FRESHWATER ALOJE. 



43 



The sheaths somewhat resemble those of A", ommune. The species is also somewhat 

 like N. spheericuni Vauch., but differs in the lax arrangement of the trirhomes, and the 

 presence of distinct sheath. .. 



02. ?NosTor 



Nostoc spJue-rifum Vancber, Hist. d. C'onfevv. d'eau douce (18o:-5), p. 22:1, Tab. XVI., fig. 2 ; Bovnet ct 

 Flabault, tout, cit., pp. 208-209. 



Diam. cell. veg. = 3-4 /A ; diam. hetcrocyst. = 5'5-G/j.. 



link Freshwater pond in eskers upon ice, half-way between Black and Brown 

 Islands, January 3rd, 1903. 



This form appeared as small colonies loosely attached to the surface of the 

 ( Yanophy ceous sheets, or free-floating; the colonies were spherical or ellipsoidal (or 

 slightly irregular as a result of mutual pressure) and up to 300 p, in diameter. Some 

 of the colonies were yellowish or brownish, the colour apparently being due to the 

 general mucilage. At many points large numbers of these small (and probably 

 young) colonies were densely aggregated. The trichomes were rather loosely inter- 

 woven, the only respect in which the specimens differed from the published descriptions 

 of the species. No spores were seen. 



Tt seems possible that iV. l>orin'ti Gain (/>. cit., pp. 1091-3) is a form 

 of this species. 



63. NOSTOC COMMUNE. 



Nostoc commune Vauch., oji. cit., p. 222, Tab. XVI., fig. 1 ; Bornct ct Flaliault, op. cit., pp. 203-207. 



Diam. trich. = 4 5-5 p. ; diam. heterocyst. = 6-7 /x. 



Hal. Dry ponds, AVinter Quarters, February, 1902 ; damp spots, Granite 

 Harbour, New Bay, January 20th, 1902. 



The thalli were irregularly folded, flat, membrauaceous, and of a bright bluc- 

 green, olive or olive-brown colour. In parts of the colonies the flexuous filaments 

 were densely aggregated. At some points pale brown sheaths were very conspicuous 

 around the individual trichomes, being more or less constricted between the cells. 

 In the bulk of the filaments the cells were nearly spherical or barrel-shaped, but at 

 some points more elliptical. The heterocysts were also in rare cases somewhat 

 elliptical in outline. Young stages were also present. 







Genus ANAB.ENA Bory. 



G4. ANAP..ENA ANTARCTICA sp. n. 



(PI. II., figs. 118-120.) 



Filis ssepe remotis, stratum defmituni non fonnantibus, subrectis vel modice 

 Hexuosis, in superficie Phorwidii epiphytis ; vagiuis arctis, ssepe inconspicuis ; eelltilis 

 parvis globosis vel ovalibus, diametro l-2plo longioribus ; hcterocystis globosis vel 



V * 



