Cells drum-shaped; radiating lines absent from valve face; may be joined weakly at the edges of the valves to form chains.
Cells short and drum-shaped; numerous discoidal chloroplasts; lines on valve face radiate to the perimeter.
![[Cerataulina], lower Taieri River, X160. Photo: Otago Regional Council & Manaaki Whenua](/assets/Tools-And-Resources/Identification/algae/cerataulina160__FillMaxWzMwMCwyMDBd.jpg)
![[Cyclotella], X1000. Photo: Phil Novis, Manaaki Whenua](/assets/Tools-And-Resources/Identification/algae/cyclotella_meneghiniana_phil1000__FillMaxWzMwMCwyMDBd.jpg)