Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 434, Figs. 28-29: L. Permian, N. central Siberia, Russia. 28, Longitudinal section, x 103; 29, longitudinal section showing mesolamellar wall, x 80 (from Gerke, 1961).