He defined them as possessing radial instead of bilateral symmetry, and as apparently destitute of nervous system and sense organs, as having the circulatory system rudimentary or absent, and the respiratory organs on or coextensive with the surface of the body; he included under this title and definition five classes, - Echinodermata, Acalepha, Entozoa, Polypi and Infusoria.
Leeuwenhoek, to whom we also owe the discovery of Bacteria and ciliate Infusoria.
In most rotifers, on the contrary, the trochus is stronger than the cingulum, often lobed, and with some of its cilia aggregated into vibratile styles homologous with the combplates of Ctenophora (q.v.) and the membranelles of ciliate Infusoria (q.v.).
Passing over the earlier authors who regarded this group as allied to Infusoria, a view c ar first contested by Dujardin, T.
C. Williamson (best known as a botanist) in Pritchard's Infusoria, in 1861.
Pritchard's History of the Infusoria (1861); C. T.
Lankester, " On Undulina, the type of a new group of Infusoria," Quart.
He was also a diligent and skilful observer, and busied himself not only with astronomical subjects, such as the double stars, the satellites of Jupiter and the measurement of the polar and equatorial diameters of the sun, but also with biological studies of the circulation of the sap in plants, the fructification of plants, infusoria, &c.
Ehrenberg adds a list of 8 Polygastric Infusoria, 1 fossil infusorian, 5 Phytolitharia and several microscopic fungi.
Ehrenberg), a genus of suctorial Infusoria characterized by the possession of a stalk and cupshaped sheath or theca for the body, and endogenous budding.
GASTROTRICHA, a small group of fairly uniform animals which live among Rotifers and Protozoa at the bottom of ponds and marshes, hiding amongst the recesses of the algae and sphagnum and other fresh-water plants and eating organic debris and Infusoria.
The only evidence we have in pathology of living structures in which apparently a differentiation into cell-body and nucleus does not exist, is in the case of bacteria, but then there comes the question whether they may not possess chromatin distributed through their substance, in the form of metachromatic points, as is the case in some infusoria (Trachelocerca, Gruber).
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.