HOIV ANIMALS ARE DISTRIBUTED OI^ER THE IVORLD 323 



ponds, swamps, pastures, woods, etc. Then search 

 carefully for the haunts of certain kinds of animals which 

 are known to occur in the mapped region, and mark them 

 on the map. It will soon be found that the different 

 kinds of animals are more or less limited to certain parts 

 of the region. Attempt may next be made to find out 

 why. Are there barriers .'' If so, of what nature '> They 

 cannot well be barriers of temperature or climate, unless 

 a mountain is included in the region, but may be con- 

 cerned with food, suitable hiding-places, proximity to 

 man, necessity of water for breeding in, etc. This is a 

 study, all of which must be made in the field, and where 

 much ingenuity in observing and reasoning must be used. 

 For a reference-book on the subject of this chapter 

 see Heilprin's the "Distribution of Animals," or Bed- 

 dard's "Zoo-geography." 



