44 F. E. FRITSCH. 
doliformibus, singulis, contentu exiguo, diametro cellularuam gequalibus; sporis in 
catenis dispositis, plerumque ab heterocystis remotis, cylindricis, interdum leniter 
curvatis, diametro 4-8plo longioribus, finibus rotundatis vel modice acutis, cyto 
plasmate cum granulis numerosis, membrana tenui levi. 
Diam. cell. veg. = 5°5-7 w; diam. heterocyst. = 5°5-7°5p; lat. spor. = 7°5-9p; 
long. spor. = (19)-48-58 p. 
Habh.—Gap pond, Winter Harbour, February 20th, 1904. 
This species belongs to the section Dolichospermum and appears to be most 
nearly allied to A. catenula (Kiitz.) Born. et Flah. It differs from the latter in 
being epiphytic, in the occasional presence of a narrow sheath, in the frequently 
oval shape of the vegetative cells (fig. 118), and especially in the spores. The 
latter do not show the faint constriction characteristic of A. catenula, and are 
longer and narrower (figs. 118-120); the ends are also different. The spores of 
A, catenula var. americana Collins, are somewhat more like those of <A. antaretica, 
but there are still appreciable differences, as the spores of the latter cannot be 
described as strictly cylindrical. 
Genus NopuLaria Mertens. 
65. NODULARIA SPUMIGENA. 
Var. MINOR var. nov. 
(PI. IL., figs. 104-108.) 
Nodularia spumigena Mertens, in Jiirgens. Alg. Aquat. xv. (1822), No. 4; Bornet et Flahault, tom. cit., 
pp. 245-246. 
Filis solitariis, subrectis vel varie flexuosis, elongatis, finibus non attenuatis ; 
vaginis tenuissimis, hyalinis, arctis, spe evanescentibus ; trichomatibus  leniter 
torulosis ; cellulis planis plerumque longitudine duplo ad triplo latioribus, membrana 
tenui hyalina, contentu granulis seepe magnis repleto; heterocystis transverso- 
ovalibus vel deplanatis, plerumque solitariis, sed interdum 2- vel 3-seriatis, paulo 
latioribus quam cellulis vegetativis, membrana modice incrassata, contentu seruginco 
homogeneo ; sporis ? 
Diam. cell. veg. =5-5°5 w; long. cell. veg. = 2°5-3°5 w; diam. heterocyst. = 
SOR ai/ Me 
Hab.—Gap pond, Winter Harbour, February 20th, 1904 (epiphytic on Phor- 
midium); dry ponds, Winter Quarters, February, 1902. 
This form differs from var. genwina Born. et Fiah., of N. spwimigena Mertens, 
chiefly in its smaller dimensions ; the trichomes are, however, not nearly as torulose 
as those of the type, and the thin sheath is highly diffluent, being often wanting. 
The heterocysts of the Antarctic variety agree very closely with those of var, 
