paramecium science definition

Any of various freshwater protozoans of the genus Paramecium that are usually oval in shape and that move by means of cilia. Although they consist of a single cell, paramecia are large enough to be visible to the naked eye. Like other ciliates, paramecia contain two nuclei, a macronucleus and a micronucleus. On the cellular surface is a groove that opens into a gullet, into which food particles are absorbed.