844 THE NERVES. 



difference in the form of the head. Consequently, in this comparative analysis we shall not 

 discover any fundamental differential characters. 



Ruminants. — There is no difference to note in the four fimt pairs. 



Trigeminal nerve. — Divided into three branches as in Solipeds. It has been stated that in 

 Ruminants the ophthalmic branches are distributed to the majority of tlie muscles of the eye; 

 in the Sheep, we have only seen the palpebro-nasal nerve offering this relationship to the 

 motor organs of that part. Tiie anterior palatine nerve is relatively voluminous. 



In the Ox and Sheep, the buccal nerve furnishes the excito-secretory nerve of the parotid 

 gland; it is inflected on the anterior border of tlie masseter, and follows Steno's duct, iu both 

 species, to reach the gland. It is often formed by two parallel filaments (Moussue). A filament 

 of the inferior branch of the buccal nerve which goes to the molar gland, is also excito-secretory 

 (Moussu). 



Facial nerve. — Towards the middle of its subparotideal course, tliis gives off a large 

 anterior auricular nerve ; when it arrives at the middle of the posterior border of the masseter 

 muscle, it divides into two branches. The inferior branch passes obliquely downwards and 

 forwards, towards the mental foramen, where it terminates as in the Horse; it furnishes an 

 anastomotic branch to the superior. The latter crosses the middle portion of the masseter, and 

 becomes mixed with the suborbital ramuscules of the fifth pair; about the midille of its 

 course it receives a filament from the superficial temporal nerve. We need not allude to the 

 auditory and glosso-pharyngeal nerves, except to say that the latter communicates with the 

 pneumogastric soon after its exit from the foramen lacerum. 



Pnenmogastric nerve. — This offers numerous differences in its roots and distribution. 



In the Ox and Sheep, the sensitive roots arise from an irregularly elliptical surface com- 

 prising the whole of the respiratory tract. They are from fifteen to twenty in number, and 

 often join each other; they may divide into three principal fasciculi arising at slight distances. 



The Tnotor roots are a little larger than in the Horse ; before joining the sensitive roots they 

 are confounded in a small ganglion that pertains to them. 



The jitgular ganglion is voluminous, but apart from this it presents the same features as in 

 the Horse, receiving all the proper roots of tlie pneumogastric and internal root of the spinal 

 accessory, and even those which are united in their own ganglion. The portion of the 

 ganglion that is more especially formed by the roots of tlie spinal accessory is rather an intri- 

 cation of nerve-fibres than a real ganglion ; it is impossible by the most minute dissection to 

 separate it from the rest of the ganglion. 



The jugular ganglion also receives a division of the glosso-pharyngeal, and it gives one to 

 this nerve and the external branch of the spinal accessory. 



The pneumogastric nerve, in the guttural -portion, is much larger than in the Horse. This 

 peculiarity is noticeable throughout its whole extent, and is indicated at its roots. 



The ganglionic plexus is absent in the Ox. The course and relations of the nerve in this 

 portion, are analogous to those observed in Solipeds. 



The pharyngeal nerve is voluminous, and the branch it sends to tlie oesophagus is the 

 largest of its divisions: this branch passes backwards to the surface of the constrictors of the 

 pharynx, joins the external laryngeal, gives a large branch to the thyro-pharyngeus, and is 

 insinuated on the sides of the oesophagus, between it and the thyroid gland ; there it divides 

 into two portions, one of which descends on the sides of the oesophagus, where it forms a very 

 rich plexus with the l)ranche8 from the inferior laryngeal, wliile the other is lost immediately 

 in the recurrent nerve at the thyroid gland. 



The external laryngeal arises at a short distance above the superior laryngeal, where it 

 receives a large branch from the glosso-pharyngeal and another from the sympathetic, and 

 immediately passes alongside the oesophageal branch of the pharyngeal nerve. With a little 

 attention, we may dissect a fasciculus coming from the external laryngeal and passing to the 

 crico-thyroid muscle, and the thyroid gland and its vessels, after receiving a branch from 

 the superior laryngeal. In the Sheep, the external laryngeal sometimes gives a branch to 

 the oesophagus, and whicli anastomoses with the inferior laryngeal, or descends on the side 

 of the tube, conjointly with the oesophageal branch of the pharyngeal. 



The superior laryngeal rises below the preceding ; it is very voluminous, and communicates 

 with the sympathetic, either directly or through the medium of the guttural plexus, and with 

 the pharyngeal nerves and external laryngeal. Beneath the thyroid cartilage, a large division 

 anastomoses with the inferior laryngeal, and is finally lost in that nerve below the larynx. It 

 is easily seen that this brancli gives, in the cervical region, a great number of filaments to the 

 oesophagus and trachea. 



With the exception of some insignificant peculiarities, the pneumogastric comports itself In 

 the cervical and thoracic regions as in the Horse. 



