446 



THE BRAIN OF MAMMALS, BY TH. MEYNERT. 



upon a confusion with fibres belonging to the descending root 

 of the fifth, which certainly lie very close to the emergence 

 of the trochlearis (fig. 251, 5). 



Fig. 250. 



Fig. 250. Transparent transverse section from the inferior half of 

 the testes and the uppermost layers of the pons in Man. A, The 

 aqueduct, surrounded by the grey substance of the central cavities ; 

 Q, the ganglion of the testes ; B x , decussation of the brachia of the 

 testes ; S, peduncle of the testes (fillet) ; m, upper lamina of the fillet 

 from the nates ; BA, the connecting arm (processus a cerebello ad 

 cerebrum) decussating with that of the opposite side ; VS, spinal-cord 

 fasciculi of the posterior division of the pons, situated internally to 

 the connecting arm ; 4, transverse section of the root of the fourth 

 nerve ; L, posterior longitudinal fasciculus ; 5, the cells of the sub- 

 stantia ferruginea ; 5', descending roots of the fifth nerve, with vesi- 

 cular cells of origin ; P, continuation of the crusta into the anterior 

 division of the pons ; Trp, deeply situated transverse fasciculi of 

 the brachia of the pons ; Trs, superficial transverse fasciculi of the 

 brachia of the pons. 



The grey substance of the central cavities as high as the 

 nates includes, besides the centre of origin of the motor nerve 

 roots in the median line, a laterally situated sensory tract, to 



