WwW 
FRESHWATER ALG. 
Genus OscILLATORIA Vaucher. 
44, OSCILLATORIA PROBOSCIDEA. 
Oseillatoria proboscidea Gom., tom. cit., p. 209, Pl. VI., figs. 10, 11. 
Diam. trich. = 12 p. 
fTab.—F¥reshwater pond in ice off Black Island, McMurdo Strait, December 31st, 
1902. 
Isolated filaments, very similar to Gomont’s fig. 11. 
45, OSCILLATORIA SUBPROBOSCIDEA. 
(Pl. 1, fig. 66.) 
Oscillatoria subproboscidea W. and G. 8S. West, op. cit., p. 298, Pl. XXYV., figs. 91-94. 
Hab.—Freshwater pond among eskers, four miles north of Black Island, upon 
ice, McMurdo Strait, September 12th, 1902; very rare. 
46. OSCILLATORIA IRRIGUA. 
Oscillatoria irrigua Kiitz., Phye. gen. (1843), p. 189; Phycol. Germ., 1845, p. 160; Gomont, tom. cit., 
pp. 218-219, Pl. VI., figs. 22, 23. 
Diam. trich. = 7-8 p. 
ITab.—Gap pond, Winter Harbour, December 15th, 1903. . 
47, OSCILLATORIA SIMPLICISSIMA. 
Var. ANTARCTICA var. n. 
(Plate I., figs. 60-64.) 
Oscillatoria simplicissina Gom., tom. cil., p. 219, Pl. VIL., fig. 1 (0. tenuis f. eruginosa Sauter in Raben- 
horst, Alg., 1874, No. 2388). 
Trichomatibus szepe valde elongatis, flexilibus, plerumque flexuosis, inter cellulas 
non constrictis, massa intercellulari inflato et refringenti imterruptis, apice recto neque 
attenuato neque capitato ; cellula apicali superne hemisph:erica ; protoplasmate 
homogeneo vel subgranuloso. 
Diam. trich. = 8»; long. cell. = 2-3 yp. 
fab.—Freshwater pond in ice off Black Island, McMurdo 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 flexuous character and the abundant occurrence of inflated bi-concave 
intercellular masses (fig. 60). The apices of the trichomes were perfectly straight and in 
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