EXPLANATION OF PLATE 5 



Figures approximately natural size. 



Fig. la. Clypeaster howcrsi Weaver. Specimen 10059, Univ. Calif. Coll. 

 Invert. Pal. Upper surface of test. Coyote Mountain, Imperial County, Calif., 

 Univ. Calif, loc. 2064. Lower division of the Carrizo Creek beds. Pliocene. 



Fig. lb. Clypeaster howersi Weaver. Same specimen. Lateral surface of test. 



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