AMPHIPODA. 289 



Lower antennae: 1st joint about hail' as long as the 2nd. which is rat her longer 

 than tiic .">nl ; flagellum 6-jointed, subequa] to the Last 2 peduncular joints. Both 

 pairs arc similarly fringed below with long curved seta'. 



Mandibles small, shorter than the 2nd joint of the palp; cutting edge double; 

 molar tubercle rather large, but not prominent, palp projecting to the middle of the 

 2nd joint of the lower antennae ; 1st joint very small, 2nd and 3rd subequa] 

 (fig. 50. m.). 



Maxillipeds : inner plate reaching the end of the 1st joint of the palp, spinous on 

 the angle : outer narrow, reaching the middle of the 2nd joint, with slender curved 

 spines near the top ; 1st and 3rd joints of palp subequal ; 2nd about twice as long; 

 4th rather more than half as long as the 3rd, the apex rounded and setose. 



First gnathopods : side-plates small, front angle acute, with a setule on the point ; 

 1st joint subequa] to the wrist, curved; wrist subequal to the hand in length and 

 width, the hind margin setose ; hind margin of the hand convex and setose, the palm 

 undefined. Dactylus half as long as the hind margin (fig. 50. gn. 1 ). 



Second gnathopods : side-plates as in the 1st, but smaller ; 1st joint stout, sub- 

 equal to the next 3 ; wrist subequal in width to the hand, along the anterior margin 

 of which it is carried for about one-third of its length. Hand longer than the wrist, 

 subquadrate, the palm almost rectangular to the hind margin, convex, and defined by 

 a strong tooth, behind which is a notch which receives the point of the dactylus 

 (fig. 50. gn.-). 



First and 2nd peraeopods are rather longer than the 2nd gnathopods and strongly 

 built ; the side-plates alike small and triangular, the angles rounded. The 1st joint 

 is subequal to the next 3, about twice as wide as the 3rd joint, and widening distally ; 

 the front margin distally convex in the 1st pair and straight in the 2nd; the 3rd 

 joint as long as the 2nd, 4th, and 5th together, and twice as wide as the last 2. 

 Dactylus short (fig. 50. pp. 2 ). 



Third perseopods hardly reaching the end of the 1st joint of the 2nd pair ; 1 st joint 

 almost as wide as long, the front margin very convex ; the 2nd subequal to the 4th 

 and the 3rd to the 5th, which is the narrowest; the 3rd and 4th are obcordate. 

 Dactylus reversed, with a secondary tooth on the outer side (fig. 50. pp. 3 ). 



Fourth peraeopods like the 3rd, but longer. 



Fifth peraeopods rather longer than the 4th; the 1st joint with the hind margin 

 almost straight and ending in a rounded right angle ; otherwise as in the preceding 

 pairs (fig. 50. pp. 5 ). 



The last 3 pairs of peraeopods are feeble, the last pair hardly reaching the 3rd pleon 

 segment, and neither as long or strong as the first 2 pairs of peraeopods; they are 

 almost devoid of spines or seta;. 



First uropods : peduncle rather shorter than the upper ramus, which is styliforn. 

 curved and spinulous on the proximal half of the inner margin ; the lower ramus is 

 about one-fourth shorter than the upper, obliquely truncate at the end, where there 



