FRESHWATER ALG^. :13 



Genus OSCILLATORIA Vaucher. 



44. OSCILLATORIA PROBOSCIDEA. 

 Osdllatoria proloscitlea Gom., torn, cit., p. 209, PI. VI., figs. 10, 11. 



Diam. trich. = 1 2 fj.. 



I full. Freshwater pond in ice off Black Island, McMurdo Strait, December 31st, 

 1902. 



Isolated filaments, very similar to Gomont's fig. 11. 



45. OSCILLATORIA SUBPROBOSCIDEA. 



(PI. I., fig. G6.) 

 OsciUatoria subprobosrklea W. and G. S. West, op. cit.. p. 293, PI. XXV., figs. !U-'.U. 



Hah. Freshwater pond among eskers, four miles north of Black Island, upon 

 ice, McMurdo Strait, September 12th, 1902; very rare. 



46. OSCILLATORIA IRRICI A. 



Osdllatoria irrii/ua Kiitz., Phyc. gen. (1843), p. 189 ; Pbycol. Germ., 1845, p. 1GO ; Gomont, torn, cit., 

 pp. 21X-219, PI. VI., figs. 22, 23. 



Diam. trich. = 7-8 /u.. 



Ifal>. Gap pond, Winter Harbour, December 15th, 1903. 





 47. OSCILLATORIA SIMPLICISSIMA. 



V<n: ANTARCTICA var. n. 

 (Plate I., figs. GO-G4.) 



Oscillaloriit xiini>lifixxiiiut (iom., tain, ri/., p. iM'.i, PI. VII., fig/. 1 (0. tennis f. ceruginosa Sauter in Ral'cii- 

 horst, Alg., 1K74, No. 23*3). 



Triehomatibua stupe valde elongatis, tlexilibus, plerumque flexuosis, inter cellulas 

 IK Hi coustrictis, massa iutcrcellulari itiHuto ct refringenti interruptis, apice recto neque 

 attenuato nequc capitate ; cellula apicali supernc hemisphterica ; protoplasmate 

 hoiuoo-eneo vel subgranuloso. 



o o 



Diam. trich. = 8 p ; long. cell. = 2-3 /x. 



//(///. Freshwater pond in ice off' Black Island, MrMurdo Strait, December 31st, 

 1902 (on surface of a sheet of Phormidium angustissimum) ; pond among the eskers 

 which border the shore of the Western Mainland, December 2nd, 1902. 



The specimens differed from those described by Gomont in two important respects, 

 viz., their highly fiexuou.s character and the abundant occurrence of inflated bi-concavc 

 intercellular masses (fig. GO). The apices of the trichomes were perfectly straight and in 



L 2 



