58 



both pairs of antennae. In the structure of the natatory legs, the unusual 

 prolongation of the terminal joint of the inner ramus is rather characteristic. The 

 last pair of legs are also distinguished by the presence on the distal joint of 2 

 slender, subequal setae, the inner one replacing the short lateral spine found in 

 the species of Cyclops (sens, strict.). Finally, the very characteristic form of the 

 seminal receptacle may be here mentioned. 



To the fauna of Norway belong 4 well-defined species, to be described 

 below, and also a number of exotic species may be adduced to the same genus. 

 Thus it is evident that the 2 African species, C. emini Mr&zek and C. neglectus 

 G. 0. Sars, recorded by the present author in his paper on the Copepoda of the 

 Tanganyika Expedition, are referable to this genus, as is unquestionably the case 

 with the North American species, C. edax Forbes, perhaps also with the South 

 American species, C. spinifer Daday. I am likewise of opinion that C. gracilis 

 Lilljeborg must be placed within the present genus, in spite of the reduction of 

 the number of joints in the anterior antennas, and the imperfect development of 

 the legs, as this form otherwise has an unmistakable resemblance to the species 

 here under consideration. 



33. Mesoeyelops obsoletus (Koch). 



(PL XXXV). 



Cyclops obsoletus, Koch, 1. c. Heft 21, Tab. 5. 

 Syn: Cyclops Leuckarti, Claus. 

 simplex, Poggenpol. 



,. Scourfieldi, Brady. 



Specific Characters. Female. Body moderately slender, with the anterior 

 division regularly elliptical in outline, greatest width slightly exceeding half the 

 length and occurring about in the middle. Cephalic segment very large, almost 

 twice the length of the 4 succeeding segments combined. Last trunk-segment 

 very small. Tail slender, exceeding in length 3 / 3 of the anterior division; genital 

 segment long and narrow, fully attaining the length of the 3 succeeding segments 

 combined, and almost cylindrical in form. Caudal rami of moderate length, though 

 scarcely as long as the last 2 segments combined, and only slightly divergent; 

 seta of outer edge rather far from the apex, being attached a little behind the 

 middle; apical setae comparatively slender and elongated, the inner mediate one 

 attaining the length of the tail, seta of outer corner rather produced, though 

 scarcely half as long as that of the inner. Anterior antennae long and slender, 

 reaching, when reflexed, almost to the end of the 3rd segment, outer joints rather 

 narrow and bordered by a delicate hyaline rib, which on the last joint, at some 



