81 



Colour generally dark bluish grey. 



Length of adult female about 0.75 ram. 



Remarks. In its general appearance this form somewhat resembles the 

 Receding species, but is of much smaller size and has the body less robust, 

 [t moreover exhibits several well-marked differences in the structure of the 

 intennaB and legs, as indicated in the above diagnosis. The Cyclops pygmceus 

 of Rehberg is unquestionably identical with the present species. 



Occurrence. I have taken this form in similar localities to those in 

 which the preceding species has been found. It also occurs occasionally at the 

 borders of large lakes or in closed lagoons formed by the reflux of the water 

 in these lakes during the dry season. 



Distribution. Throughout Europe, Turkestan (Uljanin), Australia (G.O.Sars). 



48. Platycyclops fimbriatus (Fischer). 



(PI. L). 



S fimlriatus, P'ischer, Beitrage zur Kenntniss der Cyclopiden (Fortsetzuug). Bull. Soc. Imp. 



Moscou 1853, p. 94, PI. Ill, figs. 1928, 30. 

 Syn: Cyclops crassicornis, G. 0. Sars (vix Miiller). 



Specific Characters. Female. Body comparatively robust, with the an- 

 terior division, as in the 2 preceding species, pronouncedly depressed and oval 

 in outline. Cephalic segment large, considerably exceeding in length the 4 suc- 

 ceeding ones combined, and narrowly rounded in front. Last trunk-segment with 

 the lateral parts slightly produced and clothed with stiff, posteriorly-curving hairs, 

 about equalling in length 2 / 3 of the anterior division, and slightly tapered 

 distally; genital segment longer than the 2 succeeding ones combined, and some- 

 what dilated in front; anal segment shorter than the preceding one, and nearly 

 transversely truncated at the end. Caudal rami much more prolonged than in 

 the 2 preceding species, almost attaining the length of the last 3 segments 

 combined, and rather remote at the base, being narrowly linear in form and only 

 slightly divergent; seta of outer edge attached at some distance from the end, and 

 somewhat dorsally; upper face of each ramus exhibiting, just in front of this 

 seta, a short transverse row of small denticles; middle apical setae rather strong, 

 ind clothed in their median part with scattered, stiff hairs, the inner one being 

 learly twice as long as the outer and about the length of the tail; seta of inner 

 corner a little longer than the spine of the outer. Eye large and conspicuous, 

 interior antennae scarcely more than half as long as the cephalic segment, and 

 rather dilated at the base, being composed of only 8 joints, densely clothed with 



11 Crustacea. 



