Eunotioid is one of nine morphology categories that we use to provide a visual aid in identification. These categories are artificial (not strictly evolutionary).
Valves with bilateral symmetry (symmetric about a line)
Valves often asymmetrical to the apical axis
Raphe system is short and provides weak motility
Raphe located on valve mantle and face
Cells may possess 2 or more rimoportulae (labiate processes)