252 Mammalia, 



terminates in tlie Pharynx, and(2) a Superior Laryngealhranch, 

 rather larger than the preceding ; which comes off about one 

 inch from the skull, inclines slightly forwards internal to the 

 carotid artery, and passes to the side of the Larynx, which it 

 enters near the margin of the thyroid cartilage. 



The Qlosso- Pharyngeal, the third Cranial nerve that comes 

 through the foramen lacerum, is the smallest of the three, and 

 a mixed motor and sensory nerve, but pierces the dura mater 

 through a distinct opening : presenting in the aperture of 

 exit- two small ganglionic swellings, from the larger of which 

 spring the branches that unite this with the other nerves in 

 this part. Leaving the cranium, it passes internal to, and in 

 the same direction with the stylohyal bone to join the back 

 and side of the tongue. In its course it gives off, close to 

 the ganglion, a nerve to the tympanum called Jacobson's 

 nerve, and at about one and a-half inch lower down a branch 

 to the tonsils ; in the neighbourhood of this last it anasto- 

 moses freely with fine branches from the Yagus forming a 

 plexus. 



The Anterior Termination of the Sympathetic System. 

 In the dissection of the Rat the Student will have traced 

 the main cords of the sympathetic system up to the head : he 

 has now before him the superior cervical ganglion, the largest 

 of the three ganglia in the neck. From this ganglion nerve- 

 twigs communicate with the ganglia on the Pneumogastric and 

 Glossopharyngeal nerves. The apparent continuation from 

 the upper part of the ganglion enters the skull by penetrating 

 the back part of the cavernous sinus, where it forms the 

 Cavernous Plexus. A branch from this plexus joins the larger 

 (or superior) Superficial Petrosal nerve (the first branch of 

 the Facial nerve), and the two conjoined are termed the 

 Yidian nerve, which, as above said, is in connection with the 

 Sphenopalatine Ganglion. 



