VERTEBRATA. 97 



D. The Feathers of the Pigeon. 



1. What parts of the body are not clothed with feathers ? 



2. Are these parts protected in any other way ? 



3. Have the feathers a regular arrangement like fish 



scales ? 



4. Why are feathers always directed backward ? 



5. Is the contour (outline) of the body made more 



regular by being clothed with feathers ? 



6. Identify the following varieties of feathers: — 



a. Tail-feathers. 



b. Wing-feathers. 



(1) Primaries, the feathers attached to the 



hand and wrist. 



(2) Secondaries, the feathers attached to the 



forearm. 



(3) Coverts, the feathers covering the rest of 



the wing. 



c. Contour-feathers, the feathers which give shape to 



the body. 



d. Down-feathers, small feathers without definite 



outline lying next to the body. 



7. Which are the strongest feathers ? Why ? 



8. Identify the following parts of a tail- or wing- 



feather, — 

 (a) the shaft, the central axis of the feather ; 

 (6) the quill, the proximal hollow part of the shaft ; 

 (c) the vane, the flat lateral parts of the feather ; 

 (c?) the barbs, the parts which make up the vane ; 

 (e) the barbules, the small bi-anches of each barb. 



(The barbules on one side of the barb may be 

 called distal, those on the other side proximal.) 



9. Observe (1) the arrangement of the barbs and bar- 



bules with regard to each other. Show this ar- 



