IV INTRODUCTION. 



In the adoption of generic and specific names, it has been 

 thought right to use, wherever it was possible, that which 

 was first applied to the species. As far as regards the spe- 

 cific names, there is comparatively little difficulty in the 

 application of this simple rule ; but generic names have been 

 used by different authors in senses so widely different, and 

 the groups which they were meant to designate have been so 

 variously extended and restricted, that it was no easy matter 

 to determine, where several names had been used, which of 

 them ought to be preferred. . 



Great attention has been paid in giving a reference to 

 the work in which, and the date when, each genus and its 

 synonyma were respectively published. 



Under each species there have been appended all the names 

 under which the bird has been mentioned since the establish- 

 ment of the Linnean system of Nomenclature, and references 

 are given to the works in which these names were first used. 



These are followed by a reference to a few of the best 

 original figures of the species. 



To assist in the determination of the arrangement and the 

 distinction of the specimens, the skeletons and breast-bones 

 contained in the collection are marked under each species. 



Great care has been taken by Mr. GEORGE ROBERT GRAY, 

 the Senior Assistant in the department, in the determination 

 of the species, the verification of their synonyma, and in 

 examining the priority of the generic and specific names. 



The British Museum is fortunate in having received a 

 large portion of its species (either in presents, or by way of 

 exchange or purchase) from the several authors both in this 

 country and abroad by whom the species to which they 

 belong were originally described, or from the collections in 

 which they first received their names. In such cases there 

 can be no doubt of the specimens being ascertained repre- 

 sentatives of the names they bear. 



