xiv DISTRIBUTION 593 



Pheasants, Robins, Magpies, and many other Birds are highly 

 characteristic, and many species of Deer, Oxen, and Antelopes, 

 Rodents, Passerines and other Birds, Reptiles, Amphibia including 

 Proteus and fresh-water Fishes, are endemic. 



The Palsearctic region includes, as we have seen, nearly all the 

 northern portion of the eastern hemisphere ; the corresponding 

 part of the western hemisphere, viz., North America, with Green- 

 land, constitutes the Nearctic Region. It also is bounded by 

 the ocean on its northern, eastern, and western sides, while in the 

 south an ill-defined tract of country, passing between Cape San 

 Lucas on the west and the Rio Grande del Norte on the east, 

 separates it from the Neotropical region. 



The Nearctic differs from the Palsearctic region in the possession 

 of several characteristic Mammals, such as Opossums (Didelphyidce), 

 the Skunk, Racoon, etc. ; many Birds, such as the Blue-jays, 

 and Turkey-buzzards, etc. ; Reptiles, such as Rattlesnakes and 

 Iguanas ; Amphibia, including the Axolotl, Necturus, Siren, and 

 other large Urodeles ; and numerous fresh-water Fishes, in- 

 cluding Amia, Lepidosteus, Polyodon, and Scaphirhynchus. Only 

 three entire families are endemic, two of Rodents, and one of 

 Passerines. 



On the other hand, the resemblances between the two northern 

 regions are very close. Both possess Wild Cats, Hyenas, Foxes, 

 Weasels, Bears, Elk, Deer, Wild Oxen, Beavers, Voles, Squirrels, 

 Marmots, and Hares, the species of the one region being all closely 

 allied to, and sometimes identical with, those of the other. Thrushes, 

 Wrens, Tits, and Finches are also common to the two regions, and, 

 generally speaking, the differences between them are, as we shall see, 

 nothing like so striking as those between either of them and the 

 region or regions bounding it to the south. Hence the Palsearctic 

 and Nearctic regions are sometimes grouped together as a single 

 Holarctic Region. 



In the southern regions the characteristic features are much 

 more striking. The Ethiopian Region is constituted by the 

 whole of Africa and Arabia south of the tropic of Cancer, together 

 with Madagascar, Mauritius, Bourbon, Rodriguez, and the 

 Seychelles. The region is bounded by sea on the west, south, 

 <md east, but on the north it is perfectly continuous with the 

 Palaearctic region, and it certainly seems a very remarkable fact, 

 until we remember what an impassable barrier is afforded by a 

 sandy desert of great extent, that there should be more difference 

 between the faunas of northern and central Africa than between 

 those of England and Japan, or of Alaska and Florida. 



Among the animals most characteristic of the Ethiopian region 

 and not found elsewhere are the Gorilla, the Chimpanzee, several 



VOL. II Q Q 



