47 
UNIO PEROVATUS. 
Plate II. — Fig, 3. 
DESCRIPTION. 
Shell ovate, rather ventricose, valves thick on the 
anterior side, thinner posteriorly; anterior margin 
regularly rounded; basal margin rounded; posterior 
extremity subangulated; beaks rather elevated, ap- 
proximate, undulated; epidermis olive, wrinkled on 
the margin; cardinal teeth erect and prominent, not 
very thick; nacre white. 
Unto perovatus, nob. Silliman’s Journal, vol. xxv. 
p. 338, pi. L fig. 3. 
OBSERVATIONS. 
The regular ovate form of the shell will distinguish 
it from most other species; the young shell, however, 
is broader behind, approaching to an oval figure, 
and is ornamented with green rays on an olive yellow 
ground. It inhabits small streams in Greene county, 
Alabama. 
ANODONTA TERES. 
Plate YII. — Fig. 2. 
DESCRIPTION. 
Shell narrow-elliptical, inflated; posterior side pro- 
