DISTRIBUTION OF ANIMALS 



505 



land. Oceanic islands are characterized by a complete absence of mam- 

 mals and amphibians. On many such islands there is a decided tendency 

 toward the existence of wingless birds and insects. This has been 

 explained by the fact that flying forms would be hkely to be swept away 

 by winds and thus destroyed. 



20 40 60 80 100 120 140 160 180 



Fig. 310B. — The zoogeographical regions of the eastern hemisphere. 



New Zealand is an island which is peculiar in possessing some of the 

 faunal characteristics of a continent. There are only two native mam- 

 mals, a bat and a rat, both of small size. The birds of New Zealand have 

 been in the past and are now very characteristic. Among them are the 

 gigantic moas, now extinct, and the curious Apteryx, or kiwi, now becom- 

 ing very scarce. Among the reptiles is the peculiar Sphenodon (Fig. 

 264). The amphibians are represented by a single species of frog. 



