The cells are flattened and measure between 13 to 19 µm in width. The apertures are lenticular and somewhat fused at the points where setae attach. Each valve exhibits four protuberances connected to similar knobs on neighboring cells. The valve surface is rectangular with curved angles, and the setae are attached at their insertion points. The valve mantle is relatively tall and lacks a distinct notch where it meets the girdle band. In resting cells, the girdle zone is small. Each cell contains one chromatophore.