428 
Dentition as indicative of the Age 
The cutting of the corner incisors, or fourth pair of broad 
teeth, takes place on an average about nine months after the 
lateral incisors are in the mouth, and may be taken as an indi- 
cation that the sheep is over the age of three years. In some 
cases the corner teeth do not appear till the animal is nearly 
four years old, so that there is a possibility of a mistake being 
made as to the age, to the extent of a year, by an examiner who 
contents himself with an inspection of the corner incisors. No 
difficulty, however, would be experienced in deciding whether 
the corner incisors represent three years or four years, if the 
state of the other incisors is taken into account. At four years 
of age the six broad teeth will show marks of wear, the central 
incisors especially will be worn hollow on their upper sur- 
faces, the middles and laterals also showing well-marked tables 
in the place of sharp cutting edges ; while the recently cut 
corner incisors, supposing their eruption to have been delayed 
till the sheep was nearly four years old, will present a marked 
contrast to the rest of the teeth which have suffered from attri- 
tion. These appearances are shown in the drawing (Fig. 41) 
of the mouth of a sheep of the age of four years. 
After the age of four years, and indeed from the time of the 
completion of permanent dentition, whether early or late, the 
changes which are effected in the form of the incisors by wear 
vary according to the nature of the food, and the examiner must 
be content to limit his inquiries to the period within which is 
comprised the eruption of the permanent teeth. 
