COPEPODS OF THE WOODS HOLE REGION 337 



Distribution. — Germany (Koch, Schmeil) ; Sweden (Lilljeborg) ; 

 France (Richard) ; Poland (Lande) ; Norway (Sars) ; North America 

 (Herrick). 



Color. — Body dark blue, somewhat tinged with brown ; the anterior 

 portion of the cephalic segment and sometimes the whole segment is 

 lighter than the rest oi the body ; eggs brown ; eye reddish. 



Female. — Metasome broadly oval, breadth somewhat more than 

 half the length; urosome slender, one-third as long as the metasome; 

 genital segment as long as the three abdominal 

 segments combined. No hyaline membrane visible 

 on the first antennae; second and third segments 

 of second antennae equal in length, fourth seg- 

 ment one-fourth longer. Basal segment of fifth 

 leg ciliate on its inner margin, distal segment as 

 wide and as long as the basal segment, with a 

 minute spine on each lateral margin closely proxi- figure 2ou.~j/acro- 



1 , ;i 1 1 i. 1 • r^ • 1 cyclops histriatus: 



mal to the regular lateral spine. Ovisacs only Female fifth leg 

 slightly divergent; semen receptacle elongate, 

 its posterior portion tongue-shaped, with a median posterior fissure 

 extending beyond the center. Total length, 1.5-2.25 mm. 



Male. — Unknown . 



Remarks. — Marsh made this species a synonym of what he desig- 

 nated as Cyclops albidus Jurine, but Schmeil and Sars have regarded 

 it as a distinct species, and it seems as well founded as any of the 

 others. It may be distinguished by the fact that the second and 

 third segments of the second antennae are equal and the fourth seg- 

 ment is longer than either of them, the end segment of the first 

 antennae has no hyaline membrane, and the fifth leg has minute 

 secondary spines. 



Genus EUCYCLOPS Claus, 1893 



Body slender, the two divisions sharply defined ; metasome obovate, 

 the epimeral plates well defined and prominent; fifth segment pro- 

 duced on either side into a hairy lobe, overlapping the base of the 

 genital segment ; urosome slender ; genital segment swollen anteriorly, 

 narrowed posteriorly; caudal rami elongate and finely or coarsely 

 denticulate or smooth on their outer margins. First antennae 12-seg- 

 mented; second, third, and fourth segments of second antennae equal 

 in length. Rami of first four pairs of legs 3-segmented; fifth, legs 

 very small, 1-segmented ; trilobed at their tips, the inner lobe armed 

 with a denticulate spine ; each of the other two lobes with a filiform 

 seta. 



