I30 



BRAINS OF RATS AND MEN 



and all other vertebrate brains. In the sturgeon much 

 larger and more important fiber systems ascend into 

 the endbrain from the hypothalamus than from the 



chdbncUn 



Jbetwcenbroin 



olfactori^ bulb 

 primitive endbrxxin 



*thalaTnuis 



isth"miis 



cerebellum' 



acousti CO -lateral area 



medulla oblongata 

 visceral sensori^ area 



Fig. 28. — Dorsal view of the brain of the sturgeon, Acipenser, natural 

 size. Membranous portions of the roof of the endbrain, betweenbrain, 

 and medulla oblongata have been removed, opening the ventricles. Re- 

 drawn from Johnston. 



thalamus. Since the hypothalamus is concerned large- 

 ly with smell, taste, and visceral adjustments, this 

 means that in this fish (as in fishes generally) the 

 primitive endbrain is largely devoted to correlation of 

 olfactory with gustatory and visceral activities. By 

 far the most important centers of adjustment of the 



