116 MESSES. NOEMAN AND STEBBING ON THE 



Genus 2, Strongylura, G. O. Sars. 



Animal elongated, subcylindrical, slightly narrower in the middle ; integument very 

 hard. Cephalic segment moderately large, attenuated in front, without distinct ocular 

 lobes. Pleon larger than usual, perfectly cylindrical, smooth, composed of six evenly 

 arched segments, the last cupuliform. No eyes. 



Upper antennae in female 4-jointed. Lower antennae much more slender, distinctly 

 6-jointed, and having a rudimentary flagellum ("flagello rudimentario excepto, distincte 

 6-articulatae ") . 



Mandibles well developed, with the edge curved inwards and sparingly denticulated : 

 molar process moderately large, laminar, finely crenulated apically. 



Gnathopods strong, formed as usual. 



Ambulatory feet slender and long, the fingers narrow ; hinder pairs slightly different, 

 more spined, and with the basal joint much constricted in its upper part. 



Pleopods entirely absent in the female. 



Uropods very short, biramous ; external branch very minute, tuberculiform. 



The above characters constitute the definition of the genus as given by its author. 



Strongylura arctophylax, n. sp. (Plate XXIV. fig. in.) 



This is a neat compact little species with shining hard integument. The carapace 

 is comparatively short (in. d), the anterior margin forms an obtuse angle. The first 

 free peraeon-segment is as wide as the carapace at its widest part ; the succeeding five 

 segments gradually diminish in width backwards, the last being of the same width as 

 the first five pleon-segments. These are short, close-set, and with their edges folded 

 under the animal, so as to be visible ventrally (in. pi.), where there is no sign of any 

 pleopods. The sixth segment of the pleon is as long as three of those that precede it, 

 and as broad or even a little broader in the anterior portion ; but the latter half narrows 

 rapidly to the rounded termination. The uropods are set on well underneath on each 

 side of the almost circular anal opening. 



The upper antennae (in. a.s) have the large first joint of no very great length, 

 considerably wider at the base than distally ; the second joint is not half the length of 

 the first, and increases in width distally ; the third is half the length of the second and 

 narrower ; the flagellum appears to be a single conical piece, equalling in length the 

 two preceding joints ot trie peduncle, and ending in two long setae. 



The lower antennae (in. a.i) are, as usual, much more slender than the upper, but 

 their length is not greatly inferior ; the last joint of the peduncle is longer than its two 

 predecessors combined (the latter being short) ; it is thin and much curved ; from it 

 springs the uniarticulate flagellum, terminating in one long and two short setae; in 

 other respects resembling that of the upper antennae, but being of much smaller size. 



