CAVOLINIDAE 295 



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. 



