The neural crest at the time of its formation is represented by a mass of loose cells lying dorsal to the neural tube. Almost at once after the formation of the crest, the cells of which it consists start migrating in a lateral and ventral direction from the place of their origin. As the neural crest cells move, they form [...]
The cranial nerves of vertebrates, when compared with the spinal nerves, show a great diversity in configuration, distribution, and function and the same diversity can also be noted in their development in the embryo. To start with, the two most anterior nerve pairs, nerves I (olfactory) and II (optic), are completely different in nature and cannot be in any way [...]
We will first trace the features manifest in the development of the brain in all vertebrates and then point out some of the peculiarities found in higher vertebrates, especially in mammals and in man. The anterior brain vesicle, the prosencephalon, gives rise at its anterior end to the telencephalon. The latter produces in an early stage two bulges directed anterolaterally [...]