anatomical entity in vitro disaggregated/reaggregated ectoderm treated with activin xenopus_anatomy_in_vitro NF stage 8 ectoderm of Xenopus laevis embryos that have been cut and disaggregated. The cells have been treated with activin at a concentration to induce endodermal tissue. Afterwards the reaggregated cells have been cultured until control sibling embryos reach stage 12/13. XAO:0003009