ALLEN ON GEOGRAPHICAL DISTRIBUTION OF MAMMALS. 345 



Region" as mapped by Mr. Wallace,* Brazil, nearly all of Paraguay, 

 and Bolivia east of the Andes being included within this realm. 



Its characteristic genera include all of the American Quadrumanes 

 (families Cebidce and Mididcc,=Hapalidce of most authors), all the Ameri- 

 can Edentates, and nine-tenths of the American Marsupials. It is also 

 the home of nearly all the American Felidce, except the Lynxes. It also 

 has many peculiar genera of Glires and Chiroptera, while it almost alto- 

 gether lacks the characteristic forms of mammalian life found in the 

 northern temperate regions. Among the characteristic North American 

 types unrepresented in the American Tropical Realm are, among Car* 

 nivores, not only the Lynxes, but the true Wolves and Foxes, the Mar- 

 tens, Wolverenes, Badgers, and Bears ; among Ungulates, the Prong- 

 horn, the Bison, Mountain Sheep, and Mountain Goat, and several 

 important genera of the Cervidce ; among Rodents, the Spermophiles, 

 Marmots, Muskrat, Beaver, Pouched Eats, "Gophers" (Geomys and 

 Thomomys), the numerous species QfArvicola, etc., in short almost all of 

 the prominent and characteristic genera of the order except the almost 

 cosmopolitan genera Lepus and Sciurus; among Insectivores, all the 

 Moles and Shrews, except a few forms of the latter, which extend over 

 most of the Central American Region. 



The American Tropical Realm is divisible into three regions, the 

 Autillean, the Central American, and the Brazilian. The Antillean Re- 

 gion includes only the West Indies and the southern extremity of Flor- 

 ida. The Central American Region embraces Mexico (exclusive of the 

 elevated tablelands), the whole of Central America, and the extreme 

 northern parts of South America (Venezuela north of the Orinoco Basin, 

 Northern and Western New Granada, and most or all of that portion of 

 Ecuador west of the Andes). The Brazilian Region comprises all the 

 intertropical parts of South America not embraced in the Central Amer- 

 ican Region, including the whole area east of the Andes southward to 

 the boundary already given. 



Central American Eegion. Of the genera occurring in the Central 

 American Region (see subjoined table), only about one-ninth can be 

 considered as peculiar to the region ; about one-sixth are either sub- 

 cosmopolitan or tropicopolitau ; about three-fifths range also over the 

 Brazilian Region, and a few over nearly all of South America ; about one- 

 half extend far into North America, among which are several that are 

 also common to the greater part of the North Temperate Realm, while 

 about one-eleventh are also found over most of both North America 

 and South America. Aside from the few peculiar genera, the fauna is 

 composed largely of genera common also to the Brazilian Region, which 

 find their northern limit of distribution within the Central American 

 Region, plus a very large proportion that extend southward from the 

 North American Temperate Region, and which find their southern limit 

 of distribution within the region under consideration. . Its distinctive 



* Geogr. Dist. Anim., vol. ii> map facing page 3. 

 Bull. iv. No. 2 3 



