The
peritrichs (Latin:
Peritrichia) are a large and distinctive group of
ciliate protozoa. They are usually bell or disc shaped, with a prominent paroral membrane arising from the oral cavity and circling counter-clockwise around the anterior of the cell, accompanied by a smaller series of
membranelles. The oral cavity is apical and funnel shaped, with a
contractile vacuole discharging directly into it. When disturbed, the anterior of the cell can contract. The rest of the body is unciliated, except for a
telotroch band circling the posterior in mobile species and stages.