SHELLS OF SOUTH AMERICA. 
311. Trocuus MIcROSTOMUS, @’Orb. Voy. v. 410. t. 76. 
£, 20,, 21, 
Chili. 
312. aes Aravucanus, d’Orb. Voy. v. 410. t. 55. 
. 5-8. 
Chili. 
313. Trocuus Matournus, d’Orb. Voy. v. 411. 
Falkland Islands. 
A species of Margariia. 
314. DELPHINULA CANCELLANA, Gray, d’Orb. Voy. v. 
41] 
Arica. 
315. Turso nicer, Gray, d’Orb. Voy. v. 411. t. 55. 
f. 9-11, 
Chili. 
Fam. 8. IANTHINID. 
316. IANTHINA FRAGILIS, Lamk., d Orb. Voy. v. 413. 
t. 61. f. 8-10. 
Helix Ianthina, Linn. 
Trochus laathina; Chemn. 
Tanthiaa penicephala, Peron. 
Tanthina communis, Lamk. 
Ianthina bicolor, Costa. 
Atlantic Ocean. 
317. IANTHINA PROLONGATA, Blainv., d Orb. Voy. v. 
414. 
Tanthina globosa, Swainson. 
Ianthiva communis, Costa. 
Ianthina niteus, Menke. 
Atlantic Ocean. 
35 
B.M. 
B.M. 
B.M. 
B.M. 
B.M. 
B.M. 
B.M. 
These shells are almost always found in company with each 
other: can they be different sexes of the same species ? 
