Covering of Animals. 



The coverings of animals are adaptations to the conditions of 

 their life, and are all interesting objects of study. Hair, scales, 

 thick epidermis, bony plates, spines, and feathers of various forms 

 are in endless varieties. 



Feathers. 



Feathers are characteristic of birds and are very interesting 

 when their true meaning is seen. For a lesson on feathers, pro- 

 vide a bird freshly killed, a duck or a fowl from the market, and a 

 quantity of feathers sufficient to allow each pupil to have exam- 

 ples of each kind in hand during the lessons. If the question 

 is -asked : "What is the use of feathers ? " the answer that 

 will usually come is: "To keep the animal warm.' J This is one 



Fig. 80. A feather, also separate parts magnified; a, quill feather of a pigeon; b, 

 four barbs (magnified) from the vane, showing the barbules, some separated, some still 

 clinging together; c, a cross section of three barbs showing how they cling together; 

 d, a barb and barbules of the down; at one side a barbule more highly magnified. These 

 always remain loose. 



use of feathers, but the lesson is to show that this is by no means 

 the only one, perhaps not the most important one. (The uses are 



