62 EARLY TERTIARY OSTRACODA 



Description. Strongly dimorphic, the females are less elongate than the males. 

 Carapace subrectangular in lateral view. Anterior broadly rounded, posterodorsal 

 slope very slightly concave, posteroventral margin rounded, dorsal margin almost 

 straight, appearing irregular in lateral view, ventral margin slightly concave anterior 

 to the middle. Right valve slightly over-reaches left valve at the anterior margin 

 but is over-reached by the latter in the region of the posterodorsal slope. Anterior 

 and posterior cardinal angles well-developed, particularly in the right valve. Eye- 

 tubercle rounded and prominent, projecting out from the eye-socket. Subcentral- 

 tubercle distinct. Surface reticulate with superimposed papillae, posterodorsal 

 process either a small more or less rounded tubercle or a cluster of short spines ; ventral 

 ridge present but not elevated. Anterior and posterior marginal rims distinct. 

 Anterior margin denticulate, posteroventral margin papillose. Internal details not 

 observed. 



Dimensions (mm). 



L H w 



Io. 4346 Carapace male (holotype) 0-56 0-32 0-25 



Io. 4298 Carapace female 0-55 0-32 0-29 



Comparison. Phalcocythere rete sp. nov. is larger than the present species, has a 

 less papillose surface and slightly convex dorsal margin in the female. 



Remarks. So far only known from the Rakhi Nala section. The posterodorsal 

 process varies; in some specimens it is almost a rounded tubercle but in others it is a 

 short spine. 



Phalcocythere dissenta sp. nov. 

 (Plate 32, figs. 11-18) 



Derivation of name. Latin dis, not -f- sentus, spiny. 



Diagnosis. A reticulate species of the genus Phalcocythere with dorsal and ventral 

 margins sub-parallel, anterior rim ornamented like a scallop or flute, subcentral- 

 tubercle prominent, eye-tubercle and ventral ridge distinct. 



Holotype. Io. 4343, a male carapace (PL 32, figs. 11, 14, 18). 



Paratype. Io. 4299. 



Material. Approximately 400 specimens from the locality above from six 

 horizons (sample nos. 3454, 3456, 3460 to 3462 and 3464) and 6 specimens from the 

 Zao River section from one horizon (sample no. 24107). GSP BM 2577-8. 



Type locality. Rakhi Nala section. 



Type horizon. Shales with Alabaster, sample no. 3456. 



Description. Sexual dimorphism marked, the presumed males are more 

 elongate, less high and less wide than the females. Carapace sub-rectangular in lateral 

 outline with sub-parallel dorsal and ventral margins. Anterior margin broadly 

 rounded ; posterodorsal slope more or less straight ; posteroventral margin rounded ; 

 dorsal margin slightly convex particularly in the female ; ventral margin almost 

 straight, although partly hidden by the ventral ridge in lateral view. Greatest 



