ORDER TESTACEA. 113 
covered with an epidermis, and otherwise distinguished from 
the cyclades by having three cardinal teeth. The cyrene 
also inhabit rivers, but there are none in France. (Tell. flu- 
minea, Chemn.) 
CYPRINA, Lam., 
Also separated from the cyclades by Lamarck. ‘The shell is 
thick, oval, with recurved summits, and three stout teeth ; fur- 
ther back is a plate, and under the teeth a large cavity, which 
receives a part of the ligament. (Venus islandica, Chemn., 
&c.) 
GALATHAA, Brug. 
The shell triangular; three teeth on the summit of one 
valve, and two on the other, like a chevron. The lateral plates 
approximated. (Egeria, Roiss.; or Galathea, Brug., &c.} 
But one is known, found in the fresh-water of India. 
It is here also must be placed another genus, separated from 
venus—the 
CorBis, Cuv. FImMBRIA, Megerl. 
Marine testaceous acephala, transversely oblong, which 
have also the stout middle teeth and well-marked lateral 
plates; their external surface is furnished with transverse 
ribs so regularly crossed by rays that it may be compared to 
wicker-work. 
The impression of their mantle exhibiting no flexure, their 
tubes must be short. (Venus Fimbriata, Chemn.) 
Some of them are fossil. In the 
TELLINA, Lin., 
There are in the middle one tooth on the left and two teeth 
on the right, frequently forked, and at the same distance be- 
fore and behind, on the right valve, a plate, which does not 
VOR, Xt. I 
