44 EARLY TERTIARY OSTRACODA 



Description. Carapace subrectangular in lateral view, arrow-shaped in ventral 

 view. Sexual dimorphism rather pronounced ; the females are higher and wider 

 than the males. Anterior margin broadly rounded, posterior slightly subangular, 

 particularly in the right valve. Dorsal margin straight but appears to be convex 

 due to the over-reaching of the dorsal ridge ; ventral margin slightly concave 

 anterior to the middle. Anterior cardinal angle distinct and rounded. Valves 

 almost equal. Eye-tubercle distinct but not high. Subcentral-tubercle distinct, 

 slightly lobate. Surface strongly and deeply reticulate, the reticulation being 

 concentric around the subcentral-tubercle. Four longitudinal ridges occur : the 

 dorsal ridge is convex upwards ; it commences below the eye-tubercle and culminates 

 in the posterodorsal region ; the median or second ridge is also convex upwards ; it 

 runs from the subcentral-tubercle towards the posterior but its continuation anterior 

 to the subcentral-tubercle is not distinct ; the third ridge is convex downwards in its 

 anterior half and slopes obliquely upwards towards the posterior ; the ventral ridge 

 is better seen in ventral view ; it is confined in the posterior three-quarters. Anterior 

 margin denticulate. There is a short posteroventral spine present in most specimens. 

 Radial pore canals simple, more or less straight, irregularly spaced, few seem to 

 bifurcate, about 25-28 in the anterior. Inner margin and line of concrescence 

 coincide throughout. Duplicature moderately wide with a distinct selvage. In the 

 right valve the selvage lies at some distance from the outer margin and the anterior 

 and ventral flange grooves are distinct. Adductor scars in a vertical column of four 

 and with a U-shaped frontal scar. Hinge holamphidont. 



Dimensions (mm). 



L 



Io. 4281 Carapace male 071 



I°- 4335 Carapace female (holotype) 0-71 



Io. 3121 Right valve male 0-76 



Io. 3121 Right valve female 076 



Io. 3120 Right valve female 076 



Comparison. The present species is similar in all characters to Gyrocythere 

 exaggerata sp. nov. but is smaller and with a less well-marked ornamentation. On 

 the other hand, the ornamentation is stronger than in Gyrocythere grandilaevis sp. nov. 

 In both the morphological development and stratigraphical position, G. perfecta falls 

 between G. grandilaevis and G. exaggerata. 



Remarks. G. perfecta has so far only been found in the type locality. 



Genus HERMANITES Puri 1955 

 Type species. Hermania reticulata Puri 1954. 



Hermanites cracens sp. nov. 

 (Plate 22, figs. 11 ; Plate 23, figs. 1-3) 



Derivation of name. Latin cracens, graceful ; with reference to the pleasing 

 curve of the ridges. 



H 



w 



o-39 



0-38 



0-42 



0-42 



0-42 



0-42 



0-42 



— 



0-44 



— 



