In this paper two new genera of lamellibranchia are recognized from the Upper Permian beds of Western Australia. Four species are described from the Wandagee Series, while two are also recorded from the Nooncanbah Series, its northern equivalent in. the West Kimberley Division. The shells are of particular interest as they possess a wide V or chevron-shaped type of ornamentation which is rarely found on palaeozoic shells. They are edentulous, posteriorly-gaping forms, possessing close affinities with mesozoic shells of the Family Pholadomyidae. The two new genera bear a close resemblance to Permian shells recently described from Madagascar by Astre (1934) and also have many points in common with Jurassic shells from the Spiti Shales described by Holdhaus (1913) as Goniomya Agassiz and Cosmomya, gen. nov.