Anatomy of the Brain. 565 



fibres ( 22 ) are received at this point from the locus niger of the crura 

 cerebri ( 10 ). The band then runs forward toward the anterior commis- 

 sure (15), which apparently, but not really, connects the two corpora 

 striata, before reaching which it receives fibres from the base of the 

 brain ( 2 ). Then it bends upward against the anterior commissure with 

 which it is connected, and forms what are called the anterior columns, 



FIG. 275. Section of Brain to show the relations of the Fornix partly diagramatic. 

 C C. Corpus callosum. 10. Inner end of crus cerebri. 



F Body of the Fornix. 



11. Fourth ventricle. 



F. Velum interpositum. 12. One of the corpora quadrigemina. 



1. Chordas longitudinales longitudinal 13. Pineal gland, 

 fibres above the corpus callosum. 



2 2. Nerve fibres from the chordae, cor- 

 pus callosum and fornix to the front and 

 base of brain. 



3. Same to posterior lobe. 



4. Septum lucidum in same position as 

 5th ventricle. 



5. Optic Thalamus. 



6. Anterior pillar of Fornix. 



7. Posterior commissure. 



8. Medulla oblongata broken off at top. 



9. Cerebellum. 



34. Middle or soft commissure. 



15. Anterior commissure. 



16. Fibres from Fornix covering hippo- 

 campus major. 



17. Fibres from Fornix covering thepes, 

 or foot, of the hippocampus major. 



18. Third nerve. 



19. Corpus Albicans. 



20. Valve of Vieussens in profile. 



21. Aqueduct of Sylvius. 



22. Fibres from the Crus to the Fornix 



or pillars of the fornix ( 6 ). Thence it bends upward and backward 

 over the foramen of munro. Here it receives the tenia semicircularis 

 and the peduncles of the pineal gland. Then receiving on its outside 

 the insertion of the inferior edge of the septum lucidum ( 4 ), the fornix 

 passes over the inner ends of the cornua ammonis and the optic thalami, 

 and flattening itself against the underside of the corpus callosum it 

 forms what is called the body of the fornix ( F ). A part of its fibres 

 on the median line become confounded with the body of the corpus cal- 

 losum. At the back part of the brain the fornix again divides into the 

 posterior pillars, one leaf from each side passing down into the descend- 

 ing cornu in company with the hippocampus major, or cornu ammonis, 

 and forming over it a layer of white medullary matter. On the con- 

 cave border of each descending cornu, this white substance is thickened 



