[Influence of zinc chloride on the inversion of sexes and the development and differentiation of additional germ elements inEisenia foetida Sav. (Oligochaeta, Lumbricidae)].

We have studied the effect of zinc chloride, known for the morphogenetic changes it causes in embryos of Vertebrates and Invertebrates, on the sexual differentiation ofEisenia foetida, a hermaphrodite with separate gonads.There was evidence that zinc chloride causes inversions in the testes and ovaries. It also helps the development and survival of a germ line outside the normal gonadal segments, in the presumptive male territory as well as in the presumptive female one. We have studied the differentiation of this additional germ line.The conclusions drawn from this study emphasize the difficulties of applying the theory of self-differentiation of the female line to the case of earthworms.