FRESHWATER ALG. 
bo 
“I 
Var, ANTARCTICA var. nov. 
. (Pl. II., figs. 87-90.) 
Filis elongatis, rectis vel flexuosis, interdum  tortuosis ; vaginis hyalinis, plus 
minusve tenuibus, levibus, ut videtur, state provecta non crassis; trichomatibus 
eerugineis, apice haud vel raro attenuato, truncato, sepe massa intercellulari inflato 
et refringenti interruptis; cellulis diametro trichomatis quadruplo ad_ sextuplo 
brevioribus, cytoplasmate sxepe cum granulis magnis, dissepimentis plerumque non 
granulatis; apice trichomatis interdum capitato, membrana cellule apicalis superne 
plus minusve distincte incrassata in forma calyptre. 
Diam. fil. = 8-13; diam. trich. = 7-12 p. 
Hab.—Same as the type, but the variety was considerably more abundant. 
At first there seemed to be good grounds for establishing this variety as a 
distinct species, as it differs from the type in several prominent respects, viz., 
the thin character of the sheath, evens in older filaments; the rare attenuation of 
the apex of the trichome; the frequent presence of a prominent calyptra and 
the marked capitate habit of many of the trichomes; the presence of numerous 
biconcave masses of refringent intercellular substance, which generally bulge a little. 
None of these characters except the thinness of the sheath and the occurrence of 
intercellular masses is, however, constant. The apex of the trichome may be flat 
and rounded without any development of a calyptra or even a perceptible thickening 
of the outer membrane (fig. 88); or the apical cell may have a prominent calyptra 
without possessing a capitate character (fig. 89); or the apex may be distinctly 
capitate with only a slight thickening of the outer membrane (fig. 90); or lastly 
the apex of the trichome may be more or less markedly attenuated, capitate and 
provided with a well-marked calyptra (fig 87). It is obvious that these different 
forms of apex connect the variety with the type, a connection which is also 
established by the identical width of the trichomes in the two cases and the 
extremely flat cells. Should the different types of apex be constant we would 
have f. attenuata, f. capitata, f. simplex, etc., of this variety, but it is possible that 
some or all of them are merely stages in development. 
The apical cell in the capitate trichomes was always very transparent and devoid 
of contents. Occasionally the two end-cells of the trichome showed these characters. 
In a few cases the cells near the apex of the trichome exhibited a faint constriction 
at the dissepiments (fig. 89). 
32. LYNGBYA MARTENSIANA. 
Lyngbya martensiana Menegh., Conspect. Algol. euganex, 1837, p. 12; Gomont, op. cit., xvi. (1892), 
p. 145, PL. IIL, fig. 17. 
Diam. fil. = 8-9; diam. trich. = 6-7°5 p. 
ITab,—F reshwater pond in ice off Black Island, McMurdo Strait, December 
31st, 1902; Granite Harbour, January 20th, 1902, 
