188 COPEPODA. 



1892. Cyclops fuscus, Schmeil, I. p. 123, pi. i. figs. 1-7 b ; pi. iv. 



fig. 16. 

 1901. Cyclops fuscus, Lilljeborg, p. 44, pi. iii. figs. 12-15. 



The River Otter and Clapton Lea, Devon. 



Antennules composed of 1G joints. 

 CYCLOPS LAXGUIDUS, G. 0. Sars. 



1862. Cyclops languidus, G. O. Sars, Oversigt af de indenlandsl\e 



Ferskvandscopepoder, p. 40 (separate copy). 

 1892. Cyclops languidus, Schmeil, I. p. 8'1, pi. iii. figs. 9-17. 

 1901. Cyclops languidus, Lilljeborg, p. 59, pi. iv. tigs. 8, 9. 



The only gathering where this species was observed was 

 from some marshy ground on Exinoor about 1450 feet above 

 sea-level, May 13th, 1904. 



Antennules composed of 12 joints. 

 CYCLOPS SERRULATUS, Fischer. 



1851. Cyclops serrulatus, Fischer, "Beitr. z. Kennt. St. Petersburg 

 Cyclopiden," Bull. Soc. Imp. des Nat. Moscou, vol. xxiv. p. 423, 

 pi. x. tigs. 22, 23*, 26-31. 



The form generally regarded by British carcinologists as 

 Fischer's Cyclops serrulatus occurred in most of the fresh- 

 water gatherings collected throughout Devon and Cornwall. 



It is probable, as Prof. Lilljeborg has recently shown *, 

 that more than one species may be included here under the 

 name of Cyclops serrulatus ; and one of the forms described 

 by that author as Cyclops varius seems to be distinguished 

 chiefly from typical C. serrulatus by the margin of the last 

 joint of the antennules being hyaline, smooth, and without 

 either cilia or striations f; whereas in C. serrulatus the margin 

 of this joint bears a fringe of minute cilia more or less 

 throughout its entire length. Three varieties of C. varius 

 are described by Lilljeborg, viz. sp^i-atus, proximus, and 

 bracliyurus. 



A form which we think undoubtedly represents the variety 

 Iracliyurus is frequent in a number of the Devon and Corn- 

 wall gatherings. It is readily distinguished by the rather short 

 and stout f urcal joints. The variety referred to as a mountain 

 form in the Monograph of British Copepoda by Prof. G. S. 

 Brady (vol. i. p. 100), and represented by figure 7, plate xxii., 



* Pp. 81-91 (1901). 



t "Antennae articulis 12 composite. Margo posterior articul- 



oium eorum ultimorum limbo hyalino Isevi et sine aculeis vel striis." 



