1106 THE VOYAGE OF H.M.S. CHALLENGER. 



and curved, just reaching the end of the palm ; the inner margin smooth, but forming a 

 tooth just in front of the nail and bordered with a few small setules and tiny spine-teeth, 

 neither series projecting beyond the edge ; dorsal cilium as in the first gnathopods. 



First Perwopods. — Side-plates, branchial vesicles, and marsupial plates rather larger 

 than in the preceding segment, otherwise very similar. The first joint rather longer and 

 broader than in the second gnathopods, showing closely-packed gland-cells ; the second 

 joint short, with spinules at two points of the hind margin and a small group of slight 

 spines at its apex ; the third joint broad, well-packed with gland-cells, widest distally, 

 longer than the fourth joint, with spinules or spines at two points in front and three 

 behind ; the fourth joint not nearly twice as long as broad, with spines at four points of 

 the hind margin and the apex of the front ; the fifth joint longer than the third, with 

 spines at six or seven points along the hind margin and two on the convex front margin, 

 which like the preceding joint has also a spinule high up ; the finger curved, more than 

 half the length of the fifth joint, with an obvious aperture at the tip for the exudation 

 from the gland. 



Second Perteopods. — Side-plates, branchial vesicles, marsupial plates, and limb 

 scarcely distinguishable from those of the preceding segment. 



Third Per&opods. — Front lobe of the side-plates deeper than the hind one. Front 

 joint not much dilated, broader above than below; the front margin only slightly convex, 

 carrying small spines at intervals, and an apical group ; the hind margin very faintly 

 serrate and armed with spinules, and at the lower end a slender spine ; the second joint 

 with spines at two points of the front margin ; the third joint not long, but longer than the 

 fourth, with spines at two points of each margin, besides spinules at two points in front ; 

 the fourth joint with spinules at the centre and slender spines at the apex of the front 

 margin and spines and spinules at the apex behind; the fifth joint longer than the third, 

 with tolerably strong spines at four points in front and at two points behind ; the finger 

 strongly curved, half the length of the fifth joint, with a cilium at the base of the very 

 acute nail. 



Fourth Perseopods. — The front lobe of the side-plates a little deeper than the hinder, 

 with some spinules in front ; the hinder with a spine and spinule at the back. The limb 

 similar in many respects to that of the preceding pair, but with the joints longer; the 

 first joint with the hind margin concave below ; the second with spines only at the apex; 

 the third with spines at four points of each margin, the hinder being serrate and with 

 strong spines ; the fourth joint with two groups of strong spines in front, and a group at 

 the apex behind, one of short, the next of slender, the lowest two of long and strong, 

 spines ; the finger is much less than half the length of the fifth joint. 



Fifth Perseopods. — The side-plates small, not bilobed. The limb scarcely differing 

 from that of the fourth perseopods ; the first joint rather longer, with the hind margin 



