FROM WEST PAKISTAN 21 



Comparison. Alocopocythere radiata sp. nov. is similar and perhaps related but 

 lacks the posterior concentric ridges. Moreover, A. radiata has ventral inflation 

 culminating in a ventral ridge and the longitudinal ridges radiate from the posterior 

 of a subcentral-tubercle. 



The present species has already been compared with Alocopocythere transcendens 

 sp. nov. 



Remarks. This species may be divided into the following morphotypes, which 

 may represent the chronological subspecies of A. transversa. However, because of 

 the difficulty in separating these from one another and also owing to the fact that the 

 reticulate forms recur in the Upper Eocene succession of the Rakhi Nala and Zao 

 River sections, these are here considered as morphotypes. 



Morphotype A 

 (PI. 5, figs. 4, 5, 7-10 ; PL 6, figs. 1-4) 



This has a reticulate surface. The reticulae are usually without any super- 

 imposed papillae but in some specimens a few small papillae at the junction of 

 reticulae are present. The postero ventral margin in lateral outline is curved in the 

 male but straight in the female. 



Dimensions (mm). 



L 

 Io. 4266 Carapace male 0-76 



Io. 4316 Carapace female (holotype) 0-71 



Io. 3107 Right valve male 0-85 



Morphotype B 



This comprises the transitional forms which fall between Morphotype A and 

 Morphotype C. It has slightly papillose reticulae. Specimens Io. 5004-5 from 

 sample 24155. 



Morphotype C 

 (Plate 6, figs. 5-8 ; Plate 7, figs. 1-4 ; Plate 8, fig. 4) 



This is similar to Morphotype B, but has a combination of reticulations and 

 papillae and a curved postero ventral margin in both male and female. 



Dimensions (mm). 



L H W 



Io. 4267 Carapace male 0-78 0-46 0-44 



Io. 4268 Carapace female 0-76 0-46 0-44 



Io. 4269 Right valve male (broken) o-8o — — 



Morphotype D 



This includes the intermediate forms between Morphotype C and Morphotype E. 

 Specimens Io. 5006-7 from sample 24175. 



H 



w 



0-44 



o-45 

 0-46 



0-44 

 0-44 



