204 



AGE OF THE DOMESTIC ANIMALS. 



The upper arch is shghtly larger than the lower, and the corre- 

 sponding teeth of each jaw are not directly opposite each other, 

 but come in contact with two opposite teeth, so that, if one is 

 lost, the oi)posing tooth still finds a resisting surface, and has 

 not the tendency to displacement found in the herbivora under 

 similar circumstances. 



The incisors, four in each jaw, are known as the central 

 and lateral incisors; they have a single root and a sharp, 

 wedge-shaped crown, divided from the former by a distinct 

 neck. 



Fig. 186. 



Upper and lower teeth of one-half of the dental arches in each jaw ; two incisors. 



one tush, two premolars, three molars, in each. 



The tushes, called cuspids {cuspis^ a spear), from their 

 pointed crowns, are two in number in each jaw. These teeth 

 are also called canine teeth ; those of the upper jaw^ are called 

 eye teeth, and those of the lower jaw stomach teeth. 



Tlie premolars, two in each side of jaw, are called bicus- 

 pids (bicuspidati, two spear-points), from the two eminences on 

 their crowns. 



The molars, six in each jaw, are known as the first, second, 

 and third, or as the six-year molars, twelve-year molars, and the 

 wisdom teeth {dens sapientici), from the fact that the two first 

 appear at six and twelve years, and the last not until adult age, 

 when wisdom is supposed to come. 



