EXPLANATION OF PLATE 15 

 All figures approximately natural size. 

 Fig. la. Pinna bicuneata, n. sp. View of right valve of type specimen 11307; 

 from U. C. locality 2284; characteristic of upper San Pablo and Santa Mar- 

 garita. 



Fig. lb. Pinna bicuneata, n. sp. Profile of both valves as viewed from the 

 rear. 



Fig. 2a. Chione semiplicata, n. sp. Exterior view of left valve of type speci- 

 men no. 11318; from U. C. locality 2283; Santa Margarita. 



Fig. 25. Chione semiplicata, n. sp. Interior view of left valve. 

 Fig. 2c. Chione semiplicata, n. sp. View of interior of right valve. 



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