Chapman.] 



Pliocene Ostracoda . 



95 



argillaceous sandstone, of a bluish-grey color, yielded only a few 

 separate valves of Ostracoda. 



"No. 589. Wild Cat Canon, one-fourth of a mile south of the 

 Caves." This is* a greenish-grey marl in which occur bands of 

 Ostracod valves thickly massed together. 



" No. 26. East side of San Pablo Ridge, one and three-fourths 

 miles northwest of Orinda Park." A dark, impure-looking lime- 

 stone crowded with Ostracoda very perfectly preserved and stained 

 nearly black. 



"No. 297. Bollinger Canon, twelve miles southeast of Berkeley." 

 A pale ocherous limestone, somewhat friable, and largely composed 

 of the valves of Ostracoda. 



All of the Ostracoda here described are such as inhabit fresh 

 water at the present day, with the exception of Cypridopsis, which 

 is as often found in brackish water. They are comprised in the 

 family of the Cyprid/e. 



It should, however, be borne in mind that in describing Ostra- 

 coda from the carapaces alone, and without any of the soft parts > 

 the determination of species and even genera is more or less pro- 

 visional. 



I will here express my indebtedness to Prof. T. Rupert Jones, 

 who has aided me greatly in regard to points of affinity respecting 

 these specimens, as well as by his generous and invaluable advice 

 throughout the Writing of this paper. 



DESCRIPTIONS. 

 Cypria, Zenker, 1854. 



Cypria subangulata\ sp. nov., plate 3, figs. 1-3. 



Valves subreniform ; greatest height slightly more than half the 

 length. Anterior end broader than the posterior; both rounded, 

 excepting at the antero-ventral region, where the outline forms a 

 blunt angle. The dorsal edge is subangulate a little in front of the 

 middle; the ventral edge slightly sinuous behind the middle. The 

 valves are steeper towards the ventral margin. Length, one-fortieth 

 of an inch ; height, one-seventy-second of an inch. 



