PLATE 30 
Fig. la. Pholadidea ovoidea (Gould). X 1. Longitude 37 mm. 
Bolinas. Exterior of left valve showing siphons extended. 
Fig. 1b. Pholadidea ovoidea (Gould). XX 1. Dorsal view, show- 
ing siphons extended. 
Fig. 2a. Pholadidea ovoidea (Gould). X 1. Longitude 19 mm. 
Ventral view of an immature specimen. 
Fig. 2b. Pholadidea ovoidea (Gould). X 1. View of left valve 
of same specimen. 
Fig. 3a. Pholadidea penita (Conrad). XX 1. Longitude 50 mm. 
Bolinas. Exterior of left valve, showing siphons extended. 
Fig. 3b. Pholadidea penita (Conrad). XX 1. Dorsal view. 
Fig. 4. Sasxicava arctica (Linnaeus). X 2. Longitude 13 mm. 
Station 5700.* Exterior of left valve. 
Fig. 5. Saxicava pholadis Linnaeus. X 1. Longitude 34.6 mm. 
Goat Island, San Francisco Bay, Exterior of left valve. 
[892] 
