Stentor amethystinus (Protista: Ciliophora: Heterotrichida), a common protozoan member of fresh-water plankton in Australia
Large numbers of a brown to violet ciliate can often be seen in freshwater lakes and billabongs in Australia. Uninterpreted records by light microscopy and electron microscopy are provided. The ciliates are identified as Stentor amethystinus Leidy, 1880. Despite the abundance of this species, this is a new record for Australia.