CORPORA QUADRIGEMINA 

 PINEAL ORGAN 

 POST COMMISSURE 

 THIRD VENTRICLE^! 

 MAS. INTERMEDIA^f ;.:} 

 CHORIOIDx^!, 'I i - : ! 

 CORPUS 

 CALLOSUM 



FORNIX 



tegrative Systems 



225 



INFUNDIBULUM 



POSTERIORI 

 " ^ANTERIOR 



LOBE OF PITUITARY 



Fig. 190. A median section of the human brain-stem, showing the relations of 

 the pituitary gland. (After Sobotta. Courtesy, Neal and Rand: "Chordate Anat- 

 omy," Philadelphia, The Blakiston Company.) 



NTERMEDIATE LOBE 



'HYPOPHYSIAL DUCT 

 B. PETROMYZON 



A. MYX1NE 



C. HEPTANCHUS 



PARS TUBERAL 



.POSTERIOR LOBE 



INFUNDIBULUM 



At\ ^ POSTI 



-ANTERIOR LOBE- 



INRINDIBULUM 



POSTERIOR LOBE' 

 F. HOMO 



Fig. 191. A series of diagrams showing conditions in six different vertebrates. 

 The series suggests possible stages in the evolution of the pituitary gland. The 

 complexity of origin of this gland is correlated with the complexity of its endocrinal 

 functions. The posterior lobe is cross-hatched, intermediate lobe stippled, anterior 

 (hypophyseal) lobe piebald, and the pars tuberalis solid black. (Redrawn from 

 Oppel, after Stendell. Courtesy, Neal and Rand: "Chordate Anatomy," Phila- 

 delphia, The Blakiston Company.) 



