554 LAND MAMMALS IN THE WESTERN HEMISPHERE 



Eocene ; in the Oligocene were added the mustelines and cats ; 

 the raccoons branched off from the dogs in the lower Miocene, 

 as did the bears in the upper Miocene. Finally, the hyenas 

 appeared in the lower Pliocene, seemingly derived from the 

 viverrines. The dogs passed through the greater part of 

 their development in North America, where, during the Oli- 

 gocene and Miocene, they were very abundant and varied, 

 while at the same time they were comparatively rare in Europe 

 and belonged chiefly to the phylum of the fbear-dogs. On the 

 other hand, the remaining four families are of Old World 

 origin, the bears and mustelines migrating to America, while 

 the viverrines and hyenas did not. 



Suborder tCREODONTA. fPRiMiTivs Flesh-eaters 



This group long preceded the Fissipedia in time, for they 

 began their recorded history in the Paleocene and became 

 extinct in the Oligocene. Through one family, the f^iacidae, 

 the fcreodonts were broadly connected with the fissipedes, 

 and it seems probable that that family was the ancestral 

 stock from which all the fissipede famihes were derived. The 

 other fcreodont families died out without leaving descendants. 



There is some difference of practice as to the number of 

 families to be admitted; the table contains those listed in 

 Professor Osborn's book and also adopted by Dr. Schlosser. 

 I should prefer a somewhat larger number of family groups, 

 but the matter is one of secondary importance. Many genera 

 are omitted. 



I. fOXYCLjENIDiB. 



^Oxyclmnus, Paleoc. 1[Deltatherium, do. 



II. fARCTOCTONID^. 



\Cloenodon, Paleoc. \Anacodon, low. Eoc. 



III. tMESONYCHID.«i. 



\Triisodon, Paleoc. ^Dissacv^, do. fPachycena, low. Eoc. ^Mes- 

 onyx, mid. Eoc. ^Dromocyon, do. t Harpagolestes, mid. and up. 

 Eoc. 



