73 



and sinuous, and gradually become indistinct beyond the point where the 

 cervical groove approaches them. 



Abdomen of adult male a broad-based triangle in outline ; 6th segment 

 with concave sides; its length exceeds its distal and equals its proximal 

 breadth ; 7th segment longer than broad, broadly rounded anteriorly. 



Mandibular palp as described in the diagnosis of the genus. 



Exopodites of all the maxillipeds with a strong, plumose flagellum. In 

 the external maxillipeds the exopodite is longer than the ischium ; the ischium 

 is longitudinally grooved near the inner edge ; and the merus is a lot broader 

 than long, and has an oblique anterior edge. 



Chelipeds very unequal in both sexes, longer in the male than in the 

 female ; their surface, to the naked eye, is smooth, sometimes almost polished. 

 The spine near the end of the upper border of the merus is distinct and usually 

 acute ; that at the inner angle of the carpus is strong ; the fingers are moder- 

 ately broad, they are strong and sharp pointed, and their tips are inclined to 

 cross; the dactylus is longer than the palm. In the smaller cheliped the 

 fingers are not much bent, and so do not gape much when closed ; one tooth 

 in the fixed finger may be enlarged, but there is no very marked inequality in 

 the teeth of the dactylus. In the larger cheliped the dactylus (especially of the 

 male) is much bent, and there is a large molar near its base and usually a 

 second enlarged tooth beyond its middle ; while in the fixed finger there is a 

 very much enlarged molar or double tooth not far from the base. 



Legs stout, not as long as the chelipeds in either sex ; dactyli strong, 

 longer than the propodites ; the longer projaodites are about thrice as long as 

 broad. 



In a large male the carapace is 1| inch long, 2tW inches broad, and 1 inch 

 deep, and the larger hand (fingers included) is 2| inches long, the extreme 

 length of the dactylus being 2 inches. In a large female the carapace is If 

 inch long, 2| inches broad, and 1 inch deep, and the larger hand is U inch long, 

 the extreme length of the dactylus being 1| inch. 



Outside the limits of the subgenus the nearest relatives of this species 

 seem to be P. liydrodromus and P. bouvieri. 



4016 



~V 



4035 

 ~4^' 

 4039 

 4 ■ 

 4116 



~F ■ 



3131 



3172 

 ~5~* 



