PLUMAGE OF BIRDS. 



233 



111 



semi-annular scales, ending on each side in a longitudinal furrow, 

 and these birds he termed the Scutipedes. In one section of the 

 Tyramii, Cuv., the scuta surround the tarsi as complete rings. 

 Where the carneous parts of the muscles are continued low do^vn 

 upon the legs, as in the Owls, a covering of feathers is co-extended 

 to preserve their temperature. 



§ 165. Ajjpendages of the Tegument, — The Vertebrate classes 

 have each their characteristic external covering : the cold-blooded 

 Ovipara are naked, or their external surface is defended only by 

 hard scales or plates {squamcB and scuta) ; but the warm-blooded 

 classes require to be invested by an integument better adapted to 

 maintain the high degree of temperature 

 peculiar to them : hence quadrupeds are 

 clothed with fur and hair, and birds with 

 down and feathers. 



Feathers are the most complicated of 

 all the modifications of the epidermic 

 system, and are quite peculiar to the class 

 of Birds. They are proverbially light; 

 and, as the eloquent Paley well observes, 

 ^ every feather is a mechanical wonder ; ' 

 ^ their disposition, all inclined backward, 

 the down about the stem, the overlapping 

 of their tips, their different configuration 

 in different parts, not to mention the 

 variety of their colours, constitute a vest- 

 ment for the body so beautiful, and so 

 appropriate to the life which the animal is 

 to lead, as that, I think, we should have 

 had no conception of anything equally 

 perfect, if we had never seen it, or can 

 now imagine anything more so.' ^ 



NotAvithstanding the varieties of size, 

 consistence, and colour, all feathers are 

 composed of a quill or barrel, fig. Ill, «, 

 a shaft, b, b, and a vane or beard, c, c; 

 the vane consists of barbs, fig. 112, e, and 

 barbules, ff 



The quill (^calamus), by which the fea- 

 ther is attached to the skin, is larger and shorter than the shaft, 

 is nearly cylindrical in form and semi-transparent ; it possesses 



Lxvi*. p. 234. 



