PREFACE. 



I HAVE little to say in this Preface, beyond the ex- 

 pression of my sincere regret for the delay which has 

 occurred in the publication of the work. That delay has 

 arisen from causes which it would not interest the public 

 to be informed of, and which I have no wish to put 

 forward for the sake of deprecating the displeasure or 

 disappointment which it may have excited. 



A much more agreeable task is that of acknowledging, 

 which I do with feelings of sincere gratification and deep 

 thankfulness, the extensive and valuable assistance which 

 I have received from so many of my fellow-labourers in 

 the field of Natural History. Their names are mentioned 

 in connection with their contributions, in various parts of 

 the work ; and it would be invidious to particularise them 

 here, lest, through inadvertence, any should be omitted. 

 To one and all I beg to offer the tribute of my grateful 

 thanks. 



Selbornk, Hants. 

 July, 1853. 



