1026 THE VOYAGE OF H.M.S. CHALLENGER. 



some short setse besides the usual long one; the process over the molar tubercle is 

 lono- and conspicuous; the first joint of the palp, immediately above this, is short, 

 widenino- distally ; the second joint is moderately long and straight, and, besides setse 

 alono- the inner margin, has a succession of groups upon the inner surface, that near 

 the apex containing a row of some ten very long setse ; the third joint is longer than 

 the two preceding united, has four or five groups of setse on the outer surface near the 

 convex outer margin ; the inner margin is sinuous, forming with the outer a sharp apex ; 

 not far from the base it presents a groove or fold, about the middle of which begins a 

 marginal row of short pectinate spines, more than seventy in number, succeeded by six 

 lono- ones which carry the series to the apex. 



Lower Lip. — Mandibular processes large, rounded at the ends. 



First Maxillse. — Inner plate oval, small and narrow, with a plumose seta on the 

 apex, and below it three or four setules ; outer plate with seven spines on the oblique 

 truncate apex, the three innermost spines having from five to seven long denticles 

 towards the upper part, the others five or fewer ; the second joint of the palp rather wide, 

 reaching beyond the outer plate, having round its convex dentate margin ten thin spines, 

 the apical pectinate on both edges, and eight submarginal spines. 



Second Maxillse. — -The inner plate rather shorter and narrower than the outer, the 

 rounded distal margin fringed with spines, the series not reaching the outer margin, and 

 bounded by plumose setse just at the top of the straight inner margin ; the spines round 

 the apical margin of the outer plate descend the convex outer margin a little way. 



Maxillipeds. — The prismatic inner plates reach as far as or a little beyond the first 



joint of the palp ; the plumose setse commencing on the inner margin number about ten, 



the pectinate spines which fringe the apical border number about thirteen ; there is also 



a long submarginal spine-tooth near the inner apex ; the outer plates reach beyond the 



middle of the second joint of the palp, and are fringed along the inner margin, round the 



apical, and a short way down the outer margin with about thirty-two spines, of which the 



outer five are setiform, the apical ten elongate, curved, the remainder moderately long, 



straight, spine-teeth ; the first joint of the palp is very short, the second considerably 



more than twice as long, fringed on the inner border with many slender spines ; the third 



joint much longer than the first, with groups of spines on the inner margin, the adjoining 



inner surface, and the distal part of the outer margin ; the outer distal end is prolonged 



over the base of the finger in a short, ciliated, round-ended process ; the finger is long, 



with a sharp nail having two or three setules at its base ; the dorsal cilium small, near 



the base of the finger. 



First Gnathopods. — Side-plates much outdrawn in front, lower margin carrying 

 some setules. First joint reaching beyond the side-plate, rather broad, widest distally, 

 carrying long setse on both margins at the upper part, an apical group of pectinate spines 

 on the convexly bent hind margin ; a larger group on the hind apex of the short second 



