202 GO^GRYLl A— DITHYRA. 44. 



discrepans. MoDiOLA testd ovatd depressd, antice rotundatd, umbonibus subtermin- 

 alibus, extremitatibus longitudinalitSr costulatis. 

 Shell oval flattish, rounded at the anterior side, beaks not quite ter- 

 minal, and slightly ribbed longitudinally at both ends. 

 Montagu, Test. Brit. p. 119. and 

 Suppl. p. 65, tab. 26, fig. 4. 

 Turton, British Fauna, p. 164. 

 Linn. Trans, viii. p. iii. tab. 3, fig. 9. 

 Pennant, Brit. Zool. iv. p. 241. 

 Dillwyn, Descript. Catal. p. 319. 

 Turton, Conch. Diet. p. 112. 

 Mus. nost. Western and Irish Coasts. 



Shell marked like the last, but is much flatter, broader and 

 rounder at the end opposite the hinge, where the ribs are only eight 

 in number : the beaks are more pointed and not quite terminal ; 

 and the color is usually of a more opake brown. 



45. OSTREA— L/iVA^E. 



Testa fixa, inaquivalvis, irregularis ; umbonibus subdivaricatis, cetate 

 inosqaalibus. Cardo edentulus, fossuld semiexternd estate gradatim 

 elongatd in valvd inferiori. Ldgamentum internum. 



