122 THE WANDERINGS OF ANIMALS [CH. 



Low Eocene of North America should prove to be 

 4 primitive Edentates,' and if Metachiromys of North 

 American Eocene were an armadillo, as has been 

 asserted and denied, then we might look for the 

 original home of the order in North America, whence 

 they spread into the south, leaving a blank in the 

 north. The north and south connexion became avail- 

 able in the Miocene, in time enough for the outburst 

 of the order in South America, but far too late for 

 Africa and Europe. 



Rodents. 



This vast order comprises almost 1000 recent 

 species and is, as an order, quite cosmopolitan ; 

 some of the families are already recognisable in the 

 Eocene. 



Hares, with the chief genus Lepus, date from 

 American Oligocene ; earliest occurrence in Eurasia 

 not until the Pliocene. Now on every continent ; 

 absent from Australia and all ancient islands. The 

 variable hare, which turns white in winter, ranges 

 from Greenland and Canada through Siberia and 

 Scandinavia, with the outlying centres of Ireland, 

 Scotland, Pyrenees, Alps, Caucasus and Japan. 



Squirrels, etc. are cosmopolitan excepting Aus- 

 tralasia, Madagascar and Antilles. Flying squirrels 

 have developed in India, northern Europe and Siberia, 

 and thence in the pine forests of North America. 



