112 CRUSTACEA MALACOSTRACA. II. 



Chelipeds (fig. ah) moderately strong, somewhat long. The coxal joint is distinctly marked 

 off; the basal joint is very thick, only a little shorter than the carpus, which is a little less than 

 twice as long as deep. Chela considerably longer than the carpus, inconsiderably more than twice as 

 long as broad (fig. 2i); movable finger almost as long as the anterior margin of the hand and distally 

 much curved, and the major middle portion of its incisive margin is irregular with several moder- 

 ately small or very small teeth and two minute spines; the fixed finger has nearly the proximal half 

 of its incisive margin finely serrate, while the distal half has the two protuberances found in the 

 immature male, but both are lower and the distal protuberance without marginal incisions and teeth 

 excepting a single small, acute tooth at its end and just at the origin of the terminal, oblong-triang- 

 ular, acute part of the finger. 



Thoracic legs long and slender (fig. 2 h), subsimilar in all particulars excepting that the spines 

 on the anterior pairs are very short, on the posterior pairs somewhat more developed; sixth joint is 

 very long and considerably longer than seventh with claw. 



Abdomen (fig. 2 k) somewhat longer and, as usually, conspicuously thicker than the thoracic 

 segments. Five anterior segments with ventral tubercles; the tubercle on third segment triangular 

 but almost twice as broad as high; from that segment the protuberances decrease in size both forwards 

 and backwards and all are somewhat or fully rounded. Pleopods strong with very long setse. -- Sixth 

 segment strongly produced backwards in a somewhat slender process with the upper margin distinctly 

 concave; the result is that the uropods originate considerably before the middle of the segment and 

 terminate before its end. - - Uropods (fig. 2k) with the peduncle about as long as deep; endopod three- 

 jointed, with first joint thicker and much shorter than the second, which is a little shorter than the 

 third; exopod very slender and as long as the sum of two proximal joints of the endopod, two-jointed, 

 the first joint very short, the second long. 



Length 3.8 mm . 



Remarks. C. arctophylax is allied to C.Voringii, but the female and the subadult male of the 

 two species differ sharply in the ventral abdominal processes, the third process being much longer 

 than the others in C. arctophylax, while in C. Voringii the second process is the longest; furthermore 

 the female of C. Veringii has small pleopods without setae, while in the female C. arctophylax pleopods 

 seem to be wanting; a third character- is the difference in the above-described distal tubercle on the 

 incisive margin of the fixed finger of the chelae. -- According to the figures of the male of C.Voringii 

 published by Sars this animal seems to differ sharply from the male of C. arctophylax by having the 

 first joint of both endopod and exopod of the uropods much longer in proportion to the second joint than 

 in the last-named species, and in C. Voringii the terminal joint of the antennulse is only somewhat longer 

 than sixth joint, while in C. arctophylax the seventh joint is more than twice as long as the sixth. 



C. arctophylax was established by Norman & Stebbing on a single female specimen; they 

 referred, however, the species wrongly to the genus Strongylura, but it must be emphasized that their 

 work was written before any figure of Cryptocopc Voringii G. O. S. or Strongylura cylindrata G. O. S. 

 had been published. Stebbing's figures of the animal from above, of the cheliped, thoracic legs, etc., 

 leave no doubt that the animal is either C. Voringii or C. arctophylax as defined here ; the locality for 

 the specimen and the ventral abdominal process shown on his fig. Ill PI. but not mentioned in the 



