What is "bathynellacea"

Bathynellacea is an order of crustaceans which live interstitially in groundwater. Some species can tolerate low salt concentrations, and at least one African species is a thermophile, living in hot springs and tolerating temperatures up to . Bathynellaceans are minute, blind, worm-like animals with short, weak legs, reaching a maximum size of . They are found on every continent except Antarctica, although they are missing from some islands, including Fiji, New Caledonia and the Caribbean islands. There are two families, Bathynellidae and Parabathynellidae; a third family, "Leptobathynellidae", is considered a synonym of Parabathynellidae.