80 CONCHOLOGIA “CHESTRICA, 
Station, Schuylkill River, and Brandywine Creek, 
Chester County ; common. 
Lingual Dentition of A. limosa. — [Stimp.] Opercutum of A. 
Fig, 166, limosa,. — {Sump. } 

A. decisa, HALDEMAN, Mon. Lim., 1842. 
A, decisua. Shell, short, conical, smooth, shining; 
pate whorls 5; base slightly perforated; aperture 
- dilated, semicircular ; color pale green ; slightly 
O translucent. H. 4, W. 2%, mill. 
Station, Brandywine Creek, Chester County ; 
not common. 
A. grana, Say. 
Paludina grana, Say, Jour. Acad. Phila., II., 1822. 
A, granada. 
[W. G. B.] ; 
Fig, 169, Convex, smooth; aperture orbicular, sub-an- 
cular: “umbrlicate: ) Ie) 2, Wo 127 smile 
Station, in ponds, on fallen leaves. Picker- 
ing Creek, Chester County ; abundant. 
Shell, very small, conic-ovate; whorls 5, 
Genus BYTHINELLA, Moguin Tanpon, 1851. 
Shell, elongated-ovate, turreted; umbilicus generally 
closed ; apex obtuse ; aperture oval, or rounded, slightly 
thickened. 
Animal, with the foot rather long, narrow, and round- 
ed behind; tentacles setaceous and pointed; verge bifid; 
the longer branch not coiled about the shorter one; 
operculum sub-spiral; concealing the posterior part of 
the foot. 
