FEOG 249 



Do the cavities communicate with the duct? What 

 is the shape of the third ventricle? JSTote the 

 lateral ventricles, one in each of the cerebral 

 lobes. What is their shape ? Do they extend for- 

 ward into the olfactory lobes ? Look for an open- 

 ing, the foramen of Monro, leading from the 

 third into each of the lateral ventricles. What is 

 its position ? 

 Make a diagram showing the cavities of the brain. 



Make an incision separating the olfactory nerves 

 from the lobes ; gently lift up the anterior end of 

 the brain, and bend the latter backward until it 

 rests upon the spinal cord. In doing so cut each 

 of the nerves passing out through the cranial 

 walls. The ventral surface of the brain wiU then 

 be exposed. JSTote the pia mater with its blood- 

 vessels. Eemove the pia. Can you trace the 

 ventral roots of the olfactory nerves run- 

 ning back upon the olfactory and cerebral lobes ? 

 Are the cerebral lobes entirely separated at any 

 point on their ventral surface ? Between the bases 

 of the latter lobes find a rounded surface, the 

 lamina terminalis. Extending around the pos- 

 terior portion of the lamina find the roots of the 

 optic nerves, connected in the middle line by the 

 optic chiasma. Eunning dorsally from the chi- 

 asmaon each side is an optic tract. What is the 

 appearance of the optic lobes as seen from below ? 

 What is their position with regard to the optic 

 nerves, chiasma, and tracts ? Immediately behind 

 the chiasma find a lobed body, the tuber cine- 

 reum. What is its shape ? What is its relation 

 to the thalamencephalon ? Directly back of the 

 tuber find the stalk, the infondibulum, of the 



