218 ANNALS NEW YORK ACADEMY OF SCIENCES 



America until the Pliocene, llieir place being supplied uj) lu llial lime 

 by carnivorous marsupials. In Australia, their place is still taken by 

 carnivorous marsupials. In Africa, primitive Carnivora (ereodonta) 

 appear in the Oligocene, represented only by the extinct family of hyasno- 

 donts, all of them derivable from Eocene hyaenodonts of the Holarctic 

 region; but the contemporary Holarctic JFissipedia had not yet reached 

 Africa. 



The modern land Carnivora are divided into seven families, each rep- 

 resenting one or more broad phyla. The various divergent adaptations 

 of the phyla and secondary re-adaptations of subpliyla have brought 

 about an amount of convergence and parallelism which makes it difficult 

 to disentangle or to state accurately the true genetic relationship in any 

 tei-ms of classification. Some of the phyla are Holarctic, others Palse- 

 arctic or Nearctic. In all of them, we find the most primitive modern 

 survivors in the tropical regions, the most advanced types in the Holarctic. 



Canidd. — The Canida are the most cosmopolitan family of the order. 

 Tl is also the most progressive family in its adaptation to the open plains 

 and arid climate of the great modern continents. The gradual adapta- 

 tion of the race to these conditions from primitive arboreal forest -living 

 ancestors can be traced through successive stages in the Tertiary forma- 

 tions of Europe and North America, but most completely in the latter 

 country. The lengthening of the limbs and their adaptation for swift 

 running, the reduction of the long balancing tail to a short comparatively 

 unimportant organ, the perfection of the shearing and crushing teeth 

 and, especially, the steady increase of brain capacity are the chief lines 

 of progress. While most of the surviving Canida? conform pretty closely 

 to a single type, we find a tendency among their Tertiary ancestors to 

 branch off on the one hand into more predaceous, on the other into more 

 omnivorous types. Most of these have disappeared, but in the Oriental 

 Ethiopian and Neotropical regions we find in the genera Cyon, Icticyon 

 and Lycaon survivors of a more predaceous group which is known from 

 the Oligocene and Miocene of the Holarctic region. This group has- 

 disappeared from Holarctica by the end of the Tertiary; two or three 

 representatives are found in the Pleistocene of South America. Among 

 the more typical modern dogs, the wolves and foxes are the most pro- 

 gressive types, the jackals slightly less so, the African fennec retains 

 most nearly the primitive long tail, the South African Oiocyon, while 

 anomalous in possessing an extra molar tooth, is likewise normally primi- 

 tive in several characters and the Neotropical "dog-foxes'^ show a marked 

 resemblance in many details to the late Tertiary Canida^ of North Amer- 

 ica. The fact that the Canida? are preeminently adapted to open country 



