368 



LATERAL VENTRICLES. 



and outwards in the anterior lobe ; the middle cornu descends into 

 the middle lobe; and the posterior cornu passes backwards in the 

 posterior lobe, converging towards its fellow of the opposite side. 

 The central cavity is triangular in its form, being bounded above 

 (roof) by the corpus callosum ; internally by the septum lucidum, 

 which separates it from the opposite ventricle; and below (floor) by 

 the following parts, taken in their order of position from before 

 backwards: 



Corpus striatum, 



Tenia semicircularis, 



Thalamus opticus, 



Choroid plexus, 



Corpus fimbriatura, 



Fornix. 



Fig. 124 * 



* 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 majusi. The sur- 

 face is seen to be studded with the small vascular points puncta vasculosa ; and sur- 

 rounded by a narrow margin which represents the gray substance. 2. A small portion 

 of the anterior extremity of the corpus callosum. 3. Its posterior boundary ; the inter- 

 mediate 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 inter- 

 space between its layers the fifth ventricle. 5. The anterior cornu of one side. 6. 

 The commencement of the middle cornu. 7. The posterior cornu. 8. The corpus 

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

 striata 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 communi- 

 cates with that of the opposite ventricle through the foramen of Munro ; a bristle is 

 passed through this opening, and its extremities are seen resting on the corpus striatum 

 at each side. The figure 11 rests upon the edge of the fornix, upon that part of it 

 which is called the corpus fimbriatum. 12. The fornix. 13. The commencement of 

 the hippocampus major descending into the middle cornu. The rounded oblong body 

 in the posterior cornu of the lateral ventricle, directly behind the figure 13, is the hip- 

 pocampus minor. 



