Embryology
Early cleavage stages
Blastula formation (frog embryo)
Gastrulation (amphioxus or sea urchin)
Gastrulation (frog embryo)
Neurulation: Formation of the neural tube and neural crest
Early development in a chick, whose embryo is spread out on the surface of a massive yolk
Further stages in chick development
Human blastocyst and its implantation
Human placenta
