COLLECTED IN THE SOUTH ORKNEYS. 319 
away from the wall on one side of the cell. These cells are of large size 
(diam. =about 40-60 р)—оНепаз big or bigger than the largest CAlorospliera- 
cells, —and although rare are very easily recognised when present, owing to 
their distinctive colour. These cells rather recall some figured by Wittrock * 
and referred by him to Chlamydomonas nivalis, Wille, but owing to their 
large size (about 52 p) it may be doubtful whether they really belong to this 
species. Except for their larger size there is also some resemblance to the 
resting-cells of C. sanguinea T. 
In sample No. 2 a fungus was frequently to be found which, judging by its 
vonidiophore, was a species of Penicillium. A second fungus occurred in 
the other two samples, but could not be determined 1. 
In concluding this consideration of the yellow snow flora, attention may be 
drawn to one or two general features. The flora is practically entirely 
composed of green Algze (except for the above-mentioned species of Nostoc). 
Diatoms are represented only by fragments of frustules, and there are very 
few even of these. The Plankton character of the whole flora is also a point 
of interest, and indicates that it may have arisen in part by spores of 
Plankton-forms being carried by the wind on to the surface of the snow. 
This probably applies to all snow floras. 
C. Rep Snow $. 
The three samples (Nos. 4—6) of red snow included in the collections from 
the South Orkneys were all of them very poor in algal forms, showing that 
* V. В. Wittrock, “Om snóns och isens Flora, etc.," in А. Е. Nordenskiöld, ‘ Studier och 
forskningar, etc.’ (1883), pl. 3. fig. 2. 
+ Lagerheim, in Ber. Deut. Bot. Ges. x. 1892, pl. 28. fig. 1. Ithaving been suggested to 
me that the cells above described might be cysts of Rotifers, Г sent some material of yellow 
snow to Mr. James Murray, who very kindly informs me that the cells in question are quite 
unknown to him and not Rotifers. On the same authority I am able to state that the yellow 
snow includes yellow cysts (100-150 н) of Bdelloid Rotifers and a species of Collembola. 
{ Tufts of short threads, richly branched in an arborescent manner and composed of 
spindle-shaped cells, 1 р or less in diameter. Cells thickest at a point about two-thirds of 
their length from the base; from this point they taper gradually towards the base and 
rapidly towards the apex of cach cell. 
$ So many accounts of red snow have already been published that a general consideration 
seemed unnecessary, and the following account deals solely with the components of the 
samples of red snow from the South Orkneys. The most important contributions on the 
subject of red snow are :—V. В. Wittrock, “ Om snóns och isens flora,” etc., in Nordenshiüld, 
‹ Studier och forskningar’ (1883), рр. 65-123 & pl.3; Lagerheim, “ Bidrag 01 kännedomen 
om snüfloran i Гей Lappmark," in Bot. Notiser, 1883; Lagerheim, “ Die Schneeflora des 
Pichincha,” in Ber. Deutsch. Bot. Ges. x. 1892, pp. 517-534, pl. 28; Lagerheim, “ Ein 
Beitrag zur Schneeflora Spitzbergens,” in Nuova Notarisia, 1894; Chodat, “ Flore des 
neiges du col des Ecandies,” in Bull. de l'Herb. Boiss, iv. 1896, pp. 881 ef seg. & pl. 9; 
Chodat, * Algues vertes de la Suisse, 1902, pp. 95, 96. 
