COPEPODS OP THE WOODS HOLE REGION 



341 



sixth segments longest; second antennae 4-segmented, without an 

 exopod. Rami of first four pairs of legs 3-segmented ; fifth leg en- 

 tirely fused with the fifth metasome segment, represented by a plate 

 armed with three stout plumose setae. A single species. 



ECTOCYCLOPS PHALERATUS (Koch) 

 FiGUKE 203 



Cyclops phaleratus Koch, Deutsclilands Crustaceen, Myriapoden und Arach- 



nideu, p. 21, pi. 9, 1838. 

 Ectocyclops ru'bescens Braby, Proc. Zool. Soc. London, vol. 2, p. 124, pis. 6, 7, 



1904. 

 Platycyclops phaleratus Sars, Crustacea of Norway, vol. 6, p. 78, pi. 48, 1914. 



Occurrence. — Both sexes were obtained in the fresh-water pond on 

 Rams Head Island in Hadley Harbor. 



Distribution. — Europe, Australia (Sars) ; Germany (Koch, van 

 Douwe, Schmeil) ; Turkestan (Ganin, Uljanin) ; Norway (Sars) ; 

 British Isles (Brady, Lubbock, T. 

 Scott) ; Hungary (Daday) ; Russia 

 (Poggenpol, Fischer) ; Sweden (Lill- 

 j eb o r g) ; Bohemia (Fric) ; Croatia 

 (Sostaric) ; Poland (Lande) ; Suri- 

 nam (Chappius) ; Ohio (Turner) ; Illi- 

 nois, Wisconsin, Michigan, Alabama, 

 Manitoba (Forbes); Massachusetts 

 (Cragin). 



Color. — Entire body dark reddish 

 brown, the first free metasome segment 

 lighter with a bluish tinge and almost 

 transparent. The head is also lighter 

 than the rest of the body except at the 

 posterior margin, where the reddish 

 brown forms a dark transverse band. 

 The anal segment, the swimming legs, 

 and the caudal rami are bluish like the 

 second segment; eggs dark blue, almost 

 black; eye reddish, with a yellow spot 

 surrounding it. 



Female. — Metasome elliptical, two-thirds as wide as long; cephalic 

 segment as long as the four following segments ; urosdme half as long 

 as metasome, its segments coarsely denticulated along their posterior 

 margins ventrally and laterally ; genital segment not so long as first 

 two abdominal segments combined; caudal rami less than twice as 

 long as wide, each with three oblique rows of spinules on its dorsal 

 surface and one on the ventral surface. First antennae 10-segmented 

 in most European specimens, but often 11-segmented in America; 



Figure 203. — Ectocyclops phalera- 

 tus: a, Male, first antenna ; 6, 

 male, fifth and sixth legs ; c, 

 female, fifth leg 



