"A History of Infusoria, including the desmidiaceae and diatomaceae, British and Foreign" by Andrew Pritchard, illustrated with 40 plates - Whittaker, London - 1861 fourth edition - 18cmx15cm - condition: very good, rebound in fine half leather binding, with decorative spine, name to ffep, all plates present, minor foxing An important 19th century handbook on infusoria Infusoria is a word used to describe various freshwater microorganisms, including ciliates, copepods, euglenoids, planktonic crustaceans, protozoa, unicellular algae and small invertebrates. Some authors (e.g., Bütschli) have used the term as a synonym for Ciliophora. In modern, formal classifications, the term is considered obsolete; the microorganisms previously and colloquially referred to as Infusoria are mostly assigned to the kingdom Protista. In other contexts, the term is used to define various aquatic microorganisms found in decomposing matter