part of ends during starts during mesonephric kidney xenopus_anatomy adult kidney UBERON:0000080 Wolffian body mesonephros urniere opisthonephros XAO:0000141 A visceral organ which provides osmoregulation and waste excretion for tadpoles through adult stages in Xenopus. The mesonephros starts to develop at NF stage 39, then during feeding stage tadpoles through metamorphosis replaces the embryonic pronephros as it degenerates. death trunk adult kidney NF stage 39