This species closely resembles its relative, Heterostegina. This individual was collected off Okinawa. Image courtesy of Maria Holzmann, University of Vienna. This image first appeared in J. Foram. Res. 33:277-284 and is used with permission.
Image source: Cushman, J.A. 1914. A Monograph of the Foraminifera of the North Pacific Ocean. Part IV. Chilostomellidae, Globigerinidae, Nummulitidae. Bull. U.S. Nation. Mus 71: vi+46 pp.+19 pls.