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. A list of the principal papers which 

 have proved useful in the preparation of this work'may be found 

 on page 363. 



The writer is under deep personal obligations for assistance, 

 criticism and advice, to many persons, among whom I may 

 especially mention Dr. ELLIOT COUES, Prof. E. D. COPE, Dr. 

 THEODORE GILL, Prof. H. E. COPELAND, Mr. E. W. NELSON, Mr. 

 B. H. VAN VLECK, Mr. C. H. GILBERT and Dr. A. W. BRAYTON. 



The present edition is from the same stereotype plates as the 

 second. From the latter it differs in some changes of nomencla- 

 ture, in the correction of occasional errors, and in other minor 

 respects. A few additional species are included in the Addenda. 



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