part of develops from ends during starts during ectoderm animal cap inner layer neuroectoderm cranial placode XAO:0000305 xenopus_anatomy A localized ectodermal thickening that develops by apicobasal elongation of cuboidal cells in the inner layer of the ectoderm in the head of the embryos, and is involved in formation of sense organs. UBERON:0002546 cranial placodes sensorial layer embryonic structure neural plate border NF stage 13 NF stage 42