Freshwater Algae 21 a 



Closterium rostratutn Ehrenb. 



Although this species is more northern than C. setaceum, it was found in 

 small numbers. It occurred only in the Hippuris swamp at Herschel island. 



Closterium setaceum Ehrenb. 



This plant is much rarer than the preceding species, especially in arctic 

 and subarctic areas, yet it was more plentiful in proportion to the numbers of 

 other species. It was found in a collection of bottom deposits and plankton 

 from the lake and from the pond between the lake and sea at Teller. 



Closterium striolatum Ehrenb. 



This is a very common species and is well known from almost all parts of 

 the earth. It occurred in the lake, brackish pond, and tundra ponds at Teller, 

 and in the Hippuris swamp at Herschel island. 



Closterium Venus Kiitz. 



This species was not in great abundance in any one locality, although 

 fairly common in two ponds at Teller. It was also found at Chantry island, 

 Herschel island, and at Bernard harbour. 



Pleurotaenium Nag. 



Pleurotaenium Trabecula (Ehr.) Nag. forma clavata (Kutz.) W. & G. S« 

 West (Plate III, fig. 16) 



The type form of this species has been found in Greenland and in a few 

 other arctic localities, but the form clavata has only been previously recorded 

 from a few localities in France, Germany, Italy, Sweden, the British Isles and 

 the United States. Three individuals of this form were found in material from 

 a drying tundra pond at Demarcation point. May 14, 1914. 



Pleurotaenium truncatum (Br^b.) Nag. 



This species was found only in the lagoon lake at Teller, where it was not 

 uncommon. 



Euastrum Ehrenb. 

 Euastrum ansatum Ralfs 



This species occurred in the lagoon lake at Teller, and in the swamp at 

 Herschel island. At both localities it was fairly common. 



Euastrum bidentatum Nag. 



This species was the most common of the genus and was found in the 

 lagoon lake, a tundra pond, and in a pond between the lake and sea at Teller, 

 also at Demarcation point, Herschel island, and in the lake at Bernard harbour. 



Euastrum binale (Turp.) Ehrenb. 



The type form occurred in small numbers at Camden bay, in the tundra 

 pond and the pond between the lake and sea at Teller, and at Herschel island. 



Euastrum binale (Turp.) Ehr. forma Gutwinskii Schm. (Plate III, fig. 13) 

 This occurred along with the type form in the tundra pond at Teller. 



Euastrum denticulatum (Kirchn.) Gay 



This species was found only in one locality. Teller, and was not very 

 abundant. 



