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



margin ; the finger more than half the length of the fifth joint, with a small cap projecting 

 little beyond its bent tip. 



Second Perseopods. — Side-plates nearly as broad as long, very slightly excavated 

 behind, with only two or three sette on the lower margin. Branchial vesicles broader 

 than in the preceding pair. First joint not reaching the end of the side-plate ; the limb 

 not materially differing from the first perasopods. 



lliird Perieopods. — Side-plates broad, front lobe shallow, hinder much deeper. 

 Branchial vesicles broader but perhaps a little shorter than those of the preceding 

 segment. The first joint evenly expanded, longer than broad, the front margin rather 

 sinuous, armed with some long setae near the lower apex, the hind margin smoothly 

 convex, with a minute cilium here and there, the lower rounded behind and overlapping 

 the short second joint; the third joint as long as the fifth; the fourth joint a little shorter 

 than either, and in breadth intermediate; all these three have setae or spines on the front 

 margins and at the apices both behind and in front ; the finger slender, acute, but little 

 shorter than the fifth joint. 



Fourth Perseopods much longer than the third or fifth. Branchial vesicles small, of 

 rounded oval shape. First joint large, wider above than below, longer than wide, front 

 margin convex, with small cilia on the upper part, but most of it fringed with groups of 

 long setae, the long hind margin nearly straight, interrupted only by three or four minute 

 cilia, the lower margin rounded and overlapping the second joint behind ; the third joint 

 exceeding the fourth in length, the fourth the fifth, and the fifth the sixth, about equally 

 in each case, not greatly ; the third armed on both margins, the fourth only on the front, 

 the fifth on neither, but all on the apices before and behind ; the finger slender, curved at 

 the tip, with a little cap upon it. 



Fifth Perseopods. — Side-plates small. First joint of the limb greatly expanded, espe- 

 cially below, breadth greater than the length, lower margin behind descending far below 

 the almost straight front margin, which has two or three setae, three or four cilia and an 

 apical spine ; part of the hinder and of the lower margin is serrate ; the third joint a 

 little longer than the fourth, has a straight hind margin with two spines at, and one a little 

 above, the apex ; the hind margin of the fourth joint is convex with similar armature ; 

 l)oth of these joints carry setse or splines in front and are laid back against the wing of 

 the first joint, not nearly reaching its hind margin ; the fifth joint shorter and much 

 narrower than the fourth, has two convex smooth margins, and a lower margin cap-like 

 over the hinge of the finger with a minutely pectinate edge ; the finger is as long as the 

 fifth joint, or as its apical spines. 



Pleopods. — The peduncles have, together with a plumose seta, a pair of coupling 

 spines with very slender stalks on small basal bulbs ; these spines have three minute 

 retroverted teeth and an apical hook ; the cleft spines are three in number, one arm of 

 the cleft much longer than the other ; the joints of the rami number from nine to eleven. 



