[Caudal regeneration in the presence of a supplemental nerve cord grafted dorsally in Nereis pelagica L. (Annelida Polychaeta)].

In Nereis pelagica, the existence of an additional nerve cord grafted dorsally induces the differentiation on the dorsal face of the regenerate of a supernumerary area with ventral characteristics, provided the grafted nerve cord regenerates posteriorly. These results led us to think that the dorse-ventral differentiation of the body wall doesn't depend upon the nature of the stump region but is controlled by the nerve cord regenerating in the area.