FROM WEST PAKISTAN 



25 



margin anteromedially concave but is convex in lateral outline due to the ventral 

 inflation ; anterior margin broadly rounded, posterior with a short caudal process. 

 Anterior and posterior cardinal angles well-developed particularly in the left valve. 

 Left valve slightly over-reaches the right at the anterodorsal and posterodorsal 

 corners. Subcentral-tubercle present but not distinct. Eye-tubercle rounded, shiny 

 and distinct and lies below and slightly anterior to cardinal angle. Surface ornamen- 

 tation consists of reticulations and longitudinal ribs. There is a variation in the 

 strength of the longitudinal ribs, those on the ventral surface are stronger and curved 

 convexly downwards in the middle. Marginal rim narrow and low. Anterior and 

 posterior margins denticulate. Valves deep in internal view. Normal pore canals 

 fairly numerous and perhaps each reticule has one normal pore canal. Radial pore 

 canals simple, straight, sparse, irregularly spaced, few crossing one another, approxi- 

 mately 20 anteriorly and 8 posteriorly. Line of concrescence and inner margin 

 coincide — no vestibule. Duplicative fairly wide — 0-073 mm. anteriorly, 0-055 mm - on 

 the posterior extremity. Selvage distinct and subperipheral ; situated in the right 

 valve on the outer sixth of the anterior margin. Right valve with a ventral flange 

 groove between selvage and flange. Muscle scar pattern with four adductor scars in 

 an almost vertical superposition at the posterior margin of the muscle scar pit and 

 two more or less rounded frontal scars. Hinge holamphidont with the following 

 details of the hinge elements : 



Element 

 Anterior 



Anteromedian 



Posteromedian 



Posterior 



Dimensions (mm). 



Left valve 



Deep socket bounded 

 on all sides, eye- 

 socket lies almost in 

 the middle of it. 

 Conical tooth, 

 projecting slightly 

 towards anterior. 

 Denticulate bar 



Deep and elongate 

 socket unbounded on 

 ventral side. 



Right valve 

 Strongly projecting 

 stirpate tooth. 



Deep socket narrowing 



posteriorly into a long 



groove. 



Locellate groove, the 



anterior part deeper than 



posterior. 



Large bilobate tooth, the 



anterior lobe lower than 



the posterior. 



Io. 4319 Carapace male (holotype) 



Io. 4272 Carapace female 



Io. 3102 Left valve male 



Io. 3103 Right valve male 



Comparison. This species has already been compared with " Anommatocythere 

 laqueata sp. nov. 



L 



H 



w 



o-66 



o-39 



o-39 



0-63 



0-42 



0-44 



0-64 



o-39 



— 



0-63 



o-37 



— 



Remarks. The vertical range of the present species in the Rakhi Nala and Zao 



