SUBAURICULATED SPONDYLUS. 
Generic Character. 
Animal allied to a Tethys. 
Shell of unequal valves, strong. 
Hinge with tv/o recurved teeth and intermediate 
hollow. 
Specific Character, ^c. 
SPONDYLUS with subauriculated, spinose 
shell. 
Bonann. rear, t 20. 21. 
Seb. mus. 3 . t. 88. f. i—ii. 
The two genera of Spondylus and Chcima, (both 
nearly allied to that of Ostrea,) bear so great a ge¬ 
neral resemblance to each other, tliat, in some species, 
it appears doubtful, at first sight, to which of the 
two the shell should be most properly referred. One 
great particularity however always distinguishes the 
shells of this genus from those of the genus Chama; 
viz. the aspect of the top of the inferior valve, which 
appears exactly as if sawn or cut away by an instru¬ 
ment, so as to leave a flat surface on that part. The 
