ANATOMY OP ACHATINID^E. 



XV11 



(1) Lateral teeth bicuspid, without an entocone: genera 

 Pseudoglessula, Chilonopsis, Riebeckia. The last has a tri- 

 cuspid central, the other two have it unicuspid. 



(2) Lateral teeth tricuspid; genera Homorus, Bocageia, 

 Rumina. All have side cusps on the centrals. 



All known details of the soft anatomy of these genera may 

 be found in the text, under the several generic heads. 



The apex of the shell is usually globose (figs. 1-5), as 

 Homorus, Rumina, etc., in the Old World, and Stenogyra in 

 America; but in some forms it is conic or trochoidal (figs. 7, 

 8) , as in the African Bocageia and the South American Neo- 

 beliscus. 



Figs. 1, 2, Homorus eyanostoma. 3, 4, H. pattalus. 5, H. opeas. 



6, Pseudoglessula prestoni. 7, Bocageia (Petriola) clavus. 



8, B. (P.) aratispira. 9, Pseudoglessula prestoni. 



Key to genera of Stenogyrina contained in Vol. XVII. 



a. Apex of the trochoidal or conic type (figs. 7, 8). 



Columella not truncate in fully adult shells, truncate 

 in the young. Genus BOCAGEIA, p. 216. 



Columella conspicuously truncate (figs. 7, 8). 



Petriola, p. 216. 



