OF MAMMALIA, ' 607 



elephants, several species of rhinoceros, hippopotamus, hyaenas and lions. 

 Mixed up with these in a remarkable manner are the remains of 

 northern forms like the wolverene, arctic fox, northern vole and reindeer. 



From this it follows that the past history of the Holarctic region is to 

 , a large extent an epitome of the faunas found in the other several regions 

 (leaving out of consideration the Sonoran). In early Oligocene of Europe 

 we find the lemurs and civets, now so characteristic of the Madagascar 

 region, and later on in the Pliocene and Pleistocene, the fauna with its 

 early aard-varks, elephants, hippopotamuses, and other early ungulates 

 approximated to the present-day fauna of Ethiopia and to the present 

 and early past of the Oriental. As most of those occur in the Miocene of 

 India, it is probable that they migrated thence to Europe, either directly 

 or through northern Africa. 



The resemblances in the faunas of North America and northern 

 Eurasia are usually explained as being due to a land-connection across 

 Behring sea. Tor which there is much evidence. This served to cause an 

 approximation in faunas between the northern parts, leaving the Sonoran 

 region and the Mediterranean district more or less distinct from each 

 other. 



5. Sonoran Region. — This, comprising practically the 

 United States of America, has been constituted as a separate 

 region mainly because it is a transition zone between Hol- 

 arctic and Neogoea, though it has some peculiar types of 

 its own. Of Neogoean types, we may note the armadillos, 

 opossums, peccaries and some Procyonidce^ whilst the skunks 

 and other Mustelidce^ the marmots and the pouched rats, 

 form Holarctic types. The most typical family of the 

 region is the American prongbuck (Antilocafra) which 

 has deciduous horns. This species also extends partly 

 into Canada. 



We may add here the names of some of the most char- 

 acteristic mammals found at the present day in the regions 

 of Arctogoea : — 



[Table. 



