Abstract
1. Our study was conducted with series of Pal-carmine stained transverse sections of the brains of a pigeon, a japanese bush-warbler, a gull, a baby crow, an owl and cock as materials.
2. In a bird's brain, the fasciculus solitarius is fully developed, but the facial nucleus is located far up in a cranial position, and there is no trace that it has ever moved down caudally.
3. In a bird's brain, the pyramidal tract is lacking altogether, yet the facial nucleus is generally situated in much the same position as occupied by it in mammals, the pars 1 of intrapontine facial nerve being found formed in some cases only.
4. There has been no observation revealing that the facial nucleus has been particularly drawn toward the extrapyramidal tract.
5. Concerning the question whether the facial nucleus is displaced toward the nucleus of the descending trigeminal root, it may be mentioned that the relative position of the two organs above, if the position of the superior olive is taken as standard, is somewhat unlike from bird to bird.
6. In consideration of the above, we find it impossible to recognize the applicability of the neurobiotaxis theory in the case of birds as little as in the case of mammals.
