Freshwater Algae 25 a 



Cosmarium punctulatum Br4b. 



This species was almost as common as C. Botrytis and was found in nearly 

 every collection. It occxirred frequently at Teller, both in brackish and fresh 

 water,, at CoUinson point, Demarcation point, the big lake at Bernard harbour, 

 plankton and bottom samples, and in the pond in the second bay east of Bernard 

 harbour. ^ 



C. punctulatum Br^b. var. subpunctulatum (Nordst.) Borg. 



(Plate IV, fig. 3) 

 The variety was nearly as frequent as the species in the lagoon lake and in 

 a pond between the lake and sea at Teller. The variety has not been recorded 

 previously from North America. 



Cosmarium pygmaeum Arch. 



This species is almost entirely confined to Sphagnum bogs and peaty pools. 

 It was not uncommon in the collection from the Hippuris swamp, which con- 

 tained some Sphagnum, at Herschel island. 



Cosmariumi quadratum Ralfs 



This desmid was fairly abundant in the big lake at Bernard harbour, where 

 it appeared in the plankton and with other algae from the lake bottom. It was 

 also found in smaller quantity in the pond in the second bay east of Bernard 

 harbour. 



Cosmarium radiosum Wolle 



This is one of the rare algae of the expedition. Only three individuals were 

 seen altogether, one in the brackish pond and the others in the lake at Teller, 

 August 3, 1913. Its occurrence here is of interest, as it has hitherto been 

 recorded only from the United States and Ireland. 



Cosmarium rectangulare Grun. 



This is not uncommon in arctic regions and was found by the expedition 

 in two localities but not in abundance, in the tundra pond, Demarcation point, 

 and in the big lake at Bernard harbour. 



Cosmarium reniforme (Ralfs) Arch. 



This is another typical bog desmid of northern regions. It was found, 

 however, only in the Hippuris swamp at Herschel island. Not common. 



Cosmarium speciosum Lund. var. biformie Nordst. 



This is also a bog form from alpine or arctic regions. It was secured in 

 two localities, near Bernard harbour amongst stones and other algae of the 

 river bed, and in the pond in the second bay eastward. It was fairly common. 



Cosm.arium Stefanssonii sp. nov. (Text fig. 3) 



C. minutum, oblongum, sinu angusto, versus apicem haud dilatato; semi- 

 cellulae fere rectangulares, angulis inferioribus rotundatis; membrana subtiliter 

 granulata, areolata; areolae sat numerosae, ovales, paulo elevatae, scrobiculatae. 

 Long. 32-36/i; lat. 25-27/*; crass. 20-22/i. 



Cells small, 1-1| times longer than broad, moderately constricted; sinus 

 narrow, not dilated at the apex; semi cells sub-rectangular, basal angles 

 rectangular and rounded. The surface made up of canal-like depressions 

 separating more or less oval, slightly elevated areas. On each semi-cell these 



