Haptoria includes mostly carnivorous forms such as Didinium, a species of which preys primarily on the ciliate Paramecium.

[2][3] In litostomes, the body cilia arise from structures in the cell cortex called monokinetids, which are made up of a single cilium and its associated structures, such as basal bodies and microtubular fibres.

In one order, the Entodiniomorphida, the cilia are arranged into tufts or bands, and may be packed together to form syncilia, resembling the membranelles and cirri of spirotrichs (with which they were originally classified) and other ciliates.

In haptorians the mouth is typically surrounded by a ring of coronal cilia, arising from dikinetids derived from the anterior of the body kineties, and a ring of characteristic extrusomes called toxicysts.

The cytopharynx takes the form of a straight tube, supported by rods or nematodesmata, which dilates greatly during ingestion.