CR USTA CEA—OSTRA CODA . 



369 



Narrower anteriorly than preceding; surface coarsely and rudely 

 spinulose. 



Chesapeakean of Maryland and Virginia. 



129. C. evax Ulrich and Bassler. (Fig. 1670, ^,/.) Mioceni'c. 



Similar to preceding, but spinules fine, more numerous, and 

 with occasional coarser nodes. 



Chesapeakean of Maryland and Virginia. 



Fig. 1670. a, d, Cythere clarkana (i27j, left and ventral views, X 20 ; <:, d^ C. 

 exantJiemata (1-28), interior and exterior of right valve, X 20; e,f^ C. evax (129), 

 right and left, X 20; g-i, C. corniita americana (130), left, right and dorsal of left, 

 X 20 ;/-/, Cytheridea subovata ( 134), dorsal and exterior and inferior of left valve, X 

 20. (Ulrich and Bassler, Maryland Survey.) 



130. C. (Cythereis) cornuta var. americana Ulrich and Bassler. 

 ( Fig. 1 670, g-i. ) Miocenic. 

 Margin with coarse spinules; surface of valve elevated into 



strong, bent, horn-like spine. 



Chesapeakean of Maryland and Virginia. 



131. C. (Cythereis) alaris Ulrich and Bassler. (Fig. 1669, o-^.) 



Miocenic. 

 Margin spinulose; surface of valve with several irregular spines 

 and nodes. 



Chesapeakean of ( ?) Maryland and Virginia. 



132. C.vaughani Ulrich and Bassler. (Fig. 1669, r-^.) Miocenic. 

 Surface coarsely reticulated by longitudinal and vertical ridges. 

 Chesapeakean of Maryland (?) and Virginia. 



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