Shelled amoeba up to 5 mm, with brown opaque organic shell with single aperture from which extend branching pseudopodia which are not granular, may fuse again but do not form a reticulum. Shell egg-shaped or variously lobed. Cytoplasm multinucleated. Produces flagellated gametes / swarmers. Marine, reported world-wide, affinities with foraminifera and shelled filose amoebae previously proposed , but not currently substantiated.