DIAPTOMUS. 59 



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

 the female 3-jointed. Eye situated in the median 

 line. 



1. DIAPTOMUS CASTOK, Jurine. PI. VI, figs. 6 13. 



Cyclops cceruleus, O. F. Miiller. Entomostraca, p. 102, t. xv, 

 figs. 1-9 (1785). 



lacinulatus ( ? ), Miiller. Ibid., p. 105, t. xvi, figs. 46 



(1785). 



rubens ($), Miiller. Ibid., p. 104 t. xvi, figs. 13 (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 aj (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. 110, t. xiv, figs. 14 (1863). 

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



p. 197, pi. xxxi, figs. 711 (1853). 



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 llth with spines of a 

 similar kind though smaller; the hinge is situated 



