46 



Mandibular palp normal. All the maxillipeds have a long flagellum to the 

 exopodites. In the external maxillipeds the merus has a well-defined apex, 

 and is as long as broad. 



Chelipeds miequal, of somewhat fine make, their sm-face very finely 

 rugulose. The merus has crenulate edges, and a tooth just inside the inner 

 lower border, towards the distal end, is much enlarged. The carpus has the 

 usual bicuspidate spine at its inner angle ; its upper surfiice is not sunken, nor 

 is its anterior liorder inflated. The fingers gape when closed. 



The legs are long — but not longer than the larger cheliped— and slender ; 

 in the 1st and 4th pair the length of the propodite is two and a half times, in 

 the 2nd and 3rd pair three and a half times its breadth. 



The only specimen is a female, whose carapace is ItV inch long, IH inch 

 broad, and yVths inch deep. 



^^. Burma. W. Theobald. 1 9 . 



Group V. : larnaudii and stoliczkanum group. 



In this group, which includes, among exotic species, P. larnaudii, P. 

 brevimarginahmi, and P. stoliczkanum, and, among species appertaining to 

 the British -Indian raj, P. manii, P. priiinosum, P. turgidulimanus, and P. 

 tJiagateme, the cervical groove does not distinctly cleave the post-orbital crests ; 

 but it either becomes indistinct before reaching the crests, or, if it be distinct, 

 it runs nearly up to the crests, and then may either run behind them almost up 

 to the lateral epibranchial tooth, or else is lost in the neighbouring rugae. 



The Indian species and those most nearly related to them may be 

 tabulated as follows, exotic species being included in square brackets : — 



I. The tubercles and wrinkles of the dorsum of the carapace are chiefly 

 confined to the antero-lateral part of the epibranchial re<yions : 



1 . Post-orbital crests broken hito tubercles at their outer end ; 



merus of external maxillipeds as long as broad . . ■ [P- larnaudii.'] 



2. The post-orbital crests are continued without break into the 

 lateral epibranchial teeth ; merus of external maxillipeds broader 



than long . . . . . . .p. manii. 



II. Anterior third or half of the carapace thickly tuberculous and rugose ; 

 merus of external maxillipeds broader than long : — 



1. A gap between the outer angle of the orbit and the lower border 

 of the orbit : — 



i. Cervical groove deep and distinct . . • [P- hrevimarainatum.] 



ii. Cervical groove very indistinct anteriorly . . .P. priiinosum. 



2. No gap below the outer angle of the orbit . . .P. turgidiilinuimis. 

 III. The surface of the carapace is almost free of tubercles and wrinkles; 



post-orbital crests contiimous with the lateral epibranchial teeth : — 



1 . Edge of front two-lobed ; no distinct break between the epi- 

 gastric and post-orbital crests . . . . ■ [P- moliczkanum.] 



2. Edge of front four-lobed ; a distinct break between the epi- 

 gastric and post-orbital crests . . . . .P. fha<'atense. 



