Description of Frontonia angusta:
Species in this genus of pecinuline ciliates range from 60 to 300 microns long. The cell is ovoid with an oral depression in the anterior half of the cell. The cell may be dorso-venterally flattened and may have a pointed posterior. The oral aperture is located at the bottom of this depression. The oral structures are difficult to see without silver staining the cell: on the right of the depression there is a undulating membrane and on left there are three membranelles. Regular somatic ciliation covers the entire cell, with cilia ~10 mm long. Trichocysts occur regularly at the cell surface. Typically one, but possibly two or many contractile vacuoles occur; these may have radiating canals. The macronucleus is ovoid to reniform and centrally located. Habitat and distribution: benthic; plankton; freshwater, marine; occurrence: common.