Fig. 1. Psamvwbin californica Conrad; Sunset shell. Monterey Bay. Natural 

 size. Extei-ior of right valve. 



Fig. 2. Sanr/iiiiiohtrUi niittalU Oonrad : Purple flam. Anaheim Slough. Natural 

 size. Exterior of left (upper) valve. 



Fig. 3. Sanr/itiiKilarki niittalli, same specimen as Fig. 2. A'iewed from tlie siphon- 

 ate end. Note greater (•on\'exit.v of the left (tipper) val\-e. 



