634 Journal of Comparative Neurology and Psychology. 



The following figures require little comment in addition to the 

 description given beneath each. The sensory and motor roots now 

 run on to their places of exit, the motor in front of the sensory. Of 

 the motor root bundles, the one which is chiefly composed of decus- 

 sating fibers, bundle z, lags behind the others, remains close to the 



Vmot cr. 



Fig. 29. The third section of this series ventral to the last. X 20- The 

 heavy lines to the left mark the outer surface of the brain. Description in the 

 text. 



sensory root and leaves the brain as a separate rootlet in this foetus. 

 Of the mesencephalic root the bundle c joined the sensory root in 

 Fig. 29, the bundle h enters the sensory root in Eig. 30, while the 

 bundle a appears as three small compact bundles, the last of which 

 is seen joining the sensory root in Fig. 31. The relations of the 



