Not only was he the first discoverer of the rotifers, but he showed "how wonderfully nature has provided for the preservation of their species," by their tolerance of the drying-up of the water they inhabit, and the resistance afforded to the evaporation of the fluids of their bodies by the impermeability of the casing in which they then become enclosed.
- Diagrammatic Views of Disks of Rotifers: cingulum continuous; trochus dotted; groove shaded; mouth black.
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.).
Most free rotifers swim by the corona, aided by the ciliated auricles when present.
The whole ovary is unilateral and unpaired in most rotifers; symmetrical in Asplanchnaceae, Philodinaceae and Seisonaceae.
The males of rotifers are of relatively rare occurrence, except in the genus A splanchna, where they were first recognized as such by Brightwell in 1841; though those of Hydatina had long since been seen and described as a distinct genus.
We may note that it was long since shown that the apical organ (at first assumed to be the brain) of these larvae was innervated from an anterior thickening of the circular nerve ring, corresponding with the brain of Rotifers; the nerve cells immediately below the pit are the ordinary bipolar From H.
Moreover, the body cavity of the rotifers is a primitive archicoele; the persistent or accrescent cleft between epiblast and hypoblast, traversed by mesenchymal muscular bands.
Thus we regard Rotifers as an independent stem branching off at the outset of the rise from the Platode type to higher Invertebrata The Polyzoa (q v), which in many ways recall Rotifers, appear to be equally independent.
The following classification of rotifers is our modification of that of Hudson and Gosse, further altered through considerations put From H.
As rotifers are common in ponds, the first workers with the microscope observed them repeatedly, the first record being that of John Harris in 1696, who found a Bdelloid in a gallipot that had been standing in his window.
Ehrenberg included the Rotifers in his Infusionsthiere, and described and figured with fair precision many of the genera and species.
Leeuwenhoek, in 1719, made the remarkable discovery, since abundantly confirmed, that many animalculae, notably tardigrades and rotifers, may be completely desiccated and remain in that condition for long periods without losing the power of awaking to active life when moistened with water.
Later observers have found similar occurrences in the cases of small nematodes, rotifers and bacteria.
This, however, is not the character to which we now ascribe the chief weight as evidence of the genetic affinity and monophyletic (uni-ancestral) origin of the Chaetopods, Rotifers and Arthropods.
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.
Those that are usually dwelt on are treated with the Rotifers and Nematoda and Turbellaria.