332 
On the Teeth of the Ox, Sheep, and Pig, 
Fig. 33* 
the edges of either the first, second, or third pair, these teeth will 
have acquired their full development, the second pair becoming 
nearly level with the first, or the third with the second, as the 
case may be. The corner incisors, howevei", although they more 
quickly acquire their full size after being cut, rarely gain the pro- 
portionate level of the others. 
When dentition is completed, any opinion which is given of 
age, must be drawn from the general appearance of the animal, 
rather than from the condition exclusively of the teeth. Never- 
theless the changes they gradually undergo will assist in the 
inquiry. At four years old the edges will be worn off both the 
second and third pairs of incisors, which will now present a 
similar appearance to that described as denoting the attrition of 
the central pair at three years. From four to five years the hol- 
lows on the wearing surface of all the incisois will increase, and 
by five years they will have lost the broad chisel form they had 
when young, and there will be no longer any overlapping of their 
edges. Fig. 34 gives a very good representation of the teeth at 
five years old, and is inserted to fix these things more firmly upon 
the memory. 
Increasing age after five years is indicated by a diminished 
height, a flat or broad wearing surface, a less conical shape of the 
crowns of the incisors, discoloration of the enamel, and spaces 
between each tooth. 
♦ Fig. 33. Front of the lower jaw at three years and a quarter, showing that 
the incisors are all permanent. Natural size. 
