CRANIUM OF THE SHEEP. 



343 



The ruminants, who principally live on green leaves or tender 

 shoots, naturally required a very different dentition from that 



Skull of the Sheep, viewed laterally. 



of the rodents, who have been specially appointed to devour the 

 hardest substances, generally living upon the wood and bark of 

 trees, as well as upon nuts and other shelled fruits. Here the 

 lower jaw only is provided with six shovel-formed incisors, pro- 

 jecting almost horizontally, and pressing against the upper jaw,- 



Base of the Cranium of the Sheep. 



Lower Jaw of the Sheep. 



which in nearly all cases is destitute of incisor teeth ; their place 

 being supplied by a kind of callous pad, a formation exceedingly 



