RECONSTRUCTION OF LEMUR MONGOZ 



75 



termed the "waist of the trigeminal nucleus." At its cephalic extrem- 

 ity the nucleus increases in all its diameters as it prepares to meet the 

 entering mass of fibers constituting the dorsal root of the Gasserian gan- 



FIG. 36. VENTRAL SURFACE OF GRAY MATTER OF BRAIN STEM, LEMUR MONGOZ. 



Key to Diagram, cochlear, Cochlear Nucleus; inf. olive. Inferior Olive; lat. gen. body. Lateral Genicu- 

 late Body; meso-cen. body. Mesial Geniculate Body; pontile, Pontile Nuclei; ret. form.. Reticular 

 Formation; subst. nigra. Substantia Nigra; sup. olive, Superior Olive; vent, gray col.. Ventral Gray 

 Column. 



ghon. The nucleus extends somewhat above the entering fibers in order to 

 afford relay cells for the short ascending arms of the incoming axons. 



The Inferior Olivary Body 



The reconstruction of the inferior olivary body in lemur consists in 

 large part of the dorsal and ventral accessory olivary nuclei. The main mass 

 of the inferior olive seems to be a later addition, developing in a position 

 between the two accessory nuclei as a new structure presenting in the higher 

 forms a saccular fundus and two branches. 



