OF THE KINDS OF FEATHERS. 15 



short tube, scarcely distinguishable from the pithless shaft. This stem either emits no barbs, 

 just like hair, or gives origin to a few barbs (frequently only one or two), and these always at 

 the extremity of the naked shaft. These filoplumes are probably common to all birds, at least I 

 have never sought them in vain where I have taken the necessary trouble. Those standing very 

 close to the contour-feathers are shorter, and entirely covered by them, but in most passerine 

 birds, especially in Fri-ngilla, Sylvia, and Turdus, some longer filoplumes occur at the nape, and 

 these project and pass beyond the apices of the neighbouring contour- feathers. In the genus 

 Trichophorus TEMM. ; they even project a long way and curve downwards, in the form of simple, 

 barbless hairs. Filoplumes of a different and far more highly developed kind occur in the genus 

 Halieus, ILL. (Carlo, MEYER), in which they almost acquire the character of contour-feathers, for 

 I believe that the delicate, narrow, white, downy feathers which project on the neck from the 

 otherwise metallic black plumage of this genus of birds must be regarded as filoplumes, as 

 although they are furnished with perfect vanes, they agree both in position and in the slenderness 

 of the stem and other parts with the feathers of this kind. 



I think I have described the structure and kinds of feathers sufficiently for the necessi- 

 ties of this work, and now pass to their position as the true subject of my present communication, 

 although I well know that the preceding furnishes but a very scanty indication of the infinite 

 differences which may be detected by a careful study of the plumage of birds. 



