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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
Worldwide, pelagic.
Figure 64k
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
Atlantic and Indo-Pacific, pelagic.
Figure 641
Without lateral keels on the posterior portion. Lateral spines very long.
Common.
Clio recurva Children Wavy Clio
Atlantic and Indian Ocean. Warm water, pelagic.
Figure 64J
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
Atlantic, pelagic.
Figure 64I
With lateral keels over its entire length. Dorsal ribs very slightly pro-
jecting. The posterior portion of the shell is narrow. C. jaleata Pfeffer is
the same species.