56 



the whorls of which are small; apex eroded; body 

 whorl elongated, obtusely rounded above, and at 

 base; aperture more than half the length of the shell, 

 narrow, much contracted above. 



OBSERVATIONS. 



This species is remarkable for the rude, almost 

 deformed whorls of the spire. It inhabits the Tom- 

 beckbe river, on the soft limestone banks, and is ge- 

 nerally coated with a calcareous deposite. 



MELANIA TROCHIFORMIS. 



Plate YlU.—Fig. 11. 



DESCRIPTION. 



Shell short conical, ventricose, turreted;two spiral 

 prominent lines on each whorl, the intervening 

 si)aces concave; summit of the whorls flattened, an- 

 gulated; body whorl angular, with the periphery cari- 

 nated; base flattened; aperture small; labrum angu- 

 lated in the middle^ 



OBSERVATIONS. 



A species easily recognised by its strong ribs, or 

 by its sulci, and its trochiform shape. Inhabits 

 streams in North Alabama. 



