FRESHWATER ALGJE. 11 



" Rondane " in Norway, where it was found on snow. The Antarctic individuals, like 

 those described by Wille, lacked all traces of a pyrenoid. The nucleus (figs. 21-25) 

 was prominent and situated in the centre of the cell, in which respect the specimens 

 differed from those described by Wille (cf. however, his fig. 25, where the nucleus 

 appears to be quite central). Numerous discoid chloroplasts were frequently 

 recognisable in the cells, and in some cases a slightly elongated stigma could be made 

 out, not far from the bases of the cilia (figs. 21, 25). Some of the individuals were 

 practically devoid of starch, while others contained a considerable amount. The cilia 

 were so delicate that in some of the individuals it was only possible to trace them a 

 very short way, but they appeared in general to be a little longer than the body of the 

 cell (fig. -21). 



Some of the individuals were of a more elongated form than those described and 

 figured by Wille (long. cell. = 13 //, ; lat. cell. = G p., figs. 23, 24), but in view of their 

 resemblance to the type in other respects, I do not think that they belong to a different 

 species. 



PROTOCOCCACE.E. 



Genus TROCHISCIA Kiitz. 

 5. TROCHISCIA CRASSA. 



Trochiscia crassa Hansg., Physiol. und Algol. Mltteil. (1800), Tub. I. ; Prodi', d. Altrejfl. v. 

 Bohmen, ii. (1*1)2), pp. 240-241. 



Diam. cell. =: 50-55 /j.. Cell-wall deep brownish-red, opaque. 

 Jlnti. Granite Harbour, freshwater pond, January 20th, 1902. 



ULOTRICHACEyE. 



Genus ULOTHRIX Kiitx. 



G. ULOTHRIX SUBTILIS var. VARIABILIS. 



Ulotliri.,' xnhlilis Kiitz., Phycol. Germ. (1845), p. 197 ; Tub. Phycol. ii. (1852), Tab. JSii, ii-. 1. 

 Yur. rri<il>ilix (Kiitz.) Kirchncr, Alg. Schlesien (1878), p. 77. 



Crass, fil. = G-7 /u. ; cells one and a half times or twice as long as broad. 



//<(/*. Freshwater pond in ice off " Black Island," McMurdo Strait, December 31st, 

 1 1)02 ; Gap pond, Winter Harbour, December 15th, 1903 (in both cases on surface 

 of Phormidium). 



This form was not common. 



