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Genus Hyalosphenia

Shell is rounded, ovoid or elongated elliptical or flask shaped, laterally compressed, aperture variable from linear to strongly curved, with or without thickened lip. Shell hyaline or slightly yellowish, with a smooth organic surface (exception: Hyalosphenia punctata which has a punctuated surface). Some species contain symbiotic zoochlorellae in cytoplasm. Ecology: freshwater, moss, soils. Type species: Hyalosphenia ligata (Tatem, 1870)