REPORT ON THE AMPHIPODA. 963 



near it, a little decurrent behind, with spines on both margins, none of them strong ; 

 the fourth joint with four groups of spines on each margin ; the fifth joint considerably 

 longer than the third or fourth, with numerous spines on both margins, especially on the 

 front ; the finger very long and thin, longer than the third or fourth, subequal to 

 the fifth joint, with a dorsal cilium and two dorsal setules, as in the preceding 

 perseopods ; which in all but the first joint it nearly resembles, but having the fifth 

 and sixth joints much longer. 



Fourth Perseopods. — Side-plates with the hinder lobe much larger than the front one. 

 Branchial vesicles small, expanded below on either side of the narrow upper part. The 

 limb nearly as in the preceding pair, rather longer in respect of the first and third joints, 

 the first joint being a little more expanded above than below, while in the third perseo- 

 pods the reverse is the case. 



Fifth Perseopods, — Side-plates not bilobed, much deeper behind than in front. 

 Branchial vesicles small. Limb similar to that in the two preceding pairs ; first joint 

 produced a little upwards in front, and considerably downwards behind, broader above 

 than below ; the third joint not longer than the fourth. 



Pleopods. — The peduncles have a row of about a dozen setse near the outer margin, 

 and two groups near the top of the inner, and some also on the lower margin. The two 

 coupling spines are very small and crooked, with only one lateral retroverted tooth, which 

 is placed a long way below the terminal hook ; there is a setule or small simple spine 

 close by ; the cleft spines appear to be six in number on the first and second, and five on 

 the third pleopods, with an uncleft plumose seta above ; the joints number twenty on the 

 inner ramus to twenty-three on the outer. 



Uropods. — The peduncles of the first pair longer than the rami ; the rami stiliform, 

 the inner somewhat longer than the outer, peduncles and rami bordered on the upper 

 or inner margins with numerous spiues and having their edges finely pectinate ; the 

 peduncles of the second pair equal in length to the inner ramus, which is broader and 

 longer than the outer and more closely set with spines; peduncles and rami all fringed with 

 spines and pectinate ; peduncles of the third pair subequal in length to the outer ramus ; 

 rami broad, lanceolate, rather strongly serrate on the inner edges, the inner broader 

 and considerably longer than the outer, with some plumose setse besides its numerous 

 spines ; the peduncles with few spines, the rami with many, the edges of all pectinate. 



Telson elongate, tapering, extending beyond the peduncles of the third uropods 

 almost to the end of the rami, cleft for more than three-quarters of its length, not 

 dehiscent, apices acute, all the margins except the basal finely pectinate, a couple of cilia 

 not far from the base and outer margin on either side, and some others at other points, 

 but scarcely perceptible even with a high power. 



Length. — The specimen, in the position figured, measured, without the antennse, two- 

 fifths of an inch. 



