82 EARLY TERTIARY OSTRACODA 



Holotype. Io. 4358, a carapace. 



Material. Only one specimen from the locality and horizon below. 



Type locality. Rakhi Nala section. 



Type horizon. Lower Rakhi Gaj Shales, sample no. 3671. 



Description. Carapace large, elongate, tapering towards posterior and with 

 ventral inflation. Anterior and posterior marginal platforms compressed. Dorsal 

 and ventral margins almost straight, anterior margin broadly rounded, posterior 

 subtriangular. Anterior and posterior cardinal angles well-developed particularly 

 in the left valve. Left valve slightly larger than the right, which it over-reaches in 

 the region of the anterodorsal corner and posterodorsal slope. Eye-tubercle rounded 

 and distinct and lies just below the anterior cardinal angle. Subcentral-tubercle more 

 or less distinct. Greatest height through the anterior cardinal angle, greatest length 

 below mid-point and greatest width a little posterior to the middle. Surface 

 ornamentation consists of reticulations with superimposed papillae. The postero- 

 dorsal process consists of two almost rounded small tubercles (or papillae) joined 

 together in the left valve and one small rounded tubercle in the right. Anterior and 

 posterior marginal rims fairly distinct. Anterior and posterior margins ornamented 

 with a double row of papillae. Internal details unknown. 



Dimensions (mm). 



L H W 



Io. 4358 Carapace (holotype) 1-02 0-51 — 



Comparison. There is no difficulty in separating T. (A.) pedigaster sp. nov. from 

 other described species of the subgenus Acanthocythereis by its large carapace and 

 subtriangular posterior. 



Trachyleberis (Acanthocythereis) postcornis sp. nov. 

 (Plate 41, figs. 9, 10; PI. 42, figs. 1, 2, 7, 10) 



Derivation of name. Latin post, posterior + cornis, horned ; with reference to 

 the posterodorsal process. 



Diagnosis. A species of the subgenus Acanthocythereis with distinct subcentral- 

 tubercle and eye-tubercle. Surface reticulate with small superimposed spines. 

 Posterodorsal process divided into two spines. 



Holotype. Io. 4361, a male carapace (PI. 42, figs. 1, 2, 7, 10). 



Paratypes. Io. 4309+3162-4. 



Material. 45 specimens from the locality below from two horizons (sample 

 nos. 3498 and 3499) and 3 specimens from the Zao River section from two horizons 

 (sample nos. 24131 and 24148). GSP BM 2600. 



Type locality. Rakhi Nala section. 



Type Horizon. Lower Chocolate Clays, sample no. 3499. 



Description. Carapace elongate, subrectangular in lateral outline with dorsal 

 and ventral margins straight, tapering towards the posterior. Anterior margin 



