130 



THE STRUCTURE OF THE HORSE 



be expected to have milk predecessors, especially as 

 such are frequently absent in other animals in which 

 these teeth are fairly well developed. 



The functional milk molars are three in number, 

 corresponding in succession with the three functional 

 premolars of the permanent set. The middle one 

 resembles the intermediate permanent molars, but the 

 first and third have their extremities somewhat narrowed, 

 so that the grinding-surface of the whole block presents 

 a representation on a smaller scale of that of the perma- 

 nent set. The crowns are comparatively short, and 

 distinct roots are formed by the time the growth of the 

 tooth is complete. As the permanent teeth rise up 

 below them these roots are absorbed, and nothing 

 remains but the worn base of the crown, which is finally 

 cast off as its successor becomes fitted to take its 

 place. 



Time of Appearance and Order of Succession of the 

 Teeth. — The eruption or cutting through the gums of 

 the temporary teeth commences at about the time of 

 birth, and is complete before the end of the first year, 

 when the young animal has its full set of twenty-four 

 teeth, three incisors and three molars above and below 

 on each side of each jaw. The upper teeth, as a rule, 

 appear somewhat earlier than those of the lower jaw. 

 Within a very few days after birth the central incisors 

 make their appearance, and by the end of the second 



