i66 A GUIDE FOR THE STUDY OF ANIMALS 



mouth and teeth, finding the grinding teeth far back in 

 the mouth, the incisors in front, and the space where 

 the canines are missing. 



The male may have canines in the upper jaw. 



On the surfaces of the incisors are the depressions, 

 or "cups," by means of which age is determined. 



At six years the cups leave the lower center teeth ; at seven the 

 adjoining teeth ; and at eight, the outer lower teeth. At nine years 

 they leave the upper center incisors ; at ten, the adjoining teeth ; and 

 at eleven, the outer teeth above. At the age often years a spot appears 

 in the outer upper incisors, at fifteen years the groove has worn to the 

 center of the tooth, and at twenty-one years the groove is worn to the 

 bottom of the tooth. 



Questions. 



1. Describe the horse you studied as to its name or 

 number, its color, markings, weight, and size. Of what 

 type and breed is it a specimen } 



2. Upon how much of the foot does the horse walk } 

 How does this affect ease or speed of action } How does 

 an athlete imitate this in sprinting 1 



3. How many toes has each foot.? What advantage 

 or disadvantage can you see in this unusual structure .'' 



4. How is the hoof constructed to distribute the weight 

 over a surface broader than the leg .'' How general is this 

 among terrestrial animals .-' 



5. What is the difference in the position of the chest- 

 nuts of the fore and hind legs } 



6. Where in the foreleg is a springiness permitted by 

 curvature ? Where does the back leg accomplish the same 

 thing .' 



7. How do you account for the elongating of the 

 face ? 



