THE NERVOUS SYSTEM 



1483 



with the arborizations formed by the dendrites of the mitral cells, 

 situated in the granular layer of the bulb (see p. 1448). 



The olfactory nerve is the ner\^e of smell. 



Second or Optic Nerve.— This nerve arises from the brain by 

 means of the optic tract, the deep connections of which have been 

 already described (p. 1424). Each optic tract passes forwards and 

 inwards to the optic commissure or chiasma, which is situated in 



Olfactory Bulb 



Fissure of Sylvius 



Broca's Area 



Li-cns Perforatus 

 Anticus 



.. Tuber Cinereiun 



Cocpns Albicans 

 Crus Cerebri 



Locus Perfotatu 

 Posticus 



Pons Varolii 



Fifth Nerve 

 Sixth Nerve 

 Facial Nerve -^ 

 Pars Intermedia 

 Auditory Nerve-'' 

 bsso-pharyngeol Ner%-e - 

 Pneumogastric Nerve 

 Spinal Accessory Xene' 



Hypoglossal Nerve 



Medulla Oblongata 



Spinal Cord 



Fig. 61 S. — The Base of the Encephalox, and the Cranial Nerves. 

 I . Frontal Lobe (Orbital Surface) ; 2, Temporal Lobe ; 3. Cerebellum. 



front of the interpeduncular space. The optic nerve of each 

 side arises from the anterior part of the optic commissure. 

 It courses forwards and outwards to the optic foramen, through 

 which it passes into the orbit, piercing the dura mater, and re- 

 ceiving a sheath from it, as well as from the arachnoid membrane. 

 Having reached the back part of the eyeball, it pierces the sclerotic 

 and choroid coats ^ inch to the nasal or inner side X)i the axis 



