FEATHERS OF BIRDS. 



575 



observations. It will be necessary in order to 

 obtain a clear idea of the several steps of the 

 process to be described, to advert to the structure 

 of a feather in its finished state. For this pur- 

 pose we need only examine a common feather, 

 such as that represented in Fig. 228, where s is 



228 



229 



230 



231 



the posterior surface of the solid stem, which, it 

 will be perceived, is divided into two parts by a 

 longitudinal groove, and from either side of which 

 proceed a series of laminae, composing, with their 

 fibrils, what is termed the vane of the feather 

 (v). The lines from which these lamina? arise, 



