THE GEOGRAPHIC DISTRIBUTION OF LIFE IN NORTH 
AMERICA. 
WITH SPECIAL REFERENCE TO THE MAMMALIA.* 
By C. HART MERRIAM, M. D. 
Nine years ago the Biological Society listened to an address from its 
distinguished retiring president, Prof. Gill, on “The Principles of 
Zo0- geography,” or the science of the geographical distribution of ani- 
mals.t Prof. Gill assembled the oceans of the globe as well as the land 
areas into primary divisions or “ zodlogical realms,” of which he recog- 
nized nine for the land and five for the sea. It is not my purpose to 
discuss the zodlogical regions of the whole world, but to lay before you 
some of the facts concerned in the distribution of terrestrial animals 
and plants in North America with special reference to the number and 
boundaries of the subregions and minor life areas, and to touch upon 
the causes that have operated in their production. 
No phenomenon in the whole realm of nature forced itself earlier 
upon the notice of man than certain facts of geographic distribution. 
The daily search for food, the first and principal occupation of savage 
man, directed his attention to the unequal distribution of animals and 
plants. He not only noticed that certain kinds were found in rivers, 
ponds, or the sea, and others on land, and that some terrestrial kinds 
were never seen except in forests, while others were as exclusively 
restricted to open prairies, but he observed further, when his exeur- 
sions were extended to more distant localities or from the valleys and 
plains to the summits of neighboring mountains, that unfamiliar fruits 
and insects and birds and mammals were met with, while those he 
formerly knew disappeared. 
*Annual Presidential Address, delivered at the tweifth anniversary meeting of the 
Bivlogical Society of Washington, February 6, 1892. (From the Proc. Biolog. Soc., 
Washington, vol. vil, pp. 1-64.) 
t Proc. Biolog. Soc., Washington, 1884, vol. 1, pp-1-39. 
365 
