PLATE 2 



EXPLANATION OF FIGURES 



5 to 10 Sagittal sections taken in order passing from the right to the left 

 sides of the brain stem of pigeon 126. Because of lack of detailed knowledge of 

 the thalamic and mesencephalic nuclei and fiber tracts in the bird, these parts 

 are not labeled. Camera-lucida drawings. X 6. 

 Ce., cerebellum O.ch., optic chiasma 



Hy., hypothalamus O.L., optic lobe cortex 



III., oculomotor nerve O.N., optic nerve 



.1/., midbrain P.C., posterior commissure 



M.O., medulla oblongata V., ventricle of the optic lobe 



N., region of broken, unstained, ap- 

 parently softened or necrotic tissue 



34 



