. Palæontology ... . il li T Sinclair Sith Philadelphia. PLATE IX. PAGE Fig. 53. Auca sulcicosta. Natural size. 31 53 a. Magnified view of the 54. Yoldia Cooperi. Natural size. 31 From the recent specimen found by Dr. Cooper near Santa 55. Pecten Cerrosensis. 32 One-half natural a. End view to show convexity of the valves. ((SMowiWl Swcxwq of Cttlifonifa. PAJLlSE QJKT 0