170 



ANATOMY OF THE CENTRAL NEEVOTTS SYSTEM. 



a smooth surface, but in several species one recognizes that it experiences an 

 increase in area through folding. In mammals this folding reaches the ex- 

 tent of a complete rolling in of the whole cortex, at least in adults, while in 

 the embryonic state the relations are the same as in reptiles, where the struct- 

 ure first made its appearance (see Fig. 119). 



This rolled in portion of the cortex that always receives a bundle from 



Fig. 118. — Frontal section through a liemisphere of the giant turtle: Chelone midas. 



the olfactory apparatus has long since been designated as the Cornu 

 Ammonis. 



The investigation of the amphibian brain makes it very probable that 

 exactly the corresponding region of the mantle-wall receives olfactory con- 

 nections. 



Broca, and later Zuckerkandl, demonstrated, after numerous compari- 

 sons, that in mammals the extension of Ammon's horn and the cortex lying 

 anterior to it under the limbic fissure is completely dependent upon the 



