(J40 THE VOYAGE OF H.M.S. CHALLENGER. 



third broad, rather longer than either of the next following, with setiform spines on the 

 front apex and the hind margin ; fourth joint similarly armed, much broader than the 

 fifth joint, which is subequal in length to it and similarly armed, gently curved, attached 

 to the fourth joint at the anterior part of the distal margin ; finger as long as the fifth 

 joint, slender, curved slightly, and unarmed except for a minute dorsal cilium near the 

 hinge, and a cap to the nail, the cap being a little broader than the nail and pi'ojecting 

 slightly beyond it. In the figures giiA. andj^rj^.l. the nail is not shown. 



Second Peraeopods. — Side-plates not of anj^ unusual breadth below, the greatest 

 breadth being where the excavation ends about the middle of the plate, giving the 

 appearance of an upturned point ; the limb closely resembles that of the first 

 perseopods. 



Third Peneopods. — Side-plates rather small, broader than deep, neither lolje produced 

 noticeably below the other. Branchial vesicles not reaching the dimensions of those of 

 the first perseopods, broad above, narrow below, with a long and very narrow accessory 

 lobe and a short one. First joint ovoid, much broader above than below, front margin 

 with small spines, hinder with slight serrations, a lobe ascending at the top in front, 

 another descending behind ; third joint broader but considerabl)'^ shorter than fourth, 

 little decurrent, with spines on the front margin, and three on the hind margin, two 

 high up and one apical ; fourth joint broader than fifth but scarcely so long, with five 

 groups of spines on the front margin, the apical group containing five spines of difi'erent 

 lengths ; on the front margin of the fifth joint there are six or seven groups of sjaines ; 

 the finger is long, very slender, shorter than the hand ; the nail minute. 



Fourth Perseopods. — Side-plates not much smaller than the preceding pair. Branchial 

 vesicle with what appears to be an irregularly branched accessory lobe. First joint 

 narrower than in the preceding pair, scarcely wider above than below ; all the joints 

 except the finger longer than in the preceding pair, but otherwise very similar. 



Fifth Perseopods. — First joint large and long, of even breadth for some way dovm, 

 the hind margin then rather abruptly sloping forward, little serrate, the front margin 

 sinuous, little spined except at the lower part ; the third joint narrower than in the two 

 preceding pairs, the three spines on its hind margin much stronger ; the fourth and fifth 

 joints shorter and narrower than in the preceding paii-, each with a spine at the middle 

 of the hind margin, which is not found in either of the preceding pairs ; the armature 

 otherwise similar ; finger very slender. 



Pleojiods. — The two coupling spines on the peduncles have three retroverted teeth ; 

 the cleft spines on the inner ramus numbering seven in the first pair, six in the other 

 two pairs ; joints of the rami twenty-eight to thirty, the first joint of the inner ramus 

 longer than that of the outer. 



Uropods. — Peduncles of the first pair subequal in length to the rami, a little longer 

 than the inner, a little shorter than the outer, strongly spined on the upper margin ; 



