138 ELEMENTS OF ORNITHOLOGY. 
radiating directly from the summit of the quill. Filo-plumes, 
or thread-feathers, much resemble hairs, as they are long and 
very narrow, with a rudimentary vane. Some of these are 
bristly and called setaccous; and many Birds have a row of 
bristles or vibrisse bordering the opening of the mouth or gape, 
and these are particularly long in the Goatsuckers *. 
Fig, 141. Fig. 142. 

Fig. 141. DraGram or A Fearuer (with only three of its barbs indicated). 
A. Axis. Q. Quill. R. Rachis, or shaft, or seapus. W. Vane, vexillum, or 
pogonium. F. Front half of vane or outer web. H.V. Hinder half of 
vane or inner web. B. Three barbs or rami. 0. Barbules or radii. 
H.R. Hyporachis or aftershaft. 
Fig. 142. Dracram (after Nitzsch) or PARTS OF WEB. 
BB. Two barbs in vertical section. 6'b', Anterior barbules. 0242. Poste- 
rior barbules. c¢. Barbicels, or barbulets, or hamuli, or hooklets. 
Certain down-feathers are called pulviplumes because the 
ends of their barbs habitually break up into a fine powder called 
powder-down, such as may be remarked on Parrots. 
The ordinary feathers which clothe the body and hide the 
down are called contour feathers, Their basal barbs are com- 
monly soft. 
* See ante, pp. 86, 87. 
