Phylum Foraminifera d'Orbigny, 1826 see Subphylum Foraminifera d'Orbigny, 1826 Class Miliolata Saidova, 1981 - porcelaneous foraminifers Subclass Miliamminana Mikhalevich, 1980 Order Schlumbergerinida Mikhalevich, 1980 Family Sigmoilopsidae Vella, 1957 Subfamily Sigmoilopsinae Vella, 1957 Genus Sigmoilopsis Finlay, 1947 Sigmoilopsis arenata (Cushman, 1921)