Ill EXPEDITION OF THE " CHALLENGER " 75 



The results of the Antarctic exploration, as 

 stated by Dr. Hooker in the " Botany of the Ant- 

 arctic Voyage," and in a paper which he read 

 before the British Association in 1847, are of the 

 greatest importance in connection with these 

 views, and they are so clearly stated in the former 

 work, which is somewhat inaccessible, that I make 

 no apology for quoting them at length 



" The waters and the ice of the South Polar Ocean were alike 

 found to abound with microscopic vegetables belonging to the 

 order Diatomacece. Though much too small to be discernible 

 by the naked eye, they occurred in such countless myriads as 

 to stain the berg and the pack ice wherever they were washed by 

 the swell of the sea ; and, when enclosed in the congealing 

 surface of the water, they imparted to the brash and pancake 

 ice a pale ochreous colour. In the open ocean, northward of 

 the frozen zone, this order, though no doubt almost universally 

 present, generally eludes the search of the naturalist; except 

 when its species are congregated amongst that mucous scum 

 which is sometimes seen floating on the waves, and of whose 

 real nature we are ignorant ; or when the coloured contents of 

 the marine animals who feed on these Algse are examined. To 

 the south, however, of the belt of ice which encircles the globe, 

 between the parallels of 50 and 70 S., and in the waters com- 

 prised between that belt and the highest latitude ever attained by 

 man, this vegetation is very conspicuous, from the contrast 

 between its colour and the white snow and ice in which it is 

 imbedded. Insomuch, that in the eightieth degree, all the 

 surface ice carried along by -ihe currents, the sides of every 

 berg, and the base of the great Victoria Barrier itself, within 

 reach of the swell, were tinged brown, as if the polar waters 

 were charged with oxide of iron. 



"As the majority of these plants consist of very simple vege- 

 table cells, enclosed in indestructible silex (as other Algce are in 

 carbonate of lime), it is obvious that the death and decomposi- 



