h KEY TO THE GENERA OF NORTH 

 AMERICAN MAMMALS 



Animals are classified scientifically into groups of different 

 rank, known as orders families and genera, and the technical 

 name of any species consists of the name of the genus to 

 which it belongs, coupled with its own individual specific name. 

 If it shows definite variations in size, colour, etc., in different 

 parts of its range, these geographic races are indicated by a 

 third or sub-specific name. 



In the preceding pages the mammals have been arranged 

 by orders and families in their natural sequence, and the char- 

 acters of these larger groups explained. Inasmuch as a large 

 number of the genera of American mammals are represented in 

 our limits by but a single species, it was not deemed advisable 

 in a work of this kind to treat the several genera and the more 

 minute characters upon which they are based under separate 

 headings, especially as many of the generic characters are given 

 in the descriptions of the species. 



In order, however, to facilitate the identification of any 

 mammal which the reader may have in hand, the following key 

 has been prepared by which it may be traced to its genus, 

 while the page numbers following refer directly to the body of 

 the book where the descriptions of the several species may be 

 found. In this key the most obvious generic characters are 

 contrasted and the dentition of each genus is given. In stating 

 the dental formula it will be understood that the figures indicate 

 the number of teeth on one side of the jaws only, the number 

 above the line referring to the upper jaw, that below to the 

 lower; the letters indicate : i, incisors, c, canines, p, premolars, 

 m, molars. 



Only genera treated in the foregoing pages are included. 



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