Gastrulation and Primary Organ Formation in Birds | Embryology

In this article we will discuss about the gastrulation and formation of primary organs rudiments in birds. The earlier stages of the discoidal cleavage in the eggs of reptiles and birds resemble essentially the cleavage in meroblastic eggs of the fishes. The blastoderm is several cell layers thick, and lies over a "sub-germinal cavity." At a later stage of development [...]