XVJII.] DISTKIBUTION. 227 



and botany sliow extensive contiguous areas to be usually 

 inhabited by similar tliougli different species^ even wlieu 

 the climates of the two are very unlike. 



lu the next chapter I intend to consider how far the 

 facts of morphology can be referred to the principle of the 

 adaptation of every part of an organism to all the rest. 



Q 2 



