Ingolfiellidea

Ingolfiellidea is a small suborder of amphipods with only two families, Ingolfiellidae and Metaingolfiellidae. They are small, vermiform (worm-like) animals that live "in the soft mud of the deep-sea floor, as well as in high mountain freshwater river beds, or in subterranean fresh, brackish and marine interstitial waters of continental ground waters and continental shelves".