Infusoria
[ in-fyoo-sawr-ee-uh, -sohr- ]
/ ˌɪn fyʊˈsɔr i ə, -ˈsoʊr- /
plural noun
protozoans of the phylum Ciliophora (or class Ciliata).
(formerly) any of various microscopic organisms found in infusions of decaying organic matter.