6 EXPLANATION OF THE WORK. 



change the fact is indicated by the presence of a f preceding the number 

 of specimens. 



Classification: In the present state of our knowledge of birds of 

 the world no system of classification yet evolved can be considered as 

 more than tentative. That proposed by Gadow (1892) has much to 

 recommend it, but in a work of this character, convenience of reference 

 is an important factor to be considered and I have, therefore, adopted 

 the sequential arrangement proposed by Sharpe in 1891 (and used in his 

 Hand List of Birds and later practically by Brabourne and Chubb in 

 their List of Birds of South America) for the Orders and Families, but 

 numerous changes in the nomenclature and arrangement of Genera and 

 species were unavoidable, being obviously desirable to conform with 

 their more modern usage. 



I am greatly indebted to the authorities of our leading Museums and 

 others for so generously granting requests for the loan of specimens 

 (including many types) and acknowledgments for such courtesies will 

 be made later, but I wish here to especially express my thanks to Dr. 

 Frank M. Chapman, Professor Robert Ridgway, Dr. C. W. Richmond, 

 Dr. Witmer Stone, and Mr. Outram Bangs for much valuable informa- 

 tion which has greatly aided me in my work. 



CHARLES B. CORY. 



