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 [...]
When the epidermis is first segregated from the other parts of the ectoderm (neural plate, neural crest) during the process of neurulation, it is still a very complex rudiment. Most of it becomes the epidermis of the skin, but in addition, a number of other structures are derived from it. Some of these are – the lens, the cornea, and [...]