30 



of the epibranchial border being more than that of utklnsoniamim but less than 

 that of emphyseteum. 



— Simla. ' No donor recorded. 1 S (younjj). 



o 



— —. Kumaoii. A. W. Lawder. 1 c? (young). 



8. POTAMON (PoTAMON) ATKINSONIANUM, var. AMIUVIUM. 



This puzzHng little form is in a way intermediate between P. koolooeiise 

 and typical P. atkinsonkmum. 



As in P. atMnsonianum, the cervical groove is deep-cut in its whole extent, 

 and the ejDigastric crests form the convexity of a regular curve common to 

 them and the post- orbital crests. 



But like P. koolooense it is small and not quite flat in the carapace. 



An egg-laden female has a carapace Hths of an inch long and lf"o inch 

 broad. The eggs, which are fairly numerous, are about 2-5 mm. in diameter. 



-j^- Dharaini)ur, Simla, 5000 feet. N. Annandale. 3 cj, 2 ?. 



9. PoTAMON (Potamon) bifarium, Alcock. (Fig. 3.) 



This species can be sufficiently characterised by comparison with 

 P. atkinsonianum, which it very closely resembles, differing only in the 

 following particulars : — 



(1) The carapace is distinctly convex fore and aft behind the frontal slope ; 



(2) The antero-lateral borders of the carapace encroach on the dorsum 

 of the carapace posteriorly ; 



(3) The epibranchial and cardiac areolae that festoon the gastric region 

 outside the cervical groove are not so well defined ; 



(4) The abdomen of the adult male is broader, the 6th segment varying 

 in length (in specimens of equal growth) from two-thirds to half the greatest 

 breadth, and the 7th segmenc being a good deal broader than long ; 



(5) The legs are slenderer ; in the 1st and 4th (last) the length of the 

 propodite is twice its breadth, in the 2nd and 3rd the length of the 

 propodite is two and a half times its breadth, or even a little more. 



Carapace : length in adult about three-fourths its greatest breadth, depth a 

 little less than half its length, its surface being slightly convex fore and aft behind 

 the frontal slope. The gastric region is well defined, the narrow anterior lobe 

 of the mesogastric area being very distinct, and the front limits of the epigastric 

 areolae being indicated. Branchial regions bisected by an obliquely transverse 

 groove and further subdivided by a less distinct groove running roughly 

 parallel with the cervical groove. Cardiac region ftiirly distinct, as are the 

 two small oval facets between it and the gastric region. Cervical groove well 

 cut, becoming broad anteriorly and rather indistinctly breaking the post-orbital 



