When viewed from the valve side, the cells have a long lanceolate shape with slightly extended ends. In girdle view, these cells appear rectangular and are connected to form colonies that create broad bands. The cells have the ability to slide along each other, leading to varying colony shapes. In fixed samples, these colonies may resemble either stacked cells or long bands with minimal overlap between the cells. Each cell contains two prominent, plate-like chloroplasts, and the nucleus is centrally located.