Freshwater Diatoms 37 a 



Rhabdonema Ktitz. 



Rhabdonema arcuatum (Ag.) Ktitz. 



This also is a marine form found in the mud of the lake at Bernard harbour, 

 February, 1916. 



PENNATAE. 



DiATOMEAE. 



Diatoma DC. 

 Diatotna vulgare Bory 



This species was only found in two collections made August, 1915, at 

 Bernard harbour. A few were seen in the sample obtained from the brackish 

 pond and more were found in the plankton from the big lake. It was not abundant 

 although found in most freshwater areas. 



Denticula Ktitz. 

 Denticula tenuis Ktitz. 



This species was somewhat more frequent than the last named. It was 

 found at Camden bay, July 4, 1914, in the big lake at Bernard harbour, June, 

 1915, July, 1916, and in the stomach of a fish taken October 4, 1915. 



Opephora P. Petit. 

 Opephora Schwartzii (Grun.) P. Petit 



This species was found only in a collection taken from the lagoon lake at 

 Teller, August, 1913. It was not numerous. 



Synedbbae. 

 Synedra Char. Em. 



Synedra amphicephala Ktitz. 



This also was very limited in its distribution, being found only at Bernard 

 harbour, at the creek mouth and the big lake, July, 1915. 



Synedra Ulna (Nitz.) Ehr. 



This diatom was fairly plentiful, being found in freshwater samples obtained 

 in July and August, 1913, at Teller, and at Bernard harbour during July and 

 August, 1915, and February, 1916, in the plankton; also in a fish stomach 

 obtained October 4, 1915. 



Asterionella Hass. 

 Asterionella formosa Hass. 



This is a common lake plankton diatom but was not very numerous in these 

 northern collections. It was found in the plankton of the big lake, Bernard 

 harbour, July and September, 1915, June, 1916, and also at the creek mouth, 

 July, 1915. 



EUNOTIEAE. 



Eunotia Ehr. 

 Eunotia gracilis (Ehr.) Rab. 



This species was found only at Teller, where it occurred both in the brackish 

 pond and the lagoon lake, August, 1913. It was not very numerous. 



