CHAPTER XV 

 GEOGRAPHICAL DISTRIBUTION 



Is not the biological laboratory which leaves out the ocean and the 

 mountains and meadows a monstrous absurdity? Was not the greatest 

 scientific generalization of your times reached independently by two 

 men who were eminent in their familiarity with living beings in their 

 homes? HUXLEY. 



UNDER the head of "Geographical Distribution' we con- 

 sider the facts of the diffusion of organisms over the surface 

 of the earth, and the laws by which this diffusion is governed. 



The geographical distribution of animals is often known as 

 " zoogeography. " In physical geography we may prepare 

 maps of the earth which shall bring into prominence the 

 physical features of its surface. Such maps would show here 

 a sea, here a plateau, here a range of mountains, there a desert, 

 a prairie, a peninsula, or an island. In political geography the 

 maps show the physical features of the earth, as related to the 

 states or powers which claim the allegiance of the people. In 

 zoogeography the realms of the earth are considered in relation 

 to the types or species of animals which inhabit them. 



Thus a series of maps of the United States could be drawn 

 which would show the gradual disappearance of the buffalo 

 before the attacks of man. Another might be drawn which 

 would show the present or past distribution of the polar bear, 

 black bear, and grizzly. Still another might show the original 

 range of the wild hares or rabbits of the United States, the 

 white rabbit of the Northeast, the cottontail of the East and 

 South, the jack rabbit of the plains, the snowshoe rabbit of 

 the Columbia River, the tall jack rabbit of California, the marsh- 

 hare of the South and the waterhare of the canebrakes, and 

 that of all their relatives. Such a map is very instructive, and 

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