59 



cies having almost the shape of Natica. They can- 

 not be confounded with Pa7i«Zma, because the labium 

 is thickened, the duplication uniting above with the 

 labrum, and the aperture is also acutely angular 

 above. I believe all the species adhere only to cal- 

 careous banks or to stones; never travelling in the 

 •sand like many species of Melania and Paludina. 



ANCULOTUS PR.^ROSUS. 



Plate -yilh— Fig. 13. 



DESCRIPTION. 



Shell suboval, ventricose; spire very short, much 

 eroded at the apex; body whorl contracted near the 

 middle by a broad slight channel; epidermis horn- 

 coloured, with dark angular spots disposed in bands; 

 distinct on the interior of the labrum; base deeply 

 indented behind the columella; columella angulated 

 at base; aperture subovatej acute above. Length 

 three-fourths of an inch. 



Anculotus prcBTOsiis, Say. Journal of the Academy 

 of Natural Sciences, vol. ii. p. 177. 



OBSERVATIONS. 



Inhabits the Ohio and Tennessee rivers. 



I have a variety less ventricose, and without any 

 indentation at base. 



