388 DISSECTION OF THE RABBIT. 



Sylvian fissure, separating the frontal lobe from 

 the temporal. 



b. The olfactory lobes lie, in their hinder portions, 



along the under surface of the frontal lobes of 

 the hemispheres, extending back as far as the 

 Sylvian fissures. In front, they project some 

 distance beyond the hemispheres. 



c. The infundibulum is a median rounded elevation 



lying between the temporal lobes, about the 

 middle of the length of the brain : at its apex 

 is the rounded vascular pituitary body. This 

 latter- is usually left behind in the pituitary fossa 

 in the base of the skull when the brain is re- 

 moved, and a slit-like aperture is then left at 

 the apex of the infundibulum, leading into the 

 third ventricle. 



d. The optic chiasma is a transverse band of nerve- 



fibres lying immediately in front of the infundi- 

 bulum. From its anterior border the optic 

 nerves arise, and from its outer ends the optic 

 tracts may be followed backwards towards the 

 optic lobes by gently pressing the temporal lobes 

 aside. 



e. The corpus mammillare, or corpus albicans, is a 



small rounded median elevation immediately 

 behind the infundibulum. 



f. The pons Varolii is a stout band of transverse 



nerve-fibres which crosses the ventral surface 

 of the medulla opposite the posterior ends of the 

 hemispheres. It connects the two sides of the 

 cerebellum with each other. 



g. The crura cerebri are two large bands of nerve- 



fibres, immediately in front of the pons Varolii, 

 which run forwards, diverging from each other, 

 and connect the medulla oblongata with the 

 hemispheres. 



