CHAPTER III. 



EXTERNAL PARTS OF BIRDS. 



THE subjects to be noticed in this chapter are much 

 less interesting and instructive than those slightly 

 glanced at in the former one ; but as the descriptions 

 of all birds are founded chiefly upon the colours of 

 the external parts, and as these are all that we know 

 about those species which belong to science only as 

 museum specimens, this part of the subject becomes 

 necessary in a general sketch descriptive of the class. 

 Its minor importance will, however, enable us to treat 

 it more briefly. 



The external parts of birds, as they immediately 

 present themselves to the eye, consist of three kinds 

 of surfaces horn, naked skin, and feathers. The 

 first of these requires little description, being only the 

 bill, the claws, and partially the scaly covering of the 

 naked parts of the feet and toes, which is most con- 

 spicuous on the upper sides of the toes, and the ante- 

 rior sides of the tarsi. The naked surfaces are also 

 limited in extent, being confined to the head, portions 

 of the neck in some genera, and those unfeathered 

 parts of the feet and toes which are not covered by 

 horny scales. The feathered parts are much more 

 important in the popular description of birds, as it is 

 to their forms and colours that the attention is first 

 attracted. 



