62 BULLETIN OF THE 



appendages do not differ very much from those of P. carinatus figured on 

 Plates X. and XI. : the first maxillae and second maxillipeds are almosit exactly 

 as in P. carinatus; the distal segment of the mandibular palpus is broader and 

 more obtuse at the tip, but in other respects the mandibles do not differ ; the 

 second maxillae dift'er only in having the posterior division of the distal lobe of 

 the protognath proportionally a little smaller ; the first maxillipeds are similar 

 to those of P. carinatus, but the lamellar portion of the exopod is a little 

 hroader and more abruptly narrowed into a more slender flagelliform portion ; 

 the external maxillipeds are more slender than in P. carinatus, and the two 

 distal segments are subequal in length. 



The legs of the first pair reach to the tips of the external maxillipeds and are 

 as in P. teniiipes. The second (chelate) legs are very nearly alike, but the left 

 is a little longer than the right and reaches to about the tip of the antennal 

 scale ; both are about equally slender ; the carpi are more than a third of the 

 entire length, segmented throughout but more conspicuously distally, and com- 

 posed of about twenty segments, of which the most distal one is considerably 

 longer than broad, but all the others shorter than this and approximately equal 

 in length ; the chelae are alike, scarcely stouter than the carpus and only a little 

 more than twice as long as its distal segment. The third, fourth, and filth pairs 

 of legs are nearly as in P. tenuipes: those of the posterior pair reach consider- 

 ably by the tip of the rostrum, and the fourth and third are successively a little 

 longer ; the meri are sparsely armed with small spines, but the distal segments 

 unarmed excepting a few setae or hairs ; the dactylus in the third pair is about 

 a third as long as the propodus, and in the fourth pair about a fourth as long 

 as the propodus. 



The abdomen is rounded above, but is rather strongly geniculated and 

 slightly compressed at the third somite. The sixth somite is more than twice 

 as long as the fifth, longer even than the antennal scale or rostrum, and strongly 

 compressed. 



The telson is much shorter than the sixth somite, slender, and terminates, as 

 in P. tenuipes, in a triangular tip armed each side with two long and slender 

 spines of which the proximal is much the longer. 



The surface of the carapax and abdomen is minutely roughened, as in 

 P. tenuipes, by thickly crowded irregular transverse punctate ridges. 



The branchial formula is apparently just as in P. tenuipes, P. Montagui, etc., 

 and as in the following species, P. carinatus. 



MEASUREMENTS. 



Station 321 



Rex 9 



Length from tip of rostrum to tip of telson ..... 42.0 mm. 



" of carapax including rostrum 14.2 



" of rostrum .......... 6.3 



Breadth of carapax ......... 4.9 



Lene;th of antennal scale ......•• 5.6 



