I 111 ri;'.|:l.l M> ..1 \NI\l;. (10 I'l AN I 1. 1KB. 18 



discoloured by di.itoms, and I am not aware that other recent expeditions have recorded 

 this or.-urrriH-e ; but hi \V S. I'.ru,-.-, in the cruise of tin- llal#nti in 1892-93 between 



md 63* S., off Louis Philippe Land, frequently remarked that the sea was olive- 

 green <>r iilivi--l>ro\vii from thin cause, and that the moat usual species in these dis- 

 "l'iuiv.1 j'.irts was Core th ran cnojiliilum. This phenomenon is of much commoner 

 in viirri-iire in Arctic seas. 1 Plankton collections well within Antarctic seas and ovi-r a 

 wide area are largely continrd to the collections of the Si'olia, which fortunately was 

 able to traverse some 10,000 miles of unexplored south polar waters. The other r < nt 

 expeditions, Discovery, Antarctic, Gauss, Franc/iis, and Nimrod, did cumparativi -ly 

 little in.irine exploration within truly polur waters. The Jirlyica's results in this dt- 

 |Mitment should, however, be of great interest, and will be supplemented by those of 

 the Poun/tioi Pan?, while the \'<il<li,-i-i'a collections, though in more or less extra-polar 

 waters, have im|>ortant relation to Antarctic plankton. A detailed report and discussion 

 <>f tin- Scotia' plankton in in process of completion. 



While freshwater algae ap|>ear to be comparatively abundant, they are not nearly 

 so plentiful as in north polar r.-._'i,.ns. In the collections which I made at the South 

 Orkm-ys, lr Fritsch has found 68 species (of which 5 are new): most are uni- 

 cellular and colonial. 1 With the exception of the Belgica, the Southern Cross, the 

 Discovery, and the Nimrod, other expeditions have not yet published their results 

 in this branch of botany. A number of forms, however, have been recorded from 

 Iv rgueleu and South Georgia. 



Among the South Orkney collections very few reproductive stages were found even 

 in material collected about midsummer, and Dr Fritsch believes that many species only 

 reproduce during very limited periods under specially favourable conditions. The 

 rarity of diatoms and infrequence of desmids in this freshwater flora are noteworthy 

 None of the new forms of diatoms in either the Discovery or Nimrod collections occur 

 at the South Orkneys. 



Red and yellow snow occur at the South Orkneys, though neither is abundant. Red 

 snow bos been recorded from Arctic regions, as well as other parts of Antarctic regions, 

 including Graham Land and Victoria Land : it is also recorded from extra-polar regions. 

 Yellow snow is much rarer, and I am not aware that other Antarctic expeditions came 

 across it Dr Fritsch has reported in considerable detail on these coloured snows (loc. cit.), 

 and he finds that yellow snow is due to an association of 18 species of alga; and 2 of fungi ; 

 most of the algse are green forms, but few diatoms occur. The whole of this flora has a 

 plankton character, and Dr Fritsch suggests that this and other snow floras may have 

 arisen by wind carriage of plankton forms to the snow surface. Most of the constituent 

 members of this flora have a quantity of fat in their cell contents, in which yellow 

 pigment occurs. This fact seems to be an adaptation to the severity of the habitat 



1 u On the Nature of the Discoloration of the Arctic Sew," Robert Brown, TV-iiu. JioL Soe. Edin~, it. p. 844 

 * Bee this volume, pp. 95-134, and " Freih water Alga- collected in the South Orkneys," Journ. Linn. Soe. Land 

 L, 1918, pi 



