Rural vSchool Leaflet 



1167 



Sheep have two sets of teeth; first, a temporary set, called the decid- 

 uous teeth, meaning those that fall out; and later, a permanent set. 

 We will study in detail the incisors, or front teeth, only. The temporary 

 incisors come into the mouth within three weeks after birth, and are eight 

 in number. At the end of thirteen to fifteen months after birth, the 

 middle pair of these temporary incisors will have been replaced by a 

 pair of permanent incisors; at the end of two years or a little more, the 

 next two — called the inner middles — will be in place; and then in another 

 year and a half, the last two permanent incisors will have come in, and 



Middle wool sheep in England 



the sheep will be four and one half to five years of age. The molars, or 

 grinders, or back teeth as they are called, come in somewhat regular order, 

 filling the back parts of the jaws in about the same time; all the molars 

 being in place and all in wear at the end of five years. 



The lips of the sheep are peculiar in their construction and take an 

 important part in the gathering of the food. The upper lip has no muzzle 

 such as is seen on cattle (the broad patch on the upper lip which is pro- 

 vided with an excretory apparatus, and which we may recognize by the 

 beads of perspiration that stand on a cow's upper lip in hot weather). 

 Instead, the sheep's upper lip is divided in the middle by a fissure, which 

 allows either part to be moved independently. This construction of 



