46 EARLY TERTIARY OSTRACODA 



coarsely reticulate with prominent subcentral-tubercle from which a ridge runs 

 towards anterior margin. 



Holotype. Io. 4338, a male carapace (PI. 23, figs. 4-7). 



Paratype. Io. 4285. 



Material. 13 specimens from the Rakhi Nala section from six horizons (sample 

 nos. 3499, 3610, 3613 to 3615 and 3618). Two specimens (including holotype) from 

 the Zao River section from two horizons (sample nos. 24148 and 24150). GSP BM 

 2552-3- 



Type locality. Zao River section. 



Type horizon. Upper Chocolate Clays, sample no. 24148. 



Description. Sexual dimorphy observed ; the males are longer in proportion 

 than the females. Carapace thick-shelled, sub-rectangular in lateral view. Anterior 

 margin broadly and evenly rounded, posterior slightly subtriangular. Dorsal and 

 ventral margins almost straight. Valves more or less equal. Anterior cardinal 

 angle well-developed. In dorsal view, greatest width lies in the posterior third. 

 Eye-tubercle rounded and prominent with rounded deep groove in front (better seen 

 in dorsal view). Subcentral-tubercle prominent with a ridge running towards the 

 anterior margin. Surface strongly reticulate (occasionally with superimposed 

 rounded spines particularly at the junction where two reticulae meet). Dorsal and 

 ventral ridges well-developed : the dorsal ridge is almost straight while the ventral 

 ridge is curved convexly downward in the middle culminating in a short vertical 

 ridge in the posterior third. Anterior and posterior marginal rims elevated, ventral 

 marginal rim somewhat less elevated. Anterior and posterior margins ornamented 

 with double row of spines (not preserved in all specimens) — one row of spines lies on 

 the anterior and posterior marginal rims and the second row below these rims. 

 Duplicature of moderate width with subperipheral selvage. Radial pore canals and 

 muscle scars not known. Hinge holamphidont : left valve hinge consists of two 

 terminal sockets, median element subdivided into anteromedian subcorneal pro- 

 jecting tooth and denticulate bar ; right valve hinge (seen only in a broken valve) 

 consists of a stirpate, projecting anterior tooth, deep anteromedian socket, locellate 

 posteromedian groove and posterior tooth (broken). 



Dimensions (mm). 



L H W 



Io. 4338 Carapace male (holotype) 0-78 0-44 0-44 



Io. 4285 Carapace female o-8i 0-46 0-49 



Comparison. This species shows some resemblance to Hermanites cracens sp. nov. 

 but is smaller, has a more curved ventral ridge culminating in a short vertical ridge 

 in the posterior third and lacks the three small, curved longitudinal ridges behind the 

 subcentral-tubercle. 



Remarks. Hermanites scopus rarely occurs in the Lower and Upper Chocolate 

 Clays of the Rakhi Nala and Zao River sections and can easily be recognized by its 

 characteristic ventral ridge. 



