PISCES. 17 



glosso-pliaryngeal nerve arises from the restiform body; it is distinct ; it sends a portion 

 to communicate with the auditory nerve on the large sack of the labyrinth, and the 

 termination of one of the semicircular canals ; the rest of the nerve passes to terminate 

 on the first division of the gills and the membrane of the mouth. In the cod the par 

 vagum arises from the restiform body, gives branches to the gills and muscles con- 

 nected with them, sends two branches downwards and outwards underneath the skin of 

 the side, and a larger one, which is the continuation, to terminate on the stomach. In 

 the skate it is similar ; the nerve given to the surface of the body first passes under- 

 neath the muscles of the back in contact with the spinal nerves ; it then emerges from 

 these near the tail, and is continued to the end of this covered only by the skin. 



SPINAL CORD AND NERVES. In the cod, the spinal cord is continued 

 from the oblong medulla, gradually decreasing to the tail, where it terminates in a 

 bulb : it gives off anterior and posterior bundles of nerves. Each anterior and 

 posterior bundle is divided into two parts ; one from the anterior is joined by one 

 from the posterior, and passes forward to the muscles and skin on the anterior part 

 of the spine : the other branch of the anterior, after it has communicated with the 

 posterior branch passing forward, goes backwards, and is joined by the second branch 

 of the next posterior bundle, to terminate on the muscles and skin at the posterior 

 part of the spine. Neither of the branches of the posterior bundle forms a ganglion. 

 The same disposition is continued to within a short distance of the tail, where the 

 whole of each anterior and posterior bundle becomes joined, and the division into 

 branches for the anterior and posterior parts of the spine takes place. In the skate 

 the spinal cord is similar ; but a ganglion at the extremity was not observed, and the 

 disposition of the spinal nerves is more simple than in the cod at their origins, and 

 each of the posterior forms a small ganglion : the arrangements of the spinal nerves 

 are afterwards different, in respect of the absence of small fins, and in the formation of 

 some larger trunks corresponding with the axillary plexus. 



SYMPATHETIC NERVE. In the cod, the sympathetic nerve arises from a 

 branch of the fifth, the glosso-pharyngeal, and par vagum : a branch from the left side 

 passes across to the right side, to form a ganglion from which proceeds the splanchnic 



D 



