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Genus Amphitrema

Shell is elliptic in the broad lateral view, compressed in the narrow lateral view, covered by exogenous particles (diatom frustules, flagellate cysts etc.). A patterned cement network can be seen sometimes by scanning electron microscopy. Two elliptic apertures, with or without short collar, are located on the opposite sides of the shell. Type species: Amphitrema wringhtianum Archer, 1869