LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



white band of medullary substance, the fornix. Near the 

 junction of the thalamus and imd bi'uin it rises close to the 

 base of the brain, passes dorsad as the pillars of the fornix, 

 accompanies the margin of the hemisphere still farther, curves 

 around it into the temporal lobe, and ends in the apex of the 

 latter. 



The horizontal mass of transversely divided fibres above it 

 belongs to the corpus callosum. In its anterior part you will 

 distinguish the knee, in its posterior part the splenium, and be- 



, Jentjlui 



firflbrld or fornin. 



FIG. 32. 

 For explanation, see Fig. 31. 



tween the two the body. Between the fornix and the corpus 

 callosum lies the triangular field of the septum. Besides this, 

 you can see, just in front of and below the fornix. the anterior 

 commissure, and in the middle the commissura media, both, 

 of course, in cross-section. 



That portion of 'the hemisphere-wall which lies above the 

 corpus callosum is traversed by few and rather constant fissures, 

 First, parallel with the corpus callosum, is the sulcus calloso- 

 marginalis. Behind, it turns upward to the crest of the hemi- 

 sphere and terminates in a little indentation behind the posterior 



