PISCES. 33 



filaments to terminate about the under lip. The auditory portion of the fifth passes 

 to the ear, and gives branches to the sacks containing the cretaceous matter and the 

 globular enlargements of the semicircular canals, whilst a nerve, similar to the glosso- 

 pharyngeal, communicates with it on the large sack, and gives filaments to the 

 termination of a semicircular canal, and then passes outwards to give filaments on the 

 surface of the first and the corresponding one of the second division of the gills, and 

 terminates on the membrane of the mouth. The par vagum is seen passing to the 

 gills, giving filaments to the muscular appendages of these, and then sending a large 

 branch to distribute filaments to every part of the opposite surface of each division, 

 except the first ; it sends a branch anteriorly to the stomach, which communicates 

 with the sympathetic; it sends a large branch posteriorly to pass underneath the 

 muscles of the back, and give filaments to these in its course ; this branch lies upon 

 and crosses the spinal nerves ; near .the tail it emerges from underneath the muscles, 

 and passes just under the skin to the extremity of this part ; it has been carefully 

 examined, but communications between it and the spinal nerves have not been 

 satisfactorily observed. 



The spinal cord is seen gradually decreasing as it extends towards the tail. 

 Each posterior bundle of the spinal nerves terminates in a ganglion, and is joined 

 by a corresponding anterior bundle ; it is then continued outwardly, and becomes 

 connected with several others from the upper part of the spinal cord, to form 

 a large mass of nerve somewhat like the axillary plexus. Lower down other 

 junctions take place, but these are smaller, being composed of fewer nerves. The 

 nerves thus formed pass forward, and then divide into branches for the anterior 

 and posterior surfaces of the body. The posterior divisions send off small branches 

 which pass between the long cartilaginous ribs or processes, and supply the 

 muscles and skin. The anterior division passes forward in a similar manner, 

 and, after sending up branches to the muscles of the chest, and others to those 

 of the abdomen, is continued forward over the anterior surface of the body, and 

 divides into branches to be distributed in a similar manner to those on the 

 posterior part. 



F 



