REPORT ON THE PTEROPODA. 
83 
Station 85, July 19, 1873 ; off Palma Island (Canaries); lat. 28° 42' N., long. 18° 6' 
W.; depth, 1125 fathoms; bottom, volcanic mud. 
Station 185, August 31, 1874; off Paine Island; lat. 11° 35' 25" S., long. 144° 2' 0" 
E.; depth, 135 fathoms; bottom, coral sand. 
*6. Cctvolinia tridentata (Forskal). 
1773. Anomia tridentata, Forskal, Descriptiones animalium quae in itinere orientali observavit, 
p. 124. 
1791. Cavolina natans, Abildgaard, Nyere Efterretning om det Skaldyr som Forsk&l bar 
beskrevet under Navnet Anomia tridentata, Skriv. naturhist. Selsk., 
Bd. i., Heft 2, pi. x. 
1801. Hyalsea cornea, Lamarck, Systeme des animaux sans vertebres, p. 140. 
1804. Hyalxa papilionacea, Bory de St. Vincent, Voyage dans les quatre principales lies des 
mers d’Afrique, t. i. p. 137, pi. v. fig. 1. 
1810. Hyale teniobranche, Peron et Lesueur, Histoire de la famille des Mollusques Ptcropodes, 
Ann. Mus. Hist. Nat. Paris, t. xv., pi. ii. fig. 13. 
1813. Hyalsea peroni, Lesueur, Memoire sur quelques animaux mollusques, &c., Nouv. Bull. 
Soc. Philom., t. iii. p. 284. 
1813. Hyalxa chemnitziana, Lesueur, Ibid., p. 284. 
1816. Hyalxa australis, Peron, Voyage de decouvertes aux terres australes, t. i., pi. xxxi. fig. 5 
( sine descriptions). 
1821. Hyalxa forslahlii, Lesueur, MS., in de Blainville, Hyale, Diet. d. Sci. Nat., t. xxii. p. 79. 
1836. Hyalxa affinis, d’Orbigny, Voyage dans l’Amerique meridionale, t. v. p. 91, pi. v. 
figs. 6-10. 
1848. Hyalxa truncata, Krauss, Siidafricanische Mollusken, p. 34, pi. ii. fig. 12 ( non Lesueur). 
1859. Cavolinia tdemus, A. Adams, On the Synonyms and Habitats of Cavolinia, Diacria and 
Pleuropus, Ann. and Mag. Nat. Hist., ser. 3, t. iii. p. 44. 
1877. Hyalxa cumingii, Sowerby, in Reeve, Conckologia iconica, t. xx., Pteropoda, fig. 5. 
For description and figures see Boas, Spolia atlantica, p. 115, pi. i. fig. 8; pi. ii. 
% 19 - 
It is not possible to maintain the specific distinctness of “ Hyalsea affinis,” d’Orbigny, 
and Cavolinia tridentata ; the two forms merge into one another (Boas, Spolia atlantica, 
pi. vi. fig. 100). 
Habitat. — Atlantic Ocean ; from 39° 53' N. (Verrill) to the latitude of the Cape of 
Good Hope, towards both Old and New Worlds ; Mediterranean. 
Indian Ocean; from 5° N. to about 40° S., from the coast of Africa (Zanzibar) to 
Australia. 
Pacific Ocean ; western portion, Yellow Sea (British Museum), China Sea (Boas), 
Malay Archipelago (Borneo, &c.) (Gray), lat. 13° N., long. 156° E. (“Vettor Pisani ” 
Expedition); South-east Pacific to 37° S. (Knocker). 
Challenger Specimens. — I. Living specimens. 
Station 241, June 23, 1875; Yokohama to Sandwich Islands; lat. 35° 41' N.. 
long. 157° 42' E. 
