ACEPHALA OR LAMELLIBKANCHIATA. 



421 



(Fig. 626), a Clam (Figs. G19 and 636), a Fresh-water 

 Mussel (Figs. G17 and 618), a Scallop (Fig. 622), or some 



FIG. 622. 



FIG. 621. 



An Acephal. Scallop, Pecten varius, L. 



m, pallial curtains ; 6r, brauchi;e. Pecten it-radians. Lam. Reduced. From 



Cape Aim southward. 

 FIG. 623. 



Avicula hinindo, L. Reduced. 

 Mediterranean. 



Milieus vulgaris, Lamarck. 

 China. 



other form ; and a careful study of one will give a general 

 idea of all the ordinary kinds. 



The forms. of Acephala or Lamellibranchiata are very 



