588 MANUAL OF MODERN FARRIERY. 



also termed the incisors, but is furnished with eight cutting- 

 teeth in the lower jaw. 



At two years of age two of these drop out, and are 

 replaced by other two. At three years old four of them are 

 renewed, and the others at the age of four years. 



The teeth undergo considerable changes between the first 

 and eighth years, which we have delineated in plate xiii., so 

 as to enable persons to judge of the age of sheep by their 

 dentition. 



Fig. 5 exhibits the appearance of the teeth at one year 

 old. Their cutting, or outer edges form a crescent-shaped 

 line, the teeth being nearly all of a similar breadth, almost 

 flat, and very smooth on their outer surface, and consider- 

 ably concave internally. 



Fig. 6 shows their aspect at two years of age, in which 

 the two central teeth are considerably broader than the 

 others, with the cutting edge not nearly so much arcuated 

 as at two years. 



Fig. 7 represents the structure of the teeth at three years, 

 from which it will be observed that the four central ones 

 are considerably broader and longer than the other two on 

 each side, which rather suddenly sliorten, the external teeth 

 being shortest and narrowest : the cutting edge of the four 

 central ones is but slightly curved. 



Fig. 8 characterises the teeth at four years, and shows 

 that the six central ones are nearly of uniform breadth and 

 length ; their cutting edge being but very slightly curved, 

 the external tooth on each side being materially shorter 

 than the others. The wdiole of the teeth are much stronger 

 than in any of the preceding years. 



Fig. 9 shows the structure of the teeth on the fifth year. 

 It will be observed that the whole eight teeth are nearly 

 straight on their cutting margin, and that there is but a 



