Plate 16 



Fig. 1. DoiK/a- c«7(7onn"c« Conrad ; Wedge shell. Fal.se Bay. Twice natural .size. 

 E.Kterior of left valve. 



Fig. 2. Donax laevigata De.shayes ; Wedge .shell. Mouth of Anaheim Slough. 

 Twice natural size. Exterior of left valve. 



Fig. 3. Scliizothaerus nuttalU Conrad ; Gaper. Elkhorn Slough, Monterey Bay. 

 One-quarter natural size. Exterior of right valve with extended .siphon. Note 

 plates at tip of siphon. 



