REPORT ON THE PTEROPODA. 
41 
Family II. Cavoliniida 
1841. Hyalidc e, d’Orbigny, Mollusques de Cuba, t. i. p. 70. 
1842. Cavolinidse, d’Orbigny, Paleontologie frai^aise, Terrains ere faces, t. ii. p. 4. 
1842. Cleodoridse, Gray, Synopsis of the Contents of the British Museum, p. 92. 
1869. Cliidse, Jeffreys, British Conchology, vol. v. p. 118 (non Woodward, 1856). 
1875. Orthoconques, Fol, Sur le developpement des Pteropodes, Archives d. Zool. Exper., ser. 1, 
t. iv. p. 177. 
incl. Cuvieridx, Gray, 1842 = Tripteridx, Gray, 1850. 
Characters. — Shell external, calcareous, inoperculated, bilaterally • symmetrical, not 
rolled up in a spiral, but at its apex often dorsally recurved. Animal with its pallial 
cavity ventral, and its columellar muscle dorsal ; the anus situated on the left. 
Description. — The shell has a variable form, which may always be referred to a 
hollow cone, more or less modified, flattened dorso-ventrally or circular in section. The 
apex is quite straight, recurved or truncated ; the mouth broad or narrow ; with longi- 
tudinal or transverse ribs, &c. The initial portion of the shell is generally distinct from 
the rest, and represents the embryonic shell. 
The animal may be entirely retracted within the shell. The form of the fins and of 
the posterior lobe of the foot varies considerably. The mouth, the lips, and the tentacles 
resemble those of the Limacinidae (except Peraclis ). 
In regard to the classification, as in the Limacinidae, we find a large number 
of genera established by too zealous conchologists for the reception of the species be- 
longing to this family. Abstracting genera based on Tertiary fossils, we find seventeen 
different generic titles applied to living Cavoliniidae. These are enumerated in alpha- 
betical order : — 
Archonta, Montfort, 1810. 
Balantium, Benson, 1837. 
Carolina, Abildgaard, 1791 ( non 
Bruguiere, 1792). 
Cleodora, Peron and Lesueur, 1810. 
Clio, Linne, 1767 ( non Muller, 1776). 
Creseis, Bang, 1828. 
Cuvieria, Bang, 1827 (non Peron, 
1807). 
Cuvierinct, Boas, 1886. 
Diacria, Gray, 1842. 
Of these seventeen titles : — 
1. Three alone ought to be preserved as applicable to well-established genera — 
(1) Clio; (2) Cuvierina; (3) Cavolinia. 
(zool. chall. EXP. PART LXV. 1887.) 
Hyalsea, Lamarck, 1801. 
Hyalocylis, Fol, 1875. 
Orhignyia, Adams, 1859. 
Pleuropus, Eschscholtz, 1825. 
Rheda, Humphreys, 1797. 
Styliola, Lesueur, 1825. 
Triclci, Oken, 1815 ( non Betzius, 
1788). 
Triptera, Auctorum (non Quoy and 
Gaimard, 1824). 
Ttt 6 
