In this article we will discuss about the development of general body form of vertebrates. While the various organs are being formed, the shape of the embryo as a whole undergoes far-reaching changes. During the period of organogenesis, in the case of the vertebrate embryo, the main changes are: i. Elongation of the body. ii. Formation of the tail. iii. [...]
The changing appearance of the embryos, especially during organogenesis, invites the distinguishing of certain stages which can be referred to when it is desired to indicate how far an embryo has progressed in its development. Tables of "normal stages" have been worked out for a number of species of animals, especially those that are most often used for research. In [...]
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 [...]