MEDULLA OBLONGATA. 



679 



Spinal Cord, by a band of "arciform" fibres, whose connections were first dis- 

 tinctly described by Mr. Solly; 1 of these there is a superficial set which unites 

 itself with the pyramidal columns, and a deep set which comes into relation 

 with the olivary. Their gray nucleus, or "restiform ganglion," appears to be 

 the ganglionic centre of the Pneumogastric nerves, and of a portion of the roots 

 of the Glosso-pharyngeal. iv. The Posterior Pyramids are scarcely distin- 



Fig. 180. 



' 



Course of the Motor tract, according to Sir C. Bell. A, A, fibres of the Hemispheres, converging to form 

 the anterior portion of the crus cerebri ; B, the same tract, where passing the crus cerebri ; c, the right Pyra- 

 midal body, a little above the point of decussation ; D, the remaining part of the Pons Varolii, a portion hav- 

 ing 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 ; 15, spinal accessory of right side, separated 

 from par vagum and glosso-pharyngeal. 



'Philosophical Transactions," 1836. 



