PREFACE. xi 



A few words may be added on some additional features which I have thought it desirable to 

 introduce into the Work. It was impossible, in the first instance, to number the pages, on account 

 of the irregular order in which, from various causes, it was necessary that the subfamilies should be 

 issued ; but in the Table of Contents I have shown how the numbers of the pages should run with the 

 several articles, and this paging will be found greatly to facilitate the consultation of the "Work. 

 During the five years of its progress much additional matter has been carefully collected, which is 

 added in the Appendices, where many new species, and other information published or met with 

 subsequently to the publication of the several articles to which they refer, will be found recorded, for 

 the purpose of completing, as nearly as possible up to the present time, the summary of our knowledge 

 of the species belonging to each genus. Lastly, to facilitate the finding of the names of those birds 

 which have been figured in various standard ornithological works of large extent, I have given a 

 series of Lists of the Names employed in this Work, with references to each plate of those works in 

 consecutive order, which I trust may prove useful in naming collections from those great stores of 

 published figures, by enabling the student at a glance to obtain the information he desires with regard 

 to any particular figure. 



G. R. GRAY. 



Hampsteacl, August 20. 1849. 



POSTSCRIPT BY THE ILLUSTRATOR. 



It is perhaps scarcely necessary to state that the Illustrations of this Book have no claim to be con- 

 sidered as works of art. My constant object has been to represent, as closely as possible, those 

 characteristic variations of form which are relied on by ornithologists as the distinctive marks of generic 

 separation. 



When I accepted the office of Secretary to the Zoological Society, and found myself no longer able 

 to devote to the completion of this series of plates the time which the work demanded, I was fortunate 

 enough to obtain the assistance of Mr. Wolf of Coblentz ; and I have the pleasure of believing, that, as 

 I thus secured the best available talent in Europe as a substitute for my own pencil, my friends will 

 have no cause to regret that the latter part of the Work has been intrusted to another hand. 



D. W. MITCHELL. 



Montague Street, Aug. 29. 1849. 



