VENTRICLES. 1NFUNDIBULUM. 



587 



brum, viz. the middle commissure of the third ventricle 

 formed by the union of the cineritious substance of the two tha- 

 lami ; the anterior commissure of the third ventricle, which 

 passes across between the corpora striata and the neighbor- 

 ing parts of the cerebrum, in front of the anterior crura of the 

 fornix, and which sends some filaments which arch forwards 

 .Fig. 225.* 



4 f ? 



c 



7 11910 E 



to the origin of the olfactory nerve ; the superior longitudinal 

 commissure described by Mayo as running along the sides of 

 the longitudinal fissure above the corpus callosum, to connect 



* Fig. 225, is a vertical section of the cerebrum, cerebellum and medulla 

 oblongata. A, Anterior lobe of the brain. B, Middle lobe. C. Posterior lobe. 

 D, Cerebellum. E, Medulla spinalis. Jf, Medulla oblongata. JT, Pons varolii. 

 L, Crus cerebri. /, Section of the corpus callosum, which is situated at the 

 bottom of the fissure, separating the two hemispheres of the brain, g, Optic 

 lhalamus, of which the back part only is seen. The corpus striatum is placed 

 in front of it, though not seen in this figure, and at the bottom of the dark space 

 which forms the lateral ventricle. Below the thalamus is seen the section of 

 the tubercula quadrigemina, (the superior eminences of which are called the 

 nates, the lower, testes,) and below that again the valve of Vieussens ; which 

 arises from the medullary layer of the central portion of the cerebellum, D. 

 Below the corpus striatum is the lateral ventricle. Between the optic thalamus 

 and the cms, is seen the third ventricle j (the fornix which separates these two 



