1216 THE VOYAGE OF H.M.S. CHALLENGER. 



Eyes doubtful, apparently small, round, composed of few ocelli, situated on the lateral 

 lobes of the head. 



Upper Antennas. — First joint rather thick, longer than the head, narrowing a little 

 distally, and carrying a few spinules ; the second joint longer and thinner, with a 

 comparatively long spiue high up on the surface and another at the apex, and having the 

 surface, at least on one side, studded with rows of spinules, besides having in common 

 with the first joint a generally roughened hairy appearance all over. The other joints 

 missing. 



Lower Antennas. — First two joints very short, the gland-cone short, decurrent ; the 

 third joint rather stout, longer than the united first and second, carrying a few spines 

 and spinules. The other joints missing. 



Upper Lip with the distal margin not quite symmetrically emarginate, the round 

 tract on either side of the emargination carrying some short spine-like cilia directed 

 inwards. 



Mandibles. — The cutting edge divided into six or seven teeth, the most prominent 

 not being the outermost ; the secondary plate of the left mandible (on the right of the 

 Plate) is divided into four strong teeth ; on the right mandible this plate is less stout, 

 with small teeth ; the spines of the spine-row vary in number from seven and eight 

 on one specimen to ten and eleven on the other, all appearing linear when seen edge- 

 ways, but those near the cutting plates having in reality a broad shaft, widening for 

 some distance from the base, and then rather abruptly narrowing to a serrate linear 

 termination ; the molar tubercle large and prominent, with some strong teeth round part 

 of the rim of the dentate crown, a plumose seta and (observed only in one specimen and 

 only in the right mandible) a small dentate process on the outer side of the trunk of the 

 tubercle ; the palp is long, the first joint short, scarcely longer than broad ; the second 

 joint elongate, with many lightly feathered spines along the inner margin and on the 

 surface; the third joint shorter than the second, but nevertheless elongate, with the outer 

 margin convex, the inner nearly straight, carrying long feathered spines at intervals, the 

 almost acute apex having two or three ; there are also spines along the surface, most of 

 which are smaller than the marginal spines. 



Lower Lip. — The outer and inner lobes and mandibular processes not showing any 

 striking peculiarities, but not well enough observed for description. 



First Maxillw. — The inner plate with nine or ten very long plumose setse on the 

 sinuous inner margin ; the outer plate with ten spines on the truncate distal border, 

 the innermost spine straight, with some minute lateral teeth, the next shorter, with a 

 small denticle on the outer side, the following pair similar to these two ; in the centre 

 there are two, which each have a short and a long lateral denticle on the inner margin, 

 while between them in the adjacent row is a longer spine which has only little teeth if 

 any; of the three outermost spines, which as usual are rather stronger than the rest, one 



