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



third joint armed on the inner and apical margins, and on the upper part of the 

 outer maro-in ; the finger slender, slightly curved, in conjunction with its long spine- 

 like nail fully equalling the length of the third joint ; there are two cilia at the base 

 of the nail on the inner side. 



First Gnathopods. — Side -plates broad, expanded below, with a score of cilia round 

 the lower margin. First joint rather broad, reaching below the side-plate, with some 

 setje near the centre of the convex hind margin and at its apex ; second joint shorter 

 than the third, the front, or properly lower, margin of which adjoins the hind margin 

 of the wrist; the hinder margins of the third joint and of the wrist have setse on the 

 lower part ; the hand is broad, with the front margin continuing the curve of the wrist 

 and then becoming almost straight, giving a length to the hand not jnucli le.ss than 

 that of the first joint, the hind margin being very much shorter, ending in a very 

 shallow tooth carrjdng a long palmar spine, the palm being convex, very oblique, 

 ciliated ; a few small setaj are on the surface of the hand, and one on each lateral 

 margin, besides longer ones at the front apex ; the hnger is curved, reaching to the 

 cavity between the tooth and convex margin of the palm, and carrying a short dorsal 

 cilium near the middle. 



Second Gnathopods. — Side-plates oblong, the hinder margin straight, the front a 

 little sinuous, the lower furnished with a dozen setae. The marsupial plates narrow, as 

 long as the side -plates, with long seta3 on the front and apical margins. The first joint 

 of the limb broad, reaching the lower border of the side-plate, with six long setae on 

 the central part, and a tuft at the apex, of the hind margin, the limb in general similar 

 to that of the first gnathopods, but more massive, the wrist relatively smaller, the tooth 

 of the palm larger, and the following palm-margin sinuous, being at first concave and 

 then convex; the hand in front subequal in length to the first joint. 



First Pera?opods. — The side-plates similar to those of the preceding segment, but 

 larger, with fifteen seta3 on the lower margin. The first joint reaching the lower 

 margin of the side-plate, carrying four long setae at the centre, and as many in a group 

 at the apex, of the hind margin ; third joint broad and long, l)ut not as long as the 

 fourth and fifth together, with numerous setae along the hind margin and a tuft at 

 the apex in front ; the fourth joint oval, shorter than the fifth, bordered behind with 

 numerous spines, those near the apex being longer than the fifth joint ; the fifth joint 

 narrow, of even width throughout, slightly curved, bordered behind with spines ; the 

 finger slender, curved, more than half the length of the fifth joint. 



Second Perseo'pods. — The side-plates very broad, broader than long, not deeply 

 excavate behind, with four and twenty short setae on the lower margin. The first joint 

 not reaching the end of the side-plate, with half a dozen setas on the hind margin, the 

 lowest two very long, some short setge on the upper part of the front margin ; the limb 

 in general similar to that of the first peraeopods. 



