"The Xenopus Anatomical Ontology describes Xenopus anatomy and development as a controlled vocabulary of terms, organized in a graphical structure. Tissues are shown as being part of other tissues and the timing of their development is indicated by start and end stages. The lineage of tissues is represented by develops from relationships between different tissues at different developmental stages. Many items have been classified according to the Common Anatomy Reference Ontology. The ontology is listed at the Open Biomedical Ontologies (OBO Foundry)."