REPORT ON THE AMPHIPODA. 1311 



three such spines at the apex behind, and three or four on the outer surface ; the third 

 joint with the serrate hinder and distal margins fringed with spines ; the wrist as broad 

 as the first joint, a little longer than broad, with spines along the convex front margin 

 and the parallel ridge and the shorter hind margin, and thickly set on the inner surface 

 of the sinuous distal margin, either end of which is rounded and serrate : ^he hand much 

 shorter than the wrist, scarcely half as broad, narrowing to a slig 1 ■''_, emarginate apex, 

 the margins slightly serrate, the hinder nearly straight, finely pectinate, both fringed 

 with spines ; the inner surface having about thirty flexible spines distributed over it ; 

 the finger nearly straight, slender, more than half the length of the hand, its inner 

 margin a little pectinate. 



Second Gnathopods. — Side-plates similar to the first pair. Branchial vesicles oval, 

 about half as long but not nearly half as broad as the marsupial plates. The marsupial 

 plates are similar in appearance to branchial vesicles, much broader than the first 

 joint, but not half its length, smooth, without setse, of which, however, the eventual 

 production is perhaps indicated by markings round the margin. The first joint 

 longer than that of the first gnathopods, but less broad, not quite so long as the wrist 

 and hand together, with some slender spines along the front margin, the adjoining ridge 

 without spines, the hind margin with a few ; the second joint with some spinules on the 

 hind margin ; the third joint shaped as in the preceding pair, but with fewer spines ; the 

 wrist elongate, widening a little distally, with six small spines on the front margin, two 

 on the straight hind margin, and about ten on the distal margin ; the outer surface has 

 two longitudinal ridges, of which the hinder carries a few spinules ; the hand elongate, 

 narrower and shorter than the wrist, tapering to an emarginate apex, with eight spinules 

 along the front margin, the outer surface with two slight ridges, the inner carrying about 

 a dozen small spines ; the finger slender, not a third the length of the hand. 



First Perseopods. — Side-plates broad and shallow, like the preceding pairs narrow in 

 front. Branchial vesicles like the preceding pair. The marsupial plates larger than 

 the preceding pair. The outstretched limb two-thirds of an inch long. The first joint 

 longer than in the preceding limbs, with about twenty-four spines along the hind margin, 

 fewer on the front, the adjoining ridge unspined ; 'the second joint longer than broad, 

 without spines ; the third joint longer than the fourth, shorter than the fifth, with small 

 spines along three edges ; the fourth joint with spines along both margins, and a row 

 along the under surface, the two longitudinal ridges of the upper surface without spines ; 

 the fifth joint narrower, gently curved and tapering, with two ridges along the upper, 

 and one along the under surface, the concave hinder margin carrying about twenty-seven 

 minute spines, and the inner surface a row of fewer spines ; the finger slightly bulbous 

 at the base, slender, a little curved, about a seventh part of the length of the fifth joint. 



Second Perasopods similar to the first, but with the side-plates larger, the branchial 

 vesicles very much larger, ecmal to or exceeding the size of the marsupial plates, and the 



