Description of Heterotrichida
provided by BioPedia
Somatic dikinetids, when singly ciliated, usually with anterior kinetosome ciliated; left serial oral polykinetids used to locomote and feed; alveolar membrane system poorly developed; many species contractile; cytopyge present; contractile-vacuolar system with collecting canals and large collecting vacuole or absent; some species are pigmented, often brightly, with pigment in specialized pigmentocysts
