No. 8.] ON SOME PRE 81 1 WATER OSTRACODA ANT) COPEPODA. 33 



of the claw, is affixed. On the other hand, there is no trace of 

 the seta generally found originating from the dorsal edge above 

 the claws. 



Biohif/iraf ( ihsrrniiions. — I first observed this elegant and 

 distinct species on the 6th July 1880 in one of my aquaries, 

 prepared on the 1st Juno same year. A single adult specimen 

 was caught by mere chance with the dipping tube, and on 

 closer examination several young ones were also found in 

 the aquary. In the course of the summer the number of 

 specimens considerably increased, and numerous individuals 

 were al different times fished up for examination and preserva- 

 tion, all of which were females. Also in another aquary pre- 

 pared with mud from a different locality, some few specimens of 

 this form appeared late in the summer. At the approach of the 

 winter I allowed the water in one of the two aquaries to eva- 

 porate, whereas the other was from time to time supplied with 

 fresh water so as to keep the mud constantly submerged during the 

 winter. Only in the first of these aquaries this form reappeared 

 the following summer 1887 together with numerous specimens 

 of two other Cypridida? to be described below, and also this year 

 but the one sex was represented. The species was not observed 



two aquaries, though several sue ling generations were ob- 



Uiern species, 8. fascieUa (Midler), at different seasons, without 

 ever having met with any male, I am led to the conclusion, 

 that the species of this genus are exclusively parthenogenetical. 

 As will be shown further below, I have been enabled to ascer- 

 ;lll > in a still more evident manner the absolute absence of males 

 m the case of two other Australian Cyprididae, belonging to the 



than the species of the genus Cyprinotus, a fact that is easily 

 accounted for by the less development of the natatory setae of the 



Vid.-Selsk. Forh. 1889. No. 8. 3 



