REPORT ON THE AMPHIPODA. 1437 



channelled behind, with the nearly straight front margin ending in a pointed apex, the 

 hind margins strongly convex, that of the inner surface the more extensive ; the third 

 joint much broader than long, short, cup-like to receive the fourth joint, the hinder 

 apex produced ; the fourth joint having its convex hind margin smoothly continuous 

 with that of the preceding joint, the front margin shorter, nearly straight, the distal 

 margin of great breadth, cut into six or seven graduated teeth, the foremost the largest, 

 the two next the hinge minute ; the narrow, slightly curved, fifth joint tapers a little, 

 and closes down upon the teeth just mentioned, reaching a very little beyond them (or 

 in some specimens not beyond them), and in combination with these forming a powerful 

 clasper ; the finger is slender, tapering, nearly straight, not half the length of the hand. 

 There are some minute spinules on the limb, chiefly on the front margin of the fifth and 

 on the teeth of the fourth joint. 



Fourth Perseopods much slighter in structure though not much shorter than the third. 

 Side-plates small and shallow. First joint nearly as long as that of the preceding pair, 

 which it resembles, widest just below the neck, much narrowed lower down, the front 

 margin very sinuous, pectinate below, a narrow lobe at the apex partly overlapping the 

 next joint, the hinder margin below the upper expansion nearly straight ; the second 

 joint short, channelled before and behind ; the third joint not longer than the second, a 

 little broader than long, pectinate in front, the hind margin convex, the inner surface 

 scabrous; the fourth joint oval, longer than the second and third together, narrower at 

 the distal end, the front margin a little unevenly convex, finely pectinate, the inner 

 surface strongly scabrous down the centre ; the fifth joint narrow, scarcely shorter than 

 the fourth, pectinate in front, furred behind, the hind margin with a little more convexity 

 than the front ; the finger slender, slightly curved, more than half the length of the fifth 

 joint, two-thirds of the inner margin pectinate. 



Fifth Perseopods. — The side-plates not distinct from the segment, which, it may be 

 mentioned, displays on either side when flattened out a singularly sinuous margin both 

 behind and before. The first joint attains its greatest width immediately below the point 

 of attachment, and thence narrows gradually to the distal end, with a straight hind 

 margin and slightly concave front one, the length being a little less than that of the first 

 joint in the preceding pair ; there are numerous conspicuous gland-cells along the centre ; 

 the remaining joints are feeble, together not nearly as long as the first, against which, 

 along the protecting ridge of its inner surface, they are commonly folded back ; the 

 second joint short, lying across and within the rounded and three-lobed apex of the first 

 joint ; the third longer, oval ; the fourth narrower than the third, but much longer ; 

 the fifth narrower than the fourth, shorter than the third, bent ; the finger little more 

 than half the length of the fifth joint, not pointed, but a narrow oval, the distal end 

 serrated with some minute retroverted teeth. In the female the first joint is similar 

 to that in the male, or with the hinder lobe of the apex a little more produced down- 



