 Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the "World List of Marine Acanthocephala", "World List of Actiniaria", "World Amphipoda Database", and so on.As of December 2018 there were 60 such taxonomic subregisters, including a number presently under construction.A second category of subregisters comprises regional species databases such as the "African Register of Marine Species", "Belgian Register of Marine Species", etc., while a third comprises thematic subsets such as the "World Register of Deep-Sea species (WoRDSS)", "World Register of Introduced Marine Species (WRiMS)", etc.