AMPHIBIA. 37 



mylo-hyoideal, which is connected with and forms the most anterior part of the 

 constrictor muscle of the throat, and resembles the cutaneous in man ; it also sends a 

 branch to the membrane lining the mouth. In the snake, it gives branches to the 

 muscles of the jaws ; the greatest portion of it then passes within a canal in the lower 

 jaw ; it sends three branches through the opening at the inferior margin of this part, 

 two of them to communicate with the branches of the par vagum and ninth distributed 

 on the muscles and parts underneath the jaw, the other to give filaments to the 

 membrane of the mouth, as far as the sheath of the tongue : the trunk is continued 

 onwards through a foramen near the chin, to divide into branches, and terminate in 

 the lower lip. In the turtle, the sixth nerve arises from the oblong medulla in the 

 track of the pyramidal body ; it supplies the abductor and the muscles encircling the 

 optic nerve, and spreading over the convex portion of the sclerotic coat of the eye. 

 The hard portion of the seventh arises from the restiform body ; it crosses the external 

 auditory meatus, to give filaments to the digastric muscle inserted into the angle of 

 the lower jaw, and then passes to terminate on the constrictor muscle of the throat ; it 

 communicates with branches of the cervical nerves given to the lower portion of the 

 same muscle, which are composed of filaments derived from both the anterior and 

 posterior surfaces of the spinal cord. In the snake, it communicates with the ganglion 

 of the sympathetic, and then passes through the digastric muscle, to which it gives a 

 branch ; it communicates with the first spinal nerve, and terminates in the costa- 

 maxillary muscle. In the turtle, the auditory nerve arises from the restiform body ; 

 it divides into two principal branches ; the anterior passes to the termination of the 

 anterior and upright semicircular canals, the other is spread on the sack of the 

 labyrinth, after sending a branch to the termination of the posterior, upright, and the 

 horizontal semicircular canals. The glosso-pharyngeal arises from the restiform body ; 

 it passes underneath the sack of the labyrinth, gives filaments to muscles connected 

 with the lingual bone, and terminates on the membrane of the pharynx. In the snake 

 it passes to the superior cervical ganglion of the sympathetic ; it communicates with 

 the ninth after its combination with a branch of the par vagum, and terminates on the 

 glottis and the muscles attached to the anterior portion of the jaw for drawing forward 



