They typically have a prominent adoral zone of membranelles circling the mouth, used in locomotion and feeding, and shorter cilia on the rest of the body.

[1] These include some of the largest protozoa, such as Stentor and Spirostomum, as well as many brightly pigmented forms, such as certain Blepharisma.

The cilia on the body are in dikinetids, in which either the anterior one or both kinetosomes may be ciliated, and which are associated with fibers composed of overlapping postciliary microtubules, called postciliodesmata and found only in this group and the closely related Karyorelictea.

[6] Early classification schemes by Otto Bütschli, Alfred Kahl, Emmanuel Fauré-Fremiet, and John O. Corliss classified the heterotrichs as a subgroup of spirotrichs.

However, more recent classification systems, which have incorporated information from molecular phylogenetics, place the above groups within the Intramacronucleata, because they are not closely related to the "core" heterotrichs at all.