Heterotrich ciliates, swimming or more usually attached, when attached posterior end is digitate and narrow, body expanding to a broad oral end. Adoral zone of membranelles extends around the margin of the oral end of the cell before descending into a buccal cavity. Unattached cells more rounded. Cells up to 1000 microns long. Body with numerous longitudinal kineties, and arching kineties also located on peristomial disc. Contractile. Often coloured, pink, blue, green etc.