ArachnoididaeArachnoididae is a family of echinoderms of the order Clypeasteroida.GeneraAmmotrophus H. L. Clark, 1928Arachnoides Leske, 1778Fellaster Durham, 1955Fossulaster Lambert & Thiery, 1925Monostychia Laube, 1869Philipaster Wang, 1994Prowillungaster Wang, 1994Scutellinoides Durham, 1955Willungaster Philip & Foster, 1971