COLLECTED IN THE SOUTH ORKNEYS, 329 
Samples 1 and 3 (yellow snow !), abundant, 
Tt is probable that Pleurococeus vulgaris, Menegh. B coherens, Wittr. (“Om 
snöns och isens flora," loc. cit.), in part belongs to this species. Wittrock’s 
fig. 17 (on pl. 3) strongly recalls a patch of Protoderma Brownii. 
A full consideration of this species will be found on pp. 301-302. In 
sample 16 a very similar form was found growing on Prasiola crispa ; the 
cells (diam. 5-7 ш), however, lacked fat, and the cell-walls were not nearly so 
gelatinous. 
21. ЕВЕМОЗРНЕВА VIRIDIS, De Bary, Сопу. p. 56, t. viii. figs, 26-27 : 
Rabenhorst, FL Europ. Alg. iii. 1868, р. 24. 
"ample 11. 
Average diameter of cells =50 p. 
ULOTRICHACE;E, 
25. ULOTHRIX SUBTILIS, А72, Spee, Alg. p. 345 ; Tub. Phye, її. t. 85; 
Rabenhorst, FI. Еитор. Alg. iii. 1868, р. 265. 
Samples 1 and 8 (yellow snow !), rather rare. 
CH.ETOPHORACE.E. 
26. RAPHIDONEMA NIVALE, Lagerh. in Ber. Deutsch. Bot. Ges. x. 1832, p. 523, 
pl. 28. figs. 15-21. (РІ. 10. figs. 32, 33.) 
Samples 1-3 (yellow snow !), rather rare; 4-6 (red snow 1), rather 
common. 
Many of the filaments were narrower than Lagerheim's form ; diam, of 
cells =2-4 ш. See also рр. 317, 318, and 320. 
(EDOGONIACE®. 
27. CEDOGONIUM sp. 
Samples 1 and 3 (yellow snow !), isolated. 
Diam. of cells =20 ш; length of cells = 56-65 р; cells with numerous 
caps. 
28. ŒDOGONIUM sp. 
Sample 4 (red snow !), isolated. 
Diam. of cells =8 ш; cells about three times as long as their diameter. 
PRASIOLACEZE. 
29. PnasroLA СКІЅРА (Lightf), Ag. Sp. р. 416; Айг. Tub. Phye. v. t. 40. 
fig. 6. 
Samples 8, 9, 11, 12, and 16, abundant ; numerous early stages in sample 16. 
This form is already well known as occurring in Antarctic regions. It 
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