FRESH-WATER CTCLOPIDJE AND CALANIDJS. 13 



The most noteworthy characters of C. vicinus are to be found 

 in the shape of the thoracic segments, the short anterior antennae, 

 the serrated margins of the abdominal segments, the proportions 

 of the caudal rami and setae, and the form of the fifth foot. 



The British localities already published are Bolam Lake and 

 Paston Tarn (Northumberland), and Tresco (Scilly Islands). I 

 have now to add the following localities, where it has been found 

 by Mr. D. J. Scourfield : "Wanstead Park, Essex ; Tottenham ; 

 Dulwich; Leytonstones; Eagle Pond, Snaresbook; Royal Botanic 

 Gardens, Regent's Park ; Pinner, Middlesex ; Highani Park, 

 Woodford. In Dr. Norman's gatherings it occurs as follows : — 

 Loch Achray; Loch Katrine, Loch Leven, Kinross; pools near 

 Sprinkling Tarn, and Ennerdale Water, Cumberland ; Broomley 

 Lough and Eallowlees Lough, Northumberland. 



7. Cyclops bicuspidatus, Claus (PI. V., figs. 1-5). 



1857. Cyclops bicuspidatus, Claus (14), p. 209, pi. XI., figs.6,7. 



1863. ,, „ Claus (18), p. 101. 



1863. ? „ „ G-. 0. Sars (20), p. 38. 



1876. „ „ Hoek(29), p. 17, pi. I., figs. 7-11. 



1880. ,. bisetosus, Rehberg (33), p. 543. 



Female. — The body is long and slender, gradually tapering 

 from the front backwards, and without any distinct constriction 

 between thorax and abdomen. The first body-segment is about 

 equal in length to the three following segments and has its 

 posterior angles rounded off ; second segment produced laterally, 

 its posterior angles forming sharp angular projections ; third seg- 

 ment narrower and also having sharply produced posterior angles ; 

 lateral margins of the fourth segment rounded and showing no 

 posterior angles ; last thoracic segment very short, scarcely more 

 than one-half the length of the preceding segment, its posterior 

 angles sharp ; all the segments are sharply separated one from 

 another, being much constricted in front. The first abdominal 

 segment is large, tumid in front and narrowed behind, nearly 

 equal in length to the following three segments. Caudal rami 

 long, closely approximated and parallel, about five times as long 

 as broad, their inner margins destitute of hairs : the two median 

 terminal setse are long and very feebly ciliated, the innermost 



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