16 



MORPHOLOGY OF THE 



section, too, fibres can be seen coming from the Y ganglion 

 and completely filling the Randschleier ; bnt there are 

 others, which enter the medullary wall, and running down- 

 ......... ward lielp to form tlie 



/ - /' V tractns solitarins. 



Tt will l)e observed 

 that these fibres are 

 absolutely wanting in 

 Figure 7. Tliis simply 

 means that they are 

 developed at a later 

 date ; for they are cer- 

 tainly ver}^ distinct in 

 Figure 12, which is an 

 older embryo. Others 

 join fibres derived from 

 the (VII and VIII) gan- 

 glia, which likewise de- 

 scend in the medullary 

 wall, external to the 

 tractus solitarins and 

 close to the Randschleier. 

 These fibres probably 

 correspond to the so- 

 called ascending trigem- 

 inal tract. It will also 

 be noticed that the 

 bundle forming the trac- 

 tus solitarins is larger 

 in size than in the 

 course due to the increase of 



Fig. 12. 



Soction of the nu'dulla of an embryo ra])bit 

 i:>.(> mill, parallel to the floor of the fourth ven- 

 tricle. F, ganglion. IT/, VII ganglia. X, 

 se(;tions of the IX and X ganglia. J, jugular 

 vein. OT, otic vesicle. TS, tractus solitarins. 



younger embryo. This is of 



