48 
THE YOYAGE OE H.M.S. CHALLENGER. 
Key to the Species. 
I. Shell entirely destitute of transverse grooves. 
1. Shell at its initial portion of a dark brown colour. 
A. Shell with a very marked and somewhat abrupt dorsal curve, and with 
the transverse diameter increasing rapidly at the point of curvature, 1. Clio virgula. 
B. Shell with a slight curvature, and with, the transverse diameter 
increasing uniformly, . . . . . .2. Clio conica. 
2. Shell straight, much elongated, with the initial extremity of a whitish 
colour, . . . . . . . . .3. Clio acicula. 
II. Shell with transverse grooves all over its broader portion, . . . .4. Clio chierchix. 
# 1. Clio ( Creseis ) virgula (Rang). 
1828. Creseis virgula, Rang, Notice sur quelques Mollusques nouveaux du genre Cleodora, &c., 
Ann. d. Sci. Nat., ser. 1, t. xiii. p. 316, pi. xvii. fig. 2. 
1829. Creseis unguis, Eschscholtz, Zoologischer Atlas, Heft iii. p. 17, pi. xv. fig. 4. 
1829. Creseis cornucopix, Eschscholtz, Ibid., p. 17, pL xv. fig. 5. 
1829. Creseis caligula, Eschscholtz, Ibid., p. 18, pi. xv. fig. 6. 
1836. Hyalxa corniformis, d’Orbigny, Voyage dans l’Am4rique meridionale, t. v. p. 120, pi. viii. 
figs. 20-23. 
1850. Styliola virgula, Gray, Catalogue of the Mollusca in the Collection of the British 
Museum, pt. ii., Pteropoda, p. 17. 
1850. Styliola corniformis, Gray, Ibid., p. 18. 
1852. Cleodora virgula, Souleyet, Voyage de la Bonite, Zoologie, t. ii. p. 196, pi. viii. 
figs. 18-25. 
1852. Cleodora munda, Gould, The Mollusca and Shells of the U.S. Exploring Expedition, 
p. 489, pi. Ii. fig. 607. 
1852. Cleodora placida, Gould, Ibid., p. 489, pi. Ii. fig. 606. 
1852. Cleodora falcata, Gould, Ibid., p. 490, pi. Ii. fig. 608. 
1879. Cleodora flexa, Pfeffer, Bericht fiber die von S. M. Schiff “Gazelle” und Dr. Jagor 
gesammelten Pteropoden, Monatsher. d. k. preuss. Akad. d. Wiss. Berlin, 
1879, p. 241, figs. 15, 16. 
For description and figures I refer to Souleyet, loc. cit. (see the synonymy above). 
Habitat . — Atlantic Ocean, from 41° 25' N. (Verrill) to 35° 10' S. (Boas), both 
towards the new and the old world. 
Indian Ocean ; from the Gulf of Bengal to 29° S., especially towards the west (south- 
east of Arabia, Blanford) to 65° E. 
Pacific Ocean: eastern portion, from 35° N., about the Bay of Yedo (“Galathea” 
Expedition), to 32° S., New South Wales (British Museum), China Sea (“Galathea” 
Expedition), Coral Sea (Pfeffer); central portion, from 24° N. (“ Vettor Pisani” 
Expedition) to 30° S. (Knocker); North-east Pacific (Gould as “Cleodora falcata”); 
South-east Pacific, Juan Fernandez Island (d’Orbigny). 
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