MEDULLA on LONG ATA OF THE RAH BIT. 



15 



The two Q^anglia are connected by nerve fibres, and 

 others are seen extending downward, internal to the 

 jngular vein. 



Figure 11 is a trans- 

 verse section of the X 

 ganglion, and at a super- 

 ficial glance does not differ 

 materially from that of the 

 IX. 



Its two ganglia, the 

 jugular and nodosum, are 

 quite characteristic and 

 larger in size than those 

 of the IX. The posterior 

 nerve root from the ^an- 

 glion jugidare enters the 

 medullary wall before its 

 division to join in the for- 

 mation of the tract us soli- 

 tar ins, and the lateral root 

 is also present, as in the 

 former section. 



If we now compare 

 Figure 7 with a similar 

 section of an older em- 

 bryo, one which measures 

 13.G mm. in length, as is 

 shown in Figure 12, we 

 shall find several differ, 

 ences; but most of them 

 relate to the degree of development of nerve fibres. In this 



'iiihryo 



Fig II. 



Section of the medulla of an 

 rabbit 10.8 mm. at right . angles to the floor 

 of tlie medulla, in the region of the X 

 ganglia. tractus solitarius. GJ^ gan- 



glion jugulare. GN, ganglion nodosum. 

 X//, hypoglossal nerve. A^ aorta. 

 jugular vein. C, carotid. 



