124 ANATOMY. 



behind the corpora striata. Each thalamus opticus is divided into an anterioi 

 tubercle seen in the lateral ventricle, and a posterior tubercle beneath the 

 fornix. 



Corpora Quadrigemina, or Optic Lobes (2 nates and 2 testes), lie beneath the 

 posterior lobes, near the union of the cerebrum and cerebellum. They form 

 two single ganglia for vision. [Described under Meso-cephalon.] 



Tuber Annulare, a ganglion in the substance of the pons Varolii, the seat of 

 indistinct sensation probably. 



Name the Commissures of the Brain. These connecting bands number 19 

 in all, of which 10 are longitudinal, and 9 transverse in direction, viz. 

 Longitudinal Commissures. Transverse Commissures. 



Olfactory Tracts. Anterior Commissure of 3d ventricle. 



Taenia Semicircularis. Middle Commissure of 3d ventricle. 



Crura Cerebri. Posterior Commissure of 3d ventricle. 



Processes e Cerebello ad Testes. Corpus Callosum. 



Peduncles of the Pineal Gland. Optic Commissure. 



Fornix. Pons Varolii. 



Infundibulum. Fornix, is a transverse commissure as 

 Lamina Cinerea. well as a longitudinal one. 



Gyrus Fornicatus. Posterior Medullary Velum. 



Fasciculus Unciformis. Valve of Vieussens. 



What are the Ventricles of the Brain ? They are 5 cavities, each of which 

 is situated as follows : 



Two Lateral Ventricles, within the substance of the hemispheres. 



Third Ventricle, between the optic thalami, on the base of the brain. 



Fourth Ventricle, between the cerebellum and the medulla oblongata. 



Fifth Ventricle, between the two lateral, in the septum lucidum. 



Ventricle of the Corpus Callosum, so called, is merely the space between the 

 upper surface of that commissure and the margins of the hemispheres 

 above (Jabia cerebri}. 



The Foramina of Monroe connect the two lateral ventricles with the 3d ; the 

 Iter e Tertio ad Quartam Ventriculum, or aqueduct of Sylvius, connects the 

 3d with the 4th. 



Describe and bound the Lateral Ventricles. They each have 3 Cornua, the 

 anterior, middle, and posterior, and are bounded as follows: 



Roof, the corpus callosum. 



Floor, the corpus striatum, tsenia semicircularis or horny band of Tarinus, 

 optic thalamus, choroid plexus, corpus fimbriatum, and the fornix. 



Internally, the septum lucidum. 



Externally, behind and in front, the brain substance. 



