•Zi 



already mentioned, P. koolooense seems to be the Western Himalayan, P. 

 atkinsoniammi the Eastern Himalayan form. 



Carapace : length in adult barely three-fom-ths its greatest breadth, depth a 

 little over two-fifths its length, quite flat behind the frontal slope. The gastric 

 region is extremely well defined, but its only indications of areolae are anteriorly, 

 where the front limits of the mesogastric and epigastric subregions are well 

 graven. The gastric region is festooned, outside the cervical groove, by six very 

 distinct areolae, two of which, on either side, belong to the epibranchial regions, 

 and two (smaller) in the middle to the anterior cardiac region ; the epibranchial 

 regions are further subdivided by a broad obliquely transverse groove. The 

 cervical groove is very deeply graven, and cuts the post-orbital crests at a point 

 in hne with the inner angle of the external orbital spine. The frontal region is 

 tuberculous ; the anterior part of the gastric region is rugulose ; the anterior 

 part of the epibranchial regions is obliquely rugose ; the side-walls of the 

 carapace are tuberculous anteriorly (as are the well-defined suborbital lobes), 

 and are obliquely rippled posteriorly, fine ripplings extending well over the 

 postero-lateral borders. 



The epigastric crests, though separated from the rather oblique post-orbital 

 crests on either side by a groove, do not at all overlap the post-orbital crests, 

 but merely form the most convex part of one common curve with them, this 

 being the chief character besides size that separates this species from P. 

 koolooense ; the edge of these crests is rugulose and crenulate. 



Front moderately decHvous, faintly and broadly bilobed in a dorsal view, 

 its breadth in the adult considerably less than one-third the greatest breadth of 

 the carapace, its edge (like that of the orbit) well defined and very distinctly 

 crenulate or beaded. Upper edge of orbit markedly sinuous. External orlMtal 

 tooth prominent, subacute, and separated from the lower border of the orbit hy 

 a bight. 



Antero-lateral borders of the carapace hardly as long as the postero-lateral 

 borders, raised, serrulate, very gently curved, the curve not running on to the 

 dorsum of the carapace posteriorly ; the epibranchial tooth is not pre-eminent 

 above the general serration of these borders. 



In the adult male abdomen the length of the 6th segment is nearer two- 

 thirds than one-half its greatest breadth, and that of the 7th segment is quite 

 equal to its greatest breadth. 



Antennular fossae very narrow : interantennular septum very broad, formed 

 rather more by the inturned callosity of the front than by the epistome. 



First (true 2nd) antennal joint nearly square, the two succeeding joints 

 covered by and in contact with the front. 



Mandibles and maxillipeds as in P, fluviatile var. ibericum, the merus of 

 the external maxiUipeds being broader than long : the only diff'erence is that 

 the antero-external anole of this merus is not so evenlv rounded off. 



