MAMMALS 



305 



tant as a source of food, but nearly all are now so reduced in 

 numbers that they are little hunted except for sport. The 

 domesticated mammals, the most important of which belong 

 to this order, are discussed in Chapter XXVI. 



The order Glires, the rodents, or gnawers, is the largest of the 

 orders of mammals, and includes the rabbits, porcupines, 



FIG. 133. A buffalo, Bison bison, killed for its skin and tongue, on the 

 plains of western Kansas, forty years ago. (Photograph by J. L. Knight.) 



gophers, chipmunks, beavers, squirrels, rats and mice. The 

 special arrangement and character of the teeth are character- 

 istic of this order. There are no canines, a toothless space 

 being left between the incisors and molars on each side. There 

 are only two incisor teeth in each jaw (rarely four in the upper 

 jaw). These teeth grow continuously and are kept sharp 

 and of uniform length by the gnawing on hard substances and 



