A Redescription of Rhyncheta cyclopum Zenker (Ciliatea, Suctorida)*

SYNOPSIS Rhyncheta cyclopum Zenker (Ciliatea, Suctorida) is described from Cyclops albidus and C. viridis occurring in small lakes in Cheshire. The adults have elongated or irregularly spherical bodies which are rounded apically and flattened basally. There is usually a single primary tentacle which is variable in position, length, and activity. Additional tentacles in various stages of growth and resorption may be present, and an account of these processes is given. The body is attached to the host by a short stalk. The barrel-shaped embryos are produced by a rapid or multiple endogenous budding. The presence of the stalk and supernumerary tentacles are described for the first time, and it is considered that these, together with other features, warrant a redescription of this species. The taxonomic relationship of R. cyclopum to other species of Rhyncheta is considered and a probable connection of the tentacle form in this suctorian with its possible food source is discussed.