Larval Ambystoma tail regenerates, innervated by the intact spinal cord, were cultured with their epidermal covering in modified Parker's medium (CMRL-1415) and the morphological integrity of the explanted regenerates was maintained with consistent success. The results show that the larval urodele tail blastema is capable of undergoing growth and differentiation when isolated in vitro and regeneration follows the normal in vivo pattern. A diffuse aggregate of blastema cells, which extended

more »

... lly from the cut end of the notochord at the time of explantation, underwent differentiation in vitro in the presence of the regenerating spinal cord. The importance of the nerve in regeneration is discussed in relation to the in vitro system.