ORNITHOLOGICAL CLASSIFICATION 135 



consulting books ; but the elaboration of a detailed 

 account of the species, such as is to be found in the 

 following pages, could obviously be accomplished only 

 by much labour of a different kind. British Birds, 

 vol. i., Preface. 



2. 



In again presenting to the public some of the results 

 of my long-continued examination of the habits and 

 structure of the birds of Great Britain, I may be per- 

 mitted to offer a few retrospective remarks. The 

 introduction to the first volume contains, among other 

 matter, a description of the skeleton, the organs of 

 flight, and the digestive apparatus of birds, rendered 

 necessary by the neglect of anatomy evinced by our 

 most esteemed ornithological writers, who in their 

 treatises have either expressly maintained, or practically 

 shown it to be their opinion that the inspection of the 

 external parts is a sufficient guide to zoological know- 

 ledge. In avoiding this error, as I cannot but esteem 

 it, I have not fallen into the opposite one of considering 

 an acquaintance with the internal structure of animals 

 alone necessary to their historian, but have entered 

 into details as to external form, and the texture and 

 colours of the cutaneous system, much more extended, 

 and, if my efforts have been successful, not less accurate, 

 than those which I have met with in any of the works 

 alluded to, and have presented numerous facts relative 

 to the habits and economy of the different species. 



