FRESII-WATEB CTCL0PID.2E AND CALAXID.K. 19 



C. serrulatus is, in the British Islands, certainly the commonest 

 representative of the genus, few gatherings of Copepoda, from 

 whatever elevation, whether from lakes, ponds, or smaller col- 

 lections of water, being entirely without it. It is, moreover, 

 remarkably constant in its characters and can scarcely be con- 

 founded with any other species. The American C. pectinifer, 

 Cragin, seems to be only a variety and scarcely a well-marked 

 one. Eehberg identifies this species with C. agilis, Koch, chiefly 

 on account of the shape of the egg-sacs. Koch's figures may 

 very probably be meant to refer to C. serrulatus, but it seems 

 scarcely wise to discard Fischer's well-known specific name for 

 one of only speculative propriety. 



C. serrulatus is recorded by almost all continental authors : — 

 Norway (G. 0. Sars) ; Sweden (Lilljeborg) ; Germany (Fischer, 

 Koch, Claus) ; Tyrol (Heller) ; Bohemia (Fric) ; Holland (Hoek) ; 

 Turkestan (Uljanin), North America (Herrick). 



12. Cyclops macrurus, G. 0. Sars (PL YIL, fig. 2). 



1863. Cyclops macrurus, G. 0. Sars (20), p. 45. 

 1878. „ „ Brady (32), p. Ill, pi. XXIV., 



figs. 1-5. 



Crag Lake, Northumberland, was until recently the only- 

 known British locality for this species. But it occurs also very 

 plentifully in collections made by the Bev. Dr. Norman in the 

 Castle Loch, Lochmaben, Dumfriesshire, and in Loch Achray, 

 Perthshire. It is recorded by G. 0. Sars from Norway and by 

 Behberg from Germany. The last-named author identifies it 

 with C. spinulosus, Claus, but as that species is described as 

 having antennas longer than those of C. serrulatus it is impossible 

 to accept the identification. 



13. Cyclops magnoctavus, Cragin. 



1883. Cyclops magnoctavus, Cragin (40), p. 5, pi. III., 



figs. 14-23. 



Cephalothorax subelliptical, widest in the middle, none of its 

 segments angulated nor prominent laterally, the last segment 



84 



