138 WILLIS: THE FLORAS OF HILL TOPS. 



at different times, and that the older, and those with the 

 better mechanisms, have spread the most. Those most early 

 evolved would also perhaps find the forest less dense, and be 

 more easily able to get about. 



Mosi mountain countries show a fair number of endemic 

 forms, even if they be not confined to one mountain top, and 

 Ceylon has numerous endemic forms ranging over a greater 

 area in the mountains than those dealt with in this paper. 



The general conclusion, then, must be that isolation, as 

 isolation, favours the development of new forms, and that local 

 conditions have but little effect in developing, though they 

 may have much in determining the survival of these new 

 forms, and that consequently natural selection of infinitesimal 

 variations, on ecological grounds, is unlikely. It is more than 

 doubtful if any given species is specially adapted to the exact 

 local conditions in which it is found. 



