FRESHWATER ALGÆ FROM TUDDAL IN TELEMARK. 155 



13. Oscillatoria (imphïbia. Ag. Flora X. Goniont : Mono- 

 gr;aphie. 



In sample 20. Size: lat. fil. 2.5 a. \ 



Genus Schizothrix. Kiitz. 1843. 



14. Schizothrix Muelleri. Näg. in Kiitz. Species. Algar. 

 Gomont: Monographie. 



On rocks at the shore of „Kovstulvatn.'' Rather narrow 

 specimens. Size: lat. trich. 6 — 8 /ti, long. cell. 6—7,«. 



15. Schizothrix funalis. W. & G. S. West in Trans. Roy. 

 Micr. Soc. 1896. W. & G. S. West: Freshw. Algæ. N. Ireland. 



Typical specimens of this species occurred in the same situa- 

 tion as Sch. Muelleri. The sheaths were black-brown in the lower 

 parts, and almost colourless at the ends. Size: lat. trich. 0,7 i.i, 

 lat. fil. 8—10 il. 



Family Nostochaceæ. 

 Genus Nostoc. Vaucher 1803. 



16. Nostoc sp. f juv.) 



Juvenile, and therefore undeterminable stages of a Nostoc 

 vyere found in a single sample. 



17. Nostoc sphœricwm. Vauch. Hist, des Gonferves. 

 Size: lat. cell. 4 — 5 «. 



Family Scytonemaceæ. 

 Genus Scytonema. Ag. 1824. 



18. Scytonema mirahile. (Dillw.) Bornet: Nostoc. heterocyst. 

 Born. & Flahault, Revision. 



In great abundance on irrorated rocks, forming a black- 

 brown stratum. Size: lat. fil. 16 — 18 /ti. lat. trich 10 n. lat. 

 heterocyst. 10 — 11 u, long, heterocyst. 12 ,«. 



