EXPLANATION OF PLATE IV. 



DENTITION. 



1. Skull of man, showing the omnivorous teeth of the order Bimana. 



2. Tiger's head, showing the carnivorous teeth of the Cat family, (Felidae.) 



3. Dog's head, showing the carnivorous teeth of the Dog family, (Canidae.) 



4. Skull of a porcupine, showing the teeth of a gnawing animal, order 

 Rodentia. 



5. Horse's head, showing the vacancy for the bit between the front and 

 back teeth, which space corresponds with the angle of the lips. 



6. Hippopotamus' head, showing the canine teeth, (eye teeth,) developed 

 into enormous tusks, with a chisel like edge. 



7. Elephant's skull, showing the long, round, arched, pointed tusks or 

 incisors projecting from the upper jaw. 



8. A molar, grinding or back tooth of the elephant, of which there are 

 never more than two on each side of the upper and lower jaws of the 

 African elephant, and only one in a similar position in the Asiatic ele- 

 phant. 



9. Mastodon's tooth, showing the conical points whence the animal derives 

 its name. For the tusks of the mammoth, see the Chart. 



10. Skull of a cow, showing the dentition of a cud chewing animal, order 



Ruminantia. 



11. Porpoise skull, showing how the numerous teeth interlock with one 

 another when the jaws are closed. 



