61 



.9. Summary of the Oblongata. 



The strnctaril features of tha oblont^itd of Wustslus may 

 be horaologizei with those of the spinal ooni to an unusual 

 legree of cleanass. 



The ventral cornu is representei by the nucleus of the 

 VT nerve, and by the scatterei commissural and tract-neurones 

 of the formatio reticularis. 



The lobas vagi is, morphologically, the centre of the 

 viscero-sensory system, but there has been annexed to it a 

 complex of peripheral sense-organs. It has come to be, there- 

 fore, the centre for the entire communis system, components 

 of the VII, IX, and X nerves. Sndings are found related to 

 neurones of the Golgi TI type. These send tneir axones toward 

 the viscero-motor nucleus. Fewer fibres of the system enter 

 the fasciculus communis than in either the teleosts or the 

 amphibians. 



The viscero-motor nucleus is the representative of the 

 paracentral nucleus. It is a morphologically continuous col- 

 umn of cells giving origin to the motor fibres of the V, VII, 

 rx, and X nerves innervating viscera. The axones do not enter 

 their nerve-roots directly, as a rule, but through the medium 

 of the fasciculus longitudinalis dorsalis. Some appear to 

 cross to the opposite side. Dendrites from the nucleus come 

 into relation ^ith axones of the lobus vagi. 



The general cutaneous nucleus is the homologue of the 

 dorsal cornu. It is tne primary centra for the general cuta- 



