Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 229, Figs. 5-7: M. Carboniferous (Moscovian), USSR. 5, 6, Side and top views, x 40 (from Reytlinger, 1950); 7, diagrammatic longitudinal section, enlarged (from Cummings, 1956). courtesy of Michael Hesemann https://foraminifera.eu