EXPLANATION OF PLATE 56 



All figures approximately natural size 



Fig. 1. Tivela diabloensis, n. sp., var. angulatum, n. var. Eight valve. Lon- 

 gitude, 58 mm. 



Fig. 2. Cyrena (Corbicula) calif ornica Gabb. Eight valve. Longitude, 3 mm. 

 Fig. 3. Tivela gabbi, n. sp. Eight valve. 



Fig. 4. Tivela gabbi, n. sp. Hinge plate of right valve. This specimen 

 shown also on plate 15, figure 2. 



Fig. 5. Paphia staminea Conrad. Longitude, 35 mm. 



[542] 



