The plagiopylids are a small order of
ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...
s, including a few forms common in anaerobic habitats.
The body cilia are dense, and arise from
monokinetids with an entirely unique ultrastructure; one or two rows of