Description Loeblich, A. R., Tappan, H. N., 1987: Foraminiferal genera and their classification. Van Nostrand, Reinhold Co. New York 1728 pp. Plate 22, Figs. 10-11: Holocene, Gullmar Fjord, Sweden. 10, Exterior view of three individuals, x 50; 11, diagrammatic longitudinal section through apertmal region, showing outer opening (o), cylindrical apertmal sheath (c), constriction of opening (co), inner flattened apertmal sheath (is), lamella (1), and test outer layer (ol) and inner layer (il), about x 160 (from Dahlgren, 1962).