82 



A EEVISION OF THE BEITISH SPECIES OP 



9. Cyclops viridis, Jurine (PL V., figs. 6-10). 



1820. Monoculus quadricornis viridis, Jurine (3), p. 46, 



pi. III., fig. 1. 

 1851. Cyclops viridts, Fischer (8), p. 412, pi. IX.. figs. 1-11. 



1857. 



1863. 

 1863. 

 1871. 

 1871. 

 1872. 



1875. 

 1878. 

 1880. 



1882. 

 1883. 

 1884. 

 1885. 



Irevicornis, Claus (13), pi. III., figs. 12-17. 

 gigas, idem, ibidem, p. 207, pi. XI., figs. 1-5. 

 viridis and C. gigas, Gr. 0. Sars (20), p. 35. 

 hrevicornis, Lubbock (19), p. 200. 

 Claiisii (junr.), Heller (23), p. 7. 

 Irevicornis, Heller (23), p. 5. 



Pric (24), p. 220, fig. 13. 

 gigas, idem, ibidem, p. 220, fig. 14. 

 Irevicornis, Hoek (29), p. 13, pi. I., figs. 5, 6. 

 gigas, Brady (32), p. 105, pi. XX. 

 viridis, Eehberg (33), p. 540, and C. gigas, 



p. 541. 

 ingens, Herrick (38a), p. 228, pl.lY., figs.1-8. 

 viridis, Cragin (40), p. 3, pi. lY., figs. 8-16. 



,, Herrick (41), p. 145. 



,, Daday (44), p. 214. 



When engaged upon my Eay Society Monograph I was much 

 puzzled to know whether the bulk of my seventeen-]' ointed 

 '' short-horned." specimens — evidently all belonging to the same 

 species — ought to be referred to C. hrevicornis, Claus, or to C. 

 gigas, Claus. It did not occur to me that perhaps the two so- 

 called species might not after all be distinct, as they were both 

 admitted, though apparently with some hesitation, by Gr. O. Sars, 

 But a further acquaintance with the animals, together with the 

 figures and descriptions of various authors, convinces me that 

 there is no sufficient ground for the separation of the two forms. 

 C. gigas appears to be simply a very large variety of C. viridis 

 {hrevicornis). This opinion is held also by Herrick. 



This species is common and widely di,stributed, being noted 

 as occurring in Norway (Gr. 0. Sars) ; Germany (Fischer, Claus, 

 &c.) ; Holland (Hoek) ; Switzerland (Jurine) ; Hungary (Fric), 

 Tyrol (Heller) ; North America (Herrick). In the British 

 Islands it is very common, occurring chiefly in small sheets of 

 water, such as ponds and ditches, but also amongst the vegeta- 

 tion of the margins of lakes. It occurs sometimes also in slightly 

 brackish water — as at Lymington, Hampshii^e ; and I have taken 

 specimens which I cannot distinguish from it by the deep-net in 

 Windermere. 



