PEEFAOE. 



This book has been written to give collectors and students 

 who are not specialists, a ready means of identifying the families, 

 genera and species of our Vertebrate Animals. In deference to 

 the uniform experience of botanists, and in view of the remarkable 

 success achieved by Dr. COUES, in the application of the method to 

 Ornithology, the author has adopted the system of artificial keys. 



To keep the book of a size convenient for field use, class and 

 ordinal characters have been abbreviated, since they do not lie 

 directly within the purpose of the work ; generic characters have 

 been confined to the " key," under the head of each family, 

 while for specific characters, only such points have been gen- 

 erally retained, as are distinctive as well as descriptive. The 

 same necessity has led to the suppression of many of the doubt- 

 ful or nominal "species," which still encumber our systematic 

 works, and to the omission of synonymy and references to auth- 

 orities, excepting in cases of recent or original changes of 

 nomenclature. 



Use has been freely made of every available source of infor- 

 mation, and it is believed that the present state of our knowl- 

 edge is fairly represented. 



The account of the Mammals has been chiefly compiled from 

 PROF. BAIRD'S " Mammals of North America," in the light of 

 the recent revisions by Mr. J. A. ALLEN, Dr. COUES, and Prof. 

 GILL. I am indebted to Mr. B. H. VAN VLECK, of Cambridge, 

 Mass, for the revision of the proof-sheets of the Mammals and 

 the Turtles. 



I wish further to express my deep obligation to Dr. ELLIOTT 

 COUES, having by his advice and consent, made free use of all 

 his published writings. These have been drawn upon especi- 

 ally in the preparation of the keys to the Warblers, the Hawks, 

 and other difficult groups, in the descriptions of the Water 



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