Feathers 21 
to be entirely naked; but a closer inspection shows 
scanty tufts of down scattered irregularly over the body. 
This, like the set of milk-teeth in mammals, is useful 
only for a time, and is later pushed out by the second 
or true plumage. Even more numerous than the down- 
Fig. 10.—Brown Pelican nestlings, showing feather papille on body and wings. 
About 1/4 natural size. 
tufts are little pimples or dots, many hundreds of which 
cover certain parts of the skin. Each of these will event- 
ually give rise to a perfect feather—quill, vane, barbs, 
and all. 
The under layer of skin, or dermis, is very thin in 
birds, much more so than in reptiles and other animals. 
