Synchaeta pectinata rotifer, light microscopy. A Peridinium dinoflagellate (yellow) can be seen digesting in the rotifer's stomach. The Synchaeta head has a crown of cilia that draws a vortex of water into the mouth. S. pectinata is a small predator, approximately 0.45 millimetres in length. Peridinium are 30-70 micrometres in length and covered in a thick plate armour of thecal plates. Filmed with dark-field illumination.