PREFACE. XXI 



the almost unlimited use of his Manuscripts and rich col- 

 lections, the author has no hesitation in saying that he 

 could never have extended the Manual to that depart- 

 ment, or presumed to enter upon a field, to which he was 

 previously almost an entire stranger. Assistance, however, 

 has been not the less afforded him in the other Classes. 

 Mr. Yarrell's well-known practical acquaintance with our 

 British Birds has enabled the author to detail more at 

 length the changes of plumage to which some species are 

 liable, and to correct a few errors into which previous 

 writers had fallen on this subject. The same gentleman 

 kindly volunteered an accurate description, accompanied 

 by measurements, of the egg of every species, of which 

 his extensive collection afforded specimens; thus enhancing 

 the utility of the work by an addition, which, but for 

 this circumstance, the author would have been unable to 

 supply. He begs it may be distinctly understood that 

 this portion of it is from the pen of Mr. Yarrell. 



To Mr. Gray, he desires to make an acknowledgment 

 of the readiness with which he has at all times allowed 

 him to consult the specimens in the British Museum. The 

 same return must be made to the officers of the Zoolo- 

 gical Society for similar liberty to examine a few specimens 

 contained in their collection. 



In conclusion, the author may state that he has no 

 intention of extending his work to the Invertebrate Divi- 

 sion of the British Fauna. In the present advanced state 

 of the Science, a complete Manual of all the Animals oc- 

 curring in these Islands can only be accomplished by the 

 united labours of many individuals. With the view, how- 

 ever, of continuing his researches into that portion of it 

 which is here treated of, he begs to solicit such observa- 

 tions, notices of new or rare species, and, where it may 



