340 



ANATOMY IN A NUTSHELL. 



7. Fornix, which is a longitudinal commissure also. 



8. Posterior or inferior medullary velum. 



9. Valve of Vieussens, anterior or superior medullary velum. 

 The following are the principal longitudinal commissures: 



1. Olfactory tracts. 



2. Taenia semicircularis. 



3. Crura cerebri. 



4. Processus-e-cerebello ad testes. 



5. Peduncles of the pineal gland. 



6. Fornix. 



7. Infundibuluni. 



8. Lamina Cinerea. 

 0. Gyrus fornicatus. 



10. Fasciculus unciformis. 



LESSON XCVII. 



The extensor of the brain, Avhich is called cortex, is gray, while the interior 

 is white. The average weight of the brain is forty-nine and one-half-ounces. 

 in the male, while it is a little lighter in the female. 



PLATE CLX. 



MUSCULAR BANDS — TAENIAfc COLI 



Transverse Skction of the Large Ixtkstine. 



The nervous system is developed from the neural tube. (Plates CLXIV- 

 CLXV-CLXVI-CLXV1 ! ). The substance of the brain and cord are made from 

 a thickening of the walls of the tube; the hollow of the tube makes the central 

 canal of the cord and the ventricles of the brain. The rooms, or ventricles in 

 the brain are filled with cerebro-S] Lnal fluid which acts as a cushion for the 

 brain and cord. There are five ventricles in the brain. The central canal in 

 the cord is dilated as it passes into the brain, between the cerebellum behind, 

 and the pons wi) medulla i x front; this dilatation is called the fourth ven- 





