444 



MAMMALIA. 



The normal number of teeth, in a horse with a so-called "full 



,,...,, , .3-3 1-1 3-3 3-3 



mouth IS lorty — namely, t- — -; c- ; pm-^ 



-1 



3—3' 3-3 



3—3' 1 

 — the canines being absent in the mare. 



Wolf-teeth are single -fauged teeth, sometimes present in 

 front of the back teeth, in the upper jaw generally. Both 

 " tushes " and wolf - teeth are per- 

 manent, but the latter are often soon 

 shed. 



The following may be taken as in- 

 dications of the age from birth to 

 thirty years old : — 



1. At birth. — The front milk-incisors 

 can be plainly seen under the 

 gums. 



2. At one month. — The front mUk- 

 incisors are through the gums, 

 the upper and lower ones meet- 

 ing, the middle ones just show. 



3. At five months. — The middle and 

 lower incisors meet and the 

 corner ones just show. 



4. A yearling. — The corner incisors 

 are through but do not yet 

 meet. 



5. A two-year-old. — Central enamel 

 of middle incisors of both jaws 

 now forms a complete ring. 



6. At two aiid. a half years. — Front milk-teeth fall out in 



upper jaw and become replaced by permanent ones. 



7. A three-year-old. — The four permanent incisors are nearly 



level (front incisors). 



8. At four years. — Middle milk - incisors are out and per- 



manent ones come. Tushes begin to show. 



9. At five years. — Permanent incisors all level. The central 



Fig. 211. — Transverse Sec- 

 tion OF Horse's Upper 

 Molar. (Cliauveau.) 



A, External cement ; b, ex- 

 ternal enamel ; c, dentine ; d, 

 internal enamel ; E, internal 

 crusta petrosa. 



Tlie structure of the molars 

 resembles that of incisors, but 

 is more complicated. The in- 

 ternal cavity is much diver- 

 ticulated and enveloped by 

 dentine. The enamel is placed 

 over it, and doubled in as in 

 the incisor. There is seen on 

 the worn tiible an external 

 covering of enamel and two 

 circles of central enamel sur- 

 rounding the two areas of in- 

 ternal cement. The cement 

 fills in the depressions on the 

 face of the crown, &c., and is 

 very abundant. 



