110 



Posterior antennae with the natatory setae reduced to slight rudiments, the 

 longest of them scarcely extending beyond the middle of the penultimate joint. 

 Caudal rami rather slender and scarcely at all curved, apical claws very thin, 

 subequal,.and exceeding somewhat in length half the ramus. 



Colour dark brownish grey. 



Length of adult female about 1 mm. 



Male unknown. 



Remarks. This form was first described as a distinct species by the 

 present author in the year 1890, it having previously been confounded with 

 Ilyocypris biplicata (or gibba). The form described by Vavra in 1891 as 

 Ilyocypris gibba var. repens, and subsequently recorded by Daday as the type 

 of the present genus, is unquestionably identical with the species here under 

 question. 



Occurrence. -I have met with this form rather abundantly near Christian!;], 

 in some shallow ditches with grassy bottom and slowly floating water. The 

 animal is rather sluggish, being quite devoid of swimming power and only 

 adapted for slowly crawling on the bottom or along the aqvatic plants growing 

 on it. In the fresh state it is moreover easily recognised from the species of 

 the genus Ilyocypris by the dark brownish colour of the shell. 



Distribution. Sweden, British Isles, Germany, Switzerland, Hungary, 

 Turkistan. 



Group 6, Eucyprides. 



Remarks. To this group I refer the more typical forms of the sub- 

 family Cyprinse, all of which were formerly included in the genus Cypris. In 

 recent times however several nearly-allied genera referable to this group have 

 been established, 8 of which will be treated of in the sequel, as represented 

 in the Fauna of Norway. 



Gen. 18. Cypris, O. Fr. Muller 1776 (sens, strict.). 



Syn: Eurycypris, O. W. Mttller. 



Generic Characters. Shell very tumid and of rather firm consistency, 

 with the dorsal face more or less gibbously vaulted, the ventral flattened. 

 Valves subequal, with the anterior and posterior edges in most cases coarsely 

 dentate and the inner duplicatures moderately broad. Both pairs of antennae 

 powerfully developed and well adapted for swimming, the posterior ones with 



