PREFACE TO THE FIFTH EDITION. lll 
In the nomenclature and classification of the Birds, I 
have followed exactly the “Check List of North Ameri- 
can Birds,” published by the American Ornithologists’ 
Union. In the preparation of analytical keys to the 
genera of Birds, I have made large use of Ridgway’s 
“ Manual of North American Birds,” and of Coues’ “Key 
to North American Birds.” In the arrangement of the 
Mammals, I have been guided primarily by Professor 
Baird’s “ History of North American Mammals.” In the 
Rodentia, I have made use of the elaborate monographs of 
Dr. Elhott Coues and Dr. J. A. Allen; and in the other 
groups reviewed by Dr. Coues, I have adopted most of 
his conclusions. In the Cetaceans, I have used chiefly 
the papers of Mr. Frederick W. True and Prof. E. D. 
Cope, and both these naturalists have kindly furnished me 
with unpublished catalogues of the species recognized by 
them. 
In the preparation of the present edition I am also 
personally indebted for aid in various ways to Prof. Ed- 
ward D. Cope, Mr. Leonhard Stejneger, Prof. Charles H. 
Gilbert, Prof. Oliver P. Hay, Mr. Frederick W. True, Mr. 
Robert Ridgway, Mr. Amos W. Butler, Dr. J. Sterling 
Kingsley, Mr. Charles H. Bollman, Dr. Stephen A. Forbes, 
Mr. Barton W. Evermann, and others. I may again refer 
to the obligations acknowledged in the earlier edition, — 
especially to my indebtedness to Dr. Elliott Coues, Dr. 
Theodore Gill, Prof. Edward D. Cope, Prof. Herbert E. 
Copeland, and Mr. Edward W. Nelson. 
DAVID S. JORDAN. 
BLOOMINGTON, INDIANA, 
June, 1888. 
