330 On the Teeth of the Ox, Sheep, and Pig, 
molar and the temporary is so well shown in the illustrations, 
that any special description of this tooth beyond that which has 
been already given, is rendered unnecessary. 
From the preceding remarks respecting the molar teeth, we find 
that, during some of the periods most difficult for correct ascer- 
tainment of the age of an ox by his incisors, the molars afford the 
very assistance wlilch is required, so that, if these teeth as well as 
the incisors are carefully studied, few errors can be made by an 
investigator. The importance of the subject may justify my re- 
peating, that the fourth molar is cut at about six months, the fifth 
at fifteen, and the sixth at two years, and that each attains its level 
in the jaw in three months after these respective dates : that at 
two years and a half the two anterior temporary molars give place 
to the permanent, as likewise does the third before the animal 
has attained the third year of his age. 
To return again to the incisors. At two years and three 
quarters, the third pair of incisors is frequently cut, and that 
date is therefore assigned to these teeth in the early table. The 
variations in the putting up of tlie third pair being similar to 
the others, 1 have selected for my illustration the mouth of a three- 
ycars-old animal, fig. 32. In this engraving these teeth are marked 
Fig. 32 * 
* Fig. 32. Front part of the lower jaw at three years, showing the third pair 
of permanent incisors in situ. Natural size. 
