Gastrulation in Xenopus:

Epiboly of the Animal Cap

The sequence of scanning electron micrographic images at the right provides an overview of the behavior of the animal cap during Xenopus gastrulation. Each image is a fracture through the roof of the blastocoel at various times during gastrulation. Note the thinning of the entire tissue, which involves radially directed intercalation of deep cells and flattening of the superficial epithelium.

Scanning electron micrographs of the animal cap during epiboly