139 
CYCLAS. Bruguiere . 
Gen. Char. An equivalved inequilateral bivalve, 
more or less transverse, with the anterior side 
even : hinge strong, with two or three di- 
verging teeth and one or two elongated ones : 
cartilage external. 
An intermediate Genus between Venus and Tellina; 
it has the general form of Venus, with the lateral tooth 
or teeth of Tellina, from which, however, it differs, in 
being straight and less slender. The species do not pre- 
sent much variety of ornament, either in form or colour, 
and in most of them there is no lunula, and the edges are 
entire : several of the recent ones have a strong epidermis. 
Venus Islandioa of Linn, is a Cyclas of Bruguiere; 
this, and one or two analogous fossil shells, which I have 
published as of the Genus Venus,* I still suspect may 
form a new Genus distinguished by the hinge. 
CYCLAS deperdita ? 
TAB. CLXII. — Fig. 1. 
Spec. Char . Ovato-transverse, rather gibbous, 
umbonate ; lines of growth elevated, irre- 
gular : central hinge teeth three, lateral ones 
two. 
Sxn. Cyclas deperdita. Lam . Env. de Paris 252. 
Park . Org. rem. 3. 189 ? 
The form is a short oval, rarely a little angular towards 
the anterior side : two of the central teeth of the hinge 
are slightly bifid : the lateral ones sometimes finely 
striated perpendicularly, as in several others of the 
Genus, f 
This is a common species at Charlton, along with the 
two following, and two or three species of Cerithia, 
forming together a stratum several feet in thickness, in 
* See the Generic character of Venus, p. 125. 
f I have a large species from China that shews the striae very strongly. 
