Feathers. 



53 



is strictly bipedal, as the fore-limbs never touch the 

 ground, being modified into wings. Like reptiles they 

 are oviparous and their eggs Fig . 22- 



are of large size ; in most cases 

 also the young are for a certain 

 period under the care of the 

 mother, by whose agency they 

 are provided with food. 



30. Feathers. Feathers 

 are epidermal processes se- 

 creted by long grooved papillae 

 and they are of several sorts. 

 The strong distinct feathers, 

 which have a central axis and 

 lateral expansions or vanes, are 

 called contour-feathers, while 

 the smaller soft feathers which 

 clothe the intimate surface of 

 the skin, which have soft or 

 woolly processes and no axis, 

 are called down-feathers. In 

 each contour-feather we notice, 

 firstly, the hole at the base (fig. 

 22, e) where it is thickened 

 around the base of the papilla ; 

 secondly, the slit-like hole, f, 

 marking the region above which 

 the sheath of the papilla has 

 split ; thirdly, the rachis, or the 

 square solid axis, b ; fourthly, 



the flat expanded* lamina, Or , barrel; b, rachis; c, vanes; 



vane, c, composed of separate 

 barbs, the margins of each of 



Contour-feather. 



