RECONSTRUCTION OF HYLOBATES HOOLOCK 449 



the uppermost level of the mahi nucleus by fusing with the dorsal branch 

 at its mesial extremity. The arrangement of the nucleus is similar to that 

 found in other primates. Its deep surface lies embedded in the reticular for- 



FIG. 213. \ ENTRAL SURFACE OF GRAY MATTER OF BRAIX STEM, 



HYLOBATES HOOLOCK. 



Key to Diagram, lat. gen. body. Lateral Geniculate Body; pontile, Pontile Nuclei; ret. form.. Reticular 



Formation; sup. olive, Superior Olive; vent. coch. and ventral cochlear, Ventral Cochlear Nucleus. 



mation and the dorsal extremities ot its two laminae are turned dorsally at 

 their mesial extremities. The hihis opens toward the contrahiteral inferior 

 cerebellar peduncle. 



The Reticular Formation 



The ventral surface of the reticular formation in its oblongatal and 

 lower pontile portions is, to a great extent, in contact with the inferior oli- 

 vary nucleus. Lateral to the fundus of the olive the reticular formation 

 approaches the surface of the stem and is luicovered except by peripheral 

 fiber bundles. Dorsal to this uncovered area is the substantia gelatinosa 



