In this article a new mollusc is treated for the fauna of the Netherlands. A single valve of Thracia papyracea (Poli) was found along the coast south of Katwijk aan Zee on 7 March 1936 in shell-sand. The specimen, although in a young state is quite recent with a shining surface; seen under a high power it appears to be distinctly granulated. Fossil remains are found in various strata, especially in the Eem beds.