12 BOTANICAL RESULTS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



among the Scotia algae was the new species Phyllogigas simulans. This was first 

 described (loc. cit.) by Mr and Mrs Gepp from material I collected at the South Orkneys. 

 Since then it has also been found at Graham Land and South Georgia by Dr Skottsberg, 

 and another species (P. grandifolia) has been recorded by the Discovery from Victoria 

 Land. It is a genus whose species have some similarities in habit to that of the " kelp," 

 although it is anything but abundant. 



Our knowledge of Antarctic multicellular algse is practically confined to the Graham 

 and Victoria Land regions ; and though most of the collections are now published, it 

 would be rash to draw any deductions of a distributional nature ; for while the Graham 

 Land region has been the more carefully explored of the two, neither can be said to be 

 known thoroughly as regards its algse. Some 40 species are at present known from 

 Antarctic seas, of which about 75 per cent, occur at Graham Land, and about 40 per 

 cent, at Victoria Laud. Dr Skottsberg has discussed in various papers (see Biblio- 

 graphy) the distribution of these algse as far as is possible, and he finds that no facts 

 in this realm of botany support the idea of bipolarity. 



Only one species of freshwater alga (other than unicellular and colonial algse) is so 

 far known, viz. the cosmopolitan Prasiola crispa, Ag., which is recorded from both 

 Graham Land and the South Orkneys. 1 In the latter place it was to be found in summer 

 and autumn in several small gulleys where a quantity of melting snow above assured a 

 continual supply of moisture. 



Unicellular algse naturally form the vast preponderance of the botanical treasures 

 of the Antarctic regions. When once the regions of ice. are approached, between 

 50 S. and 60 8., the plankton entirely changes its character; crustaceans, and in 

 fact all animals, then become rare, and give place to increasing numbers of diatoms 

 until, in the midst of the ice, the diatoms occur in such prodigious quantities that 

 five minutes' haul of the tow-net (No. 20 miller's gauze) produces as much as a 

 pint of gelatinous residue almost wholly diatomaceous. The fact that such a net, 

 used about thrice daily on the average, ceases to be serviceable after about a week or 

 ten days' use, owing to the clogging of the apertures in the silk, will give an idea to 

 anyone accustomed to plankton work of the wealth of diatomaceous life in these seas. 

 The species are not very varied, but a large proportion of them bear spines and long 

 arms, while simple forms are comparatively rare. Peridineans occur, but only rarely. 

 The phytoplankton on the whole seems to favour deep water, for in the shallow water 

 about the South Orkneys it was much scarcer. In winter the greater part is apparently 

 frozen into the ice, for 1 failed to get any appreciable quantities from the water on the 

 occasions when I bored the floe with this object in view. The first-formed pancake ice 

 is always yellow, and the lower layers of the floe as revealed in the spring upheaval are 

 uniformly discoloured by a layer of diatomaceous ice. 



In no part of the Antarctic seas visited by the Scotia did I observe the open water 



1 Some authorities recognise Prasiola antarctica, Kiitz, in addition to P. crispa, in Antarctic lands. See " Fresh- 

 water Alg;e," W. and G. S. West, Brit. Antarct. Exped. (1907-09), 1911, vol. i., and F. E. Fritsch, p. 128 of this volume. 



