^;^2_ MALACOLOGIA, 1993, 35(2); 261-313 PHYLOGENETIC RELATIONSHIPS AND GENERIC REVIEW OF THE BITTIINAE (PROSOBRANCHIA: GERITHIOIDEA) Richard S. Houbrick Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A. ABSTRACT The anatomy of seven members of the Bittium group is described, clarifying the status of the genus-level taxa comprising it. Bittium reticulatum, the type species of Bittium Gray, is described in depth, thereby establishing criteria for comparisons with other taxa of Bitliinae. The type species of Stylidium Dell and LirobiWum Bartsch, and representatives of Bittiolum Cossmann and Cacozeliana Strand are examined and compared with Bittium, s.s. Results of anatomical studies and a phylogenetic analysis using the Hennig86 and CLADOS programs, with Cehtt)ium as an outgroup, establish monophyly for Bitliinae Cossmann and reveal six different genus-level taxa. A new genus, ittibittium, from the Indo-Pacific, is proposed. Synonymies of each genus- level taxon and representative species examined are presented. Brief accounts of the ecology and zoogeography of each taxon are given. Two taxa formerly attributed to the 6/ff/um-group are herein excluded from it and referred to Cerithium Brugui?re. These are Cerithium zebrum Kiener, 1841, and Cerithium boeticum Pease, 1861. The subfamily Bittiinae Cossmann, 1906, is thought to comprise nine genera (four of which were not included in phylogenetic analyses) : Bittium Gray, 1847; Bittiolum Cossmann, 1906; Ittibittium gen. n., Stylidium Dal?, 1907; Lirobit- tium Bartsch, 1911 ; Cacozeliana Strand, 1928; Argyropeza Melvill & Standen, 1901 ; Varicopeza Gr?ndel, 1976; Zebittium Finlay, 1927. The genus Cassiella Gofas, 1987, of uncertain place- ment, is included as a possible member of the group. Key words: Bitliinae, Bittium, Cerithioidea, anatomy, taxonomy, phylogenetic analysis. INTRODUCTION Shells of most small-sized cerithilds are no- tably difficult to classify, even to familial and generic levels. There has been much confu- sion and disagreement among malacologists as to the limits and subdivisions of genus- level taxa, because most genera have been defined or based upon convergent shell fea- tures alone. Reflective of this unstable taxon- omy, unreliable curatorial systems exist in most museums, where many lots of small- sized cerlthild taxa are randomly intermixed with each other and with immature specimens of larger-shelled genera, such as Cerithium. These mixed lots frequently are assigned to the convenient "trash basket" category Bit- tium. The genus Bittium Gray, 1847, sensu lato, comprises many poorly understood species placed in the family Cerithiidae Brugui?re, 1789. The concept of Bittium has been gen- erally broad, encompassing many other di- verse genera, and opinions on the relation- ships of the genus with other small-shelled cerithiid groups have also been varied. For these reasons and due to the lack of good anatomical characters, most of the small- sized cerithioideans were left out of my anal- ysis of cerithioidean phylogeny (Houbrick, 1988). The most recent revision of the Bittium group was published by Gr?ndel (1976), who based his taxonomy and phylogeny of the group on sculptural characters of the proto- conch (embryonic spiral formation), ontoge- netic sculptural development of the teleo- conch, and overall shell form. Gr?ndel (1976) included many fossil and extinct taxa in his revision, but did not consider radular, opercu- lar, and anatomical characters of Recent taxa. Although he noted the similarities of Bit- tium and Cerithium Brugui?re, 1789, he indi- cated that Cerithium differs considerably from Bittium in shell form, sculpture, aperture, and especially in ontogenetic sculptural develop- ment. On the basis of the ontogeny of early spiral shell sculpture, Gr?ndel (1976; 38) be- lieved that genera in the Bittium group (Bit- tium, Lirobittium, Bittiolum, Semibittlum) were descendents of the Jurassic genus Procerith- ium Cossmann, 1902, of the family Procerithi- idae Cossmann, 1906. Indeed, he remarked that Bittium and Procerithium shared greater 261 262 HOUBRICK TABLE 1. Bittium-gmup genera and species used for anatomical studies (asterisk indicates type species). Genus Species Geographic Region Bittium 'reticulatum (DaCosta, 1778) BiWum /mpendens (Hedley, 1899) Bittiolum varium (Pfeiffer, 1840) BiWolum alternatum (Say, 1822) Ittibittium parcum (Gould, 1861) Lirobittium subplanatum Bartsch, 1911 Lirobittium attenuatum (Carpenter, 1864) Stylidium "esc/ir/c/ii//(Ivliddendorf, 1849) Cacozeliana 'granar?a (Kiener, 1842) Sao Miguel, Azores Honolulu, Hawaii Ft. Pierce, Florida Provincetown, Massachusetts Honolulu, Hawaii Palos Verdes, California Catalina Id., California Carmel, California Albany, Western Australia similarities in ontogenetlc sculptural develop- ment and overall shell morphology than did BiWum and Cerithium. Grundel (1976; 40) noted that the genera Argyropeza Melvill & Standen, 1901, and Varicopeza Grundel, 1976, usually placed near Bittium, were strik- ingly similar In their ontogenetlc sculptural de- velopment and morphologies to species of the Jurassic genus Cryptaulax T?te, 1869 (Procerithiidae), and stated that he consid- ered Argyropeza and Varicopeza to be Recent members of Procerithiidae. Under Procerithiidae, he assigned the Argyropeza- Cryptaulax group to the subfamily Cryptaul- axlnae Grundel, 1976, which he believed showed many of the "ancient characteristics" of the family, and the Bittium-Procerithium group to the subfamily Procerithlinae Coss- mann, 1902. Gr?nde! (1976) considered both subfamilies to have developed independently of one another and to have been separate since the Dogger (Middle Jurassic). Houbrick (1977) discussed the status of Bit- tium Gray, 1847, and included a historical re- view, extensive synonymy, and a concholog- ical redescription of the genus. This paper noted that most of the supraspecific taxa as- sociated with the Bittium group are parochial In conception and scope, based on specific rather than generic characters, and convey little or misleading phylogenetic information about the group. In the Interest of pragmatism and taxonomic parsimony, it was suggested that many of the generic and subgeneric names be abandoned or synonymized with Bittium, sensu lato, until the entire group was properly evaluated on the basis of more than shell characters. Since Gr?nders (1976) work and my paper on Bittium (Houbrick, 1977), studies on a number of Bittium-l'\ke genera and other small-shelled cerlthioldean taxa have been published: Dahlaida (Houbrick, 1978), Argyro- peza (Houbrick, 1980a), Varicopeza (Hou- brick, 1980b, 1987a), Glyptozaria (Houbrick, 1981a), Alaba and Litiopa (Kosuge, 1964; Houbrick, 1987b; Luque et al., 1988), Courra (Houbrick, 1990a), Plesiotrochus (Houbrick, 1990b), and Diala (Ponder, 1991). Many of these papers include anatomical data that have helped partially to untangle the confus- ing mixture of cehthlid genera of similar small- shelled morphology. The relationships of small-shelled species of the family Obtortlonidae Thiele, 1925, which are very similar to those of members of the BIttiinae, remain uncertain because ana- tomical characters are unknown. It is unclear If Obtortlonidae constitutes a separate family or should be included under BIttiinae. MATERIALS AND METHODS The goals of this study are threefold: first, to examine the anatomy of Bittium reticulatum (DaCosta, 1778), the type species of the ge- nus, thus setting the limits of the genus with a description of distinctive anatomical charac- ters; second, to study the anatomy of a num- ber of other "Bittium" species, thereby estab- lishing the validity or artificiality of other component groups or closely related higher taxa; and third, to make a phylogenetic anal- ysis of the group based on a morphological data set that Includes more than shell char- acters. This revision is based primarily on collec- tions of preserved material in the USNM and on living material studied In the field. Fossils representing extinct genera and species were not considered, although a brief survey of ex- tinct forms and their possible relationships to living members of the Bittium-group is in- GENERIC REVIEW OF BITTIINAE 263 eluded. The great number of species and higher category groups traditionally included under Bitiium, sensu lato, and the difficulties of obtaining good anatomical material pre- cluded an exhaustive, comprehensive ana- tomical study of all members the group. In- stead, I decided to look at representative taxa of genera assigned to the S;Wum-group com- prising species having diverse shells from widely different geographic regions. A total of seven ?/fi/um-group species representing five higher taxa (genera) from different localities were examined by dissecting live-collected material and by studying living populations in situ, where possible. These species are listed below in Table 1 and include the type species of Bittium Gray, 1847, Stylidium Dall, 1907, and Cacozeiiana Strand, 1928, and represen- tative species of Bittioium Cossmann, 1906, Lirobittium Bartsch, 1911, and a new genus, described herein. Two other species, each having a distinctive shell morphology, and considered as putative genera formerly attrib- uted to "Bitiium," S.I., were also studied in the field: "Bittium" zebrum (Kiener, 1841) from Pago Bay, Guam, and Enewetak Atoll, Mar- shall Islands; and "Bittium" boeticum (Pease, 1861), from Honolulu, Hawaii. When the soft parts of these two species were examined, they were found to lack an epipodial skirt, and the ciliated ridge tract and spermatophore bursa in the lateral lamina of the palliai ovi- duct, characters distinctive of members of the Bittium-gmup. Therefore, both species were excluded from the ?;Yf/um-group and as- signed to Cerithium Brugui?re. Due to the cur- rent alpha-level taxonomic disarray of the Bit- f/um-group, I have attempted to present a comprehensive, annotated synonymy and have illustrated the shells of the species stud- ied in this review. I hope that this will give other workers an unequivocal idea about the species and genera they represent. All specimens were dissected under water in wax-filled petri dishes using a Wild M-5 dis- secting microscope. M?thyl?ne blue was used to enhance anatomical features during dissection. Sections were made at 5 tJ.m and stained with Hematoxolin and Eosin. Photo- micrography was done using a Zeiss Photo- microscope III. The emphasis of this study is on the anat- omy of Bittium reticulatum, the type species of Bittium, s.S., which is the criterion against which other Bittium-group genera are de- scribed and compared in this paper. Descrip- tions of Bittioium, Cacozeiiana, Stylidium, Li- robittium, and a new genus described herein, are less detailed and emphasize the anatom- ical differences from Bittium reticulatum. The anatomy of the genera Argyropeza and Varicopeza is only superficially understood. Anatomical knowledge about Zebittium Fin- lay, 1927, and Cassiella remains unknown, because I was unable to obtain preserved material of species representing them; conse- quently, only the shells are considered in this review. Phylogenetic Analysis The guiding principles of this study are those of phylogenetic systematics (Hennig, 1966; Wiley, 1981). The Hennig86 computer pack- age, version 1.5, ie and bb options (copyright James S. Farris, 1988) and CLADOS, version 1.2 program (copyright Kevin C. Nixon, 1988, 1991, 1992) were used to analyse data and construct trees. Phylogenetic analysis of six genus-group taxa of the Bittiinae (Bittium, Ittibittium, Bitti- oium, Lirobittium, Stylidium, and Cacozeii- ana) was undertaken using 21 morphological characters comprising 51 character states de- rived from the shell, operculum, radula, and soft anatomy of the taxa listed in Table 1. Ini- tially, there were 30 characters, but these were reduced to 21. Seven of the 21 charac- ters were multi-state characters. Autapomor- phies defining terminal branches, which were not part of multistate series, were not included in the analysis, but were retained for the di- agnosis of each genus-group taxon. Multi- state characters were unordered. Genus-Group Taxa Analysed Six genus-group taxa were included: Caco- zeiiana, Lirobittium, Stylidium, Bittium, Ittibit- tium, and Bittioium (Table 1). The phyloge- netic analysis excluded poorly known genera that have been assigned without justification to Bittiinae, such as Zebittium and Cassiella. Although the shell morphologies, opercular and radular characters of Argyropeza and Varicopeza have been well studied (Houbrick, 1980a, 1980b), these genera also were left out of the analysis because of lack of anatom- ical data. Outgroup Selection The genus Cerithium Brugui?re, family Cer- ithiidae F?russac, 1819, was selected as the 264 HOUBRICK TABLE 2. Comparison of dentition of radular teeth among genera (C signify no. of denticles). central or main cusp; numbers Taxon Rachidian Lateral Inner Ivlarginal Outer Marginal Bittium Bittiolum IttibiWum LirobiWum Stylidium Cacozeliana Argyropeza Varicopeza 2-3+C+2-3 3 + C + 3 2 + C + 2 6 + C + 6 2 + C + 2 2 + C + 2 2-3+C+2-3 3-4+C+3-4 1+C+3-6 2+C+3-4 1+C+3-4 6 + C + 15-17 1+C+3-4 1+C + 3-4 1+C+5-6 1+C+5-6 3-4+C+4 3-4+C+2-3 2 + C + 3 15-19 + C + 5-6 4-5+C+3 5-6+C+3-4 5-6+C+4-5 3-4 + C + 3 3-4+C+O 6 + C + O 5 + C + O 15-19 + C + O 4 + C + O 4 + C + O 5-6+C+O 3 + C + O outgroup to root the trees generated by the analyses. The BiWum-group traditionally has been considered as a subfamily (Bittiinae) of Cerithiidae by various authors (see below, for history). Cerithium, subfamily Cerithiinae, is the most appropriate group to use for out- group comparison, because it is the closest sister group that is well known anatomically. The anatomy of Cerithium species has been described by Houbrick (1971, 1978, 1992) and is very similar to that of Bittiinae mem- bers. However, Cerithium species have more generalized and less complex external fea- tures. Several external anatomical features of members of the S/tt/um-group, such as a metapodial mucus gland, and the epipodial skirt and associated papillae, are lacking in Cerithium. The anatomy of such small-sized snails as Bittium may be highly derived and/or modified due to their reduction in size. Cerith- ium species are generally much larger ani- mals than "Bittium" species, but a number of species are very small and often are confused with "Bittium" species. Among small-shelled cerithioideans, Litiopa and Alaba, family Litiopidae, were considered as possible outgroup candidates. These small snails have external features, such as an epipodial skirt and epipodial tentacles, similar to those seen among members of the Bittii- nae, and are well known anatomically; how- ever, they differ from bittiid species in internal anatomy (Kosuge, 1964; Houbrick, 1987b; Luque et al., 1988). Phylogenetically, Litiop- idae is far removed from the family Cerithiidae (Houbrick, 1988; 114), and is therefore re- jected as a suitable outgroup. Another group of small-shelled species, the Dialidae, was also considered as a possible outgroup. However, only one species is known anatomically (Ponder, 1991), and Healy (1986) has shown that the parasperma- tozoa of Diala are unique and highly derived among cerithioideans. Ponder's (1991) phy- logenetic analysis showed that dialids were closely related to litiopids and far removed from Cerithiidae (Ponder, 1991; 514). Diaia was therefore rejected as an outgroup. Characters The characters listed below comprise three categories; shell characters (1-5), anatomical characters (6-19), reproductive characters (20-21). Radular characters were eliminated from the final analysis because of their au- tapomorphic condition. Nevertheless, radular characters are important diagnostic charac- ters of genera and are summarized in Table 2. Because the polarities of multistate charac- ters were largely speculative, all character states were left unordered; i.e., the integer assignment was arbitrary. The coding of these characters and their states are pre- sented in Table 3. An annotated list of the morphological characters and character states used in the phylogenetic analysis is presented below; Shell Characters: 1. Shell sculpture?0 = spiral; 1 = cancellate. Most members of the subfamily are characterized by a markedly cancellate shell sculpture, in contrast to Cer- ithium species where spiral elements domi- nate sculptural patterns (Houbrick, 1992). Ex- ceptions are species of the genera Stylidium and Ittibittium, where spiral sculpture domi- nates and axial ribs are either lacking or poorly developed. 2. Anal canal?0 = well developed; 1 = weakly developed or missing. A well-devel- oped anal canal is present in Cerithium mem- bers (the outgroup), but occurs only in two genera of the S/fi/um-group, Cacozeliana and Varicopeza, and is exceptionally well devel- oped in the latter genus (Houbrick, 1980b). GENERIC REVIEW OF BITTIINAE 265 TABLE 3. Data matrix derived from morphological characters of species representing six genus-group taxa of Bittiinae. Cerithium is the outgroup. Character Taxon 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Outgroup 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bittium 1 1 0 1 0 1 1 0 0 0 2 0 1 2 1 1 1 1 1 0 0 IttibiWum 0 1 0 1 0 0 1 0 0 1 2 1 0 1 1 0 0 0 1 1 1 Stylidium 0 1 1 1 2 0 0 1 1 0 1 0 2 1 1 1 1 1 1 0 1 Cacozeliana 1 0 1 0 2 2 2 0 0 0 1 0 0 0 0 1 1 1 0 0 ? BiWolum 1 1 0 1 1 0 1 0 0 1 3 0 1 1 1 0 1 1 1 0 0 LirobiWum 1 1 1 1 0 1 0 1 1 0 1 1 2 1 1 0 1 1 1 2 1 3. Varices?0 = present; 1 = absent. Va- rices, thickened, former growth lines, are a common feature of most cerithiids and occur among members of Bittiinae with the excep- tion of Lirobittium and Stylidium. 4. Anterior canal?0 = well developed; 1 = weakly developed. The anterior siphonal canal is a strong feature on most cerithiids, but in smaller-shelled taxa frequently is poorly developed (most Bittiinae) or absent (Cass- iella, Cerithidium). 5. Protoconch sculpture?0 = two spiral lirae; 1 = one spiral lira; 2 = entirely smooth. Most outgroup species have strong spiral sculptural elements on their protoconchs (Houbrick, 1992). Bittiinae genera range from species with spiral sculpture to those having only one weak spiral lira or no sculpture, but this is probably reflective of the type of devel- opment. Anatomical Characters: 6. Opercular mor- phology?0 = ovate shape; 1 = round, cir- cular shape; 2 = round shape with fringed spiral edges. Cerithium species have oper- cula with an ovate shape (Houbrick, 1992), and it is thought herein that the more circular shape observed among several S/ff/um-group taxa are modifications due to size reduction, although this is not always the case (excep- tions in Ittibittium and Bittiolum, both small shelled genera). The spirally fringed condition seen in Cacozeliana departs from the norm and is probably derived. 7. Snout shape?0 = wide; 1 = narrow, elongate; 2 = short, narrow. This character is a variable feature among cerithiids. Cerithium species usually have large, wide, muscular snouts (Houbrick, 1992), whereas they tend to be narrow and elongate in members of the Bittiinae, especially among taxa of the Bittium clade {Bittium, s.S., Ittibittium, Bittiolum). 8. Cephalic tentacle length?0 = elongate; 1 = short. Among cerithiids and the Bittiinae, cephalic tentacles are usually elongate and much longer than the snout, but in the eastern Pacific genera Lirobittium and Stylidium, the tentacles are much shorter than the length of the snout. 9. Eye size?0 = normal; 1 = small; 2 = large. Most cerithiids have eyes of normal size, but in such deep-water species as Argyropeza and Varicopeza, the eyes are very large, pos- sibly an adaptation to water depth and poor light. In contrast, the eyes of Styliodium and Lirobittium species are exceptionally small. 10. Metapodial mucus gland?0 = absent; 1 = present. Although this structure is absent in the outgroup, it does occur among a few other cerithioidean groups (Litiopidae [Alaba, Litiopa], Cerithiidae [Colina]; Houbrick, 1987b, 1990a, respectively). This gland may be an adaptation to an algal and/or high en- ergy habitats. Species having a metapodial gland are known to use the mucus thread se- creted by the gland to anchor themselves while they climb about the algal fronds (Houbrick, 1987b, 1990a), 11. Epipodial skirt?0 = rudimentary; 1 = well developed, smooth; 2 = well developed, papillate along edges; 3 = well developed, scalloped. Cerithium species have a weak operculigerous lobe on the rear of the foot, which is here Interpreted as a rudimentary posterior epipodial skirt. In Bittiinae species, the skirt extends forward along the sides of the foot to form a fully developed epipodial skirt. An epipodial skirt occurs also among small-shelled members of the Litiopidae (Ko- suge, 1964; Houbrick, 1987b; Luque et al., 1988) and the Dialidae (Ponder, 1991). Al- though this character is homoplastic among cerithioideans, an epipodial skirt is character- istic of Bittiinae. 266 HOUBRICK TABLE 4. Comparison of developmental features among Bittiinae genera and species. Max. Shell Protoconch Developmental Taxon Length Sculpture Type Egg Size Bittium reticulatum 15 mm 2 spirals planktonic 0.1 mm IttibiWum parcum 6 mm 2 spirals direct 0.2 mm Bittiolum varium 7 mm 1 spiral planktonic 0.1 mm Lirobittium subplanatum 10 mm 2 spirals direct 0.5 mm Stylidium eschhchtii 17.5 mm smooth direct 0.2 mm Cacozeliana granar?a 24 mm smooth planktonic 0,1 mm Argyropeza divina 7.6 mm 2 spirals planktonic ? Varicopeza vahcopeza 10 mm 1 spiral planktonic ? 12. Ovipositor?0 = present; 1 = absent. This gland, although common among cerithio- ideans, is absent in some taxa, such as those having internal brooding (Houbrick, 1987c). The absence of an ovipositor in females may be falsely scored, as it is thought that its pres- ence can be easily ascertained only during breeding season; moreover, this gland is also difficult to detect in some preserved speci- mens. Among Bittiinae, the ovipositor is ab- sent only in Ittibittium and Lirobittium. 13. Osphradial morphology?0 = bipecti- nate; 1 = monopectinate; 2 = vermiform. This character varies greatly among Bittiinae genera. Although the osphradium in Cerith- ium species is bipectinate, it is vermiform among most other cerithioidean families, such as the estuarine Potamldidae and fresh- water families Thiaridae and Pachychilidae (Houbrick, 1988, 1991). 14. Osphradial length?0 = equal to ctenidial length; 1 = a little less than ctenidial length; 2 = one-half the ctenidial length. This is a highly variable character, but often diag- nostic of some taxa. No overlap among char- acter states was detected in the species stud- ied. 15. Zygoneurous nervous system?0 = absent; 1 = present. Bouvier (1887) docu- mented a zygoneurous condition among some cerithiids, and this was summarized by Houbrick (1988). Zygoneury is absent in Cer- ithium, and in all Bittiinae except for Bittiolum. 16. Common opening to sperm pouch and seminal receptacle openings?0 = close to- gether; 1 = far apart. In Stylidium and Liro- bittium, the openings have a wide separation, whereas in Bittium they are not as far apart. In other bittiids and in most other cerithiids, the openings are close together. 17. Spermatophore bursa location?0 = located in medial lamina; 1 = located in lat- eral lamina. The spermatophore bursa is found in the lateral lamina in most members of the Bittium-group, but in Ittibittium and in all other known cerithiids, it occurs in the medial lamina (Houbrick, 1988). 18. Ciliated ridge tract?0 = absent; 1 = present. This structure, one of the synapo- morphies defining Bittiinae, is lacking in Ittibit- tium members and in most other cerithiids. 19. Seminal receptacle with grape-like mor- phology?0 = present; 1 = absent. This grape-like configuration may not represent a distinct morphology, but may be due to the highly filled condition of the receptacle. This condition occurs only in Cacozeliana. Reproductive Characters: 20. Spawn mor- phology?0 = formed into gelatinous string wound into mass; 1 = short gelatinous tube; 2 = balloon-like cluster. A gelatinous string mass is the common spawn morphology seen among cerithioidean taxa and within Bittiinae. The balloon-like cluster of eggs in members of Lirobittium is unique, whereas a short ge- latinous tube morphology is seen only in It- tibittium: both taxa have few, large eggs and undergo direct development (Table 4). 21. Type of development?0 = planktonic; 1 = lecithotrophic (demersal/direct). Most members of the outgroup have a planktonic GENERIC REVIEW OF BITHINAE 267 Cacozeliana Lirobittium Stylidium Bittium Ittibittium Bittiolum FIG. 1. Cladogram showing relationships among six genera of Bittiinae, using Cerithium as the outgroup (L = 41 ; C! = 70; Rl = 53; trees two. Numbers to left of black bars indicate characters: those to right of bars represent character states. Only characters with a CI of 100 are shown). larval phase In their development. It is thought that planktotrophy can evolve to lecilhotrophy but not vice-versa (Strathmann, 1978). Direct developers have larger, fewer eggs per spawn mass (Table 4). RESULTS Phylogenetic analysis resulted in two equally parsimonious trees, each with a length of 41 steps, a consistency index of 70, and a retention index of 53 (Fig. 1). The num- ber of steps and the consistency indices of each character used in the construction of the cladogram are shown in Table 5. The support- ing branches of both cladograms had identi- cal tree topologies except for the clade sup- porting Bittium, Ittibittium, and Bittiolum. In the first tree, illustrated herein (Fig. 1), Ittibittium and Bittiolum are sister groups of Bittium, while in the second tree, Bittium and Bittiolum are sister groups of Ittibittium. Both analyses strongly support the recognition of six genus- level taxa. The monophyly of Bittiinae is es- tablished by three synapomorphies (11[1], 18[1], 20[0]) and one homoplastic character (17[1]). The layout of the palliai oviduct, dis- cussed in greater detail below, is the source of two good synapomorphous characters: a ciliated ridge tract and a spermatophore bursa in the medial lamina. An epipodial skirt, while distinctive of the Bittium-group, is plesi- omorphic, because it occurs also in other cer- ithioidean groups. Cacozeliana stands apart at the base of the cladogram from the other taxa and is closest to Cerithium, the outgroup. Cacozeliana is de- fined by two autapomorphous characters (6[2], 7[2]) and by two homoplastic characters (5[2], 16[1]). Cacozeliana is well separated from all other genera of Bittiinae higher on the tree by five synapomorphies (2[1], 4[1], 14[1], 15[1], 19[1]) and with one homoplastic char- acter (13[1]). The Lirobittium-Stylidium clade, which is 268 HOUBRICK TABLE 5. List of steps and consistency indices of characters used in construction of cladogram. Character 1 2 3 4 5 6 7 8 9 10 11 Steps 3 1 2 1 3 3 2 1 1 1 3 C.I. 33 100 50 100 66 66 100 100 100 100 100 Character 12 13 14 15 16 17 18 19 20 21 Steps 2 3 2 1 3 2 2 1 2 2 C.I. 50 66 100 100 33 50 50 100 100 50 geographically confined to the west coast of North America, is supported by two synapo- morphies (8[1], 9[1]), and two homoplastic characters (13[2], 21 [1]) In this clade, Stylid- ium is poorly defined by three homoplastic characters (1[0], 5[2], 16[1]), whereas Lirobit- tium is better founded on one autapomorphy (20[2]) and three homoplastic characters (6[1], 12[1], 16[0]). The Bittium clade is supported by one sy- napomorphy (7[1]) and two homoplastic char- acters (3[0], 13[1]). Bittium, s.S., is defined by one autapomorphy (14[2]) and three ho- moplastic characters (2[0], 12[1], 18[1]). It- tibittium and Bitiiolum, the sister taxa to Bit- tium, are separated from it by one synapomorphy 10[1]). Bittiolum is supported by two autapomorphies (5[1], 11 [3]) and two homoplastic characters (11 [3], 16[0]). A sin- gle autapomorphy (20[1]) and six homoplastic characters (1[0], 12[1], 13[0], 16[0], 17[0], 18[0], 21 [1]) define Ittibittium. The characters listed above are those derived only from the data matrix (Table 3) used in the construction of the cladogram (Fig. 1). Other autapomor- phies defining terminal branches but not pari of multiState series were not included in the data matrix. These characters are given un- der the diagnosis of each genus in the sys- tematic portion of this paper. DISCUSSION The phylogenetic analysis of morphological characters of the species in Table 1 resulted in recognition of six different morphological groups (Fig. 1), which are herein interpreted as genus-group taxa under the stJbfamily Bit- tiinae Cossmann, 1906. Generic names al- ready exist for five of these groups: Bittium Gray, 1847; Bittiolum Cossmann, 1906; Ca- cozeliana Strand, 1928; Stylidium Dall, 1907; and Lirobittium Bartsch, 1911. A new genus, from the Indo-Pacific, is described herein. All of the above genera, with the exception of Stylidium, are defined by autapomorphous characters. If the cladogram shown in Figure 1 is interpreted strictly, Ittibittium and Bittiolum may be regarded as subgenera of Bittium; however, because this is a preliminary revi- sion of the Bittium-group, based on only a few representatives of each genus, and not in- cluding other poorly known taxa, it is best not to assign differential rank to genus-group taxa at this stage. Therefore, I have decided to treat all terminal nomina as full genera. As noted in an earlier paper (Houbrick, 1977), other genus-level taxa have been pro- posed under the Bittium-group or are thought to be linked closely to it. Many of these taxa are synonyms of Bittium-gmup genera de- scribed herein or have been proposed for fos- sils. The subfamily Bittiinae, as understood in this paper, is thought herein to comprise nine, possibly ten, Recent genus-group taxa: Bit- tium Gray, 1847; Bittiolum Cossmann, 1906; Ittibittium gen. n.; Stylidium Dall, 1907; Liro- bittium Bartsch, 1911; Cacozeliana Strand, 1928; Argyropeza Melvill & Standen, 1901; and Varicopeza Gr?ndel, 1976. The genera Zeblttium Finlay, 1927, and Casslella Gofas, 1987, are provisionally referred to Bittiinae until more information is available. Argyropeza and Varicopeza have been treated previously by Houbrick (1980a, 1980b, 1987a), but their anatomy remains poorly known and they are not described in great detail here. An epipodial skirt has been recorded in Varicopeza crystallina (Houbrick, 1987a: 80), but due to poorly preserved ana- tomical material, this structure could not be ascertained in Argyropeza species; however, the radula of Argyropeza species (Houbrick, 1980a) is similar to those of members of the BIttlum-gmup. Anatomical knowledge about potential Blt- tlum-group species as yet unstudied, such as Casslella from the eastern Atlantic, Zeblttium from New Zealand, and the many species of small-shelled, Bittium-Wke cerithioideans from the Indo-Pacific, may reveal even more new genus-level taxa to be included under Bittii- nae. GENERIC REVIEW OF BITTIINAE 269 SYSTEMATIC TREATMENT OF BITTIINAE The species studied have been placed into groups (genera) according to the above phy- logenetic analysis. The type- or representative species of each genus is described, and notes on reproductive biology and ecology are in- cluded, when possible. Shell-length measure- ments for each species represent the largest specimen obsen/ed. Representatives of other genera for which anatomical material was lacking are described from shell morphology and radular morphology, if available. BITTIINAE COSSMANN, 1906 Bittiinae Cossmann, 1906: 61. Procerithiinae Cossmann, 1906, sensu Gr?n- del, 1976 (in part). Diagnosis Shell small, turreted, narrowly elongate to pupate, with moderate spiral and axial sculp- ture frequently cancellate and/or beaded. Ap- erture with short but distinct anterior canal. Spiral sculpture usually 4-5 spiral cords per whorl. Animal with epipodial skirt, opercular lobe, and palliai oviducts comprising large sperm bursa and seminal receptacle in pos- terior part of medial lamina, and spermato- phore bursa and ciliated ridge tract in poste- rior lateral lamina. Ciliated gutter leading from oviduct down right side of foot in females. Glandular ovipositor at base of right side of foot in most species. Nervous system dialy- neurous. Spawn consisting of gelatinous, winding strings. Taxonomic Remarks The S/fi/um-group (Bittiinae Cossmann, 1906) has been placed under Cerithiidae by nearly all authors (Cossmann, 1906; Thiele, 1929; Wenz, 1938; Golikov & Starabogatov, 1975; Ponder & Waren, 1988), except Gr?n- del (1976), who assigned the group to the Ju- rassic family Procerithiidae Cossmann, 1906 (erroneously cited by Cossmann as 1905). He allocated 12 genus-group taxa to the subfam- ily Procerithiinae (= Bittiinae). Of these, Bit- tlum, Bittiolum, SemibiWum and Procerithium were treated as full genera; Cerithidium Mon- terosato, 1884, ?asb/Wum Gr?nde!, 1976, Li- robittium Bartsch, 1911, Cacozeliana Strand, 1928, and Stylidium Dall, 1907, were consid- ered to be subgenera of Bitiium. The extinct taxa Cosmocerithium Cossmann, 1906, In- fracerithium Gr?ndel, 1974, and Rhabdocol- pus Cossmann, 1906, were treated as sub- genera of Procerithium. Gr?ndel (1976) also included Argyropeza Melvill & Standen, 1901, Varicopeza Gr?ndel, 1976, and the extinct genus Cryptaulax Gr?ndel, 1976, with sub- genera Pseudocerithium Cossmann, 1884, and Xystrella Cossmann, 1906, in the Bittium group under the subfamily Cryptaulaxinae Gr?ndel, 1976. Excluding the Jurassic taxa, the Recent genera Argyropeza and Varico- peza should probably be included in the Bit- tiinae, because the few morphological and anatomical characters known about these taxa strongly suggest affinity to this subfamily. The other extinct genus-group taxa and Pro- cerithium should be excluded from Bittiinae, because the evidence supporting a relation- ship of these taxa with the S/rt/um-group is based solely on the ontogenesis of spiral sculpture as seen on the early shell spire, a character which is, at best, tenuous: more characters are needed to lend credence for such a relationship. While Gr?ndel's (1976) hypothesis poses interesting questions, it is founded mostly on shell sculpture, which is taxonomically informative but potentially phy- logenetically misleading. Considering the Ju- rassic age of the Procerithium group and the great likelihood of homoplasy in shell mor- phology, the belief that the Bittium- and Pro- cerithium- groups are of the same lineage is largely speculative, cannot be falsified, and should not be accepted as evidence for a phy- togeny (Houbrick, 1988). The name Elassum Woodring, Bramlette & Kew, 1946, has been traditionally associated with the Bittium-group in the literature, and was proposed by Woodring et al. (1946; 68) for Pleistocene and Recent material from southern California previously named Bittium californicum Dall & Bartsch, 1901, and origi- nally assigned to the subgenus Elachista Dall & Bartsch, 1901. Bittium californicum is the type species of Elachista by monotypy. How- ever, as Elachista is preoccupied, a new name, Alabina Dall, 1902, was proposed to replace it. Woodring et al. (1946) did not be- lieve the taxon californicum Dall & Bartsch, 1901, was an Alabina and thus proposed Elassum to accomodate it, noting that the species was more Bittium-Wke than Alabina- like. Because Elachista, Elassum, and Alab- ina have the same type species, Elassum be- comes a junior synonym of Alabina. The shell of the type species somewhat resembles 270 HOUBRICK those of members of the Bitlium-group, and I concur with Woodring et al. (1946) that it pos- sibly should be included as a component ge- nus of the Bittium-group; however, as there is no preserved material of living animals of this taxon to confirm this supposition, Alabina [ = Elassium] is not further treated herein. Houbrick (1977: 103) initially placed 13 nomina into the synonymy of Bittium, sensu lato. Subsequent studies on the BiWum-group and evidence derived from anatomical char- acters presented herein now allow exclusion of six genera originally included in that syn- onymy and a more focused diagnosis of Bit- tium, s.S. An annotated list of taxa previously included in the Bittium-group, but now ex- cluded, is presented below (Jurassic genera not included): 1. Bittinella Dall, 1924 (type species: Bittium hiloense Pilsbry & Vanatta, 1908). The type species of this genus is a rissoid of the genus /sse//e//a Weinkauff, 1881, subfamily Rissoin- inae (Ponder, 1985: 95; Kay, 1979: 80). Bit- tium parcum Gould, 1861, has been errone- ously assigned to Bittineila (see below). 2. Bittiscalia Finlay & Manwick, 1937 (type species: Bittium simplex Marshall, 1917). It is unclear to which group this extinct species should be assigned. Although Finlay & Mar- wick (1937: 44) placed it under Cerithiidae, they noted its similarity to Zeacumantus Fin- lay, a batillariid (Houbrick, pers. obser.). Their drawing of the type species (Finlay & Marwick, 1937: pi. 5, fig. 20) shows a shell with an an- terior canal that is a wide shallow notch, similar to poorly developed anterior canals seen in some Bittium and Alabina species. Because this is a fossil, we may never know with cer- tainty the correct family assignment. Although the authors placed it under Cerithiidae, they were obviously equivocal about this assign- ment. It is best to leave Bittiscalia under the broader category of Cerithiidae and to exclude it from the more narrow assignment of Bittinae. 3. Brachyblttium Weisbord, 1962 (type spe- cies: Bittium [Brachyblttium) caraboboense Weisbord, 1962). The type species, a fossil, appears to be an immature or fragmentary Cerithlum species, judging from its illustration (Weisbord, 1962: pi. 15, figs. 5-6). 4. Cerithidium Monterosato, 1884 (type species: Cerithlum submamillatum Rayneval & Ponzi, in Rayneval etal., 1854). Cerithidium was introduced by Monterosato (1884) who noted that it was characterized by a rounded aperture and lack of an anterior canal. Mon- terosato listed a single species under the ge- nus, Cerithlum submamillatum Rayneval & Ponzi, 1854, which he considered a synonym of Turritelia pusllla Jeffreys, 1860. As Gofas (1987: 110) remarked, the former name was originally given to a Pleistocene fossil which is not conspecific with the Recent species. Go- fas (1987) remarked that the designation of Cerithlum submamillatum as the type species of Cerithidium by Cossmann (1906) should prevail over that of Turritelia pusllla by Wenz (1940). I agree with Gofas (1987: 109-110) that both species are congeneric and have sculpture similar to Bittium reticulatum; how- ever, in a Cerithidium species examined by Ponder (Ponder, in litt.), the female palliai ovi- duct was closed, which is very different from the open systems known in all other members of Bittiinae. A closed palliai oviduct has not yet been demonstrated in the type species of Cerithidium, but on the basis of the closed system noted by Ponder, Cerithidium is ex- cluded provisionally from Bittiinae. 5. Dahiakia Biggs, 1971 (type species: Dahiakia lellae Biggs, 1971). The type spe- cies is a junior synonym of Cerithlum proteum Jousseaume, 1930 (Houbrick, 1978), and I believe both names are probable synonyms of Cerithlum scabridum Philippi, 1848. 6. EubiWum Cotton, 1937 (type species: Bittium lawleyanum Crosse, 1863) [not Eublt- tium Cossmann, 1902). The syntypes of the type species of this genus (MNHN, Paris) are Batlllariella estuarlna (T?te, 1893), which is a batillariid (family Batillariidae), and not closely related to Cerithiidae. In any case, the name Eubittium Cotton is a secondary homonym. 7. Paracerlthium Cotton, 1932 (type spe- cies: Bittium lawleyanum Crosse, 1863) [not Paracerlthium Cossmann, 1902]. This taxon is a secondary homonym and has the same type species as the previous taxon, which is a batillariid. 8. Sundablttium Shuto, 1978 (type species: Cerithlum fritschi Boettger, 1883). It is highly unlikely that this fossil genus is related to the Bittium group. Shuto himself (1978: 152) was equivocal in assigning it to Bittium. The fig- ures of C. fr/iscA)/depicted by Martin (1914: pi. 5, figs. 132-134) suggest an Abyssochrysos species, but this assignment needs confirma- tion by examination of the type material. Discussion The subfamily Bittiinae is characterized by small-shelled species generally having can- cellate sculpture and short canals. Monophyly GENERIC REVIEW OF BITTIINAE 271 for Bittiinae is tentatively established by the synapomorphous layout of the palliai oviduct (see description under Bittium reticulatum; Fig. 6C); i.e., the presence of three sperm chambers: a large bursa (1), and smaller seminal receptacle (2) in the posterior half of the medial lamina, and a spermatophore bursa (3) in the posterior lateral lamina. The position of the spermatophore bursa in the lateral lamina appears to be a unique synapo- morphy defining Bittiinae, but this needs to be confirmed by observation of spermatophores in the bursa in other members of the subfam- ily. This character does not occur in Ittibittium, a new genus described herein; thus, it had a CI of 50 in the analysis. The ciliated ridge tract (Fig. 6B, C, ctr) on the lateral lamina epithe- lium leading into the spermatophore bursa is also a synapomorphy defining Bittiinae. This is an uncommon feature among cerithioide- ans, and is unusually long. Some plesiomor- phic characters, such as the well-developed epipodial skirt and epipodial tentacles, occur in other cerlthioidean groups, but in combina- tion with the above synapomorphous fea- tures, are characteristic of the Bittiinae. Ittibit- tium, new genus, deviates from other members of the subfamily in having the albu- men gland protrude beyond the posterior mantle cavity into the visceral coil. In other respects, it generally agrees with the remain- ing genera of the Bittiinae. The Recent genera treated herein are each characterized by external anatomical charac- ters (Fig. 2), which allow easy classification of living animals. Two genera of the subfamily (Bittlolum and Ittibittium, gen. n., have a large metapodial mucus gland marked by an elon- gate slit in the middle of the sole (Fig. 2), lead- ing deep into the center of the foot. While the epipodial skirt and opercular lobe are charac- teristic of Bittiinae, these characters and the metapodial mucus gland also occur in spe- cies of Alaba H. Adams & A. Adams, 1854, and Litiopa Rang, 1829 (Litiopidae Fischer, 1885), in members of Colina H. Adams & A. Adams, 1854 (Cerithiidae F?russac, 1819), and in species of Plesiotrochus Fischer, 1878 (Plesiotrochidae Houbrick, 1990b) (Kosuge, 1964; Houbrick, 1987b; Luque et al., 1988; Houbrick, 1990a, 1990b, respectively). I have previously pointed out the anatomical fea- tures shared by Colina with members of the Bittiinae (Houbrick, 1990a: 50-51). Species of Plesiotrochus Fischer, 1878, also have a papillate epipodial skirt and an elongate metapodial slit leading into a large metapodial mucus gland, but differ considerably from members of the Bittium-group in other ana- tomical characters (Houbrick, 1990b: 247- 248), and are an unusual family. The relationship of the ?/fi/um-group to other small-shelled cerlthioidean genera such as Scaliola A. Adams, 1860, and Finella A. Adams, 1860, remains unclear because the anatomy of these taxa is still unknown. Ponder (1991) recently described the anatomy of a species of Diala A. Adams, 1861, which re- sulted in his recognition of a separate family, Dialidae Ludbrook, 1941. According to Ponder (1991: 504-506), Diala species have a weak epipodial fold (epipodial skirt), a pair of lateral opercular lobes, and a posterior opercular flap, which appear to be homologous with the epipodial skirt and opercular lobe described in the Bittiinae members above. However, unlike the situation in Bittiinae, Diala species lack the metapodial mucus gland and the glandular ovipositor on the right side of the foot in fe- males. Additionally in Diala species, the lateral lamina of the palliai oviduct does not have a sperm pouch and the paraspermatozoa are unique among Cerithioidea (Healy, 1986). The rachidian radular tooth of most mem- bers of the S/ff/um-group is characterized by being wider than tall and usually has a basal plate with concave sides. This differs from the hour-glass shape of the rachidian tooth found in small-sized species of Diala, Litiopa, Alaba, and Varicopeza (Ponder, 1991: fig. 3F, G; Houbrick, 1987a: figs. 14, 19; 1987b: figs. 9, 10), taxa frequently confused with Bittium- group members. For dental cusp patterns among Bittiinae taxa, see Table 2. Although members of Bittiinae are primarily grazers of epiphytic microalgae, many species appear to feed on particulate matter gathered by cilia and mucus on the antehor ctenidial filaments when the animal is stationary. The ultrastructure of the sensory epithelium of the osphradia of members of the Bittium- group is typical of Cerithioidea, and Haszpru- nar (1985:479) has shown that the osphradial cells bear paddle cilia. The osphradial classi- fication of Bittiinae species falls under Hasz- prunar's (1985) group "S?2." Haszprunar (1985) repeated the Fretter & Graham (1962: 367) statement that the osphradium is a "sim- ple brown ridge," but this is not concordant with my observations of the pectinate condi- tion in many taxa of the group. The phylogeny and relationship of mem- bers of the Bittium-group will remain unclear until the anatomy of other cerlthioidean taxa is 272 HOUBRICK BITTIUM ITTIBITTIUM BITTIOLUM STYLIDIUM LIROBITTIUM CACOZELIANA FIG. 2. External anatomical characters of five genera of the BiWum-group. Figures to left represent right lateral views of headfoot, showing mantle edge, ciliated gutter, ovipositor and epipodial skirt configuration; figures to left show sole of foot, anterior mucus gland, metapodiai mucus gland (when present) and con- figuration of epipodial skirt. GENERIC REVIEW OF BITTIINAE 273 better understood and a phylogenetic analy- sis can be accomplished. BITTIUM Gf?AY. 1847 Bittium Gray, 1847a (Oct.): 270 (Type species by subsequent designation, Gray, 1847b: Strombiformis reticulatus DaCosta, 1778). Thiele, 1929: 211; Wenz, 1940: 755; Nordsieck, 1968: 68; Houbrick, 1977: 103. Cerithiolum TIberi, 1869: 263 (Type species by original designation, Strombiformis re- ticulatus DaCosXa, 1778). Manobittium Monterosato, 1917: 20 (Type species by monotypy, Cerithium latreillei Payraudeau, 1826, = S. reticulatus). Thiele, 1929: 212. Inobittium Monterosato, 1917: 20 (Type spe- cies by monotypy, Cerithium lacteum Philippi, 1836, = S. reticulatus). Thiele, 1929; 212; Wenz, 1940: 757. Rasbittium Gr?ndel, 1976: 53 (Type species by original designation, Cerithium /aire/V- te/Payraudeau, 1826, = S. reticulatus). Diagnosis Shell small, elongate, with short anterior ca- nal and sculptured with 4-5 spiral cords with many aligned small beads formed where axial riblets are crossed by spirals. Operculum cir- cular, paucispiral with subcentral nucleus. Epi- podial skirt with many small, short papillae. Opercular lobe with small pointed papillae. Well-developed ovipositor comprising parallel glandular ridges and bisected by egg-laying gutter on right side of foot near edge of epi- podial skirt. Osphradium ridge-like, weakly monopectinate, one-half the ctenidial length. Openings to sperm bursa well separated from opening to seminal receptacle. Remarks Bittium Gray, 1847a, was first proposed in manuscript by Leach in 1818 for a classifica- tion of British IVIollusca, and it was subse- quently made available by Gray (1847a). Leach's list referred Bittium and several other diverse genera to Purpuridae and under the 65th entry listed Murex retlculatum, M. tuber- culare, M. adversum, M. elegantlssimum, and M. spencerl, consecutively, under Bit- tium. Besides Bittium reticulatum, the other species listed by Leach represent two gen- era, Triphora Blainville, 1828, and Cerithiop- sis Forbes & Hanley, 1851. Neither a descrip- tion of Bittium nor a type species were given. Three months later, Gray (1847b) cited only Bittium reticulatum (Da Costa, 1778) under Bittium, and this citation is a subsequent des- ignation. (Gray's system is explained in his introduction, pp. 129-130, and the species so listed are to be taken as type designations). The earliest diagnosis of Bittium is that of H. Adams & A. Adams (1854) who besides de- scribing shell characters, noted the opercu- lum, epipodial skirt, and opercular lobe. My original paper on Bittium (Houbrick, 1977) reviewed the nomenclatural history of the genus, and should be consulted for de- tailed information about the confusion and taxonomic problems between Bittium and other taxa of small-shelled cerithioideans. Subsequent to that review, there have been many changes and the synonymy of Bittium originally published (Houbrick (1977: 103) has been modified herein: some taxa have been excluded, and genera not originally in- cluded have been added. A commentary on the present synonymy follows: Cerithiolum is an objective junior synonym of Bittium: both genera share the same type species, Bittium reticulatum. Gr?ndel (1976) regarded Cer- ithidium and Rasbittium Gr?ndel, 1976, as subgenera under Bittium, s.S., but as shown before, Cerithidium is excluded from Bittiinae. Rasbittium is a primary objective synonym of Manobittium as seen in the synonymy above. Manobittium and Rasbittium are considered subjective junior synonyms of Bittium be- cause both share the same type species, Cer- ithium latreillei, which is considered by me and a number of authors to be conspecific or subspecific with Bittium reticulatum (see Ver- duin, 1976). The eastern Atlantic species, Cerithium lacteum, which is the type species of Inobittium, also is considered herein to be conspecific with Bittium reticulatum. Wenz (1940: 757) regarded Inobittium as a syn- onym of Lirobittium, but I see no close resem- blance between the shells of the two. Should Cerithium lacteum be a distinct species, as thought by Verduin (1976), the differences are certainly not of generic weight; conse- quently, Inobittium is regarded as a subjective junior synonym. Discussion The genus Bittium is characterized by a can- cellate, beaded shell sculpture formed by 4-5 dominant spiral cords and numerous axial rib- 274 HOUBRICK lets (Fig. 3A-E), a circular operculum with sub- centric nucleus (Fig. 3F), and by the small papillae along the edge of the epipodial skirt and opercular lobe (Fig. 2). The ovipositor in females is a highly developed, raised glandu- lar lump at the base of the foot near the sole edge, forming a series of parallel, glandular ridges bisected by the deep ciliated egg-laying groove (Fig. 4B, ovp). The ridge-like monopec- tinate osphradium is unusual in having the pectins on its right side. It is half the length of the ctenidium. The openings to the sperm bursa and seminal receptacle in the lateral lamina of the palliai oviduct (Fig. 68, C, osr, osp) are well separated from each other in contrast to most other members of the Bittium- group. The shells of small-sized Cerithium species frequently are erroneously misclassified as BiWum species. Griindel (1976) presented several conchological features that he be- lieved separated the two genera. He stated that Cerithium differs from Bittium in having a more complex aperture, but this is only true for larger Cerithium species; some small spe- cies, such as Cerithium atromarginatum, Cer- ithium egenum, and Cerithium zebrum, have apertures like those of Bittium (Houbrick, 1978). Gr?nde! (1976) further indicated that ontogenetic sculptural development in Cerith- ium begins with a single primary spiral cord that becomes stronger and more prominent, forming a keel that is not integrated with the weaker axial riblets; moreover, there are many fine spiral threads of varying strength. In Bittium, whorl sculpture begins with two spirals that quickly become four primary spiral cords forming a network with sharply defined axial riblets. The so called "definitive" shell characters proposed by Griindel (1976) are unreliable, because the more species that are examined, the more exceptions and ambigu- ities one encounters. Marcus & Marcus (1963) cited the pres- ence of a metapodial mucus gland in Bittium reticulatum, crediting this information to Fret- ter (1948). However, no such gland was ob- served in living or preserved, sectioned spec- imens from the Azores; furthermore. Ponder (in litt.) did not note this structure on speci- mens of Bittium reticulatum from the western coast of Sweden. Fretter's (1948; 628) paper merely cites the presence of this gland in such small gastropods as Bittium, Cerithiop- sis, and Triphora, but as she mentioned only generic names, it is unclear what "Bittium" species she actually observed. All living, observed members of the Bittii- nae appear to be feeders of epiphytic microal- gae, such as diatoms, which occur commonly on sea grasses. Most species occur in large populations and are highly gregarious. Species of the genus Bittium appear to be primarily concentrated in the eastern Atlantic; the Bittium reticulatum complex and species closely related to it are commonly found throughout the Mediterranean, north African, and western European regions, and appear to be adapted to temperate and cold waters. Bittium impendens from the Indo-Pacific, which differs from the Atlantic Bittium species only in lacking a monopectinate osphradium, is herein included under the genus Bittium. If this species truly belongs in Bittium s.S., and if other anatomically unknown Indo-Pacific spe- cies are examined, the geographic distribu- tion of the genus Bittium may be far wider than is now thought. Bittium reticulatum (Da Costa, 1778) (Figs. 3-6) Strombiformis reticulatus Da Costa, 1778: 117, pl. 8, fig. 13. Murex reticulatus (Da Costa). Montagu, 1803: 272. Cerithium latreillei Payraudeau, 1826: 143. Cerithium lacteum Philippi, 1836: 195. Cerithium reticulatum, Risso, 1826; 157; G. B. Sowerby, 1855: pl. 15, fig. 8; Jeffreys, 1867; 258; 1869; pl. 80, fig. 4; 1885; 57. Bittium reticulatum, Watson, 1886; 540; Buc- quoy et al., 1884: 212-215, pl. 25, figs. 3-9; Tryon, 1887: 15?-151, pl. 29, figs. 78-83; Dautzenberg, 1889; 40-41. Description Shell (Fig. 3A-H): Shell elongate, reaching 15 mm in length, comprising 9-10 moderately inflated whorls. Protoconch (Fig. 3G) com- prising two weakly sculptured whorls. Early whorls beginning with two spiral cords and broad subsutural ramp (Fig. 3H). Adult whorls sculptured with 4-5 spiral cords beaded where many small axial riblets cross over them, creating cancellate sculpture. Suture deeply impressed. Body whorl a little under one-third shell length, having weak basal con- striction and small anterior canal weakly re- flexed to left. Body whorl sculptured with five major spiral cords and 5-6 weaker cords on its base. Aperture ovate, a little over one-third shell length, with concave columella having GENERIC REVIEW OF BITTIINAE 275 FIG. 3. Representatives of genus Bittium: A-H, B. reticulatum; l-N, S. impendens. A-C, SEM micrographs of B. reticulatum from Sao Miguel, Azores (USNM 878030), 6 mm length; D, E, S. reticulatum from Tunisia (USNM 754051), 11 mm length; F, SEM micrograph of operculum of B. reticulatum, bar = 0.5 mm; H, SEM micrograph of immature shell of B. reticulatum, bar = 0.5 mm; l-L, SEM micrographs of shell of B. impendens from Honolulu, Hawaii (USNM 857098), 5 mm length; M, SEM micrograph of operculum of B. impendens, bar = 0.5 mm; N, SEM micrograph of protoconch of B. impendens, bar = 150 fim. 276 HOUBRICK slight columellar callus; anterior canal short, shallow; anal canal very small; outer lip rounded, weakly crenulate. Periostracum thin, light tan. Animal (Figs. 4-6): Head-foot of animal pig- mented light yellowish-brown overlain by large dark brown blotches and small white spots. Visceral mass with 8 visceral whorls, comprising mostly digestive gland and over- lying gonads. Ovary white; testis dirty yellow. Stomach about one whorl in length. Kidney large, light tan, about two-thirds whorl in length. Columellar muscle white, broad, short, about one-half length of palliai cavity. Head (Fig. 4A) with elongate, narrow snout (Fig. 4B, sn), flattened dorso-ventrally, expanded at bi- bbed tip, with bright yellow, oval-shaped oral pad at anlero-ventral end (Fig. 4A, C, 1). Cephalic tentacles (Fig. 4A, t) elongate, nar- row, with broad peduncular bases each with large dark eye. Foot narrow, elongate, cres- cent shaped anteriorly. Deep transverse slit (Fig. 4C, amg) between epipodial lips marks entrance to large ovate anterior mucus gland extending via central duct deep into anterior foot. Epipodium separated from lower foot and densely ciliated sole by deep, laterally placed groove (Fig. 4B, epg) forming broad epipodial skirt (Fig. 4B, C, eps) extending posteriorly on each side of foot from corners of anterior epipodial lips of anterior mucus gland around entire foot base, joining behind and below opercular lobe. Lateral epipodial skirt scalloped along edges of each side of median and posterior parts of epipodium, having small papillae (Fig. 48, C, ep); epipo- dial skirt forming long opercular lobe (Fig. 4B, C, opi). Sole of foot (Fig. 4C, s) indistinctly divided into two parallel axial parts, forming anterior longitudinal fold. No metapodial mu- cus gland. Operculum (Fig. 3F) corneous, tan, circular, paucispiral with subcentral nu- cleus and with thin, transparant border. Cili- ated gutter (Fig. 4B, C, eg) emerging from right side of mantle cavity (Fig. 4C, ex) and running down right side of foot; ciliated gutter leads to large glandular ovipositor (Fig. 4B, C, ovp) and egg-laying pit at base of epipodium in females. Ovipositor oval-shaped, com- prised of glandular, transparant white tissue formed into many parallel pleats divided transversely by deep central slit. Mantle bi- lobed at edge, having smooth outer lobe and inner lobe with many small papillae, becom- ing smooth ventrally. Mantle papillae (Fig. 4B, C, mp) slender, darkly pigmented, each with white spot. Mantle edge thickened at inhalant (Fig. 4C, inh) and exhalant siphons. Palliai Cavity: Palliai cavity deep, comprising about two whorls. Osphradium olive colored, ridge-like, pectinate on right side only, bor- dered on each side by narrow ciliated strip. Osphradium wide, about one-half ctenidial length, beginning close behind inhalant si- phon and extending length of ctenidium. Ctenidium bluish-gray, comprising numerous finger-like, triangular filaments with narrow bases. Hypobranchial gland narrow, glandu- lar comprising several kinds of large gland cells that stain dark blue. Rectal tube dis- tended, filled with elongate, ovoid-shaped fe- cal pellets. Palliai gonoducts open, beginning behind mantle edge and extending posteriorly as far as kidney. Reno-pericardial System: Kidney large, about two-thirds whort in length, beginning at ante- rior end of style sac, extending anteriorly well into mantle cavity roof, lying over one-third of posterior palliai gonoduct. Kidney with simple kidney opening, but no renopericardial duct. Pericardium typically monotocardian, lying ad- jacent to posterior wall of mantle cavity. Alimentary System: Mouth (Fig. 4A, m) lying antero-ventrally on snout, opening into oral cavity between two semicircular lips (Fig. 4A, C, 1). Buccal mass (Fig. 4D, bm) relatively small, about one-third snout length, loosely attached to snout wall by numerous thin mus- cle strands. Jaw tan, semicircular, comprised of cuticular cones and lying on either side of entrance to anterior buccal cavity. Radular ribbon (Fig. 5A; Table 2) folded beneath buc- cal mass and radula sac emerging behind it. Rachidian tooth (Fig. 5C) with dorso-ventrally compressed basal plate with concave sides rounded base and with V-shaped base but- tressed on each side with a basal lateral ex- tension; rachidian broader above than below, having cutting edge with slightly concave top, and comprising large, spade-shaped central cusp flanked on each side by 2-3 small, pointed denticles. Lateral tooth (Fig. 5B) with broad basal plate comprising long, ventrally extending, central pillar having small pustule on its face, and with moderately long lateral extension; cutting edge comprising very large spade-shaped cusp with one inner denticle and 3-6 outer denticles. Marginal teeth (Fig. 5A) curved, elongate, with broad, swollen shafts, narrowing and becoming spatulate at tips; inner marginal tooth with tip having long GENERIC REVIEW OF BITTIINAE 277 FIG. 4. Anatomical representations of Bittium reticulatum. A, head and snout; B, lateral view of headfoot; C, fiead and sole of foot; D, anterior alimentary system exposed by dorsal longitudinal cut through wall of buccal cavity, aes = anterior esophagus; amg = anterior mucus gland; beg = subesophageal gland; bg = buccal ganglion; bm = buccal mass; c = ciliated strip; eg = ciliated gutter; eg = esophageal gland; ep = epipodial papilla; epg = epipodial groove; eps = epipodial skirl; ex = exhalant siphon; inh = inhalant siphon; I = lip; leg = left cerebral ganglion; Ipg = left pleural ganglion; Isg = left salivary gland; m = mouth; mp = mantle papilla; op = operculum; opi = opercular lobe; ovp = ovipositor; pes = posterior esophagus; reg = right cerebral ganglion; rpg = right pleural ganglion; rsg = right salivary gland; s = sole; seg = supraesophageal ganglion; sn = snout; t = tentacle. 278 HOUBRICK FIG. 5. Scanning electron micrographs of radula of Bittium reticulatum from Sao Miguel, Azores (USNM 878030). A, half row with marginal teeth folded back, bar = 19 ^m\ B, rachidian and lateral teeth, bar = 15 |i,m; C, detail of rachidian teeth, bar = 4 jxm. central cusp, 3-4 inner denticles, 4 outer denticles; outer marginal tooth same, but lacking outer denticles. Salivary glands (Fig. 4D, rsg, Isg) comprising pair of narrow, un- coiled, shiny tubes, beginning behind nerve ring, extending through it anteriorly, opening into far anterior portion of buccal cavity. Buc- cal cavity opening and enlarging immediately behind nerve ring, having pair of prominent dorsal folds and smaller pair of smaller ventral folds. Interior mid-esophageal w/alls highly folded, forming large, olive-brown esophageal gland (Fig. 4D, eg). Internal epithelium of esophageal gland (Fig. 7A, B, eg) forming nu- merous transverse folds or lamellae, staining dark blue with f\/lethylene blue. Posterior esophagus (Fig. 4D, pes) narrow and straight, running on top of columeilar muscle, entering into left side of stomach. Stomach large, com- prising about one whorl of visceral mass, in- cluding style sac. Esophageal opening into median ventral part of stomach floor. Large GENERIC REVIEW OF BITTIINAE 279 sorting field with many fine folds adjacent to right side of esophageal opening. Minor typhlosole bordering right side of esophageal opening. Large central elevated pad in center of stonnach adjacent to single duct to diges- tive gland lying short distance below esoph- ageal opening. Digestive gland comprising single brown lobe consisting of digestive cells and secretory cells with dark brown granules. Gastric shield on right side of stomach having cuticular lining with protruding, toothed edge. Depressed epithelial pocket on floor of stom- ach adjacent to posterior part of gastric shield. Style sac short, about one-third the stomach length, nearly spherical, and con- taining crystalline style. Style sac adjacent to but separate from intestine opening, except for limited connection where both enter stom- ach. Anterior part of stomach with many par- allel ciliated folds and closed off from style sac by major typhlosole. Internal intestinal walls with many fine folds where exiting stom- ach. Intestine curves around style sac, turns to right, and runs straight forward. Rectum with thin muscular wall, terminating in anal- bearing papilla. Nervous System: Nervous system epiath- roid, dialyneurous. Nerve ring comprised of large ganglia. Pleural ganglia (Fig. 4D, rpg, Ipg) close to cerebral ganglia (Fig. 4D, rcg, leg). Cerebral connective equalling length of cerebral ganglion. Buccal ganglia (Fig. 4D, bg) small, lying at posterior edge of buccal mass. Subesophageal ganglion (Fig. 40, beg) very close to left pleural ganglion (Fig. 4D, Ipg). Supraesophageal connective mod- erately long, about twice length of right pleural ganglion; dialyneury between left palliai nerve and nerve emerging from supraesophageal ganglion (Fig. 4D, seg). Visceral ganglion lo- cated in floor of posterior mantle cavity. Reproductive System: Testis creamy yellow, overlying dark brown digestive gland, extend- ing anteriorly about five whorls, ending one- half whorl before stomach. Testicular ducts on inner side of visceral coil, joining to form spermatic duct, enlarging anteriorly, becom- ing seminal vesicle and containing two kinds of spermatozoa; euspermatozoan with single long flagellum and paraspermatozoan with [four ?] flagellae. Males aphallate. Male palliai gonoduct (Fig. 6A) open, comprising two thin walled laminae (Fig. 6A, 11, ml) with thicker transverse glandular folds at their attached bases bordering gonaductal groove (Fig. 6A, gd). Posterior half of male gonoduct thick. glandular, comprising prostate gland (Fig. 6A, pg). Anterior half of male gonoduct glandular, not as thick, putative spermatophore-forming organ (Fig. 6A, so). Ovary opaque white, thin-walled, overlying digestive gland, extending anteriorly, ending about one-half whorl before stomach. Coelo- mic oviduct (Fig. 68, C, cod) short tube, highly ciliated within, beginning anterior to stomach with duct wall lying against pericardium (no connection), ending at posterior mantle cavity where circular sphincter muscle separates it from palliai oviduct. Female palliai oviduct (Fig. 6B, C) large, comprising two laminae, enlarged and glandular at their bases, at- tached basally to each other and to mantle floor, forming ciliated oviductal groove (Fig. 68, C, ovg). Posterior end of palliai oviduct closed. Medial, free lamina with wide anterior ciliated sperm gutter (Fig. 68, C, sg) along its edge leading to two, well-separated, pocket- like openings. First opening (Fig. 68, C, osp) leading into large, deep bursa having smooth inner epithelium and containing large num- bers of non-directed spermatozoa (Fig. 7C, D, sp); ciliated gutter continuing posteriorly to open (Fig. 7C, osr) into pouch-like, muscular seminal receptacle (Fig. 6C, B sr; 8C, D, sr) containing oriented euspermatozoa with heads embedded in receptacle walls. Lateral lamina attached to palliai wall, having anterior ciliated tract comprising many parallel elon- gate, fine ciliated folds (Fig. 68, C, ctr; 7A, B, ctr) running posterior to open into thin-walled tube leading into posterior pouch-like bursa having highly vacuolated epithelium and func- tioning as spermatophore bursa (Fig. 6B, C, sb). Ciliated tract and folds opening to semi- nal receptacle on lateral lamina located oppo- site sperm gutter and opening to seminal re- ceptacle of medial lamina, both edges interdigitating to form closed system. Poste- rior half of glandular portion of both laminae opaque white color, comprising albumen gland (Fig. 68, C, ag; 7C, D, ag); anterior half dirty white, comprising capsule gland (Fig. 68, C, eg; 7A, 8, eg). Spawn comprising thin gelatinous string (about 25 mm length, uncoiled) tightly coiled clockwise or irregularly folded on itself and attached to substrate. Jelly string containing many small opaque eggs (0.65 |a,m diameter) each within thin, transparent hyaline capsule (110 ^.m diameter). Entire spawn mass con- tains about 800 eggs. Free swimming bilobed planktotrophic veliger larval stage present. Larval shell ranging from 170-330 ^im, de- 280 HOUBRICK cod osr ?^'XJv^ ml so II 0.2 mm Ictr ovg II . osb B 0.2mm ml osp cod FIG. 6. Representation of palliai gonoducis of Bittium reticulatum. A, male palliai gonoduct, showing section through mid-duct beneath, represented by dotted line; B, palliai oviduct showing three cross sections of duct represented by dotted arrows and sections to right; C, reconstruction of palliai oviduct showing configuration of ducts and glands (anterior to right), ag = albumen gland; ant = anterior; eg = capsule gland; cod = coelomic oviduct; ctr = ciliated ridge tract; gd = gonaductal groove; II = lateral lamina; ml = medial lamina; osb = opening to spermatophore bursa; osp = opening to sperm bursa; osr = opening to seminal receptacle; ovg = oviductal groove; po = closed portion of palliai oviduct; sb = spermatophore bursa; sg = sperm gutter; sp = sperm bursa; sr = seminal receptacle; so = spermatophore-forming organ. pending upon age. Larval shell wWh rounded, nearly smooth whorls having thin spiral thread forming weak keel and with deep sinusigeral notch (Thorson, 1946; 192, fig. 109). Discussion The status of the many specific and sub- specific names comprising the Bittium reticu- GENERIC REVIEW OF BITTIINAE 281 FIG. 7. Successive sections, anterior to posterior, through palliai oviduct of Bittium reticulatum. A, anterior of palliai oviduct showing relationship of mantle cavity organs to oviduct, bar = 0.25 mm; B, mid-section shov^ing ciliated ridge tract and opening to sperm bursa, bar = 0.25 mm; C, section through enlarged sperm bursa in posterior palliai oviduct, bar = 0.25 mm; D, section through closed posterior of palliai oviduct, bar = 0.25 mm. ag = albumin gland; eg = capsule gland; ct = ctenidium; ctr = ciliated ridge tract; eg = esophageal gland; hg = hypobranchial gland; os = osphradium; osp = opening to sperm bursa; ovg = oviductal groove; r = rectum; sb = spermatophore bursa; sg = sperm gutter; sp = sperm bursa; sr = seminal receptacle. latum complex is controversial (Verduin, 1976). It is not my intention to address alpha- level problems in this generic review, but the Azorean population used for the anatomical study herein Is considered by some as a sub- species or a closely related species of the Bittium reticulatum complex. Bittium reticula- tum is exceedingly variable in shell sculpture throughout its range (compare Figs. 2A, C, D), but this is not unusual among cerithioide- 282 HOUBRICK ans. The palliai oviduct described by Johans- son (1947) and notes and sketches made by Ponder (Ponder, in litt.) on the anatomy of specimens from western Sweden agree sub- stantially with my observations of Azorian specimens. For the purposes of this study, the Bittium reticulatum complex is regarded in the broad sense {sensu lato), as a single spe- cies. The epipodial skirt, characteristic of mem- bers of the ?/fi/um-group, forms a highly cili- ated lateral groove where it overhangs the foot, and carries detrital particles posteriorly to the back of the foot where they are dis- carded. The posterior roof of the palliai cavity is covered by the anterior extension of the renal organ, which overlays the posterior palliai gonoduct. The renal organ opens via a mus- cular sphincter, the renal opening, into the posterior palliai cavity. The ridge-like osphradium of Bittium retic- ulatum is unusual in being pectinate on its right side. Although these pectins are small, they are clearly visible and very unlike simple nonpectinate osphradia of closely related taxa. The rachidian tooth of the radula of Bittium reticulatum is similar to those of members of other genera in the group, but unlike that of Cacozeliana (see below). Table 2 gives the comparative dentition of the radular teeth. Bittium reticulatum has three sperm stor- age spaces, two connected to the ciliated groove of the non-glandular portion of the me- dial free lamina, and one in the posterior part of the non-glandular attached lateral lamina (Fig. 6B, 11 ). It is not entirely clear how these three bursae function. Of the two bursae in the medial lamina, the smaller one is clearly the seminal receptacle, because oriented eu- spermatozoa are found in it, exclusively (Fig. 7C, D, sr). The larger bursa (Fig. 6B, sp) con- tains considerable numbers of unoriented sperm, and much nondescript material (pre- sumably disintegrating paraspermatozoa and degenerating spermatophores), although some euspermatozoa occur with heads ori- ented on the inner wall epithelium, especially near the opening to the sperm gutter (Fig. 7D). Although this large bursa in the medial lamina contains spermatophores in most cer- ithiids, this is not the case in members of the Bittium-group, where it appears to function as a sperm storage and ingesting area. It is in- ferred that the pouch in the posterior of the lateral lamina (Fig. 6C, sb, Fig. 7C, D, sb) functions as a spermatophore bursa in Bittium reticulatum and probably in most other mem- bers of the Bittium-group, because Marcus & Marcus (1963) found spermatophores in this structure in the western Atlantic Bittiolum var- ium. I was unsuccessful in finding spermato- phores in either structure in specimens of Bittiolum varium from Florida. A new genus from the Indo-Pacific, Ittibittium, described herein, deviates from the typical palliai ovi- duct layout in lacking the spermatophore bursa in the lateral lamina and in having the albumen gland protrude posteriorly beyond the back of the palliai cavity Into the visceral coil. The spawn of Bittium reticulatum was first deschbed and figured by Meyer & M?bius (1872), and the spawn and larvae described by Lebour (1937) and Graham (1988). Spawn, larvae, veliger, protoconchs, and ju- venile shells of this species were described and well illustrated by Thorson (1946: 192, fig. 109). Other depictions of the larval shell of this species are those of Fretter & Pilkington (1970: 10-11, fig. 6) and Richter & Thorson (1975: pi. 3, figs. 16-17). According to Gra- ham (1988), British Bittium reticulatum is a summer breeder and attaches its spawn to shells, stones or weeds. Spawn comprises a cylindrical ribbon about 3 mm in diameter, having a total length of 25 mm, and coiled in tight spirals. A spawn mass contains about 1000 eggs, which develop to veliger larvae. The geographic range of the Bittium reticu- latum complex is broad, comprising western Europe, the Azores, North Africa, and the Mediterranean. Bittium impendens (Hedley, 1899) (Fig. 3, l-N) Cerithium impendens Hedley, 1899: 434- 435, fig. 23 (Holotype: AMS 05944; type locality: Funafuti Atoll, Ellice Islands); Kay, 1979: 118, 120, fig. 45A. Description Shell: (Fig. 31-N). Shell short, stout, with wide base, reaching 7 mm length and com- prising 8-9 convex whorls. Protoconch (Fig. 3N) comprising 2.5 whorls; protoconch 1 smooth; protoconch 2 sculptured with thin central, spiral keel and weak presutural spiral thread; lower part of each whorl with micro- scopic pustules. Whorls slightly pendant abapically, constricted at suture. Adult shell sculptured with 3-4 major spiral cords inter- GENERIC REVIEW OF BITTIINAE 283 spersed with spiral threads. Spiral cords weakly beaded and beads aligned to form ax- ial riblets. Suture well defined. Weak varices randomly distributed. Body whorl very broad, about one-half the shell length, with promi- nent wide, dorsal varix (Fig. 3J, L); body whorl sculptured with about 14 spiral cords and strongly constricted at base. Aperture a little over twice shell length, broadly ovate, with short, wide, shallow anterior canal and smooth outer lip extending widely at shell base (Fig. 31). Animal: Headfoot pinkish white, blotched with brown, covered with white spots and with chestnut stripes. Kidney bright pink. Right side of foot in females with ciliated gutter end- ing in small ovipositor at edge of lateral groove. Epipodial skirl having very small pus- tules or protuberances along lateral edges on each side of foot; opercular lobe scalloped and pointed at end. Sole of foot pink, without metapodial mucus gland. Mantle edge fringed dorsally with papillae; underside of inhalant siphon with three large papillae. Marginal teeth of radula having three inner denticles. Osphradium a thin brown ridge, non-pecti- nate. Openings to sperm pouch and seminal receptacle in medial lamina close to each other, situated within common aperture at end of sperm gutter in edge of anterior third of medial lamina adjacent to opening of sper- matophore bursa of lateral lamina. No ciliated tract leading to spermatophore bursa. Discussion Examination of the type lot (holotype and 7 paratypes) of Cerithium impendens confirms that the Hawaiian specimens studied herein are conspecific with this taxon. This species has not been cited frequently in the literature. The assignment herein of Bittium impen- dens to the genus Bittium is made with some doubt. The shell morphology of this wide- spread Indo-Pacific species is quite different from that of the type species of Bittium, Bit- tium reticulatum (compare Fig. 3A-E and 31-L), and unlike the shells of other eastern Atlantic Bittium species. In addition, the os- phradium is ridge-like rather than mono- pectinate, and there does not appear to be a ciliated tract associated with the spermato- phore bursa on the lateral lamina. Instead, the opening to the spermatophore bursa is adja- cent to the two openings of the bursae in the medial lamina. The radula of Bittium Impen- dens is very similar to that of Bittium reticula- tum except that the marginal teeth have fewer outer and inner denticles. Aside from these differences, the animal shares most of the an- atomical features of Bittium reticulatum. Al- though an argument could be made that this species represents yet another new genus, I have conservatively placed Bittium impen- dens under Bittium, s.s, with a query, be- cause it does have many characters in com- mon with the type species of Bittium. The shell of Bittium impendens differs from other SMum-group genera by its fir-tree out- line and wide body whorl with prominent dor- sal varix (Fig. 31-L). The protoconch (Fig. 3N) is smooth except for a thin spiral thread and a deep sinusigeral notch, indicative of a plank- tonic larval phase. Judging from specimens from other regions that appear to be concho- logically conspecific, this species has a wide Indo-Pacific distribution, occurring from cen- tral Pacific islands throughout the Indo-West- Pacific to east Africa. miBITTIUM, New Genus Diagnosis Shell small, reaching 6 mm length, with in- flated whorls and dominant spiral sculpture of 4-5 cords. Protoconch with depressed, con- cave apex, broad sutural ramp, sculptured with minute axial striae and two strong spiral cords. Operculum ovate, paucispiral with ec- centric nucleus. Each side of propodium with elongate papilla. Epipodial skirt laterally fringed with slender papillae. Large opercular lobe having elongate papillae. No ovipositor in females. Sole of foot with long, central lon- gitudinal slit marking entrance into large metapodial mucus gland. Osphradium weakly bipectinate. Albumen gland extending past posterior of palliai cavity into visceral coil. No spermatophore bursa in lateral lamina of pal- liai oviduct. Spawn compnsing short gelati- nous tube. Type Species: Bittium parcum Gould, 1861. Etymology: A compound of "itti," American vernacular prefex for very small, and Bittium. Remarks This genus is perhaps one of the most dis- tinctive of the Bittium group, in terms of its unusual protoconch and anatomical features. 284 HOUBRICK The proloconch with depressed apex and broad sutural ramp (Fig. 81) is unique among the Bittium-group. The distinctive propodial and epipodial papillae, well-developed epipo- dial skirt, and long metapodial mucus gland are conspicuous autapomorphiic characters in living specimens (Fig. 2). The lack of a spermatophore bursa in the lateral lamina of the palliai oviduct and the protrusion of the albumen gland through the posterior palliai cavity into the visceral coil are highly unusual autapomorphies, and set Ittibittium, gen. n., apart from the rest of the Bittiinae. The place- ment of the spermatophore bursa in the lat- eral lamina is one of the synapomorphous character used in this review to define the subfamily Bittiinae; therefore, it is noteworthy that Ittibittium, gen. n., has lost this feature. The spawn mass of Ittibittium, gen. n., is also unusual in being a simple, short tube. In some museum collections, Bittium par- cum and species similar to it are incorrectly assigned to Bittinella Dall, 1924, a genus based on Bittium hiloense Pilsbry & Vanatta, 1908, which has been shown to be a rissoid of the genus Isselia (Ponder, 1985: 95; Kay, 1979:80). ittibittium parcum (Gould, 1861) (Figs. 8-11) Bittium parcum Gould, 1861: 387 (Lectotype, R. Johnson, 1964, USNN/I 2040; type lo- cality Okinawa, Ryukyu Islands); G. B. Sowerby, 1866: pi. 18, fig. 125; Tryon, 1887: 155, pi. 30, fig. 20; R. Johnson, 1964: 122, pi. 12, fig 14; Kay, 1979: 120, figs. 22D, 45D, E. Cerittiium tiawaiensis Pilsbry & Vanatta, 1905: 576 (Holotype ANSP; type locality: Hilo, Hawaii). Description Shell (Fig. 8): Shell small, pupale-elongate, comprising about 8 inflated, angulate whorls and reaching 5.8 mm length. Protoconch (Fig. 8F-I) compnsing two concave whorls, con- cavely flattened apex, very broad sutural ramp sculptured with minute axial striae (Fig. 8F); protoconch whorls sculptured with two strong, keel-like spiral cords, with central spi- ral cord becoming dominant one. Early whorls sharply angulate (Fig. 81); first post-larval whorl with keel-like median spiral cord; sec- ond whorl with another spiral cord above keel and third whorl having 3 spiral cords above keel. Adult whorls angulate, sculptured with keel-like median cord, 7-8 minor spiral cords, each cord abapically overlapped by succes- sive one. Eight to nine weak to strong axial ribs occasionally on whorls, especially on up- per ones (Fig. 8J). Varices randomly placed. Suture moderately impressed. Body whorl (Fig. 8L) slightly constricted at base, compris- ing a little less than half shell length, sculp- tured with 15-19 weak flattened spiral cords, occasional weak axial ribs and with broad varix. Aperture about one-third shell length, ovate with smooth outer lip and short broad anterior canal. Slight columellar callus present. Periostracum thin, nearly transpar- ent. Animal: Animal pigmentation highly variable, ranging from greenish-yellow to pink and brown and covered with white blotches. Cephalic tentacles wide at bases, elongate, twice snout length. Snout elongate, narrow, bilobed at tip. Operculum (Fig. 8K) thin, cor- neous, tan, circular-ovate, paucispiral with subcentral nucleus. Anterior part of foot cres- cent-shaped, cowl-like, having single long pa- pilla on each side (Fig. 2). Narrow transverse slit at edge of propodium leading into large, spherical anterior mucus gland, staining deep purple in toluidine blue. Lateral epipodial skirt with about 10 small, slender papillae along edges (Fig. 2) on each side of foot, extending posteriorly to large opercular lobe having long papillae along its edges; papillae show through edges of opercular border. Sole of elongate, narrow foot having deep, centrally placed, narrow longitudinal slit (Fig. 2) begin- ning behind anterior mucus gland slit (Fig. 2) and extending posteriorly to back of foot; slit leading by way of ciliated duct into deep, mas- sive, metapodial mucus gland, staining deep purple in toluidine blue. Males with ciliated sthp on right side of foot, emerging from right side of mantle cavity and extending down to edge of sole. Ciliated gutter on right side of foot in females deep, running down side of foot and extending through lateral epipodial groove (Fig. 2). No ovipositor present. Mantle edge dorsally fringed with many small papil- lae. Palliai Cavity: Osphradium a little less long than ctenidium, broad, about one-third ctenid- ial width, dark brown, weakly bipectinate with small pectins on each side but unconnected dorsally; osphradium becoming monopecti- nate at inhalant siphon. Ctenidium narrow, extending length of palliai cavity, comprising GENERIC REVIEW OF BITTIINAE 285 FIG. 8. SEM micrographs of IWbiWum parcum from Honolulu, Hawaii (USNM 857100). A, B, apertural and lateral views of shell, 3.6 mm length; C-E, apertural, lateral and dorsal views of shell, 3.6 mm length; F, newly hatched larval shell showing protoconch and details of whorl sculpture, bar = 63 (j,m; G, H, embryonic shells removed from eg capsule, bar = 23 ^jLm; I, larval and early whorls of shell, bar = 0.4 mm; J, shell with strong axial ribs, 5.3 mm length; K, operculum, bar = 0.2 mm; L, detail of penultimate and body whorl, showing details of sculpture and aperture, bar = 0.6 mm; M, apertural view of shell, 3.6 mm length. 286 HOUBRICK FIG. 9. SEM micrographs of radula of IWbittium parcum from Honolulu, Hawaii (USNM 857100). A, middle of radular ribbon with right marginal teeth folded back, bar = 30 n,m; B, detail of rachidian and lateral teeth, bar = 8 ^.m. long, finger-like, triangular filaments. Hypo- branchial gland partially overlaying rectunn, well developed, composed of several large, dark-staining glandular cells. Reno-pericardial System: Pericardium lying adjacent to posterior palliai wall. Kidney large, extending from anterior of style sac forward, into roof of posterior palliai cavity. Alimentary System: Snout tip and lips of mouth yellow. Buccal mass large, about two- thirds snout length. Radula (Fig. 9A) short, about one-tenth shell length. Rachidian tooth having weak hour-glass shape and cutting edge with large central cusp flanked by 2 den- ticles on each side. Lateral tooth (Fig. 98) having cutting edge with large pointed cusp, one inner denticle, 3-4 outer denticles. Inner marginal tooth with 2 inner denticles, large elongate major cusp and 3 outer denticles; outer marginal tooth with 5 inner denticles. Salivary glands paired, comprising tangled mass behind nerve ring, extending through it anteriorly as slender tubes. Esophagus be- coming wide behind nerve ring, developing lateral glandular pouches with many small transverse internal folds, comprising short esophageal gland. Stomach large, about one whorl in length, having single opening to di- gestive gland, central raised pad, gastric shield, short crystalline style and style sac, about two-thirds the stomach length. Intestine leaving stomach looping dorsally and across anterior style sac, turning sharply, running an- teriorly, adjacent to right side of kidney and albumen gland. Rectum slightly wavy, wide, containing large ovoid fecal pellets. Nervous System: Cerebral ganglia very large, twice size of pleural ganglia. Sube- sophageal ganglion very close to left pleural ganglion. Supraesophageal ganglion sepa- rated from right pleural ganglion by connec- tive two-thirds ganglion length. Reproductive System: Testis white, overlay- ing brown digestive gland. Males aphallate with open palliai gonoducts. Palliai oviduct open, with large albumen gland extending through posterior of mantle cavity mantle cav- ity, protruding into visceral coil. Albumen gland staining cream-green in toluidine blue. Capsule gland very large, swollen, staining dark blue In toluidine blue. Large spermato- phore bursa in posterior medial lamina. No ciliated ridge tract or seminal receptacle in lat- eral lamina. Spawn mass comprising wide ge- latinous tube covered with thin membrane forming compact, short tube about 2 mm long, and 1.2 mm wide, containing large opaque, compacted eggs each 0.2 mm in diameter. Eggs arranged in short jelly tube about 3-4 GENERIC REVIEW OF BITTIINAE 287 deep. Development direct with young snails tiatching from eggs. Discussion "Bittium" parcum has not been cited com- monly in the literature, and due to great inter- specific variability in shell sculpture and color, is frequently misclassified or unidentified in museum collections. Shell shape can vary from slender, elongate (Fig. 8J) to shorter, more inflated (Fig. 8C-E), and shell sculpture is highly variable: the axial ribs seen in some specimens may be entirely lacking in others. The protoconch with its flattened apex, broad sutural ramp and concave whorls is highly distinctive and unusual (Fig. 8F-H). However, Ittibittium parcum is readily distinguished from by several external anatomical features: (1) the epipodial skirt and opercular lobe are fringed with well-developed papillae; (2) a pair of long epithelial extensions (papillae) of the front of the foot (propodium); (3) the longitu- dinal slit marking the entrance to the metapo- dial mucus gland is very long. Ittibittium par- cum has an unusual palliai oviduct in that the albumen gland projects posteriorly past the posterior end of the mantle cavity into the vis- ceral coil, and there is no seminal receptacle in the lateral lamina of the pallia! oviduct. Living snails are quick, active crawlers, and even when removed from their shells showed a great deal of movement. The operculum in this species tends to be more ovate than circular; in most other spe- cies of the Bittium-group, the operculum is cir- cular. The opercular lobe papillae show through the transparent edges of the opercu- lum. This species undergoes direct develop- ment. The embryos pass through a veliger stage and hatch out as juvenile snails after losing the velar lobes. Direct development, while also occurring in Stylidium, is not the common mode of development among mem- bers of the Bittium-group. The comparatively large eggs of Ittibittium parcum are each en- closed within individual hyaline capsules about 0.2 mm diameter, and the egg capsules are stacked within a short, wide gelatinous tube and deposited on the substrate in an ir- regular mass. Here they undergo develop- ment, passing through a modified veliger stage and producing a well-developed embry- onic shell (Fig. 8F-H), after which they emerge as small snails. Ittibittium parcum is common in shallow wa- ter throughout the Hawaiian chain, and also occurs in French Polynesia (Naim, 1982) where it is very abundant in some localities. Naim (1982) found that this species repre- sented 89% of the molluscan fauna associ- ated with algae in Tiahura Lagoon in French Polynesia. A species from Western Australia, very similar to the type species, recently has been described in great detail (Ponder, in press), and appears to be closely related to Ittibittium parcum. BITTIOLUM COSSMANN, 1906 Bittiolum Cossmann, 1906: 139. (Type spe- cies by original designation: Bittium pod- agrinum Dall, 1892). Wenz, 1940: 755; Olsson & Harbison, 1953: 289-290. Diagnosis Shell small, turreted, stout, sculptured with 4 spiral cords and many axial ribs, and occa- sional weak varices. Protoconch with one spi- ral lira. Whorls presuturally constricted, body whorl elongate, narrow at aperture and con- stricted at base, having less width than pen- ultimate whorl. Operculum ovoid-circular, paucispiral and with subcentral nucleus. An- terior canal weakly defined, short. Mantle edge smooth, epipodial skirt scalloped. Foot elongated anteriorly and having median lon- gitudinal slit in posterior part of sole, leading into large metapodial mucus gland. Ovipositor small. Osphradium bipectinate, wide, one- third ctenidial length. Nervous system with right zygoneury and with short supraesoph- ageal connective. Remarks Bittiolum species have small shells (Table 3) and are distinctive in having the body whorl elongated and constricted basally so that the aperture width is less than that of the penul- timate whorl. The smooth mantle edge, nar- row elongate anterior foot, right zygoneury and short supraesophageal connective are autoapomorphous characters of this genus. The type species of this genus is a Neo- gene fossil from Florida that has a shell mor- phology very similar to that of living Bittiolum varium and Bittiolum alternatum. As the fossil species occurs in mid- to late-Neogene strata, and in the same geographic area as Recent 288 HOUBRICK Bittiolum varium, it is not unreasonable to in- fer that the two species belong to the same clade, and the living species is considered to be congeneric with Bittium podagrinum. Cossmann (1906: 140) pointed out that Bitti- olum varium (Pfeiffer) (cited as Ceritttium) oc- curred from the Pleistocene of Florida and ex- tended into the Recent. He further noted the superficial resemblance of Bittiolum varium to some fossils of Aneurychilus Cossmann, 1889, which he placed in the Diastomatidae (as Diastomidae, Cossmann, 1906: 174). Dall (1889) was the first author to confuse American members of Bittiolum with the ge- nus Diastoma Deshayes, 1850, when he re- ferred Bittiolum varium to that genus. Abbott (1974), probably following this cue, later re- ferred western Atlantic species of Bittium, s.l., to Diastoma Deshayes, 1850, but this subse- quently has been shown to be incorrect (Houbnck, 1977: 102, 1981b), as the latter genus belongs to the Diastomatidae Coss- mann, 1894, a totally different lineage repre- sented by individuals of much larger size and different anatomy that are not closely related to the Bittium-group (Houbrick, 1981b). The anatomy of "Bittium" alternatum, from the northeastern coast of North America, is identical to that of its southeastern, Carib- bean Province congener, Bittiolum varium. Thus, these two species and probably all other American western Atlantic species be- long in the genus Bittiolum, which is also rep- resented by several eastern Pacific species, such as Bittiolum fastigiatum (Carpenter, 1864). Because the two Bittiolum representatives studied, B. varium and S. alternatum, are so alike, they are treated jointly in the section below. Bittiolum varium (Pfeiffer, 1840) (Figs. 10-11) Cerithium varium Pfeiffer, 1840: 256. Cerithium columellare Orbigny, 1842: pi. 23, figs. 13-15; 1845: 244 (In part; syntypes Bf^NH). Cerithium gibberulum C. B. Adams, 1845; 5 (Lectotype MCZ 186078, type locality Ja- maica). Bittium varium (Pfeiffer). Tryon, 1887:152, pi. 29, fig. 86; Perry, 1940: 134, pi. 28, fig. 202. Cerithium (Bittium) gibberulum (C. B. Ad- ams). Kobelt, 1898: 245-246, pi. 43, fig. 1. Diastoma varium (Pfeiffer). Abbott, 1974: 107, fig. 1037. Description Shell (Fig. 10): Shell turreted, pendent- shaped, comprising about 10 flat-sided whorls and reaching 7 mm length. Protoconch (Fig. 101) comprising 2.5 whorls; protoconch 1 smooth, protoconch 2 with central keel-like spiral lira and microscopic pustules on abapi- cal part of whorl. Early whorls (Fig. 10H) with two weak spiral lirae, and sculptured with dominant suprasutural spiral cord and two weaker spiral cords above it, and with weak axial hbs. Adult whorls sculptured with 4 spiral cords and 14 strong axial ribs forming small beads at crossover points and producing can- cellate pattern. Body whorl elongate, more than one-third shell length, constricted at ap- erture and more at siphon; body whorl sculp- tured with about 10 flattened spiral cords and 14 weak axial ribs. Aperture ovate, con- stricted, not as wide as width of body whorl, narrowing posteriorly and having short, dis- tinct siphonal canal. Columella concave with slight callus. Outer lip of aperture smooth, rounded, thin and pendant, extending beyond siphonal canal. Periostracum thin, tan. Animal: Snout, cephalic tentacles, and neck slender, extremely long and extensible. Snout bilobed at tip. Foot narrow, extremely elon- gate anteriorly, three times snout length, and with crescent-shaped propodium (Fig. 2). Deep crescentic transverse slit formed by two lips in anterior foot and leading via a central duct into large anterior mucus gland (Fig. 11 A, amg). Corners of anterior pedal lips ex- tending laterally and posteriorly forming uncil- iated undulating epipodial skirt (Fig. 11A-B, es) delineating lateral groove between epipo- dium and sole; epipodial skirt weakly scal- loped posteriorly (Fig. 2), forming lanceolate opercular lobe, scalloped around edges. Cili- ated gutter (Fig. 11B, eg) in both sexes emerging from floor of right side of palliai cav- ity, running down right side of foot leading into epipodial groove. Ciliated gutter terminafing in small glandular ovipositor (Fig. 11B, ovp) at edge of foot in females. Posterior third of sole with median longitudinal slit leading into mas- sive mesopodial mucus gland (Fig. 11 A, mmg), extending deeply into head foot up to nerve ring and cephalic hemocoel. Opercu- lum (Fig. 10F, G) corneous, light tan, circular- ovate, paucispiral with subcentric nucleus. Mantle edge (Fig. 11B, me) bilobed, smooth. GENERIC REVIEW OF BITTIINAE 289 FIG. 10. SEM micrographs of BiWolum variumUom Ft. Pierce, Florida (USNM 77639). A, B, D, E, two shells showing sculptural variation and shell shape; length 3.2 nnm; C, immature shell, length 2.8 mm; F, G, operculum, bar = 0.2 mm; H, sculpture of early whorls, bar = 0.3 mm; I, protoconch, bar = 88 (xm. without papillae, slightly scalloped, iridescent at edges. Palliai Cavity: Osphradiunn wide, one-third ctenidial length, weakly monopectinate, com- prising snnall, dorsally placed pectins, flanked on each side by weak ciliated strip. Ctenidium comprising long, triangular filaments with soft rods and mucus glands. Alimentary System: Radula (Fig. 11C) short. Rachidian tooth (Fig. 11D) with cutting edge of 3 small denticles on each side of central cusp. Lateral tooth (Fig. 11D) with two outer and 3-4 inner denticles. Inner marginal tooth with 3-4 inner and 2-3 outer denticles. Outer marginal tooth with 6 small inner denticles. Midesophagus with wide ciliated dorsal food groove; posterior esophagus narrow. Nervous System: Cerebral ganglia slightly larger than pedal ganglia and with short con- nective (about one-third cerebral ganglion length). Pedal ganglia nearly fused at connec- tive, each with posterior statocyst; two pairs of accessory pedal ganglia present: pair of small propodial ganglia, and larger pair of metapo- dial ganglia. Subesophageal connective be- tween subesophageal ganglion and left pleu- ral ganglion equal in length to left pleural ganglion; supraesophageal connective about equal in length to subesophageal connective. 290 HOUBRICK FIG. 11. SEM micrographs of BiWolum varium from Ft. Pierce, Florida (USNM 776639). A, B, critical point dried specimens showing external anatomical features of headfoot, bar = 0.2 mm; C, mid-section of radula, bar = 21 |i,m; D, detail of rachldian and lateral teeth, bar = 7 \?.m. amg = anterior mucus gland; eg = ciliated groove; eps = epipodial skirt; I = lip of mouth; mmg = metapodial mucus gland; op = operculum; ovp = ovipositor. Right zygoneury between subesophageal and right pleura! ganglion. Reproductive System: Ducts of testicular fol- licles joining to form spermatic duct, moving anterior as seminal vesicle, containing dimor- phic sperm. Males producing crescent- shaped spermatophore with flared bifurcate end and pointed, filamentous tip. Spermato- phores containing both eu- and parasperma- GENERIC REVIEW OF BITTIINAE 291 tozoa. Ovary cream colored, overlying brown digestive gland, extending forward to stom- ach. Palliai oviduct open, but closed in far posterior portion. Common aperture to open- ing of spermatophore bursa in lateral lamina anterior to opening of sperm pouch and open- ing of seminal receptacle located on edge of medial lamina one-third from posterior of lam- ina. Opening to spermatophore bursa not ad- jacent to opening on medial lamina, but lo- cated one-third back from anterior of lateral lamina. Spermatophore bursa comprising cil- iated and high vacuolated epithelial cells. Spawn mass composed of spirally wound thin jelly string containing many small eggs 100- 120 [i.m in diameter, hatching as veliger lar- vae, becoming planktotrophic. Bittiolum alternatum (Say, 1822) Turrltella alternats Say, 1822: 243. Pasithea nigra Totten, 1834; 369, figs. 7a, b. Bittium nigrum (Totten), Gould, 1870: 321, fig. 590. Bittium alternatum (Say), C. W. Johnson, 1915: 127. Diastoma alternata (Say), Abbott, 1974: 107, fig. 1037. Description This species is essentially the same as Bittiolum varium, described above, although the shell differs slightly in being more pupoid and less narrowly elongate. Remarks Marcus & Marcus (1963) thoroughly de- scribed the anatomy of Bittiolum varium in Brazil. My work on populations of this species from Florida basically confirms their detailed observations. In addition, the basic anatomy of the Brazilian and Florida specimens is very similar to that of Bittiolum alternatum from the American northeastern coast, suggesting that the latter is probably a sister taxon of Bittiolum varium. Bittiolum is the only genus studied in which the mantle edge is smooth, with no trace of papillae, a character noted by Marcus & Mar- cus (1963). A wavy epipodial skirt and nar- rowly elongate anterior foot are also distinc- tive external features (Fig, 2) of both examined Bittiolum species. The ovipositor (Fig. 11B, ovp) is barely visible only during the breeding season, but is basically the same as that observed in Bittium. The massive metapodial mucus gland located in the pos- terior part of the sole differs from that seen in tttibittium species, in which the slit is much longer. This gland secretes a string of mucus by which the animal can suspend itself in the algae, but the thread does not have the ten- sile strength of the mucous threads produced by members of the Litiopidae (Houbrick, 1987b). Except for major differences in exter- nal features, the radula and internal anatomy of Bittiolum varium is quite similar to that of Bittium reticulatum. The radula differs only mi- nor details (Table 2). Although Bittiolum var- ium primarily is a grazer of epiphytic microal- gae, Marcus & Marcus (1963: 79) have shown that the snail can use its anterior ctenidial filaments for particle feeding while stationary. Marcus & Marcus (1963: 88-89) found four spindle-shaped spermatophores, each 1 mm long and 0.06 mm wide, in the bursa of the lateral lamina in Bittiolum varium, and noted that the spermatophores dissolve in this bursa. The location of the spermatophore bursa in the lateral lamina is a unique feature among cerithioidean taxa, and this layout is probably the same among other members of the Bittium-group, in which the bursa in the lateral lamina has been confirmed. However, spermatophores have not been observed in this bursa in any other species. Bittiolum varium lays its eggs mostly on seagrasses. In the Indian River, Florida, I ob- served numerous irregular egg masses com- prising strands of eggs embedded in a loose jelly matrix deposited on Halodule grass blades and on ramose algae. In the spring, nearly all adults were ripe and egg laying con- tinued through the summer months tapering off in September. Bittiolum varium has been the subject of a number of ecological investigations. Virnstein & Curran (1986) measured the colonization time of this species in seagrasses in the In- dian River, Florida. Hardison & Kitting (1985) found that Bittiolum varium fed primahly on diatoms and coralline algae in seagrass meadows of the northwest Gulf of Mexico. Despite the high population densities of this snail (3,000/m^), little impact on its food could be detected. In Chesapeake Bay, Van Mont- frans et al. (1982) found that the grazing ac- tivities of Bittiolum varium, which selectively eats diatoms from blades of marine grasses. 292 HOUBRICK could have important implications for the abundance and distribution of Zostera. Bittiolum varium has a wide range in the western Atlantic, occurring from Chespa- peake Bay south to Florida and the Gulf of Mexico, throughout the Caribbean, and south to Brazil. STYLIDIUM DALL, 1907 Stylidium Dall, 1907: 178 (Type species by original designation: Bittium eschrichtii Middendort, 1849). Thiele, 1929: 211; Wenz, 1940; 757; Abbott, 1974; 106. Diagnosis Shell relatively large, dirty chalky white, smooth, weakly sculptured with four broad spiral cords defined by incised lines. Proto- conch unsculptured. Snout twice length of cephalic tentacles. Epipodial skirt poorly de- veloped, smooth along edges, but opercular lobe with small, pointed papillae. No metapo- dial mucus gland. Osphradium non-pectinate. Common aperture to sperm bursa and semi- nal receptacle in edge of anterior third of me- dial lamina of palliai oviduct. Openings to sperm bursa and seminal receptacle well- separated. Long ciliated ridge tract in lateral lamina of palliai oviduct. Development direct. Remarks This genus is represented by species living in cold-water habitats from California north to Alaska. The shell is dull and chalky under the periostracum. Shell length can be quite large (Table 3) for a member of the Bittiinae, and the large smooth protoconch, without sinusig- eral notch, is indicative of direct development. At first glance, the shell of Stylidium does not appear to fit the Bittium-group mold. How- ever, anatomical features, such as the epipo- dial skirt, large opercular lobe (Fig. 2) and pal- liai gonoduct configuration unmistakably place it Into the Bittiinae. The common aper- ture to sperm pouch and seminal receptacle is unusual in being located in the far anterior edge of the medial lamina of the palial ovi- duct, and not adjacent to the opening of the spermatophore bursa of the lateral lamina. The length of the ciliated ridge' tract of the lateral lamina is also atypical. Stylidium eschrichtii (Middendortf, 1849) (Figs. 12-14) Turriteila eschrichtii Middendort, 1849: 396- 397, pi. 11, fig. 1 (Holotype, Zoological Institute, St. Petersburg; type locality, Sitka, Alaska). Bittium (Stylidium) eschrichtii icelum Bartsch, 1907:178 (Holotype USNM 15209a; type locality, Neah Bay, Washington); 1911: 388, pi. 57, fig. 3; Ruhoff, 1973: 81. Bittium eschrichtii (Middendort). Oldroyd, 1927: 18-19, pi. 79, fig. 4. Bittium (Stylidium) eschrichtii (Middendort). Abbott, 1974: 106, fig. 1010. Description Shell (Fig. 12): Shell large, turreted, reaching 17.5 mm in length, comprising 9-11 convex whorls. Protoconch (Fig. 12G) has two smooth whorls. Early whorts (Fig. 12E-G) sculptured with three spiral bands. Adult whorls sculptured with 4 weak, widely flat- tened spiral bands separated from one an- other by deep incised spiral grooves. Penul- timate whorls with 5 wide, spiral, weak bands. Suture well defined, slightly counter-sunk into each abapical whorl. Body whorl a little less than one-third shell length, sculptured with about 8 broad spiral cords and incised lines. Shell base weakly constricted at base; ante- rior siphon broad and shallow. Aperture ovate having concave columella with weak callus; outer lip of aperture circular, crimped where spiral grooves end. Shell color chalky white- gray, covered by thin tan periostracum. Animal: Base color dirty white with trans- verse black stripes on snout, head, and epi- podium (Fig. 14A). Ciliated epithelial strip run- ning from mantle cavity floor on each side of headfoot and ending beneath peduncle of each cephalic tentacle. Ciliated gutter on right side of foot in females ending in small pink, glandular ovipositor at foot edge. Snout very long, twice length of cephalic tentacles, wide, bibbed at tip. Eyes very small. Lateral epipo- dial skirt with minute pointed papillae along edge of posterior third of foot; opercular lobe long, pointed posteriorly, darkly pigmented and with small pointed papillae along edge (Fig. 2). Anterior foot crescent-shaped with long slit along edge leading into centrally placed, ovate mucus gland deep within propo- dium. No metapodial mucus gland. Opercu- lum (Fig. 12H, I) thick, ovate, paucispiral, with eccentric nucleus. Mantle edge bilobed, with small papillae, and with slightly elongate ex- halant siphon. Mantle roof folded longitudi- nally over exhalant siphon forming dorsal, posteriorly extending ridge. GENERIC REVIEW OF BITTIINAE 293 FIG. 12. Stylidium eschrichtii \rom Carmel, California. A-D, two shells showing sculptural variation (USNM 804376), 22.4 and 20.2 mm length, respectively; E, F, SEM micrographs of immature shells showing early sculptural patterns, bar = 0.5 mm; G, SEM micrograph of protoconch and early whorls, bar = 0.3 mm; H, I, SEM micrographs of operculum, showing eccentric nucleus and attachment scar, 2.4 mm length. Palliai Cavity: Osphradiunn tan, vermiform, non-pectinate, extending length of palliai cav- ity, but slightly shorter than ctenidium. Ctenid- ium pink, comprising long, finger-like fila- ments twice length of their attached bases. Alimentary System: Radular ribbon (Fig. 13A) short. Lateral tooth (Fig. 13B) w/ith long lateral basal extension and cutting edge with 3 inner denticles, and 3-5 outer denticles; in- ner marginal tooth with 4-5 inner and 3 outer denticles. Paired salivary glands vermiform, loosely compacted, lying mostly anterior to nerve ring, but beginning behind it as thick swellings, and passing through as thin tubes. Stomach large, about one whorl in length; in- ternally with large sorling area and roundish central pad; single opening to digestive gland on right side of pad; 6-7 large transverse ribs 294 HOUBRICK FIG. 13. SEM micrographs of ra(iit\a oi Stylidium eschrichtii{USNM 804376); A, section of mid-raduiar ribbon with marginal teeth folded back, bar = 38 |j,m; B, detail of rachidian and lateral teeth, bar = 12 y.m. on left side of pad, posterior to cuticular gas- tric shield; short, wide style sac one-half stom- ach length, separate from intestinal opening. Intestine opening separated from lumen of style sac by typhlosole ridge. Nervous System (Fig. 14); Nerve ring large with thick commissure connecting cerebral ganglia. Dialyneury (Fig. 14B, d) between left palliai nerve and nerve arising from supra- esophageal ganglion. Supraesophageal con- nective (Fig. 14A, sec) twice length of right pleural ganglion. Subesophageal ganglion (Fig. 14A, sbe) closely adjacent to left pleural ganglion. Reproductive System Posterior half of palliai oviduct with thick, white, opaque albumen gland comprising flocculant transverse glan- dular ridges; mid-section of palliai oviduct with thin, weak glandular transparent walls; very thick, opaque transverse glandular ridges present in anterior third of palliai oviduct, comprising capsule gland. Sperm gutter in anterior edge of medial lamina having elon- gate common aperture to spermatophore bursa and seminal receptacle. Openings to sperm pouch and seminal receptacle within common aperture well separated. Long tube within edge of medial lamina leading to pos- teriorly placed pouch-like seminal receptacle. Large sperm pouch with internal transverse epithelial folds, occupying posterior third of medial lamina. Very long ciliated ridge tract beginning in anterior part of lateral lamina, leading into posterior spermatophore bursa. Spawn comprising thin gelatinous string wound into irregular mass. Eggs 0.2 mm in diameter. Development direct. Remarks Several subspecific taxa have been de- scribed, but it is debatable if all of these nom- inal taxa are good subspecies or merely cli- nal/ecophenotypic varieties of Stylidium eschrichtii. Abbott (1974) synonymized the subspecies icelum Bartsch with S. eschrichtii. Stylidium eschrichtii is characterized by its chalky gray, smooth shell sculptured with broad flattened spiral cords. The protoconch is large, unsculptured, and lacks a sinusigeral notch (Fig. 12G). The ovate operculum (Fig. 12H, I) with eccentric nucleus is a departure from a more circular operculum with subcen- tral nucleus, as seen in other bittiid species. Shell length seems to vary greatly among populations, but some individuals can be very large, approaching 18 mm length (Table 3). Large shell size appears to be more common in northern populations. This species lives on intertidal to subtidal rubble in cool waters of the northeastern Pa- cific. I observed a large intertidal population living among the intertices of gravel and algae GENERIC REVIEW OF BITTIINAE 295 B ses sbe 'sg sec FIG. 14. Anatomical features of Stylidium eschrich- tii. A, head and anterior foot, sfiowing pigment pat- tern; B, position of salivary glands relative to nerve ring, d = left dialaneury; leg = left cerebral gan- glion; Ipg = left pleural ganglion; Isg = left salivary gland; rcg = rigfit cerebral ganglion; rsg = right salivary gland; rpg = right pleural ganglion; sbe = subesophageal ganglion; sec = supraesophageal connective; sag = supraesophageal ganglion. at Carmel, California. According to Slrath- mann (1987), Stylidium eschriciitii has direct developnnent. Spawn is deposited on the sub- strate in gelatinous masses (presumably comprising coiled strings) containing egg cap- sules measuring 0.2 ^j^m diameter in which the embryos undergo direct development, passing through the veliger stage and hatch- ing as small snails. Z./flO?/TT/L'/W BARTSCH, 1911 Lirobittium Bartsch, 1911: 384 (Type species by original designation, Bittium catalinen- sis Bartsch, 1907). Thiele, 1929: 211; Wenz, 1940: 757; Abbott, 1974: 106; Gr?ndel, 1976: 54. Diagnosis Shell turreted, elongate, sculptured with ax- ial riblets and spiral beaded cords. Proto- conch with two spiral lirae. Varices not present on adult whorls. Operculum circular. Radular ribbon very small; radular teeth with many small denticles. Snout long; head with small cephalic tentacles and small eyes. Ovi- positor and ciliated groove on right side of foot absent. Mantle edge with long papillae. Epi- podial skirt very weakly developed. Osphra- dium vermiform, wide. Spawn comprising large egg capsules, each attached to long stalk and anchored together. Development di- rect. Remarks Bartsch (1911) divided ?/rt/um-group spe- cies from the American west coast into four genera: Bittium, Lirobittium, Semibittium, and Stylidium. His groups were defined only on superficial shell characters, such as the pres- ence or absence of varices, protoconch sculpture, and axial and spiral sculpture. Many of the species Bartsch (1911) included under his generic scheme have been ignored or referred by subsequent authors to different generic taxa. The genus Lirobittium Bartsch, from the temperate eastern Pacific, was based on mi- nor shell sculptural characters: Bartsch (1911: 384) noted that the defining characters of Lirobittium were a protoconch with two spi- ral lirae and the absence of varices from the adult whorls. These features were also men- tioned by Gr?ndel (1976: 54), who addition- ally noted that of the two primary spiral cords, the abapical one was inserted a little later. Gr?ndel (1976: 54-56) assigned Cacozeli- ana and Stylidium (with a query) as subgen- era of Lirobittium. He indicated that Cacoze- liana differed from Lirobittium by the formation of varices, and Stylidium by the suppression or complete absence of axial ribs. It has been shown herein that the Cacozeliana is sepa- rated from Lirobittium by many significant characters. The above history of Lirobittium shows that much of the confusion regarding the place- ment of the numerous California species stems from the original superficial generic de- scriptions based solely on shell morphology. It is obvious that the characters derived by these authors from minor sculptural details hardly seem to be of generic weight and have 296 HOUBRICK resulted in poorly defined, ambiguous genera with broad or discordant limits, and that have been used in varying combinations. Although shell sculpture may have some value at the specific level, it is generally not useful at the generic level, especially in cerithiids. Not a single author has included radular or opercu- lar characters and no mention is made of an- atomical features in the definition of genera. Abbott (1974: 106) considered both Bittium catalinense and B. subplanatum to be syn- onyms of Lirobittium attenuatum Bartsch, 1911, but gave no reasons for this decision. Hertz (1981: 40) showed that Lirobittium sub- planatum (cited as Bittium) was a valid spe- cies. I have examined two species of Lirobit- tium: L. catalinense.(one dried specimen) and well-preserved material of L. subplanatum. Observations on the poorly preserved, dried animal of L. catalinense are included because it is the type species of the genus, but the bulk of the descriptive anatomical characters of Li- robittium are derived from study of L. sub- planatum. The two species are anatomically very similar, have similar radulae, and are un- doubtedly congeneric. The above diagnosis and following specific descriptions represent an integrated analysis of generic characters, based on these two species. Lirobittium catalinense Bartsch, 1907 Bittium catalinensis Bartsch, 1907; 28, pi. 57, fig. 13 (Holotype: USNM 165232, type lo- cality: Santa Barbara, California [Pleis- tocene]); Abbott, 1974: 106, fig. 1013. Bittium (Lirobittium) catalinense Bartsch, 1911:402-403, pi. 51, fig. 1. Remarks The type species of this genus is a Pleis- tocene fossil, but Bartsch (1911) described many subspecies, some of which are Recent. Bittium cataliense is now regarded as a syn- onym of "Bittium"attenuatum Carpenter, 1864 (Abbott, 1974: 106). Examination of a reconstituted, dried spec- imen of the type species of Lirobittium, Bittium catalinense (= Bittium attenuatum), showed that the animal is basically the same as Liro- bittium subplanatum. It is relatively unpig- mented, has a large, broad snout, bilobed at the anterior end and short cephalic tentacles, about half the snout length. The mantle edge has many long papillae along its dorsal and lateral sides, while the mantle edge forming the inhalant siphon has large paddle-shaped papillae. The buccal mass is small, and the radula minute, about one-thirteenth the shell length. The rachidian tooth has a triangular basal plate with a long glabrella and is as wide as tall; there is a deep concave inden- tation and a cutting edge with a long pointed central cusp flanked on each side by 4-5 small denticles. The lateral teeth are deeply concave on the top, have a wide basal plate with a large central buttress, and have numer- ous small denticles. The marginal teeth are slender, and serrated along their tips with many small pointed denticles (Fig. 15). Lirobittium subplanatum (Bartsch, 1911) (Figs. 15-17) Bittium (Semibittium) subplanatum Bartsch, 1911: 395-396, pi. 57, fig. 5 (Holotype, USNM 160076; type locality, Catalina Id., California); Oldroyd, 1927: 23: Ruhoff, 1973: 130. Bittium subplanatum Bartsch. Dali, 1921:146; Hertz, 1981:40, figs. 23-27. Bittium subplanatum Bartsch. Oldroyd, 1927: 23. Bittium (Lirobittium) subplanatum (Batsch). Abbott, 1974: 106. Description Shell (Fig. 15): Shell elongate, turreted, com- prising 8-9 moderately inflated whorls. Pro- toconch (Fig. 15) about 1.5 whorls, well rounded, smooth. Early whorls sculptured with two major spiral lirae, soon crossing over axial riblets (Fig. 15). Adult whorls sculptured with three major spiral cords crossed over by numerous thin axial ribs (24-26), forming cancellate appearance; small beads occur- ring at crossover points. Body whort (Fig. 15) sculptured with four major spiral cords and numerous axial ribs; moderately constricted at base. Shell base with about 7 spiral cords. Aperture ovate with oblique columella and curved, thin outer lip. Anterior canal moder- ately developed; anal canal weak. Shell color white, covered with brown periostracum. Animal (Fig. 16A, B): Animal pure white with pink buccal mass showing through snout. Head large with very large, wide, extensible snout, dorso-ventrally flattened, bilobed at tip; cephalic tentacles small, a little less than one- third snout length, each with small black eye adjacent to opaque white spot at tentacular peduncular base. Snout ringed with many GENERIC REVIEW OF BITTIINAE 297 FIG. 15. SEM micrographs of shells of Lirobittium subplanatum from Palos Verdes, California (USNM 881021). A, bar = 1.8 mm; B, detail of protoconch and early teleoconch sculpture, bar = 0.6 mm; C, bar = 1.8 mm. deep, transverse epithelial folds (Fig. 16B). Foot with very weak epipodial skirt and with- out papillae or distinctive operculiferous lobe. No ciliated groove on right side of foot; no ovipositor. Anterior of sole crescent shaped with deep transverse slit marking entrance to anterior mucus gland. No metapodial mucus gland. Mantle edge bilobed, fringed with many papillae emerging from ventral side of mantle edge. Palliai Cavity: Osphradium brown, vermi- form, without pectins, wide, about one-third the ctenidial width, nearly equaling ctenidial length. Ctenidium extending length of palliai cavity. Hypobranchial gland thick, comprising transversely ridged glandular tissue. Alimentary System: Mouth at tip of snout, de- fined by pair of fleshy pads. Buccal mass (Fig. 16B, bm) pink, small, about one-third snout length. Radular ribbon (Fig. 17) small, about one-ninth shell length. Rachidian tooth (Fig 17C) with large glabrella, long serrated cen- tral cusp and 6 small denticles on each side. Lateral tooth (Fig. 17 B,C) with broad basal plate; cutting edge has large denticle with 6 inner denticles and 15-17 outer denticles. Marginal teeth (Fig. 17D) long, curving; inner marginal tooth with 15-19 inner denticles, large central cusp and 5-6 outer denticles; outer marginal tooth same, but lacking outer denticles. Stomach with central pad, gastric shield, short style sac and crystalline style; one opening to digestive gland. Nervous System: Cerebral ganglia joined by short connective. Pleural ganglia close to ce- rebral ganglia; left pleural ganglion connected to subesophageal by very short connective. Supraesophageal connective about two- thirds length of right pleural ganglion. Reproductive System (Fig. 16A); Testis white, producing dimorphic sperm; ovary cream-yellow containing large ova, 0.5 mm in diameter. Glandular portion of female palliai oviduct comprising many transverse folds, posterior opaque white portion comprising al- bumen gland (Fig. 16A, ag), and anterior, transparent greyish-white portion comprising capsule gland (Fig. 16A, eg). Anterior two- thirds of edge of medial lamina with large sperm gutter (Fig. 16A, sg) leading into deep slit containing two openings: anterior opening (Fig. 16A, osp) into large sperm bursa and posterior opening (Fig. 16A, osr) into small tubular sac-like seminal receptacle (Fig. 16A, sr). Lateral lamina less glandular than medial lamina and with short ciliated ridge tract (Fig. 16A, crt) leading into opening of spermato- phore bursa (Fig. 16A, osb), adjacent to openings on medial lamina. Spermatophore bursa (Fig. 16A, sb) small, elongate, sac-like. Discussion Bartsch (1911) assigned this species to the subgenus Semiblttium, and his assignment was followed by Dall (1921), Oldroyd (1927), and Hertz (1981). Semiblttium is shown herein to comprise a group of Eocene fossils probably related to the extant Australian mo- notypic genus Cacozellana, which differs con- siderably in anatomy from the California spe- cies. Abbott (1974) transferred this species, which he considered a synonym of BIttlum at- tenuatum Carpenter, 1864, to Lirobittium, but gave no reasons for doing so. The shell is of moderate size (Table 3) and has a large protoconch sculptured with two spiral lirae and lacking a sinusigeral notch. Although the shell of Lirobittium subplanatum does not resemble that of Stylidlum es- chrlchtil, the anatomical features of the two species are quite similar. As far as can be seen in preserved material, Lirobittium sub- planatum appears to have a very weak epi- podial skirt, but closer examination of living animals may show that this character is com- 298 HOUBRICK FIG. 16. Lirobittium subplanatum. A, palliai oviduct, spread open to reveal details; B, head, showing broad snout, short cephalic tentacles and small buccal mass; C, dorsal view of attached spawn mass, showing individual capsules with enclosed embryos and attachment strands, ag = albumen gland; ant = anterior of palliai oviduct; bm = buccal mass; eg = capsule gland; cod = coelomic oviduct; crt = ciliated ridge tract; osp = opening to sperm pouch; osb = opening to spermatophore bursa; ovg = oviductal groove; sb = spermatophore bursa; sg = sperm groove; sp = sperm pouch; sr = seminal receptacle. pletely absent. The operculum also differs in being more typically rounded than that of Sty- lidium. The radula of Lirobittium subplanatum (Fig. 16) is very similar to that of Lirobittium atten- uatum, but differs in havjng many more den- ticles on the teeth. The exact dentition for- mula is given in Table 2. There has apparently been some difficulty in identifying this species, as it has been con- sidered synonymous with a number of other sympatric species, but Hertz (1981) has shown that it is a distinct, valid species. As mentioned above, the radula is distinct. Lirobittium subplanatum lives offshore on sandy-rubble bottoms. The shell is frequently severly eroded and abraided. Spawn morphology of Lirobittium is unique among Bittiinae (Fig. 17C) and is deposited on pieces of rubble or empty shells. It com- prises clusters of large egg capsules, each about 0.5 mm in diameter and containing one embryo. Each egg capsule is connected by a strand to a central attachment point so that the spawn mass looks like a group of small balloons with their strings attached together. Embryos revolve slowly with their capsules, where they pass through the veliger stage. GENERIC REVIEW OF BITTIINAE 299 FIG. 17. SEM micrographs of radula of LirobiWum subplanatum (USNM 881021). A, radular ribbon with marginal teeth spread open, bar = 35 |j.m; B, half row showing rachidian and lateral teeth, bar = 19 [?.m; C, detail of dentition of rachidian and lateral teeth, bar = 10 |xm; D, detail of dentition of marginal teeth, bar = 12 (im. finally hatching out as small snails. Develop- ment is direct (pers. obs.). CACOZEUANA STRAND, 1928 ? Semibittium Cossmann, 1896: 29 (Type species by original designation: Cerith- ium cancellatum Lamarck, 1804; not Semibittium Bronn, 1831 ; nor Lea, 1842; nor Tuomey, 1848; nor J. de C. Sowerby, in Dixon, 1850). Thiele, 1929: 211; Wenz, 1940: 756; Gr?ndel, 1976: 56-57. Cacozelia Iredale, 1924: 246 (Type species by monotype: Cerittiium lacertinum Gould, 1861); not Cacozelia Grots, 1878 [Lepidoptera]. Thiele, 1929: 211 ; Murray, 1969: 111. 300 HOUBRICK Cacozeliana Strand, 1928: 66 (new name for Cacozelia Iredale, 1924). Wenz, 1940: 756, Lirobittium {Cacozeliana) Strand. Gr?ndel, 1976: 54-55. Diagnosis Shell large, elongate with many weakly in- flated whorls, sculptured with four beaded spiral cords per whorl and having overall pus- tuloso appearance. Protoconch unsculptured except for microscopic subsutural pustules, but large sinusigeral notch present (Fig. 18F). Operculum circular-ovate, paucispiral with subcentric nucleus and fringed edges. Epipo- dial skirt with smooth edges. Snout short, nar- row. Opercular lobe lanceolate and with lon- gitudinal median groove. Large ovipositor gland on right side of foot. Osphradium bipec- tinate. Salivary glands anterior to nerve ring. Rachidian tooth without glabrella. Openings to sperm bursa and seminal receptacle well separated. Seminal receptacle comprising several grape-like lobes. Remarks The genus Cacozelia was proposed by Ire- dale for Cerithium lacertinum Gould, a sub- jective synonym of Cerithium granarium Kiener. The living Australian species is thought to be congeneric with the Paris Basin Eocene species Cerithium cancellatum La- marck, which is the type species of Semibit- tlum Cossmann; however, as Cacozelia is a junior homonym, the name Cacozeliana was subsequently proposed by Strand (1928) as a replacement. The allocation of Cacozeliana as a subgenus of Liocerithium by Gr?ndel (1976) was made on the observation that In Cacozeliana, the fourth primary spiral cord is initially weaker than the three formed earlier, whereas in Liocerithium all four are equally strong. Gr?ndel (1976) also pointed out that varices are present in the subgenus, whereas they are absent in Lirobittium. These minor sculptural differences hardly seem appropri- ate as generic-level characters; furthermore, radular and anatomical characters of Cacoz- eliana show that it is far-removed from Liro- bittium. The type species of Semiblttlum, which is placed into synonymy with Cacozeliana with a query, is an Eocene fossil from the Paris Ba- sin, Cerithium cancellatum Lamarck. This fos- sil species is conchologically very close to Cerithium granarium Kiener, the living type species of Cacozeliana from southern Austra- lia redescribed herein; however, because the anatomy of the fossil is unknown, it is impos- sible to declare with confidence that the two species are congeneric. Gr?ndel (1976: 56) considered the Eocene genus Semiblttlum to be separate from Cacozeliana. He noted that the shell of Semiblttlum species has a slight varix on the lip of the protoconch followed by an almost simultaneous insertion of the three primary spiral cords. The name Cerithium cancellatum Lamarck is preoccupied, and needs a replacement name. Moreover, the name Semiblttlum cannot be used because it is thrice preoccupied. The possibility that Ca- cozeliana granarla is a living survivor of the Eocene genus Semiblttlum represented by Cerithium cancellatum should be considered, because several other Tethyan Eocene cer- ithioidean genera survive among the living Australian molluscan fauna; e.g., Diastoma Deshayes, 1850; Gourmya Fischer, 1884; Campanile Fischer, 1884; and Plesiotrochus Fischer, 1878 (Houbrick, 1981b, 1981c, 1981d, 1990b, respectively). It is also notable that Cacozeliana falls out at the base of the cladogram (Fig. 1) as the closest taxon to the outgroup. Moreover, Cacozeliana is sepa- rated from all other Bittium-group genera by five non-homoplastic synapomorphies (Fig. 1), further demonstrating its distinctiveness. Gr?nders (1976: 56-57) separation of Semi- bittium from Cacozeliana was based on the order of the insertion of spiral lirae on the early whorls, but this character has not been shown to be of generic weight, and therefore is not seriously considered herein. If Cacoze- liana is truly congeneric with Semiblttlum, the genus would date from the Eocene, when the latter was common in the Paris Basin fauna (Cossmann, 1906:138). Cacozeliana is today monotypic and confined to the temperate wa- ters of southern Australia. The type species, Cacozeliana granar?a (Kiener), undoubtedly has the largest shell of any representative of the subfamily Bittiinae and differs from other species of the group in several ways: 1. The short narrow snout (Fig. 20A) is dis- tinctive, as is the fringed operculum (Fig. 1BG). 2. The rachidian tooth of Cacozeliana gra- narla is unique, differing from other Bittiinae members in lacking a glabrella on the basal plate. Additionally, the rachidian tooth lacks concave sides and a strong pair of basal but- tresses (Fig. 19B). Moreover, the lateral basal GENERIC REVIEW OF BITTIINAE 301 extensions of the basal plate are nearly ab- sent. 3. The palliai oviduct of Cacozeliana grana- rla (Fig. 20C), while having a typical layout, is unique among known palliai oviducts in the S/??/um-group in having the seminal recepta- cle divided into several grape-like lobes (Fig. 20C, sr) and in having a highly developed, swollen anterior capsule gland (Fig. 20C, eg). As pointed out earlier, a grape-like seminal receptacle also occurs in some species of Cerithium Brugui?re, 1789, Rhinoclavis Swainson, 1840, and in Dialak. Adams, 1861 (Houbrick, 1971, 1978, 1992, pers. obser.; Ponder, 1991), although this structure in Diala is not proven to be a seminal receptacle. This kind of seminal receptacle does not necessar- ily indicate relatedness among these groups: the bulging, grape-like morphology may be due to the swollen state of the filled seminal receptacle and may represent sexual "ripe- ness" rather than a distinct morphological character state of the seminal receptacle. Cacozeliana granar?a (Kiener, 1842) (Figs. 18-20) Cerithium granarium Kiener, 1842: 72-73, pi. 19, fig. 3 (Holotype MNHNP; type local- ity, "les c?tes de Timor," in error, here corrected and restricted to Albany, West- ern Australia); G. B. Sowerby, 1855: 879, pi. 184, figs. 225-227; 1865: pi. 19, fig. 135; Kobelt, 1898: 249, pi. 23, fig. 9. Ceritliium lacertinum Gould, 1861: 368 (Ho- lotype USNM 16571; type locality Syd- ney Harbor, New South Wales, Austra- lia); 1862: 141; G. B. Sowerby, 1866: pi. 18, fig. 128; Tryon, 1884: 155, pi. 30, fig. 100; R. Johnson, 1964: 96, pi. 11, fig. 4. Bittium granarium (Kiener). Tryon, 1887: 155, pi. 30, fig. 98; Wells, 1984: 30-31. Synonymic Remarks Kiener's (1842) name, granarium, predates Gould's (1861) lacertinum. Examination of the holotypes of both taxa leaves no doubt that the two are conspecific. Description Stielt (Fig. 18): Shell large, elongate, tur- reted, reaching 24 mm in length comprising 12-13 nearly flat-sided whorls sculptured with four beaded spiral cords. Protoconch (Fig. 18F) comprising two smooth whorls with weak, microscopic subsutural pustules, no spiral lirae, and with deep sinusigeral notch. Early whorls (Fig. 18H) sculptured with 3 spi- nosely beaded spiral cords alined to form about 12-13 axial riblets. Adult whorls slightly beveled abapically, defining weak suture. Body whorl one-third shell length, having 6 spiral beaded cords and weakly constricted base. Aperture ovate, small, about one-fifth shell length. Columella concave with weak columellar callus and smooth, rounded outer lip. Anterior canal short, narrow, well defined. Shell color white to tan, blotched with pink to reddish brown and having brown spiral bands with white flecks (Fig. 180, D). Beads some- times white (Fig. 18A B). Periostracum light tan, thin. Animal (Fig. 20): Head, snout and epipodium pigmented tan with chocolate blotches, tiny white spots, and irridescent green. Oephalic tentacles darkly pigmented, having many black spots, slender, elongate, aboui twice snout length. Snout narrow, short (Fig. 20A, sn) with flared bilobed tip. Mantle edge fringed with very small papillae each bearing white spot. Pair of ciliated strips emerging from mantle floor and running to base of cephalic tentacles on each side of headfoot. Deep ciliated groove running down right side of foot to edge, ending in small flap in males. Ciliated groove in females having thick glan- dular strips on each side of groove, compris- ing ovipositor. Epipodial skirt poorly devel- oped, smooth along edge, forming short lanceolate opercular lobe with dorsal longitu- dinal furrow and without papillae along edge. Orescent-shaped propodial slit at edge of an- terior foot leading into deep oval anterior mu- cus gland (Fig. 20A, amg). Longitudinal fold in middle of sole, but no metapodial mucus gland present. Operculum (Fig. 18G) circular- ovate, paucispiral, with subcentral nucleus. Opercular spiral fringed with thin lamella (Fig. 18G). Paillai cavity: Osphradium bipectinate, with weak pectins. Osphradium equaling ctenidial length. Ctenidium comprising light tan elon- gate, triangular filaments. Hypobranchial gland thick, comprising irregular transverse glandular folds, secreting large amounts of mucus. Alimentary system (Fig. 19B): Buccal mass large, filling snout cavity, having small jaws and short radula (Fig. 19A). Rachidian tooth (Fig. 19B) with rectangular basal plate lacking 302 HOUBRICK FIG. 18. Cacozeliana granar?a ^rom King George Sound, Western Australia (USNM 858551). A-D, two shells showing variation in color pattern and sculpture, length 22.4 mm and 20.2 mm, respectively; E, SEM micrograph of immature shell, bar = 0.6 mm; F, SEM micrograph of protoconch, bar = 16 (xm; G, SEM micrograph of operculum, bar = 0.8 mm; H, SEM micrograph showing early sculpture, bar = 0.8 mm. strong basal lateral buttresses, with straight base and equal in length to top of tooth; cut- ting edge w/ith small central cusp flanked by two denticles on each side. Lateral tooth (Fig. 19B) with one inner denticle and 3-4 outer denticles. Inner marginal tooth with 5-6 inner denticles and 3-4 outer denticles. Outer mar- ginal tooth (Fig. 19A) with 4 inner denticles. Salivary glands (Fig. 208, Isg, rsg) paired, vermiform, coiled, lying anterior to nerve ring. Midesophagus expanded laterally having many transverse internal epithelial folds com- prising esophageal gland. Stomach with one digestive gland opening to left of large central pad dividing left sorting area from right gastric shield complex. Style sac separated from in- testinal opening by large typlosole fold. Nervous System (Fig. 20, B): Cerebral gan- glia joined by short connective, one-third the ganglion length. Subesophageal ganglion very close to left pleural ganglion. GENERIC REVIEW OF BITTIINAE 303 FIG. 19. Radula of Cacozeliana granar?a from King George Sound, Western Australia (USNM 858551). A, mid-section of radula, bar = 60 ^.m; B, details of racfiidian and lateral teeth, bar = 15 ^.m. 1mm osp rpg 0.25mm FIG. 20. Anatomical features of Cacozeliana granar?a. A, head and foot anterior, showing narrow snout; B, position of salivary glands anterior to nerve ring; C, paillai oviduct, spread open to reveal interior details, a = anterior end of palliai oviduct; ag = albumen gland; eg = capsule gland; cod = coelomic oviduct; ctr = ciliated ridge tract; Isg = left salivary gland; osb = opening to spermatophore bursa; osp = opening to sperm pouch; osr = opening to seminal receptacle; rpg = right pleural ganglion; rsg = right salivary gland; sb = spermatophore bursa; sg = sperm groove; sp = sperm pouch; sr = seminal receptacle. Reproductive System: Male palliai gonoduct thick, glandular, having wide transverse folds forming spermatophore organ in posterior half; anterior half of male palliai gonoduct less glandular, white but not opaque. Female pal- liai oviduct (Fig. 20C) having seminal recep- 304 HOUBRICK tacle comprising several grape-like lobes in medial lamina (Fig. 20C, sr). Openings to the sperm pouch (Fig. 20C, osp) and seminal re- ceptacle (Fig. 20C, osr) separated by long cil- iated groove. Ciliated ridge tract (Fig. 20C, ctr) beginning behind anterior capsule gland (Fig. 20C, eg) comprising many swollen trans- verse elements. Opening to spermatophore bursa (Fig. 200, osb) in lateral lamina adja- cent to opening of sperm pouch in medial lamina. Spawn mass comprising a jelly string containing many encapsulated eggs, 0.1-0.13 mm diameter, wound into flattened coil about 20 mm wide. Eggs opaque, white, each within hyaline capsule. Development in- direct with free swimming veliger stage. Discussion Although the shell of Cacozeliana granar?a (Fig. 18) looks very much like those of some Centhium species, the weak epipodial skirt, palliai oviduct, and other anatomical features are very typical of members of the Bittiinae. The protoconch, as indicated by Gr?ndel (1976), differs from those of most other gen- era in being nearly smooth, and in lacking any spiral threads (Fig. 18F; Table 3), but it does have a deep sinusigeral notch, indicative of planktotrophy. Stylidium species also have a smooth protoconch. The operculum of Caco- zeliana is unusual in having a thin lamellar- like fringe along its spiral (Fig. 186). The shell of this species is undoubtedly the largest of any member of the S;Y//t/m-group (Table 3), but the aperture is very small in relation to the shell length. There is much color variation within populations. The early life history of this species has been described by Murray (1969), who illus- trated the spawn (1969; pi. 17). The spawn comprises a coiled gelatinous thread contain- ing encapsulated eggs that hatch as plank- totrophic veligers. Murray (1969) stated that 8-9 days after deposition, veliger-stage em- bryos hatched out and were maintained in sea water containers for up to 10 weeks. Cacozeliana granar?a is found in the shal- low subtidal, temperate waters of southern Australia where it is common among Posi- donia, Zostera, and other sea grasses. It also occurs on moderately exposed and sheltered shores, on sandy-muddy bottoms, under stones, and on rocky areas. I observed large populations of this species living on algal mats and on Posidonia grass blades in King George Sound, Western Australia, and in FIG. 21. SEM micrographs of shell of Argyropeza divina Melvill & Standen, from Refugio Id., Tanon Str., Philippines (USNM 302513); A, B, apertura! and dorsal views of adult shell, 6.3 mm length; C, protoconch showing sculpture and sinusigeral notch, bar = 1 mm. similar habitats in Sydney Harbor and Botany Bay, New South Wales. ARGYROPEZA MELVILL & STANDEN, 1901 Argyropeza Melvill & Standen, 1901:371-372 (Type species by original designation, Ar- gyropeza divina Melvill & Standen, 1901 ). Thiele, 1929: 212; Wenz, 1940: 757; Gr?ndel, 1976: 44; Houbrick, 1980a: 2. Diagnosis Shell small, turreted, thin and vitreous, sculptured with axial and spiral elements, va- rices, and with many small nodules. Proto- conch comprising three and a half whorls with deep sinusigeral notch; sculptured with two GENERIC REVIEW OF BITTIINAE 305 FIG. 22. SEM micrographs of radula of Argyropeza divina (USNM 302513), A, radular ribbon with marginal teeth spread open, bar = 100 |xm; B, half row, bar = 50 \?.m. spiral cords and many minute subsutural folds. Aperture ovate with well-developed, short anterior canal. Operculum corneous, subcircular, paucispiral, with subcentral nu- cleus. Snout broad with large cephalic tenta- cles and large eyes. Foot with anterior mucus gland. Mantle edge papillate. Palliai gono- ducts open. Radula taenioglossate; rachidian tooth wider than tall; lateral tooth with trans- verse ridge on basal plate; marginal teeth slender, scythe-shaped. Remarks An alpha-level review of Argyropeza has been published by Houbrick (1980a), which should be consulted for details about taxon- omy, morphology and geographic distribution. The genus comprises five described species and several undescribed ones (pers. obser.). Members of this genus live on fine-grained substrates of deep water shelves and slopes, and not much is known about their biology. All examined species have small shells and pro- toconchs sculptured with two spiral lirae, sub- sutural pleats, and a deep sinusigeral notch (Fig. 21C; Table 3) indicative of a plank- totrophic larval stage. The anatomy of Argy- ropeza species is virtually unknown except for superficial observations made from reconsti- tuted, dried specimens. The shell and radula of the type species, Argyropeza divina Melvill & Standen, 1901, are shown in Figures 21 and 22. I do not agree with Powell's (1979) suggestion that Tasmalira Dell, 1956, may be closely related to Argyropeza, because the shell morphology does not appear to fit the limits of the genus. Argyropeza is tentatively assigned to the Bittiinae until more complete anatomical information is available. VARICOPEZA GR?NDEL, 1976 Varicopeza Gr?ndel, 1976: 46 (Type species by tautonomy, Varicopeza varicopeza Gr?ndel, 1976). Houbrick, 1980b: 525; 1987: 85. Diagnosis Shell small, slender, turreted, vitreous, hav- ing impressed suture, and sculptured with strong spiral cords, weaker axial elements, and many nodules. Protoconch having three and one-half smooth whorls, with weak, me- dian spiral cord, minute subsutural pustules, and sinusigeral notch. Aperture ovate with short, well-developed anal and anterior ca- nals. Operculum corneous, ovate, paucispi- ral, with subcentral nucleus. Radula taenio- 306 HOUBRICK FIG. 23. SEM micrographs of shell of Varicopeza pauxilla (A. Adams, 1854) from Nagubat Id., E. Min- danao, Philippines (USNM 276898). A, B, apertural and side views of adult shell, 8.1 mm length; C, protoconch, bar = 100 J?-H?I. glossale with hourglass-shaped rachidian tooth; lateral tooth with transverse ridge on basal plate; marginal teeth elongate, slender with denticulate sickle-shaped tips. Animal with large headfoot, elongate, wide snout, long cephalic tentacles and very large eyes. Deep ciliated groove on right side of foot. Mantle edge having short, thick papillae. Remarks The two known species of Varicopeza have been thoroughly described by Houbrick (1980b, 1987a). These publications should be consulted for specific information about tax- onomy and a detailed description of the type species. The shell is of moderate length (Ta- ble 3) and has a protoconch sculptured with one spiral lira and a shallow sinusigeral notch (Fig. 23C). Although the shell and radula (Fig. 24) are well described, only a few external anatomical features are known. Varicopeza species occur at moderate subtidal depths on fine-grained substrates in the tropical Atlantic and Pacific. The shell sculpture of Varicopeza (Fig. 23A, B) is similar to that of Argyropeza species, differing chiefly in protoconch mor- phology. The aperture (Fig. 23A, B) is distinc- tive in having a large, flaring anal sinus. The radula (Fig. 24) has more denticles on the marginal teeth than in Argyropeza (Table 2). Grijndel (1976) suggested that Varicopeza was closely related to the extinct Jurassic ge- nus Cryptaulax and considered it to be a Re- cent representative of the of the extinct family Procerithiidae Cossmann, 1905. The shell and radula of Varicopeza pauxilla (A. Adams, 1854) is shown in Figures 23 and 24. This genus is tentatively assigned to the Bittium- group until more complete anatomical infor- mation is available. ZEBITTIUM FmiAV, 1927 Zebittium Finlay, 1927; 381 (Type species by original designation, Cerithium exilis Hut- ton, 1873); Wenz, 1940; 756; fig. 2191; Powell, 1979: 132, fig. 32:1. Diagnosis Shell very small, turreted, sculptured with beaded spiral cords, and weak axial riblets, having impressed suture. Aperture ovate with weak notch-like anterior canal. Protoconch two and a half whorls, bluntly rounded, un- sculptured. Remarks This genus was proposed without any de- fining characters, and was apparently intro- duced only to accomodate the New Zealand species, Bittium exile Hutton and Bittium vit- reum Suter. The shell of Zebittium exile (Hut- ton, 1873) is shown in Figure 25. Zebittium was assigned as a subgenus of Bittium by Wenz (1940), who noted that the genus oc- cured from the Miocene to the Recent of New Zealand. The shell of the type species closely resembles those of Bittium and Bittiolum spe- cies and does not appear to have any distin- guishing features of generic significance. The unsculptured protoconch (Fig. 25D) appears to indicate lecithotrophic development. No preserved material of this species was avail- GENERIC REVIEW OF BITTIINAE 307 FIG. 24. SEM micrographs of radula of Varicopeza pauxilla. A, section of ribbon with some marginal teeth spread open, bar = 50 i^m; B, detail of rachidian and lateral teeth, bar = 25 |j,m. able for study; therefore, the genus ZebiWum is included in this review only tentatively. CASSIELLA GOFAS, 1976 Cassiella Gofas, 1987: 109 (Type species by original designation, Cassiella abylensis Gofas, 1987). Diagnosis Shell small, slender, turrited, sculptured with spiral cords, without varices and with im- pressed suture. Aperture ovate, without ante- rior canal and simple outer lip. Operculum corneous, ovate, paucispiral, with subcentral nucleus. Animal with bilobed snout and two elongate cephalic tentacles. Foot short and broad without ovipositor or ciliated groove on right side, and with large opercular lobe. Rad- ula taenioglossate; rachidian tooth with squarish basal plate, moderately concave on each side with small median glabrella, and having cutting edge with large central cusp flanked by 3 smaller denticles on each side. Lateral tooth with large triangular cusp with one small inner denticle and 7-8 outer denti- cles. Marginal teeth elongate, spatulate with curved tips; inner marginal teeth denticulate on both sides; outer marginal teeth lacking outer denticles. Remarks This monotypic genus was recently pro- posed and described by Gofas (1987), and his publication should be consulted for de- scriptive details of the genus and figures of the type species. Cassiella abylensis does not fit easily into the S/ff/um-group, although there are some resemblances. The shell of Cassiella abylensis (Fig. 26) varies highly in color pattern and in spiral sculpture (Gofas, 1987: 111). The shell morphology is unlike those of other members of the S/YI/um-group. No vestige of an anterior canal is present, and the shell morphology strongly resembles those of some rissoids. The absence of an anterior canal is also a feature of Cerithidium Monerosato, a taxon I have excluded from Bittiinae. The external anatomy of Cassiella abylen- sis was depicted by Gofas (1987: figs. 10, 14, 15). The animal does not have epipodial ten- tacles, although there is an inconspicuous groove around the foot, just above the edge of the sole, which may be homologous with the epipodial skirt found in members of Bittiinae. The opercular lobes are said to be "massive" (Gofas, 1987: 111 ), but they are not depicted or labeled in the figures of the external anat- omy. The headfoot, operculum, and radula are not unlike those observed in other species 308 HOUBRICK FIG. 25. SEM micrographs of shell of Zebittium ex- ile (Hutton, 1873) from Long Bay, Auckland, New Zealand (USNM 681043); A, apertural view of adult shell, 4.7 mm length; B, dorsal view, 4.6 mm length; C, immature shell, 4.4 mm length; D, protoconch, bar = 0.25 mm. of Bittiinae. There is no metapodial mucus gland, no ovipositor is indicated, and males are aphallate (Gofas, 1987: 111). Pending further anatomical studies, the eastern Atlantic taxon Cassiella is tentatively assigned to Bittiinae with doubt. ACKNOWLEDGEMENTS This study was accomplished In many di- verse places and with the help of many col- leagues and friends. I wish to thank Dr. Anto- nio Prias Martins, of the University of the /Azores, for sponsoring me at the First Inter- national Workshop of Malacology, held at Sao Miguel, Azores. This part of my study was supported by a grant of the Portuguese Uni- \'ersity of the Azores and the Sociedade de FIG. 26. SEM micrographs of shell of Cassiella abylensis Gofas, 1976, from Ceuta, Spain (USNM 869532); A, apertural view of shell, 2.3 mm length; B, dorsal view of shell, 2.5 mm length. Estudos A?orianos "Alfonso Chaves." Work on the Western Atlantic species was done at the Smithsonian Marine Station, Link Port, Florida. I am grateful to Dr. Mary Rice and the staff of the marine station for their assistance throughout this project. This paper is Smith- sonian Marine Station contribution No. 272. Work in Hawaii and Guam was supported by two grants from the Smithsonian Secretary's Research Opportunity Fund. I am grateful to the University of Guam for laboratory space, equipment and logistic support. I thank Dr. Michael Hadfield, of the University of Hawaii, for providing laboratory space at the Pacific Biom?dical Research Laboratory, and tor his assistance with field work. A grant from the Smithsonian Secretary's Research Opportu- nity Fund supported field and laboratory stud- ies and attendance at the Workshop on Ma- rine Biology at Albany, Western Australia. I am Indebted to Dr. Fred Wells, Western Aus- tralian Museum, Perth, for his assistance in the field. Dr. Henry Chaney, Mrs. Barbara Chaney, and Mr. Paul Scott of the Santa Bar- bara Museum of Natural History, provided lo- gistic and field assistance In an heroic, alas unsuccessful, attempt to find living Lirobittium specimens. I thank Don Cadlen for sending me live specimens of "Semibittium" sub- planatum Bartsch from off Palos Verdes, Cal- ifornia, and am grateful to Serge Gofas, Nat- ural History Museum, Paris, for sending shells GENERIC REVIEW OF BITTIINAE 309 of Cassiella abylensls. For technical assis- tance (proofreading and SEM, and computer macro design) I thank Shelley Greenhouse, National Museum of Natural History, Smith- sonian Institution. Susanne Braden, National Museum of Natural History, Smithsonian In- stitution, provided technical assistance with SEM operation. John Wise provided valuable assistance in learning various aspects of the Hennig86 and GLADOS programs. Finally I am grateful to Dr. Winston F. Ponder for crit- ically reading a draft of this paper and for stimulating discussions and exchanges of data about anatomy and evolution of small- sized cerithioidean taxa. LITERATURE CITED ABBOTT, R. T., 1974, American seashells, 2ncl ed.: 663 pp., illus. New York, Van Nostrand. ADAMS, A., 1860. Mollusca Jap?nica: new species of Aclis, Ebala, Dunl4 history of British Mollusca and their shells, vol. 3. Van Voorst, London. 616 pp. FRETTER, V., 1948, The structure and life history of some minute prosobranchs of rock pools: Ske- neopsis planorbis (Fabricius), Omalogyra ato- mus (Philippi), Rissoella diaphana (Alder) and Rissoella opalina (Jeffreys). 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