ORIGIN ( 



205 



le teeth or added horns and appendages of the skull ; it 

 ; still more frequent in added exoskeletal characters, such 

 s dermal ossicles and armatures. 



The contrast between the wolf (Canis lupus), the arctic 



^ — GEOGRAPHIC DISTRIBUTION - 



fox (Alopex lagopus), and the red fox (Vulpes vulpes) 

 may, moreover, be adduced for four purposes: first, to 

 direct attention to the nature of the numerical characters 

 which separate these three genera; second, to direct at- 

 tention to the fact that these numerical characters are 

 very inconspicuous and unimportant in contrast with 

 characters of proportion ; third, to illustrate the extremely 

 slow development in time of new numerical characters; 

 fourth, to illustrate the difference between paleontological 

 and zoological observation, a difference which is graphic- 

 ally represented in the diagram (Fig. 2). 

 As to time Vulpes has been separated from Canis for an 



