Light micrograph of Synchaeta sp. rotifer swimming. Synchaeta is a fast-swimming planktonic rotifer characterised by an extremely thin transparent cuticle and, in addition to the corona, two 'ears' or auricles bearing groups of cirri which further aid swimming. Synchaeta rotifers feed predatory on small aquatic organisms. Microscopic contrast technique : Differential interference contrast. Magnification 180x when printed 10 centimetres wide.