REPORT ON THE AMPHIPODA. 627 



which represents the two halves much flattened out; inner j)late reaching a little beyond 

 the first joint of the palp, having three teeth on the apical margin, the plumose setae 

 commencing near the middle of the inner margin, and passing round to the outer comer 

 of the apical margin, but not continued down the outer edge ; none of them large ; 

 the outer plate reaching much beyond the second joint of the palp, its inner border 

 (beginning from the base) carrying a cilium, then a setiform spine, then a spine, then 

 two microscopic teeth, then a close row of thirteen small teeth, those at the curve of 

 the apex being the largest, beyond these the curved outer margin apparently quite 

 naked ; there is a row of five little spines on the side of the plate, a little removed 

 from the inner margin ; of the palp-joints the first is longer than the third, the second 

 longer than the first, the fourth or finger provided with a sharp nail. 



First Gnathopods. — Side-plates very little dilated below ; first joint almost straight, 

 sparingly setiferous in front ; third joint with the emarginate front border much shorter 

 than the hind border, which has a group of setse near the aj)ex ; the wrist rather longer 

 than the hand, nearly half of its hinder margin coinciding with the distal margin of the 

 preceding joint, the remainder parallel with the front margin, slightly furred and carrying 

 two groups of setae ; the hand almost parallel- sided, like the wrist having some groups of 

 setse near the front border, and a conspicuous group at its apex, on the hinder border 

 having four groups ; the sloping, rather convex palm, microscopically pectinate, defined by 

 a spine, bordered with spiniform cilia, in addition to two linear groups of setae, and close 

 to the hinge of the finger two minute spines; the finger, besides the usual cilium on the 

 back near the hinge, has one about the middle of its inner margin ; this margin develops 

 a small tooth near the origin of the nail, two cilia taking rise at this point. 



Second Gnatho]yods. — Side-plates and the first joint of the leg a little longer and 

 narrower than those of the preceding segment ; branchial vesicle with a broadly rounded 

 upper lobe rising above the neck, the central part of the vesicle having the twist of a 

 screw, the lower part narrowing rather abruptly ; ^ marsupial plate narrow ; second joint 

 as long as the wrist ; third joint short, furred behind, apically somewhat rounded, and 

 carrying a group of pectinate spines; wrist much longer than hand, densely furred 

 behind, less so in front ; pectinate spines near the lower end of the hinder margin ; 

 hand long-ovate, densely furred, numerous pectinate spines of very various sizes arrayed 

 on both borders, especially in front apically, the pectination and curvature in both sets 

 being directed towards the finger ; the finger itself, as so commonly in this family of the 

 Amphipoda, minute, almost lost in the surrounding forest of spines, broad at the base, 

 then narrowing suddenly, the inner edge of the narrowed part microscopically pectinate 

 and produced into a tooth, over which the nail bends, with cilia at its base ; there is also 

 a cilium on the back of the finger. 



1 The figure, PI. VIII. gn. 2., unfortiin.ately does not show or even suggest the details above described, but only 

 gives the shape of the vesicle flattened out and mounted on a slide for the microscope. 



