THE PIGEON 161 



surface of the body and give it its outline ; note their method of 

 overlapping and the smooth surface they present to the air. The 

 quills, which form the beating surface of the wings and the tail, 

 are elongated contour feathers. The down feathers are soft and 

 fluffy; they clothe the nestlings and are found also between the 

 contour feathers in the adult. The pinfeathers, or filoplumes, are 

 hairlike structures which lie among the other feathers and which 

 will be seen when these are removed. 



Note the arrangement of the feathers on the body. Observe 

 first those parts which are entirely bare, as the bill, eyelids, etc. 

 The greater part of the body is apparently covered by the contour 

 feathers, but a careful examination will show that there are dis- 

 tinct feather tracts and other parts which have no feathers. These 

 tracts can be distinguished better in a young pigeon or a sparrow 

 than in an adult pigeon, in which they tend to run together. It 

 will be seen that the down feathers and pinfeathers are present 

 on the tracts not covered by contour feathers. 



Besides the feathers, other epidermal structures are present 

 which help to form the outer covering of the body ; these are the 

 horny scales, plates, and claws on the legs and toes, and the horny 

 covering of the beak. 



Observe the color of the animal and determine if the color tracts 

 are bilaterally symmetrical. The color pattern of an animal in 

 a wild state has a strong tendency toward bilateral symmetry, but 

 domestication changes the action of natural selection, which has 

 given an animal its peculiar characters, and often results in the 

 confusion of the color patterns. The coloration of the European 

 rock pigeon, the wild ancestor of the domestic pigeon, is similar 

 to that of the common slate-colored domestic pigeon. 



Observe the general shape of the body. It is a compact, rigid 

 structure, a laterally compressed ellipsoid in shape, with a long 

 neck and large head, and large wings, feet, and tail. The shape 

 fits the animal for rapid locomotion through the air. The neck of 

 a bird is usually very flexible because the trunk is rigid,— a cor- 

 relation we found also in the case of the turtle. The large head 

 indicates intelligence, the large wings and tail a powerful flight, 

 and the strong feet ability to walk well. 



