TIIF I^.RAI\ OI- MODERN MAN 



831 



diminislR'cl. Tlu' cakIciu'i' oI the iiilcnor and supcrKir cdIIr-uIi 111 tlir midhraiii 

 ot |jrimatc's, indicated not l)\ expansion hut the re\c'ise, li.irnislies a con- 

 \'ineing ret'()rd ol an t-\()hit lonal process. 



MG. 354. MAN. LE\ EL OF THE SLPEKIOK COLLICILUS. 

 CEN, Central Gr:iy Matter; ci', Ciribral Peduncle; err, Ontral Tegmental Tract; mf. Mesial Fillet; mob. 

 Mesial Geniculate Body; noc. Nucleus Oculnmotorius; nru, Nucleus Ruber; n3, Oculomotor Nerve; pd, 

 Predorsal Bundle; I'l., Posterior Longitudinal Fasciculus; Kii, Reticular Formation; rst, Rubrospinal Tract; 

 SBN, Substantia Nigra; sc, Superior Colliculus; si>r, Spinothalamic Tract; tmt, Tractus Mescncephalici 

 Trigemini. [Accession Man. Section (.', 64-. Actual Size 30 X 14 mm.] 



The central gray matter (Cen), which .surrounds l[ic aqueduct of 

 Sylvius, in its ventromesial portion contains a large nuclear aggregation, 

 the nucleus oculomotonus iNoc). From tins nucleus the ner\e lii^ers 

 arise which supply all ol the muscles of the t'\e with the exception of the 

 external rectus and the superior ol)lic[ue. The nucleus is noteworthy because 

 ol the dense oculomotor decussation and commissural connections. This con- 

 nection itself is mdicatiNc of close internuclear relationship in the interest of 



