The cells appear in two shapes when viewed from the top (valve side): triangular or rectangular. In the center of the top of the cell, there is a curved line that is divided into three parts. Three straight and thickened lines (called costae) separate the three corners of the top of the cell from the center. Within these triangular areas, there are smaller holes (areolae) that form a pseudocellus. The top of the cell has three openings (labiate processes), and inside these openings is a well-developed structure that is attached to a stalk.The cells can be found alone or in irregular chains, with neighboring cells connected by mucus secretions through the pseudocelli.