1028 THE VOYAGE OF H.M.S. CHALLENGER. 



deeply produced and pointed. Branchial vesicles oval, descending a little beyond the 

 hind lobe of the side-plate. First joint long and rather narrow, slightly wider above 

 than below ; the front margin nearly straight, with some small spines and setae, the 

 hind margin serrate, continued in a crenate lobe below, partially overlapping the short 

 second joint ; the third joint longer than the fourth, equal to the fifth, apically produced, 

 more behind than in front, slender spines at four points on each margin ; the fourth 

 joint also distally widened, a little produced behind, and there tipped with spines, of 

 which there are three groups on the front margin ; the fifth joint has spines at six 

 points in front, and at four or five behind, of these the apical group being large and 

 strong ; the finger as in the preceding peraeopods. 



Fourth PersBopods. — The side-plates with a minute front lobe, the hinder as in 

 the preceding segment. The limb broader and stronger than the preceding pair, the 

 first and second joints larger but otherwise similar, the third joint more pronounced at the 

 hinder apex, longer than the fifth joint ; the fourth joint not at all produced behind, 

 decidedly shorter than the fifth. 



Fifth Perseopods. — The side-plates deeper than broad, crenate below. The first joint 

 considerably larger than in the preceding pair, the hind margin more convex, all the 

 joints after the second longer, especially the fourth joint ; the fifth joint scarcely so 

 broad, rather more decidedly drawn down at the apex of the hind margin than in the two 

 preceding pairs. 



Pleopods. — Peduncles long in comparison with the rami ; coupling spines slender, 

 with an apical and a lateral retroverted tooth, and a row of several denticles beginning 

 at the apex and descending one side ; cleft spines set far down the joint, six in number 

 on the first two pairs, five on the third, seemingly with nearly equal branches, though 

 as the tips of these branches easily get broken, it is not safe to speak positively on this 

 point ; joints of the rami from sixteen to eighteen. 



Uropods. — Peduncles of the first pair longer than the rami, with two strong apical 

 spines besides the smaller marginal ones, the rami a little curved, the outer rather shorter 

 than the inner, both with a few marginal spines and a group within the cavity formed by 

 the producing of the outer margin to a point beyond the inner ; peduncles of the second 

 pair subequal in length to the rami, which are broader than those of the first pair, but 

 respectively not so long, spined in a similar manner, the outer a little shorter than the 

 inner ; peduncles of the third pair shorter than the rami ; the rami broad, lanceolate, but 

 with slightly emarginate apices, the outer longer than the inner, equal in length to the 

 outer of the first or the inner of the second pair, with spines at five points on each 

 margin, of which the outer is serrate ; each ramus has spines at the apex, the outer has 

 also a group on the outer margin near the apex, otherwise its margins are smooth ; the 

 first pair reaches back nearly as far as the third, the second falling short of both. 



Telson reaching beyond the peduncles of the third pair, cleft nearly to the base, its 





