508 THE BRAIN OF MAMMALS, BY TH. MEYNERT. 



enclosed in a gutter-like fashion by this principal root of the 

 glossopharyngeal nerve (Clarke). 



2. Median roots of the nervus vagus, which, proceeding 

 from fibrse rectse of the raphe', pass outwards into the vagus 

 between the hypoglossal roots that arise from thence and the 

 hypoglossal nuclei, in the form of fasciculi limiting the grey 

 floor anteriorly (fig. 257, x x). Other roots of the lateral 

 system probably possess the same mode of origin as the 

 vagus. 



3. The roots proceeding from the ganglia of the posterior 

 column of origin of the lateral system, including the origins 

 from the above-mentioned nuclei of the glossopharyngeal and 

 vago-accessory nuclei which spring from their nuclei inter- 

 nally to the common ascending root (figs. 257, 258 x 1 , XI 1 ). 



4. Root fasciculi proceeding from the fasciculus teres to the 

 vagus (Clarke). 



5. Root origins from the gelatinous substance (fig. 257, G) 

 within the ascending roots of the fifth, which attach them- 

 selves to the nervus vagus and glossopharyngeus as they 

 traverse the roots of the fifth (Clarke). 



6. Roots from the anterior columns of origin of the lateral 

 system which I have been able to follow continuously into the 

 glossopharyngeous and vagus (fig. 257, x 2 ) in almost every 

 transverse section. Running parallel to the principal root 

 towards the grey floor, and curving in front of it, like those 

 of the facial nerve, they form a genu to these two nerves, 

 that differs from the genu of the facial in the absence of any 

 vertical portion. 



These portions of the roots, both on account of the size and 

 form of the nerve corpuscles and on account of the lateral posi- 

 tion of their nucleus, which corresponds to that of the facial 

 and motor nucleus of the fifth, are to be regarded as motor 

 fasciculi of the lateral system. 



7. The inferior roots of the accessory nerve spring from the 

 lateral process of the anterior cornu of the spinal cord, as far 

 down as to the lowermost extremity of the decussation of the 

 pyramids, and, indeed, for the most part, not from the cells of 

 the planes of emergence, but by curving, from more distant 

 parts (Stilling, Lenhossek, Clarke, Deiters). The cells of origin 



