350 THE MORPHOGENESIS OF THE CENTRAL NERVOUS SYSTEM 



cerebral wall thickens rapidly owing to the development of (i) the fibers from the 

 thalamus and corpus striatum; (2) of endogenous fibers from the neuroblasts of 

 the cortex. The fibers form a white inner medullary layer surrounded by the gray 

 cortex. As the cerebral wall increases in thickness the size of the lateral ventricle 

 becomes relatively less, its lateral diameter especially being decreased. For the 

 special differentiation of the cerebral cortex in different regions the student is 

 referred to text-books on neurology. 



