42 
THE VOYAGE OF H.M.S. CHALLENGER. 
2. Three designate well-marked subgeneric divisions of the genus Clio — 
(1) Creseis ; (2) Hyalocylix ; (3) Styliola. 
3. One represents the young state of some Cavolinia : Pleuropus. 
4. Finally, the ten remaining titles may be preserved as synonyms of the three 
genera — 
Balantium, 
Cleodora, 
Cuvieria, 
Triptera, 
= Clio . 
= Cuvierina . 
Arehonta, 
Diacria, 
Hyalsea, 
Orbignyia, 
Rheda, 
Tricla, 
I 
= Cavolinia. 
For the distinctive characters of the three genera Clio, Cuvierina, and Cavolinia, I 
refer to the synoptic table of genera (p. 8). 
Clio, 1 Linne. 
1756. Clio, Browne, The Civil and Natural History of Jamaica, p. 386. 
1767. Clio, Linne, Systema naturse, ed. 12, t. 1, pt. 2, p. 1094 ( non O. F. Muller, 1776). 
1810. Cleodora, Peron and Lesueur, Histoire de la famille des Mollusques Pteropodes, Ann. Mus. 
Hist. Nat. Paris, t. xv. p. 66. 
1825. Styliola, Lesueur, MS., in de Blainville, Manuel de Malacologie, p. 655. 
1828. Creseis, Rang, Notice sur quelques Mollusques nouveaux appartenant au genre Cleodora, 
et 4tablissement et monographie du sous-genre Creseis, Ann. d. Sci. Nat., s4r. 
1, t. xiii, p. 302. 
1837. Balantium, Benson, Notice on Balantium, a Genus of the Pteropodous Mollusca, Journ. 
Asiat. Soc. Bengal, vol. vi. p. 151. 
1875. Hyalocylis, Fol, Sur le developpement de Pteropodes, Archives d. Zool. Exper., t. iv. 
p. 177. 
To the Thecosomata which I have united in this genus several generic titles have 
been applied, as may be seen from the synonyms. 
Besides these generic titles, we have to note a considerable number of specific 
designations, of which only a very small fraction can be retained as applicable to really 
existing species of the genus Clio. 
After abstracting all the so-called forms of Clio which are really Gymnosomata (see 
the first part of this Report), 2 there remains the following formidable list of specific 
titles attributed to living species. A certain number of extant species are also 
1 Mythological name. 
2 Zool. Chall. Exped., part lviii. pp. 44, 45. 
