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



much bowed, with a couple of small spines at the apex, and another a little higher 

 up ; the fourth joint rather shorter than the fifth, slender, a little curved, with spines 

 at four points of the hind margin ; fifth joint as long as the first, slender, a little 

 curved, with spines at three points of the hind margin ; finger slender, much curved, 

 acute. 



Second Perseopods. — Side-plates like the preceding pair, but larger. Branchial 

 vesicles considerably longer than the first joint of the limb, of nearly even width through- 

 out, the margins irregular ; the first joint extending less beyond the side-plate, because 

 of the greater size of that plate ; the limb scarcely distinguishable from that of the 

 preceding pair except that the joints from the third to the sixth are rather longer. 



Third Perseopods. — Side-plates bilobed, broader, and at the hinder lobe deeper, than 

 the preceding pair. Branchial vesicles longer than the first joint of the limb. The first 

 joint a broad oblong-oval, rather longer than the first joint in the preceding pair, with 

 small spines at two points on the front margin and at its apex, and one or two spinules 

 on the hind margin ; second joint short, with its hind lobe not decurrent but pointing 

 downwards ; third joint shorter than the first, the breadth about half the width, 

 spines at two points on the straight front margin and at its apex, and with a similar 

 distribution on the convex hind margin ; the rest of the limb missing. In a second mounted 

 specimen the perseopods were all broken at the third joint, but the fragments indicated 

 that the third and fifth pairs were probably similar to the fourth, the third shorter, the 

 fifth longer. 



Fourth Perseopods. — Side-plates with a decurrent hind lobe. Branchial vesicles 

 scarcely so long as the first joint. First joint longer and broader than in the preceding 

 pair, wider above than below ; third joint longer than in the preceding pair, as long 

 as the first joint, the breadth one-third of the length, spines at four points on each 

 margin ; the fourth joint a little longer than the third, slender, slightly curved, with 

 spines at four points in front and two behind ; fifth joint much longer than the fourth, 

 slender, a little curved, with spines at five points on the front margin, some spinules at 

 four or five points behind, the distal end rounded below the apical spines of the front 

 margin ; finger slender, sharp, curved, with some minute cilia on the inner margin. 



Fifth Perseopods. — Side-plates small, not decurrent, the hind margin nearly straight. 

 Branchial vesicles very small. First joint much larger than in the preceding pair, the hind 

 margin nearly straight, much longer than the front, so that it descends below the second 

 joint, having a little incision at the lower corner with a small cilium in it ; there are 

 spines at the apex of the front margin and at two points above it ; the third joint nearly 

 as long as the first, with spines at four points on the front, and five on the hind, margin ; 

 its breadth not a third of its length ; the rest of the limb missing. 



Pleopods. — Coupling spines very small, with four or five small teeth ; cleft spines 

 few in number, apparently only two, with long arms, the inner nearly as long as the 





