Freshwater Algae ■ 17 a 



HYDRODICTYACEAE. 

 Pediastrum Meyen. 

 Fediastrutn Boryanum (Turp.) Menegh. 



This was about the most frequent alga of the collections. It was secured 

 in all possible habitats — tundra ponds, brackish ponds, mud and bottom 

 deposits, and plankton — and was common at the following localities: Teller, 

 CoUinson point, Demarcation point, Bernard harbour, and Herschel island. 



Pediastrum Boryanutn (Turp.) Menegh. var. granulatum (Kiitz.) Braun 



This variety is not uncommon to North America although it was only 

 found at Herschel island. It has not been previously recorded for the arctic 

 regions of America. 



Pediastrum glandulif erum Benn. (Plate III, fig. 1) 



This species is one of the less frequent of the genus. The glandular processes 

 on all were quite typical. I cannot find any previous record for this species in 

 North America or arctic regions, although I have recently found it near Winnipeg. 

 It occurred in small quantities in collections from the lagoon lake at Teller, in 

 the plankton of the big lake at Bernard harbour, and at Chantry island. 



Pediastrum integrum Nag. (Plate III, fig. 2) 



A few individuals of this species, with its very angular walls and the- sherS' 

 processes, were found in the water of the big lake at Bernard harbour, and one 

 in the brackish pond in the same locality. 



Pediastrum tetras (Ehrenb.) Ralfs 



This species was second in abundance to P. Boryanum. The 4-celled form 

 was common at Teller, and at Bernard harbour. At Herschel island both 4- and 

 8-celled forms were frequent. 



VAUCHERIACEAE. 



Vaucheria DC. 



Vaucheria terrestris (Vauch.) DC. 



Fragments of Vaucheria occurred in a small number of the collections, 

 but the only place where any quantity was secured was at Cape Bathurst, 

 July 26, 1916. Reproductive organs were not numerous and mostly in the 

 earlier stages; a few ripening oospores were present. 



CLADOPHORACEAE. 



Cladophora Kutz. 



Cladophora fracta (Dillw.) Kiitz. > 



Small masses and numerous fragments of this alga were common at Teller, 

 and at Bernard harbour, especially in the collections from tundra ponds. ,, 



Cladophora sp? 



A few fragments were found in a fish stomach (Coregonus sp.). Port Epworth, 

 October 4, 1915. Identification of the species was not possible. 



Rhizoclonium Kutz. 

 Rhizoclonium hieroglyphicum (Ag.) Kiitz. var. tortuosum (Kiitz.) Stockm. 



Amongst the Cladophora from a tundra pond at CoUinson point was a 

 quantity of this Rhizoclonium. As it did not seem quite typical I submitted 

 some to Professor G. S. West and he identified it as the var. tortuosum which 

 I believe is new to this continent. 



49069—2 



