26 RATHBUN 



line with the acicle. The branchiostegal sinus is rectangular, the angle 

 rounded. From the post-antennal spine a ridge runs nearly straight 

 back, with one interruption, almost to the posterior margin. A groove 

 runs from just in front of the middle of the posterior margin vertically 

 half way down the carapace. 



Eyes light brown, almost colorless in alcohol, nearly as wide as their 

 stalks. The antennular scale, which is foliaceous and has a sharp spine 

 at the upper extremity, is as long as the basal joint of the peduncle. 

 Antennal scale nearly half as long as carapace proper, elongate-oval, 

 with a stout midrib, and its outer border thickened and ending in a 

 slender terminal spine. 



The external maxillipeds, which are stouter than any of the last three 

 pairs of legs, reach almost to the tip of the antennal scale ; all their joints 

 are setose ; the antepenultimate segment is broadened in its middle por- 

 tion, tapering at each end. 



The first two pairs of legs are similar in form, the second pair the 

 longer and about half the length of the body. In the first pair, the pos- 

 terior border of the merus and palm are spinous, and the distal angles of 

 the wrist are produced ; the fingers equal the palm in length. In the 

 second pair, the posterior border of the basis, ischium, merus, and palm is 

 spinous ; the angles of the wrist are more strongly produced ; the fingers 

 are nearly as long as the palm. In each case the hand forms about 

 two fifths of the entire length. The filiform third pair (tip broken off) 

 are equal in length to the carapace exclusive of the rostrum. The fourth 

 and fifth pairs have the terminal joint narrow-oval ; the fifth pair are the 

 longer and two thirds the length of carapace. 



The first three abdominal somites are non-carinate, the fourth is pos- 

 teriorly produced in a thin compressed spine which is carinate and has a 

 slight notch at its base, visible in profile ; the sixth has a longitudinal 

 groove on either side. The telson is a little longer than the sixth somite, 

 shorter than the inner uropod, and much shorter than the outer one ; it 

 is truncate at the tip. 



Dimensions. In an egg-laden female the length of the carapace and 

 rostrum is 23.6 mm., the rostrum 1.8 mm., the abdomen 42 mm. 



Type locality. Off Cortez Bank, Calif., 984 fathoms (Albatross station 

 2919), one female. 



This species is akin to P. gilesii Wood-Mason, from the Indian Ocean, 

 which also has a serrated carina running the whole length of the cara- 

 pace, but the character of the rostrum alone separates it distinctly from 

 that species. In P. gilesii, the rostrum is a fine, acute, upcurved spine, 

 extending about a third of its length beyond the eyes. 



