(ofCirculus nicholsoni A. M. Strong & Hertlein, 1939)Strong, A. M. & Hertlein, L. G. (1939). Marine mollusks from Panama collected by the Allan Hancock Expedition to the Galapagos Islands, 1931-1932. <em>Allan Hancock Pacific Expeditions, University of Southern California Press, Los Angeles.</em> 2(12): 177-245, pls 18-23.[details] Available for editors [request]
MolluscaBase eds. (2024). MolluscaBase. Episcynia nicholsoni (A. M. Strong & Hertlein, 1939). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=575491 on 2024-05-01
original description(ofCirculus nicholsoni A. M. Strong & Hertlein, 1939)Strong, A. M. & Hertlein, L. G. (1939). Marine mollusks from Panama collected by the Allan Hancock Expedition to the Galapagos Islands, 1931-1932. <em>Allan Hancock Pacific Expeditions, University of Southern California Press, Los Angeles.</em> 2(12): 177-245, pls 18-23.[details] Available for editors [request]
basis of recordKeen, A. M. (1971). Sea Shells of Tropical West America. Marine mollusks from Baja California to Peru. ed. 2. Stanford University Press. xv, 1064 pp., 22 pls.[details]
additional sourcePilsbry, H. A. & Olsson, A. A. (1952). Vitrinellidae of the Panamic Province: II. <em>Proceedings of the Academy of Natural Sciences of Philadelphia.</em> 104: 35-88, pl. 2-13. page(s): 70 [details] Available for editors [request]