PAPIO O'NOCEPHALUS 



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caudal extremity of the pontile nuclei ( PN ). Another feature of this level is 

 the gradual diminution in size of the fourth ventricle now approaching its 

 cephalic extremity and about to join the aqueduct of Sylvius. Its roof is 



FIG. 150. BABOON. LEVEL OF THE EMERGENT FIBERS OF THE SIXTH NERVE AND 

 THE CAUDAL FIBERS OF THE PONS VAROLII. 



GOW, Ventral Spinocerebellar Tract; mcp, Middle Cerebellar Peduncle; mf, Mesial Fillet; nab, Abducens 

 Nucleus; nbe, Nucleus of Bechtercw; nr, Nucleus of Rolando; n6, Abducens Nerve; N'7, Facial Nerve; pn, 

 Pontile Nuclei; pns, Pons Varolii; pv, Pyramid; ref. Reticular Formation ;scp, Superior Cerebellar Peduncle; 

 so, Superior Olive; trp. Trapezoid Body; tur, Tractus Uncinatus of Russel (Hook Bundle); ver. Vermis 

 Cerebelli. [Accession No. 150. Section 25T. Actual Size 22 X 16 mm.] 



formed by a thin medullary layer, the superi(jr medullary velum, resting upon 

 which is the central portion of the vermis of the cerebellum (Ver ). 



