A long overdue taxonomic revision is performed on the family Euretidae (Hexactinellida). World literature is compiled, world type material is gathered, prepared, re-examined, measured, described and illustrated, taxonomic histories and world species distributions are provided. A generic key to the Euretidae is also provided. Of the 19 generic names associated with the Euretidae at one time or another, 16 are recognised here (Bathyxiphus, Calyptorete, Chonelasma, Conorete, Endorete, Eurete, Gymnorete, Heterorete, Iphiteon, Myliusia, Pararete, Periphragella, Pleurochorium, Ptychodesia, Lefroyella and Verrucocoeloidea). Syringidium is put into synonymy with Lefroyella; Joanella and Margaritella are synonymized with Iphiteon; two subspecies and one form are elevated to species status; three new species combinations are presented and two new species are named. Phylogenetic analysis suggests the majority of morphological euretid characters are prone to homoplasy and are not useful for phylogenetic classification. Subfamilies based on channelization and the presence or absence of key spicules are designated.

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