68 EARLY TERTIARY OSTRACODA 



corner meets the dorsal margin at an angle (better seen in dorsal view) and ends as an 

 ala at the posterior. A marginal rim runs round the anterior, along the venter and 

 round the posterior margin. 



Dimensions (mm). 



L H W 



Io. 3142 Carapace 0-54 0-32 0-32 



Remarks. Topotype material was not available for study, and it is, therefore, 

 difficult to determine whether or not the Rakhi Nala specimens are conspecific with 

 those from the type locality in Kutch. 



Quadracythere (Hornibrookella) subquadra sp. nov. 



(Plate 34, figs. 6-1 1) 



Derivation of name. Latin subquadrus, almost square ; with reference to the 

 outline in lateral view. 



Diagnosis. Carapace subquadrate with dorsal and ventral margins almost 

 straight and subparallel. Surface strongly and coarsely reticulate. Sexual dimorphy 

 moderate. 



Holotype. Io. 4352, a female carapace (PI. 34, figs, 7, 10, 11). 



Paratype. Io. 4302. 



Material. 41 specimens from the locality below from one horizon (sample 

 no. 24161). GSP BM 2585-6. 



Type locality. Zao River section. 



Type horizon. Upper Chocolate Clays, sample no. 24161. 



Description. Carapace subquadrate in lateral outline with a short caudal process. 

 Anterior margin broadly rounded, posterodorsal slope slightly concave, posterior 

 extremity almost straight, posteroventral margin curved. Dorsal and ventral 

 margins nearly straight and sub-parallel. Greatest height at the anterior cardinal 

 angle, greatest length below the mid-point. In dorsal view the greatest width is 

 situated in front of the middle. Anterior cardinal angle rounded, posterior cardinal 

 angle well-developed. Left valve over-reaches the right valve slightly in the region 

 of the posterodorsal slope and the anterior cardinal angle. Sub central-tubercle 

 prominent, eye-tubercle rounded and distinct. Surface coarsely and deeply reticulate. 

 There is a distinct ventral ridge at some distance from the venter and a short 

 curved hornlike ridge at the posterodorsal corner. Anterior marginal rim prom- 

 inent continuing along the venter and around the posterior margin as a less 

 prominent rim. Anterior margin ornamented with numerous denticles. 



Sexual dimorphism moderate ; the presumed females are wider than the males. 



Dimensions (mm). 



L H W 



Io. 4302 Carapace male o-66 0-40 0-32 



Io. 4352 Carapace female (holotype) 0-67 0-42 0-34 



