798 



THE NERVOUS SYSTEM 



Fig. 626. — Median Sagittal Section through Embryonic Human Brain at End of First 



Month. (After His.) 



(Showing the localities of origin of the derivatives of the three primary vesicles named in outline 



on p. 797.) 



^/^ ^^^ \Dieiicepli'iW>ii ^-^ ^ ^z. 



///^. \ V, [^ . ..,^ 



> ) #-Telencephalnii -. / J J \\\ ^ niz 



Y\z y,, y^' /"^ 



'i * II ~ .^ ^ 



Hypophysis (anterior side) - -^;:r_-'' / / ~ ^^^^-t^^ 



Ventral zone — ! ,' 



i\ ■•-,/ii /' V' 



Dorsal zone - - . rJ-'l .. ' ■ "^ "* 



fe*^ spinalis 



Fig. 627. — Sagittal Section of Brain of Human Embryo of the Third Month. (After His) 



(Reference numerals correspond with those of fig. 626 and those after names of parts in outline 



on p. 797.) 



Cervical 

 flexure 



