166 CO^GBYLIA—DITHYRA. 38. 



The species of this genus arc now confined to such as are com- 

 prehended in the above character. From the Pectunculus they dif- 

 fer, in having the teeth disposed in a straight line. Ihey are in- 

 habitants of rocky coasts, and are generally attached to crevices in 

 the rocks by a filament or byssus which issues from the centre of 

 the upper margin. 



* Margine interno crenulato. 1-4. 

 With the inner margin toothed. 



NoiB. Akca testa ohlongd punetato-decussatd, antice angulaid, margine nu- 

 pero transversim production sinuuto hiante. 

 Shell oblong decussate in a punctured manner, angular at the ante- 

 rior side, with the upper margin transversely elongated sinuous 

 and open. 

 Area Nose. Linn. Syst. Nat. p. 1140. 



Gmelin, Syst. p. 3306. 

 Turton, Linn. Syst. iv. p. 250. 

 Montagu, Test. Brit.p. 139. 

 Pennant, Brit Zool. iv. p. 215. 

 Linn. Trans, viii. p. 91. 

 Donovan British Shells, v. tab. 158, fig. 1, 2. 

 Turton, British Fauna, ji. 161. 

 Dillwyn, Dcscript. Catal. p. 226. 

 Turton, Conch. Diet. p. 9, fig. 58. 

 Chemnitz, vii. p. 177 tab. 53. fig. 529 to 531, 

 Mus cuius striatus. Lister, Conch, tab. 368, fig. 208. 

 Mus. nost. Western coasts and Guernsea. 



