H 



W 



o-37 



0-32 



o-39 



o-34 



24 EARLY TERTIARY OSTRACODA 



Type locality. Rakhi Nala section. 



Type horizon. Green and Nodular Shales, sample no. 3403. 



Description. Sexual dimorphy rather apparent ; the males are longer in pro- 

 portion than the females. Carapace subtriangular in lateral view. Dorsal margin 

 gently convex, ventral margin almost straight, anterior margin broadly rounded, 

 posterior with a caudal process. Greatest length lies below mid-point, greatest 

 height at anterior cardinal angle. Anterior and posterior cardinal angles more or 

 less rounded, somewhat better developed in the left valve. Left valve very slightly 

 larger than the right valve, over-reaching it in the anterodorsal corner and postero- 

 dorsal slope. Siibcentral-tubercle indistinct. Eye-tubercle distinct but low. Surface 

 reticulate, the reticulae being arranged in lines separated by longitudinal ribs. 

 Anterior marginal rim ornamented with seven small rectangular depressions like a 

 scallop or bivalve mollusc. Internal characters not observed. 



Dimensions (mm). 



L 

 Io. 4271 Carapace male 0-66 



Io. 4320 Carapace female (holotype) 0-66 



Comparison. " Anommatocy there " confirmata sp. nov. differs from the present 

 species by having a thick-shelled and ventrally inflated carapace, a convex rather 

 than straight ventral margin in lateral view, and no ornamentation of the anterior 

 rim. 



Remarks. Specimens from the Shales with Alabaster show fainter longitudinal 

 ribs. This is perhaps due to the form of preservation. 



" Anommatocythere " confirmata sp. nov. 

 (Plate io, figs. 11, 12 ; Plate n ; Plate 12, figs. 1, 2) 



Derivation of name. Latin confirmatus, " strengthened " ; with reference to 

 the variation in the strength of the longitudinal ribs. 



Diagnosis. Carapace ventrally inflated and with a short caudal process. Ventral 

 longitudinal ribs are curved and better developed. Anterior and posterior cardinal 

 angles well-marked. 



Holotype. Io. 4319, a male carapace (PL 10, figs. 11, 12) ; (PI. n, figs. 1, 2) 



Paratype. Io. 4272 + Io. 3102-3. 



Material. 70 specimens from the Rakhi Nala section from five horizons (sample 

 nos. 3499, 3611, 3613-3615). 53 specimens from the Zao River section from six 

 horizons (sample nos. 24145, 24147, 24148, 24150 to 24152). GSP BM 2523-4. 



Type locality. Rakhi Nala section. 



Type horizon. Upper Chocolate Clays, sample no. 3611. 



Description. Sexual dimorphism rather marked, the females are shorter and 

 wider in proportion than the males. Carapace plump, thick-shelled and with ventral 

 inflation. Dorsal margin slightly convex particularly in the right valve, ventral 



