... 1 Texas) N. of Pennsylvania Boreal America 2 E. and N. of N. America 4 Alaska to Utah 1 Arizona and Texas to Mexico 1 Western, Cen., & Southern States 2 S. Eastern States 6 Palearctic Mexico Mexico Palæarc., Columb. (mig.) Boreal America and E. side of Palearctic Rocky Mountains 1 Mouth of Yellowstone River 1 High central plains to E. States Palæarc., Mexico, Andes (Pyrocephalus Mexico to Ecuador Neotropical 7 The whole region 96. Empidonax Mexico to Ecuador COLUMBE. COLUMBIDE. 121. Columba 122. Ectopistes 123. Melopelia 124. Zenaidura 125. Chæmepelia 1 S. and S. E. States VOL II-11 Neotropical 3 W. and Central States to Canada All regs. but Australian E. coast to Cen. plains, Canada 1 1 and British Columbia W. and S. Central States 1 All United States to Canada 1 California and S. E. States Neotropical CHAPTER XVI. SUMMARY OF THE PAST CHANGES AND GENERAL RELATIONS OF THE SEVERAL REGIONS. HAVING now closed our survey of the animal life of the whole earth-a survey which has necessarily been encumbered with a multiplicity of detail-we proceed to summarize the general conclusions at which we have arrived, with regard to the past history and mutual relations of the great regions into which we have divided the land surface of the globe. All the paleontological, no less than the geological and physical evidence, at present available, points to the great land masses of the Northern Hemisphere as being of immense antiquity, and as the area in which the higher forms of life were developed. In going back through the long series of the Tertiary formations, in Europe, Asia, and North America, we find a continuous succession of vertebrate forms, including all the highest types now existing or that have existed on the earth. These extinct animals comprise ancestors or forerunners of all the chief forms now living in the Northern Hemisphere; and as we go back farther and farther into the past, we meet with ancestral forms of those types also, which are now either confined to, or specially characteristic of, the land masses of the Southern Hemisphere. Not only do we find that elephants, and rhinoceroses, and hippopotami, were once far more abundant in Europe than they are now in the tropics, but we also find that the apes of West Africa and Malaya, the lemurs of Madagascar, the Edentata of Africa and South America, and the |