12 ON ALG.E FOUND DURING THE ARCTIC EXPEDITION. 



Synedra fulgens, Grev., 2, 11, 14, Thalassiosira Nordenskioldii, CL, 



28. 



2,8,9,10,11,12,13,14,28. 

 karatschatica, Grun., 13. Triceratium arcticum, Brightw,, 8, 



superba, Sm., 7, 11, 12, 28. 11, 12, 13, 14, 20, 28. 



tabulata, Ktz., 5, 25, 26. Tryblionella marginata, Sm., 13, 14. 



Summary. 



The seven species of the higher types, enumerated first, all 

 belong to the Olive-coloured series, and, with the exception of the 

 two species of Lamlnaria, are well-known European forms ; I could 

 not find any trace of a marine species belonging to the Eed series. 



The most complete list of Arctic Algae in a high northern lati- 

 tude is that of Spitzbergen, given by Professor J. G. Agardh, 

 comprehending 17 Olive and 20 Eed ; the sea in that quarter is 

 rich in species compared with the localities visited during the late 

 Expedition. The three marine Alga? of the Green series have a 

 very wide distribution in European and other seas ; and, with one 

 exception, the marine Algae noticed here occur also in the Spitz- 

 bergen sea. Of freshwater species there are representatives of 

 14 genera ; and most of them are also found in various parts of 

 Europe. The Diatomaceae represent 31 genera, and amount to 

 70 species so far as observed by me ; most of them are marine, 

 the freshwater species being few in number. The presence of 

 these minute organisms, with their exquisitely sculptured siliceous 

 investments, is a point of much interest in relation to the presence 

 of certain forms of animal life. T have repeatedly received 

 masses of such, resembling pieces of fat or of sodden bread, from 

 ice-floes in various parts of the Arctic sea ; and in the alimentary 

 canal of bivalve Mollusca from the same quarter preserved in 

 spirits, I have found abundance of marine Diatoms. 



Where these occur (and they are generally plentiful), this implies 

 the possible presence of animal life, the lower forms of which are 

 preyed upon by the higher ; and thus we have a very notable and 

 interesting chain of dependence. It is not, therefore, a matter for 

 surprise that 16 species of Bivalves were collected beyond 80° N. 

 by the naturalists of the Expedition. 



P. T. Cleve, in a communication to the Swedish Academy of 

 Sciences in 1873, states that the entire number of Diatoms found 

 in the Arctic sea is 181 ; the species already enumerated, exclu- 

 ding the 12 freshwater, amount to about one third. From the 

 same paper it would appear that those found near Spitzbergen are 

 far more numerous than those now recorded. 





