854 THE VOYAGE OF H.M.S. CHALLENGEE. 



Fifth Perwopods. — The side-plates shallow, not narrowed behiud, serrate and fringed 

 round the lower and hind margins. Branchial vesicles small, apparently with a small 

 accessory lobe at the base as in the other pairs. First joint much longer and broader 

 than in the preceding pairs, about once and a half as long and more than once and a half 

 as broad, with short sjjines along most of the very convex front rim, setae along the 

 shorter, also convex hind rim ; the second joint short, all the others elongate, of nearly 

 equal length, none so long as the first joint, all bordered with spines of various lengths 

 and thicknesses, some of which are prickly, many with short bent tips and a small 

 accessory thread, those on the slightly serrate margins of the finger being slender, prickly, 

 not decreasing in length as they approach the tip of the finger, the tip itself broken. 

 This limb, though very much longer than the fourth pereeopod, cannot be considered 

 nearly double as long. 



Pleopods. — The coupling spines on the third pair being seen full face showed two 

 lateral retroverted hooks on each side, one of them having a third on one of its sides and 

 an appearance near the base of two little upturned points ; those on the first pair, less 

 well placed for observation, appeared to have more hooks, and more on one side than the 

 other ; the cleft spines showed a row of five on the first pleopods, of four on each of the 

 following pairs ; the interior roughening of the longer arm was in this species very 

 consjjicuous. The joints of the rami numbered from fifteen or sixteen to eighteen. On 

 the peduncles there were plumose setse and some spines. 



Uropods. — Peduncles of the first pair considerably longer than the rami ; the rami 

 acute, with small spines on the upper margins, not extending to the apex, one ramus 

 longer than the other ; peduncles of the second pair longer than the inner ramus ; the 

 outer ramus broken, the inner reaching back between the longer and the shorter ramus 

 of the first pair ; the third uropods broken off. 



Telson short, not reaching far beyond the produced sides of the sixth pleon-segment, 

 rather longer than broad, the broad distal margin with a slight tendency to crenulation, 

 set about with plumose cilia and having a small spine on either side of the almost angled 

 centre. 



Length. — The specimen figured life-size on PI. LXIII. fig. a., measured three-fifths of 

 an inch, exclusive of the antennae. 



Locality.— ^taiiou. 317, near the Falkland Islands, February 8, 1876; lat. 48° 37' 

 S., long. 55° 17' W.; depth, 1035 fathoms; bottom, hard ground (gravel); bottom 

 temperature, 35°"7. Two specimens. The more complete specimen was mounted on 

 board the vessel, and labelled as obtained " from net at the weight." 



Remark. — The specific name refers to the glassy slipper-like cap over the nail in the 

 peraeopods which is found in this species, and indeed in many others of the same family. 



