ANATOMY AND SUBDIVISION OF NERVOUS SYSTEM 121 



ment and Fig. 51 the adult brain in median section. The exter- 

 nal form of the adult brain is illustrated also in Figs. 52, 53, 54. 



TBAXS- 

 TEKSB 

 OCCIPI- 

 TAL SOL- 



cvs 



Fig. 54. View of the left side of the adult human brain. Some of the 

 principal sulci and gyri are named. The lateral cerebral fissure (sylvian 

 fissure) is not named; it lies immediately above the gyrus temporalis supe- 

 rior. (After Toldt, from Morris' Anatomy.) 



The following table summarizes the relations of the subdivis- 

 ions of the brain (the ventricles of some of them being added in 

 parentheses), to which a few comments are here added: 



Rhombencephalon, rhombic brain (fourth ventricle). 

 Myelencephalon, medulla oblongata. 

 Metencephalon. 

 Cerebellum. 

 Pons. 



Isthmus rhombencephali. 

 Cerebrum. 



Mesencephalon, midbrain or corpora quadrigemina and cerebral peduncles 



(aqueduct of Sylvius). 

 Prosencephalon, forebrain. 



Diencephalon, betweenbrain (third ventricle). 

 Hypothalamus. 

 Thalamus. 

 Metathalamus. 

 Epithalamus. 

 Telencephalon, endbrain. 

 Pars optica hypothalami. 

 Hemisphseria, cerebral hemispheres (lateral ventricles). 



