134 KAARE MÜNSTER STRØM. 



27. Microcoleus sociatus W. & G. S. West. 



W. & G. S. West: Welwitsch African Freshwater Algæ. 



page 70 (sep.) 



The dimensions, and the number of trichomes in the vaginae 



are just the same as recorded by West. 



Messrs. West give no figure and I have therefore drawn 



the species. (Pl. II Fig. 16). 



Pjatigorsk, from the sulphur springs, lat. trich. 2,5 a; long 



cell. 3,5— 4 ^f; 



Family Scytonemuceæ. 

 Genus Tolypothrix Kiilz. 



28. Tolypothrix distorta Eiilz. 

 Kasbek — Mleti. Abundant. 



Class Scliizoinycetes. 



Family Beggi'atoacese. 

 Genus Beggiatoa Trevisan. 



29. Beggiatoa sp. 



The bacterium grew^ between Chara. The species could 

 not be determined as the bacterium was dried, and the 

 specific features cold not be observed with accuracy. It 

 seemed, however, to belong to Beggiatoa alba (Vauch.) 

 Trevisan. 

 Zei valley. 



Class Chlor ophyceæ. 



Order Conjugatæ. 



Family Desmidiaceæ. 



Genus Closterium Nitzsch. 



30. Closterium striolatum Ehrbg 

 Wladikaokas — Kasbek, long. 240 ^<; lat. 42 jt<. 



31. Closterium Venus Kiitz. PI. II Fig. 12. 

 Wladikaokas — Kasbek, long. 16 f.i; lat. 11 /.i. 

 Abundant. 



