70 



labrum sliglitly undulated by the groove, and with a distinct sinti? 

 at the base of the columella. 



Inhabits Ohio River. 



Length, one inch and one tenth. Breadth, 3-5 of an inch. 

 Grreatest transverse diameter more than 2-5. 



Very common at the Falls of the Ohio River. It is probably 

 the largest species of this genus in the United States, and may be 

 readily distinguished from its congeners by its broad groove. 



Melania elevata. — Shell gradually attenuating to the apex, 

 slightly and irregularly wrinkled, olivaceous ; suture not deeply 

 impressed ; volutions nine or ten, with several more or less elevated 

 revolving lines, of which one being more conspicuous gives the 

 shell a carinated appearance ; aperture oblique, equalling the length 

 of the second, third, and fourth volutions conjunctly. 



Length, one inch. Breadth two-fifths. Inhabits Ohio River. 



Distinct from our other species, by the elevated revolving lines. 



Melania Conica. — Shell conic, rapidly attenuating to an acute 

 apex, very slightly wrinkled, olivaceous ; suture not deeply im- 

 pressed ; volutions seven or eight ; aperture oblique, equalling the 

 length of the second, third, and fourth whirls conjunctly. 



Var. a. With from one to three, revolving, rufus or blackish 

 lines. 



Length, nearly 3-5 inch. Of the aperture, I inch. Inhabits 

 Ohio River. 



May be readily distinguished from M. virginica by the much 

 more rapid attenuation of the spire, and in the proportional differ- 

 ence in the length of the aperture, which in the virginica is not 

 more than equal to the length of the second and third whirls. 



MelAnia pr^rosa. — Shell subglobular, oval, horn color; volu- 

 tions three or fOur, wrinkled across ; spire very short, much eroded 

 in the old shell, so much so as to be sometimes not prominent 

 above the body whirl ; body whirl large, ventricose, with a very 

 obtuse, slightly impressed revolving band; aperture suboval, abov€ 

 acute and eifuse ; withip on the side of the exterior lip about four 

 revolving purplish lines, sometimes dotted, sometimes obsolete or 

 wanting ; labium thickened, particularly at the superior tcmiina- 

 tion near the angle, and tinged with purplish ; ba,se of the colum- 

 ella somewhat elongated and incurved, meeting the exterior IJp at 

 an angle. 



