53 



Acrochæte Pringsh. 



95. A. parasitica Oltm., К. Rosenv. Deux. Mém. p. 114. 



Bolbocoleon Pringsh. 



96. B. pilifenim Pringsh., K. Rosenv. Grl. Havalg. p. 134, 

 Deux. Mém. p. 115. 



The species was abundant in old fragments of Stictyosi- 

 phon tortilis, which were found in company with Pylaiella 

 littoralis and Isthmoplea sphœrophora floating in the water, in 

 a hole in the ice of the lagoon, north of Кар Dalton. It was 

 found sterile in July. 



Gr. or.: Кар Dalton (N. H.). 



Fam. Ulothncaceæ. 



Ulothrix Kütz. 

 Key to the species : 



I. Filaments 14 — 80^ thick generally containing 2 — 3, rarely 



1 or 4 pyrenoids in each cell U. flacca 



II. Filaments 7 — 23 ц thick containing only one pyrenoid in 

 each eel]. 

 A. Ghromatophore thickened in one end. 



a. Without rhizoids. 



o. Basal cell tapering downwards. 



1 . Ghromatophore generally almost fills the length 

 of the cell U. pseudoflacca f. typica 



2. Ghromatophore does not fill the length of the 

 cell U. pseudoflacca f. tenuior 



oo. Basal cell discoidally widened at the base 



U. scutata 



b. With rhizoids, 



o. Basal cell discoidally widened at the base, no 



coalescent filaments U. scutata 



oo.» Basal cell slightly narrowed at the base, coales- 

 cent filaments occur. 

 1. Filaments straight, the coalescent filaments 



