REPORT ON THE AMPHIPODA. 11(31 



straight ; the hind margin somewhat more evenly convex, converges to the narrowed 

 distal margin, which is nearly straight, projecting in front beyond the second joint, 

 parallel with a continuation of the hind margin, which crosses the surface just below the 

 neck ; near the convex part of the front margin, a curved slit crosses the outer surface 

 of the joint nearly halfway ; the second joint longer than broad, with one or two setules 

 on the hind margin ; the third joint longer than the fourth, widening distally, with 

 feathered spines at the apex of the convex front, and at three points of the straight hind 

 margin, one at its apex elongate ; the fourth joint not longer than the second, with spines 

 at the apex in front, and at two points of the hind margin ; the fifth joint subequal in 

 length to the third, narrowing distally, with feathered setse at the apex of the very con- 

 vex front margin and a spinule above, and setas at four points of the straight hind 

 margin ; the finger three-quarters the length of the fifth joint, rapidly tapering, curved, 

 with an opening in the apex. 



Second Perasopods. — The side-plates with a front lobe as in the preceding pair. 

 The branchial vesicles larger than in the preceding pair. The first joint with the front 

 margin evenly convex, making the plate more regularly oval than in the first peraeopods, 

 less broad above but equally long ; in this pair the third joint is nearly as long as the 

 fourth and fifth united, and the fourth is quite as long as the fifth ; the limb otherwise 

 nearly as in the preceding pair. 



Third Pereeopods. — The side-plates much broader than deep, having the convex 

 lower margin of the front lobe bordered with feathered setules, the small and shallow 

 hind lobe having a cilium in a notch of the lower margin. The branchial vesicles much 

 smaller than the preceding pair. The first joint irregularly squared, as broad as long, 

 but rather broader above than below ; the second joint broader than long ; the third 

 distally as broad as the length, the front margin convex, with small spines at the apex, 

 the hind margin nearly straight, with three strongly plumose spines at the slightly 

 decurrent apex ; the short fourth joint almost embedded in the third, than which it 

 is abruptly much narrower, distally broader than long, the hind margin very convex, 

 its rounded apex furred and carrying a feathered seta, the apex in front rounded, 

 carrying two or three setules ; the fifth joint almost as long as the third, tending to 

 oval, but with the hind margin almost straight, carrying a small seta above the apex, 

 the front margin convex, smooth, with two setse at the apex ; the finger very short, 

 stout at the base, with a broad sharp nail abruptly upturned behind, there being a 

 small dorsal cilium near the base of this nail, and still nearer two little dorsal teeth. 



Fourth Perseopods. — The side-plates not very unlike the preceding pair in outline, 

 but smaller and with smooth edges. The branchial vesicles very small. The first joint 

 narrower and longer than in the preceding pair, more oval than square ; the second joint 

 scarcely longer than broad ; the third much longer than the fourth, a little widened 

 distally, with a setule at the apex of the almost straight hind margin, one at the middle 



(ZOOL. CHALL. EXP. — PART LXVII. — 1888.) Xxx 146 



