RECONSTRUCTION OF LEMUR MONGOZ 



79 



nuclear mass is divisible into a superficial, ventral layer and a deep, dorsal 

 layer, both of which are conlluent laterally and mesiaily in an area surround- 

 ing the descending paUio-pontile and palho-spinal tracts. The pyramidal 



FIG. 30. LATERAL SURFACE OF GRAY MATTER OF BRAIN STEM, LEMUR MONGOZ. 



Key to Diagram, inf. olive, Inferior Olive; lat. gen. body, Lateral Geniculate Body; meso-gen. body. 

 Mesial Geniculate Body; nucl. of burdach. Nucleus of Burdach; nucl. of deiters and n. of 

 DEiTERS, Nucleus of Dcitcrs; ret. form.. Reticular Formation; subst. gel. rolando, Substantia 

 Gelatinosa of Rolando; subst. nigra, Substantia Nigra; sup. coll., Superior Colliculus; vent, gray col.. 

 Ventral Gray Column. 



tract is separated into fasciculi by the transverse pontile fibers only to a 

 limited extent and in the main appears as a single heavy mass of fibers. 

 The pontile nuclear masses are large and their continuity is not materially 

 interrupted by the decussating ponto-cerebellar fibers. The deep layer of the 

 nuclear mass is continuous at its cephalic extremity with the substantia 

 nigra. Marked condensations of nuclear material appear laterally and 

 mesiaily. They connect the superficial and deep layers of the pontile nucleus 

 and form lateral and mesial buttresses for the substantia nigra. 



