The observations made on a 27-year-old patient with ichthyosis, debility, psychoinfantilism, and Little's syndrome are reported. Clinically, the condition of the skin is similar to that associated with ichthyosis vulgaris. Histologically, however, the picture is largely that of ichthyosis congenita, the condition being even more pronounced than that of ichthyosis congenita mitis. This particular case may be placed within the class of transitional forms of hereditary ichthyoses, and it may thus be proved that the Sjögren-Larsson syndrome also has its 'formes de passage'. In the etiological determination of oligophrenias and infantile cerebral motor disorders it is always necessary to give attention to the probable presence of ichthyosiform conditions of the skin.