SummaryThe molecular as well as the electronmicroscopic appearance of elastic tissue is reviewed. The findings in the connective tissue naevus reported in this paper of parallel, partly granular fibrils, with the granules to some extent opposite each other, in the abnormal elastic fibres are described. Their significance for the fine structure of normal skin elastic fibres is discussed.With the aid of the suggested mode of formation of a similar elastomer, resilin, as well as what constitutes form in biological tissue, the implication of the above findings for the formation of elastic tissue in the skin is considered.