160 COCHYLIA—DITHYRA. 37. 



37. CYTU ERE A— LAMARCK. 



Testa snhorhicularis seu transversa, tequivalvis, hiesquilateralis, 

 clausa. Cardo valvte dextrce dentibus quatuor, tribus basi 

 approximatis, unico remotiusculo sub areold; valvce sinistrcB 

 dentibus tribus, rarius quatuor, basi approximatis, cum J'oved 

 antica remotiusculd^ : lateralibus nullis. Lioamentum externum. 



Shell somewhat orbicular or transverse, equivalve, inequilateral, 

 with four teeth in the right valve, three of them close together 

 at the base, and one remote under the areola ; in the left valve 

 three teeth, rarely four, close together at the base, with a 

 remote hollow on the anterior side : lateral teeth none. Liga- 

 ment external. 



From the Venus tribe this family is separated by sufficiently 

 distinctive characters: the four teeth in one or both the valves; 

 and when there are but three in Oisie valve, a remote oval hollow 

 parallel with the margin. All the Erilish species, as far as they 

 are yet known, have the internal margin very entire. 



Chione, Cytherea testA ovato-cordatd nitidd transvcrsim substriatd, 

 *• areold lanceolata. 



Shell oval heart-shaped glossy and slightly striate transversely/ 

 with the areola lanceolate. 



Tab. nost. 8, fig. 11. 

 Venus Chione. Linn. Syst. Nat. p. 1131. 

 Gmelin, p. 3272. 

 Turton, Lin. Syst. iv. p. 222. 

 Pennant, Brit Zool. iv. p. 206. tab 54, fig. 2. 



