EXPLANATION OF PLATE 6 

 All figures approximately natural size 



Fig. 1. Pecten deserti Conrad. Eight valve; from the type locality at Car- 

 rizo Creek, San Diego County; Carrizo formation, Pliocene. 



Fig. la. Pecten deserti Conrad. Left valve; from the type locality. 



Fig. lb. Pecten deserti Conrad. Profile view from the rear of the same 

 specimen as figure la; showing on the left valve ribbing continuing from body 

 over ears without interruption. 



Fig. 2. Pecten proteus, n. sp. Left valve of type from locality 2991; Univ. 

 Calif. 11089; Pecten eoalingensis zone, upper Etchegoin. 



Fig. 2a. Pecten proteus, n. sp. Eight valve; from locality 2991. 



Fig. 2b. Pecten proteus, n. sp. Eight valve; from locality 2991. 



Fig. 2c. Pecten proteus, n. sp. Profile view from rear of same specimen as 

 figure 2; showing unribbed area immediately above ear. 



Fig. 3. Pecten egregius, n. sp. Left valve; from locality 2975; Pecten eo- 

 alingensis zone. 



Fig. 3fl. Pecten egregius, n. sp. Eight valve of type; from locality 2991, 

 no. 11090, Pecten eoalingensis zone, upper Etchegoin. 



Fig. 3b. Pecten egregius, n. sp. Profile view from rear of same specimen 

 as figure 3a. 



Fig. 4. Pecten terminus Arnold. Eight valve; from locality 2523. This 

 species was described as a variety of Pecten estrellanus Conrad by Arnold. 



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