ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 



633 



They thus form a large column upon each side, known as the middle 

 cerebellar peduncles. 



2. The posterior face forms part of the floor of the fourth ven- 



Fig. 245. The Base of the Brain. The Left Lobus Temporalis is 

 in Part Represented as Transparent in Order that the Entire Course of 

 the Optic Tract Might be Seen. (EDINGEB.) 



tricle, and is continuous with the corresponding face of the medulla 

 )blongata. It forms a triangle whose apex, turned upward, is placed 

 it the level of the lower orifice of the aqueduct of Sylvius. The 

 sides of this triangle are formed by the superior cerebellar peduncles. 



