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



Third Perseopods. — Side- plates broader than in the preceding segment, produced 

 below in two rather long lobes, the lower ends of which are wide apart. The first joint 

 broader above than below, with spines at four points on the nearly straight front margin, 

 the hinder with only some minute spinules ; the lower part of the joint squared on the 

 outer side, while the inner surface is pear-shaped ; the rest of the limb resembles the pre- 

 ceding perseopod, but is a little larger, and the fourth joint has three groups of spines on the 

 front margin, that is, the margin corresponding to the hind margin in the preceding limb. 



Fourth Perseopods. — Side-plates with a long lobe decurrent behind. The branchial 

 vesicles with an accessory pouch at the upper part. The first joint similar to that of the 

 third perseopods, but considerably larger, especially in breadth ; the rest of the limb 

 similar to the preceding, but the third and fourth joints considerably longer, and each 

 with spines at a point in the hind margin ; the fifth joint also rather longer. 



Fifth Peneopods. — Side-plates small, not decurrent. The first joint longer and 

 broader than in the preceding perseopods, rather more pear-shaped, although distally 

 broad ; the rest of the limb similar to the preceding, but all the joints longer. 



Pleopods. — Coupling spines very small ; cleft spines five in the first and second pairs, 

 four in the third pair, the branches of the cleft short and equal ; the joints of the rami 

 number from eighteen to twenty-two. 



Uropods. — The peduncles of the first pair longer than the rami, reaching just beyond 

 those of the second pair, but not so far as those of the third, with three or four spinules 

 on the inner margin, the outer clear ; the rami slender, the outer shorter than the inner, 

 each tipped with a large nail-like spine, having a small one by its side, the inner ramus 

 also carrying four or five small spines on its margin ; the peduncles of the second pair 

 shorter than the inner ramus ; the outer ramus much shorter and narrower than the 

 inner, each tipped as in the first pair, the inner also having two spines on the outer and 

 five or six on the inner margin ; the inner reaches back about as far as the inner of the 

 first pair, the outer not so far as the outer of that pair ; peduncles of the third pair shorter 

 than the rami, which are broad, lanceolate, subequal, the outer rather the longer, both 

 reaching a little further back than those of the other pairs ; the inner ramus has its inner 

 margin fringed with thirteen spines with plumose setse of different lengths ; on the serrate 

 lower portion of the more convex outer margin there are six spines with setse ; the outer 

 ramus has six or seven spines on its inner margin, and two or three on the lower part, 

 besides spinules on the upper part, of the outer margin. 



Tdson reaching beyond the peduncles of the third uropods, elongate, with the lateral 

 margins very slightly sinuous, on the whole tapering to a narrow emarginate termination. 



Length. — The specimen, in the position figured, measured half an inch from the 

 rostrum to the apex of the dorsal process on the second pleon-segment. 



Locality.- — The single specimen was labelled as taken "from the kelp in Stanley 

 Harbour, Falklands, Jan. 1876." 



