GASTEROPODA. 293 
Shell rimate or perforate, cylindrical or oblong; aperture 
rounded, often toothed ;* margins distant, mostly united by a 
callous lamina. 
Animal with a short foot, pointed behind; lower tentacles 
short. 
Distribution, 236 species. Greenland, Europe, Africa, India, 
Pacific Islands, North and South America. 
Fossit, 40 species. Carb. America. (Dawson.) Hocene—. 
Europe. 
Sub-genus. Vertigo, Mull. V. Venetzi, Pl. XII., Fig. 17. 
Shell minute, sometimes sinistral. 
Animal with the oral tentacles rudimentary or obsolete. 12 
species. Old World. 
Spiraxis, C. B. Adams, 1850. 
Type, Achatina anomala, Pfeiffer. 
Shell ovate-oblong, fusiform, or cylindrical; last whorl 
attenuated; aperture narrow, right margin usually inflected, 
columella more or less contorted, base scarcely truncated, fur- 
nished with a deeply-entering callous lamina. 
Distribution, 80 species. West Indies, Mexico, Juan Fer- 
nandez. 
Stenogyra, Shuttleworth, 1854. Shell elongated, turreted, 
many-whorled, semi-transparent, and blunt at the apex; perl- 
stome simple; shell frequently decolated. 
Animal somewhat like Bulimus; middle rachidian teeth small. 
Distribution, 50 species. Tropical America. 
UYLINDRELLA, L. Pfeiffer. Cylinder-snail. 
Type, C. cylindrus, Pl. XII., Fig. 20.+ 
Synonyms, Brachypus, Guild. Siphonostoma, Sw 
Shell cylindrical or pupiform, sometimes sinistral, many- 
whorled, apex of the adult truncated, aperture round, peristome 
vontinuous, expanded. 
Animal similar to clausilia ; foot short, oral tentacles minute. 
Distribution, 143 species. "West Indies, Mexico, Texas, South 
America. 
BAtbA, Prideaux. 
Type, B. perversa. Pl. XII., Fig. 21. 
Synonym, Fusulus, Fitz. 
* Dr. Pfeiffer terms those teeth parietal which are situated on the body-whorl, those 
on the outer lip palatal, and on the inner lip columeillar. 
t The figure is taken from a specimen in Mr. Cuming’s cabinet, in which the 
empty apex. usually decollated, remains attached to the adult shell, 
