688 DISSECTION OF THE EAR. 



belongs to the ampullary swelling (b) on the tube in the posterior vertical 

 semicircular canal. 



On the sacs the nerve divides, and its filaments separate, some fibrils 

 passing through the otolith and others outside it, and pierce the middle 

 layer of the wall. Now becoming axis cylinders they divide, and unite 



Fig. 249. 



DISTRIBUTION OF NERVES TO THE MKMBRANOUS LABYRINTH (Breschet). 



a. Nerve to the saccule. c - Branch of nerve entering the large sac or 



&. Nerve entering the ampullary enlargement utricle, 



on a semicircular tube. 



in a plexus beneath the epithelium, and are thought to be united with the 

 deep ends of the spindle-shaped cells with hair-like processes. 



On the ampullary enlargement of the semicircular tubes the nerve 

 enters the external side, where it forms a forked eminence (Steifensand), 

 corresponding with the projection in the interior. The nerve divides at 

 first into two chief pieces, which are directed to the sides; and it is doubtful 

 whether filaments extend into the tube beyond those eminences. Finally 

 it pierces the wall of the tube, and forming a sub-epithelial plexus of 

 nerve-fibres, as in the utricle, is supposed to be connected with similar 

 auditorial cells. 



