106 BK1TISH COPEPODA. 



innermost is about twice as long ; the third is the 

 largest, being longer than the whole abdomen. 

 Colour brown. Length ^th of an inch (2 7 mm.). 



The mature form of G. gigas I have taken in Lough 

 Corrib (Ireland), and Lough Skene (Dumfries), and it 

 occurs abundantly in a gathering sent to me by the 

 Rev. H. A. Gratty from a pond at Donnington, near 

 York, and in one from a pond in Lambton Park 

 (Durham), for which I am indebted to the Rev. A. M. 

 Norman. A form which, at one time, I believed to be 

 specifically distinct, I have found abundantly in a 

 great number of localities ; it is characterised by 

 having all the branches of the swimming-feet in the 

 female 2-jointed, while in the male they are 3-jointed ; 

 but as I have never found any females bearing ovi- 

 sacs, as the antennas are only 11 -jointed (this in itself 

 being a character of the last stage of development before 

 attaining maturity), and as the rudimentary (fifth) feet 

 and other organs closely agree with those of G. gigas, 

 I can scarcely doubt that it ought to be referred to 

 that species. The immature form is figured in 

 PI. XX, figs. 11 — 16. I have found it plentifully in 

 many of the lakes of Cumberland, Westmorland, and 

 Northumberland, in the " Broads " of Norfolk and 

 Suffolk, in Lough Skene (Dumfries), and in some 

 ponds in the County of Durham. 



