original descriptionOldroyd, T. S. (1921). New Pleistocene mollusks from California. <em>The Nautilus.</em> 34(4): 114–116, pl. 5, figs. 8-13., available online athttps://www.biodiversitylibrary.org/page/27059897 page(s): 116, pl. 5, fig. 8 [details]