PLATE 20 
Fig. la. Cardium corbis (Martyn). X 1. Longitude 49 mm. 
Station D5700. Dorsal view. 
Fig. 1b. Cardium corbis (Martyn). XX 1. Longitude 49 mm. 
Station D5700. Exterior of left valve. 
Fig. 2a. Cardium (Protocardium) centifilosum Carpenter. X 2. 
Longitude 10.5 mm. Station D5785.* Exterior of right valve. 
Fig. 2b. Cardiwm (Protocardium) centifilorsum Carpenter. X 2. 
Longitude 10.5 mm. Station D5785.* Exterior of left valve. 
Fig. 2c. Cardiwm (Protocardium) centifilosum Carpenter. X 2. 
Longitude 10.5 mm. Station D5785.* Interior of left valve. 
Fig. 2d. Cardiwm (Protocardium) centifilosum Carpenter. X 2. 
Longitude 10.5 mm. Station D5785.* Interior of right valve. 
Fig. 3. Cuspidaria californica Dall. X 2. Longitude 10 mm. 
Station D 5789. 
Fig. 4. Psephidea ovalis Dall. X 5. Longitude 4.3 mm. Station 
D5788.* Exterior of left valve. 
Fig. 5. Thyasira gouldi (Philippi). X 4 Longitude 7 mm. 
Station D5788.* Exterior of right valve. 
Fig. 6a. Petricola carditoides (Conrad). X 1. Longitude 42.7 
mm. Bolinas. Dorsal aspect. 
Fig. 6b. Petricola carditoides (Conrad). X 1. Longitude 42.7 
mm. Bolinas. Exterior of left valve. 
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