THE SENSE-ORGANS 397 



it is probably concerned with smelling the food in the mouth, 

 with which they are in communication. In some forms, in- 

 cluding man, Jacobson's organs disappear. In the snakes 

 they are very highly developed, and the tips of the forked 

 tongue enter their openings in the roof of the mouth. Sub- 

 stances gathered on the tongue when protruded are thus 

 placed in contact with the sense-organ. 



Literature 



von Buddenbrock, W. Grundriss der vergleichenden Physiologic. Vol. i. 



Borntraeger, Berlin, 1924. 

 Herrick, C. Judson. An Introduction to Neurology. Saunders Co., 



Philadelphia and London, 1922. 



