The ability of regulation, including restoration of the missing parts, to normalize the development, is a fundamental characteristic of living systems. However, until recently, representatives of the group Spiralia (animals with spiralian development) have been considered a typical example of determinative development. Meanwhile, studies in recent years give reason to speak about the presence of inductive cell-cell interactions at the early stages of Spiralian embryo development. In this paper, for the first time, we have shown the development of the polychaete Alitta virens blastomeres isolated at different stages. The results indicate the inability of A. virens partial embryos of regulation to form a whole normal larva and a high degree of autonomous determination of trochoblast cells. At the same time, the findings support probable early induction of blastomere D and acquisition of competence by blastomere D to further development of trochoblast ciliated cells.