DIAPTOMUS. 59 



branch much the smaller. Abdomen of the male 5-, of 

 the female 3-jointed. Eye situated in the median 

 line. 



1. Diaptomus Castor, Jurine. PI. VI, figs. 6 — 13. 



Cyclops cceruleus, O. F. Miillei*. Entomostraca, p. 102, t. xv, 

 figs. 1—9 (1785). 



— lacinulatus ( $ ), Miiller. Ibid., p. 105, t. xvi, figs. 4 — 6 



(1785). 



— rubens ($), Miiller. Ibid., p. 104. t. xvi, figs. 1—3 (1785). 

 Monoculus Castor, Jurine. Histoire des Monocles que se trouvent 



aux Environs de Geneve, p. 50, tabs. 4 — 6, 



(1820). 

 Cyclopsina -^ M. Edwards. Nat. Hist. Crust., vol. iii, 427 



(1840). 

 Diaptomus Castor, Westwood. Partington's Cyclopaedia, art. 



"Cyclops "(1836). 



— — Baird. Nat. Hist. Brit. Entom., p. 219, 



tab. xxvi, figs. 1, 2, 2 a—j (1850). 



— — Claus. Die freil-ebenden Copep., p. 201, 



t. xxxv, figs. 15 and 16 (1863). 



— — Lilljeborg. De Crust, ex. ord. trib., t. xii, fig. 



10, t.xiii,figs. 1—10, t. xiv, figs. 1—4 (1803). n5~~ 



— — Lubbock. Trans. Linn. Soc. Lond., vol. xxiv, 



p. 197, pi. xxxi, figs. 7—11 (18^3). £ 



— Westwoodii, Lubbock. Loc. cit., pi. xxxi, figs. 1 — 6. 



— Castor, Fric. Die Krustenthiere Bohmens, p. 225, fig. 22 



(1871). 



Anterior antenna (fig. 8) 25-jointed ; gradually 

 tapering from the base and beset with setse of mode- 

 rate length, one or two on each segment, except on 

 the terminal one, which has five at its extremity ; right 

 antenna of male (fig. 7) provided with a hinge- joint, 

 above which for the length of six segments it is much 

 swollen ; the 13th joint is armed with a strong mar- 

 ginal spine, and the 10th and 11th with spines of a 

 similar kind though smaller ; the hinge is situated 



