376 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



have beeu pressed a little to the southward by the extreme rigor of an 

 Arctic climate, but are still characteristic elements of all boreal faunas. 

 The very few truly tropicopolitan mammalia are either Chiroptera, or 

 marine, or at least aquatic, and have thus exceptional means of dis- 

 persal. 



The primary regions and their subdivisions, recognized in the preced- 

 ing pages, are enumerated in the subjoined schedule. 



1. — Primary divisions, or '''■Realms^K 



1. An Arctic, or North Circumpolar. 



II. A North Temperate, divided into two regions and eight prov- 

 inces. 



III. An American Tropical, with three regions. (Provinces not 



characterized.) 



IV. An Indo- African, with two regions and five provinces. 

 V. A South American Temperate, with two provinces. 



VI. An Australian, with three regions and two provinces. 

 VII. A Lemurian. 

 VIII. An Antarctic or South Circumpolar. 



2. — Secondary divisions, or ^^Begions^\ 



II. North Temperate Eealm : 1, American ; 2, Europeeo- Asiatic. 



III. American Tropical Realm : 1, Antillean ; 2, Central American ; 



3, Brazilian. 



IV. Indo- African Realm : 1, African ; 2, Indian. 



VI. Australian Realm : 1, Australian (Australia, Tasmania, and New 

 Gruinea); 2, Polynesian ; 3, New Zealand. 



3. — Divisions of third ranTc, or ^^ Provinees^K 



II, 1. American Region: a, Boreal*; &, Eastern; c, Middle; <^, Western. 

 II, 2. Europseo- Asiatic Region: a, European; h, Siberian; c, Mediter- 

 ranean ; d, Manchurian. 

 IV, 1. African Region : a, Eastern ; 6, Western ; c. Southern. 

 IV, 2. Indian Region : a, Continental ; &, Insular. 

 V. South American Temperate Realm : a, Andean ; ft, Pampean. 

 VI, 1. Australian Region : a, Australian; b, Papuan. 



* A " Boreal " province has not been distinctly recognized in the preceding pages as 

 a divisiou belonging to the same category as the other so-called or commonly recog- 

 nized provinces, and is not at all recognized in the table of distribution given at p. 

 339. It is nearly equivalent to what is there implied by "Cold Temperate". I hope 

 soon to be able, in a paper to be devoted especially to a consideration of the geograph- 

 ical distribution of North American mammals, to define and characterize it more defi- 

 nitely. 



