406 
Dentition as indicative of the Age 
Remarkably well-developed tusks were an exceptional feature 
in the mouth of the animal from which the above illustration 
was taken, in other respects the teeth present the appearances 
which are ordinarily observed at the age of four years. The 
only milk-teeth now remaining are the four corner incisors, 
which are much worn and quite different from the broad per- 
manent teeth, with which they are not likely to be confounded. 
In the lateral incisors the wear has affected the anterior 
edge of the tooth, and the cavity extends completely across 
the table, which is not therefore fully formed. In the cen- 
tral incisors there is a line of worn surface quite round the 
central cavity, and the table may be properly described as fully 
formed . 
Incidentally it may be remarked that between the com- 
mencement and completion of the fourth year the dental 
changes include the cutting of four permanent incisors, two 
in each four tusks, and eight molars — two on each side of both 
jaws, making sixteen teeth, which are all advancing at the same 
time. 
Between four years and five, the corner temporary incisors 
are removed, and the permanent teeth occupy their places. 
Indications of the change are seen at four years off in the 
upper corner incisors, and in a few months the temporary teeth 
are displaced, and the permanent organs are in the mouth, but 
their edges do not meet until the fifth year is completed, and 
even then the contact is limited to the anterior part, and a 
triangular space, similar to that which can be seen between the 
upper and lower corner teeth in the mouth of the yearling, may 
be recognised when the lips are separated at the side of the 
mouth. The shell-like character of the corner permanent teeth 
is the special indication of five years old. 
In the next figure (Fig. 14) the condition of the incisors in 
the five-year-old mouth is shown. 
In the illustration it is evident that the corner permanent 
incisors show but slight indications of wear on the completion 
of the fifth year, only the anterior edge exhibiting the effects 
of attrition. The tables of the lateral incisors are fully formed 
by the central cavity being surrounded by a line of worn surface. 
In the central incisors the cavity has become extremely shallow. 
With the development of the permanent incisors the perma- 
nent dentition of the horse is completed. 
