Kingdom Animalia Linnaeus, 1758 - animals Phylum Nematoda Gegenbaur, 1859 - round worms Class Chromadorea Inglis, 1983 Subclass Plectia Hodda, 2007 Superorder Monhysterica Hodda, 2007 [monotypic] Order Monhysterida Filipjev, 1929 Suborder Monhysterina De Coninck & Schuurmans Stekhoven, 1933 Superfamily Sphaerolaimoidea Filipjev, 1918 Family Xyalidae Chitwood, 1951