PLATE 2 



EXPLANATION OF FIGlIRKh 



21 Median view of the forebrain of an S.8 mm. embryo of Chrysemys margi- 

 nata. Embryo 1433. H.E.C. X 40. 



22 Lateral view of the forebrain of an 8.8 mm. embryo of Chrysemys mar- 

 ginata. Embryo 1433. H.E.C. X 40. Lateral hemispheio wall I'omoved. 



534 



