32 a 



Canadian Arctic Expedition^, 1913-1918 



Hyalotheca mucosa (Mert.) Ralfs . (Text fig. 6) 



This desmid with its enormously wide sheath, was fairly common in one 



of the tundra ponds at Teller. A few small fragments were also found in the 



material from Herschel island. It is a species common in the warmer temperate 



regions and I do not think it has been recorded before from arctic waters. 



Diameter of sheath lOO-llO/i, diameter of cells 15ai, length of cells 18-20^. 



Fig. 6. Hyalotheca mucosa (Mert.) Ralfs. A photomicrograph to show diameter of the mucus sheath 

 indicated by the broken line X 340. 



Stephanokontae. 



OEDOGONIACEAE. 



Bulbochaete Agardh. 

 Bulbochaete sp. 



Fragments belonging to this genus appeared in collections from nearly all 

 localities visited by the Southern Party. They were fairly abundant and in 

 all cases bore exceedingly long bristles. No reproductive stages were present. 

 Hence it was impossible to identify the species. 



Vegetative cell: diameter 15-21ju; length 20-25/x. 



Oedogonium Link. 

 Oedogoniutn sp. 



Filaments of Oedogonium, more or-less fragmented, were even more frequent 

 than those of Bulbochaete. With the exception of the material from Herschel 

 island, in which sexual organs were present, it was found only in the vegetative 

 condition, so that identification of species was limited to the Herschel island 

 collections. 



Oedogonium nodulosum Wittr. (Plate IV, fig. 15) 



A few small filaments of this species were observed in the collection from 

 the Hippuris swamp, Herschel island. It is a monoecious form with the vege- 

 tative cells bearing two constrictions dividing each cell into three wide parts 

 with narrower parts connecting them. The plants observed were somewhat 

 smaller then the type. It has been recorded from Europe, Asia, and South 



