20 A Canadian Arctic Expedition, 1913-1918 



Penium spirostriolatum Barker (Plate III, fig. 6) 



A few individuals of this beautiful desmid occurred in the Hippuris swamp 

 at Herschel island. It also has not been previously recorded from arctic America. 



Closteriutn Nitzsch. 



Closterium Cornu Ehrenb. (Plate IV, fig. 16) 



This was a very common species from the tundra pond and the pond 

 between the lake and sea at Teller. It was found also on Pihumalerksiak island 

 (Cockburn point). The majority of specimens were more curved then the type 

 form. Not previously recorded from American arctic regions. 



Closterium Dianae Ehrenb. 



- This little Closterium was found with some plankton gatherings, August, 

 1915, from the big lake at Bernard harbour. 



Closteriutn didymoctocum Corda var. striatum nov. var. (Text fig. 2) 



Semicellulae membrana atrofulva, striata, striis 13-15 transversis bene 

 distinctis. 



Cells large as in type, 9-12 times longer than their diameter. Outer 

 margin slightly curved, inner margin almost straight. Sides gradually attenuated 

 towards the apices which are broad and truncate with rounded, somewhat 

 slightly recurved angles; cell wall reddish brown, definitely striate, 13-15 striae 

 visible across the cell; annular thickening of darker colour at each apex. 

 Length, 340^. 



It was not common but all individuals seen were the same. It was 

 obtained on Herschel island. 



Fig. 2. Closterium didymoctocum Corda var. striatum nov. var. X 475; semi-cell showing the striated 

 wall and the regular characters of the apex. 



Closterium Jenneri Ralfs 



The type form was found in the Hippuris swamp at Herschel island. A 

 form with apices less curved than type was found in a collection of bottom 

 deposits and plankton from Teller. 



Closterium moniliferum (Bory) Ehrenb. 



This was only found in the lagoon lake at Teller. It is commqn in Canada 

 and the United States, but had not been previously recorded from the arctic 

 regions of America. 



Closterium parvulum Nag. 



This small Closterium is common in arctic regions, but only appeared in 

 collections from two localities and was not abundant. It was found with other 

 species of this genus in the lake at Teller, and in a lagoon just west of Martin 

 point. 



