102 



THE TEETH. 



bones. On account of differences in the shape of their 

 crowns, and in their uses, the teeth are divided into in- 

 cisors, canines, bicuspids, and molars. The incisors (Fig. 25) 

 have sharp chisel-shaped edges and are adapted for cut- 

 ting our food. The canines (Fig. 26) or eye-teeth are 



FIG. 25. 



FIG. 26. 



FIG. 27. 



FIG. 28. 



FIG. 25. An incisor tooth. 



FIG. 26. A canine or eye tooth. 



FIG. 27. A bicuspid tooth seen from its outer side ; the inner cusp is accord- 

 not visible. 

 IG. 28. A molar tooth. 



pointed and serve the same purpose: they are very long 

 and sharp in dogs and cats, and are useful to these ani- 

 mals in holding their prey. The molars (Fig. 28) have 

 broad rough ends to their crowns and are suited to grind 

 and crush. The bicuspids (Fig. 27) are like the molars 

 but not so large. 



9. Arrangement of the Teeth in the Jaws. In the 

 milk-set, there are twenty teeth, ten in each jaw. Begin- 

 ning in the middle line and going back, we find in order, 

 on each side, two incisors, one canine, two molars. 



The permanent teeth number sixteen in each jaw. 

 Beginning at the middle line, we find successively two 

 incisors, one canine, two bicuspids, and three molars, in 

 each half of each jaw. The incisors and canines take 

 the places of the milk-teeth of the same names. The 



9. Arrangement of milk-teeth. Of permanent teeth. Which ones 

 are added as the jaw grows larger ? What of the wisdom-teeth ? 



