[Regeneration of photoreceptor organs in freshwater planarians at different levels of accumulation of natural methylmercury compounds].

The effects of natural methylmercury compounds on regeneration of photoreceptor organs were studied in three freshwater planarians: Polycelis tenuis, Dugesia lugubris, and D. tigrina. Accumulation of methyl mercury in the planarian body suppressed regeneration of P. tenuis with numerous photoreceptor organs to a greater extent than in two other planarians that have only two eyes. High methyl mercury concentrations inhibited the restoration of photoreceptor organs in asexual and sexual D. tigrina races.