REPORT ON THE CRUSTACEA MACRURA. 503 



Tribe Polycarpidea. 



This tribe consists of all those normal Phyllobranchiata in which the second pair of 

 pereiopoda is slender, and in which the carpos is divided into a greater or less number of 

 articuli. It includes the families Nikida?, Alpheidse, Hippolytidae and Pandalidse. 



Family Nikid^;. 



This family consists of those genera which have the carapace produced anteriorly to a 

 rostrum that is horizontal with the dorsal surface, the mandibles without a psalistoma 

 or synaphipod, the first pair of pereiopoda simple or chelate and stronger than the 

 second pair, which is minutely chelate and has the carpos multiarticulate. 



It corresponds nearly with the Lysmatinse of Dana and Kingsley, but I prefer to 

 consider the genus Nika, which Dana places first in his list, as being the type of -the 

 family, inasmuch as it exhibits the point of union between the two forms, or those genera 

 which have the first pair of pereiopoda on one side simple and on the other chelate. In 

 GlypTiocrangon we find that both hands of the first pair are simple, with a flexible 

 dactylos, after the manner of the one on the left side in Nika, and in Lysmata both are 

 chelate as on the right side in Nika. 



Glyphocrangon, A. Mdne-Edwards. 



Glyphocrangcm, A. Milne-Edwards, Ann. d. Sei. Nat., ser. 6, torn. xi. p. 3, 1884. 

 „ Sidney Smith, Rep. "Albatross" Dredgings, 1886. 



The external tissue of the species that belong to this genus is hard and rigid, and 

 exhibits a tendency to tuberculose ornamentation ; the carapace is subcylindrical, scarcely 

 a third the length of the animal, measured from the frontal margin to the extremity of 

 the telson. Anteriorly it is produced to a strong, rigid, and sharp pointed rostrum, 

 dorsally depressed in the median line. The frontal margin has the orbit broadly but not 

 deeply excavate, and armed on the outer canthus with a large spine-like tooth. There is 

 another of similar character corresponding with the second pair of antennae, and 

 posteriorly to this, but at a slightly higher level, is another tooth that varies in different 

 species and corresponds with a longitudinal ridge. There are eleven longitudinal 

 ridges, one median and five on each side of it, and these ridges are more or less pro- 

 nounced in the several species, being most distinct in the less tuberculose forms. The 

 median ridge exists only on the rostrum and frontal region as a minute line of elevation, 

 terminating in a transverse groove that separates the frontal from the gastric regions ; 

 one on each side of the median, commencing at this groove, traverses the carapace to the 

 posterior margin ; on the outer side is another ridge, more conspicuous behind the 



