Tail regeneration in normal and neural crest-extirpated tadpoles. (A) A tadpole developed from a neural fold-extirpated embryo. The white bracket indicates the tail region with its pigment cells and dorsal fin depleted. The inset is a sketch of a stage 15/16 embryo, the green area marking the posterior neural fold removed. (B) A tadpole immediately after amputation. The white bracket indicates the region free from melanophores. (C) The same tadpole as in (B), 4 days after tail amputation, arrowheads indicate amputation level. (D) A tadpole with reduced number of melanophores close to the tail amputation level, 2 days after amputation. Arrowheads indicate amputation level. (E) A control tadpole, 4 days after amputation. White arrowheads indicate amputation level. (F, G) In situ hybridization of mitf (F) and dct (G) in neural fold extirpated tadpoles. Brackets mark the melanophore-free region of the tail. Scale bars, 500 μm.