Irregularly shaped cell, usually around 40 µm in length, with a narrow anterior hyaline margin. Frequently with a few, fine, short subpseudopodia (echinopodia) arising from the margin giving the cell a spine-like appearance. Posterior often with adhesive uroidal filaments. Cytoplasm with numerous contractile vacuoles and a spherical nucleus. No centriole-like bodies at the ultrastructural level. Cysts usually irregularly polyhedral with a thick inner wall and very thin outer layer. Only genus in the family to have cysts with pores closed by operculum. Single freshwater species, C. operculata Perin & Pussard 1979.