CONCHOLOGY. 105 



P. exigua.* P. fallax.* 



P. armifera.* P. ovata * 



P. pentadon.* 



7. Genus Clatisilia. PI. X. 

 Animal. See Helix. 



Shell. Cylindrical, generally fusiform ; summit obtuse, the 

 last whorl smaller than the preceding ; aperture irregular, rounded, 

 oval ; margin united, and externally reflected. Inhabits dry 

 situations both in Europe and America. Fifteen species. 



Clausilia torticollis. Clausilla denticulata. 



C. truncatula. C. collaris. 



C. retusa. C. papillaris. 



C. costulata. C. plicatula. 



C. corrugata. C. rugosa. 



C. inflata. C. gracilis. 



C. Mediterranea. C. chrysalis. 



C. teres.* 



8. Genus Bulimus. PI. X. 



Jiiiimals of this genus in formation are precisely as the Helix ; 

 they are, however, oviparous, producing eggs with the shell con- 

 taining the animal perfectly matured ; they are frequently as large 

 as a pigeon's egg. 



Shell. Oval, sometimes turriculated, oblong ; the summit of 

 the spire obtuse, and the last whorl larger than all the others 

 together; aperture oblong, oval, edge disunited ; in adults the lip 

 much reflected ; columella smooth, with an inflection in the mid- 

 dle^ the base entire, not channeled. Inhabits mountainous situa- 

 tions in Europe and America ; some beautiful specimens have 

 been found in the woods of Ohio. Sixty-three species. 



Bulimus ovatus. Bulimus multifasciatus. 



B. hsemastomus. B. Bengalensis. 



B. gallina. B. Caribaeorum. 



B. sultana. B. octonus. 



B. zigzag. B. terebraster. 



