H. JONSSON : MARINE ALGAL VEGETATION 69 



to the definition here employed. The Siberian Sea, however, 

 comes nearest to it. From here 23 species are known (14), of 

 which 9 (39%) are arctic, 11 (48%) subarctic and 3 (13%) boreal- 

 arctic. This district is at the boundary between arctic and sub- 

 arctic. Regarded superficially it may appear strange that none of 

 the districts are arctic, but on closer inspection this is easily under- 

 stood, the reason being that some of the districts (14) are too large 

 and consequently acquire a mixed character. In this respect I shall 

 merely point out, for instance, that both Spitzbergen and East 

 Greenland (and probably West Greenland) ought to be divided into 

 two districts. 



As already mentioned, none of the districts recorded in Table 6 

 is arctic. East Greenland, Spitzbergen and West Greenland have almost 

 the same percentage as regards the arctic species (Table 6), and as 

 this percentage is rather high in proportion to that of the boreal 

 species, these districts could be termed arctic-subarctic, in contra- 

 distinction to E. Iceland where the arctic percentage is four times 

 less than the percentage of the boreal species. The boreal districts 

 recorded here (Table 6, p. 70) should, strictly speaking, be called 

 cold-boreal. 



If we call the first three groups (in Table 6) A and the three 

 last B the percentages will be as follows: — 



E. Greenl Spitzb. W.Greenl. E. Icel. 



A 81 77 72 63 



B 19 23 28 37 



As the table shows, SW. Iceland agrees most closely with Fin- 

 mark, while S. Iceland and the Faeroes are nearly alike, as Borge- 

 sen (12, p. 804) also supposes. 



If we take Iceland as a whole, we get 143 species (red and 

 brown algae collectively), 10 (7 %) arctic, 21 (15 %) subarctic (sub- 

 division I), 29 (20 %) subarctic (subdivision II), 17 (12 %) boreal- 

 arctic, 56 (39 %) cold-boreal and 10 (7 %) warm-boreal. These figures 

 are almost the same as those given for Finmark (see Table 6) and 

 differ, essentially from the figures given for SW. Iceland, only 

 by the higher percentage of arctic and warm-boreal species. If, on 

 the other hand, we take the first three groups collectively and 

 the three last groups in a similar manner, we obtain the same 

 percentages as for SW. Iceland. On combining different parts of the 

 coast, as for instance, E. Iceland and N. Iceland, we get almost the 



Finm. 



SW. Icel 



S. Icel 



Fter. 



Norrtl 



46 



42 



30 



29 



27 



54 



58 



70 



71 



73 



