PREFACE V 



he could find and carefully filed them for future use. Ridgway's 

 notes covered the diagnoses of genera and higher groups and partial 

 synonymies for many of the species and subspecies. Whenever pos- 

 sible, his manuscript has been included with the minimum of change 

 (other than addition to synonymies) permitted by more recent data. 

 In fact, it has been the present author's feeling that this -work should 

 be as largely Ridgway's as possible; thus, for instance he has kept 

 and included Ridgway's diagnoses of certain genera now relegated to 

 the position of subgenera, and where Ridgway's manuscript gave 

 extensive synonymies for extralimital forms, he has retained them 

 without attempting to supply equally detailed accounts for other 

 extralimital forms. However, all such manuscript material has been 

 thoroughly studied with the specimens and the literature; nothing 

 has been accepted merely because it was written. From the start, 

 the author has felt himself responsible for the entire contents of this 

 volume and has not considered himself as an editor of an unpublished 

 work. 



It has been a great regret to the author that he was not able to 

 begin this work while Dr. Richmond was still alive, as he was so 

 intimately connected with the first eight volumes and had a back- 

 ground of highly valuable experience with the work. It is hardly 

 necessary to state that much of the bibliographic and nomenclatorial 

 excellence of the first eight volumes was due to Richmond's profound 

 laiowledge of the literature and to his alert eye in reading proof. 



Measurements of specimens for use in preparing this volume were 

 made by the author and Dr. E. M. Hasbrouck under the author's su- 

 pervision. Maj. Allan Brooks contributed (before the present author 

 began this work) a series of notes on the colors of the unfeathered 

 parts of many of the species discussed herein. The outline drawings 

 of generic details, except those previously published, were made under 

 the author's supervision, by Mrs. Aime Awl, of the United States 

 National Museum staff. The drawings for the genus Cyanolimnas 

 are reproduced by kind permission of Dr. Thomas Barbour, from his 

 paper in the Auk for 1928. 



Since the publication of Part VIII of this work, Peters' "Check List 

 of Birds of the World" was begun, and four volumes have been pub- 

 lished so far. Inasmuch as these four cover all the groups treated in 

 the present part and those left to be treated in the remaining parts of 

 the present work, and especially inasmuch as Peters' work will be the 

 standard list for a long time to come, it has been deemed best to alter 

 somewhat the arrangement of the material herein presented. Ridg- 

 way's system begins with the highest and ends with the lowest groups, 

 while Peters is following the reverse order. Therefore, to make the 



