15 



The Indian form agrees with Kishinouye's figures of P. cmialiculakis and 

 ■with Spence Bate's of P. canaliculatus var. japonicus. As Stimpson and others 

 have remarked, DeHaan's description certainly does not apply to this species. 



The largest of our Indian specimens is 7 inches long. 



The rostrum, which is slightly double-curved, reaches just beyond the 

 tip of the antennular peduncle : dorsally it has 9-11 teeth, ventrally 1. 

 The groove on either side of the rostral crest is co-extensive with the post-rostral 

 crest (which is itself canaliculate) to within half-an-eye-length of the posterior 

 border of the carapace. 



There is a small post-ocular spine, continued as a short ridge running 

 parallel with the rostral crest ; posteriorly this ridge is recurved on itself to form 

 a narrow loop. The post-antennular ("antennal") spine is very strong and, 

 as in other species, is continued obliquely backwards as a sharp ridge to the 

 base of the hepatic spine. The oblique post-orbital crest is longer and more 

 oblique than in any of the preceding species. As usual, the cervical groove is 

 present only in the vicinity of the hepatic spine. The subhepatic crest and 

 groove, defining the anterior limit of the branchial region, are very distinct, and 

 take a somewhat sinuous course from a point near the antero-lateral angle of 

 the carapace to a point lying vertically below the posterior limit of the cervical 

 groove. 



The antennular scale does not itself reach beyond the eyes, though its setae 

 do. The antennular flagella are less than half the length of their peduncle. 



The external maxillipeds and 3rd chelipeds reach to about the middle of 

 the antennal scale. In males which appear to be adult the dactylus of the ex- 

 ternal maxillipeds is hardly half as long as its propodite and articulates almost 

 end-on with it. There is no distinct spine on the ischium of the 1st chelipeds, 

 but the spine on the basis of this and of the next appendage is very strong. 

 The last pair of thoracic legs, as in all Indian species except semisulcatus, have 

 an exopodite. 



On either lateral border of the telson, in its distal half, are three spinules. 



The andricum is structurally like that of P. monodon, except that the distal 

 end of the anterior (apposed) border of each lobe is prolonged to form a fleshy 

 lobule of some size. The " thelycum " has the form of a pocket (open anterior- 

 ly) owing to the fusion of its lobes. 



There are 9 specimens in the Indian Museum, registered as follows : — 



— = — : „ Hooglily Delta. Bengal Pilot Service. 



2764 



— = — Andamans. G. H. Booley. 



3923 



— Q— Orissa Coast. Investigator." 



