This sets them apart from the predominantly sessile peritrichs of the order Sessilida, such as Vorticella and Epistylis, which, during the feeding, or vegetative, phase of the life cycle remain attached to submerged surfaces, often by means of a stalk.

Ciliature on the body is restricted to a posterior wreathe called the "trochal band," made up of three rings of cilia girdling the aboral region of the cell.

Some molecular phylogenetic studies, based mostly on small subunit rRNA, have raised doubts that Mobilida and Sessilida are sister taxa, indicating that the groups belong to separate lineages within the class Oligohymenophorea.

[11] More recently, in a revised classification of Ciliophora drawing on both molecular and morphological data, researchers have reaffirmed the traditional grouping of Mobilida with Sessilida.

[12] A phylogenomic study released in September, 2016 robustly supports the classical view that Mobilida and Sessilida are sister clades within a monophyletic Peritrichia.