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 opposing 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 teetli, 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 firsts second^ 

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

 wisdom teeth (dens sapientia), 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. 



