REPORT ON THE AMPHIPODA. 1363 



Second Gnathopods similar to the first but longer ; the first, second, and third joints 

 a little longer and very noticeably wider than in the preceding pair ; the fourth, fifth, and 

 sixth joints very decidedly longer ; from the tendency in this pair to turn back towards 

 the mouth-organs, it is not easy to lay them flat for a profile view, and in a ventral 

 view the tooth near the apex of the wrist does not project, so that the joint appears 

 altogether linear- 



First Pereeopods. — A narrow tooth or process projects from the segment above each 

 of these limbs, which are very much longer and broader than the gnathopods. The first 

 joint not quite so long as the third and fourth together, its front margin straight and 

 smooth, the hind margin with one or sometimes two little teeth ; the second joint longer 

 than broad ; the third more than twice as long as the second, with its hind margin nearly 

 straight, the front a little convex ; the fourth joint not twice as long as the third ; the 

 fifth joint narrow, tapering, almost straight, nearly three times as long as the third, 

 produced into a spine-like process along the proximal half of the minute finger ; there are 

 small setules or hairs at intervals along the hind margin of the limb. 



Second Per&op>ods. — Branchial vesicles narrowly oval, less than half the length of 

 the first joint. The first joint broader and a little longer than in the preceding pair, the 

 hind margin having a tooth at the centre (or, as on one of the limbs, below the centre), 

 another at the apex, and two intermediate ; the second joint with the apex of the hind 

 margin slightly acute ; the third and fourth joints nearly as in the preceding pair, the 

 fifth joint only equal in length to the fourth, otherwise with the finger as in the 

 preceding peraeopods. 



Third Permopods. — Branchial vesicles rather larger than the preceding pair. First 

 joint a little longer and much wider than in the second peraeopods, the front margin 

 having six or seven little teeth, the hinder margin smooth, but dividing near the apex 

 to form two little apical teeth ; the second joint comparatively stout, with two little teeth 

 on the front margin ; the third joint not twice the length of the second, with convex 

 hind margin, the front margin having three or four teeth, the lowest the largest ; fourth 

 joint less than twice the length of the third, with smoothly convex hind margin, the 

 front margin having six or seven unequal teeth ; the joint widens downwards to the fourth 

 and largest tooth, below this having two or three teeth, on what may be considered as 

 the palm margin; the anterior distal part of the joint containing gland-cells; the fifth 

 joint finger-like, slender, curved, about three-quarters the length of the fourth joint, the 

 largest tooth of which could impinge against the fifth joint about at its centre ; the finger 

 minute, sharp-tipped, thick at the base, which is inserted in the narrowed apex of the 

 fifth joint. 



Fourth Perseopods. — Branchial vesicles rather larger than the preceding pair. First 

 joint of the limb shorter than in the first perseopods but rather wider, longer than the three 

 following joints together, the margins convex and smooth, the front one having a little 



