394 CALIFOENIA ACADEMY OF SCIENCES. 



EXPLANATION OF PLATE XVL 



Fig-. I. Macoma indenlata Carpenter. Upper San Pedro series, Los Cerritos. Longitude 



50 mm.; natural size. 161 



Fig. 2. Macoma calcarea Gmelin. Lower San Pedro series, Deadman Island. Longitude 



18 mm.; X2.3. i6t 



Fig. 3. Macoma 7iasuta Conrad. Upper San Pedro series, San Pedro. Large, typical 



specimen. Longitude 75 mm.; natural size. 163 



Fig. 4. Macoma hiqidnata Deshayes. Upper San Pedro series, San Pedro. Longitude 



42 mm. ; natural size. 162 



Fig. 5. Macoma secta Conrad. Upper San Pedro series, San Pedro. Longitude 82 mm.; 



natural size. 164 



Fig. 6. Macoma yoldiformis Carpenter. Lower San Pedro series, Deadman Island. 



Longitude 24 mm.; natural size. 165 



Fig. 7. Venus {Chione) gnidia Broderip & Sowerby. Upper San Pedro series, San 



Pedro. Exterior of right valve. Longitude 96 mm.; natural size. 147 



