124 ANATOMY OF VERTEBRATES. 



the third division of the fifth is traced on the left side of fig. 49, 7, 

 passing beneath the ganglion. There is no ' otic ' ganglion in 

 Birds. 



The facial nerve, or portio dura, arises immediately anterior to 

 the acoustic from the prepyramidal tracts, enters the petrosal an- 

 terior to the acoustic, quits it to pass into the fallopian canal, 

 sends off the ' chorda tympani ' to the ramus alveolaris inferior of 

 the trigeminal, and communicates with the sympathetic ; it passes 

 out behind the tympanic bone (as in Mammals), gives branches 

 to the digastric and stylohyoid muscles, and combines with the 

 glossopharyngeal, vagus, hypoglossal, and upper cervical nerves, 

 to form the plexus supplying the anterior part of the constrictor 

 colli muscle. 



The auditory nerve, or portio mollis, is large, soft, and of a 

 reddish colour; it is received into a depression on the petrosal, 

 fig. dQ, 7, whence it penetrates by several small foramina to the 

 labyrinth. 



The roots of the ^ eighth ' nerve penetrate the exoccipital by 

 two or three foramina, and unite on their emergence to form the 

 ganglion, from which the glossopharyngeal and the pneumo- 

 gastric trunks diverge. The glossopharyngeal is large ; it com- 

 municates more freely with the sympathetic than does the 

 pneumogastric in the neck ; it sends off a small internal branch in 

 front of the muscles of the neck ; a small posterior twig which 

 unites with the pneumogastric, and a large inferior branch to the 

 anterior part of the neck. The latter is a continuation of the 

 nerve itself; it descends along the oesophagus and divides into 

 two principal branches, of which one passes to the cerato-max- 

 illary muscles, and this branch is remarkably tortuous in the 

 Woodj)ecker, in order to be accommodated to the extensile motions 

 of the tongue ; it supplies the upper larynx, and the surfixce of 

 the tongue, as far as the ti}^. The other branch descends along 

 the lateral parietes of the oesophagus, and sends off a twig to join 

 the lingual nerve. The termination of the glossopharyngeal is 

 expended upon the oesophagus. 



Tlie pneumogastric, after communicating with the glossopha- 

 ryngeal, sympathetic and ninth nerves, passes down the neck, 

 along with the jugular vein, and closely connected with the spinal 

 nerves. The right trunk crosses the arch of the aorta, and sends 

 off the recurrent round that vessel, the left trunk reflects its 

 recurrent near the origin of the bronchi ; the recurrents supply 

 the lower larynx and part of the trachea, but are chiefly spent 

 u]>on the oesophagus. The trunks of the two pneumogastrics 



