1262 THE VOYAGE OF H.M.S. CHALLENGER. 



Mandibles. — The cutting plate divided into five or six strong teeth, of which one or 

 two are much more prominent than the rest ; the secondary plate on the left mandible 

 similar to the principal, divided into four or five teeth ; on the right mandible the edge 

 of this plate seems to be rather denticulate than cut into regular teeth, but this may be an 

 effect produced by wear in the actual specimen examined ; spine-row consisting of three 

 serrate spines on the left mandible, of two on the right ; the molar tubercle powerful, 

 ciliated, apparently not strongly denticulate, presenting an angular prominence on the 

 side near the spine-row. 



Lower Lip.— The principal and inner lobes strongly ciliated; the mandibular pro- 

 cesses narrow. 



First Maxillae. — Inner plate wanting ; outer plate carrying seven strong spines, of 

 which four are furcate with some serration of the edges, the others are more or less 

 denticulate ; the first joint of the palp is short, with a seta at the outer distal angle ; the 

 second joint is long, widening distally, and there cut into seven or eight teeth between 

 which are planted six spines, the outermost the longest ; on the inner margin and the 

 distal part of one surface there are several setae. 



Second Maxillse. — The inner plate shorter, but at the base wider, than the outer, 

 fringed with spines of various lengths round the apical margin and about to the centre of 

 the inner ; the outer plate with longer spines on the apical margin, and none on the 

 straight inner margin. 



Maxillipeds. — The inner plates narrow at the base, not reaching the apex of the first 

 joint of the palp, with numerous feathered setae on the inner surface between the centre 

 of the inner margin and the centre of the apical ; the apical margin broad, irregular, 

 sloping inwards, carrying numerous feathered setae, and near the outer corner a spine- 

 tooth, together with one or perhaps two such near the inner corner ; the outer plates 

 small, just reaching beyond the apex of the first joint of the palp, the inner margin 

 serrate, carrying some setae and five rather distant spine-teeth ; distally there is an 

 emargination which may be reckoned either to the inner or apical margin, carrying two 

 slender spines, the distal one stronger than its neighbour ; the first joint of the palp 

 shorter than any of the three following, with setae on its inner margin ; the second joint 

 stoutest near the base, not twice as long as the first, fringed with slender setae on the 

 inner margin, the third joint almost as long as the second, with numerous long setae or 

 setiform spines, especially about the inner margin and apex ; the finger as long as the 

 third joint, curved, ending in a very sharp point, the inner margin forming a small tooth 

 just in advance of the apex, its whole course finely pectinate, the surface also showing 

 two or three series of little curved markings pectinate on the lower convex side. 



First Gnathopods attached close to the maxillipeds. The first joint not longer than 

 the hand, with the front margin straight, the hinder convex, carrying some apical spines ; 

 the second joint with some spines a little above the hinder apex ; the third joint not 



