NERVOUS SYSTEM OF VERTEBRATA. 

 Fig. 23. 



129 



Course of the Motor tract after Sir C. Bell. A, A, fibres of the hemispheres, converging to form the ante- 

 rior portion of the cms cerebri; B, the same tract where passing the eras cerebri; c, the right pyramidal 

 body, a little above the point of decussation; D, the remaining part of thepons varolii. a portion having been 

 dissected off to expose B. 1, olfactory nerve, in outline ; 2, union of optic nerves; 3, 3, motor oculi ; 4, 4, 

 patheticus ; 5, 5, trigeminus ; 6, 6, its muscular division ; 7, 7, its sensory root ; 8, origin of sensory root from 

 the posterior part of the medulla oblongata ; 9, abducens oculi; 10, auditory nerve; 11, facial nerve; 12, 

 eighth pair; 13, hypoglossal ; 14, spinal nerves; 1.5, spinal accessory of right side, separated from par vagum 

 and glosso-pharyngeal. 



continuation. Also forming part of the posterior division of the crus cerebri, 

 and separated from the anterior by the transverse septum, is a layer of fibres 

 which ascends from the Olivary bodies, some of which terminate in the Cor- 

 pora Quadrigemina. 



