278 AMERICAN JOURNAL 



DESCRIPTIONS OF AMERICAN FRESH- WATER 

 SHELLS. 



BY T. A. CONRAD. 



PHYSA, Drap. 



1. Physa pomilia, Conrad. — Plate 15, figs. 1, 2, 3. 



Description. — Shell elliptical, thin, translucent; whorls 5, 

 regularly rounded ; spire conical, short; aperture about two- 

 thirds the length of the shell, margin of labrura regularly- 

 rounded; base slightly produced. 



Inhabits Randon's Creek, near Claiborne, Ala. 



Physa pomilia, Conrad.— Amer. Journ, of Science and Arts, 

 Vol. 25, p. 343, 1834. 



ANCULOSA, Say. 



2. Anculosa pumila, Conrad. — Plate 15, fig. 5. 



Description. — Obliquely ovate, spire consisting of one con- 

 vex whorl; apex eroded; color dark olive, almost black; aper- 

 ture obtusely subovate ; base slightly grooved behind the re- 

 flexed labrum. 



Inhabits the Black Warrior River, Ala. 



This small shell is supposed to belong to the family Amni- 

 colidse. 



VIVIPARUS, Lam. 



o. Viviparus geniculus, Conrad. — Plate 15, figs. II, 17. 



Paludina genicula, Conrad. 



Reeve has erroneously referred this very distinct species to 

 V. ponderosa, Say, from which it is readily distinguished by 

 its scalariform spire, and thinness in the substance of the shell. 

 It is more nearly related to V. Integra, Say. 



