622 "Journal of Comparative Neurology and Psychology. 



cephalad its bundles are cut obliquely and reach in this section only 

 as far as the internal or dorsal border of the pons. The outline of 

 the motor nucleus is indicated by a dotted line and it is evident that 

 the greater part of the motor root comes from this nucleus. Dorsal 

 to the nucleus are seen fibers passing over it and turning down 

 parallel with the motor bundles. In adjacent sections it is clearly 



Fig. 19. Human foetus, 27 cm. Transverse section of the trigeminal roots on 

 the left side. Weigert stain, x 25. Camera drawing. 



seen that these fibers form definite bundles which go out with the 

 motor root. They are the crossed fibers of the motor trigeminus. 

 These are all the fibers which enter the motor root in this specimen. 

 The mesencephalic root continues in the transverse plane from the 

 sensory root to a point dorsal to the motor nucleus, where it turns 

 forward to go through the isthmus to the tectum mesencephali. The 

 oonnection of the mesencephalic bundle with the sensory root in this 



