O r\. 



PREFACE. 



The object of this book is explained by its title ; and 

 the Introduction so fully refers to the circumstances under 

 which it was undertaken, that I feel there is no need 

 for prefatory remarks, except as a means of expressing 

 my thanks to the brother ornithologists who have so kindly 

 aided me in the production of my work. 



G. E. S. 



/i-4^^3 



