COLLECTED IN THE SOUTH ORKNEYS. 321 
(cf. text-fig., C *) ; in many cases the mucilage was of a deep red colour, 
probably owing to the colouring-matter of the cell having diffused out and 
stained the mucilage under the influence of the preserving fluid. This 
deeply coloured mueilage made details of the enclosed cell difficult to 
determine, but so much could be seen that it has a moderately thickened 
wall and granular contents ; a pyrenoid (7) was only very rarely visible. 
Numerous small particles were generally adhering to the surface of the 
mucilage, and this still further obscured the enclosed cell. The resting-cells 
of the second type were far less numerous than those of the first. They 
appear to correspond to cells observed by Lagerheim f and referred by him 
to Chlamydomonas sp. ; similar cells were noticed by Wittrock +. I am 
unable to add to our knowledge of these cells and have consequently merely 
described them in the systematic portion of this paper as Chlamydomonas sp. ? 
Inasmuch as these cells are of about the same dimensions as the smaller 
resting-cells of the first type (described above) and as the two kinds of cells 
occur side by side, they may be merely different stages of the same organism. 
Apart from the forms hitherto mentioned, the only other constituents of 
the red snow from the South Orkneys are Diatoms, which are, however, 
found only as isolated individuals (Melosira Sol, Kütz., Coscinodiscus radiatus, 
Ehrenb., etc.). It seems probable that only the red resting-cells above 
described and the Aaphidonema ате true components of this flora, and that 
the remaining forms are introduced by the agency of wind and (?) animals 
(possibly the penguins). The Seotiella is perhaps an introduction from the 
yellow snow flora (which is not often very far separated from the red 
snow, cf. p. 298), while the Diatoms (which are in great part marine 
forms) probably come from the sea-shore. 
The complete list of Algæ found in the red snow from the South Orkneys 
is as follows :— 
Chlamydomonas nivalis (Sommerf.), Melosira Sol, Kütz. 
Wille ? (— Coscinodiscus radiatus, Ehrenb. 
Chlamydomonas sp. (ef. above). Navicula borealis (Ehrenb.), Kütz. 
Scotiella antarctica, F. E. Fritsch. Amphora ovalis, Kütz. 
Raphidonema nivale, Lagerh. (0 Triceratium sp. (T. arcticum, 
ŒE dogonium sp. | Bright ?). 
Zygnema sp. (one filament). 
* The mucilage-sheath was often considerably broader than is shown in this figure. 
+ Lagerheim, Ber. Deutsch. Bot. Ges, x. 1892, рр. 523, 529, pl. 28. fig. 10. 
+ Wittrock, “ Om snüns och isens Flora,” loc, cit. 
