic cephalopods reported here lacks a total size range for all species and, in fact, rep- resents only a few specimens of each, it is the largest series of its kind collected so far from Monterey Bay. To empha- size the prior lack of knowledge of cephalopods from this area, it should be noted that a single haul of the Tucker trawl one night yielded 5 species never reported before from the bay. To examine seasonal variation in the pelagic cephalo- pod catch, numbers of species and individuals of ceph- alopods were compared to numbers of species and vol- umes of all micronekton (fishes, shrimp and squid) and plotted against time. The result was that cephalopod abun- dance remained almost constant due to the numerical dom- inance of Gonatus onyx and Galiteuthis phyllura. A one way analysis of variance with unequal sample size (SOKAL & ROHLF, 1969) showed that variability in micronekton volumes was so high within seasonal categories that differ- ences were not statistically detectable. This was thought to be due to small sample size, variability in depths sampled and the rather weakly defined hydrographic seasons in Monterey Bay during the trawling (BROENKOow et al.,1975, 1976). However, PEarcy (1976) recorded an increase of nekton and plankton in the winter in nearshore areas off Oregon. Similarly, Fast (1960) showed a winter “invasion” of juve- nile lanternfish, Stenobrachius leucopsarus in Monterey Bay and hypothesized that at this time of year the canyon may act as a concentrating basin in conjunction with the nearshore component of the northward flowing Davidson Vol. 21; No. 2 THE VELIGER Page 261 Current. At this time, the effect of nearshore submarine canyons on the concentration of nekton and plankton is unproven and clearly more study is needed in this area. ACKNOWLEDGMENTS I would like to thank F. G. Hochberg, J. W. Nybakken, R. E. Young and W.G. Pearcy for criticisms of earlier drafts of this paper; Drs. Hochberg and Young also helped with identification of specimens. The midwater trawling program was supported by a grant from the Charline Bree- den Foundation, John E. McCosker, principal investiga- tor. Several fellow graduate students and faculty of the Moss Landing Marine Laboratories helped collect and an- alyze the samples, particularly Brooke S. Antrim, Gary R. McDonald, Gregor M. Cailliet, Edwin K. Osada, Donald E. Baltz and James W. Nybakken. Literature Cited ANDERSON, M. E. 1977. Systematics and natural history of the midwater fish Lycodapus mandibularis Gilbert in Calfornia waters. Unpubl. thesis, Calif. State Univ. Hayward, 89 pp. Baxer, A. ve C., M. R. Crarxe & M. J. Harris 1973. The N.I.O. combination net (RMT 1+8) and further devel- opment of rectangular midwater trawls. Journ. Mar. Biol. Assoc. U.K. 53: 167 - 184 Baruerina, R. B., M. A. Jarvino, D. A. Ven Tresca, L. E. HALLAcHER, J. T. Tomuinson e« D. R. WosBer 1972. Octopus envenomation through a plastic bag via a salivary proboscis. Toxicon 10: 245 - 248 Bartscu, PAUL 1935. An invasion of Monterey Bay by squids. (3): 107-108 Berry, SAMUEL STILLMAN Igit. Preliminary notices of some new Pacific cephalopods. Proc. U.S. Nat. Mus. 40 (1838): 589 - 592 (31 May 1911) 1912a. A review of the cephalopods of western North America. Bull. U. S. Bur. Fish. 30 (for 1910), Doc. 761: 267 - 336; plts. 32-36; 18 text figs. (24 July 1912) 1g12b. Note on the occurrence of a giant squid off the California coast. The Nautilus 25 (10): 117-118 (15 February 1912) 1913a. Notes on some west American cephalopods. Proc. Acad. Nat. Sci. Philadelphia 65: 72-77; 2 text figs. (February 1912) 1914. Another giant squid in Monterey Bay. The Nautilus 28 (2): The Nautilus 48 (19 January 1935) 22-23 (13 June 1914) Broznxow, W. W, S. R. Lastey « G. C. ScHRADER 1975. California Cooperative Oceanic Fisheries Investigations hydro- graphic data report Monterey Bay, July to December 1974. Moss Landing Mar. Lab. tech. rept. 75-1: 1 - 80 1976. Cal COFI Monterey Bay, January to December 1975. Moss Landing Mar. Lab. tech. reprt. 76-1: 1 - 80 Crark, EN. « J. B. Paiups 1936. Commercial use of the Jumbo squid, Dosidicus gigas. Calif. Fish & Game 22 (2): 143-144 Crarke, M. R. « C. C. Lu 1974. Vertical distribution of cephalopods at 30° N 23° W in the North Atlantic. Journ. Mar. Biol. Assoc. U.K. 54: 969 - 984 Crassic, R. FE 1929. Monterey squid fishery. Calif. Fish & Game 15 (4): 317-320 1949. Squid. in: Bureau of Marine Fisheries (ed.). The commercial fish catch of California for the year 1947, with an historical review 1916-1947. Calif. Fish & Game, Fish Bull. 74: 1 - 267 Croxer, R. S. 1937. Further notes on the jumbo squid, Dosidicus gigas. Calif. Fish & Game 2g (3): 246 - 247 Dat, Wittiam Hearey 1871. Descriptions of sixty new forms of mollusks from the west coast of North America and the North Pacific Ocean, with notes on others already described. Amer. Journ. Conch. 7 (2): 93-160; plts. 13 - 16 (2 November 1871) 1908. 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 “Albatross,” during 1891, Lieut.-Com- mander Z. L. Tanner, U. S. N., commanding. XX XVII. Reports on the scientific results of the expedition to the eastern tropical Pacific, in charge of Alexander Agassiz, by the U. S. Fish Commission steamer “Albatross,” from October, 1904, to March, 1905, Lieut.-Commander L. M. Garrett, U. S. N., commanding. XIV. The Mollusca and Brachio- poda. Bull. Mus. Comp. Zool. 43 (6): 205 - 487; plts. 1 - 22 (22 October 1908) Fast, T. N. 1960. Some aspects of the natural history of Stenobrachius leucopsarus Eigenmann and Eigenmann. Unpubl. thesis, Stanford Univ., 107 p. Figtps, W. Gorpon 1950. A preliminary report on the fishery and on the biology of the squid, Loligo opalescens. Calif. Fish & Game g6 (4): 366 - 367 1965. The structure, development, food relations, reproduction and life history of the squid Loligo opalescens Berry. Calif. Dept. Fish & Game, Fish Bull. 131: 1 - 108 FisHer, W. K. 1923. Brooding habits of a cephalopod. Ann. Mag. Nat. Hist. 12: 147 - 149 1925. On the habits of an Octopus. Ann. Mag. Nat. Hist. (9) 15: 411-414 Hocueerso, FG. 1974. Southern California records of the giant squid, Moroteuthis ro- busta. The Tabulata 7 (4): 83 - 85 Hoyze, Witiiam Evans 1904. Reports on the scientific results of the expedition to the eastern tropical Pacific ... Albatross. V. Reports on the Cephalopoda. Bull. Mus. Comp. Zool. Harvard 43 (1): 1-71; 10 plts. Lu, C. C. « M. R. Crarkez 1975. Vertical distribution of cephalopods at 40°N, 53°N and 60°N at 20° W in the North Atlantic. Journ. Mar. Biol. Assoc. U. K. 55: 143 - 163 McAL.ttsTeER, R. 1976. California marine fish landings for 1974. Game Fish Bull. 166: 1-53 McCosxer, J. E. e M. E. ANDERSON 1976. Aquarium maintenance of mesopelagic animals: a progress re- port. Bull. So. Calif. Acad. Sci. 75 (2): 211-219 McGowan, JoHN ARTHUR 1967. Distributional atlas of pelagic molluscs in the California Current region. Calif. COFI, atlas (6): 218 pp. OxutTani, TakasHi & JoHN ArTHUR McGowan 1969. Systematics, distribution and abundance of the epiplanktonic squid (Cephalopoda, Decapoda) larvae of the California Current, April, 1954 - March, 1957. Bull. Scripps Inst. Oceanogr. 14: 1 - 90 Pearcy, Witiiam G. 1965. Species composition and distribution of pelagic cephalopods from the Pacific Ocean off Oregon. Pacif. Sci. 19 (2): 261 - 266 1976. Seasonal and inshore-offshore variations in the standing stocks of micronekton and macrozooplankton off Oregon. Fish. Bull., NOAA 74 (1): 70-80 Pearcy, Witiiam G. & GitpertT LINCOLN Voss 1963. A new species of gonatid squid from the northeastern Pacific. Proc. Biol. Soc. Wash. 76: 105-112 Pgarcy, WitiiaM G., E. Kryorgr, R. Mesecar & F Ramsey 1977. Vertical distribution and migration of oceanic micronekton off Oregon. Deep-Sea Res. 24 (3): 223 - 246 Pereyra, W. T. 1965. New records and observations on the flapjack devilfish, Opistho- teuthis californiana Berry. Pacif. Sci. 19 (2): 427-441 Puituips, Juuius B. 1933. Description of a giant squid taken at Monterey with notes on other squid taken off the California coast. Calif. Fish & Game 1g (a): Calif. Fish & 128 - 136 1934. Octopi of California. Calif. Fish & Game 20(1): 20-29 1941. Squid canning at Monterey, California. Calif. Fish & Game 27 (4): 269-271 Page 262 THE VELIGER Vol. 21; No. 2 [—nctcne serene aan TIENT EETTTEESTEITEIEEETENIREEEEEEEEEmmmmemeeeneee Puiipps, Jurius B. 1961. Two unusual cephalopods taken near Monterey. Calif. Fish & Game 47 (4): 416-417 Roper, Crypez F E. « RicHarp E. Youno 1975. Vertical distribution of pelagic cephalopods. Smithson. Con- trib. Zool. (209): 1-51 ScorFileLp, W. L. 1924. Squid at Monterey. Calif. Fish & Game 10 (4): 176-182 SmitH, ALLyN GoopwIN 1963. More giant squids from California. Calif. Fish & Game 49 (3): 209-211; 1 text fig. (July 1963) Sorat, Ropert R. e F James Rowir 1969. Biometry. xxi+776 pp.; illust. San Francisco, Calif (W. EL Freeman and Co.) TaimapcE, Ropert RAYMOND 1967. Notes on cephalopods from northern California. The Veliger 10 (2): 200 - 202 (1 October 1967) Tucker, G. H. 1951. Relation of fishes and other organisms to the scattering of under- water sound. Journ. Mar. Res. 10 (2): 215-238 Warren, L. R., M. F Scweier « D. A. Rirey 1974. Colour changes of Octopus rubescens during attacks on uncon- ditioned and conditioned stimulli. Anim. Behav. 22: 211 - 219 WormutH, J. H. 1976. The biogeography and numerical taxonomy of the oegopsid squid family Ommastrephidae in the Pacific Ocean. Bull. Scripps Inst. Oceanogr. 23: 1-90 Youno, Ricnarp EpwarD 1972. The systematics and areal distribution of pelagic cephalopods from the seas off southern California. Smithson. Contrib. Zool. no. 97: 1- 159; plts. 1-38; 15 text figs.; 26 tables Vol. 21; No. 2 THE VELIGER Page 263 Antipredator Behavior in Octopus doflein (Wilker) BY B. HARTWICK, G. THORARINSSON anp L. TULLOCH Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada THE GIANT PaciFic octopus, Octopus dofleini (Wiilker, 1910), is a large and active predator in the marine sub- tidal. In spite of its own predaceous habits the octopus itself is a victim of attacks by a variety of other predators including seals (KENYON, 1965), sea otters (KENYON, 1975), dogfish sharks (BROCKLEsBY, 1927), lingcod (Brian Francis, pers. comm.) and, of course, man. During a study of the population ecology and behav- ilour of Octopus dofleini on the west coast of Vancouver Island, we recorded considerable evidence of predation on these organisms. Of 39 octopuses weighing between 0.37kg and 18.2kg collected subtidally in Clayoquot Sound, 66% had considerable scarring and 50% had par- tially amputated arms. This evidence along with reports from local divers who observed unidentified fish attacking a medium-sized octopus (Harley Regan, pers. comm.) sug- gests that octopuses are not the top carnivores that they would seem to be. As PACKARD (1963) and others (see for example, YouNG, 1958) have suggested the octopus is an animal which has a den for a base which it leaves to attack prey, and into which it withdraws if disturbed. The behaviour of an octopus can then be interpreted in terms of visual re- sponses involving an approach response and a withdrawal response (PACKARD, 1963). Packard gives the components of these responses for Octopus vulgaris as well as provid- ing an interpretation of other behaviour patterns includ- ing a sucker display, as responses lying along an approach- withdrawal axis. Although species like O. vulgaris have been well-studied, especially in the laboratory, similar observations are lacking for O. dofleini and reports on their behaviour in their natural environment are almost non-existent. After KyTE & CouRTNEY (1977) reported their observation of aggressive behaviour in O. dofleini, we attempted to compile our own observations on this animal. We have approached octopuses of various sizes in the dens and in the open; in some cases just to clear shells from a den and at other times to actually remove the octopus in an experimental harvest program. During our studies of Octopus dofleini we have checked many dens. The octopus inhabiting a den usually observes our activities around the den entrance with one eye only. In some cases one arm would uncurl out toward a diver and then withdraw back into the den. Aggressive encoun- ters were rare but several are reported later in this paper. In one case an octopus weighing approximately 2 kg was sufficiently disturbed by our collecting of shells at the den, to jet quickly away only to settle about 5 m above the den where it remained motionless. Moving away quickly or remaining motionless are two responses observed in O. dofleini and reported commonly in species like O. vul- garis. PACKARD (1963) describes the components of the withdrawal response of O. vulgaris. The head is depressed, the body blanched except for darkening around the eye and suckers, and the arms are curved back and upward. The funnel is directed at the stimulus. In our encounters with O. dofleini the octopus if approached in the open would usually remain cryptic and motionless as long as the diver remained some distance away. If this reactive distance was breached then the animal would flee. The distance at which an animal reacts by fleeing varied from a meter to almost nil. In one case an octopus estimated to be 4.5kg was found in the open and it remained mo- tionless even when the mantle was caressed. Numerous papillae were raised, however. Some of our best observations of antipredator behav- iour have arisen during the experimental harvesting proj- ect. In each case an occupied den had bleach squirted into it. The divers would then move off behind rocks to await emergence of the octopus. Puffs of silt from the den open- ing indicated that the animal was about to emerge. The octopus leaves the den and stops a meter or so outside. On seeing the divers the body of the octopus moves quickly down in what appears like a “ducking”’ move- ment. Since the octopuses view the diver with one eye only this movement may give some estimate of distance. With the first bob, the animal blanches. The whole body pales including the area around the eyes; unlike Octopus vulgaris which darkens the area around the eyes. The octopuses then spread their interbranchial webbing in one fluid motion by thrusting the arms out and backward although the tips are kept curled in close to the body. The octopus remains immobile in this position for several seconds after which it moves quickly back into the den Page 264 THE VELIGER Vol. 21; No. 2 ee eee eee eee e reer eee e reer rece eceeee eeeeeeee ————— or some other nearby hole if possible. If a den or hole is not accessible, the octopus swims up and away, often eject- ing ink directly at the diver. An octopus that has settled on the bottom after being chased has prominent horns behind the eyes and swollen papillae on its mantle. The dramatic display described above presumably startles a potential predator and permits the escape of the octopus. Interestingly the display had this effect on the divers at least in the first few instances and actually en- abled the animals to escape. Often the octopus would retreat quickly back into its den immediately after the display. The display certainly gives the animal an appear- ance of much larger size. Small octopuses did not give a complete display. Although they became pale, they did not extend their arms and usually they were very quick to flee. Such a response would seem appropriate for ani- mals which would be relatively small even in full display. Although Hicu (1976) suggested that the behaviour of Octopus dofleini was unpredictable, the observations we have made indicate predictable responses under certain circumstances. We did not observe any sucker displays in Octopus dofleini. The sucker display described in O. vulgaris by PACKARD (1961) is presumed to be an intraspecific display. A photograph of O. dofleini in High’s paper shows some resemblance to this display but no other evidence exists. However, measurements of maximum sucker size on arms of 39 specimens of O. dofleini indicate that the largest suckers in males are proportionately larger than those in the female (HARTWICK, 1977) and it may be that such a display is used during mating activities. In addition to the withdrawal display described earlier, octopuses show a particular attack or approach response. PACKARD (1963) describes this for Octopus vulgaris as a deep brownish-reddening of colour combined with orien- tation changes. We observed an octopus in the open and holding a crab; the colour of the octopus appeared as deep brown. KyTE & CourTNEy (1977) described a similar mot- tled reddish-brown colour for an octopus attacking an- other octopus; the opponent appeared blanched. Al- though we have not seen any aggressive encounters be- tween octopuses we have had such interactions with the animals ourselves. On October 24, 1976, two divers de- scended to a den located at 18m. Two large octopuses were present, one just inside the den, the other in front of the den. The one in front on seeing the divers several meters away moved up off the bottom spreading its web- bing and arms and taking on a dark brownish appearance. It then moved toward the divers and in fact kept advanc- ing even when the divers had retreated to a ledge at 10m. On Nov. 2 both octopuses were present inside the den which was actually a horizontal crevice. When we started to collect shells near the den one octopus moved out of the den towards us but stopped several meters away and then moved back into the den. On February 11, 1977 a light was shone into the same den which now held only one large octopus estimated to weigh 20 to 30kg. The octopus came directly out at the divers and when emerg- ing had an almost black colouration. Once out of the den, the octopus swam about 1m above the den in a single burst and extended all 8 of its arms; an unusual case since whenever we had encountered other octopuses in mid- water their reaction was to flee immediately leaving be- hind a trail of ink. No paling was observed by the divers and when the octopus settled to the ledge in front of the den its colour appeared totally black or very dark brown. The octopus then crawled toward the divers. Such aggres- sive encounters are of great interest. The battle observed by KyTE & CourTNEY (op. cit.) occurred in January and may have been related to reproductive activities or ter- ritoriality during the mating season. Although we have no evidence of territoriality in O. dofleini, their general level of aggression may be higher in late fall and early winter which is presumably the normal mating period. In fact, commercial divers (Rod Palm, pers. comm.) have reported a much higher frequency of attacks during this time. The full significance of this and other behaviour pat- terns in Octopus dofleini will only be understood through continued recording of observations of their behaviour in the natural environment. Literature Cited Brock essy, H. N. 1927. Determination of vitamin A content in liver oil of the dogfish Squalus sucklit. Con. Chem. Metal. 11: 238 - 239 Hartwick, E. B. in prep. Morphology of Octopus dofleint Hicu, WitiiaM L. 1976. The giant Pacific octopus. Kenyon, K. W. 1965. Food of harbour seals at Amchitka Island, Alaska. Journ. Mamm. 46: 103 - 104 1975- The sea otter in the eastern Pacific Ocean. New York, 352 pp. Kyte, Micuaer A. & Grecory W. CourTNEY 1977. A field observation of aggressive behavior between two North Pacific Octopus, Octopus dofleini martini. The Veliger 19 (4): 427-428; 1 pit. (1 April 1977) PackarD, ANDREW 1961. Sucker display of octopus. Nature, London 190: 736 - 737 1963. The behaviour of Octopus vulgaris. Bull. Inst. Oceanogr. Monaco, No. spec. 1D: 35-49 Youns, J. Z. 1958. Responses of untrained octopuses to various figures and the effect of removal of the vertical lobe. Proc. roy. Soc. Belg. 149: 463 - 483 Mar. Fish. Rev. 38 (9): 17-22 Dover Pub. Inc. Vol. 21; No. 2 THE VELIGER Page 265 Mating Behavior of Octopus joubint Robson BY JENNIFER A. MATHER Department of Psychology, Brandeis University, Waltham, Massachusetts 02154 INTRODUCTION were observed in this situation, octopuses were also iso- OBSERVATIONS ON THE SEXUAL BEHAVIOR of octopuses have been made for nearly 100 years; however, most studies have examined one or several matings of a single pair of animals in an aquarium. YouNc (1962) was one of the few investigators who observed mating in the field, and he described only a single instance. Earlier workers debated whether the mating behavior of Octo- pus vulgaris is “violent” (the male holds the female for- cibly) (KotiMan, 1876) or “peaceful” (there is no re- straint and contact is only by the male’s extension of his third right arm or hectocotylus) (Racovitza, 1894). Von OrELLI (1962) and Wopinsxy (1973) noted both types of approach in O. vulgaris. However, in other species, Haplochalaena maculosa (TRANTER & AUGUSTINE, 1973), Eledone cirrhosa and E. moschata (voN ORELLI, op. cit.) only “violent” mating was observed. These types of mating may be species-typical, but they are more likely affected by manipulations in moving and confining the animals (for instance, if they are territorial they will behave dif- ferently in their own territory than in another animal’s). While observations have shown a great variety in mating behavior, recent research has outlined some of the behavioral units that appear to be components of normal mating in at least a few octopus species. WELLS & WELLs (1972) described the Arch and Pump movement by which spermatophores are inserted through the si- phon into the tubular fold along the male’s third right arm (hectocotylus), and thus passed to the female. Woninsky (1973) described a rise in the respiration rate of the female during copulation which he attributed to the contact of the male’s hectocotylus with the female’s oviduct prior to spermatophore passage. The present re- port makes use of these units of sexual behavior to de- scribe mating in Octopus joubini Robson, 1929. Because O. joubini is very small, it was possible to confine sev- eral animals in a large tank without excessive crowding and create a fairly natural situation. Because few matings lated and paired repeatedly with the same animals in the smaller tanks. These two procedures allowed observations in both a near-normal and a controlled situation, and make it possible to describe mating behavior in terms of number of Arch and Pumps, duration of mating, sex of initiating animal, and rise in respiration of female. METHODS I. “Semi-Natural” Observations: Six Octopus joubini (3 males, 3 females) collected from St. Joseph Bay, Flor- ida, and flown to Boston, were confined in a plexiglass tank measuring Im X 1m X 30cm and filled with 180L sea water (to approximately 18cm), and were in captivity for 2 months before the observations. Plexiglass cube “homes” (2.5cm cubes with 4 dark sides, one open, and one clear for observation) were provided so the animals could hide during the day. Constant lighting was pro- vided by a dim red light overhead; during the day addi- tional lighting was provided by a white lamp beside the tank. This lamp was controlled by a timerset to the normal Boston day length and was corrected every 2 weeks. The octopuses were fed 12 Uca sp. fiddler crabs every 2 days (1 crab/octopus/day) from August until mid-November, when prey was changed to Nassarius sp. mud snails be- cause the Uca were no longer available (but the schedule was unchanged). No attempt was made to feed individual animals, but all were observed eating several times. Tem- perature was maintained at or near 25°C (+ 1°), salini- ty was monitored and corrected weekly, and 72 L of water was changed every second week to prevent the accumula- tion of nitrates. Observations were made without a blind because after the animals had been repeatedly exposed to the experimenter sitting quietly in a chair, they ceased to respond and were disrupted only by abrupt motion. Octopus joubini is strongly nocturnal, so all observations were made in the evening, at least 2 hours after sunset, Page 266 between 1900 and 2400 hours. Observations were made in November and December when all animals were physi- cally mature. When a pair of octopuses mated, preceding behavior was noted, female respiration rate rise observed, Arch and Pumps counted, and relative positions of the animals described. II. Pairing Observations: (a) Housing -Ten addition- al octopuses were isolated for pairing experiments. Be- tween matings they were kept in 18L- or 36L-capacity aquaria that were maintained at 25°C (+ 1°) with salin- ity corrected weekly and 4 of the water changed weekly to prevent accumulation of nitrates. Lighting was provided by a dim red overhead light at night and white room lights during the day, timed to the normal Boston day length and adjusted weekly. Plexiglass “homes” (5cm cubes with 2 ends transparent, 4 sides dark, with one of these half cut away to allow passage) were provided for the octopuses. Each octopus was offered 6 Uca fiddler crabs daily (an average of 1 - 2 were actually eaten). (b) Pairing — The 10 octopuses were grouped into 5 pairs. Originally 10 matings per pair were planned, but the sequence could not be completed for every pair be- cause 3 of the females laid eggs in early January. To minimize variation, the same male was always paired with the same female, after a constant deprivation time of 4 days. Pairings were made in 2 modified 18 L-capacity aqua- ria that were surrounded by an opaque plastic shield containing small observation slits. Octopuses were brought to one of the observation tanks in their “homes” and eased out, with the aid of a pencil if necessary. The female was brought out first, then the male; until the onset of observations 1 minute later the animals were kept sepa- rated by a transparent plexiglass partition. Until mating was initiated, the animals were observed through the peepholes, then the front panel of the blind was folded back to allow viewing (octopuses are not easily disturbed when they are mating). Since Octopus joubini are noc- turnal, matings were initiated during their active period, between 2100 and 2400 hours. Octopuses were left in the tank 30 minutes after their mating to ensure that they had finished (a single exception was made when a large female cornered and attacked a small male). Observa- tions were dictated into a portable tape recorder and later transcribed. The number and spacings of Arches and Pumps, presence of an increase in female respiration rate, initiation, termination and duration of mating, and rela- tive position of the octopuses were recorded. Females ex- pelled spermatophores during mating and this evagina- tion process was observed carefully. THE VELIGER Vol. 21; No. 2 RESULTS Thirty-two matings were observed in the pairing situation and 6 in the semi-natural situation. (a) Duration: Matings were nearly always brief; the mean duration for all matings was 5.4 min. (5.0 min. for pairings and 6.5 min. for semi-natural) (Table 1). Table 1 Some Characteristics of the Mating Behavior of Octopus joubini Robson Semi-Natural Factor Repeated Pairings Situation (n = 32) (n = 6) Duration 5.0 min 6.5 min (Range 2-28 min) (Range 4-9 min) Number of Arch 1.8 2.3 and Pumps (Range 1-13) (Range 2-3) Female Respiration Rise 59% 100% (n = 5) Sex of Initiator Male = 19% Male = 84% Both = 9% Both = 16% Female= 72% Sex of Terminator Male = 12% Male = 33% Both = 25% Female= 66% Female= 63% Close contact = 94% Distance = 6% Close contact = 50% Distance = 50% Mating Position (b) Arch and Pumps: Few Arch and Pump mo- tions were observed, an average of 1.9 (1.8 for pairings, 2.3 for semi-natural (Table 1). The average interval between Arch and Pumps was also brief, 1 - 3 min. (1.3 min. for pairings, 1.4 min. for semi-natural). This feature of copulation was very stable, with a range of 0.33 to 5 minutes, but over half (29/48) at 1 minute. (c) Mating Initiation and Termination: — The pairing and semi-natural situations differed in the amount of contact made when mating was initiated. In the semi- natural situation, 3 matings (50%) began with the male simply probing the female’s home with his hectocotylus. Only 6% of the matings in the pairing situation were initiated in this fashion. The availability of homes in the semi-natural situation may account for this, and the high- er percentage of male initiation of mating (83%, com- pared to 41% in the pairings). Termination of mating Vol. 21; No. 2 THE VELIGER Page 267 EE anE SEES mana was more uniform, being initiated normally by the female, 66% of the time in the semi-natural setting and 637% of the time in the pairing situation (Table 1). (d) Respiration Rate: An increase in respiration rate was observed in 5 matings in the semi-natural situa- tion (in the other, the female was only partly visible ) for 100%. but only in 59% of the pairings. (e) Mating Position: Nearly all (94%) of matings in pairings were with close contact, but only 507% of the matings in the semi-natural setting were in this position. DISCUSSION Despite the small number of matings observed in the semi-natural situation, it is worthwhile to contrast them with the matings in the pairing situation because copula- tions under relatively natural conditions have rarely been described for octopuses. Some aspects of mating such as number of Arch and Pump motions, Inter-Arch-and- Pump Interval, and total duration of mating appear stable. But other aspects, such as amount of contact during mating, and sex of the octopus initiating and ter- minating mating, seem to be more variable and may be influenced by the experimental situation. Most pairing matings were in close proximity but most semi-natural ones were not; this confirms WopInsky’s (1973) and von OrELLIs (1962) conclusion that no one contact pattern is species-typical for any one octopus species. VON ORELLI (op. cit.) ascribed differences in mating procedure both to relative size of the animals and to female behavior; in Octopus joubini, it may also be affected by the space and homes available to the female. For example, if one animal is in its home tank then it may be more likely to initiate mating (WELLS & WELLS, 1972, for O. vulgaris and O. cyanea). The initiation of mating by female O. joubini in the pairing situation, which was not seen in semi-natural situations, may be related to the female being placed in the mating tank before the male. Octopus joubini matings are very short (5 minutes) when compared with those of other Octopus species. Oc- topus dofleini copulated 2-3 hours (MANN, MarTIN & TuierscH, 1970), Haplochalaena maculosa 1 hour (TRANTER & AUGUSTINE, 1973), and Eledone up to an hour (von ORE LI, 1962). Short matings, and thus a short period of vulnerability, would be adaptive for a small (15 - 20g) octopus that is vulnerable to many predators (Haplochalaena is small, but deadly venomous). Never- theless, short mating duration may impede one aspect of reproduction. Octopus sperm are passed to the female in a spermatophore that evaginates in the female’s oviduct, depositing sperm in the oviducal gland. Normally the male holds the spermatophore in the female until evagi- nation is completed, one hour for O. dofleint (MANN, Martin & THIERSCH, op. cit.) 14 to 3 min. for O. vul- garis (DREW, 1919). However, male O. jowbini cannot hold the spermatophore until evagination because this process takes too long. Evagination of loose spermato- phores takes approximately 20 minutes, much longer than a total mating. Apparently in O. joubini the spermato- phore may be kept in the oviduct by a mechanical pro- cess; for example, in loose spermatophores the anterior portion of the casing swells up like a bulb within 5 min- utes after contact with sea water. Such an action would maintain the spermatophore in the oviduct and provide for both short matings and longer transfer times for sperm from the spermatophore. These observations suggest that some aspects of mating, such as Arch and Pump movements, may be stereotyped in occurrence and common among octopods. Others, such as mating duration and position, may be more labile within and among species, and more affected by experi- menter manipulation. ACKNOWLEDGMENTS I would like to thank Dr. J. Wodinsky, Dr. J. R. Lackner, and my husband for their assistance and support. Literature Cited Drew, G. A. 1919. The structure and ejaculation of the spermatophores of Octopus americana. Pap. Dept. Mar. Biol. Carnegie Inst. Publ. 281: 35 - 45 Koiiman, J. 1876. Die Cephalopoden in der Zoologischen Station des Dr. Dohrn. Zeitschr. Wissensch. Zool. 26: 1 - 23 Mann, T., A. W. Martin « J. B. TH1erscH 1970. Male reproductive tract, spermatophores and spermatophoric re- action in the giant octopus of the North Pacific, Octopus dofleini mar- tint. Proc. Roy. Soc. London B 175: 31-61 VON OreLLI, M. 1962. Die Ubertragung der Spermatophoren von Octopus vulgaris und Eledone (Cephalopoda). Rev. Suisse Zool. 69: 193 - 202 Racovitza, E. G. 1894. Notes de biologie. Accouplement et fécondation chez ]’Octopus vulgaris Lam. Arch. Zool. Exp. Gen. 2: 23-49 TranTER, D. J. 2 O. AUGUSTINE 1973. Observations on the life history of the blue-ringed octopus Hap- lochlaena maculosa. Mar. Biol. 18: 115-128 We ts, M. J. e J. WeLts 1972. Sexual displays and mating in Octopus vulgaris Cuvier and O. cyanea Gray and attempts to alter performance by manipulating the glandular condition of the animals. Animal Behav. 20: 293 - 308 Woornsky, J. 1973. Ventilation rate and copulation in Octopus vulgaris. Mar. Biol. 20: 154 - 164 Youna, J. Z. 1961. Courtship and mating by a coral reef octopus (O. horridus). Proc. Zool. Soc. London 138: 157 - 162 Page 268 THE VELIGER Vol. 21; No. 2 Growth in the Keyhole Limpet Fissurella crassa Lamarck (Mollusca : Archaeogastropoda ) in Northern Chile MARTA BRETOS Laboratorio de Ecologia Marina, Centro de Investigaciones Marinas Universidad del Norte Sede Iquique, Casilla 65, Iquique, Chile (5 Text figures) INTRODUCTION AMONG THE SPECIES OF MOLLUSKS commercially exploited for food in the Iquique region. Chile, the keyhole limpets of the genus Fissurella Bruguiére, 1789, collectively called “lapas;’ are important. The various species of Fissurella are often eaten instead of Concholepas concholepas (Bru- guiére, 1789) because this last species is diminishing due to intensive exploitation. Fissurella species are not pro- tected by laws preventing small specimens to be collected and eaten, in spite of the great predation exerted on them by man. In order to manage adequately or control a population, growth rate must be determined. However. there is little information on growth rate of commercially important Archaeogastropoda, Sakai (1960), LEIGHTON & BooLooti- AN (1963), and WricuT (1976) have carried out studies on growth rate of Haliotis species, but we have not found data concerning growth rate of Fissurella species. Fissurella crassa Lamarck, 1822, locally called “lapa desol,” was cho- sen for the present study because it has been one of the most exploited species of the genus. MATERIALS anp METHODS The specimens selected for this study lived between the Chthamalus and Lessonza belts throughout the rocky inter- tidal area in front of the Laboratorio de Ecologia Marina, Universidad del Norte (LEM1I), at Huayquique, Iquique, ' This research project was supported by the Universidad del Norte Sede Iquique Chile (20°17’S, 70°08’ W). They were marked and meas- ured individually after being gently removed. Animals were marked in three ways: (1) Small num- bered tags were glued to the clean, dry shell and covered with Dekophane adhesive (Rona Pearl Inc., Bayonne, New Jersey). This method was not entirely satisfactory. Even when the glue set properly, epibiontic limpets (Scurria parasitica (ORBIGNY, 1841) sometimes grazed the numbers off, or algae and cirripeds set on the numbers, or the num- bers became erased. (2) Small numbered tags were glued on the shell and covered with Revell cement (Revell, Ltd., Great Britain). This method was not more satisfactory than the former. (3) Serial notches were sawed near the apical orifice and on the shell margin. Growth did not greatly dis- turb the identification notches. The notches also were easily detected in recaptured animals. These marks per- sisted longer than the numbered tags, thereby providing the best way of marking, and were easily renewed when fading. Their influence on the physiology of shell growth was not evaluated. The size of marked animals varied between 20 and 77 mm of shell length as initial size; specimens smaller than 20 mm were difficult to mark. Periodically new animals were marked during the first year until a total of 360 was reached. Animals which lost their numbered tags could sometimes be identified by their size, the quantity and po- sition of their epibionts, and their position in the field. In such case they were retagged. Growth was measured to 0.1 mm using vernier calipers. Shell length was usually measured once a month during low tides when wave impact was not strong. Length incre- ments were standardized to: length increments per year = length increments X number of days between the first and Vol. 21; No. 2 last measurements/365, (WRIGHT, 1976). The relation be- tween annual growth rate and age was established by using Walford’s graphic (WALForD, 1946). Growth rates (length increment/number of days between two successive growth measurements) were calculated for every marked animal. Mean growth rates of all size animals observed during the same period were calculated and plotted against time to detect seasonal growth variations. Animals were measured for 19 months. The data pre- sented below concern 88 animals which were measured for at least 100 days. Monthly mean surface sea water temperatures at 8:30 and 13:30 hr were taken from the data records of the LEMI. The extreme temperatures registered during the study period were 13° and 24°C, respectively. RESULTS Of 360 marked individuals, 153 were never recaptured (42.5%): these comprised 42.9% of the animals bearing numbered tags and 38.9% of the notched animals. Of the remaining 207, only 88 (24.4% of the total) were recap- 25 20 L & = o 3 -4 Ss s 10 2 io) 5 ce) 20 30 40 THE VELIGER Page 269 tured from 3 to 15, times during the observation period, and 15, of which were measured for at least one year. In the experimental rocky area Fissurella crassa feeds mainly on green algae such as Ulva sp. and Enteromorpha sp. It usually moves to feed when covered by sea water dur- ing high tides, at night, returning to home sites during diurnal low tides. A home site may neither be the same nor last for the whole life of a given individual. For instance, small animals (20- 30 mm shell length) change their home sites more often than large sized specimens do. Moreover, some may return to the same rocky hollows from 1 to 6 months, but they usually migrate downwards to the Les- sonia sp. intertidal and subtidal belt in spring. Others do not stay at the same site and at successive growth determi- nations were found at sites 0.6 to 20.0 m away from the last location observed. The individuals staying longer at their home sites were those living in clefts about 10 to 50cm deep. One particular specimen has been observed for 15 months in the same cleft. The growth rate for each studied Fissurella is presented in Figure 1. Growth rate was highly variable even for indi- viduals of close or similar initial size (Figures 1, 2). Y = 27.054 - 0.3264574% r = -0.7466 N = 88 5° 60 70 80 Initial Size in mm Figure 1 Growth rate for each Fissurella crassa measured for 100 days or more Page 270 THE VELIGER Vol. 21; No. 2 80 60 g #50 3 = wn 40 30 20 Oct Nov Jan Mar May July Sep Nov Jan Mar May 1975 1976 1977 5 Date Figure 2 Individual growth of Fissurella crassa followed through the seasons (23 individuals represented) Fissurella crassa seems to exhibit a seasonal growth pat- Table 1 tern. A rapid growth coinciding roughly with a period of rising temperatures was observed in spring (Figures 3, 4). The mean growth rate was diminished in late spring and Frequency of Growth Rates Observed in early summer to values as low as those found in winter. Seasons Different from Winter in This decrease is followed by an accelerated growth that Fissurella crassa from 40 to 77 mm of Shell Length. declines again in late autumn. Low growth rates were re- corded in winter months. It should be noted that the Numbentot Growth Rate mm/day winter decrease in growth rate is a rather general feature Month — individuals Range Mean _ Stand. Dev. of the Fissurella crassa population under study. Neverthe- RGR A 5 0.0000-0.0081 0.0039 0.0028 less, the low growth rate observed in December-January yecember ll 0.0000-0.0071 0.0043 0.0028 (Figure 4) corresponds to a mean value. Forty-one ani- January 13 0.0000 -0.0083 0.0036 0.0030 mals presented very little growth (under o.ormm per _ February 6 0.0000- 0.0090 0.0044 0.0034 day) or no growth at all for a short period from Novem- March 4 0.0017 - 0.0076 0.0058 0.0023 ber to April, the highest incidence of no growth occurring “P™"! i ete Ce CN in January (Table 1). The rest of the animals showed TONAL Si diverse growth rates during that period. Vol. 21; No. 2 Growth Rate (mm/year) Oo THE VELIGER Page 271 60 80 Shell Length in mm Figure 4 Mean seasonal growth pattern of Fissurella crassa at Huayquique The mean growth rates for the different size classes indi- cate that growth would be 19.8mm for the second year, 14.5 mm for the third, 9.7 mm for the fourth and 6.8mm for the fifth. The usual commercial size of F. crassa is about 45-65 mm, although smaller specimens can often be ob- served in the market. If we assume that during the first year fissurellas grow to about 20mm, commercial sizes should correspond to animals from 2 to 4 years old (Fig- ure 5B). According to Walford’s graph (Figure 5A), maximum probable size for F. crassa is about 83 mm of shell length. This estimation agrees with reality since maximum size ob- served in Northern Chile for this species is 81.8mm at Present. Twelve empty tagged shells were found in clefts in the study rocky area, probably left by predators. We cannot as- sume that this is the only real mortality of the population under study because its location in the field and the strong swell do not allow gathering every empty tagged shell. DISCUSSION Using notches to mark F. crassa, we failed to recapture 38.9% of the individuals. The loss of these animals could be attributed to death or to migration, probably to the sur- rounding subtidal zone. Removing the animals to be marked and measured should not disturb them to make them move, since some Page 272 THE VELIGER Vol. 21; No. 2 Temperature °C Oct Nov Jan Mar May July Sep Nov Jan Mar May 1975 1976 Dite 1977 Figure 3 Monthly mean surface sea temperature at Huayquique. Solid line represents temperatures at 15:30 hr; dotted line repre- sents temperatures at 8:30 hr. L. = 83.04 mm 80 2 60 er a z io) 5 2 A 40 e B 20 = I 2 3 4 5 6 7 8 Age in years Figure 5 A. Mean growth of Fissurella crassa plotted according to Walford’s method B. Estimated age of Fissurella crassa at Huayquique Vol. 21; No. 2 245) 20 © i Sanne ol = & i= E i} = a4 = ES S 410 - S) 5 THE VELIGER Page 271 Shell Length in mm Figure 3 Monthly mean surface sea temperature at Huayquique. Solid line represents temperatures at 15:30 hr; dotted line repre- sents temperatures at 8:30 hr. The mean growth rates for the different size classes indi- cate that growth would be 19.8mm for the second year, 14.5 mm for the third, 9.7 mm for the fourth and 6.8mm for the fifth. The usual commercial size of F. crassa is about 45-65 mm, although smaller specimens can often be ob- served in the market. If we assume that during the first year fissurellas grow to about 20mm, commercial sizes should correspond to animals from 2 to 4 years old (Fig- ure 5B). According to Walford’s graph (Figure 5A), maximum probable size for F. crassa is about 83 mm of shell length. This estimation agrees with reality since maximum size ob- served in Northern Chile for this species is 81.8mm at present. Twelve empty tagged shells were found in clefts in the study rocky area, probably left by predators. We cannot as- sume that this is the only real mortality of the population under study because its location in the field and the strong swell do not allow gathering every empty tagged shell. DISCUSSION Using notches to mark F. crassa, we failed to recapture 38.9% of the individuals. The loss of these animals could be attributed to death or to migration, probably to the sur- rounding subtidal zone. Removing the animals to be marked and measured should not disturb them to make them move, since some Page 272 THE VELIGER Vol. 21; No. 2 Temperature °C Oct Nov Jan Mar May July Sep Nov Jan Mar May 1975 1976 Date 1977 Figure 4 Mean seasonal growth pattern of Fissurella crassa at Huayquique 0.06 = z iS E = Oey oO 3 m4 s > p 1) S 5 a 0.02 fo) Seer Nev Jan Mar May July Sep Nov Jan Mar May ai 1978 Date 1977 Figure 5 A. Mean growth of Fissurella crassa plotted according to Walford’s method B. Estimated age of Fissurella crassa at Huayquique Vol. 21; No. 2 THE VELIGER Page 273 of them. although repeatedly measured for a year or more. have always stayed at their home sites. Furthermore, ani- mals used for growth studies which have been marked and measured in sift’ (WRIGHT. 1976) have immediately dis- appeared after having been marked or have not been found over successive measurement periods. as we have also ob- served in some individuals of F. crassa. Great individual variations in growth rate among sim- ilar sized animals of the same species are a feature common to various gastropods. such as Haliotis (LEIGHTON & Boo- LOOTIAN. 1963; WRIGHT. 1976), Patella (LEWIs & BOWMAN, 1975). Acmaea (FRANK. 1965). and Purpura lapillus (Moore. 1938). This is the case with Fissurella crassa, too. These variations can be due to several factors. In Littori- nid species some growth rate variations correspond to sex differences, females growing faster than males (BorKows- KI, 1974). Since no external signs of sexual dimorphism are observed in Fissurella crassa, we could not detect sexual growth differences. Growth rate can also vary from one lo- cality to another (Moore, 1938; LEIGHTON & BOOLOOTIAN, 1963; BorKoWSKI, 1974) in relation with the food avail- ability in each locality. Moore (1938) observed that Pur- pura lapillus specimens feeding on different diets stopped growing at different sizes. HAVEN (1973) detected that a growth increase in Acmaea was accompanied by an algal upgrowth. In our study area home sites of Fissurella crassa are not identical and in different clefts diverse microcli- mates develop. Algae in the intertidal zone vary seasonally, so the food resources for F. crassa are also variable. It should be considered in addition that F. crassa in this area do not always stay at the same sites. Some individuals usually ob- served in winter in the intertidal zone between the Colpo- menia and Lessonia belts migrate in summer downwards to lower clefts in the Lessonia belt and they can even be ob- served on rocks at 1 m below the extreme low water level. At this level F. crassa may have a different food supply and may compete for food with other grazers such as chitons, sea urchins and other species of Fissurella. Finally, the sea flow received by every cleft is not identical and this may be another factor influencing growth rate, as has been sug- gested by FIscHER-PIETTE (1939) for Patella vulgata. Summer growth rate decrease coinciding with the begin- ning of the spawning season has been described for Litto- rinids (BORKOWSKI, 1974). The spawning season for Fissurella crassa has not been determined; there may be a spawning period when the summer growth rate decrease is observed. SUMMARY The growth of the commercially important keyhole limpet Fissurella crassa was studied along the intertidal rocky shore of Huayquique, Northern Chile. A total of 360 an- imals were marked, using numbered little tags or notches. and measured during 19 months. Only 88 individuals (24.4%) were recaptured enough times to be analyzed. Growth rate among individuals of similar initial size was highly variable. Fissurella crassa seems to have a seasonal growth pattern. Rapid growth was observed in spring; then mean growth rate diminished in late spring and early summer, followed by an accelerated growth that declined in autumn and was low in winter months. A relation between mean growth rates and age of this species is proposed. Accordingly, commercial si- zes should correspond to animals from 2 to 4 years old. Maximum probable size for this species is about 83 mm of shell length. Factors that may influence growth are discussed. ACKNOWLEDGMENTS I wish to thank Professor Dr. Robert T. Paine for his in- terest in my research and helpful advice. I am grateful to Professor Nibaldo Bahamonde, to Dr. José Stuardo and to Professor Francisco Riveros-Zuniga who made useful sug- gestions to the manuscript. I am specially indebted to my husband for his continuous encouragement. Literature Cited BorKowskI, THomas V. 1974. Growth, mortality, and productivity of south Floridian Littor- inidae (Gastropoda: Prosobranchia). Bull. Mar. Sci. 24: 409 - 438 FiscHerR-PiettTe, E. 1939. Sur la croissance et la longévité de Patella vulgata L. en fonc- tion du milieu. Journ. de Conchyl. 8g: 303 - 310 Frank, PeteR WOLFGANG 1965. Growth of three species of Acmaea. 201 - 202; 1 text fig. Haven, STONER BLACKMAN 1973- Competition for food between the intertidal gastropods Acmaea scabra and Acmaea digitalis. Ecology 54 (1): 143-151 Leicuton, Davip « RicHarD A. BooLooTiIAN 1963. Diet and growth in the black abalone, Haliotis cracherodit. Ecology 44 (2): 227-244 Lewis, J. R. « Rosemary S. BowmMANn 1975- Local habitat-induced variations in the population dynamics of Patella vulgata L. Journ. exp. mar. Biol. Ecol. 17: 165 - 203 Moore, Hivary B. 1938. The biology of Purpura lapillus. Part II. Growth. Journ. mar. biol. Assoc. U. K. 283: 57 - 66 Sakal, SEICHI 1960. On the formation of the annual rings on the shell of the aba- lone, Haliotts discus var. hannai Ino. Tohoku Journ. Agric. Res. 11 (3): 239-244 Watrorp, Lionet A. 1946. A new graphic method of describing the growth of animals. Biol. Bull. go: 141 - 147 Wricut, Mary Bercen 1976. Growth in the black abalone, Haliotis cracherodit. The Veliger 18 (2): 194-199; 4 text figs. (1 October 1976) The Veliger 7 (3): (1 January 1965) Page 274 THE VELIGER Vol. 21; No. 2 Abnormality of Shell Plates in Three Chitons from New England BY PAUL. D. LANGER (1 Plate) INTRODUCTION MORPHOLOGICAL VARIATION from the normal chiton shell plate number of eight has been reported by over forty authors. These reports were partially summarized by Tak1 (1932). FISCHER-PIETTE & FRANC (1960), and BURGHARDT & BuRGHARDT (1960). The occurrence of morphological variation among three species of circumboreal chitons. Tonicella rubra (Lin- naeus. 1767), T. marmorea (Fabricius, 1780), and Isch- nochiton albus (Linnaeus, 1767). was studied in two sep- arate populations in northeastern New England. This paper presents a brief description of the types encoun- tered, their frequency of occurrence, subtidal distribution, and attempts to relate these factors to environmental se- verity. MATERIALS anp METHODS Samples were collected monthly for two years from sub- tidal rock substrates using SCUBA. At Deep Cove in East- port, Maine, the substrate within the sampling quadrat was placed in fine mesh bags at each of ten stations from mean low water to 13.5 m. This procedure insured an un- biased sampling of all size groups. Differences in substrate size and composition at Cape Neddick in York, Maine, necessitated a different sampling approach. Individual chitons were removed from rocks with forceps and placed in separate vials. All samples were preserved in 10% buffered formalin and later transferred to 70% alcohol. RESULTS Table 1 presents a summary of the types of morphological variation identified, their frequency, and geographic loca- tion. All of the variants had less than eight shell plates: 74,7, or 6. The most frequent type encountered for Toni- cella rubra (Figures 1 & 2), T. marmorea (Figure 3), and Table 1 Frequency of Morphological Variation among Three Chiton Species. Site Shell Species Plate Deep Cove Cape Neddick Number % %e Tontcella (2166)! (1292)! rubra 7% 0.14 — 7 0.46 0.54 6 0.046 — Tonicella (1149)! (487)! marmorea 72 — — 7 0.35 0.21 6 0.087 — Ischnochiton (528)! (—)? albus 72 0.19 7 0.19 6 : = 'Sample size 2Absent from site Explanation of Figures 1 to 8 Figure 7: Tonicella rubra, 7 shell plates; length, 11.7mm Figure 2: Tonicella rubra, 7 shell plates; length, 8.4mm Figure 3: Tonicella marmorea, 7 shell plates, length, 14.0mm Figure 4: Ischnochiton albus, 7 shell plates; length, 9.9mm Figure 5: Tonicella rubra, 7} shell plates; length, 16.4 mm Figures 6 and 7: Ischnochiton albus, 74 shell plates; length, 9.6 mm. Views showing highly modified 7 plate Figure 8: Tonicella marmorea, 6 shell plates; length, 8.1 mm THE VELIGER, Vol. 21, No. 2 [LANGER] Figures 7 to 3 Vol. 21; No. 2 THE VELIGER Page 275 Ischnochiton albus (Figure 4) was the seven plated form. The 7% plated variety, first described by OLIVER (1921). was found among 7. rubra (Figure 5) and /. albus (Figures 6 & 7) populations, while the least common six plated form was represented only by the two Tonicella species (Figure 8). The frequency of all variant forms equaled or com- prised less than one half of one percent of the total popula- tion. The diversity of variation was lower at the more ex- posed site. Cape Neddick. Table 2 Frequency of Morphological Variation by Depth for Deep Cove. Tonicella Tonicella Ischnochiton Depth rubra marmored albus (m) fs 7s % MLW 0.00 ().00 0.00 5) ().87 0.00. 0.00 3.0 0.46 1.30 0.00 4.5 0.84 0.00 1.70 6.0 0.55 1.10 0.79 7.5 1.26 0.45 0.00 9.0-13.5 0.00 0.00 0.00 Table 2 presents the benthic distribution of morpho- logical variation. Data indicate there was no correlation between depth and variant frequency or depth and variant type. A correlation occurred between frequency of varia- tion and the depth intervals of greatest population density. DISCUSSION This is the first report of shell plate variation among Toni- cella marmoreaand Ischnochiton albus. According to Taki (1932: 59). BLANEY (1904) reported a six plated T. rubra. However. no mention of this was found in BLaney’s (1904) original paper. The benthic distribution of variants and their greater frequency at the environmentally less severe Deep Cove site suggest that occurrence of variants is not directly in- fluenced by surf-related factors, temperature, or salinity extremes. The frequency of variation did correlate with population density. If the variants are genetic mutants, then it logically follows that they are most frequent at depths of greatest population concentration. However, if the survival of mutants was selected against by environ- mental extremes, this would reduce their appearance at the more severe site, Cape Neddick. It seems unlikely that shell plate aberration would physically impair the survival of subtidal chitons. Literature Cited Bianey, Dwicut 1904. Shell collecting days at Frenchman’s Bay. 17 (10): 109-111 Burcuarpt, GLenn E. & Laura E. BurGHARDT 1969. Report on some abnormal chitons from California and British Columbia. The Veliger 12 (2): 228-229 (1 October 1969) FiscHer-Piette, E. & A. FRANC 1960. Classe des polyplacophores. 1701 - 1785 Ouiver, W. R. B. 1921. Variation in Amphineura. Wellington 53: 361 Taxi, Iwao 1932. On some cases of abnormality of the shell plates in chitons. Mem. Coll. Sci. Kyoto 8 (1): 27-64 The Nautilus (5 March 1904) in: Grassé’s Traité de Zoologie 5: Trans. Proc. New Zeal. Inst. Page 276 THE VELIGER Vol. 21; No. 2 Accumulation of '*C-Labelled Algal Exudate by Mytilus californianus Conrad and Mytilus edulis Linnaeus, An Aspect of Interspecific Competition P V. FANKBONER, Wn. M. BLAYLOCK anp M. E. pe BURGH Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 (1 Plate; 3 Text figures) INTRODUCTION THE CALIFORNIA SEA MUSSEL, Mytilus californianus, forms extensive beds in surf-swept rocky habitats along the Pa- cific Coast of North America (RICKETTS & CALVIN, 1952). The smaller, more cosmopolitan bay mussel Myt:lus edulis lives in the same geographical region but is not at home in crashing waves and inhabits more protected bays, inlets and backwaters (JOHNSON & SNOOK, 1927). Both bivalve species (Figure 7) have adaptive features appropriate to their environments. For example, M. californianus posses- ses a heavy shell and a robust byssus for withstanding heavy wave shock. M. edulis, on the other hand, has a more delli- cate shell and is more weakly attached to the substratum, but its ability to crawl and thus avoid being smothered by sediments contributes to its success in quiet waters (HaR- GER, 1968 and 1971). However, there are instances where the two mussel species overlap (BLAYLocK, 1978), and this condition indicates that factors other than morphological and behavioural differences may favor niche separation between these two mytilids. In many sympatric animal spe- cies, competition for food is one of the most significant factors limiting their distribution (Cox, HEALY & Moore, 1973). Thus, in view of the occasional, and usually inex- plicable, distributional overlap of Mytilus californianus with M. edulis, we have examined feeding in the two spe- cies to explain differences in niche. The Mytilidae, like the majority of bivalved Mollusca, filter feed upon particulate material in suspension (Mor- TON, 1967). In addition, there is evidence which suggests that mussels are capable of accumulating dissolved organic carbon compounds present in seawater (STEPHENS & SCHINSKE, 1961; PEQUIGNAT, 1973; WRIGHT, 1976). Brown macrophytes release photosynthetically fixed dis- solved and particulate carbon as a physiological function of normal growth (SIEBURTH & JENSEN, 1968; BRYLINSKY, 1977). Amounts of organic carbon released by these algae comprised a relatively small portion (usually <1%) of the carbon fixed (BRYLINSKY, 1977; FANKBONER & DE BURGH, 1977), but significantly, this material is accumulated by marine invertebrates 1m situ (FANKBONER, 1976; FANK- BONER & DRUEHL, 1976) and thus may be assumed to be a normal component of their diets. In this study, we have placed specimens of Mytilus cali- fornianus and M. edulis in direct competition for *C- labelled dissolved organic carbon (DOC) and particulate organic carbon (POC) exudated by a cohabiting kelp Macrocystis integrifolia Bory. We have used algal exu- dated material rather than specific synthetic substrates be- cause it may more accurately represent food material avail- able in situ to M. californianus and M. edulis. MATERIALS anp METHODS Preparation of “C-labelled organic carbon compounds: A single blade from the frond of Macrocystis integnfolia was enclosed with 2.0 L of ambient seawater plus 1.0 mC of NaH"COs (Atomic Energy of Canada) in a clear polyethy- lene 6.5 x 17.5 x 38 cm bag. This provided a “C source for photosynthesis leading to production of materials exu- dated as isotope labelled dissolved organic carbon and particulate organic carbon. Blades were selected from M. integrifolia which were obviously healthy, advanced in growth (50-70 cm in length) but immature. If mature or late growth blades are used for producing algal exudation Vol. 21; No. 2 materials, one runs the risk of obtaining the products of microbial decomposition of plant tissue rather than algal exudate per se (FANKBONER & DE BURGH, 1977). The kelp blade was incubated for 24 hin the “C-labelled bag waters. At the end of the incubation period, the incu- bation waters were removed and processed as follows for feeding “C-labelled particulate and dissolved organic car- bon compounds to Mytilus. Particulate organic carbon (POC): Incubation waters from the blade of Macrocystis integrifolia consist of three categories of ‘C-labelled components; these include dis- solved organic carbon (DOC), dissolved inorganic carbon (DIC) and particulate organic carbon (POC). HaMMOoN & OsBoRNE (1959) have demonstrated that representatives from 12 major invertebrate phyla are capable of fixing DIC into acids of the Krebs’ citric acid cycle. The signif- icance of carbon fixation of these organisms remains to be assessed, but to prevent loss of precision in our DOC accu- mulation determinations, we removed DIC from the incu- bation waters by acidification prior to separation of DOC from POC. Kelp blade incubation waters were acidified with concentrated HCl to pH 2.5 and left standing in a fume hood for several hours to evolve *COz. Next, the pH of the incubation waters was readjusted to pH 7.9 by addition of solid pellets of NaOH; 500mL of the incuba- tion waters were used, as is. to provide a "C-labelled par- ticulate organic carbon fraction for feeding to the mussels. Because this medium contains both labelled DOC and POC, "'C-activity of POC may be estimated by the sub- traction method using activity data taken from isolated C-labelled DOC below. Dissolved organic carbon (DOC): The second 500mL volume of the *C-DIC free kelp incubation waters was fil- tered through 0.22 wm Millipore membranes to separate “C-labelled DOC from the particulate portion of the waters. Composition of kelp exudated DOC and POC: Trans- location studies on brown macrophytes (NICHOLSON & Brices, 1972; SCHMITZ & SRIVASTAVA, 1974a & 1974b) in- dicate that the DOC fraction of kelp exudation material isa 1:1 mixture of D-mannitol and amino acids. However, the particulate component of kelp exudate or algal humic material (SIEBURTH & JENSEN, 1968; SIEBURTH, 1969) is less well understood. It is not within the scope of this study to delve into the biochemistry of kelp exudated POC; however, we have described the gross morphological fea- tures characterizing exudation particulates via scanning electron microscopy. THE VELIGER Page 277 To view the physical structure of particulate material fed to our experimental animals, a 1.0mL sample of algal exudate was filtered through a 0.22 ym Millipore mem- brane. Next, the particulate coated filter was fixed for one hour ina solution of 4% glutaraldehyde buffered in 0.2 M cacodylate at pH 7.4. The 4% glutaraldehyde solution was formulated from a 25% prebuffered (3% calcium carbo- nate) stock solution of ‘Fisher’ biological grade glutaral- dehyde. Following a brief rinse in distilled water, the particulate matter was post-fixed for 24 hours in 2% os- mium tetroxide buffered with Dorey’s Solution B (Dorey, 1965). Following a brief rinse in distilled water, the fixed material was dehydrated by first quenching it in liquid nitrogen, and then freeze drying under vacuum. The dried POC (still upon the membrane filter) was mounted on a stub, gold coated, viewed and photographed using an ETEC Autoscanning electron microscope. Feeding experiments: Specimens of Mytilus california- nus and M. edulis (Figure 1) were collected intertidally from a single mixed bed in the Ross Islets, Barkley Sound, Vancouver Island, British Columbia. The mussels were ap- proximately equal in size and possessed a mean length of 1.5 cm. To condition the mussels to their feeding aquaria, twenty individuals of each species were placed in two aquaria containing 3.0 L of 0.22 ym Millipore filtered sea- water. The aquaria were maintained at a temperature of 12°C and constantly aerated to insure oxygenation and circulation of the medium. The mussels were considered acclimatized to the aquaria when they had laid down sev- eral byssal anchoring threads; byssal attachment by Myti- _ lus was generally completed within 24 hours. At the onset of the feeding experiments, 500 mL of C- labelled algal exudate were added to each aquarium with one aquarium ‘containing exudate including both dis- solved and particulate organic carbon and the other con- sisting of 0.22 4m Millipore filtered exudate dissolved organic carbon only. Five heat killed contro! animals of each species were then added to each aquarium. At inter- vals of 0.5, 1.5, 3-0, 5.0 and 7.0 hours, 4 live specimens and 1 killed control specimen of each mussel species were re- moved from both aquaria. The gills, mantle and visceral mass were immediately dissected from each mussel and separately dried, weighed and burned in a combustor (Searle Analytic Corp.). The *COz evolved was captured in a 2:3 cocktail of Oxisorb-CO2:Oxiprep-1 (New England Nuclear) and counted for ‘C-activity. To monitor the 44C-activity present in the experimental feeding aquaria, a 2.0mL sample was collected from each aquarium at the Page 278 THE VELIGER Vol. 21; No. 2 4 Mytilus californianus Soba Mytilus edulis @ unfiltered water © 0.22um filtered water 3 100 dp/mg '!C-activity of mantle tissue Ls) Figure 3 Rates of accumulation of '4C-labelled algal exudation material by the mantle tissues of Mytilus californianus and M. edulis. Nota bene: in this figure and those to follow, 0.22 um filtered waters con- tain 1#C-DOC while the unfiltered waters include both '*C-DOC and '4C-POC. Explanation of Figures 1 and 2 Figure 1: The “sea mussel” Mytilus californianus Conrad (left) is distinguished by its thicker shell with 12 radial grooves from the lighter, smooth-valved “bay mussel” Mytilus edulis Linnaeus (right) Figure 2: A scanning electron photomicrograph of the particulate fraction of exudation material released by the “large kelp” Macro- cystis integrifolia Bory. The particulate, light-toned substance is principally algal humic material which has been sloughed from the blade surfaces of the kelp. Tue VELIGER, Vol. 21, No. 2 [FANKBONER, BLAYLOCK & DE Burcu] Figures 7, 2 Vol. 21; No. 2 LS) 100 dp/mg 'sC-activity of gill tissue THE VELIGER Page 279 Mytilus californianus ----- Mytilus edulis @ = unfiltered water © 0.22 ym filtered water control = oO Figure 4 Rates of accumulaion of '4C-labelled algal exudation material by the gill tissues of Mytilus californianus and M. edulis five sampling periods described above and filtered through a Millipore 0.22 xm filter. The dissolved fraction passing through the filter was added to 10 mL of ‘Aquasol’ (New England Nuclear) and counted for *C-activity. The par- ticulate fraction of the sample retained by the membrane filter was combusted, collected, and counted as above. All counts were corrected for background quenching by the external standard method, and were converted to disinte- grations per minute (DPM). Graph data points (Figures 3, 4 & 5) represent mean values (significant at the o.5 level) of *C-activity per unit dry tissue weights. RESULTS Algal exudate: Throughout the seven hour experimen- tal feeding period, C-activity levels of DOC in both aqua- ria remained constant at approximately 10,000 DPM/mL. Page 280 100 dp/mg '4C-activity of visceral mass tissue THE VELIGER Vol. 21; No. 2 Mytilus californianus Mytilus edulis unfiltered water 0.22 um filtered water Figure 5 Rates of accumulaion of '4C-labelled algal exudation material by the visceral mass tissues of Mytilus californianus and M. edulis Particulates collected on Millipore filters also exhibited a uniform level of activity, equivalent to 50 DPM/mL. The ratio of dissolved to particulate “C-activity was there- fore in the order of 2 x 10° : 1, the same order of magnitude as DOC/POC present in natural waters (SHARP, 1973). Scanning electron photomicrographs of particulate car- bon fed to Mytilus revealed that the dominant com- ponent in POC was fibrous plant material (Figure 2) sloughed from blade surfaces of Macrocystis integrifolia during incubation. In addition, the POC included small amounts of diatomaceous material (Skeletonema and Cos- cinodiscus), plus naked dinoflagellates (unidentified). Al- gal exudation material appeared to contain relatively few bacteria; this observation concurs with the results of pre- vious studies (BRYLINSKY, 1977; FANKBONER & DE BURGH, 1977) on exudation by brown macrophytes. Accumulation of “C-activity by Mytilus: The data pre- sented in Figure 3 indicate that mantle tissues in Mytilus edulis accumulate nearly twice the “C-activity in unfil- tered water (DOC & POC) as in filtered water (DOC). Overall, mantle tissues in M. edulis clearly accumulate higher levels of DOC than did M. californianus in either filtered or unfiltered algal exudate. Accumulation of "C-labelled kelp exudation material by the gills of Mytilus edulis was significantly higher than in the case of M. californianus throughout the first five hours of the feeding period (Figure 4). However, a com- Vol. 21; No. 2 parison of the mean values of 'C-activity levels in the gills following seven hours revealed a sudden increase in levels of accumulation of DOC resulting in no significant differ- ences in gill tissue activities between the two mussel spe- cies. Deceleration in rate of DOC accumulation by the gills of M. edulis is consistent with observed activity during di- gestive cycles (LANGTON, 1977) and normal periods of rhythmicity in rates of filtration currents (RAO, 1954; JOR- GENSEN, 1955). Specimens of M. californianus, on the other hand, are not influenced by a rhythm or periodicity in their feeding rates (SEGAL, RAo & JAMES, 1953), and throughout the experiments have uniformly increased *C-activity lev- els in both mantle and gill tissues. In aquaria containing filtered exudation waters (DOC), accumulation of DOC by visceral mass tissues from both mussel species increased steadily throughout the seven hours of the experiment (Figure 5) without any significant differences developing between the two species. However. in aquaria containing unfiltered medium (DOC & POC), Mytilus edulis concentrated “C-activity in the visceral mass to levels approximately one order of magnitude greater than did M. californianus (Figure 5). These results indicate that there exists a difference in particulate feeding efhciency between the two mytilid species. Therefore, dry weights of gills and viscera from each species were aver- aged and compared yielding ratios of gill weights to viscera weights of 0.488 for M. edulis and 0.349 for M. califor- nianus (significant at the o.5 level). Thus it is apparent that in comparison to M. californianus, M. edulis possesses a larger gill in relation to its size. This morphological dif- ference permits M. edulis to filter feed on algal exudate at a higher rate than M. californianus with a consequential increase in the relative *C-activity of its visceral mass. DISCUSSION The data demonstrate that both Mytilus californianus and M. edulis accumulate dissolved and particulate organic carbon exudated by the “‘large kelp’ Macrocystis integri- folia. In our measurements of DOC taken up by mussels, we found that on a ''C-activity to tissue weight basis, M. edulis was generally superior to M. californianus in its ability to accumulate DOC. However, in the case of POC, M. edulis accumulated approximately one order of magni- tude more activity over the same feeding period than did M. californianus. We have concluded that the possession of a larger gill in M. edulis contributes to higher feeding rates and earlier physiological studies on mussel feeding support this contention. For example, JORGENSEN (1955) has shown that filtration rates in juvenile specimens of M. edulis may be 18 to go times greater than for M. califor- THE VELIGER Page 281 nianus. Moreover, the degree of tidal exposure may also affect filtration rates in mussels. Although M. californianus appears to be unaffected by its vertical position in the inter- tidal (SEGAL, RAO & JAMES, 1953), with M. edulis, filtration activity may increase or decrease as a function of intertidal height (JORGENSEN, 1960). Thus, in addition to signifi- cantly superior filtration rates by M. edulis over its ver- tical range as its position becomes higher in the intertidal range, so does its rate of filtration. Interspecific differences in the gill size between Mytilus californianus and M. edulis not only affect competition for food, but in addition, may directly influence their survival in sediment rich waters. A priori, given the same size of mussel, a larger gill would be capable of handling greater amounts of sediment than a smaller one. Therefore, climb- ing ability by M. edulis (HARGER, 1971) may be only one of several factors influencing smothering by sediment mate- rial. In summarizing his investigations of competition be- tween Mytilus edulis and M. californianus, HARGER (1971) has stated that all traits which he considers to be important in competitive interactions between the two mussel species appear to be adaptations to the physical environment. These traits include the heavier shell and greater byssal thread production in M. californianus and the crawling behaviour in juvenile specimens of M. edulis. However, we have concluded that in addition, greater gill size in M. edulis resulting in a superior ability to accumulate dis- solved and particulate organic carbon gives this mussel a significant nutritional advantage over the more physically robust M. californianus. Further, we suggest that in pro- tected sediment-laden waters, a larger gillin M. edulis may - favor its survival over M. californianus. We believe that niche separation in Mytilus should not be interpreted solely upon the basis of mechanical adaptations to physical stress but should include, as well, aspects of the mussels’ physiology. Despite the fact that dissolved and particulate organic carbon is taken up and utilized by a variety of marine in- vertebrates, the over all significance of this food source is not fully understood (see reviews by STEPHENS, 1967, 1968, & 1972; RILEY, 1970; WEsT, DE BURGH & JEAL, 1977). Nearly all previous study on uptake of DOC has evolved around the rate of accumulation of a synthetic substrate(s) by a single species or its tissues. This approach is a sound one because it permits greater control over experimental conditions, but has the disadvantages that food materials for accumulation are not generally available to the organ- ism in aa natural form and under conditions to which the organism would normally be exposed. In this report, we take the position that to determine significance of DOC and POC as a food source for marine organisms, one ap- Page 282 THE VELIGER Vol. 21; No. 2 proach is to use accumulation of naturally occurring or- ganic carbon as a tool to examine specific and existing ecological questions. In doing so, we have shown signif- icant interspecific differences in Mytilus californianus and M. edulis which contribute to niche separation. ACKNOWLEDGMENTS We gratefully acknowledge the support of the National Research Council of Canada, Grant A6966, for making this research possible. Literature Cited BiayLock, WiLiiaAM M. 1978. A morphometric study of shell variation in Mytilus californianus Conrad and Mytilus edulis Linnaeus on the West Coast of Vancouver Island. M. Sc. thesis, Simon Fraser Univ., Burnaby, Brit. Columb., 56 pp. Bry.insky, M. 1977. Release of dissolved organic matter by some marine macrophytes. Mar. Biol. 39: 213 - 220 Cox, C. B., I. N. Hearty « P. D. Moore 1973. Biogeography: an ecological and evolutionary approach. John Wiley & Sons. New York. 179 pp. Dorey, A. E. 1965. The organization and replacement of the epidermis in acoelous turbellarians. Quart. Journ. Micr. Sci. 106: 127 - 142 FANKBONER, PETER VAUGHN , 1976. Accumulation of dissolved carbon by the solitary coral Balano- phyllia elegans — an alternative nutritional pathway? in: Coel- enterate ecology and behaviour, G. O. Mackie, ed. Plenum Publ. Corp. New York; pp. 111 - 116 ‘ FANKBONER, PeTerR VAUGHN & Louis D, DruEHL 1976. In situ accumulation of marine algal exudate by a polychaete worm (Schizobranchia insignis). Experientia 32: 1391 - 1392 FANKBONER, PETER VAUGHN & MAUuREEN E. pe BurGH 1977. Diurnal exudation of '4C-labelled carbon compounds by the large kelp Macrocystis integrifolia Bory. Journ. Exp. Mar. Biol. Ecol. 28: 151 - 162 Hammon, C. S. « P. J. OsBorne 1959. | Carbon dioxide fixation in marine invertebrates: a survey of major phyla. Science 130 (3386): 1409-1410 (20 November 59) Harcer, JoHN Rosin E. 1968. The role of behavioral traits in influencing the distribution of two species of sea mussel, Mytilus edulis and Mytilus californianus. The Veliger 11 (1): 45-49; 3 text figs. (1 July 1968) 1972. Competitive co-existence: maintenance of interacting associa- tions of the sea mussels Mytilus edulis and Mytilus californianus. The Veliger 14 (4): 387-410; 8 text figs. (1 April 1972) Jounson, Myrtve ExvizaBetH « Harry JAMES SNOOK 1927. Seashore animals of the Pacific coast. MacMillan Co., New York; 659 pp.; 700 figs. JorcEeNsEN, G. B. 1955; Quantitative aspects of filter feeding in invertebrates. Biol. Rev. 30: 391 - 454 : ‘ 1960. Efficiency of particle retention and rate of water transport in undisturbed lamellibranchs. LancTon, R. W. 1977. Digestive rhythms in the mussel Mytilus edulis. 41: 53-58 Morton, Joun Epwarp 1967. Molluscs. London, Hutchinson Univ. Library, 244 pp.; 41 figs. NicHotson, Nancy L. & WiLuiam R. Briccs 1972. Translocation of photosynthate in the brown alga Nereocystis. Amer. Journ. Bot. 59: 97 - 106 Peguicnar, E. 1973. A kinetic and autoradiographic study of the direct assimilation of amino acids and glucose by organs of the mussel Mytilus edulis. Mar. Biol. 19: 227 - 244 Rao, K. P. 1954. Tidal rhythmicity of rate of water propulsion in Mytilus, and its modifiability by transplantation. Biol. Bull. 106: 353 - 359 Ricketts, Epwarp F. & Jack Cavin 1952. Between Pacific tides. v- xlli+3 - 502; 46 pits. Rivey, Gorpon A. 1970. Particulate organic jmatter in seawater. 1-118 Scumirz, Kraus & Lait M. SrivASTAVA 1974a. On the fine structure of sieve tubes and the physiology of assimilate transport in Alaria marginata Postels « Ruprecht. Canad. Journ. Bot. 53: 861 - 876 1974b. he enzymatic incorporation of 32P into ATP and other organic compounds by sieve tube sap of Macrocystis integrifolia Bory. Planta 116: 85 - 89 Seca, E., K. P Rao «& T. W. James 1953. Rate of activity as a function of intertidal weight within popu- lations of some littoral molluscs. Nature 172: 1108 - 1109 SHarp, J. H. 1973. Size classes of organic carbon in seawater. 18: 441 - 447 SreBuRTH, JoHN MCN. 1969. Studies on algal substances in the sea. III. The production of extracellular matter by littoral marine algae. Journ. Exp. Mar. Biol. Ecol. 3: 290 - 389 S1rEBURTH, JoHN MCN. & A. JENSEN 1968. Studies on algal substances in the sea. I. Gelbstoff (humic mate- rial) in terrestrial and marine waters. Journ. Exp. Mar. Biol. Ecol. 2: 174 - 189 STEPHENS, Grover C. 1967. Dissolved organic material as a nutritional source for marine and estuarine invertebrates. in: Estuaries, G. H. Lauff, (ed.), AAAS, Washington, D. C.: 367 - 373 Journ. Conseil. 26: 49 - 116 Mar. Biol. Stanford Univ. Press, Stanford, Calif. Adv. Mar. Biol. 8: Limnol. Oceanogr. 1968. Dissolved organic matter as a potential source of nutrition for marine organisms. Amer. Zool. 8: 95 - 106 1972. Amino acid accumulation and assimilation in marine organisms. Campbell « Goldstein (eds.), Academic Press, New York: 155-174 STEPHENS, Grover C. & R. A. SCHINSKE 1961. Uptake of amino acids by marine invertebrates. Oceanogr. 6: 175-181 West, A. B., Maureen E. pe Burcu & F. Jeav in press Dissolved organics in the nutrition of benthic invertebrates. Proc. 11th Europ. Mar. Biol. Symp. (1976) Wricut, S. H. , f 1976. Isolated gills as a system for the study of amino acid uptake by Mytilus. Amer. Zool. 16: 237 Limnol. Vol. 21; No. 2 THE VELIGER Page 283 Studies on the Mytilus edulis Community in Alamitos Bay, California: VII. The Influence of Water-Soluble Petroleum Hydrocarbons on Byssal Thread Formation ROBERT SCOTT CARR' anp DONALD J. REISH Department of Biology, California State University Long Beaach, Long Beach, California 90840 INTRODUCTION Mytilus edulis, Linnaeus, 1758. 1s the predominant organ- ism associated with docks. pilings. and boat floats in Ala- mitos Bay (REIsH. 1964a). Occasionally red tide blooms decimate the M. edulis population as well as the diverse assemblage of polychaetes. amphipods, and other fauna which comprise the M. edulis community (REISH, 196.44, 1964b). It is not known whether the mussels were affected directly by an accumulation of a toxic substance secreted by the dinoflagellates or indirectly by the decrease of dis- solved oxygen in the water due to bacterial decomposition of organic material. A drastic reduction in byssal thread production was observed under laboratory conditions for M. edulis exposed to dissolved oxygen concentrations be- low 0.9 ppm (REISH & AYERS. 1968), which is higher than the 0.1 ppm observed in Alamitos Bay during the 1962 red tide. It seems logical to assume that byssal thread production is a reasonable parameter with which to gauge the meta- bolic activity or physiological functioning of Mytilus edu- lis. The ability of M. edulis to form byssus attachments 1s crucial to the survival of this organism. Martin ef al., (1975) have shown that byssal thread production may be used as an indicator of the dose response to heavy metal toxicants. Due to the activity of motor powered vessels within the Alamitos Bay area, petroleum hydrocarbons are a pollut- ant with which the Mytilus edulis community must con- tend. The purpose of this present investigation was to ' Present address: Department of Biology. ‘Texas A&M University. College Station, TX 77843 determine what effect the water-soluble fraction of three different oils had on the capacity of M. edulis to form byssal threads in the laboratory. MATERIALS anp METHOD Mytilus edulis specimens were collected from boat docks in Alamitos Bay during the month of July. Only mussels from 18 to 23 mm in width were used. Limiting specimens to this size range insured that no gravid individuals would be included. GLaus (1968) showed that small M. edulis produce more byssal threads than do larger ones under optimum conditions. Several hundred mussels of the ap- propriate size were acclimated at 19.5 + 0.5° C for three days. Prior to the start of the experiment, the valves were scraped clean of fouling organisms and all byssal threads were cut. Two of the oils used in this study were South Louisiana crude oil and No. g fuel oil which were originally supplied by the American Petroleum Institute and redistributed by Dr. Jack W. Anderson of Texas A&M University. A com- mercially available oil, Sta-lube 50:1 2 cycle outboard mo- tor oil was also tested. The procedure for preparation of the water-soluble fraction (WSF) of the oils was similar to the method employed by ANDERSON et al., (1974a). Nine parts millipore filtered (0.45 zm) seawater was stirred with one part oil on a magnetic stirrer for 20 hours at a slow speed. After stirring, the aqueous phase was siphoned off and utilized immediately in experiments. A detailed liq- uid-gas chromatographic analysis of the two API reference oils and their WSFs was carried out earlier by Dr. J. Scott Page 284 Warner, Battelle Memorial Laboratories (ANDERSON et al., 1974). All experiments were conducted at 19.5 -- 0.5° C with millipore filtered (0.45 zm) seawater. The bioassay con- tainers employed were 500mL Erlenmeyer flasks. Each flask contained 100mL of the appropriate test solution with one mussel per flask. Concentrations of 25,50, 75, and 100% of the initial WSF were tested for each of the three oils. The solutions were not changed or replenished dur- ing the course of the experiment. No food was adminis- tered throughout the duration of the experiment. Byssal thread production and survival were observed at 1, 2, 3, 4, 7, and 14 days. Because the data did not conform to analysis by parametric techniques, the non-parametric ranking test of Mannand Whitney was utilized to determine significant differences in byssal thread production. RESULTS The influence of the WSFs of South Louisiana crude oil, No. 2 fuel oil and Sta-lube outboard motor oil are pre- sented in Tables 1, 2, and 3, respectively. Byssal thread production was significantly inhibited at the 100% WSF for all three oils. For South Louisiana crude oil and No. 2 fuel oil this inhibitory influence was significant through- out the duration of the experiment. For the Sta-lube out- board motor oil the inhibition of byssal thread production was only significant up until the 72 hour check. South Louisiana crude oil was most effective in its inhibitory in- fluence on a percent WSF basis while the Sta-lube out- board motor oil produced the least effect. An unexpected result of this experiment was that a sig- nificant enhancement in byssal thread production was ob- served for all three WSFs at concentrations below those at which an inhibitory effect was elicited. At 96 hours a sig- nificant enhancement was observed at 25% of the WSF for South Louisiana crude and No. 2 fuel oil while 50% of the WSF of Sta-lube outboard motor oil produced a similar stimulation as compared with the control. In a repeat ex- periment, 25% WSF of No. 2 fuel oil produced a fourfold increase in byssal thread production as compared with the control after 96 hours of exposure. This stimulation of byssal thread formation, however, was not significant be- yond 96 hours for any of the three WSFs. > DISCUSSION The WSF of South Louisiana crude oil and No. 2 fuel oil have been analyzed by UV and IR spectrophotometry and THE VELIGER Vol. 21; No. 2 were shown to contain 19.8 mg/L and 8.7 mg/L total hy- drocarbons, respectively (ANDERSON et al., 1974a). Of the hydrocarbons in the No. g fuel oil WSF, approximately 39% are aromatic compounds as compared to less than 2% aromatics for the WSF of South Louisiana crude oil. The soluble aromatic and naphthalene compounds of an oil produce the majority of its toxic effect (ANDERSON et al., 1974b). These compounds are highly volatile, however, as the naphthalene compounds have been observed to reach undetectable levels under similar bioassay conditions after g6 hours (Carr & REIsH, 1977). The higher molecular weight (> Cio) water-soluble paraffinic hydrocarbons are not nearly as volatile as the aromatic ones (Dopp, 1974), and hence their relative percentage of the total hydrocar- bons present in solution increases with time. An examination of Tables 1 and 2 indicates that South Louisiana crude oil was the most effective inhibitor of bys- sal thread production on a percent WSF basis. Since the WSF of South Louisiana crude oil contains the highest concentration of paraffinic hydrocarbons, which are the least volatile of the water-soluble hydrocarbons, it appears likely that these higher molecular weight (> Cio) aliphatic compounds are at least partially responsible for the chronic inhibition of byssal thread formation. In the two refined oils, whose WSFs contain a higher percentage of volatile aromatics, the suppression of byssal thread formation was not nearly as marked. Other studies have shown the WSF of No. 2 fuel oil to be more toxic than South Louisiana crude oil on a percent WSF and total initial hydrocarbon basis for a variety of marine organisms (ANDERSON e¢ al., 1974; Rossi et al., 1976; CARR & REISH, 1977).In the present study at 14 days the 100% WSF crude oil group suffered 40% mortality whereas in the 100% WSF of the No. 2 fuel oil only 20% mortality was observed. These were the only deaths occur- ring during the course of the experiment. While this dif- ference in survival rates is not statistically significant, the relative mortality rate follows the trend seen in suppres- sion of byssal thread production. Again, the most delete- rious effects were produced by the WSF of South Louisiana crude oil. It appears that unlike most of the other marine organisms which have been tested that Mytilus edulis is more susceptible to contamination by crude oil than by these refined oils. The unanticipated result of a statistically significant stimulation by byssal thread production was observed for all three WSFs up until 96 hours after which time the stimulatory effect although evident was not significant sta- tistically. When considering the changes in hydrocarbon composition occurring in the WSF over a 96 hour time Vol. 21; No. 2 THE VELIGER Page 285 Table 1 Influence of Seawater-Soluble Fraction (WSF) of South Louisiana Crude Oil on Byssal Thread Production of Mytilus edulis. Tests for Statistical Observations and Significance. Palit Pie 1 24 hours 48 hours 72 hours | 96 hours e 7 days 14 days Average Average Average hess | Average Average Experimental No. of No. of No. of | No. of | No. of | No. of Concentrations Byssal U! Byssal U | Byssal U | Byssal U | Byssal U__; Byssal U as Percent WSF Threads Threads | Threads | Threads | Threads | Threads 3 s | eae seal Pane Control 5.75 = 9.85 = | 12.6 = | 15.55 = 28.4 = | 39.15 = n= 20 ! : | : 25 8.2 123.5 17.3 1502 1816 133 | 24.6 146.5° | 42.3 130 58.6 131.5 n=10 50 2.5 137 Gl 126.5 5.7 146° 8.2 133.5 12.0 13125 ee eee ole 125.5 n= 10 | | | 75 1.1 159.5% 3.2 151.53 3.4 1.54 | 3.9 Wa sh 7s) 163.53 15.2 150.53 n= 10 | | | 100 0 1853 0.1 193? 0.1 193 | 0.1 1993 1.4 IG 7 | 4.] 177.53 n=0 ? | | 'Mann-Whitney U statistic comparing experimental populations with the control. U statistic at .05% level of significance = 138. *Significant increase in byssal thread production. Significant decrease in byssal thread production. Table 2 Influence of Seawater-Soluble Fraction (WSF) of No. 2 Fuel Oil on Byssal Thread Production of Mvtilus edulis. Tests for Statistical Observations and Significance. 24 hours 48 hours 72 hours 96 hours | 7 days 14 days (a H oe eee . Average Average , Average Average | Average Average Experimental | No. of | No. of _ No. of No. of | No. of No. of Concentrations | Byssal U* | Byssal U | Byssal U Byssal U Byssal U Byssal U as Percent WSF Threads Threads Threads Threads Threads Threads Control Soy = ascii? Weleneg) yess ine = 28 /4te ie SOn15 We n = 20 | | 25 13.3 132.5 24.8 146.55 | 29.4 144° 43.2 144° 47.2 133.5 57.3 134 n= 10 50 3.3 131.5 9.0 102 | 13.4 106.5 18.5 123.5 31.3 108 37.2 120 n= 10 | | | 75 ; OS 178.58 8.8 106.5 11.4 102.5 15.8 102.5 25.3 100.5 39.1 101.5 n= 10 | | 100 0 Ie OL 1975) {012 190.5® 2.8 178° 6.8 161.5° 16.1 148° ‘Mann-Whitney U statistic comparing experimental populations with the control. U statistic at .05% level of significance = 138. ‘Significant increase in byssal thread production. ®Significant decrease in byssal thread production. Page 286 period. the evaporation of the volatile aromatics and naph- thalenic compounds. particularly, is the most predominate change. The stimulation of byssal thread formation de- creases at approximately the same time that the naphtha- lenic compounds reach undetectable levels in the WSF, lending credence to the possibility that these aromatic and polyaromatic compounds may be responsible for this ob- served stimulatory effect. Additional tests with specific aromatic and naphthalenic compounds would further elu- cidate this hypothesis. Most likely there is no specific hydrocarbon that is causing this effect but rather a combi- nation of compounds which is responsible. This is not the first time that exposure to low-level water-soluble hydrocarbons has produced a stimulation of some physiological process in marine organisms. NEFF et al., (1976) observed an increased growth rate with zoea of the mud crab Rhithropanopeus harrisii exposed to sub- lethal concentrations of No. 2 fuel oil. TATEM (1975) ob- served an increase in the number of larvae produced in the grass shrimp Palaemonetes pugio when exposed to sub- lethal WSFs of No. 2 fuel oil. Rossi (1976), conducting an investigation through several generations with the poly- THE VELIGER Vol. 21; No. 2 chaete Neanthes arenaceodentata, observed a decrease in oocyte maturation as compared with the control for all ex- posure concentrations. Reproduction was significantly stimulated in the polychaete Ophrytrocha diadema ex- posed to an initial total hydrocarbon concentration of 1.99 ppm of South Louisiana crude oil (Carr & REISH, 1977). Similar phenomena have been observed in toxicity tests with rats and mice (SMYTH, 1967). Smyth suggests that the increased growth and reduced mortality observed in tox- icity tests with low levels of known noxious substances is due to the exercising of homeostatic mechanisms. It seems likely that a similar phenomenon is occurring in some marine animals exposed to water-soluble hydrocarbons. When considering the results of these experiments and how they relate to the natural environment, it is worthy of noting that the type of water-soluble hydrocarbons most commonly entering the harbor waters (outboard motor fuel) produces the least inhibition of byssal thread produc- tion. Since M. edulis characteristically inhabits floating boat docks near the air-water interface, these mussels would be exposed to a greater threat than that posed by water- soluble hydrocarbons were a large oil spill to take place Table 3 Influence of Seawater-Soluble Fraction (WSF) of Sta-lube Outboard Motor Oil on Byssal Thread Production of Mvtilus edulis. Tests for Statistical Observations and Significance. 24 hours 48 hours 72 hours 96 hours 7 days 14 days + — a Average Average Average \ Average | Average | Average Experimental No. of No. of ' No. of ' No. of No. of No. of Concentrations Byssal 107 Byssal U Byssal iC" _ Byssal iC Byssal U | Byssal IC as Percent WSF Threads Threads Threads | Threads Threads ‘Threads ag I a AE ST Control 473 = Pe oe ein cm a enn n = 20 H 25 10.0 132 14.8 122.5 16.6 120.5 | 20.8 116.5 26.5 104 | 28.8 106 ny l0 H 50 16.3 1428 21.4 1408 25.9 1428 31.8 1388 . 39.1 125 | 48.8 118.5 n= 10 | ! | | 75 2.8 123 8.7 113 ek 115 ; 18.1 101.5 | 23.2 104.5 | 28.1 113 n= 10 100 1.0 1719 4.2 1539 | 4.5 1549 10.2 135 22.2 104 | 27.4 109.5 | | | 7Mann-Whitney U statistic comparing experimental populations with the control. U statistic at .05% level of significance = 138. *Significant increase in byssal thread production. *Significant decrease in byssal thread production. Vol. 21; No. 2 THE VELIGER Page 287 locally. Their proximity to the air-water interface would allow floating oil to strand on these mussels causing physi- cal smothering under extreme conditions. Although not as dramatic, chronic exposure to sublethal water-soluble hy- drocarbons might also lead to the decline or eradication of a population in a less conspicuous manner. The results of this study suggest that the levels of water- soluble hydrocarbons currently found in Long Beach Har- bor due to motor boat activity pose little threat to the survival of Mytilus edulis. The levels of water-soluble hy- drocarbons necessary to cause deleterious effects would only be found associated with a local spillage of oil. Certain areas receiving chronic low level hydrocarbon insult may not be suitable for survival of M. edulis. Barring the event of any local oil spills, M. edulis population levels are more dependent on the periodic red tide phenomenon than the effects resulting from local motor boat usage. Why low water-soluble hydrocarbon levels produce stimulation of byssal thread production is a question which awaits further investigation. SUMMARY 1. The bay mussel Mytilus edulis was exposed to varying concentrations of the water-soluble fraction (WSF) of No. 2 fuel oil, South Louisiana crude oil and Sta-lube outboard motor oil and the number of byssal threads produced was recorded at intervals over a 14 day period. no Byssal thread production was significantly inhibited at the 100% WSF for all three oils. 3. South Louisiana crude oil was the most effective in its inhibitory influence ona percent WSF basis while the Sta-lube outboard motor oil produced the least effect. 4. An unexpected result of this experiment was that a significant enhancement in byssal thread formation was observed for all three WSFs at concentrations be- low those at which an inhibitory effect was elicited. Literature Cited ANDERSON, Jack W, Jerry M. Nerr, Bruce A. Cox, Henry E. TATEM, & G. MicHaeL HicHToweRr 1974a. Characteristics of dispersions and water-soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish. Mar. Biol. 27: 75 - 88 1974b. The effect of oil on estuarine animals: toxicity, uptake and de- puration, respiration. pp. 285-310 in: F J. Vernberg & W. B. Vern- berg (eds.), Pollution and physiology of marine organisms. Acad. Press, New York Carr, Rospert Scott «& Donatp J. Reisu 1977. The effect of petroleum hydrocarbons on the survival and life history of polychaetous annelids. pp. 168-173 in: D. A. Wolfe (ed.), Fate and effects of petroleum hydrocarbons in marine ecosystems and organisms. Pergamon Press, New York Dopp, E. N. 1974. Oils and dispersants. pp. 3-9 in: L. R. Beynon « E. B. Cowell (eds.), Chemical considerations, ecological aspects of toxicity testing of oils and dispersants. Halstead Press, New York Graus, Karen J. 1968. Factors influencing the production of byssal threads in Mytilus edulis. Biol. Bull. 185: 420 Martin, James M., Frep M. Pittz & Donatp J. ReisH 1975. Studies on the Mytilus edulis community in Alamitos Bay, Cali- fornia. V. The effects of heavy metals on byssal thread production. The Veliger 18 (2): 183-188; 6 text figs. (1 October 1975) Nerr, Jerry M., Jack W. ANDERSON, Bruce A. Cox, Ray B. Lavoxun, Jr., Steven S. Rossi » Henry E. TaTemM 1976. Effect of petroleum on survival, respiration and growth of marine animals. pp. 515-539 in Symposium on sources, effects and sinks of hydrocarbons in the aquatic environment. Amer. Inst. Biol. Sci., Washington, D. C. ReisH, Donatp J. 1964a. Studies on the Mytilus edulis community in Alamitos Bay, Cali- fornia: I. Development and destruction of the community. The Veliger 6 (3): 124-131; 1 map; 4 text figs. (1 January 1964) 1964b. Studies on the Mytilus edulis community in Alamitos Bay, Cali- fornia: II. Population variations and discussion of the associated organ- isms. The Veliger 6 (4): 202-207; 3 text figs. (1 April 1964) ReisH, Donatp J. # JosepH L. Ayers, Jr. 1968. Studies on the Mytilus edulis community in Alamitos Bay, Cali- fornia: III. The effects of reduced dissolved oxygen and chlorinity concentrations on survival and byssal thread production. The Veliger 10 (4): 384-388; 2 text figs. (1 April 1968) Rossi, Steven S. 1976. Interactions between petroleum hydrocarbons and the polychaet- ous annelid Neanthes arenaceodentata: effects on growth and reproduc- tion; fate of diaromatic hydrocarbons accumulated from solutions or sediments. Ph. D. dissertation, Texas A&M Univ., College Station, Texas, 95 pp. Rossi, Steven S., Jack W. ANDERSON & G. Scotr Warp 1976. Toxicity of water-soluble fractions of four test oils for the poly- chaetous annelids, Neanthes arenaceodentata and Capitella capitata. Envir. Poll. 10: 9 - 18 Smytu, H. F, Jr. 1967. Sufficient challenge. Tatem, Henry E 1975. The toxicity and physiological effects of oils and petroleum hydrocarbons on the estuarine grass shrimp Palaemonetes pugto Holt- hius. Ph. D. dissertation, Texas A&M Univ., College Station, Texas; 194 pp. Fd. Cosmet. Toxicol. 5: 51 - 58 Page 288 THE VELIGER Vol. 21; No. 2 Distributional Patterns of Juvenile Mytilus edulis and Mytilus califormanus PETER S. PETRAITIS Department of Biology, California State University, San Diego, California 92182 INTRODUCTION Mytilus edulis Linnaeus, 1758 and Mytilus californtanus Conrad, 1837 are two species of mussels which occur on the west coast of North America. Mytilus edulis is com- monly found in bays and on semi-exposed coasts while Mytilus californianus is found only on exposed coasts (HarGER, 1967). Association of these species is assumed to be spurious since M. edulis and M. californianus are so similar. It has been suggested this coexistence is main- tained by storms and selective predation which contin- ually provide new surfaces for recolonization (HARGER & LANDENBERGER, 1971; HARGER, 1972). In quiet bays, Mytilus californianus’ exclusion has been attributed to physiological and competitive factors. The physiological inability of larval M. californianus to with- stand salinity stress has been proposed as a possible deter- minant of exclusion (YOUNG. 1941). A very wide range of salinity tolerance has been shown for larval M. edulis (BAYNE, 1965). HARGER (1968) suggests that exclusion of Mytilus cali- fornianus is caused by the upward crawling behavior of M. edulis which smothers the less mobile M. californianus under accumulating silt and pseudofeces. In bays with swift currents, less silt accumulates and M. californianus is found (HARGER, 1972). However, there are several aspects of the distribution of Mytilus californianus which cannot be fully explained by either competitive or physiological factors. First, M. cali- fornianus is often not even found in bays of normal salinity (e.g. MAcGINITIE, 1935). Second, Harger assumes M. cali- fornianus cannot compete after settling, yet shells of juve- nile M. californianus are not found within mussel clumps from bays (PETRAITIS, 1974). Finally, settlement studies in bays never report juvenile M. californianus even on clean surfaces without M. edulis (e.g. GRAHAM & GAY, 1945; REIsH, 1964). Present address: Department of Ecology and Evolution, State Uni- versity of New York, Stony Brook, N. Y. 11794 Ifa population of a species is being held below the carry- ing capacity of the environment because of another species, there is a selective advantage to any gene which reduces or eliminates this sharing of resources (COLE, 1960). It would seem probable that the partition of the available space by Mytilus edulis and M. californianus can be explained by this hypothesis. Both species are known to settle selectively. Mytilus edulis sets sequentially, first on filamentous algae and then into adult clumps (BAYNE, 1964). Without noting whether settlement is primary or secondary, small M. edulis have been found along the byssal threads of adults (SEED, 1969; DayTON, 1971), on a variety of algae (COLEMAN, 1940; DEBLOK & GREELEN, 1958; SEED, 1969) and on newly ex- posed surfaces (Moore, 1939). M. californianus have been reported to settle on barnacles (DayTON, 1971), on old mussel shells (YOUNG, 1946) and on newly exposed surfaces (SHELFORD et al., 1935). Work was undertaken to clarify whether or not the spe- cies’ differences in juvenile mussel distributions exist and if these differences could account for the known differ- ences in adult distributions. METHODS All work was done at Crystal Pier in Pacific Beach and on a floating dock in Mission Bay unless otherwise stated. Both locations are in the San Diego, California area. Distributional differences were examined by sampling twenty-six quadrats. Sampling was done by scraping off all mussels within a square which was approximately 56 square centimeters. Mussels were sorted by species and size. Since Mytilus edulis can grow to 7 mm in one month (Coe, 1945) and M. californianus to 4mm in one month (CoE & Fox, 1942), mussels under 5 mm were designated as juve- niles. Three of the samples were taken from the north jetty at the entrance of Mission Bay. Sampling dates, locations, and the number of adult and juvenile mussels per sample are given in Table 1. Vol. 21; No. 2 THE VELIGER Page 289 nn —— ————___————————— Juvenile differences in distribution were also examined by nearest neighbor methods. Pilings at Crystal Pier were chosen at random from those that could be reached at low tide. Sampling was done on July 2 and 3, August 16 and 24, September 15 and October 13, 1973. The September fifteenth data were taken at Scripps Institution of Ocean- ography Pier. A plumb line was placed on each piling. The species of all juvenile mussels that intersected the line and Table 1 Date. location and number of mussels per quadrat. Spearman rank correlations between abundances are given. Letters J denote juveniles: A. adults; Me. Mytilus edulis; and M.c.. Mvtilus californianus. *P < 0.01. i Number ot Location and Date AMLe. JMoe. AMLe. JM.uc. Mission Bay Jetty 1] 4 24 8 June 18. 1973 64 31 59 19 40 2 37 3 Crystal Pier 51 37 20) 14 June 18, 1973 73 2) 10 5 Crystal Pier () ) 53 27 July 2, 1973 64 12 35 10 58 i) 23 7 Crystal Pier 36 14 1] ] July 4. 1973 43 19 10 2 Crystal Pier 0 0) 23 0 December 9. 1973 1 0 37 25 l 0 12 6 52 2 29 6 44 7 35 10 0 0 82 28 0 21 4 44 3 1] 0 45 2 18 4 38 1 2 0 0 0 31 0 2 0 42 15 0 0) 11 0 15 1 6 0 0 0 0 0 0 0 0 0 Correlation coefficients AM.e. JM.e. AMic. JM.c. AM.e. 0.880* 0.045 0.259 JM.e. —0.009 0.272 AM.c. 0.706* the species of the next nearest mussel were recorded. Data collected after July 3, 1973 included the size of the nearest neighbor and the surface to which the juvenile mussel was attached. In order to determine the relative abundance of sub- strate types, points along the plumb line were chosen at random. The surface type at each point and size of the nearest mussel were noted. These data were collected on February 8, 1974. To test for the effects of adult mussels on settlement be- havior, plastic ice cube trays with transplanted mussels were placed on the exposed coast and in the bay. The first experiment was conducted from July 6, 1973 to October 27, 1973. Five mussels of either species were placed in each cube. Four cubes were allocated for each of the three treat- ments: pure Mytilus californianus, pure M. edulis, and no mussels. Trays were covered with Varathane coated 0.63 cm (4 inch) mesh. Trays on the exposed coast were posi- tioned at the mean tide level. Trays in the bay were sus- pended from a floating dock, 30cm below the surface. At the end of the experiment, juveniles present were counted. A second experiment was conducted from October 28, 1973 to March 6, 1974. In this experiment, seven mussels per cube and eight cubes per treatment were used. RESULTS Quadrat samples were analyzed by Spearman rank corre- lation. The number of juvenile Mytilus edulis per quadrat is correlated with the number of adult M. edulis per quad- - rat. Number of juvenile and adult M. californianus are also correlated. All other comparisons show no significant correlations (see Table 1). Nearest neighbor data were tested by two way G test of independence (SOKAL & ROHLF, 1969). Analysis shows oc- currence of juveniles depends on the presence of the same species (Table 2). For 129 of the 153 observations in Table 2, the juvenile is touching its nearest neighbor. The choice of substrate also depends on the species of the juvenile. Juvenile Mytilus californianus are found almost exclu- sively on M. californianus, while juvenile M. edulis are found on all types of surfaces. Goodness of fit tests of the juveniles’ utilization of sub- strate against the frequency of available substrate show a poor fit for both species (see Table 3, random point com- parisons). Neither species settles randomly. From the random point data, the mean length of the Mytilus edulis population (2.3 + 0.30cm) and of the M. californianus population (3.1 = 0.77 cm) were estimated. Page 290 THE VELIGER Vol. 21; No. 2 Table 2 Nearest neighbors of juvenile mussles on the exposed coast. Words in parentheses indicate relative levels of mortality observed by Harcer (1967). *P < 0.01. G denotes the G statistic (SOKAL AND ROHLF, 1969). Nearest neighbor G M.e. M.c. Base point 56 (Low) 9 (Low) 6 (High) 82 (High) Juvenile Mvtlus edulis Juvenile Mvtilus californianus 106.1* Table 3 Comparison of substrate preferences of juvenile mussels on the exposed coast. Organisms in the ‘other’ column are predominantly barnacles. *P < 0.01. Degrees of freedom are denoted by df. Substrate utilized } Other Base point Bat Living Clear M.e. M.c. Organisms Surface Juvenile Mytilus edulis 1] 5 20) 13 Juvenile Mytilus californianus ] 40 5 23 Random point 8 30 12 16 Comparison df G Mytilus edulis versus Mvtilus californianus 3 49.81* Mytilus edults versus random point 3 33.31* Mytilus californianus versus random point 3 20.66* A t-test of the mean length of the M. edulis population against the mean length of the M. edulis nearest to a juve- nile M. edulis (0.8 + 0.14 cm) shows significant differences (P 170.9 = 32.8 (n = 20) (n = 20) two eges/capsule TOM) ZENS 14.822 5:4 2025 258 (n = 20) (n = 20) three eges/ 74.3 = 1.8 230.9 x 216.4 capsule (n = 3) (n = 1) numbers of eggs per capsule, and capsule size increased (Table 3). Shell lengths of newly-hatched veligers did not vary with temperatures between g°C and 24°C; however, develop- ment took longer at lower temperatures (Table 4). Aver- Table 4 Relationship between IT°C and development time in Elvsia chlorotica WE days to hatching 20° - 24° 6 13° - 15° 8-9 g° - 12° 12 age shell lengths varied slightly among samples of veligers from g different egg masses allowed to develop at 20°-24°C: 138.5 4.4m, 126.0 5.2um, and 132.4 + 4.5 um,n—= 35 each sample. The veliger shell was unsculptured and belonged to Thompson's Type 1 (THompson, 1961). No chloroplasts were detected by microscopic examina- tion in either the eggs or the newly-hatched veligers of Elysia chlorotica. GREEN (1968) did not find chloroplasts in the egg mass of Elysia hedgpethi. He suggests that chlo- Explanation of Figures 1 to 3 Figure 1: Adult Elysia chlorotica Figure 2: Cast larval shell and operculum of Elysia chlorotica Figure 3: Newly metamorphosed juvenile of Elysia chlorotica Tue VELIGER, Vol. 21, No. 2 [HarRIGAN & ALKoN] Figures 1 to 3 Figure 1 Vol. 21; No. 2 roplasts are taken up anew by each generation (GREEN, 1970). If E. chlorotica has functional chloroplasts the juve- niles must obtain them when they begin to feed on fila- mentous algae. Veligers swam at the surface for the first 10 days post- hatching. Statocysts were present at hatching and eyes ap- peared on days 5 and 6. Newly-hatched veligers were characterized by a row of black spots in the mantle edge around the shell aperture. From day g a band of black spots began to spread from the base of the shell aperture dorsally. By days 12-14 the spots had spread and coalesced, so that the entire veliger. including the foot, appeared black. This pigment always appeared near maximum shell length, 240 jum. No veliger was observed to metamorphose before the body had entirely darkened. Seventy percent of the veligers attained a shell length at which metamorphosis (212 zm) could occur by day 12 post-hatching. Pigmentation devel- opment was complete within 2 to 3 more days. LARVAL REARING EXPERIMENT 1: Seventy-six percent of veligers survived to day 14 post- hatching in two plates containing initially fifty larvae each. Day 14 veligers were exposed to a variety of materials from the adult habitat: a primary film grown from marsh detri- tus, filamentous green algae, adult mucus, and adults. On day 28 post-hatching 1 veliger metamorphosed on a pri- mary film. Metamorphosis took 2 days to complete; first the velum was resorbed, then about 24 hours later the shell and operculum were cast (Figure 2), resulting in a rapid- ly moving, black worm-like juvenile which lacked both tentacles and parapodia (Figure 3). On day 42 post-hatching half the remaining larvae (n—37) were exposed toa 0.1% solution in MPF seawater of the neuromuscular blocking agent succinylcholine chlo- ride (Sigma Chemical Co.) ina filmed plate. Bonar (1976) successfully used this compound to induce metamorphosis in the nudibranch Phestilla sibogae Bergh, 1905. The mechanisms of action of this chemical are unknown in in- vertebrates. Between days 46-55, post-hatching 60.6 of the veligers metamorphosed in the succinylcholine chloride solution as opposed to none ina filmed plate with seawater alone. LARVAL REARING EXPERIMENT 2: One out of 55 veligers which survived to day 16 post- hatching metamorphosed on a primary film, prior to any experimental manipulations. Based on growth rate at 20°- 24°C and rate of development of pigmentation in veligers, 16 days is probably the earliest that metamorphosis might occur in the field at summer water temperatures. THE VELIGER Page 303 Day 16 post-hatching veligers (n—=54) were divided into 3 equal groups. The first group was placed in seawater alone, the second in seawater containing 2mLs of aseawater extract of filamentous algae from the adult habitat, and the third in a seawater solution of 0.1% succinylcholine chlo- ride. All 3 plates had a primary film; the larvae were fed unicellular algae. By 23 days post-hatching 10 of 18 veligers had metamorphosed in the succinylcholine chloride solu- tion, but none in either of the other 2 conditions. On day 23 all remaining veligers were placed in succinylcholine chloride, resulting in a total of 42.4% metamorphosis in that sample of veligers exposed to the chemical. Length of shells cast at metamorphosis ranged from 211.9 pm to 226.1 wm. Lengths of the extended juveniles ranged from 350-450 um. No morphological differences were noted between juveniles which metamorphosed with and without succinylcholine chloride. Based on the initial sam- ple of 100 veligers in experiments 1 and 2, total metamor- phosis was 15-20%. Research is currently in progress to find the natural in- ducer of metamorphosis 1n Elysia chlorotica, as well as to establish rearing techniques for both E£. chlorotica and Haminoea solitaria. SUMMARY anp CONCLUSIONS 1. The cephalaspid Haminoea solitaria and the sacoglos- san Elysia chlorotica have been reared through meta- morphosis in the laboratory. 2. Haminoea solitaria metamorphoses in response to a primary film grown from sediments collected in the adult habitat. Veligers begin to metamorphose after 20 days at temperatures of 18°-24°C. The shell is re- tained in this species. 3. Metamorphosis in Elysia chlorotica occurred after a 16-day veliger stage in response to a primary film grown from sediments taken from the adult habitat. The percent of metamorphosed larvae was increased by using a 0.1% solution in seawater of succinylcho- line chloride in a plate with a primary film. The shell and operculum are discarded in this species. 4. Because they tolerate wide variation in physical envi- ronmental factors and have a relatively short plank- tonic stage, these estuarine opisthobranchs are good candidates for prolonged cultivation in the labora- tory. These two species are being maintained under defined environmental conditions throughout the en- tire life cycle in order to investigate the development of behavior in connection with the development of the nervous system. Page 304 THE VELIGER Vol. 21; No. 2 ACKNOWLEDGMENTS We would like to thank Helen Stanley of the Woods Hole Oceanographic Institution for providing the algal cultures, Dr. Jim de Boer for identifying the macro-algae, Ann Cor- nell for assistance in collecting, and Ruthanne Theran for technical assistance. Our thanks also to Drs. Carl Berg and Ruth Turner for their helpful comments and suggestions on the manuscript. Literature Cited ALDER, JosHUA & ALBANY Hancock 1854. Notice of some new species of British Nudibranchiata. Ann. Mag. Nat. Hist. (2) 14: 102-105 Akon, Danie- L. 1974a. Sensory interactions in the nudibranch mollusc Hermissenda crassicornis. Federation Proc. 33 (4): 1083-1090; 15 text figs. 1974b. Associative training of Hermissenda. Journ. Gen. Physiol. 64: 70-84; 11 text figs. 1975. Neural correlates of associative training in Hermtssenda. Baitey, KaniAutono H. «& J. S. BLEAKNEY 1967. First Canadian report of the sacoglossan Elysia chlorotica Gould. The Veliger 9 (3): 353 - 354 (1 January 1967) Berou, Rupo.r Lupwic SorpHus 1894. Die Opisthobranchiata. 25 (10): 125-235; plts. 1-12 1905. Die Opisthobranchiata der Siboga Expedition. peditie. Leiden 50 (1): 1-248; plts. 1-20 Bonar, Date B. 1976. Molluscan metamorphosis: A study in tissue transformation. Amer. Zool. 16 (3): 573-591 Bonar, Dave B. & Micuaer G. HaprFirip 1974. Metamorphosis of the marine gastropod Phestilla sibogae Bergh (Nudibranchia: Aeolidacea). I. Light and electron microscope analysis of larval and metamorphic stages. Journ. Exp. Mar. Biol. Ecol. 16 (3): 27-255; 18 text figs. Crark, Kerry B. 1975. Nudibranch life cycles in the Northern Atlantic and their rela- tionship to the ecology of fouling communities. Helgol. wiss. Mee- resunters. 27 (1): 28-69; 14 text figs. Bull. Mus. Comp. Zool. Harvard Siboga Ex- Cocks, W. P 1852. New species of Mollusca. Naturalist 2: 1; 3 text figs. Cooper, JAMES GRAHAM 1863. On new or rare Mollusca inhabiting the coast of California. Proc. Calif. Acad. Nat. Sci. 3: 56 - 60 Cuvigr, Grorce S. 1803. Mémoire sur le genre Tritonia, avec la description et l’anatomie d’une espéce nouvelle, Tritonia hombergii. Ann. Mus. Nation. Hist. Natur. Paris I: 480 - 496; plts. 31, 32 Davis, CHarRLes C. 1968. Mechanisms of hatching in aquatic invertebrate eggs. Oceanogr. Mar. Biol. Ann. Rev. 6: 325-376; 19 text figs. Davis, Witu1AM J. & Georce J. Mpitsos 1971. Behavioral choice and habituation in the marine mollusk Pleu- robranchaea californica MacFarland (Gastropoda, Opisthobranchia). Zeitschr. vergleich. Physiol. 75: 207 - 232; 22 text figs. Davis, Witi1am J., Georce J. Mritsos, Mexopy V. S. Siecier, J. Mi- CHAEL PINNEO & KaTHRYN B. Davis 1974. Neural substrates of behavioral hierarchies and associative learn- ing in Pleurobranchaea. Amer. Zool. 14 (3): 1037-1050; 11 text figs. Dorsett, D. A., ARTHUR O. D. Wittows & Grauam Hoye 1973. The neuronal basis of behavior in Tritonia. IV. The central origin of a fixed action pattern demonstrated in the isolated brain. Journ. Neurobiol. 4 (3): 287-300; 11 text figs. EscHSCHOLTz, JOHANN F. 1831. Zoologischer Atlas, prt. 4: 1-19; plt. 19 Franz, Davin R. 1970. Zoogeography of Northwest Atlantic opisthobranch molluscs. Mar. Biol. 7 (2): 171-180; 5 text figs. Goutp, Aucustus AppIson & WiLi1AM Greene BINNEY 1870. Report on the Invertebrata of Massachusetts. 2d ed, comprising the Mollusca. Boston: Wright & Potter, State Printers. pp. 1-524; 25 plts. GREENE, RicHARD W. 1968. The egg masses and veligers of southern California sacoglossan opisthobranchs. The Veliger 11 (2): 100-104; 6 text figs. (1 October 1968) 1970. Symbiosis in sacoglossan opisthobranchs: symbiosis with algal chloroplasts. Malacologia 10 (2): 357-368; 7 text figs. (10 July 1971) Guittarp, Rosert R. L. 1975- Culture of phytoplankton for feeding marine invertebrates. in: W. L. Smith & M. H. Chanley (eds.) Culture of marine inverte- brate animals, pp. 29-60. Plenum Press, New York Harris, Larry GARLAND 1973. Nudibranch associations. in: T. C. Cheng (ed.) Current topics in comparative pathobiology, vol. 2: 213 - 315. Acad. Press, London & New York Hoye, GraHAmM & ARTHUR O. D. WiLLows 1973. The neuronal basis of behavior in Tritonia. II. Relationship of muscular contraction to nerve impulse pattern. Journ. Neurobiol. 4 (3): 239-254; 7 text figs. Hurst, ANNE 1967. The egg masses and veligers of thirty northeast Pacific opistho- branchs. The Veliger 9 (3): 255 - 288; plts. 26-38; 31 text figs. (1 January 1967) JoHNson, CHartes W. 1934. List of marine Mollusca of the Atlantic coast from Labrador to Texas. Proc. Boston Soc. Nat. Hist. 40 (1): 1-204 Kanpet, Eric R. 1976. Cellular basis of behavior. cisco, California; 727 pp.; illust. KriecsTEeIn, ARNOLD R., Vincent CasTetLucci & Eric R. KANDEL 1974. Metamorphosis of Aplysia californica in laboratory culture. Proc. Nat. Acad. Sci. 71 (9): 3654 - 3658; 3 text figs. LinNAEus, CaroLus 1767. Systema Naturae, ed. 12, 1 (2): 1083 MacFarLanp, 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) W. H. Freeman & Co. San Fran- Marcus, Ernst 1961. Opisthobranch mollusks from California. (Supplement, part 1): 1-85; plts. 1-10 Montacu, GEorcE 1804. Description of several marine animals found on the South Coast of Devonshire. Trans. Linn. Soc. London 7: 61-85; plts. 6, 7 PFITZENMEYER, Hayes T. 1960. Notes of the nudibranch, Elysta chlorotica Gould, from Chesa- peake Bay, Maryland. Chesap. Sci. 1( 2): 114-115; 1 text fig. Russe_.t, Henry DruMMOND 1946. Ecologic notes concerning Elysia chlorotica, Gould and Stiliger fuscata, Gould. The Nautilus 59 (3): 95-97 (9 February 1946) 1964. New England nudibranch notes. The Nautilus 78 (2): 37-42 Say, THOMAS 1822. An account of the marine shells of the United States. Journ. Acad. Nat. Sci. Philadelphia (1) 2: 221 - 248 SMALLWoop, W. M. 1904a. The maturation, fertilization, and early cleavage of Haminea solitaria (Say). Bull. Mus. Comp. Zool. Harvard 45 (4): 261 to 318; 13 plts. 1904b. Natural history of Hamtnea solitarta (Say). 38 (447): 207-225; 16 text figs. StrentH, Nep E. & James E. BLANKENSHIP 1978. Laboratory culture, metamorphosis and development of Aplysia brasiliana Rang, 1828 (Gastropoda : Opisthobranchia). The Veliger 21 (1): 99-103; 1 text fig. (1 July 1978) Tarpy, JEAN 1970. Contribution 4 l’étude des métamorphoses chez les nudibranches. Ann. Sci. Nat.: Zool. et Biol. (12) 12: 299-370; 21 text figs. TuHompson, THomas EvERETT 1958. The natural history, embryology, larval biology and post-larval development of Adalaria proxima (Alder «& Hancock) (Gastropoda The Veliger 3 (1 February 1961) Amer. Nat. Opisthobranchia). Phil. Trans Roy. Soc. London, Ser. B 242: 1-58; 49 text figs. 1961. The importance of the larval shell in the classification of the Sacoglossa and the Acoela (Gastropoda, Opisthobranchia). Proc. Malacol. Soc. London 34 (4): 233 - 238 Vol. 21; No. 2 THompPpson, THomMAS EVERETT 1962. Studies on the ontogeny of Tritonia hombergii Cuvier (Gastro- poda: Opisthobranchia). Phil. Trans. Roy. Soc. London, Ser. B 245: 171-218; 30 text figs. 1967. Direct development in a nudibranch, Cadlina laevis, with a dis- cussion of developmental processes in Opisthobranchia. Journ. Mar. Biol. Assoc. U. K. 47 (1): 1-22; 8 text figs. THorson, GUNNAR 1946. Reproduction and larval development of Danish marine bottom invertebrates with special reference to the planktonic larvae in the sound (@resund). Medd. Komm. Danm. Fish, Havund (Plankton) 4 (1): 1-523; 199 text figs. Wittows, ArTHuR O. D. 1973. Learning in gastropod molluscs. in: Invertebrate learning, vol. 2. Arthropods and gastropod molluscs. W. C. Corning, J. A. Dyal « A. O. D. Willows (eds.). Plenum Press, New York, pp. 187-273, 27 text figs. Wittows, ArtHurR O. D., D. A. Dorsetr & GRAHAM HoyLe 1973a. The neuronal basis of behavior in Tritonia. I. Functional or- ganization of the central nervous system. Journ. Neurobiol. 4 (3): 207 -237; 9 text figs. 19736. The neuronal basis of behavior in Tritonia. III. Neuronal mech- anism of a fixed action pattern. Journ. Neurobiol. 4 (3): 255 - 285; 16 text figs. NOTE ADDED IN PROOF After the above paper had been accepted for publication, the following relevant publications on opisthobranch cul- ture appeared: Harrican, June F & Danier L. ALKoN 1978. Larval rearing, metamorphosis, growth and reproduction of the eolid nudibranch Hermissenda crassicornis (Eschscholtz, 1831) (Gast- ropoda : Opisthobranchia). Biol. Bull. 154 (3): 430-439; 3 text figs. Kempr, STEPHEN C. & A. O. Dennis WILLOWS 1977. Laboratory culture of the nudibranch Tritonia diomedea Bergh (Tritoniidae : Opisthobranchia) and some aspects of its behavioral development. Journ. Exp. Mar. Biol. Ecol. 30 (3): 261-276; 4 text figs. Switzer-DuNLAP, MarILyn & MicHAEL G. HapFIELD 1977. Observations on development, larval growth and metamorphosis of four species of Aplysiidae (Gastropoda, Opisthobranchia) in labora- tory culture. Journ. Exp. Biol. Ecol. 29 (4): 245-261; 4 text figs. NOTES & NEWS Additional Notes on Spurilla alba (Risbec, 1928) (Mollusca : Opisthobranchia ) BY, GALE G. SPHON Los Angeles County Museum of Natural History Los Angeles, California DuRING THE PAST SEVERAL YEARS, Forrest and Roy Poorman have collected opisthobranchs for the Los An- geles County Museum of Natural History, and have care- THE VELIGER Page 305 fully documented the specimens with 35mm color slides. Among the many lots donated to the Museum were 3 specimens of Spurilla alba (Risbec, 1928) collected in November, 1975. In 1971 this species had been reported from Punta Mita, Nayarit, Mexico, the first record for the Eastern Pacific (SpHoN, 1971). Aside from the type locality of Noumea, New Caledonia, it had also been re- ported from New South Wales and Queensland, Austra- lia (BuRN, 1966) and from Tanzania, Africa (EDMUNDS, 1969). Thanks to the efforts of the Poormans, I am now able to report this species from San Carlos Bay, near Guaymas, Sonora, Mexico, a range extension of about 800 km northward in the Eastern Pacific. Photographs taken of the Nayarit and one of the Sonor- an specimens (the other 2 were not photographed and had lost their color in the ethanol they were preserved in) show some variation in coloration. The Nayarit specimen is chalk-white with more intense white speckles covering the cerata and body. The Sonoran specimen has the same basic chalk-white but the speckles are brownish in color and give the animal a pinkish cast. At the base of the rhinophores in the Nayarit specimen is a vermillion-col- ored ring encircling them like a figure 8. The Sonoran specimen also has this, but there is an orange color that suffuses the lower 3 of the rhinophores. A lighter version of this orange coloration appears between the head ten- tacles on the Nayarit specimen, but is absent in the Sonoran one. In the original description, Risbec states that the ani- mal is able to swim by manipulating the cerata and rhi- nophores. This was mentioned by FARMER (1970) in his paper on swimming gastropods. However, it is doubtful that he has actually seen it swim and he is merely quoting what was stated by Risbec. Literature Cited Burn, Rosert 1966. Some opisthobranchs from southern Queensland. Journ. Malac. Soc. Austral. 1 (9): 96-109 EDMUNDS, MALCOLM 1969. Opisthobranchiate Mollusca from Tanzania. 1. Eolidaceae (Eu- branchidae and Aeolidiidae). Proc. Malacol. Soc. London 59 (5): 451 - 469 FARMER, WESLEY MERRILL 1970. Swimming gastropods (Opisthobranchia and Prosobranchia). The Veliger 13 (1): 73-89; 20 text figs. (1 July 1970) RisBEc, JEAN 1928. Contributions a l’étude des nudibranches Néo-Calédoniens. Faune Colon. Frang. 2 (1): 1-238; plts. 1-16 SpHon, Gate G. 1971. New opisthobranch records for the eastern Pacific. The Ve- liger 13 (4): 368-369 (1 April 1971) Page 306 Cypraea goodallu Sowerby, 1832 on Fanning Island BY HUGH BRADNER Scripps Institution of Oceanography La Jolla, California SEVERAL Cypraea goodallii Sowerby, 1832 were collected and studied on Fanning Island during the summer and winter of 1977. Fanning, a small atoll, is one of the Line Islands about 1 600 km due S of Hawaii and is one of the most easterly of the Pacific equatorial islands. There is only one deep-water pass into the lagoon. Cypraea goodalli were collected throughout daylight hours at a rate of about one per hour in depths of 0.15 to 1.5m under flat slabs of dead coral in calm water at the edge of the deep-water pass into the lagoon. The animals did not cling tightly and often fell off when the slab was turned. They were not associated with any particular sponge species. Body and foot are cream colored. Foot is small. Mantle is almost transparent, with sparse 2- and 3-branched short white papillae. Siphon is short, white, with a ring of about 12 short stubble-papillae around the tip and along the underside. Antennae are orange-yellow, straight, gent- ly tapered. Eyes are dark brown, small. One specimen was seen on a clump of about 100 eggs which have a color similar to that of the antennae. Nematodes in the Alimentary Canal of Terrestrial Slugs BY DARIO T: CAPPUCCTI, Jr. 1077 Sanchez Street, San Francisco, California 94114 RELATIONS BETWEEN nematodes and mollusks have been reviewed by Cuitwoop « Cuitwoop (1937), MALEK & CHENG (1974), MENGERT (1953), PELSENEER (1928), STEPHENSON & KNUTSON (1966), and others. Based on known differences in life cycle patterns, nematodes may occur in snails and slugs (Currwoop « Cuitwoop, op. cit.; MALEK & CHENG, op. cit.) as follows: 1) normally free-living and plant parasitic nematodes that may pass through the host’s digestive tract uninjured; 2) oblig- atory parasitic nematodes living in the host’s digestive THE VELIGER Vol. 21; No. 2 tract; 3) nematodes with parasitic larvae occurring in the foot muscles of the host and with a free-living adult stage; 4) adult nematodes living in the genital organs of the host; 5) agamic nematodes that live in the body spaces of the host and that leave the host upon reaching maturity to lead a free-living existence; and 6) para- sitic nematodes of vertebrates, the larvae of which occur in snails and slugs. As noted by MaLeK & CHENG (op. cit.), some nematodes cannot be fitted into any of the above categories at this time because of lack of informa- tion about their life cycles. According to OcREN (1959a, 1959b), nematodes are only occasionally encountered in gastropods, and hence the present writer decided to present his findings. During the years January 1973 through January 1978, a total of 657 snails [Helix aspersa Miller, 1774] and 645 slugs [439 Deroceras laeve (Miller, 1774), 200 D. reticulatum (Miller, 1774), 5 Limax maximus Linnaeus, 1758, and 1 Arion circumscriptus Johnston, 1828] were collected from the same location, a semi-rural tract approximately 1.2 hectares in size, situated at the junction of the city limits between Martinez and Pleasant Hill in Contra Costa County, California. Nematodes were obtained from only 4 slugs (all D. laeve, collected 10 May 1975) out of the total of 1 302 gastropods examined. Three slugs yield- ed one nematode each in the alimentary canal. From the intestinal tract of the 4" slug, 3 nematodes were recover- ed. The nematodes, all females, were morphologically the same. A positive identification was not made, however, due to the lack of male specimens. Further material is needed. The 6 specimens have been deposited with the Diagnostic Service, Department of Entomological Scien- ces, University of California, Berkeley. This report illustrates a basic problem of obtaining ample and appropriate specimens of roundworms from gastropods in order to make a satisfactory identification of the parasite or pseudoparasite. The problem is one that concerns both the malacologist and the parasitologist (TurRNER & Pini, 1960). Too often, hundreds or even thousands of mollusks may be examined in vain by the parasitologist, while the unsuspecting malacologist may innocently discard parasitized animals, and with them the nematodes. The cooperation between the malacologist and the parasitologist is encouraged for the more effi- cient elucidation of both natural and experimental mollusk-nematode relationships. ACKNOWLEDGMENTS Thanks are extended to the late Mr. Allyn G. Smith, Mr. Barry Roth, Mr. Robert E. Jones, Dr. George M. Davis, Dr. George O. Poinar, Jr. and Dr. Ruth D. Tumer. Vol. 21; No. 2 THE VELIGER Page 307 Literature Cited Cuitwoop, Benjamin G. & May Bette H. Cuttwoop 1937. Snails as hosts and carriers of nematodes and nematomorpha. The Nautilus 50 (4): 130-135 (4 May 1937) MALek, Emire A. & THomas C. CHENG 1974. Medical and economic malacology. Acad. Press, Inc., New York & London MEnNGERT, HERTA 1953. Nematoden und Schnecken. 41 (4): 311-349 OcreN, Rosert E. 1959a. The nematode Cosmocercoides dukae as a parasite of the slug. Proc. Penn. Acad. Sci. 33: 236 - 241 1959b. The nematode Cosmocercoides dukae as a parasite of the slug. Journ. Parasitol. 45, suppl.: 45 PELSENEER, PAUL 1929. Les parasites des mollusques et les mollusques parasites. Bull. Soc. Zool. France 53: 158 - 189 STEPHENSON, JEFFREY W. & Lioyp V. KnuTsoNn 1966. A résumé of recent studies of invertebrates associated with slugs. Journ. Econ. Entomol. 59 (2): 356 - 360 Turner, Rutu Dixon & MabDELINE A. Pini 1960. The occurrence of a nematode parasite in the genus Stylodon. Journ, Malacol. Soc. Austral. (1) 4: 56-59 x+ 398 pp.; illust. Zeitschr. Morph. Okol. Tiere INTERNATIONAL CONFERENCE ON THE HISTORY or Museums AND CoLLEcTIONS IN NATURAL History (April 1979) The Society for the Bibliography of Natural History, to- gether with the specialist professional Biology Curators Group and the Geological Curators Group, are sponsoring this Conference, to be held at the British Museum (Nat- ural History), London on the 4" to 6" April, 1979. The increasing importance of and interest in Museums and their holdings in the Natural Sciences and the present growth of studies into their history, indicated that the sub- ject required an International Forum. The aim of this Conference is to bring together specialists in the various disciplines from throughout the world, historians of sci- ence, curators, librarians and bibliographers. To achieve this, papers are invited upon a very wide range of subjects, which will be presented in the 4 sessions of the meeting. The range of topics includes: the history of individual public and private museums; studies of muse- ums within a particular geographical area, time-span, or scientific discipline; the lives and activities of collectors of fossils, minerals, plants, or animals; studies of natural history libraries and book-collectors; the history of zoos and botanical gardens; the sale and dispersal of notable libraries and natural history collections; the documenta- tion of museums and private collections; the relationship of bibliography to collecting; and the growth of museums and studies on collections resulting from expeditions and exploration. All papers submitted, whether read or not, will be considered for publication in a special volume. In addition to the sessions of papers, exhibitions of natural history collections, books and manuscripts will be prepared in London museums and libraries. It is also intended to visit other institutions in the Home Counties on the 6" April. For further information, please contact: Mrs. J. A. Diment (Organising Secretary), Palae- ontology Library, British Museum (Natural Histo- ry), Cromwell Road, London SW7 5BD, United Kingdom. W. 5S. M. THE 1979 MEeTING of the Western Society of Malaco- logists will be held jointly with the American Malacologi- cal Union in Corpus Christi, Texas, August 5 through August 11. Meetings will convene at La Quinta Royale, a beautiful new motor inn one block from the shoreline. Field trips, workshops, and symposia on Gulf of Mexico mollusks and Life-Histories of Mollusca are scheduled. A call for contributed papers, on these and any other ma- lacological topics will be issued early in 1979. Informa- tion about the meeting is available from Mr. Barry Roth, President, W. S. M., Department of Geology, California Academy of Sciences, San Francisco, CA 94118. At the 11" Annual Meeting of the Western Society of Malacologists, June 30, 1978, the following slate of officers was elected to serve during the fiscal year 1978/79: President: Barry Roth First Vice-President : Dr. Vida C. Kenk Second Vice-President: Carol C. Skoglund Secretary: William D. Pitt Treasurer: Carol C. Skoglund Members-at-Large: Michael G. Kellogg David R. Lindberg Applications for membership should be sent to Mrs. Carol C. Skoglund, Treasurer, 3846 E. Highland Ave., Phoenix, AZ 85018. Dues: regular membership — $7.50; additional family members — $1.00 per person; student membership — $3.00. Regular and student members re- ceive the Annual Report, containing the published proceedings of the Annual Meeting. Back issues of many Annual Reports, and W.S. M. Oc- casional Paper No.2, “A Catalogue of Collations of Works of Malacological Importance” by George E. Radwin and Eugene V. Coan, are available. Address requests to Mrs. Carol C. Skoglund, Treasurer, 3846 E. Highland Avenue, Phoenix, AZ 85018. Page 308 Sale of C. M. S. Publications: Effective January 1, 1978, all back volumes still in print, both paper-covered and cloth-bound, will be available only from Mr. Arthur C. West, P.O. Box 730, Oakhurst, CA (lifornia) 93644, at the prices indicated in our Notes and News section, plus postage and, where applicable, California State Sales Tax. The same will apply to the Supplements that are still in print, except for supplements to vol. 7 (Glossary) and 13 (Ovulidae), which are sold by The Shell Cabinet, P O. Box 29, Falls Church, VI (rginia) 22046; and supplement to volume 18 (Chitons) which is available from Hopkins Marine Station, Pacific Grove, CA (lifornia) 93950. Volumes 1 through 8 and 10 through 12 are out of print. Volume 9: $22.- — Volume 13: $24.- — Volume 14: $28.- Volume 15: $28.- Volume 16: $32.- Volumes 17 to 20: $34.- each. Postage and handling extra. There is a limited number of volumes 9, 11, 13, 14 to 20 available bound in full library buckram, black with gold title. These volumes sell as follows: 9 - $27.-; 11 and 13 - $29.- each; 14 and 15 - $33.- each; 16 - $38.-; 17, 18 and 19 - $41.75 each; 20 - $42.25. Supplements Supplement to Volume 3: $6.- [Part 1: Opisthobranch Mollusks of California by Prof. Ernst Marcus; Part 2: The Anaspidea of California by Prof. R. Beeman, and The Thecosomata and Gymnosomata of the Cali- fornia Current by Prof. John A. McGowan] [The two parts are available separately at $3.- each] Supplement to Volume 6: out of print. Supplement to Volume 7: available again; see announce- ment elsewhere in this issue. Supplement to Volume 11: $6.-. [The Biology of Acmaea by Prof. D. P. Assorrt et al., ed.} Supplement to Volume 14: $6.-. [The Northwest American Tellinidae by Dr. E. V. Coan] Supplement to Volume 16: $8.-. [The Panamic-Galapagan Epitoniidae by Mrs. Helen DuShane] Orders for any of the publications listed above should be sent directly to Mr. Art West. If orders are sent to us, we will forward them. This will necessarily result in delays. THE VELIGER Vol. 21; No. 2 A Glossary of A Thousand-and-One Terms Used in Conchology by WiniFrReD H. ARNOLD originally published as a supplement to volume 7 of the Veliger has been reprinted and is now available from The Shell Cabinet, Post Office Box 29, Falls Church, Virginia 22046, U. S. A. The cost is US$ 3.50 postpaid if remittance is sent with the order. Supplement to Volume 15: Our stock is exhausted, but copies are still available from The Shell Cabinet, P. O. Box 29, Falls Church, Virginia 22046. [A systematic Revision of the Recent Cypraeid Family Ovulidae by Crawrorp NEILL CATE] Other supplements: [Growth Rates, Depth Preference and Ecological Succes- sion of Some Sessile Marine Invertebrates in Monterey Harbor by Dr. E. C. Haderlie] Supplement to Volume 17: Our stock of this supplement is exhausted. Copies may be obtained by applying to Dr. E. C. Haderlie, U. S. Naval Post-Graduate School, Mon- terey, CA (lifornia) 93940. Supplement to volume 18: $9.50 postage paid. [The Biology of Chitons by Robin Burnett e¢ al.]. (Our supply of this supplement is exhausted; however, copies may be available by making application to the Secretary, Hopkins Marine Station, Pacific Grove, Cali- fornia 93950.) WE ARE PLEASED to announce that an agreement has been entered into by the California Malacozoological Society, Inc. with Mr. Steven J. Long for the production and sale of microfiche reproductions of all out-of-print editions of the publications of the Society. The microfiches are available as negative films (printed matter ap- pearing white on black background), 105mm & 148mm and can be supplied immediately. The following is a list of items now ready: Volume 1: $1.50 Volume 6: $4.50 Volume 2: $3.00 Volume 7: $6.00 Volume 3: $3.00 Volume 8: $6.00 Volume 4: $4.50 Volume 10: $9.00 Volume 5: $4.50 Volume 11: $9.00 Volume 12: $9.00 Supplement to Volume 6: $1.50; to Volume 18: $3.00 Vol. 21; No. 2 California residents please add the appropriate amount for sales tax to the prices indicated. Please, send your order, with check payable to Opistho- branch Newsletter, to Mr. Steven J. Long, P. O. Box 243, Santa Maria, CA 93454. Volumes and Supplements not listed as available in microfiche form are still available in original edition from Mr. Arthur C. West, P O. Box 730, Oakhurst, CA(lifornia) 93644. Orders should be sent directly to Mr. West. Single Copies of “The Veliger”’: We have on hand some individual copies of earlier issues of our journal and are preparing a list of the various issues available with the prices. Some issues are present in only one or two copies, while others may be present in 10 or more copies. As we are anxious to make room, we will offer these numbers at an exceptionally low price. This list will be presented in a forthcoming issue in the Notes and News section. These individual issues will be available only directly from the Society. Details on how to order such copies will be given when the list is published. Subscription rate to Volume 21 is $30.- plus postage. Pp 30.- plus postag We must emphasize that under no condition can we ac- cept subscription orders or membership applications for calendar year periods. If “‘split volumes” are required, we must charge the individual number costs. Individual issues sell at prices ranging from US$12.00 to US$30.00, depending on the cost to us. Backnumbers of the current volume will be mailed to new subscribers, as well as to those who renew late, on the first postal working day of the month following receipt of the remittance. The same policy applies to new members. THE VELIGER is not available on exchange from the Cali- fornia Malacozoological Society, Inc. Requests for re- prints should be addressed directly to the authors con- cemed. We do not maintain stocks of reprints and also cannot undertake to forward requests for reprints to the author(s) concerned. WE CALL THE ATTENTION or our foreign correspondents to the fact that bank drafts or checks on banks other than American banks are subject THE VELIGER Page 309 to a collection charge and that such remittances cannot be accepted as payment in full, unless sufficient overage is provided. Depending on the American banks on which drafts are made, such charges vary from a flat fee of $1.- to a percentage of the value of the draft, going as high as 33%. 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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. 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Page 310 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. Requests to be placed on this special mailing list should be sent to Dr. George V. Shkurkin, Manager, 1332 Spruce Street, California 94709 However, until further notice, we are suspending the pub- lication of supplements until it will be reasonably certain that we will not be forced to spend many hours in tracing of lost insured or registered parcels and entering claims for indemnification. The special mailing list of members and subscribers who have entered an “including all sup- plements” will be preserved because of our innate opti- mism that sometime within our lifetime the postal services throughout the world will return to the former excellent and reliable performance. Moving? If your address is changed it will be important to notify us of the new address at least six weeks before the effective date, and not less than six weeks before our regular mailing dates. Because of a number of drastic changes in the regulations affecting second class mailing, there is now a sizeable charge to us on the returned copies as well as for our remailing to the new address. 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. Effective January 8, 1968 the following charges must be made: THE VELIGER Vol. 21; No. 2 change of address - $1.- change of address and re-mailing of a returned issue $2.75 minimum, but not more than actual cost to us. 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. At present we are charged a minimum fee of $12.50 on each order for new addressograph plates. For this rea- son we hold off on our order until 6 weeks before mailing time, the very last moment possible. If, for any reason, a member or subscriber is unable to notify us in time and also is unable to make the proper arrangement with the Post Office for forwarding our journal, we will accept a notice of change of address, accompanied by the proper fee and a typed new address on a gummed label as late as 10 days before mailing time. We regret that we are absolutely unable to accept orders for changes of address on any other basis. In view of the probable further cur- tailment in the services provided by the Postal Service, we expect that before long we may have to increase these time intervals. The regulations pertaining to second class mailing re- quire “pre-sorting” of the mail which involves a large amount of time, especially if the total number of pieces is too small to warrant the employment of computeriza- tion. This requirement seems justified as long as the rates for second class matter remain substantially below those for first class matter. 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Also, if a copy is returned we will, as in the past, advise the member of this fact and indicate the total costs incurred for which we must seek reimbursement. If this reimbursement is not made, we cannot continue to send future issues to the delinquent member. Membership will have to be Vol. 21; No. 2 considered as terminated and can be re-instated only upon payment of all arrears. We regret that this apparently hard rule is necessary, but we wish to continue publishing the Veliger — which will not be possible if these rules are not observed. Regarding UNESCO Coupons We are unable to accept UNESCO coupons in payment, except at a charge of $4.25 (to reimburse us for the ex- penses involved in redeeming them) and at $0.95 per $1.- 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. 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 ‘Ireasurer of the C. M. S., Inc. will issue suitable receipts which may be used by Donors to substan- tiate their respective tax deductions. Membership open to individuals only - no institutional or society memberships. Please send for membership ap- plication forms to the Manager or the Editor. Membership renewals are due on or before April 15 each year. If renewal payments are made after April 15 THE VELIGER Page 311 but before March 15 of the following year, there will be a re-instatement fee of $1.-. Members whose dues pay- ments (including the re-instatement fee) have not been received by the latter date, will be dropped from the rolls of the Society. They may rejoin by paying a new initiation fee. The volume(s) published during the time a member was in arrears may be purchased, if still available, at the regular full volume price plus applicable handling charges. Endowment Fund In the face of continuous rises in the costs of printing and labor, the income from the Endowment Fund would materially aid in avoiding the need for repeated upward adjustments of the membership dues of the Society. It is the stated aim of the Society to disseminate new infor- mation in the field of malacology and conchology as widely as possible at the lowest cost possible. At a Regular Membership meeting of the Society in No- vember 1968 a policy was adopted which, it is hoped, will assist in building up the Endowment Fund of the Society. 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. REGARDING POSTAL SERVICE Complaints regarding late arrival of our journal are in- creasing in number, steadily, continually. However, we very conscientiously dispatch our journal on the printed publication dates. What happens after deposition at the Post Office is, of course, beyond our control. From some of our members we have been able to construct a sort of probable delivery schedule. In general, within California, 8 days is usual; outside of California, the time lapse in- creases with the distance; the East Coast can consider a lapse of “only” two weeks as rapid service; 4 to 5 weeks are not uncommon. Foreign countries may count on a minimum of one month, six weeks being the more usual time requirement and over two months not rare! In view of the ever increasing difficulties in the postal service, it is essential that members and subscribers not only give us prompt and early notice of address changes, but that proper arrangement for forwarding of our jour- nal be made with the local post office (at the old address). Ragergm2 The Latest New Postage Rates Effective on May 29, 1978, the U.S. Postal Service in- creased rates for first, third and fourth class matter, as announced some months before. However, although not announced publicly and without notification to publishers, second class postage rates within the United States were also increased. Further, again without advance notfica- tion, postage for second class matter to the so-called PU- AS countries (Spanish-speaking countries and Brasil), which had traditionally been lower than to all other for- eign countries, was increased to the same rate. On July 6 a further increase of postage rates within the United States went into effect. This increase came also as a surprise to us, since we had assumed that the May increase was taking the place of the so-called phased in- creases which are scheduled for the sixth of July each year. It is obvious that we are forced to pass these increases on to our members and subscribers. Therefore, effective immediately, we must charge US$3.50 for postage to all addresses outside the United States. What increases we may have to make in the U.S. A. remains to be seen. As on several previous occasions, we are again the losers in this case. Since our subscription renewals as well as membership dues were due prior to the 29th of May, no provision for the increases had been made; and it is too costly to send out bills for the additional $1.-. The “phased” increases are, of course, acceptable since these are known to the publishers; but these unannounced increases may quite easily lead to the demise of many periodical publications. Frankly, we are very pessimistic about the future fate of our publication, not only because of these erratic increases in postage rates, but also because of the continued lack of improvement in the postal service. As our members are aware, we have already been forced to suspend publication of our supplements. In this connection it seems desirable to once again stress the importance that changes of address (accom- THE VELIGER Vol. 21; No. 2 panied by the fee of US$ 1.00) be communicated to us AT LEAST SIX WEEKS before our regular mailing dates. We must make an ad- dress change even if only one digit in the ZIP code is changed; the cost to us is the same as for a completely new address. The Postal Service policy in regard to forwarding mail is generally not well known. First class matter will be forwarded up to one year if a request to that effect is filed. Second class matter will not be forwarded after go days, even if forwarding postage is guaranteed. Items that are not forwardable will be returned to the sender IF retumm postage is guaranteed. Since our copies frequently weigh in excess of one pound, return postage is very high. We have, in the past, had to pay as high as $1.80 for returned copies. It is more than likely that return postage henceforth will also be higher. It should not surprise any person to realize that we cannot re-mail a returned copy without re-imbursement for return postage, postage in- curred in correspondence with the addressee and the costs of re-packing and re-mailing. If prompt reimbursement is not made, we are forced to suspend service on the par- ticular subscription or membership. Under no circumstances are we able to supply free re- placement copies of issues that fail to reach their proper destination. However, we will ship by insured mail re- placement copies at half the announced single copy rate of the particular issue plus postage. We have developed a triple check system so that, if we say that a copy has been mailed, we are absolutely certain that we delivered that copy to the post office in Berkeley and on the date we indicate. From our experience with the loss of insured mail, we are tempted to suggest that subscribers figure on a 10% reserve fund for the purchase of replacement copies. The only alternative remaining would be for us to increase subscription rates and membership dues by at least 10%. This, however, does not seem quite fair to us as some of our subscribers in almost 20 years have never failed to receive their copies. THE VELIGER A Quarterly published by CALIFORNIA MALACOZOOLOGICAL SOCIETY, INC. Berkeley, California VOLUME 21 JANUARY I, 1979 NuMBER 3 CoNnTENTS A Comparative Study of the Structure, Development and Morphological Relation- ships of Chambered Cephalopod Shells. (6 Plates; 27 Text figures) ISVALS (BANDED & SIGURD)V,/DOLEIZEY. 12) 6) 04 2) ee ee a es oo 38 First Record of Okenia impexa Marcus, 1957 from the Western Atlantic in the Mediterranean. (1 Plate; 2 Text figures) SUIS HES CH MEK E Umer mer airs ©. w ian WAMird toe Sool isl al em) ue Mec), a ere BOG Malagarion paenelimax gen. nov., spec. nov., A New Slug-like Helicarionid from Madagascar (Pulmonata : Helicarionidae). (8 Text figures) SIMGNMUCUDIER Mme amas Eaten Beane olhiy Co chile) vane et air enh ve) vo BOE A Fossil Haliotss from the Galapagos Islands. (2 Plates) AERATOR ETA Merce cy ear ciuenneninrena) Wadi MMe Lett) al ons ete, a! fey, BOQ California’s Cretaceous Haliotts. (1 Plate) RV VAT TaD URE ARR Moneta Se aan en! Gel seve ee se 39S Chlamydoconcha orcutti Dall: Review and Distribution of a Little-Known Bivalve. ANE Sel CARU TONE rasmus tite MSE Sa wi i elife ll o) e eee ee QTD Description of a Previously Misidentified Species of Epitonium (Gastropoda : Epi- toniidae) . (2 Text figures) LIE TENG DUSHANE MM a arr) Memon ian ne) Ae 2a) Golfers ee) see 0 SYD Sexual Characteristics of Margaritifera margaritifera (Linnaeus) Populations in Central New England. (1 Text figure) DOUGEASG MOMULH MUON mine nen PUR eet cor aia aay ide a ts. oo GBI The Population Dynamics of Two Sympatric Species of Macoma (Mollusca : Bival- via). (17 Text figures) foun; GrssONpRAE Mena yee ete ee ee i ee te BBG [Continued on Inside Front Cover] er 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, Fasary, Subfamily, Genus, (Subgenus) New Taxa Second Class Postage Paid at Berkeley, California Contents — Continued Notes on the Winter Epiphragm of Pupoides albilabris. (1 Text figure) M,. CHRISTOPHER BARNHART . 4) 20) hc Vas) Re eat cen ee aye en A OG NOTES :& NEWS) 3) o'3 802k ay Or ARS cose Ot a Ans oe ane ee eA 2 A Range Extension of Anachis lillianae Whitney, 1978. R. A. WHITNEY BOOKS; PERIODICALS & PAMPEUILEIRS 2) 0 ume Wen an) es aya eam nner cns ae SS 4 Distributed free to Members of the California Malacozoological Society, Inc. Subscriptions (by Volume only) payable in advance to Calif: Malacozool. Soc., Inc. Volume 21: $30.- plus postage ($1.- in U.S. A.; $3.50 to all foreign Countries) Single copies this issue $22.00. Postage additional. Send subscription orders to California Malacozoological Society, Inc. 1584 Milvia Street, Berkeley, CA 94709, U.S.A. Address all other correspondence to Dr. R. STOHLER, Editor, Department of Zoology University of California, Berkeley, CA 94720 Vol. 21; No. 3 THE VELIGER Page 313 A Comparative Study of the Structure, Development and Morphological Relationships of Chambered Cephalopod Shells KLAUS BANDEL Department of Geology and Mineralogy, University of Jordan, Amman, Jordan AND SIGURD v. BOLETZKY Laboratoire Arago, L. A. 117 C.N.R. S. F66650 Banyuls-sur-Mer, France (6 Plates; 27 Text figures) INTRODUCTION AMoNG THE RECENT CEPHALOPODS, chambered shells are confined to the members of three families: the Nauti- lidae, with only a few species of Nautilus that represent the nearly extinct subclass Nautiloidea; in the Coleoidea (order Sepioidea) the monotypic Spirulidae and the spe- ciose Sepiidae, the common cuttlefishes. The shell of Nautilus is external, whereas the Spirula shell and the “cuttlebone” of the Sepiidae are internal, as are those of all coleoid cephalopods. The general as- pect of these three types of chambered shell is rather dif- ferent. The shells of Nautilus and Spirula show some re- semblance in that they are coiled and have large cham- bers, in contrast to the cuttlebone which is straight and has numerous extremely narrow chambers. However, the coiling of the external shell of Nautilus is exogastric, whereas the coiling of the internal Spzrula shell is endo- gastric. Despite its straight form, the cuttlebone presents signs of a close relationship with the coiled Spirula shell. These general aspects were known in the last century. If there has never been a doubt about the buoyancy function of the gas-filled chambered shell, its actual functioning has only recently been elucidated. With the use of scan- ning electron microscopes, it has become possible to ana- lyse in great detail the ultrastructure of these aragonitic shells, recent and fossil. This structural analysis provides a sound basis for the comparative study of the functional morphology of the chambered cephalopod shells, and more particularly of their siphuncular system, which is known to be responsible for buoyancy regulation. The present study follows this line of investigation. Along with the presentation of new data on the ultrastruc- ture of the Spirula shell and of the cuttlebone through- out its development, a comparative account of the struc- tural aspects of chambered shells in general is attempted, with the aim to unravel some of the complications arising from the different interpretations presented in the litera- ture. MATERIAL anp METHODS Specimens of Sepia were collected at Banyuls-sur-Mer, (Western Mediterranean), Port Sudan and Suakin (Red Sea) ; Spirula shells on the Canary Islands (Eastern At- lantic) and at Santa Marta (Caribbean). Shell material was prepared for observation in the Scanning Electron Microscope (“Cambridge Instru- ments”) by oriented breaking, washing with distilled water (no etching!), mounting on metal supports and coating with carbon and gold. Embryonic shells were removed mechanically and washed in water. For histological investigations, speci- mens were either fixed in Bouin’s fixative, embedded in paraffin, sectioned at a thickness of 7 4m and stained with Azan or Masson’s Trichrome; or pieces of fresh material were fixed in 1% OsO, in sea water for 1 to 2 hours, Page 314 embedded in Epon, and sections ranging from about 0.5 to 1.5 jm were cut with glass knives on an ultramicro- tome. These sections were stained with a mixture of Methylene blue and Azur blue. CHAMBERED SHELLS 1n SEPIOIDEA Morphology and Structure of the Shell in Sepza The shell of Sepia has been described in detail by APPEL- LOF (1893). This author also discussed older literature dating back to the 18 century. The terminology we use for the different parts of the cuttlebone is largely adopted from Appelléf and translated from German (Figure 1). For some details, the terms used by DENTON & GILPIN- Brown (1961), are given preference to those of Appellof. The cuttlebone consists of a dorsal shield (“Rticken- schild”) and the ventral chamber zone (“Wulst”). The spine (““Dorn”, “Rostrum’’) is situated on the mid-dorsal line on the convex dorsal shield, close to its posterior end. The upper side of the dorsal shield is covered by calcare- ous tubercles; the posterior and the marginal portions are smooth. Appelléf called the part that surrounds the spine “Dornhiille,” i. e., cover of the spine. The ventral side of the dorsal shield bears the convex chamber complex, which thins out towards the posterior end. On the ventral surface of the chamber zone, we distinguish the siphuncular zone (“gestreifter Wulst’’) from the zone of the last-formed chamber (“ungestreifter Wulst”). The posterior portion of the chamber zone is embraced by the fork (“Gabel”). The fork is broad pos- teriorly and narrows anteriorly on each side; it ends near the siphuncular surface of the last-formed chamber (last “Wulststreifen”). A calcified rim (“‘verkalkte Randzone”), accompanied by an uncalcified outer rim (“unverkalkte Randzone”’) of the dorsal shield, surrounds the fork and the chamber zone. The dorsal shield consists of three layers (Figure 2). These are the uppermost, dorsal layer (‘“‘Riickenplatte”), the central layer (“‘Mittelplatte”) and the inner layer (“Innenplatte”). The central layer emerges at the rim of the dorsal shield; it is characterized by organic and miner- alized lamellae. The inner layer begins somewhat inward of the mainly organic rim of the dorsal shield; it con- sists of two portions, an upper, coarsely columnar pris- matic layer (“‘Pfeiler-”, i.e., pillar-like crystals) next to the central layer, and a lower, spherulitic prismatic layer (“besenartige,” 7. e., broom-like crystals). The dor- sal layer covers the upper intra-marginal portion of the dorsal shield. Appellof differentiates between two portions, the middle and anterior undulating, nodular layer (“Hok- kerpartie”) and the posterior area of the spine cover (cf. THE VELIGER Vol. 21; No. 3 SZ Figure 1 A: Ventral view of a Sepia shell with the siphuncular zone (sz) and the last chamber (Ic) surrounded by a calcified rim (cr) and an outer uncalcified rim (ur). The so-called fork (f) is restricted to the posterior part of the shell around the siphuncular zone. The spine (s), which projects from the dorsal side, is only partly seen at the posterior end of the shell. B: The position of the cuttle-bone in the dorsal part of the mantle is shown in a swimming animal (cf. also Figures 10, 11, 15, 17, 98 and 99) Vol. 21; No. 3 THE VELIGER \\ , ff Sm ? Yay MW) sy NWO ZINES LAAZA cl \ ; 1 TMA \ i) 1 h- { Be \ \ \ ‘ \ A | Y NANO ir 1 Wy VN ! Vat Vie AN WAS Nar NS ACAY \ i Ne \ ‘a K Yiass [Aga ul Vise a Nau \ Tease ' nAy* | ) ri A ANS is A aN UT UES oh lily je il | WO tat, au ip t y YU iv\4 i\s WEG Be id SNe’ Norma TA Thar AA, Wy, pNVIN No FON AMEN wh, NIRA aN aN i ve Wier = Ness) WA Wits ASS een aA \V4 dV AWN Lia WN = WAVING \i Page 315 iy \\ Figure 2 A cross section through the posterior part of the Sepia shell, showing the insertion of the chamber zone (cz) on the lower side of the dorsal shield (ds), the latter comprising 3 layers: the dorsal layer (dl), the central layer (cl), and the inner layer (il). Between the above). In our study, the spine and its surroundings are included in the central layer because of their structural similarity. The fork consists of several separate layers (“Gabelsepta”), each of which shows a finely laminated structure. The chambered part consists of cavities (“Hohlen- schichten”’), separated by septa. Each septum is made of a chamber roof (ventral portion of the septum) and a chamber floor (dorsal portion of the septum) (Figure 3). Within the chambers, vertical pillars and walls (“Pfei- ler”) form the supporting elements of the septa. In addi- tion to the septa, organic membranes are suspended be- tween the pillars (“freigespannte Membranen’”) (Fig- ure 2). After a chamber is completed by the formation of the (ventral) chamber floor, formation of a new chamber Starts with the chamber roof completing the last septum (cf Figure 3). The chamber roof consists of a prismatic layer composed of rectangular, rod-like prisms (0.4 um wide) (Figures 28, 82). The smallest components which marginal part of the inner layer and the chamber zone lies the fork (f). Within the chambers, organic membranes (om) are sus- pended between the pillars (p). cf vcr ventral Figure 3 Cross-section through a septum of the Sepia shell. The septum (s) comprises the chamber floor (cf ) with the base of the pillars (p) of the upper chamber and the chamber roof (cr) with the “tops” of the pillars (p’) of the lower chamber Page 316 make up these prisms are angular elements with a width of 0.2 um. At the insertion of the pillars and pillar walls, the prismatic crystal rods of the roof extend, without in- terruption, into the base of the forming pillar. The cham- ber roof is about 7 pm thick; it is continuous with the floor of the older (upper) chamber (cf. below) ; there are no separating structures such as organic layers. Where they emerge from the chamber roof, the pillars are either round, columnar, or they are straight or slightly undulating wall-like structures; these walls have about the same thickness as the columnar pillars. The prismatic structure of the chamber roof disappears in the basal part of the pillar; it grades into the lamellar structure with the appearance of the first annulation. The pillar annula- tions (38 to 62 in the central area of the chamber zone of Sepia orbignyana) are continuous in many pillars of one and the same area of a chamber, but they are not so in all pillars of a chamber. This can also be noted with the organic sheets that are extended between pillars. The central zone of one chamber may have 5 to g such sheets, extended parallel to thesepta (Figures 29, 30). These sheets are not seen as distinct organic layers within the pillars, but probably they are continuous. Within the pillars, the organic material is incorporated in the crystal fabric. The organic sheets are often found to split into a number of thinner sheets when they approach a pillar, so that only thin organic sheets are incorporated into adjacent por- tions of the calcareous fabric of the pillar. The “fusion” of these thin sheets at some distance from the pillars is prob- ably secondary; it may result from artifactual agglutina- tion of the wet membranes during drying of the cuttle- bone. The pillar annulations are 1 um to 8 wm wide. The crys- tals making up the pillar lamellae are quite irregular in shape; the most common form is a brick-like component (0.2 um wide) with its long axis usually following the axis of the pillar (Figures 78, 79, 82). Close to the chamber floor, the walls show stronger bending, and pillars tend to branch (Figures 30, 31, 80, 81). The surface of the pillars in the ventral part of the chamber is thus enlarged. Also wall-like pillars tend to divide into many branches, and columnar pillars show bi- lateral flattening in their different branches. Along with this crenelation and flattening, the undulating sheets thus “disintegrate”. The ventral side of each chamber is there- fore more permeable than the dorsal part, where the base of a pillar wall is generally continuous. The crystal growth of the ventral pillar branches that turn into the chamber floor is continuous, without any or- ganic or mineral layer between pillar and floor. KAELIN’s (1967) statement that the wall-like pillars are not solidly fused with the chamber floor is erroneous. THE VELIGER Vol. 21; No. 3 The chamber floor is about 15 4m thick; it shows a lamellar structure, with lamellae that are about 0.1 wm thick (Figures 28, 82). In its middle part, this floor layer is made of 0.2 4m wide, needle-shaped crystallites that show a common orientation within each layer. In their first-formed layers, the lamellar structure of the floor is composed of shorter rod-like elements, oriented parallel to the plane of lamellation. With its gradual transition into the roof of the next chamber, the lamellae show rod-like components with gradually changing orientation, from parallel to lamellation through vertical position, until lamellation is largely or entirely lost in the roof of the next chamber (Figure 28). Away from the central region of the chamber, pillars become shorter (Figures 75, 76); in the anterior region of the chamber, they are fused into wall-like ridges or simple ridge-like structures. Towards the posterior end, close to the siphuncular zone of each chamber, the con- trary is found. Here pillars become thinner and more columnar than in the central part of the chamber, and they are more closely set (Figure 31). The number of organic sheets expanded between pillars decreases towards the anterior margin, where the cham- ber height decreases. This decrease is less distinct in the lateral parts, where the chamber height decreases more abruptly (Figure 2). In the siphuncular zone, no calcareous floor is formed. The calcareous layers of the chamber floor are continuous with the organic sheets that cover the siphuncular area (Figure 37). In the siphuncular zone, the pillars are more numerous close to the posterior end of the chamber, where they are much shorter according to the lower chamber height. From the central area of the shell, organic sheets extend only in the foremost part of the siphuncular area. Here we find few sheets extended parallel to the roof; there are more sheets extended vertically betwen pillars (Figurs 32, 33). In the low posterior part of the siphuncular zone, be- tween the short, thin pillars, we find a dense growth of short, columnar crystals, plate-like crystals, and crystal aggregates (Figures 34, 35, 36). These crystals are large in comparison with those forming the pillars, and they show well-developed crystallographic planes and faces (Fig- ures 35, 36). Near the posterior end of the chamber, the growth of crystals is so dense that they form a closure between the organic floor and the calcareous roof. Further anteriorly, the crystal growth forms a porous layer together with the rearmost short pillars. More anteriorly again, at about half of the length of the siphuncular zone, crystals may form aggregations of considerable height (Figure 36); be- tween pillars, the first vertical organic sheets appear. Fi- Vol. 21; No. 3 nally, in the foremost part of the siphuncular zone, the growth of distinct crystals comes to an end, and we find only columnar pillars sustaining the organic floor. This is the area where horizontal sheets are found between the pillars (cf. above). These sheets become more continuous above the rearmost part of the calcified chamber floor, and there the pillars take on a wall-like appearance. The chamber height isapproximately thesame through- out the greater part of the chamber zone. Exceptions are the first chamber formed after hatching, which is often markedly lower, the zones of closely spaced chambers de- scribed by various authors (cf. BoLeTzKy, 1974a), and the last chambers of the adult, senescent animal (Figure 0). : The formation of the dorsal layer begins rather late in embryonic development. In Sepia officinalis, it first ap- pears in the form of an irregular crystal cover on the organic outer surface of the shell (Figure 37). In Sepia pharaonis, the first dorsal layer is made of nodular spher- ulitic structures (Figure go). During further growth, the spherulite sectors start on the dorsal side of the or- ganic central layer. The dorsal outer surface of the central layer is comparatively wide; the dorsal layer grows over it either by depositing directly ridge- or bump-like spher- ulitic structures that are surrounded by organic material (Sepia elegans, S. pharaonis), or with a zone of irregular fine crystal growth (Sepia officinalis, S. orbignyana). This may differ, however, among individuals as well as among different growth stages of an individual. Towards the central part of the dorsal shield, the crys- tals are arranged in ridge-like aggregations, with a spher- ulitic orientation (Figure 38). Addition of crystalline ma- terial alternates with periods where organic material is added, but this periodicity seems not related to the forma- tion of certain layers in other parts of the cuttlebone. Thus in a section or in a fraction, the dorsal layer shows varying sizes of crystal aggregates and different crystal diameters (Figure 44). Aggregates measuring 2mm in diameter can be found on the adult cuttlebone of Sepia officinalis. Crystal diameters vary from 0.2 um to 15 um. Near the spine or the structure corresponding to it (e. g., lamellar ridge in Sepia elegans), the dorsal layer is absent, as in S. officinalis, or it may surround the spine, as in S. orbignyana, or it is represented only by a very thin crystal cover of the ridge that represents the spine in S. elegans. In terms of its structure, the spine must be con- sidered as part of the central layer (Figure 41), although it generally starts forming on the embryonic dorsal layers (Figure 39). Finally, it should be mentioned that the structure of later deposits found on the posterior part of the siphun- cular area consists of spherulitic-prismatic crystals and THE VELIGER Page 317 thus can be compared to the dorsal layer (cf. below). The central layer is the earliest to appear during em- bryonic development, where it is represented by the protoconch and the early organic shell. In the marginal parts of the shell that are formed later, it is also mostly organic; it is composed of sheet-like smooth organic layers that have been deposited in a succession directed towards the margins. The central layer is thin near the protoconch; it gradually thickens anteriorly, and more so towards the margins. Its lateral portion is always purely organic, whereas in the ventral part calcareous material is inter- calated and interlocked with the organic sheets. Since the organic sheets that are added to the margins of the dorsal shield are not continuous with others, but are deposited on sheets formed earlier, they form a low angle with the plane of the central layer (Figures 2, 46). At 9000X magnification, the organic sheets show no other substructure than a striation with a period of 0.1 to 0.2 um. Towards the inner layer, very thin and long lamellar crystal rods and long needle-shaped crystals may grow along with the organic sheets. Within a short distance, purely organic layers can turn into calcified layers (Figure 42). The calcified part of the central layer is much thicker above the chambers than near the margins (Figure 2). In the central part, the inner layer shows a lamellar structure. These lamellae form a low angle with the plane of the central layer, like the purely organic lamellae closer to the rim (Figures 2, 46, 47). Lamellae are ca. Imm in thickness; they are continuous throughout the extent that we have been able to follow. They do not branch, but they change in thickness when turning into the purely organic zone (Figure 46). They also show some variation in their thickness close to the base of the inner layer where they end. Lamellation largely or entire- ly disappears where the base of the coarse prisms of the inner layer appears (Figure 47). Each lamella of the central layer is composed of rod- like elements which usually are identically oriented with- in one layer (Figures 48, 51). Among different lamellae, this direction may change. Sometimes the needle-like crys- tallites that compose the lamellae show a feather-like arrangement (Figure 4g), are gently curved (Figure 50) or branched (Figure 48). No distinct organic sheets ap- pear between lamellae, but organic and mineral (needle- like) shell material is interlocked with one another, thus forming one complex shell deposit of organic and mineral components. The construction of the lamellae in the cent- ral layer thus is similar to the construction of the lamellae in the septa and the fork layers. These strongly calcified parts of the central layer that are continuous in the ventral portion of the dorsal shield above the chamber zone extend, in some species of Sepia, Page 318 THE VELIGER Vol. 21; No. 3 onto the outer side of the dorsal shield where they build the spine and its surroundings. In S. elegans there is no distinct spine, but only a ridge made of organic lamellae, which are often covered by crystal aggregates of the outer layer. Sheets similar to those of the margins of the dorsal shield alternate with deposits of the dorsal layer. The shells of Sepia orbignyana and S. pharaonis have strongly calcified, solid spines (Figure 84). These con- sist of layers very similar to those of the inner calcified portion of the central layer. From the margins towards the center of the spine, lamellae become continuously thicker and show an increasing amount of calcareous material. Thus the spine is made of cone-shaped layers that are piled up on one another. Each of these cone layers, which are thickest in their center, is continuous with a purely organic layer at the sides of the spine (Fig- ures 41, 85). The actual spine is a purely lamellar struc- ture, whereas in its surroundings the organic layers cor- responding to the spine layers often are covered by materi- al of the dorsal layer so that they interdigitate with the latter (Figure 14). The structural features of the spine of Sepia officinalis are intermediate between those of S. elegans and S. orbig- nyana. In S. officinalis, the change from purely organic sheets of the central layer into the lamellar calcified layers of the spine is very abrupt (Figure 41). Thick organic sheets forming the margin of the posterior dorsal shield split into single sheets that connect the shield and the spine. Close to the spine, these layers again split into numerous free sheets, each of which is continuous with one lamella of the calcareous spine. In S. officinalis, the re- gion around the spine is covered with organic sheets, which may or may not show minor growth of crystals having the structure of those that build the neighboring dorsal layer. Certainly the layers that form the calcified spine in Sepia are part of the dorsal portion of the central layer; in other parts, e.g., in the marginal rim of the dorsal Explanation of Figures 28 to 43 Figure 28: Fracture through septum of the chamber zone of Sepia orbignyana, showing a pillar rooted on the prismatic chamber floor (lower, ventral side of septum). The chamber floor is composed of the lamellar structure X 1400 Figure 29: Transverse section through the chamber zone of Sepia gibba showing narrow chambers separated by septa which are held apart by pillars. Suspended between the pillars in the chambers are organic sheets. The upper margin of the figure is ventral X 28 Figure 30: Transverse fracture through the chamber zone of Sepia orbignyana showing the last formed chamber of an adult individual with decreasing chamber height. Note the organic sheets which are suspended within the chamber cavities between the pillars. The up- per margin of the figure is ventral x 180 Figure 31: Section through chambers of Sepia orbignyana in the siphuncular zone. Note in the lower chamber mostly round pillars close to the posterior end of this chamber. The upper chamber shows the anterior siphuncular area with short pillars. Above it the extreme posterior end of the siphuncular zone of the next chamber is visible, with irregular crystal growth and very short pillars. The siphuncular membrane is torn off and only its posterior portion is visible at the right. The upper margin of the figure is ventral xX 126 Figure 32: The siphuncular zone of a chamber of the embryonic shell of Sepia pharaonis during growth demonstrates the change of orientation of organic sheets from parallel to septa to vertical to septa. Also pillars become shorter and more numerous within the siphuncular zone X 190 Figure 33: This detail of Figure 32 demonstrates the change in orientation of the organic sheets within the chamber in the siphun- cular zone X 430 Figure 34: The posterior end of the siphuncular area of a chamber of the cuttlebone of Sepia pharaonis, showing the organic siphuncu- lar membrane (in the lower left), and where it is torn off the siphuncular zone of the chamber below it X 380 Figure 35: This detail of Figure 34 shows the crystals of the posterior portion of the siphuncular zone with well-developed crystal faces X 8000 Figure 36: Another detail of Figure 34, with aggregations of crys- tals forming pillar-like structures that lie between short pillars in the central region of the siphuncular zone X 4000 Figure 37: The first irregular crystal cover on the organic, outer (dorsal) shell surface in the embryo of Sepia officinalis X3 700 Figure 38: A fracture through the central portion of the dorsal shield of Sepia orbignyana showing the lamellar central layer (lower part of figure) and the spherulitic dorsal layer. The latter forms ridges and crests on the dorsal side of the cuttlebone X 420 Figure 39: Crystal growth on the posterior portion of the embry- onic shell of Sepia officinalis at first is spherulitic, like that of the dorsal layer. Only later is it changed into the lamellar structure forming the spine at this location X 1600 Figure 40: The dorsal layer in the posterior rim of the dorsal shield of the shell with 6 chambers in young of Sepia pharaonis consists of isolated spherical structures X 370 Figure 41: A detail of Figure 85 of the spine of Sepia officinalis demonstrates the rapid transition from organic sheets of the spine cover into the lamellar, calcified structure of the spine. The thick organic sheets split into thin lamellae near the calcified spine X 194 Figure 42: The central layer of Sepia orbignyana, broken parallel to the growth surface, shows the rapid transition from mineralized, lamellar structure to purely organic sheets X 4200 Figure 43: Crystal needles are present in the mainly organic de- posits covering the posterior portion of the siphuncular area of the adult shell of Sepia pharaonis X 3.900 Tue VELIcER, Vol. 21, No. 3 [BANDEL « BoLerzxy] Figures 28 to 43 ~ f a ! va qn c.eeet Wiis i 30 NE, | 7 ges : hd “ua . Vol. 21; No. 3 shield and the area surrounding the spine, this central layer may be calcified to a much lesser extent or not at all. On the ventral side of the shield. the inner layer comes very close to the margin; it overlaps the central layer. On the innermost organic sheets of the central layer, close to the prismatic base of the inner layer, there are more ir- regular needle lamellae. The needles merely show a general orientation according to a common direction; they are loosely spaced. so that there are interstices between them (Figures 49, 50). They may also be oriented in such a way that they form whorls that unite into columnar structures (Figure 50). In additional layers, closer to the base of the inner layer, such whorls turn into the round spherulitic nodules(5 4m wide) that form the base of the prismatic inner layer (Figure 47). The inner layer covers the ventral side of the dorsal shield from near the border of the uncalcified organic rim to the border of the fork layer (Figure 1). Only some of the innermost layers of the outer rim of the shield are calcified; they gradually turn into the inner spheru- litic prismatic part of the inner layer, as shown above. The inner prismatic layer consists of coarse prisms that have an irregular outline (Figures 46, 47). In a section par- allel to the growth face, the prisms form an irregular network with a mesh width (diameter of prism) of about 5 um. When viewed from the growth face, near the inner rims of the dorsal shield, the growing inner, prismatic portion of the inner layer shows well developed crystal faces (Figure 52). The crystal needles are not arranged strictly vertical to the growth face; they may unite into columnar units of spherulite sectors (Figure 53). Further inside the inner rim of the dorsal shield, crystal size decreases, and the even growth of crystal heads is changed into a more nodular growth of crystal bundles; the components show less distinct crystal faces (Figure 55). In section, one notes a spherulitic prismatic orientation of the needle crystallites, which are now much thinner. Co- lumnar structures consisting of crystal needles inclined towards a central axis form this lower layer (Figure 53). This lowermost (ventral) layer is only found beside the chamber layers, not above them (Figure 2). Above the chambers, there is a coarsely prismatic to spherulitic pris- matic layer; its thickness decreases towards the medial part of the dorsal shield. Thus an oblong, oval field in the medial part of the dorsal shield is devoid of an inner layer. This oval field, which is broader anteriorly, is “left out” when the inner layer is formed on either side of the chamber layer (7. e., not on the anterior rim of the newly formed chambers) (Figure 1). Here the calcified central layer forms the basement for the anterior portion of newly formed chambers. TBE VERIGER Page 319 The borderline between the inner layer and the fork layer is sharp and usually is marked by a furrow (Figure 55). Sections through the contact region between the inner and the fork layer even show cavities; these are bridged by organic sheets indicating the course of growth lines (Figures 2, 54). The region of contact between the inner and the fork layer shows signs of alternating ap- proach and retreat of these layers during the secretion of the cuttlebone (Figure 2). The zone of transition from the inner layer towards the central layer shows a more gradual change, especially where the medial parts of the dorsal shield grade into the strongly calcified inner part of the central layer (Figures 46, 47). A gradual change between these layers is also found near the rim of the shield, but is restricted to the width of a few lamellae (Figure 50). The fork layer is broadest and thickest in the posterior part of the dorsal shield. Its anterior ends often thin out before they reach the siphuncular area of the last-formed chamber; they may also extend beyond it. There does not seem to be a direct continuation of fork layers into cham- ber septa. Since the fork grows in length only anteriorly, its layers are piled up on one another. In adult Sepia, 12 to 15 such layers with a maximal thickness of 25 um may be present on the ventral side of the cuttlebone. In their thickest part, these layers are made up of roughly 40 lamellae (Figure 59). These lamellae are composed of minute needle crystals (0.3 um in width), which are uni- formly oriented within a lamella (Figure 56). Separation of thicker layers is due to the presence of more organic lamellae between the calcified ones that form the thicker layers (Figures 56, 59). On the margins of the fork, each layer extends to a different degree onto the chamber zone, on the one side, and onto the inner layer, on the other side (Figure 2). A more strongly mineralized layer shows a growth front consisting of flattened rod-like needles that encroach, in the form of a sheet, upon the basement (Figure 58). There is only in some places a uniform orientation of the needles, as many lamellae grow at the same time, so that their fronts overlap one another. In mainly organic parts of the fork layer, the needle-like crystals are regularly arranged and maintained within organic sheets, where they are covered and surrounded by organic shell materi- al (Figure 59). In the posterior part of the siphuncular area, adult individuals of Sepia officinalis and S. orbignyana often show tubercular deposits that consist of aragonitic needles in a spherulitic prismatic orientation, like those found in the dorsal layer. Thus the siphuncular membrane of the oldest chambers, which are refilled with liquid, becomes impermeable. Page 320 In Sepia pharaonis, a crescent-shaped deposit consist- ing of a thick layer of mainly organic sheets is secreted on a very prominent tubercular deposit in the posterior part of the siphuncular area (Figure 4). Within these Figure 4 Ventral view of the posterior part of the cuttlebone of Sepia phara- onis. The rear end of the siphuncular zone (belonging to the ear- liest chambers) is covered by a crescent-shaped deposit that con- sists of mainly organic layers with calcitic and aragonitic crystals. sheets there are mineralized spots. This is the only case where calcitic crystals exist besides aragonitic ones in the shell of Sepia, as has been demonstrated by X-ray dif- fraction. The needle-shaped crystals are distributed in distinct spots of irregular outline; they lie parallel to the plane of the organic sheets and generally parallel to one another (Figure 43) (cf. also AbaM & REEs, 1966: plt. 8). It should finally be emphasized that the intricate sys- tem of organic sheets and threads interspersed with the calcareous structures is only partly chitinous. JEUNIAUX (1963) has analysed the shell of Sepia officinalis and found that 4.4% of the chambered zone is organic. Of this portion, only about 4 is chitin. This author also indi- cates that the dorsal shield contains chitin (cf. also Rup- ALL & KENCHINGTON, 1973). Morphology and Structure of the Shell in Spirula The shell of Spzrula was first described in detail by APPEL- LOF (1893) and more recently by Mutver (1964a) and THE VELIGER Vol. 21; No. 3 DaupHIN (1976). Scanning electron microscopy was used for the study of the septal layers by MutTVEI (1970), ERBEN (1974) and DaupHIN (op. cit.). Our de- scription is therefore largely restricted to features of the Spirula shell that were not described or mentioned in the earlier literature. The initial chamber of the shell is almost spherical. It is only slightly higher (0.7mm) than wide (0.5 -0.7 mm). Nearly the entire wall consists of a single layer, since nodular deposits of the outer layer are sparse and are entirely restricted to the anterior dorsal side of the initial chamber. The wall of this chamber has a thickness of 10pm; it consists of a very regular prismatic layer (Figures 64, 66). The needle-shaped crystallites composing this layer are arranged parallel to each other and vertical to the inner and outer surfaces of the chamber. In the prismatic layer one can distinguish an outer and an inner part (not including the spherulitic-prismatic structure of the dorsal layer, which is added later). The outer layer is rich in organic material, whereas the inner layer shows fewer organic deposits. The surfaces of the inner and outer layer are devoid of any organic cover. The apertural end of the first chamber is 0.38 mm wide; it shows a strong constriction which is much more pro- nounced than the constrictions between later chambers. The apertural lumen is taken up entirely by the siphun- cular tube; the latter is inserted on the inner walls of the constriction and extends into the lumen of the chamber (Figures 64, 66). The end of the siphuncular tube is con- tinuous with an organic sheet that is fixed to the opposite wall of the chamber (Figures 64, 65). Between the pris- matic outer wall of the constriction and the insertion of the siphuncular tube lies a prismatic ridge (Figures 66, 73). The side of this ridge that slopes into the first cham- ber shows more organic material in its fabric than the opposite side. Crystallites are arranged vertically to the surface of the ridge. From inside the first chamber, this ridge appears as a low rim that surrounds the siphuncular tube, from which it is separated by a deep, narrow de- pression (Figure 64). From the constriction (aperture of the first chamber), the siphuncular tube decreases apical- ly in diameter until it reaches its extended tubular end which is about 0.1 mm wide. The pear-shaped siphuncular tube is inclined towards the ventral side of the chamber. The calcified portion ex- tends into the chamber for about 0.3 mm. It is composed of lamellar layers in the structure of the septa that are formed later on (Figures 66, 73). This tube is generally closed by a hemispherical cap that is continuous with the organic sheet mentioned above. The longitudinal wrinkles of the sheet continue into wrinkles that cross the organic cap in a radial orientation (Figures 5, 65). Vol. 21; No. 3 THE VELIGER Page 321 Figure 5 The first chamber of the Spirula shell opened up, exposing the earliest part of the siphuncular tube with its wrinkled surface, and its attachment to the inner wall via the organic sheet that is roughly spatulate. The site of attachment presumably marks the protoconch area The organic cap may continue into the mineralized portion of the siphuncular tube without any break in its outline. But it may be altered in its structure when it has collapsed and the resulting shape has been fixed by the addition of organic material (Figure 87). More com- monly, however, the diameter of the cap is slightly smal- ler than the diameter of the uppermost part of the cal- careous tube, so that the transition from one structure to the other is marked by an edge (Figures 64, 66). The wrinkles mentioned before cross this edge and continue in the outer organic cover of the calcareous siphuncular tube. After the primary siphuncular tube of the first cham- ber (which is devoid of a septum) is completed, the nor- mal growth of the shell begins with the formation of sep- ta and the siphuncular tube. In contrast to later sections, however, in the second section of the siphuncular tube the pillar zone is extremely short (Figures 66, 68). The outer wall of the Spirula shell consists of 3 layers, except for the first chamber (Figure 67). The outermost, dorsal layer may or may not be continuous on the dorsal side; it has a sculpture of nodular structures. On the ventral side, the dorsal layer is continuous; it consists of prismatic to spherulitic needle-like crystallites. The main portion of the shell wall is represented by the central layer (Figure 67). In polished sections viewed under the light microscope, it appears to consist of a prismatic struc- ture with many parallel organic lamellae that cross the prisms, parallel to the inner and outer surfaces of the shell (cf. Murtvei, 1964a: plts. 17, 18, fig. 2). In frac- tures, this layer shows a construction of small granular to brick-like crystallites that are not arranged in vertical needles; they present a slightly irregular arrangement in lamellae that lie parallel to the growth face (Figure 72). Single crystallites are about 0.4 wm long and 0.2 um high; they are always enveloped by organic shell material. The construction of the central layer very much resembles A longitudinal section through the outer wall of the Spirula shell, at the insertion of a septum (s) on the coarsely prismatic inner rim (ir). The outer shell wall consists of the outer, irregularly pris- matic layer (ol), the central, lamellar layer (cl), and the inner, prismatic layer (il). The arrow points towards the aperture Page 322 that of the columnar siphuncular pillars (cf. below). The central layer forms more than half of the outer wall. It grades into an inner prismatic layer of somewhat vari- able thickness (Figure 67). This change is characterized by the arrangement of the crystallites in vertical needles of continuously increasing width towards the inner sur- face of the chamber. In tangential sections, these needles show up as a polygonal network (cf. Mutvel, 1964a: pit. 18, fig. 2). Where the septa are inserted on the outer wall of the shell, the inner layer shows a particularly coarse prismatic structure (Figure 6). It forms an inner rim that reinforces the constriction of the chamber aperture (Figure 88). The septum consists of a lamellar needle layer. At the insertion on the outer wall, the inner side differs in its structure from the outer side. The inner side (facing the newly closed chamber) is marked by an abrupt ending of the lamellar needle layers (Figures 6; 88). They are in- serted on the prismatic ring mentioned above, which is THE VELIGER Vol. 21; No. 3 similar to the additional constriction formed at the aper- ture of the first chamber (Figures 66, 73). On the apertural side of the septum, lamellae extend further anteriorly, on the inner surface of the newly formed chamber (“living chamber”) (Figure 6). The growth surfaces of the last-formed septal layers show a gradation from fine crystallites on the septum to coarse crystallites towards the inner prismatic Jayer of the wall that follows anteriorly. The outermost layer of the septum is lamellar, but the orientation and the composition of the needles are not as regular as in the layers next to it. The lamellae of the septum, from the first formed one to those lying under the last formed lamellae, consist of needle crystals that have a width of 0.2 wm and show the same orientation within a lamella. The thickness of each lamel- la is given by the width of the single layer of needle crys- tallites and their organic cover. Although the orientation of crystals may change from one lamella to another, one sometimes finds series of lamellae in which the crystals Explanation of Figures 44 to 59 Figure 44: A section through the dorsal layer of the cuttlebone of Sepia orbignyana showing the irregular spherulitic structure X 335 Figure 45: A detail of Figure 74 showing the first mineral deposits on the dorsal side of the embryonic shell cap of Sepia officinalis that raise the contrast of radial sculpture and transversal growth lines xX 140 Figure 46: Section through the cuttlebone of Sepia orbignyana shows the transition from the lamellar structure of the calcified por- tion of the central layer to the columnar base of the prismatic inner layer X1 800 Figure 47: Detail of Figure 46 shows the rapid transition from the central layer (lower part of figure) to the inner layer X 4600 Figure 48: Calcified central layer of Sepia officinalis, broken nearly parallel to lamellation, demonstrates the composition by rod-like crystallites X 4700 Figure 49: A feather-like arrangement is present in the central layer of the Sepia orbignyana shell, broken parallel to the growth surface, near the outer side of the shield and close to the transition into the inner layer. The needles are loosely spaced X 4000 Figure 50: Crystallites of the central layer in almost the same posi- tion as in Figure 49, forming whorls that unite in columnar struc- tures and form the base of the coarse prisms of the inner layer X 4000 Figure 51: The central layer of Sepia officinalis, broken nearly par- allel to the lamellation, demonstrates its composition of small rod- like crystallites composed of small basal units of 0.1 to 0.2 pm in Size X 5 000 Figure 52: Growth surface of the lower portion of the inner layer in the shell of Sepia orbignyana, near the inner rim of the dorsal shield, with well-developed faces X 4500 Figure 53: The inner layer of the cuttlebone of Sepia orbignyana showing below the dorsal coarse, prismatic portion and above the ventral finer, spherulitic-prismatic portion X 930 Figure 54: A section through the fork layer (right) and the inner layer (left) of the shell of Sepia orbignyana shows the sharp border between both layers and cavities separating them, bridged only by organic sheets X 270 Figure 55: The boundary between the inner layer (right) and the fork layer (left) in the shell of Sepia orbignyana is formed by a deep groove on the growth surface X 880 Figure 56: The fork layer of Sepia gibba is composed of needle- like crystallites surrounded by and intergrown with organic material. Needles of each individual layer show the same orientation, but this orientation may differ among layers X 4500 Figure 57: Detail of Figure 84 shows the orientation of the first crystal growth near the spine of Sepia pharaonis, in an animal ready to hatch. Crystal needles have the same orientation within each aggregate, but are not yet oriented as regularly as within the lamellar structure of the spine itself X 7800 Figure 58: The growth surface on the central portion of the fork of Sepia orbignyana shows flattened, rod-like needles encroaching upon its surface X 3 800 Figure 59: The fork layer of Sepia officinalis in a fracture shows the fine lamellation formed by 0.2 um thick layers composed of crystal needles and organic sheets. Some thicker organic sheets ex- tend over the fracture and are hanging down from it X 2300 [BANDEL « BoLterzky] Figures 44 to 59 THE VELIGER, Vol. 21, No. 3 Vol. 21; No. 3 THE VELIGER Page 323 are all oriented identically. They are always well separa- ted by organic material (Figure 62). On the apertural surface of the septum, the lamellar crystal growth is more dendritic (Figure 60). Single la- mellae tend to split into 2 lamellae by dendritic branching of crystal needles, with the thickness of needles remaining similar (0.2 um) to that observed in deeper layers. ‘To- wards the periphery of the septum (apertural side), needles and rods or prisms are oriented along 2 to several axes (Figure 61). The crystallites then become much wider and the crystalline faces become clearly visible. Further away from the septum, the size of crystals may remain unchanged, but lamellation completely disappears and is replaced by a vertical arrangement of needles. The orien- tation of growth increments on the crystal heads in 2 or several directions gradually disappears until a random pattern is established in the normal inner prismatic layer. The layers of the septum are continuous with the si- phuncular tube. The structure of the lamellar needle layer of the outer wall of the tube, which we find already in its blind end (Figure 66), continues through the chamber. Only below the septal neck of the following septum, the lamellar layer splits into 4 parts (Figure 7). The outer- most layer is continuous with organic sheets. In newly formed, closed chambers, these organic sheets form a layer that closes the entrance to the space in which the pillars lie (Figure 69). These pillars are rooted on the inner side of the siphuncular tube, the foremost (aper- tural) ones being set on the concave surface of the sep- tum where it turns into the septal neck. Their growth ends with the formation of the posterior part of a new siphuncular tube (Figures 68, 70). Organic sheets extended between the pillars are found only in the apertural part of the pillar zone (Figure 7). From the innermost lamellar layer of the last formed siphuncular tube, pillars always grow up without any Figure 7 A horizontal section through the siphuncular tube of Spirula. The layers of the septum (s) continue into the siphuncular tube. At the entrance to the septal neck of the next older septum, the lamellar layers split into organic sheets (0) that shut up the pillar zone (pz), organic sheets and pillars of the entrance, pillars of the middle pillar zone, and finally into the organic and crystal cover (cc) of the pillar zone. The arrow points towards the aperture. Page 324 THE VELIGER Vol. 21; No. 3 separation by organic sheets. The shape of the pillars varies, however, according to their respective position along the siphuncular tube. In the anterior zone, they form solid structures of bi- conical appearance with terrace-like annulations; they are broadly rooted on the bend of the septal neck and on the apertural part of the siphuncular tube (Figure 70). In front of complete pillars, small mounds and half grown pillars with the typical annulations are found. The foremost complete pillars show only ro to 15 annulations or growth zones, each of which is the continuation of one lamella of the anterior part of the tube. In this part, the lamellae may measure up to 15 zm in thickness. The free space between pillars is about equal to the diameter of these. On the inner siphuncular tube (the “floor”), the ends of the pillars fuse to form a solid, non-porous tube (in the anterior-most part of the pillar zone only!) (Figure Tp) e d Further inward, pillars have a more columnar shape and smooth surface, on which 50 to 60 lamellar layers can be counted (Figure 86). These are continuous with lamel- lae of the central part of the anterior siphuncular tube. Spaces between pillars are much wider than in the ante- rior pillar zone; they correspond to twice the diameter of a pillar. The lamellar structure of the base of columnar pillars is similar to the central layer of the outer shell wall. It consists of short needle- or brick-shaped crystals that are arranged vertically to the axis of the pillar (Fig- ure 63). In contrast to the pillars of the anterior pillar zone, the pillar ends do not form a solid cover of the inner siphuncular tube. Instead, the radiating crystals and crys- tal aggregations form an interlocking system with many small spaces (Figure 71). In these, numerous thin organic sheets are transversally suspended. This porous layer of interlocking needle aggregations is covered by a smooth, thick organic sheet. The fourth (inner) section of the lamellar layer of the anterior tube is continuous with this uncalcified layer; it forms the innermost part of the shell that is in direct contact with the living tissue of the si- phuncle. The transition from the calcified lamellae of the anterior tube to the organic inner layer is quite abrupt (Figure 7). Further inward, towards the end of the inner tube, pil- lars are very short and drum-shaped; the interlocking crystal aggregations are growing into the spaces between the pillars. A section through a double-walled siphuncular tube thus shows 4 layers: an outer lamellar layer, the pillars, the interlocking needle aggregations, and the inner organ- ic layer. The anterior tube of the last septum shows a single wall that consists of the lamellar layer only. The 3 inner layers are added when the next septum is formed (Figure 7). It should be noted here that the inner organ- ic layer is destroyed by acids, whereas the organic com- ponents of the layers with lamellar structure are resistant. The formation of a new septum and siphuncular tube section can be figured in the following way. First of all, the animal has to begin the outer wall of the new cham- ber (DENTON & GitPIN-BRowNn, 1971). Then an annular prismatic ridge is formed at the border between the old and the new chamber, so that the constriction between them is reinforced. Meanwhile the tissue of the siphuncle must have grown to a sufficient density to be stretched over the length of one chamber. When the living tissue withdraws from the old chamber, it produces organic sheets that cover the wall left behind. When all the tissue has withdrawn, these organic sheets entirely cover the walls of the liquid-filled space. Now calcification begins, from the septal rim all through the septal neck into the siphuncular tube of the older chamber. The organic cov- ers of the septum and the anterior siphuncular tube are integrated into the first lamellar layers, so that they can no longer be traced. As we have said above, free organic sheets will cover only the outer walls and the apertural side of the (old) septum and close the aperture between the anterior and posterior part of the siphuncular tube when the tissue withdraws from the “living chamber.” Apparently the first lamellar layers deposited on the rear flanks of the prismatic ridge are secreted at the same time as the lamellar layers in the anterior part of the tube, the thick layers of the anterior pillar zone (with intercalated organic sheets), and the thin lamellae at the base of the pillars in the middle zone. The medial parts of the sep- tum and the anterior tube form along with the upper por- tions of the anterior pillars that are fused into a calcareous ring, and with the upper portions of the medial pillars. The growth of the last septum layers is connected with the formation of the irregularly prismatic, porous layer and the first layers of the organic, soluble inner sheet. The septum is now completed, whereas in the siphuncular tube calcareous and organic lamellae continue to form at lower rates of growth until a new chamber is added. With the completion of the septum, the newly closed chamber can be used as a buoyancy element. Development of the Shell Complex in Sepia The early development of the shell complex in Sepia embryos has briefly been described by APPELLOF (1893), and observations made by earlier authors are discussed there. A handicap of all these descriptions was the lack of a comprehensive staging system. The relation between morphogenetic processes and differentiation in different Vol. 21; No. 3 parts of the embryo does not clearly show up, therefore. It was a great advance when NaeEF (1923, 1928) intro- duced a good system of embrvonic stages (stages I to XX). On his figures one can follow a great part of the complex morphogenetic processes by which an originally thin cap of embryonic tissue (the typical blastodisc of the teloleci- thal cephalopod egg’ takes the form of a compact organ- ism. In the center of this embryonic cap, the future shell epithelium can be made out at very early stages. It is surrounded by an annular thickening, which is the rudi- ment of the muscular mantle. In all decapod cephalopods (cuttlefish and squids) so far studied, the subsequent process of the closure of the shell sac rudiment is essentially identical. First an annular ridge forms at the periphery of the mantle epithelium. This ridge then becomes a fold which grows centripetally over the mantle epithelium. The central opening of this mantle fold becomes slightly cornered, with one anterior (dorsal) and 2 lateral angles, before the shell sac is closed. The “scars” of the anterior and lateral angles will later differentiate into the so-called organ of Hoyle, which acts as a hatching gland. As soon as the shell sac is closed, at stage XI of Naef, formation of the embryonic shell begins. The histological aspects and the general differentiation of the early mantle epithelium and of the closed shell sac have recently been described by Spiess (1972). His description ends with stage XVI when histological differentiation is still in prog- ress. Some complementary remarks must therefore be made for the later embryonic stages, and in some respects also for the earlier stages described by this author. The following brief description is based entirely on our own observations. At the earliest stage of shell sac formation (stage VIII of Naef), the flat shel! epithelium is characterized by roughly columnar cells, which are much higher in the anterior and middle parts of the epithelium as compared to the posterior part. The nuclei lie closer to the cell base, so that the apical parts of the cells together form a “plasma border”; the latter contains numerous vacuoles. In the middle and anterior parts of the epithelium, the nuclei of the closely packed cells lie at different levels, so that in these parts of the epithelium 2 or 3 layers of cells would seem to exist. However, there is no horizontal strat- ification of the cells. This primary shell epithelium is clearly separated from the underlying mesoderm. The further development of the annular ridge, which already takes the shape of a fold by stage VIII, leads to the formation of the so-called “secondary shell-epitheli- um,” which will be the “ceiling” of the shell sac. From histological sections, it appears that this lower (inner) cover of the closing fold is stretched during the closure TGEMVERIGER Page 325 of the shell sac. Mitotic figures observed close to the open- ing show, however, that cell division continues also in this inner part of the fold. This means that the secondary shell epithelium forms in situ from ectodermic cells given off by the parts derived from the early annular ridge. This sec- ondary shell epithelium remains thin, with its flattened nuclei widely separated. Its thickness gradually increases towards the periphery of the shell sac, 2. e., in the zone of transition to the primary epithelium. By stage IX, the greater part of the primary shell epi- thelium is covered by the closing fold (the latter is filled with mesodermic cells that form a rather loose “mesen- chyme”’). Complete closure of the shell sac occurs between stages X and XI. The closing pore lies in the posterior part of the sac, about 4 of its length from the posterior end. The closure of the shell sac is coordinated with the gen- eral contraction of the embryo cap. The organ rudiments which had been lying in the single plane of the thin cap are now “assembled” in a three-dimensional arrangement, which largely corresponds to the definitive organisation of the animal. During these stages of assembly, the pri- mary eye vesicles and the statocysts close, the stomodaeum is invaginated, and the funnel and mantle margins rise as distinct folds. The mantle complex thus takes its cup shape. The shell sac, which occupies the dorsal part of the mantle complex, remains comparatively flat, but its posterior and lateral parts are slightly bent to the ventral side. The initial shell or protoconch, which is secreted im- mediately after closure of the shell sac, is roughly spoon- shaped, with its deepest part near the posterior end. It is a simple organic membrane, without any growth lines, about 0.9mm long and 0.7mm wide. During the follow- ing stages, organic material is added to the margins of this protoconch. The outline of the shell becomes ovoid. Along with the deposition of more organic shell material, the posterior slope of the embryonic shell becomes steeper, until an angle of about go° with the plane of the anterior dorsal shield is attained. Around stage XII, the posterior edge bends and grows outwards into a brim. This differ- entiation of the shell sac is related to the differentiation of the mantle muscle (on the ventral side), as the latter is inserted on the lower face of this brim (Figure 15). Up to stage XI, the shell sac shows no signs of any local excrescence or folding of either one of the epithelia. Around stage XII, however, both the primary and second- ary epithelium present such phenomena. In the posterior part of the shell sac, the secondary epithelium forms a lateral diverticulum on either side, in contact with the base of the fin rudiment. This process has been mentioned briefly by NaEF (1922). The lateral Page 326 THE VELIGER Vol. 21; No. 3 pockets thus formed (Figure 10) correspond to those de- scribed in the sepiolid Rossia macrosoma (BOLETZKY & BoLETzKY, 1973), where the uncalcified shell is extremely reduced. Thus, independently of the presence or absence Figure 8 The early embryonic shell (protoconch) of Sepia officinalis often shows a ventral ridge or fold that is formed by the longitudinal fold of the primary shell epithelium shown in Figure 95 of a shell in the area of the fin base, the fin cartilage forms on the outer wall of these pockets. The primary epithelium forms a groove that can be- come a very distinct deep and narrow slit, in which a ridge-like fold of the embryonic shell is anchored (Figure 8). It is not yet clear whether this acute form of epitheli- al depression does not occur in all embryos, or whether it is a short-lasting phenomenon that may occur sometime between stages XII and XIII; in fact, only part of the embryos preserved at these stages present a deep groove. Except for a very small infolding of the siphuncular epi- thelium, in which a tiny lobe of the first septum was an- chored, this sort of groove has not been found after stage XIII. From stage XII to stage XIV, the mantle and the shell sac grow considerably, and the primary shell epithelium becomes thinner. If large parts of it have appeared 2- to 3-layered at stage XII, most of it is clearly mono- layered epithelium by stage XIV. It is conceivable that this rapid stretching is partly prepared by the formation of a groove that would represent a “surface reservoir.” The apparent irregularity of this process is not so sur- prising if one considers the range of variation in the other Explanation of Figures 60 to 73 (Figures 60 to 73 are taken from Spirula shells) Figure 60: View onto the apertural surface of the septum demon- strates lamellar crystal growth with somewhat dendritic components X 8 800 Figure 61: Septum broken nearly parallel to the growth surface shows the lamellar layers composed of needles arranged parallel to each other within each layer, but not so in neighboring layers X 1500 Figure 62: View onto the peripheral portion of the apertural side of the septum shows continuously coarser crystals transitional be- tween the lamellar structure and the prismatic structure X 3900 Figure 63: Detail of Figure 86 showing the short brick-like crystals that are arranged vertical to the axis of the pillars which they com- pose X 9 500 Figure 64: The opened initial chamber of the shell showing the blind end of the siphuncular tube that continues as an organic sheet fixed to the opposite wall of the chamber X 108 Figure 65: The end of the siphuncular tube with its organic cap that continues as an organic sheet X 1000 Figure 66: The end of the siphuncular tube comprises the organic cap and the calcified portion with lamellar structure (detail in Figure 73). The tube is fixed to the outer prismatic shell wall in the constriction between the first and second chamber by a pris- matic ridge (central right side). The inner tube of the siphuncle is filled with a secondary organic deposit X 320 Figure 67: Section through the outer shell wall with the outer prismatic layer on the lower side of the picture and the coarse inner prismatic layer at the upper side. The lamellar central layer forms the bulk of the shell X 550 Figure 68: The entrance into the pillar zone of the second portion of the siphuncular tube extending into the blind initial section of the siphuncular tube already shows the typical apertural pillars, as at later stages. The length of this first pillar zone is much smaller than in later sections, however X 350 Figure 69: A septum with its septal neck is broken to show the continuity of the siphuncular tube extending into it. At the en- trance into the pillar zone, organic sheets are seen that had sepa- rated the liquid held in the pillar zone from that present in the chamber X 130 Figure 70: The entrance to the pillar zone is formed by biconical solid pillars with 1o to 15 annulations; note free space between them. Their end on the inner siphuncular tube is fused to form a solid layer (see Figure 77). X 175 Figure 71: The inner side of the inner siphuncular tube below the entrance to the pillar zone shows the solidly fused pillar ends against the (apically) following porous crystal cover of the pillar zone X 1500 Figure 72: Detail of Figure 67 showing the central portion of the outer shell wall that is composed of small brick-like basal units in a lamellar structure X 4500 Figure 73: Detail of Figure 66 demonstrates the lamellar structure of the end of the siphuncular tube (left). The latter is attached to the prismatic outer wall (right) by a coarsely prismatic ridge X 660 [BANDEL & BoLeTzxy] Figures 60 to 73 THE VELIGER, Vol. 21, No. 3 - rE. re eR f ty 2% EF 2 ay Vol. 21; No. 3 morphogenetic processes going on in the embryo. All through these stages of later organogenesis, one will rare- ly find 2 embryos that are exactly identical in their mor- phological features. The fast growth of the shell sac is reflected by the in- crements that are broadest in the anterior part of the shell; they measure between 0.03 and 0.08mm each. In addition to these growth lines, there are several other mor- phological features that characterize the purely organic shell between stages XIII and XIV. In the posterior part (protoconch area), a longitudinal groove or a pair of grooves can be made out (Figure 9). The corresponding Figure 9 A later stage of shell formation in Sepia officinalis, before the onset of calcification. The protoconch area is marked by a depression that is surrounded by radial wrinkles. Along the growth lines, pairs of grooves appear, combined with radial ridges form of the shell epithelium has apparently resulted from the folding and stretching processes mentioned above. The depressions in the shell are sometimes surrounded by radi- al wrinkles; occasionally there are also concentric wrinkles (Figure 9). On newly added portions of the organic shell, one finds radially arranged sculptural ridges. These be- come increasingly distinct with the growth of the organic dorsal shield. More laterally, one finds grooves that are THE VELIGER Page 327 generally forming pairs arranged along the growth lines. Seven to 11 such pairs of crescent-shaped depressions have been found on different embryonic shells just before the onset of calcification (Figure 74). In the organic shell of embryonic Sepia pharaonis, these morphological features were not found. There is only a central depression or a pair of depressions in the protoconch, and at later stages the shell shows only growth lines. During the phase of mainly marginal shell growth de- scribed above, the marginal zone in the anterior and lateral parts of the primary epithelium is characterized by particularly high cells. This rim of columnar cells re- mains a typical feature of all the later stages of shell formation (Figures 11, 18). Calcification of the embryonic shell begins between stages XIV and XV, when the shell has a length of about 2.3mm. The first aragonitic layer is formed on the inner, ventral side of the shell, which it covers entirely except for a narrow marginal rim; the sculpture of the organic shell is thus fixed in its form. The radial ridges on the dor- sal shell surface become distinct (Figure 45). In its first phase, calcification is restricted to the ven- tral side of the dorsal shield, where a continuous layer of minute aragonite crystallites that form needle lamellae is deposited. This is the basement for the first pillars that are formed around stage XV. In histological sections, the embryonic shell is usually distorted and often partly broken, and the closed shell sac balloons during fixation. It is often difficult therefore to relate shell structures to morphological and cytological features of the shell sac epithelium. However, the site of pillar formation is generally marked by a depression in the epithelium, so that it is easy to reconstruct the original position of the shell if it is well preserved. The question is whether these depressions reflect an actual cytological differentiation into “pillar forming cells,’ or whether they are insignificant or even artificial, the depressions being merely imprints of the pillars (preserved during the early part of fixation, before the shell sac expanded). Our observations suggest that these depressions are not signifi- cant for the mode of pillar formation. For these observa- tions, it is crucial to have encountered optimal conditions of fixation, so that the shell structures are well preserved. If the last-formed section of a chamber has, at least partly, been covered by an organic membrane when the animal was fixed, the “liquid” contents of the cavity next to the primary epithelium may be preserved in their orig- inal state. One then finds a stratification, which can only be made out by the refractive lines that mark the inter- faces of the unstained layers (Figure 12). Thus there appears to be a stepwise secretion of the medium in which Page 328 THE VELIGER Vol. 21; No. 3 Vol. 21; No. 3 Figure 10 An embryo of Sepia officinalis at stage XVI of Naef. The pallio- visceral complex is reconstructed from cross-sections. Of the visceral mass, only the inner yolk sac (iys) is represented as the lowermost organ visible in this dorsal view of the body. The uppermost parts are the fins (f) with their basal pockets (bp) that are a differenti- ation of the secondary shell sac epithelium. In the shell sac, the embryonic shell is represented with its first complete chamber (broad oval line, at left), and the posterior part of the outline of the second chamber in formation (dotted line, at left). The broken line with dots marks the depth of the nuchal pouch (np). The in- sertion of the head and funnel retractors on the marginal part of the primary shell epithelium is marked by dark stippling (hfr). The mantle muscle (mm), the funnel pouch or collar (c) and the stellate ganglia (sg) are also indicated. The pairs of arrows indicate the plane of the section presented in Figure 11A and in Figure 15A. At right, the shell is represented with its first chamber and the out- line of the second chamber in formation (broken line). The adhering primary epithelium is represented by the stippling, darker parts marking high columnar cells, lighter parts lower cells. The oval dashed field in the posterior part indicates the typical siphuncular epithelium (< on facing page) the pillar lamellae crystallize, layer after layer. The fact that the unmineralized part of these layers is preserved suggests that they are gelatinous for some time after they have been secreted by the epithelium. These observations support the hypothesis put forward by BANDEL (1977a), according to which nacreous and lamellar layers form via a gelatinous phase. On the solid, mineralized basement covering the ventral side of the embryonic shell, the first round pillars are set. (< on facing page) Figure 11 Cross section from the embryo shown in Figure 10 (camera lucida drawings). A: an entire section of the posterior part of the body (cf. arrows in Figure 10). The vertical expansion of the shell sac with the shell is an artifact. The arrow lines B and C mark the parts represented in the detail views (other abbreviations as in Figure 10). B: marginal part of the shell sac. The arrow indicates the limit between the secondary (left) and the primary shell epithelium (right). Note the similar height, but different aspect of cells in the marginal zone forming the organic rim and the middle zone (C and right part of B) where chambers are formed. C: the chamber forming epithelium shows a particularly distinct brush border (bb) with very long microvilli. Under this epithelium lie extensive blood spaces (bs) THE VELIGER Page 329 Figure 12 A schematic presentation interpreting the aspect of chamber con- tents as shown in Figures 96 and 97. When the animal was fixed, the shell epithelium had secreted what appears to be an organic mem- brane (om) and one or two gelatinous layers that have not been preserved except where crystallisation of pillar layers (p) had taken place. Between the dorsal shield (ds), in this particular situation (or an organic membrane or a septum, in general) , and the organic membrane (om), the presumably gelatinous contents of the chamber are preserved and exhibit a periodical striation that is particularly distinct in the vicinity of the pillars (cf. Figures 96 and 97) where it appears to match the sequence of “nodular” thickenings. Throughout their growth, only the uppermost portion shows mineral apposition, whereas further towards the base, they do not grow in thickness. These pillars are ran- domly distributed on the chamberceiling, only the foremost ones forming walls that are radially arranged (Figure 75). Pillars are most densely set in the presumptive siphuncular area; they remain columnar in this posterior part of the chamber, whereas more anteriorly situated ones change in form during their growth. The latter measure about 10 jam in diameter; they have transversal bands, and their growth face has a central groove (Figure 77). | In the first chamber of Sepia orbignyana and S. elegans, the pillars are similar to those of S. officinalis. In S. phara- onts, however, the pillar base is often branched. The middle part of these pillars is again columnar (Figure 78). Between these growing pillars, the chamber roof is usu- ally covered by a thin organic sheet; such sheets may also be extended vertically between pillars (Figure 79), so that the first chamber already has a labyrinth-like parti- tion. When the pillars have grown to a length of about 15 to 30 xm, an additional organic sheet is formed; it is extend- ed horizontally between the pillars. When viewed from the ventral side of the shell, such a sheet may cover most of the chamber, except the marginal parts (Figure 76). In the first chamber, 4 to 7 organic sheets may be formed in the central part, in Sepia officinalis as well as in S. phar- aonis (Figure 80). Page 330 Towards their apices (in the direction of growth, 2. e-, towards the ventral end), the pillars change from their initial columnar form to a more wall-like structure. Near the chamber floor, these flattened pillars branch and form crenelations which may come close to those of neighbour- ing pillars. Thus the chamber floor shows a characteristic pattern of meandering lines (Figure 80). The siphuncular zone of the first chamber is a small oval field (Figure 76). It differs from the anterior part of the chamber only by a denser distribution of pillars. The siphuncular area of every following chamber is a crescent- shaped band that shows the characteristic structure known of the cuttlebone (Figure 83). The tendency of the pillars to form wall-like structures increases throughout the growth of the shell, but even in adult specimens, one always finds some columnar pillars within the actual chambers; in the siphuncular area, this remains the typical pillar form in Sepza officinalis, S. or- bignyana and S. elegans. In S. pharaonis, wall-like and columnar pillars may alternate in one and the same meandering row of pillars. The height of the embryonic chambers measures from 0.5 to 0.8mm; this corresponds to the chamber height of juvenile individuals. The first chamber formed after hatching is often markedly lower, however. THE VELIGER Vol. 21; No. 3 The first calcification of the dorsal shell surface appears only after a few chambers are formed, 7. e., around stage XVIII. Aragonite crystallites of about 0.5 wm appear in a random pattern on the surface of the dorsal shield (Fig- ure 37). Prominent sculptural elements, such as radial ridges, wrinkles and growth lines, are covered first. Thus they become very distinct for some time (Figure 45). Later on they will be covered by newly-added aragonitic layers. The crystallites of this initial dorsal cover do not show any particular orientation. They grow along with the for- mation of interspersed organic fibers (Figure 37). Except for the margin of the dorsal shield, the entire dorsal sur- face is rapidly covered by a continuous layer of aragonite crystals; the spherulitic arrangement typical of this dorsal layer is soon established. In Sepia officinalis, the posterior region of the embry- onic dorsal shield is first covered by the same initial layer as the anterior part. The earliest traces of a spine appear only towards the end of embryonic life. The first crystal- lites that build the rudimentary spine are aragonite aggre- gations very similar to those forming the embryonic dorsal layer (Figure 39). The spine forms behind the protoconch grooves that can still be made out through the mineral cover. Explanation of Figures 74 to 85 Figure 74: The embryonic shell of Sepia officinalis before calci- fication shows a central depression in the area of the protoconch. Following the initial shell cap radial sculpture elements and paired grooves situated in the growth lines have been formed when the shell was still free of mineral deposits. First mineral deposits (detail in Figure 45) fix these morphological features x 28 Figure 75: Ventral side of embryonic shell of Sepia officinalis during formation of the first chamber shows the random pattern of the pillar insertion, with exception of the radially arranged fore- most ones that form walls X 42 Figure 76: The central portions of the embryonic shell of Sepia officinalis, towards the end of formation of the second chamber, is covered by a continuous organic sheet of the last intracameral lamella. The siphuncular zone of the first chamber shows up as a small oval field X 30 Figure 77: Pillars in the central portion of the first chamber in Sepia officinalis show a growth face with a central groove. They project over an organic sheet suspended between them and are connected by vertical organic sheets X 730 Figure 78: The pillars of the first chamber of Sepia pharaonis show a branching base turning into a columnar shape. The annu- lations of the pillar are clearly visible X 1 200 Figure 79: Pillars of the first chamber of Sepia pharaonis connect- ed by a vertical organic sheet X 1300 Figure 80: The round and the wall-like pillars of the first chamber of Sepia officinalis are crenelated near their ends in the septum. Organic sheets form 4 floors. The first septum has not yet been secreted X 130 Figure 81: Round pillars at the first chamber of Sepia officinalis branch before they turn into the chamber floor X 370 Figure 82: Fracture through a septum of the chamber zone of Sepia gibba showing the lamellar chamber floor and the prismatic chamber roof with a pillar rooted on it. Organic membranes do not cover the roof or floor surface, but are expanded through the chamber room X 1250 Figure 83: The embryonic shell of Sepia pharaonis during forma- tion of the 6t4 chamber, after which the embryo would normally hatch. In the siphuncular zones of the chambers the organic covers are partly rolled up, exposing the posterior end of the cham- ber (details in Figures 34, 35, 36) XK 12.5 Figure 84: The spine of the hatching Sepia pharaonts is partly covered by organic material. Detail of base in Figure 57 X 620 Figure 85: The spine of Sepia officinalis is composed of lamellar structure which at the spine margins shows a rapid transition into purely organic sheets; these continue across the spine cover into the uncalcified portion of the central layer. For detail see Figure 4! X 19 [BANDEL & BoLerzky] Figures 74 to 85 THE VELIcER, Vol. 21, No. 3 Vol. 21; No. 3 THE VELIGER Page 331 a Imm Figure 13 The cuttlebone of a newly hatched Sepia orbignyana, The rudi- ment of the spine (arrow) is barely visible on the rounded posterior part. A: dorsal view; B: ventro-lateral view It is interesting that the spine is not yet formed in the newly hatched animals of Sepa orbignyana, a species with a very prominent spine in the adult stage. In the youngest animals, one only finds an inconspicuous thicken- ing at the site where the spine will later form (Figure 13). In Sepia pharaonis, the embryonic dorsal layer begins to develop in the form of a series of dispersed crystallisa- tion centers, where aragonite crystals aggregate into com- plete spherulites. These may fuse in the central part of the dorsal shield, whereas near the margins they remain iso- lated (Figures 14, 40). These spherulites consist of needle- like crystallites that radiate from the center of the nodules, which are 12-50jm wide. They are embedded in the organic sheets of the outer and marginal shell layers of the embryonic dorsal shield. In the region of the spine, the shell of embryonic Sepia pharaonis also differs from that of S. officinalis. Towards hatching, S. pharaonis has completed 6 shell chambers (Figure 83); this is less than in hatching S. officinalis, but the spine is already a large and solid structure (Figure 84), whereas in newly hatched S. officinalis it just begins to form. In the spine region of S. pharaonis, the crystal needles show the same orientation within an aggregate; 2. é., there is neither a spherulitic nor a random orienta- tion (Figure 57). These crystallite aggregations tend to Figure 14 Longitudinal section through the cuttlebone of an embryo of Sepia pharaonis (with 5 completed chambers) , showing the spine (s) with lamellar structure, the prismatic dorsal layer (dl) forming spherulitic aggregates near the posterior rim of the shell, and the central layer (cl) that is purely organic in the region of the early embryonic shell and then becomes partly mineralized. In the siphuncular zone (sz) of the second chamber, the space between the pillars is partly filled with aragonitic crystals that show an inorganic type of crystal growth. Page 332 THE VELIGER Voli 215 9Noms Do flatten out, with the needle axes following the plane of the organic sheets next to them (Figure 57). Thus their struc- ture is intermediary between the patterns observed in the dorsal and central layers. respectively. The needle-like crystals of these early spine structures measure 0.2 4m in width, like those of the central layer. The spine of newly hatched §. pharaonis is often covered by organic material ‘Figure 84) ; it strongly resembles the spine of the adult shell, which is similar to that of adult S. orbignyana. During the later embryonic stages, the different parts of the primary shell sac epithelium reflect the increasing complexity of the shell structures they form. APPELLOF Figure 15 Medial longitudinal section of an embryo of Sepia officinalis, at stage XVI of Naef (cf. Figure 10, arrows). A: Semi-schematic presentation of the entire embryo in a medial section. The arrow line B indicates the area enlarged in B. The thick arrows a, b, and c mark parts corresponding to those represented in Figure 16, from (1893) described and figured several typical forms of shell-secreting cells of the adult cuttlefish. DENTON «& GitpIn-Brown (1961) described the micro-anatomy of the siphuncular wall of the shell sac. Finally some ultra- structural aspects of the primary epithelium in the anteri- or chamber zone were described by KawactutTr « ODA (1963). Spiess (1972) tried to relate the histological differen- tiations he observed at stage XVI directly to the different twvpes of cells described by AppELLOFF (1893). With the completion of the first chamber before stage XVI is at- tained, the embryonic cuttlebone has indeed acquired the Tee Don iedeadite COTO erat PEELE TET EPEAT a later stage (abbreviations as in Figure 10). B: Histological aspect of the typical siphuncular epithelium with the early basal infoldings (left part) and of the epithelium of the posterior brim of the shell (sh), the upper right part belonging to the secondary epithelium Vol. 21; No. 3 THE VELIGER Page 333 main elements of the future buoyancy apparatus. How- ever, several parts of the adult cuttlebone, such as the spine, the dorsal layer and the fork, are still lacking. Fur- thermore, a comparison with later embryonic stages shows that the histological differentiation in general is still in its early phase at stage XVI. Thus, c. g., the siphuncular tissue (type D of the 5 cell types listed by Spiess, 1972) only begins to take on its typical structure with the basal infoldings described by DENTON & GitpIn-BRown (1961) (Figures 15B, 16A)}. Also the chamber-forming epitheli- um (type C of Spiess) will attain its adult structure after stage XVI (Figures 16B, 18B). We do not agree, therefore, with Spiess (1972) who states, without presenting any figures of later stages, that “the following stages up to hatching do not present any crucial change in the tissue of the shell complex,” and that rae i Ws Tie Wa : ‘ Riles tHe 8 ! yah tel ER there is only “an insignificant reduction of the height of cells in the primary epithelium.” The contrary is true, as one may see by comparing Figures 11, 15 and 16. What is crucial in these changes is that they lead to structures that are very similar to the histological aspect of the adult tissue. From the figures presented by AppELLGF (1893) and by KawacttTi & Opa (1963) it is clear that the cells forming the calcareous material of the chamber zone are high, columnar cells. The assumption of Spiess (op. cit.: 197) that high cells always form uncalcified structures, whereas calcified structures are always built by cubiform cells, is untenable. The semi-diagrammatic representation of the primary epithelium at stage XVI (Figure 10) shows the periph- eral zone of the high cells that form the organic rim of the dorsal shield (cf. Figure 11B). Next to this peripheral Figure 16 Sagittal sections from an embryo of Sepia officinalis, at stage XVII- XVIII of Naef (for their location cf. Figure 15). Note that these camera lucida drawings are at the same magnification as Figure 15B. A: the typical siphuncular epithelium, with the siphuncu- lar wall of the shell (sh) adhering to it. B: the epithelium that forms the chambers, with high columnar cells and large vacuoles and a broad brush border (bb). The large blood spaces (bs) do not penetrate the epithelium, as they do in the basal infoldings shown in A. C: the extremely flat secondary epithelium (arrows!) Page 334 THE VELIGER Vol. 21; No. 3 a Figure 17 Embryo of Sepia officinalis, at stage XVII of Naef (dorsal view, drawn from living specimen). Note the large outer yolk sac (oys) which will be absorbed by the time of hatching when the animal will have doubled its size (cf. Figure 98). The shell (sh) has two complete chambers, and the third chamber is being formed. The anterior limit of the insertion of the head and funnel retractors can be made out by the position of the stellate ganglia (sg) (cf: Figure 10), which lie behind the collar (c). On the posterior mantle and fin surface lies the anchor-shaped hatching gland (hg) (adjacent column —) zone lies a band of very low cells that secrete the mineral- ized (ventral) marginal zone of the dorsal shield. The actual chamber-forming epithelium, however, is again composed of columnar cells, which are highest in the medio-lateral and anterior parts (Figure 10). The typical siphuncular tissue is rather limited and occupies an oval field close to the posterior end of the shell. This highly vascularized zone is surrounded by an area of apparently the same type of cells that do not form, however, the deeply folded epithelium that is so typical of the central part of the siphuncular zone (cf. Figures 16A and 18C). The growth of the shell complex during the later em- Explanation of Figures 86 to 94 Figure 86: Central pillar zone of Spirula broken open to show the septal neck (base of figure) with its lamellar structure. The pillars (detail Figure 63) are covered with the porous layer consisting of irregular crystals that line the inner space of the siphuncular tube. The lamellar structure of the pillar shows gradation into the irregu- lar structure of the inner cover of the pillar zone X 1700 Figure 87: The collapsed and then solidified end of the siphun- cular tube of Spirula with its organic ribbon that extends to the opposite wall of the initial chamber X 350 Figure 88: At the insertion to the outer wall (right) the septum of Spirula sits on a coarsely prismatic ridge. The septum is com- posed of well differentiated lamellar layers, which end abruptly at the prismatic ridge X 620 Figure 89: The end of the siphuncular tube of Nautilus pompiltus showing the first pillar zone on the nacreous inner wall of the initial shell cap. This pillar zone borders on the chalky layer at the margins of the siphuncular tube. The apical side of the first septum is seen in the lower part of the figure X 95 Figure go: The horny siphuncular tube of Nautilus pompilius ends in the spongy interfusion of the chalky layer and the organic sheets of the tube. This porous zone is in contact with the pillar zone (Figure 91) within the septal neck. A chalky layer is not developed in this particular section of the siphuncular tube X 34 Figure g1: The inner side of the septal neck of Nautilus pompilius opened to demonstrate the inner non-porous ridge (upper portion of figure) covered by the organic sheet that continues into the horny tube (here torn off). The spongy apical end of the horny part of the siphuncular tube rests on the pillar layer seen in the central portion of the figure X 112 Figure g2: A fracture showing the end of the septal neck of the siphuncular tube of Nautilus pompilius. The horny tube and the cover of the chalky layer are seen in the upper part of the figure. In the center is the non-porous ridge forming the attachment of the next section of the siphuncular tube. The tube is torn off near the base of the figure to show the end of the pillar zone X 82 Figure 93: Crystals of the frontal pillar zone of the siphuncular tube of Nautilus show the transition from the lamellar nacreous layers into the prismatic pillars X 1500 Figure 94: The inner pillar zone of the siphuncular tube of Nauti- lus shows the transition from stacks of nacre platelets to pillars of prismatic structure X 2950 [BANDEL & BoLerzKy] Figures 86 to 94 Tue VE.icER, Vol. 21, No. 3 Vol. 21; No. 3 THE VELIGER Page 335 bryonic stages is most intensive in the anterior part of the mantle (cf. Figures 10 and 17), so that the insertion of the large head and funnel retractors continually ap- proaches its definitive extent in the posterior part of the shell, on either side of the siphuncular zone (cf. Tomp- SETT, 1939, for the anatomy of the muscular and other systems of the adult cuttlefish). The secondary shell epithelium that forms the dorsal layer of the dorsal shield from stage XVIII onward re- mains very flat (Figure 16C). At its periphery, it becomes gradually thicker before it turns into the marginal part of the primary epithelium. In this outermost marginal area, the cuttlebone is firmly attached to the shell epithelium, which in turn is fixed via a delicate cartilaginous band to the dorso-lateral margin of the muscular mantle (Figures 10, 11B). The lateral pockets at the base of the fins (Fig- ure 10) are gradually separated from the secondary epi- thelium. When the animals hatch, their general aspect is very similar to that of the adult animal. However, the body proportions still differ markedly from those of the adult. This is also true for the proportions of the shell; its width to length ratio is about 1:2 at hatching, against something like 3:8 at the adult age. Also the relative length of the last septum, which in young animals is shorter than the siphuncular zone, will increase during later development (Mancoip, 1966). Only under artificial starving condi- tions will the last chamber always be shorter than the si- phuncular zone; except for extreme starvation leading to constant positive buoyancy of the animal, these abnormal proportions of the chamber zone do not influence the buoyancy mechanism of the animal (BoLETzky, 19742). We are still far from a detailed knowledge of the func- tion at the cellular level of the different parts of the epi- thelium that surrounds the cuttlebone, builds its complex structures and forms the physical and physiological link between the other living tissues and the shell. In order to elucidate all the biological processes going on in the shell complex, a very detailed histochemical and ultrastructural study of the shell sac epithelium will have to be carried out on material that must be obtained under various well-defined experimental conditions. 1ounm Figure 18 Sections from a juvenile Sepia officinalis,a few weeks after hatching. A: Cross section close to the anterior end of the cuttlebone. The left part of the shell (sh) is the organic rim (uniformly stippled). The middle part next to this shows artificial cavities due to the dis- solution of calcareous shell material during fixation. At right is the peripheral part of the chamber zone, enlarged in B (cf. Figure 16B). C: Cross section from the lateral part of the siphuncular zone in the same specimen. In contrast to the central part of the siphuncular zone, the epithelium is rather flat and shows no basal infoldings. It adheres to the organic membrane (om) forming the bottom of the chamber (ch) in the siphuncular zone. The small chamber height indicated by the next upper septum (s) shows that this section passes through the rearmost part of the chamber. Page 336 THE VELIGER Vol. 21; No. 3 Development of the Shell Complex in Spzrula The embryonic development of Spirula is still unknown. It is also uncertain whether the smallest animals caught with plankton nets are newly hatched young. However, NaeF (1923, 1928) estimated from the size of mature ovarian eggs as indicated by CHUN (1910), that the newly hatched animals might have a total length of about 4mm and that their shell would then have not more than 2 or 3 completed chambers. In the Sepioidea so far studied, the dorsal mantle length of newly hatched animals corresponds roughly to the length of the mature ovarian egg from which they have developed. In Spirula, mature ovarian eggs measure 1.7 mm according to CHUN (1910). The smallest specimens we have been able to study, thanks to the kindness of Prof. Dr. E. J. Denton (cf. DENTON & Gi_prn-BRowN, 1971), had a dorsal mantle length of about 2.7mm, and their shell already had 3 complete (closed) chambers. The smallest specimens observed by CLaRKE (1970) had a mantle length of only about 2mm; probably they had not more than 2 closed chambers. If the newly hatched ani- mals are markedly smaller, with a mantle-length of about 1.7mm, it seems likely that they have only the first cham- ber closed, which measures 0.7mm. Since in the known specimens the closed part of the shell never takes up more than half of the mantle length, one can practically exclude the possibility that the mantle complex that is markedly shorter than 2mm holds a shell with 2 closed chambers. As only the posterior part of the digestive gland (“liver”) occupies the open chamber (“living chamber’), the ante- rior part has to find its place in front of the shell, inside the mantle. In the smallest specimens we have seen, the posterior part of the head with the statocysts is also re- tracted into the mantle cavity, as in the adult. It seems reasonable, therefore, to assume that Spirula hatches with the first chamber of the shell completed (and probably containing some gas to give the animal neutral buoyancy) — possibly with the second chamber com- pleted, if the mantle-length of the newly hatched animal is not less than 2mm (cf. Figure 19B). Jousin (1910) and Nagr (1928) have clearly shown that the hypothesis of HuxLry & PELSENEER (1895) pos- tulating a partly external formation of the early shell in Spirula is untenable. Certainly the embryonic shell of Spirula is formed inside a closed shell sac that is more cup-shaped, however, than it is in other decapods. The early hypothetical stages figured in JousIN (op. cit.: figs. 15, 16) are not actually convincing, since the shell rudi- ment there appears as a narrow “pen” in the dorsal ante- rior part of the mantle, similar to the rudimentary shell of sepiolids. The following stage, however (stage III of Figure 19 Hypothetical developmental stages of Spirula, after JouBIN (1910, figs. 17 and 18). A: stage III of Joubin, with formation of the first chamber. At this stage, the embryo would have a large outer yolk sac. B: stage IV of Joubin, with formation of the second chamber. Arrows indicate the plane of insertion of the mantle muscle on the shell complex JouBIn, op. cit.: fig. 17) is likely to come close to reality. We have redrawn it in our Figure 19A. NAEF (op. cit.) suggested that in the early embryonic shell complex of Spirula, there should be some rudimentary formation rep- resenting the proostracum, which would disappear during later embryonic development. At any rate, the initial chamber does not show any trace of an early proostracum rudiment (which might simply be represented by the primary insertion of the dorsal part of the mantle rudi- ment on the margin of the shell sac). What is important is that the insertion of the mantle muscle apparently “moves” from its primary location on the edge of the shell sac (where it probably lies at early organogenetic stages) to the outer surface of the shell sac, so that the first chamber can take up its position inside the muscular mantle. This displacement of the muscle in- sertion probably starts on the ventral side, but it also at- tains the dorsal side of the shell sac, the foremost part of which will then always lie under the muscle insertion. A comparison of Figures 19A and 19B may help to under- stand this process. Figure 19B (stage IV of Jousin, 1910) would represent a stage near hatching, according to our estimation of size and shell development. With the further growth of the coiled shell, the dis- placement of the muscle insertion on the lateral and ven- tral parts of the shell complex continues, and early in Nolet 2-0 No. 13 juvenile life the part of the shell sac that contains the first chambers becomes entirely detached from the mantle. The “movement” of the growing shell in relation to the mantle can best be compared to the movement of the in- nermost part of a spring in a clock-work that is being wound up. The faster addition of shell material on the dorsal side of the shell as compared to the ventral side, which gener- ates the spiral growth, seems to begin right after the for- mation of the protoconch; the posterior attachment of the “prosiphon” presumably lies in the protoconch area, and this attachment in fact lies on the ventral side rather than opposite the aperture (Figures 20, 64). As we stated earlier, in the first chamber of the Spirula shell, the entire surface of the siphuncular tube is covered by a wrinkled organic sheet, from the aperture of the chamber to the line along which the “prosiphon” is at- tached to the wall (Figure 5). This organic sheet is the original embryonic siphuncular tube of the first chamber. Its formation and the subsequent modifications can be imagined to take the following course. Before the siphuncle forms, the aperture of the first chamber is further constricted by a ring-shaped ridge that is secreted on the inner surface of the apertural constric- tion {Figure 204). The formation of the second chamber has begun. As DENTON & GILPIN-BRowN (1971) have shown that only a small part of the new chamber wall is formed when the third chamber is closed, one can assume a similar situation for the closure of the first chamber. Then the epithelium that has formed the prismatic wall of the first chamber separates from this wall, except for a line of attachment in the presumed protoconch area. It then secretes the organic sheet forming the first embryonic siphuncular tube while it is slowly retracted, the first chamber becoming filled with liquid (Figure 20B). The next step is the formation of a calcareous tube that is wider near the apertural side than at its posterior end. The tissue of the siphuncle by then is well differentiated. The elastic organic tube, from which the tissue is now be- ing removed, is apparently twisted near its (apertural) base before the calcareous tube is formed. The latter fixes the radial wrinkles resulting from this twisting movement, the significance of which is obscure (it reminds one of the hypothesis proposed by Kerr, 1931, according to which the endogastric coiling of the Spirula shell had been brought about by the rotation of an originally exo- gastric coil, in some remote ancestor. This hypothesis appears rather imaginative). The organic cap that closes the siphuncular tube is not sustained so that it may collapse (Figure 87). It either forms an edge on the end of the calcareous tube, or it re- inGay EEIGER Page 337 Figure 20 A schematic presentation of the processes by which the tissue with- draws from the first chamber of the embryonic Spirula shell. A: the aperture of the first chamber is further constricted by a ring-shaped ridge. B: the epithelium that has formed the pris- matic wall of the first chamber separates from the wall, except for the linear attachment in the (presumed) protoconch area. C: the calcareous tube forms after the siphuncular tissue has withdrawn from the elastic organic tube tains its rounded cap-shape (Figures 20C, 64). This is fixed before liquid is extracted from the first chamber, which then becomes part of the functional buoyancy apparatus. Development of the Shell Structures in Sepia and Spirula The mineral composition of the shell of Sepia and Spirula is essentially the same. In both forms, aragonitic crystal- lites compose 3 types of layers: 1. the irregular structure made of aragonite crystals and crystal aggregations; 2. the regularly constructed prismatic layer; 3. the more complex lamellar layer. Type 3 forms the major part of the shell wall in Spirula, the whole septum and the anterior part of the siphuncular Page 338 tube. The pillars of the posterior part of the siphuncular tube of Spzrula also show the lamellar structure, like those supporting the chamber septum of Sepia. In the latter, the calcified parts of the central layer including the spine, of the fork layer, and the septa of the chamber zone have a lamellar structure. Type 2 is found in the inner layer of Sepia and, as a more regular type consisting of coarse needle crystals, in the inner shell wall of Spirula. Still coarser crystals are found in the constriction that forms in the inner shell wall of Spirula, before insertion of a new septum takes place. Irregular, coarse crystals in spherulitic prismatic orienta- tion (type 1 - 2) compose the outer secondary layer of the Spirula shell, the dorsal laver of the cuttlebone of Sepia, and the crystalline covers that appear late in the ontogen- esis of Sepia in the posterior part of the siphuncular zone. The last-formed sheets of the inner layer of Sepia show a structure of spherulitic-sector and are composed of thin crystal needles. In fractures made parallel to the sector axis, they have a feather-like appearance. Type 1 forms the cover of the siphuncular pillars of Spirula, and the crystalline filling of the posterior-most part of each chamber in the siphuncular zone of Sepia. The simplest form of aragonitic shell structure is repre- sented by the crystal aggregations and the single crystals that form a loosely interlocking porous layer. The crystals of the early dorsal layer in Sepza officinalis and of the si- phuncular deposits in Sepia and Spirula have this struc- ture. They are the product of an undisturbed crystal growth from liquids or mucus rich in calcium carbonate, where the shell secreting epithelium does not influence crystallisation. Such crystals are known from many ara- gonitic mollusc shells where crystals grow very rapidly; for example, during formation of a first layer of shell septa in the apertural whorls of gastropods (BANDEL, 1975), or closure of other cavities in gastropod and bivalve shells THE VELIGER Vol. 21; No. 3 (BANDEL « HEMLEBEN, 1975), and also within cavities closed off from the living tissue after the animal has with- drawn from them and formed a septum. Without any contact with the living tissue, remaining liquid or mucus rich in calcium-carbonate may then form crystals of the same shape and size as crystals that occur in mucus or body liquid still in contact with the secreting epithelium. The crystals and crystal aggregations of the porous layers formed in Sepia and Spirula can, therefore, be considered as largely uncontrolled formation of aragonite with the in- organic type of growth (BANDEL & HEMLEBEN, op. cit.; BaNDEL, 1977a). They are not to be considered as bio- crystals in the strict sense of the term (2. e., structures of higher organisation where crystals are not “allowed” to form in their typical crystallographic shape, with well-de- veloped crystal faces). Such an indirect pathway of crystallisation without contact with the shell-secreting epithelium must be taken by the aggregates and crystals that lie between the pillars of the posterior pillar zone in Sepza and in Spirula. In the latter there are drum-shaped, short pillars; in Sepza they are thinner, more columnar. In both forms, these pillars show the lamellar type of construction, which is of much higher organisation than the inorganic type represented by the crystals and crystal aggregations that lie between the pillars. In this siphuncular zone, the completed pil- Jars are covered by organic sheets; these apparently are permeable to liquid loaded with calcium carbonate that is secreted by the siphuncular epithelium. Crystals and crystal aggregations of inorganic fabric may also grade into the 2 types of higher structure pres- ent in the shells of Sepia and Spirula. In Spirula, the pil- lars of the siphuncular zone (posterior part of the tube) that are made of lamellae show a gradation into the ir- regular porous laver, via a transitional zone. The small, rod-like crystals of the pillar lamellae grow in thickness and become continuous across lamellae. Thus large crys- Explanation of Figures 95 to 99 Figure 95: Dorsal view of the mantle of a Sepia officinalis embryo at stage XIII - XIV (fixed specimen). The dorsal part of the shell sac and the thin organic shell (cf. Figure 8) are removed. to expose the primary epithelium. The arrow points to the longitudinal groove Figures 96 and 97: Cross sections of the embryonic shell of Sepia officinalis at stage NVI of Naef (interference phase contrast photo- graph of histological section of material fixed in Bouin’s solution). These sections are of the anterior part of the shell where the second chamber which is being formed lies under the dorsal shield (ds). The cavity of the chamber (ch) is filled with the future chamber liquid that appears still to be in a gelatinous state, exhibiting peri- odical striation that matches the annulations of the pillars (p). (Note: the closed first chamber, not shown by these sections, does not present this striation between the pillars, probably because the chamber contents are already liquefied) Figures 98 and 99: Newly hatched Sepia officinalis; anaesthetized live specimen. The skin of the mantle has been removed to show the shell complex, with the gas spaces of the cuttlebone showing up with a dark outline in transmitted light (Figure 98; co = collar, sg = stellate ganglion) and as bright reflecting surfaces in incident light (Figure 99) Tue VE.icER, Vol. 21, No. 3 [BanDEL & BoLteTzky] Figures 95 to 9g Vol. 21; No. 3 tallites form in which lamellationis still visible at some dis- tance until it disappears entirely. The crystals then show well-developed faces. The irregular layer following the highly regular pillar layer consists of crystals and crystal aggregates that are interwoven with organic fibers and sheets. As there is no alternation of crystalline material and organic sheets, the organic material must have poly- merized in the interstices left between the crystals. It therefore seems likely that the organic shell material of these layers differs in composition and fabric from the organic sheets that are suspended between pillars, reflect- ing the different degree of complexity in their mode of formation. The layer of irregular crystals and crystal aggregates resembles very much the first layers produced in the shell apex of certain marine gastropods, when a cavity is closed off by a septum (BANDEL, 1975: plt. 2, fig. 5). A continu- ous transition from lamellar layers (nacreous structure in this particular case) to crystal aggregates of inorganic fabric was found in the hollow spines of 2 archaeogastro- pod species (BANDEL, 1977a). In these cavities, pillar- or pyramid-shaped stacks of nacreous plates grade into crystal aggregations with a radiating structure. Similar transitions exist in the Nautilus shell (MUTVEI, 1972; cf. our Figures 93, 94). The first irregular crystal cover, by which the forma- tion of the dorsal layer in Sepza officinalis begins, also re- sembles the cover of crystal deposits in the shell repair of gastropods (BANDEL & HEMLEBEN, 1975). As in some gastropod septa, this layer grows into a prismatic or spherulitic prismatic structure with needle-like crystals of variable thickness that are oriented vertically to the growth face (cf. BANDEL, 1975: plt. 5, fig. 5; BANDEL & HEMLEBEN, op. cit.: figs. 2, 4, 11). The dorsal layer of the Sepia and Spirula shell is made of crystal needles of different sizes; they either form a coarse prismatic layer, or spherulitic-prismatic ridges and bumps. The latter often show a radial arrangement of the needle crystals around the central base, in a spherulitic manner. The dorsal layer grows by mere enlargement of the needle crystals that show well-developed crystal faces. This kind of growth does not require much interaction with the shell-secreting epithelium. The latter creates a chemical micro-environment that favours the formation of aragonite and the final production of an organic cover to end the crystal growth. The inner prismatic layer of the Spirula shell and the inner layer of the cuttlebone of Sepia show a spherulitic prismatic structure with a more regular arrangement of crystals than in the dorsal layer. But the influence of the epithelium on the mineral structure is still limited; crys- tals are large and show well-developed crystal faces. In THE VELIGER Page 339 the lower part of the inner layer of Sepia, the width of crystals is smaller, and the spherulitic sectors they compose are more apparent than in the upper part where crystal- lites are broader. The needle crystals that grow on the inner surface in round bump-like structures are inclined towards a common central axis, thus forming columnar units. The single needles are crystals with well-developed heads at the growth face. In contrast to the structures so far discussed, with crys- tals that may attain considerable size and that show crystal faces, the lamellar layer is composed of small elements (0.1 to 0.3 4m) that rarely show crystal faces. These elements are surrounded by and interlocked with organic shell material to a much greater extent than crys- tals are in other structures. These smallest units may be arranged in many different ways, but they always form a lamellar structure with lamellae strictly parallel to the growth surface. The thickness of lamellae varies from 0.1 to 15 4m. Lamellae are continuous over large stretches; we have rarely found a free end or a splitting. However, mineralized lamellae may turn abruptly into lamellar organic sheets. At the interface with one of the 2 other types of structure observed in Spirula and Sepia, lamella- tion sometimes continues a little into the other layer. MutveE! (1970, 1972a, 1972b) described the nacreous layer of Nautilus and Mytilus as being composed of small crystalline units that are very similar to those we find in the lamellar layer. The typical nacreous crystals are tab- ular and have a hexagonal outline; they are known from many species of gastropods, lamellibranchs and cephalo- pods (Recent Nautilus, fossil Nautiloids and Ammonoids). BaNDEL (19774) has shown that the smallest components of mature nacre are round or irregular rod-like elements, particularly visible on the sides of growing platelets. These smallest elements (0.2 um) build platelets that have the optical properties of monocrystals. The nacre platelets described by Mutver (1972a) from the septum and the siphuncular tube of Nautilus have a highly variable intra- crystalline structure. Variation is particularly great in the posterior end of the calcified septal neck, with platelets made of needles 0.1 - 0.2 4m in thickness, of dendritic crystallites or rods (MuTVEI, 1972a: plts. 15, 16). As in the lamellar layer, these crystallites are composed of smaller granules with a maximum diameter of 0.2 - 0.3 pum. But in contrast to the lamellar layer, these crystal laths build platelets with distinct margins. It is conceiv- able that the lamellar layer is a structure derived from nacre platelets of the type described by Mutvei from the posterior siphuncular tube of Nautilus. Similar to what has been shown by Mutver (1970, 1972a, 1972b) and BanpDeEL (1977a) for nacre platelets, the lamellae of the lamellar layer may be composed of Page 340 needle elements lying parallel to each other, of dendritic crystallites with bifurcating branches, of rods parallel and perpendicular to the plane of lamellation, and of very small, irregular units. All components show the same basal unit with a size between 0.1 and 0.3 wm (as in dif- ferent aragonitic layers of certain mollusc shells with crossed lamellae or with a helical structure; cf. BANDEL, 19776). In the hollow spines of the archaeogastropods Guild- fordia and Angaria, BANDEL (1977a) found columnar nacreous structures that extend parallel into the central space of the spine. At their base, these pillars show mature nacre, followed by an increasingly coarse composition in subsequent platelets. In their uppermost part, the pillars are composed of coarse aragonite crystals. Lamellation continues through neighbouring pillars, and the lamellae are strictly parallel to each other. During their growth, the pillars are surrounded by liquids that are rich in cal- cium carbonate, and each nacre lamella continues to en- large only according to its own structure, independently of the neighbouring lamellae. The closure of narrow spaces in the vicinity of these columnar structures during further growth is no evidence of the presence of membranes that should surround each lamella, thus restricting its type of growth to one specific structure, as postulated by the “compartment theory” (see ERBEN, 1974, and BaNDEL, 1977a for a discussion of the two main hypotheses on the mode of shell formation in the molluscs). In an attempt to explain the difference in the respective type of crystal growth in the nacre of these pillars, from mature nacre to large crystals of inorganic fabric, BANDEL (op. cit.) suggested that lamellae of gelatinous matter, successively secreted by the epithelium, may form the medium in which the nacre platelets form. The chemical composition and the consistency of these gelatinous layers were thought to determine the composition and structure of the forming platelet. Since the gelatinous lamellae may liquefy or be precip- itated on the mineral shell components, they are generally not preserved by current fixation methods. However, our observations on the lamellar filling of newly formed cham- ber sections in the Sepza shell confirm the hypothesis of BANDEL (19774) on the mode of formation of the lamellar structure in nacreous layers. It must be emphasised, however, that the “chitinous” material which APPELLOF (1893) observed in the last- formed chamber of cuttlebones is most likely the product of precipitation of the chamber liquid, rather than gelat- inous layers not yet liquefied. These probably are liquefied in the upper layers of a chamber, separated to a large extent from the lower parts in formation by the horizon- tal organic sheets; so that only lower parts contain con- sistent gelatinous layers when the chamber floor is formed. THE VELIGER Vol. 21; No. 3 In the last-formed chamber of alcohol-preserved cuttle- bones, we have indeed observed contents that recall Ap- pellof’s description. Homology of the Shell Constituents in Sepia and Spirula ApPELLOF (1893) apparently realized that the entire chamber zone of the cuttlebone should be considered as homologous to the siphuncular tube of Spirula and Nauti- lus, as the chambers of both have pillars at, or close to, the inner side of the septal neck (we shall return to his observations on Nautilus further below). In Sepia, the chamber zone, together with the fork, would represent a greatly modified siphuncular tube with an extremely en- larged dorsal part (==chamber zone) and an almost completely reduced ventral part (= fork). We have shown above that neither the number of fork layers nor the total number of lamellae that make up these layers correspond to the number of chambers. According to Appelléf’s idea of the development of the Sepza shell, earlier forms like Belosepia of the Eocene would have been followed by forms with flatter and broader shells, until the ventral part became completely “compressed” in the posterior portion of the cuttlebone in Sepia. NaF (1922) also considered Belose pia as a transitional form in the evolution of the Sepia shell. He suggested that the outer wall of the phragmocone (“Conothek”’) took its part in the formation of the fork. In Naef’s re- construction, the septal necks become flatter and the si- phuncular tube widens until it is a shallow pit. The pro- ostracum, still present in his reconstruction of Belosepia, disappears. According to Naef, Belosepia is derived from ancestors like Spirulirostra and Belemnosella, which had a proostracum and phragmocones that were longer than in Belose pia. We have been able, thanks to the kindness of Dr. L. Jansen (Leiden), to examine a well preserved Miocene representative of Spirulirostra. This fossil form closely re- sembles Spirula, except for the large rostrum. We have not seen any particular similarity to Sepia. Although the gross morphology of the siphuncular tube of Spzrula is very dif ferent from the siphuncular zone of Sepia, it has been shown by DENTON & GILPIN-BROWN (1971, 1973) that in both forms the siphuncular complexes are alike. The shell wall and the septa are always impermeable to sea water and other aqueous solutions; the only permeable zones lie in the siphuncular tube of the S'‘pzrula shell and in the siphuncular zone of the cuttlebone. In Spzrula, the permeable zone is restricted to the posterior part of the siphuncular tube, and in the cuttlebone it is restricted to the rearmost part of what we call chamber in the Sepza Vol. 21; No. 3 shell. Thus the only connection between the liquid inside a chamber and the living tissue of the siphuncle is through the permeable organic membranes of these specialized zones of the siphuncular wall. From a newly closed chamber the liquid is actively extracted while gases slowly diffuse into the chamber; this exchange is prepared by the removal of salt from the chamber liquid (DENTON & GiLpIn-BRowN, 1966). When gas appears in a new chamber of Spirula, the salt concentration of the remaining chamber liquid is only 4 of that in the blood and sea water (DENTON & GILPIN- Brown, 19714). This osmotic difference that is actively maintained by the siphuncular tissue counteracts the hy- drostatic pressure; the volume of the gas spaces can thus remain nearly constant despite an increasing outer pres- sure when the animal descends into deeper water, the salt concentration of the chamber liquid being lowered with increasing hydrostatic pressure. With the appearance of a gas bubble in a newly closed chamber, the main volume of chamber liquid is “de- coupled” from the liquid that is in contact with the si- phuncular wall, so that short-lasting changes in hydro- static pressure do not imply an adjustment of the salt concentration in the entire chamber liquid (DENTON et al., 1961). Spirula normally swims head down, and in this position the main volume of chamber liquid is de-coupled from the permeable region as shown by DENTON et al. (1971). These authors cite a personal communication of Clarke, who had observed that Spzrula can reverse this position for some time, and conclude: “Thus in Spirula the main body of liquid within a recently formed chamber may sometimes be brought directly against the permeable region of the siphuncular tube. It remains true, however, that when Spirula is in its normal swimming position, this liquid will be almost completely de-coupled from the per- meable region.” This problem of course does not arise with the cuttle- bone of Sepia where the main body of liquid is distributed in the form of a fluid film covering the greatly enlarged inner surface of the chamber into which gas has diffused. And even in the newly formed chamber, “the exchange of salts between the liquid just inside the siphuncular sur- face and that deeper within the cuttlebone will be limited by diffusion” (DENTON et al., 1961). Neutral buoyancy is thus achieved in the pelagic Spiru- la and in the nekto-benthic Sepia by a regulatory mechan- ism the structural elements of which are very similar despite the different shell form. Although we have no direct evidence of a common ancestor of Sepia and Spiru- la, there can be little doubt of the homology of these structural elements that compose the permeable siphun- THE VELIGER Page 341 cular wall and the “de-coupling” zone. In the Sepia shell, this zone with its pillars and organic sheets has completely “replaced” the actual chamber of the form that is rep- resented by the Spirula shell. SURVEY or tHE SIPHUNCULAR SYSTEM oF ECTOCOCHLEATE CEPHALOPODS AND OF THE BELEMNITES In a series of studies, DENTON & GILPIN-BROWN and DenTOoN et al. (see DENTON, 1974 for complete list of references) have analysed the structure and functioning of the buoyancy apparatus of Nautilus, Spirula and Sepia, and they suggest that the mechanism by which liquid is pumped out of a newly formed chamber and gas diffuses into it must have been the same in all cephalopods with chambered shells, including the fossil nautiloids, ammono- ids and belemnites. Nautiloidea In Nautilus, the chalky and probably also the horny parts of the siphuncular tube are porous. The respective volume of chamber liquid diminishes from the last chamber to the older ones, most of the chambers containing very little liquid (DENTON & GiLPInN-BRown, 1966). The complete extraction of liquid from a chamber in Nautilus depends on the physical properties of the pellicle that lines the chamber and the siphuncular tube. This pellicle makes the walls wettable, and the chalky siphun- cular tube acts as a wick that draws liquid uphill towards the siphuncular epithelium (DENTON & GrLPIN-BRowNn, 1966). The chalky siphuncular tube (spherulitic-pris- matic layer of MuTVEI, 1972a), in addition to acting as a wick also serves as a small reservoir of liquid close to the siphuncular epithelium. An additional space for liquid lies between the pillar-like structures, which are set on the nacreous central surface of the concave septal face and are covered by an organic pellicle. This pillar zone ex- tends a little into the septal neck and there comes into contact with the porous chalky layer. The structure of the siphuncular tube of Nautilus has been described in some detail by ApPpELLOF (1893). He found that the nacreous septal neck is continuous with the horny tube. The latter is covered on the chamber side by a porous calcareous layer, the “chalky layer” of DENTON & Gitpin-Brown (1966). Where this compound tube en- ters the aperture of the next older septum, it makes con- tact with a crystal structure in the form of pillars that are clearly separated by interstices. Appelléf also noted that only on the inner side of the apical-most portion of the Page 342 THE VELIGER Vol. 21; No. 3 septal neck a solid (non-porous) calcareous inner layer is formed, in which this section of the siphuncular tube ends. Mutve! (1972a) studied the siphuncular tube of Nau- tilus again in great detail. He showed that the single or- ganic sheets that compose the horny tube are calcified close to their apical end, 7. e., inside the septal neck of the next older septum. Thus they are solidly fused with the inner side of this septal neck. Our observation on the siphuncular tube of Nautilus pompilius Linnaeus, 1758 indicate that the horny tube splits ito thin organic sheets before it reaches the non- porous calcareous ridge mentioned above. These obser- vations differ from those of Mutve1 (19722: fig. 2), who figures the horny tube without a change in its structure up to the solid inner ridge. Only in contact with this ridge the horny tube is shown to split into single sheets that are incorporated in the ridge. A reconstruction similar to that of Mutvei has been presented by Buinp (1976: figs. 5, 7)- Longitudinal section of the siphuncular tube of Nautilus pompilius. The arrow points toward the aperture. The nacreous layers of the septum (s) continue into the septal neck (sn), the organic parts of which are continuous with the horny tube (ht). The septal neck and the horny tube are covered by the chalky layer (cl) which is a porous structure made of needle aggregates and organic sheets. The 2 Our Figure 21 shows the attachment of the siphuncular tube within the septal neck of the previously formed sep- tum, with the horny siphuncular tube splitting into many sheet-like, discontinuous and irregularorganic membranes before it ends in the solid inner ridge. In this part, the or- ganic tube is interspersed with the irregular prismatic crystals that are present all through the chalky layer of the siphuncular tube; it has a spongy structure therefore (Figure go). This structure is very likely more permeable to liquids than the actual horny tube, which is rather solid (Figure 22). In the pillar zone inside the septal neck, the pillars are widely spaced (Figure 94). This zone is in contact with the spongy end of the siphuncular tube belonging to the following chamber. So we find an ar- rangement of pillars and an irregular roof made of crys- tal aggregates and organic sheets very similar to what we have seen in Spirula. The porous area is much shorter than in Spirula, however. Behind this spongy part, the organic sheets unite again, partly covering and partly penetrating the solid ridge x? apical end of each section of the siphuncular tube is firmly attached to the inner side of the septal neck by a solid inner ridge (ir). In front of this lies a porous spongy structure (ss) made of many discontinuous organic membranes interspersed with elements of the chalky layer. This spongy structure brings the liquid contained in the pillar zone (pz) into contact with the siphuncular tissue Vol. 21; No. 3 THE VELIGER Page 343 WNNINTUUE| A AMHHE ZaeAy Wt iy yan ae si WIZE Ty \" eo ( ges Zoe TTR aa ‘\ \ \3) SNA ne Vi iy YY Figure 22 Section through the beginning of the siphuncular tube of Nautilus pompilius. The siphuncle makes contact with the inner side of the shell at the site of the earliest embryonic shell (protoconch). Be- tween the nacre of the shell wall and the blind end of the siphuncu- lar tube lies a porous, prismatic first pillar zone (15t pz). In the central part, this zone is covered by an organic layer (ol), and in the peripheral parts by a chalky layer (cl) made of organic sheets and prismatic crystallites. The nacreous septal neck (sn) extends to the porous first pillar zone, through which the liquid of the first chamber is pumped out before more shell material is deposited with the formation of the following section of the siphuncular tube. The latter forms a solid prismatic cap (pc) closing the porous end of the siphuncular tube. The second pillar zone (2"4 pz) corresponds to what is formed in later parts of the tube (Figures 21; 91, 92). DENTON & GiLpIN-Brown (1966) showed that the siphuncular tube of living Nautilus is porous. Their experiments were carried out in such a way that more or less porous zones would not be differenti- ated along the tube. The structure of the siphuncular tube now Clearly shows that the most porous zone lies at the apical end of each tube section. There the liquid that is in close contact with the siphuncular tissue is retained in the interstices between the pillars; thus it is de-coupled from the main body of chamber liquid. The beginning of the siphuncular tube is shown in Figures 22 and 89. Different reconstructions of this feature have been presented in the literature. Mutve1 (1964, text fig. 26; plt. 14) has found an outer spherulitic-prismatic = layer corresponding to the outer chalky layer of the si- = phuncular tube of later chambers. In his reconstruction, a continuous nacreous layer, which is thin in the earliest part of the siphuncle, underlies the outer chalky layer. ERBEN, FLajs & SIEHL (19609: fig. 8; plt. 11, figs. 4, 5) reconstructed the blind beginning of the siphuncular tube as consisting of an outer organic layer and a solid, con- tinuous nacreous wall beneath it. In the explanation of their figure 1 on plate 13, however, they note that the api- cal portion of this nacreous layer is very rich in organic material. BLIND (1976) found that the outermost hull of the initial cap of the siphuncular tube consists of irregular crystalline elements and of organic sheets, thus confirming both the observations of Mutvei and those of Erben, Flajs and Sieh]. Blind stated that the nacreous layer that makes up the apical cap of the siphuncular tube seems to have a prismatic structure. In his figure 3 the wall of the cap is presented as a solid structure that would be impermeable to liquids. Since the first chamber of Nautilus pompilius has been shown to contain gas, this chamber must have been pumped out through the initial part of the siphuncular tube. This seems difficult with a structure as represented by the reconstructions of MutTver (1964: text fig. 29), ERBEN, FLajs & SIEHL (1969: fig. 8) and BLIND (1976: fig. 3). They all show a solidly calcified initial cap the layers of which are continuous with the nacre of the septum. This agrees with Appellof’s assumption that the initial siphuncular tube is solidly mineralized. However, the layers seen in the cap-like beginning of the siphuncular tube have not all been deposited one immediately after the other; they belong to 2 different phases of secretion (cf. Figure 22). In the first phase, crys- tal growth starts with the formation of pillar-like crystal- lites on the nacreous inner wall of the shell apex. Then irregular crystals and sheet-like, discontinuous organic membranes form the chalky layer on the sides of the si- phuncle that is now differentiated (Figure 89). Only next to the shell wall purely organic sheets are formed; they cover the porous prismatic layer of the first pillar zone. At the apical margins, growth of irregular crystals and deposition of organic sheets continue when the nacre- ous septal neck and the septum grow. Thus, the short initial siphuncular tube is very similar to the sections formed later on, with the only exception that the actual horny tube is missing and the nacreous neck is followed by the spongy complex of organic sheets and irregular, loosely packed crystallites. In contrast to later portions, the ending of the organic tube is fused to form the initial cap. Page 344 At the end of nacre growth, the first siphuncular tube is functional, and the liquid of the first chamber can be pumped out. When the second chamber forms, a loosely prismatic layer (pillar zone) grows on the sides of the first siphuncular tube, and the new section of the siphun- cular tube is fused into the old blind portion. Then a solid calcareous ring forms near the apex of the siphun- cular tube. This ring fuses at its apical side and thus be- comes a solid prismatic cap that seals the first chamber. In this newly formed, impermeable prismatic cap, the organic layers of the new section of the siphuncular tube are firmly attached. In all other features this second sec- tion of the siphuncular tube is like those formed later on. A pillar zone serving as a fluid reservoir did not exist in the siphuncular system of Pseudorthoceras from the Carboniferous period (MutvE!, 19724). A spherulitic- prismatic layer (chalky layer) near the septal neck was absent in this form and the prismatic layer on the inner side of the foremost part of the septal neck is solid; there are no pillars or pores. The organic posterior part of the siphuncular tube contains some needle aggregates; it must have been permeable for gas and liquid (MuTvEI, 1972C). As far as we know to date, little space was available in Pseudorthoceras for liquids that were not in direct contact with the main body of chamber liquid. This situation would have impeded an extensive vertical mobility. DenTON (1974: plt. 17) figures the siphuncular tube of the endoceratoid Dideroceras. In this animal, the cal- careous portion of the siphuncular tube extends into the siphuncular tube formed before, passing halfway through the next older chamber. The permeable part would be confined to the small region lying between the septal neck and the calcareous tube, very much as in the Recent Spirula. It is not known whether there were any pillar structures or organic portions as a continuation of the calcareous siphuncular tube, as there are no traces of such formations in this fossil form. But this form shows that among orthocone cephalopods from Paleozoic times, siphuncular structures different from the situation known in Pseudorthoceras have existed, which resemble those of the Recent Sprrula. Ammonoidea According to LEHMANN (1976), MuTvet (1967), ERBEN, FLAJsS & SIEHL (1969), ERBEN & Rew (1971) and Brxe- LUND & Hansen (1968) the siphuncular tube of the ammonoids has a strueture similar to that of Pseudortho- ceras. Again there is no chalky porous layer, and the poste- rior part of the siphuncular tube is organic. BRKELUND & Hansen (op. cit.) think that the structure of the septa THE VELIGER Vol. 21; No. 3 ee Figure 23 Jurassic ammonoids that had been decalcified before being fossil- ized in limestone. A: Glochiceras with the siphuncular tube in its original position. B: Subplanites in which sections of the siphuncular tube have separated and shifted towards the center before the onset of fossilization and the siphuncular tube described from Saghahalinites and Hypophylloceras (ammonoids from the upper Creta- ceous) indicate that the hydrostatic apparatus of nauti- loids and ammonoids are much more similar to each other than Mutve1 (op. cit.) suggested, but they do not pre- sent any data to demonstrate this. The siphuncular tube of the Ammonoidea and its at- tachment to the septum differ in several respects from those of Nautilus and Spirula. 1. The beginning of the siphuncular tube (caecum) ex- tends into the first ovoid chamber; it is similar to what we have seen in Spirula. But this blind ending is hemispherical; the thickness of its wall does not change (Branco, 1880; MirterR & UNKLESBAY, 1943; ERBEN, 1962: fig. 1; ERBEN & RED, 1971: plt. 1, fig. 4). This bulbous structure is continuous with Vol. 21; No. 3 THE VELIGER Page 345 Figure 24 Hypothetical swimming position of an ammonoid, with the pre- sumed distribution of liquid in the last chambers Figure 25 The siphuncular tube (st) of a Jurassic ammonoid, with the septa (s) cut above the folded lobes (1) by which they are attached to the shell wall. The arrow points towards the aperture of the shell. On the apertural part of each section of the siphuncular tube a pellicle (p) or a series of sheets form a cavity apart from the actual chamber. The septal necks (sn) are turned towards the apertural side of the shell an organic sheet that resembles that observed in Sp7- rula; it may also be branched, however (ERBEN, FLAJs & SIEHL, 1969). The structure of the siphuncular tube in the earliest ammonoids reminds one of the tube of nautiloids, for the septal necks are drawn out in the apical direc- tion. But for the majority of late Paleozoic and Meso- zoic ammonoids this situation reigns only at early de- velopmental stages (retrosiphonate, retrochoanitic). At the later growth stages, the septa first develop apertural projections where they make contact with the siphuncle, and eventually are entirely drawn out to the apertural side (prosiphonate, prochoanitic) (Branco, 1880: plt. 9, fig. 9; MILLER & UNKELSBaY, 1943). Thus the last septal neck of the semi-adult and adult ammonoid always points towards the living chamber (cf. Figure 26). Each portion of the siphuncular tube has the same length as the corresponding chamber (Figure 25). The walls of the tube are not continuous with the septal necks (Figure 26). It has been thought that the siphuncular tube consisted of phosphatic material (ARKELL, 1957; GRANDJEAN, 1910), but recent observations indicate that it is made of organic material similar to the horny tube of the Nautilus siphuncle (Mutve1, 1967; ErBEN, FLajs & SIEHL, 1969; ERBEN & RED, 1971). 4. The individual portions of the siphuncular tube are not fused with one another, so as to form one con- tinuous organic tube; instead they are connected by calcareous material (Mutvel, 1967, 1975; BoEH- MER, 1936; GRANDJEAN, 1910). Fossil ammonoids (Subplanites, Glochiceras) from the “Mornsheimer Schichten” (lower Tithonian, upper Jurassic) of the Horstberg near Mornsheim (South Germany) were completely decalcified before they became fossilized (Figures 23a, 23b). Only the outer ornamentation of the shell is found together with the non-calcareous siphuncular tube. Some specimens show this tube in its original dorsal position (Figure 23a); in others it has been shifted to a more central position (Figure 23b). This shifting of the tube must have occurred before the decalcified shells were compacted with the muddy sediment around them. In the original position, the individual tube portions are connected to one another in such a way that the apical part of each tube segment is narrower than the apertural part of the segment formed before (Figure 26). Ina decalcified shell not filled with sediment the tube seg- ments may easily have broken apart as soon as the Page 346 THE VELIGER Vol. 21; No. 3 Figure 26 A reconstruction of the septal neck (sn) and the attachment of the tween the rear end of a tube section and the septal neck turned to- siphuncular tube to the septal neck in adult ammonoids. The nac- wards the aperture of the shell (arrow), each chamber has large reous septal neck is a continuation of the septum (s). In addition to de-coupling rooms and a porous zone in the anterior part the de-coupling room (dr) and porous prismatic zone (pz) be- calcareous connecting material was dissolved, so that the siphuncular tube was free to shift inside the shell. 5. The descriptions and figures presented by BOEHMER (1836), Miter & UNKLESBAY (1943), ERBEN, FLAJS & SIEHL (1969) suggest that the organic portion of the siphuncular tube is continuous with the nacreous septal neck as in Nautilus, as long as the septal neck points to the apical side. Among the ammonoids, in general, this is only so at very early ontogenetic stages. Representatives of the Paleozoic Agathiceras are an exception to this rule in that the septal necks may even increase in length during the individual development until their length is § of the chamber length (MILLER « UNKLESBAY, 1943). In this genus we thus find septal necks similar to those of the Re- cent Spirula. The siphuncular tube of juvenile indi- viduals of many Mesozoic ammonoid species has a central or sub-central position. It gradually “mi- grates” to the outer part of the chamber and becomes marginal by the time when the third volution is reached (cf. ERBEN, FLajs & SIEHL, 1969: plt. 1). 6. With the change in the orientation of the septal necks during the ontogenesis of most ammonoids the si- phuncular tube becomes independent of the septum; it can only form after the septum is completed. The nacreous layers of the septal neck are therefore no longer continuous with the horny siphuncular tube. The latter is now attached to the septal neck by sec- ondary calcareous deposits. These may have been porous as in Nautilus. Figure 26 is a reconstruction of the attachment of the siphuncular tube to the sep- tal neck of an adult ammonoid. The drawing is based on data presented by MILLER & UNKLESBAY (1943: fig. 6 H; pit. 5, fig. 5) from species of the genera Eo- asianites and Perrinites (both ammonoids from the late Paleozoic), and by GrANDJEAN (1910: fig. 3) and Mutvet (1967: pit. 14, fig. 2; 1975: fig. 2) from species of the genera Ludwigia, Eleganticeras and Promicroceras from Jurassic strata. In the course of their ontogenesis the ammonoids thus developed an additional porous zone in the siphuncular tube; when the septal necks changed from a retro- to a pro-si- phonate arrangement, the chamber liquid could be drained at both ends of the tube segment crossing the chamber. 7. The siphuncular tube of the ammonoids is covered by an organic pellicle that separates from the tube near Vol. 21; No. 3 its end (Branco, 1880; Bo—EHMER, 1936; ERBEN & Rem, 1971; Bayer, 1975). The siphuncular tube is thus attached to the ventral shell wall. What is par- ticularly important is that this pellicle encloses spaces near the end of each tube segment that are not in direct contact with the actual chamber (Figure 25). Liquid could be held there independent of the main body of chamber liquid. The living chamber of dif- ferent species of ammonoids varies greatly in length, but usually amounts to more than 4 of a whorl (Ar- KELL, 1957). Thus the position of the last-formed chamber, which is still completely filled with liquid, is different from that of a new chamber in the Recent Nautilus. The liquid contents would have been in a position roughly as that shown in Figure 24. This is a situation very different from that shown to exist in Nautilus (DENTON & GILPIN-BRown, 1966). 8. In the majority of the ammonoids, the margins of the septum are corrugated and fluted (Figure 25). Thus many small indentations are formed between the in- ner face of the outer shell wall and the septum. In chambers only partially filled with liquid this mor- phological differentiation of the septal sides may have assisted in the de-coupling of the chamber liquid from the liquid contained in the pouches near the end of each segment of the siphuncular tube. This would have an effect similar to what we have seen in the cuttlebone of Sepia. HEPTONSTALL (1970) suggested that the individuals of the genus Buchiceras, which in their life have been en- crusted with oysters, have been able to maintain neutral buoyancy by removing liquid from the chambers. This author states that in all ammonoids a considerable amount of water would have been kept in the chambers for main- taining neutral buoyancy. Experimental studies by Mut- VEI & REYMENT (1973) carried out with plastic shell models confirmed that ammonoid shells in general have been more buoyant than Nautilus shells and that in order to maintain neutral buoyancy they must have had more liquid in their chambers. The model presented in our Figure 24 thus probably comes close to reality. In conclusion we may say that the ammonoids in gener- al have developed a “typical” siphuncular system allowing rapid disposal of the chamber liquid for buoyancy regula- tion with an effective de-coupling of the main body of chamber liquid from the liquid in closer contact with the siphuncular tissue. THE VELIGER Page 347 Belemnoidea Moutve1 (1971) described the siphuncular tube in repre- sentatives of the Aulacocerida and Belemnitida ftom Ju- Tassic strata. His pictures show that the structure of the pillar zones and the course of the siphuncular tube are strikingly similar to the Recent Spirula. The pillar zone extends a little further into the next older siphuncular tube, as it is slightly longer than one chamber. In contrast to Spirula, however, the siphuncular tube is organic ex- cept for the septal neck. Mutvei (1971) thought that the structural features of the belemnite siphuncular tube were neither represented in the Recent Nautilus and Spirula, nor in any known group of fossil cephalopods. The close relationship that actually exists between the siphuncular tube of Spirula and that of the belemnites, in terms of both their struc- ture and functioning (cf. Figure 27), was therefore not yet emphasized by Denton (1974). Referring to Mut- vei’s study, Denton suggested that this rather complicated structure might form a connection for liquid movements between one chamber and its neighbours. Mutve! (1971) suggested that the aulacocerids and the belemnitids had no need for porous layers on the wall of the siphuncular tube and that the whole wall of the tube was permeable. The liquid of the last-formed chamber would thus have been pumped across the 2 organic layers and the “semi-prismatic layer,” as Mutvei calls the pillar zone. He comes to the conclusion that belemnites, at least at juvenile stages, could not descend into deep water as Nautilus and Spirula do. In contrast to MuTver’s (1971) statement, but in ac- cordance with his figures 1 and 2 and with his plates, the siphuncular tube of the last-formed chamber in belem- nites did not consist of a double-walled organic tube with pillars between the 2 organic layers, but of a single tube the anterior part of which continues into the posterior pillar zone, as in the siphuncular tube of Spirula. A double tube can be found only in the second-to-the-last chamber. Considering the situation described from Spirula by DEN- TON & Gi_pIn-BRowNn (1971a), where only the last cham- ber is filled entirely or to a large extent with liquid, it seems likely that similar conditions existed in the belem- nites, 7. é., that the wall of the mainly organic tube was largely or entirely impermeable to liquid, so that contact between the chamber liquid and the siphuncular tissue was made through the pillar zone, as in Spirula; and that the chambers next to a double siphuncular tube were already empty. Page 348 THE VELIGER Vol. 21; No. 3 Figure 27 A comparison of the siphuncular systems of fossil and Recent cepha- lopods. A: Pseudorthoceras (redrawn from MutTVvEI, 1972). B: Nautilus. C: belemnoids (redrawn and re-interpreted af- ter Mutvel, 1971). D: Spirula. E: Sepia. Note the enlarge- ment of the pillar zone from B to E. In Pseudorthoceras no pillar zone is found, as in the ammonoids which have developed different Spirula is known to make extensive vertical migrations; it lives mainly below 200m, but usually does not descend deeper than 1000m. CLARKE (1970) showed that during the day Spirula stays at depths around 600 - 700m. Since the siphuncular tube of the belemnites appears to be rather strong, a vertical mobility similar to that of Spirula means of de-coupling liquid from the main body of chamber liquid. In Nautilus the pillar zone is small in comparison to the chamber volume. In the belemnites and in Spirula, the pillar zone is en- larged, but still chambers of considerable volume are present. In Sepia finally the pillar zone alone remains and fulfills the chamber function. can be presumed. The pillar zone represents a large space for liquid, apart from the main body of liquid in newly formed chambers, so that high osmotic pressures may have been established, enabling the belemnites to maintain neutral buoyancy at great depths. Vol. 21; No. 3 CONCLUSIONS on THE PHYLOGENETIC DEVELOPMENT oF THE SIPHUNCULAR SYSTEM The siphuncular system of the only living cephalopods that have a chambered shell is a very conservative struc- ture. This undeniable fact is partly obscured by the dif ferences in the gross morphology of the shells and their respective siphuncular systems in Nautilus, Spirula and Sepia. As we have seen that the structural elements of these 3 modifications of a common type of siphuncular system are very similar, it remains to be seen whether their for- mation is also similarly timed with the formation of a new chamber. Mutvet (19724) assumed that in Nautilus the lamellar pillars (“prismatic layer”) on the apertural side of the septum are formed as the final layer of a new septum before secretion of calcareous material ceases. It seems more likely, however, that the pillars are formed just before the pellicle that will cover them is secreted, and that these 2 steps initiate the withdrawal of the mantle, which is accompanied by secretion of body fluid into the new chamber now forming. In the “state of rest,” the epithelium of the mantle would thus closely join the smooth surface of nacre. In chronological terms, forma- tion of pillars would thus be the earliest of the events in the formation of a new chamber, similar to the sequence found in Spirula and Sepia. In Nautilus, the structure of the pillars is transitional to the columnar structures that are formed by nacre platelets piled up to pyramid-like complexes (MuTVEI, 19724) (Figures 93, 94). It is conceivable that such pillars have existed in the Paleozoic orthocone cephalopods, between the walls of successive calcareous siphuncular tubes (cf. DENTON, 1974: plt. 17). In the belemnites (MuTVEI, 1971) and in Spirula, the lamellar pillars are consistent with the lamellar structure, not with the nacreous structure. During the evolution of the endocochleate shell, the nacreous layer must have been transformed into the lamellar layer. To our knowledge, all ectocochleate cephalopods show only a nacreous struc- ture. Structures transitional between nacreous and lamel- lar are present, however, in the septal neck of Nautilus and Pseudorthoceras (MUTVEI, 1972a, 1972C). Spirula and the belemnites have a wide zone of the siphuncular tube occupied by the pillars. This pillar zone is distinct from the actual chamber. In Sepia, however, the actual chamber is lost, and the pillar zone is opened up into a broad blade. The organic sheets, confined to the anterior part of the pillar zone in Spirula, now extend THE VELIGER Page 349 throughout the “chambers” of the cuttlebone. No signifi- cant difference has been found between the structure of the lamellar pillars of Spirula and those of Sepia. Also the septa of Sepia and the anterior siphuncular tube of Spirula show the same composition of their lamellar struc- ture. The cuttlebone can withstand high external pressure. Sepia officinalis is known to live in coastal waters and to descend to a depth of about 150m. DENTON (1974) has shown that cuttlebones of Sepia officinalis implode at pres- sures around 20 atmospheres, which corresponds to a depth of about 200m. Other species of Sepia live at greater depths, however. Sepia elegans and S. orbignyana have been found on bottoms as deep as 450m (cf. Man- GOLD-Wirz, 1963). It is not surprising then that the strong shell of Nautilus can withstand pressures of 60 to 70 at- mospheres (DENTON & GILPIN-BRowNn, 1966), but the rather more delicate shell of Spirula regularly withstands pressures twice as high, and occasionally pressures cor- responding to depths of more than 2000m (DENTON & Grtpin-Brown, 19714). Since the structure of the siphuncular tube of the am- monoids and belemnoids known to date resembles so much the structures in Nautilus and Spirula, it seems reasonable to assume that these fossil cephalopods were able to descend into deep waters. DISCUSSION The only cephalopod with a chambered shell of which we know the embryonic development is Sepia. Although this particular development cannot be taken as representative in every detail for other cephalopods, Recent or fossil, that have a calcified, chambered shell, it is at any rate interesting to consider very carefully all the features of Sepia embryos that might present signs of ancestral fea- tures. Setting aside the question of whether or not the closure of the shell sac in the embryo of Recent Coleoidea is a recapitulation of the process by which the external shell of ectocochleate cephalopods has been surrounded by the pallial integument to become the internal shell of the endocochleate type, one wonders what the phenomena of folding and stretching of the shell sac epithelium at the early stages of shell formation in Sepia embryos signify. One wonders whether these phenomena are related to the formation of the so-called “cicatrix” in the shell of the Recent Nautilus and of certain fossil Nautiloidea. The morphological features of the Sepia protoconch closely match the definition of the cicatrix as given by ERBEN & Fiayjs (1976). The presence of such a structure in the Page 350 protoconch cannot be taken, however, as an indication of the presence or absence of a post-embryonic larval phase. Considering the morphological relationship of the fins to the shell complex, one may formulate several hypo- theses on the origin of these special locomotory organs. For example, it is conceivable that the cephalopod fins are derived from originally larval “appendages” that al- ready served locomotion. This hypothesis could lead to the construction of a larva that had some similarity with a typical veliger, but in which the locomotory appendages (equipped with cilia) were part of the pallial complex, in contrast to the cephalic vela. If some or all ammonoids had true larvae, these lar- vae may have been anything but veligers of, e. g., a gastropod-like appearance as figured by ERBEN (1964) (cf. also JAGERSTEN, 1972). Before one attempts to interpret the sequence of cal- careous formations deposited on the early organic shell of Sepia, one must of course be certain that the steps con- sidered are well distinguished. Looking through the lit- erature, one finds a great deal of contradiction and con- fusion as to the first appearance of certain shell structures. Thus KorLuiker (1844) correctly stated that the first em- bryonic shell of Sepia is not mineralized. APPELLOF (1893) doubted that these observations were correct, as he had found only calcified shells in the embryos he dissected. Koelliker also correctly observed that in the earliest em- bryonic chambers of the cuttlebone, the pillars are more regularly columnar than in the later chambers, whereas Appellof made no differentiation between the pillars of the earliest and those of the later chambers. However, APPELLOF (1893) correctly stated that the fork is not yet formed in the embryonic cuttlebone, where- as Narr (1928) was convinced he saw the fork layer cor- responding to each embryonic chamber. Spiess (1972) also thought that all parts, including the spine, were well differentiated in the embryonic cuttlebone, but he found no horizontal organic sheets in the embryonic chambers. These are present, however, whereas the spine begins to form only towards the end of embryonic development in Sepia officinalis. If the fork and the spine were ancestral features, one would indeed expect to find them among the earlier differentiations of the shell. As we do not yet know the embryonic development of Spirula, we are again restricted to hypotheses. These will necessarily be misleading if the structural properties of the initial chambers are not considered in every detail. Although AppELL6rF’s (1893) idea of the formation of the first chamber of Spirula was hampered by his assump- tion that this chamber is originally filled with soft chitin, his description of the first chamber is correct. NAEF (1928), however, saw a double-layered structure in the THE VELIGER Vol. 21; No. 3 outer wall of the first chamber, and a rudimentary septum continuous with the septal neck. But the ridge-like con- striction of the inner apertural wall of the first chamber has no structural similarity with the actual septa, and it is not continuous with the septal neck. Furthermore, NAEF (op. cit.) noted a feeble calcification of the “prosipho,” and he mentions a transversal supporting rod (“Sagittal- lamelle”) lying between the “prosipho” and the ventral chamber wall (Naer, op. cit.: text fig. 279a). Such an additional lamella does not exist, and the “prosipho” sheet shows no trace of calcification. The morphology and the fine structure of the first chamber in Spirula, with its blindly ending siphuncular tube, is very similar to the first chamber of ammonoids with the so-called caecum. A comparison of the first chamber of Spirula, opened up (Figure 64), and the first chamber of the ammonoid Eleganticeras (LEHMANN, 1976) will show this. SCHINDEWOLF (1933) suggested that a caecum of the type known from Spirula and the ammonoids rep- resents the primitive situation, and that the siphuncular end as it now exists in the first chamber of Nautilus is the result of a secondary differentiation. The shell structure of the first chamber (ERBEN, FLays & SIEHL, 1968, 1969; Kuuickl, 1975) and of the prosep- tum and flange in ammonoids also shows great similarity between different ammonoid species on the one hand, and Spirula on the other. There is one important difference, however, in that Spirula shows a constriction between the first and second chamber that is much stronger than subsequent ones, whereas the ammonoid shell presents an even spiral growth from the beginning. Only in some am- monoideans of the early Devonian age, when the coiling of the first whorl was still evolute, as it is in Spzrula, a constriction reminiscent of the early Spzrula shell has been observed (ERBEN, 1964) ; a similar feature has also been noted in longicone nautiloids (ScHINDEWOLF, 1933). In the literature we find two opinions as to the devel- opment of the first septum in the ammonoids. One is based on the observations of ErBEN (1964) and ErRBEN et al. (1968, 1969); it claims a free larval life for the young. The other is expressed by BRKELUND & HANSEN (1968, 1974), DrusHits & Kutami (1970), and by Kuutcx1 (1974, 1975); it suggests that the ammonoids had a di- rect development, corresponding to what is known of all the Recent coleoid cephalopods so far studied (cf. BoLeTzky, 1974b). In the first theory, three phases similar to those of gastropod and lamellibranch metamorphosis are postu- lated. In the first phase, the early embryonic shell gland produces a shallow, bowl-shaped protoconch or a simple organic cap. This early formation is enlarged until a shell of nearly one complete whorl is formed. With this Vol. 21; No. 3 shell, the animal hatches as a larva similar to a prae- veliger or trochophora. In the shell, this stage would be marked by a constriction and a condensation of growth lines. In the second phase, a free swimming, planktonic veli- ger or veliger-like larva adds shell material to the aper- ture in such a way that a ventral indentation forms, re- flecting the ventral position of the velum. The secondary walls of the embryonic shell are then added. Only shortly before the end of the larval phase, the “flange” and the “proseptum” are formed (the flange is the first prismatic addition to the ventral inner side of the shell; the pro- septum is the constriction of the aperture of the first chamber). The siphuncle now differentiates. The end of metamorphosis and the beginning of the third phase is documented by the so-called nepionic con- striction, a distinct mark in the shell wall; the prismatic shell layers wedge out, or the direction of their growth is suddenly inverted, apparently due to a temporary re- treat of the mantle edge. The first nacreous layers are formed and the buoyancy apparatus becomes functional with the formation of the first primary septum that closes the second chamber. This first septum may have a pris- matic (ERBEN, FLajs & SIEHL, 1968, 1969) or a nacre- ous structure (BIRKELUND & HANSEN, 1974; KULICKI, 1975)- The second theory was formulated by Kuticx1 (1974, 1975). According to this theory, the embryo first forms a cup-shaped prismatic shell, the aperture of which is then reduced by the addition of shell material on the ventral inner side, which forms the flange. Immediately after this, another constriction (proseptum) is formed next to the flange. During further growth, the soft tissue filling the initial chamber is withdrawn, and the epithelium separates from the wall of the first embryonic shell. Only a minute part of it remains attached at the end of what will become the “prosipho” (organic sheet between the end of the siphuncular tube and the chamber wall). Along with this, the wall of the proseptum grows to become an annular constriction (as a continuation of the initial vent- ral ridge in front of the flange that is also ventral). After the proseptum, the prosipho and the caecum take shape as soon as the tissue is withdrawn from the first chamber. In the ammonoid genus Quenstedtoceras,a newly hatched animal would have 3 complete chambers, if the nepionic constriction marks the stage of shell growth reached at hatching. TRUEMAN (1940) reports on shells with 3 septa and a diameter of 0.5 to 0.6mm, which he considers to be the shells of newly hatched Arnioceras. In Spirula, the construction of the shell wall has been described in different ways (cf. DauPHIN, 1976). APPEL- LOF (1893) noted 2 layers, the inner primary and the THE VELIGER Page 351 outer secondary. BacciLp (1930) found that the inner shell wall consists of regular prisms, whereas the outer part would be homogeneous. It is very likely that Boggild observed the layers of the primary wall only. Mutver (1964a) stated that a periostracum is not known from the Spirula shell. NaEF (1928) gave a description that comes close to the actual structure of the Spirula shell. He found 3 layers, of which the thickest is the middle layer that consists, according to him, of a somewhat irregular nacre (lamellar layer!). Our observations make it clear that a lamellar layer makes up the bulk of the shell wall, with an underlying prismatic layer. This innermost layer shows only the structure that was thought to compose the entire primary wall, according to Mutvei’s description. If the central layer with its lamellar structure is considered to be similar to the nacreous layer of Nautilus, the shell wall of Spirula certainly appears very similar to the wall of the Nautilus shell. In contrast to Mutvei’s assumption that the superior part of the epithelium lining the “living chamber” of Spirula can produce only prismatic layers (outer wall), whereas the posterior parts produce 4 differ- ent layers of the septum and the siphuncular tube, we can now state that the epithelium lining the “living chamber” can produce similar aragonitic deposits independent of their position in the chamber. In his analysis of the Spirula shell, Mutver (1964a) found that the septal and siphuncular deposits retained their original structure, being made up of the same 4 layers as the shell of Nautilus. Mutvei observed that these 4 layers are visible in the newly formed siphuncular tube only; in the posterior part of the tube which he thought is formed later, these deposits are reduced and consist of a single layer, the spherulitic-prismatic layer. In Mutvei’s view, the posterior parts of the siphuncular tube of Spiru- la are at an advanced stage of reduction as compared to the corresponding formations of Nautilus. The septum and the anterior part of the siphuncular tube are assumed to be made of an outer conchiolin layer (organic layer), a spherulitic-prismatic layer, a nacreous layer, and an inner semi-prismatic layer. We can not confirm these ob- servations of Mutvei. Depending on the part of the shell, one finds different sequences of layers (cf. Figure 7). In a diagrammatic presentation of the shell and its epithelium, Mutver (1964: text fig. 28) figures a newly formed septum with the epithelium and the siphuncular tube that extends through 14 chambers. On the anterior part of the siphuncular tube, which has just been formed, pillars are present. Mutvei states that the semi-prismatic layer (pillar zone; “Pfeilerchen” of Appellof) forms a continuous coat on the ventral face of each septum and that it also invests the inner face of the siphuncular tube. Our observations indicate that this reconstruction is er- Page 352 roneous, as the pillars in fact are formed along with a new septum and anterior part of the siphuncular tube. APPELLOF (1893) described the annulations of the pillars and the organic sheets between the anterior pillars in Spirula and compared them to the corresponding struc- tures of the Sepia shell. He also noted the coarse structure of the pillar apices, especially near the posterior end of the pillar zone, where pillars and needle aggregates are interlaced. and he compared this area with the posterior part of the siphuncular area in Sepia, where crystal aggre- gates are also present. These very clear similarities were not recognized by Narr (1928) who differentiated be- tween a calcareous tube (“Kalkdiite”), into which an organic tube (‘“‘Conchindiite) were fitted. The lamellar structure that forms, according to Mut- vEI (1964a, 1964b, 1970), the type of nacre found in bel- emnoids and in Spirula differs in one important point from the nacre of gastropods, pelecypods and of Nautilus. In the lamellar layers, there are no concrete tabular plates of a certain size that is characteristic of each shell section, because the small components of each platelet may vary in size. Interlamellar partitions of organic shell material are not distinct in the lamellar layers, so that they do not present, in a section, the appearance of brickwork or stacks of coins that is so typical of nacre. Although the lamellar structure may have developed from the nacreous structure, or vice versa, they are clearly distinct structures. This is also indicated by the different composition of the organic septal material in Nautilus and in Spirula (Gréc- ORE, 1961, 1962). DENTON & GiLpIN-BRown (1961b) showed that the oldest (embryonic and early post-embryonic) chambers of the Sepia shell are almost completely filled with liquid at the adult stage. These authors found that nevertheless these oldest chambers can again be pumped out. In large individuals of Sepia officinalis and S. orbignyana, the si- phuncular zone of the oldest chambers is often covered with a secondary calcareous deposit. When this is present, the respective chambers can probably no longer be pumped out by the siphuncular epithelium. In Sepia pharaonis, younger individuals already show this kind of mineral cover on the siphuncular zone of the oldest chambers, with an additional lamellar, mainly organic deposit uppermost (Figure 4). Thus, the oldest chambers, which are refilled with liquid, are completely sealed up. Although we know very little of the function at the cellular level of the different parts of the shell sac epi- thelium, it is clear that the epithelium of the siphuncular zone fulfills very different tasks, according to the differ- ent phases of shell formation. It first takes a part in the formation of the chamber layers, then acts as a “pumping organ” when the chamber is emptied, and finally part of THE VELIGER Vol. 21; No. 3 it secretes the calcareous and organic components of these last shell deposits on the ventral side of the cuttlebone. The great change in the histological aspect of the epi- thelium during the first two steps has been described by DENTON & GrLpIN-BRowN (1961a). Finally, it can be conjectured that the secondary cal- careous deposits on the posterior part of the siphuncular zone of the Sepia shell correspond to the intra-siphuncular deposits that are observed in many Paleozoic cephalopod shells. Deposits that are not calcareous, however, are found in the siphuncular tube of the first chamber of Spirula (Figure 66), and also in the first-formed parts of the siphuncular tube of Nautilus. These translucent or- ganic deposits completely fill the tube so that the siphun- cular tissue is no longer in contact with the first chambers. SUMMARY 1. The structural composition of the shell is essentially alike in Sepia and Spirula, notwithstanding their very dissimilar form. The lamellar structure composes the septa and the greater part of the wall in the cuttlebone and in the Spirula shell. The inner prismatic layer of the Spirula shell is homologous to the inner layer of the Sepia shell. The external spherulitic-prismatic layer that is produced by the secondary shell epithelium is alike in both types of shell. 2. The early embryonic shell or protoconch of Sepia is different from that of Spzrula. The former shows simi- larities to the protoconch of Nautilus and many fossil Nautiloidea, whereas the shape and composition of the early Spirula shell resemble very much that of the Am- monoidea and Belemnoidea, including the first pris- matic apertural constriction (proseptum) and the end of the siphuncular tube (caecum) with its sheet-like extension that is fixed to the shell wall. Sepia and Nau- tilus both show a groove in the initial organic shell cap, the so-called cicatrix. The similarity of these structures suggests an identical configuration of the respective parts of the primary epithelium. So far, the embryonic development of Sepia only is known. 3. The lamellar structure is composed of 0.1 - 0.3 um units, similar to the composition of other biocrystal structures of higher organisation known from the mol- luscs: nacre, crossed lamellae and the helical structure. Like the closely related nacreous structure, the lamellar structure is elaborated in gelatinous lamellae that have the same thickness as the crystalline lamellae. 4. The siphuncular system js essentially alike in Sepia and Spirula, as the so-called chambers of the cuttlebone Vol. 21; No. 3 THE VELIGER Page 353 represent the siphuncular system and septal necks of the Spirula shell. The actual chamber of Spirula is not rep- resented in the Sepia shell. The septal neck (lamellar structure) of Spirula is homologous to the septum of Sepia, and the pillars of the siphuncular wall of Spirula are homologous to the chamber pillars of the cuttle- bone. The irregular crystals and crystal aggregates in the posterior part of the siphuncular zone of each cuttlebone chamber are homologous to the very similar structures found in the posterior part of the siphuncular tube in Spzrula. 5. The function of the siphuncular system has probably never changed in the chambered shells of cephalopods. With the suppression of the actual chamber in the Sepia shell, the “main body of liquid,” which in the chambers of other shells is “de-coupled” from the small part of liquid in contact with the siphuncular wall, is no longer a distinct component of the buoyancy apparatus; rather the innermost parts of the cuttlebone chambers are fluid reservoirs that are analogous to the actual chamber as a reservoir. Literature Cited Apa, Wiviiam e WicuiaM J. Rees 1966. A review of the cephalopod family Sepiidae. Exped. 1933-34, Scientif. Reprt. 11 (1): 1-165 ApPreELLor, A. 1893. Die Schalen von Sepia, Spirula und Nautilus. Studien tiber den Bau und das Wachstum. Kongl. Svensk. Vetensk. Akad. Handl. 25 (7): 1-106 John Murray ARKELL, W. J. 1957. Introduction to Mesozoic Ammonoidea. In: Treatise on Invertebrate Paleontology, prt. L, Mollusca 4: L81-Li2g. R. C. Moore, ed. BANDEL, Kraus 1975a. Embryonalgehause karibischer Meso- und Neogastropoden (Mollusca). Abh. math. naturwiss. Kl. Akad. Wissensch. u. Lit. Mainz, Jahrg. 1975, 1: 1 - 133 1975b. Embryonale und larvale Schale einiger Prosobranchier (Gastro- poda, Mollusca) der Oosterschelde (Nordsee). Hydrobiol. Bull. Amsterdam 9: 3 - 22 1975c. Das Embryonalgehause mariner Prosobranchier der Region von Banyuls-sur-Mer. 1. Teil. Vie et Milieu 25: 83-118 1975d. Entwicklung der Schale im Lebenslauf zweier Gastropodenarten: Buccinum undatum und Xancus angulatus (Prosobranchier, Neogastro- poda). Biomineralisation 8: 67 - 91 1977a. Ubergiange von der Perlmutter-Schicht zu prismatischen Schicht- typen bei Mollusken. Biomineralisation 9: 28 - 47 1977b. Die Herausbildung der Schraubenschicht der Pteropoden. Biomineralisation 9: 73 - 85 Banper, Kiaus & CuristopH HeEMLEBEN 1975. Anorganisches Kristallwachstum bei lebenden Mollusken. Palaont. Zeitschr. 49: 298 - 320 Bayer, ULF 1975. Organische Tapeten im Ammoniten-Phragmokon und ihr Ein- fluss auf die Fossilisation. Neues Jahrb. Geol. Palaont. Mh., 1975 (1): 12-25 BirKELUND, Tove « H. J. Hansen 1968. Early shell growth and structures of the septa and the siphun- cular tube in some Maastrichtian Ammonites. Medd. Dansk. Geol. Foren Kebenhaven 18: 71 - 78 1974. Shell ultrastructure of some Maastrichtian Ammonoidea and Coleoidea and their taxonomic implications. Kong. Dansk. Vidensk. Sel. Biol. Skrift. 20 (6): 1-34 Buinp, WoLFRAM 1976. Die ontogenetische Entwicklung von Nautilus pompilius (Lin- né), Palaeontograph. 153: 117 -~ 160 Baccitp, O. B. 1930. The shell structure of the mollusks. sk. Selsk., nat.-mat. Afd. 9 Rk. 2: 231 - 326 Bozumers, Jouan GC. A. 1936. Bau und Struktur von Schale und Sipho bei Permischen Ammon- oidea. Drukk. Univer. Apeldoorn, 125 pp. Bo.etzxy, SicurD v. 1974a. Effets de la sous-nutrition prolongée sur le développement de la coquille de Sepia officinalis L. (Mollusca, Cephalopoda). Bull. Soc. Zool. France 99: 667 - 673 1974b. The “larvae” of Cephalopoda: A review. sl. 10 (1/2): 45-76 Bovetzky, SIGuRD v. & MARIA VzERENA v. BOLETZKY Skr. kgl. Danske Viden- Thalassia Jugo- 1973. | Observations on the embryonic and early post-embryonic de- velopment of Rossta macrosoma (Mollusca, Cephalopoda). Helgo- lander wiss. Meeresunters. 25: 135 - 161 Branco, W. 1880. Beitrage zur Entwicklungsgeschichte der fossilen Cephalopoden. Palaeontograph. 27: 12 - 81 Cuun, Cari 1910. Spirula australis Lam. Bericht. math.-phys. Kl. Kgl. Sachs. Gesellsch. Wissensch. Leipzig 62: 171 - 188 CiarKe, Matcoim R. 1970. Growth and development of Spirula spirula. biol. Assoc. U. K. 50: 53 - 64 DauPHiNn, YANNICKE 1976. Microstructure des coquilles de Céphalopodes. I. Spirula spirula L. (Dibranchiata, Decapoda). Bull. Mus. Nat. Hist. nat. (3) 54 (382): 197-238 Denton, Eric J. 1974. On buoyancy and the lives of modern and fossil cephalopods. Proc. Roy. Soc. London B 185: 273 - 299 Denton, Eric J. & JouN B. Gitpin-BROwN 1961a. The buoyancy of the cuttlefish Sepia officinalis (L.). Journ. mar. biol. Assoc. U. K. 41: 319 - 342 1961b. The distribution of gas and liquid within the cuttlebone. Journ. mar. biol. Assoc. U. K. 41: 365- 381 1966. On the buoyancy of the pearly Nautilus. Assoc. U. K. 46: 723 - 759 1971. Further observations on the buoyancy of Spirula. Journ. mar. biol. Assoc. U. K. 51: 363 - 373 Denton, Eric J., JoHNn B. Gitpin-Brown & J. V. HowartH 1961. | The osmotic mechanism of the cuttlebone. Journ. mar. biol. Assoc. U. K. 41: 351 - 364 1967. On the buoyancy of Spirula spirula. U. K. 47: 181-191 Drusuits, V. V. & N. KHIAMI 1970. Stroenie sept stenki protokoncha i naéalnych obrotov rakoviny nekotorych rannemielovych ammonitov. Paleont. Zurnal 1: 35 - 47 Ersen, HeinricuH K. 1962. Uber den Prosipho, die Prosutur und die Ontogenie der Ammo- noidea. Palaont. Zeitschr. 36: 99 - 108 1964. Die Evolution der Altesten Ammonoidea (Lfg. I). Neues Jahrb. Geol. Palaont., Abh. 120: 107 - 212 1974. On the structure and growth of the nacreous tablets in gastro- pods. Biomineralisation 7: 14 - 27 Ersen, Henrich K. e Gerp Fiajs 1975. Uber die Cicatrix der Nautiloideen. Inst. Univ. Hamburg 44: 59 - 68 Ersen, Heinricn K., Gerp Fiajs & AGAMAR SIEHL 1968. Ammonoids: Early ontogeny of ultramicroscopical shell structure. Nature 219: 396 - 398 1969. Die frithontogenetische Entwicklung der Schalenstruktur ecto- cochleater Cephalopoden. Paleontographica, Abt. A, 1392: 1-54 Ersen, Heinrich K. « R. E. H. Rep 1971. Ultrastructure of shell, origin of conellae and siphuncular mem- branes in an ammonite. Biomineralisation 3: 22 - 31 GraANDJEAN, F 1910. Le siphon des ammonites et des belemnites. France 10: 496 - 519 Grécore, Cx. ace ; 1961. Sur la structure de la nacre septale des Spirulidae, étudiée au microscope électronique. Arch. internat. Physiol. Biochim. 69 (3) : 374-377 ; 1962. On submicroscopical structure of the Nautilus shell. Bull. Inst. Roy. Soc. Nat. Belg. 38 (49): 1-71 Journ. mar. Journ. mar. biol. Journ. mar. biol. Assoc. Mitt. Geol. Paldont. Bull. Soc. géol Page 354 THE VELIGER Vol. 21; No. 3 HEPTONSTALL, WILLIAM B. 1970. Buoyancy control in Ammonoids. Huxvey, THomas H. « PaAuL PELSENEER 1895. Observations sur Spirula. Bull. scient. France Belg. 26: 1 - 55 JAEGERSTEN, GOESTA 1972. The evolution of the metazoan life cycle. 282 pp. JEuNIAUXx, CHARLES 1963. Chitine et chitinolyse. Jousin, Louis 1910. Observations sur une jeune Spirula. 165: 1-15 Kae in, IGNAz 1967. Beobachtungen iiber den Feinbau des Schulpes von Sepia offi- cinalis. Rev. Suisse Zool. 74: 596 - 602 Kawacutl, S. & A. ODA 1963. Electron microscopy on the cuttlebone-producing cells. Biol. Journ. Okayama Univ. 9: 41 - 53 Kerr, J. GRAHAM 1931. Notes upon the DANA specimens of Spirula and upon certain problems of cephalopod morphology. Oceanogr. Rprt. “Dana” Exped. 1920-22, 8: 1 - 36 Koe.uiker, ALBERT 1844. Entwicklungsgeschichte der Cephalopoden. Zurich Kuuicxi, Cyprian 1974. | Remarks on the embryogeny and postembryonal development of Ammonites. Acta Palaeont. Polon. 19 (2): 201 - 224 1975- Structure and mode of origin of the Ammonite proseptum. Acta Palaeont. Polon. 20: (4): 535-542 LEHMANN, ULRICH 1976. Ammoniten. Ihr Leben und ihre Umwelt. 171 pp. : MANGOLD, KaTHARINA 1963. Biologie des céphalopodes benthiques et nectoniques de la Mer Catalane. Vie et Milieu, suppl. 1g: 1 - 285 1966. Sepia officinalis de la Mer Catalane. Vie et Milieu 17 A: Lethaia 3: 317 - 328 Acad. Press. Masson & Co., Paris. 181 pp. Bull. Inst. Océanogr. Enke, Stuttgart, 961 - 1012 Mituzr, A. K. « A. G. UNKLESBAY 1943. The siphuncle of late Paleozoic ammonoids. Journ. Paleont. 17 (1): 1-25 Mutve!, Harry 1964a. On the shells of Nautilus and Spirula with notes on the shell secretion in non-cephalopod molluscs. Ark. Zool. 16 (14): 221-278 1964b. Remarks on the anatomy of Recent and fossil cephalopods. Stockholm Contr. Geol. 11: 79 - 102 1967. On the microscopic shell structure in some Jurassic ammonoids. Neu. Jahrb. Geol. Palaont. Abh. 129: 167 - 176 1970. Ultrastructure of the mineral and organic components of mol- luscan nacreous layers. Biomineralisation 2: 48 - 61 1971. The siphonal tube in Jurassic Belemnitida and Aulacocerida (Cephalopoda: Coleoidea). Bull. geol. Inst. Univ. Upsala, N. S. 3 (3): 27-36 1972a. Ultrastructural studies on cephalopod shells. Part I. The septa and siphonal tube in Nautilus. Bull. geol. Inst. Univ. Upsala, N. S. 3 (8): 237 - 261 1972b. Formation of nacreous and prismatic layers in Mytilus edulis L. (Lamellibranchiata). Biomineralisation 6: 96-100 1972c. Ultrastructural studies on cephalopod shells. Part II. Ortho- conic cephalopods from the Pennsylvanian Buckhorn Asphalt. Bull. geol. Inst. Univ. Upsala, N. S. 3 (9): 263 - 272 1975. The mode of life in ammonoids. Palaont. Zeitschr. 49 (3): 196 - 202 Mutver, Harry & R. A. REYMENT 1973. | Buoyancy control and siphuncle function in ammonoids. Palaeontology 16: 623 - 636 Naer, ADoLF 1922. Die fossilen Tintenfische. Gustav Fischer Verl., Jena, 322 pp. 1923. Die Cephalopoden. Fauna Flora Golfo Napoli, 35th monogr. I: 1-148; 37 plts.; text figs. 1 - 62 1928. Die Cephalopoden. Fauna Flora Golfo Napoli, 35th monogr. 2: 149-863; text figs. 63-473 Rupatt, K. M. « W. KeNcHINGTON 1973. The chitin system. Biol. Rev. 48: 597 - 636 ScHINDEWOLF, OTTO 1933. Vergleichende Morphologie und Phylogenie der Anfangskam- mern tetrabranchiater Cephalopoden. Abh. Preuss. Geol. Landes- anstalt, neue Folge 148: 1-115 Spiess, Pau E, 1972. Organogenese des Schalendriisenkomplexes bei einigen coleo- iden Cephalopoden des Mittelmeeres. Rev. Suisse Zool. 79 (1): 167 - 226 Tompsetrt, D. H. 1939. Sepia. L. M. B.C. Mem. 32, 184 pp. Univ. Liverpool Press TRuEMAN, ARTHUR E. 1940. The ammonite body-chamber, with special reference to the buoyancy and mode of life of the living ammonite. Quart. Journ. Geol. Soc. 96: 339 - 378 Vol. 21; No. 3 THE VELIGER Page 355 First Record of Okema impexa Marcus, 1957 from the Western Atlantic in the Mediterranean LUISE SCHMEKEL Zoologisches Institut der Universitat, HiifferstraBe 1, D 4400, Miinster, Bundesrepublik Deutschland (1 Plate; 2 Text figures) INTRODUCTION During a study of the Nudibranchia of the western Medi- terranean, we collected 2 rare species at Naples and at Banyuls: Okenia mediterranea (von Ihering, 1886), which has not been mentioned since Ihering, and O. impexa Marcus, 1957, from Sao Paulo and North Carolina. Be- cause there are some consistent differences between the Mediterranean and the western Atlantic material, the anatomy of the Mediterranean O. impexa is described here. We hope that on the basis of this description further research in the western Atlantic will help to decide wheth- er the species has entered recently into the Mediterranean or whether it is a geographical subspecies. GoNIODORDIDAE Eudoridacea suctoria, phanerobranchiate, rhinophores laminated without sheaths. There is a narrow pallial ridge on the head and on the sides, with or without simple appendages —- or the pallial ridge is reduced and there are only appendages. Radula without medi- an tooth, often with 2 lateral teeth, the inner one hook- shaped and larger than the often plate-shaped marginal tooth. Labial cuticle smooth or armed with hooklets or plates. Okenta Menke, 1830 Body with a narrow pallial ridge with simple append- ages. The anterior border of the notum is developed as a narrow, sometimes bilobed frontal velum. Rhin- ophores often laminated only behind. Gills often uni- pinnate. Radula formula 1-1-0-1-1. First lateral tooth large and hook-shaped with a smooth or dentic- ulated inner border. Outer lateral tooth small, plate- shaped with 1, 2 or 3 cusps. Labial cuticle smooth or armed with hooklets or plates. Penis armed with cutic- ular spines. Okenia Menke, 1830 (on official list no. 1995, Bull. Zool. Nomencl. 1974: 13). Type species: Idalia ele- gans Leuckart, 1828 (Figure 2). MENKE, Synopsis methodica molluscorum generum omnium 1830: 10. For discussion see: BeRGH, 1881: 144; 1907; BurRN, 1971: 151; LEMCHE, 1971: 262 - 266; Marcus, 1957: 434 ff; Marcus & Marcus, 1967: 203. I agree with Marcus (1957: 436) and Burn (1971: 151), that the division made by Bercu (1881: 144) into the subgenera Okenia s. str. (Bergh: Idalia s. str.) (with appendages in the middle of the back) and Jda- ltella (without such appendages) is not natural. Okenia impexa Marcus, 1957 (Figures 1a, 1b, 4, 5) Material: Banyuls: 5 specimens, alive, 3 - 4mm length, 1 - 20 September 1976; on Halimeda and Corallinaceae, 15m near Cap Oullestreil and 5 m near Collioure. Naples: 2 specimens, 3 - 4mm length, 11 March 1977, 7m, sand. Description: Descriptionof anundamaged animal found on Halimeda in 12- 15m depth in front of Cap Oullestreil, 14 September 1976. The genital organs and the radula of a 2" specimen of the same length are described. Alive and extended, the body is 4 mm long with a maxi- mum height and width of 0.8mm. The notum isnot broad- er than the foot and is bordered frontally and laterally by a distinct pallial ridge. Caudally the notum merges without pallial ridge into the 1.5mm long tail. Around the head, the pallial ridge bears 6 digitiform, apically pointed, rather stiff appendages (another specimen has only 4, a 3" one, 5 appendages), the 4 anteriormost of which are about 1mm long, and longer than both lateral ones. Behind the rhinophores the pallial ridge has 5 cerata on each side, the last 2 are united at their bases. From cephal to caudal, these lateral cerata increase to a length of 0.8mm. They have a characteristic shape, swell- Page 356 THE VELIGER Vol. 21; No. 3 ed and rounded at the tip, but extremely narrowed at the base. Halfway between the rhinophores and gills a low longitudinal median cresta begins, which ends at the gills. It bears one short, finger-shaped, pointed tubercle in front of the gills. The rest of the notum is smooth without any tubercles. The 0.8mm wide foot possesses short, 0.1mm long, protruding and pointed front angles and is pointed behind. The smooth anterior border of the foot is neither horizontally grooved nor medianly notched. The head is covered by a small bilobed veil, only slight- ly set off from the head on the sides. Extended, the rhinophores have a length of 1.2mm with a maximum diameter of 0.2mm. They are smooth in front and laminated with 10 leaflets behind only, from the tip almost to the base. Four simple pinnate gills, which have a maximum length of 0.8mm, insert tightly around the anus, which is situated 2.2 mm from the anterior border of the body. 0.03 mm re Figure 4 Okenia impexa Radula: (a) 1 lateral tooth - (b) denticulated inner border of The genital openings are situated somewhat behind the rhinophores and closely below the right pallial ridge. The labial armature consists of a thin cuticular ring without recognizable papillae. The radular formula (Figure 4) of an animal of 4mm is 15 X 1°1°0°1°1. The radula rhachis shows no cuti- cular support. The 1* lateral tooth is strongly hook-shaped and twice as long as the plate-shaped marginal tooth. Basis (0.06 mm) and tip (0.05 mm) of the 1" lateral tooth stand in a more or less straight angle towards one another. Its tip bears on the inner border about ro pointed den- ticles, which decrease from the tip towards the basis. The marginal tooth is 0.027mm high and 0.018mm wide. It possesses a sharp cusp and its edge has one hook-shaped denticle. The specimens of 3 and 4mm body-length copulated. Nevertheless, no egg masses could be observed. One day after copulation, the genital organs of a 4mm long ani- mal were studied (Figure 5). The hermaphrodite duct enters into a wide ellipsoid ampulla. The postampullar hermaphrodite duct is enclosed by the well-developed, swollen female gland mass in such a way that its proper course can not be pursued. Immediately behind the bi- furcation of the spermoviduct, the vas deferens increases to a long, big prostatic tube, which encloses the ampulla. The prostate occupies about # of the length of the vas deferens. It continues into a short ductus ejaculatorius, which ends in a penis, armed with pointed cuticular spines. The sheath of the penis closely encloses the penis. Between the sheath of the penis and the vagina a gland is situated, which appears white, compact and grape-like after fixation. The vagina is a straight duct, which runs beside the penis into a common vestibulum. At the wide vaginal duct a spherical bursa and an ellipsoid recep- taculum insert close to one another. Both vesicles appear to have a short stalk. Nevertheless, their mode of inser- tion could not be clearly established because of their tight filling. The general body colour is a bright transparent whit- ish yellow. The rhinophores, the gills and the cerata as well as the pallial ridge and the median cresta show, almost uniformly, this transparent yellow. On the notum the 1*t lateral tooth - (c) marginal tooth and the sides of the foot there is a dense, fine brown (in Explanation of Figures 1 to 3 Figures ra, rb: Okenia impexa Marcus, 1957 4mm Figure 2: Okenia elegans (Leuckart, 1828) (Banyuls) 5mm Figures 3a, 3b, gc: Okenia mediterranea (von hering, 1886) 4mm THE VELIcER, Vol. 21, No. 3 [ScHMEKEL] Figures 1 to 3c Figure 2 Figure ja Vol. 21; No. 3 THE VELIGER Page 357 0.1 ium Figure 5 Okenia impexa Reproductive system: (a) anatomy - (b) schematic Am — ampulla B - bursa D. ej. — ductus ejaculatorius Ov — oviduct Va — vagina Rec —- receptaculum seminis Vdr — vestibulum gland Pr — prostate artificial light red-brown) punctation, which is the most distinct on head and back, the most weak on velum and tail. The sides of the body show an average brown pig- mentation. Moreover, some few brown dots are situated basally on rhinophores, gills and cerata. All opaque white pattern is lacking. The eyes and spiculae may be observed through the epithelium. DISCUSSION Marcus (1957) published a list of 15 known species of Okenia, and 2 new ones, thus altogether 17 species. Since then, the following species - as far as I know - have been described: Okenia opuntia Baba, 1960: 80; Japan Okenia plana Baba, 1960: 80; Japan Okenia baba: Hamatani, 1961: 117; Japan Okenia angelensis Lance, 1966: 76; north-eastern Pacific Okenia mija Burn, 1967: 55; south-eastern Australia Okenia sapelona Marcus & Marcus, 1967: 203; south-eastern coast of the United States Okenta cupella (Vogel & Schultz, 1970: 390; eastern coast of the United States) (Cargoa Vogel & Schultz, 1970 is a later subjective synonym of Okenia; cf. Burn, 1971 and Opinion 1014, Bull. Zool. Nomencl. 1974) Okenia ascidicola Morse, 1972: 92; Massachusetts The external appearance of Okenia impexa Marcus, 1957 differs clearly from most of the above mentioned spe- cies because of its peculiar cerata, which are swollen and rounded at the tip, narrow at the base, and also because it possesses a single median tubercle on the back. Compar- ably shaped cerata and 1 median appendage are possessed — among the above mentioned 25 species — only by O. plebeia Bergh, 1902 with a rounded lateral tooth and plate-shaped elements on the labial cuticle (BERGH, 1902: pit. III, fig. 17) and O. impexa Marcus, 1957. After the examination of the Mediterranean specimen, Dr. Eveline du Bois-Reymond Marcus confirmed that our animals are O. impexa Marcus, 1957. The shape of the radula, the labial armature and the genital complex correspond in the main features in the animals from the western and from the eastern Atlantic. But there are some differences in the internal anatomy, e. g., in the shape of the lateral tooth, which has 2 cusps in the Mediterranean (Figure 4c), 3 cusps in the western Atlantic specimens. The external habitus also shows differences. In the western Atlantic specimens the median ceras of the notum is club-shaped and is of the same length as the appendages of the notum border. All the specimens from Naples and Banyuls how- ever, have a very short, pointed, finger-shaped tubercle (Figure rb). The lateral posterior appendages of the notum border are apically swollen and rounded in the Mediterranean animals (Figures za, rb), “claviform though pointed” (Marcus, 1957: 434) in the western Atlantic specimens. Because we only know very little about the variability of the species in the western Atlantic (Marcus, 1957, 1961) and in the Mediterranean, we cannot decide whether the mentioned differences are within the normal range of variability of the species or whether they are a manifestation of an independent de- velopment in the western and eastern Atlantic and, thus, whether or not the 2 forms represent 2 geographical sub- species. If further observations in the western Atlantic confirm the constancy of the above mentioned geographi- cal differences, I name the eastern Atlantic subspecies Okenia impexa banyulensts. But as the species was not Page 358 found in Naples or Banyuls prior to 1976, it may be pos- sible that Okenia impexa has only recently entered into the Mediterranean, similarly as, presumably, Doto doerga Marcus & Marcus, 1963 (SCHMEKEL, 1958). Should further research establish that this is indeed a new subspecies, I select the specimen described as the holotype (Figures 1a, 1b) and the dissected specimen as paratype. The holotype has been deposited in the collection of the Naturhistorisches Museum in Basel, Switzerland; the dissected material in the form of micro- scope slides is on deposit at Minster, Germany. Okenia mediterranea (von Ihering, 1886) (Figures 3a, 3b, 3c) Material: Naples: 3 specimens, alive, 3 - 5mm _ long, from Posidonia and other dredged material. Canale di Procida, 20m, 19 August 1963; Bocca piccola, 75m, 12 November 1964; Banco Capo Miseno, 30m, 23 March 1967. Description: Description of a live 4.5mm long animal, found 19 August 1963 on Posidonia, Canale di Procida, 20m. Without measuring the cerata, the flat body (Figure 3) has a length of 4 mm after fixation. The notum has — also without the cerata — its maximum width of 1.6mm im- mediately behind the rhinophores. The maximum height of 1.2mm is found in the region of the pericard in front of the gills. The notum is broader than the foot and is anteriorly and laterally bordered by an approximately 0.5 mm broad free notum margin. Caudally the notum merges without pallial ridge into the weakly keeled tail, measuring about 4 of the body length. The free notum border bears finger-shaped pointed appendages. On each side are situated 8 cerata, the last 2 of which are united at their base. One unpaired ceras is situated medianly behind the gills. The longest, 1 mm long cerata insert in the middle of the anterior pallial ridge; caudally the ap- pendages become continually shorter. In the median line of the notum a low keel-shaped cresta runs from the rhinophores towards the gills. It shows 5 small elevations, but it does not bear tubercles. The rest of the notum is smooth. The smooth anterior border of the foot possesses rounded front angles. Frontally the foot has its maximum width of nearly 1mm, which decreases continuously to- wards the tip of the tail. A bilobed veil is situated over the mouth and underneath the notum border. This veil has large rounded lobes of 1.2 X 0.4mm (Figure 3b) and a median emargination. THE VELIGER Vol. 21; No. 3 The very slender, 1.2mm long rhinophores are situated 0.4mm from the anterior border of the notum. They are smooth in front and laminated with about 23 fine lamel- ‘lae only behind, from the tip almost to the base. Five slender, unipinnate gills, which have a maximum length of 1 mm,are situated medianly at the beginning of last body-third. They insert on a wide, open half-circle in front of the anus. The genital openings are situated at the end of the 1” body-third closely below the right notum ridge. The labial armature consists of a cuticle ring, which is bordered by closely set, low, denticulated papillae on § of its circumference. The radular formula of a 5mm long live animal is 18 X 1:1:0°1°1. The radular rhachis bears no teeth and shows no cuticular support. The 1* lateral tooth is hook-shaped and twiceaslong asthe plate-shaped margin- al tooth. Basis (0.075mm) and tip (0.0o6mm) of the 1” lateral tooth have about the same length and stand in a more or less straight angle towards one another. On the inner border the tip possesses pointed denticles. The mar- ginal tooth with a diameter of 0.03 mm shows a roundish shape with 1 very small hook-shaped cusp. The animal, found 11 December 1964 with a body length of 5 mm while living, was mature, but the preser- vation of the anterior genital complex does not permit a precise reconstruction. The situs corresponds in the main features with the situs of Okenia amoenula Bergh, 1907 (MacnaeE, 1952: fig. 23). There is a well-developed female gland mass, an ampulla, which is tightly filled with sperms and a big, spherical bursa copulatrix. The vas deferens increases to a long prostate tube, which dis- tally decreases into a narrow ductus ejaculatorius, which continues into a tube-shaped penis. The general body colour is whitish, though some regions of the notum appear yellowish or reddish because of the intestine underneath. The right lobe of the veil, but not the left one, shows at its end a big bright yellow spot. A similar spot covers the tip of the tail. All cerata are yel- low from the tip almost to the base, sprinkled with fine clear cadmium-red. The same combination of yellow and clear cadmium-red — which may combine to orange — is to be found on the distal half of the gills and on the median cresta. Dorsally on the right and left side of the notum run 2 irregular stripes of roundish, sometimes very gradually elevated cadmium-red spots towards the tail. Dark cadmium-red spots are also to be observed in the furrow between foot and mantle. The rhinophores are completely opaque-white. Colour and shape variations: An animal of 4.5mm body length when alive, found 12 November 1974, pos- Vol. 21; No. 3 THE VELIGER Page 359 sesses 9 cerata on each side. The last 2 have a common base, on both sides. These last cerata are the longest of all and occupy + of the body-length. There is no unpaired appendage medianly behind the gills. The veil has the same shape as in the animal described above, but bears 2 bright yellow lobes. The rhinophores are opaque-white, as well as the tips of the most anterior and most posterior cerata. All other appendages are cadmium-yellow, the notum cresta is yellow with dark cadmium-yellow spots. The tips of the gills, a median stripe on the tail and round- ish spots dorsally on both sides of the notum are also dark cadmium-yellow. A 3mm long specimen found 23 March 1967 has no cadmium-yellow or red at all, but the whole pattern is pale yellow. DISCUSSION Shape and colour of the species of the genus Okenza are generally so remarkable that many species may be identi- fied by their external appearance. However, as we know nothing about the ecology of most of the species, often only 1 or 2 accidentally dredged specimens are known. To these often questionable species - which have not been found since their original description — belong in the northern Mediterranean: Okenia dautzenbergi Vayssi- ére, 1919 (he himself in 1930 placed it in O. elegans, but Pruvot-Fol kept it as a separate species) and O. medi- terranea. Pruvot-Fo., who believed to have found the latter again (1951: 29), reported (1954: 311), that her unique specimen resembles O. amoenula Bergh, 1907 from South Africa. As we have no details from Pruvot-Fol about the radula, genital organs, veil and cerata, we have to confine ourselves to the few statements given in 1951 and 1954: She states that her unique specimen resembles Okenia elegans very much, though it possesses only one ceras on the notum. Therefore Pruvot-Fol’s specimen probably is neither identical with O. amoenula from the Cap (without a median appendage) nor to von Ihering’s species (with a smooth notum). Unfortunately von Iher- ing’s species entered into literature with the wrong state- ments that it possesses 2 tubercles on each side of the median cresta. von [HERING (1886: 39), however, writes in his description: “Mantel nur am Rande mit Anhangseln.” In describing the pattern he writes: “Zwischen Rhino- phor und Kiemen, letzteren naher, stehen dann jederseits zwischen Mantelrand und Mittelstreif noch 2 gelbe Flek- ken, deren Untergrund in Form eines niederen breiten Hockers erhoben ist. Auch der gelbe Mittelstreif ist etwas wulstig erhoben” (1886: 42). In all the external features our specimens correspond completely with von Ihering’s statements, also in the shape of the teeth and the peculiar shape of the labial hooklets, which are denticulated. Be- sides the smooth notum with a partly elevated cresta, the arrangement and shape of the appendages of the pallial ridge and the large bilobed veil are characteristic for this species. In many external features Okenia mediter- ranea corresponds also with O. amoenula Bergh, 1907 (cf. MacnagE, 1958) from South Africa, to which I erroneously assigned the specimens from Naples (ScHME- KEL, 1968). Okenia amoenula, however, possesses, ac- cording to Bergh’s description, smooth labial hooklets and its pattern differs also in details: O. amoenula has yellowish, O. mediterranea, however, white rhinophores; O. amoenula shows 3 crimson stripes on the notum, O. mediterranea a broad, median line and next to this round- ish spots arranged in 2 lines on each side. The colouration of O. mediterranea, however, may vary considerably. Should differences in the labial armature of both species not be confirmed by new investigations, it has to be ex- amined whether O. amoenula Bergh, 1907 is a synonym of O. mediterranea (von Ihering, 1886), which then has priority. ACKNOWLEDGMENTS The research upon which this paper is based was sup- ported by the Deutsche Forschungsgemeinschaft and the Stiftung Volkswagenwerk. I would like to thank for the use of facilities of the Stazione Zoologica di Napoli and the Laboratoire Arago, Banyuls. I am grateful to Dr. Klaus Bandel, who found, when diving, 2 specimens of Okenia impexa at Banyuls and I wish to thank Miss Ellen Schutt for her valuable assistance. Above all, I am very grateful to Dr. Eveline du Bois-Reymond Marcus for the critical reading of the German manuscript. Literature Cited Baza, Kixutar6 1960. The genera Okenia, Goniodoridella and Gontodoris from Japan (Nudibranchia-Goniodorididae). Publ. Seto Mar. Biol. Lab. VIII (1): 79 - 83 Berou, Lupwic SopHus Rupo.F 1881. Uber die Gattung Idalia Leuckart. (1): 140-181 1902. The Danish Expedition to Siam 1899-1900. I. Gasteropoda opisthobranchiata. Kgl. Danske Vidensk. Selsk. Skrift 6 (2): 155 Arch. £ Naturgesch. 47 to 218 1907. Marine investigations in South Africa. Trans. So. African Phil. Soc. 17 (1): 1-144 Burn, Robert , 1967. Descriptions of two new species of Okenia (Nudibranchia, Dori- dacea) from south-eastern Australia. Proc. Roy. Zool. Soc. N.S. W. ae 2 Comment on the proposed addition to the official list of Okenia Menke, 1830 and Idaliella Bergh, 1881. Bull. zool. No- mencl. 28: 141 Page 360 Hamatani, Iwao 1961. Preliminary account of a new species of Okenta from Osaka Bay, Japan (Nudibranchia-Goniodorididae). Publ. Seto Mar. Biol. Lab. IX (2): 363 - 365 IHeERING, H. von 1886. Beitrage zur Kenntnis der Nudibranchien des Mittelmeeres. IT. 4. Die Polyceraden. Malakozool. Blatt., N. F 8: 12-48 Lance, James RoBert 1966. New distributional records of some northeastern Pacific Opistho- branchiata (Mollusca : Gastropoda) with descriptions of two new species. The Veliger 9 (1): 69-81; 12 text figs. (1 July 1966) LgMcHE, HENNING 1971. Okenia Menke, 1830, and IJdaliella Bergh, 1881 (Mollusca, Opisthobranchia): proposed addition to the official list. Bull. zool. Nomencl. 27 (5/6): 265 - 266 Macnag, WILLIAM 1958. The families Polyceridae and Goniodorididae (Mollusca, Nudi- branchiata) in Southern Africa. Trans. Roy. Soc. So. Africa 35 (4): 341 - 373 Marcus, ERNST 1957. On Opisthobranchia from Brazil (2). 390 - 486 1961. Opisthobranchia from North Carolina. 77: (2): 141-151 Journ. Linn. Soc. 43: Journ. Mitchell Soc. THE VELIGER Vol. 21; No. 3 Marcus E. « E. Marcus 1967. Some opisthobranchs from Sapelo Island, Georgia, U.S.A. Malacologia 6 (1-2): 199-222 (31 December 1967) Morse, M. Patricia 1972. Biology of Okenia ascidicola spec. nov. (Gastropoda : Nudi- branchia). The Veliger 15 (2): 97-101; 5 text figs. (1 Oct. ’72) Pruvot-For, Aticz 1951. Etude des nudibranches de la Méditerranée. exp. gén. 88: 1 - 80 1954. Mollusques opisthobranches. ScHMEKEL, Luise RENATE 1968. Doto doerga Marcus, 1963 (Gastr. Nudibranchia) aus dem a Meer im Golf von Neapel. Pubbl. Staz. Zool. Napoli 30: 1-7 VayssizrE, ALBERT JEAN BAPTISTE MaRIz 1919. Recherches zoologiques et anatomiques sur Jes mollusques opistho- branches du Golfe de Marseille. Ann. Mus. Hist. Nat. Marseille 17: 53-92 1930. Mollusca Arch. Zool. Faune de France 58: 1 - 460 in: Faune et flore de la Méditerranée. Comm. Internat. Explor. Sci. Mer Méditerranée, Paris. VoceL, Rosarie M. & Leonarp P. ScHuULTz 1970. Cargoa cupella, new genus and new species of nudibranch from Chesapeake Bay and the generic status of Okenia Menke, Idalia Leuckart, and IJdalla @rsted. text figs. The Veliger 12 (4): 388-393; 5 (1 April 1970) Vol. 21; No. 3 THE VELIGER Page 361 Malagarion paenelimax gen. nov., spec. nov., A New Slug-like Helicarionid from Madagascar (Pulmonata : Helicarionidae ) SIMON TILLIER Laboratoire de Biologie des Invertébrés Marins et de Malacologie Muséum National d’Histoire Naturelle, 55, Rue Buffon, F 75005 Paris, France (8 Text figures) INTRODUCTION Since 1949, Pr E. FiscH—ER HAS BEEN forming a collec- tion of land snails from Madagascar in the MNHN. This collection now amounts to more than 10000 lots and is probably the most important in the world for this region; Pr Fischer published more than 30 papers dealing with this material between 1949 and 1977. Most of the materi- al consists of dried shells, but in the small suite of speci- mens preserved in liquid was found the new Helicarionid here described, which was given by Mrs. F Blanc who collected it during the 1972 CNRS-RCP 225 expedition in the Marojezy Mountains in the northeast of Madagas- car. Malagarion Tillier, gen. nov. Diagnosis: A helicarionid with a much reduced shell (less than 2 whorls and almost completely uncalcified) completely covered by the mantle which has no distinct lobes; visceral cavity not entering the posterior part of the foot which is depressed by the visceral hump lying on it. Genital apparatus without a sarcobelum; penis with a penial sheath joining the epiphallus, a flagellum and a short retractor caecum on the outer side of the angle be- tween penis and epiphallus; lower part of the free ovi- duct inflated and isolated from the upper part by a papilla; vagina and atrium much reduced. Radula with teeth small, very numerous and close-set; the central uni- cuspid, a few laterals tricuspid and the marginals very numerous (about 300 per half row) and bicuspid. Type Species: Malagarion paenelimax Tillier, spec. nov. Malagarion paenelimax Tillier, spec. nov. Material: The holotype. Type Locality: Marojezy Mountains, 600m; 12 De- cember 1972; F Blanc coll. et leg. MNHN. External Morphology: (Figure 1) Animal 28mm long in alcohol with a tail 17 mm long and a narrow foot (2.5 mm wide). The visceral hump, completely covered by the mantle without any pore, lies in a triangular depres- sion on the anterior part of the tail (on the holotype this depression is probably accentuated by the position of the animal). The mantle forms a nuchal shield extending forward about halfway to the ocular tentacles. The tail is truncated, without prominent horn, split by the caudal gland which is about as deep as high and triangular in vertical section. The pedal sole is tripartite and limited by a lateral pedal groove. The tegument of the foot is reticu- lated, with nuchal grooves hardly visible; the reticula- tion is interrupted above the pedal groove and at a short distance from the truncated posterior end. The mantle is covered with granules which become larger and conical on the back of the visceral hump. The colour in liquid is whitish with the upper part of the mantle and tail finely punctulated with pink, and the nuchal region creamy. Internal Morphology: The shell has about 1.5 whorls. It is reduced to a horny membrane, except in its last 0.5 whorl where it is slightly calcified with thin concentric growth lines. It is impossible to remove it without break- ing either the periostracum or the mantle edge. The Body Cavity (Figure 2) does not extend at all into the posterior part of the foot. The oesophagus and Page 362 THE VELIGER Vol. 21; No. 3 Figure 1 Malagarion paenelimax Tillier, gen. nov., spec. nov. Habitus of the holotype the enlarged crop lie on the left side, partially embedded in the folds of the oviduct which lies on the right side together with the penis and the bursa copulatrix. The stomach and intestine make 3 loops in the visceral mass, which contains the albumen gland in its concavity and the ovotestis at its extremity. The free Retractors have 3 insertions along the ligamental back edge of the body cavity; from left to right: -The left tentacular retractor crosses over the crop and then lies along the left side of the anterior digestive tract; -The buccal retractors have a large common stem which divides into 2 branches passing through the nerve ring and inserting below the buccal mass; -The right tentacular retractor runs between the anterior digestive tract and the genital apparatus; it lies on the left side of the latter for its entire length. (scale: 1mm) The Pallial Complex (Figures 3 and 4) occupies the left anterior half of the visceral hump; kidney, heart and rectum are parallel in a diagonal direction, from the left posteriorly to the right anteriorly. The kidney, very long, is posteriorly reflected into a lobe itself folded in such a way that it is applied to the pericardium on one side and to the second loop of the intestine on the other. The ure- ter, about of the same diameter as the intestine, overlaps the direct lobe of the kidney before turning back along the rectum; the latter is inflated just anterior to the anus. The external opening is an oblique slit which is divided by a vertical pillar into posterior anus and anterior upper pneumostome and lower kidney pore. Genital Apparatus: (Figures 5, 6, 7) The small ovo- testis is subspherical, blackish and formed by numerous acini. The hermaphrodite duct, rather short, becomes Vol. 21; No. 3 Figure 2 Malagarion paenelimax Tillier, gen. nov., spec. nov. Disposition of the digestive tract and of the free retractors (rhinophoral branches of the tentacular retractors not depicted) broader and twisted in its distal part. It opens into the spermoviduct at the base of a short and broad talon ap- plied on the concave side of the albumen gland. The spermoviduct is subcircular in section in its first half, but in its second half the oviduct forms large flat expansions in which the anterior digestive tract is partially embedded in situ. The free oviduct is divided into 3 sections: the first THE VELIGER Page 363 Figure 3 Malagarion paenelimax Tillier, gen. nov., spec. nov. Disposition of the organs in the visceral hump, upper view AG - albumen gland DG - digestive gland H — heart I — Intestine K — kidney KD - Kidney duct (scale: 1 mm) has a thick orange wall and is probably glandular; the second is a simple tube which opens by a prominent con- stricted papilla into the third. The latter, which may be involved either in the secretion of the shells of the eggs or, by analogy with Colparion, in their incubation, is a greyish, thick walled and curved pouch and has a large and internally folded opening at the base of the bursa Page 364 THE VELIGER Vol. 21; No. 3 KD Figure 4 Malagarion paenelimax Tillier, gen. nov., spec. nov. Pallial complex, lower view KD - kidney duct P — pericardium H — heart K - kidney R - rectum (scale: 1 mm) copulatrix. Except for these few folds and the papilla, the inner wall of the oviduct is smooth. The bursa copulatrix is rather short and finger-like. Its inner wall is smooth in its inferior third, and has trans- verse regular folds in its upper two thirds. The oviduct and the bursa copulatrix open without a distinct vagina into the genital atrium, which is reduced as much as possible and internally smooth. The penial complex (Figures 6 and 7) has a sheath, a short retractor caecum inserted on the outer side of the angle between penis and epiphallus, and a flagellum. The epiphallus and flagellum are bent back along the penis, the former being connected to the penial sheath by a tract. The penis is divided into 2 subequal parts by a penial pa- pilla. Just above and below this papilla the penis is in- flated and internally granulous whereas it is tubular with internal longitudinal folds in its lower and upper parts. Just below the penial papilla a second papilla is inserted; it is folded and triangular when flattened. The penis has 2 sheaths: the lower one, thicker and with circular fibres in its lower part, encloses the lower tubular part of the penis and is joined to the epiphallus by a thin connective tract; the upper penial sheath is much thicker and en- closes only the upper bulbous part of the penis. The cae- cum prolongs the penis and is bent along the epiphallus; it is short, not coiled, thin walled and has internal longi- Vol. 21; No. 3 THE VELIGER Figure 5 Malagarion paenelimax Tillier, gen. nov., spec. nov. Genital apparatus: copulatrix C - caecum HD - hermaphrodite duct free oviduct Pe — penis tudinal folds, except in its basal region where the folds are honeycomb-like. The epiphallus opens into the penis at the base of the caecum by a narrow and prominent pa- pilla. Its inner wall is also longitudinally folded except around the opening of the vas deferens where it is smooth. It is bent in its thin sheath which adheres to its wall at the convexity of the bends. The flagellum is a hollow tube, internally smooth, with its axial cavity occluded by a rod which is cylindrical near its fixed extremity and then flat- tened with its free end enlarged; such a structure was pre- viously described by vAN Mot (1968, 1970). The ex- tremity of the flagellum is bent back, with a thin sheath visible in the convexity of the bend. No horny spermatophore was found, but the bursa co- pulatrix was filled with whitish, soft fragments; on the other hand, the epiphallus contained a mass of the same AG - albumen gland E — epiphallus OI, OII, OIII —- sections of the SO - spermoviduct (scale: 1 mm) BC — bursa F — flagellum material which disintegrated when dissected. This sug- gests, but does not prove, the occurrence of a soft sperma- tophore; if a horny spermatophore is found later on, it will probably be smooth as a result of the absence of crypts in the inner wall of the flagellum. The Radula (Figure 8) is formed by 132 V-shaped rows, with an angle of about 130°, and more than 600 teeth per row; formula: (g3o0+15) - (3-6) -C: (3-6) : (300415). All the teeth have very long basal plates, nearly extending to the extremity of the cusps and parallel to the upper plates. The central is unicuspid, elongated, about 30 um long. The lateromarginals are elongated too, very tight and slightly sigmoid, becoming progressively smaller when approaching the end of the rows. The first ones are tri- Vol. 21; No. 3 ee Som" 2o 8 & AS ! & » a OPO ak Sms —s S mos & e aa 8 ee > yo A} a — i | la 4 - 2 sg O ® Sey 35 — a ey Oe —I ©) 5.8, uu eg 8 ss 5 eF > 2 fae a) % 2 o | Li; s & Ce ie & 2926 | | cas J’ Se : A ES S AN Ea WS Tes v ° y, os Qs Mis & 8 a 5 5 4 » a aye 4 Maa . ey Gro) oO) en \ § 2° 2 ee \ E = \ Yad Ya8 NS SSS HoH SS : ee eee COO AARNARI SB a Be XW. 0 \ YS N SE ANRAAN =a! & fad SN — a if [DurHAM] Figures g to 17 Tue VELicER, Vol. 21, No. 3 Vol. 21; No. 3 of the outer shell layers, with the projection from the adapical side overlapping that from the adoral side. Ex- amination of several other species of Haliotis shows a similar mode of formation of their tremata. Occurrence: Fifteen specimens examined are from the Galapagos Islands, from intertidal to depths of about 110 m. They are from LACM localities 30142, 30143, 30144, 66-210, 72-197, AHF 147-34, AHF 148-34, and AHF 198- 34. Most specimens are from depths around 60m, but the largest (Figure 2) is from the intertidal zone. Two speci- mens (LACM loc. AHF 81-38) are from north of Gor- gona Island, Colombia, depth between 18 and 36m. Haliotis (Padollus) roberti McLean, 1970 (Figures 8, 9, 12) Haliotis (Padollus) roberti McLEaANn, 1970: figs. 1-2; — KEEN, 1971: 309, 311 (fig. 2); — ABBOTT, 1974: 18, 19; fig. 33 Nine specimens, including the holotype and 2 para- types of this species from Cocos Island have been avail- able, but 3 of them are very small and worn. The spiral ridge characteristic of Padollus is well developed only on specimens from locality LACM 73-176. At similar sizes there are fewer and heavier spiral cords above the tremata and on the periphery below them than on Haliotzs dalli. Further, the body whorl is more inflated than on the Gala- pagos species. However, there are more spiral cords than on the new fossil species. The measurements (made in the same manner as for H. dalli) of the holotype (Figures 8, 12) are: major diameter 18.6mm; height 6.6mm; total height (axis of coiling vertical) about 12.5 mm. Occurrence: Known from Chatham Bay, Cocos Island, Costa Rica, between 73 and 86m in depth and nearby Isla Manuelita at depths of 146 and 174m (LACM locs. 73-116 and 73-117). Haliotis (Padollus ?) santacruzensis Durham, spec. nov. (Figures 6, 7) Described on the basis of a single incomplete specimen (original major diameter about 12mm) with aperture filled with matrix. Shell profile similar to that of Haliotis dalli and not inflated like H. roberti; a distinct concave area below trematal angulation; spiral cording suggestive of H. pourtalesii Dall, 1881 as illustrated by Aspott (1974: 18, fig. 30), but cords less numerous at similar THE VELIGER Page 371 sizes; at a diameter just under 10 mm (see Figure 6) there are g or 10 major cords above the tremata and 4 in the concave area (see Figure 7) below the tremata; the sub- trematal area is very similar to that of Abbott’s figure; the spacing of the tremata seems to be about the same as on a similar sized specimen of H. voberti (Figure g) ; al- though not well preserved, there appear to be 3 or 4 spiral cords on the oral surface below the lowermost peri- pheral whorl angulation (see Figure 7), much like those on H. dalli (see Figure 5). Holotype: UCMP 145809, loc. B-3612, near Cerro Colo- rado, northeast of Academy Bay, Santa Cruz Island, Gal- apagos Islands. Age: Late Miocene (DURHAM & McBirneEy, 1975: 286 to 287) Discussion: This species differs from Haliotis barbad- ensis Trechmann, 1937, H. dall: Henderson, H. roberti McLean, and H. pourtalesi Dall by the fewer cords above the tremata at similar sizes; the upper whorl profile is not as inflated as in H. roberti or H. pourtalesu (judging from AsgottT, 1974: 18, fig. 30). The elevated ridge and corresponding internal groove above the row of tremata that is characteristic of most specimens of this group of species is not clearly evident on this specimen, but in view of its general similarity to H. dali, H. pourtalesu, and H. roberti it is tentatively referred to Padollus, the subgenus to which these species have mostly been referred. The 4 (H. pourtalesi, H. dalli, H. barbadensis and H. roberti) appear to be closely related and it is probable that H. santacruzensis spec. nov. represents the parental stock that was living in the tropical eastern Pacific-Caribbean region before the Late Tertiary division of the area by the formation of the Central American landmass and the filling of the northwest Colombian trough. JuNc (1968), without discussion, referred both Hali- otis pourtalesin and H. barbadensis to the subgenus Sulcu- lus, rather than to Padollus, as previous authors had done. The type of Sulculus is H. incisa Reeve, 1846, which as illustrated in Conchologica Iconica has the apex nearly marginal and a rapidly expanding body whorl, unlike the species discussed above. It is improbable that they should be assigned to Sulculus. Haliotis pourtalesii was referred to Padollus by Datt (1881; 1890) and HENDERSON (1915). Although the critical ridge is not apparent in the inadequate illustrations of Foster (1946), GuicE (1968) and AspotT (1974), those of Harry (1966) and JuNnc (1968: figs. 7-9) confirm its presence. The Caribbean and Eastern Pacific species discussed herein have less ec- centric apical whorls than in Sulculus and a closely coiled body whorl, like those of the type of Padollus. The raised Page 372 THE VELIGER Vol. 21; No. 3 ridge (and corresponding internal groove) adapical to the tremata is not as strongly developed as in typical Padollus, but in view of its presence, these species are best assigned to this subgenus. Trechmann’s species was referred to the late Pliocene by Jung, but the “Coral-rock” in which it is found is currently referred to the Pleistocene. If the Galapagos species is correctly referred to Padollus, it extends the range of Padollus back to the Miocene. This is the second (‘Irechmann’s species was the first) fossil Haliotis to be described from the tropical region of the Americas and adjacent islands, although Cretaceous (ANDERSON, 1902), Miocene (WoopRING, 1931; 1932; HERTLEIN, 1937) and Pliocene (VoKEs, 1935) species have been described from California. Literature Cited [see combined list at end of following paper (DuRHAM, California’s Cretaceous Halizotis) ] Vol. 21; No. 3 THE VELIGER Page 373 California Cretaceous Haliotis J. WYATT DURHAM Department of Paleontology, University of California, Berkeley, California 94720 (with part of 1 Plate) AT THE BEGINNING of this century, F M. ANDERSON (1902: 75; plt. 9, fig. 183) described a small fossil Hali- otis from the Upper Cretaceous of Point Loma, near San Diego, California. The specimen, associated with Pecten californicus and Acteonina pupoides, had been collected by H. W. Fairbanks from “...below the beds con- tain[ing?] Coralliochama orcutti according to the state- ments of Dr. Fairbanks.” It was illustrated by a crude pencil drawing (repeated in ANDERSON, 1958: plt. 21, fig. 12). Although ANDERSON in his original description (1902: 75) noted its resemblance to Haluotis iris, the systematic position of the specimen has been doubted. Wooprinc (1931: 35) was sceptical of its generic assign- ment and Cox (in Moore, 1960: 221 - 222) noted that it and other putative Cretaceous haliotids needed to be be confirmed. VoKES (1935: 251), after examination of the holotype, affirmed that it was a true Haliotis, as did HERTLEIN (1937). I have examined the specimen and because it has never been adequately illustrated and clearly is similar to H. zris as stated by Anderson, I am illustrating it photographically. The specimen is now in the type collection (no. 69) of the Department of Geology of the California Academy of Sciences (CAS), San Francisco. It is in 2 parts, imbedded in a fossiliferous hard, dark gray-green gritty fine sand- stone. The associated fossils include fragments of a small oyster, calcareous algae, an echinoid spine, a cross sec- tion of a gastropod, a serpulid tube, an external mold of a small fragment of a heteromorph ammonite, and a fragment of a pelecypod. Anderson reported that it came from below the Coralliochama horizon at Point Loma. The lithology of the matrix suggests that the specimen came from the Kr(b) member (above basal redbeds) of the Rosario Formation as shown in the columnar section of Mrrow « Ennis (1961: 26 and 36, Stop #10). PopEeNnoE, IMLay & Murpuy (1960) assigned the Rosario Formation at Point Loma to the Lower Maestrichtian, although they implied that there is some uncertainty as to whether the formation extends down into the Campan- ian. Thus, it is probable that Anderson’s species is of early Maestrichtian age but it might possibly be of latest Campanian age. It is clear that Haliotis was present in the late Cretaceous of California. The type specimen is very similar to small specimens of Halotis iris Martyn, 1784, the type species of the sub- genus Paua Fleming, 1952, so H. lomaensis is assigned to this subgenus. This paper has benefitted from discussions with Carole S. Hickman and Joseph H. Peck, Jr. SYSTEMATICS Halotis Linnaeus, 1758 Type species: Haliotis asinina Linnaeus, 1758 The shell of Haliotis asinina is very elongate and nar- row, with the apex very eccentric. Very few species are similar to it and assignable to the typical subgenus. In the Treatise on Invertebrate Paleontology (Moore, 1960) 11 subgenera are recognized. FLEMING (1952) reviewed some of these when he proposed the subgenus Paua. (Paua) Fleming, 1952 Type species: Haliotis iris Martyn, 1784 (figured herein, Figures 13, 16, 17) Shell of few whorls, last whorl rising above apex; outer lip extending around behind apex for about a half volu- tion (see Figure 16) and overlapping the columellar flange (in Fleming’s diagnosis, the terminology is con- fusing), which forms a broad posterior labral area; a slight angulation at the row of tremata; mature shells with adductor scar deeply incised but not apparent on small shells; posterior labral area forms posterior shell margin; ornamentation collabral and sometimes with faint oblique undulations and inconspicuous spiral cords. According to the Treatise on Invertebrate Paleontology (Moore, 1960: I223) Paua has a range of Miocene to Recent in New Zealand and Japan; the assignment of Haliotis lomaensis to the subgenus extends it back to the late Cretaceous. This suggests that Pawa may be near Page 374 THE VELIGER Vol. 21; No. 3 the ancestral stock of the haliotids, but it is highly spe- cialized in the greatly enlarged body whorl. The types of the 2 other reputed Cretaceous haliotids, H. antiqua Binkhorst, 1861, and H. cretacea Lundgren, 1894, need to be restudied. Haliotis (Paua) lomaensis Anderson, 1902 (Figures 14, 15) Haliotis lomaensis ANDERSON, 1902: 75; plt. 9, fig. 183; - WoonprING, 1931: 34-35; — VOKES, 1935: 251 — AN- DERSON, 1958: 146; plt. 21. fig. 12 (reprint of 1902 drawing) Shell small, length 13mm, width 9.6mm, outermost surface poorly preserved, but most of shell present; apex very eccentric, with at least one volution (very similar to Haliotis iris, compare Figures 13 and 15) ; last 4 tremata open and at least 2 earlier ones closed; shell profile with slight angulation along row of tremata; outer lip extends well around spire (see Figure 15) overlapping columellar flange as in H. iris; posterior labral area forms shell mar- gin; microstructure of shell where observable suggests that there may have been inconspicuous spiral cords. The shell is somewhat recrystallized and the nacreous character of the inner layers lost although in some areas the laminated character of the original nacre is still ap- parent. Anderson’s original drawing suggests the presence of a ridge just adapical to the row of tremata — this part of his drawing is based on the internal mold of this area of the shell and actually represents a low ridge on the interior (not exterior) of the shell just adapical to the tremata. None of the specimens of the Recent Halzotis iris that have been examined have this structure. No evi- dence of a strongly impressed adductor muscle scar can be recognized on Anderson’s type, but the internal surface of the shell is not well preserved in the area where it would be expected. The very eccentric small apex, outer lip extending around posterior to apex and merging with columellar flange, and the combined flattened columellar flange — outer lip forming the posterior margin of the shell indicate that this species should be assigned to the subgenus Paua. Literature Cited (Combined list for this and the preceding paper by DurHam) Assott, Ropert TUCKER 1974. American seashells. Nostrand Reinhold, New York ANDERSON, FRANK MARION 1902. Cretaceous deposits of the Pacific coast. Sci. (3) 2: 1-154; 12 plts. 1958. Upper Cretaceous of the Pacific coast. Mem. 71: 379 pp.; 75 plts. and ed., 663 pp.; 24 col. plts. Van Proc. Calif. Acad. Geol. Soc. Amer. Dati, WituiaM HEALEY 1881. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico, and in the Caribbean Sea, 1877-79, by the United States Coast Survey Steamer “Blake,” XV, Preliminary report on the Mollusca. Bull. Mus. Comp. Zool. 9 (2): 33-144 (July-December 1881) 1889. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Car- ibbean sea (1879-80), by the U.S. Coast Survey Steamer “Blake,” ... XXIX. Report on the Mollusca.—Part II. Gastropoda and Scaph- opoda. Bull. Mus. Comp. Zool. Harvard 18: 1-492; plts. 10-40 (January - June 1889) 1890. Scientific results of explorations by the U.S. Fish Commission Steamer Albatross. No. VII.—Preliminary report on the collection of Mollusca and Brachiopoda. Proc. U.S. Nat. Mus. 12 (773): 219 - 362; plts. 5-14 (7 March 1890) DurHam, JoHn Wyatt 1965. Geology of the Galapagos. Pacif. Discov. 18: 3-6 Duraam, JoHN Wyatr #& ALEXANDER R. McBirnzy Galapagos Islands. In: Rhodes W. Fairbridge (ed.), The en- cyclopedia of world regional geology, Part 1: 285-290 (Dowden, Hutchinson and Ross, Inc.. Stroudsburg, Penn.) FLEMING, CHar-es A. 1952. Note on the genus Haltotis (Mollusca). A new subgenus from New Zealand and a new species from the late Cenozoic of Ohope, Bay of Plenty. Trans. Roy. Soc. New Zeal. 80 (2): 229-232; plt. 50 Foster, RicHARD WINSLOW 1946. The family Haliotidae in the western Atlantic. 2 (21): 37-40; plts. 22- 23 Guice, Cuarzes J. 1966. Haliotis pourtalesii Dall, 1881, from Florida waters. The Veliger 11 (2): 140; plt. 18 (1 October 1968) Harry, Harotp WILLIAM 1966. Haliotis pourtalesii Dall, 1881, from Yucatan. 8 (4): 207-208; plt. 30 HeNnDERSON, JOHN B. 1915. Rediscovery of Pourtales’ Haliotts. 48: 659 - 661; plts. 45, 46 HerTLeEIN, Lzo Gzoror 1937. Haltotis kotickt, a new species from the Lower Miocene of Cali- fornia. Bull. South. Calif. Acad. Sci. 36: 93-96; plt. 42 Juno, PETER 1968. Pleurotomaria and Haliotts from Barbados and Carriacou, West Indies. Eclog. geol. Helv. 61: 593 - 605 Keen, A. Myra, with the assistance of James HamILTON McLEAN 1971. Sea shells of tropical West America: marine mollusks from Baja California to Peru. 2"d ed. Stanford Univ. Press, Stanford, Calif. i- xiv+1064 pp.; ca. 4000 text figs.; 22 col. plts. (21 September 1971) McLegan, James HaMILTON 1970. New species of tropical eastern Pacific Gastropoda. Malac. Rev. 2: 115 - 130 (8 May 1970) MiLow, E. Dean & Davp B. ENNIS 1961. Guide to geologic field trip of southwestern San Diego County. Guidebook for Field Trips, 572 Ann. Meetg., Cordilleran Sect., Geol. Soc. Amer., pp. 23 - 43 Moore, Raymonp C. (Editor) 1960. Treatise on invertebrate paleontology, Part I, Mollusca I. 351 pp. Univ. Kansas Press and Geol. Soc. Amer. Pirssry, Henry AvuousTus 1890. Manual of Conchology; (1) 12: 323 pp., 65 plts. Porenog, Wits P, RatpH W. ImMvtay & MicHageLt A. MurPHY 1960. Correlation of the Cretaceous Formations of the Pacific coast (United States and northwestern Mexico). Bull. Geol. Soc. Amer. 71: 1491 - 1540 Stearns, Ropert Epwarps CARTER 1893. Report on the mollusk-fauna of the Galapagos Islands, with descriptions of new species. Proc. U. S. Nat. Mus. 16 (942): 353 to 450; plts. 51, 52 TrecHMANN, C. T. 1937. The base and the top of the Coral-rock in Barbados. Geol. Mag. 74: 337-359; pit. 12 Voxes, Harotp ERNEST 1935- A new species of Haliotis from the Pliocene of southern Cali- Johnsonia The Veliger (1 April 1966) Proc. U.S. Nat. Mus. fornia. Journ. Paleontol. 9: 251 - 252; pit. 25 Wooprinc, WENDELL PHILLIPS 1931. A Miocene Haliotis from southern California. Journ. Pale- ontol. 5: 34 - 39; plt. 6 1932. A Miocene mollusk of the genus Haliotis from the Temblor Range, California. Proc. U. S. Nat. Mus. 82 (art. 15): 1-4; pit. 1 Vol. 21; No. 3 THE VELIGER Page 3 | or Chlamydoconcha orcutt: Dall: Review and Distribution of a Little-Known Bivalve BY JAMES T. CARLTON Department of Geology, University of California, Davis, California 95616 THE INTERNALLY-SHELLED epifaunal veneroid clam Chlamydoconcha orcutti was named as a new genus and species by William Healey Dat in 1884 based upon spe- cimens collected by Charles R. Orcutt in Mission Bay (formerly False Bay), San Diego County, California. It is doubtful if any semblance of the exact locality within Mission Bay that Orcutt visited still exists (see, for ex- ample: OrctTT, 1919: 64; MorRISON, 1952, 1954, 1957; CuapMan. 1963). This note brings together an obscure and scattered literature, summarizes available ecological data, documents further localities, corrects a recent litera- ture statement concerning Chlamydoconcha, and estab- lishes type material. The range is extended north to Shell Beach, Sonoma County, California (38°25’20”N; 128° 07’00”W) and south to Punta San Pablo, on the Pacific coast of Baja California Norte (27° 12’30”N; 114°28'50” W). The family Chlamydoconchidae, erected by Dat (1884, as the family “Chlamydoconchae”’; not 1889 (AsBBOTT, 1974) and not 1899 (KEEN, 1969), in which Chlamjdo- concha is placed, has been used by most American workers (KEEP, 1994, as Chlamydochonchidae; OLpRoyD, 1925; Keep & Batty, 1935; BurcH, 1944; SMITH & GoRDON, 1948; KEEN, 1969; KEEN & Coan, 1974; ABBOTT, 1974). THIELE (1934) regarded it as a subfamily (Chlamydo- conchinae) of the Erycinidae, perhaps influenced by the remarks of FiscHER (1887a, 1887b) and BERNaRD (18972, 1897b). GottiING (1974) placed Chlamydoconcha in the Leptonidae. Its placement in the Erycinidae or Leptoni- dae, however, is incompatible with current diagnoses of either family (see CHavan, 1969; KEEN, 1971). KEEN (1969) erected the superfamily Chlamydoconchacea, re- moving Chlamydoconcha from its placement in the Ery- cinacea (Leptonacea) (Dat, 1921; THIELE, 1934; KEEN, 1963; VoKES, 1967). ' ' The chiton genus Chlamydoconcha Pilsbry, 1893, a junior homo- nym, is a synonym of Amicula Gray, 1847 (SmiTH, 1960). Studies on Chlamydoconcha have concerned its ana- tomy (Dati, 1884; FiscHer, 1887a; BERNARD, 18974, 1897b), with brief remarks existing on its distribution and natural history (WILLIAMS, 1949; TURNER & EBERT, 1962; TURNER, EBERT & GIVEN, 1969), and diet (“‘plankton,” JoHNSON, 1953; “bacteria,” TURNER & EBERT, 1962). Mentions by Dat, 1899, 1916; KELSEY, 1907; OLpD- ROYD, 1925, and Orcutt, 1885, 1900 and 1915), cited occasionally in reference to Chlamydoconcha, are listings only, with no new information. Table 1 summarizes the localities where Chlamydo- concha has been found. North of Point Conception, C. orcutti is known only from Sonoma and Monterey Coun- ties. Previous Monterey records are old and few, without detailed information. In 1915, Orcutt reported that, “A single specimen of this curious clam ... is reported from Monterey bay, California.” In 1919, OrcuTT wrote a- gain ““... since reported from Monterey Bay by Dr. [S. Sullman] Berry.” The source of Berry’s record, if first published by other than Orcutt (as Orcutt’s wording would appear to imply), has not been located; Chlamy- doconcha does not appear in Berry’s checklist of Monterey Bay mollusks (BERRY, 1907, 1908). Whether Datt’s (1921) citation is a repeat of Orcutt’s listing cannot now be known. A second (or third) report from Monterey was that of Harold Heath of Hopkins Marine Station, of unknown date (SMITH & Gorpon, 1948). A single specimen recovered subtidally at Shell Beach, Sonoma County, in 1969 by a University of California at Berkeley zoology student was brought to the Bodega Ma- rine Laboratory and examined by Dr. Cadet H. Hand, myself, and others. Unfortunately, the specimen was not retained. Chlamydoconcha has been found from the littoral zone to a depth of 38m, often clinging to and crawling upon the undersides of rocks. It may be restricted further in some areas to rock substrates over detritus-rich mud and sand bottoms (BERNARD, 1897b; TURNER & EBERT, 1963). Page 376 THE VELIGER Vol. 21; No. 3 ee ee ee eee rere eer eee errr eee eee re Table 1 Records of Chlamvdoconcha orcuttt Locality (Date. Collector) Habitat CALIFORNIA Sonoma Co.: Shell Beach State Park. 11.7 km north of Bodega Bay (17-V-1969) Monterey Co.: Monterey Bay Monterey Co.: “Monterey” Monterey Co.: Monterey Bay: Pacific Grove Monterey Co.: Monterey Bay: Pacific Grove: Chase Reef (VIII.1971. A. J. Ferreira) Monterey Co.: Monterey Bay: off Monterey (6.VIII.1970, A. J. Ferreira) Monterey Co.: Carmel Submarine Canyon Santa Barbara Co.: Santa Barbara Santa Barbara Co.: Hope Ranch Beach (10.X1.1967. S. Spaulding) Channel Islands: Santa Cruz. Anacapa. Santa Catalina. and San Clemente Los Angeles Co.: Santa Monica Bay Orange Co.: Newport Bay (1929. Lowe: others, no date) San Diego Co.: La Jolla: Bird Rock (16.VIII.1927. P. Barnhart) San Diego Co.: San Diego: Point Medanos (near entrance to Mission Bay) (1.1948. W. Williams) San Diego Co.: San Diego: Mission Bay (False Bay) San Diego Co.: off Imperial Beach (9.X.1946. E. W. Scripps. Kenyon. Williams) BAJA CALIFORNIA NORTE, MEXICO Isla Cedros Island (ca. 1930s) Punta San Pablo (25.X.1971, R. V. Searcher, J. H. McLean, P. LaFollette) sublittoral. about 9m? intertidal, on rocks under rock. 15 m under rock. about 30 m on rocks. about 24 m kelp holdfast under rocks. 3 to 38 m at Santa Catalina crawling on rock under- sides and stones in detritus-rich sandy-mud areas: to 18.3 m:7 to 10 specimens under a single small flat rock on the shore. anchored by a byssus to under sides of stones: on a muddy, stony bank and stony clam bed: under rocks dredged on kelp: rocky bottom with heavy algal growth rocky pinnacles off point. sand base. strong surface current, 21-30 m Authority. Depository specimen examined at Bodega Marine Laboratory (not preserved) Orcutt. 1915a, 1919 Da tt. 1921 HeaTH. tn SmitH & Gorpon. 1948; notes by Allyn G. Smith CASIZ MLML (no. 110013) J. H. McLean (in fitt) JoHson. 1953: TURNER. Epert. & GIVEN, 1969 SBMNH (no. 25073) Turner & Epert. 1962: TURNER. EBERT. & GIVEN. 1969 TuRNER & EBerT, 1962; TURNER. EBERT. & GIVEN. 1969: UCMP: LACM: USNM (no. 576192) E. M. & E. P. CHace: M. CaruTtuers: H. Lowe. all in Burcu. 1944 Williams. 1949: CASIZ (no. G-32760) CASIZ (no. G-32759) Dall. 1884: Orcutt. 1885: Bernard. 1897b: Orcutt. 1915a: the Chaces, in Burch, 1944; Johnson, 1945: Williams, 1949; USNM (nos. 107222-107234: 738567- 758568); CASIZ (no. G-32761; 27.1X.1946. W. Williams) Witirams, 1949: CASIZ (no. G-32758) Walter Everdam collection (Frank Bernard, in itt.) LACM (no. 71-178) In Santa Monica Bay, it has been observed in the fall and winter (August to January, with occasional individuals in April), reaching population peaks about October (Tur- NER, EBERT & GIVEN, 1969). It has also been recorded in April at Santa Catalina Island (TURNER & EBERT, 1962). All other records (Table 1) are based upon fall and winter collections (August, October, November or Janu- ary) with the exception of the Shell Beach specimen, found in May. Two records are from kelp or kelp holdfasts (Santa Barbara and San Diego Counties), both also associated with rock bottoms. WILLIAMS (1949) stated Chlamydoconcha was found beneath rocks, cling- Vol. 21; No. 3 ing to dead shells of old rock oysters, Chama sp., but did not indicate a specific locality. NortH (1976) de- scribed it as occurring “‘beneath flat rocks and ledges,” to depths of 27m, in southern California. Its principally inner sublittoral occurrence and its rarity in the intertidal zone may account for the relatively few records. In 1974, SoLEM (pp. 81 - 82) made the following state- ment: “Until recently it was believed that a genus of clams found off Western North America, Chlamydo- concha, was a permanently swimming member of the plankton, with completely internal shell. A study issued early in 1973 concluded that this genus was based on ex- ceptionally long-lived larvae. It is not yet known to which adult clam these larvae belong, but the absence of any reproductively mature examples of Chlamydoconcha strongly suggests that this conclusion is correct.” These remarks actually concern the North and South Atlantic galeommatacean clam Planktomya (see ALLEN & SCHEL- TEMA, 1972). Chlamydoconcha has never been recorded in the plankton or as a planktonic animal, and reproduc- tively mature specimens are known (BERNARD, 1897b). The type series of Chlamydoconcha orcutti, not located at the time of preparation of the catalogue of Dall’s taxa (Boss et al., 1968) has since been found in the National Museum of Natural History (Smithsonian Institution) wet (alcoholic) collections. This material (old alcoholic series no. 2015) consists of a bottle, with a neck-label reading “San Diego C. R. Orcutt,” in which are 4 vials. One vial contains one dissected specimen and one entire specimen (the latter here designated the lectotype, US NM 758567, 10.1 mm in length and 9.4 mm in width; the former, a paralectotype, here designated, USNM 758568). A second vial contains 5 entire specimens (paralecto- types, here designated, USNM 758568). Two small vials contain shell fragments from the dissected specimen. The arrangement of the material into one dissected specimen, shells, and whole specimens, clearly corresponds with Dall’s original remarks and description of the species. In addition, there are 7 slides (J125 - J131, USNM 107222- 107234) of one entire animal which has been serially sectioned. The catalogue entry (of October 16, 1894) indi- cates that this specimen was received from J. A. Ryder, and collected by C. Orcutt from False Bay (= Mission Bay). Mount (1973) has indicated the presence of a syntype (which can now be regarded as a paralectotype) of Chlamydoconcha in the C. R. Orcutt collection now at the University of California at Riverside. Specimens examined are at the University of Califor- nia, Berkeley, Museum of Paleontology (UCMP), Cali- fornia Academy of Sciences, San Francisco, Department of Invertebrate Zoology (CASIZ), Moss Landing Marine THE VELIGER Page 377 Laboratories, Moss Landing, California (MLML), San- ta Barbara Museum of Natural History (SBMNH), the Los Angeles County Museum of Natural History (LA CM), and the National Museum of Natural History [NMNH, numbers of the United States National Museum (USNM)]. ACKNOWLEDGMENTS James McLean and Gale Sphon (LACM), F. G. Hoch- berg (SBMNH), James Nybakken (MLML), Joseph Rosewater (NMNH), Frank Bernard, Dave Mulliner, and the late Allyn G. Smith, provided useful informa- tion or permitted me to examine collections under their care. Eugene Coan and Barry Roth kindly reviewed the manuscript and provided helpful suggestions. Literature Cited Assott, Rosert Tucker 1974. American seashells. 20d ed.; 663 pp; 4000+ figs.; plts. 1 - 24 (in color). Van Nostrand Reinhold Co., New York ALLEN, JoHN A. & Rupor S. SCHELTEMA 1972. The functional morphology and geographical distribution of Planktomya henseni, a supposed neotenous bivalve. Journ. Mar. Biol. Assoc. U. K. 52: 19-31 BERNARD, FEL 1897a. Note préliminaire sur Chlamydoconcha orcutti Dall, lamelli- branche a coquille interne. Bull. Mus. Hist. Natur. Paris (1) (2): 1897b. Anatomie de Chlamydoconcha orcutti Dall, lamellibranche 4 coquille interne. Ann. Sci. Natur. Zool. Paleo. (8) 4: 221-252; 2 pits. Berry, SAMUEL STILLMAN 1907. Molluscan fauna of Monterey Bay, California. The Nautilus ar(1): 17-22 (13. May 1907) 21 (3): 34-35 (6 July 1907) 21 (4): 39-47 (16 August 1907) 21 (5): 51-52 (18 September 1907) 1908. Miscellaneous notes on Californian mollusks. The Nautilus 22 (4-5): 37-41 (5 September 1908) Boss, KENNETH Jay, JosEPpH ROSEWATER & FLORENCE ANNE RUHOFF 1968. The zoological taxa of William Healey Dall. U.S. Nat. Mus. Bull 287: 427 pp. Burcu, JoHN Quincy 1944. {On Chlamydoconcha orcuttt] Min. Conch. Club So. Calif. 40: 24 (October 1944) CHapmMAN, Gorpon A. 1963. Mission Bay. A review of previous studies and the status of the sportfishery. Calif. Fish & Game 49 (1): 30-43 CHAvAN, ANDRE 1969. Superfamily Leptonacea, pp. N518-N5g37 tn: Raymond C. Moore, ed., Treatise on invertebrate paleontology, Part N, Mollusca 6: Bivalvia, vol. 2. Geol. Soc. Amer. and Univ. Kansas Press ii+N4g1 to N592 DALL, WILLIAM HEALEY 1884. A remarkable new type of mollusks. Science 4 (76): 50-51 (18 July 1884) 1889. Synopsis of the Recent and Tertiary Leptonacea of North Ameri- ca and the West Indies. Proc. U.S. Nat. Mus. 21 (1177): 873 to 897; plts. 87 - 88 (26 June 1899) 1916. Checklist of the Recent bivalve mollusks (Pelecypoda) of the northwest coast of America from the Polar Sea to San Diego, Califor- nia. Southwest Mus., Los Angeles, Calif, 44 pp. (28 July 1916) Page 378 THE VELIGER Vol. 21; No. 3 Dati, Witt1am HEALEY 19021. 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 unfigured species. U.S. Nat. Mus. Bull. 112: 1 - 217; 22 pits. (24 February 1921) FiscHer, PauL 1887a. Sur un nouveau type de mollusques. Journ. Conchyl. (3) 35: 201 - 206 (1 April 1887) 1887b. Manuel de conchyliologie et de paléontologie conchyliologique ou histoire naturelle des mollusques vivants et fossiles. Paris. Lib- rairie F, Savy, xxiv+1369 pp.; 23 plts.; 1138 text figs. Gottinc, Kraus JurcEn 1974. Malakozoologie: Grundriss der Weichtierkunde. Stuttgart, Gustav Fischer Verlg. 320 pp. JoHNson, Myrtle ELIZABETH 1945. [On Clamydoconcha orcutt1] 44: back page (February 1945) 1953- Chlamydoconcha orcutti Dall. Amer. Malacol. Union, Ann. Reprt. (Pacific Division) 1953: 20-21 (abstr.) (31 December 1953) Keen, A. Myra 1963. Marine molluscan genera of western North America: an illus- trated key. Stanford Univ. Press, 126 pp. (14 February 1963) 1969. Superfamily Chlamydoconchacea, p. N537 tn: Raymond C., Moore, Treatise on invertebrate paleontology, part N, Mollusca 6: Bivalvia, vol. 2. Geol. Soc. Amer. & Univ. Kansas Press, iit+N491 to Min. Conch. Club So. Calif. N592 Keen A. Myra & Eucene Victor Coan 1974. Marine molluscan genera of western North America. An illus- trated key. Stanford Univ. Press, x+208 pp. (2 May 1974) Keep, Josian 1904. West American shells. Francisco, 360 pp.; illust. Keep, Jos1an & JosHuA LoncsTReTH Balty, Jr. 1935. West coast shells. Stanford Univ. Press, xii+350 pp.; illust. Ke.sey, FW. 1907. Mollusks and brachiopods collected in San Diego, California. Trans. San Diego Soc. Nat. Hist. 1 (2): 31-55 Morrison, Roy The Whittaker & Ray Company, San 1952. Environmental change on molluscan life in Mission Bay, San Diego. Ann. Rprt. Amer. Malacol. Union (Pacific Div.) 1952: 32 (abstr.) 1954. A molluscan study of Mission Bay’s newly formed shore line at San Diego, California. Ann. Rprt. Amer. Malacol. Union (Pa- cific Div.) 1954: 5-6 (abstr.) 1957. Molluscan life and collecting in Mission Bay, before and after dredging. Ann. Rprt. Amer. Malacol. Union (Pacific Div.) 1957: 28 (abstr.) Mount, Jacx Doucrias 1973. Type specimens of Mollusca from the Charles R. Orcutt collec- tion now at the University of California, Riverside. The Veliger 16 (2): 200-202 (1 October 1973) NortH, WHEELER J. 1976. Underwater California. Univ. Calif. Press, Berkeley Oxproyp, Ipa SHEPARD 1925. The marine shells of the west coast of North America. Stan- ford Univ. Publs. Univ. Ser. Geol. Sci. 1 (1): 1-248; 57 pits. Orcutt, Cuartes RusseLy 1885. Notes on the mollusks of the vicinity of San Diego, Cal., and Todos Santos Bay, Lower California. Proc. U. S. Nat. Mus. 8 (35): 534-552; pit. 24 (30 September 1885) 1900. West American Mollusca. West Amer. Sci. 11 (5): 47-49 (June 1900) 19152. Molluscan world. West Amer. Sci. 19 (1):1-2 (July 715) 1915b. Molluscan world. Vol. I. San Diego, Calif. 1-208; 1-62 pp. 1919. Shells of La Jolla, California. The Nautilus 33 (2): 62-67 (6 November 1919) Calif, Nat. Hist. Guides 39: 276 pp. SuirH, Attyn Goopwin 1960. Amphineura, pp. I41 - 176 in: Raymond C. Moore, ed., Treatise on invertebrate paleontology, Part I, Mollusca 1, Geol. Soc. Amer. and Univ. Kansas Press, xxiiit+I1 - 1351 Sante, ALtyN Goopwin & MACKENZzIE GorpoN, Jr. 1948. The marine mollusks and brachiopods of Monterey Bay, Cali- fornia, and vicinity. Proc. Calif. Acad. Sci. (4) 26 (8): 147 - 245; pits. 3, 4; 4 text figs. (15 December 1948) Sotzm, ALAN 1974. The shell makers: introducing mollusks. John Wiley & Sons, New York, xii+288 pp. THIELE, JOHANNES 1934. Handbuch der systematischen Weichtierkunde. 2 (3): 779 to 1154; figs. 784 - 893 Turner, CHarves H. & Earu E. Esert 1962. The elusive naked clam. Shells and their neighbors 14: 4 (December 1962) Turner, Cnarves H., Eart E. Esert & Ropert R. Given 1969. Man-made reef ecology. Calif: Dept. Fish & Game, Fish Bull. 146: 221 pp ; 74 text figs. Voxes, Haron E. 1967. Genera of the Bivalvia. A systematic and bibliographic cata. logue. Bull. Amer. Paleo. 15: 103 - 394 WiLuiamMs, WoopBRIDGE 1949. The enigma of Mission Bay. Calif. Acad. Sci., Pac. Dis- covery 2(2): 22-23 (March-April 1949) Vol. 21; No. 3 THE VELIGER Page 379 Description of a Previously Misidentified Species of Epitonium (Gastropoda : Epitoniidae) BY HELEN DuSHANE 15012 El Soneto Drive, Whittier, California 90605 (2 Text figures) LONG CONSIDERED to be Epitonium (Nitidiscala) barbar- inum Dall, 1919, a species common intertidally along the northern shores of the Gulf of California, Mexico, is in need of a new name. The confusion was caused by Da.i’s (1921: 116) range from San Diego, California to Pana- ma. The holotype of E. barbarinum (USNM 46229), type locality San Diego, California, is a specimen of Epitonium (Epitonium) angulatum (Say, 1830), from the Atlantic seaboard and the Gulf of Mexico. A new name is chosen herein for the small species previously known as E. (N.) barbarinum Dall, 1919. Epitonium (Nitidiscala) arcanum DuShane, spec. nov. (Figure 1) Description: Shell small in size, white; nuclear whorls 3, Opaque, somewhat eroded even on live-taken material ; subsequent whorls 5 to 7; spiral sculpture sometimes faint on first 2 whorls below the nuclear whorls; suture im- pressed but not deep; costae 13 to 17, very slightly re- flected, thin-edged, heavier where they join the suture, sometimes slightly shouldered, dipping under the lip; a- perture oval; lip entire, slightly patulous and without spine; operculum thin, horny, paucispiral. Length, 5 to 12mm; width, 2 to 6mm. Type Material: Holotype, Los Angeles County Museum of Natural History, Type Collection no. 1264. Paratypes: Four each will be deposited in the following institutions: American Museum of Natural History; Cali- fornia Academy of Sciences; Los Angeles County Muse- um of Natural History; Santa Barbara Museum of Nat- ural History; United States National Museum. In addi- tion, paratypes are in the collections of the following: Twila Bratcher (2); Roy Poorman (2); Donald Shasky (4) ; Carol Skoglund (2) ; Helen DuShane (86). Type Locality: Puertecitos, Baja California Norte, Mexico (30°20’02”N; 114°38’08” W), collected inter- tidally from algae covered boulders; from under rocks edging the sand beach; dredged to 18m, shell and sand substrate. The range of this new species is restricted on the west side of the Gulf of California from San Felipe Figure 1 Epitonium (Nitidiscala) arcanum DuShane, spec. nov. Ventral view, holotype, LACM 1264; length 9mm; width 4mm Page 380 THE VELIGER Vol. 21; No. 3 Table 1 Character Epitonium arcanum Epitonium tinctum Epitonium angulatum Number of whorls 8-10 7-11 9-10 Sculpture of early whorls spiral in some specimens smooth smooth Number of costae 11-17 11-14+ 8-12 Shape of costae blade-like thick, coalescing into heavier blade-like, definite angle at costae near the lip whorl shoulder Size variation length 5-12 mm 4-15 mm 13-25 mm width 2-6 mm 1-6.5 mm 6.5-9 mm Suture impressed, noi deep deep deep Color band at suture none brown line in some none Aperture oval, patulous oval, patulous subcircular, lip held away from body whorl by costae, patulous south to 20km S of Puertecitos, Baja California Norte, Mexico, and on the east side of the Gulf of California from Cabo Tepoca south to Punta Penasco, Sonora, Mexi- co, above latitude 30°N. Discussion: Epitonium (Nitidiscala) arcanum differs from E. (N.) tinctum (Carpenter, 1865), with which it has been compared, by having a smaller shell, a different radula, and a different geographical range. Table 1 shows other differences. The radula of Epitonium arcanum indicates that den- tition is in the form of 20-40 broad rows of hook-like uncini with very little variation in shape along each row. The length of the teeth varies with the position of the teeth in the row, becoming progressively shorter with the distance from the center. The obtuse angles on the teeth are variable as to their precise placement. Radula and specimen of EF. arcanum, from Puertecitos, Baja Califor- nia Norte, Mexico, are at the San Diego Natural History Museum, San Diego, California (Figure 2). In E. tinc- tum, with which it has been compared, the tips of the teeth have a bifid structure unlike any other thus far re- ported. Figure 2 Epitonium (Nitidiscala) arcanum DuShane, spec. nov. Radula: the hook-like uncini vary with their position in the row The geographical range of Epitonium arcanum is in the Gulf of California, Mexico, above latitude 30° North. The range of E. tinctum is in the northeastern Pacific, from Bahia Magdalena, Baja California Sur, Mexico, north to Alaska. Etymology: ‘The specific name arcanum is derived from the Latin adjective arcanus, meaning “hidden,” or “se- cret,” referring to long hidden distinctiveness of this species. ACKNOWLEDGMENTS My thanks go to Dr. Myra Keen, Professor Emeritus, Stanford University for having read the manuscript and given helpful advice, and to Gale Sphon of the Los An- geles County Museum of Natural History for arranging the loan of type specimens. To Bertram Draper I am grateful for the photograph of the holotype of Epitonium (Nitidiscala) arcanum. 1 wish to acknowledge the extrac- tion of the radula by the late Dr. George Radwin and the drawing of it by Anthony D’Attilio. Literature Cited Dati, Witt1AM HEALEY 1919. Descriptions of new species of Mollusca from the North Pacific Ocean in the collection of the United States National Museum. Proc. U.S. Nat. Mus. 56 (2295): 293-371 (30 August 1919) 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 unfigured species. U.S. Nat. Mus. Bull. 112: 1 - 217; 22 plts. (24 February 1921) Say, THOMAS 1830 - 1834. American conchology, or descriptions of the shells of North America. Prts. 1 to 7; 258 pp.; 68 plts. New Harmony, Indiana Vol. 21; No. 3 THE VELIGER Page 381 Sexual Characteristics of Margaritifera margaritifera (Linnaeus) Populations in Central New England DOUGLAS G. SMITH Museum of Zoology, University of Massachusetts, Amherst, Massachusetts 01003 (1 Text figure) INTRODUCTION BIVALVE MOLLUSKS are considered to be characteristically dioecious (gonochoristic) (CoE, 1943). The few instances of consecutive or simultaneous hermaphroditism are be- lieved to be chiefly confined to species in which larval or developing young are brooded in the gills or demibranchs of the parent (FRETTER & GRAHAM, 1964). Furthermore, it is generally found that species which are hermaphro- ditic are typically found in harsh or fluctuating environ- ments. Both of the above conditions are characteristic of fresh water and tidal habitats. Hermaphroditism has been explored in the Holarctic fresh water Unionacea by a few investigators (BLOOMER, 1934; TEPE, 1943; HEARD, 1970, 1975; VAN DER SCHALIE, several papers, summarized in 1970). These studies showed that fully hermaphroditic species were rare, al- though many species contained an occasional hermaphro- dite. Populations of the Margaritiferidae, the most re- mote group morphologically within the Unionacea (Ort- MANN, 1911; HEARD & GUCKERT, 1970), have been ex- amined in Europe and North America. Studies by HENp- LEBERG (1960) and VAN DER SCHALIE (1966, 1970), complete with summaries of earlier investigations, have indicated that Margaritifera margaritifera sensu lato is normally dioecious with only an occasional hermaphro- dite being evident. HeEarp (1970) examined specimens of Margaritifera falcata (Gould, 1850) occurring in North American Pa- cific drainages. Finding all his material hermaphroditic, he concluded that M. “falcata” was hermaphroditic, thus proving an exception to the supposition of uniform uni- sexuality among the Margaritiferidae. However, VAN DER SCHALIE (1970) listed the locality of his own (1966) M. margaritifera material (cited by HEARD, 1970) as occur- ring in the Snake River watershed in Wyoming. The Snake River drains the Pacific side of the Continental Divide and the Margaritifera inhabiting these waters is M. m. falcata (= M. “falcata’) (Henderson, 1935). Each study was on a single population sampled on a spe- cific date. Assuming that van der Schalie’s material was “falcata,” it is uncertain whether M. “falcata,” as a whole, is distinctly hermaphroditic, or dioecious with occasional hermaphroditism, although BurcH (1973) used hermaphroditism as a criterion distinguishing M. “falcata” from M. margaritifera. The present study analyzes several populations of Mar- garitifera margaritifera inhabiting the Connecticut River system in central New England. Histological examination of the gonads was performed to determine sexual charac- teristics of these populations. Individuals of all ages col- | lected at different times of the year were sectioned. Special attention has been paid to the distribution of sexes with respect to age, and to the possibility of sex reversal (s). METHODS anp MATERIALS A total of 52 specimens was utilized for visceral histo- logical examination. All specimens were fixed in 10% formalin and preserved in 70% isopropyl alcohol. The collections represent 13 populations occurring within the Connecticut River watershed in Massachusetts. A randomly collected sample, (MO. 896) Munn Brook, Westfield, Hampden County, of 18 specimens was used for sex ratio determination. All preserved material rele- vant to this study is maintained in the invertebrate collec- tions of the Museum of Zoology, University of Massa- chusetts at Amherst. Page 382 THE VELIGER Vol. 21; No. 3 ee een Three specimens from a single locality (MO. 683 ) were selected for exploratory sectioning of gonads. All removed portions were embedded in paraffin and serially sectioned at 8pm. Sections were then dehydrated in alcohol, cleared in xylene, stained and mounted with Pycolite. The serial sections were stained principally with Harris’ hematoxylin and counterstained with eosin. Some material was stained with Ehrlich’s hematoxylin. Fast green and acid fuchsin were also occasionally used as counterstains. All parts of the gonad of each animal were removed and sectioned for examination for possible hermaphrodi- tism. At least 25 slides, each consisting of about 4 sections, were prepared for each individual. This method was spe- cifically employed in order to reveal rare tissues of an op- posite sex in the same gonad, assuming that all animals were normally hermaphroditic. This criterion is based on Hearp’s (1970) statement that, although Margaritifera “falcata” was normally hermaphroditic, male gonadal tissues were fewer than female. At least 10 slides per animal were prepared for the re- maining material except MO. 896 (18 specimens) and 7 follow-up specimens for which 5 slides per animal were prepared. Ages of mussels 10 years and younger were determined by counting shell annuli, while older specimens’ ages were determined by the application of growth curves de- veloped previously for age analysis of Connecticut River system populations (SmiTH, 1976). RESULTS anp DISCUSSION Histological analysis of the gonadal tissue of investigated mussels show that Margaritifera margaritifera in central New England is dioecious. Not a single case of herm- aphroditism was disclosed. Inspection of gonads removed from specimens collected at different time intervals during the growing season (spring-fall), and including the re- cruitment period, did not reveal any follicular units under- going sexual transformation, suggesting that individuals remain in a specific sex state during the warm season. It is not evident , however, whether an animal can undergo sex reversal at other times of the year nor if animals engage in sex changes at some particular period during their lifespan. All inspected adult animals participated in the late summer - fall recruitment. Normal gametogenesis was observed from mid-May to early August after which spawning commences (SmiTH, 1976). Sperm morulae, as described and discussed by vAN DER SCHALIE & LOCKE (1941) and Hearp (1969, 1975) for other freshwater mussel species, were present in male follicles during June. By July all sperm morulae had disappeared and the acini were fully charged with mature sperm. Mature ova in females began appearing by mid-June and all acini con- tained fully mature ova during July. The histological evi- dence available during the spawning period indicates that females deposit eggs into the demibranchs prior to the release of sperm by males, suggesting that fertilization occurs after the eggs are in the demibranch marsupia. Following deposition of eggs, a few mature and immature oocytes remain in the ovary, however; these are appar- ently resorbed after a few weeks. Identifiable sex cells are seen in animals between 7 and g years of age, whereas sexual maturity, as indicated by the ability to produce mature gametes, is not achieved for another year or so. The differences in time to reach sexual maturity appeared to be sex-dependent in examined mus- sels. Males apparently mature 1 to 2 years earlier than females (Figure 1). A female probably does not function reproductively until its 9" year, which is halfway through its normal lifespan of 19 to 25 years estimated by SmrrH (1976) for populations in central New England. Shell length (mm) 2 4 6 8 10 12 Age (years) Figure 1 Distribution of juvenile and young adult specimens + — sex cells are unrecognizable © - males @ - females Sexual maturity is gradual, as succeedingly older mus- sels show greater amounts of gonadal tissue per unit area Vol. 21; No. 3 THE VELIGER - of viscera. After mussels have become fully functional reproductives the correlation between the dominance of a particular sex and individual age disappears. Mature mus- sels of each sex are nearly equally distributed. Analysis of the Munn Brook population shows a moderate (5:3 or 23%) preponderance of females over males in the g to 15 year age category. This ratio slightly exceeds that given by PELSENFER (1926) for several unrelated molluscan forms he studied. However, the dominance of females over males is in agreement with his observations. The available in- formation does not indicate any protandric tendencies, although a slight male over female dominance existing in the pre-g year old classes is replaced by a female over male dominance later on. Males are present in the older age classes of the Munn Brook population and among other examined specimens from many populations, large older males (> 100mm shell length) are abundant. The reasons for early male dominance followed by fe- male dominance later on can not be explained by the available evidence and deserves further study. However, the appearance of males before females has been demon- strated for rhythmic and protandric hermaphroditic mol- lusks (Cok, 1936). Early male preponderance has been suggested to be the result of bioenergetic economics wherein it is functionally easier or more economical to be male than female (RussELL-HUNTER « McManon, 1976). ACKNOWLEDGMENTS I should like to thank Dr. Herbert Potswald for his advice and material assistance and Dr. Drew Noden for his material assistance. I should also like to thank Ms. Ann Pratt for her help in preparing many of the sections and for reading the manuscript. Page 383 Literature Cited Bioomer, H. H. 1934. On the sex, and sex-modification of the gill, of Anodonta cyg- nea. Proc. Malacol. Soc. London 21: 21 - 28 Burcu, JoHN Bayarp 1973. Freshwater Unionacean clams (Mollusca: Pelecypoda) of North America. U.S. Environm. Protect. Agency, Biota of Freshwater Ecosyst., Manual 11: 176 pp. Coz, Wes_zey RosweLi 1936. Sex ratios and sex changes in mollusks. Mém. Mus. Roy. Hist. Nat. Belg. (12) 3: 69 - 76 1943. Sexual differentiation in mollusks. I. Pelecypods. Quart. Rev. Biol. 18: 154 - 164 FreTTER, VERA & ALASTAIR GRAHAM 1964. Reproduction. pp. 127-164 in: K. M. Wilbur & C. M. Yonge, eds. Physiology of Mollusca, vol. 1. Academic Press, New York HeEarp, Wiiu1aMm H. 1969. Seasonal variation in gonad activity in freshwater mussels, and its systematic significance. Bull. Amer. Malacol. Union 1969: 53 1970. Hermaphroditism in Margarttifera falcata (Gould) (Pelecypoda: Margaritiferidae). The Nautilus 83: 113 - 114 1975. Sexuality and other aspects of reproduction in Anodonta (Pele- cypoda: Unionidae). Malacologia 15: 81 - 103 (8 Dec. 1975) Hearp, WiriiaM H. « R. H. GucKxert 1971. A re-evaluation of the Recent Unionacea (Pelecypoda) of North America. Malacologia 10: 333 - 355 (10 July 1971) HeNDELBERG, J. 1960. The fresh-water pearl mussel, Margaritifera margaritifera (L.). Rprt. Inst. Freshwat. Res. Drottningholm 14: 149-171 HENDERSON, JUNIUS 1935- Margaritifera and Fluminicola in Wyoming. The Nautilus 48 (3): 107 (26 January 1935) OrTMANN, ARNOLD EDWARD IQII. A monograph of the najades of Pennsylvania. Parts I & II. Mem. Carnegie Mus. 4: 279 - 347 PELSENEER, PAUL 1926. La proportion relative des sexes chez les animaux et particu- ligrement chez les mollusques. Mém. Acad. Roy. Belg. Sci. 8: 1-256 Russe_i-Hunter, W. D. & R. EF McMaHon 1976. Evidence for functional protandry in a fresh-water basommato- phoran limpet, Laevapex fuscus. Trans. Amer. Microsc. Soc. 95: 174 - 182 SmitH, Douotas G. 1976. Notes on the biology of Margaritifera margaritifera margaritifera (Lin.) in central Massachusetts. Amer. Midld. Natur. 96: 252 - 256 Terz, W. 1943. Hermaphroditism in Carunculina parva, a freshwater mussel. Amer. Midld. Natur. 29: 621 - 623 VAN DER SCHALIE, HENRY 1966. Hermaphroditism among North American freshwater mussels. Proc. 2nd Europ. Malacol. Congr. Vienna. Malacologia 5 (1): 77-78 (31 December 1966) 1970. Hermaphroditism among North American freshwater mussels. Malacologia 10: 93-112 (14 November 1970) VAN DER SCHALIE, Henry & F LocKe 1941. Hermaphroditism in Anodonta grandis, a fresh-water mussel. Univ. Mich. Mus. Zool. Occ. Pap. 432: 1-7 Page 384 THE VELIGER Vol. 21; No. 3 The Population Dynamics of Two Sympatric Species of Macoma (Mollusca : Bivalvia) BY JOHN GIBSON RAE, III' Pacific Marine Station, University of the Pacific, Dillon Beach, California 94929 (17 Text figures) INTRODUCTION THE ECOLOGY oF FEW intertidal deposit feeding bivalves has been studied. Variations in abundance have been studied for Macoma balthica for salinity (McERLEAN, 1964), tidal height (VassaLLo, 1969, 1971; GREEN, 1973) and substrate gradients (NEWELL, 1965) and for Tellina tenuis (STEPHEN, 1928) and Scrobicularia plana (HUucHES, 1970) for varying tidal heights. Macoma secta (Conrad, 1837) and M. nasuta (Con- rad, 1837) are geographically sympatric species of the bivalve family Tellinidae. Macoma secta occurs in inter- tidal sand flats from Vancouver Island, British Columbia, to Bahia Magdalena, Baja California, while M. nasuta occurs in muddier substrates intertidally from Kodiak Island, Alaska, to Cabo San Lucas, Baja California (Coan, 1971). RickeTTs, Cavin & HEDGPETH (1969) list M. secta as occurring in the Middle Intertidal Zone and M. nasuta in the Low Tide Horizon. They are found in decreasing numbers to 25 fathoms [45m] (Assort, 1954). Macoma secta and M. nasuta are the characteris- tic species of the Macoma community on the west coast of North America. THorson (1966) identified 5 Maco- ma communities worldwide. Descriptive distribution ecology has been studied for Macoma secta, M. nasuta and 2 other Macoma species in relation to substrate (ADDICOTT, 1952). The present study is concerned with the population ecology of M. secta and M. nasuta as insight to comparative life history strategies. Population dynamics studied include population struc- ' Present address: Department of Zoology and Microbiology, Ohio University, Athens, Ohio 45701 ture, spatial and temporal abundance patterns, popula- tion variability with tidal height, fecundity, recruitment and evidence of density dependence. MATERIALS anp METHODS Macoma secta and M. nasuta occur in sympatric popula- tions on a sand flat known locally as Lawson’s flat. This area is located 1.28 km from the entrance to Tomales Bay, just south of Dillon Beach, California. On the basis of an extensive stratified random survey of clam abundances with tidal height in June, 1974, at Lawson’s landing, an area was staked out for future study. The area started at the 0.0 tide level and continued shoreward to the upper- most limit of distribution of Macoma. This upper limit is coincidentally obvious to the eye because the soil topo- graphy changes. This is due to biogenic working of the substrate above the area. There is also a 5cm “cliff” at this transition zone. On surveying this “cliff” at various points on the beach, it was determined as 72+3cm from mean lower low water (MLLW). This corresponds to MLHW, one of Doty « ARCHER’s (1950) critical tide heights. The resulting area was 35 m long (perpendicular to shore) by 10m wide. This was subdivided into 5 areas, each 7m long by 1om wide, for purposes of stratified random sampling along the tidal gradient. In order to examine changes in abundance and size distributions with time and intertidal position, the clams were sampled every 2 months from August, 1974, to Au- gust, 1975. Three random samples were dug in each area. A 50cm X50cm frame was used and the holes were dug to a depth of ca. 70cm in order to include all clams. The resulting pile of sand was searched twice by crumbling Vol, 21; No. 3 the soil in the hand. All clams were identified, counted and measured for length to the nearest millimeter. They were then returned to thc hole which was refilled. It is felt that this method is accurate for clams of 1cm and larger. Distributional data on clams less than 1cm long were obtained by monthly sampling of the 5 areas with the exception of biweckly sampling for a period of time after first recruitment. Ten cores (diameter 7.3cm X I1.0cm long) were taken at random from each area and later sieved with a 1mm sieve. The time and intensity of re- cruitment was also determined by this sampling proce- dure. Estimates of fecundity in Macoma are difficult to ob- tain by usual methods. The bivalves will not readily spawn in the laboratory and since the gonads are impossible to excise accurately, they cannot be weighed. In order to obtain estimates of fecundity, samples were collected for each species in February and August, 1975. On the basis of histological study of the gonads (Rar, 1975) these times represented, respectively, the inactive and ripe pha- ses of gonad sexuality. The hypothesis to be tested was whether or not the clams changed weight from winter to summer beyond that attributed to growth alone. Basic to this study was the assumption that any increase in weight disproportional to length was due to the added biomass of gametes. In order to obtain this estimate, each clam was numbered and measured for length with vernier cali- pers to o.1 mm. Each individual’s dry weight was obtained using only the soft tissue which was desiccated in an 80°C oven until constant weight was achieved. THoRSON (1957) indicated dry weight yields better biological data than wet weight. Lines were fitted to the resulting length-weight data points and compared. Size frequency data for the months August, 1974, Feb- ruary and August, 1975 were used to estimate the stand- ing biomass in dry weight for each species at times when the populations were inactive and ripe with respect to gametogenesis. Shell lengths were converted to grams dry weight by the length-weight relationships outlined above for the respective months. The weight was multi- plied by the clam abundance in each size class and all weights were summed. The resulting value was adjusted to a final value of dry weight in grams per m’. The phoronid, Phoronopsis harmeri, was also sampled bimonthly because it has been demonstrated to affect Macoma densities (T: Ronan, personal communication). Five random samples were taken in each area with a IocmXt1ocm frame. In lieu of digging, the “burrows” were counted for an estimate of abundance. Counts were taken during calm weather so that wave action would have minimal effect on the “burrows.” THE VELIGER Page 385 The tidal height of each area was determined by sur- veying. On an expected tide of -24 cm with a barometric reading close to 750mm and no wind blowing, a stake was driven into the mud at the point of furthest tidal re- treat. This height was then double checked against a later -24 cm tide and points were subsequently surveyed. Cursory sand analysis was performed in July, 1975 when one small core (3.3cm diameter by 6.3cm long) was taken from each area. The core was weighed wet and then weighed dry after desiccation in a 110°C oven. The samples were then gently broken up by mortar and pestle and dry sieved in a dry sieve series for 15 minutes. Result- ant fractions were weighed on a Torbol balance. RESULTS Study Area The slope of the beach was slight, averaging only 2.0%. There was, however, a distinct change in slope between areas 2 and 3. The sediment appeared sandy above this point and muddy below. The mean particle size was fair- ly constant across the area at approximately 245 um. The percent mud (>4®) by weight was less than 1% with the exception of area one which was 5.4%, resulting in es February 1975 20 € 16 cud & PS Tt (>) a g ae 8 4o o 30 -2 9 4 2D 6 10 & fe) o 9 Zz I zi 3 4 5 low high Area Figure 1 Mean abundances for each area for February, 1975 (1) Macoma secta ( ) (2) Macoma nasuta (— - — -) number of clams per 0.25 m? (3) Phoronopsis harmeri ( .... ) number of phoronids/o.o1 m? Vertical bars represent 95% confidence intervals Page 386 the lower mean particle size of 224 um. The water con- tent by weight was approximately 19.87% throughout the area. Intertidal Distribution of Species An example of the intertidal distribution of the species of interest is given in Figure 1. For Macoma, the mean abundance for each species is the average of the 3 samples taken in the respective area. For Phoronopsis, abundance is averaged from the 5 samples taken in each area. The month of February was a typical month. As will be shown later, the species were temporally stable in abundance. Macoma nasuta is found low in the intertidal zone. The species was most abundant in area 1 where the substrate was muddy. Decreasing abundance in area 2 may be correlated with the less muddy substrate or it may mark the upper limit of the population’s distribution. Through- out the sampling program, only 3 M. nasuta were found higher, one in area 3, one in area 5 and one above the sampling area. The distribution of Macoma secta covered all 5 areas. In area 1, the counts were sparse but consistent; this probably marked the lower fringe. The greatest densities were found in areas 2 and 3. Abundance dropped in areas 4 and 5. The soil change, already described, marked the upper limit of M. secta’s distribution. Up to this boundary high densities were found and just above, no M. secta were ever found. This suggests adverse biotic relations with another species. Just above the boundary the ghost shrimp, Callianassa californiensis, was abundant. Both animals are deposit feeders, suggesting possible compe- titive exclusion. SEGERSTRaLE (1965) reported a case where Macoma balthica and the amphipod Pontoporeia affinis had a strong inverse abundance relationship. He suggested predation of the Macoma larvae by the amphi- pod. The distribution of Phoronopsis harmerz is important to the study of Macoma for several reasons. Dense beds of the phoronid have been known to smother M. secta entirely (T: Ronan, personal communication). Lesser den- sities may seriously hinder Macoma’s movements. As Fig- ure I indicates, the phoronid’s distribution closely approx- imated M. secta in range and area of peak abundances. Shell length data for Macoma collected in February, 1975 are presented in Figure 2. Because the mean shell length of the M7. nasuta population is rather variable with time, February data are not typical. It will be shown that this month is highly typical of M. secta, however. The largest individuals were found in areas 1 and 5, while areas 2 and 3 had consistently smaller clams. Two THE VELIGER Vol. 21; No. 3 February 1975 Shell length (cm) high Figure 2 Mean shell length for each area for February, 1975 (1) All Macoma secta ( ) (2) Adult M. secta(....) (3) All Macoma nasuta (-— -— - -) Vertical bars represent 95% confidence intervals curves are shown for M. secta; the higher one does not include the young of the year, which were never abun- dant, but their small size statistically masked the inter- tidal size distribution of the adults. Spatial and Temporal Changes in Population Ecology Macoma secta The change in mean density with time is presented in Figure 3. The grand mean cuts through all 95% con- fidence intervals. The extreme stability of mean abun- dance is indicated by the fact that the grand mean passes between 6 of the 7 50% confidence intervals. Analysis of Vol. 21; No. 3 THE VELIGER Page 387 20 variance indicated no significant changes in mean density (F, (6, 98 df) = 0.288, p > 0.75). The population was rather stable in size composition. It 15 was a bimodal distribution until June, 1975 when it be- No. clams/{m? } fo) A SO IN WwW I MN Il yp ya 1974 1975 Month Figure 3 Overall mean abundance per 0.25 m? for Macoma secta Thin vertical bars represent 959 confidence intervals; thick verti- cal bars represent 50% confidence intervals. Grand mean is also shown a 3 E 50 a Dec. 1974 Aug. 1975 0 fo) fo) 2 6 2 Feb. 1975 4 © Co) fo) 2 4 6 8 Shell length (cm) Figure 4 The size frequency distribution for Macoma secta remained rather stable. June, 1975 illustrates the o+, 1+ and adult groups came a trimodal distribution (Figure 4). The adults formed the largest mode and the 1 or 2 smaller modes rep- resent the youngest age groups (o+ and 1 +, respectively). To test for changes in size frequency distributions, the non-parametric Kolmogorov-Smirnoff test was used. The size distribution for each sampling time was tested against all other times. Results are presented in Table 1 (SrEcEt, 1956, table M for large samples). Out of 21 comparisons, only 2 (10%) were significant at the 0.05 level. This is due to the 0+ group attaining a size of 1cm in August, 1975: Changes in mean length are summarized in Figure 5. The mean length ranged from 5.0 to 5.5 cm and analysis of variance showed these changes to be significant (F, (6, 1290 df) = 2.60 p < 0.025). ANOVA was repeated ex- cluding the August, 1975 data and changes in size were not significant (F, (5,1086 df) 1.059 0.5 > p > 0.25). This conclusively indicates the influence of the 0+ group on population length in August, 1975, the recruiting pe- riod. Analysis of variance for the spatial-temporal analysis of abundances is given in Table 2. As shown, changes in 5.0 Shell length (cm) K 3° @ Wf ID yo ie wt ANE a} 1974 1975 Month Figure 5 Mean shell length for Macoma secta. Symbols as in Figure 3 Page 388 THE VELIGER Vol. 21; No. 3 Table 1 Macoma secta—Kolmogorov-Smirnov test results 1974 1975 1975 Aug. Oct. Dec. Feb. Apr. Jun. Aug. 1974 Aug. — Oct. ns — Dec. ns ns — 1975 Feb. ns ns ns — Apr. ns ns ns ns = Jun. ns ns ns ns ns = 1975 Aug. * ns “ ns ns ns = Macoma nasuta— Kolmogorov-Smirnoy test results 1974 1975 1975 Aug. Oct. Dec. Feb. Apr. Jun. Aug. 1974 Aug. — Oct. ns — Dec. ns ns _ 1975 Feb. ns ns ns — Apr. * * * ns — Jun. ns ns iM ns ns — 1975 Aug. * * * = ‘ ns _ *_ Significance at 5% level. ns— Non significance. Table 2 Model II 2 way Analysis of Variance for the spatial-temporal analysis of abundances for Macoma secta. Source df SS MS Fs Probability Subgroups 34 3893.96 114.53 A (areas) 4 3562.53 890.63 84.10 p< 0.001 *** B (times) 6 77.16 12.86 1.21 0.50 > p > 0.25 ns AXB 24 254.27 10.59 1.31 0.25 >p>0.10 ns Within Subgroups 70 564.00 8.06 Total 104 4457.96 Table 3 Model II 2 way Analysis of Variance for the spatial-temporal analysis of abundances for Macoma nasuta. Source df SS MS Fs Probability Subgroups 13 298.310 22.95 A (areas) 1 197.167 197.17 31.4 p < 0.005 B (times) 6 63.476 10.58 1.68 0.50 > p > 0.25 AXB 6 37.667 6.28 1.35 0.50 > p > 0.25 Within Subgroups 28 130.667 4.67 Total 4] 428.976 Vol. 21; No. 3 TE VEEIGER Page 389 abundance were highly significant (p < 0.001) for tide levels, but changes were nonsignificant with time. In addition, there was no tidal level X time interaction. Macoma nasuta Changes in the mean density of Macoma nasuta per 4m’ are shown in Figure 6. Stability in abundance is demonstrated since the grand mean intersects all 95% 10 8 E = 6 € a ‘S) oe o PX SS Oy IN| ID) If 2B IM NIE If aS 1974 1975 Month Figure 6 Overall mean abundance per 0.25 m? for Macoma nasuta. Symbols as in Figure 3 confidence intervals. Density appears more variable than in M. secta however, since the grand mean passes through only 4 of the 7 50% confidence intervals. Analysis of vari- ance showed that differences between means were not significant (F,(6,42 df) = 0.781 0.75 > p > 0.5). This clam has a rather variable size frequency distribu- tion with time in comparison with Macoma secta. In June and August there was great influx of the o+ group indicating recruitment. The Kolmogorov-Smirnoff test (with adjustments for small samples: MILLer « Kann, 1962. appendix G) was used as before (Table 1). Of 21 comparisons, g were significant (43%). This is in part due to recruitment. Note the apparent lack of success of recruitment in August, 1974 (Figure 7). The mean size of Macoma nasuta varied greatly in time (Figure 8) ; in this case from 3.1 - 4.4cm. Tempo- ral differences in means were highly significant (ANOVA F, (6,176 df) = 8.49 p < 0.001). 20 Aug. 1974 10 10) Oct. 1974 Jun. 1975 10 > iS) 5 3 0 oa £ Fate. Dect 1974 10 fo) = Feb. 1975 10 ° fo) 2 4 6 Shell length (cm) Figure 7 The size frequency distribution for Macoma nasuta for June, 1975 The recruits (0+), 1+ and adult groups are easily detected Two way ANOVA was performed on the distribution data and is given in Table 3. The abundances differed with tidal height (p < 0.005), but there were no differ- ences in abundance with time and there was no signifi- cant interaction. Population Variability with Tidal Height It has been proposed that environmental variability and population variability are strongly correlated, as suggest- ed by GREEN (1969) who postulated that population a- bundances would show more variability in the higher intertidal areas where greater environmental unpredict- ability is thought to exist. Green’s measure of popula- Macoma nasuta Page 390 THE VELIGER Vol. 21; No. 3 2¢ @ AMfacoma secta 5.0 & Z | bo 5 4.0 3 2p : i n s 5 P=) o io & 20 s 3 3 o a AS © MN Dj F wA My yf A 1974 I Month cB Figure 8 Mean shell length for Macoma nasuta. Symbols as in Figure 3 tion variability was the Population-Time Mean Square which is that portion of the variance from analysis of variance which is attributable to differences from time to time (the Among Means MS). This is plotted on a logarithmic scale against tidal height. The Population-Time MS’s for Macoma secta and M. nasuta are plotted in Figure g. Regression of Population- Time MS against tidal height for M. secta was not signifi- cant (t(3 df) =0.255 0.9 >p>o0.5). This suggests that the environmental variability was the same for the clam at each tidal height. Since M. secta burrows deeply into the substrate, they may occur in upper areas but not be appreciably affected by surface environmental con- ditions. The clams burrow as deeply as their siphons are long (S. Obrebski, personal communication; AppicorrT, 1952) and consequently the larger clams may burrow deeper. As Figure 2 showed, the larger clams were found higher up in the intertidal zone and consequently deeper in the substrate. The effect, then, is to escape the environ- mental variability of the soil surface by adding a thermal and saline buffer of soil between the clams and the surface. That larger clams are found higher in the intertidal zone may be a range extension mechanism. Area No. Figure 9 Population Time Mean Square with tidal height for Macoma secta and M. nasuta. Relation shown: y = 0.49x + 9.6. Ordinate on logarithmic scale As only 2 data points are available for Macoma nasuta, comprehensive analysis is not possible; however, the value of the Population-Time MS for area 1 is high as com- pared with the M. secta data and especially high when compared to the intertidal animals GREEN (1969) dis- cusses. GREEN (1968) found a similar high stress situa- tion for the Mactrid bivalve, Notospisula, at lower levels, which was due to skate predation. Fecundity GaLTSOFF (1961) indicated that Macoma (probably M. balthica), has a low fecundity. Our estimates of fecun- Vol. 21; No. 3 dity in M. secta and M. nasuta started by examining their length to dry weight relationships in the inactive and ripe stages of gametogenesis and comparing them. These re- lationships are presented in Figures 10 and 11. Dry weight (gm) fe) I 2 3 4 5 6 7 8 Shell length (cm) Figure 10 Dry weight (g) against shell length (cm) for Macoma secta for February 20 (inactive) and August 10 (ripe). Ordinate on loga- rithmic scale. Febrary 20 (@) log n y=0.844x-4.951; r=0.93; t(24df) = 12.78***; F (1, 24 df) = 163.37***; August 10 (+) logn y = 0.927x—5.039; r = 0.97; t(28 df) = 21.75***; F, (1, 28 df) = 472.96*** (*** p < 0.001) All length-weight relationships for Macoma seeta were highly significant (p< 0.001). The seasonal curves in Figure 10 were analysed by analysis of covariance. ANCO VA showed that the 2 lines are significantly different in intercepts (F, (1, 53 df) =5.914 0.025 > p> 0.01) THE VELIGER Page 391 but not in the slopes (F, (1, 52 df) = 1.193 0.5 >p> 0.25). The general indication from these curves is that M. secta did add weight in summer and, as assumed, mostly gametes. The added weight seemed to be 25 - 50% of winter weight. This is considerable, but probably small if compared to other bivalve species. For Macoma nasuta, all length-weight relationships were also highly significant (p< 0.001). Analysis of Dry weight (gm) Oe els eS. oh A to Sus eh Ouniet iis S Shell length (cm) Figure 11 Dry weight (g) against shell length (cm) for Macoma nasuta February 20 (inactive) and August 10 (ripe). Ordinate on loga- rithmic scale. February 20 (@) log n y=1.015x-5.595; r=0.98; t(15 df) = 18.14***; F (1, 15df) = 329.14***; August 10 (+) logn y = 1.008x—4.670; f = 0.98; t(24 df) = 23.73***; F_ (1, 24 df) = 516.65*** (*** p < 0.001) covariance on the seasonal curves in Figure 11 indicated that the lines differed significantly in intercepts (F, (1, 40 df) = 178.299 p < 0.001), but not in slopes (F, (1, 39 df) 0.0073 p > 0.75). Consistent with general obser- vations, M. nasuta gained a great deal in weight in gam- etes in the summer. The clams more than doubled their weight, adding about 125% of winter weight as gametes. This was much greater than M. secta’s seasonal weight increase. Page 392 THE VELIGER Vol. 21; No. 3 Recruitment Having made some estimates of reproductive effort, it is of interest to examine the timing and intensity of recruit- ment. Recruitment for both species was sparse during the time of study. The first recruits were discovered on Janu- ary 22, 1975 for both species. On that date only 1 Maco- ma nasuta and 3 M. secta were collected. Their size ranged from 3.6 to 7.6mm. Through May, the few re- cruits found were in this general size range. It is unknown why smaller individuals were not found. By examining the reproductive data givenin Rak (1975) and adding a probable 6-weeks larval stage, I would ex- pect settlement of young to occur in October for Macoma secta and September, and from late October through late December for M. nasuta. The discrepancy between ob- served and expected times of settlement are not explain- able at this time. For both species, the average number of recruits was I per 10 cores (each area), which equals 24 per m? in the areas of recruitment. The Macoma nasuta recruits were found only in areas 1 and 2, the same as adults. The M. secta recruits were only found in areas 2, 4 and 5. These areas can quite con- fidently be called “nursery” areas. It is understandable that recruits of M. secta were not found in area 1 as it is a fringe area and muddy, but it is unknown why area 3 received no recruits. Macoma secta does move around a great deal in the substrate (S. Obrebski, personal com- munication), but evidently parallel to the shore. With only a very few exceptions, no young clams were ever found in area 3 when sampling for adults. This indicated that for 2 consecutive years, the “nursery”areas remained the same. There was some evidence that juvenile mortality is high among settled Macoma secta. During January and early February, most recruits were found in areas 4 and 5. However, from February 20 on, few were found in area 4 and none in area 5, It is possible that the 32.5 cm of rain in the first 13 days of February so stressed the young that high mortalities resulted in the upper areas. For juveniles, this area is unpredictable, but for adults it is highly pre- dictable. Juvenile Growth Macoma lives too deeply in the substrate and is difficult to sample, precluding mark - recapture studies of growth and survival. Previous attempts were unsuccessful (S. Obrebski, personal communication). The cohort of o+ recruits could be detected in quantitative samples ob- tained in January, 1975. The growth of this cohort and the older 1+ group consequently could be followed in time since they were clearly distinguishable in size from Shell length (cm) J JASON Dyk eM Arias 1974 197 Month 2 Figure 12 Juvenile growth of Macoma secta (0+ and 1+ groups shown) 95% confidence intervals shown the rest of the population. Growth data for these cohorts are summarized in Figure 12. As the graph indicates, growth for these cohorts occurred throughout the winter, although it was slower at that time. For this reason, annu- al rings were not found on Afacoma and data on age were unavailable. Standing Biomass and Gamete Production Macoma nasuta’s biomass (dry weight g/m?) was 10.6 for August, 1974, 4.3 for February, 1975 and 10.3 for August, 1975. This seems to indicate for the survey year that the biomass remained rather constant from summer to summer. It also indicated the great amount of energy the population expended in gamete production (10.3-4.3 we 5 - - 6.0 g/m? rhe ——10:0 : ——_— a = g/m*). This is AG ae X 100% 140% of winter weight expended in gamete production. The biomass for Macoma secta (dry weight g/m’) was considerably greater, 89.9 for August, 1974, 54.2 for Feb- ruary 1975 and 77.6 for August, 1975. The biomass of M. secta was considerably larger than that of M. nasuta and was relatively stable from August to August. Macoma secta expended 77.6 — 54.2 = 23.4 g/m’ in gamete pro- duction, 4 times that of M. nasuta, but only 23:4 8/m* 54.2 g/m X 100% = 43% of winter weight. For comparison, McIntyre (1970) obtained the range of biomass found for the Tellina tenuis community of Vol. 21; No. 3 which that species is a major part. The range was 0.3 -— 22.0 g/m? dry weight. Also, WARWICK & PRICE (1975) found the following values of biomass in dry weight averaged over the year: Mya arenaria 5.5 g/m?; Scrobi- cularia plana 2.1 g/m’; Macoma balthica 0.3 g/m’ and Cerastoderma edule 0.8 g/m’. Density Dependence in Macoma secta After examining the data on density and shell length of Macoma secta with tidal height (e. g., Figures 1 and 2) it became apparent that an inverse relationship existed between density and length for this population. The fol- lowing analysis provides a strong argument for density- dependent growth in this clam. Regression of mean shell length with mean density for each area sampled at different times was a significant (p < 0.001) inverse relationship as shown in Figure 13. The line plotted is only based on areas 2 through 5. This is done because area 1 was a fringe area, contained few 8 Mean shell length (cm) /Area fo) 5 10 15 20 25 Mean clam density/Area Figure 13 Mean shell length/area against mean abundance/area for Macoma secta Equation for areas 2 to 5: y =—0.1234x + 7.256; r = —0.72; t(26 df) = 5.349***; F (1, 26 df) = 28.614*** (*** p < 0.001) - August19 © December23 (April 20 + August ro @ October 12 X February 22 © June 14 THE VELIGER Page 393 individuals and was not representative of the population. The following hypothesis was advanced. As density in- creases, the resources per individual decrease; therefore the growth rate of the individual decreases. The hypothesis of density-dependent growth of indi- viduals was tested on the easily distinguished 1+ group which was living in the nursery areas 2 and 5. Analysis of variance indicated that area 2 was significantly more dense than area 5 over the time interval (p < 0.001). The growth of this cohort in the 2 areas is shown in Figure 14. Shell length (cm) iy AS ON Dy OP Wwe wey yA 1974 1975 Month Figure 14 Mean shell length of Macoma secta juveniles from dense (area 2, dashed vertical) and sparse (area 5, solid vertical) populations. Vertical bars represent 95% confidence intervals For each month following August, 1974, the means were significantly different. After 13 years of growth, the group in area 2 averaged 28 mm and the group in area 5 aver- aged 40mm. Further evidence of the extent of density- dependent growth is seen in Figure 15 for August, 1975, a typical month. In areas 2 and 3 all modes are further to the left than in the less densely populated areas 1, 4 and 5. Even the largest mode, which was composed of several year groups, was distinctly affected. It is of interest to know, for this population, what was the threshold density above which growth was negatively affected. To find this out, the cumulative length of clams found in each +m? sample was plotted against its biomass in numbers. Cumulative length was found to be the best measure of biomass because weight changed seasonally to the degree where relationships would be masked. This is shown in Figure 16. The 2 lines shown are (1) the calculated relationship, which assumes density-independent growth (dashed line), Page 394 THE VELIGER Vol. 21; No. 3 ee sen eee ee ee cree ee ae ————EEEEEEEE——————————————————_—_—_——_———=S August 1975 (0) 20 Area Il 10 to) 20 Area III 10 (0) 20 Area IV 10 (0) Frequency 20 Area 10 ) ) 2 4 6 8 Shell length (cm) Figure 15 Size frequency distributions of Macoma secta for each area in August, 1975 in which the slope is the grand mean shell length of all clams collected and (2) the actual relationship of biomass (cumulative length) per 0.25 m? sample against the num- ber of individuals in that sample (“density”), which shows density-dependence (solid line — regression of all points). Implicit in the calculated line showing density- Cumulative shell length (cm) /sample fo) 4 8 12 16 20 24 No. clams/4m? sample Figure 16 Biomass (cumulative shell length) with the number (abundance) of Macoma secta from each 0.25 m? sample. Equations: density dependent relation ( ). Calculated densi- ty independent relation (- — —). The slopes of the 2 lines were significantly different, t (92 df) = 4.245*** p < 0.001; calculated density independent relation y = 5.319x; density dependent rela- tion: y = 4.573x + 10.812; r=0.94; t (92 df) = 26.02***; F, (1, 92 df) = 676.78***. For each month sampled all relation- ships were highly significant; p < 0.001; 0.87 < r < 0.97. Symbols as in Figure 13 independence is the assumption that the mean shell length for the whole population for all sampling dates is the same for a density-independent or a density-dependent popu- lation. The density-dependent relationship is highly sig- nificant (p < 0.001) and the slopes of these 2 lines were shown to be significantly different (p< 0.001). These lines intersect at a density of 14.49 clams/o.25 m’. At that point density-dependence has no effect. At lower densities there is a relative abundance of food or space, or both, and at higher densities a crowded situation is found. As density increases, it is clear that the stress of reduced food and growth will result in a threshold density of emigration or mortality. Empirical data suggest this threshold was near 24 clams/o.25m’, as this was the highest density recorded. Vol. 21; No. 3 Phoronopsis harmert In order to obtain an estimate of phoronid population dy- namics a Two-way analysis of variance was run on the phoronid abundance data. The test indicated temporal stability of numbers (F, (6, 24 df) = 2.22 0.1 > p > 0.05) but differences in abundance with tidal height (F, (4, 24 df) —41.11 p) Figure 1 A. Dormant individual with perforate hibernation epiphragm. Stippled area is attached to the substrate in situ. B. View through first whorl behind aperture, showing layer of epiphragmal bubbles. Scale lines = 1 mm Vol. 21; No. 3 THE VELIGER Page 401 portant during the long periods of unfavorable conditions experienced by temperate species during winter. Super- cooling may be an important mechanism of freeze-resist- ance in hibernating land snails (Riddle, personal commu- nication) and contact of ice crystals or debris with the supercooled tissue might induce nucleation and freezing. The thickened winter epiphragm of Pupordes albilabris, together with the habit of attachment during dormancy, provides excellent mechanical protection for the animal during hibernation. The outer barrier is not complete, however, presumably because respiration requires the presence of a pore. The imperforate secondary layer of bubbles completes the closure of the aperture, and, pro- tected by the outer epiphragm, can be thin enough to allow diffusion of respiratory gases. It is interesting to note that other pupillid species examined (Gastrocopta armifera, G. contracta, G. pro- cera) did not form a thick hibernation epiphragm. In these species the aperture is protected by large lamellae which are lacking in Pupoides. A layer of thin epiphrag- mal bubbles, like that in Pupoides, was found at and behind the lamellae. Literature Cited BinnzEy, WiLL1AM GREENE & T. BLAND 1869. Land and fresh-water shells of North America. Smithson. Misc. Coll. 194 (1): xii+316 pp. Hora, S. L. 1928. Hibernation and aestivation in gastropod molluscs: on the habits of a slug from Dalhousie (Western Himalayas), with remarks on certain other species of gastropod molluscs. Rec. Ind. Mus. 30: 357 to 373 Macuin, J. 1968. The permeability of the epiphragm of terrestrial snails to water ~ vapor. Biol. Bull. 134: 87-95 Nopp, H. 1974. Physiologische Aspekte des Trockenschlafes der Landschnecken. Sitzungsber. Osterr. Akad. Wiss., math.-naturwiss. KI]. (1) 182: 1-75 PicHeEr, O. 1972. Atmung und Herzschlag einiger Landpulmonaten in Abhangig- keit von der Sauerstoffversorgung. Sitzungsber. Osterr. Akad. Wiss., math.-naturwiss. Kl. (1) 180: 195 - 215 Regs, W. J. 1964. A review of breathing devices in land operculate snails. Proc. Malacol. Soc. London 36: 55 - 67 Roxitxa, M. A. & C. FE Herren, II 1975. Formation of epiphragms by the land snail Otala lactea (Mil- ler) under various environmental conditions. The Nautilus 89 (1): 27-32 Page 402 NOTES & NEWS A Range Extension of Anachis lillianae Whitney, 1978 BY R. A. WHITNEY 2140 North Main Street, Decatur, Illinois 62526 Anachis lillianae Whitney, 1978, had been named from material collected at Playa Alicia near San Felipe, Baja California Norte, Mexico, under rocks at low tide, March, 1976. Other material examined had come from Bahia Adair, Sonora, Mexico; Libertad, Sonora, Mexico; To- polobampo Bay, Sinaloa, Mexico; Mazatlan, Sinaloa, Mexico; and San Blas, Nayarit, Mexico. All were col- lected intertidally. In addition, there was one isolated specimen that had been dredged from g.0 - 22.5m, off Punta Quepos, Puntarenas Province, Costa Rica, 9°52’ 43” N; 84°09'41” W. As the above list indicates, there is a band of collecting stations extending from Bahia Adair just north of Puerto Pefiasco to San Blas. The one potential station from which no specimens had been reported was Guaymas, Sonora, Mexico. As this area is rich in mollusks, it seemed prob- able that Anachis lillianae was present in this area, but unreported. On January 8, 1978, my wife and I were collecting shells at Soldado Bay, an area just N of Guaymas. We overturned rocks and swept the adhering material into vials for later examination and identification. At home we noted numerous specimens of Anachis pygmaea (Sow- erby, 1832), 2 A. hilli Pilsbry & Lowe, 1932, and one lone specimen of A. lillianae. We now can include Guaymas in the list of collecting stations and consequently assume that A. lillianae may be found intertidally along the west coast of Mexico from Bahia Adair, Sonora to San Blas, Nayarit. Errata The following corrections should be made in the article by Clifford M. Nelson in our October 1978 issue: Figures 6 and 7 should be transposed (on the first plate). THE VELIGER Vol. 21; No. 3 On page 210, right column, line 13, delete: southern. On page 214, under entry for Allison, 1977b, 3” line, substitute P for p in the word “programs.” On page 215, entry for Salin, 1972, 4™ line, replace Ust’ Kamchatka with: Ust’? Kamchatsk. Generous Donation from the Conchologica! Club of Southern California A VERY GENEROUS DONATION to the Endowment Fund of the C. M. S., Inc. was received from the Conchological Club of Southern California, for which we express our thanks. We cannot stress enough how important such donations are for the continued existence of our journal, nor can we express how much they do encourage us in our continuing efforts to make the Veliger better and bigger, issue by issue. Again, many thanks to our Friends of the C. C.S. C. UNITAS MALACOLOGICA The Seventh International Malacological Congress will be held from 31 August to 6 September 1980 at Perpignan and Banyuls-sur-Mer in France. With the change from Unitas Malacologica Europaea to Unitas Malacalogica, membership is now open to all scientists interested in all topics concerning mollusks. Papers may be presented at the Congress in English, French or German; any topic about living or fossil mol- lusks will be welcome. The international malacological journal, Malacologia, will, as in the past, publish abstracts of the papers presented. Dr. Jean M. Gaillard, of the Muséum Nationale d’His- toire Naturelle, 55 Rue de Buffoon, F — 75005 Paris, is President, Dr. Oliver E. Paget, Naturhistorisches Museum Wien, Austria, is Secretary and Dr. Peter Jung, Natur- historisches Museum Basel, Switzerland, is Treasurer. Further information may be obtained from the Secre- tariat for the 1980 Congress, Laboratoire B. I. M. et Malacologie, 55 Rue de Buffon, F — 75005, Paris, France. For membership, applications may be sent to Dr. Paget, Naturhistorisches Museum, Burgring 7, A — 1014, Vienna, Austria. Vol. 21; No. 3 Sale of C. M. S. Publications: Effective January 1, 1978, all back volumes still in print, both paper covered and cloth bound, will be available only from Mr. Arthur C. West, P. O. Box 730, Oakhurst, CA (lifornia) 93644, at the prices indicated in our Notes and News section, plus postage and, where applicable, California State Sales Tax. The same will apply to the Supplements that are still in print, except for supplements to vol. 7 (Glossary) and 15 (Ovulidae), which are sold by The Shell Cabinet, P O. Box 29, Falls Church, VI (rginia) 22046; and supplement to volume 18 (Chitons) which is available from Hopkins Marine Station, Pacific Grove, CA (lifornia) 93950. Volumes 1 through 8 and 10 through 12 are out of print. Volume 9: $22.- — Volume 13: $24.- — Volume 14: $28.- Volume 15: $28.- Volume 16: $32.- Volumes 17 to 20: $34.- each. Postage and handling extra. There is a limited number of volumes g, 11, 13, 14 to 20 available bound in full library buckram, black with gold title. These volumes sell as follows: 9 - $27.-; 11 and 13 - $29.- each; 14 and 15 - $33.- each; 16 - $38.-; 17, 18 and 19 - $41.75 each; 20 - $42.25. Supplements Supplement to Volume 3: $6.- [Part 1: Opisthobranch Mollusks of California by Prof. Ernst Marcus; Part 2: The Anaspidea of California by Prof. R. Beeman, and The Thecosomata and Gymnosomata of the Calli- fornia Current by Prof. John A. McGowan] [The two parts are available separately at $3.- each] Supplement to Volume 6: out of print. Supplement to Volume 7: available again; see announce- ment elsewhere in this issue. Supplement to Volume 11: $6.-. [The Biology of Acmaea by Prof. D. P. Assotr et al., ed. Supplement to Volume 14: $6.-. [The Northwest American Tellinidae by Dr. E. V. Coan] Supplement to Volume 16: $8.-. [The Panamic-Galapagan Epitoniidae by Mrs. Helen DuShane] Orders for any of the publications listed above should be sent directly to Mr. Art West. If orders are sent to us, we will forward them. This will necessarily result in delays. THE VELIGER Page 403 A Glossary of A Thousand-and-One Terms Used in Conchology by Wintrrep H. ARNoLD originally published as a supplement to volume 7 of the Veliger has been reprinted and is now available from The Shell Cabinet, Post Office Box 29, Falls Church, Virginia 22046, U.S. A. The cost is US$ 3.50 postpaid if remittance is sent with the order. Supplement to Volume 15: Our stock is exhausted, but copies are still available from The Shell Cabinet, P. O. Box 29, Falls Church, Virginia 22046. [A systematic Revision of the Recent Cypraeid Family Ovulidae by Crawrorp Neti Cate] Other supplements: [Growth Rates, Depth Preference and Ecological Succes- sion of Some Sessile Marine Invertebrates in Monterey Harbor by Dr. E. C. Haderlie] Supplement to Volume 17: Our stock of this supplement is exhausted. Copies may be obtained by applying to Dr. E. C. Haderlie, U. S. Naval Post-Graduate School, Mon- terey, CA(lifornia) 93940. Supplement to volume 18: $10.50 postage paid. [The Biology of Chitons by Robin Burnett et al.]. (Our supply of this supplement is exhausted; however, copies may be available by making application to the Secretary, Hopkins Marine Station, Pacific Grove, Cali- fornia 93950.) WE ARE PLEASED to announce that an agreement has been entered into by the California Malacozoological Society, Inc. with Mr. Steven J. Long for the production and sale of microfiche reproductions of all out-of-print editions of the publications of the Society. The microfiches are available as negative films (printed matter ap- y of it 4 . ~ it — . S t y + Mag UK saa <> ‘ % , a ie ~ Vol. 21; No. 4 That integration of these layers is admirably served is attested by the firmness with which the periostracum coheres to the shell. The height and prominence of major tubercles, and the depth to which they penetrate the periostracum, is probably a function of the relatively thick periostracum. By contrast, HammLTon (1969) re- ported that the mosaicostracum in individuals in the family Tellinidae is relatively thin, only about 0.3 um thick; this may be the result of the thin periostracal layer usually encountered in these species. The configuration and height of tubercles in M. edulis probably not only effectively cement the periostracum to the prismatic layer, but also prevent the periostracum from sliding over the shell when pressure is applied. This feature is an advan- tage to an organism that, in close juxtaposition to its neighbors, often lives exposed intertidally to the pounding of waves. Apparently the bond between mosaicostracal and pris- matic layers, both mineralized strata, is adequate for adhesion without additional substructures. When long axes of prisms are positioned at approximately right angles to the surface of the mosaicostracum, interstices among prism ends apparently provide ample crevices for ad- hesion of the mosaicostracum. Prisms lying nearly parallel to the surface (as in Figure 8) also appear to afford suf- ficient variation in contour to provide a firm grip for the mosaicostracum. HamILTon (1969) tentatively grouped and named the patterns of the external surface of the mosaicostracum in the Tellinidae in 5 major categories. None of these pat- terns characteristic of the Tellinidae corresponded with that of Mytilus edulis. This is not unexpected as the fami- lies Tellinidae and Mytilidae are not close taxonomically. The name “tuberculate” is suggested here for the mosaic- ostracal pattern in M. edulis. D’Attitio & RADWIN (1971) named a thin layer on the surface of the valve of several species of 4 families of gastropods, the intritacalx. They noted that in many cases this layer was characterized by an intricate sculpture which did not always correspond to that of the underlying shell, and in many individuals the layer was found under- neath a thin periostracum. It appears that D’Attilio & Radwin’s intritacalx is homologous to Hamilton’s mosa- icostracum. Since the term mosaicostracum was the first proposed, it is used in this paper. None of the intrita- calxal patterns described by D’Attilio & Radwin corre- spond to the mosaicostracal pattern described here for Mytilus edulis, Scanning electron micrographs of the mosaicostracum of Mytilus edulis do not reveal the internal structure of the THE VELIGER Page 413 tubercles or of the basement layer. Study of the organic framework and surfaces of the mosaicostracum in contact with the periostracum and the prismatic zone could be undertaken by cleaving the nacreous stratum from the valves of young mytilids, demineralizing the prismatic- mosaicostracal-periostracal layers, and examining ultra- thin sections of them with the transmission electron micro- scope. In M. edulis the nacreous layer is aragonitic and the prismatic zone is calcitic. In the oyster, Crassostrea virginica (Gmelin, 1791), larval valves and myostracal muscular attachment sites are aragonitic (STENZEL, 1964). In view of the fact that the mosaicostracum in M. edulis serves as an attachment layer for the periostracum, it is possible this layer is also aragonitic. The matter needs investigation. The fact that sonication greatly accelerates dissolution of periostracum when immersed in sodium hypochlorite will provide a useful technique for the comparative study of the mosaicostracum in other groups of mollusks. It is uncertain whether the mosaicostracum is unique to the phylum Mollusca, or whether the layer occurs in other shelled invertebrate groups, such as the Brachiopoda, where a protective outer covering is present. A compara- tive search for the layer in other shelled invertebrates will also be facilitated by the combined use of clorox and sonication. SUMMARY The fine structure of the mosaicostracum, a thin discrete calcareous layer continuous over the outer surface of the valves between the periostracum and the outermost shell layer of bivalves is described for the first time in the bi- valve Mytilus edulis. The layer was exposed for ultra- structural examination by treatment with hydrogen per- oxide and ultraviolet radiation, sodium hypochlorite and sonication, and secretion from the accessory boring organ of the gastropod Urosalpinx cinerea. The exterior surface of the mosaicostracum consists of a finely convoluted tubercular pattern with matching depressions on the un- _ derside of the periostracum. Height of tubercles and cor- responding depressions in the periostracum range from a fraction of a micrometer to 7 um. A thin veneer of mosa- icostracal crystals is deposited over the prismatic layer, ‘appearing to serve as a supporting layer for the tubercles. The configuration and height of tubercles effectively ce- ment the periostracum to the prismatic layer, and pre- vent the periostracum from sliding over the shell when environmental pressures are applied. Page 414 THE VELIGER Vol. 21; No. 4 Literature Cited Cannixer, Mersounne ROMAINE 1978. Ultrastructural analysis of dissolution of shell of the bivalve Mytilus edulis by the accessory boring organ of the gastropod Urosalpinz cinerea. Marine Biol. 48: 105 - 134 D’Armtio, ANTHony @ Groroz E. RaDwIn 1971. The intritacalx, an undescribed shell layer in mollusks. The Veliger 1§ (4): 344-947; 1 plt.; 1 text fig. Grécomer, CHARLES (1 April 1971) 1972. Structure of the molluscan shell. In: M. Florkin a B. T. Sheer (eds.): Chemical Zoology. vol. 7, Mollusca. Acad. Press, New York, N. Y. 7: 45-102; 24 text figs.; 2 tables Hamitton, Grorce H. 1969. The taxonomic significance and theoretical origin of surface patterns on a newly discovered bivalve shell layer, the mosaicostracum. The Veliger 11 (3): 185 - 194; plts. 26-98; 3 tables (1 January 1969) Srenzezt, H. B. 1964. Oysters: composition of the larval shell. 155-156 Swirt, Exiyau 5th Science 145: 1967. Cleaning diatom frustules with ultraviolet radiation and per- oxide. Phycologia 6 (2/3): 161 - 163 Explanation of Figures 7 to 12 Figure 7: Enlarged view of portion of exterior surface of mosaic- ostracum of Mytilus edulis exposed by treatment with clorox for 18 minutes and sonication for 12 minutes (which dissolved the peri- ostracum), illustrating highly irregular tubercular shapes of crystals. Combined clorox and sonication treatment smooth tops of major tubercles slightly (compare with Figure 5). Scanning electron micrograph. Scale bar = 5 um Figure 8: Exterior surface of mosaicostracum treated only with clorox for 40 hours. Tubercles of mosaicostracum (m) affixed to prismatic layer (pr). Treatment did not dissolve all of periostracum (p) and remnants of it are visible at upper left. Scanning electron micrograph. Scale bar = 1.74m Figure 9: Oblique view of fracture section of shell from which periostracum was removed by immersion in clorox for 10 minutes and sonication for 5 minutes, dissolving all periostracum. Prisms of prismatic region visible in fracture surface (pr), next left is smooth surface of fractured mosaicostracal crystals (mf), and to left of this is tubercular surface of mosaicostracum (m). Scanning elec- tron micrograph. Scale bar = 2.5 um Figure 10: Exterior surface of mosaicostracum after shell frag- ment treated with clorox for 2.75 hours and sonicated for 65 minutes to remove periostracum, showing rows of major tubercles and successively smaller tubercles between the major rows. Exposed tops of tubercles were smoothed of sharp projections by treatment (compare Figures 5, 7, 9). Scanning electron micrograph. Scale bar = 24m Figures 11-12: Edge of bore hole (B) excavated by the gastropod Urosalpinx cinerea follyensis Baker, 1951 in shell of Mytilus edults at spot where periostracum peeled back from mosaicostracum dur- ing drying. Figure 11. Intact mosaicostracal tubercles (m) at left and tubercies partly dissolved by secretion of accessory boring organ of U. cinerea at right (d). Figure 12: Normal undersurface of periostracum (p) at right and periostracum partially dissolved by secretion at left (d). Scanning electron micrograph. Scale bar = 5 am Tue VELIcER, Vol. 21, No. 4 [CarrikER] Figures 7 to 12 Vol. 21; No. 4 THE VELIGER Page 415 The Digestive Diverticula of Alderia modesta and Elysia chlorotica ' (Opisthobranchia : Sacoglossa ) BY DEBRA A. GRAVES, M. A. GIBSON anp J. 8. BLEAKNEY Department of Biology, Acadia University, Wolfville, Nova Scotia, BoP 1X0 (3 Plates; 5 Text figures) INTRODUCTION THE MAJORITY OF ADULT sacoglossans are green in colour and a number of authors (KawacuTI & YAMASU, 1965; Taytor, 1968; TrENcH et al., 1969) have shown that this coloration is attributable to ingested chloroplasts. Long-term associations between active algal chloroplasts and the digestive cells of sacoglossans appear to be re- stricted to the siphonaceous algae (Order Siphonales) and the elysioid sacoglossans (TRENCH, 1975). The eoli- diform (cerata-bearing) sacoglossans, on the other hand, apparently retain chloroplasts for shorter time periods, often of less than 24 hours (HiNDE & SmiTH, 1974; Mc- Lean, 1976). Elysia chlorotica (Gould, 1870) has not been examined for intracellularly functional chloroplasts but other species of the genus Elysia do retain functional chloroplasts (Tay- Lor, 1968; TrENcH et al., 1969; GREENE, 1970; and TreNncH ¢é al., 1973). Alderia modesta (Lovén, 1844) has been reported not to retain functional chloroplasts (Hinve « SmitrH, 1974). In Nova Scotia the alga con- sumed by both E. chlorotica and A. modesta is an unde- termined species of Vaucheria which forms fuzzy mats upon the salt marsh in summer and in winter occurs as a filamentous aquatic form in the numerous marsh pools. Both slugs occur in both habitats (Bamezy «& BLEAKNEY, 1967; BLEAKNEY & BatLey, 1967). As Vau- cheria chloroplasts (Order Xanthophyta) have never been reported as establishing symbiotic associations with sacoglossans, the local situation provides an opportunity for a comparative morphological and functional study of two sympatric elysioid and eolidiform sacoglossans feeding on the same algal species. The situation is com- parable to European investigations of the elysioid E. viridis (Montagu, 1804) and the eolidiform Placida den- dritica (Alder & Hancock, 1843) feeding on the siphon- t Supported by the National Research Council of Canada aceous alga Codium (TrENcH, 1975; McLean, 1976). Thus, the purpose of this paper is twofold: (1) to pro- vide a description and comparison of the structure of the digesive diverticula of Alderia modesta and Elysia chlor- otica using light and electron microscope techniques, and (2) to assess the photosynthetic capabilities of chloro- plasts of Vaucheria in E. chlorotica and A. modesta by studying light-mediated oxygen production. MATERIALS anp METHODS Specimens of Alderia modesta and Elysia chlorotica were collected from salt marshes of the Minas Basin, King’s County, Nova Scotia. They were found in trenches and pools dominated by algae of the Cladophorales and on Vaucheria sp. mats in damp depressions at the base of Spartina alterniflora. Specimens were maintained in re- frigerated jars of sea water or in an aerated salt water aquarium. For histological study, tissues were fixed in Zenker’s fixative, paraffin embedded and sectioned at 7 um. The sections were stained with either Ehrlich’s hematoxylin and alcoholic eosin Y (THompson, 1966) or with Mal- lory’s trichrome sequence (LILurE, 1965). Several histochemical tests were used. Glycogen was demonstrated in Rossman’s fixed, paraffin embedded tis- sues with the periodic acid Schiff’s reaction (PAS) of Hotchkiss as described in THompson (1966). Companion sections were digested with diastase to distinguish the glycogen from other PAS-positive substances. Ribonucleic acid (RNA) was demonstrated in Carnoy’s fixed tissues with the methyl green-pyronin Y method of Brachet. To confirm the identification of RNA, control sections were digested with bovine ribonuclease for 24 h before staining. Lipids were visualized in tissues fixed in either 10% for- malin or in Baker’s formol calcium, gelatin embedded, and sectioned at 10 um on a freezing microtome at —-20°C. Page 416 Two neutral lipid methods were used, the oil red O meth- od of Lillie and the propylene glycol-Sudan method of Chiffelle & Putt. Acid mucopolysaccharides were inves- tigated in Zenker’s fixed and paraffin embedded tissues. The Alcian blue method, staining at pH 2.5 for 30 min., as described by HumMason (1972) was used. The Gomori method (Humason, op. cit.) was used to demonstrate acid phosphatase. Tissues were fixed in Baker's formol calcium, gelatin embedded, and sectioned on a freezing microtome at —20°C. An incubation time of 4 h at 37°C was used. Control sections were incubated in a substrate medium containing sodium fluoride to inhibit enzyme activity. Gomori’s calcium-cobalt method was used to demonstrate alkaline phosphatase activity. The tissues were fixed in 80% ethanol at 4°C and paraffin embedded. An incubation time of 4 h at 37°C was used. Control sec- tions were prepared in an identical manner except that the sodium glycerophosphatase was omitted from the in- cubation medium. Calcium was demonstrated in Carnoy’s fixed, paraffin embedded tissues with the alizarin red S method of Dahl. Unless other references are given, the above techniques were applied as described by PrarsE (1961). For electron microscope studies, tissues were fixed in 2.5% glutaraldehyde in filtered sea water, post-fixed in 1% osmium tetroxide in filtered sea water, and embedded in Durcupan. For orientation, thick sections were stained with 1% aqueous toluidine blue —- 1% aqueous borax solution. The thin observational sections were stained with uranyl acetate and Reynold’s lead citrate (PEasE, 1964) and studied with a Zeiss EMoS electron microscope. Oxygen production was used as a criterion to measure photosynthetic activity in Elysia chlorotica and Alderia modesta. A Beckman oxygen macroelectrode attached to a DC Null Voltmeter and a chart recorder was used. Specimens were placed in a 1omL flask of filtered sea water containing an autonomic stirrer. The tests were con- ducted in an Econaire Growth Chamber which provided THE VELIGER Vol. 21; No. 4 a uniform temperature of 23°C and even illumination on all sides. The specimens were exposed to varying time periods (recorded in Figures 3 and 4) of light and dark and 0.9 g of Elysia chlorotica and 0.06 g of Alderia modes- ta were used. As an additional test of photosynthetic activ- ity, inhibition of O, production was attempted by adding 3(3,4-dichlorophenol)-1, 1-dimethylureaa (DCMU) (4 X 10% mol I") to the Elysta chlorotica flask. To compare overall pigment contents, approximately 1 g each of Alderia modesta, Elysia chlorotica, and Vau- cheria sp. was crushed with romL of cold acetone for 15 min. The resulting 3 crude extracts were filtered and the overall absorption spectra determined on a Varian Tech- tron UV-V1S Spectrophotometer. OBSERVATIONS Alderia modesta The digestive diverticula of Alderta modesta branch off the large stomach and pass dorsally into the cerata and ventrally into the foot region. These digestive tubules are lined with epithelium supported by a thin layer of con- nective tissue. Smooth muscle bundles also envelop the tubules. A basement membrane was not observed. Chloro- plasts are frequently present in the lumina of the tubules. With light microscope techniques, two cell types form the epithelial lining (Figure 6). Cell type AI (Alderia 1) is large and granular, whereas cell type AII (Alderia IT) is small and non-granular. Cell AI is the more numerous and forms the lining of much of the tubule. With the hematoxylin and eosin and Mallory’s methods, cell AI contains clear vacuoles and acidophilic granules while cell AII stains basophilically. Histochemically, both celis stain positively for glycogen, RNA, neutral lipids and both cells stain negatively for acid mucopolysaccharides and calcium. Acid phosphatase is present along the luminal Explanation of Figures 6 to 11 Figure 6: Digestive tubule of Alderia modesta showing cell types AI and AII. Toluidene Blue O. X 1500 Figure 7: Digestive tubule of Elysia chlorotica showing cell types EI and ETI. Toluidene Blue O. X 1500 Figure 8: Digestive tubules of Elysia chlorotica showing staining reaction for neutral lipid. Oil Red O. Figure g: Digestive tubules of Elysia chlorotica showing staining A315) reaction for alkaline phosphatase. Gomori’s method. X 375 Figure 10: Digestive tubules of Elysia chlorotica showing staining reaction for alkaline phosphatase along the luminal border. Gomori’s method. X 375 Figure 11: Digestive tubules of Elysia chlorotica showing staining reaction for calcium (arrows). Note cell EI is negative and cell EI] is positive. Alizarin. X 600 [Graves, Gregson & BLEAKNEY] Figures 6 to 11 Tue VE icER, Vol. 21, No. 4 Vol. 21; No. 4 border of both cell types. These staining reactions are summarized in Table 1. Table 1 Staining affinities of the cell types in the digestive diverticula of Alderia modesta and Elysia chlorotica. Cell Types Staining Technique Alderia Alderia Elysia Elysia modesta modesta chlorotica chlorotica AI All EI EI PAS * * * * methyl green-pyronin Y = ys o is oil red 0 . * * * propylene glycol S * * * Alcian blue — = = a alizarin red S$ _ = = * acid phosphatase - = * = alkaline phosphatase = oo ** ed — no reaction * some reaction ** strong reaction At the electron microscope level, the most diagnostic components of cell AI (Figures 1 and 12) are the hetero- genous bodies. The heterogenous bodies are generally found in the apical half of the cell, each is encircled by a membrane, and each contains granules which may be loosely to densely packed. Chloroplasts are frequently ob- served in these cells. When present, they are surrounded by an extrinsic membrane and show varying degrees of degradation. Small vesicles are often found close to the chloroplasts and heterogenous bodies. Lipid inclusions are common, vary in size, and often are surrounded by hetero- genous bodies. These cells have long or oval mitochondria, a rough endoplasmic reticulum usually located along the cell periphery and around the cell organelles, and a nuc- leus which frequently contains a rod-shaped crystal. Mi- crovilli and many small vesicles are found along the luminal border and cilia are occasionally present. Cell AII (Figures 1 and 19) is usually observed in the basal half of the epithelial lining. It contains long thin mitochondria, small vesicles, and glycogen. Concentric layers of smooth endoplasmic reticulum are prominently distributed throughout the cell. Lipid inclusions coupled with clear vesicles, vesicles containing material with a dense core, and cytoplasmic lattice-work crystals are pres- THE VELIGER Page 417 Figure 1 Diagrams of cell types AI and AIT lining the digestive diverticula of Alderia modesta. cp— chloroplasts; cr—crystals; d—dense ves- icles; er — endoplasmic reticulum; h—heterogenous body; | - lipid; Is — lysosome; m — mitochondria; mv — microvillus; n — nucleus ent. The nucleus was not observed to contain crystals. Microvilli are present on those cells which extend to the luminal border. Elysia chlorotica The digestive diverticula of Elysia chlorotica arise from the small stomach as two ducts which immediately sub- divide into many small tubules and ramify throughout the entire animal. Unlike Alderia modesta, E. chloratica does not possess cerata. The tubules are lined with epithelium enveloped only with smooth muscle. A subepithelial basement membrane and connective tissue tunic could not be demonstrated. Unlike A. modesta, the lumina of the digestive diverticula of EZ. chlorotica are characteristically devoid of chloroplasts. At the light microscope level, the epithelial lining con- tains 2 cell types, cell EI (Elysia 1) and cell EII (Elysta II). With the histological techniques used, cell EI is cu- boidal and contains acidophilic granules and cell EII is narrow, non-granular and stains basophilically (Figure 7). Page 418 Histochemically, both cells stain positively for glycogen, RNA, and neutral lipids (Figure 8). Acid mucopolysac- charides could not be demonstrated. Acid phosphatase is present in cell EI (Figure 9). Alkaline phosphatase oc- curs along the lumina! border of both cells (Figure zo). The alizarin red S method demonstrates calcium granules in cell EII (Figure zz) and the Gomori method for al- kaline phosphatase demonstrates extracellular calcium spherules throughout the animal. These staining reactions are summarized in Table 1. At the electron microscope level, cell EI (Figures 2, 14 and 15) contains chloroplasts and cell EII does not. The chloroplasts are distributed throughout the cell and have an average diameter of 5.4 um. They are bounded by an intrinsic double membrane, are composed of paral- lel lamellae and a homogenous matrix containing a few strands of lamellae. Small bodies, possibly oil droplets, may be present between the lamellae. Occasionally, this lamellar structure is not well defined and the chloroplasts appear to be degrading. Lipid inclusions, glycogen, mito- chondria, and smooth endoplasmic reticulum are distrib- uted throughout the cell. Large, often irregular shaped, clear or granular vesicles are occasionally present. The nucleus, often triangular in shape, is located in the apical half of the cell. The luminal border has many microvilli and a few cilia. Numerous small round vesicles, probably pinocytotic vesicles, many containing granules, are dis- tributed throughout the apical cytoplasm and may also be located deeper in the cell. Cell EII (Figures 2 and 75) occurs with the same frequency as cell EI. It is a narrow cell, having the nucleus situated in the apical half. The cytoplasm contains lightly stained granular material. Glycogen, small mitochondria, smooth endoplasmic reticulum, and granular vesicles which are presumably calcium spherules are found through the cell. Occasionally, Golgi bodies are observed. Lipid inclusions are found in the basal region of the cell. THE VELIGER Vol. 21; No. 4 The apical border has microvilli, a few cilia, and sub- jacent small pinocytotic vesicles. Figure 2 Diagrams of cell types EI and EII lining the digestive diverticula of Elysia chlorotice. Abbreviations as in Figure 1 Photosynthesis The tests for photosynthetic activity with Elysta chlorotica show an increase in PO, when the flask was illuminated and a PO, decrease when the flask was darkened (Figure 3). The addition of DCMU to the flask containing E. chlorotica caused a decrease in PO, similar to that caused by the absence of light. Tests using Alderta modesta dem- onstrated that the presence of light did not influence the PO, level in the flask (Figure 4). Explanation of Figures r2 and 13 Figure 12: Digestive tubule of Alderia modesta showing portions of two AI cells containing loosely and densely packed heterogenous bodies (H), degraded chloroplasts (C), lipid (L) within hetero- genous body, mitochondria (M), microvilli (V), small vesicles (S), and pinocytotic activity (P). Uranyl acetate and lead citrate. X 6 120 Figure 13: Digestive tubule of Alderia modesta showing AII cell. Mitochondria (M); endoplasmic reticulum (E); lipid (L) in- clusions coupled with clear vesicles; vesicles containing material with a dense core (D) ; lattice-work crystals (W) ; and nucleus (N). Uranyl acetate and lead citrate. X7 600 Tue VELIGER, Vol. 21, No. 4 [Graves, Gipson & BLEAKNEY] Figures 12, 13 AEE er oe eae ¢ 28 we Vol. 21; No. 4 THE VELIGER Page 419 75 75 ee Dark C) Light xe) 5° 2 # § & £ E 5 g 25 25 15 30 45 60 15 30 45 60 Time (minutes) Figure 3 Graph showing oxygen release by Elysia chlorotica during light and dark periods and following administration of DCMU Pigment Analysis As shown in Figure 5, the crude acetone extracts of Elysa chlorotica and Vaucheria sp. show absorption maxima at 370, 410, 425, 470, 570, 610 and 660 nm. The maxima for Alderta modesta are at 408, 442, 470, and 660 nm, but are not as high nor as distinct as those of E. chlorotica and Vaucheria sp. DISCUSSION HisTOLoGy The digestive tubules of Alderia modesta are lined with epithelium supported by connective tissue and smooth muscle layers. A basement membrane was not observed. Time (minutes) Figure 4 Graph showing oxygen release by Alderia modesta during light and dark periods The epithelial lining of Elysia chlorotica is surrounded by a smooth muscle layer, but no basement membrane or connective tissue layer was observed. The subepithelial layer of E. viridis contains a thick basement membrane and connective tissue layer (Taytor, 1968), while that of E. atroviridis has a thick basement membrane and both connective tissue and muscle layers (KawaGuTI & YAMA- Su, 1965). The lumina of the diverticula of E. chlorotica are devoid of chloroplasts. A similar observation has been reported for E. viridis (TrencH et al., 1973). The lumi- na of Alderia modesta, on the other hand, characteris- tically contains chloroplasts. This suggests that A. modesta feeds regularly, whereas E. chlorotica feeds only sporadi- cally, obtaining energy from the photosynthetic activity of its intracellular chloroplasts. The digestive diverticula of Alderia modesta are lined by 2 epithelial cell types. Cell AI is the larger, is more Page 420 THE VELIGER Vol. 21; No. 4 rb hay a al Ont Bi fa b! QO | ae | o & < | o | fa | a o } ie H i i | {| i 350 400 450 500 a: Vaucheria sp. b: Elysia chlorotica c: Alderia modesta 550 600 650 700 75° Wave Length in Nanometers Figure 5 The absorption spectra of crude acetone extracts from tissues of Vaucheria sp., Elysia chlorotica and Alderia modesta numerous, and possesses a granular cytoplasm. It is sug- gested that this cell has a digestive function because it stains positively for acid phosphatase, an enzyme associ- ated with lysosomes. Also, the luminal border stains in- tensely for alkaline phosphatase, indicating the presence of microvilli and suggesting a border which is active in transport. Ultrastructurally, this cell contains chloroplasts in various stages of degradation surrounded by an animal cell membrane, presumably a phagosome. MuscarTINE et al. (1975) proposed that chloroplasts within vacuolar membranes are subject to hydrolysis by lysosomes, where- as symbiotic chloroplasts occur free in the sacoglossan Explanation of Figures 74 and 15 Figure 14: Digestive tubule of Elysia chlorotica showing EI cell with intact chloroplasts (C); glycogen granules (G); lipid inclusions (L); mitochondria (M) ; irregularly shaped vesicles (I); micro- villi (V); and small vesicles along luminal border (S). Uranyl acetate and lead citrate. X 6 120 Figure 15: Digestive tubule of Elysia chlorotica showing EII cell between two EI cells. Glycogen (G) ; mitochondria (M) ; granular vesicles or lime spherules (R) ; lipid (L); microvilli (V) ; and small vesicles along luminal border (S). Uranyl acetate and lead citrate. 7 200 [Graves, Gipson « BLEAKNEY] Figures 14, 15 Tue VELIcER, Vol. 21, No. 4 Vol. 21; No. 4 digestive cell cytoplasm and are thereby protected from enzymatic degradation. During degradation, chloroplasts of A. modesta lose their original shape and the lamellae become indistinct. Often small vesicles are associated with the chloroplasts. The heterogenous bodies, typical of the Al cell, are possibly vesicles of chloroplast digestion. Some of the small vesicles associated with both the chloroplasts and the heterogenous bodies may be lysosomes. Others may be pinocytotic vesicles from the luminal border. Presum- ably, phagocytosis also occurs as chloroplasts are often observed under the luminal border. However, the process of phagocytosis as described by McLrEan (1976) for an- other eolidiform sacoglossan, Placida dendritica, was not seen. Cell AIT is smaller and less numerous than cell AI and, histochemically, it differs from AI in that it does not exhibit a positive reaction for acid phosphatase. At the electron microscope level, cell AII contains some distinct inclusions: vesicles having a dense core, lattice-work crys- tals, and an extensive endoplasmic reticulum. The func- tion of this cell is unknown. However, the extensive endo- plasmic reticulum and the pinocytotic or endocytotic ac- tivity of the luminal border indicate a very active cell. Also, the intense alkaline phosphatase activity along the luminal border indicates active transport. Thus, it appears that this cell is either secreting into the lumen or seques- tering substances from the lumen. The epithelial lining of the digestive diverticula of Elysia chlorotica also has 2 cell types, cell EI and cell EII. Cell EI is cuboidal in shape and contains acidophilic granules. FRETTER (1940) reported a cell showing a sim- ilar histology in E. viridis except that the cell she de- scribed contained vacuoles of yellowish or brown material which she suggested were excretory masses derived from the digestion of food. Taytor (1968) also described the granular cells in E. viridis which contained the excretory masses. The cell in E. viridis contains acid mucopolysac- charides, otherwise it is histochemically similar to the one reported in the present study. It is suggested that cell EI is digestive in function as it exhibits an intense acid phos- phatase reaction indicating the presence of lysosomes, and an intense alkaline phosphatase reaction along the luminal border indicating active transport. The presence of microvilli and pinocytotic vesicles supports this sug- gestion. Fretter and Taylor also refer to this cell type in E. viridis as a digestive cell. At the electron microscope level EI of Elysia chlorotica is comparable to the digestive cell of E. viridis as de- scribed by Taytor (1968). However, certain differences are evident. The chloroplasts of E. chlorotica differ in size and structure from those of E. viridis. Those in E. chlor- otica possess a lamellar structure and a region of homo- THE VELIGER Page 421 genous matrix containing a few strands of lamellae. They have a mean diameter of 5.4m. Only the chloroplast envelope was observed, which supports the conclusions of Muscatine et al. (1975) that active chloroplasts are in direct contact with the host’s cytoplasm and that only defunct chloroplasts in Elysia spp. become enveloped by autophagic host vacuoles. The chloroplasts of E. viridis, from the siphonaceous alga Codium fragile, are 2 - 3 um in diameter and possess a lamellar structure of double disc bands, oil droplets and a discoidal starch grain. The large clear digestive vacuoles of E. viridis are not present in E. chlorotica. However, numerous lipid inclusions are present and are large and lightly stained. Cell EII is a long narrow cell, less common than cell EI, and stains basophilically. This cell stains positively for calcium and appears to be similar to the lime cell in Elysia viridis described by Taytor (1968) which is also positive for calcium. Both FrReTTER (1940) and TayLor (op. cit.) suggest that this cell type may have a buffering function. At the electron microscope level, the lime cells of E. chlorotica and E. viridis appear to be similar. Both cells lack chloroplasts and contain electron dense lime vesicles. The large lipid inclusions found in the basal region of the E. chlorvotica lime cell are comparable to the large vacuoles often found in the lime cell of Z. viridis. Pinocytotic or endocytotic activity is present along the luminal border of the lime cells in both species. Thus, at the electron microscope level, the 2 cell types in Elysia chlorotica correspond closely with the digestive and lime cells of E. viridis as reported by TayLor (1968). Photosynthesis Studies of O, production undertaken to test Elysia chloro- tica’s capacity for photosynthesis showed that these ani- mals are capable of producing an increase in the PO, of the surrounding water when supplied with sufficient light. This major increase in the water PO, to the level of saturation of the chamber and consequent formation of O, bubbles, could only be caused by photosynthesis of chloroplasts in the digestive cells. The PO, levels in the flask containing Alderia modesta were not influenced by light, indicating that the chloroplasts of A. modesta are not photosynthetically active. This is in agreement with Hinpe & SmirH (1974). Pigment Analysis Spectral analysis of the acetone-extracted pigments re- veals that the absorption maxima of Elysia chlorotica and the alga Vauchena sp. are the same, indicating that Vau- cheria sp. is the food plant of E. chlorotica. Although Al- Page 422 THE VELIGER Vol. 21; No. 4 deria modesta is known to eat Vaucheria sp. (EVANS, 1953) and is found on Vaucheria sp. in the Minas Basin region, the absorption maxima of A. modesta are similar but not identical to those of Vaucheria sp. This indicates that chloroplast pigments are broken down soon after in- gestion. HInDE & SmirH (1974) reported that chlorophyll degradation is probably rapid in A. modesta. SUMMARY Although Alderia modesta and Elysia chlorotica occupy similar habitats and feed on the same alga, they differ with respect to the structure of their digestive diverticula and their mode of nutrition. The majority of the cells lining the diverticula of A. modesta are involved with rapid degradation of the algal cell contents, including chloroplasts, whereas much of the epithelial lining of the diverticula of E. chlorotica is involved with the long term retention of photosynthetically active chloroplasts. This discovery of active chloroplasts of Vaucheria sp. in the digestive cells of Elysia chlorotica is the first evi- dence of a symbiotic relationship between an elysioid saco- glossan and an alga of the Order Xanthophyta. Literature Cited Bartey, Kaniautono H. « J. S. BLEAKNEY 1967. _‘ First Canadian report of the sacoglossan Elysia chlorotica Gould. The Veliger 9 (3): 353 - 354 (1 January 1967) Buzaxney, J. S. a Kaniautono H. Battey 1967. Rediscovery of the salt marsh sacoglossan Alderia modesta Lo- vén in eastern Canada. Proc. Malacol. Soc. London 37: 347 - 349 Evans, T. J. 1953- The alimentary and vascular systems of Alderta modesta Lovén in relation to its ecology. Proc. Malacol. Soc. London 29 (6): 249 to 256; 5 text figs. Fretter, VERA 1940. On the structure of the gut of the sacoglossan nudibranchs. Proc. Zool. Soc. London 110: 185 - 189; 2 text figs. Greene, Ricwarp W. 1970. | Symbiosis in sacoglossan opisthobranchs: symbiosis with algal chloroplasts. Malacologia 10 (2): 357-368; 7 text figs. (10 July 1971) Hinve, Rosauinp & Dav C. §uitH 1974. “Chloroplast symbiosis” and the extent to which it occurs in Sacoglossa, Biol. Journ. Linn. Soc. 6: 349 - 356; 7 text figs. Humason, GretcHen L. 1972. Animal Tissue Technique. cisco. 641 pp. Kawacutt, Siro & TERUFUMI YAMASU 1965. Electron microscopy on the symbiosis between an elysioid gastro- pod and the chloroplasts of a green alga. Biol. Journ. Okayama Univ. 11 (3-4): 57-65; ro text figs. Livug, R. D. 1965. Histopathologic Technic and Practical Histochemistry. 3rd. ed. McGraw-Hill, New York, 715 pp. McLegav, N. 1976. Phagocytosis of chloroplasts in Placida dendritica (Gastropoda : Sacoglossa). Journ. Exp. Zool. 197: 321 - 330 Muscatine, L., R. R. Poot a R. K. Trencw 1975. Symbiosis of algae and invertebrates: aspects of the symbiont surface and the host-symbiont interface. Trans. Amer. Micros. Soc. 94 (4): 450-469 Pearse, A. G. EvERSON 1961. Histochemistry, Theoretical and Applied. Ltd., London, 998 pp. Pease, Danier C. 1964. Histological Techniques for Electron Microscopy. Acad. Press, New York. 381 pp. Taytor, Dennis L. 1968. Chloroplasts as symbiotic organelles in the digestive gland of Elysia viridis (Gastropoda, Opisthobranchia). Journ. mar. biol. Assoc. U. K. 48: 1-15; 3 text figs. THOMPSON, SAMUEL W. 1966. Selected Histochemical and Histopathologica] Methods, Charles C. Thomas, Springfield, Ill. 1639 pp. Trencu, Rosert K. 1975. Of “leaves that crawl”: functional chloroplasts in animal cells. Soc. Exp. Biol. Cambridge Sympos. 29: 229 - 266; 19 plts.; 10 text figs. TrencH, Robert K., Richarp W. Greene & Barsara G. BysTrom 1969. Chloroplasts as functional organelles in animal tissues. Journ. Cell. Biol. 42 (2): 404-417; 11 text figs. TrencH, Rosert K., J. EvizaBETH Boye & Davip C. SuitH 1973. The association between chloroplasts of Codium fragile and the mollusc Elysia viridts II. Chloroplast ultrastructure and photosynthetic carbon fixation in E. viridis. Proc. Roy. Soc. London B. 184: 6g - 81; 19 figs. W. H. Freeman Co., San Fran- J. & A. Churchill, Vol. 21; No. 4 THE VELIGER Page 423 Notes on the Reproductive Strategies of the South African Vermetid Gastropods Dendropoma corallinaceum and Serpulorbis natalensis ROGER N. HUGHES Department of Zoology, University College of North Wales, Bangor, Gwynedd LL57 2UW, United Kingdom INTRODUCTION THE PRESENT PAPER discusses the adaptive significance of the reproductive methods employed by Dendropoma corallinaceum (Tomlin, 1939) and Serpulorbis natalensis (Morch, 1862) in the light of new data on juvenile res- piration rates, energy reserves and dispersal capabilities, together with the general biological information on these species described in Hucues (1978a, 1978b). Dendropoma corallinaceum is a dominant organism of exposed rock faces in the cooler waters of the Cape Prov- ince of South Africa, being replaced by a very similar spe- cies, D. tholia Keen & Morton, 1960, in warmer waters from the Transkei northwards. Dendropoma corallinace- um builds sheet-like colonies over the rock surface and on vertical faces the colonies form a zone about 1m wide centred on LWS. Upper limits to this zone are set by des- iccation and lower limits are often set by competition with the limpet Patella cochlear Born, 1778. Serpulorbis natal- ensis has the same geographical distribution as D. coral- linaceum but occurs in loose aggregations beneath stones and on the sides of boulders below LWS in fairly sheltered water. It is replaced by the broadly similar spe- cies S. aureus Hughes, 1978 (HucHes, 1978c) in the Transkei. MATERIALS anp METHODS During August-November 1975, Dendropoma corallina- ceum and Serpulorbis natalensis were kept in the labora- tory, during which time they produced large numbers of young, making it possible to measure juvenile respiration rates and to collect material for subsequent biochemical analysis. From these observations it was possible to esti- mate the energetic cost of the pre-settlement dispersal phase and to compare this with the energy reserves of the newly hatched young. ANIMALS Dendropoma corallinaceum was collected from the up- per edge of the Patella cochlear zone (MLW) at Miller’s Point on the Cape Peninsula. Lumps of the reef-like colo- nies were chipped off the rock face and placed in a well- aerated aquarium at ambient air temperature. Crawling young emerged from the colonies within 24 h but the hatching rate declined over several weeks. The adults survived and sustained normal feeding activities for 4 months. Serpulorbis natalensis were collected from the undersurfaces of stones within 1m below MLW on the southern (lee) side of Schaapen Island, Langebaan. Crawling young emerged within 24 h, continuing to emerge for 2 weeks. The aquarium was cleared of young at 21:00 h and the freshly hatched young that had accumulated by 08:00 h the next morning were collected and placed in the respiro- meter. RESPIROMETRY A Gilson differential respirometer was used. For both species a set of 4 experimental flasks with 2 control flasks was run with KOH as the CO, absorbant. Each experi- mental flask contained 40 Dendropoma corallinaceum or 23 Serpulorbis natalensis in 2 mL filtered seawater. The control flasks were similar to the experimental flasks but lacked animals. The apparatus was kept at 15.5°C, close to the prevailing sea temperature and the flasks were gently shaken. After the animals were introduced, the ap- Page 424 paratus was allowed to equilibrate for 1 h. Readings were then taken every 3 h for a total of 15 h. BIOCHEMICAL ANALYSIS Newly hatched juveniles were fixed in 5% saline forma- lin for transportation to the United Kingdom. The fixed samples of larvae complete with protoconchs were washed in 0.9% aqueous ammonium formate to remove seawater without changing the osmotic pressure, and freeze-dried. They were then comminuted in a vibrating ball mill. Car- bohydrate and lipid contents were determined, as de- scribed previously by HoLtanp & HANNANT (1973). Pro- tein was determined in a sample of the initial aqueous homogenate by the method of Lowry, RosEBROUGH, Farr & RANDALL (1951). Total dry weights were meas- ured individually on a Cahn electrobalance after drying at 60°C for 48 h. Ash contents were weighed after roast- ing at 500°C for 4 h in platinum crucibles. RATES or SINKING In order to test potentiality of juveniles being carried by water currents, the rates of sinking of newly hatched juveniles were measured, using a 40cm column of 38%, seawater at 18°C and a stop-watch. RESULTS RESPIROMETRY Respiration rates remained steady throughout the 15 h experiment with no evidence that O, became limiting. THE VELIGER Vol. 21; No. 4 At the termination of the experiment the young snails were still active and apparently healthy. The O, consump- tion rate corrected to STP was 0.11 mL per individual (4.26+0.25 wL per flask) for Dendropoma corallinaceum and 0.07 iL per individual (1.66+ 0.07 wL per flask) for Serpulorbis natalensis. BIOCHEMICAL ANALYSIS Table 1 shows that about 35% of the total dry weight is due to protein. Carbohydrates account for less than 2% of the total dry weight. Neutral lipid, amounting to about 7- 12% of the total dry weight, is the probable source of energy for the animals. Newly hatched Dendropoma corallinaceum contain 5 ug neutral lipid, which is equivalent to 0.2 J energy (Crisp, 1971). Similarly, Serpulorbis natalensis contains 14.7 wg neutral lipid, equivalent to 0.06 J. Using an energy equivalent of 13.72 Jmg? O, STP liberated as heat dur- ing the catabolism of lipid (ELuiotr & Dawson, 1975), I estimate that D. corallinaceum loses 2.16% 10% J h” as heat and will therefore exhaust its lipid energy reserves in 4-5 days. Serpulorbis natalensis loses 1.37 X10% J h", so that its lipid will last about 18 days. Catabolism of the carbohydrate would sustain D. corallinaceum for a further 5 - 6 h and S. natalensis for a further day. RATES or SINKING Dendropoma corallinaceum has a robust shell that sank at a rate of 3.2cm sec’, S.E. 0.02, n= 5. Serpulorbis — natalensis has a lighter shell and unlike D. corallinaceum is variable in size. The rate of sinking was inversely pro- portional to size, small individuals of 0.7mm shell length Table 1 Biochemical composition expressed as percentage of total freeze dried weight (including shell). Individual total dry weights are the means of 6 replicates. Figures in parentheses are the proportions of total lipid, total carbohydrate and protein in the biochemically extracted material. Individual total dry Ash Neutral Free Free weight content lipid Phospholipid Polysaccharide sugars Protein ug To Yo To % % Dendropoma corallinaceum 7349 55 0.6 0.9 0.1 35.5 newly hatched juveniles (22) (4) (76) Serpulorbis natalensis 126 + 20 50 0.2 1.3 0.3 35.6 newly hatched juveniles Vol. 21; No. 4 sinking at 1.7cm sec’, S.E.=0.01, n=5 and large individuals of 1.4mm shell length sinking at 1.0cm sec", S. E.=0.01, n=5. The above sinking rates were ob- served for animals completely retracted within the shell. The sinking rate is reduced considerably when the animal extends its foot, and is reduced even further when a string of mucus is secreted. Serpulorbis natalensis reduced its sinking rate from 1.7cm sec” with the foot retracted to 0.7cm sec' with the foot extended. The sinking rate with a mucous “drogue” was very variable but was an order of magnitude less than the rates without mucus. DISCUSSION Because of lack of time and equipment, only a few data on respiration rates and very crude data on energy re- serves could be obtained. These data cannot be used as precise estimations but they do enable qualitative deduc- tions to be made about the reproductive strategies em- ployed by Dendropoma corallinaceum and Serpulorbis natalensis. ENERGY RESERVES Lipid is the most efficient form of energy storage where size is limiting, as with the young of most marine inverte- brates. Thus, Hottanp et al. (1975) found that lipid is the major energy reserve of the veligers and developing embryos of Littorina spp. The same has been reported for oyster veligers (HOLLAND & SPENCER, 1973) and bar- nacle cyprids (HOLLAND & WALKER, 1975). The vermetids conform with this trend. DISPERSAL Dendropoma corallinaceum will settle on adult colonies within 24h after hatching but can delay settlement up to 4 days in the absence of suitable substrata. The adult feeding method using a mucous web probably occurs only after the completion of metamorphosis 2 days after settle- ment (HucuHEs, 1978a). These published observations on settlement and the present data on respiration rates and lipid stores both predict that a maximum of 4 - 5 days is available to the juvenile D. corallinaceum for dispersal. Metamorphosis will take a further 2 days, during which time the lipid energy reserve will be virtually exhausted. However, D. corallinaceum tends to settle on Lithotham- nid-type alga that grows over the rocks and over the surfaces of adult colonies. The settling juvenile rasps out a groove in the Lithothamnid to accommodate the grow- THE VELIGER Page 425 ing shell, during which time green faecal pellets are pro- duced. Evidently some of the eroded Lithothamnid is in- gested and may provide supplementary food during meta- morphosis. There are no data on the settlement behaviour of Serpulorbis natalensis. The above estimates are minimal, assuming that lipid is the principal energy source during dispersal and metamorphosis and taking no account of leaching of material during fixation. Carbohydrate is too scarce to be an important energy source and we suppose that protein is nearly all used for growth and enzyme pro- duction, although some energy is probably derived frorn protein catabolism. It is impossible to measure the abso- lute dispersal capabilities of either species in the field, but an indication of their relative dispersal powers can be de- rived from the data at hand. Dendropoma corallinaceum crawls at a speed of 7.4mm minute”, which is twice as fast as S. natalensis (HuGHES, 1978a). The higher activ- ity rate of D. corallinaceum is reflected by its higher respi- ration rate, being about 1.6 times that of S. natalensis. Thus, on a random walk, D. corallinaceum should be able to crawl \/2 times as far per day as S. natalensis. However, S. natalensis has energy reserves sufficient to last 4-5 times as long as D. corallinaceum and so should be capable of crawling much further than the latter species before settlement if suitable substrata are not encountered meanwhile. The probability of any individual reaching a given dis- tance will also depend on the mortality rate and cohort size. Little can be inferred about the mortality rates during dispersal except that Dendropoma corallinaceum lives on exposed shores where there is a danger of being dislodged by wave action, whereas Serpulorbis natalensis lives in calmer water below MLW and is less at risk to this danger. Dendropoma corallinaceum produces a single young per capsule, whereas S. natalensis releases about 24 young per capsule (HuGHEs, 1978a). There is no infor- mation on relative development rates or on the lengths of breeding season (except that D. corallinaceum liberated young in the field during the entire study from July to November) but it seems likely that S. natalensts is much more fecund than D. corallinaceum. So far we have assumed that juveniles disperse by crawling and are therefore limited to distances less than 10m. It is possible that juveniles, having become detached from the substratum by wave action, are carried by water currents over much larger distances, depending on current speed and direction, turbulence and rate of sinking. The observed sinking rates show that Dendropoma corallina- ceum must experience turbulence sufficient to carry even retracted individuals at least tom. Individuals with mu- cous drogues could be kept in suspension for several days and carried distances exceeding 100 or even 1000m, de- Page 426 pending on currents. The sticky quality of the mucus would enhance reattachment should the disseminules be brought against a solid surface. However, the probability of a water-borne juvenile reattaching to a surface suitable for settlement must be very small, so that the majority of D. corallinaceum settling successfully will be those that have dispersed by crawling. Moreover, D. corallinaceum is highly gregarious, juveniles settling on any suitable place immediately outside the grazing ranges of the a- dults. Occasional individuals may succeed at long dis- tance dispersal via water currents to found colonies else- where. The energy reserves will enable water-borne indi- viduals to endure long distance dispersal, whereas quickly settling juveniles may be able to use the stored energy for more rapid metamorphosis and growth. A similar general pattern of dispersal probably holds for Serpulorbis natalensis, except that smaller, looser col- onies are formed. Long distance dispersal by water cur- rents is possibly rarer; the calmer water will make de- tachment and suspension of the juveniles less frequent. In- deed, it is difficult to imagine how juveniles in calm water could become suspended. It is possible that S. natalensis sometimes produces planktonic veligers for long distance dispersal. The variability of hatching size has already been noted. HapFIELD et al. (1972) have shown for several Hawaiian vermetids that embryo size varies considerably within a species or even within single broods and that large embryos that have consumed more yolk from nurse cells hatch as crawling young, whereas smaller embryos that have consumed less yolk may be released as plank- tonic veligers. REPRODUCTIVE STRATEGIES Dendropoma corallinaceum exploits a habitat that is severe because of heavy wave action, but is stable in the sense that environmental conditions remain constant throughout time. By forming continuous sheet-like colo- nies D. corallinaceum has become eminently suitable for exploiting the continually wave-scoured rock faces. With- in its zone, D. corallinaceum is completely dominant, ex- cluding all other species that potentially compete for space. This competitive superiority is achieved by the dense packing of contiguous individuals, which allows al- most the entire surface of the colony to be grazed free of intruding organisms. However, once D. corallinaceum has extended to the limits of its zone, the space available to settling larvae will be confined to those micro-patches on the surface of the colony which are beyond the reach of the grazing adults (grazing occurs sporadically and is used primarily for clearing fouling particles rather than for feeding, which normally makes use of a mucous net). THE VELIGER Vol. 21; No. 4 New patches available for settlement will become avail- able as adults die. Sections through colonies show that most individuals reach adult size, relatively few dying at small sizes. The colony is not built up in layers but increas- es in thickness due to the upward spiral growth of adults and of juveniles that have settled gradually and sporad- ically over the surface of the colony. Space suitable for settling juveniles must be severely restricted and probably becomes available at a slow steady rate. The best strategy under these circumstances is to liberate gradually, over a protracted period, large juveniles that are robust and ad- vanced enough to settle, metamorphose and grow quickly. The production of many juveniles, especially in pulses, would be disadvantageous because most of them would fail to find a vacant settlement site. Moreover, with a fixed parental energy income, the production of more young would reduce their individual size and hence their com- petitive ability. Dendropoma corallinaceum is a good example of a K-selected species (MacARTHUR, 1972) adapted to stable environmental conditions where the population remains close to an equilibrium density and competition (for space) is at a premium. As expected from the theory of r- and K-selection, D. corallinaceum has a protracted breeding season (at least from July to November), relatively low fecundity, but large young. These K-selected attributes are achieved at a cost of lowered potential rate of increase and dispersability. Un- predictable, density-independent mortality does strike D. corallinaceum. Old colonies that have become very thick are weakened and tend to slough off the rock in small patches. The effect is exacerbated by subsequent wave action that erodes the newly exposed edges of the colony. Dispersal to such newly bared rock is well within the capa- bilities of juveniles crawling from the surrounding colo- nies. However, settlement in such bare areas was never recorded in the field, probably because the rocks in the study area were too hard for the juveniles to rasp the shallow groove that is necessary for their successful at- tachment (HucHEs, 1978a, 1978b). Settlement only oc- curs on the surface of colonies or on patches of Litho- thamnion-type calcareous algae that occur both on rocks and among the shells of established colonies. Long dis- tance dispersal would therefore seem relatively unimpor- tant. However, D. corallinaceum has a wide geographical range within which suitable rock faces are often separated by large tracts of unsuitable coastline. Occasional long distance dispersal in water currents must take place and an adequate mechanism for it is provided by the mucous “drogue.” Serpulorbis natalensis forms loose colonies that r -ver monopolise space on the substratum but grow among a large variety of other sedentary organisms. The undersur- Vol. 21; No. 4 faces and sides of stones and boulders no doubt provide a microenvironment that is less stable than the wave-swept rock faces colonised by Dendropoma corallinaceum. Peri- ods of very rough weather, subtle changes in prevailing water currents and deposition of silt, or the encroachment of other sedentary organisms are factors that might cause unpredictable fluctuations in the microenvironment. Competitive ability (for space) can be increased either by forming dense colonies where individuals benefit from the anti-fouling activities of their neighbours (D. corallin- aceum) or by remaining separate from neighbours but growing to a larger individual size (S. natalensis). The dense colonial structure works well in a stable habitat and where microenvironmental quality remains the same over large patches of substratum. In more unstable habitats or on more heterogeneous surfaces, ¢. g., where microen- vironmental quality changes from boulder to boulder or even within boulders, it would be better to have more widely dispersing offspring. The more isolated individuals would then have to depend on size rather than coloniality in the competition for space with other organisms. Larger size allows greater fecundity, which itself would compen- sate for the greater mortality accompanying wider dis- persal. SUMMARY Newly hatched Dendropoma corallinaceum weighed about 37 wg total dry weight (including protoconch) of which 35.5% was protein, 1% was carbohydrate and 7.4% was lipid, suggesting that lipid was an important energy source during the dispersal phase. At 15.5°C (am- bient sea temperature) the crawling young used 0.11 pL O, h™ so that the energy reserves would last 4-5 days. Newly hatched Serpulorbis natalensis weighed about 126 pg total dry weight with a biochemical composition fairly similar to that of D. corallinaceum. At 15.5°C the crawl- ing young used 0.07 uL O, h™ so that the energy reserves would last 18 - 19 days. Dendropoma corallinaceum respired and crawled at twice the rate for a similar sized Serpulorbis natalensis; however, the potential maximum distance crawled prior to settlement may be much greater for S. natalensis, which has larger energy reserves. The majority of juveniles of both species probably disperse by crawling and settle near THE VELIGER Page 427 the parents, but a few may undergo long distance dispersal buoyed up by using water currents and a mucous thread. Dendropoma corallinaceum is a “K-selected” species adapted for high competitive ability in a temporally and spatially predictable environment. Accordingly it pro- duces relatively few, large young over a protracted breed- ing season. Serpulorbis natalensis is a more fecund, wider dispersing species adapted to a more heterogeneous and perhaps less stable environment. ACKNOWLEDGMENTS I thank John Field for his hospitality and for organising my visit to South Africa, Ann for manning the respiro- meter and Dave Holland for undertaking the biochemical analyses. Literature Cited Crisp, D. J. 1971. Energy flow measurements. In: Methods for the study of marine benthos; N. A. Holme & A.D. Mcintyre, eds.: 197-279. IBP Handbook no. 16; Oxford & Edinburgh, Blackwell Scient. Publ. Exuiott, J. M. e W. Davison 1975. Energy equivalents of oxygen consumption in animal energetics. Oecologia (Berlin) 19: 195 - 202 Hoitanp, D. L. « B J. Hannant 1973. Addendum to a micro-analytical scheme for the biochemical analysis of marine invertebrate larvae. Journ. Mar. Biol. Assoc. U. K. 58: 833 - 838 Hottanp, D. L. « B. E. Spencer 1973. Biochemical changes in fed and starved oysters, Ostrea edulis L. during larval development, metamorphosis and early spat growth. Journ. Mar. Biol. Assoc. U. K. 58: 287 - 298 Hottanp, D. L., R. TANTANASIRIWONG & P. J. HANNANT 1975. Biochemical composition and energy reserves in the larvae and adults of four British periwinkles, Littorina littorec, L. littoralis, L. saxatilis and L. neritoides. Mar. Biol. 33: 235 - 2399 Hottanp, D. L. & G. WaLKER 1975. The biochemical composition of the cypris larva of the barnacle Balanus balanoides L. Journ. Cons. int. Explor. Mer 26: 162 - 165 Hucues, Rocer N. 1978a. The biology of Dendropoma corallinaceum and Serpulorbis natalensis, two South African vermetid gastropods. Zool. Journ. Linn. Soc. 64: 1978b. Coloniality in Vermetidae (Gastropoda). In: Biology and systematics of colonial organisms. Spec. Vol. Syst. Assoc. No. 11. eds. G. Larwood « B. R. Rosen, Acad. Press, London & New York 1978c. A new species of Serpulorbis (Gastropoda : Vermetidae) from South Africa. The Veliger 20 (9): 288-291; 4 text figs. : (t January 1978) Lowry, Oxtver Hows, N. J. Rosgsroucu, A. L. Farr « R. J. Ranparr 1951. Protein measurement with the Folin phenol reagent. Journ. Biol. Chem. 198: 265 - 275 MacArtHur, Rosgrt H. 1972. Geographical ecology. Patterns in the distribution of species. Harper & Row, New York, N. Y. Page 428 THE VELIGER Vol. 21; No. 4 Rearing Experiments on the California Market Squid Loligo opalescens Berry, 1911 ROGER T. HANLON, RAYMOND F. HIXON, WILLIAM H. HULET anp WON TACK YANG The Marine Biomedical Institute, University of Texas Medical Branch, Galveston, Texas 77550 (1 Plate; 1 Text figure) INTRODUCTION LoLIGIND SQUDS are important as sources of the giant axon for neurophysiological study (ROSENBERG, 1973) and as fisheries resources (Voss, 1973). Efforts to provide a supply of squids of the genus Loligo by rearing them from eggs have been unsuccessful (ARNOLD, SUMMERS, Gmsert, Manauis, Daw & Lasek, 1974; CHANLEY, 1976). Huriey (1976) succeeded in rearing Loligo opalescens to 13mm mantle length (ML) with Artemia salina as the primary food. Loligo opalescens is large at the time of hatching (Figure 1, top) and presumably is easier to rear than the considerably smaller hatchlings of Loligo pealei (Lesueur, 1821) and L. (Doryteuthis) plei (Blainville, 1823). As part of our investigations on the rearing and maintenance of loliginid squids we were able to rear L. opalescens to a mantle length of 17.3mm prin- cipally on a diet of copepods. This paper summarizes our experience in rearing Loligo opalescens and describes the closed-system seawater a- quaria, food sources and feeding behavior, growth, and causes of mortality. MATERIALS anp METHODS The closed recirculating system consisted of two 64 liter capacity rectangular glass aquaria positioned side by side in a refrigerated water bath. One aquarium was the rear- ing tank while the other served exclusively as a filter to maintain water quality. The filtering tank contained an oyster shell filter bed with a well-established bacterial flora to oxidize nitrogenous wastes. Two auxiliary filters, each containing polyester fiber and activated charcoal, removed particulate debris and dissolved organic sub- stances. Sea water was air-lifted at a rate of 1 to 2 L/min into one end of the rearing aquarium and at the other end it was returned to the filtering tank by siphon. A plankton net partition (105 4m mesh) completely separated the drain siphon from the remainder of the rearing aquari- umand prevented thesquid hatchlings and food organisms from being sucked into the filtering tank. This obstacle- free configuration allowed a slow, even flow of water through the rearing aquarium. Dead food and debris were removed from the rearing tank twice a day, and approximately 3% of the water volume was replaced daily with filtered sea water. An illumination cycle of approxi- mately 12 hours light and 12 hours dark was established with fluorescent light (Westinghouse F96T12 white). ‘Temperature was maintained between 15.0° and 17.0°C, salinity ranged from 34 to 36%, and pH ranged from 7.91 to 8.00. We made observations from a position above the rearing tank several times a day, particularly during feed- ing. Total lengths (TL) of food organisms and mantle lengths of squids were measured and recorded. To avoid damage to hatchlings we measured only freshly dead squids. Using the dead specimens, we calculated a mean growth rate for each animal by dividing the total increase in mantle length by the number of days alive. Squid eggs were collected on 15 November 1976 at a depth of 20m from Monterey Bay, California and were Explanation of Figure 7 Top: Ventral view of the hatchlings of Loligo (Doryteuthis) plei (A) and Loligo opalescens (B). Despite similar adult size, there is a disparity in hatchling size. Bottom: Typical swimming orientation of a 76 day old Loligo opalescens. Arrows indicate fin damage that impaired swimming and was a principal cause of mortality during later stages of the experiment Tue VELIcER, Vol. 21, No. 4 {Haniton, Hixon, Hutet « Yanc] Figure 1 Vol. 21; No. 4 transferred to Galveston, Texas via air (15 hrs) in plastic bags filled with sea water and oxygen. Four experiments were conducted using different foods. Squid hatchlings in Experiments #1 and #2 were fed brine shrimp naup- hii (Artemia salina) exclusively. Wild copepods of vari- ous sizes, brine shrimp nauplii and adults, barnacle naup- lii, larval fishes, and hatchlings of Loligo (Doryteuthis) plei were used in Experiments #3 and #4. The density of food organisms (mainly copepods and Artemia) present in the rearing aquarium on any given day did not exceed I organism/mL. RESULTS No squids survived longer than 10 days in Experiment #1 (80 hatchlings) and #2 (go hatchlings), while 11% of the 80 hatchlings in Experiment #3 survived beyond 10 days, with one squid lasting 35 days. Of the 65 hatchlings of Experiment #4, 15% survived longer than 10 days, with 8% attaining 60 days and 1 individual lasting 79 days. The young squids in these experiments did not feed well on either nauplii or adults of Artemza. When fed exclu- sively on Artemia, none survived longer than ro days. At times, the squids were seen to capture and then reject Artemia. On day 7 of Experiment #3, squids vigorously attacked and ate wild copepods (Labidocera aestiva, 2.9 to 3.5mm TL) collected from Galveston Bay. The young squids learned to maneuver behind and above the cope- pods before attacking in order to avoid the long antennae, thus increasing their catching efficiency. By far the best results were obtained in Experiment #4. The young squids in Experiment #4 initially were fed wild copepods, primarily Labidocera aestiva. The larger blue copepod, Anomolocera ornata (5.0 to 5.4mm TL), was presented on day 19 and was readily attacked and eaten: the remains could be seen in the stomachs of the young squids. This species then became the primary food for rearing. The large transparent copepod, Eucalanus hyalinus (4.0 to 6.5mm TL), was introduced as a sup- plemental food from day 57 to day 66. It was readily attacked and eaten. In addition to these 2 large copepods collected offshore, smaller, unidentified copepods that could not be separated out of the catch, also were eaten throughout the experiment. Artemia nauplii and adults were eaten at times of low availability of copepods, but the squids exhibited a clear preference for cope- pods. During these periods the squids searched the bottom of the tank, and on one occasion a squid was seen to grasp and eat a dead copepod even with live Artemia present. When we added a new supply of copepods, vigo- THE VELIGER Page 429 rous feeding ensued. Nauplii of barnacles Balanus spp. (0.2 to 0.5mm TL) were offered to the squids on days 26 to 32, but no feeding was observed. Two squids at- tacked but could not subdue an unidentified larval fish 14 Dorsal Mantle Length (mm) 10 20 go 40 50 60 70 80 Age (Days) Figure 2 Age and mantle length of 10 young Loligo opalescens raised longer than 10 days and fed a diet of copepods. The dotted lines indicate the range of growth rates of all specimens in the experiments (1.1 to 5.6mm per month). Mean mantle length at hatching was 2.5mm Page 430 times their size on day 53. Subsequently (day 58), the squids ate 2 juvenile guppies (Poecilia sp. between 5 and 8mm TL); however, their interest in them was slight compared to their appetite for copepods. Newly hatched Loligo (Doryteuthis) plei were introduced as food on day 66; the young Loligo opalescens appeared interested but out of 50 observed attacks, 48 were unsuccessful and only 2 hatchlings were captured and eaten. Figure 2 presents the growth data obtained from Ex- periments #3 and #4 in which copepods were the main food source. The largest squid lived 79 days and measured 17.3mm ML. Growth rates of individual squids ranged between 1.1 and 5.6mm ML/month. In general, older animals grew faster, and the lower growth rates were ob- tained from squids less than 40 days old. DISCUSSION Two peaks of mortality occurred: the first between 1 and 1o days, and the second between 60 and 80 days. We believe that some of the early mortality resulted from the failure of hatchlings to learn how to capture prey. Young squids commonly would attack and miss copepods 4 to 7 times before capturing one. The more successful squids avoided the copepods’ sensitive antennae by maneuver- ing above and behind the prey before attacking. We believe that later mortality primarily was due to fin ab- rasion. At approximately day 50 the young squids began to congregate in corners and to bump the clear glass walls of the aquarium. The fins subsequently became ab- raded (Figure 1, bottom), and this impaired their ability to swim and feed. Several days before death each squid was observed motionless on the bottom or swimming erratically, generally unable to feed; one was even suc- cessfully hand fed 2 times. HURLEY (1976) attributed late mortality to the possible dietary inadequacy of Artemia. We believe that the copepads in our experiments provided an adequate diet; however, our supply fluctuated and lower concentrations may have contributed to the late mortality. Various foods have been fed to Loligo opalescens hatch- lings. Fietps (1965) observed no feeding on brine shrimp, newly hatched copepods (Tigriopus fulvus), algae or diatoms; no hatchling survived longer than 10 days and death was attributed to fungal infection. HuRLEy (1976) reported that hatchlings fed upon brine shrimp nauplii and adults‘(0.7 to 5mm TL), copepods (1mm TL), and larval fishes (4mm TL). She also noted that McGowan (personal communication, 1976) observed successful at- tacks on the mysid Metamysidopsis elongata. It is note- worthy that BoLetzKy (1974) reared Loligo vulgaris La- THE VELIGER Vol. 21; No. 4 marck, 1789 (2 to 3mm TL at hatching) to 75 days on the mysid Leptomysis mediterranea with telsons removed to slow their escape. In general, young loliginid squids seem to prefer crustaceans and larval fishes that approxi- mate or exceed their own size. Based upon our results and those of Hurtey (op. cit.) it appears that Artemia is an acceptable, though not preferred food. Despite large fluctuations in copepod availability during our experi- ments, there are indications that growth on a copepod diet was better than with an Artemia diet. The last sur- viving hatchling was 17.3mm ML at 79 days, while Hurzey’s (1976) largest hatchling was 13mm ML at 75 days: Huruey’s (op. cit.: figure 3) mean hatchling size at 82 days was approximately 8mm ML and one hatchling (8mm ML) survived 100 days. The range of individual growth rates during our experiments (1.1 to 5.6mm ML/month, Figure 2) wasslightly higher than the 0.5 to 4.5mm ML/month rates reported by Hurtey (op. cit.). From trawl data on Loligo opalescens reported by Fretps (1965: 78; fig. 52), we calculated a mean growth rate of 7mm/month for the first 3 months post-hatching. For reared squids, only the maximal individual growth rates reported by Hurtey (op. cit.) and ourselves com- pare favorably with the estimated value for wild squids. We suggest that future experiments be conducted in round, large-volume, opaque tanks with adequate water filtration and replenishment. Emphasis must be placed up- on providing a constant supply of live crustaceans such as copepods or mysids of a wide size range, perhaps reared in parallel with the squids. Collecting wild food organ- isms is a time-consuming, costly, and unreliable method, and can be a major limiting factor in squid rearing experi- ments. In all successful rearing attempts on Loligo species thus far, significant mortality occurred at 60 to 80 days. Apart from fin damage, this mortality peak may indicate changing food requirements at this time. We noted in a separate experiment that young, wild-caught Loligo (Do- ryteuthis) plei (12 to 22mm ML) fed aggressively on reared post-larval white shrimp Penaeus setiferus, 15mm TL. Thus, we suggest that post-larval penaeid shrimp and larval fishes may be suitable foods for Loligo opalescens older than 60 days. ACKNOWLEDGMENTS We are most grateful to Thomas E. Sutton and John W, Forsythe for their able assistance in food collection and for maintenance of the system. We thank Ronald Murray for the photograph in Figure 7, bottom, and Deirdre A. McConathy for preparing all the figures. This project was supported in part by Grant No. RR o1024-o01 from the Vol. 21; No. 4 THE VELIGER Page 431 Division of Research Resources, National Institutes of Health and the Marine Medicine General Budget account 4-11500-765111 of the Marine Biomedical Institute, Uni- versity of Texas Medical Branch, Galveston, Texas. Literature Cited ARNOLD, Joun M., Wittiam C. Summers, Danie L. Girpert, RicHaRp S. Manatis, Nice, W. Daw & Raymonp J. Lasex 1974. A guide to the laboratory use of the squid, Loligo pealet. Mar. Biol. Lab. Woods Hole, Mass.; 74 pp.; 17 text figs. BoietTzxy, Siourn v. 1974. Elevage de céphalopodes en aquarium. A): 309 - 340; 9 text figs. Vie et Milieu 24 (2, Cuanrey, Paur 1976. Rearing and maintenance of squid, Loligo pealei. Unpubl. Quart. & Ann. Reprts. (July 1975 to Dec. 1976) to NIH (No. 1-RR- §-2150): 63 pp. Freips, W. Gorpon 1965. The structure, development, food relations, reproduction and life history of the squid Loligo opalescens Berry. Calif. Dept. Fish Game. Fish Bull. 131: 108 pp.; 59 text figs. Hurzey, Ann C. 1976. Feeding behavior, food consumption, growth, and respiration of the squid Loligo opalescens raised in the laboratory. Fish. Bull. 74 (1): 176-182; 3 text figs. RoszensBeERG, PHILIP 1973. The giant axon of the squid: a useful preparation for neuro- chemical and pharmacological studies. PP. 97-160; 21 text figs. In: R. Fried, ed. Methods of neurochemistry. Vol. 4. Marcel Dekker, Inc., New York. 332 pp. Voss, Gitpert LINCOLN 1973. | Cephalopod resources of the world. 149: 75 Pp.; 9 text figs. FAO Fish. Circular No. Page 432 THE VELIGER Vol. 21; No. 4 Reproductive Biology of Colus stimpsoni - III (Prosobranchia : Buccinidae) Female Genital System ' DAVID L. WEST * (1 Plate; 6 Text figures) INTRODUCTION THE ORDER Neocastropopa is considered to contain the most advanced prosobranchs, and all its members have internal fertilization (HYMAN, 1967; FRETTER & GRAHAM, 1962). These gastropods deposit their eggs within a resist- ant egg capsule which is attached in clusters or singly to various substrata. Generally, neogastropods deposit many eggs within an individual capsule; whereas, in the majori- ty of other prosobranchs each egg is deposited in an en- casing shell, along with its supply of nutrient albumin. Also, many neogastropods, in which the development has been studied, exhibit suppression of a free living larval stage, and the young emerge as miniature adults. In those species which exhibit direct development, many hundreds of eggs are deposited within a single capsule, but only a few develop. The remaining undeveloped eggs (“nutritive eggs’ or “nurse eggs’) serve as food for the young (THor- SON, 1935, 1940; RADWIN & CHAMBERLIN, 1973; Moore & SANDER, 1978; Lyons & SPIGHT, 1973). With the habits of depositing numerous eggs within a capsule and of internal fertilization, the female genital system has evolved and specialized in accordance with these behaviors (FRETTER, 1941, 1946, 1953). Since fer- tilization must occur before nutritive and capsule forming materials are secreted around the eggs, spermatozoa must be transferred or deposited into the region of the ovi- duct preceding the secretory areas. However, spermatozoa are generally deposited at the terminal end of the female duct. Spermatozoa may be stored at the terminal end, within the bursa copulatrix, or they may be passed up the oviduct and stored within specialized regions connec- ted to the gonoduct, such as the serhinal receptacle or the ingesting gland (FRETTER, 1941, 1953; Houston, 1976). ? Contribution No. 67 from the Marine Science Institute, North- eastern University, Nahant, Massachusetts 2 Present address: Biology Program, Sangamon State University, Springfield, Illinois 62708 Organization of the female neogastropod genital system appears to be rather uniform throughout the order (Pon- DER, 1974; Houston, 1976; SmirH, 1967; FRETTER, 1941, 1946), with differences in the location of the sem- inal receptacle, ingesting gland and bursa copulatrix, or in the presence or absence of some of these structures. The female system generally consists of a single tube ex- tending from the ovary, along the visceral mass, into the mantle cavity where it passes along the roof. In lower gastropods, the ovary is connected to the right nephridi- um, and the gametes are discharged into the water via the nephridiopore. However, in neogastropods the ovary opens into the mantle region by a duct. Various terms, some indicating a functional relation, others having phylo- genetic implications, have been applied to the duct ex- tending along the visceral mass. However, in the present study, the term “rena! oviduct” will be used to denote that portion of the oviduct extending along the visceral mass, and “pallial oviduct” for that portion extending along the mantle roof. The genital ducts of the muricid Thais (Nucella) lapillus (Linnaeus, 1758) and the buc- cinid Buccinum undatum Linnaeus, 1758, are frequently used as examples of neogastropod reproductive systems and are considered typical of this order (HyMAN, 1967; FRETTER & GRAHAM, 1962; PoNnDER, 1974). However, many members of the Buccinidae have not been investi- gated. The present study concerns the female reproductive system of the buccinid Colus stzmpsoni (Morch, 1867) to further the knowledge of its phylogenetic relationships and its relation to the reproductive strategy of direct de- velopment and nutritive eggs. MATERIALS anp METHODS Snails of various sizes were collected intertidally at Cobs- cook State Park, Edmunds, Maine, and at Eastport, Maine, and maintained in running sea water aquaria (WEsT, 1973, 1978). To determine the sex of individual Vol. 21; No. 4 snails, the animals were placed on a dry table with the body aperture facing upward. After a few minutes the snails would try to right themselves. During this period, the presence or absence of a penis cou’d be noted as the foot extended over the edge of the shell. Snails were segregated according to sex, measured, and an identifying number affixed to the shell. For histological studies, tissues were excised from freshly opened snails and processed according to the methods described in the first paper of this series (WEST, 1978). RESULTS General Morphology The ovary, a deep orange-brown to orange-yellow in color, lies on the distal-most portion of the visceral mass in the ultimate and in part of the penultimate whorls of the shell (Figure 1). The ovary and visceral mass are covered by a single layer of cuboidal epithelium, the palli- al epithelium, and a thin layer (20- 60pm thick) of connective tissue and muscle. In large females (80mm or greater in shell length), the ovary may cover more than one-half of the digestive gland. Figure 1 Female Colus stimpsoni: whole animal with shell removed and the mantle drawn as transparent: A — anus; C — columellar muscle; D - digestive gland; K - kidney; OV - ovary; OP -— pallial oviduct; O — renal oviduct THE VELIGER Page 433 The oviduct emerges from the ovary and passes as a single straight duct along the columellar side of the vis- ceral mass beneath the pallial epithelium. At the posterior limits of the mantle cavity, the oviduct turns abruptly dorsad and enlarges. The enlarged portion reflexes anteri- orly and continues in the mantle roof, alongside the rec- tum. The oviduct consists of 2 morphologically distinct portions, a thin-walled renal oviduct which passes along the visceral mass, and a glandular, pallial oviduct which passes along the mantle (Figure 1). The pallial oviduct is opaque white in color and is the most noticeable portion of the genital duct in gross dissection. The pallial oviduct narrows at its anterior end forming a short vagina. In sexually mature females, the pallial oviduct varies from 3 to 6cm in length and is oval in cross section, measuring 5 to 18mm in long axis and 3 to gmm in short axis. Near the junction of the renal and pallial oviducts, at the posterior end of the mantle cavity, a small duct, the gonopericardial duct, opens into the renal oviduct. The gonopericardial duct (Figure 2) passes posteroventrally toward the pericardium. However, this duct could only be traced to within a very short distance from the peri- cardium. Histology Ovary: The ovary is a multitubular organ with the tubules generally oriented perpendicular to the spiral axis of the shell. The ovary is separated from the digestive gland, but ovarian tubes occasionally intrude between the tubules of the digestive gland. Ovarian tubules are sep- arated from one another by a layer (2 - 8 um in thickness) of loose connective tissue and muscle fibers. Beneath this layer is a basal lamina which varies from 0.1 - 0.3 ym in thickness and is composed of a dense layer of fibers. Young oocytes and follicle cells lie on the periphery of the tubule subjacent to the basal lamina. Vitellogenic and postvitello- genic phases of oocyte development occur in the center of the tubule. The ovarian tubules eventually join to form the single oviduct. Renal Oviduct: The thin-walled renal oviduct is em- bedded in loose connective tissue and varies from 500 to 800 um in diameter (Figure 3). The wall (10 to 2ojm thick) is composed of circular muscle and connective tis- sue. The duct is lined with a simple columnar epithelium which rests on an indistinct basal lamina. Epithelial cells vary in height with tall cuneiform cells projecting into the lumen at irregular intervals. These tall cells (75 - 100 zm in height) are surrounded by decreasingly shorter cells Page 434 THE VELIGER Vol. 21; No. 4 Figure 2 Drawing of gonopericardial duct and its relation to the genital duct: C - columelliar muscle; D — digestive gland; GP — gonopericar- with the shortest cells measuring 25 - 30m in height. The variation in cell height gives the epithelium a mucosa- like appearance. Nuclei of the epithelial cells are irregu- lar in outline and vary from 7 -12m in length. Occa- sionally, within the renal oviduct, disrupted oocytes are observed, and the surrounding epithelial cells contain yolk platelets. dial duct; H — heart; K - kidney; OP — pallial oviduct; O —- renal oviduct; VG — visceral ganglion. (Not drawn to scale) Pallial Oviduct: The renal oviduct turns sharply dorsad near the posterior limits of the mantle cavity and becomes glandular, forming the pallial oviduct. The pallial oviduct is composed of 3 parts: a glandular region, a bursa copu- latrix, and the vagina. These components of the oviduct are surrounded by a layer of connective tissue and muscle giving the appearance of a single enlarged tube. Explanation of Figures 6 to 8, zo and 71 Figure 6: Electron micrograph of capsule gland wall showing the dorsal differential-staining region (D) and the central region (C) : B — basal lamina and connective tissue between tubules; N — nuc- leus Figure 7: Electron micrograph of gland cell granules within dorsal and ventral differential-staining regions of the capsule gland Figure 8: Electron micrograph of the gland cell granules within the central region of the capsule gland Figure 10: Egg capsule of Colus stimpsoni: L —- larva; O - capsule operculum Figure 11: Light micrograph of egg capsule wall: C- central layer; I — inner layer; O — outer layer [West] Figures 6 to 8, 70 and 11 Tue VELIcER, Vol. 21, No. 4 Vol. 21; No. 4 Figure 3 Line drawing of a cross section through renal oviduct: B - body wall; L — loose connective tissue Slightly posterior to the transition region between the pallial and visceral portions, the oviduct reflexes sharply posteriad and passes out of the mantle into the body be- tween the kidney and body wall. This portion is parallel and dorsal to the renal oviduct. At a point about 4 along the kidney, the oviduct turns abruptly forward and passes back into the mantle. These turns form an S-shaped loop. This loop is covered by the connective tissue surrounding the pallial oviduct and is not visible in gross dissections, as shown in Figure 2. The glandular segment constitutes the largest part of the pallial oviduct and is histologically similar along its length but has differentially staining regions. The posteri- or end (5 - 1omm in length) corresponds to the albumin gland reported in other neogastropods and the remaining glandular area corresponds to the capsule gland (Fret- THE VELIGER Page 435 TER, 1941; Houston, 1976). In cross section, the albu- min and capsule glands are composed of right and left lobes. These lobes are connected dorsally and ventrally by relatively thin walls which give the lumen of the oviduct the appearance of a dorso-ventral slit (Figure 4). Figure 4 Line drawing of a cross section through the capsule gland; stippled areas show extent of dorsal and ventral differential-staining regions The epithelium of the pallial oviduct consists of tall, ciliated columnar cells (20 - 40 um in height), which have elongated, ellipsoidal nuclei, and numerous gland cells (Fig- ure 5). The gland cells are tightly packed together, form- ing rod-shaped or tubular glands which are elongated and coiled distally. These glands are packed together, and each is enclosed by the basal lamina of the epithelium (Figure 6). Gland cells are large with subspherical, basal- ly located nuclei. These cells are elongated, and the necks of the cells extend to the surface through the center of the gland (Figure 5). The glands have no lumen fer se, but rather a core of cell necks which are filled with secretory granules. While the distal cells of a gland have much longer necks than do the proximal ones, there is no apparent difference in the diameter. Glands along the dorsal and ventral walls of the oviduct are shorter in length (0.3 - 0.5mm vs. 1.5mm) than ones along the lat- eral walls (see Figure 4). Blood lacunae are irregularly distributed throughout the walls of the pallial oviduct and Page 436 appear as numerous, small spaces in sectioned material (Figure 5). Figure 5 Line drawing of capsule gland wall showing tubule glands: B — basal lamina; M — mantle cavity; E — ciliated cells of epithelium; L — loose connective tissue; S — blood sinus. (Not drawn to scale) The albumin and capsule glands stain differentially from one another with the azo-carmine procedure. The granules of the albumin gland cells stain predominantly pale blue; whereas, those of the capsule gland cells stain predominantly purple and pale violet. The albumin gland gives rise to the capsule gland at a region opposite the posterior end of the ctenidium. Near this area, the right dorsolateral wall of the albumin gland forms a fold of glandular tissue. This fold extends ventrally into the lu- men and is attached to the ventral wall at the apex of the fold. This fold is about 5mm in length and is covered laterally with a ciliated epithelium. The fold extends into the posterior limits of the capsule gland and divides the lumen into right and left portions. The capsule gland walls are thicker than the albumin gland walls and have differentially staining areas within them. In cross section, the dorsal 4 and ventral 4 stain predominantly red to purple and the middle section stains predominantly blue to pale violet with the azo-carmine stain (Figure 4). The middle section also stains deep blue- black with Heidenhain’s hematoxylin. Within these re- gions of the capsule gland, the gland cells contain both red and blue staining granules. However, these regions are dominated by one staining type of granule. The gran- ules of the gland cells in the dorsal and ventral portions are predominantly fusiform to rod-shaped (Figure 7) ; THE VELIGER Vol. 21; No. 4 whereas, the granules of the central portion are spherical (Figure 8). The cytoplasm of the cells of the dorsal and ventral portions of the capsule gland is dominated by numerous vacuoles which contain flocculent material, in addition to the dense granules (Figure 7). The granules are electron- dense with alternating bands of slightly less electron den- sities, having a periodicity of about 250 A (Figure 7). The cytoplasm contains a few mitochondria as well as glyco- gen particles and the Golgi complex. The cisternae of the Golgi complex are filled with an electron-dense ma- terial. The granules of the gland cells within the central por- tion of the capsule gland are membrane-bounded and are composed of electron-dense granular material and a some- what less electron-dense fibrous substance (Figure 8). The granular material is distributed in patches broken up by the fibrous material. Well-developed Golgi lamellae are scattered within the cytoplasm, and the cisternae contain an electron-dense granular substance. The cisternae of the rough endoplasmic reticulum are enlarged and con- tain dispersed granules which are about the same electron- opacity as the neighboring cytoplasm (Figure 8). The bursa copulatrix is situated at the anterior end of the capsule gland (Figure g). It is oval in lateral view, and the capsule gland slopes ventrally beneath it. The lu- men of the oviduct passes beneath the bursa copulatrix, opening into the vagina, and the ciliated columnar epi- thelium (20 - 504m thick) of the oviduct is folded in this region. The bursa copulatrix is a muscular chamber and is separated from the capsule gland and the wall of the oviduct beneath it by a layer of loose connective tissue and muscle. The wall of the bursa measures 200 - 500 um in thickness, and the epithelium is ciliated and folded. The duct connecting the bursa copulatrix and vagina is histologically similar to the bursa and is separated from the wall of the oviduct by a layer of loose connective tissue. Sperm fill the bursa copulatrix and its duct throughout the year. Around the periphery of the bursa, the heads of the sperm are oriented toward the epi- thelium and are in contact with it. The duct of the bursa copulatrix opens into the vagina a short distance from the female opening. The vagina is lined with columnar and mucous-secreting cells. Beneath this epithelium is a layer of muscle and connective tissue. The vagina is 5 - 1omm in length and closed by a sphincter (Figure 9). Cytochemistry of Pallial Oviduct Results obtained from sections embedded in polyester wax and stained with Lehmann’s polychrome indicate a num- Vol. 21; No. 4 THE VELIGER Page 437 ber of macromolecular groups are present in the pallial oviduct. The different regions of the capsule gland contain both protein and mucopolysaccharides, and the albumin gland is rich in mucopolysaccharides. The dorsal and ventral portions of the capsule gland are dominated by the presence of an acid or neutral protein. The central portion is dominated by mucopolysaccharides, probably acid in nature. Table 1 records the results of the specific cytochemical tests. Figure 9 Lime drawing of a longitudinal section through posterior portion of the pallia] oviduct: B - Bursa copulatrix; CG - capsule gland wall; L — loose connective tissue; V - vagina. (Not drawn to scale) Table 1 Results of specific cytochemical tests of the pallial oviduct of Colus stimpsoni Capsule gland Albumin Technique gland Dorsal Ventral Central PAS AF + + tee tL Alcian Blue (1.0) = + ae St Alcian Blue (2.3) = + + aL et Bromphenol Blue arate Par ar +++ + +, ++, +++, increasing degrees of positive staining intensity; —, negative reaction Spawning Females deposit egg capsules throughout the year with increased deposition from February to May. Eggs are passed down the oviduct to the albumin gland, where sperm incorporation apparently occurs. During one dis- section, motile sperm were recovered from the posterior part of the albumin gland. The eggs are moved down the pallial oviduct, and secretions from the albumin and cap- sule glands accumulate around the eggs. This mass is passed from the female opening to the edge of the foot, and subsequently moved to the pedal gland located in the midline of the foot about 4 of the way back from its ante- rior edge. This behavior is very similar to that of Melon- gena corona (Gmelin, 1791) described by BrincHAM & ALBERTSON (1973). The pedal gland shapes the egg capsule, and the female presses the capsule against the substratum with the foot, maintaining this position for from 5 - 12 hours. Capsules are deposited singly and are attached to various hard substrata. In surface view, the capsules are circular to oval (10 to 16mm in diameter) and, in side view, are subhemi- spherical to hemispherical, measuring 4 - 8mm in height. The opaque, white capsule operculum is fusiform to oval in shape and measures 4 - 5mm in long axis and 3 -4mm in short axis. When the capsule is viewed from the side, the operculum is situated about in the middle of the cap- sule. Capsules are whitish with a yellow central portion containing the eggs which are suspended in a viscous albuminous fluid (Figure zo). The capsule wall (Figure 11) is composed of 3 differ- entially staining layers. The innermost layer (5 - 104m thick) stains light blue with the azo-carmine technique and is composed of fine fibers. The fibers are oriented cir- cularly around the egg mass. The central layer (5 - 1oum thick) is also composed of fine fibers and stains light red with azo-carmine. The outermost layer is thicker than the other 2 layers (40 - 50m thick) and is composed of a coarse, fibrous material. This layer stains light blue with the azo-carmine procedure. Occasionally sperm were observed in the albumin surrounding the eggs and also embedded in the capsule wall. The number of eggs in a capsule varies from 200 to approximately 6800. Gener- ally, however, capsules contain between 4000 and 5500 eggs with an average of 4 700. An average of 4 cobs develop in a capsule, with a range of 0 to 8. DISCUSSION In the female genital system of neogastropods, the thin- walled portion of the gonoduet generally passes as a single, straight duct along the visceral mass and continues as a glandular portion in the mantle. The pallial portion usu- ally consists of an albumin gland, ingesting gland, capsule gland, bursa copulatrix, and vagina (Houston, 1976; FRETTER, 1941; FRETTER & GRAHAM, 1962; PONDER, 1974). The ingesting gland ingests sperm and sometimes yolk, but in some species it functions as a seminal recep- tacle (FRETTER, 1941). The capsule gland is usually the largest region and has several areas showing different staining properties in histological preparations. Typically, this gland has a ventral, non-ciliated channel which is overhung by 2 or 3 ciliated folds. Page 438 THE VELIGER Vol. 21; No. 4 In Colus stimpsoni, the female genital system conforms to the general conditions found in other neogastropods with a few exceptions. An ingesting gland is not present, and no region of the pallial oviduct appears to serve a sperm-ingesting function. A seminal receptacle is also ab- sent. The lumen of the oviduct in C. stimpsont is com- pletely ciliated, and no ventral channel is present. The walls of the albumin and capsule glands are com- posed of numerous simple tubular glands. FRETTER (1941) described the walls of these glands in Thazs lapillus as being composed of groups of cells lying at various heights, and the ducts of these groups run to the surface of the ciliated epithelium. The albumin and capsule glands in Colus stimpsoni appear very similar to those of T: lapillus according to the description and figures of FRETTER (op. cit.). However, these walls are composed of simple epi- thelial gland cells. These gland cells are clustered tightly together and drop below the surface of the ciliated epi- thelium but their apical ends reach to the level of the ciliated epithelium. These gland cells share the common epithelial basal lamina, and they secrete their products directly into the lumen, with no duct present. An ingesting gland or sperm-resorbing areas have been reported in a number of neogastropods. However, Hous- TON (1976) indicates that Colus gracilis (da Costa, 1778) also lacks an ingesting gland, as in C. stimpsont, but that a seminal receptacle is present. Special significance has been attributed to these areas (FRETTER, 1941; Houston, op. cit.). It has been suggested that the growth of ova is dependent on sperm absorption and on materials derived from sperm breakdown. It has also been suggested that the female uses the ingesting areas to remove excess sperm (FRETTER, op. cit.). It appears that fertilization occurs in the albumin gland (see also Houston, op. cit.), at the posterior end of the pallial oviduct. It is reasonable to assume that not all sperm passed to the albumin gland are utilized in fertilization, and that the moribund or dead sperm must be removed. In C. stimpsoni, the presence of sperm in the albumin surrounding the eggs and in the capsule wall suggests that excess sperm are voided with the egg mass, and females rid the oviduct of excess sperm by passing them out of the oviduct with the spawn mass. Seminal receptacles generally occur in neogastropods and are located between the albumin and capsule glands. Following copulation, sperm are transferred along the ventral channel of the pallial oviduct to the seminal re- ceptacle, where they are stored. The seminal receptacle may be divided, and one portion serves as an ingesting gland. In Colus stimpsoni no indication of an ingesting gland or seminal receptacle was observed. Also, a ventral channel is absent. In C. stimpsoni, the function of sperm storage appears to involve only the bursa copulatrix, and perhaps sperm are only transferred to the albumin gland during spawning periods. The absence of both a seminal receptacle and ingesting gland in C. stimpsoni is consist- ent with the suggestions of FRETTER (1941) and Hous- TON (1976) that these structures may have a common origin and are homologous. ACKNOWLEDGMENTS Special thanks to Drs. N. W. Riser and M. P. Morse for their advice and encouragement throughout this study. I would like to thank Drs. E. Anderson, C. H. Ellis and H. Lambert for their many helpful comments and dis- cussions during this study. Parts of this study were sub- mitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Northeastern Univer- sity, Boston, Massachusetts, and was supported in part by HEW Grant RR 07143. Literature Cited BincHam, Frasier O. & HELEN D. ALBERTSON 1973. Observations on the attachment of egg capsules to a substrate by Melongena corona. The Veliger 16 (2): 239-237; 14 text figs. (1 October 1973) FRETTER, VERA 1941. The genital ducts of some British stenoglossan prosobranchs. Journ. Mar. Biol. Assoc. U. K. 25: 173 - 211 1946. The genital ducts of Theodoxus, Laméllaria and Trivia, and a discussion qn their evolution in the prosobranchs. Journ. Mar. Biol. Assoc. U. K. 26: 312 - 351 1953. The transference of sperm from male to female prosobranch, with reference, also, to the pyramidellids. Proc. Linn. Soc. London Sess. 164: 1951-52; 2: 217-224; 3 text figs. Fretrer, Vera @ Atastam GRAHAM 1962. _ British prosobranch molluscs, their functional. anatomy ‘and eco- logy. London, Ray Soc. xvi+755 pp-; 316 figs. Houston, Roy S. 1976. The structure and function of neogastropod reproductive sys- tems: with special reference to Columbella fuscata Sowerby, 1832. The Veliger 19 (1): 27-46; 1 plt.; 10 text figs. (1 July 1976) Hyman, Liss Henrietta 1967. The Invertebrates 6, Mollusca 1: vii+792 pp.; 249 text figs. McGrawHill Book Company, San Francisco Lyons, ALANE & Tom M. SPIGHT 1973. Diversity of feeding mechanisms among embryos of Pacific North- west Thais. The Veliger 16 (2): 189-194; 3 text figs. (1 Oct. 73) Mooreg, Euna A. & Finn SANDER 1978. Spawning and early life history of Murex pomum Gmelin, 1791. The Veliger 20 (g): 251-259; 2 plts.; 2 text figs. (1 January 1978) Ponper, Winston FE 1974. The origin and evolution of the Neogastropoda. 12 (2): 295 - 338; 6 text figs. Rapwin, Gzoroz Epwarp a J. L. CHAMBERLIN 1973. Patterns of larval development in stenoglossan gastropods. Trans. San Diego Soc. Nat. Hist. 17: 107 - 118 SmitH, EpmMunp Hosart 1967. The reproductive system of the British Turridae (Gastropoda : Toxoglossa). Veliger 10 (2): 176-187; pit. 18; 16 text figs. (1 October 1967) Malacologia (11 March 1974) THorson, GUNNAR 1935. Studies on the egg-capsules and development of Arctic marine prosobranchs. Medd. on Grenland 100 (5): 1-71 1940. Notes on the egg-capsules of some North-Atlantic prosobranchs of the genus Troschelia, Chrysodomus, Volutopsis, Sipho and Trophon. Vidensk. Medd. Dansk. naturhist. Foren. 104: 251 - 265 West, Davm L. 1973- Notes on the development of Colus stimpsoni (Prosobranchia: Buccinidae). The Nautilus 87 (1): 1-4 1978. Reproductive biology of Colus stimpsoni (Prosobranchia : Buc- cinidae). I. Male genital system. The Veliger 20 (3): 266-273; 5 pits.; 2 text figs. (1 January 1978) Vol. 21; No. 4 THE VELIGER | Page 439 Egg Capsule and Young of the Gastropod Beringius beringu (Middendorff) (Neptuneidae) RICHARD A. MacINTOSH Northwest and Alaska Fisheries Center, National Marine Fisheries Service National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Washington 98112 (1 Plate) INTRODUCTION THE PROSOBRANCH GASTROPOD, Beringius beringw (Mid- dendorff, 1849) reportedly ranges from the Shumagin Is- lands, off the south side of the Alaska Peninsula, north to Point Barrow and the Amundsen Gulf in the Canadian Arctic (MacPHERSON, 1971). Recent trawl surveys con- ducted by the National Marine Fisheries Service have shown B. beringii to be common at depths between 53 and 163m on the eastern Bering Sea shelf (PEREYRA e¢ al., 1976: 345). The egg capsule and young of Beringius beringii col- lected in the eastern Bering Sea are described in this paper. Although several species of Beringius occur in the northeastern Pacific Ocean and eastern Bering Sea, only the egg capsule and young of B. eyerdami Smith have previously been described (Cowan, 1964) from this area. COLLECTION SITES anp METHODS During a bottom trawl survey in the eastern Bering Sea between June 21 and July 13, 1976, 2 live Beringtus bering and several egg cases presumed to be those of the same species were collected. The egg cases were pre- served in 10% formalin. The 2 snails, 155 and 125mm in total length, were held aboard ship in a circulating sea- water tank and, in August, placed in a saltwater aquarium and held at 5°-6°C in Kodiak, Alaska. These snails readily consumed the meat of pink shrimp, Pandalus _ borealis Kroyer, when fed at weekly or biweekly intervals. On April 22, 1977, the larger Beringius (Figure 1) laid a single capsule on the wall of the aquarium. The capsule was 39mm high, 35 mm wide, and 7.5mm thick (Figure 2). Its width decreased to 21mm near its base where it then flared out, forming a flattened 16 X 30mm sur- face for attachment to the substratum. The outer surface of the capsule wa’ pale yellow and had a smooth, un- textured, rubber-like surface. The capsule was removed from the wall of the aquarium and measured, but was not examined internally. Three rows of capsules were collected on July 11, 1976, at 57°41'N latitude, 170°16’W longitude, north of the Pribilof Islands in the eastern Bering Sea, and preserved in 10% formalin. These capsules, although similar in color, texture, and form, vary in size and relative propor- tions. Capsules ranged from 33 to 41mm high and 37 to 40mm wide. In each of the 3 rows, the capsules were laid in a straight line and one capsule generally overlapped the next (Figure 3). Two rows contained 5 capsules while the third contained 7. One row of capsules was laid on the shell of a live Beringius beringit and 2 rows were laid on dead Neptunea heros (Gray) shells. Because of the regular orientation of the capsules, it appears that a single female lays an entire row. The capsule laid in the aquarium closely resembles those taken near the Pribilof Islands with only minor differences in size and relative proportions. Among the Pribilof capsules, slight variations in these features appear to be the rule. THE EGG CAPSULE As described by Cowan (1964) for Beringius eyerdamt, each capsule was a complete envelope within an envelope (Figure 4). Each layer was about 0.15 mm in thickness. The outer surface of the capsule was smooth and rubber- like. The interior surface of the outer envelope was covered with fine ridges running parallel to the axis of the cap- sule base. Between the 2 envelopes was a layer of slender yellow fibers that lay parallel to these ridges. The fibers, about 30 - 35 mm long, were loosely attached to the walls of the envelopes, allowing the 2 walls to be easily sepa- rated. The outer surface of the inner envelope was also Page 440 covered with fine ridges along the same axis. The surface lining the brood chamber was, like the exterior of the capsule, smooth and rubber-like. Of the 17 capsules examined, 13 contained embryos. The 3 separate rows of capsules contained embryos at different stages of development; however, within a row, development was quite uniform. In the first row of cap- sules, all but one embryo had escaped. All 5 capsules were ruptured for nearly their entire width on the ventral surface about 2mm from the capsule’s edge. The single embryo that remained in this cluster was not the largest of all those examined, but was the most distinctively marked (Figure 5). The 5 capsules of the second row each contained from 13 to 15 poorly developed embryos. The foot and mantle of these 6mm embryos were well formed but no calcareous shell had developed. The 7 capsules in the third row contained embryos from Io to 16mm long that were probably close to hatching, as judged by comparison with the size and sculpturing of the previously examined embryo (Figure 5). The number of embryos per capsule ranged from 1 to 6 and was inversely proportional to the mean size of the embryos (Table 1). THE VELIGER Vol. 21; No. 4 There were significant differences in the average nym- ber of embryos per capsule in the second and third cap- sule rows. It is questionable that 15 embryos could. all grow within a capsule to a size and condition that would insure their post-embryonic survival, although SricHT (1976) stresses the variability in hatching size among nurse-egg feeding prosobranch gastropods. THORSON (1940) suggests that when large numbers of embryos inhabit a capsule, the embryos will leave the capsule and commence their free life on the sea bottom at a compar- atively early stage of development. Data presented herein suggest that the size of the embryo at any given stage of development is greater in the less crowded capsule (Table 1). Both of these relationships may hold true for Beringius beringit. THE YOUNG SNAILS The well-developed capsule young had from 1 to 13 nuclear and } to 14 post-nuclear whorls. The nucleus was generally white to pink, while the post-nuclear whorls Table 1 Number of embryos per capsule and dimensions of well developed young in a row of seven Beringius beringti egg capsules. Capsule a te Embryo Aperture Width of first number of length—mm length—mm nuclear whorl—mm nuclear whorls Number — embryos per capsule mean range mean range mean range mean range 1 zn 13.1 - 6.9 — 5.7 — 1% = 2 1 16.0 — 7.3 _ 5.7 _ 1% = 3 3 12.4 11.8-13.4 7.4 7.0-7.8 5.9 5.4-6.4 1% LA-le 4 5 11.1 10.3-11.6 7.1 6.7-7.3 5.3 4.9-5.7 1’ — 5 6 10.4 10.0-10.9 6.6 6.2-6.9 5.2 4.6-5.8 1% l'A-l 6 1 15.8 — 8.4 — 2 — 1% — 7 4 11.6 10.7-13.3 6.9 6.1-7.8 5.6 5.0-6.2 1% 1-1% Means Combined 11.7 7.0 5.5 1s 1One is crushed, no measurements obtained. Damaged, no measurement obtained. Explanation of Figures 1 to 5 Figure 1: Beringius beringu specimen that laid egg capsule on aquarium wall Figure 2: Egg capsule removed from aquarium wall Figure 3: Cluster of 5 egg capsules laid on shell of Neptunea heros Figure ¢: Diagram showing capsule wall of Beringius beringit egg capsule: a. Outer layer showing fine striations on inner surface b. Layer of slender yellow fibers c. Inner layer showing fine striations on outer surface Figure 5: Juvenile Beringius beringi taken from open egg capsule THE VELIGER, Vol. 21, No. 4 [MacIntosuH] Figures 1 to 5 Vol. 21; No. 4 ranged from pink to pinkish-brown. The color change was often quite clear cut. As in Beringius eyerdamz, the apical concretion of the first nuclear whorl was small and discrete with the sutural groove originating at nearly the center of the snail’s apex. The first few millimeters of the suture were deeply channeled. Covering the nucleus was a thin parchment-like film that adhered tightly to the lower end of the nucleus, but became loosely attached and sack-like near the apex. This sack was filled with a clear fluid in some specimens and extended in a spiral pattern for about 5mm beyond the apex. In most speci- mens, however, the sack was empty and appeared as a shriveled cap atop the nucleus. This sack was not present on the single embryo in the open egg case. The post-nuclear whorls of capsule young closely re- sembled those of adults of the species. The body whorl of the capsule young was moderately inflated and the ante- rior canal was straight, short, and broad. Spiral sculp- ture consisted of 2 to g faint, nonparallel, and irregularly spaced threads of varying length that extended from the suture to well below the periphery. The base of the body whorl was covered with up to 16 closely spaced spiral grooves, extending from a point below the peri- phery of the body whorl to the end of the anterior canal. Rounded axial ribs began to appear on the second post- nuclear whorl, and the entire whorl was covered by fine incremental growth lines. Essentially, all of the shell char- acters that distinguish adult Beringius beringit were also THE VELIGER Page 441 present in the well developed capsule young. Cowan (1964) found that the shape and sculpture of well-developed capsule young of Beringius eyerdami closely resembled that of adults of the species. This simi- larity also exists with the capsule young and adults of B. frielet Dall, 1895 from the eastern Bering Sea (personal observation). The only other Beringius in the area that could conceivably be confused with the young of B. beringu is B. stimpsoni Gould, 1860. Adult B. stimpsoni have flat sided whorls and are strongly carinate, 2 fea- tures entirely absent in B. beringti. The embryos described herein so closely resemble adult B. beringii that they can reasonably be ascribed to this species. Literature Cited Cowan, Ian McTaccart 1964. The egg capsule and young of Beringius eyerdami Smith (Nep- tuneidae). The Veliger 7 (1): 43-44; plt. 7 (1 July 1964) MacpuHerson, EvizaBetTH 1971. The marine molluscs of Arctic Canada. Natl. Mus. Nat. Sci. (Ottawa) Publ. Biol. Oceanogr. 3: 1 - 149 PEREYRA, WALTER T., Jerry E. Reeves & Ricnarp G. BAKKALA 1976. | Demersal fish and shellfish resources of the eastern Bering Sea in the baseline year 1975. U.S. Dept. Commer.,. NOAA, NMFS, Seattle, Wash. Processed Reprt. 1 - 619 Sricut, Tom M. 1976. Hatching size and the distribution of nurse eggs among proso- branch embryos. Biol. Bull. 150: 491 - 499 TuHorson, GUNNAR 1940. Notes on the egg capsules of some North-Atlantic prosobranchs of the genus Troschelia, Chrysodomus, Volutopsius, Sipho, and Trophon. Vidensk. Medd. Dan. naturhist. Foren. 104: 251 - 266 Page 442 THE VELIGER Vol. 21; No. 4 Abnormal Callus Development in Nautilus pompilius BY ROYAL H. MAPES, TERRENCE J. FREST anp STEVEN M. ARONOFF Ohio University, Athens, Ohio 45701, and The University of Iowa, Iowa City, Iowa 52242 (1 Plate) IN THE EARLY STAGES Of his study of Nautilus in the Indo- Pacific, WiLLEY (1896) reported several variations in conch morphology in N. pompilius for which he named several varieties. These varieties are based primarily on differences in the shape of the umbilical shoulder and umbilical callus — a calcium carbonate plug deposited within the umbilicus of the conch by the mantle. The taxonomic status of Willey’s varieties is uncertain. He makes no mention of them as abnormal specimens, but terms them examples of “substantive variations” (Wr1L- LEY, 1896: 229). In 1902, WiLLEy (p. 811) viewed many variations in Nautilus pompilius as aberrations. However, he did not include any shell features in this category. It is therefore uncertain whether Willey intended his varieties to have subspecific or infrasubspecific rank in the modern sense. With one exception, the specimens Willey reported as varieties had asymmetrical conchs; the exception being Nautilus pompilius variety moretoni, which was based on a single mature conch identical to N. pompilius in all respects other than its lack of umbilical calluses on both sides. MILLER (1947: 17) also reported asymmetrical callus development in N. pompilius, although it is unclear if this was a personal observation or a citation of Willey. Neither author attempted to explain the origin of the condition. Recently, an unnumbered specimen similar to Nautilus pompilius var. moretoni was found in the collections of the Museum of Comparative Zoology at Harvard Uni- versity. When this specimen is viewed from the right side, the shell appears to be that of a normal N. pomfpilius with a normal umbilical plug (Figure 1) ; when viewed from the left side, the conch appears to lack the callus (Figure 2) and looks like the specimen described by Willey as N. pompilius var. moretoni or the specimen referred to by SHIMANSKY & ZHURAVLEVA (1961) as N. moretoni Willey. Closer examination of this specimen indicates that there is an immature callus present deep within the left umbil- icus. This suggests that mantle dysfunction at some time during growth was responsible for this abnormality. Our observations indicate that the callus usually begins to develop at the nepionic constriction (conch diameter = 22 to 27mm) and the umbilical opening is completely closed by the time the animal makes a complete volution beyond the nepionic constriction (conch diameter = ap- proximately 70mm). Thus, analysis of the Harvard specimen indicates that a callus had begun to form during the post-embryonic growth of the animal, and at least one complete volution before maturity, the portion of the mantle responsible for the formation of the umbilical callus was damaged. The reason for this mantle damage is not apparent. WILLEY (1902: 732, 739) reported predatory attacks on Nautilus by sharks and conger eels, and conjectured attacks by other Nautilus (p. 810). HAVEN (1972: 79) has reported intraspecific fighting in Nautilus. The possibility of para- sitic damage of the mantle cannot be ruled out, although injury by this agency has not been reported as occurring Explanation of Figures 1 to 3 Figure 1: Normal-appearing right side of conch of Nautilus pom- pilius (maximum diameter: 123mm). approx. X 0.7 Figure 2: Left side of the specimen in Figure 1. Note the apparent lack of an umbilical callus. Figure 3: Close-up of the abnormal umbilicus of Figure 2. Note the white umbilical callus in the early, partly exposed juvenile stages. Xa Tue VELIcER, Vol. 21, No. 4 (Mares, Frest « Aronorr] Figures 1 to 3 Vol. 21; No. 4 in Nautilus. We feel that the lack of an umbilical callus is, in this instance, more likely explained as the result of non-regeneration of the mantle after injury. Due to lack of population and geographic range data, the number of biologically meaningful species of Nautilus remains problematic. The presence or absence of an um- bilical callus has been considered taxonomically signifi- cant by many workers. For example, STENZEL (1964: K88) divided the 5 generally recognized species of Nau- tilus into 2 groups on that basis. Both Willey’s specimen and that reported by Shimansky « Zhuravleva as Nautilus moretoni Willey are identical to N. pompilius except that they lack umbilical calluses. Wiiey (1897: 228) listed several characters as differ- entiating N. moretoni from N. pompilius (s. str.), but it is clear from both his description and figures that all could result simply from failure by an individual to develop umbilical calluses. In order to clarify the position of Nautilus moretont, it is necessary to examine the nomenclatural and taxo- nomic status of this “species.” SHIMANSKY & ZHURAVLEVA (1961) appear to have elevated Willey’s Nautilus pom- pilius variety moretoni to species status as N. moretoni Willey. Because their action was taken after some relevant sections of the International Code of Zoological Nomen- clature took effect, it is only questionably valid. Under the present rules, varieties named after 1960 are, by defi- nition, of infrasubspecific rank [article 45¢(ii) ] and hence cannot be elevated in rank according to the provisions of article 1 (Stott et al., 1963: 5, 47). A variety published prior to 1961 can be regarded as of subspecific rank if the original author “did not clearly state its rank” (article 45d(i): Stow et al., 1963: 45). This provision is prob- ably applicable in this case, but its force is qualified by article 45e(i) (Stout et al., op. cit.) : “Before 1961, the use of either the terms ‘variety’ or ‘form’ is not to be interpreted as an express statement of either subspecific or infraspecific rank.” According to Mayr (1969: 362) it is good taxonomic practice to “give the benefit of the doubt” to authors who introduced varieties prior to 1961. Possibly this is what SHIMANSKY & ZHURAVLEVA (1961) had in mind; but as no explanation was provided, this must remain con- jectural. As we have stated above, from a morphologic standpoint, Nautilus moretoni is also suspect. Nautilus pompilius can lack one umbilical callus, and there is no THE VELIGER Page 443 reason why both calluses could not also be missing. Thus, both Willey’s specimen and that illustrated by Shimansky & Zhuravleva as N. moretoni Willey may be abnormal N. pompilius that failed to develop umbilical calluses, at least in later stages of growth. In our opinion, N. moretont Willey is best regarded as being based on teratologic speci- mens and the name should be treated as a synonym of N. pompilius Linnaeus, 1758. As neither Willey’s nor Shi- mansky & Zhuravieva’s specimens were available to us for study, it remains to be investigated whether or not juvenile calluses are present on their specimens. Even if they are not present, recognition of a separate species solely on the basis of presence or absence of the umbilical calluses is probably not justified. ACKNOWLEDGMENTS Helpful editorial criticism and advice about Nautilus were provided by Brian F. Glenister. Gilbert Klapper con- tributed valuable suggestions concerning interpretations of the International Code of Zoological Nomenclature. Kathleen Lewis assisted in the translation of Shimansky « Zhuravleva’s work. To all, our thanks. Literature Cited Haven, Norinz 1972. The ecclogy and behavior of Nautilus pompilius in the Philig- pines. The Veliger 15 (2): 75-80; 2 plts.; 2 text figs. (1 Oct. ’72) 1969. Principles of systematic Zoology. xi+428 pp.; illust. Muiuer, A. K. 1947. ‘Tertiary nautiloids of the Americas. Mem. 28: 234 pp. Suimansky, V. N. a FE A. ZHURAVLEVA 1961. Scientific studies of nautiloids and related groups. Akad. Nauk SSSR, Paleont. Inst., Trudy 90: 175 pp. Stenze., Henryk BronisLaw 1964. Living Nautilus. pp. K59-K93 in: Treatise on Invert Paleont., R. C. Moore, ed., prt K, Mollusca 3. Univ. Kansas Press, Lawrence, Kansas Stott, Norman Rupovpa et al. 1964. International code of zoological nomenclature adopted by the XV International Congress of Zoology, London. Internat. Trust f. Zool. Nomencl. London; xx+176 pp.; 5 appendices; glossary Wituzy, ARTHUR 1896. Zoological observations in the South Pacific. Quart. Journ. microsc. Sci. N. S. 39: 219- 231 1902. Contributions to the natural history of the pearly Nautilus: Zoological results based on material from New Britam, New Guinea, Loyalty Islands, and elsewhere, etc. prt. 6: 691 - 830 Cambridge Univ. Press McGraw - Hill, New York. Geol. Soc. Amer. Page 444 THE VELIGER Vol. 21; No. 4 The Genus Callistochtton Dall, 1879 (Mollusca : Polyplacophora ) in the Eastern Pacific, with the Description of a New Species BY ANTONIO J. FERREIRA! Research Associate, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118 (3 Plates; 9 Text figures) THE GENUS Callistochiton Dall, 1879, is particularly well represented in the eastern Pacific. Ten species are recog- nized here, 4 in the north temperate region (one new to science), 5 in the tropical region, and 1 in the south tem- perate region, distributed between 40°N and 20°S. The genus has representatives worldwide, mostly in the tropi- cal belt, but nowhére with the abundance with which it is found on the west coast of the American continent. The purpose of this paper is to review the taxonomic position of the eastern Pacific chiton species assigned to the genus Callistochiton and ascertain their currently known ranges of distribution. The work is-based upon the chiton collections in the California Academy of Sciences (CAS), Natural History Museum of Los Angeles County (LACM), Allan Hancock Foundation (AHF), National Museum of Natural History (USNM), Academy of Natural Sciences of Philadelphia (ANSP), University of California at Los Angeles (UCLA), San Diego Museum of Natural History (SDNH), American Museum of Nat- ural History (AMNH), British Museum (Natural His- tory) (BMNH), and the private collections of Glenn & Laura Burhardt, Salle Crittenden, George A. Hanselman, Allyn G. Smith (AGS), and Antonio J. Ferreira (AJF). POLYPLACOPHORA de Blainville, 1816 Neoloricata Bergenhayn, 1955 ISCHNOCHITONINA Bergenhayn, 1930 1 Mailmg address for reprints: 2060 Clarmar Way, San Jose, CA (lifornia) 95128, U.S. A. CALLISTOPLACDAE Pilsbry, 1893 Callistochiton Dall, 1879 Tegmentum conspicuously sculptured; end valves and Iat- eral areas of intermediate valves with strong radial ribs which, on closer examination, often appear as undula- tions rather than thickenings of the tegmentum; these “ribs” are often granose or tuberculated. Characteris- tically, the lateral areas are bicostate, and the end valves have no more than 10-12 ribs. The central areas of the intermediate valves are usually strongly sculptured, too, with longitudinal riblets, latticing, or a pitted appear- ance. The insertion plates tend to be relatively short; the insertion teeth are often thickened at the edges of the slits and festooned at the free edges. The slits tend to cor- respond in number and position to the ribs of the teg- mentum. The intermediate valves are uni-slitted. The sutural laminae are relatively short, subquadrate to semi- oval; sinus relatively shallow. Girdle narrow, densely set with relatively small, imbricating scales. Gills as long as the foot. Type species: Callistochiton palmulatus Dall, 1879, by M Remarks: Many workers consider “Carpenter in Dall” as the proper authority for Callistochiton. Unquestiona- bly, Callistochiton was Carpeénter’s manuscript name_and arrangements as revealed not only by Dati (1879), Tryon (1883), and Prtssry (1893), but through the ex- amination of the relevant pages in Carpenter’s unpub- lished manuscript in the repository of the National Muse- um of Natural History, Washington, D. C., made available to me through the kindness of Dr. Joseph Rosewater. But Vol. 21; No. 4 since names proposed in unpublished manuscripts have no taxonomic standing, the fact remains that it was DALL (1879), who adopted and first published the name Call- istochiton, defining the genus with the description and figure of the radula of C. palmulatus. Thus, there seems to be no justification for the dual authorship “Carpenter in Dall,” often given to Callistochiton. It must be added that the case of Callistochiton differs from those where the second author gives the first author’s description, or illustration, or both; for instance, in several species with the authorship “Carpenter in Pilsbry,” such as Lepidozona sinudentata, the dual authorship is appropriate inasmuch as Pilsbry quotes directly from Carpenter’s unpublished manuscript in a manner which makes it clear where Car- penter’s contribution ends and Pilsbry’s begins. THIELE (1929: 18) placed Callistochiton as a sub- genus in Lorica H. & A. Adams, 1852 (together with Lorica s. s. Lepidozona Pilsbry 1892, Loricella Pilsbry, 1892, and Squamophora NierstraB, 1905), apparently on the basis of radular characteristics. This taxonomic ar- rangement has had no acceptance among chiton workers (FERREIRA, 1974). Synonyms: Lophochiton Ashby, 1923 [not Berry, 1925], (Type: Lophochiton johnstoni Ashby, 1923, by OD): Callistassecla Iredale & Hull, 1925 (Type: Callistochiton mawlei Iredale & May, 1916, by OD) ; Callistelasma Ire- dale « Hull, 1925 (Type: Chiton antiquus Reeve, 1847, by OD). Callistochiton palmulatus Dall, 1879 (Figure 7) “Callistochiton palmulatus Cpr.” Dat, 1879: 297; fig. 20 (radula) Callistochiton palmulatus. Happon, 1886: 20 — THIELE, 1893: 378; plt. 31, fig. 8 (radula) — Pirssry, 1893, 14: 262 to 264; plt.58, figs. 7-16 — Berry, 1907: 52 — E. P Cracz, 1917: 30 (Pleistocene) — Dati, 1921: 193 — JOHNSON & SNOOK, 1927: 564-565; fig. 663 - Otproyp, 1927: 894 — T. A. Burcu, 1942: 7 — J. Q. Burcu « T. A. BurcH, 1943: 5, 7 — PALMER, 1945: 101 — A. G. SmiTa, 1947: 18 — A. G. SmrrH & Gorpon, 1948: 208 — LE- LOUP, 1953: 17 - 18; fig. 11 (with syn. Callistochiton pal- mulatus mirabilis Pilsbry, 1893) — LicuT’s Manual, 24 ed., 1954: 217-218 — PaLMeER, 1958: 279; plt. 32, fig. 1 — G. « L. BureHarprt, 1969: 12; pit. 1; figs. 7, 8 (with syn. Callistochiton acinaius Dall, 1919, and C. celetus Dall, 1919) — McLean, 1960: 63 - 64; fig. 35.4 — A. G. SurrH in Light’s Manual, 3™ ed., 1974: 463, 464 — AB- BOTT, 1974: 399 — A. G. SmiTH, 1977: 217, 239-240 THE VELIGER Page 445 (with syn. Callistochiton acinatus Dall, 1919, C. celetus Dall, 1919, and C. connellyi Willett, 1937) Callistochiton palmulatus mirabilis Prrspry, 1893, 14: 263 to 264; pit. 58, figs. 7-11; 1898: 288 — Berry, 1907: 52 —Cuace, 1917: 30 (Pleistocene) — Darr, 1921: 194 — BERRY, 1922: 409-412, 415, 489-492; tbl. 1; text fig. 11; plt. 14, figs. 9- 16; plt. 15, figs. 1- 14 (Pleistocene) ; 1926: 456 (Pleistocene) — OLproyp, 1927: 894- 895 — J. Q. « T.A. Burcn, 1943: 5 — A. G. Smrrx, 1947: 18 —. A. G. SmrrH « Gorpon, 1948: 208 —- LELoup, 1953: 17 - 18; fig. 11 (syn. of C. palmulatus) — Licut’s Manu- al, 2"4 ed., 1954: 218 — A. G. Smitu, 1963: 148 —- G. L. BurcHARDT, 1969: 12 — A. G. Smrru in Light’s Man- ual, 3 ed., 1974: 464 Callistochiton acinatus DALL, 1919: 510; 1921: 194 — OLpD- ROYD, 1927: 898 — A. G. Smrrn, 1947: 18 -G.é« L. BuRGHARDT, 1969: 12 (syn. of C. palmulatus) — ApBortt, 1974: 399 — A. G. SmrrH, 1977: 217, 239 (syn. of C. palmulatus) Callistochiton celetus DALL, 1919: 510-511; I921: 194 — Oxproyp, 1927: 898 — A. G. SmitH, 1947: 18 - G. & L. BurRGHARDT, 1969: 12 (syn. of C. palmulatus) — As- BOTT, 1974: 399 — A. G. SmITH, 1977: 217, 239 (syn. of C. palmulatus) Callistochiton connellyt WILLETT, 1937: 25 - 26; plt. 2 fig. 13 — A. G. Smrru, 1947: 18 — A. G. SmirH « Gorpon, 1948: 208 — G. & L. BurcHarnt, 1969: 11; plt. 1, fig. 4 — AppoTt, 1974: 399 — A. G. SmiTH, 1977: 217, 240 (syn. of C. palmulatus) Description: Chitons with high-arched, rounded back. Length up to 1:5cm. Color light creamy, often with greenish to gray specks. Anterior valve with g - 11 mas- sive, somewhat pustulose, radial ribs. Posterior valve of ten raised and thickened by the presence of 4 to 6 un- usually strong radial ribs; mucro anterior. Lateral areas of intermediate valves robustly bicostate. Central areas with some 15 longitudinal riblets per side, finely cross- ribbed. In the end valves, the sulci between the radial ribs are wide and coarsely pitted; similarly, pitted sulci separate the radial ribs in the lateral areas. Girdle often banded and covered with closely set, imbricating, oval scales about 150 um in length, with some 10-12 deep striations (Figure z). Articulamentum white. Valves thick and massive. Sutural laminae semioval, sharp; sinus hardly formed, almost absent in the posterior valves. In- sertion teeth short; in valve i there are 9-11 teeth, somewhat thickened at the edge of the slits, corresponding in position to the radial ribs of tegmentum; intermediate valves unislitted ; posterior valve conspicuously thick, with a close series of small, irregularly shaped teeth, about 20 in number. The radula is figured in Dati (1879: fig. 20), and THIELE (1893: plt. 31, fig. 8). Dall’s description of the Page 446 major lateral as having “a simple cusp” (DALL, op. cit.: 297) is not correct; as Thiele’s illustration shows, there are 2 cusps, a large inner cusp, and a small outer one. The examination of the radulae of 6 specimens of Call- istochiton palmulatus from several localities corroborated the anatomical details shown in Thiele’s figure; Dall’s figure is compatible with Thiele’s and my own observa- tions except for the description of the cusp of the major lateral. However, the difficulties of correctly observing the radula, particularly if the specimen happens to be small, may easily explain the discrepancy; in addition, if viewed from the side the cusp may look single and simple, as Dall illustrated and described. A specimen of C. palmulatus (Monterey Bay, California, leg. A. J. Ferreira, at 20m, June 30, 1977, AJF 342), measuring 16.2mm in length, has a radula 6.3mm long, 2. e., 39% of the specimen’s length with 40 rows of mature teeth. The median tooth is 135m long, enlarged anteriorly where it bears a thin blade about 95 um wide. First lateral has the characteristic knob in the outer-anterior corner. The major lateral is bicuspid, the larger inner cusp meas- uring 125m in length. Outer marginal teeth are elon- gated, measure 115 um in length, 75 wm in width. Type Material: Dall limited himself to a description of the radula; his material could not be located either at the National Museum of Natural History, or at the Academy of Natural Sciences of Philadelphia, and is presumed lost. The first complete description of the species comes from Pirssry (1893: 14: 262-263) based on Carpenter's manuscript description, drawings and specimens. The description corresponds to a specimen in the Carpenter Collection in the Redpath Museum, Canada, bearing the label “type, Sta. Barbara, Cooper no. 1077” (fide Pat- MER, 1958: 279). The specimen is regarded as a holotype by PALMER (loc. cit.). Since the author of Callistochiton palmulatus is Dall, not Carpenter, Palmer’s designation under the present rules of the ICZN is incorrect; the radu- la, or, rather the specimen from which the radula was obtained, that served Dall as the basis for his “descrip- tion,” would be the holotype. In the interest of the stabili- ty of nomenclature and fixation of the concept of the species C. palmulatus, the specimen illustrated by PALMER (op. cit.: plt. 32, fig. 1), and described in Pmssry (op. cit.: 262 - 263) is herein designated as a neotype. The specimen, as stated by PALMER (op. cit.: 279) measures 8mm in length and 7mm in width; it is preserved dry, with valves i, vii, and vii separated, as Redpath Museum no. 48. Callistochiton palmulatus mirabilis Pilsbry, 1893: syn- types (ANSP 118682): type locality, San Diego, Cali- fornia. THE VELIGER Vol. 21; No. 4 Callistochiton acinatus Dall, 1919: holotype (USNM 218733) ; type locality, San Pedro, California. Callistochiton celetus Dall, 1919: lectotype and. para- lectotype (USNM 218770); type locality, San Pedro, California. Callistochiton connellyi Willett, 1937: holotype (LAC M 1048), and several paratypes; type locality, “Arbolitos Point, near Ensenada, Lower California, Mexico.” Type Locality: The locality of Dall’s original specimen is unknown. The locality of the neotype specimen, as given by Pirssry (1893) and PALMER (1958) is Santa Barbara [34°25’N, 119°42’W], Santa Barbara County, Califor- nia. Distribution: Seemingly continuous between parallels 39° N and 27°N. The northernmost record is Buckhorn Creek [39°17’ N, 123°48’ W], Mendocino County, Cali- fornia (CASG 32233). The southernmost record is San Pablo Point [27°12’N, 114°29’W], Baja California, Mexico (LACM 71-178). The species has been collected at most offshore islands, namely Santa Rosa (LACM-AHF 1282-41), Santa Cruz (LACM 96-32), Anacapa (LACM AHF 1421-41), Catalina (LACM 64-26), San Nicolas (LACM-AHF 1694-49), San Clemente (LACM-AHF 66-51), Coronados (LACM 63-41), Natividad (LACM 72-116), San Gerédnimo (LACM 71-91), San Martin (LACM-AHF 1694-49), Guadalupe (CASG 32746), and Cedros (LACM 72-115). Known bathymetric range ex- tends from the intertidal zone to 40 - 50 fathoms [73 - 82 m] (LACM-AHF 1297-41). Fossil Record: Pleistocene deposits in southern Califor- nia (CHACE, 1917; BERRY, 1922), in San Quintin, Lower California, Mexico (Berry, 1926) and in Guadalupe Island (FERREIRA, 1978a). Remarks: The subspecies Callistochiton palmulatus mi- rabilis Pilsbry, 1893, is suppressed here as a synonym, as already suggested by LELoup (1953: 17 - 18). The obser- vation of many intergradations between the 2 morphs “palmulatus” s.s. and “mirabilis,” and their total lack of correlation to locality or depth demonstrate that the forms of tail valve and mucro represent intraspecific variation with no taxonomic significance. Callistochiton acinatus Dall, 1919 and C. celetus Dall, 1919 were found to be synonyms of C. palmulatus upon examination of the re- spective type material (A. G. SmirH, 1977: 239). The synonymy of C. connellyi Willett, 1937, already indicated by A. G. SmirH (op. cit.: 240), was reaffirmed upon examination of the holotype through the courtesy of Dr. James H. McLean. Vol. 21; No. 4 THE VELIGER Page 447 Callistochiton crassicostatus Pilsbry, 1893 (Figures 2, 3) Callistochiton crassicostatus Prrspry, 1893, 14: 264 - 265; pit. 58, figs. 1-6; 1898: 288 — Berry, 1907: 52 — E. P CwHacz, 1917: 30 (Pleistocene) — E. PR & E. M. Cuacz, 1919:2 (Pleistocene) — DaLt,1921: 194 — BERRy, 1922: 409 - 410, 412, 414, 484 - 488; tbl. 1; text fig. 10; plt. 13, figs. 1 - 16 (Pleistocene) - OLpRoyp, 1924: 194 — BERRY, 1926: 456 (Pleistocene) — JoHNSON & SNOOK, 1927: 565; fig. 665 —- O_pRoyp, 1927: 895 — STRONG, 1937: 194 — T. A. Burcu, 1942: 7 — A. G. SmrTH, 1947: 18 — A.G.SmitH & Gorpon, 1948: 208 — LaRocgug, 1953: 12 — LeLoup, 1953: 5-6; fig. 8 — LicHt’s Manual, 2™4 ed., 1954: 217-218 — G. & L. BurcHarnr, 1969: 11 - 12; pit. 1, fig. 5 - McLean, 1969: 63; fig. 35.2 — ABBOTT, 1974: 399 — A. G. SmitH in Light’s Manual, 3™ ed., 1974: 463 - 464 “Callochiton fimbriatus Cpr.” Cooper, 1867: 23 [nomen nu- dum] [not Chiton fimbriatus Sowerby, 1840] “Chiton (Callochiton) fimbriatus Cpr.” Orcutt, 1885: 544 [nomen nudum]; 1915: 23 [nomen nudum] ““Callistochiton fimbriatus’ Carpenter, MS, nomen nudum” PALMER, 1958: 278 Description: Chiton with high arched, round back. Length up to 3cm. Color creamy tan to gray or light green. Anterior valve with 7 strong, somewhat granose radial ribs, each often divided by 1 - 4 sulci which be- come more apparent towards the periphery. Posterior valve with 5 equally strong radial ribs, again often sub- dividing at the periphery; mucro well defined at the posterior edge of the valve with markedly sloped, almost vertical, and convex postmucro. Lateral areas of inter- mediate valves with a single, very strong radial rib, usually subdivided by 4-6 sulci; the radial ribs often show concentric annulations, about 12 per rib, which together with the radial sulci tend to divide the single rib into coarse granules. Central areas have longitudinal rib- lets, about 12 per side, which remain parallel to the jugum or may converge slightly anteriorly; the riblets are finely cross-ribbed. Girdle narrow, often banded and covered with close set, imbricating oval scales, about 100 - 120 um in length, with some 6-8 deep striations (Figure 2). Articulamentum is white or bluish-white. Sutural laminae thin, semioval, separated by a relatively small, rounded sinus. Anterior valve with 8 - 9 very short teeth, thickened at the edges, festooned at the free edge; intermediate valves uni-slitted; posterior valve very thick and massive, with a series of 12-20 very short teeth, usually blunt and irregular in shape and size. The radula of a specimen of Callistochiton crassicosta- tus 23.0mm long (Monterey Bay, California, leg. A. J. Ferreira, September 1973, at 13m, AJF 89) measures 8.0mm in length, 7. e., 35% of the specimen’s length. It has 48 rows of mature teeth, morphologically very similar to those of Callistochiton palmulatus. The median tooth is enlarged in front (where it bears a blade, 125 um in width) and narrows posteriorly to about 50 um; in length it measures about 200 um. The first laterals are subquad- rate, with a knobby protuberance in the outer-anterior corner. The major (2™°) lateral has a bicuspid head, the inner cusp somewhat larger than the outer cusp (Figure 3); the head measures about 100 ym in width, and 100 um in the length of the longest (inner) cusp. Outer mar- ginal teeth are elongated, 140 um long and 100 um wide. 100 pm —— Figure 3 Callistochiton crassicostatus Pilsbry, 1893 Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected at Monterey Bay, California (AJF 89), original length 23.0mm Type Material: Syntype series (ANSP 118683), com- posed of 3 specimens, 1 wholly disarticulated but with girdle (Dr. Robert Robertson, in litt., 24 August 1976). The disarticulated specimen, very likely the one illustrated by Pmissry (1893, 14: pit. 58, figs. 4-6), is here desig- nated as lectotype. Type Locality: “Monterey [36°37’N, 121°55’W], Cali- fornia” as stated by Pitssry (1893, 14: 265). Page 448 Distribution: Apparently continuous between parallels 36°N and 31°N. The northernmost record from the a- vailable collections is Trinidad [41°04’N, 124°10’W], Humboldt County, California (Glenn & Laura Burg- hardt Collection, in lizi., g August 1975); reported records from farther north, such as Puget Sound, Washington (OLDRoyD, 1924: 194), and Forrester Island, Alaska (DALL, 1921: 194) have not been confirmed. Callisto- chiton crassicostatus is particularly abundant from Monte- rey Bay to San Diego, California. The verified southern- most record is Cedros Island [28°10'N, 115°15/W], Baja California, Mexico (SDNH 23474, leg. H. N. Lowe). On the offshore islands it has been collected at Santa Cruz (LACM-AHF 1660-48), San Miguel (CASG 13778), Catalina (LACM-AHF 1903-49), and Coronados (LA CM 63-41). Bathymetrically, it has been recorded from the intertidal zone to 27 - 31m (LACM-AHF 1903-49). An unusual finding was the collection of a single speci- men, estimated length 2.5cm, at “400-350 fathoms [732 to 640m] on mud, 11 miles [17.6km] northeast of Ava- lon, Santa Catalina Island, Los Angeles County, Califor- nia (33°2724”N, 118°10'53”W), August 11, 1951,” (LA CM-AHF 2049-51). It is also of interest to note that in the available collections I found no instance of the species having been collected between Punta Banda (31°43'N, 116°43’W), Baja California, Mexico (LACM 63-42), and the Cedros Island site, some 3° south, mentioned above. Fossil Record: Pleistocene deposits in San Quintin, Lower California, Mexico (Berry, 1926) ; Santa Monica Hills (Cuace, 1917), and San Pedro (CHacE & CHAcE, 1919; Berry, 1922) in southern California. Remarks: The taxonomic position of “Callistochiton fimbriatus,” a Carpenter manuscript name, has been suf ficiently clarified in Prispry (1893, 14: 265 - 266) and PALMER (1958: 278-279) so as to require no further comment. Callistochiton decoratus Pilsbry, 1893 “Chiton (Callistochiton) decoratus Cpr.” Orcutt, 1885: 544 [nomen nudum] THE VELIGER Vol. 21; No. 4 “Callistochiton decoratus Carpenter, n. sp.” Prrspry, 1893, 14: 269 - 270; plt. 58, figs. 17 - 20 Callistochiton decoratus. E.P.CHacr,1917: 44 -E.P & E.M. Cwacez, 1919: 2 (Pleistocene) - Dati, 1921: 194 — Oxp- ROYD, 1927: 896 —- T. A. BurcH, 1942:7 — PALMER, 1945: tor — A. G. Smrrn, 1947: 18 — LELoup, 1953: 6-7; fig. 4 — Parmer, 1958: 278; plt. 33, figs. 15-21 - G. & L. BurcHarnt, 1969: 12; plt. 1, fig. 6 (with syn.: C. chthonius and C. cyanosus) — McLean, 1969: 63; fig. 35.3 — ABBOTT, 1974: 39 (with syn. C. punctocostatus, C. ferminicus, C. chthonius, and C. cyanosus) — A. G. SMITH, 1977: 217, 240 (with syn. C. cyanosus, C. decor- atus punctocostatus, and C. chthonius) Callistochiton decoratus punctocostatus Prspry, 1896: 50 — Dati, 1921: 194 — Berry, 1922: 409, 418, 481- 483; tbl. 1; pit. 14, figs. 1-6 (Pleistocene) - OtproyD, 1927: 897 — A. G. Samira, 1947: 18 — A. G. SurrH & Gorpon, 1948: 208 — G. « L. BurcHarpt, 1969: 12 — ABBOTT, 1974: 399 (syn. of C. decoratus) — A. G. SmrrH, 1977: 217, 240 (syn. of C. decoratus) Callistochiton decoratus ferminicus BERRY, 1922: 483; plt. 14, figs. 7-8 (Pleistocene) - ABBoTT, 1974: 399 (syn. of C. decoratus) Callistochiton diegoensis THre.E, 1910: 86 - 87; plt. 9, figs. 4-10 — Dauz, 1921: 194 — OLpRoYD, 1927: 897 — A. G. SmrrH, 1947: 18 — ABBOTT, 1974: 399 Callistochiton cyanosus DALL, 1919: 511; 1921: 194 — OnD- ROYD, 1927: 900 — A. G. SmrrH, 1947: 18 — G. « L. BurRGHARDT, 1969: 12 (syn. of C. decoratus) — Axsorr, 1974: 399 (syn. of C. decoratus) — A. G. Smaru, 1977: 217, 240 (syn. of C. decoratus) Callistochiton chthonius Daut, 1919: 511-512; 1921: 194 Oxproyp, 1927: goo — A. G. SmirH, 1947: 18 - G. a L. BurGHARDT, 1969: 12 (syn. of C. decoratus) — Ansott, 1974: 399 (syn. of C. decoratus — A. G. Smrrm, 1977: 217, 240 (syn. of C: decoratus) Description: Chitons with relatively low-arched, round backs. Length up to 3cm. Color usually uniform olive- green to tan, often with darker flecks. Anterior valve with 10 - 12 rounded radial ribs, of a relatively smooth surface except for some occasional growth rings; radial ribs sep- arated by very well defined and pitted sulci. Posterior valve with 8 - 10 similar radial ribs; mucro well defined, slightly posterior. Lateral areas of intermediate valves bicostate, again with the 2 rounded ribs separated by a pitted sulcus. Central areas with 8 - 12 longitudinal rib- Explanation of Figures 7, 2, 4, 5, 16, 17 Figure 1: Callistochiton palmulatus Dall, 1879. Girdle scales. SEM micrograph by Dennis Nichols and Myrl Stone X 700 Figure 2: Callistochiton crassicostatus Pilsbry, 1893. Girdle scales. SEM micrograph by Dennis Nichols and Myrl Stone X 300 Figure 4: Callistochiton asthenes (Berry, 1919). Girdle scales. SEM micrograph by Hans Bertsch X 300 Figure 5: Callistochiton asthenes. Girdle scales. SEM micrograph by Hans Bertsch X 1000 Figure 16: Callistochiton colimensis (A. G. Smith, 1961). Cuasto- comate, Jalisco, Mexico (LACM 68-41). Length 17mm Figure 17: Callistochiton colimensis. Girdle scales. SEM micro- graph by Hans Bertsch X 620 THE VELIGER, Vol. 21, No. 4 [FERREIRA] Figures 1, 2, 4, 5, 16, 17 Vol. 21; No. 4 lets per side, parallel (or slightly divergent anteriorly), neatly cross-ribbed for a latticed effect. Jugum usually smooth (i. e., not ribbed, the ribs having become obsolete), often lustrous and shiny, as if polished, a tegmental char- acteristic sometimes also noticed on thesurface of the radial ribs of the end valves and lateral areas. Girdle, often banded, tan or dark green. Girdle scales strongly imbri- cated, oval, measuring about 160 - 200 um in length, and showing 8 - ro deep striations. Articulamentum white to bluish, often with a dark brown discoloration at the apex of the valve, particularly on valve viii. Sutural laminae relatively wide and semioval; sinus well defined, the sinusal lamina with a few irregular pectinations, usually separated by a small notch from the adjacent sutural laminae. Anterior valve with 9-11 teeth, thickened at the edges, festooned at the free edges; intermediate valves uni-slitted; posterior valve with 9-11 similar teeth. In some specimens the insertion plate of the posterior valve may be divided into very small teeth (over 25 in one small specimen examined), often short, irregular in shape and size, and not continued by a slit ray. The radula is very similar to those of Callistochiton pal- mulatus and C. crassicostatus. A specimen 21mm in length (San Clemente Island, California, leg. A. J. Fer- reira, 26 October 1975, at rom, AJF 252) has a radula measuring 6.7mm in length, 7. e., 32% relative size, with 70 rows of mature teeth. Median tooth large in front (100 pm) where it has a small blade, tapers posteriorly; length of the tooth about 125 um. First lateral teeth have a knobby protuberance in the outer-anterior corner. Sec- ond Iateral has a bicuspid head about 50 um in width; the inner cusp, the longest of the 2, is about 100 um in length. The outer marginal teeth are elongated, measuring 100 pm in length, 80 um in width. Type Material: Holotype (ANSP 118687). “Although Pilsbry utilized Carpenter’s manuscript name for this species, he did not use Carpenter’s description or his type. Pilsbry’s type was a specimen in the Academy of Natural History, Philadelphia.” (PALMER, 1958: 278). Callistochiton diegoensis Thiele, 1910: Holotype (Zoo- logisches Museum, Berlin). Color slides at CASIZ nos. 3339-3340 Callistochiton decoratus punctocostatus Pilsbry, 1896: Syntypes (ANSP 118689) Callistochiton chthonius Dall, 1919: Holotype (USNM 109488) Callistochiton cyanosus Dall, 1919: Holotype (USNM 109317) Type Locality: ‘Todos Santos Bay and near San Tomas River [31°48’N, 116°42’W], Lower California” (Prs- BRY, 1893, 14: 269). THE VELIGER Page 449 Distribution: Continuous between parallels 34° N and 31°N. Northernmost record, Point Arguello [34°25/N, 120°39’W], Santa Barbara County, California (CASIZ 006298) ; southernmost record, Isla Cedros [28°10'N, 115°15 W], Baja California, Mexico (SDNH 23226). Callistochiton decoratus has also been collected at the offshore islands of Santa Cruz (AJF, December 1970), Santa Rosa (LACM 73-9), Anacapa (LACM M-41), Santa Barbara (LACM 72-97), Catalina (LACM-AHF 1652-48), San Clemente (LACM-AHF 1021-39), and Coronados (LACM A-5757). It is interesting to note that, just as with C. crassicostatus, there has been no recorded collection of C. decoratus between Punta China (31°33'N, 116°40’W), Baja California, Mexico (LACM -AHF 1596-47), and Cedros Island, some 3° south. The presence of C. decoratus in the Gulf of California, “. . . re- ported ... from La Paz by Carpenter (Pease coll.)” (Prissry, 1893, 14: 270), has never been confirmed. The known bathymetrical range of C. decoratus extends from the low intertidal zone to about 72m (LACM-AHF 1191-40-D1, Santa Cruz Island). Fossil Record: Pleistocene deposits in San Pedro, south- ern California (CHACE & CHACE, 1919; BERRY, 1922). Remarks: The subspecies Callistochiton decoratus punc- tocostatus Pilsbry, 1896, is here placed in synonymy inas- much as the alleged sculptural differences fall well within the range of intraspecific variation accorded to C. deco- ratus, as already noted by LELoup (1953: 6-7), and A. G. SmirH (1977: 240). The synonymization of C. cyan- osus Dall, 1919 and C. chthonius Dall, 1919, follows from Dall’s original description, and the study of the holotypes, as reported by A. G. SmirH (op. cit.: 239 - 240). The type material of Callistochiton diegoensis Thiele, 1910, consists of a single specimen preserved in alcohol in the repository of the Zoologisches Museum, Berlin, Deutsche Demokratische Republik. The specimen was made available for study through the generosity of Dr. R. Kilias; it measures 17.0mm in length and corresponds in every detail to the description and illustration provided by THIELE (1910); valves i, v, and viii, disarticulated and ségregated in a vial, are those figured by THIELE (op. cit., plt. 9, figs. 4- 10). The specimen is unquestionably conspecific with C. decoratus; although the tegmental features are a bit sharper than usual, the deviation is well within the known intraspecific variation of the species. Callistochiton decoratus ferminicus Berry, 1922, was placed in the synonymy of C. decoratus by LeLouP (1953); indeed, the stated distinctions would hardly justify a new name, particularly in view of the fact that, as Berry himself acknowledged, C. decoratus “is so extraordinarily variable a chiton” (BERRY, 1922: 483). Page 450 Callistochiton asthenes (Berry, 1919) (Figures 4, 5, 6) Ischnochiton (Lepidozona) asthenes BERRY, 1919a: 7; 1919b: 18-21; plt. 8, figs. 1-2 Ischnochiton asthenes. DALL, 1921: 192 (in section Lepido- zona) Lepidozona asthenes. A. G. SmitH, 1963: 148-149; 1966: 438-442 - G. & L. BurcHarpt, 1969: 20 — AssorT, 1974: 395 Callistochiton asthenes. FERREIRA, 1978b: 39 Description: Chitons moderately elevated and slightly carinated. Length up to 1cm. Tegmental surface micro- granulose. Color cream to light brown. Anterior valve with 11 - 12 very low, broad, radial ribs, often very indistinct except at the periphery of the valve; in some specimens a radial series of 2 - 4 minute pustules (apparently easily abraded) may be observed cresting the radial ribs. Poste- rior valve with mucro anterior; post-mucro area with radial ribs similar to those in anterior valve, only usually much weaker and less distinct, obsolete in some specimens. Intermediate valves with lateral areas clearly raised in most specimens, bicostate, the ribs broad and flattened, bearing a series of 2-4 minute pustules. These pustules (or tubercles) are absent in most specimens examined, either because they are easily abraded (as Berry, 1919, suggested), or perhaps because they had not (yet?) de- veloped. Central areas with some 15 finely sculptured longitudinal riblets, subtly interlatticed; these riblets are not present in young specimens, and in older (larger) ones become obsolete towards the jugum which appears devoid of sculpturing except for the rather “scaly” micro- granulose appearance of the tegmental surface. Articula- mentum white. Sutural laminae thin and broadly arcuate; sinus small. Insertion teeth sharp, very slightly festooned and somewhat thicker at the edges. Slit formula of a specimen from the type locality: 9 - 1 - 9. Girdle covered with imbricated, oval, rather small scales (about 150 um in length), with about 10 ribs separated by neatly pitted striations (Figures 4, 5). The radula is figured here for the first time (Figure 6). In a specimen 7.6mm long (CASG 38607, White’s Point, Los Angeles County, California, leg. W. J. Raymond, 1901), the radula measures 2.8mm long (36%) and is composed of 36 rows of mature teeth. The median tooth is large in front (58m in width) where it bears a thin blade, and tapers posteriorly; its length is about 70 um. First lateral teeth are rectangular with a knobby pro- tuberance in the outer-anterior corner. Second (major) lateral has a bicuspid head which is about 45 wm in width THE VELIGER Vol. 21; No. 4 men " Figure 6 Callistochiton asthenes (Berry, 1919) Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected at White’s Point, California (CASG 938 607), original length 7.6mm and 70 um in the length of the largest (inner) cusp. Outer marginal teeth are elongated, 75 um long, 45 um wide. Type Material: Holotype, “preserved dry (S. S. B. 466), entered as Cat. No. 3913 in the author’s [S. S. Berry] col- lection” (BERRY, 1919b: 20). Paratypes at USNM (332 789), ANSP, CAS, and in A. G. Smith’s private collection [now at CAS]. Type Locality: ‘Under stones at low tide, White’s Point [33°42’N, 118°19’W], Los Angeles County, California” (BERRY, IgIgb: 20). Distribution: Callistochiton asthenes has been collected only in the general area of the type locality, Palos Verdes Peninsula, California, San Diego, California (SDNH 11637), and in the Coronados Islands, Guadalupe Island and Cedros Island, off the outer coast of Baja Califor- nia, Mexico. From the type locality, the following lots were studied: 14 specimens, leg. W. J. Raymond 1901 (CASG 38607) ; “part of the type lot,” leg. A. G. Smith 14-18 August 1916, 3 specimens (CASG 37998), and II specimens (CASG 43918) ; 10 specimens, July 1917 ° (SDNH 53830) ; 3 specimens, leg. E. PR Chace, 7 May 1950 (G. A. Hanselman Collection); 7 specimens ex George Willett Collection (UCLA 22402); 2 speci- mens, leg. S. Thorpe, July 1957 (LACM M-96). Recent attempts to collect the species at the type locality by my- self (April 1974) and others (G. A. Hanselman, in kitt., 17 August 1974) have failed. Vol. 21; No. 4 At Guadalupe Island (29°00’N, 118°16’W) Callisto- chiton asthenes was first collected by M. Woodbridge Wil- liams, 7 December 1946, as a lot of 80+ specimens from a “tide pool at the south end” of the island (CASG 32746). On a recent expedition to Guadalupe Island, Dr. Welton L. Lee and I collected C. asthenes at 2 stations: 13 speci- mens at Northeastem Anchorage, 30 December 1974 (AJF 210), and 60 specimens at Sealers’ Camp on the east side of the Island, 1 - 2 January 1975 (AJF 211). From Coronado del Sur, Islas Los Coronados [32°25’N, 117°15’W] only one lot was found, composed of 2 speci- mens, 5 and 6mm long, “ex Stephens Colln.” (SDNH 53867). From Cedros Island, Baja California, Mexico (28°10’ N, 115°15’W), only 1 specimen was examined (SDNH 23625). Callistochiton asthenes has only been collected in the intertidal zone, on the underside of rocks. Remarks: Callistochiton asthenes joins the list of chi- tons that brood the young in the branchial groove (Hy- MAN, 1967: 114). Several of the specimens in the type lot (CASG 43918), and in the first lot collected at Guada- lupe Island (CASG 32746) were observed to have several young specimens in the branchial groove. One young in the branchial groove of Callzstochiton asthenes 6.2mm long was measured as 0.30 X0.22mm in size; it did not seem to have a (visible) girdle. Another of these young specimens had only 7 distinct valves. The significance of the brooding habit as exhibited by C. asthenes and many other species of chitons is not immedi- ately apparent, although it has been regarded as “some stage in the development of viviparity” (DELL, 1965: 513) in chitons. It is a curious fact that none of the 73 speci- mens of C’. asthenes collected at Guadalupe Island on 30 December 1974 to January 1975, at 2 different stations (AJF 210, 211) had young in the branchial grooves. In length, Callistochiton asthenes does not usually at- tain 9mm; the largest specimen examined measures 10.0 mm long (SDNH 23625). Callistochiton leet Ferreira, spec. nov. (Figures 7, 8, 9, 10, 11, 12) Diagnosis: Very small (up to 8.5mm long) chitons, mostly dark red maroon in color (Figure 7). End valves with about 12, lateral areas with 2 - 3 radial ribs which are well defined and granose. Central areas with 6-9 longitudinal riblets per side, with no latticing. Mucro anterior. Girdle often banded maroon and white. Girdle scales oval, smooth surfaced with no striations. Sutural THE VELIGER Page 451 laminae sharp subquadrate. Slits corresponding to ribs; slit formula (holotype): 10-1 - 10. Description: Holotype—When dried and fully extended, it measures, including girdle, 8.1mm in length and 4.3 mm in width. Tegmentum uniformly dark “red wine” maroon. Anterior valve has 11 well defined radial ribs, strongly granose to the point of appearing tuberculated. These radial ribs are more like undulations of the teg- mentum than “added on” ribs; they are seen to undulate the anterior margin of the valve. In the intermediate valves, the lateral areas show 2 similar radial ribs, well separated at the periphery. The central areas have some 8 well defined, slightly granose longitudinal riblets per side; there is no latticing, the space between the longi- tudinal riblets is wide, but featureless except for the microgranular surface that characterizes the whole teg- mentum. The jugum is relatively smooth, 7. ¢., not ribbed. The posterior valve has an anterior mucro which, al- though well defined, is not too salient. The post-mucro area shows some 11 poorly marked, almost obsolete radial ribs. The articulamentum is white, somewhat translucid, the dark color of the tegmentum to shine through. The sutural laminae are moderately developed, sharp, thin, subquadrate. The sinus is relatively wide, and shows a minute sinusal lamina which, in some of the valves, dis- plays a few discrete pectinations. The eaves are short and solid. The insertion plates are cut into teeth, with a slit formula 10-1-10. The teeth are slightly thickened at the edges, and very slightly festooned. The slits correspond in position to the radial ribs (undulations) of the teg- mentum. The girdle is faintly banded maroon and white. The girdle scales are oval, closely imbricated, about 150m in length; their outer surface is micropunctate with a sieve-like appearance, and no striations or other ornamen- tations (Figures 8, 9, 10). There is a marginal fringe of spicules about 50 - 60 um long. The gills extend the whole length of the foot. The radula (Figure 11) measures 2.7mm in length, 2. €., 347% of the specimen’s length, and has 80 rows of mature teeth. The median tooth is quadrangular, meas- uring 37 wm in width by about 55 um in length; it bears a relatively large blade on its anterior edge. The first lateral has a pointed prolongation on its outer-anterior corner; but its overall configuration is very difficult to determine with certainty in the preparation at hand. The second (major) lateral is tricuspid. The head is about 25 pam in width and 35 um in the length of its middle (long- est) cusp. The outer-marginal teeth are somewhat round- ed, measuring 35 um in length by 25 wm in width. Page 452 as Soe = | ce ee Too pm. Figure 11 Callistochiton lee: Ferreira, spec. nov. Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Holotype, Guadalupe Island, Baja California, Mexico (AJF 211), original length 8.1 mm Type Material: Holotype (disarticulated valves, frag- ment of girdle, and mounted radula), is deposited at the California Academy of Sciences (CASIZ Type Series No. 705). Paratypes are deposited with the California Acad- emy of Sciences (CASIZ Type Series No. 706) ; Natural History Museum of Los Angeles County (LACM 1905) ; National Museum of Natural History (USNM 749083) ; Academy of Natural Sciences of Philadelphia (ANSP 346418) ; American Museum of Natural History (AMNH 183817). Color slides of paratypes are deposited at CASIZ, Color Slide Series. Type Locality: Guadalupe Island, on the outer coast of Baja California, Mexico, at “Sealers’ Camp,” about the midpoint on the east side of the island (29°o1’N, 118°13/ W), where the holotype and 6 paratypes were collected at low tide in less than 1m of water, by Welton L. Lee and Antonio J. Ferreira, 2 January 1975 (AJF 211). Remarks: Callistochiton leet is known only from the type locality. The specimens collected were all about the same color, a dark maroon, with white along the jugum and central areas in some specimens; in size they varied between 8.5 and 4.8mm in length, including girdle. With THE VELIGER Vol. 21; No. 4 C. asthenes, C. leet shares the habit of brooding the young. Four of the 7 specimens collected had minute juvenile chitons in the branchial grooves: one specimen had 2, one 3, one 8, and another 12 young. It is likely that there may have been more young chitons in the specimens col- lected, which may have fallen off during the collecting and preserving process that preceded examination. The young chitons measure about 500m in length; all are white. They show all 8 valves distinctly, but seem to have no visible girdle (Figure 12). The finding that C. leet broods the young seems all the more remarkable when it is considered that these specimens share the habitat with C. asthenes, a species also known for brooding its young; yet, among the 60 specimens of C’. asthenes col- lected at the same station (AJF 211), and 13 more col- lected at a nearby station (AJF 210), none was found to carry young in the branchial groove. This observation suggests that C’. leet and C. asthenes have different breed- ing seasons. Although Callistochiton leei seems to be closely re- lated to C. asthenes, they are absolutely distinct in color, sculpture of tegmentum, and girdle scales. Callistochiton leet is endemic to Guadalupe Island, as is Lepidozona guadalupensis Ferreira, 1978. Based on a list of the chiton species previously known on the island (A. G. Smrru, 1963), the finding of C. leez raises the per- centage of chiton endemism at Guadalupe Island to 20%. The species is called leet after Dr. Welton L. Lee, Chairman, Department of Invertebrate Zoology, Califor- nia Academy of Sciences, who shared in the collecting of the species at Guadalupe, and who has helped me gen- erously and enthusiastically in every phase of this and other works. Callistochiton gabbi Pilsbry, 1893 (Figures 13, 14, 15) Callistochiton gabbi Pispry, 1893, 14: 270 - 271; plt. 60, figs. 7-10 — Pirssry « Lowe, 1932: 129 — [?] BERGENHAYN, 1936: 282-284; text figs. 3a-3e[? misidentified] — Ken, Explanation of Figures 7 to 10 and 12 Figure 7: Callistochiton leei Ferreira, spec. nov. Paratype. 8.5mm long : Figures 8, 9, and 10: Callistochiton leet Ferreira, spec. nov. Holo- type. Girdle scales. SEM micrographs by Hans Bertsch, X 100, X 300 and X 600, respectively Figure 12: Callistochiton leei Ferreira spec. nov. Young specimen, about 500 «xm in length. SEM micrograph by Hans Bertsch XX 160 Tue VELIcER, Vol. 21, No. 4 [FERREIRA] Figures 7 to 10, 12 Vol. 21; No. 4 1958: 522; Amphineura fig. 27 — Linpsay, 1966: 347 - Torre in Keen, 1971: 873; Polyplacophora, fig. 28 — ABBOTT, 1974: 399 — A. G. SmiTH « FrrRrerra, 1977: 88 Callistochiton infortunatus Pirspry, 1893, 14: 266; plt. 59, figs. 37-42 — DaLL, 1909: 246 —- Pussry « Lowe, 1932: 129 — STRONG, 1937: 194 — STEINBECK & Ric- KETTS, 1941: 552; plt. 27, fig. 2 — A. G. Smiru « Gor- DON, 1948: 208 — Keen, 1958: 522; Amphineura, fig. 28 — Linpsay, 1966: 347 — THorpE in Keen, 1971: 873; Polyplacophora, fig. 29 — ABBOTT, 1974: 399 Callistochiton decoratus infortunatus. Dat, 1921: 194 — Oxproyp, 1927: 896 - 897 — A. G. SmiTH, 1947: 18 Callistochiton leidensis NIERSTRASZ, 1905: 143-1453 plt. 9, figs. 2-10 Description: Roundly arched to subcarinated chitons. Length up to 2cm. Color tan to rusty brown or dark green. Anterior valves with 8-10 well defined radial ribs separated by pitted spaces about as wide as the ribs; the radial ribs are somewhat triangular in cross-sec- tion, and often crowned by a series of 6 - 10 small knobs. Posterior valve rather variable in shape, from elevated and strongly convex to low and flat; mucro central; 7 - 10 radial ribs in the post-mucro area, usually not quite as well defined as those in the anterior valve. In the inter- mediate valves, the lateral areas are bicostate, the radial ribs with the same characteristics as in the anterior valve. Central area shows longitudinal riblets, 10 - 15 per side, finely latticed and with a tendency to diverge forward. The articulamentum is whitish to olivaceous, often with a dark brown discoloration at the apex of the end valves. Sutural plates subquadrate; sinus relatively narrow. In- sertion teeth short and with festooned free edges. Slit formula 9 - 1 - 8. Eaves solid and narrow. Girdle often Ce 100 zm =e Figure 14 Callistochiton gabbi Pilsbry, 1893 Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected at Guaymas, Sonora, Mexico (LACM 64-4), original length 16.0mm THE VELIGER Page 453 banded, covered with oval imbricating scales, about 150 pum in length, and with 12 - 15 fine striations (Figure 13). The radula is figured here for the first time (Figure 14). The specimen (LACM 64-4, Guaymas, Sonora, Mex- ico, leg. J. H. McLean, 30 January to 2 February 1964, at 5 - 13m), from a lot of 18 specimens, measures 16.0mm in length. The radula is 5.2mm long, that is 32% of the body length, and has 55 rows of mature teeth. The medi- an tooth is larger in front where it measures 88 ym in width, and has a small blade; the tooth narrows posterior- ly to about 43m. It is about 120m long. The first lateral teeth are somewhat quadrangular, often showing a small knob at the outer-anterior corner. The second (ma- jor) lateral teeth have a tricuspid head which measures about 60 wm in width, and 75 pmin the length of its middle (longest) cusp. Outer marginal teeth are elongated, a- bout 75 um long and 60 um wide. Type Material: Holotype (ANSP 118691) (Figure 15). Type Locality: “Gulf of California” (Pitssry, 1893, 14: 270), here restricted to Puertecitos (30°20’N, 114°39’W), Baja California, Mexico. Distribution: Throughout the Gulf of California, Mexi- co, to Ecuador. Callistochiton gabbi has been collected practically everywhere in the Gulf of California from San Felipe to Cabo de San Lucas, from Puerto Penasco, Sonora to Mazatlan, Sinaloa, including Bahia de Concepcion, and islands of Tiburon, Angel de la Guarda, Carmen, Danzante, San José, Espiritu Santo, Cerralvo, and others. Although with less abundance, C’. gabbi has also been found in southern Mexico, at Isla Isabella, Nayarit (LA CM-AHF 19; LACM-AHF 124-33), Banderas Bay (LA CM 71-83), Bahia Cuastocomate, Jalisco (LACM 68-41), Santiago Peninsula, Colimas (LACM 63-10), Zihuata- nejo (AJF 305) and Acapulco, Guerrero (AJF 307); Puerto Escondido (AJF 300) and Puerto Angel, Oaxaca (AJF 302); and farther south, Bahia Herradura, Costa Rica (LACM 75-52), Taboga Island, Panama (LACM 65-25), and Punta Ancén, Santa Elena Peninsula [2°20’ N, 80°53’W], Ecuador, its southernmost record (LACM 70-11 & 70-12, leg. J. H. McLean, 6-7 March 1970). Bathymetrically, C. gabbi has been found from low inter- tidal to “20 - 40 fathoms” [37 - 73m] (LACM 38-5). Remarks: Priissry (1893) described Callistochiton gab- bi 4 pages after describing C. infortunatus “from Car- penter MSS and unpublished drawings of his types” in the Manual of Conchology. While he attempted to distinguish Callistochiton gabbi from other similar species such as C. decoratus, C. elen- ensis, and even “Carpenter’s unfigured Ischnochiton ex- Page 454 pressus,” he failed to mention the extraordinary similari- ties between C. gabbi and C. infortunatus. Despite the awareness that both nominal species came from the same general locality, the Gulf of California and the Panamic province, Pilsbry’s differential diagnosis was limited to the profile of the tail valve which he described as “convex, mucro obtuse” in C. infortunatus, and “rapidly sloping backward from the front margin, mucro flat” in C. gabbi (Prrspry, 1893: 262; “Key to species of Callistochiton”). The examination of many lots of Callistochiton from the Gulf of California down to Central and South Ameri- ca has convinced me that Pilsbry’s species-group names, C. gabbi and C. infortunatus, refer to the same zoological species. The alleged differences in tail-valve profile and mucro appeared highly unreliable for distinguishing the 2 forms inasmuch as there are many specimens showing intergradation, often collected side by side at the same station; and no other characters, such as color, tegmental sculpture, articulamentum, girdle scales, or radula corre- lated in any significant manner with either morph. However, it is not without some justification that authors have adhered to, or at least left unquestioned Pilsbry’s notion of 2 species. Callistochiton gabbi is given to considerable intraspecific variation in color, sharpness of sculptural features, number of radial ribs in the end- valves, and profile and mucro of the tail valve. In color, specimens from the Gulf of California tend to be drabby looking, tan to olive, whereas specimens from the southern part of the range tend to be much more colorful, some- times in bright creamy browns, with reddish hues, even suffusions of cobalt-blue as was seen in a specimen from Taboga Island, Panama. In the number of ribs in the anterior valve, specimens from the Gulf of California tend to have 9 radial ribs (in a sample of 75 randomly selected specimens from the Gulf of California, 96% had g ribs in the anterior valve, 4% had 8), while specimens from southern locations tend to have 8 (in a sample of 16 specimens, 94% had 8, 6% had 9 ribs in the anterior valve). In both geographic populations the number of ribs in the posterior valve shows greater fluctuation. Of the samples mentioned, in the Gulf of California 10% of the specimens had 6 radial ribs, 30% had 7, 30% had 8, 25% had g, and 6% had 10; while in the southern range 6% had 6, 62% had 7, 19% had 8, and 12% had 9 radial ribs. In the case of the profile and mucro of the tail valve a definition of the morphs “infortunatus’ (ele- vated mucro, convex post-mucro) and “gabbz’ (low mucro, flat post-mucro) was made difficult as there were many intergradations. Considering only the extreme cases, 7. €., those specimens that clearly fit the definition Ce “gabbi” or “infortunatus,’ it was a simple matter to THE VELIGER Vol. 21; No. 4 conclude that the morph “gabbi” was virtually confined to the Gulf of California, whereas the morph “infortu- natus” was to be found throughout the range from the upper Gulf of California to Ecuador. In considering all the specimens available to me, there are many instances when the tail valve could not be so easily classified one way or the other, and all manners of intergradation of the mucro and the posterior valve’s profile could be seen between the two extremes, “infortunatus’ and “gabbi.” Often, these extremes and intergradations were found in specimens from the same lot; for instance, a lot of 31 specimens from Saladita Cove, Guaymas, Sonora (LACM 68-27) contained 18 specimens that would be classified as “gabbi,” 7 as “infortunatus,” and 6 as “ in between.” In a lot of 16 from Puertecitos, Baja California (LACM 62-19) only about 2 or 3 specimens would fit a rigorous definition of ’gabbi,” 1 or 2 that of “infortunatus” ; where- as the bulk of the lot, some 12 specimens, would have to be regarded as intermediates. As first reviser, I have selected the name Callistochiton gabbi for the species. Despite the fact that C. infortunatus has page priority, the name C. gabbi has the advantage of an already assigned type specimen (there is none for C. infortunatus), and a less ambiguous type locality and description. The examination of the holotype of C. gabbi was made possible through the kindness of Dr. Robert Robertson, Curator, Academy of Natural Sciences, Phila- delphia. Callistochiton leidensis NierstraB, 1905, described from a single specimen, 8mm long, collected at “Porta Santae Elenae” [? Ecuador] appears to be, from the de- scription and figures, a synonym of C. gabbi as here de- fined. Callistochiton colimensis (A. G. Smith, 1961) (Figures 16, 17, 18) Ischnochiton colimensis A. G. SmirH, 1961: 86-87; plt. 9, fig. 2 Callistochiton colimensis. THorPE in KEEN, 1971: 873; fig. 26 Ischnochiton lowei Pirspry in Pilsbry « Lowe, 1932: 129 [no- men nudum] Description: Oval, relatively high arched, somewhat carinated chitons (Figure 16). Length up to 2.5m. Color predominantly golden brown to cinnamon. Tegmental surface microgranular. Anterior valve with 11 - 13 strong- ly defined radial ribs, with a tendency to twin towards the periphery, crowned by minute, 100m in diameter, round tubercles. Lateral areas of intermediate valves usually bicostate; however, in large specimens a sulcus Vol. 21; No. 4 often appears in the rib dividing it radially. Radial ribs similar to those in anterior valve, crowned by minute tubercles, about 6 - 8 per rib. Central area has longitudinal riblets, about 10 per side, which remain parallel to the jugum or, as is more commonly the case, tend to converge somewhat forward. Riblets, separated by cross-ribbed spaces, become crowded towards the jugum. Jugal area longitudinally ribbed; there is no wedge-like figure on valve ii (such as seen in many species of Lepidozona). Mucro of posterior valve slightly but definitely anterior; post-mucro with 1o-11 radial ribs similar to those in anterior valve. Girdle, sometimes faintly banded, is covered with closely imbricated oval scales, up to 240 wm in length, displaying 1o - 16 fine striations (Figure Ty): Articulamentum white. Sutural laminae semioval and sharp; sinus shallow. Insertion plates with relatively sharp teeth, vaguely thicker at the edges, but showing no fes- tooning. Slit formula of paratype, 10-1 - 10; of another specimen examined, 9 - 1 - g. Slits correspond in number and position to the tegmental ribs. 100 pm | Figure 18 Callistochiton colimensis (A. G. Smith, 1961) Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected in Gulf of Tehuantepec, Mexico (Don Shasky collection), original length 7.5mm The radula is figured here for the first time (Figure 18). In a specimen 7.5mm long (Don Shasky Collection: “45 fathoms [82m], rocky bottom, San Juan Exped., Gulf of Tehuantepec [Mexico], July 10, 1963, Jeg. Don Shasky’’). the radula measures 2.75mm in length, and has 46 rows of mature teeth. Relative length, 37%. Median tooth wider in front, where it measures about 50 um in width, and bears a thin blade; posteriorly, it narrows rapidly to 25 um, tapering to a point. In length it measures about 60 pum. The first lateral teeth are not easily visualized in this particular preparation; they are somewhat quadrangular, and slightly angulated at the outer-anterior corner. The second (major) lateral teeth have a tricuspid head, about 38 um wide; the middle cusp, the longest, is about 50 um THE VELIGER Page 455 long. Of the other 2 cusps, the outer cusp is the larger; the inner cusp is small, hardly noticeable. Outer marginal teeth are somewhat elongated, about 53 um long and 38 pum wide. Type Material: Holotype (ANSP 152139); one para- type (CASG 12342). Type Locality: “Manzanillo [19°03’N, 104°20’W], Co- lima, Mexico,” collected by H. N. Lowe, 1930. Distribution: Callistochiton colimensis is quite rare, al- though its geographic range known at present extends from 23°N to 8°N. Specimens from the following stations were examined: “Pinacle north of Pescadero Canyon [23° 00’, 109°35.7'W, its northernmost record], off San José del Cabo, inside Inner Gorda Bank,” Gulf of California, Mexico, at 330 - 340m (CASIZ, leg. R. H. Parker, R/V Spencer F Baird, Vermillion Sea Expedition, 28 March 1959, 2 specimens); Los Arcos [20°40’N, 105°20’W], Banderas Bay, Jalisco, Mexico, at 5 - 24m (LACM 65- 15, leg. J. H. McLean & C. Miller, 22-24 March 1965, 1 specimen) ; Bahia Cuastocomate [19°14’N, 104°45'W], Jalisco, Mexico, 5 - 22m (LACM 68-41, leg. H. J. Mc- Lean & Oringer, 13-21 October 1968, 5 specimens) ; Manzanillo [19°03’N, 104°20’W], Colima, Mexico, inter- tidal (CASG 12342, leg. H. N. Lowe, 1930, 2 specimens, type lot, only paratype examined) ; Gulf of Tehuantepec [15°08’N, 93°23’W], Mexico, 82m (Don Shasky Collec- tion, Jeg. D. Shasky, San Juan Expedition, Sta. N-13, 10 July 1963, 6 specimens); Port Parker [10°58’N, 85°49’ W], Costa Rica, gm (LACM-AHF 468-35, 9 February 1965, 2 specimens); Bahia Elena [10°57’N, 85°46’W], Costa Rica, 26 - 53m (LACM 72-12, leg. P. LaFollette & D. Cadien, R/V Searcher, Sta. 392, 14 February 1972, 2 specimens) ; Isla Contadora [8°38’N, 79°02’W], Archi- piélago de las Perlas, Gulf of Panama, Panama, 2 - 6m, (AJF 224, leg. A. J. & N. J. Ferreira, 17 - 19 February 1975, I specimen). The bathymetric range of Callistochiton coltmensts established by these collections extends from the inter- tidal zone to 330 - 340m. Remarks: The similarities between Callistochiton colim- ensis and C. asthenes are noteworthy: (1) the tegmen- tum has similar texture; (2) the end-valves and the lateral areas of the intermediate valves have about the same number of radial ribs; (3) the radial ribs are crowned by a series of minute tubercles; (4) the mucro is anterior; (5) the central areas have about the same number of latticed longitudinal riblets; (6) the girdle scales are about the same size and striated. Yet the 2 spe- cies are quite distinct: (1) in size, C. colimensts reaches Page 456 lengths 3 times that of C. asthenes; (2) much warmer and brighter color can be seen in C. coltmensis; (3) the radial ribs are much better defined, more rounded, and stronger, with a tendency to twin in C. colimensts; (4) the longitudinal ribleis and latticing of the central areas are boldly sculptured in C. colimensis, only faintly visible in C. asthenes; (5) at the jugum, the longitudinal rib- lets are crowded but clearly present in C. colimensis, while invariably absent in C. asthenes; and (6) the girdle scales have more and finer striations in C. colimenses than in C. asthenes, and the pitted appearance of the striae, characteristic of the latter, is not present in the former. Still, young specimens of C. colimensis look remarkably similar to C. asthenes, and the differential diagnosis based on a single such specimen may prove rather difficult. In view of these similarities, it seems probable that the 2 spe- cies, C. colimensis and C. asthenes are closely related and share a common ancestral line. Callistochiton elenensis (Sowerby, 1832) (Figures 19, 20, 21) Chiton elenensis Sowersy in Broderip & Sowerby, 1832: 27 — MUtrer, 1836: 164 - Sowersy, 1840: 6, sp. no. 79 [spelled “ellinensis”]; p. 10, fig. 69 — [?] Reeve, 1847: sp. no. 116; plt. 19, fig. 116 (syn. of Chiton janetrensis Gray, 1828) — CarpENTER, 1857: 180, 318 Ischnochiton elenensis. CARPENTER, 1864: 552 - 553 [reprinted, 1872: 38, 39]; 1865: 275 [reprinted, 1872: 266] Callistochiton elenensis. Happon, 1886: 20 — Prussry, 1893, 14: 267 - 268 —- DatL, 1909: 246 —- Keen, 1958: 522 - FERREIRA, 1974: 1753 1976: 49 Lepidozona elenensis. THorPE in Keen, 1971: 871, Polyplaco- phora, fig. 33 (with syn. Lepidopleurus clathratus Car- penter, 1857, Ischnochiton expressus Carpenter 1865, and I. subclathratus Pilsbry, 1892) Callistochiton flavidus THIELE, 1910: 87 - 88; plt. 9, figs. 14 to 17 — KEEN, 1958: 522; Amphineura fig. 26 — [?] Rrc- HI, 1971: 133, 141 — FERREIRA, 1974: 175 Lepidozona flavida. THorrE in Keen, 1971: 875; Polyplaco- phora, fig. 34 THE VELIGER Vol. 21; No. 4 Ischnochiton expressus CaRPENTER, 1864: 552 [reprinted, 1872: 38] (nomen nudum); 1865: 275 - 276 [reprinted, 1872: 266 - 267] - THorPe in Keen, 1971: 871 (syn. of Lepidozona elenensis) Callistochiton expressus Pruspry, 1893, 14: 268-969 — KEEN, 1958: 522 Description: Relatively high arched, and carinated chi- tons. Length up to 11mm. Color tan to creamy brown, sometimes reddish or greenish. Anterior valve with 11 - 12 rounded to flattish ribs, in some specimens slightly granose; the ribs are more like undulations of the teg- mentum than “added on” features, the space between the “ribs” being as wide as the ribs themselves. The lateral areas of the intermediate valves are well marked by the presence of 2 radial ribs, similar to those found in the anterior valve; the anterior rib of the lateral areas is usually quite smooth in appearance while the posterior rib is often granose conferring a serrated appearance to the sutural space. The central areas have about 10 longi- tudinal riblets per side, which tend to diverge forwardly and are cross-ribbed very weakly in most specimens. The jugal area is usually ribbed, too. The posterior part of the valves iv to vii, particularly the latter, have an upswept appearance which gives the specimen a peaked profile. The posterior valve has a central, rather flat mucro; post- mucro area is depressed, with 8 - 11 radial ribs very poorly defined. The girdle is covered by oval, imbricating scales, about 100 um in length, with some 20 ribs separated by deep striations (Figures 19, 20). The articulamentum is whitish; often a brown discolor- ation may be seen at apex of valve viii. Sutural laminae are semioval and sharp; sinus quadrate. Insertion plates are cut into relatively sharp teeth; festooning is not obvi- ous, but there seems to be some thickening of the edges of the teeth. Slit formula of a specimen 8.5mm long (AJF 134, Masachapa, Nicaragua, leg. A. J. Ferreira, 23 Janu- ary 1974) isg-1-9. Radula of the same specimen (Figure 21) measures 2.7 mm in length (relative length, 32%) and has some 30 Explanation of Figures 73, 15) 19, 20, 22, 23, 25 Figure 13: Callistochiton gabbi Pilsbry, 1893. Girdle scales. SEM micrograph by Dennis Nichols and Myr! Stone Figure 15: Callistochiton gabbi. Holotype (ANSP 118691) X 100 Figures rg and 20: Callistochiton elenensis (Sowerby, 1832). Girdle scales. SEM micrographs by Hans Bertsch X goo and X 1000, respectively Figures 22 and 23: Callistochiton periconis Dall, 1908. Girdle scales. SEM micrographs by Hans Bertsch X 650 Figure 25: Callistochiton pulchellus (Gray, 1828). Lectotype (BM (NH) 197739) Tue VEuicEr, Vol. 21, No. 4 [FERREIRA] Figures 13, 15, 19, 20, 22, 23, 25 Figure 19 Figure 20 Figure 22 Figure 23 Vol. 21; No. 4 rows of mature teeth. The median tooth is wider anteriorly where it bears a thin blade, and measures 65 zm in width; posteriorly, it narrows to 25 um and then enlarges into a bulb 35 um in diameter. In length it measures about 90 pm. The first laterai teeth are quadrangular with a knobby protuberance at the outer-anterior corner. The second (major) lateral teeth have a unicuspid head, measuring about 50m in width, and 85m in length. The outer marginal teeth are quite elongated, 75 um long and 38 pam wide. WW 100 zm Figure 21 Callistochiton elenensis (Sowerby, 1832) Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected at Massachapa, Nicaragua (AJF 134), original length 8.5 mm ‘Fype Material: Sowerby’s type material of Chiton el- enensis is presumed lost or never designated. However, the species was illustrated, though poorly, by Sowerby in the Conchological Illustrations (fig. 69) [reprinted in Prissry, 1893, 14: pit. 59, figs. 27 - 28] and there seems to be no confusion in the current literature as to the zoo- logical species involved. The “‘exceptional circumstances” for the naming of a neotype (ICZN, Article 75) do not seem to be present, and none is designated herein. The whereabouts of Thiele’s type material of Callisto- chiton flavidus is unknown; it was not found at the Muse- um of the Humboldt- Universitat, Berlin (Dr. Rudolf Kili- as, in litt., 31 January 1977). The type material of Carpenter’s Ischnochiton expres- sus, if ever designated, could not be located at the U. S. National Museum of Natural History (Dr. J. Rosewater, in litt., 24 March 1977) or at the Academy of Natural Sciences of Philadelphia (M. Miller, in litt., 27 March 1978). THE VELIGER Page 457 Type Locality: “St. Elena [?Ecuador] and Panama” (Sowersy, 1832: 27). Distribution: Callistochiton elenensis seems to have a continuous distribution between the parallels 23°N and 2°S. The northernmost record is Playa Cerrito [23°20’N, 106°30’W], some 15 km N of Mazatlan, Sinaloa, Mexico (AJF 427, leg. A. J. & N. J. Ferreira, 7 July 1978, 6 specimens at 1 - 3m). The southernmost record is Punta Ancén (2°20'S, 80°53.5'W), Santa Elena Peninsula, Ecuador (LACM 70-12, leg. J. H. McLean, 7 March 1970, intertidally). Bathymetrically, the species ranges from the low intertidal zone to 18 - gom (CASG 23779). Remarks; Callistochiton elenensis has a sibling species in the Caribbean, C. portobelensis Ferreira, 1974, from which it differs by its (1) somewhat sharper tegmental features, (2) more angular and carinated appearance, (3) frequent presence of longitudinal riblets at the jugum, (4) “upswept” appearance of valves vi and vii, (5) thin- ner and more widely separated longitudinal riblets, and (6) ornamentation of the girdle scales [only evident in SEM micrographs, cf. Figures 19, 20 with FERREIRA 1974: figs. 3-5]. The synonymization of Callistochiton flavidus Thiele, 1910, is based upon the description and illustration of the species by Thiele. Although I have not been able to ex- amine Thiele’s type, it is quite clear that the specimen be- fore him, a single specimen 6mm long from Champerico [14°18’N, 91°55’W], Guatemala, was a juvenile of C. elenensis. The report of Callistochiton flavidus in Brazil (Ricut, 1971) could not be verified; I consider it extremely doubt- ful, and most likely a misidentification. The placing of Callistochiton expressus (Carpenter, 1865) in the synonymy of C. elenensts was already sug- gested by Carpenter himself when describing Ischnochi- ton (?var.) expressus, upon the examination of only 2 specimens, with the statement that they had “a strong general resemblance to I. elenensis’ (CARPENTER, 1865: 276). Now, with more material available, and a fuller appreciation of the extent of intraspecific variation in C. elenensis, the conclusion of conspecificity becomes obvious. On describing Chiton elenensis, SowerBy (1832: 27) remarked: ‘This is the Chiton Janeirensis, var.?, Gray. It is unquestionably a distinct species, as Mr. Gray hints it may be, from his Chit. Janetrensis.” Of course, Sowerby was correct in judging his Chiton elenensis to be distinct from Chiton janeirensis Gray, 1828[type locality: Rio de Janeiro, Brazil]; but he was incorrect in considering C. elenensis conspecific with “Chiton janetrenss (var.?) Page 458 Gray, 1828” [type locality: Valparaiso, Chile]. Thanks to the generosity of Aileen Blake, Mollusca Section, Depart- ment of Zoology, British Museum (Natural History), I had the opportunity of examining the type material of the species in question. As reported elsewhere (FERREIRA, 1978b), the examination of the type specimens revealed that Chiton janeirensis Gray, 1828, from Rio de Janeiro is indeed distinct from “Chiton janeirensis (var.?)” Gray, 1828, from Valparaiso; while the former species retains its name as type species of the genus Calloplax Thiele, 1909, the latter, also a Calloplax, appeared to be conspeci- fic with the later-named Callistochiton viviparus Plate, 1899. Likely, on the strength of SowERBy’s (1832) own state- ment that Chiton elenensis “is the Chiton Janeirensis, var.?, Gray”, REEvE (1847) was also led into confusion and error. In the Monograph, having already described Chiton janeirensis Gray, “Hab. Rio Janeiro” (plt. 15, sp. 80), Reeve “discovered” and, as such, described what he believed to be the authentic C. janeirensis, “Hab. Rio Janeiro. St. Elena, West Columbia [sic]; Cuming,” (op. cit.: plt. 19, sp. 116). Thus, he proposed the name C. sowerbianus [listed as species “80. Sowerby: Reeve” in the “Detail of Sculpture” part of the Monograph] for the species first described (sp. 80), and relegated Chiton elenensis Sowerby to the synonymy of the C. janeirensis Gray (sp. 116) as later described. The examination of the chiton specimens from the Cuming Collection that apparently caused Reeve to re- describe Chiton janeirensis proved to be of more than historical interest. Loaned for study through the gener- osity of Aileen Blake (BMNH), the lot consists of 5 specimens preserved dry and in good condition. The spec- imens, varying in length from 9.2 to 15.0mm, are accom- panied by a Museum label which reads: “B. M. (N. H.) reg.no.: / Chiton janeirensis Gray / FIGURED SPEC- IMEN / Rio Janeiro / H. CUMING colln. / 5 specs. Acc. no: 1829 / Conc. Icon. 4 Chiton / pl. XIX sp. 116 fig. 116, / (fig. = largest spec.), / Reeve.” On the face of the wooden tablet underneath the glued speci- mens, is handwritten in ink: “Leptochiton Janeirensis Gray / Rio Janeiro: St. Elena.” Examination of the specimens on the tablet reveals that 4 of them, including the figured one, conform in all respects to the present con- cept of Calloplax janeirensis (Gray, 1828) ; however, the remaining specimen, the smallest of the lot (9.2mm in length) is not C. janeirensis but Calloplax vivipara (Plate, 1902) [type locality, Urica, Chile; see FERREIRA, 1978], a species which, if girdle characteristics are dis- regarded, does resemble Chiton elenensis Sowerby. THE VELIGER Vol. 21; No. 4 Callistochiton periconis Dall, 1908 (Figures 22, 23, 24) Callistochiton periconis Daut, 1908: 355 - 356 — KEEN, 1958: 522 — THorpe in Keen, 1971: 873 (syn. of C. pulchellus (Gray, 1828)) - A. G. Smrrn, 1977: 217, 242-248 (syn. of C. pulchellus (Gray, 1828) ) “Chiton pulchellus Gray” - C. B. Apams, 1852: 243 - CarPENTER, 1857: 277; 1864a: 362 [reprinted, 1872: 198]; 1864b: 55% (reprinted, 1872: 38] [not Chiton pul- chellus Gray, 1828] “Chiton (Callochiton) pulchellus Gray.” Mércu, 1861: 176 [not Chiton pulchellus Gray, 1828] “Callochiton pulchellus: diagn. auct.” CARPENTER, 1857: 317; 1865: 276 [reprinted, 1872: 267] [not Chiton pulchellus Gray, 1828] “Callistochiton pulchellus (Gray).” Pitspry, 1893, 14: 271 to 273; pit. 60, figs. 1-6 — NrersTrRasz, 1905: 148; plt. 10, fig.18 — Prssry & Lowe, 1932: 129 — KEEN, 1958: 522; Amphineura, fig. 30 (with syn. Chiton bicostatus Orbig- ny, 1841) — THorPE in Keen, 1971: 873; Polyplacopho- ra, fig. 30 (with syn. Chiton bicostatus Orbigny, 1841; Callistochiton periconis Dall, 1908; C. fishert Dall, 1919) - A. G. SmirH & Ferreira, 1977: 88 [not Chiton pulchel- lus Gray, 1828] Callistochiton fisheri Daur, 1919: 512; 1921: 194 — Oxp- ROYD, 1927: 899 — LaRocgug, 1953: 12 — THORPE in Keen, 1971: 873 (syn. of Callistochiton pulchellus) — AssorT, 1974: 399 — A. G. SmirH, 1977: 217, 241 (syn. of C. pulchellus) Nomenclatural Comments: This common Central A- merica species has been referred to as Chiton pulchellus Gray, 1828, by authors following C. B. Apams (1852), Mércu (1861), and Pissry (1893). The examination of Gray’s type specimens of Chiton pulchellus (BMNH 197739) has conclusively demonstrated that Gray’s orig- inal material, collected at Arica, Chile, is distinctly dif ferent from Central American “pulchellus.” The first available name for the Central American spe- cies is Callistochiton periconis Dall, 1908. It is a tribute to Dall that, with the description of C. periconis, he was the first author to realize that the Central American spe- cies differed from C. pulchellus (Gray) in several impor- tant particulars. Unfortunately, under the lasting influ- ence of Pilsbry’s Manual, Dall’s observations were ignored and C. periconis relegated to the synonymy of the errone- ously called “pulchellus.” In this respect, it is interesting to note that even LeLoup (1953), having examined Gray’s syntypes at the British Museum (Natural History), did not notice the discrepancies involved as he spoke of “this species ... well described and figured by Pilsbry (op. cit.: 19). Vol. 21; No. 4 Original Description: “Animal small, of a pale brown- ish color with a narrow dark girdle covered with small, closely packed setose scales; middle valves with the sculp- ture of C. pulchellus (Gray) Pilsbry, from Peru, but dif- fering in the following particulars: the posterior ribs of the middle valves are transversely striated, not nodular, and do not serrate the suture; the anterior valve has thirteen rounded finely cross-striated ribs, the posterior has seven; this valve considerably overhangs the posterior part of the girdle, and the two anterior ribs are conspic- uously larger and stronger than the five between them. The gills are prolonged, reaching the second valve. Perico Island, Panama Bay, collected on the reefs by the ‘Alba- tross’ party, U.S. N. Mus. 110,763.” (DALL, 1908: 355 - 356). Expanded Description: High arched, round backed chitons, up to 1.5¢m in length. Color buffcream to very dark brown. Anterior valve with 10 - 13 strong rounded radial ribs, often cut by a vague series of concentric transverse growth lines. Posterior valve elevated, with a mucro markedly posteri- or; post-mucro area strongly convex with 6-8 rounded radial ribs similar to those in anterior valve. Intermediate valves with elevated lateral areas bearing 2 prominent radial ribs of which the posterior is usually wider, and sculptured with transverse tubercles that, in some speci- mens, confer a serrated appearance to the sutural spaces. Central areas with longitudinal riblets that become diag- onal and criss-cross, particularly in the midline, to form diamond-shaped pits. Girdle covered with strongly imbri- cating, oval scales, about 120um long; although under ordinary magnifications appearing smooth, the surface of the girdle scales, when examined in SEM micrographs, is seen to be covered by minute spherules (often eroded away) on the upper face, and vertical ribs on the lateral faces (Figures 22, 23). Articulamentum white, often with a bluish tint particu- larly accentuated in valve viii. Sutural laminae semioval, ’ becoming quadrate in valves vii and viii. Sinus wide and shallow, often minutely notched. Insertion plate cut into strong teeth; in the posterior valve, the insertion plate is not prominent (the teeth tending to point away from the midline) and exhibits minute denticulations, irreg- ularly disposed, inwardly. The massive thickness of the posterior valve makes its insertion plate, particularly in large specimens, less than conspicuous. The insertion teeth are often thickened at the edges and festooned, cor- responding in position and number to the ribs of the | tegmentum, except in larger specimens where often the number of teeth exceeds the number of tegmental ribs. In one of the specimens examined (AJF 218, Mensabé, THE VELIGER Page 459 Panama, leg., A. J. Ferreira, 12 February 1976, intertidal), 12.5mm long, the slit formula is 10-1 - 11. The radula of this specimen is 3.8mm long (30% of the specimen’s length), and comprises about 80 rows of mature teeth. The median tooth is slightly enlarged ante- riorly where it bears a small blade, and measures about 28 zm in width; from there it narrows slightly posteriorly, and then enlarges again to a width of about 30ym. In length, the tooth measures about 65 um. The first lateral teeth are subquadrate, about 80m long, 25m wide; they bear a small blade anteriorly. The second (major) lateral teeth have a long, bicuspid head; the outer cusp, the longer and larger, is about 80m long and 25 um wide, while the inner cusp is much shorter and inconspicu- ous. The outer marginal teeth are squarish, measuring about 50 um in length and in width. The radula of Call- tstochiton periconis is figured here for the first time (Fig- ure 24). oR Figure 24 Callistochiton periconis Dall, 1908 Radula: Median tooth, first lateral teeth, and heads (dorsal and profile views) of second lateral teeth. Specimen collected at Men- sabé, Panama (AJF 218), original length 12.5 mm Type Material: Holotype (USNM 110763) ; color slide, photograph of the specimen taken by A. G. Smith, at CASIZ Color Slide Series no. 1927. Callistochiton fisheri Dall, 1919: 6 syntypes (USNM 110353); color photograph of 4 of the specimens taken by A. G. Smith, at CASIZ Color Slide Series no. 1933. Type Locality: Perico Island [8°55’N, 79°31’W], Pan- ama Bay, Panama. Distribution: The range of Callistochiton pericénis is relatively narrow, extending only between parallels 11°N and 6°N. The northernmost record of the species is a small bay at “Hacienda Nacascolo,” 2km N of San Juan del Sur (11°15’N, 85°52’W), Nicaragua (AJF 138, leg., Page 460 A. J. & N. J. Ferreira, low intertidal zone, 26 January 1974). The southernmost record is Punta Cruces (6°40'N, 77°33'W), Colombia (CASIZ 006297, leg., D. P. Abbott, Te Vega Cruise 18, sta. JT-20, intertidal, 2 May 1968), with many stations in between. The bathymetric range extends from the intertidal zone to 30 fathoms [55m] (AJF Collection, Bahia Santa Elena, Costa Rica, R/V Searcher, Sta. 391 trawling, leg. A. J. Ferreira, February 1972). The largest specimen of C. periconis examined is 14.5mm long, including girdle (ANSP 243632, reef at San Francisco, near Panama [City], leg., Pilsbry, 17 May 1929). Remarks: The placing of Callistochiton fisheri in the synonymy of C. periconis is based upon the observations of A. G. SmrrH (1977) who examined and photographed the 6 specimens in the syntype series. The study of the color slides of 4 of the syntypes shows conclusively that C. fishers and C. periconis are conspecific. As pointed out by A. G. SMITH (op. cit.: 241), the statement that C. fishert had been collected in the Aleutian Islands must be considered as erroneous. Callistochiton pulchellus (Gray, 1828) (Figures 25, 26) Chiton pulchellus Gray, 1828: 6 (reference is made to plt. 3, fig. 9, never published but on file at BM[NH], teste A. Blake, in litt. 28 November, 1977) [not Chiton pulchellus Philippi, 1844] - Reeve, 1847: sp. 153, plt. 23, fig. 153 — PazTEL, 1873: 80 Callochiton pulchellus. H. & A. Apams, 1858: 471 Calistochiton pulchellus. DaLL, 1909: 246 — BoupeT, 1945: 134 — LELouP, 1953: 18-19; fig. 3 [misinterpreted]; 1956: 46 — StuarRno, 1959: 144, 146 [Not Callistochiton pulchellus ex auctore treating Panamic specimens] Chiton bicostatus Orpicny, 1841: 486; plt. 81; figs. 7-9; 1854: 54 Callistochiton carmenae A. G. SmirH & FERREIRA, 1977: 87 to 88; figs. 10-11 Callistochiton shuttleworthianus Pilsbry. BERGENHAYN, 1936: 284-285; text figs. 3f-3g — Kaas, 1972: 100-101 — G6TTING, 1973: 253 [not C. shuttleworthianus Pilsbry, 1893] Original Description: ‘6. Chiton pulchellus, n. — Tes- td oblonga, elongata, subcarinatd, albido-lutescente; ared centrali puntulatd, laterali costis duobus latis, rugulosis; valuis terminalibus inaequaliter radiatim costatis. Icon. t. 3.f9. Inhab. Arica, Peru, Rev. W. Hennah. Brit. Mus. Shell oblong, elongate, slightly keeled, yellowish white; end valves distantly unequally radiately ribbed; lateral THE VELIGER Vol. 21; No. 4 area of the middle valves with two broad regular ribs; central area closely and deeply punctured. Margin yel- lowish white, with very minute bran-like scales. The ribs of the lateral areae are rarely bifid. Length 34, breadth ¥ of an inch.” (Gray, 1828: 6). As mentioned before, plate 3 of Spicilegia Zoologica was not published. However, thanks to the generosity of Aileen Blake, Mollusca Section, Department of Zoology, British Museum (Natural History), I was able to study a xerox copy of that unpublished plate in the repository of the British Museum, and verified figure 9 as corresponding to Gray’s description, above as well as to the syntype series (BMNH 197739). Detail figure of the posterior valves is given by REEVE (1847: sp. no. 153). Both Gray’s figure and Reeve’s en- larged detail are reproduced by Pmssry (1893) in plt. 60 as figs. 1 and 2, respectively. Description: The type material (BMNH 197739) was examined on a loan secured through the kindness of Aileen Blake (BMNH), October 1977. The vial contains a single label which reads: “British Museum (Natural History) / Chiton pulchellus Gray / Syntypes / Reg. No. 197739 / 3 specs.” An invoice accompanying the specimens states further, “Arica, Peru, Rev. Hennah.” The syntype series consists of 3 specimens, dry, flat, in fairly good condition; they show vestiges of glue and paper to which they were probably attached in the past. All 3 specimens are a uniform tan color, and show a diffuse black smudge along the jugum, obviously ex- ternally acquired. The specimens measure, including the girdle, 8.7 X 5.3mm; 8.4 X 5.0mm; and 6.6 X 3.5mm. The largest specimen (Figure 25) here designated as lectotype, shows about 15 radial rows in the anterior valve; these ribs are very low in profile. The posterior valve has a central mucro, low, but slightly pointed; the post-mucro area is flat to slightly concave, showing some 11 radial ribs, low and weakly defined. The intermediate valves are subcarinated. The lateral areas are well de- fined; they bear e relatively flat radial ribs, the posterior rib weakly but definitely crenulated. The central areas are pitted; the pits are mostly round, and become much less accentuated, almost obsolete at the jugum. The girdle is covered with very small, seemingly striated scales. The 2 paralectotypes, although smaller in size, have virtually the same characteristic as the lectotype. Among the chiton material collected in Chile by Dr. James H. McLean, 1975, 2 lots of Callistochiton pulchel- lus (Gray, 1828) were recognized. One (LACM 75-10) consists of 26 specimens, preserved in alcohol, bearing the locality label “Intertidal, Pozo Toyo (S of Iquiqrv:), Tarapaca Prov., Chile (20°25’S, 70°10.5’'W), leg. J. H. Vol. 21; No. 4 McLean (sta. 1), 29 Sept., 1 Oct. 1975;” the other (LA CM 75-12), consists of a single specimen, with the label “Intertidal, Iquique, marine lab. Universidad del Norte, Tarapaca Prov., Chile, (20°15.5’S, 70°08’W), leg. J. H. McLean (sta. 3), 30 Sept., 2 Oct., 1975.” Thanks to the generosity of Dr. James H. McLean, Curator, Mollusks, Natural History Museum of Los Angeles County, I was permitted to study these specimens, and so add to the understanding of C. pulchellus. The specimens examined are all rather uniform in color, creamy white, and in size. The longest specimen (LACM 75-12) measures 10.2mm in length, the smallest, 5.6mm. The mean size of all specimens studied (a total of 30, in- cluding the syntypes) is 7.7mm in length. The number of radial ribs in the anterior valve is 12 in most specimens, although varying from 1o to 13; in the posterior valve the number of ribs is 8 - ro. In the lateral areas there are always 2 radial ribs. In most specimens the radial ribs are rather low and weakly defined, particularly in the post-mucro area of the posterior valve. The mucro of valve viii is clearly central in all specimens, and the post- mucro flat to concave. The central areas have round pits, as if made by the intercrossing of virtual diagonal riblets; the pits are deeper on the sides than in the jugal area. Actually, in most specimens, all tegmental features, the radial ribs, and the pitted central areas, are rather sub- dued, even subobsolete in some specimens. The girdle scales are oval, about 120jzm long and 40 pm high. They show about 20 vertical rib-like formations on the lateral surfaces which define that many striae in between, and minute spherical globules on the upper surfaces. The girdle scales are well figured by LeLoup (1953: fig. 3) apparently from material obtained from the syntype specimens. The underside of the girdle is covered by rectangular, overlapping scales, featureless, measuring about 50 4m by 1oum. Figure 26 “=> Callistochiton pulchellus (Gray, 1828) 100 zm rsh Radula: Median tooth, first lateral teeth, and head of second lateral tooth. Specimen collected at Pozo Toyo, Chile (LACM 75-10), original length 7.0mm THE VELIGER Page 461 The radula of a specimen 7.0mm long (LACM 75-10, Pozo Toyo, Chile) measures 2.3mm in length, that is, 33%. It has about 46 rows of mature teeth. The median tooth is quite small (Figure 26), about 154m wide, ending anteriorly by a rather round edge with a small blade. The first lateral teeth, difficult to see, seem to end anteriorly by a similar round edge. The second (major) lateral teeth have a unicuspid head, about 65 um long and 25 um wide; the inner aspect of the shaft, just below the head, bears a long protuberance, 20 by 8 um, pointing inwardly and anteriorly, obviously very fragile. The outer marginal teeth are 45 um long and 25 um wide. The slit formula of this specimen is 9 - 1 - 10. Insertion teeth correspond in position to the ribs of the tegmentum. Gills abanal, about 18 plumes per side, extend to about 80% of the foot, becoming progressively larger posterior- ly. Type Material: Syntypes (BMNH 197739), 3 speci- mens, the largest designated lectotype herein. With the kind permission of the Trustees of the British Museum (Natural History), a photograph of Gray’s specimen is published [© Trustees, BM(NH)] here for the first time (Figure 25). Callistochiton carmenae A. G. Smith e Ferreira, 1977: Holotype (CASIZ, Type Series no. 696) ; paratypes (CA SIZ Type Series no. 58248, and in the private collection of G. & L. Burghardt). Type Locality: “Arica [18°29’S, 70°20’W], Peru [Chile}” (Gray, 1828: 6). Distribution: Callistochiton carmenae A. G. Smith & Ferreira, 1977, is here regarded conspecific with C. pul- chellus (Gray, 1828). Thus, the distribution of C. pul- chellus is known from 4 localities, 3 on the mainland (Ari- ca, Pozo Toyo, and Iquique, in Chile), and the Galapagos Islands (about 0°30’S, 90°30’W), Ecuador. Probably bet- ter collecting along the west coast of South America will produce new collecting sites, and a clearer view of the distribution of the species. However, C. pulchellus does seem to be far from abundant. Dati (1909: 246) indi- cates he examined specimen(s) collected at Islay [17°03’ S, 72°08’W], Chile. But Letoup (1956) did not find the species among the collections obtained during the Lund University Chile Expedition, 1948-1949; and Ma- RINCOVICH (1973) does not report the presence of C. pul- chellus at Iquique, Chile. So, for the present C. pulchellus southernmost record is Pozo Toyo (20°25’S) ; its north- ernmost record is the Galapagos Islands, and on the main- land, Islay (17°03’S). Bathymetrically, Callistochiton pulchellus is ki own only from the intertidal zone. Page 462 Remarks: In addition to the type material, another lot of Callistochiton carmenae has come to my attention: It consists of 6 specimens, averaging 7.8mm in length, col- lected 42 January 1938, intertidally, at Black Beach (1° 16’26”S, 90°29'42”W), Charles Island, Galapagos, Ecua- dor (LACM-AHF 806-38). Upon the realization of the true nature of C’. pulchellus (Gray, 1828), a side by side comparison led to the conclusion that C. carmenae and C. pulchellus were conspecific. In all respects of signifi- cance — color, size, tegmental features, articulamentum, girdle scales, radula — the C. carmenae from the Gala- pagos is identical with the C. pulchellus from the main- land. The only noticeable distinction between the 2 geo- graphic populations, albeit so far a constant one, lies in the much sharper tegmental features of C. carmenae when compared with C. pulchellus: The radial ribs of the anterior and posterior valves, as well as those from the lateral areas, and the pitted appearance of the central areas of the intermediate valves, are much more strongly defined, more incisely sculptured in the Galapagos than in the mainland populations. Such sole distinction is, in my opinion, of less than specific significance. Conceivably, the Galapagos population of C. pulchellus could be considered distinct enough to warrant the name carmenae to be re- tained with subspecific rank; yet, I find it more satis- factory to regard those differences in the intensity of the tegmental sculpture as an expression of geographic vari- ation, and relegate the nominal C. carmenae to the syn- onymy of C’.. pulchellus. DISCUSSION In the Eastern Pacific, 10 species of Callistochiton are here recognized, 5 in the north temperate region, 4 in the tropical region, and 1 in the south temperate region. Their distribution, illustrated in Diagram 1, demonstrates the faunal break known to exist at about Magdalena Bay (24°30'N) on the outer coast of Baja California, Mexico. As it had been found for Lepidozona species (FERREIRA, 1978), not a single species of Callistochiton crosses that barrier in either direction. Another faunistic break is demonstrated at the southern boundary of the tropical region. The only species of Callistochiton in the south temperate region, C. pulchellus, is recorded in the Gal4- pagos Islands which, under the influence of the Humboldt Current may be regarded as an extension of the warm temperate region. The taxonomic position of other nominal species of “Callistochiton” from the Eastern Pacific appears as fol- lows: Callistochiton aepynotus Dall, 1919 has been shown THE VELIGER Vol. 21; No. 4 to be a synonym of Mopalia sinuata Carpenter, 1864 (A. G. SmitH, 1977). Callistochiton duncanus Dall, 1919 has been assigned to the genus Calloplax Thiele, 1909 (A. G. SMITH & FERREIRA, 1977) ; and so has Callistochiton vivi- parus Plate, 1899 (FERREIRA, 1978b). Callistochiton shutileworthianus Pilsbry, 1893 had been reported from Isla Floreana, Galapagos Islands, Ecuador, by BERGENHAYN (1937) ; the study of Bergenhayn’s single specimen, available through the courtesy of Dr. Tor A. Bakke, Zoological Museum of Oslo, Norway, clarified the questionable identification (A. G. SmMirH & FERREIRA, 1977). Bergenhayn’s Gal4pagos specimen is to be referred to Callistochiton pulchellus (Gray, 1828). The genus Callistochiton has a world-wide distribution, although nowhere is it represented by as many species as in the Eastern Pacific. In the Western Atlantic only 2 Callistochiton crassicostatus Callistochiton pulchellus Callistochiton colimensis Callistochiton gabbi Callistochiton periconis Callistochiton elenensis Callistochiton lees Callistochiton asthenes Callistochiton decoratus 40° N Point Conception 30° N MEE Callistochiton palmulatus | a O..as | - ey /Cabo San Lucas 20° N 10° N 20° S Figure 27 Geographical Distribution of the Species of Callistochiton Dall, 1879 in the Eastern Pacific Vol. 21; No. 4 species of Callistochiton are known, C. shuttleworthianus Pilsbry, 1893 and C’.. portobelensis Ferreira, 1976. Judging from the description and illustrations, C. incurvatus Le- loup, 1953 (type locality, “prés de Pernambouc’”’) is a junior synonym of Ischnochiton pectinatus (Sowerby, 1840), as already noted by Ricrr (1967) who neverthe- less, ignoring the distinctly different characteristics of the girdle scales, preferred to assign the species to Callisto- chiton (Ric, 1967, 1971). In the Eastern Atlantic no species of Callistochiton have been reported. SaBeLti (1971) pointed out that Chiton pachylasmae Monterosato, 1879, allegedly collec- ted in the Strait of Messina, Mediterranean Sea, does properly belong to Callistochiton. Examination of photo- graphs of the single specimen of C. pachylasmae in the repository of the Museo Zoologico di Roma, kindly sent to me by Dr. Sabelli, Istituto di Zoologia, Universita di Bologna, confirms the appropriateness of its assignment to Callistochiton. But the locality of C. pachylasmae remains in serious doubt in view of the fact that there seems to be no record of its having been collected again in the Medi- terranean or elsewhere (Dr. B. Sabelli, in itt. 10 January 1977)- Although I have had no opportunity to study the several other species of “Callistochiton” described from elsewhere in the world, judging from their illustrations or descrip- tions, or both, it seems reasonable to accept the validity of the following: Callistochiton jacobaeus (Gould, 1859), in Japan; C. adenensis (E. A. Smith, 1891), in the Red Sea; THE VELIGER Page 463 C. antiquus (Reeve, 1847), in South Australia; C. grani- fer Hull, 1923, in Australia (Queensland) and New Cale- donia; C. indicus Leloup, 1953, in the Chagos Archipela- go, Indian Ocean; C. carpenteri NierstraB, 1905, Rio de Janeiro, Brazil; C. madagassicus Thiele, 1910 [?==C. adenensis (E. A. Smith, 1891)], from Madagascar; C. philippinarum Thiele, 1910, in the Philippines. A comparison of the characteristics of the differen species of Callistochiton in the Eastern Pacific permits some observations regarding the girdle scales and the ra- dula. All species of Callistochiton in the Eastern Pacific have relatively small girdle scales, rarely exceeding 150 to 200m in length. In their shape and ornamentations, however, 3 basic morphologies appear: (1) striated scales, in which the striations would more properly be called steep undulations of the scale surface (C. palmula- tus, C. crassicostatus, C. decoratus, C. asthenes, C. gabbi, and C. colimensis); (2) microgranular and smooth sur- faced scales (C. leet); and (3) laterally ribbed scales with spherules on the upper surface (C. pulchellus and C. periconis), or without spherules (C. elenenszs). The taxonomic value of the radula in chitons is still a matter of controversy. Although it is clear now that in chitons radular characteristics are not species-specific, there is every indication that its careful study will prove useful to the understanding of the species and their pos- sible relationships. Thus, it is informative to compare some relevant characteristics in the radula of Callisto- chiton im the Eastern Pacific (Table 1). Table 1 Meristic characteristics of the radula of species of Callistochiton Dall, 1879, in the eastern Pacific. Radula ; outer-marginal teeth Species Length relative rows of median tooth major — of spm length teeth width lateral cusps length width length/width mm Yo no. ym no. pm pm ratio Callistochiton palmulatus 16.2 39 40 95 2) 115 75 1e5) crassicostatus 8.0 35 48 125 2 140 100 1.4 decoratus 21.0 32 70 100 2 100 80 13 asthenes 7.6 36 36 58 2 1D 45 Leo leet 8.1 34 80 37 3 35 25 1.4 gabbi 16.0 32 55 88 3 75 60 183 colomensis U3) 37 46 50 3 53 38 1.4 elenensis 8.5 32 30 65 1 75 38 2.0 periconts 1:2%5 31 80 28 2 50 50 1.0 pulchellus 7.0 33 46 15 1 45 25 1.8 2 Page 464 As far as the length of the radula is concerned, no essential differences were found among the species in question: All species had a radula with about the same relative length, that is between 31% and 39% of the specimen length, a difference which, considering the smallness of the sample cannot be regarded as significant. The counting of the number of rows of “mature teeth” elicited some interesting differences among species: Al- though the number of rows cannot be taken literally since the human error in counting “mature rows’ is considerable (perhaps as high as 10%), it came to light that certain species (Callistochiton periconis, C. leet) have a much larger number of rows (and consequently much shorter outer marginal teeth) than others (C. elenensis, C. asthenes) As to the median tooth of the radula, the majority of the species have the same kind of tooth, enlarged anterior- ly where it bears a sharp blade, and tapering posteriorly (Callistochiton palmulatus, C. crassicostatus, C. decora- tus, C. asthenes, C. gabbi, and C. elenensis) ; but in C. leet the median tooth is quadrangular, and in C. pul- chellus and C. periconis it is rectangular and elongated. The median tooth varies in the width of the anterior blade from 125 um in C. crassicostatus, to only 15 4m in C. pul- chellus, and 28 pm in C. periconis. The first lateral teeth in all specimens examined are very difficult to visualize. Here more than anywhere else in the study of the chiton radula, we wish for the day when SEM micrographs could be easily obtainable. In most of the species, the first lateral tooth is somewhat quadrangular with a knobby protuberance in the anterior- outer corner [the same morphology found in Lepidozona which, together with the very similar median tooth, likely accounted for THIELE’s (1929) treatment of the 2 groups as subgenera of Lorica]. Such first lateral teeth are found in Callistochiton palmulatus, C. crassicostatus, C. decora- tus, C. asthenes, C. gabbi, and C. elenenszs, although the knobby formation at the anterior-outer corner is not al- ways aS Conspicuous. The second (major) lateral teeth in the Callistochiton of the Eastern Pacific have a head which may be (1) uni- cuspid (C. elenensis, C. periconis, and C. pulchellus) ; (2) bicuspid (C. palmulatus, C. crassicostatus, C. decor- atus, and C. asthenes), or (3) tricuspid (C. leez, C. gab- bi, and C. colimensis). Lastly, the outer-marginal teeth whose significance in the study of the chiton radula has not been hitherto fully appreciated, show considerable variation from species to species. Two extremes may be distinguished: (1) Spe- cies with markedly elongated, 7. e., near twice as long as THE VELIGER Vol. 21; No. 4 wide, outer-marginals (Cailistochiton elenensis, C. pul- chellus, and C. asthenes), and (2) species with squarish, 2. €., length nearly as great as width, outer-marginals (C. periconis). ACKNOWLEDGMENTS For their valuable help in the various phases of this work, I wish to express my appreciation to Dr. Peter U. Rodda, and Barry Roth, Department of Geology, California Academy of Sciences; Dr. James H. McLean, Natural History Museum of Los Angeles County; Dr. Joseph Rose- water, National Museum of Natural History; Dr. Robert Robertson, and Melanie Miller, The Academy of Natural Sciences of Philadelphia; William E. Old, Jr., American Museum of Natural History, New York; the late Dr. George E. Radwin, and George A. Hanselman, Natural History Museum of San Diego; and to Glenn and Laura Burghardt, Oakdale; Salle Crittenden, San Francisco; and Dr. Donald R. Shasky, Redlands, California. I fur- ther extend my appreciation to Aileen Blake, British Mu- seum (Natural History); Dr. Tor A. Bakke, Zoological Museum of Oslo, Norway; Dr. R. Kilias, Zoologisches Museum, Humboldt University, Berlin; and Dr. Bruno Sabelli, Istituto di Zoologia, University of Bologna, Italy. I am particularly grateful to Dr. Hans Bertsch, Chami- nade University, Hawaii (now of the San Diego Museum of Natural History), and to Dennis Nichols and Myrl Stone of Beta Research Oceanographic Laboratories, San Jose, for their SEM micrographs; and to Dr. Welton L. Lee, and Dustin Chivers, Department of Invertebrate Zoology, California Academy of Sciences, for their critical reading of the manuscript, and the steady support gener- ously given to all my work. Literature Cited Assort, Rosuxt TuckEr 1974. American Seashells. and ed., Van Nostrand Reinhold Co., New York; 663 pp., 4000+ text figs.; 24 plts. (in color) Apams, CHaries Baker 1852. Catalogue of shells of Panama; with notes on their synonymy, station, and geographical distribution. Ann. Lyc. Nat. Hist., New York 5: i- vilit+334 pp. Apams, Henry « ARTHUR 1853-1858. The genera of recent Mollusca, arranged according to their organization. John Van Voorst, London, 1: vi-xl+1-484; 2:1 661; 3: pits. 1-138 [Chitons: 1854. 1: 467 - 484] BERGENHAYN, J. R. M. 1936. Polyplacophoren von den Galapagos Inseln. Norv. Zool. Exped. Galapagos Isls., 1925, cond. by Alf Wollebaek. Meddel. Zool. Mus. Oslo, No. 49, Contr. XIV (Nytt Mag. Naturvid. 76): 273 - 286; 3 text figs. (29 December 1736) Vol. 21; No. 4 Beary, SAMUEL STILLMAN 1907. Molluscan fauna of Monterey Bay, California. 21 (2): 17-22 21(3): 34-35 a1 (4): 39-47 (16 August 1907) a1 (5): 51-52 (18 September 1907) 1919a. Preliminary notices of some new west American chitons. Lorquinia 2 (6): 4-7 (6 January 1919) 1919b. Notes on west American chitons, II. Proc. Calif. Acad. Sci. (4) 9 (1): 1-36; pits. 1-8 (16 June 1919) 1922. Fossil chitons of western North America. Proc. Calif. Acad. Sci. (4)11 (18): 329-526; 11 text figs.; 16 plts. (16 May 1922) 1926. Fossil chitons from the Pleistocene of San Quintin Bay, Lower California. Amer. Journ. Sci. 12: 455 - 456 (November 1926) Bouvet Rommet, IsaBEL 1945. Los quitones Chilenos. Rev. Chil. Hist. Nat. 48: 122-140 Broperip, WitLt1AM JoHN & Gerorce BretTINGHAM SOWERBY (1°) The Nautilus (21 June 1907) (6 July 1907) 1892-1833. | Characters of new species of Mollusca and Conchifera, collected by Mr. Cuming. Proc. Zool. Soc. London for 1832: 25 - 33 (21 April 1832) 50-61 (5 June 1832) 104 - 108 (31 July 1832) 124-126 (14 August 1832) 173-179 (14 January 1833) 194 - 202 (13 March 1833) Burcu, Joun Quincy # THomas Apams Burcu 1943. List of species dredged on shale bed off Del Monte, Monterey, California, 10-35 fathoms, in August 1940. Minutes Conchol. Club South. Calif. no. 2: 5-6 (J. Q. Burch, ed.) (April 1943) 1943. The Timm’s Point Pleistocene horizon of San Pedro, California. Minutes Conchol. Club. South. Galif. no. 2: 7-9 (J. Q. Burch, ed.) (April 1943) Burcu, THomas ApaMs 1942. Dredging off Redondo Beach, California. Minutes Conchol. Club South. Calif. no. 17: 5-11 (J. Q. Burch, ed.) (November 1942) BurcHarnt, Gienn E. 2 Laura E. BurcHARDT 1969. A collector’s guide to West Coast chitons. Spec. Publ. No. 4, San Francisco Aquar. Soc., Inc., 45 pp.; 4 color plts. 7 text figs. (November 1969) Carpenter, PHitip PEARSALL 1857. Catalogue of the collection of Mazatlan shells in the British Museum: collected by Frederick Reigen. PP. i- iv, ix- xvi, 1 - 552. British Museum, London (1 August 1857) 1864a. Review of Prof. C. B. Adam’s “Catalogue of the Shells of Pana- ma,” from thé type specimens. Proc. Zool. Soc. London for 1863: 339 - 369 (April 1864) (reprint: 1872, Smithson. Misc. Coll. 10 (252): 173 - 205 [original pagination at top of page] 1864b. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Rprt. Brit. Assoc. Adv. Sci., 33 (for 1863): 517-686 (post 1 August 1864) (reprint: 1872, Smithson. Misc. Coll. 10 (252): 1-172; [original pagination at top of page]) 1865. Description of new species and varieties of Chitonidae and Ac- maeidae, from the Panama collection of the late Prof. C. B. Adams. Proc. Zool. Soc. London for 1865 (1): 274-277 (June 1865) (reprint: 1872: Smithson. Misc. Coll., 10 (252): 263 - 268 [original pagination at 1872. The mollusks of western North America. Embracing the second report made to the British Association on this subject with other papers; reprinted by permission, with a general index, Smithson. Mise. Coll. no. 252: xii+325+ index, 121 pp. CwHacez, Emery PERKINS 1917a. Shell collecting at San Pedro. Lorquinia 1 (6): 42- 44 (January 1917) 1917b. _— Fossil chitons. Lorquinia 2 (4): 30-31 (November 1917) Cuacz, Emery Pernins & Evsm Marcaret Hersst CHace r919. An unreported exposure of the San Pedro Pleistocene. Lor- quinia 2 (6): 1-3 (January 1919) Cooper, James GraHam 1867. | Geographical catalogue of the Mollusca found west of the Rocky Mountains between 33° and 49° north latitude. San Francisco (State Geol. Surv. & Towne & Bacon): 40 pp. (post-April 1867) Dati, Wittiam HEarey 1879. Report on the limpets and chitons of the Alaskan and Arctic regions, with descriptions of genera and species believed to be new. Proc. U. S. Nat. Mus. 1: 281-344; 5 pits. (15-19 February 1879) 1908. 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 “Albatross,” during 1891, Lieut.-Com- mander Z. L. Tanner, U.S. N., commanding. XXXVII. Reports on the THE VELIGER Page 465 scientific results of the expedition to the eastern tropical Pacific, in charge of Alexander Agassiz, by the U. S. Fish Commission steamer “Albatross,” from October, 1904, to March, 1905, Lieut.-Commander L. M. Garrett, U. S. N., commanding. XIV. The Mollusca and Brachio- poda. Bull. Mus. Comp. Zool. 43 (6): 205 - 487; plts. 1-22 (22 October 1908) 1909. Report on a collection of shells from Peru, with a summary of the littoral marine Mollusca of the Peruvian zoological province. Proc. U. S. Nat. Mus. 37 (1704): 147-294; plts. 20- 28 (24 November 1909) 1919. Descriptions of new species of chitons from the Pacific coast of America. Proc. U.S. Nat. Mus. 55 (2283): 499-516 (7 June ’19) 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 unfigured species. U.S. Nat. Mus. Bull. 112: 1-217; 22 pits. (24 February 1921) Ferrema, ANTONIO J. 1974. The genus Lepidozona in the Panamic province, with the descrip- tion of two new species (Mollusca : Polyplacophora). The Veliger 17 (2): 162 - 180; 6 pits. (1 October 1974) 1976. A new species of Callistochiton in the Caribbean. The Nau- tilus go (1): 46-49; 5 text figs. (30 January 1976) 1978a. The genus Lepidozona (Mollusca : Polyplacophora) in the tem- perate eastern Pacific, Baja California to Alaska, with the description of a new species. The Veliger 21 (1): 10-18; 5 plts.; 3 text figs. (1 July 1978) 1978b. The genus Calloplax Thiele, 1909 (Mollusca: Polyplacophora) in the Americas. Bull. South. Calif: Acad. Sci. 77 (2): 56-64 (30 November 1978) G6orttino, Kraus Jircen 1973. Die Polyplacophora der karibischen Kiiste Kolumbiens. Arch. Molluskenk. 103 (4/6): 243 - 261; plts. 8-11; 6 text figs. (30 November 1973) Gou.p, Aucustus Appison 1859. On the shells collected by the United States Exploring Expedi- tion. Proc. Boston Soc. Nat. Hist. 7 (11): 161-165 (Dec. *59) [reprint: 1862, Otia Conchologica, Boston, Gould & Lincoln, 256 pp.] Gray, Joun Epwarp 1828. Spicilegia Zoologica; or original figures and short systematic de- scriptions of new and unfigured animals, Part I. 8 pp.; 6 pit. British Museum (1 July 1828) Happon, Aurrep C. 1886. Report on the Polyplacophora collected by H. M.S. Challenger during the years 1873 - 1876. Challenger Rprts. 15 (43): 1-50; pits. 1-3 Hutt, A. E Bassett 1923. | New Australian Polyplacophora, and notes on the distribution of certain species. Part I. The Austral. Zoolog. 3: 157 - 166; pits: 24-26 Jounson, Myrtie EvizanetH & Harry James SNOOK 1927. Seashore animals of the Pacific coast. McMillan Co., New York, pp. i-xiv+1-659; 11 color plts.; 700 text figs. (reprint: 1967, Dover Press, New York) i Kaas, P 1972. Polyplacophora of the Caribbean region. Studies on the fauna of Curasao and other Caribbean islands. 41 (137): 162 pp.; 247 text figs. ; 9 pits., Martinus Nijhoff The Hague (July 1972) Keen, A. Myra 1958. Sea shells of tropical west America: marine mollusks ftom Lower California to Colombia. 1st ed. Stanford Univ. Press, Stanford, California. viii+624 pp.; ca. 1700 figs.; 10 color pits. (5 Dec. 1958) 1971. Sea shells of tropical west America: marine mollusks from Baja California to Peru. 20d ed. Stanford Univ. Press, Stanford, Cali- fornia. xiv+ 1064 pp.; ca. 4000 figs.; 22 color plts. (1 September 1971) La Rocquz, AURELE 1953- Catalogue of the Recent Mollusca of Canada. Mus. Canada 129: xi+ 406 pp. Lzxoup, Evctne ; : J 1953. Caractéres anatomiques de certain Callistochitons. Bull. Inst. Roy. Sci. Nat. Belg. 29 (30): 1-18; 11 text figs. (May 1953) 1956. Polyplacophora. Reports of the Lund University Chile Expedi- tion 1948-49 No. 27. Lunds Univ. Arsskrift. N. E, Avd. 2, 52 (75). Kungl. Fysiografiska Sallskapets Handl. N. F 67 (15): 94 Pp-; 53 text figs. Licut’s Manual 1941. 1st ed. — see Licht, Sor FELty 1954. 20d ed. — see Liou ef al. 1975- 3° ed. — see SmiTH # CaRLTON Bull. Nat. Page 466 Liout, Sot Fe.ty 1941. Light’s manual. Laboratory and field text in invertebrate zoolo- gy, 13%t ed.: pp. i-vii; 1-232; 136 text figs. Liout, Sor Ferty, RatpH INcrRAM SmiTH, FRANE ALOyYsIUs PITELKA, Donatp Putnam ApsspoTT & Frances M. WEESNER 1954. Intertidal invertebrates of the central California coast. xii-+ 443 pp.; 138 text figs. Univ. Calif. Press, Berkeley, California Linpsay, GroroE E. 1966. The Gulf Islands expedition of 1966. Sci. (4) go (16): 309-355; 23 text figs. McLzan, James HamiLton 1969. Marine shells of southern California. Los Angeles Cty. Mus. Nat. Hist. Sci. Ser. 24, Zool., no. 11: 104 pp.; 54 text figs. (Oct. ’69) Mércu, Orro ANDREAS Lowson 1861. Beitrage zur Mollusken-Fauna Central Amerika’s. Malako- zool. Blatter 7: 170-213 Minuer, Tu. 1836. Synopsis novorum generum, specierum et varietatum testace- orum viventium anno 1834 promulgatorum. 256 pp. Nigrstrass, Huco Frieprica 1905. Die Chitonen der Siboga-Expedition. 48, 112 pp.+addendum; 8 plts. OLpDROYD, IDA SHEPARD 1924. Marine shells of Puget Sound and vicinity. Univ. Wash. Puget Sound Biol. Sta. 4: 272 pp.; 49 pits. (March 1924) 1927. The marine shells of the west coast of North America. Stan- ford Univ. Press, Stanford, Calif. 2 (3): 605-941; pits. 73 --108 [Chitons: 848 - 925] Orsiony, Arcipg Cuartes Victor DrssaLings D’ 1841. Voyage dans YAmérique Méridionale (1826 - 1839). 5 (g): Mollusques [Chitonidae: pp. 482 - 489] Orcutt, CHarLes RUSSELL 1885. Notes on the mollusks of the vicinity of San Diego, Cal., and Todos Santos Bay, Lower California. Proc. U.S. Nat. Mus. 8: 534 - 544 (10 October) ; plt. 24 (21 October) ; 545-552 (26 October) 1915. Molluscan World. vol. J, San Diego [Private], 208 pp.; index 62 pp. (post 1 August 1915) PagTe., FriepricH 1873. Catalog der Conchylien-Sammlung. Berlin, 172 pp. Parmes, KaTHering EvaNcg.ing Hitton VAN WINELE 1945. Molluscan types in the Carpenter collection in the Redpath Museum. The Nautilus 38 (3): 97-102 (19 February 1945) 1958. Type specimens of marine Mollusca described by P. P. Carpenter from the west coast (San Diego to British Columbia). Geol. Soc. Amer., Mem. 76: viiit+376 pp.; 35 pits. (8 December 1958) Puiuipr1, RupotpHus AMANDUS 1836-1844. Enumeratio Molluscorum Siciliae. Proc. Calif: Acad. (30 December 1966) Siboga-Expeditie, no. 2: 303 pp.; plts. 13-28 [1844] Pirapry, Henry Avoustus 1892a. Polyplacophora. In: Tryon, Manual of Conchology, 14: 1-64; pits. 1-15 (25 July 1892) 1892b. Polyplacophora. In: Tryon, Manual of Conchology, 14: 65 - 128; plts. 16-30 (25 November 1892) 1893a. Polyplacophora. In: Tryon, Manual of Conchology, 14: 129 - 208; plts. 31 - 40 (25 February 1893) 1893b. Polyplacophora. In: Tryon, Manual of Conchology, 15: 209 - 350+1 - xxxiv; plts. 41 - 68 (1 July 1893) 1893c. Polyplacophora. In: Tryon, Manual of Conchology 15: 1 - 64; plts. 1-10 (16 November 1893) 1894. Polyplacophora. In: Tryon, Manual of Conchology, 15: 65-132; plts. 11-17 (19 March 1894) Pirspry, Henry Aucustus « Hrersert NeLtson Lowe 1932. West Mexican and Central American mollusks collected by H. N. Lowe, 1929-31. Proc. Acad. Nat. Sci. Philadelphia 84: 33 - 144; 17 pits. (21 May 1932) Piate, Lupwic H. 1898-1902. Die Anatomie und Phylogenie der Chitonen. In: Fauna Chilensis, 274 vol., Zool. Jahrb., Suppl. V (1): 15-216; plts. 2-11 (20 December 1899) THE VELIGER Vol. 21; No. 4 Ranve, Lovett Avoustus 1847. Monograph of the genus Chiton. In: Conchologia iconica or illustrations of the shells of molluscous animals. 4: 28 plts. with 194 figs. A t 18. Rica, GILBERTO es ” 1967. S6bre Polyplacophora do litoral brasileiro. Pap. Avuls. Zool. (Sao Paulo), 20 (9): 85-98; 47 text figs. (11 July 1967) 1971. Moluscos poliplacéforos do Brasil. Pap. Avuls. Zool. (So Paulo), 24 (9): 123-146; 60 text figs. (10 March 1971) SaBELLI, BRuNo A. 1971. Revisione del Chiton pachylasmae Monterosato. Boll. Zool. , Atti del XL Conv. dell’ U. Z.1., Garda (Verona) 27 Sept. to 1 Oct., 1971, vol, 38 SuitH, ALLyN GoopwiIn 1947. Check-list of West North American marine mollusks: Class Am- phineura, order Polyplacophora. Minutes Conch, Club South. Calif. (J. Q. Burch, ed.) 66: 17-19 (Jan.-Feb. 1947) 1961. Four species of chitons from the Panamic province (Mollusca: Polyplacophora) . Proc. Calif. Acad. Sci. (4) 30 (4): 81 - 90; plts. 8-9 (go April 1961) 1963. A revised list of chitons from Guadelupe Island, Mexico (Mol- lusca : Polyplacophora).: The Veliger 5 (4): 147-149 (1 April) 3966. The larval development of chitons (Amphineura). Proc. Calif. Acad. Sci. g2 (15): 433-446; 11 figs. (24 October 1966) 1977. Rectification of west coast chiton nomenclature (Mollusca : Polyplacophora). The Veliger 19 (3): 215-258 (1 January 1977) SsatH, ALLYN GoopwIN & ANTONIO J. FERREIRA 1977. | Chiton fauna of the Gal4pagos Islands. The Veliger 20 (2): 82-97; 4 pits. (1 October 1977) SxatH, ALtyN Goopwin & MacKenzie Gorpon, Jr. 1948. The marine mollusks and brachiopods of Monterey Bay, Cali- fornia, and vicinity. Proc, Calif. Acad. Sci. (4) 26 (8): 147+245; plts. 3, 43 4 text figs (15 December 1948) Snare, Epoar ALBERT 1891. On a collection of marine shells from Aden, with some remarks upon the relationship of the molluscan fauna of the Red Sea and the Mediterranean. Proc. Zool. Soc. London 1891: 390 - 436; pit. 33 (October. 1891) SoatrH, Ratew I. & James T. Cartton 1975. Light’s manual. Intertidal invertebrates of the central Califor- nia coast. 3rd ed. pp. i-xvilit1 - 716; illust. Univ. Calif. Press, Berke- ley Sowersy, Gzorce BreTTiINcHAM 2nd 1841. The Conchological Illustrations. A catalogue of the Recent spe- cies of chitons [1840]: pp. 1-10; plts. 38-45, figs. 1-55; plts. 159 to 176; figs. 56 - 155 STEINBECK, JOHN & Epwarp F. RIcKEITS 1941. Sea of Cortez. x+598 pp.; 40 plts.; 2 charts [reprint: 1973, P P Appel, New York] Strono, Ancamatp McCxiure 1937. Marine Mollusca of San Martin Island, Mexico. Proc. Calif. Acad. Sci. (4) 23 (12): 191 - 194 (30 December 1937) Stuarpo, Josz 1959. Ensayo de una clave para familias y generos chilenos de Poly- placophora, con generalidades del grupo e inclusion de algunas especies comunes. Invest. Zool. Chil. 5: 139 - 148 (2 November 1959) Ture.e, JOHANNES 1893. Das Gebiss der Schnecken zur Begriindung einer natiirlichen Classification. 2: 351 - 401; plts. 30-32. Polyplacophora 1909-1910. Revision des Systems der Chitonen. Stuttgart. 132 pp.; 10 pits. 1929. | Handbuch der systematischen Weichtierkunde. Erster Teil, Lori- cata; Gastropoda. I: Prosobranchia (Vorderkiemer). pp. 1-376, Jena, Tryon, Grornce WASHINGTON, Jr. 1883. Structural and systematic conchology: an introduction to the study of the Mollusca. 2: 430 pp.; pits. Wi.iett, Gzoror 1937- A new Callistochiton from Lower California. 31 (1): 25-26; pit. 2, fig. 13 The Nautilus (3 July 1937) Vol. 21; No. 4 THE VELIGER Page 467 A New Panamic Mitrella (Mollusca : Gastropoda ) WILLIAM PITT! Field Associate, Department of Geology, California Academy of Sciences, San Francisco, California 94118 AND ROY KOHL Curator, Department of Geology, Humboldt State University, Arcata, California 95521 (1 Plate) ON ONE Low TIE series, from January 27, to February 2, 1975, William and Lois Pitt sampled the intertidal mollus- can fauna in the vicinity of Puntarenas, Puntarenas Prov- ince, Costa Rica. On January 29 and 30, 1975, they sampled the fauna at Punta Coralillo, Bahia de Caldera. The substrate was rocky rubble above, and muddy sand below the mean low tide line. Prominent members of the molluscan fauna included Fissurella (Cremides) virescens Sowerby, 1835; Scurria mesoleuca (Menke, 1851) ; Tegu- la (Agathistoma) verrucosa McLean, 1970; Thais (Vasu- la) melones (Duclos, 1832); Acanthina brevidentata (Wood, 1828); Cantharus (Gemophos) gemmatus (Reeve, 1846) ; and Anachis (Costoanachis) fluctuata (Sowerby, 1832). Also occurring in abundance was a new species of Mitrella that is described herein. The animals were found aggregated on the undersides of rocks near the mean low tide line. A deep water port is under construc- tion adjacent to the type locality. There will be a break- water about 2km to the north, angling from the shore of Bahia de Caldera in a northwesterly direction. Although the type locality will not be within the completed harbor, some alteration of local conditions due to construction could be expected. : Museums mentioned in the text are the following: AMNH, American Museum of Natural History, New York; BMNH, British Museum (Natural History), London; CAS, California Academy of Sciences, San Francisco; UCR, University of Costa Rica; FMNH, Field Museum of Natural History, Chicago; MCZ, Museum of Compar- ative Zoology, Harvard University, Cambridge, Mass. ; 1 Permanent address: 2444 38 Avenue, Sacramento, CA 95822 HSU, Humboldt State University, Arcata, California; LACM, Los Angeles County Museum of Natural History; USNM, National Museum of Natural History (Smithson- ian Institution), Washington, D. C.; ANSP, Academy of Natural Sciences, Philadelphia; SDMNH, San Diego Mu- seum of Natural History; TU, Tulane University. The following private collections are also cited: Sally Bennett Collection, Phoenix, Arizona; Helen DuShane Collection, Whittier, California; William Pitt Collection, Sacramento, California; Tom Rice Collection, Port Gamble, Washing- ton; Donald Shasky Collection, Redlands, California; and Carol Skoglund Collection, Phoenix, Arizona. BUCCINACEA CoLUMBELLIDAE Mitrella Risso, 1826 Mitrella loisae Pitt & Kohl, spec. nov. (Figures 2a, 2b, 3a, 3b) Diagnosis: A small, smooth Mitzella differing from other Panamic members of the genus in having a unique color pattern of irregular dots and wavy lines. Description of Holotype: Shell small, slender, smooth, with 7 slightly convex whorls; ground color yellow; nuc- lear whorls 3, first 2 white, third yellow; first postnuclear whorl with faint brown wavy lines; second wt orl with white band below suture, interrupted by wavy lines that merge into irregular dots; third whorl with narrow band of irregular brown dots below suture, followed by white Page 468 band which is interrupted by wavy brown lines that merge into irregular dots; body whorl with narrow band of ir- regular dots below suture, followed by a white band which is interrupted by wavy brown lines which in turn merge into a series of irregular dots and wavy lines, all elongated in direction of growth; outer lip thickened, denticulate within; inner lip smooth except for 2 low folds; base of columella with about to spiral lirations. Height 5.3mm, diameter 2.2mm. Type Locality: North side of Punta Coralillo, Bahia de Caldera, Puntarenas Province, Costa Rica (9°54’N; 84°44’ W) (Figure 1), about 20km S of the city of Punt- arenas. There were 575 specimens collected by William and Lois Pitt on January 29-30, 1975. Type Material: Holotype, CAS 60193. Paratypes (6) each to the following: CAS 60194-60199, AMNH, BMN H, UCR, FMNH, MCZ, HSU, LACM, USNM, ANSP, SDMNH, TU, DuShane Collection, Pitt Collection, and Skoglund Collection. The remaining specimens from the original lot are in the Pitt Collection. Variation among specimens in the original lot is from 4.4 to 5.2mm in height. Some of the paratypes are juveniles as evidenced by the thin, non-denticulate outer lip. Referred Material: 1) Playa Jaco, Puntarenas Prov- ince, Costa Rica (9°36’ N, 84°38’ W) (Bennett and Rice Collections, 1 specimen each, collected by Sally Bennett and Tom Rice on 25 April 1975); 2) El Rubio and Punta Mero, Tumbes Province, Peru (3°54’S, 80°53’ W) (Shasky Collection, 21 specimens; SDMNH, 43 spec- imens; LACM, 39 specimens, collected by Donald Shasky, James H. McLean and Mario Pefia on 16 April 1972); 3) south of Bocapan, Tumbes Province, Peru (3°44’S, 80°46’ W) (SDMNH, 2 specimens; LACM 5 specimens, collected by Donald Shasky, James H. McLean, and Mario Pena on 12 April 1972); 4) Playas (reef at west end of beach), south side of Santa Elena Peninsula, Ecuador (2°38’S, 80°25’ W) (Shasky Collection, 3 specimens; LACM, 2 specimens, collected by Donald Shasky and James H. McLean on 8 March 1970); 5) Cape San Francisco, Ecuador (approx. 0°37’ N, 80°10’ W) (LACM I specimen, collected on 23 February 1938, Hancock, bottom sample No. 586). Discussion: Mitrella loisae is similar to M. pulchrior (C. B. Adams, 1852), but is more slender and differs in THE VELIGER Vol. 21; No. 4 color pattern in the following ways: M. pulchrior has rectangular white spots below the suture, separated by vertical dark blotches; whereas M. lotsae has a white band below the suture, interrupted by wavy brown lines elongated in the direction of growth; M. pulchrior has clear-cut, fine dots on the body whorl; whereas dots on the body whorl of M. loisae are irregular in shape and in many cases merge into wavy lines. Other Panamic Mitrella treated in KEEN (1971) were not considered close enough to require comparison. A southern form of Mitrella loisae from the above mentioned locations in Ecuador and Peru differs in having a paler ground color, and the wavy lines on the lower part of the body whorl tend to break into wavy dotted lines. It is noteworthy that although extensive collecting has been done in Panama, there were no specimens of Mitrella loisae from that area in any of the major collections that we checked. Mitrella pulchrior has been reported only from Pana- ma (KEEN, 1971: 593). However, material that we have examined extends its range north to Matanchen, Nayarit, Mexico (CAS, collected by Faye Howard; LACM, col- lected by Gale Sphon), and south to Playas, Santa Elena Peninsula, Ecuador (Shasky Collection; LACM, collected by Donald Shasky, James H. McLean, and Mario Pefia)- Etymology: ‘The specific name honors the wife of the senior author who has given continual encouragement and been of much assistance in the field. ACKNOWLEDGMENTS We thank Mr. Barry Roth (CAS) for his help in the preparation and review of this paper; the late Dr. George Radwin (SDMNBH) for his initial help; Dr. Donald Shas- ky for the loan of his material; Dr. James H. McLean (LACM) for the loan of material and reading this paper; Sr. Fernando Rudin of the Instituto Geografico National of Costa Rica for the maps and aerial photograph; and Mr. Bert Draper, Museum Associate, LACM, for the photography. Literature Cited Kaen, A. Mypa 1971. Sea Shells of Tropical West America; marine mallusks from Baja California to Peru. and ed. Stanford Univ. Press, Stanford, Calif i-xiv + 1064 pp.; ca. 4000 figs.; 22 color plts. (1 September 1971) Explanation of Figures 7 to 3 Figure 1: Aerial view of Punta Coralillo from 5000m; arrow indicates the type locality of Mitrella loisae Figure 2a: Ventral view of holotype of Mitrella loisae; Figure 2b: Dorsal view of the holotype; height 5.3mm Figure 3a: Mitrella loisae, southern form, from El Rubio, and Punta Mero, Tumbes Prov., Peru; ventral view, height 5mm (CAS) Figure 3b: Dorsal view of the same specimen Tue VELIGER, Vol. 21, No. 4 [Pirt « Kout] Figures 7 to 3 Figure 2a Vol. 21; No. 4 THE VELIGER Page 469 Evidence for an Additional Littorina Species and a Summary of the Reproductive Biology of Littorina from California TALBOT MURRAY Graduate School of Oceanography, University of Rhode Island, Kingston, RI 02881 (2 Text figures) INTRODUCTION STUDIES OF THE REPRODUCTIVE patterns of California littorinaceans revealed 2 morphologically distinct types of egg capsules produced by females identified as Littorina scutulata Gould, 1849. These egg capsules differed in their shape, dimensions, number of eggs per capsule and in the size and location of the hatching pore through which the veligers emerged. The developmental rate within the capsules was also found to differ between the 2 types. The occurrence of dimorphic penes among male L. scutulata further suggests that this taxon, as construed on the basis of shell morphology, is a composite of 2 morphologically similar species. How significant are such differences in this group of snails? It has been shown by various authors, including WarpLe (1965), Borkowski & Borkowski (1969), RosEWATER (1970) and BANDEL (1974), that egg capsule morphology is a discrete species character. BoRKOWSKI & Borkowski (of. cit.) further found that both shape and size of egg capsules were a “good species discriminator” for 3 Littorina species of a similar shell morphology that occur together on rocky intertidal shores in southeastern Florida. It is also evident from the studies of RoSEWATER (op. cit.) and BANDEL (op. cit.) that the utility of egg capsule morphology as a species character can be extend- ed to faunal provinces rich in littorine species. Differen- ces in embryonic and larval development can similarly be cited as species-specific traits. In males, the morpholo- gy of the penis has also been successfully employed in de- lineating littorinid species by Appotr (1954), WHIPPLE (op. cit.), ROSEWATER (op. cit.), as well as others. Shells in littorinids, however, demonstrate greater vari- ability than do egg capsules or soft parts. STRUHSAKER (1968) has reviewed several examples of intraspecific variation within the Littorinidae. Her experimental work has further indicated that, for at least one species, varia- tion in shell sculpture has a genetic basis, while survivor- ship of the 2 morphs depends upon the environment. Therefore, asynchronous environmental changes along a shoreline may serve to encourage variability among shells in a population. However, it is equally probable that a given environment may encourage convergence of shell characters of co-occurring species. The second hypothesis would serve to explain how 2 species might be considered as a single highly variable one, as present evidence sug- gests is the case for Littorina scutulata. METHODS Adult specimens of Littorina scutulata were collected from a variety of intertidal habitats from San Diego, California, U.S. A., north to Vancouver Island, British Columbia, Canada. Snails were packed damp in plastic bags, and hand-carried or air mailed in padded mailing bags. Spe- cimens thus could be obtained throughout much of the species’ range within 1 to 7 days without significant mor- tality. Upon arrival, snails were placed in Carolina Stack- ing Culture dishes (inside diameter 10.5cm), half filled with filtered sea water at 15°C. The dishes of snails were then placed in a water bath of the same temperature and checked daily for egg capsules. Water was changed daily. Egg capsules were sorted on the basis of capsule shape and transferred to Stender dishes (inside diameter 5-3cm) half filled with filtered sea water. Ege capsules were examined at 24-hour intervals until hatching. Fol- lowing hatching, each egg capsule was examined and Page 470 point of hatching noted. The diameters of the hatching pore and of the capsule surface containing the pore were measured. Individual spawning records, for fecundity estimates, were obtained by placing individual snails in the Stender dishes half filled with water and recording the presence or absence of egg capsules at 24-hour intervals. If spawning did not occur within 7 days, that snail was replaced; otherwise, snails were maintained until egg capsule pro- duction ceased. The number of eggs per capsule was re- corded for all capsules produced in the laboratory. This study was conducted at the Pacific Marine Station, Dillon Beach, California, from April until August 1973, and was continued at the Graduate School of Oceano- graphy, University of Rhode Island, Narragansett, Rhode Island, during August 1974. EGG CAPSULES ann FECUNDITY The egg capsules produced by Littorina from California are planktonic. Within these capsules, the embryos develop to veligers before hatching. The number of eggs, and hence embryos, per capsule varies with species. In L. plan- axis Philippi, 1847, no more than a single egg per capsule has been found in the several thousand examined. The number of eggs per capsule in L. scutulata, however, shows variability among capsules. This variation is stable for each capsule type, if either the range or mean of the number of eggs per capsule is considered. The differences in egg capsule morphology between the 2 L. scutulata morphotypes are described below. Littorina scutulata, Type 1: These egg capsules (Fig- ure 1A) are slightly greater than 1mm in maximum diam- eter. They consist of 2 biconcave discs separated by a central chamber containing the eggs. The overall appear- ance resembles that of an automobile wheel. The number of eggs contained in these capsules may range from 4 to 41 eggs, although 17 to 32 is usual. Variation in number of eggs per capsule is summarized in Table 1 for the sta- tions studied. The salmon-colored eggs prior to the first cleavage are 95-7/4m in diameter. Each egg is enclosed within a trans- parent membrane 116.5um in diameter. Fecundity esti- mates were not made for this group of L. scutulata. Littorina scutulata Type Il: The egg capsules de- scribed by Buckianp-Nicks e¢ al. (1973), for L. scutu- lata are of this type. These capsules (Figure 1B) are shaped like inverted saucers and may contain 1 to 14 embryos, although 3 to 1o is usual (see Table 1). The egg capsule is slightly smaller than the Type I and contains fewer eggs. The eggs are salmon-colored, 105m in diam- THE VELIGER. Vol. 21; No. 4 Table 1 The range and mean of the number of eggs per capsule spawned by Type I and II Littorina scutulata during 1973. : Type I Type II Approximate Source N. Latitude range mean |range mean Ucluelet, British Columbia 49°00’ = — 1-4 2.9 Anacortes, Washington 48°30! — — present Newport, Oregon 44°40! 4-35 17.3 = = Howard Creek, Mendocino Cty. California 39°45! =— = 1-14 10.4 Sea Ranch, California 38°42’ 14-35 25.3 7-9 79 Dillon Beach California 38°10! 5-34 22.6 = = San Luis Obispo, California 35°25! present 3-13 7.3 Pismo Beach, California 35°10’ 10-28 20.8 = — Gaviota, California 34°25! 6-41 23.8 | 3-6 4.4 S. Laguna Beach, California 33°32! 19-40 32.8 | 3-12 7.6 San Diego California 32°45! 7-32 18.0 | 2-11 4.2 eter and contained within an egg membrane 130.5um in diameter. Both Type I and Type II capsules are readily distin- guished from the capsules of Littorina planaxis by size, number of eggs and capsule morphology; see Figure 1 and ‘Table 3. Fecundity estimates for isolated Type II Littorina scu- tulata from central and northern California indicate a lower egg production and longer period of spawning than reported by BuckLanp-Nicxs et al. (1973), for Puget Sound, Washington. They report that 3 females produced 896, 1034 and 1398 egg capsules within a 2- week period before capsule production ceased. These capsules contained from 3 to 4 eggs each so that total egg production per female was between 9 900 and 13 300. In the present study, 4 females from Mendocino County, California, isolated in 1973, produced 156 to 235 capsules with a combined egg production of 7220 eggs. Normal- izing these data to a per-snail fecundity, the California snails were only half as fecund as the individuals from Puget Sound, although spawning lasted for 4 weeks with- Vol. 21; No. 4 Figure 1 Pelagic egg capsules of California species of Littorina A) Littorina scutulata Type I, hatching pore, through which veli- gers emerge, forms on the lower capsule surface B) Littorine scutulata Type Il, hatching pore forms on the upper capsule surface C) Littorina planaxts Scale is 100 ym out reinseminating the females, 2 weeks longer than the Puget Sound snails. In 1974, 31 females were collected at the tip of Bodega Head, Bodega Bay, California, and isolated for fecundity estimates. The highest capsule pro- duction by a single snail was 872. These capsules contained 6024 eggs. A second snail produced 842 capsules con- taining 6807 eggs. The maximum length of a single spawning period for this group of snails was 2 weeks. It appears, then, that California Littorina scutulata (Type II) produce fewer eggs and capsules while invest- ing more eggs in each capsule than do Puget Sound snails. THE VELIGER Page 471 With the data presently available, it is not possible to determine the source of differences in production. They may relate to population differences or to previous spawn- ing history. DEVELOPMENT ann HATCHING In Littorina scutulata, Types I and II, the early develop- ment is synchronous (Table 2) ; the blastula forms in 24 hours, and the gastrula within 48 hours - 24 hours slower than in L. planaxis. The trochophore is reached in 4 days and from this point until hatching, development is asynchronous. In L. scutulata, Type I, the trochophore lasts for 24 hours before developing into a shelled veliger stage by day 5. In L. scutulata, Type II, the trochophore stage lasts 48 hours before developing into a shelled veliger on day 6. In both types, the veliger remains in the egg capsule for 2 days, emerging on day 7 in Type I and on day 8 in Type II. The developmental sequences of L. planaxis and the 2 L. scutulata are contrasted in Table 2. Table 2 Summary of developmental events occurring within the egg capsule of California Littorina maintained at 15°C. Littorina Littorina Littorina scutulata scutulata Day planaxis “Type I” “Type II” 1 spawning spawning spawning 2 gastrula blastula blastula 3 trochophore gastrula gastrula 4 trochophore trochophore trochophore 5 veliger veliger trochophore 6 hatching veliger veliger 7 hatching veliger 8 hatching Hatching in Littorina scutulata s. I. is similar to that of Lacuna pallidula (da Costa, 1778) and L. saxatilis (= L. rudis) (Olivi, 1792) as reviewed by Davis (1968), in that the larvae emerge through a “hole.” It is doubtful, however, that the “holes” are homologous to the hatching pores in L. scutulata s.l. Lacuna pallidula and Littorina saxatilis spend a proportionately longer developmental period in the egg mass, emerging as juveniles after rasping through their respective encasements with their radulae. Page 472 Littorina scutulata, in contrast, emerge as veligers at a predetermined site, the hatching pore. The pore is cent- rally located on one surface of the egg capsule and the larvae are incapable of emerging at any other point. This has been demonstrated by noting the fate of embryos in capsules with opposite disc surfaces lying against the bot- tom of the culture dish. In these capsules, the hatching pore, which is not visible prior to its completion, forms on the same surface, irrespective of orientation. Larvae in capsules whose hatching pore is adjacent to the bottom of the dish are unable to emerge although the pore is com- pletely open. The hatching pore in Type I Littorina scutulata is located on the capsule surface with the larger rim. It has a mean diameter of 250m and represents an opening through which 2 larvae could simultaneously emerge. In Type II L. scutulata, the pore is located on the capsule surface with the smaller diameter and has a mean diame- ter of 340um. This represents an opening through which 4 larvae could simultaneously emerge. Rupture of the egg membrane is the first step in hatching and is apparently accomplished through 4a change in osmotic pressure. In both Type I and Type II Littorina scutulata, the egg membrane swells noticeably. Buckianp-Nicks et al. (1973) reported a $ increase in egg membrane diameter prior to hatching. The egg mem- brane can swell as much as 7 to 9 times the initial volume before hatching. The veligers emerge from their egg mem- branes before the hatching pore is evident, and may be actively involved in the formation of this opening. Move- ment within the capsule is limited but some swimming occurs. Abrasion of the inner capsule wall by the shell, employment of the snail’s radula and release of lytic enzymes from the larvae or egg membrane fluid may con- tribute to the emergence process. It also seems probable THE VELIGER. Vol. 21; No. 4 that the capsule wall is qualitatively different in the vicin- ity of the hatching pore or the point of emergence would be more variable. The presence of such a predetermined hatching pore is widely scattered through the mesogastro- poda, having been previously reported in Bithynia (Hyd- robiidae), Lamellaria (Lamellariidae) and Trivia (Era- toidae) by Fretrer & GraHaM (1962); in Strombus (Strombidae) by D’Asaro (1965) and in Monoplex, Mayena and Cabestana (Cymatiidae) by Laxton (1969). It is not previously known from Littorinaceans. DISTRIBUTION or CAPSULE TYPES AND PENIS MORPHOLOGY The area of coastline over which spawning females were obtained is roughly equivalent to the central third of the range reported by OLproyp (1927) for Littorina scutulata. The type of capsule produced did not correlate with wave exposure or the nature of the substrate (rock, sand, muddy sand). Furthermore, females producing the 2 morpho- typic capsules were found to co-occur at 5 of the Cali- fornia stations. The ranges of these morphotypes differ, however. Type I capsules were found only as far north as Newport, Oregon, while Type II capsules were found over the entire study area. BuckLANp-Nicxs et al. (1973) did not record dimorphic capsules during their study at False Bay, Friday Harbor, Washington, nor were they present at the 2 stations reported here which bracket their study area. Based upon the absence of Type I capsules from Puget Sound to date, we may ascribe the capsule figured by Buckianp-Nicks et al. (op. cit.), here designated as Type II, to L. scutulata sensu stricto because the area studied by these authors is the type locality for this species (OLDROYD, op. cit.). Table 3 Summary of the reproductive biology of Littorina from California. Littorina scutulata Type I Type of capsule pelagic Egg capsule diameter (mm) 11 Egg membrane diameter () 116.5 Egg diameter (2) 95.7 Number eggs per capsule 4-4] Number of days to hatching (15°C.) 7 Status at hatching planktotrophic veliger Shell width at hatching (yz) 169 Littorina scutulata Littorina Type II planaxis pelagic pelagic 0.7-1.0 0.3-0.4 130.5 100 105 89 1-14 1 8 6 planktotrophic veliger planktotrophic veliger 155 137 Vol. 21; No. 4 A dimorphism in the penis of Littorina scutulata was also found (Figure 2). Considering only gross morpho- logical detail, the form shown in Figure 2A has a con- spicuous sperm groove running dorsally to a sub-terminal bulge. This form also possesses more hyaline granules than the second form and shows an area of canals with black pigmented borders where the penis inserts on the head. The penis in Figure 2B differs in the placement of the sperm groove, which runs laterally to the tip, and in possessing a large papilla on the dorso-lateral surface proximal to the curvature of the penis. No intermediate penis morphologies were observed. The penes depicted in Figure 2A and B are both found in populations producing a mixture of the 2 egg capsule types. However, in a population from Anacortes, Wash- ington (collected 13 May 1978 by Dr. A. J. Kohn) only the penis type shown in Figure 2A was found (15 males of 50 snails examined; sex ratio not significantly dif ferent from 2:1). The absence of dimorphic penes from Puget Sound Littorina scutulata therefore contributes additional evidence that populations in this area are monotypic. Following the reasoning used for assigning the identity of egg capsules, L. scutulata s.s. males are characterized by the penis morphology depicted in Figure 2A. The species heretofore considered to be L. scutulata is characterized by males possessing the penis type illustrated in Figure 2B and by females producing egg capsules like that shown in Figure 1A (Type I). CONCLUSIONS Based upon the differences in egg capsule morphology, developmental rates and penes between the 2 morpho- types of Littorina scutulata, it appears that L. scutulata is a complex of 2 species. Type II female snails are con- sidered to belong to L. scutulata sensu strico as are males with the penis morphology depicted in Figure 2A. The identity of L. scutulata Type 1, however, is uncertain. GouLp (1849) described 2 additional species of Littorina from the Pacific Northwest, L. plena from San Francisco and L. lepida from Vancouver Island. A preliminary com- parison of idiotypes of L. plena (MCZ 169298) and syn- types of L. lepida (MCZ 169222) indicates shell charac- ters within the range of variation seen among female L. scutulata of both Types I and II. Therefore, L. scutulata Type I may be one of 2 species previously described by Gould or an as yet undescribed species which can co-occur wih L. scutulata s. s. from at least Newport, Oregon south THE VELIGER Page 473 Figure 2 Littorina scutulata penis types. Scale is 1.0mm to San Diego, California. The co-occurrence, the tenden- cy towards variable shell characters and the lack of ad- ditional material precludes a complete delineation of spe- cies characteristics at present. However, it is reasonable to expect that differences in radulae also exist and that radular differences can be correlated with egg capsules produced by a female or with penes in males. The diffi- culty with shell characters arises from the diversity of habitats these species occupy and the well known influ- ence of habitat upon molluscan shell characters. It is Page 474 THE VELIGER Vol. 21; No. 4 hoped that once L. scutulata is recognized as a complex of 2 species, differences in shell morphology and geometry independent of habitat can be identified. Gould used several parameters in his descriptions that can be quanti- fied, including shell length, width, apical and basal angles, and aperture shape. It should be possible using multivariate statistics (e. g., principal components, dis- criminant function analysis, etc.) to separate habitat vari- ability from variation between the 2 species at present regarded as Littorina scutulata. ACKNOWLEDGMENTS Material for this study was kindly supplied by G. Ander- son, C. Bridges, E. Elliott, S. Obrebski, A. Stone, K. West and T. West, all of the Pacific Marine Station and Dr. A. J. Kohn of the University of Washington. Dr. Dwight Taylor of San Francisco State University and the Pacific Marine Station initially suggested this study and supplied scores of snails. For the use of facilities at the Pacific Marine Station, I wish to acknowledge Dr. J. A. Blake. To Dr. Victor Loosanoff, I offer thanks for his support and guid- ance. Type material was kindly loaned by Dr. K. J. Boss, MCZ, Harvard University. This manuscript benefitted greatly from comments by Drs. A. J. Kohn of the Uni- versity of Washington, C. S. Hickman of the University of California at Berkeley, D. M. Pratt, Graduate School of Oceanography, University of Rhode Island and an anony- mous reviewer. To my wife, Miriam, for her continued support and enthusiasm, I am always grateful. Literature Cited Assorr, Rosser Tuczzr 1954. _ Review of the Atlantic periwinkles, Nodilittorina, Echininus, and Tectarius. Proc. U. 8. Nat. Mus. 103 (9328): 449 - 464; figs. 55 - 57 Banpe, Kraus 1974. Studies on Littorinidae from the Atlantic. (2): 92-114; 5 plts.; 22 text figs. Borkowski, THomas V, & Maryuinn R. Borkowski 1969. The Littorina ziczac species complex. The Veliger 11 (4); 408 - 414; pit. 66; 4 text figs. (1 April 1969) Buckianp-Nicxs, J., Fu-Saianc Cua « S. BEHRENS 1973. | Oviposition and development of two intertidal snails, Littorina sitkana and Littorina scutulata. Can. Journ. Zool. 51 (8): 359 to 365; 23 text figs. (March 1973) D’Asaro, CHaruzs N. 1965. Organogenesis, development and metamorphosis in the queen conch, Strombus gigas, with notes on breeding habits. Bull, Mar. Sci. 15 (2): 359-416; 17 text figs. (23 July 1965) Davis, CHarites C 1968. | Mechanisms of hatching in aquatic invertebrate eggs. Oce- anogr. Mar. Biol. Ann. Rev. 6: 325-376; 19 text figs. Fretrer, Vera & ALasTair GRAHAM 1962. British Prosobranch Mollusks. i-xvit+755 pp., illust. Ray Soc., London Gouxp, Avoustus Appi1son 1849. In: Minutes of the Meeting of the Boston Society of Natural History Proc. Boston Soc. Nat. Hist. §: 78-85 Laxton, J. H. 1969. Reproduction in some New Zealand Cymatiidae (Gastropoda: Prosobranchia). Zool. Journ. Linn. Soc. 48: 937-253; @ pits; 7 text figs. Oxpaoyp, Ipa SHEPARD 1927. The Marine Shells of the West Coast of North America. Stanford Univ. Press, Stanford, Calif. 2 (3): 1-399; [605 - 941] pits. 79 - 108 Rosewater, JosErH 1970. The family Littorinidae in the Indo-Pacific. Part I. The sub- family Littorininae. Indo-Pacif. Moll. @ (11): 417-§06; ples. 325 - 387 (go November 1970) STRUHSAKER, JEANNETTE WHIPPLE 1968. Selection mechanisms associated with intraspecific shell varia- tion in Littorina picte (Prosobranchia: Mesogastropoda) Evol. 22 (3): 459-480; 7 tables; 12 text figs. (September 1968) WHIPPLE, JEANNETTE A. 1965. Systematics of the Hawaiian Littorina Férussac (Mollusca : Gastropoda). The Veliger 7 (3): 155 - 166; plts. 25, 26; 4 text figs. (1 January 1965) The Veliger 17 (1 October 1974) Vol. 21; No. 4 THE VELIGER Page 475 The Epibiota of Arca zebra and Arca imbricata: A Community Analysis THOMAS B. SCANLAND (4 Text figures) INTRODUCTION MARINE QUANTITATIVE, BENTHIC community analyses, as such, had their beginning with PETERSEN (1911 et seq.). A level-bottom community concept was developed by TuHorson (1951 et seq.), who dealt principally with the infauna. The level-bottom community concept was expand- ed to include solid substrate habitats by NEWELL et al. (1959), who describe a rock-pavement habitat on the Bahama Bank. Most marine, hard-bottom community analyses have been restricted to intertidal and nearshore environments (under strong influence of shoreline conditions). Of off- shore community analyses, most have been qualitative in nature, and are generally lacking in the use of a consistent sampling unit. The use of a mollusk shell as a sample unit (as exemplified by WELLS, 1961, for an oyster com- munity; and by WE ts é¢ al., 1964, for an offshore scallop community) provides a standard to which other standardized-unit community analyses can be readily compared, and renders the study more easily repeatable. This paper describes such a study in the northeastern Gulf of Mexico. Literature on benthic communities in the Gulf of Mexi- co include Tass & MANNING (1961); DracovicH & KELLY (1964) ; HEDGPETH (1953); PARKER (e. g., 1960) ; Par- KER & Curray (1968) ; PEQUEGNAT & PEQUEGNAT (1968) and Warrten et al. (1950). Two extensive series of offshore collections were made by the “Blake” and the “Oregon,” the latter of which included several soft-bottom stations between Tampa and Cape San Blas. SUSIO (1973) has reviewed the literature on the eastern Gulf prior to the recent (1974-1978) Bureau of Land Manage- ment sponsored offshore environmental surveys. While the availability of proper substrate limits the extent of offshore epifaunal communities, such substrate is offered in this study area by the limestone banks which Lyncu (1954) cites as one of the unusual features of the Gulf. This bank is located 4.8km S of Dog Island, Franklin County, Florida (29°46’N; 84°32’W), in 10m of water. Similar limestone banks occur off Texas (Par- KER, 1960) and the Bahamas (NEWELL et al., 1959). Newell and his colleagues found the epifauna to be re- stricted by a covering of coarse, unstable sediments which are characteristic of these bank areas. The rock-pavement habitat provides attachment only for those organisms which can withstand the abrasion of, and avoid being buried by, these sediments. In the area of Dog Island this niche is filled predomi- nantly by 2 attached clams, Arca imbricata Bruguiére, 1792 (= A. umbonata Lamarck, 1819) and A. zebra Swainson, 1833 (Pelecypoda; Arcidae). A greatly varied epifaunal community, as expected for this latitude, is found upon these arks. This paper is an analysis of that community. METHODS ann MATERIALS Approximately 140 arks, 30 to 100mm in hinge length, were collected by hand for quantitative analysis, with the use of SCUBA in a relatively restricted part of the study area in June, September, and November, 1965. Another 110 arks for additional qualitative analyses were collected in 4 subsequent dives from December, 1965 to June, 1966. All were subjected to detailed examination under a dis- secting microscope. First the valves were separated, and the soft-bodied species of epifauna (e. g., polychaetes) were removed from each shell. These were counted, la- belled and preserved for later confirmation of tentative identification. The shells were numbered and dried, and a numerical quantification and analysis of area occupied on each shell by each of several groups of organisms (e. g., barnacles, ectoprocts, and serpulid polychaetes; see Table 2) was carried out for the initial 140 samples. All epifaunal species were identified to lowest possible taxon. In addition, the distributions of encrusting algae as a Page 476 group, and of the encrusting sponge Prosuberites micro- sclerus were noted on an outline sketch for each ark shell. The shells were then measured for length (measured along the hinge), height (measured vertically from above the point of the umbo to the ventral margin of the shell), and thickness (measured as the greatest distance between right and left valves below the point of the umbo). The sediment was analyzed by the method outlined by Emery (1937). Water temperature, salinity, and visibil- ity were also noted. All statistical tests used are outlined by Witcoxon & Witcox (1964). Frequency as used herein is the number of shells pos- sessing a particular encrusting group divided by the total sample size (140). Density is the total number of individu- als divided by the total sample size, and is given only for those groups which exist as solitary units (2.¢., are not colonial). The area occupied was obtained by estimating area covered by a particular encrusting group relative to the total area of the shell. These relative areas were then totaled and divided by the total sample size. The coverage of those species which rise above the surface of the ark was estimated by projecting their basal area onto the shell. The encrusting species which overlap, producing a strati- fied encrustation, were added separately. Consequently, in tabulations of the “area occupied” the total encrusted could exceed 100%, and the “area occupied” plus the “area unoccupied” commonly exceeded 100%. RESULTS PHYSICAL SETTING The bottom salinity varied from 32.6 to 38.0%. The temperature on the bottom ranged from 15.1°C in De- cember to 24.0°C in June. Over 7 dives when these meas- urements were made the visibility on the bottom averaged 3m and had a range of 1 to 7m. The sediment over the limestone is predominantly of sand-sized particles (as used by KRUMBEIN & PETTIJOHN, 1938). A breakdown of this sediment is given in Figure 1. The coarse fraction was principally of biological origin, the largest part mollusk shells and shell fragments. Other recognizable portions were contributed by corals, ecto- procts, crab and barnacle shells, and fragments from sand dollars and sea urchins. The depth of the sediment varied from 0 - 15cm over the limestone bottom. The bottom was, for the most part, flat with occasional elevations of 5-8cm. On 2 dives (June, 1965 and June, 1966) clumps of Ostrea equestris were seen which formed heads up to 4m in height. De- THE VELIGER Frequency (%) Vol. 21; No. 4 PI I 0.5 0.25 0.125 Particle size in mm Figure 1 Histogram of Surface Sediment pressions in the limestone not filled. with sediment were rare, but were up to 15cm deep. BIOLOGICAL DESCRIPTION In the macro-community the 2 most abundant fish spe- cies observed were a sea bass (Centropristis sp.) and the sand perch (Diplectrum formosum). Stomach analyses of specimens of both these fish obtained from the study area yielded organisms which were also found on the arks. Since more than half of the observed area of the macro- communjty is shallow sediment, many organisms which are associated with coarse sand bottom occur here. Al- though these sand bottom species were not included in this study, the most prevalent macroinvertebrates were the sea stars Astropecten sp. and Luidia sp., and the poly- chaete Chaetopterus variopedatus. Some of the smaller, motile invertebrates included in Table 1 may also be from the sandy substrate. Another faunal segment of the macro- community not included in the present study are the epi- faunal organisms which attach to the available solid sub- strate other than the arks. The most obvious species in this category were sponges including Axinella sp., Tethya sp., Cinachyra sp., and the gamma stage of Cliona sp. Of the 140 arks selected for intensive analysis, 49 were Arca imbricata and gi were A. zebra. Both of these ark Vol. 21; No. 4 THE VELIGER Page 477 Composition of the Epibiota from Arca zebra and Arca imbricata Taxonomic Group Porifera Axociella spinosa (Wilson, 1902) Cliona truitti Old, 1941 Cliona sp. Cyamon vickersi (Bowerbank, 1864) Leucetta floridana (Haeckel, 1872) Prosuberites microsclerus de Laubenfels, 1936, See Figure 3 Scypha barbadensis (Schuffner, 1877) Terpios fugax Duchassaing & Michelotti T. zeteki (de Laubenfels, 1936) Coelenterata Anthozoa Zoantheria zooanthids Actinaria Aiptasimorpha texaenis Calgren & Hedgpeth, 1952 Madreporaria Cladocora arbuscula (Le Sueur, 1820) Alcyonaria Anthopodium rubens Verrill, 1872 Platyhelminthes Turbellaria Polycladida Rhynchocoela Ascheliminthes Nematoda Ectoprocta Amathia sp. Antropora sp. Holoporella magnifica Osburn, 1914 Annelida Polychaeta Ceratonerets tridentata (Webster, 1879) Cirriformia sp. Crucigera websteri Benedict, 1887 Dodecaceria diceria Hartman, 1951 Dorvillea rubra (Grube, 1856) Eumida sanguinea (Oersted, 1843) Eunice filamentosa Grube, 1856 E. rubra Grube, 1856 Eupomatus sanctae crucis Kroyer, 1863 (See Hartman 1965, p. 574, 575) E. gairacensis Augener, 1934 Exogone dispar (Webster, 1879) Hydroides cf. crucigera H. microtis March, 1863 Remarks 15 other species including 1 lithistid 1 species 1 specimen 2 other specimens 1 other species This low red alcyonarian found on 2 shells in the Nov. collection 1 species 3 species Several species, these were found on most heavily encrusted shells, and particularly in detritus-filled barnacle tests and in the mud and mucous aggregations of errant polychaetes 12 other species This was the most frequently occurring species of errant poly- chaete; it was found most frequently in the tubes of serpulids and Sabellaria sp. The mucous tubes of this species were on 8 of the 21 Nov. arks and extended over most of the surface of each of these shells This was the most frequently occurring serpulid Page 478 THE VELIGER Vol. 21; No. 4 Table 1 (continued) Taxonomic Group Remarks H. norvegica Gunnerus, 1786 Hypsicomus torquatus (Grube, 1877) This was the most frequently occurring sabellid Lepidonotus sp. Loimia medusa (Savigny, 1818) Lumbrineris inflata Moore, 1911 This species occurred somewhat less frequently than Dorvillea rubra but was easily the second most abundant species; often occurred under ectoprocts, Ostrea sp., and Chama spp., and in the tests of barnacles Lysidice ninetta Audouin and Milne Edwards, 1833 Megalomma lobiferum (Ehlers, 1887) Neanthes succinea (Frey and Leuckart, 1847) Nereis sp. Polycirrus sp. Polydora ligni Webster, 1879 P. websteri Hartman, 1943 Polydora sp. Pomatoceros caeruleus (Schmarda, 1861) Pomatostegus stellatus (Abildgaard, 1789) Sabella melanostigma Schmarda, 1861 Sabellaria floridensis Hartman, 1944 Sabellastarte sp. Scalabregma sp. Terebella rubra (Verrill, 1873) (Homonym; Hartman, 1965; 527) Terebellides stroemi Sars, 1835 Tharyx sp. Trypanosyllis vittigera Ehlers, 1887 Vermiliopsis bermudensts (Bush, 1907) V. cf. occidentalis Spirorbids 2 species Flabelligerids 2 species 18 other species Sipunculida 5 species Mollusca Pelecypods Anadara transversa (Say, 1822) Anomia simplex Orbigny, 1845 Arca imbricata Bruguiere, 1789 1-30mm specimens of both these species were found in all three collections A. zebra (Swainson, 1833) Chama congregata Conrad, 1833 C. macerophylla Gmelin, 1791 This was the more abundant of the two Chama species Chione grus (Holmes, 1858) This species was the most abundant of the non-attached pelecypods Ischadium recurvum (Rafinesque, 1820) Modiolus americanus (Leach, 1815) Musculus lateralis (Say, 1822) Ostrea equestris Say, 1834 Rocellaria hians (Gmelin, 1791) A boring pelecypod, this species was found under a serpulid- ectoproct mass 3 other species Gastropoda Bulla occidentalis A. Adams, 1850 Calliostoma sp. Crepidula aculeata (Gmelin, 1791) This species was by far the more frequent of the two Crepidula species C. fornicata (Linné, 1767) Vol. 21; No. 4 THE VELIGER Page 479 Table 1 (continued) Taxonomic Group Remarks Diodora listeri Orbigny, 1853 Mistrella lunata (Say, 1826) This snail and O. seminuda were the most abundant non-sedentary gastropods Murex florifer Reeve, 1846 M. fulvescens Sowerby, 1834 M. pomum (Gmelin, 1791) Odostomia dianthophila Wells & Wells, 1961 O. seminuda (C. B. Adams, 1839) Vermicularia knorri Deshayes, 1843 This species occurred most frequently in the Nov. collection Arthropoda Pycnogonida Anoplodactylus lentus (Wilson, 1878) Crustacea Ostracoda 2 species Copepoda 3 species Cirripedia Balanus calidus Pilsbry, 1916 These two species comprised the bulk of the sessile barnacles B. venustus niveus (Darwin, 1854) Kochlorine floridana Wells and Tomlinson, 1966 2 other species Malacostraca Isopoda 1 species Amphipoda Ampelisca agassizi (Judd, 1896) Elasmopus rapax Costa, 1853 Lembos smithi (Holmes, 1905) Lysianopsis cf. alba Melita appendiculata (Say, 1818) This was the most frequently found amphipod Quadrivisio cf. lutet Rildardanus laminosa (Shoemaker, 1945) This species was found inhabiting the empty tubes of a serpulid and of Sabellaria floridensis; in the Sabellaria tube a male and a female were backed into the opposite open ends of the sand tube. Decapoda Mithrax forceps (Milne Edwards, 1875) M. pleuracanthus Stimpson, 1871 Pagurus impressus (Benedict, 1892) Pilumus sayi Rathbun, 1897 The most abundant decapod Stenorynchus seticornis (Herbst, 1788) 3 species of porcellanids Echinodermata Echinoidea Arbacia punctulata (Lamarck, 1816) Ophiuroidea 1 species Holothuroidea 1 species Chordata Urochordata Ascidiacea 3 species of solitary ascidians; 5 species of compound ascidians Algae Chlorophyceae Caulerpa sp. Rhodophyceae Botryocladia pyriformis (Borgesen, 1920) 6 species of encrusting algae; 2 other species of Rhodophyceae Page 480 THE VELIGER Vol. 21; No. 4 species attach to the substrate by means of a tough horny byssus which extends through the ventral gape of the paired valves. Thus an ark is aligned with its dorso-ventral axis perpendicular to the substrate and its broad hinge surface upward. Duc to the greater thickness to length ratio of A. imbricata (Figure 2) the upper hinge surface 55 50 nN On 40 Thickness in mm oo oOo 20 go 40 50 60 70 80 90 Length in mm e =Arca zebra, June A =Arca zebra, September © =Arca zebra, November @ =Arca imbricata, June @© =Arca imbricata, September @ =Arca imbricata, November Figure 2 Length vs. Thickness for 140 Arks in this species presents a larger surface area than in spe- cimens of A. zebra of identical length. Because of this _ apparent difference in surface area available for attaching organisms, Willcoxon’s rank sum tests were carried out between the 2 ark species to determine if the data from — the 2 could be combined. The tests were applied to 7 groups of frequently occurring encrusting organisms: acorn barnacles, boring barnacles, serpulids, Chama spp., Ostrea sp., encrusting algae, and encrusting ectoprocts. The data used for these tests came from the June and September collections which were tested separately (the November collection contained only 1 A. imbricata). Of the 14 tests, 12 showed no significant difference in the fouling of the 2 ark species at a= 0.05. The significant differences found were for different encrusting groups and from different collections (Ostrea sp. in June; serpulids in September). Because of the lack of test significance in the fouling characteristics of the 2 ark species, neither is considered to exert a preferential influence on the epi- fauna involved. Therefore, the data from the 2 ark species have been considered together in this analysis. In Table 1 is presented an annotated list of the 153 iden- tified taxa found on the 2 arks. Protozoans were excluded from this analysis and most of the microcrustacea were lost in the collecting process. As an illustration, in June, 1966, one large Arca zebra was collected by encircling it with a jar before wrenching the shell from the substrate. From this specimen, more amphipods in both variety and abundance were collected than for the 140 arks which were quantitatively analyzed, combined. Table 2 lists frequency, density and relative area oc- cupied for 18 groups of encrusting organisms. The densi- ty is omitted for colonial species, and the area occupied is omitted for boring barnacles. All the figures are given for total sample size (June: 62; September: 57; and Nov- ember: 21). Evidence of seasonal change was shown to be signifi- cant at a= 0.05 by the Wilcoxon rank sum test as fol- lows for 4 groups of encrusting organisms: increase in area occupied by compound ascidians from September to November; by Chama spp. in both September and No- vember over June; and by madreporarians in November over both September and June; and increase in frequency by Sabellaria sp. in September and November over June. Significant changes are indicated in Table 2. Although most of the encrusting organisms were con- centrated toward the middle of each valve, 2 consistent exceptions were noted. The encrusting sponge Prosuber- ites microsclerus was distributed in the posterior half of the shell, and predominantly along the upper posterior margin. In Figure 3, the locations of this sponge from 7 arks are superimposed on an outline sketch of an ark shell. The encrusting algae show a distributional pattern which is predominantly on or toward the dorsal surface. The ex- treme distributions of encrusting algae from 114 arks are shown in Figure 4. Since the boring barnacle Kochlorine floridana was frequently found in encrusting algae, the possibility of a correlation between the area occupied by encrusting algae and the density of boring barnacles was tested by a modi- Vol. 21; No. 4 THE VELIGER Page 481 Table 2 nacles, ectoprocts, Chama spp., Ostrea sp., madrepor- arians, serpulids, and the shell of the arks. The possibility of a correlation between shell length (which is an indication of age) and boring sponge pres- ence was also tested. A positive correlation at a= 0.05 Frequency (as %), Density, and Area (as %) Summary for 18 Groups of Sessile Organisms (N = 140) June Sept. Nov. indicates that arks tend to acquire boring sponge with age. ae A oe Fae nee : Maximum density figures often varied considerably eae 20 3.0 oy rom the mean per sample for encrusting species. There Boring Sponges No 19.4 19.3 38.1 y ae area 42 3.8 ig. cE sumbe Seer Barnacles ff 100.0 100.0 100.0 d. 22.9 14.4 13.1 area 5:8) Sul 4.2 Boring Barnacles f. 64.5 75.6 90.5 d. 18.2 13.5 52.8 Ectoprocts Nig 100.0 98.2 100.0 area 12.7 6.1 8.9 Encrusting Algae f. 72.6 91.2 95.2 area 8.3 8.4 9.2 Upright Algae f. 51.6 14.0 19.0 area 0.3 0.3 0.1 Compound f. 9.7 1.8 52.4 Ascidians area 0.4 0.1 2.3 Solitary fe 4.8 1.8 0.0 Ascidians area 0.2 0.0 0.0 Sabellaria sp. f. 72.6 98.2 100.0 d. 1.9 9.9 9.8 area Mea 2.9 4.0 Madreporians f. 38.7 54.4 95.2 surface Right area 1.0 0.6 4.4 Zooanthids f. 32.3 35.1 57.1 d. 6.5 6.9 19.2 area 0.6 0.7 WY Chama spp. f. 98.4 94.7 100.0 d. eS 5.8 12.6 omer area 2.5 6.8 8.7 umbo ae oe Ostrea sp. fe 100.0 100.0 95.2 d. 17.1 46.0 13°77 area 3.2 6.6 1.7 Arca sp. fe 45.2 38.6 95.2 d. 0.8 0.9 313 hinge area 0.6 0.3 2.8 surface Anomia sp. f. VET 10.5 14.3 d. 1.5 0.1 0.1 area 0.6 0.1 0.7 Crepidula spp. f. 19.4 1.8 52.4 d. 0.4 0.0 12 area 0.3 0.0 0.9 Serpulids f. 96.8 98.2 100.0 d. 29.1 30.1 34.1 area 7.4 2.9 3.9 Left fied Kendall rank correlation coefficient. The results of = that test were not significant at the a= 0.05 level. The Se aeee K. floridana was also found bored into encrusting bar- Distribution of the Sponge Prosuberites microsclerus on 7 Arks Page 482 inner umbo surface Right = ZLIOe L> x EEL ROLLER LLG hi PERO MBE POEL RRP surface /3SY LIL ‘ LQ DO yee Vip lateral surface Distribution of Encrusting Algae on 114 Arks were as many as 270 boring barnacles in a single ark and 7 other arks had densities greater than 100 per shell (over- all mean 28.1). The sessile barnacles had maxima of 149 and 143 per ark (X = 16.8). THE VELIGER Vol. 21; No. 4 Among mollusks, Chama spp. showed a maximum of 42, but only one other ark had more than 20 (x = 8.6). Four arks had more than 100 Ostrea sp., with the maxi- mum being 124 (X = 25.6). Most of these oysters were spat. The maximum occurrence of Arca spp. on one an- other was g, and the greatest density of Anomia sp. on any ark was 4. The Crepidula spp. had a similar low max- imum density with 5 occurring on one ark. Serpulids showed a density greater than 100 once with a maximum of 127. The next 2 high densities were 87 and 84 (X= 31.1). Sabellaria sp. showed a high of 70 in September, and 7 more shells from the September and November collections had densities over 20. The maxima for the Junecollection were 11 and 7 (overall mean= 7.2). DISCUSSION A highly varied epifaunal community occurs on Arca imbricata and A. zebra in the described offshore habitat. During the period of observation the arks were the most abundant macroinvertebrates present and characterized this habitat. Their contribution to the community in the area observed as an unburied substrate for the epifauna exceeded that of any other species. For the macro-com- munity there appear to be no other co-dominants. Within the epifauna associated with these arks, the dominant members are sessile and sedentary filter and deposit feeders. These dominants are at or near 100% frequency, have relatively high densities, and occupy a rel- atively large area of the ark shells in all 3 collections analyzed. They are barnacles, ectoprocts, serpulids, Cha- ma spp., and Ostrea sp. The area occupied by the oysters is less than that of the other 4, but its density is greater. The boring barnacles, because of their high density, and the encrusting algae, because of their high per cent of area occupied, are considered sub-dominants. All of these organisms except the algae rely largely on plankton and detritus for nutrition. The upright algae are a minor part of the community, and this leaves only the encrusting algae as significant primary producers. Since they are not available to the filter feeders, the community is not self-sustaining, but must depend on productivity from outside the community to maintain it. The most common errant members of the epifauna are 2 polychaetes, Dorvillea rubra and Lumbrineris inflata. Most of the polychaetes are filter or deposit feeders (in- cluding the cirratulids, flabelligerids, sabellariids, sabel- lids, serpulids, spionids, and terebellids). Other filter feed- ing members of this community not mentioned above ‘n- clude the remaining pelecypods and Crepidula spp., Ver- micularia sp., ascidians and sponges. Vol. 21; No. 4 With the exception of Dorvillea rubra, there are no frequently occurring carnivores resident upon the arks. Such carnivores as some of the fish, crustaceans, and gastropods, appear to move through the community, be- ing only temporarily present near any given shell. This distribution of producers and consumers leads to a trophic structure which, within the community, is highly imbalanced. Instead of the usual pyramid-shaped com- munity trophic structure representation (Opum « Opum, 1959), a diagram of this community would be diamond shaped, with the central bulge representing the predom- inance of lower level consumers, and the narrow bottom and top representing the scarcity of available primary producers and the expectedly low number of resident higher level consumers. The epifauna does not utilize the entire surface of the ark shell, but occupies the mid-portion of each valve. The anterior, posterior, and particularly the ventral margins generally have a thick periostracum which apparently discourages extensive encrustation. This thick periostra- cum is, however, used by errant polychaetes for shelter. Approximately 50% of the shell surface is generally unused, a large part of this being on the dorsal surface. Although the encrusting algae are preferentially located in this position, few other organisms are. The general lack of organisms attached on this hinge surface can be largely attributed to the flexion of the valves. Rigid organisms which do occur on the dorsal surface cannot extend across the hinge. The vertical aggregations occuring on the umbo and the middle of the valves on many specimens also in- dicate that there is some disadvantage to settling on the margins of the valves. These vertical assemblages, up to 4cm high, are both of one type of encrusting organism (particularly in barnacles, Chama spp., serpulids, or oys- ters) and composites of several types (particularly a barnacle-ectoproct-serpulid mass). Though no arks of less than 30mm in length were included in the quantitative study, many such small spe- cimens were collected during the course of this study as epifauna on larger arks. The encrusting organisms which are first to settle on these small arks are mainly those which can attach to the periostracum, as only the dorsal surface of the umbo and the hinge area are bare. These early setling organisms are barnacles, ectoprocts, serpulids, Chama spp., Ostrea sp., and Sabellaria sp. As these fouling organisms grow, the periostracum is ap- parently weakened and pulled off the ark. Simultaneously the ark is producing new periostracum at the periphery resulting in a generally bare central and umbonal area on each valve which may then be further settled. The only consistent further development with age (based on hinge length), not associated with season, is THE VELIGER Page 483 the acquisition of boring sponge. This development is at least partly due to the removal of the periostracum as those larger arks which were sparsely settled and whose periostracum covered most of the shell were in no instance infested with boring sponge. There was also an indica- tion that the acquisition of boring sponge was aided by infections by other borers, such as pelecypods, Kochlorine floridana, cirratulids, spionids and sipunculids. Seasonal changes were significant for compound asci- dians, madreporarians, Sabellaria sp., and Chama spp. The observed increase in frequency and density of Sabel- laria sp. in September suggests that some of these tube worms had settled since June. The evidence of summer reproductive activity is corroborated by the observation of spawning by 4 Sabellaria floridensis from the June collec- tion during the examination of ark shells in seawater. Compound ascidians increased in frequency and area occupied in November. Although the total area occupied divided by the total sample size is relatively small (2.8%), this result is partially due to the low frequency. A few of the arks in the November collection were covered to the extent that nothing showed of the ark but an opening corresponding to the gape between the valves which was being fused over by the meeting edges of the ascidian. This assumed dominance in a few instances by compound ascidians has been previously observed (WELLS ef al., 1964). The 2 groups of coelenterates studied quantitatively, the zooanthids and the corals, showed a similar winter increase. Though the apparent winter density for zoo- anthids of nearly 20 individuals per shell seems moderate- ly high, the extreme high densities for the November col- lections were 118 and 121, and the average per shell possessing any zooanthids was nearly 34. The phenomenon of dominance in a restricted part of each sample can be partly ascribed to the colonial nature of these forms. Where one individual or a small colony finds favorable conditions, quick development and expan- sion of the colony is possible. Relative increase of such forms in cold water may be due to their increased effi- ciency or the death or decreased efficiency of their warm season competitors, or both. In the case of compound ascidians, as in sponges, this patchy dominance is aided by a relative immunity to overgrowth by other organisms, allowing them, once settled, to avoid the problem of crowding and await favorable conditions for growth. The distribution of encrusting algae along the dorsal surface and only rarely down the sides beyond the middle of the valve seems to be related to the availability of light. The distribution of the sponge Prosuberites micro- sclerus is more difficult to account for. Although there may be some benefit gained by currents produced at the Page 484 posterior end by the incurrent and excurrent canals of the ark, the shape of the ark shell is probably more im- portant. There is a pronounced indentation extending from the umbo ventrally and posteriorly to the mid-pos- terior margin. The ribs are also strongly pronounced in this area in both species of ark. These 2 features may aid the sponge in becoming attached and remaining in the presence of strong abrasion. Most other portions of the shell are either covered by periostracum or are nearly smooth. Evidence of growth in area occupied with a concurrent decrease in density is shown for Chama spp. These chan- ges appear to be the result of rapid growth by the indi- viduals which escape the mortality factors responsible for the decrease in population size. There was apparently settling by Chama spp. after September. This is not only evidenced by increased density in November, following the September density decrease, but also by the large number of less than 1mm Chama individuals found in the winter collection. Ostrea equestris and both species of Arca also gave evidence in the form of small individuals (ca. 1mm) that settling had occurred between September and November. Of the communities to which this community m the northeastern Gulf of Mexico can be reasonably com- pared, 4 are sufficiently detailed to allow profitable com- parisons. The rock-pavement habitat of the Bahama Bank described by NEwE Lt et al. (1959) bears comparison since it is a parallel habitat in a lower latitude. The most detailed of these 4 is the description of the calico scallop (Aequipecten gibbus) community by WELLS et al. (1964), which is amollusk-centered, standardized-unit community analysis, and is, therefore, similar in treatment. It is a parallel community from a higher latitude, and is from a comparable habitat. Two others by PEQUEGNAT & PEQuEGNAT (1968) and by ALLEN (1953) make distance from shore and temperature inferences possible. Newell et al. record only about 26 species of inverte- brates, but they deal only with the more obvious forms (e.g., they list no polychaetes or crustaceans). The only pelecypod they mention is Chama congregata which also occurs in this community and which ranges from North Carolina to Florida and the West Indies. The Arca species are conspicuous by their absence, since the range of both species dealt with herein includes the Bahamas. The rock-pavement habitat in the Bahamas is dominated by gorgonaceans in the family Plexauridae which, Newell and his associates point out, are able to withstand the ab- __ rasion of the sand, as can the arks in the habitat off Dog Island. Neither the plexaurids nor any of the remaining species they list were observed in the study area and most are associated with tropical seas. THE VELIGER Vol. 21; No. 4 The species list provided by Wells et al. for the scallop epifauna includes 112 taxa. The scallop epifaunal com- munity closely resembles that of the arks. Of the domi- nants they list, Balanus venustus niveus, B. calidus, Poma- toceros caeruleus, and Sabellaria floridensis, all are pres- ent in the community off Dog Island. Pomatoceros caeru- leus occurs second in frequency to Eupomatus floridanus in the Arca epifauna; the Sabellana approach dominance off Dog Island only in the winter. The collection of scal- lops in North Carolina was made in the first week of April. Both of the dominant barnacles in the scallop epi- fauna share a position of dominance on the arks as well. It is pointed out by WELLs ef al. (1964) that most of the species were of wide-spread distribution (35), or were distributed principally south of Beaufort, North Car- olina (55), and that the community was tropical and sub- tropical in the majority of its affinities. At least 26 spe- cies are common to both communities, including Arca zebra. An important difference is in the lesser degree of success of Ostrea equestris and Chama macerophylla at- tained on the scallops, which were collected at the north- ern extent of the range of those 2 species. There are 153 taxa recorded from the Arca epifauna as compared with 112 from the scallops. The greater variety could be ex- pected with the more southerly latitude of the Dog Island habitat. Other differences, such as the degree of impor- tance of corals in these 3 communities, show the Arca rock-pavement community to be definably different from, though near its northern counterpart, the Carolinian epi- faunal assemblage. Spatial distribution differences between the epifauna of the arks and the scallops seem largely due to their different modes of existence. The arks are attached to the substrate and neither valve is preferentially selected by the sessile species of the epifauna. Imbalanced distri- butions which do occur on the arks vary from one indi- vidual to the next as to which valve has the heavier settlement, and these differences are due, at least in part, to varying proximity and orientation to neighboring in- dividuals. The scallop (Aequipecten gibbus), on the other hand, had an average of 73% of its lower valve unfouled, while the upper valve had no free area. This disparity in fouling between valves is due to the scallop’s resting on the same valve the majority of the time. PEQUEGNAT & PEQUEGNAT (1968) report on a fouling study which was carried out concurrently with this re- search. Their work was carried out off Panama City, Flori- da, approximately 100km west of Dog Island, with Cape San Blas about midway between the 2 study areas. They collected their data from floats placed at 5, 17, and 4»km offshore, from depths of 4 to 44m, and to within 1 or 2m Vol. 21; No. 4 of the bottom. The floats were exposed for periods ranging from 2 weeks to I year. Due to the differences inherent between an established bottom epifaunal assemblage and a variety of succes- sional stages of a series of separate suspended assem- blages, comparisons between the 2 species lists do not make the 2 appear very similar. A minimum of 15% of the species found on the arks are also found on the floats. However, a large number of the species listed from the floats are primary foulers, and very few of these species are present on the larger arks. For instance, 48 of the 187 taxa listed by Pequegnat & Pequegnat are hydroids, and none were found on the arks. Further, some of the species collected on the floats are associated only with that (7. e., suspended or floating substrates) habitat, such as some of the hydroids and the 3 species of stalked barnacles they list. The similarities between the epifauna on the arks and the 3 Pequegnat stations decreased slightly with their increasing distance from shore; 18% (17 of 92), 16% (22 of 132), and 15% (18 of 114) species in common at the 5, 14, and 40km stations,respectively. Despite these differences, the same groups were impor- tant foulers in both investigations, namely the barnacles, ectoprocts, and serpulids. In the case of the barnacles, the 2 most important species, Balanus calidus and B. venustus niveus, were the same. The oyster Ostrea equestris was also an important member of both communities. Impor- tant genera from the Arca rock-pavement community missing from the floats include the arks, and Chama in the pelecypods, and Sabellaria in the polychaetes. The most abundant serpulid in the epifauna of the arks, Eupomatus floridanus, is a rare member of the fauna taken from the floats. ALLEN (1953) found a greatly restricted epifauna (14 species) on Chlamys septemradiata in Scotland. His samples were from colder, deeper water, and on a finer substrate (mud) than in this study, all 3 of these factors pee to restrict the diversity of the epifauna (THorson, 1957). ACKNOWLEDGMENT The studies whose results are reported here were carried out as partial fulfillment for the requirements of The Florida State University, Tallahassee, for the degree of Master of Science. These studies could not have been successfully completed, and would not have been begun, without the encouragement, assistance and support of Dr. Harry W. Wells. THE VELIGER Page 485 Literature Cited Auten, Joun A. 1953. Observations of the epifauna of the deep water muds of the Clyde Sea area with special reference to Chlamys septemradiata (Mil- ler). Journ. Animal Ecol. 22: 240 - 260 DracovicH, ALEXANDER & JoHN A. KELLY 1964. Ecological observations of macroinvertebrates in Tampa Bay, Florida, 1961-62. Bull Mar. Sci. Gulf and Carib. 14 (1): 74-102 Emery, KennetH O. 1937. Rapid method of sand analysis. Abstract: 79 HepopetH, JozL WALKER 1953. An introduction to the zoogeography of the northwestern Gulf of Mexico with reference to the invertebrate fauna. Texas. Univ. Inst. Mar. Sci. Publ. § (1): 107-224 Krumpsgin, W. C. a F J. Petrijoun 1938. Manual of sedimentary petrography. Crofts, Inc., New York: 549 pp. Lyncg, S. A. 1954. Geology of the Gulf of Mexico. Mexico. Its origin, waters and marine life. Fishery Bull. 55: 67 - 86 Newe Lt, Norman D., J. Imprm, E. G. Purpy a D. L. THurBer 1959. Organism communities and bottom facies, Great Bahama Bank. Bull. Amer. Mus. Nat. Hist. 117 (4): 177-228 Opum, Eucenge Preasants e# H. T. Opum 1959. Fundamentals of ecology. W. B. Saunders Co. Philadelphia 546 pp. ParKER, Rosert HaLietr 1960. Ecology and distributional patterns of marine macro-inverte- brates, northern Gulf of Mexico. In: F PB Shepard e¢ al., Recent sediments, northwestern Gulf of Mexico, Publ. Amer. Assoc. Petrol Geol. Tulsa: go - 337; 6 plts.; 17 text figs. Parker, Rosert H. & JoszpH R. Curray 1956. | Fauna and bathymetry of banks on continental shelf, northwest Gulf of Mexico. Bull. Amer. Assoc. Petrol. Geol. 40 (10): 2428 to 2439 PeguzonaT, Wits E. « L. H. Pequronat 1968. Ecological aspects of marine fouling in the northeastern Gulf of Mexico. Texas A&M Univ. Dept. Oceanogr. Ref. no. 68-22T. 80 pp. Petersen, C. G. J. 1911. Valuation of the sea. I. Animal life of the sea-bottom, its food and quantity. Rprt. Dan. Biol. Sta. 20: 1 - 81 SUSIO [State University System Institute of Oceanography] 1973. | A summary of knowledge of the eastern Gulf of Mexico. Unpubl. Report Tass, Dursin C. e RaymMonp B. MANNING 1961. A checklist of the flora and fauna of northern Florida Bay and adjacent brackish waters of the Florida mainland collected during the period July, 1957, through September, 1960. Bull. Mar. Sci. Gulf and Caribb. 11 (4): 552-649 TuHorson, GUNNAR 1951. Animal communities of the level sea bottom. 27 (7): 481-489 WeLtts, Haary WILson a 1961. The fauna of oyster beds, with special reference to the salinity factor. Ecol. Monogr. 31: 239 - 266 Weis, Harry W, Mary Janz WELts e Irvine Emery Gray 1964. The calico scallop community in North Carolina. Sci. Gulf & Caribb. 14 (4): 561-593 Warrten, H. L., Hizpa F Rosene & Jozt WALKER HepopsTH & 1950. The invertebrate fauna of Texas coast jetties; a preliminary survey. Texas Univ. Inst. Mar. Sci. Publ. 1 (2): 55-88 Wricoxon, F « R. A. Wircox 1964. Some rapid approximate statistical procedures. Lab., Pearl River, New York: 60 pp. Proc. Geol. Soc. Amer. Appleton-Century- In: B S. Galtsoffi: Gulf of U.S. Fish & Wildlife Serv. Ann. Biol. Bull. Mar. Lederle KS Page 486 THE VELIGER Vol. 21; No. 4 Viability of Sperm in Two Land Snails, Achatina fulica Bowdich and Macrochlamys indica Godwin-Austen BY S. K. RAUT' ann K. C. GHOSE Department of Zoology, Calcutta University, 35, B. C. Road, Calcutta - 700 019, India INTRODUCTION ONE OF THE MOST IMPORTANT aspects of the reproduction and maintenance of a population level in terrestrial snails is the viability of sperms. The sperms received in copula- tion are stored temporarily in the storage organ of the snails. Information on the survival of sperms in the storage organ has been reported for only a few land snail species, viz.: Helix aspersa (TayLor, 1900) and Limico- laria martensiana (Ow1ny, 1974). Among aquatic snails, Viviparus (ANKEL, 1925), Crepidula (Cor, 1942), Lym- naea (Carn, 1956) and Oncomelania (Rotu, 1960, cited in Hyman, 1967: 301) are on record. Nothing is known concerning this in Macrochlamys indica, but Achatina fulica kept in isolation has been reported to lay viable eggs up to 382 days (MrErrR Monr, 1949). A series of experiments (Raut, 1977) established that cross-fertiliza- tion is essential for laying eggs in both A. fulica and M. indica. A number of broods extending over a considerable period is obtained from a single specimen after one mating, though repeated mating is a common phenom- enon. MATERIALS ann METHODS ‘Twelve pairs of cage-reared snails each of Achatina fulica and Macrochlamys indica were selected immediately after their first mating since the attainment of sexual maturity. They were marked pairwise as A, A,, B, B, ... L, L,, for A. fulica and a,a,,b,b, ... 1,1, for M. indica. Forty-eight cages, each measuring 50 X50 X 50cm, were used for the study. The sides and roofs of the cages were covered with 1.0mm polythene net. All 48 cages were placed on soft, humus-rich soil in a shady place in the Present address: Zoological Survey of India, Mollusca Section, 8, Lindsay Street, Calcutta — 700016, INDIA Calcutta University campus, Ballygunge, Calcutta, ex- posed to natural light, temperature, humidity and rain- fall. Only 1 mated snail was placed in each cage on March 30, 1975. The snails were kept active throughout the year by spraying with water when required, and a regular food supply was maintained until January 29, 1977, the date of termination of the experiments. The viable period of sperms was calculated from the date of the last brood since mating. EXPERIMENTAL RESULTS Of the 24 Achatina fulica B,, D,, F, and L, did not lay eggs. A,, A;, E,, G,, G,, H, and L, laid their first brood on April 18, 1975, while the remaining 13 specimens laid eggs at different dates between the 26" and 61" day after mating. Most of the snails deposited 3 broods, while only 3 snails (A,, G, and H,) laid 5 broods. The last brood was laid by the snail K,, 341 days after mating. The snails were maintained in a similar environment for a further period of 6 months. Subsequently they were dissected and the spermatheca as well as the talon were examined but no viable sperms were present. The viable period ranges (N= 20) from 42 to 341 days with a mean, standard deviation and standard error of 149.2, 87.54 and 19.11 days, respectively. Out of 24 Macrochlamys indica, e,, g, and k, did not lay eggs. The first egg laying took place on April 8, 1975 by the snails b,, b., c, and k,, while others laid their first clutch between 12 and 39 days from the date of mating. The last clutch laid by the snails a, and |, was on July 19, 1976, 2. €., 476 days after copulation. Most of the snails laid 6 broods during the period. They were maintained for another 6 months and dissection of spermatheca did not reveal viable sperms. The period of sperm viability ranges (N = 21) from 63 to 476 days with a mean, stand- ard deviation and standard error of 279.35, 101.54 and 22.71 days, respectively. Vol. 21; No. 4 DISCUSSION In some pulmonates the spermatozoa are produced in the ovotestis throughout the year and the ovotestis duct re- mains packed with sperms. Fertilization is dependent on the oogenesis cycle (CHATTERJEE, 1970; FRETTER & PEAKE, 1975; RAuT, 1977). Wide variations in the viable periods of sperms both in aquatic and land snails have been reported by a number of workers. In general, the period is longer in land forms. In aquatic snails the sperms are active for at least 116 days in Lymnaea (Cain, 1956), 150 days in Viviparus (ANKEL, 1925), 365 days or more in Crepidula (Cok, 1942) and 540 days in Oncomelania (Rot, 1960, cited in Hyman, 1967: jor). In land snails, the period is 520 days in Limicolaria (Ow1ny, 1974) and 1460 days in Helix (Taytor, 1900). MEER Mour (1949) observed that Achatina fulica laid viable eggs as long as 382 days. It appears that the sperms were viable for about 366 to 367 days, since A. fulica required 16 to 17 days for the development of fertilized eggs. The gestation period and the time required for fertilization were observed to be 20 and 3 to 4 days, respectively (RAUT, 1977). From the limited information available on the viable period of sperms in prosobranchs, basommatophorans and pulmonates it appears that the period varies with species and within the species. The interspecific variation in sperm viability is probably a specific character, which is supported by the fact that in spite of living in the similar environment, the period differs considerably in Achatina and Macrochlamys. Intraspecifically such variation is presumably influenced by the habitat, since the viable period of sperms in A. fulica was at least 366 - 367 days in Sumatra (MEER Monr, 1949) and 42 - 341 (average 149.2) days in Calcutta. The long viable period of sperms in pestiferous snails and their ability to lay a number of broods after one mating make it possible for them to populate a new area with the introduction of a single gravid specimen, and this demands our constant vigilance to prevent further spread of agri-horticultural snail pests. SUMMARY 1. The maximum viable periods of sperms observed in Achatina fulica and Macrochlamys indica were 341 THE VELIGER Page 487 and 476 days, respectively. It ranges from 42 to 341 (149.2 + 87.54) days in A. fulica and 63 to 476 (279.35 + 101.54) days in M. indica. 2. The interspecific variation in sperm viability is prob- ably a specific character, whereas intraspecific varia- tion is presumably governed by the bio-physical fac- tors of the habitat. 3. The long viable period of sperms is an additional ad- vantage to the species in permitting it rapidly to populate a new area. ACKNOWLEDGMENT The authors wish to express their sincere thanks to the Indian Council of Agricultural Research for financial support. Literature Cited Anrgi, Wutr Exuo 1925. Zur Befruchtungsfrage bei Viviparus viviparus L. nebst Bemerk- ungen iiber die erste Reifungsteilung des Eies. Senckenbergiana 7: 37 - 54 Cain, G. L. 1956. Studies on cross-fertilization and self-fertilization in Lymnaea stagnalis oppressa Say. Biol. Bull. 111: 45-52 Cuatrerjezez, B. 1970. Studies on the reproductive system in some Indian gastropods. Ph. D. Thesis, Calcutta Univ., Calcutta Coz, Wes.tey Roswetu 1942. The reproductive organs of the prosobranch mollusk, Crepidula onyx and their transformation during the change from male to female phase. Journ. Morphol. 70: 501 - 512 FRETTER, VERA & J. PEAKE 1975. Pulmonates. vol. 1: xxxviiit417 pp.; Acad. Press, London Hyman, Lissm HEnrieTTA 1967. The Invertebrates. 6, Mollusca 1: vii+792 pp.; illust. McGraw- Hill Book Co., N. Y., St. Louis, London Meap, AtBzrT RayMOND 1961. The giant African snail: A problem in economic malacology. Xvii+257 pp. Univ. Chicago Press Mour, J. C. vAN DER MzER 1949. On the reproductive capacity of the African giant snail, Ache- tina fulica (Fér.) Treubia 20 (1): 1- 10 Ow1ny, A. M. 1974. Some aspects of the breeding biology of the equatorial land snail Limicoleria martensiana (Achatinidae : Pulmonata). Journ. Zool. London 172: 191 - 206 Raut, S. K. 1977. Ecology and ethology of Achatina (Lissachatina) fulica fulica Bowdich and Macrochlamys indica Godwin-Austen. Ph. D. Thesis, Calcutta Univ., Calcutta Taytor, Joun W. : 1900. Monograph of the Jand and fresh water Mollusca of the British Isles. 1. Structural and General. Leeds, Taylor Bros. 454 pp- Page 488 NOTES & NEWS Recognition of Cyclocardia ovata (Riabinina, 1952) in the Eastern Pacific BY EUGENE V. COAN Research Associate, Department of Geology California Academy of Sciences, Golden Gate Park San Francisco, CA(lifornia) 94118 THANKS TO THE courRTESY of Dr. Alexander I. Kafanov of the Institute of Marine Biology in Vladivostok, a better understanding of certain eastern Pacific members of the genus Cyclocardia is now possible. Dr. Kafanov has sent a number of specimens of living and fossil species of this genus from the northwestern Pacific and Siberia not previously represented in collections in this country, as well as a copy of RiaBININA (1952), evidently not previously available in U.S.A. libraries. All of this materi- al has been placed in the California Academy of Sciences. One significant discovery permitted by this material was that the eastern Pacific specimens I tentatively re- ferred to “Cyclocardia cf. rjabininae (Scarlato, 1955)” (CoAN, 1977: 379-380; fig. 10) is instead probably C. ovata (Riabinina, 1952). The California Academy of Sciences Type Collection now contains paratypes of C. rjabininae (CAS 60014). Shells of C. ovata differ from those of C. rjabininae in having higher, more central beaks and in having a more arched hinge with propor- tionately smaller teeth. Cyclocardia ovata was originally proposed as Venericardia (Cyclocardia) borealis ‘‘var.” ovata Riabinina, 1952. This is not a homonym of Cardita ovata C. B. Adams, 1845, which, according to DALu (1903: 706), is a venerid. The distribution of Cyclocardia ovata (Riabinina, 1952) is now known to include the north and south coasts of _ Chukotsk Peninsula, and south in the western Pacific to Sakhalin Island. In the eastern Pacific, the species occurs near the Pribilof Islands and from Amchitka Island east- ward to Kodiak Island. THE VELIGER Vol. 21; No. 4 Literature Cited Apams, Cuarres BAKER 1845. Specierum novarum conchyliorum, in Jamaica repertorium, synopsis, ... Boston Soc. Nat. Hist., Proc. 2: 1-17 (Jan. 1845) Coan, EvcEne Victor 1977. Preliminary review of the northwest American Carditidae. The Veliger 19 (4): 375 - 386; 4 plts. (1 April 1977) Daur, WiLt1AM HEALEY 1903. Synopsis of the Carditacea and of the American species. Proc. Acad. Nat. Sci. Philadelphia 54 (4): 696-719 (20 Jan. 1903) RuBinina, N. V. 1952. Carditacea Chukotskogo Moria i Beringova Proliva. [Carditacea of the Chukotsk Sea and Bering Strait-] Akad. Nauk, SSSR, M., Krainii Severo-Vostok SSSR 2 Izd.-vo: 279-285; 2 figs. ScarLaTo, Orest A. 1955: Phylum Mollusca: Class Bivalvia. In: E. N. Pavlovskii (ed.), “Atlas of the invertebrates of the far eastern seas of the U.S.S.R” Akad. Nauk Moscow, 243 pp.; 66 plts. [translated by the Smithsonian Institution, 1966; 464 pp.] On the Relevance of Small Gastropod Shells to Competing Hermit Crab Species BY DENIS WANG Department of Zoology, University of Rhode Island Kingston, Rhode Island 02881 AND DAVID A. JILLSON Department of Zoology, University of Vermont Burlington, Vermont 05405 STUDIES ON GASTROPOD SHELL utilization by adult hermit crabs have demonstrated that the choice of a shell can influence crab survivorship (REESE, 1962; VANCE, 1972b) and fecundity (BoLLay, 1964). The literature on hermit crab competition in shell-limited environments has focused attention on shell utilization patterns of adult crabs (Bot- LAY, op.cit.; HAZLETT, 1970; KELLOGG, 1971; CHILDRESS, 1972; VANCE, 1972a, 1972b; GRANT & ULMER, 1974; WANG, 1975; BacH et al., 1976; FOTHERINGHAM, 1976). While the optimal-sized shell may contribute to enhanced adult fecundity and survivorship, an additional factor Vol. 21; No. 4 may play a crucial role in the outcome of competition among hermit crab species: competition among juveniles for small shells. Consider 2 species of hermit crabs competing in a shell- limited environnicnt, where there are fewer small, empty snail shells than newly-metamorphosed crabs. Interspe- cific competition among juvenile hermit crabs for their first shell is expected to be intense. The most abundant species of juvenile crab will not necessarily be the most successful. Aggression, size, and ability to locate unin- habited shells could influence the relative success of each species. The availability of small shells acts to regulate the total number of juveniles of each species recruited into the adult populations. This model allows several pre- dictions: 1- Competing hermit crab species should evolve mech- anisms reducing the intense juvenile interspecific com- petition for small shells. Temporal resource partitioning is one such mechanism. Species breeding during different periods of the year could insure that all available small shells are occupied by juveniles of that species. REESE (1968) and SAMUELSON (1970) reported different peri- ods of peak reproductive activity for hermit crabs in Ha- waii and Norway, respectively. REESE (op. cit.) reasoned that competition for food among planktonic larvae was responsible for the observed periodicity, but competition for small shells is an equally viable hypothesis. 2. The period of larval development for a competing hermit crab species may be reduced as compared to a species which does not compete for shells. This would be a form of exploitative competition in which larvae sett- ling first obtain shells. 3. If tiny shells do not persist in the environment for a significant period of time, hermit crab species should be expected to regulate their reproductive activity to co- incide with maximum shell availability. 4. Selection for large larval size or greater aggressive- ness could enhance juvenile survivorship. Larger larval size would allow a species to select larger shells immedi- ately and avoid competition if the 2 species settle at the same time. A more aggressive animal may have greater success in shell fights. Competition among adult females for an optimum- sized shell may be relatively unimportant. We suggest THE VELIGER Page 489 that hermit crab competitive ability is not principally correlated with clutch size. The reduced clutch size of a female would not necessarily affect the probability of her offspring obtaining their first shell. The ability of juveniles to secure a shell may be the major determinant of the outcome of competition among hermit crab species in shell-limited environments. ACKNOWLEDGMENTS We are grateful to A. Davis and E. H. Jillson for dis- cussions of these ideas, and to J. S. Cobb and W. R. Ellington for comments on the manuscript. Literature Cited Bacu, C., B. Hazretr e D. RittscHor 1976. Effects of interspecific competition on fitness of the hermit crab Clibanarius tricolor. Ecology 57: 579 - 586 Botiay, MELopy 1964. Distribution and utilization of gastropod shells by the hermit crabs Pagurus samuelis, Pagurus granosimanus, and Pagurus hirsutius- culus at Pacific Grove, California. The Veliger 6 (Supplement) : 71-76; 6 text figs. (15 November 1964) Cumopress, J. R. 1972. Behavioral ecology and fitness theory in a tropical hermit crab. Ecology 53: 960 - 964 FoTHERINGHAM, Nick 1976. Population consequences of shell utilization by hermit craba. Ecology 57: 570 - 578 Grant, W. C., Jr. « R. M. U_mer 1974. Shell selection and aggressive behavior in two sympatric species of hermit crabs. Biol. Bull. 146: 92-43 Hazzertrt, B. A. 1970. Interspecific shell fighting in three sympatric species of hermit crabs in Hawaii. Pac. Sci. 24: 472 - 482 Kextoge, C. W. 1971. The role of gastropod shells in determining the patterns of distribution and abundance in hermit crabs. Ph. D. dissertation, Duke Univ. 230 pp. Rezsg, E. S. 1962. Shell selection behavior of hermit crabs. Anim. Behav. 10: 347 - 360 1968. Annual breeding seasons of three sympatric species of tropical intertidal hermit crabs, with a discussion of factors controlling breeding. Journ. exp. Mar. Biol. Ecol. 2: 308 - 318 Samugtson, T. J. 1970. The biology of six species of Anomura (Crustacea, Decapoda) from Raunefjorden, Western Norway. Sarsia 45: 25-52 Vancz, RicHarp R. 1972a. Competition and mechanisms of coexistence in three sympatric species of intertidal hermit crabs. Ecology 58: 1062 - 1074 1972b. The role of shell adequacy in behavioral interactions involving hermit crabs. Ecology 53: 1075 - 1083 Wangs, D. 1975. Agonistic and shell fighting behaviors among two sympatric species of hermit crabs (Anomura: Paguridae). M. S. thesis, Univ. Delaware, 100 pp. Page 490 Soviet Contributions to Malacology in 1977 BY KENNETH J. BOSS AND MORRIS K. JACOBSON Museum of Comparative Zoology, Harvard University Cambridge, Massachusetts 02138 INTRODUCTION ONCE AGAIN WE OFFER a translation and commentary on the recent Soviet literature in malacology which was mostly published in the year 1977 and abstracted in the Referativnyy Zhurnal. This annual contribution to the community of interested readers (see The Veliger 20 (4) : 390 - 398; 19 (4): 440, for last year’s listing and for references to earlier resumés, respectively) will hopefully continue to be useful. With few exceptions, we have fol- lowed the editors of the Referativnyy Zhurnal in their arrangement of categories- Since specialists can proceed directly to items of par- ticular interest in special taxonomic categories, we have constricted these introductory remarks to more general topics and to the citations of more or less important pa- pers in which new taxa, new revisions or little known areas are covered. The diversity of problems to which Soviet workers ad- dressed themselves in 1977 (and 1976 for a few items) is as great as ever, though there is a noticeable reduction in topics related to commercial utilization of molluscan spe- cies and their otherwise applied usefulness. Also, for ex- ample, few papers deal with mollusks as vectors in para- sitic diseases. Of greatest importance to non-Soviet students are several works which propose more or less far reaching changes in the higher ranks of molluscan taxonomy and systematics. Such are papers by Shileiko on Docoglossa, Chistikov on Scaphopoda, Starobogatov on marine pul- monates, Scarlato and Starobogatov on Polyplacophora— a complete revision with 1 new order and 2 new sub- orders—and Shileiko on the Pulmonata. The last is a very important paper which has been expanded else- where and which casts doubt on the prevailing urethra- centered classification of the Stylommatophora. Novelties of lower rank were not neglected. Such were introduced by Sirenko (Lepidopleurus), Izzatullaev (Val- THE VELIGER Vol. 21; No. 4 vata), Minichev (Cylichna—plus a new subgenus Cyc- linoides), Minichev (Pneumodermopsis), Lus (northern buccinids), and Moskalev (Cocculinidae with 6 new mono- typic genera). Zoogeographical data from previously unknown or little known regions are also provided: Pirogov (Volga Delta), Gundrizer and Ivanova (Tuva), Boev (Bash- kiria), Starobogatov and Budnimova (Chukotsk Penin- sula), Guseva (Irkutsk), Iogansen, Mukhitdinov (south central Siberia), Izzatullaev, Mukhitdinov (Tadjikistan), Dolgin eé al. (subarctic Siberia), Likharev, Damyanov et al. (Bulgaria), Guntya (Dniester), Akramovski (Ar- menia), Rodionov et al. (Seliger Lake), Cheremnov (Khahasia), and Reznik (Kuma River). Problems in molluscan evolution are treated by Barskov, Shimansky, Nesis (cephalopods), and Neifakh (Lymnaea stagnalis). Data on the evolution of the molluscan ner- vous system are provided by Minichev, and Starobogatov discusses the evolution of cephalopod tentacular appara- tus. Interesting biological data on Turtonia minuta and Hiatella arctica are discussed by Matveeva and Maksimo- vich, on the genus Spinula (Malletiidae) by Filatova, and on the hydrobiid Semisalsa dalmatica by Chukchin. The following list explains abbreviations and acronyms used in this résumé: AN - Akademiya nauk (Academy of Science) Biol. Morya — Biologiya Morya (Marine Biology) DVBPI - Trudy Biologo-Pochvennyi In-ta. Dal’nevostochnyi Nauch- nyi Tsentr, AN SSSR (Proceedings of the Soil Institute of the Far Eastern Scientific Center of the AN USSR), Vladivostok Dokl. Akad. Nauk SSSR (Reports from the Academy of Science of the USSSR) EEMB - Eksperim. Ekologiya mor. bezpozvonochnikh (Experi- mental study, ecology and morphology of invertebrates), Vladivostok ES — English summary IFML - Issled. fauny morei, Leningrad, Nauka (Studies of ma- rine fauna, Leningrad Science Press) MN - Mollyuski, ikh sistema, evolutsiya i rol’ v prirode. Nauka. (Mollusks, their systematics, evolution and significance in nature. Science Press), Leningrad SPZM - Sovrem. probl. zool. i soversh. metodiki yeye prepoda- vaniya v vuse i shkole, perm’ (Contemporary problems of zoology and the improvement of teaching in institu- tions and schools) TRO - Trudy Instituta Okeanologii. Akademiya Nauk SSSR. (Transactions of the Institute of Oceanology, Academy of Science, USSR) VINITI — Vsesoyuznyi Institut Nauchnoi i Tekhnicheskoi Infor- matsii (All Union Institute of Scientific and Technical Information), AN, SSSR VPS - Vopr. paleontol. i stratigr. (Problems of paleontology and stratigraphy), Azerbaidzhan Vol. 21; No. 4 ZOB_~ - Zhur. Obshch. Biol. (Journal of General Biology) ZZ — Zoologicheskii Zhurnal (Zoological Journal) We thank Mrs. Mary Jo Dent for her careful typing of the manuscript. GENERAL Axramovsry, N. N. 1976. The molluscan fauna of the Armenian Socialist Soviet Republic. Erevan, AN ArmSSSR, 287 pp.; illust. [In this popular text, 155 species are listed and described] Aut-Zapz, Ak. A. & S. A. ALIEV 1976. | On the problem of the biogeochemistry of Pontian mol- lusks. VPS, Vyp. I, pp. 50-56 [40 species of 12 genera were studied for contents of calcium, mag- nesium, manganese, iron, aluminum, silicon, titanium, copper, strontium, barium and nickel. Even insignificant environment changes promote the formation of various structural peculiarities in the shell] Bozr, V. G. 1975. On the freshwater molluscan fauna of Bashkiria. Uch. zapiski (educational notes), Bashkir Univ. Vyp. 76: 25 - 32 [25 gastropod species and 12 bivalve species, of which 5 were cited for the first time, were found in 7 regions of Bashkiria. 32 species were found in the Volga Basin and 28 in the Ural River Basin] Cueremnov, A. D. 1976. On the ecology of the freshwater mollusks of Khakasia. SPZM, pp. 33 - 34 [A list of the freshwater bivalves and gastropods of the left bank of the Yenisei River is accompanied by ecological notes] Dotan, V. N., B. G. Iocanzen, E. A. Novixov & Ya. I. STAROBO- GATOV 1976. The freshwater mollusks of subarctic Siberia. Biol. os- novy ryb. kh-va resp. Srednei Azii i Kazakhstana (Basic biology of the fishing industry in the republics of Central Asia and Kazakstan), Dushanbe, pp. 69 - 71 Gonrvya, E A. 1975. Some results of the studies of mollusks from the Dniester Basin. MN, Sb. 5, pp. 60- 62 [78 species of bivalves and gastropods in 36 genera and 15 families are noted] Gunorizer, A. N., M. A. Ivanovna « E. A. Novikov 1977. The freshwater mollusks of Tuva. Trudy NII biol. i biofiz. pri Tomsk Univ. 8: 60 - 63 [59 species and subspecies (6 prosobranchs, 21 pulmonates and the remaining bivalves) constitute this fauna which bears a mixed Pale- arctic appearance. 26 Palearctic, 20 East Siberian, 10 European- Siberian and 3 Siberian taxa characterized the Yenisei Basin in Tuva. Also some Holarctic, western Mongolian and Sino-Indian species are present. The fauna of Ubsanura and Kobdo was less intensely studied] Iva, L. B., L. A. NEVESSKAYA & N. P. PARAMONOVA 1975. Regulation of molluscan evolution in isolated and par- tially isolated-bodies of water in the Late Miocene and Early Pliocene of Eurasia. MN, Sb. 5, pp. 188 - 190 THE VELIGER Page 491 [Certain trends are noteworthy in such bodies of water: 1) a very small number of families is present in comparison to the relatively large number of families and genera which constitute the source fauna in nearby, open marine basins; 2) a great increase in the number of species and their populations, especially endemics; 3) the predominance of representatives of euryhaline marine families; 4) the presence of brackish water forms; 5) the subdivisions of trophic regimes and the narrowing of niches. (The subject expressedly relates to the radiation of cardiids in the Ponto-Caspian Basin during the late Tertiary) ] IoGanzeEN, B. G. & V. N. Dotcin 1976. The freshwater mollusks of northwestern Siberia and their qualitative development. Vopr. biol. i agronomii (Prob- lems in biology and agronomy), Tomsk, pp. 67 - 77 [65 gastropod and bivalve mollusks are known from the various reservoirs in this distinct biota] IocanzENn, B. G., E. A. Novixov « A. D. CHEREMNOV 1976. Freshwater mollusks of south central Siberia. Probl. eko- logiya, Tomsk, 4: 125 - 136 (ES) [In this survey, 38 species of gastropods and 43 species of bivalves were treated] IzaTuLiakv, Z. B. 1976. On the freshwater molluscan fauna of northern Tadjiki- stan. Biol. osnovy ryb. kh-va. resp. Srednei Azii i Kazakhstana (Basic biology of the fishing industry in the republics of Cent- ral Asia and Kazakstan), Dushanbe, pp. 83 - 84 IZZATULLAEV, Z. 1977. New and little known freshwater mollusks of Central Asia. ZZ 56 (6): 948-950 (ES) [Valuata (Cincinna) gafurovi is described as new from mountain lakes (Sulukty-Sai) in the East Pamirs of the Gorno-Badakhshans- kaya Autonomous Republic, Tadjikistan. Also Sphaerium corneum and Musculium creplini were found in the East Pamirs] KoxocHasHvitl, G. V. 1976. Materials for a dictionary of Russian-Georgian concho- logical terms. Tbilisi, 80 pp. Minicuev, Yu. S. 1975. The origin of the molluscan nervous apparatus. MN, Sb. 5, pp. 15 - 18 Pozpnyakova, L. A. 1976. On the possibility of complex estimates of the deter- mination of calcium and magnesium contents in molluscan shells in connection with paleo-temperature analysis. EEMB, PPp- 140 - 142 SapvEHova, I. A. 1976. Shell marking in the study of mollusks. EEMB, pp. 194-155 [A survey of modern methods with a list of mainly English language papers] VotosuHina, M. I. 1977. ‘Terrestrial mollusks from the upper quarter of the Central Priputya [Formation] of the basin of the Chugur River. Faunal and floral complexes in the cenozoic of the Pre-Black Sea. Kishinev, Shtiintsa, pp. 57 - 61 [This is the first account of the land and freshwater mollusks of the late Anthropogenetic of the region. An attempt is made to clarify the topographic-climatic conditions of ancient Moldavia] Page 492 Yaros.avtseva, L. M. 1976. A study of the adaptation to the freshening of water in several species of littoral and estuarine marine mollusks. EEMB pp. 189 - 190 ZoLoTAREv, V. N. 1976. Perspectives in the study of the growth rates and ages of mollusks. EEMB, pp. 81 - 84 [The oldest specimen of the Far Eastern mussel, Crenomytilus grayanus, was calculated to be 104 years. Other species of bivalves were listed from 22 to 61 years. Analysis of the chemical contents of the shell offers better results in determining age] POLYPLACOPHORA SmeEn«xo, B. I. 1977. The vertical distribution of the chiton genus Lepido- pleurus (Lepidopleuridae) and a new ultraabyssal species. ZZ 56 (7): 1107-1110 (ES) [Known from the Carboniferous, Lepidopleurus is the most ancient of Recent chiton genera. It is characterized by a series of archaic features such as the weak development of the articulamentum, absence of insertion plates, narrow apophoses, and narrow muscular bands around the shell. Present in all seas except those with low salinity, Lepidopleurus is found mainly in the boreal regions, from the shallow zone to great depths. Lepidozona vityazi is described from the Bugenvilsky Trench at 6920- 7657m and constitutes the most abyssal of known chitons] StarosocarTov, Ya. I. & B. I. Smenxko 1975. On the systematics of the Polyplacophora. MN, Sb. 5, Pp. 21 - 23 [The following classification is proposed: Subclass Paleoloricata with Order Chelodida, Suborder Chelodina (2 families) and Sub- order Septemchitonina (1 family) ; Subclass Neoloricata with Order Scanochitonida, new (1 family), Order Lepidopleurida, Suborder Lepidopleurina (3 families), Suborder Choriplacina, new (2 fami- lies), Order Chitonida, Suborder Tonicellina, new (6 families), Suborder Acanthochitonina (2 families) and Suborder Chitonina (4 families) ] GASTROPODA, GENERAL Damyanov, SERAFIM G. & ILyaA M. KoKHAREV 1975. The fauna of Bulgaria. 4. Land gastropods. Sofia, Bul- garian Acad. Sci., 425 pp.; illust. [Included are 214 species and subspecies: 4 species in 2 families of prosobranchs, 3 species of one family of basommatophoran pul- monates, and 24 families of stylommatophorans. A thorough and varied introduction discusses numerous phases of the biology, physio- logy and ecology of these mollusks] Minicuev, Yu. S. & Ya. I. StaroBoGATOV 1975. On the systematics of the Euthyneura. MN, Sb. 5, pp. 8-11 [Four groups exist in the Euthyneura: 1) the Siphonariidae, which are possibly not related to primitive hyperstrophic forms; 2) the Pulmonata; 3) the typical opisthobranchs; and 4) the aberrant THE VELIGER Vol. 21; No. 4 opisthobranchs. The latter 3 groups are phylogenetically related to primitive hyperstrophic forms. The independent origin of these 4 groups from primitive Diotocardia is demonstrated and it is sug- gested that each group should be regarded as a subclass] Nawenko, V. P. « T. Kz. Namenxo 1976. Thermal stimulation of spawning and cultivation of larvae of two species of gastropods in aquaria. EEMB, pp. 125 - 126 [ Tectonatica janthostoma and Aeolis sp. were induced to lay eggs; features of their reproductive biology are discussed] PETRUNYANKA, V. V. 1977. ‘The distribution of carotenoids and myoglobin in the tissues of pulmonates. Zh. evolyuts. biokhimii i fiziol. 13 (2) : 218 - 220 (ES) [Tissue extracts of Helix pomatie, Lymnaea stagnalis, and Planoy- barius corneus were studied spectrophotometrically] SHieiko, A. A. 1975. Peculiarities of the excretory system of the pulmonates in connection with their subclass classification. MN, Sb. 5, pp. 12-15 [The structure of the kidneys is at present used as the major taxobasis for the classification of the Pulmonata. It is demonstrated that the sigmurethrous condition, in one form or another, appears in all terrestrial pulmonates, even in the Orthurethra. However, in that group, the distal portion of the kidney displays a tendency to be shorter. The heterurethrous condition is the first result of shell reduction in all groups where this reduction takes place. For these reasons the taxonomic distinction of larger groups on the basis of the kidneys is not feasible] Smer, L. S. « L. I. PSHENICHNIKOVA 1976. Melanistic pigmentation of some freshwater and terres- trial gastropods and its significance. Vopr. biol. i agronomii (Problems in biology and agronomy), Tomsk, pp. 100-106 [In aquatic pulmonates, aquatic prosobranchs and land pulmonates the pigmentation is without taxonomic significance, but, in some cases, may serve a thermo-regulatory function] StarososaTov, YA. I. 1977- Class Gastropoda [in] Opredelitel’ presnovod. bespoz- vonochnykh Evrop. chasti SSSR (Handbook of freshwater in- vertebrates of the European portions of the USSR). Plankton and Benthos. Gidrometeoizdat, Leningrad, pp. 152-174 [58 species in 13 families of gastropods are considered; brief eco- logical notes, distributional data, and synonymies are provided] StaropocarTov, Ya. I. & L. L. BUDNIKOVA . 1976. On the freshwater gastropod fauna of the extreme north- eastern USSR. DVBPI 36 (139): 72-88 [In total, 20 species are considered, 15 from the Chukotsk Penin- sula; 4 species are common to America and the Chukotsk, 1 from northwestern America new to the USSR. 2 new species and 1 new subspecies are described] ; Yevoonin, L. A. & Yu. S. MiniIcHEV 1975. Adaptations of pelagic mollusks. MN, Sb. 5, pp. 24 - 26 [The basic adaptive change involved the organs of locomotion, and . alterations of other structures are correlated with it] Vol. 21; No. 4 PROSOBRANCHIA Cxuuxucui, V. D. 1976. The functional morphology of Semisalsa dalmatica, a gastropod new to the Black Sea. ZZ 55(11): 1627 - 1634 [Semisalsa dalmatica resembles the Hydrobiidae but differs in the morphology of its reproductive system. Unlike the hydrobiids, the pallial oviduct is a simple slit and does not have longitudinal folds separating it from the vaginal canal. The renal oviduct has 2 light [colored] loops and lacks the dark pigmented spiral of hydrobiids. A channel connects the oviduct with the mantle cavity. The male reproductive system also differs from that of the hydrobiids. Structurally, Semisalsa is a rissoid but not assignable to any known family. Although the female genital anatomy indicates a relation- ship with the Cingulopsidae, the male system differs decidedly. It is suggested that a separate family may have to be erected] Gatxin, Yu. I. 1976. The distribution of Trochidae in the Barents Sea with contemporary changes of climate. Donnaya fauna Kraev. mor- yei SSSR (Benthic fauna of the regional seas of the USSR), pp. 61 - 77 (ES) [Encompassing data from 1838-1973, there were changes in the Trochidae which corresponded with temperature variations. During the 1920’s and 1930's, a warming of water drove the arctic species northward and allowed an increase in boreal species. A reversal of this process occurred during the period of chilling in the 1960’s] Goncuarov, A. D. 1977. Rapane at the northwestern shore of the Black Sea. Gidrobiol. zh. 13 (3): 29 - 31 [Data are provided on the distribution, density, composition and distribution at various depths and substrates. A morphologically distinguishable form, Rapana thomasiana thomasiana odessanus, is established] Goryacuev, V. N. 1977. New data on the morphology and distribution of Nep- tunea laticosta Golikov (Gastropoda, Buccinidae). ZZ 56 (4) : 631 - 633 (ES) [The egg capsule and the structure of the distal portion of the penis are described. The species is cited for the first time from the Bering Sea in the presence of the subspecies, N. laticosta ochotensis] Karasen, O. Z. 1977. ‘The distribution of the species of Abeskunus in the cen- tral and southern Caspian. VINITI, Manuscript dept., No. 1959-77 [From 321 stations, more than 150000 specimens of Abeskunus Kolesnikov, a subgenus of Pseudamnicola, were taken. Geographi- cal, ecological, and bathymetrical data are provided for 3 species: A. brusinianus (Clessin & Dybowski) occurs from shallow depths to 210m in all the central and southern Caspian; A. sphaerion (Mous- son) is found mainly in the southern Caspian to depths of 50m; and A. depressispira (Logvinenko & Starobogatov) is stenotopic in the southern Caspian to 100 m] Karaseitt, O. Z. a B. M. LocvineENKo 1977. The distribution of the gastropods of the section of Trachycaspia of the genus Turviscaspia in the central and southern Caspian Sea VINITI, Manuscript dept., No. 559-77 THE VELIGER Page 493 [Three species of Trachycaspia are now known. The most widely distributed and abundant species, T: dimidiata Eichwald, is found mostly in the central part of the sea although a few occur to the south in the Apsherenki Rapids and occupy widely differing sub- strates, mainly between 10 - 250m. T. bakuana Kolesnikov, endemic in the southeastern Caspian, lives to 100m in substrates different from the other species. T: laticarinata Logvinenko Starobogatov. endemic in the southwestern Caspian to depths of 160m, has narrow ecological tolerances and a restricted geographic range. All these species have patchy distributions within their ranges, a situation possibly correlated with the absence of a swimming larva] KonpraTenkoy, A. P 1976. Potential tolerance to salinity in populations of Hydro- bia from the White Sea. EEMB, 87 - 89 [After acclimatization to an initial salinity of 20 parts per 1000, the euryhalinity of the mollusks increased an average of 4.5 times. The potential tolerance of various populations differs strongly and increases from the open sea toward estuaries] Lus, V. Ya 1976. New and rare deepsea buccinid species from the Kurilo- Kamchatka and Japanese Trenches. TRO gg: 71 - 84 (ES) [Buccinum lamelliferum is described as new from the Kuril-Kam- chatka Trench. Additional data on abyssal and bathyal species, B. diplodetum Dall, 1907 and B. kashimanum Okutani, 1964, are pro- vided. The shell, operculum, radula and anatomy of each species are discussed] Marveeva, T. A. 1977. The reproductive ecology of several species of gastro- pods in the upper shelf of the Sea of Japan Shelf (Pos’eta Bay). 1. S’ezd sov. okeanologov, vyp. 2, tezisy dokl., Moscow, “Nauka,” (First session of soviet oceanologists, 2. thesig re- ports), Pp. 24 - 25 [The following types of larval development were observed: 1) Pelagic a) the veliger develops frorn a free swimming trochophore: (Collisella radiata, C. herold:) ; b) the veliger develops in a planktonic egg capsule (Littorina brevicula, L. squalina, Tegula rustica) ; c) the veliger develops inside the deposited egg-case which is fastened to a firm substrate (Epheria turrita, Thapsiella pli- cosa, Tectonatica janthostoma, Boreotrophon candelabrum, Mitrella burchardi, Nucella heysiana, Tritia sp.) ; 2) Direct development - the veliger develops in the deposited egg which is fastened to the substrate (Littorina kurila, Falsi- cingula mundana, Euspira pila, Tritonalis japonica, Tritia acutidentata, Homalopoma sangarense) . Larvae appear in the plankton at the end of March at a water temperature of -o.7and a relative scarcity of phytoplankton. In May, the number of larvae increases considerably and reaches the maximum in June. In the following months the numbers decrease gradually and in October only isolated individuals are seen in the plankton. The settling of the larvae and the appearance of young in most species takes place from July to September. This later phase of reproduction is limited by rather narrow temperature limits (18 - 21°)] Mosxa ev, L. I. 1976. On the generic classification of the Cocculinidae (Gast- ropoda; Prosobranchia). TRO go: 59 - 70 (ES) Page 494 [6 new genera and their type-species are described: Fedikovella (F caymanensis), Teuthirostia (T. cancellata), Kurilabyssia (K. squamosa), Caymanabyssia (C. spina), Bandabyssia (B. costocon- centrica), and Tentaoculus (T. perlucida). 69 species and 2 genera previously described are listed] Paxuomoy, A. N. 1976. An analysis of deviation and regulation of the distribu- tion of isozymes in Littorina littorea during the adaptation to salinity fluctuations. EEMB, pp. 137 - 138 PoBEREZHNYI, E. S. & T. Ya. SrrnrKova 1976. A report on the number of chromosomes of the Lake Baical species Benedictia baicalensis Gerstf. (Gastropoda, Pro- sobranchia). Novy materialy po faunye i flore Baikala, Irkutsk, PP. 142-144 [2N = 34 with 17 bivalents at metaphase] Sureixo, A. A. 1977. The symmetry of the Docoglossa and the problem of the origin of the order. Byul. Mosk. O-va ispyt. prirody Otd. Biol. (Bulletin of the Moscow Naturalist’s Society, Biology Series) 81 (3): 60-65 (ES) [The representatives of the Docoglossa have neither a turbospiral form nor stage in their ontogenesis. The asymmetry of the mantle cavity is therefore not related to a former turbospiral stage but to the adaptation of the respiratory system to aquatic currents; these adaptations include the disappearance of the right ctenidium and the concomitant restructuring of internal organization. Thus, the symmetry of the Docoglossa is a primitive feature and the shell is initially exogastric. Earlier endogastric ancestors might well have been the Cambrian Helcionellidae] Smenxo, B. I. & V. L. Kas’yanov 1976. ‘The abalones of Monneron Island (Sea of Japan). Biol. Morya, No. 6, pp. 20 - 25 (ES) [The authors claim that the presence of Haliotis kamtschatkana in the seas of the USSR is based on erroneous 19" century labels. The northernmost Soviet population of Haliotis discus occurs on Monneron Island and some biological details of this population are provided] TstKHON-LUKANINA, E. A. 1976. ‘The feeding of the gastropod Gibbula divaricata in the littoral zone of the Black Sea. EEMB, pp. 186 - 188 [A study of the energy flow in colonies of G. divaricata which feed on periphyton and detritus] ViLEnEIN, B. Ya. « M. N. VitENKINA 1977- | Response of individuals of White Sea populations of Littorina obtusata and L. littorea to temperature changes. ZZ 56 (6): 829 - 834 (ES) [Individuals of the 2 species of snails were placed into artificially controlled temperature regimes and showed differences in prefer- ences. Homing was clearly observed in L. littorea but less so in L. obtusata, a phenomenon which apparently correlates with the pe- lagic larva of the former and the direct development from the egg of the latter. Being panmictic, L. littorea apparently is character- ized by a more greatly developed system of acclimatizations] THE VELIGER Vol. 21; No. 4 OPISTHOBRANCHIA Minicuey, Yu. S. 1976. On the morphology of the pelagic mollusks of the fami- ly Pneumodermatidae (Opisthobranchia, Gymnosomata) in Antarctic waters. IFML 18 (26): 102 - 106 (ES) [A discussion of the characteristics of the Pneumodermatidae is provided and Platybrachium antarcticum (a new genus and new species) and Pneumodermopsis brachialis (a new species) are de- scribed] 1977- On the morphology and systematics of the genus Cylichna (Gastropoda; Opisthobranchia) from Franz-Josef Land. IFML 14 (22): 428-434 (ES) [Cylichna occulta (Mighels), C. alba (Brown), and C. arctica (a new species) are described. A new subgenus Cylichnoides is erected on the basis of shell structure and reproductive morphology with C. occulta as type species. The subgenus possesses a different copula- tory apparatus and a lamellar larval shell. The peculiarities of heterostrophy are noted for several species] TERRESTRIAL PULMONATA Axramovskl, N. N. & G. S. Basayan 1976. Methods in controlling the mountain snail (Vitrinoides monticola armenica) against attacking hothouse tobacco in Armenia. Tekhekagir gyukhatntesakan gitutyunner, Izv. s.-kh. Nauk, No. 10, pp. 68-72 (Armenian with Russian summary) [The snail is nocturnal in its habits; chemicals and their applica- tions against these pests are discussed] BureENnKov, M. S. 1977. The growth structure of populations of 3 species of snails Stylommatophora, Pulmonata). ZOB 38 (2): 296-304 (ES) [Populations of Agriolimax reticulatus, A. laevis and Arion circum- strictus were studied in different biotopes; the number of genera- tions per annum is correlated with climate, being least in the most rigorous conditions and most in the more equitable] Doarrrteva, E. F « Ya. S. SHarmo 1976. Physiological and toxicological aspects in the postem- bryogenesis of the reticulated slug (Agriolimax reticulatus). Nauchnye trudy Leningrads. s.-kh. in-ta. 297: 91 - 94 GoroxruHov, V. V, A. A. SumeztKo « R. Ya. Buty.in 1975. On the terrestrial molluscan fauna as intermediate host of protostrongilids in southern Kirgizia. Tr. vses. in-ta helmintol (Transactions of the All Union Institute of Helminthology) 22: 43-51 (ES) [52 species are found in the pasturelands. 3 epidemiological situa- tions are recognized: 1) a dangerous zone in the spring, fall and winter pasturelands at 1000-2090 m above sea level where, basically, invading animals with protostrongilids originate; 2) a potentially dangerous zone in summer pasture lands at 2000-3000m where sheep with protostrongilids appear to a lesser degree; 3) on summer Vol. 21; No. 4 pasture land at 3ooom and higher where sheep infected with pro- tostrongilids do not appear] KuHoxkHuTKIN, I. M. 1976. Polymorphism as a method in determining populational areas of land mollusks. SPZM, pp. 153 - 154. [The polymorphic structure may serve as a criterion for the con- tinuity of distributional areas of a species] KaoxuHutin, I. M. « A. I. Lazareva 1975. Polymorphism in populations of some Caucasian land mollusks. Mn, Sb. 5, pp. 32 - 34 [The banding structure of populations of Fructicocampylaea nar- zanensis, Xeropicta krynickii, and Caucasotachea atrolabiata was studied. It was shown that, unlike dimorphic populations of Brady- baena, the polymorphism of the populations studied is phenotypic in nature] Lixnarevy, I. M. 1975. The zoogeographic characteristics of the land molluscan fauna of Bulgaria and its origin. MN, Sb. 5, pp. 26-29 [There are 9 zoogeographical groups: 1) widely distributed, boreal species (23) ; 2) general European species (34) ; 3) Euxine species (18) ; 4) Atlantic-Mediterranean species (7) ; 5) Southern Europe- an mountain species (10) ; 6) Central European mountain species (26) ; 7) endemic Balkan species and subspecies (50) ; 8) xerophilic species of Near-Eastern origin (16); and 9) xerophilic species of Mediterranean origin (13). In the fauna of the Balkan Province, almost half of the 550 species are endemic} Muxurroinovy, A. B. 1975. | Zoogeographical analysis of the land mollusks of North Tajikistan. MN, Sb. 5, pp. 29 - 31 [Of the 63 species (26 genera and 13 families), 3 zoogeographical groups can be recognized: 1) widely distributed boreal species (10) ; 2) Europo-Asiatic mountain species (7); 3) endemic northemn Asian species (41)] Nixo.aey, V. A. 1976. On the ecology and distribution of helicoids in the heights of central Russia. SPZM, pp. 109 - 111 {7 species of helicoids are known from there in the families Hydro- miidae and Helicidae. Short remarks on their distribution and ecology are included] Omarov, ZH. K. « A. FE. Ivan’Kova 1976. Double diffusion reaction in starch-gel immunochemical analysis of the polymorphic species Bradybaena plectotropis. KazSSR Fylum Akad. Khabalary, Izv. AN KazSSR, Ser. Biol. 4: 18-24 (Kazakh summary) [Antigenic studies confirm the large degree of polymorphism of B. plectotropis in comparison to B. lantzt] PaxHorukova, L. V. & P. V. MaTEKIN 1977. Interspecific distinctions in the influence of temperature on the duration of embryonic development in slugs. ZOB g8 (1): 116-122 (ES) [A comparison of geographically separate populations of Agnolimax agrestis and A. reticulatus showed decided differences in the in- fluence of temperature on the length of embryogenesis] Prosoyv, V. V. 1977. The terrestrial pulmonate fauna of the Volga Delta. ZZ 56 (8): 1248-1250 (ES) THE VELIGER Page 495 [7 species of stylommatophorans were taken, of which Succinea elegans (Risso), Pseudotrichia rubiginosa (A. Schmidt) and Zonito ides nitidus (Miller) were most numerous, sometimes occurring in densities of 2500/m?. Spring floods control the densities and effect dispersal] Reznik, Z. V. 1976. | Faunistic characteristics of land mollusks in the flood plain forests of the Kuma River. SPZM, pp. 131 - 133 [There is a decline in the number of species in forests along the Kuma from the border of Georgievska to the village of Vladimirov- ka] Sapiro, Ya. S. 1976. Harmful slugs. Zashchita rastenii (The Protection of Plants), No. 9, pp. 28 - 30 [Data on the external structure and the biology of the most common species in the USSR are provided] Suixov, E. V. 1976. On the dispersal of land mollusks during flood times. ZZ 56 (3): 361 - 367 (ES) [28 species of slugs and snails, constituting 57% of the malacofauna of the Kalinin region are transported by flood waters. The extent of this dissemination depends on the geomorphology of the terrain and on the nature of the animals] Soxotov, V. A. « V. A. KovaLev 1977. The electrical activity of the cerebral ganglia of Helix vulgaris during statocyst stimulation. Zh. evolyuts. biokhimi i fiziol. 13 (4): 512-513 (ES) [Testing was conducted at 30, 60, 150, 300, 500, and 1000 Hertz. Since at frequencies of 2000 and 5000 there was no response, the threshold frequencies were established at a low of go and a high of 1000. 3-4 stimulations at one frequency at intervals from 1-2 minutes brought about a reduction and finally a disappearance of a response. Transference to another frequency occasioned renewal of the response. The neuronal cells associated with the statocyst stimu- late a response in the cerebral ganglia] PULMONATA, AQUATIC Arutyunova, L. D. . 1977. Aphallia in a population of Radix (Gastropoda, Lym- naeidae) from Armenia. Biol. Zhur. Armenii 30 (3): 89-90 (Armenian summary) [50% of a population of Radix auriculana in the plain of Ararat was found to be aphallic. The mollusks were not infected, and the condition was not due to parasitical castration] Guseva, M. I. 1976. On the general problem of the pasture malacofauna in the Irkutsk region. Trudy Irkutskoi Nauchno-issledovantel’skoi Veterinarnoi Opytnoi Stantsii (Works of the Irkutsk Experi- mental Station for Veterinary Studies), Vyp. 3, pp- 280-282 [8 species in 3 families of freshwater pulmonates were found in 20 pastoral areas] Krvotoy, N. D. 1976. Perspectives on the utilization of an experimental meth- od of hybridization in the systematics of the lymnaeids. SPZM, pp. 78 - 79 Page 496 [General observations on the functions of portions of the reproduc- tive tract in Lymnaea corviformis] Levina, O. V. 1975. Seasonal dynamics of size-age structure in some lymnae- id populations. MN, Sb. 5, pp. 86 - 88 [In the Kiev Reservoir in 1971, the maximum growth in popula- tions of Lymnaea stagnalis and L. ovata occurred in August] MasaronovskI, A. G. « M. I. GusEva 1976. On the features of the biotopes of small pond snails in the pasture areas of the Irkutsk region. Trudy Irkutskoi Nauch- no-issledovantel’skoi Veterinarnoi Opytnoi Stantsii (Works of the Irkutsk Experimental Station for Veterinary Studies), Vyp. 3, PP- 277 - 279 [Natural conditions favor fewer lymnaeids and thus decrease the incidence of fasciolariasis] Neiraku, A. A. 1976. On the morphological function of the nucleus in the early development of Lymnaea stagnalis. Ontogenez 7 (6) : 630 - 633 (ES) [Experiments are described which utilize the inhibitory effect of actinomycin on the early developmental stages in Lymnaea] Soxotoy, V. A. & N. N. Kamarpin 1977- Impulse frequency in the osphradial nerve of lymnaeid pond snails under varying osmotic conditions and different concentrations of oxygen. Vestn. Leningrad. Univ. 3: 87-90 (ES) Starozooarov, Ya. I. 1976. On the composition and systematic placement of marine pulmonates. Biol. Morya, No. 4, pp. 7-16 (ES) [Several groups of mollusks which differ phylogenetically are as- signed to the primitive pulmonates. These are the orders Ellobiida, Amphibolida, and Trimusculida. In the Ellobiida, 4 superfamilies can be distinguished: 1) Subulitoidea including Subulitidae Lind- strom, 1884 and Soleniceidae Wenz, 1938; 2) Melampodoidea, including Melampodidae Stimpson, 1851 and Otinidae H.&A. Adams, 1855; 3) Carychioidea including Carychiidae Jeffreys, 1829, Pythiidae Odhner, 1925, Anthracopupidae Wenz, 1938, Velainelli- dae Vasseur, 1880, Zaptichidae Zilch, 1959, Pedipedidae Crosse « Fischer, 1880, and Cassidulidae Odhner, 1925; 4) Ellobioidea with the families Ellobiidae H.« A. Adams, 1885 and Leucophyti- idae (a new family). The order Amphibolida contains the families Amphibolidae Gray, 1840 and Salinatoridae Starobogatov, 1970. In the order Trimusculida, there is only the single family Trimusculidae Habe, 1958. These orders of lower pulmonates, derived from primitive stylom- matophorans, can be traced in the degrees of their adaptation to aquatic habitats. The families Onchidiidae and Rhodopidae, cus- tomarily included in the Pulmonata have no relationship to that subclass and they should be placed in the subclass Dextobranchia and elevated in rank. In the order Rhodopida, only the family Rhodopidae Thiele, 1931 is included; the order Onchidiida has 3 superfamilies: Onchidelloidea, Onchidioidea, and’ Hoffmannolo- idea. In the Onchidelloidea are included the Onchidellidae E. « E. Marcus, 1960, the Onchidinidae (a new family) and Peronini- dae( also a new family) ; in the Onchidioidea there are the fami- lies Onchidiidae Rafinesque, 1815, Peroniidae Labbe, 1934, Plate- vindecidae (a new family) and Quoyellidae (another new family). Only the single new family Hoffmannolidae represents the Hoff- mannoloidea. THE VELIGER. Vol. 21; No. 4 Similarly, the Siphonariidae cannot be assigned to the Pulmonata and constitute another subclass, the Divasibranchia with the single order Siphonariida and 2 superfamilies: 1) Siphonarioidea with the families Siphonariidae Gray, 1840, Anisomonidae (a new family), and Siphonacmeidae (another new family); and 2) the Rhytido- philoidea with the single new family Rhytidophilidae. The Siphona- riida are distinguished from marine pulmonates which doubtlessly derived from primitive aquatic animals] Tataryunas, A. B. 1976. | Carotinoid content in the brain of Lymnaea stagnalis as determined by its physiological state. Obmen i funkstii vitamina A i karotina v organizme cheloveka i zhivotnikh, ikh prakt. ispol’z (Exchange and function of vitamin A and carotin in the human organism and animals, their practical use). Tezisy doklad. II. Vses. konf., Chernovits, pp. 152 - 153 BIVALVIA ALYAKRINSKAYA, I. O. 1977. On the dissolution of the crystalline style in some bi- valves. ZZ 56 (1): 23-27 (ES) [Unfavorable respiratory conditions bring about a striking dissolu- tion of the crystalline style in Mytilus galloprovincialis and Cardium edule; Donax julianae and Mya arenaria were unaffected] 1977. ‘The adaptation of littoral White Sea bivalves to desicca- tion. ZZ 56 (7): 1110-1112 (ES) [In Macoma balthica, calcium compounds in the shell are utilized to buffer the hemolymph while in Mytilus edulis the dissolution of the crystalline style takes place] Dzyusa, S. M. « M. N. Gruzova 1976. Seasonal changes in RNA synthesis and morphology of female gonads in shallow water scallops. Biol. Morya, No. 4, pp. 38-44 (ES) [The sexual cycle of Patinopecten yessoensts is divisible into stages including complete sexual inertia where there is no RNA synthesis in gonadal tissue during the winter, an active period of gametogen- esis including the growth and maturation of the oocyte and, finally, the act of spawning the oocyte itself] Frmartova, Z. A. 1976. Monograph on the deepsea bivalve genus Spinula (Dall, 1908) (Malletiidae) and its distribution in the Pacific Ocean. TRO gg: 219-240 (ES) [10 species, including S. knudseni and S. thorsoni described as new, are known. The genus occurs in the Pacific, Indian and Atlantic oceans and is notably absent from the Polar Basin and the Ant- arctic] Fiusova, G. D. « T. I. Basnurova 1976. Polymorphism in the scallop Patinopecten yessoensis in the bays of the southern and central maritime province. Vses. konf. molodykh uchenykh nuach.-tekhn. progress v. ryb. prom- sti (All-union conference of young students in scientific tech- nical progress in the fishing industry), Moscow, pp. 12 - 13 [Populations from 8 bays were studied. A hypothesis is proposed regarding the multiple allelic system for esterase of the digestive diverticula in this species] Vol. 21; No. 4 Goromosova, S. A. « A. Z. SHAPIRO 1977. Features of energy exchange of mussels in connection with their ecology. 1. S’ezd sov. okeanologov, vyp. 2, tezisy dokl. Moscow, Nauka (First session of soviet oceanologists, 2, thesis reports), p. 121 [Environmental stresses affect the rate of glycolysis in mussels] IcnaT ev, A. V. & E. S. KrasNov 1976. Investigation of the effect of temperature on growth in- crements in the shells of scallops using isotopes of oxygen. Biol. Morya, No. 5, pp. 62-78 (ES) [Measurements of isotopes of oxygen (O'8/O'®) were employed in studying growth layers in the shells of Patinopecten yessoensis, Chlamys swifti and Ch. farrei nipponensis. The dynamics of growth were correlated with seasonal parameters, such as temperature] TenaT Ev, A. V., E. V. Krasnov & I. M. RoMANENKO 1976. The correlation between the magnesium content of mus- sel shells, their growth temperatures, mineralogical composition and age. EEMB, pp. 85 - 86 [Positively correlated with a rise in temperature, the magnesium content of growth layers of the shell varies ontogenetically and seasonally. In early years the average magnesium content in calcite in the shells of Crenomytilus grayanus is 0.08 to 0.1%; at about 70 years it rises to 0.15%] Kanpyus, R. P, T. A. Petxevicy, I. A. Srepanyuk, T. P. Grosy- LEvA & L. N. SHCHERBINA 1977. Some biochemical indices of Black Sea mollusks. Gidro- biol. Zh. 13 (1): 97 - 102 [In an analysis of trace elements and amino acids, different chemi- cal compositions were noted in Mytilus galloprovincialis, Ostrea taurica and Mya arenaria in the northwestern part of the Black Sea] Kartavtsev, Yu. FE « S. M. Nixirorov 1976. | Comparisons of some data on the morphology, physio- logy, histology, and biochemistry of Crenomytilus grayanus (Dunker) in order to determine its taxonomic status more ac- curately. Biol. Morya, No. 6, pp. 13-19 (ES) [2 sympatric forms of C. grayanus were said to occur in Peter the Great Bay. The data examined do not justify the division into 2 independent species despite certain observed conchological differ- ences in shell length and obesity] Kazaxov, V. K. 1977- On insulin-like materials in cells of the intestinal epi- thelium of Unio pictorum. Zh. evolyuts. biokhimi i fiziol. 13 (4): 439 - 442 (ES) [Mammalian insulin-antisera give an immunological reaction with midgut epithelia cells of U. pictorum] Konovatova, I. V. 1976. Data on the gradual development of early mid-Jurassic Inoceramus in southern Sikhoto-Alinia. DVBPI 38 (141): 28 - 33 (ES) [Morphological changes of the shell and ligamental apparatus were observed and 4 stages were discerned] KutisHcHev, A. A. 1976. | Characteristic selectivity by larval Crenomytilus gray- anus (Dunker) before settling on the substrate. Dokl. AN SSSR 230 (3): 737-740 [Larvae actively search for a byssus secreted by mature individuals THE VELIGER Page 497 of the same species, distinguish these byssi from other mytilids and other substrates, and eventually settle. Thus, it is the mature indi- viduals which shelter the young in their byssal network which acts like a ‘kindergarden’ where the young generation is protected from predators] Mamep’yarova, G. M. 1976. | On the systematics of the family Apscheroniidae Sultan- ov. VPS, Vyp. I, pp. 134 - 140 [The group has a monophyletic origin, deriving from various species of the genus Cardium. The following arrangement is proposed: Superfamily Cardiacea; Family Apscheroniidae; Genera Parascher- onia, 5 species; Apscheronia, 4 species] Marcuuts, B. A. e G. P Pinazv 1977- The differences in the composition and nature of the albumen from the adductor muscles of bivalves. Biol. Morya No. 1, pp. 63-72 (ES) [In 26 species of bivalves, disc-jel electrophoretic analysis of muscle fibers and albumens revealed differences consonant with taxonomic distinctions, especially at the generic and familial levels] Matveeva, T. A. 1976. ‘The biology of the bivalve Turtonta minuta in different parts of its range. Biol. Morya, No. 6, pp. 33 - 39 (ES) [Data are presented regarding the habitat, depth, population struc- ture, and the time of spawning. Also the systematic placement of this species is examined] 1977. Reproduction in bivalves of the family Astartidae. IF ML 14 (22): 418-427 (ES) [Tridonta borealis (Schumacher), T: montagui (Hancock), and As- tarte elliptica (Brown) have a wide distribution in arctic and sub- arctic waters. They are characterized by a long period of gameto- genesis but a short spawning period in autumn and winter. Eggs are large (300m), yolky and enveloped by 2 jelly-like membranes which promote swelling and stickiness after fertilization. Growth takes place relatively rapidly. Protandric hermaphrodites, the As- tartidae have populations with large-sized females which increase fecundity and reproductive effectiveness] Martveeva, T. A. « N. V. Maxsimovice 1977. Characteristics of the ecology and distribution of Hta- tella arctica (Heterodonta) in the White Sea. ZZ 56 (2): 199- 204 (ES) [Preferring hard substrates, the species is widely distributed and eurybiontic, living mostly in depths between 5 and 10m, but oc- casionally to 60m. It matures sexually at the end of its first year when it reaches a length of about 14mm. Spawning takes place in June-July and the larvae settle by October. Winter mortality is is highest in young of the year. With shells measuring up to 31 mm in length, the species may live as long as 6 years] Miostavsxaya, N. M. 1977. Mollusks of the family Thyasiridae (Bivalvia, Lucin- oidae [sic] of the Arctic seas of the USSR. IFML 14 (22): 391 - 417 (ES) [The Arctic Thyasiridae consist of 3 genera and 8 species, one of which (T: phrygiana) is described as new. Detailed descriptions, a dichotomous key, ecological comments, and an analysis of zoogeo- graphic distribution are provided] Page 498 Mronov, O. G. « T. L. SHCHEKATURINA 1977. On the hydrocarbon composition of Mytilus gallopro- vincialis in the Black Sea. ZZ 56 (8): 1250-1256 [In the Black Sea, these mussels may be indicators of oil pollution inasmuch as they show a considerable uptake of hydrocarbons, in- cluding n-paraffins] Nawenko, T. Ku. « N. I. Szrm 1976. On the survival rate of young Patinopecten yessoensis on various types of substrates. EEMB, pp. 132 -134 [The accumulation of sand is a less favorable bottom for the settling and survival of this scallop than that of sand with an admixture of shells] Naumov, A. D. 1977- ‘The influence of rising temperatures on Portlandia arc- tica from two different populations in the White Sea. Biol. Morya, No. 2, pp. 74-77 (ES) [Populations from conditions where the temperature is constantly below 0°C are less able to adjust to increased temperatures than those individuals from shallow water where summer temperatures rise to 2.5°C. These differences are not sufficient to regard the dif- ferent populations as distinct physiological races] NistraTova, S. N. 1976. |The connection between the life cycle of mollusks and the sensitivity of cardiac muscle to acetylcholine. EEMB, pp. 135 - 136 [There is a correlation between the increase of sensitivity to acetyl- choline and the maturation of the gonads] Pryapko, V. P. 1976. Observations on calcium exchange in the tissues of Anodonta cygnea L. Dokl. AN SSSR B, No. 9, pp. 833 - 837 (ES) [Calcium was found in all tissues, though differential concentra- tion in the mantle was noted] Ropionov, V. F, E. D. Pavtova « M. N. ZATRAVKIN 1976. The mollusks of Lake Seliger. SPZM, pp. 133 - 134 [21 species of Unionidae and Sphaeriidae were found] Sasurov, E. G. 1976. Diurnal dynamics of the movement of the mantle fold in Anodonta cygnea in varying water conditions. Sravnit. issled. izmenenii fiziol. funktsii pod vliyaniem estestv. i sintetich. de- tergentov (A comparative study of the change of physiological function under the influence of natural and synthetic deter- gents). Yaroslavl’, pp. 64 - 67 SavcHukK, M. Ya. 1976. ‘The acclimatization of Mya arenaria in the Black Sea. Biol. Morya, No. 6, pp. 40- 46 (ES) [First reported in 1966, M. arenaria has now generated a new bio- cenose in the Black Sea. In places it reaches a density of 2000 spm per m? and a biomass of 10 kg/m?. Attaining a length of 92mm, the species may become commercially important] Suust, I. V, I. M. Kostinix « L. G. KuzmMovicu 1976. | Morphohistochemical characteristics of the sexual or- gans of Anodonta piscinalis Nilss. SPZM, pp. 170 - 172 SxaraTo, O. A. & YA. I. STAROBOGATOV 1975. | New data for constructing a system of Bivalvia. MN, Sb. 5, pp. 4-8 THE VELIGER Vol. 21; No. 4 [Modifications are suggested for the improvement of the systematic scheme of the Bivalvia as proposed by Nevesskaya, Scarlato, Staro- bogatov and Eberzin in 1971] Sxkuv’sxy, I. A. 1976. On the role of calcium in the adaptation of a marine mollusk to low environmental salinities. EEMB, pp. 165 - 166 [In Mytilus edulis, calcium is important for: the maintenance of is- osmotic pressure, the creation of membrane potentials, the activity of certain enzymes, and the neutralization of negative charges in cells] Soxo ov, V. A. 1977. Cerebral influence on the visceral ganglia via the circum- pallial nerve in Unio pictorum (Linn.). Vestn. Leningr. Univ., No. 9, pp. 85 - 88 (ES) [This neurophysiological study shows how nerve impulses from the cerebral ganglia can reach and affect the visceral ganglia via the circumpallial nerve in addition to the more usual path via the cerebro-visceral connectives] StrarosocarTov, Ya. I. 1977- Mollusca, Class Bivalvia [in] Opredelitel’ presnovod. bespozvonochnyk Evrop. chasti SSSR (Handbook of the fresh- water invertebrates of the European portions of the USSR). Plankton and Benthos. Gidrometeoizdat, Leningrad, pp. 123 - 151 [57 species in 4 families of bivalves are considered; brief ecological notes, distributional data, and synonymies are provided] TsIKHON-LUKAPINA, E. A. & T. A. LUKASHEVA 1975. Feeding of the shipworm Teredo navalis. MN, Sb. 5, 140 - 142 [A résumé of laboratory experiments] VaraksIn, A. A. 1976. Neurosecretory activity of cerebropleural ganglionic neurons in the gametogenesis of the mussel Crenomytilus gray- anus. EEMB, pp. 39 - 42 [The functional physiological condition of the nervous elements of the ganglia is closely correlated with the reproductive cycle] 1976. The neuroendocrine cycle and regulation of gameto- genesis in the Bivalvia. EEMB, pp. 43 - 45 [Crenomytilus grayanus and Patinopecten yessoensis were examined morphologically, morphometrically, and electronmicroscopically. The physiological neuroendocrine activity depends on ecological factors - partly on the water temperature. The physiological mechanisms by means of which the ecological factors influence the condition of the neuroendocrine system are unclear] 1976. On the neurosecretions of the marine bivalves Creno- mytilus grayanus (Dunkér) and Patinopecten yessoensis (Jay). Materialy VII mezhdunarod. simpoz. po neirosekretsii evolyuts. aspecty neiroendokrinal (Data of the 7" international sym- posium on neurosecretion in evolutionary neuroendocrinal as- pects), Leningrad, p. 165 [A decrease of the average parameters of the nucleus and the body of neurons of the cerebropleural, visceral, and pedal ganglia was observed at the time of sexual inactivity. Ecological factors, which condition gametogenesis and spawning, are affected by the nervous Vol. 21; No. 4 THE VELIGER Page 499 LL Se SESS system. It is surmised that control over gametogenesis and spawning can be accomplished by neuroendocrines] Vasiv’Eva, V. S. 1976. | Seasonal changes in the heat resistance of the cells of the filtering epithelium of the ctenidia of Crenomytilus grayanus. EEMB, pp. 46 - 47 [The changes are not adaptations to the absolute temperature of the water; rather, they decline at the same time as the activity of the sexual and neurosecretory apparatus declines] Vexitov, B. G., E. M. AsapuLtarv « S. K. Karyacpy 1976. Brackish water anthropogenic representatives of the genus Didacna Eichwald in Azerbaijan. VPS, Vyp. I, pp. 10-22 [A short survey of the group. A summary of published data together with personal investigations show the presence of 55 species of the genus in anthropogenic deposits. Stratigraphic analyses show the principal significance of the representatives of the genus] Vicman, E. P 1977. On the role of age structure in the maintenance of the stability of the glands [gonads] of Crenomytilus grayanus (Dun- ker). Dokl. AN SSSR 234 (5): 1222-1225 [A study of the production of larvae of this species indicates that a certain level of constancy may be maintained and that the species may be especially fit for aquaculture] Zaixo, N.N. 1976. |The dynamics of the chlorine content in the growth lay- ers of marine bivalve shells in connection with the saline con- ditions of their habitats. EEMB, pp. 73 - 74 [Chlorine ions are incorporated into layers of the shell and the rate is correlated seasonally] Zaixo, N.N., E. V. Krasnov « O. I. Nepava 1976. On the determination of the salinity of ancient marine bodies of water by study of the chemical content of molluscan shells. Biol. Morya, No. 6, pp. 61 - 63 (ES) [In an examination of 11 shells of Recent and Neogene-Quaternary specimens of Arctica islandica, the method of Raker and Valentine, with modification proposed by Zakharov and Radostev, was shown to be satisfactory] CEPHALOPODA Barskoy, I. S. 1975. Shell structure and the evolution of the ontogenesis of the cephalopods. MN, Sb. 5, pp. 171 - 173 [The development of a decidedly late embryonic shell coupled with the simultaneous appearance of 4 gills is an early evolutionary acqui- sition and possibly represents the most primitive state in cephalo- pod evolution. Bactrids and orthocerids (e.g., ammonites) have a comparable structure in the early portions of their straight shells, which apparently reflects their incomplete metamorphosis and veliger-like larvae] Dursuirs, V. V. 1976. The structure of the shell of ammonites and its onto- genetic stages revealed by electron microscopy. EEMB, pp. 57-60 [The investigation indicated that ammonites exhibit direct develop- ment] Gagvsxaya, A. V. & Cu. M. NicmaTuLuin 1976. Biotic relationships of Ommastrephes bartrami in the northern and southern parts of the Atlantic Ocean. ZZ 55 (12): 1800- 1810 (ES) [A helminthological investigation in which new representatives of didimozoid metacercaria are reported in Ommastrephes] KrivosHaPKINA, V. S. 1976. On the ontogenesis of the suture line of Zelandites. DV BPI 38 (141): 72 - 78 (ES) [In this, the first study of the change in the suture line of Zelandites, a close resemblance is noted to Gaudryceras and Eogaudryceras of the subfamily Gaudryceratinae, which supports Vidman’s supposi- tion that Zelandites was derived from Eogaudryceras] Ness, K. N. 1975. | A comparison of the cephalopod fauna from both coasts of Central America. MN, Sb. 5, pp. 156 - 158 [The deep water faunas of the Eastern Pacific (EP) and the Inner American seas (IA = Caribbean Sea, Gulf of Mexico and adjacent bodies of water) have been isolated for not less than 10 to 15 million years and the surface, sublittoral faunas for not less than 4 to 5 million years. The number of benthic and oceanic species of both areas is quite similar while the nekto-benthic, bentho-pelagic and nerito-oceanic species in the EP are sharply impoverished in com- parison with the IA. It is possible that the EP tropical fauna was reduced in the Pleistocene as a result of changes in the water cur- rents] 1975. The ecological evolution of the cephalopods. MN, Sb. SPP I5 253155 [Recent cephalopods evolved along 3 basic lines: nektonic, nekto- benthic, and benthic. Evolution and specialization did not occur as a result of the widening or narrowing of the initial adaptive zone, but rather by transfer to different zones. Mainly, evolution took place on the tropical shelf in a struggle with other organisms such as fish, and, principally, organs of locomotion were subjected to the most intense selection pressure in attempting to secure this favorable, vital habitat] 1977- The biology of Argonauta boetigeri and A. hians in the Western Pacific and the Malay Archipelago. ZZ 56 (7): 1004- 1014 (ES) [The distribution and biology of both species are similar; A. boett- geri occurs mainly in the North Equatorial Current and its branches while A. hians is found around Flores, Banda and Halma- hera. The males mature before their mantle reaches about 7mm and die after the first mating. The females mature when the mantle is about 15mm and they prolong the time of their growth and re- production. The length of the mantle and the shell of the female are compared. It is hypothesized that incubation extends for 3 days, and that the female deposits some eggs in the shell and ex- pels a group of larvae every night. The female is a specialized pelagic organism and feeds on pteropods and heteropods. Possibly they feed during the day in subsurface waters. At night, the female prefers to attach herself to living or non-living objects which float or drift on the surface, even to other females to form strings of argonauts. It is assumed that this is an adaptation to passive, noc- turnal hovering on the surface at the time of oviposition and ex- pulsion of the larvae] Page 500 Nests, K. N. 1977. ‘The horizontal and vertical distribution of oceanic ceph- alopods. 1. S’ezd sov. okeanologov, vyp 2, tezisy dokl. Moscow, Nauka (First session of soviet oceanologists, 2, thesis reports) , pp. 126 - 127 [This is a summary of extensive data on the distribution and migra- tion of oceanic cephalopods, especially in boreal and equatorial zones] Nests, K. N. « G. A. SHEvTsov 1977. __ Neritic squid of the family Loliginidae in the waters of the Soviet Far East. Biol. Morya No. 3, pp. 70-71 (ES) [A juvenile specimen of Loligo (Doryteuthis) bleekeri Keferstein was taken in the South Kurile Strait at 60 - 90m where apparently it was astray in search of food. This is the first report of this species in Soviet waters] NicMATULLIN, Cu. M. 1976. The discovery of a gigantic specimen of Architeuthis in the equatorial Atlantic Ocean. Biol. Morya, No. 4, pp. 29 - 31 (ES) [Possible reasons for the anomalous occurrence of Architeuthis out- side its range are presented] Suimansky, V. N. 1975. Changes in the cephalopod fauna at the Mesozoic- Cenozoic boundary. MN, Sb. 5, pp. 183 - 185 [At the end of the Mesozoic and the beginning of the Cenozoic, sharp changes are noted in the coleoid and ammonoid cephalo- pods, while nautiloids altered only slightly. The nautiloids acquired their present day appearance by the end of the Miocene] StaRogocarov, YA. fF. 1976. On the homology of the tentacular apparatus of ceph- alopod mollusks. Evol. Morphol. bespozvonoch. zhivot. (Evol. morphol. of invertebrates), Leningrad, pp. 50-51 [It is theorized that the tentacular apparatus of cephalopods is homologous to the lateral tentacles and their placement in the Monoplacophora] Vovx, A. N., K. N. Nesis « B. G. PaNFitov 1975. The distribution of the deep sea cephalopods in the south Atlantic and adjacent waters. MN, Sb. 5, pp. 162 - 164 {Apparently sperm whales feed on pre-spawning and spawning swarms of cephalopods. Such aggregations usually take place in waters of the continental slope, the submarine heights of the South Atlantic and near the Antarctic convergence] Zakuarov, Yu. D. & V. S. KrRIvOSHAPKINA 1976. Features of growth and the continuity of shell forma- tion in ammonoids. DVBPI 38 (141): 34-71 (ES) [3 postembryonic stages were observed and a single whorl of the shell was shown to form in 1.3 -1.7 years] SCAPHOPODA Cuistixov, S. D. 1975. Some problems of Scaphopod taxonomy. MN, Sb. 5, pp. 18 - 21 [A new system for the order Dentaliida is proposed: Superfamily Quasidentalioidea, new (1 family), Superfamily Dentalioidea (4 families) and Superfamily Rhabdoidea, new ( 3 families). Several new familial and subfamilial units are also established] THE VELIGER Vol. 21; No. 4 oz Tampa MEETING OF THE AMERICAN SOCIETY OF ZOOLOGISTS AND SoclETY OF SYSTEMATIC ZOOLOGY The American Society of Zoologists and the Society of Systematic Zoology will meet at the Holiday Inn Hotel and Convention Center in Tampa, Florida, December 27 to 30, 1979. Very low room rates are available ($19.- for single rooms and $24.- for doubles). The call for con- tributed papers will be issued in April and the deadline for abstracts is August 31. Symposia are being arranged for the following topics: Cell Volume Regulation Physiology of the Avian Egg Immunological Memory Developmental Biology of Fishes Social Signals - Comparative and Endocrine Ap- proaches Behavioral and Reproductive Biology of Sea Turtles Systematics — Ecology Interface Life History Strategies of Marine Organisms Applicability of Functional Morphology to the Construction of Classifications and Phylo- genies Analysis of Form . An all-participant party, a reception and luncheon follow- ing the ASZ Presidential Address, and divisional cash bar socials will be arranged. Plans include Commercial Ex- hibits, a Job Placement Service, and a Babysitting Service. For more information and abstract forms contact: Ms. Mary Wiley, Business Manager, American Society of Zoologists, Box 2739 California Lutheran College, Thousand Oaks, CA 91360 [telephone: (805) 492 4055] ~W.S. M. SYMPOSIUM ON THE Lire Histories oF MOLLUSKS Papers on any aspect of molluscan life histories will be considered for presentation at a symposium to be held during the joint meeting of the Western Society of Mala- cologists and the American Malacological Univn in Corpus Christi, Texas, 5 - 11 August 1979. Presentations Vol. 21; No. 4 should be concerned with an aspect of the reproduction, development, growth, or population dynamics of mollusks. Theoretical papers on the evolution of life history traits of mollusks are also invited. Opportunity for publication of abstracts or fuli length versions of papers presented at the symposium will be provided. Further information and a ‘Call for Papers’ is available from: David R. Lindberg Center for Coastal Marine Studies Applied Sciences University of California, Santa Cruz Santa Cruz, CA 95064 U.S.A. ADDITIONAL ERRATA Dr. Nelson has discovered some more errors in his paper published in our October 1978 issue: p. 203, column 1, line 4: read “Cenozoic” for “Cenzoic” Plate figures 6 and 7 (opposite p. 204) should be trans- posed p. 207, column 1, Figure 15: the block portion of the right half of the diagram should be black as in Figure 14 p. 210, column 1, Figure 18: the word “upper” should be added to the third block under “Miocene” These errata are in addition to the 3 corrections made in our January issue, p. 402. Both the Author and the Editor apologize for these errors. 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It is the stated aim of the Society to disseminate new infor- mation in the field of malacology and conchology as widely as possible at the lowest cost possible. At a Regular Membership meeting of the Society in No- vember 1968 a policy was adopted which, it is hoped, will assist in building up the Endowment Fund of the Society. 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 o00.- or more, an entire volume will be dedicated to the memory of the decedent. REGARDING POSTAL SERVICE We are much disturbed by the steadily increasing num- ber of premature claims for supposedly “missing” issues of our journal. Since we have announced on numerous occasions that our journal is mailed on the dates printed in the issues, 7.e., number 1 on July 1, number 2 on October I, number 3 on January 1 and number 4 on April 1 of each volume year, it is unreasonable to expect delivery of the issues earlier than at least one week after these dates; however, a much longer time must be allowed for delivery to addresses at various distances from Berkeley. Thus, for example, a two weeks lapse is not unusual for as short distances as 500km; and up to 3 and 4 months must be counted on for addresses in the Far East and in Africa. We are faced with the alternative of not replying to what we must consider premature claims or, if the trend con- tinues, we must increase our subscription rates to cover these additional expenses. Our past efforts at keeping the subscription rate as low as possible are, we believe, suffi- cient evidence that we simply cannot afford any other course of action. The postal service causes us enough financial losses. Therefore we urgently request that before Vol. 21; No. 4 a claim is made, the time schedule be carefully checked. We are grateful for the understanding of this difficult situation shown by many librarians and will be grateful to those who, heretofore being perhaps eager to make sure that the library receives what is coming to it, will exercise a little patience. Your harassed Editor. The Latest New Postage Rates Effective on May 29, 1978, the U.S. Postal Service in- creased rates for first, third and fourth class matter, as announced some months before. However, although not announced publicly and without notification to publishers, second class postage rates within the United States were also increased. Further, again without advance notifica- tion, postage for second class matter to the so-called PU- AS countries (Spanish-speaking countries and Brasil), which had traditionally been lower than to all other for- eign countries, was increased to the same rate. On July 6 a further increase of postage rates within the United States went into effect. This increase came also as a surprise to us, since we had assumed that the May increase was taking the place of the so-called phased in- creases which are scheduled for the sixth of July each year. It is obvious that we are forced to pass these increases on to our members and subscribers. Therefore, effective immediately, we must charge US$3.50 for postage to all addresses outside the United States, and $1.50 for all domestic addresses. Under no circumstances are we able to supply free re- placement copies of issues that fail to reach their proper destination. However, we will ship by insured mail re- placement copies at half the announced single copy rate of the particular issue plus postage. We have developed a triple check system so that, if we say that a copy has been mailed, we are absolutely certain that we delivered that copy to the post office in Berkeley and on the date we indicate. From our experience with the loss of insured mail, we are tempted to suggest that subscribers figure on a 10% reserve fund for the purchase of replacement copies. The only alternative remaining would be for us to increase subscription rates and membership dues by at least 10%. This, however, does not seem quite fair to us as some of our subscribers in almost 20 years have never failed to receive their copies. THE VELIGER Page 505 To Prospective Authors Postal Service seems to have deteriorated in many other countries as well as in the United States of America. Since we will absolutely not publish a paper unless the galley proofs have been corrected and retumed by the authors, the slow surface mail service (a minimum of 6 weeks from European countries, 8 to 12 weeks from India and Africa) may make a delay in publication inevitable. We strongly urge that authors who have submitted papers to the Veli- ger make all necessary arrangements for expeditious read- ing of the proofs when received (we mail all proofs by air mail) and their prompt return by air mail also. Since we conscientiously reply to all letters we actually receive, and since we experience a constant loss in insured and registered mail pieces, we have come to the conclusion that if a correspondent does not receive an answer from us, this is due to the loss of either the inquiry or the reply. We have adopted the habit of repeating our inquiries if we do not receive a reply within a reasonable time, that is 6 weeks longer than fairly normal postal service might be expected to accomplish the routine work. But we can not reply if we have never received the inquiry. Because of some distressing experiences with the Postal Service in recent years, we now urge authors who wish to submit manuscripts to our journal to mail them as insured parcels, with insurance high enough to cover the complete replacement costs. Authors must be prepared to document these costs. If the replacement costs exceed $400.-, the manuscript should be sent by registered mail with additional insurance coverage (the maximum limit of insurance on parcel post is, at present, $400.-). We are unable to advise prospective authors in foreign countries and would urge them to make the necessary inquiries at their local post offices. We wish to remind prospective authors that we have announced some time ago that we will not acknowledge the receipt of a manuscript unless a self-addressed stamped envelope is enclosed (two International Postal Reply Coupons are required from addresses outside the U.S. A.). If correspondence is needed pertaining to a manu- script, we must expect prompt replies. If a manuscript is withdrawn by the author, sufficient postage for return by certified mail within the U.S.A. and by registered mail to other countries must be provided. We regret that we must insist on these conditions; however, the exorbitant in- creases in postal charges leave us no other choice. Some recent experiences induce us to emphasize that manuscripts must be in final form when they are sub- Page 506 mitted to us. Corrections in galley proofs, other than errors of editor or typographer, must and will be charged to the author. Such changes may be apparently very simple, yet may require extensive resetting of many lines or even entire paragraphs. Also we wish to stress that the require- ment that all matter be double spaced, in easily legible form (not using exhausted typewriter ribbons!) applies to all portions of the manuscript — including figure explana- tions and the “Literature Cited” section. It may seem inappropriate to mention here, but again recent experience indicates the advisability of doing so: when writing to us, make absolutely certain that the cor- rect amount of postage is affixed and that a correct return address is given. The postal service will not forward mail pieces with insufficient postage and, if no return address is given, the piece will go to the “dead letter” office, in other words, it is destroyed. BOOKS, PERIODICALS, PAMPHLETS The North Pacific Cretaceous Trigoniid Genus Yaadia by Lovetia R. Saut. Univ. Calif. Publ. Geol. Sci. 119: 1 - 65; 12 pits. $7.25 (30 June 1978) Although first glance at the title and contents suggest another detailed taxonomic and nomenclatural revision- ary monograph, careful examination reveals a more broadly comprehensive and detailed study of the highly ornamented “knobby trigoniids,” an extinct group of high- ly successful (abundant and diverse) predominantly Creta- ceous bivalves. In addition to taxonomic treatment of the North Pacific species, the author provides us with a review of the world-wide occurrence of the 4 major genera of knobby trigoniids through the Cretaceous stages. Attempts to fit paleontological data to recent ecological and evolutionary theory are often less than successful, and THE VELIGER Vol. 21; No. 4 the author’s allusion to 7- and K-strategies (p. 23) is far removed from the original mathematical context of a theory that has been rather thoroughly shot full of holes by ecologists and evolutionary biologists. Paleontologists would do well likewise to abandon a theory that has even less meaning within the context of the fossil record. But this is a minor quarrel. I was most interested in the author’s analysis of trigoni- id functional morphology, because it follows closely upon the publication of SraNLEy’s (1977) analysis of the func- tional morphology of the same group. It is curious that neither author seems to have been aware of the other's work. It is even more curious that the results are so different. Without interjecting my own predilections at this point, I suggest that anyone interested in bivalve functional morphology examine and compare the basic assumptions, observational data, and conclusions of Saul and Stanley. Even given a basic agreement about the loca- tions of inhalent and exhalent currents and the foot, they have positioned their animals differently with respect to the sediment-water interface and arrive at very different conclusions with respect to the adaptive significance of the discordant sculpture in trigoniids, both with respect to its possible function as an aid in burrowing and its hydrodynamic effects. I would further suggest that the results of critical comparison may not lead the reader simply to taking the side of one author exclusively against the other without asking some critical questions of both. Whatever conclusions the reader reaches with respect to the ecological and evolutionary interpretations, this pub- lication provides an exceptionally comprehensive and use- ful taxonomic, paleogeographic, and biostratigraphic an- alysis of a group of fossil bivalves that has been heretofore very poorly understood. It should also servé to stimulate further interest in the Trigoniidae. Carole S. Hickman Department of Paleontology University of California Berkeley, CA 94720 Literature Cited STANLEY, S. M. 1977. Coadaptation in the Trigoniidae, a remarkable family of burrow- ing bivalves. Paleontology 20 (4): 869 - 899 (December 1977) 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, distributional, ecological, histological, morphological, phys- iological, taxonomic, etc., aspects of marine, freshwater or terrestrial mollusks from any region, will be considered. Even topics only indi- rectly concerned with mollusks may he acceptable. In the unlikely event that space considerations make limitations necessary, papers dealing with mollusks from the Pacific region will be given priority. However, in this case the term “Pacific region” is to be most liberally interpreted. It is the editorial policy to preserve the individualistic writing style of the author; therefore any editorial changes in a manuscript will be sub- mitted to the author for his approval, before going to press. Short articles containing descriptions of new species or lesser 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 geographical longitudes and latitudes added. Short original papers, not exceeding 500 words, will be published in the column “NOTES & NEWS"; in this column will also appear notices of meetings of the American Malacological Union, as well as news items which are deemed of interest to our subscribers in general. Articles on “METHODS & TECHNIQUES” will be considered for publication in another column, provided that the information is complete and tech- niques and methods are capable of duplication by anyone carefully fol- lowing the description given. Such articles should be mainly original and deal with collecting, preparing, maintaining, studying, photo- graphing, etc., of mollusks or other invertebrates. A third column, en- titled “INFORMATION 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 in- vited. The column “BOOKS, PERIODICALS, 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, 8!” by 11”, double spaced and accompanied by a carbon 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 accom- modate the pamphlet (which measures 512” by 8/2”), with double first class postage, should be sent with the request to the Editor. EDITORIAL BOARD Dr. Donatp P. Azszort, Professor of Biology Hopkins Marine Station of Stanford University Dr. WarrEN O. AppicotT, Research Geologist, U. S, Geological Survey, Menlo Park, California, and Consulting Professor of Paleontology, Stanford University Dr. Hans BertscuH, Curator of Marine Invertebrates San Diego Museum of Natural History Dr. Jerry DononueE, 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 Emeritus University of California, Berkeley, California Dr. Caner Hann, Professor of Zoology and Director, Bodega Marine Laboratory University of California, Berkeley, California Dr. Joet W. Hepcretu, Adjunct Professor Pacific Marine Station, University of the Pacific Dillon Beach, Marin County, California Dr. A. Myra KEEN, Professor of Paleontology and Curator of Malacology, Emeritus Stanford University, Stanford, California Dr. Vicror Loosanorr, Professor of Marine Biology Pacific Marine Station of the University of the Pacific EDITOR-IN-CHIEF Dr. Rupotr SToHLER, Research Zoologist, Emeritus University of California, Berkeley, California Dr. Joun McGowan, Professor of Oceanography Scripps Institution of Oceanography, La Jolla University of California at San Diego Dr. Frank A. Prrevxa, Professor of Zoology University of California, Berkeley, California Dr. Ropert Rosertson, Pilsbry Chair of Malacology Department of Malacology Academy of Natural Sciences of Philadelphia Dr. PETER U. Roppa, Chairman and Curator, Department of Geology California Academy of Sciences, San Francisco Dr, Criype F. E. Roprr, Curator Department of Invertebrate Zoology (Mollusca) National Museum of Natural History Washington, D. C. Dr. JupirH Terry Smitru, Visiting Scholar Department of Geology, Stanford University Stanford, California Dr. Ratrw I. Smiru, Professor of Zoology University of California, Berkeley, California Dr. CHarLEs R. STASEK, Bodega Bay Institute Bodega Bay, California Dr. T. E. Toompson, Reader in Zoology University of Bristol, England ASSOCIATE EDITOR Mrs. Jean M. Cate Rancho Santa Fe, California A AG os my = % Am: ean ~\ Dae sy \“Z NY foo. 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