42 AMPHIBIA. 



the par vagum, to the first thoracic ganglion ; it sends up branches to communicate 

 with the cervical nerves : those at the upper part of the neck are delicate, and not 

 easily traced : they do not enter a canal with a vertebral artery, as in mammalia and 

 birds, but pass on the outside of the spine ; it communicates with the nerves about to 

 form the axillary plexus, also with the trunk of the par vagum, and sends many 

 filaments on the arteries. The prolongation from it through the thorax communicates 

 or coalesces with the ganglia of the dorsal nerves, but the anterior branch of each 

 intercostal artery passes through or is embraced by this union. The prolongation 

 frequently consists of a thick branch, and a very fine one, and passes down to each 

 succeeding ganglion ; but neither of them passes behind the neck of each rib, as in 

 birds. It gives many small branches to the connecting membrane of the viscera, but 

 the principal branches of each side form two intricate plexuses, which are in the place 

 of semilunar ganglia; the superior or smaller portion follows the branches of the 

 coaliac artery to the stomach, the lower or larger, the branches of the mesenteric artery 

 to the intestines. Other branches pass from the sympathetic to the kidney, and the 

 spinal nerves keep sending filaments towards this part, which seems to be the 

 situation of the prolongation ; and it is continued down to the side of the rectum, 

 communicating with all the spinal nerves, until their extreme minuteness prevents 

 their further continuation from being easily followed. In the snake, the sympathetic 

 has a superior cervical ganglion situated near to, and connected with, the trunk of the 

 par vagum. It communicates with the hard portion and sends upwards a branch 

 some way in a canal at the base of the cranium, which forms a small ganglion with a 

 branch of the second trunk of the fifth, and sends filaments to the membrane covering 

 the posterior part of the mouth and palate : one of these communicates again with 

 the second trunk of the fifth before its termination ; this ganglion then sends another 

 branch forward to form another ganglionic union with a branch of the second trunk 

 of the fifth, and from this a branch is sent to the posterior part of the nose to ramify 

 on the Schneiderian membrane : other branches are given to the membrane covering 

 the mouth and palate ; one passes forward, and communicates again with a branch 

 of the second trunk of the fifth, and is distributed on the membrane covering the 



