442 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM:. 



indistinct articulations, while the four or five distal ones are separated 

 by conspicuous articulations, of which the ultimate is about twice as 

 long as broad, but the next three or four, each, only about half as long 

 as broad. The chela is slender, only a very little stouter than the distal 

 end of the carpus, nearly a third as long as the carpus, and about half 

 as long as the merus, and the digits are alike, about as long as the basal 

 portion, slightly gaping, and with a very few long, setiform hairs. The 

 third, fourth, and fifth pairs of legs are exceedingly slender, sparsely 

 armed with minute spinules and slender setaj ; and the dactyli are very 

 long and slender, slightly and regularly bent, and flattened a little verti- 

 cally (or in the direction of the plane of the cervature), and wholly un- 

 armed ; the fifth pair reach beyond the tip of the rostrum, and the fourth 

 and third pairs are successively a little longer; the dactylus in the fifth 

 l^air is a third or a little more than a third as long as the propodus, in 

 the fourth pair a little longer than in the fifth, and in the third pair not 

 far from half as long as the i:)ropodus. 



The abdomen is evenly rounded and not at all compressed above, and 

 less geniculated at the third segment than in P. 2Ionta(jui. The sixth 

 segment is about once and two-thirds as long as the fifth. The telson is 

 about once and a half as long as the sixth segment, and terminates in an 

 acutely triangular tip, armed each side with two long spines, of which 

 the proximal is very much the longer, and at the extreme tip with a few 

 long, plumose setsB. 



Measurements. 



