118 ORIGIN OF SPECIES 



nated. Each new form, also, as soon as it has been much 

 improved, will be able to spread over the open and continu- 

 ous area, and will thus come into competition with many- 

 other forms. Moreover, great areas, though now continuous, 

 will often, owing to former oscillations of level, have existed 

 in a broken condition; so that the good effects of isolation 

 will generally, to a certain extent, have concurred. Finally, 

 I conclude that, although small isolated areas have been in 

 some respects highly favourable for the production of new 

 species, yet that the course of modification will generally have 

 been more rapid on large areas ; and what is more important, 

 that the new forms produced on large areas, which already 

 have been victorious over many competitors, will be those 

 that will spread most widely, and will give rise to the great- 

 est number of new varieties and species. They will thus 

 play a more important part in the changing history of the 

 organic world. 



In accordance with this view, we can, perhaps, understand 

 some facts which will be again alluded to in our chapter on 

 Geographical Distribution; for instance, the fact of the pro- 

 ductions of the smaller continent of Australia now yielding 

 before those of the larger Europaeo-Asiatic area. Thus, also, 

 it is that continental productions have everywhere become so 

 largely naturalised on islands. On a small island, the race 

 for life will have been less severe, and there will have been 

 less modification and less extermination. Hence, we can 

 •understand how it is that the flora of Madeira, according to 

 Oswald Heer, resembles to a certain extent the extinct ter- 

 tiary flora of Europe. All fresh-water basins, taken together, 

 make a small area compared with that of the sea or of the 

 land. Consequently, the competition between fresh-water 

 productions will have been less severe than elsewhere; new 

 forms will have been then more slowly produced, and old 

 forms more slowly exterminated. And it is in fresh-water 

 basins that we find seven genera of Ganoid fishes, remnants 

 of a once preponderant order : and in fresh water we find 

 some of the most anomalous forms now known in the world 

 as the Ornithorhynchus and Lepidosiren, which, like fossils, 

 connect to a certain extent orders at present widely sundered 

 in the natural scale. These anomalous forms may be called 



