110 PNEUMONOBRANCHIATA. 



3. Testacella. Shell ear-shaped, on the hinder part 

 of the body. (p. 103. f. 4, 5.) 



* * Body granular, without any grooves ; lips short, 

 compressed. (Helicina.) 



4. Helix. Shell subglobose or depressed ; mouth 

 semilunar ; peristome rather thickened and re- 

 flected, (p. 103. f.6.) 



5. Zonites. Shell depressed; mouth semilunar; 

 peristome thin, acute. 



6. Succinia. Shell oblong, elongate ; mouth very 

 large, oblong ; peristome thin. 



7. Bulimus. Shell oblong, elongate, striated ; 

 mouth moderate, ovate, toothless. 



8. Zua. Shell oblong, elongate, polished ; mouth 

 moderate, ovate, with a thickened internal edge. 



9. Azeca. Shell oblong, elongate; mouth mode- 

 rate, toothed, with a thickened internal edge. 



10. Achatina. Shell turreted, elongate; mouth 

 ovate ; inner lip truncated in front ; peristome 

 thin. 



1 1 . Pupa. Shell cylindrical, blunt ; mouth sinuous ; 

 peristome reflected. 



12. Vertigo. Shell cylindrical, blunt ; mouth 

 toothed ; peristome thickened behind. 



13. Balea. Shell fusiform, elongate ; mouth ovate, 

 clausium none. 



1 4. Clausilia. Shell fusiform, elongate ; mouth 

 toothed, with an elastic clausium. (p. 103. f, 7.) 



