GEOGRAPHICAL DISTRIBUTION OF ORGANISMS. 403 



but with affinities connecting with several different lands. 

 The predominance of affinities will depend partly on 

 proximity and partly on the direction of winds and cur- 

 rents. Mammals (except bats) and amphibians are en- 

 tirely wanting (unless introduced by man) because these 

 are not apt to be drifted on logs, as are some reptiles. 



