54 



and nearly equalling the tail in length; seta of inner corner very small, that of 

 the outer about twice as long and spimform. Anterior antennae short and stout, 

 not nearly attaining the length of the cephalic segment, and composed of only 

 10 joints thickly clothed with coarse diverging seta?. Posterior antennae likewise 

 unusually short, with the 3 outer joints nearly equal in length. Maxillipeds also 

 comparatively short and stout, especially the anterior ones. Natatory legs, as in 

 the 2 preceding species, imperfectly developed, both rami of 1st pair and the 

 inner one of 2nd pair being biarticulate; spines of outer ramus unusually long 

 and slender, especially those in the 1st pair; seta attached outside the terminal 

 joint of inner ramus in all the pairs spimform ; apical spines of this joint in 4th 

 pair rather produced, the inner one being somewhat longer than the outer. Last 

 pair of legs extremely small and attached to the outer corners of the last trunk- 

 segment, proximal joint confluent with the segment, distal joint narrow, sublinear 

 in form, with the lateral spine issuing from the apex itself, immediately inside 

 the apical seta. Ovisacs, according to Lilljeborg, of small size. Seminal receptacle 

 rather large, with the anterior part very broad, forming on each side a rounded 

 expansion, posterior part somewhat produced, linguiform. 



Colour whitish, with a faint rosy or violaceous tinge. 



Length of adult female 0.75 mm. 



Remarks. This is a very distinct and easily recognisable species, differing 

 conspicuously in its outward appearance from those described in the preceding 

 pages, and somewhat recalling certain species of the genus Plat > joy clops, especially 

 P. fimbriat'iis (Fischer). It is, however, a genuine Cyclops, as shown by the struc- 

 ture of the legs, and in this respect closely approaches the 2 preceding species. 



Occurrence. Some specimens of this pretty form were taken last summer 

 in Mj0sen, near Hamar, from a depth of 4 6 fathoms, muddy bottom. According 

 to Lilljeborg, it descends in some instances to considerably greater depths, having 

 been found by that author in one of the Swedish lakes (Ifsjo) down to 25 

 fathoms. It was indeed for this reason that the specific name ab/jssicola was 

 proposed. 



Distribution. Sweden (Lilljeborg). 



31. Cyclops varieans, G. 0. Sars. 



(PI. XXXIII). 



Cyclops raricans. G. 0. Sars, 1. c.. p. 43. 

 Syn.: Cyclops orientalis, Uljanin. 



Specific Characters. Female. Body not very slender, with the anterior 

 division oval in form, greatest width somewhat exceeding half the length and 



