272 



VERTEBllATA 



these organs are comparatively short. Rabbits intro- 

 duced into countries where their natural enemies, hawks, 

 owls, eagles, and carnivorous mammals are not sufficiently 

 abundant to keep them in check, have become great pests. 

 In Australia they devoured the grass to such an extent 



FIG. 3U8. Photograph, of the elephant showing the exte 

 the trunk. 



al nares at the end of 



that thousands of sheep starved to death. Fifteen million 

 skins were exported from New South Wales in one year. 

 In some places the government has erected fences of wire 

 netting to keep the pests from destroying the crops. Since 

 the killing off of the coyotes and wolves in western United 

 States, the jack rabbits have increased enormously, so 



