•156 KAARE MÜNSTER STRØM. 



Genus Tolypothrix. Külz. 1843. 



19. Tolypothrix tenuis. Kütz. Phyc. gen. Johs. Schmidt: 

 Cyan. Dan. 



Not uncommon in some samples. Size: lat. tiich. 6 — 7 ft. 



Family Stigonemaceæ. 

 Genus Hapalosiphon. Nägeli 1849. 



20. Hapalosiphon intricatus. W. West in Journ. of 

 Botany XXX. 



Common. Size: lat. fil. 5—6 /li. 



21. Hapalosiphon Hihernicus. W. & G. S, West: New Brit. 

 Freshw. Algæ. 



Common. I find both this and the preceding species to be 

 generally distributed in Norway. Recent investigations of pro- 

 fessor Wille confirm this fact. Size: lat. fil. 9,b /n & 5 ^. 



Genus Stigonema. Ag. 1824. 



22. Stigonema ocellatum. (Dillw.) Thur. Ess. 

 Very common. 



23. Stigonema panniforme. (Ag.) Kirchn. Algenfl. Schles. 

 Rare. Only in a single sample. 



24. Stigonema minutum. (Ag.) Hass. Brit. Freshw. Algæ. 

 Rare. 



25. Stigonema inatnillosum. (Lyngb.) Ag. Syst. Alg. 

 In great quantity in a single sample. 



26. Stigonema sp. 



Some Stigonema-specimens were observed in a very curious 

 state, which I have figured. (PI. V, Fig. 2, and text-figures.) I had 

 the impression that it was a germination of resting-cells. The 

 simple filaments which are growing out were also observed free- 

 floating in the same samples. The material was, however, 

 preserved in acetate of potassium, and I have not observed the 

 curious stage in the nature. Nothing can be said about the 



