350 On the Teeth of the Ox, Sheep, aiid Pig, 
are thus brought into such a position that they partially overlap 
the nipple and exert the grasping power alluded to. It is pro- 
bable that by this peculiar condition of the tongue the teats of the 
sow are further protected against injury from these pointed teeth. 
Fi^-. -IC 
At one month important additions are made to the foetal teeth. 
The young animal about this time puts up four incisors, situated 
directly in the front of the jaws, two above and two below. 
These belong to the temporary set, and are miniature portraits 
of those teeth which will succeed them. 
In fig. 47, which gives a side view of the skull at a month 
old, two of these incisors are seen, one in either jaw — upper and 
lower. They arc marked M. i., denoting middle incisors. Al- 
though placed in front, these teeth are at first so little developed 
that no injury to tlie teat of the sow is likely to be done by them. 
Within a few weeks their increase of size enables the young ani- 
mal, by collecting its own food, to live comparatively independent 
of its dam, and hence young pigs can safely be weaned when 
about six or seven weeks old. 
Besides tlie cutting of the central incisors at this period, the 
young pig has now three temporary molars on either side of each 
jaw, T. M., fig. 47. The first of these in situation is generally less 
forward than the others, and not unfrequently at a month old has 
hardly cut the gum. Tlie third deciduous molar of the lower jaw 
agrees in form with tlie corresponding tooth of the ox and sliecp, 
having three 'semi-cylindrical lobes.' In the illustration it is 
seen to occupy a space greater than that possessed by the other 
two molars, and it will be observed how beautifully this increase 
* Fig. 4G. Skull of the pig at birth, seen on the left side. f. i. denote the 
foetal incisor, and f. t. the fcetal or temporary tush. This and all the suc- 
ceeding figures are of natural size. 
