CONCHOLOGIA CESTRICA. 79 
Family AMNICOLIDA. 
Shell, turbinate, or elongate-turreted, smooth, perfo- 
rate, or umbilicate; peristome continuous; shell often 
covered with blackish incrustations. 
Animal, head proboscidiform, extending beyond the 
foot; tentacles cylindrical, elongated; eyes sessile at 
their outer bases; foot oval, truncated in front, and 
rounded, or pointed, behind; verge exserted, behind 
the right tentacle; operculum corneous, sub-spiral. 
Genus AMNICOLA, GouLtp, and HALprmany, 1840. 
Animal of A.limosa, enlarged. — [Stimpson. ] 
Fig, 164, 

Shell, small, sub-ovate, thin, smooth, perforate; spire 
short; aperture broad-ovate ; peristome continuous. 
Animal, foot short, broad, expanded, and rounded, 
behind, auricled in front; rostrum short; tentacles 
cylindrical, blunt; verge bifid, with a globular base; 
opercle thin, sub-spiral. 
A. limosa, Say. 
Paludina limosa, Say, Jour. Acad. Phila., I., ane 
1817. Fig, 165. 
Shell, conic, sub-umbilicate, dark horn a 
color; epidermis wrinkled; aperture ovate- 
orbicular; suture impressed. H. 3, W. 2, mill. 
