REPORT ON THE AMPHIPODA. 1049 



breadth being about half its total length, the hind margin crowded as usual with spines, 

 many of them conspicuously pectinate at the centre, the inner surface having a series of 

 spines down the centre and another close to the front margin ; the hand, which is as long 

 as the free hind margin of the wrist, has its greatest breadth near the base ; both margins 

 are armed with many spines ; a dozen spines are arranged along the centre of the inner 

 surface ; the ringer is narrow, much curved, much more than half the length of the hand, 

 and inserted close to its hind margin ; the inner margin of the finger fringed with 

 eight or nine microscopically feathered spinules ; the nail long but not nearly half the 

 total length of the finger ; the dorsal cilium at a little distance from the hinge. 



Second Gnathopods. — Side-plates directed forwards, not wider below than above, 

 the hind margin almost straight, curving a little to the small apical tooth. The 

 branchial vesicles broad, not so long as the side-plates. The marsupial plates 

 narrow, longer than the branchial vesicles. The first joint curving forwards, expand- 

 ing distally, both margins fringed almost throughout with long setae ; the second 

 joint with two or three spinules on the hind margin ; the third joint with two convex 

 margins converging to the pointed apex, the spines on the inner surface near the front 

 margin being more numerous than those on the hinder margin ; the front margin of the 

 wrist nearly straight, and the free portion of the hind margin only slightly convex, 

 fringed as usual with many spines ; on the inner surface are several small groups of 

 spines near the front margin, and larger groups along it nearer the centre, set obliquely ; 

 the hand is much more than half the length of the wrist, but not so long as its free hind 

 margin ; its greatest width is not far from the base, where the spines of the hind margin 

 begin and may be considered as defining a palm ; besides the usual spines of the margins 

 and apex, the inner surface is thickly set with rows of pectinate spines, except near the 

 base and along the hinder part, which has only a few scattered spines ; the finger is 

 narrow, much curved, closely resembling that in Ampelisca chiltoni, not reaching the end 

 of the palm-margin. 



First Perxopods. — Side-plates directed forwards, of even breadth throughout, the 

 hind margin ending in a small apical tooth. The branchial vesicles and marsupial plates 

 like the preceding pair. The first joint long and rather narrow, curved forwards, 

 reaching a littfe beyond the side-plates, with some very long setae on the middle of the 

 convex hind margin ; the second joint short, with one or two apical spinules ; the third 

 long and almost parallel-sided, with marginal spinules and long feathered setae at seven 

 or eight points on each margin, the upper part of the front margin cpiite smooth ; the 

 fourth joint short, the hind margin fringed as usual, the front having three apical setae, 

 of which one is much longer than the following joint ; the fifth joint apically narrower, 

 twice as long as the fourth, with feathered setae at six points of the convex front 

 margin, a spine and a seta at three points of the sinuous hind margin ; the finger 

 slender, curved, a little longer than the two preceding joints united. 



(ZOOL. CHALL. EXP. — PART LXVII. — 1887.) XxX 132 



