Macrotheca Waagen 1880, previously known only from the Salt Range of Pakistan and from Timor, and Toxeumorphora Shimanskiy, previously known only from the Ural Mountains, have been identified in the Permian of northern East Greenland. The new specimens are assigned to the order Toxeumorphorida which is transferred to the class Hyolitha. The class Xenoconchia tentatively proposed by Shimanskiy two decades ago to include the toxeumorphorids is abandoned. Macrotheca almgreeni n. sp. is described. Mollusca, Hyolitha, Toxeumorphorida, Xenoconchia, Permian, Greenland.