FRESHWATER ALGM 293 



Genus OSCILLATORIA Vaucher 



62 Oscillatoria limosa Ag. 



1812; Gomont, I.e. p. 230, t. 6, f. 13. 



Crass, trich. 14-17 n. 



Hob. Pony Lake, Coast Lake, and Green Lake. Also ponds on Mt. Erebus. 



This species was abundant in the above-mentioned localities, and in most cases 

 was remarkable for the shortness of its filaments, many of which were only 40-60 M in 

 length. 



63 Oscillatoria sancta Kiitz. 



Tab. Phycol. I, p. 30, t. 42, f. 7 ; Spec. Alg. 1849, p. 246 ; Gomont, l.c. p. 229, 

 t. 6, f. 12. 



Crass, trich. 12.5-15 M. 

 Hob. Pond, Cape Barne. 



64 Oscillatoria subproboscidea sp. n. (PI. XXV, Figs. 91-94) 



0. trichomatibus inter varias Oscillatorias libere natantibus, olivaceo-eerugineis, 

 elongatis, rectis vel leviter flexuosis, juxta apicem attenuatis et plerumque subuncinatis, 

 inter cellulas non constrictis ; cellulis diametro trichomatis circiter 2|-plo brevioribus, 

 non elongatis apicem versus; cytioplasmate minutissime granulatis, dissepimenta 

 non granulata; cellula apicali brevi et convexo-obtusa, membranam convexam leviter 

 incrassatam praebens. 



Crass, trich. 8.2-9 M; long. cell. 3-4 ft. 



Hab. Coast Lake. 



This species was frequent in the sediment under the ice of Coast Lake, mixed with 

 0. tennis and others. It is perhaps nearest to 0. proboscidea Gomont, but is consider- 

 ably narrower, with straight trichomes and rather longer cells. The apex is also 

 different, as although it is somewhat suddenly attenuated and frequently uncinate, 

 it is never capitate. 



In thickness 0. subproboscidea is similar to 0. chalybea, but there are no constric- 

 tions between the cells as in the latter species, and the trichomes are only attenuated 

 close to the apex. The apical cell is also short and possesses a calyptra. 



65 Oscillatoria tennis Ag. 



1813 ; Gomont, l.c. p. 240, t. 7, f. 2, 3. 



Crass, trich. 7-10 n. 



Hab. Coast Lake. 



This species was frequent amongst 0. subproboscidea and a small quantity of 

 0. limosa Ag. The trichomes were typical in all respects, and varied considerably 

 in thickness. 



