REPORT ON THE AMPHIPODA. 917 



ceding pair, excavate behind but not far down. The limb and its appendages not 

 materially different from the preceding pair. 



Third Perzeopods. — Side-plates broader than deep, the hind lobe deeper than the 

 front one. Branchial vesicles much larger than the first joint. Marsupial plates small. 

 First joint tending to oval in form, broader above than below, with setas on the upper part 

 of the front margin, succeeded by several groups of spines, the more convex hind margin 

 very slightly serrate and scarcely armed ; the second joint short, with two groups of 

 spines in front, partly overlapped behind by the lower lobe of the first joint ; the third 

 joint like that of the preceding perseopods, but rather larger ; the fourth and fifth joints 

 likewise resembling those of the preceding pair, but being rather wider ; the finger 

 similar. 



Fourth Perseopods. — Side-plates with a downward-produced hind lobe. Branchial 

 vesicles broad but not descending quite to the lower end of the first joint, with an 

 accessory pocket quite at the base. The limb resembling that of the preceding pair, but 

 with the joints longer, except perhaps the second and the finger. 



Fifth Perseopods. — Side-plates as usual small, deeper behind than in front. Branchial 

 vesicles broad, but short, not reaching the middle of the first joint. The first joint broader 

 and longer than in the preceding pair ; the second and third joints similar, but the 

 spines on the front margin of the third differently grouped. 



Pleopods. — The peduncles produced on one side into an irregular tongue-like process 

 beside the first joint of the outer ramus ; the coupling spines slender, with three or four 

 denticles ; the cleft spines in the adult numbering six on the first pair, five on the third ; 

 in the young there appear to be but four on the third pair ; the joints of the rami 

 numbering fifteen or sixteen in the young, twenty-five or twenty-six in the adult. 



Uropods. — Peduncles of the first pair longer than the rami ; outer ramus shorter 

 than the inner, both spined along the edges and tipped with spines ; peduncles of the 

 second pair shorter than the longer inner ramus ; the rami armed as in the preceding 

 pair, which they much resemble, carrying many more spines in the adult than in the 

 young specimens ; peduncles of the third pair much shorter than the rami, reaching back 

 beyond those of the second, and just level with those of the first pair ; the rami long, 

 broad, lanceolate, acute, fringed on the margins with numerous spines and setae, the outer 

 scarcely shorter than the inner, reaching back just as far as the inner ramus of the first 

 pair. 



Telson much longer than the peduncles of the first uropods, cleft beyond the centre, 

 tapering, not dehiscent, with a small emargination carrying a spine on the side just above 

 each apex, or it may be said that each apex is emarginate, with the outer horn of the 

 emargination shorter than the inner. 



Length. — One of the specimens, in a very slightly curved position, measured three- 

 fifths of an inch, exclusively of the antennas ; this was an adult female. 



