742 THE NERVES. 



solar plexus and superior esophageal nerve, a ricli plexus, from -whicli arise branches to 

 the liver, abomasu-m, and duodenum. 



The superior cBsophageal nerve is chiefly distributed to the rumen. Before reaching 

 tlie stomach, it gives several divisions to the plexus already mentioned — and which 

 might be named the " hepatic plexus," receives a large branch from the solar plexus, 

 and sends to it a smaller one. It afterwards divides into two principal branches, the 

 largest of which passes along the superior fissure of the rumen, along with the vessels of 

 that organ. According to Lavorat, tliis branch forms a large plexus there, whicli has in 

 its centre a ganglionic enlargement, whence emanate the ramusoules that go to the whole 

 of the upper face, sides, and lower surface of the rum'jn. In the Sheep we have not found 

 a ganglion, but this does not prevent this branch from being distributed to all the parts 

 indicated by Lavocat. 



The other branch is very large, and situated in the omentum until it arrives at its 

 convex border, when it leaves it to be distributed to the left side of the abomasum ; 

 while the analogous nerve from the inferior oesophageal passes more especially to the 

 right face. 



Spinal accessory. — The origin of this nerve oflers slight differences, which we have 

 indicated in speaking of the motor roots of the pneumogastric. With regard to its dis- 

 tribution in the Ox, it offers the following features : At the inferior extremity of the 

 transverse process of the atlas it divides into two branches, a superior and inferior. The 

 first is a liltle larger than the spinal accessory of the Horse, and comports itself as in 

 that animal. The inferior branch is directed downward and backward, traverses the 

 mnscle we have named the sterno-suboocipital, beneath a tendon that runs across the 

 muscular fibres, and arrives between that muscle and the sterno-niaxillaris. At this 

 p lint it separates into a certain number of ramuscules, the first three or four of which 

 are slightly recurrent, and enter the upper jiart, of the sterno-maxillaris ; the others are 

 large and directed towards tlie sternum, to be dislributed to the latter muscle, or to it and 

 the sterno-suboccipitalis. 



These branches of the spinal accessory represent the branch which, in the Horse, passes 

 exclusively to the sterno-maxillaris. In reflecting on the distribution they offer in the 

 (Ix, we are brought to the conclusion that the i-ternal band, which has been described as 

 belonging to the first, forms, with the sterno-suboccipitalis, one and the same muscle — 

 the analogue of the sterno-maxillaris or steino-mastoideus of Solipeds. These two 

 muscular fasciculi are, otherwise, closely attaclied to each other, if not confounded near 

 their origin at the anterior prolongation of the sternum. 



Lastly, the great hypoglossal nerve, before crossing the pneumogastric, communic.ites 

 with the first cervical by a considerable branch ; lower, it gives oif a long ramuscule 

 tl at descends on the carotid artery. 



Pig. — We need not refer to the olfactory, optic, or motor nerve of the er/e, neither to 

 the glosso-pharyngeal, as what has been said about them in Solipeds holds good in this 

 .animal. 



Trigeminal nerve. — This also divides into three principal branches. The palpebro- 

 nasal ramuscule of the ophthalmic branch anastomoses with a motor nerve of the eye oh 

 the deep face of the external rectus muscle. The superior maxillary nerve leaves the 



■ Cranium by the great sphenoidal slit, and immediately enters the superior dental foramen ; 

 , its orbital course is therefore very short. 



Its spheno-palatine branch passes at once below the alveolar tuberosity, where it 



■ divides into several ramuscules : one, entering the palatine fissure, forms the posterior 

 palatine nerve ; the others pass into the palatine arch at various distances, to constitute 

 the middle palatine nerves ; some of them even enter the palatine canal with the anterior 

 palatine or palato-labial nerve. 



Facia!.— Beneath the parotid gland, this divides into several branches, of which there 

 are three principal. One is directed upwards, and passes in front of the ear ; this is the 

 smallest. The second proceeds forward, crosses the masseter near the zygomatic process, 

 unites with the inferior branch, and is expended among the suborbital ramuscules of the 

 superior maxillary. The third passes downward and forward, under the parotid gland, 

 . arrives in the intermaxillary space, is inflected in front of the masseter to become super- 

 ficial, and terminates with the middle branch. Towards the niaxillo-labialis muscle, 

 this inferior branch gives off' a ramuscule to the lower lip. 



FneHmngastric—This joins the great sympathetic near the upper third of the neck, 

 and at its point of union offers a greyish enlargement resembling the gangliform plexus 

 of Mm. Until the origin of the oesophageal nerves, the pneumogastric of the Pig 

 resembles that of the Horse. The latter is voluminous, and does not divide into two 

 •branelies -immediiitely beyond the bronchial plexus, but at some distance from it. 

 Numerous anastomnscs exist between the two oesophageal nerves —superior and inferior, 



