In girdle view, the valves take on a rectangular shape and have short, horn-like protrusions at their corners. These protrusions end in rounded tips. The cells are connected in chains by two spines. One spine originates from just inside or slightly away from each of the horn-like protrusions. To create a chain, the two spines on one cell interlock with those on the adjacent cell. Starting from the cell’s surface, the spines initially diverge, but as they extend outward, they curve back in towards the center of the valve. The tips of these spines are divided and can be hooked. A healthy cell contains numerous plate-like chloroplasts, and the prominent nucleus is positioned at the center of the cell.