1 92 I. No. 4. THE PHYTOPLANKTON OF SOME NORWEGIAN LAKES. 



IV. SYSTEMATIC ACCOUNT OF THE MORE 

 INTERESTING SPECIES. 



C /ass Myxophyceæ. 

 Order Coccogoneœ. 

 Family Chroococcacece. 



Genus Cliroococcus Naegeli 1849. 



Cliroococciis liiiuicticits Lemm. 



Lemmermanx : Beitr. Kenntn. Planktonalg. I. 



This species was only found in three lakes, in none of which it occur- 

 red abundantl}'. The Alga is not previously recorded from the Norwegian 

 freshwater plankton. It seems to be quite ubiquitous in its distribution. 



Genus Aphanocapsa Naegeli 1849. 



Aphanocapsa dclicatissima W. & G. S. West. 



W. & G. S. West : Periodicity Phytopl. Brit. Lakes. 



Aphanocapsa delicatissima occurred abundanth' in the Orrexandet lake, 

 and the Figgenelven ri\er, both in Western Norway. — This species is 

 previously recorded principalh' from the British Islands, and it seems toge- 

 ther with the other plankton-species of Aphanocapsa (A. chichista) to be a 

 characteristic constituent of the so-called Caledonian plankton. — It may, 

 however, be that it has been overlooked in the past, owing to its delicate 

 appearence, and that it will be found to have a wider distribution, if looked 

 for carefullv. 



Aphanocapsa clachista W. &: G. S. West. 



W. & G. S. West : Some Freshw. Alg. West Indies. 



This species occurred abundantl}' in the plankton of the lake Vaale- 

 sjeen, and was scarce in the plankton of two other lakes. It is no exclusive 

 plankton species, being original^ reported on from trees and streams in 

 Dominica. 



Aphanocapsa elachista var. confcrta W. & G. S. West. 

 W. & G. S. West : Periodicity Phytopl. Brit. Lakes. 



This variety occurred in abundance in Orrevandet, together with 

 Aphanocapsa dc/icafissii/ia. Its geographical distribution is as far as known 

 the same as that of the preceding species. It is, however, doubtful whether 

 the Chroococcaceæ show any other geographical distribution than the one 

 caused by the physical conditions of their growing-places. 



