Hofker, J. (1964). Foraminifera from the tidal zone in the Netherlands Antilles and other West Indian Islands. Studies on the Fauna of Curaçao and other Caribbean Islands. vol. 21., available online at (http://www.repository.naturalis.nl/record/506177) page(s): p. 111 fig. 272
Image source: Cushman, J.A. 1930. The Foraminifera of the Atlantic Ocean. Part 7. Nonionidae, Camerinidae, Peneroplidae and Alveolinellidae. Bull. U.S. Natl. Mus. 104. Note: According to Le Calvez ( 1977), Cushman's description (fig. 9) of E. discoidale does not fit with d'Orbigny's species: Fig. 8 reproduces d'Orbigny's drawing.