428 



THE BRAIN OF MAMMALS, BY TH. MEYNERT. 



fasciculi in accordance with the various peripheric termini to 

 which they pass. 4. The fourth converging series of fasciculi, 

 entering the anterior extremity of the optic thalamus, is 

 composed of fibres coming from the cortex of the gyms forni- 

 catus, thus forming the ascending pillar of the fornix, which 

 constitutes an upper peduncle of the optic thalamus (fig. 

 247, CP). After it has completed a slightly sigmoid flexure, first 



Fig. 246. 



Fig. 246. Transparent sagittal section of the Thalamus opticus of 

 Man, near its internal surface. Th, Thalamus opticus ; Qu, corpora 

 quadrigemina ; Z, the pineal gland ; H, the ganglion of the peduncle 

 of the pineal gland (Zirbelstile) ; M, corpus mammillare ; T, tuber 

 cinereum ; R, red nucleus of the tegmentum ; S, substantia nigra ; 

 A, wall of the aquzeductus Sylvii ; II, chiasma nervi optici ; C, ante- 

 rior commissure ; ///, nervus oculomotorius ; Sz, stratum zonale ; 

 J", fasciculi in the interior of the substance of the optic thalamus 

 from the inferior peduncle ; Fd, descending eras of the fornix ; Fa, 

 ascending crus of the fornix ; P, posterior commissure ; L, posterior 

 longitudinal fasciculus ; m, fasciculus passing to the tegmentum from 

 the corpus mammillare. 



curving inward away from the posterior longitudinal fasciculi, 

 and subsequently while in the substance of the optic thalamus, 

 turning somewhat outwards, it passes straight forward and up- 

 ward, and, after dividing in a forked manner, as is brought into 

 view by a frontal section, enters the upper nucleus of the optic 

 thalamus, its anterior extremity being apparent on the outer 

 surface as the tuberculum or genu anterius (fig. 247, To). The 



