The European register is derived from the MarBEF (http://www.marbef.org) database Aphia. Aphia was developed for the European Register of Marine Species, or ERMS (http://www.marbef.org/data/erms.php), and now includes additional species lists, such as from the Indian Ocean and the Antarctic. Aphia, and the classification adopted, are described on the ERMS site. The NW Atlantic register is a product of the Atlantic Reference Centre (ARC) of the Huntsman Marine Science Centre (http://www.huntsmanmarine.ca). Classification also follows Aphia. This register is an outgrowth of species lists of the ARC's Bay of Fundy Species Information (http://gmbis.marinebiodiversity.ca/BayOfFundy/search.html) and other web products, expanded to the Gulf of Maine, Canadian Atlantic, and finally NW North Atlantic species. These lists are posted temporarily at http://gmbis.marinebiodiversity.ca/nonNARMS. ARC species lists are based on paper and electronic published, in-press, and unpublished literature, and the ARC museum database. Though some sources and species were undoubtedly missed, an attempt was made to make these lists comprehensive and authoritative species registers.