1466 THE VOYAGE OF H.M.S. CHALLENGER. 



front margin convex, the hinder concave, the joint much narrower and more elongate and 

 with the gland-cells less conspicuous than in Platyscelus ovoides ; the fourth joint shorter 

 and narrower than the third, less curved ; the fifth joint straight, much shorter than 

 the fourth ; the finger small, narrow, curved, folding closely against the apical part of 

 the fifth joint, which at first bulges a little and is then narrowed, carrying one or two 

 quite minute spines or spine-like processes. 



Second Perseopods very similar to the first. 



Third Perseopods. — Side-plates forming a strong acutely projecting process ; within 

 them there is a small triangular process pointing backwards. First joint two and a half 

 times as long as broad, with the hind margin forming a long bow, the front a little 

 sinuous, faintly serrate, considerably longer than all the remaining joints together, much 

 of the surface showing scale-like sculpture ; the third joint stouter and a little longer 

 than the fourth ; the fourth with a little pectination at the distal part of the front 

 margin ; the fifth rather longer than the fourth, with the front margin finely pectinate ; 

 the finger minute. 



Fourth Perseopods. — First joint longer and very much broader than in the preceding 

 pair, with the front margin much excavate to receive the convex hind margin of the first 

 joint of the third perseopods, the hind margin very convex at the upper part ; then 

 nearly straight, channelled, with a short longitudinal groove of the sculptured surface 

 near and in front of the top of the channelled part, of which the inner margin is fringed 

 with setules ; second joint short and bent, considerably above the broad distal margin of 

 the first, and not reaching its hind margin ; the third joint longer and broader than the 

 fourth, having the front margin pectinate with teeth which as they approach the apex 

 are retroverted, the apex very slightly produced ; the fourth joint armed like the third, the 

 apex not produced ; the fifth joint little more than a third as long and less than a third 

 as wide as the fourth, straight, nearly smooth but with some extremely minute pectina- 

 tion of the front margin ; finger not observed. This limb and the preceding are figured 

 from the inner surface In fig. prpA, the fifth joint is missing only from a defect in 

 the specimen ; the groove of the first joint shows through from the outer surface. 



Fifth Perseopods. — The first joint as long as that of the second gnathopods, of 

 tolerably uniform breadth, curved so that the front margin is somewhat concave, the 

 hinder convex ; at the extremity of the front margin there are two or three quite minute 

 terminal joints. 



Pleopods. — The peduncles stout, strongly produced into a rounded lobe on the inner 

 3ide, the very small coupling spines being placed above this lobe ; the cleft spine not very 

 strong, with subequal arms, one of them having a slight subapical dilatation ; the inner 

 ramus with thirteen or fourteen joints, the outer with fourteen or fifteen. 



Uropods. — Peduncles of the first pair shorter than the rami, widening distally, set 

 as far apart as possible, the outer margin and outer corner of the distal margin pectinate ; 



