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 development of the branchial region in vertebrates is no less dependent on the cooperation of parts of different origin than is the mouth region. The leading part in the development of this area belongs to the endoderm. The endodermal cavity in this region, from its beginning, is distended in a transverse direction. In amphibians it is derived from the [...]