Description Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 393, Figs. 1-2: M. Eocene (Lutetian), Grignon, France. Side and apertural views of hypotype (USNM, Cushman Coll. 24116).