55 



occurring about in the middle. Cephalic segment comparatively large and evenly 

 rounded in front. Last trunk-segment somewhat produced laterally. Tail only 

 slightly exceeding half the length of the anterior division; genital segment con- 

 spicuously dilated in front and gradually narrowed behind. Caudal rami about 

 the length of the last 2 segments combined and scarcely divergent ; seta of outer 

 edge somewhat remote from the apex, middle apical setae rather slender, the inner 

 one considerably longer than the outer, and about equalling in length the tail 

 and last trunk-segment combined; seta of inner corner very thin, though consider- 

 ably longer than that of the outer. Anterior antennae comparatively short, not 

 attaining the length of the cephalic segment, and only composed of 12 joints. 

 Posterior antennae with the last joint scarcely longer than the penultimate one. 

 Anterior maxillipeds short and stout, with the claw of the 2nd basal joint almost 

 straight. Natatory legs with both rami in all the pairs biarticulate, 4th pair, in 

 the living animal, generally projecting to each side of the trunk; inner ramus 

 of this pair with both apical spines well developed, the outer one about half 

 as long as the inner. Last pair of legs with the proximal joint wholly confluent 

 with the segment, its seta springing off from the lateral corner, distal joint small, 

 narrow conical in form, and having an extremely minute spinula in the middle 

 of the inner edge, apical seta rather slender. Ovisacs comparatively large, oblong 

 in form, and somewhat divergent. Seminal receptacle small, rounded, exserted on 

 each side to a narrow band-like stripe. 



Colour whitish, with a fainte yellow or reddish tinge. 



Length of adult female 0.70 0.90 mm. 



Remarks. This species, together with the succeeding one, is included by 

 Dr. Schmeil in a particular group of Cyclopses (his varicans-bicolor group), chiefly 

 characterised by the biarticulate rami on all the natatory legs, and the imperfect 

 development of the last pair of legs. The same characters are also exhibited by 

 some exotic Cyclopses. Thus, of the several species described by the present 

 author from the lake Tanganyika, Central Africa, C. attenuatus, C. Cunningtoni 

 and C. pachycomus belong to this group. The same is also the case with the 

 Australian species, C. Arnaudi, G. 0. Sars. Finally the form recorded by Dr. 

 Lepeschkin as C. diaphanus, var. dengizica represents another species of the said 

 group. According to the statement of Dr. Schmeil the C. orientalis of Uljanin is 

 identical with the present species, and I am also of opinion, that the C. rubellus 

 of Lilljeborg can hardly be distinguished specifically. 



Occurrence. This form seems to be of rare occurence in our country. 

 I have only met with it in some grassy ponds near Christiania. The specific 

 name varicans alludes to the peculiar manner in which the 4th pair of natatory 



