66 COMPARATIVE DENTAL ANATOMY 



Bunodont. Crown supporting tubercles (as in 

 Man, Carnivora, Mastodon, etc.). 



Lophodont. Summit of crown with transverse 

 or longitudinal folds (as in Herbivora). 



The Evolution of Teeth. The molar teeth pre- 

 sent great varieties among mammals, but all have 

 been derived in some manner from the primitive 

 cone. All investigators are not agreed as to the 

 exact manner of the evolution of the molars. In 

 studying the evolution of the teeth, we are forced 

 to gain our knowledge from three sources; viz., 

 anatomy, embryology and paleontology. Each 

 one of these sciences cast some light upon the 

 evolution of the teeth and these sciences all go to 

 prove that the teeth have evolved from the simple 

 cone. 



From the study of paleontology, different in- 

 vestigators do not agree as to the exact manner 

 of the evolution of the molars. All agree that 

 the molars have started from a single cone, but 

 they do not agree as to the exact detail. From 

 the study of the teeth of fossils, it seems to the 

 writer that it may be possible that all of the molar 

 teeth did not evolve in the same manner, but have 

 been the result of radiation. By radiation in bi- 

 ology is meant that the plant or animals of a cer- 

 tain class all begin from a common center and 

 branch off in different directions until we have 

 many plants that resemble each other but very 



