78 AVES. 



proceeds from the optic tract, which is connected with the thalamus, the pedicle of the 

 striated septum, and the optic lobe ; it is connected with its fellow in a commissure, 

 and from this the nerve proceeds to the eye to terminate in the retina. The third nerve 

 arises from the oblong medulla, it gives a branch to join a filament from the first trunk 

 of the fifth to form ciliary nerves, and then supplies the inferior oblique muscle, the 

 adductor, levator, and depressor. One half of the larger portion of the fifth arises from 

 the sensitive tract and the other half from the involuntary and forms a ganglion, the 

 smaller portion arises from the motive tract, superficially it is not very distinct from the 

 larger. The first trunk passes through the orbit and enters the nose close to the olfac- 

 tory nerve and appears connected with this, and gives filaments to the Schneiderian 

 membrane ; it meets its fellow on the floor of the nose, and then gives off a large 

 branch to the exterior of the upper jaw near the beak, and another to divide on the 

 palate and send branches through perforations in the bone to the membrane covering 

 the beak. The second trunk passes beneath the orbit to the posterior part of the beak 

 and palate, and divides into branches which supply the covering of those parts. A 

 part of the third trunk has a separate origin from that proceeding from the ganglion ; 

 it gives branches to the muscles of the jaws connected with the omoid and square 

 bones, and then enters a canal in the lower jaw, and sends filaments through perfora- 

 tions to the masseter and other muscles, and to the teeth and membranous covering of 

 the lower jaw, and particularly the beak ; a branch is given to the mylo-hyoideal 

 muscle, and one analogous to the maxillary portion of the digastric : in the goose it is 

 small, it is larger in the crane, and of great size in the pelican, for supplying the 

 extensive bag of the fauces. The sixth nerve arises from the oblong medulla in the 

 track of the pyramidal body, and is given to the abductor muscle of the eye and the 

 muscles of the nictitating membrane. The hard portion arises from the oblong 

 medulla in the track of the restiform body, it enters a foramen anteriorly to the 

 auditory nerve, it passes downwards and backwards on the outer side of the vestibule, 

 and escapes at a foramen in the posterior part of the external auditory meatus, after it 

 has communicated with the sympathetic nerve ; it then sends branches to muscles 

 analogous to the superior belly of the digastric and stylo-hyoideal, and communicates 



