219 
tendency towards tlie depressed spiral form in tliis sliell, evinced 
by tbe great obliquity of tbe cardinal portion, which hardly pro- 
trudes beyond the margin, would arrange it with the genus Gry- 
plisea in the estimation of some authors a group, however, which 
we consider as a mere subdivision of the present genus. On the 
lower part of the plate is represented one of many specimens 
which I obtained in Florida attached to various obj ects. It seems 
to be closely related to a fossil of Virginia, to which Mr. Conrad 
has given the name 0 . solea, but as my specimen of that shell is 
imperfect and I have not his description, I cannot determine the 
degree of affinity ; it may possibly be a variety of that species. 
I have also a specimen from the Antilles, and another that is re- 
versed. Plate 58. 
Cytherea. — Shell bivalve, equivalve, inequilateral, suborbicu- 
lar, trigonate or transverse ; four cardinal teeth on one valve, three 
of which diverge from the summit and one is isolated, situated 
under the lunule; three divergent cardinal teeth upon the other 
valve, and a fosset at a little distance, parallel to the lunule mar- 
gin ; no lateral teeth. , 
Ohs. A genus of beautiful marine shells, included by Linne in 
the genus Venus, but separated by Lamarck in consequence of the 
middle tooth of the hinge being profoundly divided into two, and 
the posterior tooth being distant and parallel to the lunule edge. 
The name of Meretrix, which that author first applied to this genus, 
he subsequently thought proper to reject in favor of the present 
designation. An allied genus, the Astarte of Sowerby ( Grassina, 
Lam.), has but two teeth in each valve. Cyclas, Gyrena and 
Megadesma have remote lateral teeth ; Gyprina has one remote 
lateral tooth, and the posterior muscular impression of Lucina is 
elongated. 
The species are numerous, inhabitants of almost every shore, 
and are imbedded in many fossil localities. The Japanese and 
Chinese paint and gild the inner side of G. lusoria with vari- 
ous devices, and make use of it in their games of chance, whence 
its name. 
Cytherea albaria. — Desc. Shell transversely oblong-ovate^ 
nequilateral, wrinkles of growth more obvious towards the margin, 
omewhat polished, with a slight appearance of rather broad, nu- 
