438 



NATURAL SCIENCE. 



June, 



Palaearctic and Nearctic regions respectively are not found in the 

 other, indicates a fundamental diversity that renders their union into 

 one region quite inadmissible. 



We will now tabulate the birds, in which the amount of diversity 

 is much larger as regards genera, and equally as large as regards 

 families : — 



Land Birds of the Pal^arctic and Nearctic Regions. 



