FROM WEST PAKISTAN 



15 



reticulate. Antero-dorsal furrow deep, bounded anteriorly by a short almost 

 vertical ridge joining the eye-tubercle. Anterior marginal rim high, continuing as a 

 less high rim round the venter and posterior. Anterior margin ornamented with 

 8-10 short spines, posterior with a postero-ventral spine, although these are pre- 

 served in a few specimens only. Duplicature moderately wide, 0-073 mm. anteriorly 

 in right valve female. Selvage prominent in both valves, situated in the outer third 

 of the duplicature in right valve but sub-peripheral in left valve. Along the venter 

 it is markedly concave antero-medially. Right valve has well-developed ventral 

 and anterior flange grooves. Normal pore canals simple, small. Radial pore canals 

 more or less straight, simple, some in groups of two or three, frequently crossing each 

 other. There are approximately 35 radial pore canals in the anterior and 20 in the 

 posterior. Line of concrescence and inner margin coincide throughout. Muscle 

 scars consist of sub-vertical row of four adductors, situated on the posterior margin 

 of the muscle scar pit, with an oval frontal scar and two somewhat rounded mandi- 

 bular scars below. Hinge holamphidont with the following details : 



Element 

 Anterior 



Anteromedian 



Posteromedian 

 Posterior 



Left valve 



Deep socket confluent 

 with ocular sinus, 

 bounded on all sides. 

 Subcorneal tooth with 

 straight anterior and 

 convex posterior in 

 dorsal outline. 

 Denticulate bar 

 Deep slightly elongate 

 socket open on ventral 

 side. 



Right valve 

 Highly projecting 

 stirpate tooth, ocular 

 sinus lies below it. 

 Deep rounded socket 

 opening into postero- 

 median groove 



Locellate groove 

 Pessular tooth, high 

 on posterior tending 

 towards reniform. 





L 



H 



w 



Carapace male 



072 



o-43 



0-42 



Left valve female (holotype) 



0-63 



0-44 



— 



Right valve female 



0-64 



o-39 



— 



Left valve female 



o-59 



o-39 



— 



Right valve male 



0-63 



0-38 



— 



Dimensions (mm). 



Io. 3104 



lo. 4315 

 Io. 3105 

 Io. 4261 

 Io. 3106 



Comparison. Alocopocythere abstracta sp. nov. is a very closely related species, 

 but is more elongate, and has a straight rather than rounded posteroventral margin 

 and less deep reticulations. Alocopocythere transcendens is perhaps ancestral to 

 Alocopocythere transversa sp. nov. but is smaller, and lacks the posterior concentric 

 ridges and a short ridge in the anteroventral area. Alocopocythere fosstdaris (Lubi- 

 mova and Guha) (i960) from the Miocene of Kutch is a similar species but which 

 differs however, in the lateral outline of the carapace. 



Remarks. Specimens of A. fossularis (Lubimova and Guha) from the type 

 locality in Kutch were not available for comparison. 



