PREFACE IX 



*' Quadrupeds of North America" have been used. The senior author 

 of the lirst named work. Dr. Witmer Stone, of the Academy of Natural 

 Sciences, Philadelphia, has been so good as to read critically the whole 

 manuscript of Mammals. 



The figures which have been introduced are intended to illustrate 

 and explain the most important diagnostic features of the various 

 groups of animals and to illuminate the keys and make them more easy 

 to comprehend, and have been copied mostly from monographs, special 

 treatises and textbooks; the author here extends his thanks to the 

 authors of these figures and the pubUshers of the books in which they 

 are found for the privilege of using them. 



In the use of scientific names of animals the laws of priority estab- 

 lished by the International Commission of Nomenclature have been 

 followed. The name of the author of each species, subspecies and genus 

 follows the first mention of it in the descriptions, as is customary, 

 and in those cases in which an author originally placed his species 

 in some other genus than the one here given, his name is in parentheses. 

 Wherever an author's name appears more than once in the same genus 

 it is usually abbreviated after the first occurrence. No other abbrevia- 

 tions of the names of authors' appear except in the case of Linnaeus, 

 whose name is always shortened to "L," wherever he appears as the 

 author of a scientific name. 



Much of the labor of compiling this work has been done at Cold 

 Spring Harbor, Long Island, and the author wishes to express his great 

 obligation to his friend and colleague, Dr. Charles B. Davenport, for 

 his constant support and encouragement during its progress. He also 

 wishes to thank his pubHshers, P. Blakiston's Son and Company, 

 for their many courtesies and their readiness in meeting his wishes. 

 H.WERFOED College 



Haverford, Pa. 



