212 



are slender and biramous in the female, but are uniramous in the male, in which 

 sex also those of the 2nd somite are particularly long and strong and end in a 

 spathulate joint. 



The gills are 14 on either side, disposed as follows : — a pair of arthro- 

 branchs to each segment from the IXth (external maxillipeds) to the Xlllth, 

 and a pleurobranch on each segment from the Xlth to the XlVth. The gill- 

 elements are filaments arranged in double rows on either side of a shaft (quadri- 

 serial). 



The genus is represented in moderate depths in the Caribbean Sea, the 

 Andaman Sea, and the Sea of Banda. 



1. PylOCheles miersii, Alcock and Anderson. 



Pylocheles miersii, Alcock and Anderson, Ann. Mag. Nat. Hist., Jan. 1899, p. 14. 

 Illustrations of the Zoology op the Investigator, Crustacea, Plate XLIII. Fig. 4. 



Carapace cuboidal, its membranous lateral walls being vertical, its anterior 

 border faintly sinuous, its dorsum quite free of setae. 



The abdominal terga 2-5 are separated from their pleura by a groove, and 

 the pleura 2-4 each have a longitudinal crescentic groove. The 6th tergum is 

 much longer than any of the others. The posterior segment of the telson is 

 obscurely bilobed. There are seta? on the edges of the pleura and on the surface 

 and edges of the telson and caudal swimmerets, but not on any other part of the 

 abdomen. 



Ophthalmic scales extremely short : eyestalks half as long as the carapace, 

 a narrow strip along their sides is imperfectly calcified : eyes markedly reniform. 



The 2nd joint of the antennular peduncle is the longest and the 3rd the 

 shortest : the upper antennular flagellum is nearly two-thirds the length of the 

 carapace. 



The inner of the 2 acicles of the 2nd joint of the antennal peduncle reaches 

 more than halfway along the eyestalk, the outer is shorter, both are obscurely 

 serrated : the antennal flagellum is longer than the carapace. 



The external maxillipeds reach as far as the tip of the eyes. 



The great chelipeds, which are perfectly equal, are not quite two-thirds the 

 length of the body, nearly half their extent being contributed by the hand. 

 The merus and ischium are smooth, and their common inner surface is marked 

 by an elongate-oval ring of imperfectly calcified integument : the trigonal carpus 

 has its lower border very short, but its upper surface is three-fourths the length 

 of the palm, is finely rugose, and has its anterior edge produced to form a salient 

 bilobed and finely serrrated setose crest : the lower surface of the hand is convex 

 and smooth, but the upper surface is flat, closely pitted and thickly covered with 



