76 A EEVI8I0N' OP THE BEITISH SPECIES OF 



two such spines, the outermost of which is slightly the larger. 

 Pifth foot small, two-jointed, the basal joint short, wide, and 

 bearing one long apical seta; second joint narrower, with two 

 long, almost equal setae. Length 1-4 mm. 



I am indebted to Mr. D. J. Scourfield (after whom I have 

 pleasure in naming it) for specimens of this species taken at 

 "Wanstead Park and in a pond at the Botanic Gardens, Eegent's 

 Park. My first knowledge of the species was, however, derived 

 from specimens which I took myself by moonlight in the surface- 

 net at Coniston, in August, 1883 ; in this gathering it occurred 

 in considerable numbers, as also in a subsequent daylight surface- 

 gathering from the same lake. It occurs also in gatherings 

 made by the Rev. Dr. Norman in Kirk Loch and Castle Loch, 

 Lochmaben, Dumfriesshire, and at Mallow, county Cork. Mr. 

 Scourfield has sent me the following additional list of localities 

 in which he has taken it : Victoria Eegia Tank, Royal Botanic 

 Gardens, Regent's Park ; "Wroxham, Filby and Rollesby Broads, 

 and Heigham Sounds, Norfolk; Higham Park, Woodford. 



There can, I think, be little doubt that this is the species 

 referred to by Sars as Cyclops Leuchartii, — the peculiar build 

 and armature of the swimming feet agreeing with the descrip- 

 tions of that author. Claus, however, does not mention these 

 characters, and as he states that the fifth foot is similar to that 

 of C. brevicornis, it seems impossible that his C. LeucJcartii can 

 be identical with the species now under consideration ; the fifth 

 foot of C. Scour fieldi bears three long and nearly equ^l setse, 

 while that of C. hicuspidatus has two such setse and a short 

 dilated seta or spine. 



The Coniston specimens of C. Scourjieldi are very much less 

 robust than others, more slender in all their parts, and perfectly 

 pellucid except for masses of ingested material in the alimentary 

 tract. An interesting form which must, I think, be looked upon 

 as a variety, has been found by Mr. Scourfield at Higham Park, 

 Essex. Its chief peculiarities are the more nodose anterior an- 

 tennae, — the joints of these appendages being more constricted 

 at their proximal ends, — a slightly different arrangement of the 

 setae of the fifth foot, the two terminal seta? of which spring 



