356 H. W. NORMS AND SALLY P. HUGHES 



THE GLOSSOPHARYNGEAL NERVE 

 1 . The roots and ganglia in the glossopharyngeal nerve 



The ganglion of the ninth nerve is farther removed from the 

 brain wall than that of any other cranial nerve. It is situated 

 in the ventrolateral part of the ear capsule, near the posterior 

 end of the latter, in a large chamber hollowed out of the cartilage. 

 Its root, composed of lateral-line, visceral sensory, and visceral 

 motor fibers, passes- anteriorly and mesially from the ganglion 

 to its entrance into the medulla at a point about opposite the 

 middle portion of the spiracle. At the anteromesial end of the 

 visceral sensory ganglion and extending mesially upon the root, 

 is a small mass of cells, the ganglion of the lateral-line compo- 

 nent (figs. 24 and 48, gspt. IX). The visceral sensory root 

 enters the medulla and passes anteromesially into the visceral 

 lobe. The lateral-line component enters the brain immediately 

 dorsal to the anterior part of the visceral root, ventral to the 

 extreme anterior end of the lateral-line root of the vagus nerve 

 (fig. 24). Within the brain the lateral-line root of the ninth 

 nerve runs anteriorly ventral to the mesial border of, and nearly 

 parallel with, the root fibers of the lateralis X, but always dis- 

 tinct from them. Anteriorly, the lateral-line element of the 

 ninth approaches that of the tenth, and finally takes a position 

 at the mesial border of the other lateral-line tracts, just lateral 

 to the visceral lobe. The motor elements in the glossopharyn- 

 geal root occur in scattered bundles. In similar fashion they 

 connect with the brain by a number of minute rootlets, in position 

 anterior to the other roots. 



2. The lateral-line elements in the glossopharyngeal nerve 



Various writers have recognized lateral-line elements in the 

 ninth nerve of fishes, although their presence there has been gen- 

 erally overlooked or ignored. Allis ('89, '97) describes and figures 

 a lateral-line component of the glossopharyngeus of Amia, inner- 

 vating one canal organ and a line of pit-organs. Ewart ('92) 

 and Ewart and Cole ('95) found a lateral-line component in the 



