6o 



F/RSr LBSSONS IN ZOOLOGY 



fied portions of the skin. Of what uses are the feathers 

 to the bird? 



The feathers are of several kinds or types, each of 

 which has a name. In tlie wings and tail are long, stiff 

 feathers called cjuiU feathers; those which overlie the 

 whole body and bear the color pattern are called contour 

 feathers ; the small soft ones which cover the body more 

 or less completely (being, however, mostly hidden by the 

 contour feathers) are called down feathers or plumules, 

 while, finally, the scattered, slender, soft, or stiff hair-like 

 ones, with the thin bare stem and small terminal tuft of 

 branches, are called thread feathers or filoplumes. 



Pull a quill feather from the wing and examine it in 

 detail. Note the central stem or shaft, composed of two 

 parts, a basal hollow transparent quill, which bears no 

 \\eb and by which the feather is inserted in the skin, and 

 a longer terminal four-sided part, the rachis, which bears 

 on either side a web or vane. Examine the vane with a 

 lens and see that it is composed of many narrow linear 



plates called barbs, and that 

 each barb is fringed in turn 

 with smaller branches called 

 barbules. Finally, each 

 barbule bears many fine 

 barbicels or hamules, which 

 can be seen with a micro- 

 scope. The barbs compris- 

 ing the vanes are inter- 

 locked with each other (fig. 

 33), thus forming a true web 

 „.,,.,,,, , and giving the vanes, com- 



JlG. 33. — Bit of bird s feather, greatly 



magnified; s, shaft; /<, barb; /./, pOSed of small, weak parts, 



i^^^.i^ ' * ' much strength and power 



of resistance. Rub the 

 feathers from tip to base, and, examining the vanes with 



