REPORT ON THE AMPHIPODA. 839 



covering the basal joint of the legs. Mandibles ajsically only a little dentate, the third 

 joint of the palp straight, the molar tubercle of irregular shape, tolerably large, the 

 molar surface not circular. Maxillipeds with the outer plate large, reaching almost to 

 the apex of the second joint of the palp, its inner margin furnished with teeth, apioally 

 devoid of set^. The gnathopods subequal, the second pair more or less elongate ; the 

 wrist very long, generally equalling the length of the hand or longer than the hand, 

 produced into a short rounded heel." But as the characters ascribed to the side-plates 

 and the maxillipeds would be unsuitable to the Challenger species which I have placed in 

 the genus Ilalimedon, I feel bound to adhere to the definition of that genus given by 

 Boeck, who instituted it. 



Halimedon schneideri, n. sp. (PI. LIX.). 



Head about as long as the three following segments united, with a down-bent 

 apically subacute rostrum ; the lateral lobes of the head small and little produced ; the 

 back round, with a rather imbricated appearance in the specimen figured ; this was perhaps 

 accidental, as a second specimen showed but little of it, the second specimen having also 

 the segments of the perseon more regular, the hinder a little longer than the front ones, 

 and the seventh the longest ; the first four, and especially the first three, segments of the 

 pleon exceed in length those of the perseon ; the first three have the postero-lateral angles 

 rounded. 



Eyes not made out in the specimen figured, but in the second specimen, apparently 

 belonging to the same species, they are dark, elongate, broader in front than behind, not 

 reaching the tip of the rostrum, closely approximate the one to the other. 



Upper Antennw. — The first joint thicker than the second, in length subequal to it, 

 the second carrying some groups of setse ; the third much thinner and shorter than the 

 second, also carrying some long setae ; the flagellum of seventeen joints, of which the 

 first three or four together equal the length of the third joint of the peduncle, the first 

 six or seven its second joint. 



Lower Antennae. — The first joint not greatly expanded, the gland-cone small but 

 distinct, produced along part of the third joint ; the third joint about equal in length and 

 breadth, fourth joint longer and thicker than the fifth, both straight, and with numerous 

 groups of setae ; the flagellum tapering, of twenty-four joints carrying spine-like setaa. 



Upper Lip. — Both plates distally broad, the outer squared with rounded corners, and 

 quite smooth, the inner less broad at the distal edge but with its sides sloping back across 

 the corners of the outer plate and describing a curve beyond them, this plate also 

 apparently unciliated. In the figures the distal edge is uppermost. 



Mandibles. — Cutting plate strong, divided into three principal teeth, the centre one 

 flanked by two denticles ; the secondary plate on the left mandible strong, similar to 



