83 



and E. nanus. He also speaks of live more species, respecting the classi- 

 fication of which he is less certain. 



XLVIII. Achatina. An oval or oblong univalve : the opening en- 

 tire, and longer than wide; the columella smooth, and truncated at 

 its base. 



Bulla achatina, Linn. List. Tab. 579, Fig. 34, is of this genus ; no spe- 

 cies of which is known fossil. 



XLIX. Phasianella. A solid ovate. or conical univalve : the opening 

 longitudinal, ovate, and entire ; with a sharp plain lip : the columella 

 smooth, with an attenuated base. 



The opening of the shells of this genus is almost the same as that of 

 the shells of the preceding ; but the shells of this genus are sea-shells, and 

 are not transparent, but thick. Lamarck describes two species of this 

 genus, which are found among the fossil shells of Grignon : P. turbi- 

 noides and P. scmistriata. 



L. Lymn&a. An ovato-conical, or turreted univalve : the aperture 

 entire and oblong ; the right lip joined to the left, in the lower part rising 

 on the columella, and showing internally an oblique fold. 



The character by which these shells may be distinguished from the 

 Bulimi, is, the very oblique fold on the columella. Helix stagnalis, Linn. 

 List. Tab. 123, Fig. 21, is of this genus. The fossil remains of these 

 shells are very rare. Lamarck has only discovered those of one species 

 in the neighbourhood of Paris, which he names Lymn&a palustris. 



LI. Pyramidella. A turriculated univalve : the opening entire and 

 semioval : the columella projecting, with three transverse folds, and 

 perforated at its end. 



Trochus dolobratus, Linn. List. Tab. 844, Fig. 72, is of this genus; 

 no species of which have been described fossil. 



LII. Melania. A turreted univalve : the aperture entire, ovate, 

 or oblong, and spread out at the base of the columella, which is 

 smooth. 



The shells of this somewhat resemble those of the preceding genus ; 



