182 AGE OF THE DOMESTIC ANIMALS. 



As age advances the teeth of the sheep are worn to stumps ; 

 they become black and loose in their alveolar cavities. 



In the old animals the face wrinkles, the lips become thick, 

 and the muzzle, which was fine and pointed in the lamb, be- 

 comes enlarged and broad. Sometimes in old sheep, but more 

 frequently in old goats, the incisors attain a great length ; the 

 incisive arch is, however, in these cases usually broken and 

 irregular. 



DETERMINATION OF AGE BY THE HORNS. 



The horns of the ovine and caprine races are variable 

 ornaments. Some races have horns, some do not ; in some 

 races the male has horns and the female none, while in the 

 others the female has very small, aborted apologies for them. In 

 the long-wooled English sheep the horns are absent ; the 

 merinos originally had the magnificent typical " ram's horn," 

 which has become a descriptive of shape, but domestication has 

 gradually reduced them in size, and in some families they abort 

 entirely. 



The horn of the sheep grows up, out, back, and gradually 

 turns on a central axis, according to its length, in the form of a 

 conical corkscrew. The horn of the goat grows up, back, and 

 slightly outward. 



In structure and growth the horns of the sheep and goat 

 are like those of the ox. The liorn of the sheep is flat on its 

 inferior surface and convex from side to side on its superior 

 surface ; it is divided transversely by ridges ; the interspaces have 

 longitudinal scaly ridges and gutters. 



The horns appear about fifteen days after birth, attain their 

 greater growth during the first year, and cease growing after 

 four years. If the animal is castrated the growth of the horn 

 lessens, whereas in the ox castration stimulates the growth. 



The epidermic covering, which extends from the skin on 

 the appearance of the horn, dries and scales off in six weeks to 

 two months, leaving a roughened, scaly surface. The size and 



