Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 45, Figs. 5-6: Holocene, Antarctic, at 3,410 m. 5, Apertural view, x 105; 6, side view, x 60 (from Wiesner, 1931). courtesy of Michael Hesemann https://foraminifera.eu
