TURNER: RECONSTRUCTION OF LIZARD BRAIN. 115 



The optic thalami shows a tendency to elongate anteriorly. 

 The hypophysis is pulled back from a position directly beneath 

 the infundibulum until it assumes a position behind and a level 

 with the infundibulum. 



The point of attachment of the sixth cranial nerve serves as 

 an excellent mark to follow in tracing the change of position 

 of the medulla. In the development to the adult stage the loop 

 in the medulla becomes straightened out and the point of at- 

 tachment of the sixth cranial nerve is pulled back from a posi- 

 tion beneath the optic thalami to occupy one posterior to the 

 optic lobes. 



The spinal cord comes to lie in a horizontal plane, whereas 

 in the embryo it bends sharply downward from its junction 

 with the brain. 



The cerebellum, which in the embryo is small and unde- 

 veloped and appears "pinched" between the optic lobes and 

 the spinal cord, develops and takes a dorsal rather than a 

 posterior position in reference to the rest of the brain. 



The pineal apparatus extends forward from its attachment 

 in the adult stage, while in the embryonic stage its extends 

 backward. From the stage modeled to the adult stage it 

 must revolve forward through an angle of about 110 degrees. 



2 - Univ. Sci. Bull., Vol. IX, No. 9. 



