CHAPTER IX 



HISTORY OF THE ARTIODACTYLA 



The artiodactyls are and for a very long time have been 

 a very much larger and more variegated group than the peris- 

 sodaetyls, and the Old World has been and still is their head- 

 quarters and area of special development, where they are 

 represented in far greater number and variety than in the 

 New ; the perissodactyls, on the other hand, flourished espe- 

 cially in North America, as was shown in the preceding chapter. 

 At the present time the artiodactyls are the dominant ungulate 

 order, far outnumbering all the others combined, and include 

 an assemblage of varied types, which, when superficially 

 examined, appear to be an arbitrary and unnatural group. 

 What could seem more unlike than a dainty little mouse-deer, 

 no larger than a hare, a stag, a camel, a giraffe, a bison and 

 a hippopotamus ? Yet, in spite of this wonderful diversity 

 of size, proportions, appearance and habits, there is a genuine 

 unity of structure throughout the order, which makes their 

 association in a single group altogether natural and proper, 

 especially as these structural characters are not found united 

 in any other group. 



It would be superfluous to enumerate all of the diagnostic 

 characters which, on the one hand, unite all the living and 

 extinct artiodactyls and, on the other, distinguish them from 

 all other hoofed animals, and it will suffice to mention a few 

 of the more significant of these features. 



As the name implies, the artiodactyls typically have an 

 even number of toes in each foot, four or two ; though this 

 rule may be departed from and we find members of the order 



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