THE MEDULLA OBLONGATA. 



371 



yet, non-meduUated, and only those appear distinctly which arise from the 

 nuclei of the posterior columns. 



By reason of the two decussations the appearance of the cross-section 

 changes materially. In addition, the gray matter, as presently to be de- 



Ventriculus 

 ieriius 



ZTViscIi^nhirn. 



Mitidhirn 



Jv. Irochlcarts^ 

 Hinierhirn. 



JV'aMarn. 



JWitte aeust 





Jtuckemyiark . 



Fig. 236. — The hind- and after- brain exposed by removal of their roof. 

 Velum medullare anticum and cerebellum still visible. Velum meduUare posti- 

 <:um has been removed along the dotted line, 6a. ZwischenMrn, Thalamen- 

 cephalon. Mittelhirn, Mesencephalon. Binterhirn and Kleinhirn, Pons and cere- 

 bellum. Nachhirn, Medulla oblongata. Buckenmarlc, Spinal cord. Hirnschenkel, 

 Cerebral peduncle. Bindearm, Peduncle of cerebellum. 



scribed, also changes its form, and new masses of it appear in the medulla; 

 three of these — the two posterior nuclei and the olive — we have already 



