1502 THE VOYAGE OF H.M.S. CHALLENGER. 



Second Perseopods in close agreement with the first, the fifth joint perhaps a little 

 longer than the fourth. The branchial vesicles are more bowed out at the centre behind. 



Third Perseopods. — Side-plates broader than in the preceding pairs, without bristles, 

 the hind part deeper than the front. The branchial vesicles similar to the preceding pair. 

 The first joint very little longer but much broader than in the preceding limbs, the neck 

 narrow, the remainder of the joint oval, with about eight bristles round the front margin 

 and two or three near the top of the hinder ; the remaining joints as in the preceding 

 pair, but more elongate, bent back upon the first joint, and the two terminal joints folding 

 against the front of the fourth joint ; the third joint appears to be without spines on the 

 front margin. 



Fourth Perseopods. — Side-plates scarcely so large as the preceding ; the branchial 

 vesicles more dilated behind near the centre. First joint of long irregular pear-shape, 

 much longer than all the remaining joints together, or than the first joint of the 

 other pairs, broadest near the base, the hinder and rounded distal margin fringed with 

 bristles not closely set, the hind margin on the inner surface but not on the outer 

 emarginate for the reception of the short second joint ; the third joint longer than the 

 fourth, its front margin pectinate and carrying two bristles, apically a very little pro- 

 duced ; the fourth joint similarly armed, but with three bristles ; in each of these joints 

 the pectination near the apex is retroverted ; fifth joint scarcely so long as the fourth 

 and much narrower, the front margin finely pectinate; the finger small but more than 

 half the length of the fifth joint, slightly curved, tapering, pectinate on the inner margin. 

 The third joint is capable of reaching beyond the apex of the first. 



Fifth Perseopods. — Side-plates very distinct, broader than deep, the upper and lower 

 margins parallel, the rounded hinder angle having one bristle. The first joint a little 

 bent, rather wider above than below ; the second joint nearly as broad as the extremity 

 of the first, not longer than broad, the third joint broader than the fourth but not so long ; 

 the fourth joint with one bristle standing out stiffly near the apex of the straight front 

 margin ; the fifth joint scarcely so long as the third, bent at an angle to the fifth, but 

 otherwise straight ; on the inner side near the apex there is a stout little spine ; the 

 finger quite minute, the narrowed apical part bent up so as to convert the finger into a 

 little sturdy hook. 



Pleopods. — Coupling spines minute, with apical teeth ; the cleft spine having 

 the serrate arm shorter than that with the subapical dilatation, the first joint of the 

 inner ramus having only one seta below the cleft spine ; the rami with six joints apiece. 



Uropods. — Peduncles of the first pair longer than those of the second, in both pairs 

 shorter than the rami ; the rami have pectinate edges, those of the second pair being 

 apparently rather larger than those of the first ; in each case the inner ramus is the 

 longer ; this applies also to the third pair, in which the peduncles are very short, the 

 outer ramus reaching a little and the inner considerably beyond the telson. 



