Shells pseudotwochambered (with long tubular second chamber around proloculus) or derived from it (pseudomultichambered, multichambered in higher representatives, but often with the initial tubular part preserved during 1 -2 volutions), with different coiling types - glomerate (very often, especially at the initial part), planospiral (more often at the adult stage, being initially streptospiral), sometimes biserial in the last part, trochospiral one also occur; pseudochambers formed by constrictions of the outer shell wall or by the short septula, chambers in multichambered forms usually bearing the primitive features, showing their origin from the tubular one (being somewhat irregular, with short right or only slightly curved septa lacking characteristic for Rotaliata's septa thickenings at the septal ends), chambers in advanced groups becoming more regular; integrative systems - primitive canal systems in some advanced tubular forms; wall insufficiently studied, monofontinal, agglutinated (often with ferrugenous cement) or microgranular in lower forms (Ammodiscana), in higher subclass (Spirillinana) completely secretious, radial, may be pitted by regular pseudopores (according to the literature), layers of growth are not formed, in ancient forms often two layers are marked - microgranular and radial, in Involutinida - usually radial, in recent Spirillinids - radial crystal units act optically as a single crystal, outer sculpture and inner pillars well developed; growth of tubular part uninterrupted, occurs by lateral accretion along the edge of the chamber, in multichambered forms unclear; aperture terminal (in trochoid forms tending to displace on the umbilical side), always simple, never forming inner apertural structures, single or (rarely) multiple (in advanced multichambered forms), in multichambered trochoid forms outer apertural structures sometimes present (valvular flap, T-shaped or S-shaped plate), additional apertures often occur; agamonts of recent Spirillinata homokariotic (their proloculus larger then that of the gamonts - the reverse correlation), gametes amoeboid; bottom, mostly free living forms. Cm - Holocene.