Newly discovered fossils from Eocene rocks of the Quimper Sandstone, Washington, USA, constitute the first reported occurrence of the albuneid genus Lophomastix Benedict, 1904, in the fossil record. Lophomastix and the closely related genus Blepharipoda Randall, 1839, are thought to be basal taxa within the decapod family Albuneidae Stimpson, 1858, based upon possession of primitive trichobranch gill structures. The occurrence of Lophomastix antiqua new species in Eocene deposits indicates that the genus is at least as old as the more derived genus, Albunea Weber, 1795, as would be expected for the basal taxon within the family. Based upon examination of type material, Blepharipoda brucei Rathbun, 1926, is herein removed from that genus and placed within the Paguroidea as Pagurus brucei (Rathbun, 1926) new combination.