58 
VENUS. 
A. Subcordate. (Plate VII. Fig, 2.) 
B. Orbicular. (Fig. 3.) 
C. Oval, a little angular on the anterior margin. 
(Fig. 4.) 
Shell having the lips incumbent on the anterior 
margin. Hinge with three teeth, all approxi- 
mate, the lateral ones diverging from the apex. 
The area and areola are well defined. In this 
genus the beaks are uniformly, or with very few 
exceptions, turned towards the posterior slope, that 
\^,from the ligament. By this character they are 
distinguished from many of the Tellinse, which 
otherwise resemble them, as well as from some 
species of difierent genera which have no remote 
lateral teeth. 
The first section A. includes all the shells which 
are nearly cordiform, as well those which are fur- 
nished with spines on the circumference of the 
area, as those which are merely wrinkled, striated, 
or smooth. They are very different in external 
