GEOGRAPHICAL DISTRIBUTION 321 



of the country, he sees so many familiar natural objects that he can 

 hardly help fancying he is close to his home. He finds the woods and 

 fields tenanted by tits, hedge sparrows, wrens, wagtails, larks, red- 

 breasts, thrushes, buntings, and house sparrows; some absolutely 

 identical with our own feathered friends, others so closely resembling 

 them that it requires a practised ornithologist to tell the difference. 

 . . . There are also, of course, many birds and insects which are 

 quite new and peculiar, but these are by no means so numerous or 

 conspicuous as to remove the general impression of a wonderful 

 resemblance between the productions of such remote islands as Britain 

 and Yezo." (ISLAND LIFE.) 



A journey to the southward from Britain or Japan or 

 Illinois, or any point within the holarctlc realm, would show 

 the successive changes in the character of life though gradual, 

 to be still more rapid. The barrier of frost which keeps the 

 fauna of the tropics from encroaching on the northern regions 

 once crossed, we come to the multitude of animals whose life 

 depends on sunshine, the characteristic forms of the neo- 

 tropical realm. 



The neotropical, or South American realm, includes South 

 America, the West Indies, the hot coast lands (Tierra Caliente) 

 of Mexico, and those parts of Florida and Texas where frost 

 does not occur. Its boundaries through Mexico are not sharply 

 denned, and there is much overlapping of the north temperate 

 realm along its northern limit. Its birds, especially, range 

 widely through the United States in the summer migrations, and 

 a large part of them find in the North their breeding home. 

 Southward, the broad barrier of the two oceans keeps the 

 South American fauna very distinct from that of Australia or 

 Africa. The neotropical fauna is the richest of all in species. 

 The great forests of the Amazon are the treasure houses of the 

 naturalists. Characteristic types among the larger animals 

 are the broad-nosed (platyrrhine) monkeys, which in many 

 ways are distinct from the monkeys and apes of the Old World. 

 In many of them the tip of the tail is highly specialized and is 

 used as a hand. The Edentates (armadillos, ant-eaters, etc.) 

 are characteristically South American, and there are many 

 peculiar types of birds, reptiles, fishes, and insects. 



The Indo-African or paleotropical realm corresponds to 

 the neotropical realm in position. It includes the great part 



