115 



suture, as well as by the more obtusely rounded junction of the 

 labruni with the base, and by the general form. 



Paludina subglobosa. — Shell subglobose ; whorls three and 

 a half, much rounded, rapidly enlarging j suture profoundly im- 

 pressed ; aperture subovate ; umbilicus very narrow, nearly closed 

 by the labrum ; spire very short, convex. 



Inhabits the North-western Territory. Length less than three- 

 tenths of an inch. 



I obtained this shell when traversing the North-western part of 

 the Union. It is much larger than the porata, nob., which it re- 

 sembles considerably, but its whorls are much more rapidly en- 

 larged, and the umbilicus is much narrower. 



Melania simplex. — Shell conic, blackish, rather rapidly at- 

 tenuated to an acute apex ; suture not deeply impressed ; volutions 

 about eight, but little rounded ; apertute longitudinal ; within 

 dull reddish ; labrum with the edge not undulated, or but very 

 slightly and obtusely so near the superior termination. 



Length three-fifths of an inch ; greatest breadth three-tenths. 



For this species we are indebted to Professor Vanuxem, who 

 presented several specimens to the Academy. He informs me 

 that he obtained them in Virginia, in a stream running from Ab- 

 ingdon to the Salt Works, and from the stream on which General 

 Preston's grist-mill is situated, near the Salt Works, as well as in 

 a brook running through the salt water valley, and discharging 

 into the Holstein river. Near the summit the whorls are marked 

 by an elevated line near their bases. 



It cannot be mistaken for the conica, nob., for in that species 

 the aperture is obviously oblique. 



Melania proxima. — Shell conic, rather slender, black, gradu- 

 ally attenuated to the truncated apex ; suture moderately impressed ; 

 aperture longitudinal, within milk white ; labrum with the edge 

 not undulated, or but very slightly, and obtusely so near the supe- 

 rior termination. 



Length to the truncated apex, nearly three-fifths ; greatest 

 breadth less than one-fourth of an inch. 



Professor Vanuxem obtained this species in a small brook 

 which discharges into the Catawba river, near Landsford, Chester 

 district. South Carolina, and also in the Warm Springs, Buncombe 

 county, North Carolina, and in the French Broad river, of the 



