62 THE VOYAGE OF H.M.S. CHALLENGER. 



The three posterior segments of the thorax are closely appressed together and 

 separated by a considerable interval from the anterior region of the thorax. These 

 segments, together with the abdominal shield, form a pear-shaped region, the apex 

 being directed backwards ; these segments, moreover, are convex above, and of equal 

 antero-posterior diameter. They have indications of a pair of dorsal spines, which arc 

 well developed in Eurycope fragills; their antero-lateral margins are directed forwards 

 as shown in the figure which illustrates this species (PI. IX. fig. 1). 



The abdominal shield is roughly triangular in form ; between its concave anterior 

 border and the concave posterior border of the segment in front is an area traversed 

 by one or two longitudinal furrows ; this probably corresponds to the fused terga of the 

 two or three anterior segments of the abdomen. 



The abdominal shield terminates posteriorly in an obtusely pointed extremity ; 

 anteriorly to this on each side is a short lateral process, situated just above the articula- 

 tion of the uropoda ; the antero-lateral margins of the abdominal shield are slightly 

 prolonged into processes which correspond with those upon the segments in front. 



The dorsal surface is convex and divided by two shallow longitudinal furrows into 

 three areas, one median and two lateral. 



The antennules are of considerable length and consist of five joints and a terminal 

 flagellum. The first joint is much the largest, and, as is usual, is prolonged into a flat 

 process beyond the articulation of the second joint ; the second joint is considerably 

 more slender and shorter than the first joint ; the third joint is of nearly equal length 

 with the second, but much narrower ; the fourth joint is extremely short, the fifth is as 

 long as the third ; the flagellum consists of a very large number of joints, which become 

 longer as well as more slender towards its tip. 



The antennse are rather more than twice the length of the body, the proximal joints 

 are very short, the two distal joints are of extreme length and subequal. 



The mandibles (PI. IX. figs. 3, 4) closely resemble those of Eurycope sarsii ; the palp 

 is long and three-jointed ; the terminal joint is curved in the form of a claw ; the 

 cutting edge of the mandible is furnished with five or six tooth-like processes of unequal 

 size among which are a few scattered hairs, below is a thick tuft of slender hairs; the 

 molar process is stout with a blunt edge. 



In the first pair of maxillae the inner blade is very slender, with a lew slender hairs 

 at its apex and no stout spines like those at the outer blade. 



The maxillipedes appear to resemble entirely those of Eurycope sarsii (see PI. XL fig. 7). 



The thoracic appendages, as in all the other species of this genus, are specialised into 

 two series, the four anterior pairs being ambulatory, the three posterior natatory. 



The four anterior pairs gradually increase in length from before backwards, the first 

 being the shortest and the fourth the longest. The measurements in an example chosen 

 at random are as follows : — 



