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



First Gnathopods. — Side-plates broad, much produced iu front below ; first joint 

 scarcely reaching to the lower rim of the side-plate, of nearly equal breadth throughout, 

 with setae on the front margin ; third joint short, triangular, hind margin convex, furred, 

 with set£e near the apex ; wrist stout, scarcely as long as the hand, with the front margin 

 almost adjoining the second joint, the hind margin where free a little furred, with setae at 

 the apex ; the hand at its base narrower than the wrist, distally scarcely broader than the 

 base of the finger, where it has a tuft of small spines or setae ; the borders are rather 

 sinuous (though considerably less so than in the figure gn. 1. c), with some setae on the 

 hinder one; the finger is short, very slightly curved, seemingly with no capacity for 

 bending against the hand ; it has a denticle like that in the finger of the maxillipeds. 



Second Gnathopods. — Side-plates widening gradually and slightly downwards ; first 

 joint as long as the third, fourth and fifth combined, distally widening and bending 

 backwards ; second joint rather longer than the wrist, third joint much shorter, narrow 

 at the base, then expanding, the very convex hinder margin furred, and having a group 

 of spiny setae near the apex ; the wrist starting with a narrow neck swells out and again 

 narrows somewhat apically ; it is densely furred almost all over, and has scale-like 

 ornaments on the breast ; the hand, narrow at the base, widens a good deal towards the 

 distal end ; it is densely furred, some of the cilia outstanding, others adpressed and grace- 

 fully waved ; near the palm on the breast some scales are conspicuous ; the convex palm 

 is set on both sides with minute straight cilia, and forms a recess with the apical portion 

 of the hind margin, into which the short finger closes down ; the finger, set at some 

 distance from the front margin of the hand, is thick at the l.iase, over-arched with many 

 spines set in rows upon the hand's front or apical margin, the spines of various lengths, 

 but each seemingly having a short tooth on the convex side before the apex is reached. 

 The branchial vesicles of this and the following pairs exhibit many cross folds or 

 pockets ; they narrow towards the distal end. 



First Perseopods, — Side-plates similar to those of the preceding pair; third joint 

 longer than fourth, apex produced downwards ; long, finely plumose setae on the hind 

 borders of both third and fourth joints, and a row of ten spines along the hind border of 

 the fifth joint, which equals the third in length ; the third, fourth and fifth are edged on 

 both borders with cilia apparently in simple rows, not thickly set so as to constitute 

 furring ; the finger curved, with clean edges, except for the dorsal cilium. 



Second Perseopods. — Side-plates broad, the excavation not carried far down, the joints 

 similar to those of the preceding pair, except that the fifth is a little shorter, with nine 

 spines instead of ten. The branchial vesicle with a large accessory pocket at the top. 



Third Perseopods. — Side-plates much broader than deep, broader below than above ; 

 first joint broad, rounded, the very convex front margin furred above, with long set« 

 below, some short spines on difi'erent parts ; the serration of the hind margin presenting 

 only five points above and three small indents lower down, each carrying a cilium ; the 



