206 CONCHYLIA— DITHYE^. 46. 



quently deformed and distorted by contact with harder objects. It 

 may perhaps be a distinct species ; as it answers to the character 

 given by Lamarck, Hist. Nat. vi. p. 209, to his Ostrea deformis. 



46. PECTEN— L/-Sr£E. 



Testa libera seujixa, suborhicularis, basi transversim auriculafd; um- 

 bonibus contiguis ceqnalibus. Cardo edentulus, fovea interna^ tri- 

 gond. lAgamentum internum. 



Shell free or fixed, somewhat orbicular, transversely dilated into au- 

 ricles at the base; with the beaks equal and close together. 

 Hinge without teeth, with an internal triangular cavity. Liga- 

 ment internal. 



The ear-like appendages at the sides of the beaks distinguish 

 this family from that of the Ostrea. These auricles have generally 

 one of the edges fringed with minute internal crenatures on each 

 side the hinge. They are mostly ribbed longitudinally, and with the 

 exception of Pecten sinuosus and P. Pusio, are free, and capable of 

 considerable locomotion : and they exhibit a more splendid and va- 

 ried display of colors than any of our native genera. 



