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



Upper Lip with the distal border slightly emarginate. 



Mandibles with the trunk broad, the cutting edge slightly angled and divided into 

 about seven teeth ; the secondary plate on the left mandible with six teeth, its breadth 

 almost as great as that of the principal plate ; the secondary plate on the right 

 mandible less broad and much less strong than the principal plate, its distal edge 

 minutely denticulate ; the spine-row begins with three short spines, of which the first 

 is laminar, with a widened denticulate distal edge, a short ciliated space is followed 

 by a fourth spine pointing backwards and ending in two unequal teeth ; of molar 

 tubercle there appears to be no trace ; the palp is broad, set well forward, the first joint 

 longer than broad, the second joint broad and long, with a couple of setules near the 

 apex of the inner margin, the third joint much shorter and narrower than the second, 

 apically pointed, with two spines or setae on the inner side of the apex. 



Lower Lip broad, the somewhat narrowed and lightly ciliated apices of the principal 

 lobes standing wide apart, their inner margins sinuous ; the mandibular processes short, 

 apically narrowed and rounded. 



First Maxillie. — Inner plates small, oval, with one or two hairs observed on the 

 apex ; the outer plates broad at the base, the obliquely truncate distal margin carrying 

 seven spines, the innermost with five lateral teeth, followed by two other slender spines 

 apparently with fewer lateral teeth ; in the parallel row the two innermost spines are 

 furcate, the inner branch or tooth being the longer, the other two spines have a single 

 denticle on the inner side ; the palp is one-jointed, tapering, reaching beyond the outer 

 plate, having two small spines on the apex. 



Second Maxillse. — The inner plates much shorter and a little broader than the outer, 

 with two spines on the apex ; the outer plates with three spines on the apex. 



Maxillipeds. — Inner plates small, scarcely reaching the base of the palp, carrying a 

 spine on the upper part of the inner margin, a spine-tooth at the inner apex, with a 

 slender curved spine on the outer curve of the distal margin ; the outer plates narrowed, 

 reaching as far as the distal end of the first joint of the palp, with a small not pointed 

 spine near the middle of the inner margin, a spine-tooth in an indent just below the apex, 

 accompanied by a slender spine, and a second spine-tooth at the apex ; the first joint of 

 the palp is broad, with one or two spinules on the inner margin ; the second joint is 

 rather broader and longer, with eight marginal or sub-marginal spinules ; the third 

 joint is shorter and narrower than the first, the outer margin produced into a pointed 

 cap over the base of the finger, the apex and part of the inner surface carrying some 

 finely pectinate spines ; the finger is curved, longer than the third joint, with a small 

 dorsal cilium near the hinge, and a cilium at the base of the short sharp nail. 



The triturating organ of the stomach shows a group of some eight broad spines, 

 distally thorny. 



Fit^st GnatJiopods. — The side-plates broader below than above, the rounded lower 



