Description of Clypeolina

Test: ovoid, 2-layered, outer of opposed chitinoid valves covered with small scales, forms keel; inner a thin flexible sac closely investing the cell. Pseudostome: terminal, wide, oval or linear. Endoplasm: sometimes with zoochlorellae. Pseudopods: extremely thin. Nucleus: spherical, irregularly shaped endosome (nucleolus). Reproduction by longitudinal fission, one valve is replaced by a new one. Feeding: algivore. Habitat: oligotrophic freshwater, sediments or on plants. One rare species: Clypeolina marginata Penard, 1902.