Plate XIII. as, aqueduct of Sylvius; bi, brachium of posterior colliculus; 

 cer, occipital portion of cerebral hemisphere; eg, central gray matter; 

 ci, nucleus of posterior colliculus; dbc, decussation of brachium con- 

 junctivum; ddt, dorsal tegmental decussation (Meynert); dvt, 

 ventral tegmental decussation (Forel); flm, medial longitudinal 

 bundle; Ig, laminated gray matter of tectum penetrated by com- 

 missure of posterior colliculi; 11, lateral lemniscus; Im, medial lemnis- 

 cus; ndr, dorsal nucleus of the raphe; ni, interpeduncular nucleus; 

 nIV., nucleus of the trochlear nerve; npo, nuclei of the pons; p, 

 pyramidal tract; po, pons; rmes, mesencephalic V. root; sp, stratum 

 profundum; tg, mamillo-tegmental tract; tr, rubro-spinal tract; 

 tt, tecto-spinal tract; tti, tegmental tract of interpeduncular nucleus. 



