1260 THE VOYAGE OF H.M.S. CHALLENGER. 



third segment, is evanescent ; these two segments have also one or two lateral teeth or 

 tubercles behind the place of attachment of the branchial vesicles ; the fifth segment 

 is longer than the fourth, with some very inconspicuous raised points on the back ; the 

 sixth and seventh segments are subequal, about as broad as long, together shorter 

 than any one of the preceding segments, inconspicuously tubercled on the back. 



Eyes small, round, situated on the advanced lateral lobes of the head. 

 Upper Antennae in the largest specimen about seven-tenths of an inch in length : the 

 first joint of the peduncle thicker than the second, more than half its length ; the second 

 joint with the distal part rather abruptly thicker than the proximal ; the third joint 

 thinner than the second, in the longest specimen subequal to it in length, in others 

 intermediate in length between that and the first, widened at the distal end ; there are 

 setules and cilia scattered over the whole peduncle ; the flagellum a little shorter or a 

 little longer than the third joint of the peduncle, with twelve joints in a dissected 

 specimen, of which the first was the stoutest, nearly equal in length to the remaining 

 eleven together ; of these the first nine are widened distally, each carrying an apical 

 filament and setules, the serrate lower margin of the first joint being similarly furnished 

 at nine points. 



Lower Antennae not reaching the end of the second joint of the peduncle of the upper 

 antennae ; in structure as in the female. 



Mouth Organs as in the female. 



First Gnaihopods as in the female. 



Second Gnaihopods attached almost at the distal end of the narrow second segment, 

 which is there a little widened ; the first joint of great length, sometimes longer than the 

 segment as well as longer than the hand, though these proportions, like others, vary in 

 different specimens ; there is a little widening of the joint at the distal end, and as in 

 the female a small apical prolongation of the front margin ; the second joint is not 

 broader than long ; the third joint is a little longer than the second, with scarcely any 

 free front margin, the hind margin almost semicircular, with a setule here and there ; 

 the very small wrist is scarcely distinct from the very narrow base of the hand ; the hand 

 very long, nowhere very broad, widening gradually for about half its length, that is, 

 from the base to the beginning of the palm, which is defined by a small projecting tooth 

 carrying a palmar spine and setules ; thence the palm margin, fringed with a spine or 

 two and some spinules and setules, but otherwise smooth, runs a little obliquely so as to 

 narrow the hand till it projects in a prominent narrow tooth, followed by a small cavity 

 beyond which a broad tooth or process leads up to the hinge of the finger ; the finger is 

 greatly curved, of a length to match the palm, broad, especially where the inner margin 

 swells out with a prominence that bites against the large tooth-process of the palm. 



The Branchial Vesicles of the third and fourth segments are very long and narrow, 

 subequal in length to their respective segments. 



