Mr W. Macgillivray on the Covering of Birds. 12T 



exist, however, in the other parts of the body, but are not 

 readily distinguishable from the down-feathers properly so called. 

 If it be necessary to give these feathers a name, they may be 

 called Flake-feathers. 



In most birds, after the feathers have been removed, we find 

 a sort of envelope, consisting of hairs as it were, set so widely 

 and so small in themselves, that they might readily be overlook- 

 ed. These are the hairs that are singed off in a common fowl 

 after it has been plucked. In Phasianus colchicus their struc- 

 ture is as follows : from a very short bulbiform tube rises a very 

 slender roundish piliform shaft, resembling a hair of the human 

 head, but much smaller and straight, which, at the extremity, 

 gives off two or three short simple barbs on either side. This^ 

 is the most simple modification of the feather, if we except the 

 quills of the Cassowary. 



In all nestling birds, before they have received their full plu- 

 mage, the skin is covered with a greater or less quantity of 

 down, resembling that described above as occurring in adult 

 birds. This down is generally more or less developed, even be- 

 fore exclusion from the Qgg. It consists of two orders of plu- 

 mules. One set, which is connected solely with the skin, is si- 

 milar in structure and relations to the down of the adult bird, 

 each plumule consisting of a tube, out of which issues a 

 pencil of filaments, furnished with filamentules. The other set, 

 which, at first sight, is not distinguished from the former, being 

 blended with it, is of the following nature. The plumules at 

 first arise from the skin in the ordinary manner and form, but 

 liaving fewer filaments than the others. Shortly after, when the 

 feathers begin to sprout, they are observed to be elevated from 

 the skin, being borne upon the tips of the feathers. The tips 

 of the extreme barbs of the feathers are drawn together, and 

 united into a point by a scaly envelope, similar to that which 

 incloses the feather itself during the first stages of its growth. 

 From this point there proceeds a pencil of filaments, consisting 

 of a variable, but generally small number. These filaments 

 have two lateral series of filamentules, and are loose and float- 

 ing, and more or less spirally twisted. The filaments are con- 

 tinuous with the tips of the barbs, as is proved by discussing 

 the point of adhesion with a needle, when the scales fall off, 

 and the filaments remain attadied to the tips of the barbs, and 



