160 KAARE MÜNSTER STRØxM. 



41. Zygnema ericetorum. (Kütz.) Hansg. Prodromus. 

 G. S. West & G. B. Starkey: New Phytologist XIV. 



Forming green mats on damp ground. 



Genus Spirogyra. Link 1820. 



42. Spirogyra sp. 



Sterile specimens of Spirogyra were often abundant. 



Genus Mougeotia. Agardhi 1824. 



43. Mougeotia sp. 



Sterile specimens of Mougeotia were frequent. 



44. Mougeotia parvula. Hass. Brit. Freshw. Algæ, 

 Size: diam. zygosp. 21 fi, lat. celt. veget. 10 a. 



Family Desmidiaceæ. 



Sub-family Saccodermæ. 



Genus Mesotænium. Nägeli 1849. 



45. Mesotænium macrococcum. (Kütz.) Roy & Bissett. 



This species was not uncommon, and occurred also free- 

 floating. Up to 5000 feet. Size: long. cell. 35 — 36 /n. lat. cell. 

 15—16 //. 



45 a. var. micrococcum. (Kütz.) W. & G. S. West. 

 Rare. Size: long. 18,5 fi, lat. 10 fi.. A little longer than 

 the typical form. 



Genus Roya. W. & G. S. West 1896. 



46. Roya camhrica. W. & G. S. West. 



This rare species in its typical form is new to Norway. 

 The forma limnetica is previously recorded by Printz. Size: 

 long. 195 /il, lat. 7,5 /n, lat. apic. 5 /n. Slightly larger than the 

 forms recorded by messrs. West. 



