REPORT ON THE AMPHIPODA. U65 



Lower Antennse (of the male).— Third (first free) joint of the peduncle forming a 

 narrow neck, then widening till near the apex, which, however, is wider than the neck, 

 the edges smooth ; the fourth joint less than twice as long as the third, widened at the 

 distal end ; the fifth joint rather shorter than the fourth ; the first joint of the flagellum 

 less than a third of the length of the last of the peduncle, the second joint a very little 

 shorter than the first. 



Mandibles. — The trunk sinuous, the palp attached behind the centre; the cutting 

 edge with a rounded strongly projecting tooth at the upper corner, in the left mandible 

 the lower corner also projecting a very little flatly with denticulate edge, the intermediate 

 space striated and very minutely denticulate ; each mandible has a secondary plate, 

 triangular, with the front edge closely adjoining that of the principal plate and very 

 similar to it but of smaller extent ; on the left mandible there is an additional plate 

 overlapping the lower part of the secondary one, to which it is similar but smaller and 

 with undenticulate edge ; the first joint of the palp is considerably the longest, the 

 second a little longer than the third. 



First Maxillae. — The single plate has four teeth at the distal end of the inner margin. 

 Maxillipeds. — The outer plates broad, with sinuous inner margin and the apex 

 rounded, distally carrying a few setules. 



First Gnathopods. — Side-plates with the lower front angle acute, to which there runs 

 a ridge of the inner surface. First joint narrow near the base, then widening a little 

 abruptly with convex front margin carrying distant setules or slender spines ; second 

 joint with such spines on the lower part of the hind margin ; third joint wrist-like, 

 with slender spines along the hind margin, a few on the surfaces and on the lower part 

 of the front margin ; the wrist longer and much broader than the hand, with slender 

 spines distributed as on the preceding joint, but not on the lower part of the denticulate 

 hind margin ; the produced hinder apex forms a broad triangle, not as long as the hand, 

 having a dozen little teeth on the inner or front margin; the hand has about fifteen little 

 teeth on the hind margin, and two or three on the apex ; the finger is minute, little 

 curved. 



Second Gnathopods. — Side-plates with the lower hinder angle rounded and produced 

 a little backwards. The first joint longer than in the preceding pair, with the front 

 margin concave ; the third joint longer than in the first gnathopods, and the wrist con- 

 siderably longer though but little broader, with numerous spines on the inner surface, 

 the produced apex nearly as long as the hand, with about twenty teeth on the inner 

 edge ; the hand a little longer than in the preceding pair, with about twenty denticles on 

 the hind margin, and two or three on the apex ; the finger as in the first pair. 



First Perseopods. — Branchial vesicles very large. First joint longer than that of the 

 second gnathopods, with a narrow neck, then widened, with convex hind margin ; second 

 joint longer than broad; third joint curved, elongate but shorter than the first joint, the 



(ZOOL. CHALL. EXP. — PART LXVII.— 1888.) Xxx 184 



