8 Canadian Arctic Expedition, 1913-18 



Remarks. — The quite rudimentary condition of the, natatory setae on the 

 posterior antennae proves this forni to be referable to the genus Prionocypris, 

 as recently defined by the present author. In this respect it certainly agrees also 

 with the genus Herpetocypris; but it cannot by any means be referred to that 

 genus, because the structure of the valves is wholly different and agrees closely 

 with that found in the other species of the present genus. From these it differs 

 conspicuously in the shape of the shell. 



Occurrence. — Two female specimens of this form were found in a sample 

 taken by Mr. J. B. Tyrrell from a small brook in the foothills, tributary to 

 Middle fork, Old Man river. Alberta, August 15, 1883. 



Group Cypridopsides 



Genus Cypridopsis Brady 



9. Cypridopsis aculeata (Costa) 



Occurrence. — Some few specimens of this form were raised from a parcel 

 of dried mud kindly sent to me from Mr. F. Johansen, and taken by him from 

 a pool near Ottawa. 



Genus Pionocypris Brady and Norman 



10. Pionocypris vidua (0. F. Mueller) 



Occurrence. — This form was raised rather abundantly from the same 

 parcel of mud as the above named Cypridopsis. Four specimens were moreover 

 picked up from a sample taken by Mr. F. Johansen on June 9, 1918, from the 

 Rideau canal, Ottawa, Ont. 



11. Pionocypris helvetica (Kaufmann) 



Occurrence. — -Raised in my aquaria together with the preceding ■ species. 

 Also found in a sample taken by Mr. F. Johansen from a pool in fields on 

 beaver meadow. Que., near Ottawa, on May 26, 1918. 



Group Cyclocltprides 



Genus Cyclocypris Brady and Norman 



12. Cyclocypris globosa G. 0. Sars 



Occurrence. — Some few specimens, apparently belonging to^this'species, 

 were found in a sample of lake Plankton, 0-20 fathoms, three vertical hauls 

 with net No. 4, through hole in ice, June 12, 1916, at Bernard harbour, Dolphin 

 and Union strait, N.W.T.* 



Genus Cypria Zencker 

 13. Cypria lacustris G. 0. Sars 

 Occurrence. — Found occasionally in the same sample as the Cyclocypris. 



Group Candonides 



Genus Candona Baird 



14. Candona subgibba, n. sp. 



Plate IV, figs. 1-9. 



Specific Characters. — Female. Shell rather compressed, seen laterally 

 (fig. 1) of a somewhat irregular oblong shape, greatest height scarcely attaining 

 half the length; dorsal margin considerably arched, forming behind the middle 



*See p. 16 in Part N, of this volume. 



