Page:American Seashells (1954).djvu/377

8 mm. in length, conical, slightly compressed dorso-ventrally (oval in cross-section); apex slightly recurved dorsally; surface with transverse grooves; embryonic shell small, smooth, bulbous and separated from the main shell by a constriction. This is the only species in the genus. Genus Clio Linne 1767 Shell of a somewhat angular form, colorless, compressed dorso-ventrally, and with lateral keels. A cross-section of the anterior or open portion is thus always angular at the sides. There is generally a crest or ridge extending longitudinally along the back. Embryonic shell varies in form, but is always definitely separated from the rest of the shell. Cleodora Peron and Lesueur 1 8 1 o is the same genus. Clio pyramidata Linne Pyramid Clio Figure 64k Worldwide, pelagic. 16 to 21 mm. in length. No lateral keels on the posterior portion; with- out lateral spines. Lateral margins very divergent. No posterior transverse grooves. Dorsal ribs undivided. Common. C. Imiceolata Lesueur and Cleo- dora exacuta Gould are this species. The shell exhibits considerable variation in form. Clio cuspidata Bosc Cuspidate Clio Figure 641 Atlantic and Indo-Pacific, pelagic. Without lateral keels on the posterior portion. Lateral spines very long. Common. Clio recurva Children Wavy Clio Figure 64J Atlantic and Indian Ocean. Warm water, pelagic. I inch in length, with lateral keels over its entire length. 3 dorsal ribs markedly projecting. A large, fragile, transparent and very exquisite species. This is C. balantiiim Rang. Clio polita Pelseneer Two-keeled Clio Figure 64I Atlantic, pelagic. With lateral keels over its entire length. Dorsal ribs very slightly pro- jecting. The posterior portion of the shell is narrow. C. j ale at a Pfeffer is the same species.