THE NEARCTIC REGION 161 



great importance ; only one genus ( Antrozous), containing 

 one species, being peculiar out of a total of nine. 



Summarizing, therefore, we find the Nearctic Region to 

 be characterized by the exclusive possession of only two 

 families of Mammals — namely, AntilocapridaB (the Prong- 

 bucks) and Haplodontida3 (the Haplodonts), and by the 

 presence of sixty-six genera, of which twenty-one are 

 restricted within its boundaries. On the other hand, in 

 addition to the two orders already mentioned, Monotremes 

 and Primates, the following important families are absent 

 in the Nearctic Region, although fairly well spread over 

 the Old World:— 



Suidoe (Swine). Hytenidre (Hyenas). 



Equidse (Horses). Erinaceidae (Hedgehogs). 



Myoxidse (Dormice). Pteropodidse (Fruit-eating Bats). 



Viverridse (Civets). Rhinolophidse (Leaf-nosed Bats). 



That some of these families did, however, at one time 

 exist on the North American continent has been shown by 

 recent palseontological discoveries. 



Section III. — Sub-division of the Nearctic Region 



The recent work of American naturalists, more espe- 

 cially that of Merriam (2) and of Allen (1), has greatly 

 increased our knowledge of the mammals of North 

 America and of their distribution. These naturalists have 

 further shown that the Sub-regions adopted by Wallace 

 in his well-known text-book on geographical distribution 

 are not altogether supported by the facts now known 

 to us. 



Mr. Allen, in his paper on the distribution of North 



L 



