CHAP. IV.] 



ZOOLOGICAL EEGIONS. 



81 



arisen ; and it is hoped that these divisions will prove as satis- 

 factory and useful to naturalists in general as they have been to 

 the author. Of course, in a detailed study of any region much 

 more minute sub-division may be required; but even in that 

 case it is believed that the sub-regions here adopted, will be 

 found, with slight modifications, permanently available for ex- 

 hibiting general results. 



I give here a table showing the proportionate richness and 

 speciality of each region as determined by its families of verte- 

 brates and genera of mammalia and birds ; and also a general 

 table of the regions and sub-regions, arranged in the order that 

 seems best to show their mutual relations. 



Comparative Richness of the Six Regions. 



Table of Regions and Sub-regions. 



