THE TEETH OF VERTEBRATES 77 



cusps. Such an example is seen in the armadillo 

 and the teeth may be said to represent the original 

 protocone and protoconid (Fig. 26). 



Fig. 26. — Skull of Armadillo (Euphractus minutus) , showing occlu- 

 sion of rows of teeth. 



In the occlusion of cusps, which is the type of 

 occlusion found in higher mammals, we find the 

 teeth have evolved so as to present a tooth with 



Fig. 27. — Skull of Mountain Lion, showing occlusion of cusps. 



many cusps which is so arranged as to occlude 

 with the cusps of the opposing tooth. This gives 

 a tooth which has a great amount of grinding sur- 

 face (Fig. 27), 



