98 CIRCUMSTANCES FAVORABLE TO THE 



isolated areas have been in some respects highly favorable 

 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 victor- 

 ious over many competitors, will be those that will spread 

 most widely, and will give rise to the greatest 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, under- 

 stand some facts which will be again alluded to in our 

 chapter on Geographical Distribution; for instance, the 

 fact of the productions of the smaller continent of Austra- 

 lia now yielding before those of the larger Europaeo- Asiatic 

 area. Thus, also, it is that continental productions have 

 everywhere become so largely naturalized 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 Maderia, according to Oswald Heer, resembles 

 to a certain extent the extinct tertiary flora of Europe. 

 All fresh water basins, taken together, make a small area 

 compared with that of the sea or of the land. Con- 

 sequently, 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, con- 

 nect to a certain extent orders at present widely sundered 

 in the natural scale. These anomalous forms may be 

 called living fossils; they have endured to the present day, 

 from having inhabited a confined area, and from having 

 been exposed to less varied, and therefore less severe, com- 

 petition. 



To sum up, as far as the extreme intricacy of the subject 

 permits, the circumstances favorable and unfavorable for 

 the production of new species through natural selection. 

 I conclude that for terrestrial productions a large conti- 



