THALAMUS NERVI OPTICl. FORNIX. 



383 



other ; and this adhesion is called the soft commissure, (commis- 



sura 7nolUs.) 



The corpora striata, and the thalami nervorum opticorum 

 Fig. 187.* join each other at the exterior 



sides of the thalami : where 

 they are in contact, there is 

 the appearance of a narrow 

 medullary band, which con- 

 tinues during the whole ex- 

 tent of their connexion : it 

 has been called, by some, 

 tenia semicircularis, from its 

 form ; by others, centrum ge- 

 minum semicirculare, and tenia 

 striata. 



— A vein of considerable size 

 runs along the upper surface 

 of the tenia, formed from the 

 veins which emerge from the 



corpus striatum and thalamus and which vein empties into the 



vena galeni of the same side. 



* The lateral ventricles of the cerebrum. 1, 1. The two hemispheres cut 

 down to a level with the corpus callosum so as to constitute the centrum ovale 

 majus. The surface is seen to be studded with the small vascular points — 

 puncta vasculosa ; and surrounded by a narrow margin which represents the 

 grey substance. 2. A small portion of the anterior extremity of the corpus 

 callosum. 3. Its posterior boundary ; the intermediate portion forming the 

 roof of the lateral ventricles has been removed so as to completely expose those 

 cavities, 4. A part of the septum lucidum, showing an interspace between its 

 layers — the fifth ventricle. 5. The anterior cornu of one side. 6. The com- 

 mencement of the middle cornu. 7. The posterior cornu. 8. The corpus stria- 

 tum of one ventricle. 9. The tenia semicircularis covered by the vena corporis 

 striati and tenia Tarini. 10. A small part of the thalamus opticus. 11. The 

 dark fringe-like body to the left of the figure is the choroid plexus. This 

 plexus is continuous by a small process of it which passes through the foramen 

 of Monro, with the cavity of the third ventricle. A bristle is passed across, 

 through the two foramina of Monro, the extremities of which rest on the cor- 

 pus striatum of each side. Figure 11 rests upon the side of the fornix ; this 

 side portion, terminates in the posterior crus of the fornix, which runs down 

 the middle cornu of the lateral ventricle by the side of the hippocampus major 

 and is (here caWed corpus Ji7)ibriatum. 12. The fornix. 13. The commencement 

 of the hippocampus major descending into the middle cornua. The rounded 

 oblong body in the posterior cornua of the lateral ventricle directly behind fig. 

 13 is the Ergot, or hippocampus minor. 



