Description of Xenophyophorea
Circumscription: Generally large (>1 cm) marine Amoebae with an agglutinated test. Cell multinucleated; waste material (stercomata) accumulate around cell within test. Cytoplasm contains barite crystals. Very little information on cell organization, pseudopodia said to be filopodial or granuloreticulopodial. Widespread and possibly significant in deep sea sediments. Ultrastructural identity: No information, identity based on gross morphology, stercomata, and barite crystals. Synapomorphy: Large marine Amoebae containing barite (BaSO4) crystals, and with adhering stercomata.