424 THE BIOCOSMOS HISTORICAL. 



tor. This ancestor was the continent of South 

 America from which these different islands 

 had been originally separated, and been made 

 to constitute an entirety together (the archi- 

 pelago) ; then the archipelago was divided up 

 into a number of large and small islands, and 

 even some smallest ones. Says Darwin in his 

 Journal: "This archipelago consists of ten 

 principle islands of which five exceed the oth- 

 ers in size. ' : It is evident that the earth itself 

 presented variations which might be classified 

 after the model of Natural History as family 

 (the original continent), as genus (the archi- 

 pelago as a whole), and as species (the several 

 sorts of islands), each of which finally had its 

 individuals. But the striking fact was that all 

 these gradations were separated from one 

 another, insulated we may say; and they all 

 -family, genus, species, individuals had 

 their real counterparts before the eye. Thus 

 the territory itself furnished the framework 

 and suggested externally the order and evo- 

 lution of living things there found. 



Again we shall cite Darwin's Journal: "By 

 far the most remarkable feature in the nat- 

 ural history of this archipelago is that the dif- 

 ferent islands to a considerable extent are in- 

 habited by a different set of beings," that is, 

 the life upon them varies. For instance, the 

 tortoises of the same species on different is- 



