160 BEITISH COPEPODA. 



lidium they differ very remarkably in the structure of 

 the mouth-organs and the first pair of swimming- feet, 

 as well as in the minor characters of other parts. 

 Altogether, indeed, these organs are much nearer in 

 structure to those of the typical Harpacticidce than 

 are those of the immediately preceding genera. 



1. PELTIDIUM DEPRESSUM (Baird). PI. LXXII, figs. 1 5. 



Alteutha depressa, Baird. Trans. Berwick Nat. Club, ii, p. 155 

 (1845); Nat. Hist. Brit. Entom., p. 216, 

 tab. xxx, figs. 1, 2 (1850). 

 Carillus dblongus, Goodsir. Ann. and Mag. Nat. Hist., vol. xvi, 



pi. xi, fig. 12 (1845). 

 Peltidium purpureum, White. Popular History of British Cru- 



tacea, p. 308, pi. xviii, fig. 4 (1857). 

 ? Philippi. "Weigmann's Archiv, p. 131, 



taf. iv, figs. 12, 13 (1839). 



Alteutha purpurocincta, Norman Brit. Assoc. Report, p. 298 

 (1868). 



Body ovate ; first segment nearly one half the length 

 of the body; rostrum large, broad, and prominent; 

 second joint of the anterior antenna (in the female) 

 longest ; first, third, and fourth nearly equal to each 

 other, and about two thirds the length of the second ; 

 last five joints very small, all rather densely setose 

 (fig. 2). Second foot-jaw (fig. 3) 3-jointed; hand 

 ovate, shortly setose on the inner margin. Fifth foot 

 not spinous on the sides, but armed at the truncate 

 apex with three strong spines, the innermost of which 

 is the longest (fig. 4). Caudal lamellse nearly twice as 

 long as broad, not tapered to the apex, bearing four 

 terminal spines, the innermost the longest, the outer- 



