25 



but the frontal region is tuberculous, the anterior limit of the gastric region is 

 rugulose, and the antero -lateral part of the epibranchial regions is obliquely 

 rugose ; the side-walls are obliquely rippled, the strise passing over the postero- 

 lateral borders, and the pterygostomian regions and well-defined suborbital 

 lolies are pimpled. The epigastric crests are rugulose ; though only just in 

 advance of the post-orbital crests, they usually slightly overlap the latter, and 

 do not usually form a simple curve with them ; the edge of the post- orbital 

 crests is crenulate. 



Front moderately declivous, very faintly bilobed even in a dorsal view, its 

 width less than one-third the greatest breadth of the carapace in the adult, its 

 edge well defined and beaded. External orbital tooth subacute, separated 

 from the lower border of the orbit by a notch. 



Antero-lateral borders of the carapace slightly shorter than the postero- 

 lateral, gently cm-ved (the curve invading the dorsum of the carapace 

 posteriorly), very well defined, regularly crenulate ; no large epibranchial tooth. 



Abdomen, antennules, antennae, and mouth-parts as described for P. 

 flmiatile var. iberkum, the merus of the external maxillipeds being broader 

 than long, and having its antero-external angle evenly rounded. 



The only points where the chehpeds and legs differ to any extent from 

 those of P. fluviatile var. iberkum, are that the •2nd (longest) pair of legs often 

 reach beyond the tip of the larger cheliped, and that the propodites of the legs 

 are shorter— their breadth, in the 2nd and 3rd pairs, being hardly half their 

 length— and have their anterior border very distinctly (longitudinally) grooved, 

 so as to present two very distinct edges, one serrated, the other smooth — as is 

 the case Avith most species except P. Jluvkitile. 



In a large female the carapace is 1^ inch long and nearly 1^ inch broad ; 

 in the largest male of the collection it is IfV by 1\% inch. 



This seems to be a very common species in the Western Himalayas, as P. 

 atkinsonianum is in the Eastern Himalayas. The two species are extremely 

 close to one another, but P. koolooense is smaller, has a carapace that is not so 

 flat nor so distinctly areolated, and almost always has the epigastric crests 

 distinctly, if shghtly, in advance of the post-orbital crests. 



6920 



3 ■ 

 6962 



3 ■ 



,, 4028 

 L.r -^. 



■1047 



4 

 7697-8 



7 

 7635-37 



D 



