THE CRANIAL OR ENCEPHALIC NERVES. 743 



At their termination they differ much from each other in volume ; the inferior is very 

 small, and terminates on the anterior face of the stomach ; the superior, much larger, 

 partly remains at the stomach, and partly crosses the small curvature of that viscus to 

 enter the solar plexus. 



Spinal accessory. This nerve commences and terminates as in Solipeds. After being 

 inflected backward on the anterior border of the mastoido-humeralis, it divides into two 

 ramuscules a deep and superficial. The first is confounded with a cervical nerve, near 

 the intervertebral foramen through which the laiter passes; the second goes to the 

 trapezius muscle, in which it is expended. 



Near the base of the tongue, the hypoglossal gives off a filament that passes to the 

 genio-hyoideus muscle. 



CARNIVOBA. In these animals, the majority of the cranial nerves do not offer any 

 important differences. We will, therefore, say nothing concerning the first two pairs, 

 the motores oculorum, spinal accessory, and glosso-pharyngeal, except that the motor 

 nerves of the eye are mixed with the filament of the ophthalmic branch among the 

 muscles of the orbit. 



Trigeminal nerve. When the branch constituting the superficial temporal nerve 

 reaches the posterior border of the maxilla, it divides into several ramuscules; one 

 portion lies beside the middle branch of the facial, the other accompanies the anterior 

 auricular nerve by becoming intimately united to it. We have also found, in the Dog, a 

 branch that is detached from the inferior maxillary, almost immediately after its exit 

 from the cranium ; it descends into the intermaxillary space, in company with the facial 

 artery ; at the posterior border of the mylo-hyoideus muscle it separates into two 

 ramuscules : one is applied to that muscle, and follows it to near the symphysis of the 

 jaw ; the other is inflected outwards and upwards, in front of the masseter muscle, and 

 joins the inferior branch of the facial. Owing to this arrangement, each of the branches 

 of the facial is provided with a sensitive ramuscule from the fifth pair. 



Facial. At its exit from the external auditory hiatus, it divides into four branches, 

 three of which appear to form its termination. The first, the smallest, is directed down- 

 wards across the parotid gland, and constitutes the cervical ramuscule. The other three 

 are distinguished as superior, middle, and inferior. 



The superior branch, the largest, ascends towards the forehead, and describes a curve 

 whose convexity is upwards, turns round the orbit, and terminates near its nasal angle. 

 In its course it furnishes : 1, An anterior auricular ramuscule ; 2, Above the insertion of 

 the masseter, several muscular filaments ; 3, It is crossed, above the eye, by the super- 

 ciliary filaments of the ophthalmic nerve. The middle branch accompanies Stenon's duct 

 to the surface of the cheek ; reaching the anterior border of the masseter, it anastomoses in 

 a very flexuous manner with the ramuscule of the inferior branch, and terminates in the 

 upper lip and the end of the nose. The inferior branch passes towards the maxillary 

 fissure ; there it receives the sensitive ramuscule sent to it by the fifth pair, gives off 

 filaments to the middle branch, and is then continued into the lower lip. 



Pneumogastric. The sensitive roots closely resemble, in their disposition, those in the 

 Ox. The motor roots are separated into two series of filaments ; the anterior unite in a 

 small ganglion, then pass into the jugular ganglion ; the posterior lie beside the medul- 

 lary root of the spinal accessory, but leave it to become united with the jugular ganglion. 



Below the foramen lacerum, the pneumogastric nerve gives off the pharyngeal nerve 

 before forming the analogue of the plexiform ganglion of Man. This plexus is better 

 defined than in him, and is a real fusiform elongated ganglion, at the grey basis of which 

 some white filaments are seen. It is situated a little farther from the cranium than the 

 superior cervical ganglion. The ganglion itself furnishes the superior laryngeal nerve, 

 which gives off, as in Man, the external laryngeal nerve. 



There is nothing to indicate in the pharyngeal nerve, its disposition being absolutely 

 the same as in the Ox. 



In the Dog the superior laryngeal has a curious disposition, which has not yet. to 

 our knowledge, been described. Reaching the inner face of the thyroid cartilage, it gives 

 off, as in the other animals, filaments to the glottis, epiglottis, base of the tongue, and 

 oesophagus ; but the ramuscule of Galien, which nearly equals the superior laryngeal in 

 volume, does not anastomose with the inferior laryngeal ; it gives a large branch to the 

 crico-arytenoid muscle in passing to its surface, and then leaves the larynx to the inside 

 of the recurrent, descending on the trachea as far as the entrance to the chest. In that 

 cavity, the descending branch of the superior laryngeal forms two divisions that com- 

 municate with the ramuscules of various other nerves passing into this region. On the 

 j right side, the largest division receives a voluminous branch from the inferior cervical 

 ganglion; then the two divisions unite, and join the pneumogastric after it has turned 

 round the brachial trunk, a little behind the point of emergence of the mfeiior lar \ngenl. 



