Mariella (Mariella) lewesiensis (Spath, 1926) from the Cretaceous of the Hobetsu district, south-central Hokkaido, is described. It is represented by a large specimen, from which a question may arise about the previous view of dimorphism. This species is not directly related to M. (M.) dorsetensis (Spath, 1926). It has some affinities with M. (M.) cenomanensis (Schluter, 1876).
