- 
the Family (Quia. ap? + 
_ ‘Schumacher founded his genus Pesca, the cardinal 
ossiculum is in the form of a wedge, placed between the 
dorsal edge and the supports, and the summits are not 
cloven.” M. de Blainville, on the contrary, speaks 
. of and represents them as cloven, and they certainly are 
so in the specimen before me ; the form of the ossicu- 
lum is also semicireular or transverse, instead of cunei- i. 
form. Still, M. Deshayes gives it as a synonym of A. T 
* trapezoides. It would be singular if he were in error 
in this also, and the shell deseribed by M. de Blainville 
and in this paper, should prove: distinct from A. ¢ra- 
pezoides, the CorguLa of Bruguiére’s plate 230, fig. 6, 
a, b, which figure certainly countenances, in a degree, 
this supposition. This must, however, be decided 
elsewhere. I have: here taken the TERAN of M. 
'eshayes as correct. : 
PUDE ES | bel 
= Cask Osreopesma, Deshayes. 
aa 
| E NERIC Cuaracters. Shell oblong, transve se, 
S ges trial thin, inequivalve, slightly gaping at its e 
i Hinge linear, having on each valve a v 
_apophysis, firmly adherent along the superior or 
orsal edge of the valves; a quadrangular ossiculum is 
supported ween these apophyses by the ligament, to 
sk x - "which it-adheres by all its. upper surface. Muscular 
Sn b E small, the anterior elongated, the posterior 
PAi p sion excavated posteriorly. 
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