90 



NATURAL HISTORY OF THE HORSE. 



TKETH AT TUTELVE MONTHS. 



almost level, and the corners are becoming so. The mark ia 

 the two middle teeth is wide and faint, in the next two teeth 



it is longer, darker, and more 

 narrow. In the corner teeth it 

 is longest, darkest, and most 

 narrow. 



The back teeth, or grinders, 

 will not guide us far in ascer- 

 taining the age of the animal, 

 for we cannot easily inspect 

 them ; but there are some inter- 

 esting particulars connected 

 with them. The foal is born with two grinders in each jaw, 

 above and below, or they appear within two or three days after 

 birth. Before the expiration of the month they are succeeded 

 by a third, more backward. The crowns of the grinders are 

 entirely covered with enamel on the tops and sides, but attrition 

 soon wears it away from the top, and there remains a compound 

 surface of alternate layers of crusta petrosa, enamel, and 

 ivory, which are employed in grinding down the hardest por- 

 tions of the food. Nature has, therefore, made an additional 

 provision for their strength and endur- 

 ance The annexed cut represents a 

 grinder sawed across. The five dark 

 spots represent bony matter; the parts 

 covered with lines enamel, and the white 

 X GBiNDER SAWED ACROSS, spaccs Si stvoug bouy ccmcut uniting the 

 other portions of the teeth. 



At the completion of the first year a fourth grinder usually 

 comes up, and the yearling has then, or soon afterwards, six 



