REPORT ON THE AMPHIPODA. 1351 



Phronima atlantica, Guerin (PI. CLX.). 



1836. Phronima atlantica, Guerin, Mag. Zool., vi. CI. vii. p. 7, pi. xviii. fig. 1. 



1836. „ „ Guerin-Meneville, Icon, du rogne anim., Crust., pi. xxv. fig. 4. 



1840. „ „ Milne-Edwards, Hist. Nat. des Crust, t. iii. p. 93. 



1852. : , „ Dana, U.S. Explor. Exped., vol. xiii. pt. ii. p. 1001. 



1862. „ „ Spence Bate, Brit. Mus. Catal. Arupk. Crust., p. 318, pL li. fig. 4. 



1882. „ „ Streets, Proc. U.S. Nat. Mus., p. 5, pi. i. figs. 1, la, 2. 



Last segment of the peraeon elongate, a little longer than the first of the pleon, which 

 is much longer than either of the two following ; the first three segments of the pleon 

 with the postero-lateral angles produced in the female, the tooth being longer in the 

 second than in the first, and in the third than in the second segment ; in the male 

 specimen only the third segment had a tooth and that a small one. 



First and Second Pereeopods with the hind margin of the first and second joints 

 apically produced to form an acute slender tooth. In the male this tooth seems to be 

 unimportant in size. 



Third Perwopods. — First joint very little expanded below, each margin having a 

 pointed apex ; the second joint having the front margin produced into a pointed apex, 

 this joint being as long as the third in the male specimen, but much shorter in the female; 

 the third joint little dUated ; the fourth considerably longer in the female than the distal 

 breadth, the front margin forming only a small apical tooth, separated by an almost 

 semicircular cavity from a much smaller tooth which projects from the palmar margin 

 almost as far as the front tooth ; a second much smaller cavity reaches the centre of the 

 palm, the margin of which beyond this cavity is at first either crenate or cut into two or 

 three little teeth ; in the male this joint differs only in being a little broader near the 

 base and shorter in proportion to the breadth ; the fifth joint is much bent, almost as 

 long as the fourth, with a slight bulge near the centre of the inner or front margin, the 

 bulge being nearer the apex in the male than it is in the female ; the finger as usual 

 minute. 



Fourth Pereeopods. — Branchial vesicles not quite so long as the first joint. The first 

 joint with the two lines of gland-cells very distinct, each line divided into four elongate 

 packets ; the front margin of the joint apically produced into a narrow acute tooth, less 

 developed in the male than in the female; front margin of the second joint produced into 

 a projecting tooth. 



Fifth Perseopods simdar to the fourth, with the usual differences in the pro- 

 portions. 



Pleopods. — Peduncles elongate, the inner ramus with seven, the outer with eight 

 joints ; the first joint in each ramus nearly as long as the rest together. 



Uropods in agreement with those of Phronima pacifica, Streets, except that in the 

 female the inner ramus of the second pair is much more than half the length of the outer, 



