ZOOLOGY. 



when running. Make outline drawings of the shank and toes of all the 

 types of birds which can be found, and discuss the differences in the light 

 of the habits of the birds. Make figures of the varieties of webs found 

 in the aquatic birds. 



423. Covering. The form of birds as outlined above is 

 much modified by the presence of feathers. They increase the 

 stretch of the wings and the surface exposed to the air, and 

 thus are important as aids to flight. In addition they are pro- 

 tective in several respects. The pigment possessed by the 

 feathers serves to enhance greatly the beauty and variety of 

 the members of the group. That the color patterns are of 



FIG. 201. 



FIG. 20 1. Diagram showing the tracts where the principal growth of feathefs occurs 

 (Upupa epops). From Bronn. The dotted areas are the pteryla. 



Questions on the figure. Is this a dorsal or a ventral view? Find a 

 figure giving the opposite view of some bird and compare with this. Is 

 there variety in the different species of birds as to the distribution of the 

 growth of feathers? 



