Plate 1 



Fig. 1. Pccten circularis Sowerby ; Scallop. Anaheim .Slough. Thi-ee-(iuai-ter;5 

 natural size. Exterior of uppei- (left) \-alve. 



Fig. 2. Pecten circularis, same specimen as Fig. 1. Interior of lower (right) 

 valve. Note the "ears" on either side of the hinge and the marginal teeth that 

 interlock in the closed shell. 



Fig. 3. Hinnites cjUiantcns Gray; Rock scallop. Monterey Bay. Three-quarters 

 natural size. Interior of the lower (right) valve. Note scar of the single 

 (posterior) adrtuetoi' muscle and pallial line without sinus. 



