4 VETERINARY STUDIES 



pairs of incisors at about birth ; the next pair at about 14 days, 

 and the corner pair by about 3 weeks. Thus the calf has a 

 full mouth of temporary incisors at about one month. 



Fig. 3. — Six Years, Lower Jaw. 



The incisors are replaced in pairs beginning with the center 

 at 1^2, 2%, 3~y 2 and the corner pair at 4^ years. 



In young horses, the grinding surfaces of the incisors are wide 

 from side to side. At about 13 to 15 years these surfaces are as 



Fig. 4. — Eight Years, Upper Jaw. 

 Note. — Figures 4 and 5 are drawn on different scales. 



wide from before back as from side to side. In very old horses, 

 this surface is narrow from side to side. 



The incisors of young horses extend at nearly right angles from 



