PLATE IX. 



>AOB 



Fig. 63. ARCA SULCICOSTA. Natural size. a * 



63 a. Magnified view of the surface. 

 Fig. 64. YOLDIA COOPEEII. .Natural size. 31 



From the recent specimen found by Dr. Cooper near Santa Cruz. 

 Fig. 55. PECTEN CERROSENSIS. 32 



One-half natural size. 

 55 a. End view to show convexity of the valves. 



