The ciliates. One of the most familiar groups of protozoa, distinguished by usually having many cilia lying in rows on the body and used for movement, sometimes with more cilia around the mouth and used for feeding. Typically between 10 and 500 microns in length. One of the characteristics that is very unusual is that ciliates have two kinds of nuclei - diploid micronuclei and selectively polyplopid macronuclei within each cell.