original description
Gabb, W. M. (1860). Descriptions of new species of American Tertiary and Cretaceous fossils. <em>Journal of the Academy of Sciences of Philadelphia, Second Series.</em> 4: 375-404, pls. 67-69., available online at https://biodiversitylibrary.org/page/36862263
page(s): 388, pl. 67, fig. 53 [details]
additional source
Harris, G. D. (1895). New and otherwise interesting Tertiary Mollusca from Texas. <em>Proceedings of the Academy of Natural Sciences of Philadelphia.</em> 47: 45-88, 9 pls., available online at https://www.biodiversitylibrary.org/page/26323100
page(s): 49-50, pl. 1, fig. 10-10a [details]
From editor or global species database
Original description Subquadrate; beaks very small; umbonal slope wide, umbonal ridge rounded; anterior margin semicircular, basal regularly arcuate, posterior subbiangular; surface marked by numerous, large, transverse folds, which commence at the anterior margin, but disappear before reaching the middle of the shell, leaving the rest almost perfectly smooth, (this is not the result of attrition); interior margin very delicately crenate, anterior muscular impression semilunar, posterior subquadrate. Dimensions.- Length .5in, width .6in. [details]