Cercyridae with an extra, caudal gonopore; ovaries communicate with sacs which are cinnected with the oviducts; one pair of testes, occupying the entire space between dorsal and ventral body surface; penis unarmed.
The genus contains the following species: Oregoniplana opisthopora Holmquist and Karling, 1972, O. pantherina Sluys, 1989a.