628 APPENDIX. * 



Species of Brochina. 

 glabra, Mont. glabriformis, Cpr. 



Genus MEIOCERAS, Carpenter. 



Operculum spiral, concave externally. 



Shell in the young state loosely spiral ; when adult often 

 inflated ; aperture oblitme. 



Species of Meioceras. 



cornu-bovis, Cpr. nitidum, Bean. 



cornu-copia, Cpr. 



Vol. i. p. 356. Genus SIPHONIUM. 



Mr. P. P. Carpenter, in his " Catalogue of Mazatlan Mol- 

 lusca," has made a sub-genus of Siphonium, under the following 

 name. 



Sub-gen. aletes, Carpenter. 



Operculum slightly concave, multispiral, often irregularly 

 formed. S. centiquadrus and margaritarum are examples. 



In the typical species of Siphonium the operculum is strongly 

 concave and scarcely spiral, and the species are found in the 

 Atlantic Ocean and Eastern Seas, while those of Aletes are from 

 the Western Hemisphere. 



Vol. i. p. 368. Genus CRYPTA. 

 Sub-gen. garnotia, Gray. 



Shell convex; apex sub-central; inner lip deep within the 

 cavity, shelving downwards in front. C. Solida is an ex- 

 ample. 



