874 MRS. E, W. SEXTON ON AMPHIPODA [NoV. 23, 



is the same on both maxillfe, but the number of the auxiliary teeth 

 varies. Both plates and palp covered with fine hairs. 



Maxillipeds. — The 2nd and 3rd basal joints with fan-shaped 

 groups of long stout bristles on the outer side. 2nd and 3rd 

 joints of the pa^p each carrying on the inner side a longitudinal 

 row of cleft-tipped bristles and a number of small curved sensory 

 spines, similar to those on the gnathopods ; terminal joint in 

 the male ending in a distinct nail. 



Gnathopods. — Practically no difference between the gnathopods 

 of the full-grown specimens and those figured by Sars. The basal 

 joints in both gnathopods are considerably wider at the distal 

 end ; posterior margins convex, densely crowded with small 

 curved sensory spines, with 6-9 longer ones at the distal angle. 

 These spines develop at maturity, together with the calceoli and 

 sensory filaments of the antennae; young specimens, 4-5 mn)., 

 have none; older animals, 8 mm., carry a single row; while in 

 the full-grown specimen the margin is thickly covered with a 

 band of them, one overlapping the other. In the second gnatho- 

 pod the 4th and 5th joints are produced to a strong denticle at 

 the posterior angle. The cvirved finger is longer than the palm, 

 the tip fitting into a groove on the inner side of the hand. The 

 feathered spines on the outer side of the palmar margin are 

 shorter and twice as numerous as those of the inner side, and 

 are set in graduated oblique rows, the longest spine of each row 

 the farthest from the margin ; those of the inner side are also 

 giaduated in size, but set in a continuous line. The curious 

 specialised bristles, characteristic of this family, are to be found 

 on either side of the finger articulation, the dentate one on the 

 outer side, and the plumose on the inner. These bristles are 

 among the first to appear ; in a small specimen, 4 mm., both 

 are well developed. 



Peraiop)ods. Full-grown female. — Agreeing with Sai-s' figures ; 

 sensory armature more complete, as is to be expected. The 2nd 

 peraeopod is longer than the 1st; basal joint wider, the posterior 

 margin densely crowded with sensory spines, as in the gnathopods, 

 that of the 1st with only a single row. In the hinder perseopods, 

 the anterior margins of the basal joints are armed with numerous 

 small spines; the 4th and 5th joints carry a row of small deeply 

 inset spines (fig. 56) on the outer side, in addition to the marginal 

 groups, a double row on the 5th joint of the 5th perseopod. The 

 under surface of some of the joints — 4th of perseopod 3, 4th and 

 5th of perasopod 4, and the 4th, 5th, and 6th of perseopod 5 — is 

 provided with rows of very delicate, mobile, plumose hairs 

 (fig. 57), about 6-8 in a row; a few scattered smaller ones occur 

 on the basal joints. The terminal joints of all the peraeopods are 

 extremely long and slender, the first four with the tip recurved 

 (fig. 62), the fifth with a distinct nail (fig. 63) ; all carry the long, 

 stiff, feathered seta proximally, longest on the 5th. The 1st and 

 5th fingers are subequal to each other in length, the 2nd and 3rd a 

 little longer, the 4th the longest. 



