24 Major A. Alcock and Capt. A. R. S. Anderson on 



length of the fully extended body and nearly half as long 

 again as the legs ; the first two pair of legs are nearly of one 

 length, but the third pair are the longest by nearly a dactylus, 

 owing to the elongation of their propodite, which is nearly 

 five times as long as the dactylus. 



A female from off the Travancore coast, 420 fathoms, is 

 30 millim. in extreme length when fully extended, and has 

 chelipeds 86 millim. long and third pair of legs 55 millim. 

 long. 



Colour salmon-pink, eyes deeply pigmented. 



Ptychogaster investigatoris, sp. n. 



Carapace short, its length (including the rostrum, which is 

 slightly more than a fourth the total length of the carapace) 

 is only equal to that of the first five and a half fully extended 

 abdominal terga ; its surface is everywhere studded with 

 spinules and spines, the largest of which show a tolerably 

 plain arrangement in four longitudinal series. 



The only abdominal tergum (besides the telson) that is 

 quite free from spines is the third : the first tergum has a 

 transverse spiny carina continuous with a similar carina on 

 the edge of either pleura of the second segment ; the second 

 has a transverse raised row of four large spines, besides 

 several teeth ; both the fourth and fifth are separated from 

 their pleuise on either side by a longitudinal row of two or 

 three spines or serrations ; the sixth is covered with retrorse 

 spinules and spines, including three conspicuous transverse 

 series, of which the last far overhang the telson. 



The first segment of the telson is hardly perceptibly longer, 

 and slightly narrower, than the second ; the surface of both 

 bears some inconspicuous capillary spinelets or bristles. 



The pleuras of the third and fourth abdominal somites are 

 devoid of spines. 



The external maxillipeds are unarmed, except for the ischial 

 serrations, and are very hairy in their distal half. 



Chelipeds and legs long, slender, and spiny ; the chelipeds 

 in the female (male unknown) are about 2§ times the length 

 of the fully extended body and half as long again as the 

 legs ; the racquet-like form of the hand, due to the bowing 

 of the basal half of the fingers, is more than ordinarily con- 

 spicuous. 



Of the first three pair of legs the first is slightly the longest 

 and the second slightly the shortest ; the dactyli of all are 

 hardly more than a quarter the length of the propodites. 



A female from the Andaman Sea, 405 fathoms, is 



