Amphibian Embryology Tutorial
Glossary and graphical illustration of oogenesis, cleavage, gastrulation and neuraltion, primarily in Ambystoma and Xenopus, from the University of Wisconsin, Madison.

Xenbase
Collection of information on early amphibian development, methods including immunohistochemistry, in situ hybridization, molecular markers, based on Xenopus, as part of the WWW Virtual Library.

Molecular Mechanisms of Cell Division and Development
Research on the molecular biology of Xenopus embryonic development at the Institut de Physiologie et de Chimie Biologique, Strasbourg, France.