FRESHWATER ALGÆ FROM TUDDAL IN TELEMARK. 159 



Glass Flagellatæ. 



Order Euglenineæ. 



Family Euglenaceæ. 



Genus Englena. Ehrbg. 1838. 



36. Euglena sp. 



Frequent. The cells were contracted after the treatment 

 with acetate of potassium, and the species could not be deter- 

 mined. 



Order Chrysomonadaceæ. 



Family Ochromonadaceæ. 

 Genus hinobryon. Èhrbg. 1833. 



37. Dinobryon sertularia. Ehrbg. Infus. 



Very rare in the plankton of „Kovstulvatn." June 26. 



38. Dinobryon sociale. Ehrbg. 1. c. 



Rare. In a single sample. With resting-spores. 



Family Chromulinaceæ. 

 Genus Mallomonas. Perty 1852. 



39. Mallomonas acaroides. Perty : Kl. Lebensf. 

 Rather common in the plankton. 



Class Chlorophyceæ. 



Order Conjugatæ. 



Family Zygnemaceæ. 



Genus Zygnema. Agardh 1824. 



40. Zygnema sp. 



Sterile specimens of Zygnema were very common. In brooks 

 there was a great vegetation of Zygnema, even where the water 

 was running very fast. Between the filaments there was a 

 vegetation of diatoms and desmids. The green bundles of 

 Zygnema became very conspicuous in the second part of July. 



