96 
A11CA carinata. 
TAB, XLIY . — Lower figures * 
Spec. Char. Very convex, parallellipipedalc, anterior 
side flattisb, separated by an acute angle, trun- 
cated at nearly a right angle; posterior side 
rounded; surface longitudinally ribbed. 
Above twice as wide as long; binge straight; beaks 
slightly incurved. The ribs or striae are chiefly alternately 
one rather more prominent than the other ; sometimes on the 
sloping sides there are two faint rising striae intervening. 
The angles, of the usual form of those of Area Noce Linn . 
are very sharp, and the shell not so wide. 
These are from the micaceous sand of the Devizes CanaL 
They are remarkably neat impressions, shewing the direc- 
tion of the hinge teeth, if 1 am not misled by the roughness ' 
of the sand. Mrs. Gent was so obliging as to favour me 
with these, and Thomas Meade, Esq. has assisted me with 
line specimens, from his cabinet. 
