PATHS OF THE CRANIAL NERVES 



555 



part in the optic chiasrn those coming from the internal portions 

 of the retina decussate, those from the external portions pass the 

 chiasm without crossing 

 and continue cerebralward 

 through the optic tracts, 

 which pass around the crurae 

 cerebri to enter the dien- 

 cephalon (Figs. 391 and 414). 



Some of these fibres ter- 

 minate at once in the lat- 

 eral geniculate body ; a few 

 are continued to the ante- 

 rior corpora quadrigemina 

 from which they are con- 

 nected by intermediate. neu- 

 rones with the lower groups 

 of motor ocular nuclei and 

 with the cervical region of 

 the spinal cord. Still other 

 fibres of the optic tracts, to- 

 gether with those neurones 

 of higher orders whose nerve 

 cells lie in the lateral gen- 

 iculate body, pass to the 

 pulvinar of the optic thala- 

 mus, and are probably con- 

 tinued thence by neurones 

 of a higher order through 

 the optic radiation to the 

 cortex of the occipital lobes. 



The Olfactory Nerve. 



The peripheral neurones of Fo, olfactory fibres \ Glo, olfactory glomeruli; 

 the first Or olf actor V nerve Lo - olfactory lobe; 3f, molecular layer of the 



J _1i? _A. 1 1 1_ . irrw -j 1 _11,. . TiT^ 



-Vh 



FIG. 415. OLFACTORY LOBE AND BULB OF A 



RABBIT ; HORIZONTAL SECTION. 

 Bo, olfactory bulb ; Ca, anterior commissure ; 



include those nerve cells, 



olfactory bulb ; MZ, mitral cells ; Nc, caudate 

 nucleus ; SaS, white mutter of the septum ; Sp, 

 the Olfactory cells, which are septum pellucidum ; Str'gr, granular layer ; Tr.o, 

 found in the Olfactory mil- lateral olfactory tract ; VB, ventricle of the bulb; 



Vh, anterior horn of the lateral ventricle. W ei- 



cous membrane,* whose ger t's stain. (After Kolliker.) 

 distal processes or dendrites 



reach the free surface of the mucosa, and whose central processes, 

 the neuraxes, pass, as non-medullated nerve fibres of the olfactory 



* See Chapter XIV. 



