104 BRITISH COPEPODA. 



3. CYCLOPS STRENUUS, Fischer. PL XIX, figs. 1 7. 



Monoculus quadricornis rubens, Jurine. Hist, des Monocles, p. 1, 



pi. i, and pi. ii, figs. 19 (1820). 



Cyclops pictus, Koch. Deutschlands Crust., H. xxi, tab. i (fide 

 Sars) (1841). 



strenuus, Fischer. Bulletin de la Soc. Imp. des Nat. de 



Moscow, torn, xxiv, p. 419, tab. ix, 

 figs. 1221 (1851). 



Sars. Oversigt Ferskvandscopepoder, p. 27 



(1863). 



quadricornis, Lilljeborg. De crust, ex. ord. trib., p. 150, 



t. xiv, figs. 5,6; t. xv, figs. 1 11 ; and 

 t. xxvi, fig. 19 (1853). 



brevicaudatus, Glaus. Das Genus Cyclops, p. 34, t. ii, 



fig. 12; Die frei-lebenden Copepoden, 

 p. 100 (1857). 



Fric. Die Krustenthiere Bohinens, p. 221, 

 fig. 15 (1871). 



Anterior antennae (fig. 1) reaching about to the 

 fourth thoracic segment, only slightly tapering 

 towards the apex ; last three joints much less slender 

 than in the foregoing species ; joints of the posterior 

 antennaB short and stout. Joints of the swimming 

 feet destitute of cilia at the margins. Fifth foot 

 (fig. 6) composed of two joints, the first having a 

 moderately long apical seta, the second one very long 

 seta at the extremity, and a spine-like seta on the 

 inner margin. Caudal segments slender (fig. 7), 

 about three times as long as the last abdominal seg- 

 ment. Of the four caudal setae, the outer is the 

 shortest and only about half as long as the caudal 

 segments ; all the setee are finely plumose ; the 

 third seta is the longest, and about once and a half 



