REPORT ON THE AMPHIPODA. 1501 



shorter and more slender than the first of the upper antennae, second joint longer than 

 the first, third rather longer than the second, carrying one long marginal bristle ; the 

 first joint of the flagellum much shorter and narrower than the last joint of the peduncle, 

 carrying one marginal and one or two apical bristles, the second joint almost linear, 

 much shorter and narrower than the first, having some short bristles at its tip. 



Mouth Organs small and feeble ; the Epistome forming a dome broader than 

 deep over the mandibles ; the Mandibles narrow, narrowing towards the bent apex, 

 which on the left mandible has a bidentate appearance, the two teeth representing 

 the cutting edge and the secondary plate ; whether there is any secondary plate on 

 the right mandible is doubtful ; the palp, being a character of the male, was not 

 present. 



First Gnathopods. — Side-plates squared, the front angle rounded, carrying a bristle. 

 The first joint about as long as the third, fourth, and fifth together, widening a little 

 near the distal end, having three minute setules on the front margin ; second joint 

 scarcely longer than broad, with a bristle near its hinder apex ; the third joint subequal 

 in length to the wrist and rather wider, the front margin convex, the hinder straight, 

 with bristles at two points ; the wrist similar to the third joint, with bristles near the 

 front apex and at three points of the hind margin, of which the smoothly rounded apex 

 projects a little behind the hand ; the hand scarcely if at all longer than the wrist, 

 much narrower, tapering, the front margin convex, with a short bristle near the apex, 

 the front margin almost straight, smooth ; the finger short, curved, armed with a setule, 

 the tip bent, acute. 



Second Gnathopods. — Branchial vesicles longer than the first joint and wider, 

 narrow near the base, widening distally. Marsupial plates incompletely developed, 

 represented by a very small oval lamina. First joint longer than in the first pair, 

 not conspicuously widened at any part, quite as long as all the remaining joints 

 together, with a bristle at the hinder apex ; the second joint longer than broad, with two 

 bristles on the bent hinder margin ; the remaining joints as in the first pair but rather 

 longer, not wider, the third with bristles at four points of the hind margin, the wrist 

 with bristles at five points. 



First Perseopods. — Branchial vesicles and marsupial plates as in the second gnathopods 

 but rather larger. The first joint a little longer than in the preceding limbs, very 

 slightly widened towards the distal end ; the second joint longer than broad ; the third 

 narrower but rather longer than in the second gnathopods, similarly armed ; the fourth 

 joint much longer than the third, narrow, with a bristle at the apex of the slightly 

 convex front margin, and four along the straight hind margin ; the fifth joint slender, as 

 long as the fourth, bent at the neck, then a little widened, straight, tapering to a narrow 

 apex, with three bristles near the front, and four along the faintly furred or pectinate 

 hind margin ; the finger very small, about a fifth as long as the fifth joint. 



