14 



MORPHOLOGY OF THE 



Figure 7 



The}' are situated within the medullary wall, 

 opposite the otic vesicle, and are continuous with the tractus 



Fig. 10. 



Section of the medulla of an eniliryo 

 rabbit lO.s mm. at right angles to the floor 

 of the medulla, in the region of the IX 

 ganglia. TS. tractus solitarius. OT. otic 

 vesicle. GE, Elirenritter's ganglion. GP. 

 ganglion petrosum. aorta. •/. jugular 

 vein. C. carotid. 



solitarius. 



In figure 10 we have a 

 transverse section of the 

 medulla at the level of 

 the IX nerve. 



This drawimi: shows 

 the pharynx, aorta, in- 

 ternal carotid, and jugular 

 vein in cross-section, as 

 well as portions of the 

 otic vesicle; but the sal- 

 ient point for us is the re- 

 lation of the IX ganglion. 

 This is plainly seen, with 

 its two divisions, Eliren- 

 ritter's ganglion and the 

 ganglion petrosum. 



Two sets of nerve 

 fibres are in relation with 

 the medullary wall. The 

 inner is probably the lat- 

 eral root of the IX nerve, 

 rising from the ventral 

 zone of the medulla. 



The external is the 

 posterior root, entering 



the medullary wall pre- 

 vious to its division to aid in the formation of the tractus 

 solitarius. 



