OF CONCHOLOGY. Ill 



oval, almost as large as the wliole shell. Eyes exterior. About 

 four species, fluviatile, lacustrine, and palustrine. " 



There can be no doubt that this description was intended for 

 Ancidosa, Say, as is proved by a MSS. work by Rafinesque 

 (" Conchologia Ohioensis ") in the possession of the Smithsonian 

 Institution, in which there is a rude pen-and-ink drawing of 

 the animal and shell of a Leptoxis. The name has been adopted 

 by Prof Haldeman and others. But as the published descrip- 

 tion refers equally well to Physa or some species of Lymnsea^ 

 and as MSS. authority is not recognized in questions of priority, 

 we are compelled to throw aside this name and adopt that 

 given by Say. 



In the MSS. quoted above, occurs the description of a new 

 genus called Strepoma, together with the figure of a species ; 

 which appears to represent a section of Pleurocera. It is unne- 

 cessary to quote the description, as it was never published : it is 

 only mentioned here because Prof Haldeman adopts it as a 

 generic name in a late paper on the classification of these shells.* 



For the same reason, we do not adopt the genus Amhloxis de- 

 scribed in the American Monthly Magazine, p. 355, 1818 : — 



" Univalve. — Shell thick oboval, mouth oval, rounded at the 

 base, obtuse above, with a thick appendage of the lip, columelle 

 flexuose, a small rugose umbilic. " 



This, the only description, would apply equally well to a 

 Paludina, Anculosa or a Goniohasis of Lea ; and in 1831 (Enum. 

 and Account,) although he renders it plain that he intended the 

 latter, still he does -not adopt the name for his species there de- 

 scribed, and seems disposed to doubt the value of his former 

 division. 



The three following genera were published in Journal de 

 Physique, Bruxelles, tome 88, p. 423 et seq. : — 



" Ellipstoma, Raf. — Shell thick, oval, obtuse. Mouth ob- 

 lique, narrow, elliptic, lips thickened, united, and obtusely 

 decurrent posteriorly. A narrow, oblong umbilicus, half 

 covered by the interior lip. Animal unknown. Fluviatile 

 genus of 4 species, E. r/ibhosa, E. vittata, E. zonalis, and 

 E. marcjlnnla. 



"From the Ohio, Mississippi, &c." 



" Oxytrema^ Raf — Differs from Pleurocera by an oval oblong 

 or ventricose shell, less number of whorls, the last forming 

 nearly the whole ; mouth sharp on both sides, and anteriorly 

 prolonged into a long sharp point. 3 fluviatile species." 



" Camjjehma^ Raf — Shell oval; mouth oval, base truncated, 

 lip reflected, united in a posterior point. No umbilicus. 

 Animal unknown. I have only one species, found in the 



* Proceed. Acad. Nat. Sciences, p. 274, September 18G3. 



