284 TURDID.E. 



The young in their first plumage are blackish-brown above, 

 each feather having a median spot or streak of pale rufous : 

 lower parts light rufous-brown, with terminal dark spots. 

 The males as soon as fledged can be distinguished by 

 their darker colour above and their more distinct spotting 

 beneath ; after their first moult, they are intermediate in 

 the appearance between the adults of either sex. 



Some of the supposed laws which have been thought to 

 govern the assumption of peculiar styles of plumage in birds 

 having been previously stated (p. 213), a few remarks on the 

 disposition and situation of the feathers themselves may 

 here be added. It is not, however, intended to attempt to 

 describe the structure and growth of a feather, the most 

 complicated of all the varied products of the skin in ani- 

 mals, such minute anatomical and physiological details 

 being out of place in this work ; but the reader who is 

 inclined to pursue the subject may consult with advantage 

 Frederic Cuvier's observations on Feathers in the 'Memoires 

 du Museum d'Histoire Naturelle ' (xiii. p. 327), Prof. 

 Owen's article " Aves," in the ' Cycloptedia of Anatomy 

 and Physiology ' (i. pp. 349-353), or, still better, Prof. 

 Burmeister's note appended to the first section of Nitzsch's 

 ' System der Pterylographie ' of which a translation was 

 published by the Ray Society in 1867. 



In young birds the first feathers are preceded in their 

 passage through the skin by a bundle of downy filaments 

 enclosed in a sheath which soon crumbles away ; but after- 

 wards, at the regular period of moulting, each old feather is 

 the pioneer of that which is to follow. The natural moult 

 proceeds by degrees, and the quill-feathers of the wings and 

 tail are generally shed and renewed by pairs. 



" Although the feathers of Birds appear to be an entire 

 and uniform covering, they do not arise equally from every 

 part of the body, but only from such parts of the skin as 

 arc least liable to be afi"ected by the motion of the conti- 

 guous parts, such as the motion of the limbs. 



" The feathers arise pretty equably on the head where 

 there is no motion ; and silong the back ; on the wings 



