<510 THE VOYAGE OF H.M.S. CHALLENGEK. 



on the two borders and the sides of the hand. The finger has a denticle on the inner 

 margin. 



Second Gnathopods. — Side-plates widened below, the front, hind, and lower margins 

 almost straight ; the first joint fringed with seta3 behind, parallel-sided, distally bending 

 backwards ; second joint as long as the wrist, third with the anterior margin short, the 

 posterior much rounded, furred, with several long setae near the rounded apex ; the 

 wrist a good deal longer than the hand, the front margin distally furred, and carrying 

 long setae near and at the apex ; the hinder margin furred nearer to the third joint, and 

 carrying eleven groups of setae increasing in length successively to the apex ; the hand 

 much longer than broad, much furred, armed with the usual spines, narrowing a little 

 distally, the finger comparatively long, occupying almost all the apical margin, its 

 terminal portion not much crooked. 



First Perseoiiods. — Side-plates similar to those of the preceding segment, but larger. 

 First joint strong, carrying setae on the hind margin ; third joint large, nearly as long as 

 the first joint, having groups of setse, short mixed with long, on the hinder border; 

 fourth joint somewhat shorter, much narrower, armed with spines and setas, narrowing 

 distally ; fifth joint as long as fourth, slender, a little curved, on the hind margin 

 carrying short spines and long ones, and close to the hinge of the finger a minute one 

 with a hook at the tip, bent toward the comparatively short finger. 



Second Perseopods. — Side-plates with front and lower margins straight, hinder 

 lunately excavate ; a small smooth ovigerous plate. The rest of the limb missing. 



Third Perseopods. — First joint much contracted below, at the upper part almost as 

 broad as the side-plate, though not appearing so in the full figure on the Plate, because the 

 side-plate is seen full, while the first joint is not quite full-face to the spectator ; its hind 

 margin is nearly straight, shallowly serrated, slightly concave below, while the front margin 

 is convex and spined all round ; third joint dilated, a little produced behind, with spines on 

 hinder rim ; both second and third joints have spines and setae on the front rim ; fourth 

 joint as long as the two preceding united, broader above than below, the front margin 

 with five pairs of short spines, each of the upper four pairs with a long seta between the 

 two spines, the fifth pair without a seta, a sixth apical pair with a long spine intervening ; 

 the fifth joint thinner than the fourth, equal in length, straight, with five pairs of spines 

 on the front margin ; finger rather short. 



Fourth Perwopods. — First joint oval, contracted below, closely spined on more than 

 half the front margin which is smooth above, the lower margin behind forming a narrow 

 lobe instead of a broad one as in the third peraeopods ; setae and spines on the front rim 

 of the short second joint ; the remaining joints similar to those of the preceding pair, but 

 each longer than the corresponding one in that pair ; the finger missing. 



Fifth Peraeopods. — First joint of uniform breadth all along, front margin slightly con- 

 cave, spines increasing in size towards the lower end, and the serrations of the hind margin 



