Comparison of the Arctic and Antarctic Marine Floras. 89 



to how sufficient light could have been present at the poles to permit 

 of the luxuriant vegetation that once flourished in these regions. The 

 explanation that appears to me the most satisfactory is the one which 

 attributes these conditions to the very much greater size of the sun in 

 the early stages of the earth's history an idea first introduced into 

 geological speculations by Blandet {Bull. Soc. Geol. de France, ser. 2, 

 t. 25, p. 777, 1867-8), who likewise discussed the relations of Arctic 

 and Antarctic faunas together with the greater amount of aqueous 

 vapour in the atmosphere and the greater mass of the atmosphere.' 

 Dr. Murray holds that the pelagic Algae, Radiolaria, and Foraminifera 

 are probably the slightly modified descendants of a very ancient 

 universal pelagic fauna and flora. It is quite plain that the conditions 

 of environment of the pelagic flora are not such as to produce much 

 variation on any theory, and accordingly, though the mass of the 

 pelagic Algae enormously exceeds that of the littoral Algae, it consists, 

 so far as we know, of few species compared with the much-varied 

 littoral flora in fact, the discrepancy is so great as to hardly admit of 

 comparison at all. Similarly, zoologists have found that the mass of 

 individuals in the pelagic fauna probably greatly exceeds that of other 

 marine faunas, and that the species are few when compared with the 

 organisms of the shore and shallow water. Nearly all the fossil Algae 

 of the early Tertiary and the Secondary rocks, and the single form 

 known from the Devonian, are of a type found at the present time 

 within the Tropics, and with very few exceptions confined to the warmer 

 seas. They owe their preservation for the most part to their being 

 calcareous, which fits into the fact of their coming from warm seas 

 (see p. 75). Of course, we must assume that other Algae existed, and 

 their remains have been lost through their not being incrusted, &c. ; 

 but yet the argument has some weight. 



If, then, we test Dr. Murray's theory by an examination and 

 comparison of the Arctic and Antarctic marine floras, we would begin 

 by expecting a stronger agreement between the plankton floras than 

 between the littoral floras of these regions from the known stable 

 character of the former, and the varied and variable character of the 

 latter. In the following comparison there is, therefore, less agreement 

 to be expected than from a comparison of the total plankton and 

 littoral floras. 



In order to make the comparison we have taken Kjellman's Alga of 

 the Arctic Sea as representing the one part ; and for the Antarctic we have 

 compiled a list. The region includes Cape Horn and the Falkland 

 Islands, Marion, Kerguelen and Heard Islands, and Lord Auckland 



