55 



obliquely elliptical; less than half the length of the 

 shell. 



OBSERVATIONS. 



Inhabits with the preceding species. The spire is 

 very regularly conical, and the base strongly ribbed. 



MELANIA NASSULA. 



Plate VIII.— M^". 9. 



DESCRIPTION. 



Shell elevated, whorls convex or subangulated, 

 with longitudinal ribs, crossed by numerous spiral 

 elevated lines, about seven on the penultimate whorl, 

 and about eleven on the body whorl; suture impress- 

 ed; apex much eroded. 



OBSERVATIONS. 



Inhabits the limestone spring at Tuscumbia, Ala- 

 bama. Immense numbers of this pretty species con- 

 gregate on the rocks w^here Spring Creek finds a 

 passage through a cavern of the carbonit'erous lime- 

 stone. 



MELANIA CYLINDRACEA. 



Plate YlU.—Fig. 10. 



DESCRIPTION. 



Shell subcylindrical, smooth, with a short spirC; 



