REPORT ON THE AMPHIPODA. 1005 



Third Perasojiods. — Within the large bilobed side-plates, just above the attachment 

 of the first joint, there is a very narrow, curved, round-ended process. The first joint 

 widest near the middle, about two and a half times as long as broad, the front margin 

 almost straight, shallowly serrate with a minute setulc in each indent, the apex produced 

 into a small tooth, the hind margin convex, carrying small setules, very shallowly serrate 

 below the centre ; the second joint with spinules along the front margin ; the third joint 

 much longer than the fourth ; the fifth a little longer than the third, having a few 

 spinules along the hind margin, and like the two preceding joints several along the front ; 

 the finger slender, nearly straight, little more than a fifth of the length of the fifth joint. 



Fourth Perseopods. — Branchial vesicles much shorter than the first joint, the upper 

 part much produced behind. The first joint with the greatest breadth near the base, 

 longer and broader than in the preceding pair, considerably longer than all the remaining 

 joints together, the front margin rather sinuous, a little serrate below and produced into 

 a small tooth, the hind margin convex, rising much above and descending much below 

 the front, the lower part shallowly serrate, the produced triangular apex reaching con- 

 siderably below the second joint ; the second joint short, its front margin straight, with 

 an apical tooth, behind which is a second much longer tooth ; the third joint as long as 

 the three following joints together, pectinate with strong outstanding teeth along the 

 front margin, and smaller teeth about the apices, of which the front one is a little more 

 produced than the hind one ; a spine projects a little above the front apex in this and 

 the next joint ; the fourth joint narrower than the third, shorter than the fifth, with 

 varied pectination of the front and apical margins ; the fifth joint very little curved, the 

 pectination varied, decurrent ; the finger not a third of the length of the fifth joint. 



Fifth Perwopods. — The first joint nearly as broad as in the third pair, but much 

 shorter, the muscles occupying a very small portion of the expanse ; the second joint a 

 little longer than broad ; the third joint as long as the two following together, narrow 

 and narrowing distally ; the fourth straight, subequal in length to the fifth ; the fifth 

 apically narrowed ; the finger not a quarter of the length of the fifth joint. 



Pleopods. — Peduncles large and powerful. The coupling spines short, round- 

 headed, with retroverted points ; the cleft spine with short nearly equal arms, of which 

 the shorter is a little apically dilated and appears to form a hook, whde the longer arm 

 is greatly but unsymmetrically dilated ; the joints of the rami number from twelve to 

 fourteen, the first joint of each ramus being long, with several setae. 



Uropods. — Peduncles of the first pair about as long as the coalesced fifth and sixth 

 segments of the pleon, longer than the rami, which are elongate, the outer shorter than 

 the inner, both with denticulate margins, the inner margin being more strongly toothed 

 than the outer ; peduncles of the second pair shorter than the rami, which are 

 respectively as long as those of the first pair, with the inner margins much less strongly 

 denticulate ; the peduncles of the third pair very little shorter than the outer ramus, 



