79 
CULTELLUS, Schumacher. 
Gen. Char. An equivalved, inequilateral, trans- 
verse, compressed shell, with slightly gaping, 
seldom truncated sides. Hinge-teeth in the 
right valve, two, one longitudinal, erect, the 
other (posterior) oblique, decumbent; in the 
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left valve, three, the central one bifid with 
divaricating apices, fulcrum long, marginal. 
Beaks distant from, but nearest to, the ante- 
rior extremity. Epidermis strong. 
More or less oval, transversely elongated, generally 
shining, tender shells, with the beaks at about one-third the 
width from the anterior extremity. This genus includes 
the shells arranged by De Blainville under the third divi- 
sion of his genus Solenocurtus, and the first section of his 
genus Sole?i. But the characters of the hinge are sufficiently 
alike in all the species we know to connect them, although 
their forms are various. 
CULTELLUS cultellatus. 
TAB. DCXLII. — -Jig. 5—8. 
Spec. Char. Shell elongate-ovate, with obtuse, 
slightly gaping sides, smooth ; beaks one-third 
the width of the shell from the anterior ex- 
tremity, dorsal and basal margins arched; 
