Infusoria

• WordNet 3.6
  • n Infusoria in some recent classifications, coextensive with the Ciliata: minute organisms found in decomposing infusions of organic matter
  • ***

• • n. pl Infusoria (Zoöl) One of the classes of Protozoa, including a large number of species, all of minute size. Formerly, the term was applied to any microbe found in infusions of decaying organic material, but the term is now applied more specifically to one of the classes of the phylum Ciliophora, of ciliated protozoans.☞ (From 1913 dictionary): They are found in all seas, lakes, ponds, and streams, as well as in infusions of organic matter exposed to the air. They are distinguished by having vibrating lashes or cilia, with which they obtain their food and swim about. They are devided into the orders Flagellata Ciliata, and Tentaculifera. See these words in the Vocabulary. Formely the term Infusoria was applied to all microscopic organisms found in water, including many minute plants, belonging to the diatoms, as well as minute animals belonging to various classes, as the Rotifera, which are worms; and the Rhizopoda, which constitute a distinct class of Protozoa. Fossil Infusoria are mostly the siliceous shells of diatoms; sometimes they are siliceous skeletons of Radiolaria, or the calcareous shells of Foraminifera.
  • ***

• • infusoria A name given by Otho Fr. Müller to an indiscriminate assemblage of minute, and for the most part microscopic, animal and vegetable organisms frequently developed in infusions of decaying organic substances. The Infusoria in this sense comprehended various desmids, diatoms, and other low plants, with many protozoan animalcules, and also rotifers or wheel-animalcules. Some of these organisms were known to Linnæus, and thrown by him into a genus which he called Chaos, at the end of his class Vermes. Lamarck, Gmelin, and others followed Müller in his understanding of Infusoria. Cuvier made Infusoria the fifth class of Radiata, divided into two orders, Rotifera and Homogenea. See Microzoa, Polygastrica.
  • infusoria A class of minute, mostly microscopic, animalcules, provisionally regarded as the highest class of Protozoa. They are endoplastic, having a nucleus; there is a mouth and a rudimentary stomach or gastric cavity; there are vibratile cilia or flagella, but no proper pseudopodia. Most are aquatic and free-swimming, and some are internal parasites; but others form colonies by budding, and when adult are fixed to some solid object. The body consists of an outer transparent cuticle, a cortical layer of firm sarcode, and a central mass of soft or semi-liquid sarcode, which acts as a stomach, and in which vacuoles may appear. A nucleus, which is supposed to be an ovary, having attached to it a spherical particle, the nucleolus, supposed to be a spermatic gland, is embedded in the cortical substance. Contractions of the body are effected by sarcode fibers. Reproduction takes place variously. The cilia or flagella are not only organs of locomotion, but form currents by which food is carried into the mouth. The Infusoria have been variously subdivided. A current classification is by division of the class into four orders, based on the character of their cilia or flagella, namely, Ciliata, Flagellata, Choanoflagellata, and Suctoria or Tentaculifera. By S. Kent, the latest monographer, the Infusoria are called a “legion” or superclass of Protozoa, and include the sponges; and they are divided into three classes, Flagellata or Mastigophora, Ciliata or Trichophora, and Tentaculifera.
  • ***

• • n.pl Infusoria in-fū-sō′ri-a a name given to several classes of active Protozoa, some of which appear in great numbers in stagnant infusions of animal or vegetable material
  • ***

In literature: