90 



AGE OF HOESES. 



the incisor teeth in their sockets, when they become short 

 with age, the lining membrane {j[>eriosteu7n) of the sockets 

 secretes, around the stumps, bone, in the form of cement, 

 which serves to keep these stumps in their place, and 

 to increase the area of their cutting surface (see Fig. 19). 

 Bates of ieetliing. — I may mention that, as a rule, the 

 incisors of the upper jaw make their appearance sooner 

 than those in the lower jaw. At birth, the front milk 

 incisors show themselves under the gum (see PL I.). 



Incisors. 



Date of eruption through gum. 



Front milk . . 

 Middle „ . . 

 Corner „ 

 Front permanent 

 M.ddle „ 

 Corner „ 



About a week after birth 

 SOto^Odaj-s „ „ 

 8 to 10 mouths „ „ 

 2h years alter birth . 



'^■i J) j> jj 



^■2 5J i1 J5 • 



See Plate I. 

 „ II. 

 „ IV. 

 „ VII. 

 „ IX. 

 „ XL 



The time at which the tuahes make their appearance 

 varies considerably. It may, however, be approximately 

 fixed at four years old. 



As there is some divergence of opinion among 

 authorities, as regards the dentition of the molars, I shall 

 give, in the following table, the views respectively held 

 by MM. Chauveau and Lecellier. According to the 

 latter, the milk molars of the lower jaw always fall out 

 before their fellows of the upper jaw. I may mention 

 that at, or shortly after birth, the foal has twelve milk 



