146 BRITISH COPEPODA. 
toot the outer branch is converted into a stout clasping 
organ, which is bent across the inner branch, and had 
its last joint armed with several strong spines. Ovisac 
single. 
1. Harpacticus CHELIFER (Muller). Pl. LXV, figs. 
1—15; and Pl. LXIV, 
fies. 19, 20. 
(Not Harpacticus chelifer, Lilljeborg.) 
Cyclops chelifer, O. F. Muller. Zool. Dan. Prodr., 2418; Hnto- 
mostraca, p. 114, taf. xix, figs. 1—3 (1776). 
Nauplius — Philippi. Weigmann’s Archiv, p. 69 (1843). 
Arpacticus — Baird. Brit. Entomostraca, p. 212, t. xxix, 
figs. 2, 3, 3 a—g (1850). 
Harpacticus — Claus. Die frei-lebenden Copepoden, p. 135, 
t. xix, figs. 12—19 (1863). 
— — Boeck. Oversigt Norges Copep., p. 37 (1864). 
P gracilis, Claus. Loc. cit., p. 135, taf. xix, fig. 20. 
P — elongatus, Boeck. Oversigt Norges Copep., p. 38 
(1864). 
Body elongated, slender, cylindrical, rostrum rather 
long and curved, reaching beyond the first joint of 
the anterior antenna. Anterior antenne (Pl. LXV, 
fio. 2) elongated, slender, 9-joimted, third and fourth 
joints longer than the first two, fifth joimt short, 
sixth nearly twice as long, last three very small. 
Anterior antenna of the male hinged between the 
fourth and fifth joints, the next two joints forming a 
corrugated vesiculiform swelling, and terminating in a 
crooked, claw-like appendage. Inner joint of the 
posterior antenna (fig. 4) 2-jointed. Mandibles (fig. 5) 
broad and strong, basal joimt of the palp large, and 
giving attachment to two slender and nearly equal 
