202 CONCHYLIA— D/rJirJRJ. 41. 



discrepaus. MoDioLA testd ovatd dept'cssd, antice rotundatu, nmbonihus 

 subterminalihns, extremitatibns longitudinaliler costulatis. 

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



terminal, and slightly ribbed longitudinally at both ends. 

 Mytilus discrepans. 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. 

 DUlwyn, Descript. Catal. p. 319. 

 Turton, Conch. [)ict. p. 112. 

 Mus. nosl. 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 ter- 

 minal ; and the color is usually of a more opake brown. 



45. OSTB.es.— LINNE. 



Testa fixa, ineequivalvis, irregularis ; umhonihns subdirari- 

 catis, atate ineequalibus. Cardo edentulus,fossuld semiexter- 

 nd ^tate gradatim elongatd in valvd inferiori. Ligamentum 

 internum. 



