Abstract
Behaviour of a teratological character present in «Navicula minima» Grun. — A teratological form with curved cells like the kidneys has been isolated from a culture of Navicula minima Grun, to follow the behaviour during the biological cycle. Alternately varied cells in the morphology of the frustules appeared in the descendants, deriving from a modification more or less evident in the initial teratological character. The main cause of this phenomenon can be found in the normalization process of the frustules that has been put in relation to a probable plasticity of the cellular Silicon walls. The cells, even though more or less deformed, have given origin to auxozygotes which, having terminated their growth, have formed perfectly normal frustules.