Euplotes

Euplotes is a genus of ciliates in the subclass Euplotia. Species are widely distributed in marine and freshwater environments, as well as soil and moss. Most members of the genus are free-living, but two species have been recorded as commensal organisms in the digestive tracts of sea urchins.

== Description == Euplotes cells are inflexible, dorsoventrally flattened, and roughly ovoid, with a very large oral region (peristome) bordered on the left by a long "adoral zone of membranelles" (AZM). Like other spirotrich ciliates, Euplotes move and feed with the help of compound ciliary organelles called "cirri," made up of thick tufts of cilia sparsely distributed on the cell. Strong cirri on the ventral surface of the cell enable Euplotes to walk or crawl on submerged detritus and vegetation. All species of Euplotes have a group of stiff bristles (caudal cirri), which protrude from the posterior of the cell. The number of caudal cirri varies, even within a species, but it is most common for Euplotes to have 4 or 5. The macronucleus is typically long and narrow, and approximately horseshoe-shaped, C-shaped, or resembling the number 3.