150 Wisconsin Academy of Sciences, Arts, and Letters. 



I |May it not be true that the absence of upper incisors in the ru- 

 minants, and the total want of front teeth in the edentata, are the 

 result of long ages of disuse, accompanied with the almost con- 

 stant friction and presure against them, which might injure and 

 ultimately destroy the germs of the useless teeth, until their 

 absence becomes an hereditary peculiarity, as a final result ? 



