REPORT ON THE AMPHIPODA. 659 



of the hand have flexible ends. The minute finger ends in a kind of double nail, some 

 minute teeth occupying the inner margin of the outer and longer division, the nail 

 proper, which curves over towards the palm in the usual manner, while the smaller 

 division, perhaps only a projection of the finger-margin, curves away from the palm ; at 

 the origin of the two is a lono- cilium. 



First Peneojwds. — Side-plates scarcely as large as those of preceding segment ; 

 branchial vesicle like that of the preceding limb, and both there and here attended by a 

 very small oval plate, quite smooth, which seems to be an accessory vesicle ; first joint 

 of leg much shorter than in the two preceding pairs ; third joint longer than fourth, 

 subequal to fifth, bowed forwards ; fourth joint slender, parallel-sided, four small spines 

 on the back rim, the two longer ones faintly geniculate ; the fifth joint much dilated 

 distally, presenting a sort of palm with two strong teeth pointing towards the finger- 

 hinge and beset with strong spines, a single and two pairs ; these spines are straight, 

 with tiny curved tips pointing in the same direction as the teeth on the palm, and 

 with accessory threads springing from about the centre. The finger is powerful, about 

 as long as the fourth joint, much curved, smooth edged, sharply pointed. 



Second Perwopods. — Side-plates larger than the preceding three combined, narrow at 

 the base, projecting far forward so as to cover a considerable piece of both the preceding 

 side-plates, largely excavated behind for the great side-plate of the fifth segment ; branchial 

 vesicles like those already described ; first joint of leg considerably longer than in the 

 preceding pair, to which this pair is in other respects similar, except that the third, fourth 

 and fifth joints, and especially the fourth, are more elongate. 



Tliird Perieo2wds. — Side-plates very large, as broad as those of the fourth segment, 

 and at the base very much broader, front lobe incised below, not much deeper than the 

 hinder part, which has its lower margin straight ; branchial vesicle with small accessory 

 plate as in preceding segments ; first joint inserted by a bent neck within the incised 

 lobe of the side-plate, seven short spines along the front margin, the hinder part 

 produced almost as far as the three following joints, the hind margin divided into eight 

 very pronounced, sharp, downward-j^ointed teeth, and the inner margin of the process 

 divided into seven of similar character, the apex of the process forming a sharp terminal 

 tooth considerably larger than any of the lateral dentations. The second joint is small ; 

 the third, spined on both edges, longer than the fourth, but shorter than the fifth ; the 

 fourth spined in front, and slightly behind ; the fifth similar in structure to the corre- 

 sponding somewhat smaller joint of the preceding pair, with three pairs of spines at the 

 palm ; finger as in the preceding pair, not larger. The remarkable decurrent processes 

 of the first joint do not show an absolute uniformity in the marginal incisures between 

 the two members of the pair of limbs, a point deserving of attention in view of the 

 manufacture of species based upon minute difl^erences. 



Fourth PersBOiJods. — Side-plates rather large, a little deeper behind than in front ; 



