General Management of the Flock. 29 



teeth we will find eight of them on its lower jaw in 

 front, but none on the upper jaw. In the illustra- 

 tion are shown views of the entire skulls and of 

 the lower jaws of sheep of different ages. The 

 lamb's skull at the left shows its full set of first or 

 "milk" teeth. These milk teeth are uniform in size 

 and shape, and are rather narrow. After the lamb 

 has reached the age of from twelve to fifteen 

 months the central pair of milk teeth drop out, 

 and a much larger pair of permanent teeth, or in- 

 cisors, take their place. The second view shows 

 the front teeth of a sheep of this age. At the age of 

 two years another pair of milk teeth, one on each 

 side of the first pair, will be replaced by another 

 pair of permanent ones, as is shown in the third 

 view. A year later the third pair of permanent 

 teeth will appear, and only one pair of milk teeth 

 will be left, as is shown in. the fourth jaw. At 

 length when the sheep is about four years old, the 

 whole set of milk teeth will have been replaced 

 by a full permanent set, as is shown in the last 

 view. 



We often find that the changes of teeth are 

 somewhat irregular. For instance, the writer has 

 seen rare cases where sheep did not change the 

 first pair of teeth until they were eighteen and in 

 one case nineteen months old, and then shortly 

 after the first change had occurred the second took 



